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Biomedical subjects

R Gray

Publications and source records attributed to R Gray.

At least 361 records · Page 20Linked to original sources

Cerebral computed tomography in Reye syndrome.

The computed tomography (CT) findings in a case of Reye syndrome are presented. A striking discrepancy between the CT attenuation of infratentorial (elevated values) and supratentorial structures is observed.

Brain↗

Glucose-6-phosphate dehydrogenase deficiency and neonatal jaundice in Jamaica.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency was detected in 16 (69.6%) of a group of 23 neonates who had unexplained moderate or severe jaundice. This proportion is significantly more than the 9.4% observed or the 22.2% expected in Jamaican neonates who are not moderately or severely jaundiced (P less than 0.003), and significantly more than the 12.6% observed or the 21.0% expected in older Jamaican children and adults (P less than 0.003). Phenobarbitone therapy and phototherapy reduced the need for exchange transfusion but this was necessary in eight patients. Two babies developed kernicterus and one died. On the other hand, only two of 21 neonates who were identified as G6PD deficient at birth subsequently became moderately or severely jaundiced, and this could be attributed to other causes in both cases. These findings indicate that apparently spontaneous neonatal jaundice is important in infants who have the G6PD A--enzyme. However, the jaundice is probably precipitated by unknown factors to which the G6PD deficient neonate is more susceptible than the infant who is not G6PD deficient. THere is also a slightly increased incidence of G6PD deficiency in neonates who develop jaundice because of ABO or Rh(D) iso-immune disease, infection or prematurity.

Adolescent↗

Locus of control and symptoms of psychological distress among Chinese-Americans.

A sample of Chinese-Americans in the District of Columbia was drawn to examine the relationship between the locus of control, the personality factor, and two indices of symptoms of psychological distress. The findings indicated that the externals scored higher on symptomatology than did the internals. A multivariate analysis further compared the predictive utility of locus of control with other determinants of psychiatric symptoms, i.e., sex, marital status, SES, kinship and friendship tie, and amount of life change. The evidence showed that locus of control is an important determinant of Chinese-Americans' symptomatology. It accounted for a greater proportion of the variance in the two indices of psychological distress than did the other independent variables.

Acculturation↗

Chondrosarcoma of the nasal septum.

A rare case of chondrosarcoma of the nasal septum is presented. Wide excision of the tumour including the right orbit and part of the anterior cranial fossa was undertaken. Review of the literature shows that this is the treatment of choice and the radiotherapy does not prevent recurrence.

Chondrosarcoma↗

Wenckebach phenomenon occurring in the distal conducting system in a young adult.

This report describes the case of a young man who presented with right bundle-branch block and second degree atrioventricular block; intermittent episodes of Wenckebach periods were recorded. His bundle electrograms demonstrated progressive prolongation of the HV interval followed by block occurring distal to His. This report emphasizes the fact that the Wenckebach phenomenon as a manifestation of the distal conducting system disease can occur in young adults. The observations lend credence to the concept that Lenègre's disease can occur in young people.

Adult↗

Hemodynamic and metabolic effects of isosorbide dinitrate in chronic congestive heart failure.

To assess the potential beneficial effects of a nonparenteral vasodilator, sublingual isosorbide dinitrate (5 to 15 mg.) was administered in 12 patients with chronic congestive heart failure refractory to conventional therapy. Hemodynamic measurements were performed before and at 15 minute intervals after drug administration for 90 minutes. Venous capacitance was measured at 5 minute intervals. Myocardial metabolism was also studied in five patients before and after drug administration. Hemodynamic effects were characterized by a modest decrease in mean arterial pressure (85 +/- 3 to 78 +/- 2 [S.E.M.] mm. Hg) and substantial decrease in right atrial (10 +/- 1 to 6 +/- 1), pulmonary arterial (39 +/- 4 to 30 +/- 4) and pulmonary capillary wedge pressures (28 +/- 2 to 21 +h- 2). These changes were accompanied by an increase in venous capacitance (2.46 +/- 0.16 to 3.99 +/- 0.24 c.c./100 c.c. of tissue). Along with a decrease in left ventricular filling pressure, cardiac index increased (1.99 +/- 0.13 to 2.37 +/- 0.15 L./min/M.2). No significant effect on heart rate was seen. Delta P/delta t, an index related to left ventricular dp/dt, increased in all but one patient (253 +/- 31 to 298 +/- 39 mm. Hg/sec.) (p less than 0.02 for all changes) in the face of decreased preload and afterload and unchanged heart rate, suggesting improved contractile state. A decrease in coronary blood flow (165 +/- 13 to 131 +/- 15 c.c./min.) and myocardial oxygen consumption (18.1 +/- 1.6 to 14.5 +/- 1.6 c.c./min.) was noted (p less than 0.02). No change in arterial-coronary sinus oxygen difference or lactate extraction was observed. These data demonstrate that the objectives of therapy in congestive heart failure, namely improved forward output and decreased ventricular filling pressures, can be achieved without metabolic deterioration by using sublingual isosorbide. The mechanisms responsible are related to diminished impedence to ventricular ejection and peripheral pooling of blood. Since the duration of action does not usually exceed 90 minutes, frequent drug administration may be a source of patient inconvience.

Administration, Oral↗

Use of a balloon-tipped flotation electrode catheter for cardiac mounting.

A new balloon-tipped flotation catheter equipped with two pairs of electrodes has been developed for simultaneous monitoring of cardiac rhythm and hemodynamics as well as for temporary emergency atrial, ventricular and atrioventricular sequential pacing. Experience in 43 patients demonstrates the following: (1) The catheter can be passed and positioned with the tip in the pulmonary artery or its branches at the bedside with the use of fluoroscopy as easily as the standard (Swan-Ganz) catheters. (2) With the catheter in the proper position ans with the use of appropriate filters (proximal, 50 to 300 hertz; distal, 15 to 300 hertz), the intracavity electrograms recorded from the proximal and distal pair of electrodes provide characteristic high right atrial and right ventricular signals, virtually free of noise artifact, baseline drift and respiratory variation, that are particularly suitable for automated on-line monitoring of cardiac rhythm. (3) When indicated, atrial, ventricular or atrioventricular sequential pacing can be initiated without delay. (4) Large artifact-free right ventricular intracavitary signals can be used for reliable and consistent operation of any device requiring QRS triggering mechanisms. (5) Monitoring of pulmonary arterial or pulmonary capillary wedge pressure and withdrawal of blood samples from the central circulation is possible. This device can be particularly useful in patients with hemodynamic difficulties as well as arrhythmias.

Arrhythmias, Cardiac↗