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Biomedical subjects

D Gray

Publications and source records attributed to D Gray.

At least 253 records · Page 14Linked to original sources
PubMed1979

Dextran's effects on stressed lenses: water, electrolyte, and radioisotope studies.

To evaluate the beneficial effects of dextran 40 as an additive to infusion solutions, we studied an experimental model of lens stress with use of buffered, low calcium (Ca++)-containing solutions. Incubation in low Ca++ solutions (pCa = 10.7) for ten hours (stress period) resulted in lens swelling and electrolyte imbalances that were irreversible even with reincubation in physiologic, normal Ca++-containing media (pCa = 2.7) (recovery period). The addition of 6% or more of dextran to the media inhibited lens water gain during the stress period. It also rendered the resultant electrolyte imbalances reversible during the recovery period, thus exerting a protective effect. Radioisotope-tracer studies showed that dextran improved the ability of the lens to accumulate rubidium chloride Rb 86 and reduced its efflux during both the stress and recovery periods. Although dextran did not markedly decrease sodium chloride Na 22 uptake by lenses under stress, it did allow the lens to remove the 22Na during the recovery period.

Animals↗
PubMed1978

Oral versus intravenous high-dose steroid treatment of renal allograft rejection. The big shot or not?

50 episodes of renal allograft rejection were treated by oral prednisolone and 49 by intravenous methylprednisolone. Both treatments achieved reversal of rejection in approximately 60% of episodes. Morbidity-rates, as assessed by hypertension, oliguria, fluid retention, and infection, tended to be greater after oral treatment. When the results were reexamined for accelerated, acute, and chronic rejection episodes the only difference demonstrated was an increased frequency of fluid retention in patients treated by oral prednisolone for an acute rejection episode. There was no evidence that intravenous methylprednisolone was nephrotoxic.

Acute Disease↗
PubMed1978

The influence of ultrasound on the frequency of amniocentesis.

To determine the effect of development of ultrasonographic guidance techniques on the frequency of amniocentesis, we compared two two-year periods before and after the use of ultrasound. Statistically significant decreases in both the number of amniocenteses ordered and the number performed were observed. We concluded that ultrasound has been judiciously used and has not prompted an increased use of amniocentesis merely because of improved ease and safety. A slight decrease in the perinatal mortality rate mitigates against any compromise in the standard of antenatal care.

Amniocentesis↗
PubMed1976

Effects of group response-cost procedures on cash shortages in a small business.

The effect of a group response-cost procedure (accompanied by verbal and written instruction) designed to decrease cash shortages in a small business was evaluated with a reversal design. When cash shortages were subtracted from the six employees' salaries on days in which the shortage exceeded 1% of total daily sales, the magnitude of daily shortages sharply decreased. This response-cost contingency was used only three times throughout the study, with a maximum cost of $8.70 per subject over the 41-day period. The efficacy of the procedures may be due to either increased precision in change calculations, a decreased frequency of stealing from the cash register, increased shortchanging of customers, and/or increased incidents of register under-ringing. Ethical questions relative to the utilization of group punishment procedures are raised, and it was concluded that the procedures used were more humane than commonly used alternatives.

Journal Article↗
PubMed1972

Neuroblastoma.

Explore the source record for details and available documents.

Neuroblastoma↗
PubMed1965

Inactivation of oriented bacteria with polarized ultraviolet light.

Aligned deoxyribonucleic acid (DNA) molecules exhibit a large absorption anisotropy in the ultraviolet (UV) region of the spectrum (11). Also, the UV action spectra of most bacteria resemble the absorption spectrum of DNA (23), implying that inactivation is directly proportional to the UV absorbed by the bacterial DNA. Hence, the UV sensitivity of aligned uniaxial bacteria might be anisotropic with respect to polarization of the incident UV (17, 19). Any inactivation anisotropy would depend upon the orientation of DNA within the bacteria, as well as upon the alignment of bacteria, and could provide a more sensitive indication of in vivo DNA orientation than is presently available using optical methods (5, 12-16). Using an electric field of 3.5 x 10(6) cycles/second, samples of bacteria of strain LS-301 were aligned in a quartz cell and were irradiated with UV (lambda = 2652 A) polarized perpendicular and parallel to the alignment direction. The resultant survival curves resolved no inactivation anisotropy. This result is interpreted to mean that there was insufficient bacterial DNA alignment to give a detectable anisotropy. The minimum average DNA alignment necessary to have resolved an anisotropy is calculated to be 15 per cent in an axial direction (bases perpendicular to the bacterial axis) or 30 per cent in a radial direction (bases parallel to the bacterial axis).

Bacteria↗