- Growth Hormone (GH) treatment reverses early atherosclerotic changes in GH-deficient adults
Full source: Pfeifer M, et al. 1999. J Clin Endocrinol Metab 84:453-57
The first study of its kind shows that supplemental growth hormone reverses the early stages of heart disease. Researchers in Slovenia and the UK report that recombinant GH stops an early symptom of heart disease known as intima media thickening. The intima media is the middle part of the artery. It consists of smooth muscle and flexible tissue. The smooth muscle contracts to help blood flow. In the early stages of atherosclerosis, the intima media becomes thickened. This constricts blood flow and impedes dilation of the artery.
Eleven men with low levels of pituitary hormone were given GH injections for a year-and-a-half. All of them started out with thickened intima media, which is common in people lacking GH. By six months, intima media and blood flow were normal. The beneficial effects were through insulin-like growth factor (IGF-1) which probably works by increasing nitric oxide. Nitric oxide keeps smooth muscle cells from growing, inhibits blood cells from sticking together, and controls dilation of the blood vessels.
Although the men in the study were given injections of recombinant GH which is very expensive, similar results may be achieved with factors that cause the release of growth hormone. Certain amino acids, including L-arginine, are known to increase GH and increase nitric oxide.
- Purple grape juice may slow arterial disease
Full source: Presented at the American College of Cardiology meeting in March. Studies funded by grants from Welch Foods, Inc., Concord, Massachusetts; the Oscar Rennenbohm Foundation of Madison, Wisconsin; and the Nutricia Research Foundation in the Netherlands.
Drinking purple grape juice may slow the development of coronary artery disease. A study released last year indicated that grape juice consumption could be linked to decreased activity of platelets (blood components important in clotting). Results from a new study of 14 people with stable heart disease suggest that drinking purple grape juice led to slower oxidation of LDL ("bad") cholesterol, one step in the development of arterial disease. LDL cholesterol is called the "bad" cholesterol because of its links to atherosclerosis, or clogged heart arteries. LDL cholesterol, when it's elevated, is harmful to the arterial wall. If it is oxidized by free radicals, molecules in the blood become unbalanced and hyperactive.
Oxidation, a chemical reaction that adds oxygen to LDL molecules, is thought to be one step in the development of diseased arteries. Flavonoids, substances found in purple grape juice and red wine, appear to delay oxidation of LDL, and may slow this process. Patients with coronary artery disease who drank purple grape juice had better protection for their LDL cholesterol from oxidation. This study was conducted by the director of the Coronary Thrombosis Research and Prevention Laboratory at the University of Wisconsin Medical School. They found that the blood samples of study participants who drank grape juice daily for 2 weeks had delayed LDL oxidation, even if they were already taking the antioxidant vitamin E. The participants in the oxidation study drank between 12 and 14 ounces of purple grape juice per day. Purple rather than white grape juice is being studied because purple grape juice and red wines have 7 or 8 as many of these flavonoid compounds, compared with white wine or white grape juice, partly in the way they're made and partly the selection of the grape. Another study presented linked purple grape juice to an improvement in the ability of endothelial cells, which line arteries, to dilate at times when increased blood flow is important, such as times of physical stress. In those with coronary disease, these endothelial cells were sick or dysfunctional, and by feeding them purple grape juice for a 14-day period, there was a significant improvement in the activity of these cells. The vessels were better able to dilate, or enlarge themselves at a time when you'd want them to do that.
These effects are not gained by eating grapes or raisins. The problem with eating grapes is that many of the grapes now are seedless, but grape juice is made from grapes that have the seeds, and about a third of the beneficial substances are in the seeds, and come out of the seeds when the juice is made. In addition, some of the stems of the grapevine get into grape juice and into red wine, and there are some favorable compounds in the stems.
Raisins are also made from a seedless grape, so some of the benefit is missed. Diabetics really shouldn't have grape juice because it has so much sugar. Flavonoid supplements may be a good alternative. The results of this study are not surprising, because there are more flavonoids in the colored skins of grapes, than in the grape flesh itself. It doesn't matter whether fermentation has occurred, so purple grape juice may be just as beneficial to our health as red wine.
- Even at low levels, HIV continues to mutate
Full source: Molecular Biology and Evolution 1999;16(3):372-382
HIV continues to mutate and develop resistance to drugs used to combat it, even among those on anti-retroviral drug therapy with extremely low levels of HIV in their blood, and even in patients with no detectable levels of virus. In this study researchers analyzed DNA sequences from eight HIV-infected patients taking combination protease inhibitor drug therapies. They tracked mutations in these gene sequences over a period of more than one year. Most of the patients had good responses to therapy, and the number of viruses in their blood, their "viral load," had fallen to near-undetectable levels on standard tests. However, more sensitive tests revealed that 5 of the 8 patients had experienced some rebound in viral load. Genetic studies revealed "significant evolution of virus from initial to final time points, even in 3 of 8 patients who had low viral loads."
This continuing evolution, or mutation, of the virus may someday allow it to escape the HIV-suppressant powers of today's drug cocktails, the researchers explained. "Eventually, the virus is going to find a solution to the drug therapy." However, the good news is that each of the five patients with mutated HIV displayed near-identical changes in viral structure. This "parallel evolution" suggests that the virus has a limited number of solutions to evolve around this drug therapy. We can now take these changes and build better drugs that can block these sorts of changes. In this way, scientists might be able to create the next generation of protease inhibitor therapies in advance of a crisis. "Mutation" indicates continued replication of the virus. However, as long as HIV replicates, pockets of it, or "reservoirs," will continue to survive in the body despite therapy. Researchers are hopeful that some day long-term samples of HIV will turn up no evidence of genetic evolution. That would suggest that these reservoirs are not being replenished, and that they're being depleted. "In those types of cases, drug therapy has a chance in some patients to actually be a cure," they explained. However, if there's a continual restocking of these viral reservoirs, then there's not much hope that drug therapy will become a cure.
- Vitamin deficiency may cause hearing loss
Full source: American Journal of Clinical Nutrition 1999;69:564-571
Deficiencies in vitamin B-12 or folic acid may lead to hearing loss in elderly women. Although hearing loss is common in elderly people, the biological mechanisms that cause age-related hearing impairment remain unknown. Both of these nutrients play important roles in maintaining efficient blood flow and nervous system function. In this study, investigators assessed hearing function as well as blood levels of both vitamin B-12 and folic acid in a group of 55 healthy women, aged 60 to 71.
They found that women with impaired hearing had 38% lower blood vitamin B-12 and 31% lower red cell folic acid than women with normal hearing. Hearing loss in the elderly may be due to changes in the cochlea, a tiny shell-shaped organ in the inner ear that translates sound into electrical impulses that can be read by the brain. The cochlea is supported by a single artery, making it especially vulnerable to restrictions in blood flow brought about by vitamin B-12 or folate deficiency. It is not known whether supplements of vitamin B-12 or folate would improve hearing function or slow the rate of hearing loss in elderly individuals. However, in Cuba in 1992-1993, widespread vitamin deficiency was linked to hearing loss in many individuals. Cuban experts later reported that vitamin B supplementation 'produced rewarding results.' This study also provides further evidence of chronic vitamin deficiencies, not detectable in routine physical exams and standard laboratory testing, causing significant physiologic impairment.
- Bad hearts and stress can be deadly
Full source: Presented at the American College of Cardiology in New Orleans. The study was financed by the National Heart, Lung and Blood Institute. [A poignant example of the deadly effects of stress, the 66 year old Emir of the Gulf Arab state of Bahrain Sheikh Isa bin Sulman al-Khalifa died recently of a heart attack less than 30 minutes after meeting with U.S. Defense Secretary William Cohen.]
Speaking in public may be more than just terrifying. The stress may be deadly. A recent study found that people whose hearts show ominous signs of poor circulation during such mental challenge face 3 times the usual risk of death in the years to come. Often people with bad hearts suffer chest pain during exertion. Their clogged arteries cannot supply enough blood to their heart muscle. However, over the past decade, it has become clear that mental exertion can also overwork the heart, although often without pain. Doctors call this condition "silent ischemia." No studies until now have been large enough to prove that mental stress can actually be fatal for people with coronary artery disease. The latest study demonstrates just how dangerous this can be for the heart. It found the annual death rate is about 4 % among people whose hearts have bad circulation during mental stress. This is more than triple the risk faced by heart disease patients who do not react this way to mental stress. In the study, the researchers found that public speaking is a particularly potent trigger of this heart problem. However, they said that probably anything that causes mental stress is risky for these people. The researchers gave three days of tests to 173 men and women with heart disease. They were asked to imagine that a relative had been mistreated in a nursing home. Then they were given two minutes to prepare a speech about the problem and five minutes to deliver it before an audience.
Blood pressures' typically rose about 40 points. Radionucleotide scanners watched their hearts. In half the volunteers, sections of the muscle of the left ventricle began to beat erratically. Eleven of them died during three to four years of follow-up. Forty-four percent of these victims had shown the erratic heartbeats during public speaking, while 18% did not. Participants whose hearts reacted badly on the test seemed no more nervous or tongue-tied than those who weathered the stress without problems. The study identified people with a heightened response to stresses that may lead to a heart attack. Earlier studies have shown that such hardships as depression, the death of a spouse, losing a job or living through an earthquake increase the risk of fatal heart attacks. However, those studies did not test victims ahead of time for silent ischemia during mental stress.
- Skin cancer risk after heart transplant
Full source: Journal of the American Academy of Dermatology 1999;40:27-34
Early and frequent skin examinations of those who have undergone a heart transplant may help reduce their risk of dying from skin cancer. The use of drugs that suppress the immune system to prevent rejection of a transplant also predispose patients to skin malignancy. Studies have also shown that the rates of skin cancer are higher in patients who have received a heart transplant than in those who have had a kidney transplant. This is attributed to the slightly higher doses of immunosuppression agents used in heart transplantation compared with other solid organ transplants. The study at the Skin and Cancer Foundation in Australia, included 400 patients undergoing heart transplantation in a country with one of the highest rates of skin cancer in the world, and a leading cause of death. Patients' ages ranged from 6.6 years to 67 years at transplantation, with a median age of 47.9 years. Results showed that 31% of patients developed skin cancer after five years and 43% developed skin cancer after ten years. Skin cancer accounted for 27% of the 41 deaths that occurred after the fourth year. The findings reinforce the need to conduct regular skin examinations of heart transplant patients so that lesions can be treated early, given the risk of progressive tumors and metastasis. People must be educated regarding the need for sun protection and to regularly carry out self-examination.
- Carotid artery disease reflects family risk
Full source: Arteriosclerosis, Thrombosis, and Vascular Biology 1999;19:366-371
People whose parents died from coronary heart disease (CHD) are more likely to have a buildup of plaque in their carotid arteries, which may indicate their risk for arterial diseases including heart attack and stroke, report French researchers. They studied how the risk of heart disease in one generation was reflected in their children by examining the association between parental history of premature death from CHD and the incidence of plaque in the carotid arteries in their children. The carotid arteries are found in the neck, and carry much of the blood supply of the brain. The development of arterial disease affecting the lining of these arteries has been linked to an increased risk of arterial disease elsewhere in the body.
The study included 1,040 men and women aged between 59 to 71 years. Parental history of premature death from CHD occurred in 5.1% of the study participants, meaning that one or both parents died of a heart attack before the age of 65.
The investigators found that carotid plaques, as found on ultrasound examination, were significantly more common in both men and women whose parents died prematurely of CHD than in subjects with no familial history of premature death from CHD. However, the underlying reason for this association is unknown. The researchers suggest that further study of possibly inherited factors that lead to carotid plaques may lead to a better understanding of the risk of premature CHD death in families.
- Vitamins C and E protect lungs from ozone
Full source: American Journal of Epidemiology 1999;149:306-314
Daily supplements of vitamins C and E help counteract the negative effects of ozone on lung function in athletes. Previous studies have found that even low levels of ozone, an air pollutant, can have significant effects on lung function, evident as little as one hour after exposure. These effects have previously been studied in athletes exercising indoors, under laboratory conditions. Researchers studied the lung function of 38 Dutch bicyclists that trained outdoors over a 3-month period. Half the cyclists took daily doses of vitamin C (500 mg) and vitamin E (100 mg) for 15 weeks, while the other half took (inactive) placebo pills. Neither the researchers nor the bicyclists knew who was taking the antioxidants. From May 20 to the end of August 1996, lung function was measured in each subject on a number of occasions, both before and after each training session or competitive race.
In addition, tests measured concentrations of both vitamins in the cyclists' blood. Daily concentrations of ozone were obtained. The researchers found that relatively low concentrations of ozone in the areas where the cyclists trained did affect their lung function. The negative effect was stronger in the control group receiving placebo treatment, suggesting that supplementation with vitamins C and E was able to partially counteract the acute effects of ozone on lung function in heavily exercising subjects. The Dutch research team speculates that antioxidants may protect the lungs against some of the effects of ozone by reducing the lung's inflammatory response to the air pollutant.
- US experiencing heart failure 'epidemic'
Full source: Presented at the American College of Cardiology in Detroit
Cardiologists have been so successful in treating patients with heart disease that they have created an epidemic of heart failure, a chronic condition in which the heart pumps inefficiently, causing fatigue, breathlessness and fluid accumulation in the body. This study shows that the number of cases of heart failure treated at the Henry Ford Health System in Detroit, Michigan has more than doubled since 1989. Using an electronic database, the Detroit team tracked 26,442 patients over a 10-year period, checking for heart failure. The number of cases of heart failure increased from 9 cases per 1,000 in 1989 to 20 cases per 1,000 in 1997. According to the report, heart failure can be considered a chronic disease epidemic experienced by large health systems across the US today. Patients are getting better care and they're living longer. This represents a true epidemic. The increasing numbers of heart failure patients mean that healthcare officials need to use 'epidemic resource planning' to figure out how to care for them.
- Animal fat may raise prostate cancer risk
Full source: Journal of the National Cancer Institute 1999;91:414-428
A high intake of animal fat appears to increase the risk of developing prostate cancer. However, the exact mechanisms behind this association are not known. An estimated 200,000 US men will develop prostate cancer this year and 37,000 will die of the disease, according to the American Cancer Society. Prostate cancer is the second leading cause of cancer deaths in men, after lung cancer. Many studies have noted an association between high-fat diets and an increased risk of prostate cancer. This team reviewed scores of studies focused on the meat-cancer link, and conclude that men who eat a lot of meat and dairy products do appear to have a higher risk of prostate cancer. However, the researchers point out that this could mean either that meat and dairy foods are themselves involved in raising risks, or that some other factor in the men's diets put them at risk. For example, a high-meat/high-fat diet generally entails a lower intake of plant foods that contain possible protective factors against prostate cancer. On the other hand, meat contains zinc and high zinc intake has also been associated with raised risks for prostate cancer. Cooked meat also contains suspected carcinogens such as heterocyclic amines. It was speculated that the fat found in meat might affect levels of male hormones, which are known to impact on prostate cancer risk. This illustrates another reason to eat meat in moderation. Even a fat-trimmed prime quality steak is high in fat, because the 'marbling' that permeates the meat, making the meat tender, is composed of fat. In a related study, researchers at the University at Buffalo, New York, report that plant-based fats called phytosterols may reduce testosterone activity linked to prostate cancer. Previous studies have suggested that men living in primarily vegetarian cultures have lower rates of prostate cancer compared with men in Western, meat-eating nations. To help determine the link between vegetarianism and low risks for prostate cancer, one group of rats was fed a diet high in phytosterols and another group a normal rat diet. In rats fed the phytosterol-rich diet, levels of circulating testosterone and related enzymes fell by nearly 50% compared with rats on the normal diet. The reduction in testosterone did not affect sexual function. High testosterone levels have long been linked with higher risks for prostate cancer. Thus, the combined effect of reducing levels of testosterone and the activity of its two main enzymes suggest a diet high in foods containing phytosterols could help reduce the risk of prostate cancer.
- Immortality enzyme safe for human cells
Full source: Nature Genetics 1999;21:111-114, 115-118
Human cells immortalized in the laboratory with the enzyme telomerase, a recent achievement met with much excitement, do not transform into cancerous cells, according to results of new research. This paves the way for the use of immortalized cells to treat patients with leukemia, genetic disorders, and potentially a variety of other diseases. Most cells only divide about 75 to 80 times before dying, a process controlled by telomeres, a small piece of DNA found on the end of each chromosome. The telomere degrades with each cell division, and gradual shortening of the telomere signals the cells to die. Recently, a team of researchers discovered that introducing the enzyme telomerase, which builds up telomeres in certain cells, could essentially 'immortalize' normal human cells by inhibiting this progressive shortening. This ability to immortalize cells has enormous clinical implications. If researchers could obtain only a few rare stem cells from a leukemia patient, cells that have the ability to reconstitute the immune system, they could be immortalized, grown in large quantities and transplanted back into the patient with no risk of rejection, and avoiding a bone marrow transplant. A similar strategy could be used to correct genetic defects in patients with genetic disorders. However, there has been concern that the association of telomerase with cancer implies that normal cells expressing telomerase would have the characteristics of cancer cells. About 85% to 95% of all cancer cells have telomerase. One reason cancer cells are dangerous is because they are 'immortal' and have lost the natural brakes on uncontrolled cell growth. In this study, the team offers new evidence that normal cells that are manipulated to express telomerase exhibit absolutely none of the characteristics that one associates with tumor cells.
The long-term forced expression of telomerase by human cells grown in the laboratory did not result in any of the changes typically associated with cancer cells. The cells did not develop chromosome abnormalities or lose contact inhibition, a normal process in which cells stop growing when they come into contact with other cells. In a second study in the journal, researchers of the Geron Corporation in Menlo Park, California report similar findings.
The bottom line is that telomerase by itself does not make cells cancerous.
- Cardiac arrest drug tied to brain damage
Full source: Annals of Internal Medicine 1998;129:450-456, 501-502
The drug epinephrine has been used by emergency teams for decades during efforts to resuscitate patients who have suffered a cardiac arrest. Now researchers report that high doses of the drug may be linked to an increased risk of permanent, severe brain damage. According to this study, survival with favorable functional neurologic recovery seems to be unlikely after administration of high doses of epinephrine. Current American Heart Association (AHA) guidelines recommend that patients first receive 1 milligram (mg) of epinephrine every 5 minutes during cardiac resuscitation.
The AHA says this dosage may then be increased if deemed clinically necessary. The Austrian team examined the postresuscitation outcomes of 178 patients treated by emergency teams for cardiac arrest between 1991-1995. They report that the restoration of spontaneous circulation was possible with increasing cumulative doses of epinephrine, but good functional neurologic recovery was less likely. The researchers say that risks for poor neurologic outcomes increased as the overall dose of epinephrine delivered during resuscitation increased. Only 2 of the 36 patients revived using high-dose epinephrine left the hospital without severe functional neurologic impairment. Even after taking the duration of resuscitation into account, they found that the cumulative epinephrine dose remained an independent predictor of unfavorable neurologic outcome. Their findings may pose a dilemma for emergency teams. Without a working heart, the brain cannot be perfused (supplied with blood). On the other hand, cardiac resuscitation using high-dose epinephrine may leave patients with "beating hearts but nonfunctioning brains." New data for the AHA cardiac resuscitation guidelines are needed on the use of high-dose epinephrine. These results should serve as a possible warning against the indiscriminate use of epinephrine in the emergency room. The researchers concluded that,"Perhaps the casual attitude of emergency care providers toward the administration of large amounts of epinephrine during cardiac arrest should end."
- Folic acid deficiency tied to heart risk
Full source: Presented at the European Society of Cardiology in Vienna in August
An apple a day may keep the cardiologist away, according to a Greek physician. A study has found that heart disease patients who have a folic acid deficiency are more likely to have a heart attack than those with adequate intake of the nutrient are. Folate, a B vitamin, is found in fruit and green leafy vegetables. The research group studied blood levels of cholesterol and vitamins in three different groups of patients in Northern Greece: 1) patients who had recently had a heart attack, 2) those with stable coronary artery disease, and 3) a group of healthy people. They found that blood cholesterol levels seem to have little association with the incidence of heart attack. In contrast, low levels of folic acid were closely related to the occurrence of acute heart attacks. In patients with documented coronary artery disease who became deficient in folic acid, the probability of heart attack was 1.7 times that of heart disease patients who had normal levels. Folic acid, vitamins B-6 and B-12 lower the blood level of homocysteine, an amino acid that is more closely tied to heart attacks than is cholesterol.
- Oxidative stress and antioxidant and HIV infection
Full source: American Journal of Clinical Nutrition, 1998, Vol 67, Iss 1, pp 143-147
Increased lipid peroxidation induced by free radicals plays a role in the stimulation of HIV replication. This study compared lipid peroxidation indexes and plasma antioxidant micronutrients between two groups: 1) 49 nonsmoking HIV-positive patients with no active opportunistic infection (25 asymptomatic and 24 with AIDS), and 2) 15 age-matched seronegative control subjects. Breath-alkane output, plasma lipid peroxides, antioxidant vitamins, and trace elements were measured. Results showed that the following concentrations were significantly lower in the HIV-positive patients: vitamin C (40.7) compared with (75.7) mu mol/L, vitamin E (22.52) compared with (26.61), beta-carotene (0.23) compared with (0.38), and selenium (0.37) compared with (0.85). Lipid peroxides were significantly higher in the HIV-positive patients: (50.7) compared with (4.5) mu mol/L, breath pentane (9.05) compared with (6.06) pmol.kg, and ethane output (28.1) compared with (11.42) pmol.kg . These results showed an increase in oxidative stress and a weakened antioxidant defense system in HIV-positive patients. Whether supplementation of antioxidant vitamins will reduce this oxidative stress is still unknown.
- Watchful waiting or watchful progression?
Full source: Cancer, 1998, Vol 82, Iss 2, pp 342-348
Prostate specific antigen doubling time (PSAdt) predicts aggressive prostate disease and subsequent clinical recurrence after radical treatment. However, yet there is only limited evidence for its validity in the watchful waiting population. In this study, 113 previously untreated patients (ages 49-85) with prostate cancer were placed into a prospective watchful waiting program. The reasons for watchful waiting, previous medical history, serial PSA, and histopathologic data were recorded. The median follow-up from the time of the first appointment was 14 months (range 0-58 months). Approximately 51% had cancer progression by 2 years, increasing to 60% at 3 years. The initial PSA was only significant in predicting for time to treatment.
Approximately 50% of patients with a PSA doubling time of less than 18 months progressed within 6 months. At last follow-up, no deaths from prostate cancer had been recorded. Overall survival at 2 and 5 years was 92% and 68%, respectively. The findings demonstrated high rates of tumor progression within the watchful waiting population. PSA doubling time was found a more powerful indicator of disease activity than standard tissue pathologic criteria.
- Vitamin E pretreatment decreases lung leakage
Full source: Journal of Applied Physiology, 1998, Vol 84, Iss 1, pp 263-268
This study looked at whether direct administration to the lungs of vitamin E would decrease acute oxidative lung injury. A previous study showed that administering vitamin E to rats increased lung vitamin E levels and decreased white blood cell-mediated lung leak. In this study, pretreatment with vitamin E protected isolated rat lungs against the oxidant-induced lung leak caused by perfusion (flow of blood) with an enzyme system that generates free radicals. Isolated rat lungs perfused gained more weight, retained more lymphocytes, and accumulated more lymphocytes in their lung than control lungs. In contrast, isolated lungs from rats that were not pretreated with vitamin E had decreased weight gains, lymphocytes lymphocytes retentions, and lung lymphocyte concentrations after perfusion compared with isolated lungs from control rats perfused. The results suggest that direct lung supplementation of vitamin E decreases susceptibility to vascular leakage caused by enzyme derived oxidants.
- Finasteride and PSA levels in men with BPH
Full source: Journal of Urology, 1998, Vol 159, Iss 2, pp 449-453
Finasteride therapy for benign prostatic hyperplasia (BPH) (enlargement) results in a marked lowering of serum prostate specific antigen (PSA) levels. However, little is known about the effect of finasteride on unbound or free serum levels of PSA. Such information would be important since percent free PSA may substantially improve the cancer specificity of PSA testing. Forty men with BPH (ages 52 to 78) were treated with either a) 5 mg. Finasteride daily (26 for 9 months) or placebo (14 for 6 months). In the finasteride group, mean total PSA levels declined from 3.0 Ng/ml to 1.5 Ng/ml. After 6 months, there was a 50% decrease in PSA levels. In the placebo group, there was no significant change. PSA density declined significantly in finasteride treated men but not in men receiving the placebo. The mean percent free PSA (13 to 17% at start) was not altered significantly by finasteride or placebo. Thus, total PSA serum levels decreased by an average of 50% during finasteride therapy but percent free PSA did not change significantly. This information is potentially useful in the interpretation of PSA data used for early detection of prostate cancer in men receiving finasteride. However, further studies are required to demonstrate the use of percent free PSA to detect the development of cancer.
- Soy decreases toxicity in the gastrointestinal tract
Full source: Nutrition and Cancer - an International Journal, 1997, Vol 29, Iss 3, pp 217-221
The ability of soy to inhibit methotrexate-induced gastrointestinal toxicity was examined. Rats treated with methotrexate were fed diets containing casein (milk protein) as a sole protein source or diets supplemented with a protein-phospholipid portion isolated from soy flour. Soy protein has been shown to inhibit programmed cell death (apoptosis) in mouse embryonic cells.
Rats that received high doses of the soy-derived anti-apoptotic portion supplemented diets experienced significantly less weight loss and diarrhea and better maintained their pretreatment appetite.
- Cancer prevention by natural carotenoids
Full source: Journal of Cellular Biochemistry 1997 Supple 27, pp 86-91
Investigations have shown that cancer risk is diminished as the consumption of green and yellow vegetables and fruits increase. Since beta-carotene is present in abundance in these vegetables and fruits, it has been investigated extensively as a possible cancer preventive agent. However, various carotenoids that coexist with beta-carotene in vegetables and fruits also have anti-cancer activity. Some of them, such as alpha-carotene, showed higher potency than beta-carotene in suppressing experimental cancer.
Lycopene and lutein have also been found to have potent anti-cancer activity. This study confirms the cancer-preventative activity of phytoene biotechonologically when mammalian cells producing phytoene were resistant to induced cell transformation. Further studies on various natural carotenoids besides betacarotene should be continued to obtain more information about the potential of natural carotenoids in the field of cancer prevention.
- A relation between melatonin deficiency and endometrial cancer
Full source: Gynecologic and Obstetric Investigation, 1998, Vol 45, Iss 1, pp 62-65
Endometrial cancer is the most common pelvic genital cancer in women; its incidence is increasing. Unlike the successful screening method for cervical cancer, there is no such equivalent procedure for the early diagnosis of endometrial cancer. Of 138 women selected, 68 women were diagnosed with endometrial cancer; and 70 patients (control group) had abnormal bleeding.
In addition to the routine hormone analyses, a significant correlation between blood levels of melatonin and the presence of endometrial cancer was found. The mean plasma melatonin value was 6.1 pg/ml (picograms - one-trillionth of a gram) in the cancer- positive group and 33.2 pg/ml in the cancer-negative control group resulting in a 6-fold difference between the two groups. It was concluded that melatonin blood levels that are decreasing, may be an indicator of endometrial cancer. This may therefore be used as a reliable screening parameter.
- Microwaving diminishes vitamin B-12 in foods
Full source: Journal of Agricultural and Food Chemistry, 1998, Vol 46 Jss 1, pp 206210
In this study, the effects of microwave heating on the loss of vitamin B-12 in foods, raw beef, pork, and milk were determined. Appreciable loss (30-40%) of vitaminB-12 occurred in the foods due to the degradation of vitamin B-12 molecules by the microwave. When hydroxo vitamin B-12, which predominates in foods, was microwaved and then analyzed, two vitamin B-12 degradation products were found. The vitamin B-12 degradation product did not show any biological activity. Administration of the vitamin B-12 degradation product (1 mg/day) for 7 days to rats showed that the compound neither has toxicity nor exhibits a blocking action of other substances in mammals. The results indicate that the conversion of vitamin B-12 to the inactive vitamin B-12 degradation products occurs in foods during microwave heating.
- Smoking, smoking cessation, and tooth loss
Full source: Journal of Deutal Research, 1997, Vol 76, Iss lO, pp 1653-1659
Smoking is associated with an increased risk of tooth loss. This study of 584 women (aged 40 to 70) and 1231 male veterans (aged 21 to 75) determined if this risk decreases significantly when individuals quit smoking. Current cigarette smokers of. either sex had significantly more missing teeth than never-smokers or former smokers. Former smokers and pipe or cigar smokers tended to have an intermediate number of missing teeth, and current male smokers had more teeth with calculus. Follow up of 248 women (6 years) and 977 men (18 years) indicated that individuals who continued to smoke cigarettes had 2.4-fold (men) to 3.5-fold risk (women) of tooth loss compared with non- smokers. The rates of tooth loss in men were signifi- cantly reduced after they quit smoking cigarettes but remained higher than those in nonsmokers. These findings indicate that the risk of tooth loss is greater among cigarette smokers than among non-smokers. Smoking cessation significantly benefits an individual's likelihood of tooth retention, but it may take decades for the individual to return to the rate of tooth loss observed in non-smokers.
- Effects of glucose/insulin system on aging
Full source: Journal of the American College of Nutrition, 1997, Vol 16' Iss 5, pp 397-403
Among changes associated with aging is a decline in glucose tolerance. It is the product of carbohydrate metabolism, and is the chief source of energy for living organisms, its utilization being controlled by insulin. The causes of the decline are increased insulin resistance and diminished pancreatic islet B-cell sensitivity to glucose. Many recent reports indicate that insulin resistance with hyperinsulinemia (increased levels of insulin) and/or hyperglycemia (excess glucose in the blood) contribute to or even cause many chronic disorders associated with aging, i.e., noninsulin-dependent diabetes mellitus, obesity, hypertension, lipid abnormalities, and atherosclerosis. In aging, similar to diabetes, elevated levels of circulating glucose and other reducing sugars can react with proteins and nucleic acids to form products that affect function and diminish tissue elasticity. In addition, disturbances in glucose/insulin metabolism are associated with enhanced lipid peroxidation caused by greater free radical formation. Free radicals cause tissue damage associated with many aspects of aging including inflammatory diseases, cataracts, diabetes, and cardiovascular diseases. Free radical formation and lipid peroxidation are not uncommon in diabetes mellitus, commonly associated with 'premature aging.' Ingestion of sugars, fats, and sodium have been linked to decreased insulin sensitivity, while caloric restriction, exercise, ingestion of chromium, vanadium, soluble fibers, magnesium, and certain antioxidants are associated with greater insulin sensitivity. Thus, manipulation of diet by influencing the glucose/insulin system may favorably affect lifespan and reduce the incidence of chronic disorders associated with aging.
- Suppression of tumors by dietary substances
Full source: British Journal of Clinical Pharmacology, 1998, Vol 45, Iss 1, pp 1-12
The concept that cancer can be prevented, or its onset postponed, by certain diet-derived substances is currently eliciting considerable interest from the medical community. Agents that interfere with tumor-development at the stage of promotion and progression in particular are of potential clinical value. As chemopreventive agents have to be administered over a long period in order to establish whether they possess efficacy in humans, it is of paramount importance to establish their lack of toxicity. This study discusses antioxidation, inhibition of arachidonic acid metabolism, modulation of cellular signal pathways, and inhibition of hormone and growth factor activity as mechanisms by which genistein from soy, the spice curcumin and retinoic acid exert tumor suppression. A better understanding of these mechanisms will help establish better screens for the discovery of new and better chemopreventive agents and the identification of biomarkers to assess the outcome of chemoprevention trials.
- Antioxidants counter L-dopa toxicity
Full source: Amino Acids, 1998, Vol 14, Iss 1-3, pp 189-196
L-dopa and its degradation products have been demonstrated to have neurotoxic potential in a number of cellular and in vivo experiments.
Several mechanisms have been hypothesized to be involved including the generation of prooxidant products that subsequentlv oxidize membrane lipids and exposed macromolecules. Researchers studied the toxicity of Dopa and the ability of various neuroprotective and anti-parkinsonian compounds to offer protection. This study is based on the ability of Dopa to cause an oxidative injury to brain cells. Potent antioxidants are effective blockers of Dopa toxicity. Catalase, superoxide dismutase, and glutathione (the body's natural antioxidants) showed the ability to protect the neurons from this toxicity. If the mechanisms involved in this toxicity have relevance to the progression of Parkinson's disease in Dopa treated (or untreated) patients. these antioxidant compounds have the potential to alter the course of the illness.
- Fish oil concentrate inhibits cancer in rat colon
Full source: Pharmacology & Toxicology 1998; Vol 82, Iss 1, pp 28-33
This study looked at whether a fatty acid concentrate derived from fish oil could inhibit the initial formation of cancerous tissue and the later growth of pre-existing cancer in the colon of rats treated with carcinogens. The concentrate was composed of 51% eicosapentaenoic acid, 35% docosahexaenoic acid, and 7% of other fatty acids. The results showed a dose-dependent reduction by 36% of the initial formation of cancer induced by the carcinogen. The reduction was most pronounced (46%) among the fastest growing cancers. This was sufficient to completely Nock the growth of the pre-existing cancers in the 6-week treatment period. Stopping the cancerous progression was further documented by the 63% reduction of the largest cancers.
- Mammography benefits women under 50
Full source: Cancer 1998;82:2221-2226
A breast cancer study that compared tumor detection and survival rates m younger and older women provides evidence that women under age 50 should get regular mammograms According to the study, clinical breast exams alone may not detect growing tumors early enough. However, researchers disagree on the benefits of mammography for younger women. While the technique has clearly improved breast cancer survival rates for women over 50, the benefits are not as clear for younger women, whose denser breast tissue makes the scans less effective at locating small tumors. The study compared the tumor sizes and survival rates of women whose tumors were first found by a mammogram to those women whose tumors were initially located by a conventional breast exam. Of 869 women, 37% had been diagnosed with breast cancer by a mammogram, and 63% had their tumors detected by a doctor during a breast exam. The researchers compared the average size of the tumors in women younger than and older than 50. Tumor size is important, since the likelihood of success- fully treating cancer and preventing recurrence is much higher if the tumor is detected early on, while it is still small. Women of all ages whose tumors were detected by mammography were first diagnosed when their tumors were about 1 centimeter (cm) in size. However, for women whose tumors were first found by clinical exam, there was a substantial difference in tumor size between younger and older women. The average size of clinically detected tumors for women over 50 was 1.5 cm. For women under 50, aver- age tumor size at detection was 2 cm, indicating that 'if left to grow to the size necessary for clinical detectability, the tumors are larger and more aggressive in younger women. They suggest that from an individual young woman's perspective the benefits of mammography are stronger than the drawbacks. Having a yearly mammogram after age 40 is the policy of the American Cancer Society.
- Piracetam inhibits blood clot formation
Full source: Thromhosis and Haemostasis, 1998; Vol 79, Iss 1, pp 222-227
Intravenous administration of piracetam significantly reduced clot formation in rats. Human platelet aggregation, induced by a variety of drugs, was also inhibited by piracetam. The broad inhibition spectrum could be explained by the capacity of piracetam to prevent fibrinogen binding to human platelets. A possible anti-clotting effect of piracetam could be due to the beneficial effect on red blood cell deformability. This could lead to a reduction of ADP release by damaged red blood cells. It was concluded that the anti-clotting action of piracetam cannot satisfactorily be explained by an isolated direct effect on platelets. It may be that piracetam may also influence the flow of blood and/or on the vessel wall itself.
- Neurosteroids and cognitive performance
Full source: Proceedings of the National Academy of Sciences of the United States of America, 1997, Vol 94, Iss 26, pp 14865-14870
Pregnenolone sulfate (PREG S) is synthesized in the nervous system and is a major neurosteroid in the rat brain. Significantly lower levels of pregnenolone were found in aged rats. When the spatial memory performances of aged rats were investigated, rats with lower memory deficit had the highest PREG S levels. In addition, the memory deficit of cognitively impaired aged rats was temporarily corrected after injection of PREG S into the hippocampus of the brain, and acetylcholine release was stimulated. PREG S may reinforce neurotransmitter systems that decline with age. It is proposed that PREG S in the hippocampus plays a physiological role in preserving and/or enhancing cognitive abilities in old animals, possibly via an interaction with central cholinergic systems. Thus, neurosteroids should be further studied in the context of prevention and/or treatment of age-related memory disorders.
- Anti-tumor treatment in post-menopausal metastatic breast cancer
Full source: British Journal of Cancer, 1998, Vol 77, Iss 1, pp 115-122
Suppression of the secretion of prolactin, growth hormone, and insulin-like growth factor 1 (IGF-1) might be important in the growth regulation and treatment of breast cancer. However, estrogen may counteract the anti-tumor effects of such treatment. Therefore, the combination of a triple endocrine therapy treatment vs. standard treatment with tamoxifen alone was tried. The therapy consisted of an anti-estrogen (tamoxifen), a somatostatin analogue (inhibits release of somatotropin by the pituitary gland, of insulin and glucagon by the pancreas, and of gastrin by the gastric mucosa), and a potent anti-prolactin. An analogue denotes a similar chemical structure with a different component. An objective response was found in 36% of the patients treated with tamoxifen alone and in 55% of the patients treated with combination therapy. The time period was 33 weeks for patients treated with tamoxifen and 84 weeks for patients treated with combination therapy.
However, the numbers are too small for hard conclusions. There was a significant decrease of plasma IGF-1 levels in both treatment arms, whereas during combined treatment growth hormone tended to decrease and prolactin levels were strongly suppressed. Combined treatment resulted in a more uniform suppression of IGF-1. This study also discusses the value of prolactin suppression when treating certain cancers. Prolactin can also be suppressed using the drug Dostinex with fewer side effects than bromocriptine (Parlodel).
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