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Biomedical subjects

J H Goldstein

Publications and source records attributed to J H Goldstein.

At least 55 records · Page 3Linked to original sources
PubMed1981

The effect of changing extracellular osmolality on water transport in the human red blood cell as measured by the cell water residence time and the activation energy of water transport.

A pulse NMR technique employing low extracellular Mn2+ concentrations has been used in following the effect of variations in extracellular osmolality on water transport through the human red blood cell membrane. We report results including the effect of osmolality on the cell water lifetime (tau a) and, for the first time, the effect on the proton spin-spin relaxation of the intracellular water (T2a) and the activation energy for the water transport process. Current results are encouraging in correlating the effects seen in this study with suspected membrane functional changes occurring in both in vivo and in vitro aging and during in vitro preservation attempts.

Adult↗
PubMed1981

Time dependence of the effect of p-chloromercuribenzoate on erythrocyte water permeability: a pulsed nuclear magnetic resonance study.

Pulsed nuclear magnetic resonance spectroscopy is employed to determine the time dependence of the change in erythrocyte water permeability following exposure to p-chloromercuribenzoate (PCMB) or p-chloromercuribenzene sulfonic acid (PCMBS). pH variation was used to examine the environment of the sulfhydryl groups reactive to these drugs. PCMB reacted with at least two sulfhydryl groups which affect water permeability. This was shown by the double exponential character of the change in erythrocyte diffusional permeability with time after PCMB addition. However, only one inhibition rate process could be distinguished following PCMBS exposure, suggesting that one site bound by PCMB is not accessible to PCMBS. This site is postulated to be located in a hydrophobic region of the membrane, whereas the site reached by both drugs is located in the normal anion permeation channel. The effect of pH on the degree of inhibition due to each component and the inhibition rates is explained in terms of its effect on solubility of the reagents in the membrane and variation of the dissociated-to-undissociated ratio of PCMB.

4-Chloromercuribenzenesulfonate↗
PubMed1981

Comparison of intramuscular and intravenous succinylcholine on intraocular pressure.

The effect of succinylcholine on intraocular pressure was determined in one group of patients who received the drug intravenously, compared with a similar group receiving the drug intramuscularly. The group receiving intravenous succinylcholine showed a significantly earlier rise in pressure and a significantly higher rise in pressure compared to the group receiving the drug intramuscularly. In both groups the pressure returned to normal within five minutes. It is suggested that in cases with a ruptured globe or wound leak in which succinylcholine is used to facilitate tracheal intubation, the drug should be administered intramuscularly.

Adolescent↗
PubMed1980

Effect of monocular vertical displacement on the deviation in primary position.

The surgical correction in the primary position was compared in one group of patients who underwent horizontal surgery without an A or V pattern with a matched group who underwent horizontal surgery with monocular vertical displacement for the A and V patterns. No significant difference was found, and it was concluded that the determination of the amount of horizontal surgery is the same whether monocular vertical displacement is performed or not.

Adolescent↗
PubMed1979

Pulse nuclear magnetic resonance measurements of water exchange across the erythrocyte membrane employing a low Mn concentration.

A simple, precise, and rapid pulse nuclear magnetic resonance technique for measuring the rate of water exchange across the erythrocyte membrane is presented. The technique is based upon the nonlinear fit of Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation time data of blood doped with 1.7 mM MnCl2 to the general two-compartment exchange condition. Previous approaches using CPMG data required high MnCl2 concentrations (25-53 nM), shown in this work to induce systematic errors ranging from 35 to 45%. At 23 degrees C the average residence time of a water molecule inside the erythrocyte (tau a) is 21.0 +/- 0.6 ms (SE). The Arrhenius plot for water exchange is linear over the range of 3 degrees - 37 degrees C and th Arrhenius activation energy is 4.79 +/- 0.03 kcal (SE). This value does not differ significantly from the energy required for bulk water flow. Results are compared with previous determinations, and sources of systematic error in tau a and the activation energy are evaluated.

Body Water↗
PubMed1979

Tissue response to the Fadenoperation.

The Fadenoperation was performed on 24 rabbit eyes. In 8 eyes the globe and muscle were removed intact and in 16 eyes the muscle was dissected from the sclera to determine the site and degree of attachment. The greatest degree of adherence was found between the muscle and the sclera at the site of the suture, less attachment at the lateral and medial border of the muscle, less in the central area close to the suture site, and least in the central anterior area. The Fadenoperation creates adherence of the muscle to the sclera. Its clinical usefulness will, however, depend on clinical evaluation.

Animals↗
PubMed1978

Management of large angle exotropia.

Four cases of large angle exotropia secondary to third nerve palsy are presented. An effective technique involving recession of the lateral rectus and splitting and advancement of the medial rectus is presented.

Adolescent↗
PubMed1976

Vitreous fluidity in myopia.

Forth-eight eyes were examined to determine if degeneration and liquification of the vitreous could be determined by vitreous movement in subjects with myopia compared with subjects who had either emmetropia or hypermetropia. The difference in duration of vitreous movement for the myopes was significantly greater than that for nonmyopes (p less than 0.05).

Adult↗
PubMed1976

The disposition and pharmacokinetics in humans of 5-azacytidine administered intravenously as a bolus or by continuous infusion.

The disposition of 5-[4-14C]azacytidine, administered i.v. as a bolus or continuous infusion, was studied in cancer patients. After bolus, plasma 14C levels exhibited as multiphasic disappearance pattern; half-life (t1/2, beta phase) = 3.4 to 6.2 hr. Of 14C in plasma, less than 2% was associated with 5-[4-14C]azacytidine 30 min after dose. The ratios of 14C levels were: red cells/plasma, approximately 0.8; leukocytes/plasma, 1.1 to 2.3; nucleic acids/leukocytes, 0.2 to 0.43; sputum/plasma, 0.05 to 0.17. Urinary excretion (3 days) accounted for 73 to 98% of 14C, LEss than 1% in feces. The relative concentration of 5-azacytidine in plasma with continuous infusion stayed higher than with bolus; urinary excretion was similar. Fewer side effects were observed with continuous infusion than with bolus. The stability of 5-azacytidine was determined in various media at several temperatures by thin layer chromatography and nuclear magnetic resonance. At 20 degrees in Ringer's lactate (pH 6.2), the t1/2 was 94 to 100 hr. Stability increased with lowering of temperature and pH. From our data we conclude that 5-azacytidine should be given by continuous infusion rather than as a bolus.

Azacitidine↗
PubMed1975

Escalation of aggression: experimental studies.

A finding commonly obtained in research using the Buss "aggression machine" is a main effect for trail blocks, indicating an escalation in shock intensity over trails. Theoretical explanations for this effect were tested in a modified verbal operant-conditioning situation. In Experiment 1, subjects could administer any of 10 levels of positive reinforcement to a "learner" for correct verbal responses or any of 10 levels of negative reinforcement to a learner for incorrect responses. Half of the subjects were required to begin with weak, half with strong, reinforcements. Results indicated that, regardless of condition, subjects gave more intense reinforcements as the learning trails progressed. Those who administered negative reinforcements devalued the learner relative to those who administered positive reinforcements. In Experiment 2, a role-playing procedure was used in which subjects administered either positive or negative reinforcements to a learner whose performance either did or did not improve over trials. Again, in all experimental groups, subjects administered increasingly intense reinforcements over trials. The results are interpreted as supporting a disinhibition theory of anti- and prosocial behavior.

Aggression↗