Effects of thyroidectomy, parathyroidectomy and lithium on circadian wheelrunning in rats

Circadian rhythms and levels of wheelrunning were studied in thyroidectomized, parathyroidectomized, thyro-parathyroidectomized, and sham-operated male rats. Animals were entrained to a 12:12 light:dark schedule, then exposed to constant dim red illumination, and then given a diet containing lithium. Under constant conditions, free-running circadian activity rhythms were shorter, and levels of activity were greater, in thyroidectomized and thyroparathyroidectomized animals. Lithium reversed these effects, lengthening free-running circadian periods in all groups, with a greater reduction of activity observed in animals with thyroids removed. Parathyroidectomy had no clear effects. Since lithium slowed circadian rhythms and reduced activity even in the absence of intact thyroid or parathyroid glands, these effects may have been due to the action of lithium at some other site. The same may be true of other thyroid suppressors reported to affect circadian rhythms. These findings may be relevant to the biological substrates of major affective disorders in humans, which have been associated with abnormalities of thyroid function, abnormally short circadian rhythms, abnormal activity levels, and responsiveness to lithium therapy.

Bacterial colonization of intestinal urinary conduit diversion: a morphologic and bacteriologic experimental study

Cutaneous diversion of the urine through intestinal conduits results in bacteriuria with uropathogenic organisms in up to 80% of patients, many of whom suffer pyelonephritis. Analysis of the bacteriologic data from daily sampling at multiple sites and scanning and transmission electron microscopic studies of sequential loop and autopsy specimens in rabbits with functioning colonic conduits indicate that the pyelonephritis evolves in sequential stages of microbial colonization. Using these data on the natural progression of bacterial infection, we can rationally test the ability of strains of bacteria indigenous to the conduit of this animal model to prevent uropathogenic colonization of the conduit.

An ecological study of infected urinary stone genesis in an animal model

Direct molecular and morphological techniques of modern microbiology were used to monitor the sequential development of bacterial microcolonies and biofilms in a rat model of urinary infection and to demonstrate that the urease activity of the infecting organisms sets in course a series of reactions in which struvite and apatite crystals develop within the matrix of the enlarging bacterial aggregate. This forms multiple stone nidi on the uroepithelial surface upon which succeeding bacterial biofilms develop and with the incorporation of other urine components, such as urinary mucroproteins, establishes a matrix skeleton that becomes mineralised, thus allowing for the growth of the stone in concentric layers. To arrive at this hypothesis, we studied infection stone genesis using a newly developed model for infection-induced bladder stone formation in the rat. We examined in detail the sequential events in the evolving microbial ecology of progressive struvite calculogenesis, using conventional microbiological techniques, direct ultrastructural observation, newly developed ultrastructural cytochemical localisation techniques and immunological procedures for stabilisation of the biofilm glycocalix and stone matrix in the rat model. It was concluded that the organic glycocalix material secreted by the associated bacteria comprises a substantial and aetiologically important part of the infection stone calculogenesis and matrix production.

Surgical wound infections. A 5-year prospective study of 20,193 wounds at the Minneapolis VA Medical Center

This report describes a 5-year prospective study of postoperative wound sepsis utilizing a careful program of wound surveillance. Surgical wounds following 20,193 operations on all surgical services were surveyed by a trained nurse epidemiologist. Daily examination of wounds, culture of all suspicious wounds, and 30-day outpatient clinic follow-up were performed. Results were disseminated at monthly intervals to all involved surgeons and operating room personnel. Prospective and ongoing analysis of results facilitated identification and rectification of specific problem areas. Wound infection rates demonstrated a steady decline over the course of the study, overall rates dropping from 4.2% to 1.9% (p less than 0.05). This reduction in incidence of postoperative wound sepsis of 55% is estimated to have saved 2740 inhospital days and nearly $750,000.

Hemoglobin North Shore: a variant hemoglobin associated with the phenotype of beta-thalassemia

Hemoglobin (Hb) North Shore (beta 134 val leads to glu) is a mutant hemoglobin that is associated with the phenotype of mild heterozygous beta-thalassemia. Heterozygotes are characterized low normal hemoglobin levels or mild anemia, microcytosis, increased HbA2, and 34%-38% Hb North Shore. The mechanism of the anemia and microcytosis associated with Hb North Shore was explored by studies of hemolysate thermal instability, peripheral blood globin biosynthesis, and whole blood oxygen affinity. Hb North Shore was mildly heat unstable in comparison to normal adult hemolysate. Pulse labeling of reticulocytes with 3H-leucine showed an alpha/beta ratio of 1.35 (normal 1.0). The beta North Shore/alpha ratio was 0.22-0.27, which was less than expected on the basis of gene dosage and less than that seen for most beta-chain variants. The beta A/alpha ratio was 0.50, as would be expected. The beta North Shore/alpha ratio was 0.26 after a 15-min pulse and did not decrease during 120 min of chase. These findings suggest that suboptimal synthesis rather than posttranslational degradation is responsible for the thalassemic phenotype associated with this variant hemoglobin. These observations parallel the findings in heterozygous HbE. It is not presently known whether the thalassemia phenotype is conferred by the structural mutation itself or by another mutation cis to the beta North Shore gene.

The effects of phenobarbital and diphenylhydantoin on liver function and morphology

Sixty-three children with seizure disorders receiving phenobarbital and/or diphenylhydantoin for more than 12 months had liver function tests evaluated. All 56 whose serum anticonvulsant concentrations were in the therapeutic range had elevations of their serum gamma glutamyl transpeptidase activity. Of the 11 who had elevated SGOT and SGPT concentrations initially, six had persistent transaminase abnormalities for more than 20 weeks. Liver tissue from these six patients revealed by light microscopy uniform swelling of the hepatocytes without cell necrosis, inflammation, fibrosis, or disturbance of hepatic architecture. Electron microscopy demonstrated proliferation of the smooth endoplasmic reticulum without other ultrastructural alterations. All six patients were maintained on the same dosages of PB and/or DPH, and their transaminase activities returned to normal within eight to 14 months. The clinical well being of these patients, the transient nature of their SGOT and SGPT elevations, and the absence of specific histopathology suggest that chronic treatment with PB and/or DPH does not result in hepatotoxicity but rather in enzyme induction. The data indicate that liver biopsies are not warranted in such children and that PB and DPH may be continued despite mild elevations of SGOT and SGPT, without concern for hepatic damage.

Cardiac output and contractility indices: establishing a standard in response to low-to-moderate level exercise in healthy men

Measurement by impedance cardiography (ZCG) of cardiac output and contractility indices during exercise is a recent addition to exercise testing of the cardiac patient. To provide a needed standard of normal responses to exercise at integrals of resting oxygen consumption (METS), 10 healthy men were tested. Basal oxygen consumption (1MET) under standardized conditions was measured by mass spectrometry. Over several days the subjects were exercised on a treadmill at 2METS through 6METS with monitoring of heart rate, electrocardiogram, oxygen consumption per minute (VO2) and ZCG. The exercise routine was then repeated to look for test-retest effect. Values closely approximating presently accepted basal oxygen consumptions were achieved under these standardized but practical conditions. Cardiac output during sitting, fully supported rest was slightly higher than that at 2METS on treadmill owing to higher stroke volume. From 2METS through 6METS the curvilinear mean heart rate and stroke volume were mirror images, producing a linear increase in mean cardiac output which at 6METS was 145% of basal and 160% of the 2MET value, while the contractility index increased to 217% of basal. Comparison of the 2 trials revealed no significant test-retest effect.

Social support and social adjustment: implications for mental health professionals

The general importance of an individual's support network has been recognized in the field of community mental health; yet a more detailed understanding of how a client's available social ties may contribute to his or her adjustment is presently lacking. This study used network analysis to examine differences in the social networks of mental health clients to identify factors associated with positive social adjustment. Subjects were selected from three different types of mental health programs as well as from the general population of Marion County, Oregon. Results generally revealed that subjects from the community sample more often would look to immediate family members for support. Better functioning chronic clients emphasized professional contacts, whereas more poorly adjusted chronic clients would look to friends for support. The results have implications both for understanding the nature of the support available to a client and mobilizing the support resources of the existing network of relationships to aid adjustment to community living.