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Biomedical subjects

A Lee

Publications and source records attributed to A Lee.

At least 757 records · Page 42Linked to original sources
PubMed1980

[3H]ouabain autoradiography of frog retina.

The kinetics and distribution of ouabain binding in retinas of Rana pipiens were examined quantitatively by scintillation counting and freeze-dry autoradiography. The time-course of binding at several concentrations was consistent with a bimolecular reaction. Estimated equilibrium binding levels gave a Michaelis-Menton relationship with a Km = 8.3 x 10(-8) M and a maximum binding level (Bmax) = 4.4 x 10(-8) mol/g protein. The distribution of binding sites measured autoradiographically varied considerably between layers. The photoreceptor, inner plexiform, and optic nerve fiber layers exhibited the heaviest binding. Within the photoreceptor layer, binding was nonuniform. Binding in the outer segment decreased distally, averaging approximately 4% of that in the proximal receptor layers (Bmax = 4.6 x 10(-6) M). The origin of the outer segment activity is uncertain at light microscope resolution, as it may be a result of inner segment calyceal processes. Binding within the proximal receptor layers was also nonuniform. Several peaks were observed, with those at the inner segment and synaptic layers being especially noticeable. Assuming an absence of glial cell binding in the proximal receptor layers, we calculated there to be 13 x 10(6) ouabain or Na+,K+ pump sites per rod receptor. Limited measurements suggest a Bmax of approximately 8 x 10(-6) M for the inner plexiform layer.

Animals↗
PubMed1980

Reporting practices of microbiology laboratories.

Results of investigations on typical specimens were circulated to Australian microbiologists, who were asked to draft reports on the basis of the data provided. Many laboratories were found simply to report the results of their activities without explanations. This was true whether the finding was that of a Gram-negative rod in a postoperative sputum or an anaerobic diphtheroid in a blood culture. There was diversity of views as to what constituted probable contamination in a urine specimen. Often no clearcut verdict was given, nor did the report indicate when no conclusion was possible. Remedial measures are discussed.

Australia↗
PubMed1979

Consumer survey on microbiology reports.

5 typical microbiology reports were circulated to the medical staff of a 900-bed teaching hospital and they were asked for their interpretations. Approximately 160 completed replies were received and it was clear that the reports were often misinterpreted; one report (isolation of a gram-negative rod from sputum) was misinterpreted by four doctors out of five. The reasons for this failure of communication seem to be the use of jargon and unfamiliar names of bacterial species, and use of ill-defined reporting conventions. The omission of a clear-cut conclusion from many reports also contributed to misunderstanding. These deficiencies in reporting practices result in unnecessary antibiotic therapy and unnecessary work for the laboratory, since clinicians are more likely to ask for a repeat of a test with a doubtful interpretation. Communications with clinicians would be more effective if microbiologists ensured that each report is free of jargon, states what conclusion can be drawn from the test, and makes recommendations, where appropriate, for antibiotic therapy.

Aged↗
PubMed1979

The preservation of surface-associated micro-organisms prepared for scanning electron microscopy.

Scanning electron microscopy (SEM) has become a popular means of studying micro-organisms which associate with surfaces. However, as yet no detailed examination has been made of the influence of specimen preparation on the number of organisms finally seen on the SEM screen. In this investigation critical assessment is made of the influence of a wide range or preparative factors on the preservation of filamentous bacteria associated with the epithelial surfaces of rat intestine. Organisms were quantitated using a rigorous counting method (transect line analysis); statistical testing of these counts enabled the comparison of different preparative factors. The composition of the fixative was found to significantly influence the number of organisms preserved; of the fifteen fixatives studied, Karnovsky's fixative with ruthenium red best preserved surface-associated organisms. The influence of other factors on the number and appearance of preserved organisms was also examined. These factors included the washing of specimens prior to fixation, the storage of fixed specimens, and the handling and storage of critical point dried specimens. The results are discussed with reference to the optimal methods for preparing specimens for SEM.

Animals↗
PubMed1979

Effects of maternal drinking on neonate state regulation.

Sleep-awake state distribution during inter-feed intervals over a 24-hour period on the third day of life was investigated by means of a continuous non-intrusive bassinet sleep monitor. 31 infants were studied: 14 born to mothers who drank heavily throughout pregnancy (group A), eight whose mothers modified their heavy drinking (group B) and nine whose mothers never were heavy drinkers (group C). Over the 24-hour period, group A infants slept less than those in group B. In comparison with group C, group A infants had a larger proportion of quiet sleep episodes interrupted by awake or unclassified epochs, and were more restless, with more frequent major body movements. These pilot observations suggest that heavy maternal consumption of alcohol, when continued throughout pregnancy, is associated with a disturbance of sleep-awake state distribution. Successful therapy of heavy drinking during pregnancy may improve the physiological competence of the newborn to regulate sleep-awake states and facilitate interaction between mother and infant.

Adolescent↗
PubMed1978

Once daily propranolol in the treatment of mild to moderate hypertension: a dose range finding study.

Propranolol was administered in a single dose of 80 mg, 120 mg, 160 mg, 240 mg, or 320 mg, to 23 patients with essential mild to moderate hypertension in a randomised, double-blind cross-over study. All treatments produced a significant fall in lying and standing blood pressures compared with placebo, but there was no statistically significant difference in the effects of the different doses. The percentage of patients showing a satisfactory fall in blood pressure was not different in the five treatment groups. The major anti-hypertensive effect of each dose was present by two weeks. The frequency of side-effects were similar on all the doses.

Adult↗