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Biomedical subjects

B Thomas

Publications and source records attributed to B Thomas.

At least 145 records · Page 8Linked to original sources
PubMed1993

Epidemiology of Alzheimer's presenile dementia in Scotland, 1974-88.

OBJECTIVE: To describe the epidemiology of presenile Alzheimer's disease in Scotland from 1974 to 1988. DESIGN: Retrospective review of hospital records of patients aged less than 73 years admitted to psychiatric hospital with various diagnoses of dementia. Diagnoses were classified by National Institute for Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association Criteria and the Hachinski score. Completeness of the study sample was evaluated by scrutiny of neurology outpatient and general hospital records. SETTING: All general psychiatric hospitals in Scotland. SUBJECTS: All patients with onset of dementia aged 40-64. MAIN OUTCOME MEASURES: Probable and broad Alzheimer's disease, sex of patient, age at onset. RESULTS: 5874 psychiatric hospital records, 129 neurology outpatient records, and 89 records from non-psychiatric hospitals were examined. 317 patients met criteria for probable Alzheimer's disease, 569 met criteria for broad Alzheimer's disease, and 267 met those for multi-infarct dementia. Minimal incidences per 100,000 population aged 40-64 years were 22.6 (95% confidence interval, 20.2 to 25.2) and 40.5 (38.9 to 42.3) per 100,000 for probable and broad Alzheimer's disease. In the 1981 census year the annual incidence of probable Alzheimer's disease was 1.6 (1.0 to 2.6). Women were at greater risk with incidence rates for probable Alzheimer's disease of 28.2 (24.5 to 32.4) per 100,000 compared with 16.5 (13.8 to 19.8) per 100,000 for men. The incidence per 100,000 for multi-infarct dementia was greater in men (25.1, 23.3 to 27.1) than women (13.4, 12.1 to 14.8). CONCLUSION: Female sex seems to be positively associated with development of Alzheimer's disease before age 65 years.

Adult↗
PubMed1993

Survival and predictors of death in dialysed diabetic patients.

The objective of this study was to examine diabetic patients at the time of admission to maintenance haemodialysis and to follow them for 36 months in order to define predictors of cardiovascular and non-cardiovascular death. This prospective study comprised all consecutive diabetic patients admitted to 28 German dialysis centres between January 1985 and October 1987; 196 patients were examined, 67 Type 1 (insulin-dependent) diabetic (43 male, 24 female; median age 49 years, range 22-73) and 129 Type 2 (non-insulin-dependent) diabetic patients (54 male, 75 female; 64 years, range 37-82). Outcome measures were death, i.e. myocardial infarction, sudden death, cardiac death of other causes, stroke and non-cardiovascular death. Actuarial survival 36 months after the beginning of dialysis was similar in Type 1 (40%) and Type 2 diabetic patients (43%) despite the age difference. Causes of death were myocardial infarction (18%), sudden death (18%), other cardiac causes (18%); stroke (6%); septicaemia (17%) mostly originating from diabetic foot problems; and interruption of therapy. Survival rates and the proportion dying from cardiac causes were similar in patients with diabetic nephropathy or with other primary chronic renal disease and coincidental diabetes. On dialysis, de novo amaurosis or de novo amputation was not observed in any patient. The strongest predictor of myocardial infarction or sudden death was serum lipids on admission. Duration of hypertension, blood pressure at the time of admission to dialysis, left ventricular hypertrophy or end-diastolic diameter by echocardiography, Sokolow index and average predialysis blood pressure, smoking, interdialytic weight gain and type of dialysis were not predictive of cardiovascular death or death by all causes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Decreased sensitivity of aorta from hypertensive rats to vasorelaxation by tyrphostin.

The role of protein tyrosine kinases (PTKs) in vascular smooth muscle (VSM) contraction was examined in spontaneously hypertensive rats (SHRs). Aorta from SHRs was hyperresponsive to PTK-mediated contraction relative to normotensive Wistar-Kyoto rats (WKYs). Aorta from SHR was also hyporesponsive to vasorelaxation by tyrphostin, a selective inhibitor of PTKs. Further, we found alterations in PTK activity in aorta from SHRs. PDGF stimulated PTK activity to a greater extent in the SHR. Tyrphostin inhibited PDGF-induced PTK stimulation in both strains, however, activity returned to basal levels in the WKY only. The results suggest that PTKs may be involved in VSM contraction and in the development of hypertension.

Animals↗
PubMed1993

Growing up with Patricia.

Parents of a child with special needs to describe their experiences coping with the various challenges to the family as they grew up together. They discuss coping strategies, shared responsibility, and the trials of dealing with physicians, schools, and social service agencies. They talk about advocating for their child and preparing for the transition to adulthood. Their story is followed by a commentary by a social worker who suggests techniques that pediatricians can use to empower families of children with disabilities to optimize outcome.

Child↗
PubMed1993

Serum lipids predict cardiac death in diabetic patients on maintenance hemodialysis. Results of a prospective study. The German Study Group Diabetes and Uremia.

The objective of this study was to measure cholesterol concentrations in diabetic patients at the beginning of maintenance hemodialysis treatment and to define their role as predictors of subsequent cardiac death on maintenance hemodialysis. The design of this study consisted of a prospective study of all consecutive diabetic patients newly admitted to 28 German dialysis centers between January 1985 and October 1987. The patients were examined on admission and subsequently followed for 45 months on dialysis. This study included 196 patients, 67 type I (43 male, 24 female, median age 49 years, range 22-73) and 129 type II (54 male, 75 female, aged 64 years, range 37-82). Lipids (total cholesterol, triglycerides low-density lipoprotein (LDL) cholesterol high-density lipoprotein (HDL) cholesterol apolipoprotein B and A and anthropometric indices (body mass index, triceps skinfold thickness) were measured. The outcome was death, i.e., cardiovascular (myocardial infarction, sudden death, other cardiac causes, stroke) and noncardiovascular death during a 45-month follow-up. At the start of treatment, total cholesterol, triglycerides LDL cholesterol, LDL/HDL ratio and apolipoprotein B were significantly higher in diabetics than in healthy controls or patients with standard primary renal disease starting dialysis. Only minor differences were found between males and females and type I and type II diabetics. Fourty-three percent of type I and 50% of type II diabetics died, 61% from cardiovascular causes, mostly myocardial infarction (in 40% reinfarction) and sudden death. On admission, diabetics subsequently dying from myocardial infarction had significantly higher median cholesterol than survivors, i.e., 259 versus 222 mg/dl, and higher LDL cholesterol, LDL/HDL ratio and apolipoprotein B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Tyrphostin attenuates platelet-derived growth factor-induced contraction in aortic smooth muscle through inhibition of protein tyrosine kinase(s).

The effect of protein tyrosine kinase (PTK) inhibition on spontaneously hypertensive rat vascular smooth muscle contraction was examined in this study. By using isolated aortic strips, it was found that platelet-derived growth factor (PDGF) (0.1-1 nM), an activator of PTKs, elicited contraction with an EC50 of 0.25 +/- 0.08 nM. Treatment with tyrphostin (0.02-200 microM), a selective inhibitor of PTKs, caused a significant rightward shift of the concentration-response curves (P < .05). The IC50 for tyrphostin in the spontaneously hypertensive rat was calculated to be 9.5 +/- 4.2 microM. Tyrphostin also inhibited contractile activity in normotensive control Wistar-Kyoto rat aorta with an IC50 of 0.24 +/- 0.09 microM. Tyrphostin inhibited PDGF-induced contraction over a range of calcium concentrations, suggesting that it may oppose contraction through inhibition of calcium influx via PDGF-induced receptor-operated channel. However, KCl-mediated voltage-operated calcium channels were largely unaffected by tyrphostin, because it was unable to relax aortae which had been partially depolarized. Tyrphostin also had no significant antagonistic effect on contraction induced by phenylephrine or phorbol-12,13-dibutyrate. For both of these agents, contraction is mediated through activation of protein kinase C, which further alludes to the specificity of tyrphostin for PTKs. Treatment with 1 nM PDGF caused a significant stimulation of particulate/membrane PTK activity in the aorta. Tyrphostin attenuated PDGF-induced PTK activity in a concentration-dependent manner. The data suggest that PTKs may play a role in vascular smooth muscle contraction and that specific inhibition of PTK activity results in vasorelaxation. Furthermore, the results suggest that vasoconstriction and vascular smooth muscle cell proliferation may share common biochemical signalling pathways.

Animals↗
PubMed1992

Protein Differences between Two Isogenic Cultivars of Barley (Hordeum vulgare L.) that Differ in Sensitivity to Photoperiod and Far-Red Light.

A photoperiodically sensitive cultivar of barley (Hordeum vulgare L. Shabet) (BMDR-8) and an isogenic, single-gene recessive mutant of this genotype that is insensitive to photoperiod (BMDR-1) were grown under continuous cool white light with or without supplemental far-red fluorescent light. BMDR-1 initiates flowers 6 days after germination, irrespective of light treatment, whereas BMDR-8 remains vegetative for at least a week longer, even in continuous light. When far-red light is added, the delay of flowering in BMDR-8 is overcome and both genotypes initiate floral primordia at the same time. Total phenol extracted proteins of seedlings of both genotypes were resolved by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No protein differences were found between the genotypes when isoelectric focusing gels were run in the first dimension. Two qualitative genotypic differences were found when nonequilibrium pH gradient gel electrophoresis was run in the first dimension. An 85-kilodalton polypeptide (A) and a 26-kilodalton polypeptide (B) were always present in BMDR-8 but never found in BMDR-1. The levels of A appeared to decrease from the BMDR-8 during the first 3 days of far-red treatment but did not disappear completely even after 6 days of growth in the presence of farred. Polypeptide B decreases rapidly in continuous cool white light but is stabilized by far-red. The phytochrome content of BMDR-1 was found to be greater than that for BMDR-8. This increase appears to be caused by the type I (etiolated-tissue abundant) phytochrome pool, even in plants grown in continuous light.

Journal Article↗
PubMed1992

Evidence that recBC-dependent degradation of duplex DNA in Escherichia coli recD mutants involves DNA unwinding.

Infection of Escherichia coli with phage T4 gene 2am was used to transport 3H-labeled linear duplex DNA into cells to follow its degradation in relation to the cellular genotype. In wild-type cells, 49% of the DNA was made acid soluble within 60 min; in recB or recC cells, only about 5% of the DNA was made acid soluble. Remarkably, in recD cells about 25% of the DNA was rendered acid soluble. The DNA degradation in recD cells depended on intact recB and recC genes. The degradation in recD cells was largely decreased by mutations in recJ (which eliminates the 5' single-strand-specific exonuclease coded by this gene) or xonA (which abolishes the 3' single-strand-specific exonuclease I). In a recD recJ xonA triple mutant, the degradation of linear duplex DNA was roughly at the level of a recB mutant. Results similar to those with the set of recD strains were also obtained with a recC++ mutant (in which the RecD protein is intact but does not function) and its recJ, xonA, and recJ xonA derivatives. The observations provide evidence for a recBC-dependent DNA-unwinding activity that renders unwound DNA susceptible to exonucleolytic degradation. It is proposed that the DNA-unwinding activity causes the efficient recombination, DNA repair, and SOS induction (after application of nalidixic acid) in recD mutants. The RecBC helicase indirectly detected here may have a central function in Chi-dependent recombination and in the recombinational repair of double-strand breaks by the RecBCD pathway.

DNA Helicases↗
PubMed1992

Accuracy and completeness of Scottish mental hospital in-patient data.

In Scotland the Information and Statistics Division of the Scottish Office Home and Health Department maintains a computerised record of patients who have been admitted to, discharged from or have died in Scottish mental hospitals. This data source is of particular value to those involved in planning health care provision and to epidemiologists. The present study assesses the quality of these data in relation to patients with verified presenile dementia who have been discharged from the Royal Edinburgh Hospital between 1974 and 1988. Seventeen per cent of presenile patients were not identified and 23% of patients were wrongly classified. More than 93% of patients with presenile Alzheimer's disease were identified, though often under a variety of other diagnostic codes. These findings highlight limitations of the data supplied and suggest that the usefulness of this enviable and unique data source could be enhanced if the medical profession took greater care in clearly stating an International Classification of Diseases diagnosis in a patient's hospital record.

Data Collection↗
PubMed1991

Detection of Chlamydia trachomatis by direct immunofluorescence improved by centrifugation of specimens.

During a study of women with laparoscopically investigated pelvic pain, genital tract specimens were examined for Chlamydia trachomatis using a direct fluorescent antibody (DFA) technique (MicroTrak, Syva) and culture. Some smears, particularly those from the upper genital tract, contained an inadequate number of cells when examined by the DFA technique and many cell monolayers were destroyed by the specimens. To obtain results for such samples, or to confirm the original DFA result, additional specimens which had been frozen at -70 degrees C or in liquid nitrogen were centrifuged at high speed and the resulting deposit examined by the DFA technique. By this means, 32 negative results were confirmed for specimens from 10 chlamydia-negative patients with pelvic inflammatory disease or with high chlamydial antibody titres, and 26 negative results were confirmed for 19 patients who were positive at other sites. In addition, three chlamydia-positive and six chlamydia-negative results were obtained for sites where the original smear for DFA testing had been inadequate (few epithelial cells) and six specimens that were negative originally were found to be positive. Thus, of 73 specimens that were either inadequate or negative by DFA testing originally, 9 (12%) were positive by DFA testing after centrifugation.

Centrifugation↗