Chronic vascular access for repeated blood sampling in the unrestrained rat.
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Animals↗
Biomedical subjects
K Snyder
Publications and source records attributed to K Snyder.
Lithium ion transport by erythrocytes of randomly selected blood donors and manic-depressive patients: lack of association with affective illness.
The authors measured the in vitro lithium ion ratio and maximal rate of sodium-lithium countertransport in erythrocytes of 739 randomly selected blood donors and 42 manic-depressive patients to determine the frequency distributions of these two variables in a general population and their relationship to one another and to affective illness. A large interindividual variation was found for the ratio and countertransport, and there was evidence of bimodality in the frequency distributions for these two traits. There was a moderate negative correlation (r = -.61) between the ratio and countertransport for 126 individuals. Neither the ratio nor countertransport was found to be a useful marker for affective illness.
Adult↗
Behavioral recovery associated with central nervous system regeneration in the snail Melampus.
The pulmonate snail Melampus bidentatus regenerates central nervous tracts following commissurotomy, connective transection, and cerebral ganglion ablation. Our goal was to determine whether or not neural regrowth within the central nervous system restored behaviors disrupted by lesions. One behavior that is disrupted by commissurotomy is retraction of facial structures that are contralateral to a stimulated facial region, a response that normally accompanies the ipsilateral retraction. Tentacle withdrawal on the side contralateral to stimulation reappeared on a timescale that was correlated with growth of a commissural link (8-19 days post-lesion). Electrophysiological recordings from a labial nerve pathway that has a contralateral component similar to the contralateral tentacle response showed that development or strengthening of an alternative pathway could also mediate contralateral responses. Thus, a major conclusion of this study was that both tract regeneration and changes in existing CNS pathways can underlie recovery. The percentage (approx. 75%) of snails that regenerate the cerebral commissure and show behavioral recovery is established early in the period following commissure transection. Behavioral recovery and anatomical evidence of regeneration were also correlated in the other two operations: single cerebral ganglion removal and unilateral cerebropleural and cerebropedal connective transection. We conclude that Melampus is able to regenerate neuronal connectivity that can restore normal behavior.
Animals↗
Life events, familial stress, and coping in the developmental course of schizophrenia.
Recent studies have isolated some socioenvironmental factors that seem to predict the onset of schizophrenic episodes in vulnerable persons. In particular, stressful life events have been found to cluster in the 3- to 4- week period preceding a schizophrenic episode in some patients. Many persons with a schizophrenic disorder also seem to contribute to additional stressful life change events--for example, by high geographic mobility--thereby playing an active role in precipitating the onset of illness episodes. Within the family environment, hostile, critical, and emotionally overinvolved attitudes toward the patient by relatives have been found to be related to relapses. Irregularities in the communication style of parents also predict the subsequent development of schizophrenia spectrum disorders among disturbed adolescents. Many schizophrenic patients also seem to be deficient in the coping skills required to remediate the losses brought on by life events or to deal effectively with stressful relatives. Thus, they may experience greater and more prolonged stress than most others due partially to inadequate social and problem-solving skills and less supportive social networks. These findings have important implications for the design of clinical interventions as well as the development of a comprehensive vulnerability/stress model for the course of schizophrenic disorders.
Adaptation, Psychological↗
The dexamethasone suppression test in normal control subjects: comparison of two assays and effect of age.
he authors used competitive protein binding assay and radioimmunoassay to measure cortisol levels in 38 normal control subjects three times before and three times after administration of 1 mg of dexamethasone. They found significant interassay differences at 11:00 p.m. before dexamethasone and at all three postdexamethasone times. Analysis of variance revealed significant overall positive relationships between age and cortisol levels measured by both techniques. Age correlated significantly with postdexamethasone cortisol levels measured by radioimmunoassay but not when measured by competitive protein binding assay. Clinicians should obtain data from their laboratories as to appropriate cutoffs for cortisol suppression on the specific assay used.
Adult↗
Chronic pericarditis due to a streptomyces species.
Streptomyces species include a group of aerobic actinomycetes that are generally considered to be saprophytes. Effusoconstrictive pericarditis of mixed etiology developed in a previously healthy patient. The cause of the chronic pericarditis was a Streptomyces species.
Adult↗
Alternative cost-effective anesthesia care teams.
Private and public payers are increasingly seeking an overall per-diem or global surgery rates that put hospitals at significant financial risk for anesthesia services. Other payers are demanding deep discounts in anesthesia fees and negotiating global capitation rates that put both hospitals and physicians at risk for all care including anesthesia. This study examines some of the various organizational models for using physician anesthesiologist (MDA) and nurse anesthetist (CRNA) resources most cost effectively and safely. Variations in percentages of these practitioners can be seen in that California reportedly has 47 MDAs for every 10 CRNAs while Michigan has just 6 MDAs for every 10 CRNAs practicing in that more highly managed care environment. Four various anesthesia practice models are described in detail without declaring any one a universal model. The cost per year for MDAs averages $294,000 while the cost per year for CRNAs is less than half as much.
Anesthesiology↗