Biomedical subjects
Publications and source records attributed to J Magee.
A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.
A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.
A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.
This review discusses recent data regarding the different types of voltage-gated Na+, Ca2+, and K+ channels in dendrites of CA1 pyramidal neurons and their function for synaptic integration and plasticity. Na+ and Ca2+ channels are uniformly distributed throughout the dendrites, although Na+ channels in the soma and proximal dendrites differ in their inactivation properties from Na+ channels in more distal regions. Also, different regions of the neuron express different subtypes of Ca2+ channels. K+ channels are unevenly distributed, with the distal dendrites expressing a more than fivefold greater density of a transient A-type K+ channel than proximal regions. These K+ channels exert profound control over the excitability of the pyramidal neurons and the spread of synaptic potentials throughout the dendrites. The ways in which the active properties of dendrites may contribute toward the induction and maintenance of long-term synaptic plasticity are discussed.
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Appendage formation is organized by signals from discrete sources that presumably act upon downstream genes to control growth and patterning. The Drosophila vestigial gene is selectively required for wing-cell proliferation, and is sufficient to induce outgrowths of wing tissue from eyes, legs and antennae. Different signals activate separate enhancers to control vestigial expression: first, in the dorsal/ventral organizer through the Notch pathway, and subsequently, in the developing wing blade by decapentaplegic and a signal from the dorsal/ventral organizer. Signal integration must be a general feature of genes like vestigial, that regulate growth or patterning along more than one axis.
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It has been recommended that samples submitted for microbiological examination should be retained for 48 hours after issue of the final report. In order to ascertain whether reproducible results could be achieved following storage of sputum specimens, two laboratories each re-cultured 100 samples 48 hours after their report had been issued and a further laboratory re-cultured 100 samples 48 hours after receipt. Discordant results were obtained in only 5-25% of specimens, indicating that potential respiratory pathogens could survive storage.
The purpose of this descriptive study was to identify unsafe uses of prescription, over-the-counter and home remedies used in the treatment of pediculosis. Twenty-seven families with 119 children were visited at home and interviewed about their use of remedies for head lice. In addition to prescription and over-the-counter products home remedies were commonly used. Kerosene, alcohol, insecticides, and head shaving were some of the home remedies reported.
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A riboflavin-binding hexamerin isolated from pupal hemolymph of Hyalophora cecropia has a native M(r) of 510,000, subunit M(r) of 85,000, and a 5% carbohydrate content. An intrachain cross-link was confirmed in protease limit digests. Ellman titration confirmed the presence of a sulfhydryl group, which is needed for this linkage. Though Cu2+ is known to promote the linkage, heavy metals were not detected in the isolate. Heat denaturation released ligand with the absorbency, fluorescence spectra, and chromatographic behavior of riboflavin. Binding resulted in substantial quenching of the fluorescence of both the isoalloxazine in riboflavin and of aromatic groups in the apoprotein. Kinetic analysis indicated a KD of 2.5 x 10(-7) M for riboflavin, 1.3 x 10(-7) M for lumiflavin, and greater than 1 x 10(-6) M for FMN and FAD. Over four moles of flavin were bound per mole of hexamerin. The amount of riboflavin in pupal hemolymph is sufficient to occupy only 2-3 of these sites. Riboflavin is also associated with lipophorin and vitellogenin, but the molar ratios after protein isolation were low. On a standard laboratory diet, riboflavin is in great excess, but most of it is apparently excreted before the apoprotein first appears in the hemolymph, just before wandering. The concentration of riboflavin-binding hexamerin rises to 15-30 mg/ml in pupae; relative to other hexamerins, very little is stored in the fat body. All of the apoprotein and 75% of riboflavin disappear from the hemolymph during adult development. An amount of flavin at least equal to that stored in pupal hemolymph is transferred to the eggs formed during this period.
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The control of behavior by stimuli presented during sleep, and related effects on sleep and daytime sleepiness, were investigated in 17 older (age = 60-74 years) adults. Experimental subjects (N = 8) were trained while awake to terminate tone presentations by taking a deep breath. Tones were then presented following sleep onset for four consecutive nights with a mean intertone interval of 4 min. Control subjects (N = 9) slept in the laboratory but did not receive tones. The daytime sleepiness of both groups was assessed by recording latency to sleep onset in a morning and afternoon nap test. It was found that the experimental subjects responded reliably to the tones. Responding, however, was almost invariably accompanied by disruption of sleep and overall sleep structure was markedly altered. Surprisingly, the daytime sleepiness of experimental subjects was not reliably greater than that of control subjects.
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The turnover of cerebrospinal fluid (CSF) glucose was studied in cats during steady-state perfusion. In all experiments, the perfusion fluid contained either tracer [14C]glucose alone or tracer glucose along with 4.45 mM unlabeled glucose. In some studies, serum glucose was lowered with insulin. The concentration of glucose and [14C]glucose in the effluent fluid was measured, and the distribution of 14C between glucose and lactate was determined by chromatography. From these values, the extraction of glucose and the metabolism of glucose to lactate were calculated. From the decrease in the specific activity of glucose in the perfusion fluid, the influx of glucose from serum was also determined. During steady-state perfusion, 71% of the radioactivity was recovered in the effluent fluid: 50% in the form of glucose, 6% in the form of lactate, and 15% in forms that were not identified. Thus, 50% of the perfusion fluid glucose was cleared, of which 29% was extracted and 21% metabolized. The influx of glucose was proportional to the serum glucose when the latter was about 2.5 mM or 10.0 mM. During perfusion with tracer glucose only, the concentration of glucose in the effluent fluid was 25% that of serum. The transport of glucose from serum was independent of the glucose concentration gradient between serum and perfusion fluid. However, when perfusion fluid glucose concentration was greater than that of serum, transport was inhibited. These studies suggest that in maintaining CSF glucose at a lower concentration than serum glucose, with equal amounts of glucose entering and leaving the CSF, 50% of CSF glucose concentration cleared is replaced by 25% of serum glucose concentration.
An enzyme linked immunosorbent assay (ELISA) method for the detection of antibodies to platelets and leucocytes is presented. The method can be used for large numbers of samples. The method is objective when photometers are used. Approximately 50% of all cases of possible autoimmune thrombocytopenic purpura (A.T.P.) and unexplained neutropenia showed positive results. The results obtained using ELISA and standard tests for leucocyte and platelet antibodies are compared. The ELISA tests may also detect immune complexes.