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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 505 records · Page 28Linked to original sources
PubMed1995

Vertical loading rates in clinically normal dogs at a trot.

Present data describe the rates of vertical loading and unloading generated by clinically normal dogs in a trotting gait. Forward velocity was found to influence maximal rates of limb loading and unloading in forelimbs and hind limbs. The rates increased as the velocity of the dog/handler increased. The position of maximal limb loading during the stance phase was independent of velocity in the forelimbs, but in the hind limbs, as velocity increased, the position of maximal unloading occurred earlier in the stance phase. Within velocity groups, the forelimbs had greater rates of vertical loading and unloading than did hind limbs. The position at which maximal loading occurred was earlier in the forelimbs than in the hind limbs. There was a difference in the position of maximal unloading between forelimbs and hind limbs, with the forelimbs unloading earlier in the stance phase. Difference between paired forelimbs or paired hind limbs was not found for any measurement within any group. Calculation of loading and unloading rates provides another method of examining functional limb loading in dogs. This method of analysis can be adapted to any animal gaited across a force platform in which single limb strides can be recorded. Calculations can also be done in any axis of measurement. Data indicated loading and unloading rates to be consistent and easily determined, Use of data generated from rates of limb loading can be classified into 2 areas: documentation of acceptance of load by the limb, and indirect measurement of functional stresses placed on bones of the appendicular skeleton.

Animals↗
PubMed1994

Bovril and moclobemide: a novel therapeutic strategy for central autonomic failure.

The consumption of tyramine-containing foods is contraindicated in patients on classic monoamine oxidase (MAO) inhibitors. We report successful therapeutic use of moclobemide (a MAO-A selective inhibitor) plus controlled amounts of Bovril (a tyramine-rich yeast-extract available as a food) in a patient with pure central autonomic failure who was rendered bed-bound by severe postural hypotension. Standing blood pressure is now at least 90/45 mm Hg. The selectivity of moclobemide allows about a tenth of ingested tyramine to reach nerve endings and thus the modest hypertensive effect of this combination re-established day-to-day function by restoring normotension.

Activities of Daily Living↗
PubMed1994

Intercultural consultations: investigation of factors that deter non-English speaking women from attending their general practitioners for cervical screening.

OBJECTIVES: To determine the factors that deter ethnic minority women living in east London from attending their general practitioner for cervical cytology screening. DESIGN: Qualitative study by means of focus group discussions between October 1993 and March 1994. SETTING: East London. SUBJECTS: Non-health specific established community groups and specially convened groups of Bengali, Kurdish, Turkish, Urdu and Punjabi, and Chinese speaking women. MAIN OUTCOME MEASURES: The spontaneous views of non-English speaking women resident in east London on cervical screening, focusing on attitudes to screening, their experiences of the cervical cytology screening services as currently provided, and their knowledge and beliefs about cervical screening. RESULTS: Some reported attitudinal barriers to cervical cytology screening such as fear of cancer were not deterrents. Administrative and language barriers were more important, as were inadequate surgery premises and concerns about sterility. CONCLUSION: Contrary to popular belief among general practitioners in east London, women from ethnic minorities are enthusiastic about cervical cytology screening once they understand the purpose of the test and the call and recall procedures. It is possible to consult with community groups in their own language through focus group discussions, working with bilingual health advocates who have had a short practical training in facilitating small group discussions. This form of user consultation could be carried out focusing on other aspects of health promotion.

Asia↗
PubMed1994

Mental retardation and Ullrich-Turner syndrome in cases with 45,X/46X,+mar: additional support for the loss of the X-inactivation center hypothesis.

Four cases having mosaicism for a small marker or ring [45,X/46,X,+mar or 45,X/46,X,+r] chromosome were ascertained following cytogenetic studies requested because of minor anomalies (cases 1, 3, and 4) and/or short stature (cases 2 and 4). While all 4 cases had traits typical of Ullrich-Turner syndrome (UTS), cases 1, 3, and 4 had manifestations not usually present in UTS, including unusual facial appearance, mental retardation/developmental delay (MR/DD) (cases 3 and 4), and syndactylies (case 1). The facial appearances of cases 1 and 3 were similar yet distinct from that of case 4. Using fluorescence in situ hybridization (FISH), each of the markers in these 4 cases was identified as having been derived from an X chromosome. The level of mosaicism for the mar/r(X) cell line in these cases varied from 70% (case 1) to 16% (case 4) but was not apparently correlated with the presence of MR/DD. Replication studies demonstrated a probable early replication pattern for the mar/r(X) in cases 1, 3, and 4, while the marker in case 2 was apparently late replicating. To date, 41 individuals having mosaicism for a small mar/r(X) chromosome have been described. Interestingly, most of the 14 individuals having a presumedly active mar/r(X) demonstrated clinical findings atypical of UTS, including abnormal facial changes (11) and MR/DD (13). MR was noted most frequently in those cases having at least 50% mosaicism for the marker or ring. In contrast, atypical UTS facial appearance or MR/DD was not noted in 14 of the 16 cases with UTS who carried a probable late replicating marker or ring. In conclusion, although the phenotype of 45,X/46,X,mar/r(X) individuals appears to be influenced by the genetic content and degree of mosaicism for the mar/r(X), the most significant factor associated with MR/DD appears to be the activity status of the mar/r(X) chromosome. Thus, our 4 cases provide further support for the hypothesis that a lack of inactivation of a small mar/r(X) chromosome may be a factor leading to the MR and other phenotypic abnormalities seen in this subset of individuals having atypical UTS.

Child↗
PubMed1994

The type A/type B distinction. Subtyping alcoholics according to indicators of vulnerability and severity.

Multidimensional typologies of alcoholics are reviewed, including Cloninger's neurobiological learning model, Morey and Skinner's hybrid model, and Zucker's developmental model. The more recent Type A/Type B typology proposed by Babor and colleagues is reviewed in more depth, as is a previous replication and extension by Litt and colleagues. Both the original study and the replication indicate this typology is a useful tool in classifying alcoholic inpatients into two groups and in matching alcoholics to the most suitable treatment. The present study replicates the typology using outpatient samples of male alcoholics. The resulting two clusters are very similar to those identified by the two earlier studies. As expected, the relative proportion of Type A alcoholics is higher in the outpatient samples than in the previously studied inpatient samples. Preliminary analysis of the typology's clinical efficiency suggests that the variables used to classify subjects might be appreciably reduced, thus effecting a considerable time savings in assessment. A discriminant function analysis indicates that using only 5 of the original 16 clustering variables results in a correct classification rate of almost 95%. Future research directions are addressed.

Adult↗
PubMed1994

Evaluation of a new cytotoxicity assay for Clostridium perfringens type D epsilon toxin.

A new cytotoxicity assay for determining the activity of epsilon toxin produced by Clostridium perfringens type D has been developed. Viability of cultured cells was determined by the ability of only live cells to convert 5-(3-carboxymethoxyphenyl)-2-(4,5-dimethylthiazolyl)-3-(4- sulfophenyl)tetrazolium to the coloured product formazan in the presence of phenazine methosulfate. Of the 12 cell lines tested, only the MDCK cell line was susceptible to epsilon toxin. Specificity was confirmed by the ability of only specific monoclonal antibodies to inhibit cytotoxicity. Good correlation was obtained with the mouse lethality assay (r = 0.991) and over a wide range of viability (15-75%) as determined by ethidium bromide/acridine orange staining (r = 0.995).

Animals↗
PubMed1994

Buspirone treatment of anxious alcoholics. A placebo-controlled trial.

BACKGROUND: Symptoms of anxiety are common in alcoholics and may contribute to relapse following initiation of abstinence. Buspirone hydrochloride, a serotonin1A partial agonist, has a pharmacologic profile that may be particularly suited to the treatment of anxious alcoholics. METHODS: We conducted a randomized, 12-week, placebo-controlled trial of buspirone in 61 anxious alcoholics, all of whom also received weekly relapse prevention psychotherapy. Outcomes were measured at the end of treatment and at a 6-month follow-up evaluation. RESULTS: Buspirone therapy was associated with greater retention in the 12-week treatment trial, reduced anxiety, a slower return to heavy alcohol consumption, and fewer drinking days during the follow-up period. CONCLUSIONS: Buspirone appears to have a useful role in the treatment of anxious alcoholics. Further research is needed to clarify which patient characteristics and concomitant treatments result in optimal response to buspirone therapy.

Adult↗
PubMed1994

Linkage analysis of the genetic determinants of high density lipoprotein concentrations and composition: evidence for involvement of the apolipoprotein A-II and cholesteryl ester transfer protein loci.

We have tested for evidence of linkage between the genetic loci determining concentrations and composition of plasma high density lipoproteins (HDL) with the genes for the major apolipoproteins and enzymes participating in lipoprotein metabolism. These genes include those encoding various apolipoproteins (apo), including apoA-I, apoA-II, apoA-IV, apoB, apoC-I, apoC-II, apoC-III, apoE, and apo(a), cholesteryl ester transfer protein (CETP), HDL-binding protein, lipoprotein lipase, and the low density lipoprotein (LDL) receptor. Polymorphisms of these genes, and nearby highly polymorphic simple sequence repeat markers, were examined by quantitative sib-pair linkage analysis in 30 coronary artery disease families consisting of a total of 366 individuals. Evidence for linkage was observed between a marker locus D16S313 linked to the CETP locus and a locus determining plasma HDL-cholesterol concentration (P = 0.002), and the genetic locus for apoA-II and a locus determining the levels of the major apolipoproteins of HDL, apoA-I and apoA-II (P = 0.009 and 0.02, respectively). HDL level was also influenced by the variation at the apo(a) locus on chromosome 6 (P = 0.02). Thus, these data indicate the simultaneous involvement of at least two different genetic loci in the determination of the levels of HDL and its associated lipoproteins.

Apolipoprotein A-II↗
PubMed1994

Motivation: cause or confound in information processing/intelligence correlations?

The goal of the present study was to determine whether correlations between information processing scores and intelligence can be explained in terms of between-subject motivational differences. One hundred and nine male and female volunteer college students were tested on a battery of microcomputerized cognitive tests. One hundred of these subjects returned for a second session in which they were randomly assigned to an incentive or no-incentive condition and then retested. The effort expended on the tests was measured via heart rate, skin conductance, and a self-report questionnaire. Criterion measures, including the Advanced Otis-Lennon Test of Mental Abilities and Advanced Raven Progressive Matrices were also taken. The findings revealed that incentives had relatively modest effects on performance. In no case, however, did incentives affect the overall IQ-performance correlation for the tests used in the battery. These results support the view that correlations between information processing scores and intelligence reflect common mental capacities, rather than some affective variable such as motivation.

Adolescent↗
PubMed1994

Hypothalamic concentration and release of neuropeptide Y into microdialysates is reduced in anorectic tumor-bearing rats.

Hypothalamic concentration of neuropeptide Y was decreased significantly in anorectic tumor-bearing rats, while NPY level was increased significantly in matched carcass weight control rats as compared with freely-feeding controls. In vivo microdialysis of the perifornical hypothalamic area of tumor-bearing rats prior to the development of anorexia revealed no alteration in NPY in dialysates. Following the development of anorexia, however, tumor-bearing rats exhibited significant reduction in NPY concentration in dialysates as compared with either matched carcass weight or freely-feeding control group. These results suggest that hypothalamic NPY concentration and release are decreased selectively in anorectic tumor-bearing rats. Since NPY also elicits less feeding in tumor-bearing rats, dysfunction of hypothalamic NPY feeding mechanisms may be of primary importance in cancer anorexia.

Animals↗
PubMed1994

Dihydropyridine-sensitive calcium channels and barbiturate tolerance and withdrawal.

We have shown previously that the dihydropyridine calcium channel antagonist nitrendipine, given chronically, prevents the development of ethanol tolerance and physical dependence. The present study examines the effects on barbiturate tolerance and physical dependence. Nitrendipine, given acutely during withdrawal, provided little protection against barbiturate withdrawal, as measured by convulsive behaviour on handling. When nitrendipine was given chronically concurrently with the barbiturate, a prolonged protection against the withdrawal syndrome was seen. Acute nitrendipine significantly increased the latency of seizures in response to the partial benzodiazepine inverse agonist FG7142 during barbiturate withdrawal, but there was no effect on the seizure incidence in response to bicuculline. Chronic treatment with nitrendipine did not alter the development of tolerance to the ataxic or general anaesthetic actions of barbiturates, but evidence was found of a possible interaction between nitrendipine and pentobarbitone, which may have been pharmacokinetic. The results suggest that neuronal calcium channels may be involved to some degree in the development of the changes responsible for barbiturate withdrawal, but to a less extent than found previously for ethanol dependence.

Anesthesia, General↗
PubMed1994

Effects of long-term use of high-dose inhaled steroids on bone density and calcium metabolism.

BACKGROUND: Inhaled steroids are the mainstay in the antiinflammatory treatment of asthma. In the last few years, these agents have been used in increasing doses. Because high doses of inhaled steroids can reduce serum osteocalcin levels, there are concerns regarding their long-term effects on bone metabolism. METHODS: We examined the effects of doses of 800 micrograms/day or greater of beclomethasone or budesonide for more than 18 months in 37 asthmatic subjects (group A), matched to a control group of 37 asthmatic subjects using little or no inhaled steroids (< 500 micrograms, group B). All had a clinical evaluation, measurements of expiratory flows, and determination of serum creatinine, calcium, phosphate, gamma-glutamyl transpeptidase, alkaline phosphatase, cortisol, and osteocalcin levels. A 2-hour urinary sample was obtained for creatinine, calcium, phosphate, hydroxyproline, and cortisol measurements. Bone density was assessed at the lumbar spine level and at the hip with a Hologic-QDR-2000 osteodensitometer (Hologic, Boston, Mass.). RESULTS: The mean (+/- SD) daily dose of inhaled steroids over the last 2 years was 1140 +/- 353 micrograms in group A (mean duration of use of > 800 micrograms/day, 34.2 +/- 13.0 months) and 89 +/- 98 micrograms for group B (mean duration of use of < 500 micrograms/day, 15.7 +/- 18.8 months). The number of oral steroid treatments (< 15 days) during the last 2 years was small in the two groups, 0.92 +/- 1.27 in group A and 0.05 +/- 0.23 in group B (p > 0.05). The only differences between our two groups in terms of serum or urinary parameters were for mean osteocalcin level, which was lower in group A (2.16 +/- 1.09 ng/ml) than in group B (2.70 +/- 0.98 ng/ml) (p = 0.029), and in mean urinary phosphorous level, which was higher in group A (1.44 +/- 0.76 mmol/2 hr) than in group B (1.26 +/- 0.89 mmol/2 hr (p = 0.034). Mean urinary hydroxyproline levels were 15.51 +/- 6.98 mumol/2 hr in group A and 13.53 +/- 7.13 mumol/2 hr in group B (p > 0.05). Mean mineral bone densities of the lumbar spine and hip were similar in the two groups with values of 0.923 +/- 0.136 gm/cm2 and 0.719 +/- 0.147 gm/cm2 in group A and 0.933 +/- 0.154 gm/cm2 and 0.694 +/- 0.095 gm/cm2 in group B (p > 0.05). The T and Z scores for lumbar spine were -1.32 +/- 1.22 and -0.85 +/- 1.02 in group A and -1.19 +/- 1.33 and -0.72 +/- 1.08 in group B (p > 0.05). There was no correlation between the duration or dose of steroid use and bone density or osteocalcin. Although the serum osteocalcin level was lower in the group of subjects using high-dose inhaled steroids, suggesting an osteoblastic depression, bone density was not significantly different compared with the control group. CONCLUSIONS: This study shows that although the serum osteocalcin level was lower and the urinary phosphorus level was higher in subjects using high-dose inhaled steroids for a mean of 34 months, compared with a control group, no significant difference in bone density or other markers of bone metabolism was found between the two groups.

Administration, Inhalation↗
PubMed1994

Impact of cardiovascular disease on health care utilization in a defined diabetic population.

We studied the impact on annual medical care utilization and costs in 1988 of cardiovascular disease (CVD) in a population-based sample of 435 diabetic (DM) and 435 matched non-DM members of a Health Maintenance Organization. 58% of DM had at least one diagnosed CVD, compared to 26% of non-DM. 22.7% of outpatient visits, 38.7% of hospital days, and 30% of pharmacy expenditures by those with DM were primarily attributable to CVD. Up to 27% of all CABG recipients in the population had diabetes. In total, CVD directly accounted for at least 24% of total medical care costs among DM, compared to 12% of costs for non-DM. The HMO spent 4.5 times per person more on CVD care in DM than in non-DM members. Treatment with insulin was associated with increased peripheral vascular disease. After adjusting for age, CVD was more prevalent and generated longer hospital stays in DMs with nephropathy. The etiologic association between CVD and DM is well documented but CVD's clinical and economic importance in DM seems underappreciated.

Adult↗
PubMed1994

Adequacy of continuous ambulatory peritoneal dialysis: morbidity and mortality in chronic peritoneal dialysis.

Mortality for hemodialysis patients tends to be in excess of 20% per year, and it is generally agreed that outcome for continuous ambulatory peritoneal dialysis patients is comparable. Several investigators have suggested recently that continuous ambulatory peritoneal dialysis, as commonly practiced, may not provide adequate therapy, especially for larger patients and for those with no residual renal function. Unfortunately, a dose-response curve relating the amount of dialysis delivered and clinical outcome for continuous ambulatory peritoneal dialysis patients has not been constructed. Several methods of quantifying the dose of peritoneal dialysis are described. Both cross-sectional and longitudinal studies are reviewed. The conclusions of these studies are of limited value, however, because of their retrospective nature and the limited number of patients enrolled. Nevertheless, in aggregate, these studies suggest that survival may be improved by higher doses of dialysis. They also suggest that while malnutrition is relatively common in this patient population, higher doses of Kt/V are associated with higher protein intake (as measured by protein catabolic rate). Serum albumin is recognized as a strong predictor of clinical outcome and the protein catabolic rate may correlate directly with Kt/V, but there are studies that support and others that refute a correlation between Kt/V and serum albumin. Definitive answers to these questions are likely to be available in the near future. Two large multicenter studies are currently under way. Preliminary results may be available in the near future.

Blood Urea Nitrogen↗