Biomedical subjects
S K Gill
Publications and source records attributed to S K Gill.
Sugar-sweetened drinks.
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The transmissible spongiform encephalopathies (prion diseases): a review for dental surgeons.
The transmissible spongiform encephalopathies (prion diseases) are a fatal group of neurological diseases characterised by the accumulation of an abnormal form of prion protein in the brain. In humans, these disorders occur in sporadic, acquired and familial forms. Outbreaks of bovine spongiform encephalopathy, predominantly in the United Kingdom, and the emergence of a clinically and pathologically distinct human prion disease, variant CJD, has generated much interest in the transmissible spongiform encephalopathies. As the agent is detectable in lymphoid and neural tissue in variant CJD, clinicians should be aware of the possibility of cross infection of the causative agent. This is particularly important because the abnormal prion protein is resistant to routine sterilisation procedures. This article reviews the transmissible spongiform encephalopathies, and summarises guidelines concerning prevention of crossinfection when treating patients with or at risk of developing prion disease.
Time course of the effect of nifedipine therapy and its discontinuation on [Ca2+]i and phagocytosis of polymorphonuclear leukocytes from hemodialysis patients.
The abnormalities in [Ca2+]i and phagocytosis of polymorphonuclear leukocytes (PMNLs) from hemodialysis (HD) patients are significantly improved by their treatment with nifedipine. However, the rapidity with which this agent induces its beneficial effect and whether these derangements re-emerge after cessation of therapy are not known. We studied 5 HD patients before, during and after treatment with nifedipine. Before treatment with this agent, the basal levels of [Ca2+]i of PMNLs were markedly elevated 73 +/- 3.6 nM (normal: 42 +/- 0.09 nM) and their phagocytic ability markedly reduced (73 +/- 7.4 micrograms oil/10(7) PMNLs/min (normal: 153 +/- 3.8 micrograms oil/10(7) PMNLs/min). After 1 month of therapy, [Ca2+]i fell significantly (p < 0.01) to 53 +/- 1.0 nM with further decrement of a value of 40 +/- 0.9 nM by the end of 3 months of treatment. The levels of [Ca2+]i rose significantly (p < 0.01) to 61 +/- 2.1 nM after 1 month of cessation of therapy and were 69 +/- 2.5 nM by the end of 5 months; these values are not different from those observed before therapy. Phagocytosis improved significantly (p < 0.01) after 1 month of nifedipine therapy (107 +/- 3.9 micrograms oil/10(7) PMNLs/min) with no further improvement during the other 2 months of therapy. Only modest decrement in phagocytosis occurred during the first 3 months after cessation of nifedipine administration; marked and significant impairment (p < 0.01) in phagocytosis (80 +/- 2.6 micrograms oil/10(7) PMNLs/min) became evident at the end of the fifth month. The results show that (1) nifedipine treatment of HD patients rapidly reversed the elevation in [Ca2+]i of their PMNLs but discontinuation of the therapy is followed by rapid re-emergence of the elevation in the [Ca2+]i of the PMNLs; (2) nifedipine therapy causes rapid and significant, but only partial, improvement of phagocytosis, by PMNL of HD patients; almost 5 months is needed before a significant deterioration in phagocytosis becomes evident after stopping nifedipine treatment; (3) the elevation in [Ca2+]i of PMNLs of HD patients plays an important role in the pathogenesis of impaired phagocytosis but is only partially responsible for their derangement, and (4) the beneficial effect of nifedipine therapy on phagocytosis makes this drug a useful therapeutic tool to aid HD patients in their fight against infection.
Lack of suppression by ribavirin of HIV viraemia.
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Attitudes and experiences of human immunodeficiency virus-positive patients to surgery and surgeons.
The issues regarding screening and identification of patients at risk for human immunodeficiency virus (HIV) infection before surgery continue to be discussed, and there is a need for information regarding attitudes of both surgeons and patients to this issue. A population of HIV-positive patients attending a genitourinary medicine clinic were given an anonymous questionnaire to review their experiences of attending for operation. Of 174 patients who replied, 52 had undergone a total of 65 procedures. In all but three of the operations, the HIV status was made known to the surgeon.
Transmission of HIV-1 infection by oroanal intercourse.
We report the cases of two homosexual men, one of whom is believed to have been infected with HIV-1 during oroanal intercourse with the other, his only current sexual partner. Both patients had sero-conversion illnesses with similar symptoms and signs, and of similar duration. The practise of oroanal intercourse is known to be associated with the transmission of enteric infections and has been implicated in the epidemiology of Kaposi's sarcoma. These well-documented cases indicate that HIV-1 may also be transmitted by this route and supports a cautious approach to recommendations regarding "safer" sex.
T cell responses to peptides covering the gag p24 region of HIV-1 occur in HIV-1 seronegative individuals.
We demonstrate that peptides (16 amino acids long) covering the sequence of the HIV-1 core protein p24 induce significant proliferation in peripheral blood mononuclear cells (PBMC) of several (greater than 50%) healthy seronegative volunteers as well as seronegative homosexual men. The nature of this response was characterized and compared with those of HIV-infected patients. Several peptides induced responses; however, the most frequent responses in both seropositive and seronegative individuals were noted to the following peptides: 1 and 2 (aa 133-157); 6 and 7 (aa 183-207); 15 (aa 273-287); and 17 and 18 (aa 293-317). The response pattern was related to the disease stage of the patients; seronegative individuals as well as asymptomatic seropositive individuals (CDC II/III) responded to low concentrations of several peptides, but symptomatic patients (CDC IV) only responded to high concentrations of a few peptides. Cell separation studies of PBMC from healthy volunteers showed that the responding cells were CD4+ and expressed the CD45RO differentiation antigen. Furthermore, cord-blood mononuclear cells with less than 5% of CD45RO T cells did not proliferative to any of the peptides. Finally, CD4+ T cell lines specific for both peptides and p24 protein were successfully established from the PBMC of seronegative individuals confirming the data obtained with freshly isolated cells. These studies therefore suggest that the CD4+ cell response to p24 is not strictly disease related, instead, the response may be due to priming of the host with cross-reactive antigens.
No effect of zidovudine on hepatitis B virus replication in homosexual men with symptomatic HIV-1 infection.
Zidovudine triphosphate inhibits the hepatitis B virus (HBV) DNA polymerase (DNAp) in vitro. Serial measurements of serum HBV DNAp activity and HBV DNA were made in 14 consecutive male homosexual patients starting zidovudine for symptomatic HIV-1 infection. Median duration of treatment was 15 weeks (range 2-72). In the 13 patients with detectable DNAp/DNA pre-treatment, no significant change in either measure of viral replication was observed during the first 16 weeks of treatment compared with the 13 weeks prior to treatment. The lack of response may be due to the opposing effect of immunosuppression, or to a failure of in vivo activity.
Multiple prostatic abscesses presenting with urethral discharge.
Prostatic abscess has become less common, is now usually related to urinary tract infection, and is a rare cause of urethral discharge. The case is described of a man with prostatic abscesses caused by Staphylococcus aureus possibly related to recent skin abrasions. Transrectal ultrasound was used to make the diagnosis and to facilitate repeated drainage with a successful outcome.
Alcohol consumption--a risk factor for hemorrhagic and non-hemorrhagic stroke.
PURPOSE: The risks of alcohol consumption and its association with stroke were studied in 621 patients with stroke and 573 control subjects using case-control methods. PATIENTS AND METHODS: Patients with stroke were subdivided into 193 with subarachnoid hemorrhage, 91 with intracerebral hemorrhage, and 337 with cerebral infarction. Data on recent alcohol consumption were obtained by questionnaire in patients with stroke and compared with data from an occupational screening survey in control subjects. RESULTS: Relative risks, adjusted for confounding variables, exhibited J-shaped associations with increasing levels of alcohol consumption classified into four categories--abstainer, 1 to 90 g, 100 to 390 g, and greater than or equal to 400 g weekly). The individual risks were 1, 0.7, 0.5, and 1.3 for subarachnoid hemorrhage; 1.0, 0.6, 0.5., and 2.5 for intracerebral hemorrhage, and 1.0, 0.6, 0.7, and 2.4 for cerebral infarction for men and women combined. CONCLUSIONS: The results suggest that low levels of alcohol consumption may have some protective effect upon the cerebral vasculature, whereas heavy consumption predisposes to both hemorrhagic and non-hemorrhagic stroke.
Ganciclovir for lumbosacral polyradiculopathy in AIDS.
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Clinical aspects of HIV and AIDS.
The main messages from the Conference this year were that our management of opportunistic infections is improving with increasing therapeutic options available and better guidelines as to when to start treatment and prophylaxis. Since the first cases of the epidemic were reported in 1981 new drugs have been licensed, e.g. ganciclovir, fluxconazole and inhaled pentamidine. These have been developed, stimulated by the need for new agents to treat the increasing number of unusual infections. While the range of infections may not now be increasing so fast, the search for more effective, less toxic, agents continues.
Cigarette smoking. A risk factor for hemorrhagic and nonhemorrhagic stroke.
Cigarette smoking habit was studied in 621 patients with stroke and in 573 control subjects using case control methods. There was an excess of smokers among the stroke group when compared with control subjects. Relative risks of cigarette smokers compared with nonsmokers, after adjustment for the possible confounding variables for subarachnoid hemorrhage, intracerebral hemorrhage, and cerebral infarction, were 4.5, 1.8, and 3.2 for men and 2.5, 1.3, and 2.3 for women, respectively. For all subtypes of stroke combined, the increased relative risk was related to the daily intake of cigarettes, the heaviest smokers having a higher relative risk than that for light smokers. The estimated increase in relative risk among smokers was 1.5 for each 10 cigarettes smoked daily in both men and women. We conclude that cigarette smoke may be an important preventable factor for both hemorrhagic and nonhemorrhagic stroke.
Type-specific concordance in young diabetic monozygotic twins.
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Wind-chill and the seasonal variation of cerebrovascular disease.
The hospital admission rates for patients with specific types of stroke were examined for seasonal variation and correlation with meteorological factors. A seasonal variation in admission rates was found for subarachnoid haemorrhage, thrombo-embolic brain infarction and ill-defined cerebrovascular disease. Overall this seasonality was more strongly associated with the computed chilling effect of the atmosphere than with changes in temperature, humidity or wind speed alone. No seasonal variation was observed for admission rates of intracerebral haemorrhage, transient ischaemic attack or occlusion of precerebral arteries. Intracerebral haemorrhage admission rates exhibited a decrease with time. This evidence suggests that seasonal variation in admission rates exists only for certain pathological types of stroke and this is strongly associated with changes in the chilling effect of the atmosphere.
A community case-control study of alcohol consumption in stroke.
This study examines the hypothesis that there may be a clinically important association between alcohol intake and stroke. Alcohol consumption and the haematological and biochemical markers of alcohol intake were studied in hospital admissions for stroke and compared with community based control subjects from an occupational screening survey. In males, moderate to heavy alcohol consumption (greater than 30 units per week) was associated with an increased relative risk of stroke. Light drinking (less than 30 units per week) was associated with reduced relative risk when compared to teetotallers. The relative risk of stroke in moderate and heavy consumers of alcohol compared with teetotallers was elevated 1.8 times. Similar patterns of risk were present for increasing levels of aspartate transaminase and uric acid. Relative risk was increased for all levels of gamma-glutamyl transferase above the lowest. There was a decrease in relative risk associated with increasing levels of mean erythrocyte cell volume though this did not achieve statistical significance. There were few heavy drinkers among the female cases or controls. We conclude that high alcohol intake may be a significant preventable risk factor particularly among male strokes.
Long term mortality after a single treatment course with X-rays in patients treated for ankylosing spondylitis.
Mortality up to 1 January 1983 has been studied in 14,106 patients with ankylosing spondylitis given a single course of X-ray treatment during 1935-54. For neoplasms other than leukaemia or colon cancer, mortality was 28% greater than that of members of the general population of England and Wales, and this increase is likely to have been a direct consequence of the treatment. The proportional increase reached a maximum of 71% between 10.0 and 12.4 years after irradiation and then declined. There was only a 7% increase in mortality from these tumours more than 25.0 years after irradiation and only for cancer of the oesophagus was the relative risk significantly raised in this period. Neither the magnitude of the relative risk, nor its temporal pattern following treatment, were greatly influenced by the age of the patient at first treatment. For leukaemia there was a threefold increase in mortality that is also likely to have been due to the radiotherapy. The relative risk was at its highest between 2.5 and 4.9 years after the treatment and then declined, but the increase did not disappear completely, and the risk was still nearly twice that of the general population more than 25.0 years after treatment. There was some evidence that the risks of acute myeloid, acute lymphatic, and chronic myeloid leukaemia were all increased, but no evidence of any increase in chronic lymphatic leukaemia. The relative risk appeared to be greatest for acute myeloid leukaemia. For colon cancer, which is associated with spondylitis through a common association with ulcerative colitis, mortality was increased by 30%. For non-neoplastic conditions there was a 51% increase in mortality that was likely to be associated with the disease itself rather than its treatment. The increase was apparent for a wide range of diseases and was not confined to diseases that have been associated clinically with ankylosing spondylitis.