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Biomedical subjects

P Hyde

Publications and source records attributed to P Hyde.

At least 19 recordsLinked to original sources
PubMed1996

Long-term follow-up after surgical repair of ostium primum atrial septal defects in adults.

OBJECTIVES: We sought to determine the long-term survival rates and defect-related morbidity of adult patients who undergo surgical repair of an ostium primum atrial septal defect. BACKGROUND: The natural history of patients undergoing such surgical repair in adulthood remains unclear. METHODS: We followed up 33 patients who underwent surgical correction of an ostium primum atrial septal defect at our institution at a mean age of 42 years (range 20 to 73); 12 of these patients were > 50 years old at the time of operation. Four patients had moderate preoperative exercise incapacity (New York Heart Association functional class > II) and six had atrial fibrillation. Nine and four patients, respectively, had a preoperative mean pulmonary artery pressure > 25 mm Hg or pulmonary vascular resistance > 4 Wood U. Autologous pericardium was used to patch the defect in 30 patients (91%). Mitral valvuloplasty, consisting of cleft repair (n = 10), and mitral valve replacement (n = 2) were performed selectively. RESULTS: There were no operative deaths. At a mean follow-up interval of 5.3 years (range 1 to 18.2), all 28 surviving patients are free of exercise limitation (functional class 1). Late postoperative deaths occurred in five patients (15%) and were related to myocardial infarction, stroke, hepatic failure, renal failure or sepsis. Reoperation within the 1st postoperative year was required in two patients (6%) because of a residual ostium primum defect in one and severe mitral regurgitation in the other. The presence of advanced age at operation, symptoms, atrial arrhythmias, mitral regurgitation or moderately increased pulmonary vascular resistance did not predict late postoperative mortality, complications or functional capacity. CONCLUSIONS: An ostium primum defect can be repaired in adult patients with the expectation of excellent long-term results, independent of age at operation and preoperative mitral valve function and despite the presence of atrial fibrillation or moderately elevated pulmonary vascular resistance.

Adult↗
PubMed1996

T-cell receptor J beta 1/J beta 2 locus rearrangements in an HTLV-1-positive T-cell lymphoma with complex chromosomal aberrations.

We report a case of human T-cell lymphotropic virus type 1 (HTLV-1)-infected adult T-cell lymphoma that has multiple chromosomal abnormalities, including the presence of an additional 7q22-36, which contains the locus of the T-cell receptor (TCR) beta chain gene. Specific TCR J beta 1/J beta 2 gene rearrangements were detected in both marrow and peripheral blood DNA, with evidence of further evolution of the transformed clonal population within the peripheral lymphocytes. To our knowledge, this is the first case in which gene rearrangements have been associated with additional TCR loci. Consequently, it is advised that every effort should be made to correlate chromosomal abnormalities with gene rearrangement by molecular methods.

Adult↗
PubMed1995

Gastrointestinal perforation or vascular injury? A diagnostic dilemma for computed tomography in blunt abdominal trauma.

The authors describe an unconscious 20-year-old woman with Crohn's disease who was examined after a motor vehicle accident. During dynamic computed tomography after intravenous and oral administration of contrast material, contrast agent was observed in the peritoneal cavity. The source of the free contrast material was active bleeding, but it was initially mistaken for extravasation from the bowel. Exploratory laparotomy revealed transection of the superior mesenteric vein.

Abdominal Injuries↗
PubMed1994

Phenobarbital modifies seizure-related brain injury in the developing brain.

To investigate the potential role of drug therapy in preventing or exacerbating seizure-related brain injury in the prepubescent brain, we administered kainic acid to rats at postnatal day 35. Therapy with daily phenobarbital was started directly before or 1 day after kainic acid was administered, and was continued through postnatal day 153. Rats receiving phenobarbital had therapeutic concentrations during most of the 24-hour dosing period, but also experienced supratherapeutic peak concentrations. The animals were subsequently tested using the water maze (a measure of visuospatial memory), open field (a measure of activity level), and handling tests (a measure of emotionality). The frequency of spontaneous recurrent seizures was monitored during and after phenobarbital therapy. Kainic acid resulted in status epilepticus on postnatal day 35 in all the rats that received it but those receiving phenobarbital first manifested a shorter and less severe status epilepticus as compared to the rats given kainic acid alone. Rats starting phenobarbital immediately before kainic acid was administered did not differ from control rats on behavioral testing and had no subsequent spontaneous recurrent seizures and no histological lesions. Rats receiving kainic acid alone performed significantly poorer than did control rats in the water maze, were more aggressive, had histological lesions, and manifested spontaneous recurrent seizures. As compared to the group treated only with kainic acid, rats receiving kainic acid followed by phenobarbital at postnatal days 36 to 153 manifested similar aggressiveness and histological lesions, similar frequency of spontaneous recurrent seizures after phenobarbital taper, and even greater disturbances in memory, learning, and activity level.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
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↗
PubMedDate not supplied

Neuroprotective effect of felbamate after kainic acid-induced status epilepticus.

Felbamate (FBM), a newly developed antiepileptic drug (AED), was previously shown to offer some neuroprotective effects against hypoxic injury in both in vivo and in vitro studies. We administered FBM (100 or 300 mg/kg) to 30-day-old rats 1 h after they received a convulsant dosage of kainic acid (KA). Animals were then tested at age 80 days in the water maze, open field, and handling tests. Seizure latency was then tested by flurothyl inhalation. Animals that received 300 mg/kg FBM performed better in all three tests and had longer latencies to flurothyl-induced seizures than did animals that received vehicle. This study suggests that FBM may have some neuroprotective effects after KA-induced status epilepticus (SE).

Animals↗