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Biomedical subjects

R Deutsch

Publications and source records attributed to R Deutsch.

32 records · Page 2Linked to original sources
PubMed1985

Nanosecond optical spectra of iron-cobalt hybrid hemoglobins: geminate recombination, conformational changes, and intersubunit communication.

Hybrid hemoglobins were prepared in which cobalt was substituted for the heme iron in either the alpha or beta subunits. Transient optical absorption spectra were measured at room temperature for these hybrids at time intervals between 0 and 50 ms following photodissociation of the carbon monoxide complex with 10-ns laser pulses. The cobalt porphyrins do not bind carbon monoxide, making it possible to investigate the time-resolved response of the cobalt-containing subunits to photodissociation of carbon monoxide in the iron-containing subunits. At the same time the response of the iron-containing subunits to the photolysis event can be studied, permitting an independent determination of the kinetics of ligand rebinding and conformational changes in the alpha and beta subunits of an intact tetramer. The data were analyzed by using singular-value decomposition to obtain the kinetic progress curve for ligand rebinding, the deoxyheme and cobalt porphyrin spectral changes, and the time course of these spectral changes. The geminate rebinding kinetics following photodissociation of alpha(Co)2 beta(Fe-CO)2 were very similar to those found unsubstituted hemoglobin, alpha(Fe-CO)2 beta(Fe-CO)2, indicating equivalence of the geminate kinetics for alpha and beta subunits within the R-state tetramer. The results for alpha(Fe-CO)2 beta(Co)2 were consistent with this conclusion, even though the analysis was complicated by the presence of comparable populations of R- and T-state species. Comparison of the deoxyheme spectral changes and relaxation times among the three molecules indicated that both alpha and beta subunits contribute to the deoxyheme spectral changes that signal tertiary and quaternary conformational changes in the unsubstituted tetramer. The response of the cobalt porphyrins to photodissociation was similar in the two hybrids. No structural changes were detected in the cobalt-containing subunits until the second tertiary conformational change in the iron-containing subunits observed at 1-2 microseconds. Much larger structural changes, as judged by the amplitude of the spectral changes, occurred in the cobalt-containing subunits concomitant with the R----T quaternary change at about 20 microseconds.

Cobalt↗
PubMed1984

The effect of diazepam on a conditioned emotional response in the rat.

Benzodiazepines have been shown to stimulate appetite and to affect behaviour in experimental situations that are viewed as providing a model of anxiety. However, the "anti-anxiety" effect is normally demonstrated in situations that use food to motivate behaviour. In the present research, the effect of diazepam was tested on the suppression of drinking brought about by a tone that had been previously paired with shock. Diazepam produced a marked decrease in the amount of time it took the animal to resume drinking, thus providing support for the anti-anxiety effect. Both acute and chronic modes of administration were effective, but the effect was even more clear-cut with chronic administration.

Animals↗
PubMed1983

[Not Available].

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Historiography↗
PubMed1978

Effects of atropine on conditioned taste aversion.

Atropine sulfate, which has a deleterious effect on various learning tasks, was found to have a similar effect on the acquisition of conditioned taste aversion. Thus, intraperitoneal injection of atropine sulfate shortly before tasting was found to interfere with conditioning of the aversion, but injection of atropine after tasting did not. The interference effect was also obtained with intraventricular administration of atropine sulfate, but not with intraperitoneal injection of the peripherally-acting atropine methylnitrate. These results show that central rather than peripheral mechanisms are involved in this effect, and suggest that conditioned taste aversion, like other kinds of learning, involves cholinergic mediation.

Animals↗
PubMed1977

Phenethyl alcohol inhibition of sn-glycerol 3-phosphate acylation in Escherichia coli.

In vivo and in vitro experiments were performed to determine how phenethyl alcohol (PEA) inhibits phospholipid synthesis in Escherichia coli. This drug drastically reduced the rate of incorporation of sn-glycerol 3-phosphate into the phospholipids of an sn-glycerol 3-phosphate auxotroph. PEA also reduced the rate of fatty acid incorporation into the phospholipids of a fatty acid auxotroph. The kinetics of PEA inhibition of the rate of incorporation of sn-glycerol 3-phosphate were almost identical to those of PEA inhibition of the rate of fatty acid incorporation into phospholipids. The in vivo experiments suggested that the rate-limiting step(s) in phospholipid biosynthesis inhibited by PEA is at the level of the acylation of sn-glycerol 3-phosphate or beyond this step. PEA inhibited the sn-glycerol 3-phosphate acyltransferase with either palmitoyl coenzyme A or palmitoyl-acyl carrier protein as the acyl donor. This drug, however, had no effect on the cytidine 5'-diphosphate-diglyceride:glycerol 3-phosphate phosphatidyl transferase, cytidine 5'-diphosphate-diglyceride:L-serine phosphatidyl transferase, and acyl coenzyme A:lysophatidic acid acyltransferase. The in vitro findings suggested that PEA inhibits phospholipid synthesis primarily at the level of sn-glycerol 3-phosphate acyltransferase.

Acylation↗
PubMed1975

Eye movement in perception of another person's looking behavior.

Eye contact is a non-verbal behavior category of major concern in the study of social interaction. Within this category many behaviors are included which serve a wide range of functions. It was hypothesied that (1) one of the important stimulus properties that distinguish these behaviors is the movement pattern of the eye and (2) that people use different criteria to judge whether another person is looking at them, depending upon whether the other person is displaying a dynamic or static eye presentation. Data are presented to support these hypotheses.

Eye Movements↗
PubMedDate not supplied

Ethnic differences in analgesic consumption for postoperative pain.

OBJECTIVE: To examine the influence of patient ethnicity on receipt of postoperative analgesia. METHOD: Chart review of 250 consecutive patients hospitalized for open reduction and internal fixation of a limb fracture. Analgesics consumption in the postoperative period was measured in terms of morphine equivalents. RESULTS: There were significant differences (p < .005) in analgesics administered to black, Hispanic, and white patients. Whites received 22 mg/day, blacks 16 mg/day, and Hispanics 13 mg/day. These ethnic differences persisted after controlling for possible confounding variables. CONCLUSION: Ethnicity exerts a powerful impact on medical care. We cannot determine from our data whether these differences stem from differences in pain behavior of the patients or differences in medical staff's perception and treatment of such patients.

Adult↗
PubMedDate not supplied

The influence of HIV-related support groups on survival in women who lived with HIV. A pilot study.

To determine the effect of support groups on survival, the authors retrospectively studied 21 HIV-seropositive women who died during the course of participation in a natural history study of HIV. Groups were composed of women who self-selected HIV support groups before death (n = 11) and a comparison group (n = 10). Survival analysis found group participation to be associated with increased longevity (73 months vs. 45 months; P = 0.011). Proportional-hazards regression demonstrated that HIV-related support groups and smaller family size significantly influenced survival (P = 0.0002). Factors related to group participation and ways in which support groups might promote longevity are discussed.

Adaptation, Psychological↗