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Biomedical subjects

P Hyde

Publications and source records attributed to P Hyde.

14 recordsLinked to original sources
PubMed1987

Antigenic differences between human platelets and megakaryocytes.

To investigate the apparent paradox in the observation that most patients with immune thrombocytopenias have normal or increased numbers of megakaryocytes (MKs), the extent of antigenic cross-reactivity between normal platelets and MK was examined. Indirect immunofluorescence and ultrastructural studies were carried out by means of four antisera specific for platelets: anti-GpIb, anti-GpIIb/IIIa, anti-PLA1, and an antiserum from a patient with quinidine-induced thrombocytopenia. Following incubation of freshly collected marrow with these antisera, MK were first identified by phase-contrast microscopy and then inspected for fluorescence. Almost all MKs were found reactive with the last three antisera, albeit to a variable extent. In contrast, only 24% reacted with anti-GpIb. The pattern of fluorescence, ie, rim, partial or cytoplasmic, appeared to be related to the extent of MK fragmentation. Only rim fluorescence of living MKs could be interpreted to indicate that the platelet epitope was exposed on the surface of the precursor cell. The observations suggest that platelet antigens are variably expressed on the plasma membranes of MKs. In a clinical setting, the heterogeneity among platelet target antigens and the extent to which these are exposed on MKs at various stages of maturation may dictate the severity of the thrombocytopenia and degree of ineffective thrombocytopoiesis.

Antigens, Human Platelet↗
PubMed1981

Anxiolytic effects of low dosage nitrous oxide-oxygen mixtures administered continuously in apprehensive subjects.

We observed the effect of low doses of nitrous oxide on the cardiovascular and respiratory systems, the cortisol output in blood and saliva, and the degree of sedation and analgesia of 20 volunteers. A psychologic screening inventory was also performed. We found nitrous oxide, at low dosage, to be primarily an anxiolytic and not an analgesic or amnesic agent. The nasally inhaled concentrations necessary to induce an anxiolytic effect varied from subject to subject, ranging from 30% to 65% and averaging 35% to 40%. This finding justifies the use of the gas to relieve anxiety instead of nonvolatile parenterally administered psychosedatives and narcotics. Nitrous oxide is preferable because its action is established within several minutes, it is rapidly eliminated at the conclusion of a procedure, and the sensorium is clear after five or six minutes. The gas is simply and safely administered with fail-safe apparatus designed specifically for this purpose. The technic is admirably suited for use in ambulatory care units where minor surgical or dental procedures are performed.

Adolescent↗
PubMed1980

Chronic use of triazolam: the effects on the sleep patterns of insomniacs.

The present study was designed to evaluate the effects of triazolam 0.5 mg on the sleep of insomniac patients when given for 3 weeks. The results showed that both acute and chronic triazolam administration are effective in decreasing sleep latency, increasing sleep duration, increasing sleep efficiency and decreasing total wake time without producing major effects on sleep staging. Sleep Stages 1 and 2 were significantly altered by drug treatment but in a positive direction. This change is primarily attributable to the significant decrease in sleep onset. Deep sleep and REM were not significantly changed during triazolam treatment nor was there any evidence of REM rebound after discontinuation of the medication. It was noted that some of the sleep parameters measured shifted toward baseline measures in the first night after triazolam treatment was terminated. However, the total recovery period recorded (7 days) showed the quality and quantity of sleep obtained to be improved over baseline measures. The recovery data compared favourably with those improvements noted during chronic administration of triazolam. It was also found that 3 weeks of triazolam 0.5 mg usage did not result in tolerance to its hypnotic properties. Thus, triazolam maintains its hypnotic effectiveness throughout 3 weeks of administration.

Adolescent↗