Indications that the Cgamma2 homology region is not a regular domain

The Cgamma2 homology region of rabbit IgG does not behave like a domain. Thus, there is no trans-interaction between the two Cgamma2 regions; instead there is an unusual cis-interaction between Cgamma2 and Cgamma3 regions. The observations were made on the plasmin digestion products Facb (IgG minus the Cgamma3 region) and pFc' (Cgamma3 region), which did not dissociate under neutral conditions but dissociated in 3M guanidine solution (that is, cis-interaction between Cgamma2 and Cgamma3). The Facb fragment split into subunits with equal molecular weights under neutral conditions on partial reduction and alkylation (that is, lack of trans-interaction between the two Cgamma2 in the molecule).     

Islet amyloid polypeptide in patients with pancreatic cancer and diabetes

Population-based psychiatric admission rates vary across geographic areas, but reasons for this variation are unknown. Insofar as Community Mental Health Centers (CMHCs) provide outpatient services that may deter the need for hospitalization, the presence and structural characteristics of CMHCs may have an impact on a population's psychiatric admission rates. This study uses small area analysis to examine how general hospital psychiatric admission rates are associated with CMHC characteristics. Based on a survey of all CMHCs in Iowa and corresponding small area variation data, it was found that population admission rates were higher in areas closer to the CMHC and lower in outlying catchment areas, adjusting for age, sex, and urban/rural differences in populations. There was little evidence that differences in staffing and service variables influenced admission rates, although greater CMHC staff coverage by social workers and psychiatric residents was associated with lower admission rates. The results suggest that CMHCs do not lower an area's hospitalization rate, and in fact, the presence of CMHCs may promote a "supplier-induced demand" phenomenon of higher admissions.     

Brain abscess in solid organ transplant recipients receiving cyclosporine-based immunosuppression

There is currently a stark therapeutic void in the treatment of evolving stroke. Although P-selectin is rapidly expressed by hypoxic endothelial cells in vitro, the functional significance of P-selectin expression in stroke remains unexplored. In order to identify the pathophysiological consequences of P-selectin expression and to identify P-selectin blockade as a potential new approach for the treatment of stroke, experiments were performed using a murine model of focal cerebral ischemia and reperfusion. Early P-selectin expression in the postischemic cerebral cortex was demonstrated by the specific accumulation of radiolabeled anti-murine P-selectin IgG, with the increased P-selectin expression localized to the ipsilateral cerebral microvascular endothelial cells by immunohistochemistry. In experiments designed to test the functional significance of increased P-selectin expression in stroke, neutrophil accumulation in the ischemic cortex of mice expressing the P-selectin gene (PS +/+) was demonstrated to be significantly greater than that in homozygous P-selectin-null mice (PS -/-). Reduced neutrophil influx was accompanied by greater postischemic cerebral reflow (measured by laser Doppler) in the PS -/- mice. In addition, PS -/- mice demonstrated smaller infarct volumes (5-fold reduction, P<.05) and improved survival compared with PS +/+ mice (88% versus 44%, P<.05). Functional blockade of P-selectin in PS +/+ mice using a monoclonal antibody directed against murine P-selectin also improved early reflow and stroke outcome compared with control mice, with reduced cerebral infarction volumes noted even when the blocking antibody was administered after occlusion of the middle cerebral artery. These data are the first to demonstrate a pathophysiological role for P-selectin in stroke and suggest that P-selectin blockade may represent a new therapeutic target in the treatment of stroke.     

Time-dependent effects of repeated amphetamine treatment on norepinephrine in the hypothalamus and hippocampus assessed with in vivo microdialysis

The effects of repeated amphetamine (AMPH) pretreatment on norepinephrine (NE) neurotransmission in the hypothalamus and hippocampus were assessed using in vivo microdialysis. Rats were pretreated with either saline or an escalating-dose AMPH regimen (1-->10 mg/kg) over 10 consecutive days, and then were withdrawn from AMPH for either 1 day or 30 days, at which time the animals underwent two consecutive days of testing. As expected, repeated treatment with AMPH resulted in time-dependent changes in both spontaneous locomotor activity and in the psychomotor response to a subsequent challenge injection of AMPH. In addition, repeated exposure to AMPH resulted in time-dependent and regionally-specific changes in the basal concentrations of NE in dialysate, and in the NE response to an AMPH challenge. For example, AMPH pretreatment produced a persistent (at least one month) increase in the basal concentration of NE in the hippocampus, but not the hypothalamus, although the response to an AMPH challenge was altered in both structures. It is suggested that AMPH treatment produces adaptations in NE systems that far outlast the acute effects of the drug, and that these may contribute to both transient and more persistent behavioral sequelae associated with the discontinuation of chronic AMPH use.     

Hepatic hemangioma. Analysis of 103 cases. Clinical considerations and imaging methods

Hemangiomas are the most common benign vascular tumor found in the liver. In this study, 103 cases of hepatic hemangiomas were analysed in a retrospective manner. Image aspects such as those seen in ultrassonography, computed tomography, nuclear magnetic resonance and arteriography are discussed. The incidence was higher amongst the female sex, between individuals from 40 to 60 years old, which presented predominantly without symptoms (66%) and localized mainly in the right hepatic lobe (74%). The meaning of those aspects, when adopted, permits the clinicians to differentiate benign from malignant nodular lesions in the liver.     

Prospective evaluation of criteria for microbiological diagnosis of prosthetic-joint infection at revision arthroplasty. The OSIRIS Collaborative Study Group

A prospective study was performed to establish criteria for the microbiological diagnosis of prosthetic joint infection at elective revision arthroplasty. Patients were treated in a multidisciplinary unit dedicated to the management and study of musculoskeletal infection. Standard multiple samples of periprosthetic tissue were obtained at surgery, Gram stained, and cultured by direct and enrichment methods. With reference to histology as the criterion standard, sensitivities, specificities, and likelihood ratios (LRs) were calculated by using different cutoffs for the diagnosis of infection. We performed revisions on 334 patients over a 17-month period, of whom 297 were evaluable. The remaining 37 were excluded because histology results were unavailable or could not be interpreted due to underlying inflammatory joint disease. There were 41 infections, with only 65% of all samples sent from infected patients being culture positive, suggesting low numbers of bacteria in the samples taken. The isolation of an indistinguishable microorganism from three or more independent specimens was highly predictive of infection (sensitivity, 65%; specificity, 99.6%; LR, 168.6), while Gram staining was less useful (sensitivity, 12%; specificity, 98%; LR, 10). A simple mathematical model was developed to predict the performance of the diagnostic test. We recommend that five or six specimens be sent, that the cutoff for a definite diagnosis of infection be three or more operative specimens that yield an indistinguishable organism, and that because of its low level of sensitivity, Gram staining should be abandoned as a diagnostic tool at elective revision arthroplasty.