Bypass surgery may increase the risk of microscopic blood clots in the brain, and cause memory loss and other problems after surgery, according to new American research.
In a study of brain specimens from 36 adult patients who died within three weeks of cardiopulmonary bypass surgery 24 with coronary artery bypass grafts (CABG) and 12 cardiac valve repair microemboli were found in the arteries and capillaries in all specimens.
According to researcher John Hammond, the deposits found in the brain probably represent oily emboli which originated from the blood salvaged from the pericardium during surgery and recycled by being pumped back into the body.
The scientists also found that the number of microemboli increased by 90.5 per cent for each hour's increase in duration of surgery. Those undergoing valve repair (the longer type of surgery) had, on average, 46.2 per cent more microemboli than those in the CABG group (Stroke, 2000, 31: 707-13).
Betacarotene redeemed as a treatment for cancer
Precancerous lesions in the mouth may regress when patients are given betacarotene, says a new study.
In a recent multicentre, double blind, placebo controlled trial, 54 subjects were given 60 mg of beta carotene daily. After six months, 26 (52 per cent) were shown to have a clinical response.
These responders were then randomised into either beta carotene or placebo groups for further monitoring over a period of 12 months.
Interestingly, responders had a lower intake of dietary fibre, fruits, folate and vitamin E supplements than did non responders.
During the study, the rates of relapse were similar for both groups: 18 per cent for those who'd taken beta carotene versus 17 per cent in the placebo group, suggesting that the treatment must be kept up.
Biopsies performed initially in all patients found that dysplasia (abnormal cells) were present in 38 per cent of the subjects. Of these, there was an improvement after supplementation of at least one grade of dysplasia in 39 per cent and no change in 61 per cent (Arch Otolaryngol Head Neck Surg, 1999; 125: 1305-10).
Booster jabs for diphtheria not effective
The diphtheria booster may be ineffective at least one fifth of the time, according to a new study.
To test the effectiveness of the single adult booster, Belgian researchers recruited 176 adult volunteers, all of whom had been immunised during childhood.
>From blood tests, 39 per cent of these subjects were susceptible to diphtheria and 43 per cent were considered immune. The rest had limited immunity.
After receiving boosters, 76 per cent were immune. Of those who were not protected before the jabs, around half remained susceptible. Age was a major determinant of immunity, with older people less likely to have adequate antibodies before or after the booster.
These data suggest that nearly a quarter of adults receiving diphtheria boosters may still be inadequately protected.
Ongoing diphtheria epidemics in Eastern Europeand a worldwide increase in diphtheria cases have raised serious questions about the long term effectiveness of the diphtheria vaccine (BMJ, 2000; 320: 217).
Supplements ease pain of arthritis
The supplements glucosamine and chondroitin can ease the symptoms of arthritis, says a recent report from Boston University.
Researchers analysed 15 studies of the supplements used to treat osteoarthritis of the knee and/or hip conducted between 1966 and 1999. Their findings suggest that both supplements had moderate to large effects on the symptoms of arthritis, with chondroitin the more beneficial of the two.
Researchers believe that sufferers may benefit from these animal extracts chondroitin is an extract of beef cartilage and glucosamine an extract of crab shell because they purportedly help the body repair its own cartilage.
Both supplements have also been shown to have antiinflammatory effects and, unlike NSAIDs, the
most commonly prescribed treatment for OA, chondroitin and glucosamine have no adverse effects.
However, the research team cautioned that the quality of the studies reviewed was not always consistent and most of the studies were sponsored by manufacturers of the dietary supplements.
Nevertheless, as pointed out in the accompanying editorial, such flaws are unlikely to be any greater than those which beset medical trials of NSAIDs (JAMA, 2000, 283: 1469-75, 1483).
Medical mistakes: doctors say the system's to blame
A recent US document published by the Institute of Medicine showed that up to 98,000 people die in the US each year due to medical error more than die in motor vehicle accidents.
In response to the report, UK psychologists Charles Vincent (University College London) and James Reason (University of Manchester) believe that errors committed by doctors must be viewed in the context of the complex organisational systems in which they work and, when a doctor fails, it is due to a lack of support from the system.
In the same issue (Lancet, 2000; 355: 947-8), however, R.E. Ferner and J.K. Aronson, of the West Midlands Centre for Adverse Drug Reaction Reporting, also noted that the healthcare profession has lagged far behind other high risk professions in its efforts to reduce risk.
The search for a work able plan to protect patients from medical errors continues. The US Congress has proposed a bill the Medical Error Reduction Act whichwould make the reporting and studying of medical errors compulsory.