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Biomedical subjects

C Davis

Publications and source records attributed to C Davis.

At least 217 records · Page 12Linked to original sources
PubMed1993

Ionic composition of cisternal CSF in acute respiratory acidosis: lack of effect of large dose bumetanide.

Sodium/chloride cotransport carrier is known to be involved in transepithelial fluid absorption and secretion in various tissues. Recent studies indicate that Na,K,2Cl cotransport carrier also exists in the choroid plexus cells and inhibition of the carrier alters ionic composition of the choroidal tissue. In this study, we report the effects of large dose intravenous bumetanide, a potent inhibitor of Na,K,2Cl carrier, on cisternal CSF ionic composition in acute respiratory acidosis in pentobarbital-anesthetized mechanically ventilated dogs. Renal pedicles were ligated to prevent bumetanide-induced diuresis. The experimental group (Group II, n = 7) received 50 mg/kg of bumetanide intravenously and Group I (the control group, n = 7) received the vehicle. Analysis of serum and choroidal plexus tissue revealed bumetanide concentration of approximately 10(-5) mol/L in Group II. During 5 h of acute respiratory acidosis in both groups, the mean PaCO2 increased approximately 25 mm Hg, with comparable changes in CSF PCO2. In both groups, CSF [HCO3-] and [H+] increased approximately 3 mEq/L and 20 nEq/L, respectively. Furthermore, changes in CSF [Na+], [K+], [Ca2+], [Mg2+], [Cl-], and [Na(+)-Cl-] were also similar and were not significantly different from each other. These data show that bumetanide, at the dose that inhibits NaCl cotransport carrier, does not significantly affect ionic composition of cisternal CSF.

Acid-Base Equilibrium↗
PubMed1993

False-negative urine latex particle agglutination testing in neonates with group B streptococcal bacteremia. A function of improper test implementation?

Although blood cultures remain the most specific indicator of Group B streptococcus (GBS) sepsis, a potentially life-threatening infection in neonates, test results may not be available for 24 to 48 hours. Detection of GBS antigen in the urine by latex particle agglutination (LPA) may speed diagnosis. This study analyzed the sensitivity of the GBS urine LPA assay under clinical conditions. The urine of neonates with early-onset GBS bacteremia was analyzed for GBS antigen over a three-year period at six military medical centers. Overall, 53.5% (38/71) of infants with positive blood cultures had a positive urine LPA test. Only one medical center routinely followed manufacturer's recommendations to concentrate urine specimens before testing. These data suggest that the sensitivity for the urine LPA assay, when performed on unconcentrated urine, is lower than previously reported. Clinicians should insist that the laboratory maximize sensitivity by concentrating urine prior to GBS LPA testing.

Antigens, Bacterial↗
PubMed1993

A diagnostic and therapeutic N-of-1 randomized trial.

The objective of this paper is to study the effect of amitriptyline on a young woman with symptoms of lightheadedness, palpitations, somnolence and fatigue. We conducted a single case (N-of-1) randomized trial including three pairs of treatment periods. Each pair included one four-week period when the patient was receiving amitriptyline and one four-week period when the patient was receiving placebo. The clinical setting was a secondary care internal medicine practice. During active treatment periods, amitriptyline was given in a dose of 100 mg each evening. Efficacy symptoms included lightheadedness, headaches and somnolence/fatigue. Side-effects of dry mouth and constipation were also monitored. Each symptom was rated on a seven point scale in which higher numbers denoted fewer symptoms. For the combined efficacy score, the mean difference in scores and the associated standard error was in favour of amitriptyline. The most profound effect was on sleepiness. These differences represent clinically important treatment effects. Dry mouth and constipation were worse on the active drug, but differences did not reach statistical significance. Our experience suggests the usefulness of N-of-1 randomized trials in outpatient medical practice, including psychiatric practice.

Adult↗
PubMed1993

Is there a role for selective monoamine oxidase inhibitor therapy in bulimia nervosa? A placebo-controlled trial of brofaromine.

Pharmacologic and cognitive behavioral therapies have been advocated in the treatment of bulimia nervosa (BN). Brofaromine, a selective and reversible inhibitor of monoamine oxidase-A was selected for a double-blind, placebo-controlled evaluation because of previous demonstrated monoamine oxidase inhibitor efficacy in BN and because of its safer adverse reaction profile. Thirty-six female patients who met DSM-III-R criteria for BN were randomly assigned to the drug group (N = 19) or to the placebo group (N = 17) for an 8-week outpatient trial. Brofaromine produced a significant effect in decreasing episodes of vomiting throughout the trial, although comparable reductions in episodes of binge eating were found in both groups. Also, there were no advantages of drug over placebo on improvements in attitudinal measures and shape or on self-report ratings of depression and anxiety. However, a significant proportion of the subjects on brofaromine lost weight when compared with the placebo group. Methodologic issues including subjective assessment measures, placebo response rates, and the elucidation of responder subgroups are discussed.

Adolescent↗
PubMed1992

Transcultural aspects of eating disorders: a critical literature review.

A review of studies addressing anorexia nervosa and bulimia nervosa among Native Americans, African-Americans, Hispanics, Asians, Africans, and Middle Easterners yielded only 35 studies, of which 22 were qualitative case reports, three were clinical quantitative studies, and ten were non-clinical quantitative studies. The case studies reported symptoms similar to those of Caucasian patients, and eating disorders were reported in all SES classes. The clinical studies, all reported from Asian countries, described a number of cases for eating disorders quite different from one another. The non-clinical quantitative studies reported a number of cases consistent with the ranges previously reported for controlled samples of non-clinical Caucasian populations. We found few or no quantitative studies on eating disorders from Hispanic, Middle Eastern, African, or Asian countries other than Japan.

Adolescent↗
PubMed1992

Distinguishing ischemic cardiomyopathy from nonischemic dilated cardiomyopathy with coronary echocardiography.

Transthoracic echocardiographic examination of the proximal left coronary system was performed in 59 patients who had dilated cardiomyopathy to determine if this technique could distinguish between ischemic and nonischemic dilated cardiomyopathy. With use of annular array transducers (3.5 or 5 MHz) and digital image processing, echocardiographic visualization of the coronary arteries was successful in 55 (93%) of 59 patients. As assessed by coronary angiography, 32 subjects had ischemic cardiomyopathy and 27 had nonischemic cardiomyopathy. Twenty-seven (84%) of the 32 patients who had coronary artery disease and 24 (89%) of the 27 patients with nonischemic cardiomyopathy were correctly identified. The accuracy of coronary echocardiography was 86% in the entire study group and 93% when patients with inadequate studies were excluded. All subjects who had ischemic cardiomyopathy had evidence of disease by coronary echocardiography or segmental wall motion abnormalities. Multivariate analysis permitted correct classification of 93% of all subjects based on the results of the coronary echocardiogram, evaluation of segmental wall motion and a history of prior myocardial infarction. The correct diagnosis was made in 86% when the results of coronary echocardiography were excluded from analysis using all other echocardiographic and clinical variables. Transthoracic coronary echocardiography can be performed with a high degree of success in patients with dilated ventricles and the technique can reliably distinguish between ischemic and nonischemic dilated cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed1992

Phase II study of pulse 5-fluoro-2'-deoxyuridine and leucovorin in advanced colorectal cancer patients previously treated with chemotherapy.

Because of possibly better activity against colorectal cancer of 5-fluoro-2'-deoxyuridine [floxuridine (FUdR)] compared to 5-fluorouracil (5-FU), and because of improved therapeutic results of leucovorin (LV) modulation of 5-FU, we carried out a phase II study of systemic FUdR and LV in 5-FU-treated patients with metastatic colorectal cancer. Weekly regimens consisted of a 4-hour infusion of LV, 200 mg/m2, and at 2 hours, a 2-hour infusion of FUdR, 30 mg/kg, with weekly dose escalation, as tolerated, to a maximum of 60 mg/kg. Twenty-nine patients were treated; they had a median age of 66, most had good performance status, and all had measurable disease. All had received 5-FU, although three had received it as adjuvant therapy only. Two patients had partial responses (6.9% response rate, 95% confidence interval, 1.9-21.9%) lasting 29 and 19 weeks, and five had stable disease. Median time to progression was 8 weeks and median survival was 36.5 weeks. The median number of courses was 6.5; escalation of FUdR was carried out in 27 patients. Hematologic toxicity was minimal and gastrointestinal toxicity was most frequent, although mild. This regimen, although well tolerated, is minimally effective in previously 5-FU-treated patients with metastatic colorectal cancer.

Adenocarcinoma↗
PubMed1992

Psychopathic disordered, mentally ill, and mentally handicapped sex offenders: a comparative study.

Although there currently exists a large amount of research on the characteristics and treatment of psychopathic disordered (PD) sex offenders, little if any empirical studies have addressed the mentally ill (MI) and mentally handicapped (MH) offender populations. A total of 106 PD, MI, and MH sex offender records from Rampton (Special) Hospital were reviewed for the study. Offender categories were compared by age of first documented sex offence, IQ at the time of admission, sex offence type, frequency of each offence type, history of violence during sex offences, age and gender of sex offence victims and number of victims for age and gender. Results revealed that 88 per cent of PD, 98 per cent of MI, and only 56 per cent of MH offenders' victims were female. Further analysis revealed that PD and MI offenders' victims were primarily female, with the largest proportion being pubescent and adult females. MH offender victims were primarily males and females under the age of 16. IQ correlated positively with history of violence during sexual assault and mean IQs were higher for 'violent' than 'non-violent' offenders in each offender category. A discussion of these and other significant findings, as well as implications for clinical treatment, is presented.

Adolescent↗
PubMed1992

Predictors of HIV-1 disease progression in early- and late-stage patients: the U.S. Army Natural History Cohort. Military Medical Consortium for Applied Retrovirology.

HIV-infected individuals in both early and late stages of HIV disease were evaluated over 2 years to assess temporal trends and determinants of disease progression. The Walter Reed (WR) staging system was used to categorize patients into an early-stage cohort (WR Stages 1 and 2, N = 1183) and a late-stage cohort (WR Stage 5, N = 260) based on the initial clinical evaluation. Progression was defined as the occurrence of Stage 5 disease or beyond for the early cohort and Stage 6 disease or beyond for the late cohort. The cumulative incidence of progression was 15.7% (137 events) for the early-stage cohort, and 53.7% (85 events) for the late-stage cohort. Baseline CD4+ T lymphocyte (T4) count was the most significant marker of progression: 26% of WR Stage 1 or 2 patients with T4 lymphocytes below 500/mm3 progressed, compared with 12% with T4 lymphocytes at or above 500/mm3. In late-stage individuals, 83% with T4 lymphocytes under 200/mm3 progressed, compared with 27% with T4 lymphocytes at or above 200/mm3. Older age was associated with progression in both early- and late-stage groups. Differences in the rates of disease progression were not significant between blacks and whites or between men and women. Two-year rates of progression among the late-stage patients dropped from 78 to 47% between 1986 and 1988. This contrasted with progression rates in the early-stage cohort, which remained stable: 18% for those entering follow-up in 1986 and 17% for those entering follow-up in 1988. These data indicate a significant slowing of HIV disease progression rates and mortality rates among individuals with late-stage disease that is temporally associated with the increased availability and use of therapies. With control of T4 lymphocyte count, age, and calendar time, neither gender nor race was significantly associated with progression in either early- or late-stage patients.

Adolescent↗
PubMed1992

Trypanosoma cruzi in wild raccoons and opossums in North Carolina.

Trypanosoma cruzi was isolated from 1 of 12 (8.3%) opossums and 3 of 20 (15%) raccoons from the piedmont area of North Carolina. Although T. cruzi has been isolated previously from wild mammals in the southern United States, the present study is the first published report of naturally occurring T. cruzi infection of wild mammals in North Carolina. All 4 isolates were maintained successfully in axenic culture and in murine fibroblasts. In addition, intraperitoneal injection of 1 x 10(6) culture forms of 1 of the opossum isolates into C3H mice resulted in low but detectable parasitemias as early as day 6 of infection. These mice resolved parasitemia and survived infection. Intraperitoneal injection of 1 x 10(6) culture forms of a raccoon isolate resulted in the death of 3 out of 4 mice. Surprisingly, parasitemias were never detected in the peripheral blood of these mice. Infection of murine fibroblasts in vitro resulted in the presence of intracellular amastigote stages characteristic of T. cruzi.

Animals↗