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Biomedical subjects

M M Clark

Publications and source records attributed to M M Clark.

At least 91 records · Page 5Linked to original sources
PubMed1985

Measures of growth, development, and sexual maturation in mongolian gerbils (Meriones unguiculatus): effects of photic period during ontogeny.

We examined, in Mongolian gerbils, the adequacy of two commonly used indices of rate of development, age at eye-opening and age at vaginal introitus, as predictors of biologically important events: initiation of feeding on solid food and age at first parturition. We then enquired as to the interrelationships among body weight, eye-opening, and vaginal introitus in Mongolian gerbils whose rates of development were manipulated by altering the extent of their exposure to illumination during ontogeny. We found that (1) age at vaginal introitus was significantly, but weakly, correlated with age at first parturition (Experiment I); (2) age at eye-opening strongly predicted age of initiation of gnawing on solid food (Experiment II); (3) eye-opening occurred at markedly different ages, but at the same body weight in gerbils reared under 0/24-, 6/18-, 12/12-, and 24/0-hr day-night cycles (Experiment III); and (4) vaginal introitus occurred at both different ages and different body weights in females reared under different day-night cycles (Experiment III).

Animals↗
PubMed1984

The effectiveness of assertive training with elderly psychiatric outpatients.

The usefulness of assertive training for elderly psychiatric outpatients was assessed through a quasi-experimental evaluation of a program at a community geriatric facility. Elderly clients are frequently labeled as "untreatable" and are therefore often denied therapeutic treatment. This study is an example of the potential effectiveness of applying treatment techniques which have been developed with younger populations to a geriatric population. Nineteen clients, aged 50-75, participated in the study, either as participants in the assertion training or as members of a no-treatment control group. The assertion training consisted of 14 semi-weekly sessions, with coaching and feedback provided by the therapists. Assertive behaviors were assessed through self-report, role play and staff ratings of adaptive behaviors of clients. Pre-intervention comparisons between the groups along these dimensions were nonsignificant. However, post-test assessment indicated a significant between group difference in self-reported assertiveness-(t(17) = 2.69; p less than .05). Dependent t-tests indicated that the experimental group became more assertive (t(9) = 2.59; p less than .05), but the control group did not. Changes as assessed by role play and staff rating did not reach statistical significance. Results which indicate the potential effectiveness of assertive training with this population are discussed in terms of a specificity conceptualization of assertiveness and implications for assertive training with this population.

Aged↗
PubMed1983

Etomidate infusion in thoracic anaesthesia.

An etomidate infusion was used in the place of nitrous oxide during one lung anaesthesia for 40 patients undergoing thoracic surgery. Analgesia was provided by fentanyl. A mixture of oxygen and air was used to maintain arterial oxygen tension within normal limits despite one lung anaesthesia and enabled the use of nitrous oxide to be avoided in several patients who had lung cysts. Recovery was fairly rapid (mean (SEM) 11.5 (1.4) minutes). There was no incidence of awareness or dreams. This technique provides satisfactory anaesthesia and oxygenation during thoracic surgery when one lung only is being ventilated.

Adult↗
PubMed1982

Environmental effects on the ontogeny of exploratory and escape behaviors of Mongolian gerbils.

Mongolian gerbils reared in standard laboratory cages and gerbils reared in cages containing a burrowlike shelter did not differ in their rate of development of escape responses to sudden visual stimulation. The presence of shelter in the rearing environment did, however, markedly slow the development of adult-like patterns of exploration. Reduced exposure to illumination, experienced by shelter-reared subjects, proved responsible for this retardation of development. The effect of shelter-rearing on the development of exploratory behavior is interpreted as demonstrating an environmentally induced maintenance of an adaptive juvenile pattern of behavior.

Aging↗
PubMed1982

Investigation of the relationship between heat loss and nitrogen excretion in elderly patients undergoing major abdominal surgery under general anaesthetic.

An attempt was made to reduce heat loss in elderly patients undergoing major abdominal surgery. Two groups were studied. In one group, efforts were made to minimize heat loss by using a hot-water humidifier in the anaesthetic circuit, a hot-water circulating mattress under the patient and warming all i.v. fluids. Otherwise, the surgical and anaesthetic techniques were comparable. The same anaesthetic technique of nitrous oxide, oxygen, pancuronium and fentanyl with intermittent positive pressure ventilation was used in all cases. Nitrogen loss was measured in urine collected over 48 h from an indwelling urinary catheter inserted soon after induction of anaesthesia. Prevention of heat loss during anaesthesia and postoperative recovery caused a significant reduction in nitrogen loss.

Abdomen↗
PubMed1980

Effects of rearing environment on adrenal weights, sexual development, and behavior in gerbils: an examination of Richter's domestication hypothesis.

Mongolian gerbils (Meriones unguiculatus) reared and maintained in standard laboratory cages exhibited accelerated eye opening, more rapid growth, earlier sexual maturity, and marked reduction in adrenal gland size in comparison with gerbils reared in more natural cages providing access to shelter. Gerbils reared in standard laboratory cages were also easier to handle and less responsive to sudden stimulation than those reared in sheltered cages. Changes in phenotype resulting from rearing in environments lacking shelter parallel changes in phenotype resulting from the domestication process. The implications of the data for genetically oriented hypotheses of domestication are discussed.

Adrenal Glands↗
PubMed1976

Gender and sexual experience as determinants in a sexual behavior hierarchy.

The present study sought to assess the influence of gender and previous sexual experience regarding the structure of the basic sexual behavior hierarchy. Results indicated that both gender and previous experience have significant effects. Overall, gender appeared to have a less substantial effect than previous experience, being more noteworthy for the similarities manifest between males and females than the few differences observed. Previous experience displayed a substantial effect, particularly in the upper portion of the hierarchy, with like-experienced groups showing marked similarity in their hierarchy patterns. Several significant gender-experience interactions were found regarding oral-genital behaviors, and a general trend was observed for females indicating negative appreciation from pre to postexperience. Males revealed positive appreciation from pre to postexperience on all but the most basic sexual behaviors. Conclusions were to the effect that while both variables influenced the hierarchy, effects were complex, and often mediated by additional factors.

Adolescent↗
PubMed1975

Human prothrombin activation.

Human prothrombin has been purified from American Red Cross Factor IX concentrates. Studies of the activation of the human prothrombin with the use of sodium dodecyl sulfate electrophoretic analysis of activation products indicated that human prothrombin activation is similar to bovine prothrombin activation. Molecular weight analysis of human prothrombin and intermediated by sodium dodecyl sulfate co-electrophoresis with bovine prothrombin and its intermediates resulted in molecular weights of 70,000 for prothrombin, 51,000 for intermediate 1, 41,000 for intermediate 2, 23,000 for intermediate 3, and 13,000 for intermediate 4. Amino acid compositions of human prothrombin and intermediates are similar to those for bovine prothrombin and intermediates. NH2-terminal sequence studies of human prothrombin, intermediates, and alpha-thrombin A and B chains placed the intermediates in the parent human prothrombin molecule as described for the bovine system. Intermediate 3 is the NH2-terminal of prothrombin, and intermediate 1 is the COOH-terminal segment of the zymogen. Intermediate 4 is the NH2-terminal of intermediate 1. Intermediate 2', the immediate precursor of alpha-thrombin, is the COOH-terminal segment of intermediate 1. In general, a high degree of homology in the primary structure of prothrombin and intermediates was observed between the human and bovine system. The NH2-terminal sequences of human intermediate 2' and alpha-thrombin A chain are identical. However, human intermediate 2' isolated in a manner identical with that used for the isolation of bovine intermediate 2 is homologous with bovine intermediate 2, beginning with residue 14.

Amino Acid Sequence↗