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Biomedical subjects

S Brown

Publications and source records attributed to S Brown.

At least 667 records · Page 37Linked to original sources
PubMed1983

Clinical laboratory evaluation of Ames' Seralyzer Reflectance Photometer for total bilirubin and cholesterol.

We evaluated the dry-reagent technology for determining cholesterol and adult total bilirubin in serum with the Ames Seralyzer Reflectance Photometer. This instrument is designed to measure the intensity of light of a selected wavelength that is reflected from reagent-impregnated test strips saturated with sample. Regression analysis of the data for total bilirubin in adults (y) compared with corresponding values obtained with the Technicon SMAC (x) yielded the regression line: y = 1.07x + 2.5 (n = 128, r = 0.99). Day-to-day precision (CV) was 3.8% at 8.1 mg of bilirubin per liter, 5.34% at 48.3 mg/L. Regression analysis of the cholesterol data (y) vs cholesterol values obtained with an enzymatic cholesterol method (x) yielded the regression line: y = 0.91x + 191 mg/L (n = 100, r = 0.98). Day-to-day CVs for cholesterol were 3.6% at 1.62 g/L, 3.11% at 2.62 g/L.

Autoanalysis↗
PubMed1983

Improved determination of aluminum in serum by electrothermal atomic absorption spectrophotometry.

This method for determining aluminum in human serum involves electrothermal atomic absorption spectrophotometry. A longer drying time allows less pre-dilution of the sample, and the method also includes a flush cycle after atomization. Standard-addition methodology is used to eliminate matrix effects and the need for a standard curve. We used this method on serum from 50 normal persons and from 34 patients with chronic renal failure who were on long-term intermittent hemodialysis. The mean normal serum aluminum concentration was 6.1 micrograms/L (CV 2.7%), and values for the patients ranged from 13 to 475 micrograms/L.

Aluminum↗
PubMed1982

Antimicrobial resistance of Neisseria gonorrhoea in Bangkok: is single-drug treatment passé.

201 gonococcal isolates obtained from patients attending clinics in Bangkok were tested for in-vitro antimicrobial susceptibility. 42% of these isolates were penicillinase-producing Neisseria gonorrhoeae (PPNG); of the 116 isolates of non-PPNG 53% had a penicillin minimum inhibitory concentration (MIC) greater than or equal to 1 microgram/ml and the remainder had MIC greater than or equal to 0.06 microgram penicillin/ml. Similarly high in-vitro resistance was found for six of eight other antimicrobial agents tested. These high antimicrobial MICs reflect the difficulties encountered in selecting therapeutic agents for the control of gonorrhoea in Thailand. Single-drug treatment for gonorrhoea may no longer be effective in some settings. There is an urgent need to evaluate combination therapies appropriate to such settings.

Anti-Bacterial Agents↗
PubMed1982

Content bias in the neoplastic-related items of the National Board of Medical Examiners Part II Examination.

The Education Evaluation Committee of the American Association for Cancer Education (AACE) attempted to employ the neoplastic-related items from the National Board of Medical Examiners (NBME) Part II examination in a study correlating program characteristics at various medical schools with performance on the neoplastic-related items. All questions on the September, 1977 and April, 1978 NBME Part II examinations were reviewed by board certified medical oncologists who found an approximate 20% discordance between the AACE and NBME classifications. Content analysis of the neoplastic-related items disclosed a preponderance of questions related to gynecologic cancer with few questions concerning the major solid tumors: lung, breast and colorectal cancer. In addition, virtually no questions related to the psychologic impact of cancer or to the therapy of cancer were asked. We conclude that the use of item by item performance scores from the neoplastic-related items is inadequate for program analysis due to disagreements over what constitutes such an item and to content bias in the agreed upon items. We propose a coding system that may allow the results from current NBME examinations to be used in program evaluation.

Curriculum↗
PubMed1982

In vitro binding of gibberellin A(4) to extracts of cucumber measured by using DEAE-cellulose filters.

A rapid method for assaying [(3)H]gibberellin A(4) bound to a soluble protein from cucumber hypocotyls by using DEAE-cellulose filter discs is described. The binding is saturable, reversible with unlabeled gibberellin A(4), and has a half-life of association under nonequilibrium conditions at 0-4 degrees C of 6-7 min. By using this assay, the dissociation constant (K(d)) was estimated to be 70 nM and the number of binding sites, 0.4 pmol mg(-1) of soluble protein or 0.69 pmol g(-1) (fresh weight) of hypocotyls. The speed and reliability of the assay make it invaluable for kinetic studies involving competitors. Thus, it has been possible to show that gibberellins that are biologically active in a cucumber bioassay compete for binding to the same protein and their calculated affinity constants bear a direct relationship to their known activities in the cucumber bioassay. Gibberellins that are inactive in this bioassay and other plant hormones, such as indoleacetic acid, abscisic acid, and kinetin, show a noncompetitive interaction.

Journal Article↗
PubMed1982

A computer-based test item-bank for cognitive assessment of medical students during a clinical medicine clerkship.

The development and utilization of multiple-choice test items and the utilization of computer technology have significantly altered evaluation practices in medical schools. This paper describes the development and implementation of a computer-based multiple-choice test item-bank for use in a junior medicine clerkship. The computer program, ITEM-BANK, is an interactive system that stores and edits test items and constructs and prints an original copy of each test. Tests can be produced almost immediately by the clerical staff and the total developmental costs have been minimal. The program has reduced the amount of teaching time required to develop tests, and has enhanced the learning of essential information by medical students and residents. Teaching staff and student response has been enthusiastic and positive. Statistically significant Pearson correlation coefficients have been obtained between student performance on these tests and clinical evaluation and NBME Part II scores. The program has made a valuable contribution to the improvement of evaluation procedures in the Internal Medicine clerkship.

Alabama↗
PubMed1982

Histamine blocking agents in healthy and asthmatic subjects.

We compared the effects of two histamine receptor blocking agents, chlorpheniramine (H1) and cimetidine (H2) on the airways of healthy and asthmatic subjects. Eleven healthy subjects and ten asthmatic patients underwent histamine aerosol challenge. A threshold dose (T) for response to histamine was determined for each subject using maximal expiratory flow rates on partial expiratory flow rates on partial expiratory flow volume curves (MEF40 %[P]). On subsequent study days, the subjects were pre-treated with 8 mg of chlorpheniramine, 300 mg of cimetidine or a lactose placebo. Histamine challenge was performed two hours later with the individual's own T dose and doses one dilution below (T-1) and one dilution above (T+1) that dose. In both asthmatic and healthy subjects chlorpheniramine significantly reduced the bronchoconstrictor responses to histamine (p less than 0.02 and 0.05, respectively) as measured by MEF40 percent (P) at the T dose. When treated with cimetidine asthmatic patients displayed significantly more bronchospasm at T than with placebo (p less than 0.035). By contrast, pretreatment with cimetidine did not alter airway responses to histamine in healthy subjects when compared to placebo. We conclude that H2 receptors mediating bronchodilatation can be demonstrated in asthmatic patients but not in healthy subjects.

Asthma↗
PubMed1982

Efficacy of monensin as a cattle feed additive against the face fly and horn fly.

Four groups of eight Hereford and Hereford crossbred steers were monitored for the efficacy of monensin as a feed additive against the face fly and horn fly. Groups were assigned randomly to 3-ha grass-clover pastures. Two groups were supplemented with 1.1 kg ground corn/head daily (untreated), while the remaining groups were given 1.1 kg ground corn containing 100 mg monensin for 14 d and 200 mg monensin/head daily for the remainder of the 112-d trial. Fresh feces were collected from four steers in each group and bioassayed with newly hatched face fly and horn fly larvae. Fly mortality occurred in the larval stages, and the bioassay for feces from cattle given monensin at 200 mg/head daily showed an average of 19.9 and 23.3% fewer (P less than .01) face fly and horn fly pupae, respectively, than were recovered from feces of the untreated cattle. Surviving face fly and horn fly pupae were smaller (P less than .01) than the untreated pupae.

Animals↗