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Biomedical subjects

S M Hall

Publications and source records attributed to S M Hall.

At least 127 records · Page 7Linked to original sources
PubMed1990

Commitment to abstinence and acute stress in relapse to alcohol, opiates, and nicotine.

The effects of commitment to abstinence and acute stress on return to drug use were examined in a study of treated alcoholics, opiate users, and cigarette smokers (N = 221). Subjects were followed for 12 weeks or until they used their problem drug for 7 consecutive days. Commitment to absolute abstinence at end of treatment was related to a lower risk of returning to use and longer time between the first use and relapse. Withdrawal symptoms and negative and positive moods predicted first drug use, but only when assessed retrospectively. Prospective analyses failed to reveal a link between these variables and return to use. These findings suggest a reevaluation of current models of relapse. Acute stress may be less important in precipitating return to drug use than previously believed.

Adult↗
PubMed1990

In vitro and in vivo glucose consumption in swine eperythrozoonosis.

One complication of swine eperythrozoonosis is the hypoglycemia that occurs during parasitemia. To determine the cause of the hypoglycemia, we studied glucose consumption in splenectomized pigs infected with Eperythrozoon suis. With the rapid rise of erythroparasites, the in vitro glucose consumption of parasited whole blood increased dramatically, and hypoglycemia developed. Because mature porcine erythrocytes are impermeable to glucose, the increased glucose consumption is most logically the result of E. suis metabolism. Iodoacetamide and sodium fluoride (which inhibit glycolysis), but not sodium cyanide (which prevents cellular respiration), and tetracycline (which is used to treat eperythrozoonosis) inhibited glucose consumption. In vivo glucose turnover studies before infection and during peak parasitemia indicated an increased glucose production by infected pigs during parasitemia. The results suggest that hypoglycemia occurs during swine eperythrozoonosis because the parasite uses glucose faster than the gluconeogenic pathways can provide it.

Animals↗
PubMed1990

Haemolytic uraemic syndromes in the British Isles 1985-8: association with verocytotoxin producing Escherichia coli. Part 1: Clinical and epidemiological aspects.

A prospective study of the clinical and epidemiological features of the haemolytic uraemic syndromes was conducted over a three year period in the British Isles. Two hundred and ninety eight children were reported. In two thirds of cases stool samples were analysed for the presence of Verocytotoxin producing Escherichia coli (VTEC) and neutralisable Verocytotoxin. A total of 273 (95%) patients had a prodrome of diarrhoea. In these a seasonal variation in the incidence of haemolytic uraemic syndrome was demonstrated, the 1-2 year age range was most often affected, and the peripheral blood neutrophil count correlated positively with an adverse outcome. Patients presenting without diarrhoea showed none of these associations and had a significantly greater morbidity and mortality. Evidence for VTEC infection was found in 58 (33%) of 178 diarrhoea associated cases whose stools were analysed, although VTEC were identified in five of eight (62%) patients whose stools were collected within three days of the onset of diarrhoea. Most isolates produced VT2 either alone, or together with VT1. There was no evidence of VTEC infection in patients without prodromal diarrhoea.

Bacterial Toxins↗
PubMed1990

Trends in the incidence of Reye's syndrome and the use of aspirin.

In 1986 there was a public warning in the United Kingdom about a link between the consumption of aspirin and Reye's syndrome. To find out if the use of aspirin and paracetamol in children had altered, and whether the incidence of Reye's syndrome had changed since a previous study, parents were interviewed in Belfast and London, and the British Reye's Syndrome Surveillance System data were reviewed. Children with febrile illnesses were 17 times more likely to have received aspirin before admission to hospital in 1985/6 compared with 1988/9. Only 21 Belfast parents (40%) and 13 London parents (27%) had heard of Reye's syndrome and only 12 in Belfast (23%) and seven in London (15%) knew of its association with aspirin, suggesting a continuing need for public education. Cases of Reye's syndrome declined both in numbers (from a peak of 79 in 1983/4 to 19 in 1988/9) and in median age. Of the 418 reported cases, the diagnosis was subsequently revised in 89, most often (in 31 of 89, 36%) to 'inborn errors of metabolism'.

Acetaminophen↗
PubMed1990

Recombinant DNA probe detecting Eperythrozoon suis in swine blood.

A genomic library to Eperythrozoon suis DNA was constructed in lambda gt11, and from this library, E suis clone KSU-2 was identified as a potential diagnostic probe. In hybridization experiments that used 100-microliters samples of blood collected in chaotropic salt solutions, the KSU-2 probe hybridized strongly with purified E suis organisms and blood samples from splenectomized swine that were parasitized with E suis. However, the probe under stringent conditions did not give radiographic indications of hybridizing with equine blood DNA, bovine blood DNA infected with Anaplasma marginale, canine blood DNA infected with Ehrlichia canis, feline blood DNA infected with Haemobartonella felis, or uninfected swine blood DNA.

Animals↗
PubMed1989

Changes in food intake and activity after quitting smoking.

Quitting smoking often results in weight gain. The causes of the gain are not known. The present study evaluated changes in calories, total sugars, sucrose, fat, protein, and nonsugar carbohydrates as well as changes in activity levels after quitting smoking. Ninety-five subjects were randomly assigned to either early (Week 2) or late (Week 6) quit dates. Subjects were assessed on weight, food intake, activity levels, and smoking levels at baseline, at Weeks 4 and 8, and at Weeks 12 and 26 postquit. The results indicated significant increases in calories, sucrose, and fats 2 weeks after the quit date. Changes for total sugars were less consistent. Activity levels did not change significantly. Early caloric increases predicted weight gain at 26 weeks for abstinent women. No relation was found for abstinent men, but interpretation of this finding is weakened by a small subsample size. Abstinent subjects gained over 9 lb by 26 weeks postquit. Despite this gain, Week 26 results showed that caloric intake for abstinent women was approximately equal to that observed at baseline, whereas that for abstinent men had dropped significantly.

Adult↗
PubMed1989

Brucella abortus-specific immunoglobulin isotypes in serum and vaginal mucus from heifers vaccinated with Brucella abortus salt-extractable proteins and challenge exposed with virulent Brucella organisms.

Serum and vaginal Brucella-specific immunoglobulin isotypes (IgG1, IgG2, IgM, and IgA), obtained from 62 crossbred beef heifers vaccinated with Brucella abortus salt-extractable proteins and subsequently challenge exposed with B abortus S2308, were studied. Brucella-specific IgG antibodies and Brucella-specific immunoglobulin isotypes were quantitated by a fluorometric immunoassay. Serum and vaginal immunoglobulin responses were evaluated as a method of distinguishing infected from noninfected heifers. Rivanol precipitation, complement-fixation, buffered-antigen brucellosis tests and an ELISA were performed on sera. For immunoglobulin isotypes, vaccinated heifers had mean antibody responses higher than baseline mean antibody responses for at least 31 weeks after vaccination. After challenge exposure, significant differences (P greater than 0.05) were not detected between mean antibody responses of vaccinated and nonvaccinated heifers. Vaginal Brucella-specific antibody responses did not correlate with protection from disease. Vaginal Brucella-specific IgM was detected only at the time of abortion. Vaginal IgA appeared specific for identification of virulent B abortus infection. All serotests appeared adequate in distinguishing baseline titers from titers of heifers that had aborted and were considered bacteriologic culture-positive. Results of serotests neither consistently distinguished vaccinates from challenge-exposed cattle nor distinguished heifers that were challenge exposed, had aborted, and were considered bacteriologic culture-positive adequately from heifers that were challenge-exposed, had not aborted, and were considered bacteriologic culture-negative. Brucella-specific IgA appeared to be the most effective in distinguishing vaccinated heifers from challenge- exposed heifers and heifers that were challenge exposed and had aborted, from heifers that were challenge exposed and had not aborted. Brucella-specific serum IgA was detected up to 13 weeks after abortion.

Animals↗
PubMed1988

Early detection of visual defects in infancy.

To determine the part played by screening in detecting visual defects questionnaires were sent to 240 families with blind or partially sighted children identified from the Family Fund's database. Questions were asked on social and family background, the visual disorder and its severity, any other disability, and how and when the disabilities were discovered and subsequently managed. Data from 189 families were analysed, constituting all those with children with major visual defects from the 219 families who replied. The visual defect was first discovered in 111 children by parents, friends, and neighbours, and in 36 by a doctor at the neonatal examination. In only three children who did not have a family history of visual impairment was the defect discovered during a formal screening examination at a child health clinic. Dissatisfaction about medical services was expressed by about a third of the parents, particularly a lack of provision of information and consideration of their worries and a failure to refer the child promptly to educational and treatment services. Visual defects in children under 5 are generally detected by family and friends, not by screening, but detection by the medical profession could be improved by increased awareness and observation and quick referral.

Child, Preschool↗
PubMed1988

Peripheral demyelination and remyelination initiated by the calcium-selective ionophore ionomycin: in vivo observations.

Incubation of nerve with Ca2+ and the divalent cation ionophores A23187 or ionomycin, causes a prompt vesiculation of the myelin at the paranodes and Schmidt-Lanterman incisures. The vesiculation appears to be dependent upon a rise in the intracellular calcium concentration of the affected Schwann cells. To determine whether a similar vesiculation might occur in vivo, and to examine the long term consequences of ionophore exposure, the sciatic nerves of rats and mice were injected with ionomycin and examined histologically after intervals of 1 h to 75 days. A prompt myelin vesiculation was again observed, and this spread from the paranodes and incisures to invade regions of formerly compact myelin: segmentally demyelinated axons were common 7 days post-injection. The lesions were large, and involved up to 95% of the fibres in the mouse. There was little evidence of either Schwann cell necrosis, or axonal degeneration in either species. The appearance and spatio-temporal progression of the lesion was strikingly similar to that seen after the intraneural injection of lysophosphatidylcholine or phospholipase A2. However, in the ionophore lesion, not all the demyelination was effected by myelin vesiculation, for up to 30% of the affected fibres showed evidence of macrophage-mediated stripping. Macrophage stripping was confined to internodes already affected by vesiculation. Most of the myelin debris was removed by macrophages, and myelin debris was only rarely observed within Schwann cells. Remyelination was initiated in nearly all the affected fibres by 21 days, and by 2 months all affected fibres were invested with thin, new myelin sheaths. These findings may be relevant to immune-mediated demyelination in the peripheral nervous system.

Animals↗