A cholera toxin-sensitive guanyl nucleotide binding protein mediates the movement of pituitary luteinizing hormone into a releasable pool: loss of this event is associated with the onset of homologous desensitization to gonadotropin-releasing hormone

Cholera toxin (CTX; 5 micrograms/ml), but not pertussis toxin (100 ng/ml), when preincubated with pituitary cells for 18 h, enhances the percentage of cellular LH released in response to continuous or pulsatile administration of 5 x 10(-9) M GnRH. This effect occurs without increasing total (intracellular plus extracellular) LH, indicating that it is best explained by redistribution of LH from a nonreleasable to a releasable pool. This site of action is consistent with the observation that CTX-pretreated cells are also sensitized to stimulation of LH release by the Ca2+ ionophore A23187. The observations that CTX stimulates the production of cAMP in these cells and that the sensitizing action of CTX is mimicked by (Bu)2cAMP (1 mM) are consistent with the view that a CTX-stimulated guanyl nucleotide binding protein, capable of activating adenylyl cyclase, is mediating this sensitization. We used a perifused cell system to show that the movement of LH into a releasable pool is lost with the onset of homologous desensitization due to high pulse frequency or constant administration of GnRH (5 x 10(-9) M, continuous or a pulse each 15 min). Sensitization to CTX is restored by stimulation with a high concentration of GnRH (10(-6) M) or by resetting the pulse frequency to the rate measured in vivo (a pulse each 90 min). Both of these treatments also circumvent the desensitized state, restoring LH release. These results identify a novel lesion associated with the development of desensitization in the gonadotrope and support the role of a CTX-sensitive guanyl nucleotide binding protein in regulation of pituitary responsiveness to GnRH.     

The likelihood of violent behaviour: Predictions, postdictions, and hindsight bias.

Studied the effects of variations in base rate (BR) information and temporal context on predictions of violence and hindsight bias (HB). 270 undergraduates estimated the likelihood of violent offenders committing another violent offense based upon fictitious case history information. Ss were given 1 of 2 population BRs of the likelihood of reoffending (30% or 70%) and a recidivism estimation question that was phrased either predictively, predictively with a given outcome of either recidivism or no recidivism, or postdictively. Although different offenders were perceived as differentially likely to reoffend, estimated likelihood of recidivism was affected by neither BR nor temporal phrasing of the estimation task. A 2nd study of 182 undergraduates, using shorter case histories, also found no BR effect. HB effects were weak and inconsistent in both studies. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequence-specific methylation of the mouse H19 gene in embryonic cells deficient in the Dnmt-1 gene

Currently, the pig species is regarded as the most likely organ donor for human xenotransplantation in the future. However, it cannot be granted that the pig will be the optimal species of choice. We have studied human anti-sheep antibodies in comparison with anti-pig antibodies. The anti-sheep lymphocytotoxic and hemagglutination titers were in the range 8 to 128 and 2 to 32, respectively, in single individuals, which were considerably lower than the anti-pig titers of these individuals. Perfusion of sheep kidneys with human blood reduced the anti-sheep xenoantibody titers to zero as measured by lymphocytotoxic, hemagglutination, and sheep aortic endothelial cell antibody binding assays. The perfused kidneys showed generalised depositions of human IgM and C3c in the vascular tree and focal depositions of C1q and fibrin. Obliteration of capillaries by human platelets and polymorphonuclear cells were observed. Total neutral glycolipid fractions were isolated from sheep intestinal, pancreatic, and kidney tissues. By using a chromatogram binding assay, a monoclonal anti-Forssman antibody identified a single compound with five sugar residues in all organs. Several glycolipid bands were stained in all organs by the Gal(alpha)1-specific lectin I-B4 from Griffonia (Bandeiraea) Simplicifolia. A human AB serum pool showed staining by both IgG and IgM antibodies of the Forssman and Gal(alpha)1-terminating components as well as some other, not structurally identified, components. The Forssman and Gal(alpha)1-reactivity in human sera could be eliminated by immunoadsorption using Forssman and Gal(alpha)1-3Gal-immunoadsorbent columns, respectively. Immunostaining of sheep kidney tissue sections showed the presence of Gal(alpha)1-terminating epitopes by immunoperoxidase and immunogold silver staining techniques. Proximal convoluted tubules showed a strong staining, while thin loops of Henle, collecting ducts, urothelium, and vessels showed a weaker staining. Distal convoluted tubules and thick loops of Henle were completely negative. In summary, human serum contains anti-sheep xenoantibodies reacting mainly with the Forssman and Gal(alpha)1-determinants in sheep tissues and the anti-sheep antibody titers are lower than the corresponding anti-pig titers.     

Complex radiation diagnosis of retroperitoneal tumors and tumor-like states

The paper presents the results of complex radiation diagnosis of 118 cases of retroperitoneal tumors and tumor-like states, including 71 patients with tumors of mesenchymal origin, 7 with those of neurogenic origin, 6 with cysts, 9 with lymphogranulomatosis, 8 with retroperitoneal fibrosis, 12 with metastases, and 5 with hematomas. A wide complex of routine and up-to-date high-technology radiation diagnostic techniques was used to study the patients. The authors show the merits and dismerits of each technique. Greatest attention is given to the assessment of current techniques, primarily to ultrasonography (US) and computed tomography (CT). The studies have indicated that despite some specific features, many retroperitoneal tumors and tumor-like states bear similarities when various radiation methods are employed. The authors describe some syndromes which can be used to make a diagnosis. Despite the high capacities of US and CT in studying the normal and pathological structures of the human body, there are still great difficulties in differentiating different abnormalities when even the latest techniques are applied, these cases need paracentic aspiration or open biopsy.     

Inheritance of male hybrid sterility in the house musk shrew (Suncus murinus, Insectivora, Soricidae)

Two geographic races of the house musk shrew (Suncus murinus) were crossed and intercrossed in the laboratory. Many cases of male sterility were detected among the hybrids. Segregation analysis of the pedigree data showed that the inheritance of male sterility in interracial hybrids of S. murinus can be described within the framework of monogene polyallele model with sterility of a single allele combination. This model is similar if not identical to that proposed by Dobzhansky and Muller.     

Surgical treatment of cyclosporine A- and nifedipine-induced gingival enlargement: gingivectomy versus periodontal flap

The purpose of this study was to compare probing depth resolution achieved by gingivectomy and periodontal flap techniques in the treatment of cyclosporine A- and nifedipine-induced gingival enlargement. Ten kidney transplant patients who were receiving cyclosporine A and nifedipine for at least 6 months participated in the study. Five patients were randomly assigned to the gingivectomy group and 5 patients to the periodontal flap group. Only anterior segments of the oral cavity (canine to canine) were surgically treated. Clinical measurements, including probing depths, plaque index, and gingival sulcus index, were taken at baseline, 6 weeks, 6 months, and 1 year. Results showed that probing depths, while similar for both groups in the first 6 weeks of the study, were significantly shallower for the periodontal flap group when compared to the gingivectomy group at 6 months (2.48 +/- 0.34 mm versus 4.87 +/- 0.79 mm, respectively) and 1 year (322 +/- 0.65 mm versus 6.40 +/- 1.02 mm, respectively). Within its limitations, this study suggests that the pocket reduction achieved by the periodontal flap may be sustained for longer periods of time than by the gingivectomy technique in the treatment of cyclosporine A- and nifedipine-induced gingival enlargement.     

Aortopulmonary fistula in an infected Dacron graft for coarctation of the aorta: an uncommon cause of hemoptysis

Hemoptysis secondary to an aortobronchial fistula is rare and uniformly fatal when left untreated. The authors describe a case of massive hemoptysis caused by an aortopulmonary fistula in an infected Dacron graft used successfully to repair a coarctation of the aorta.     

Fundamental dynamics of flow through carbon nanotube membranes

The flow of a model non-polar liquid through small carbon nanotubes is studied using non-equilibrium molecular dynamics simulation. We explain how a membrane of small-diameter nanotubes can transport this liquid faster than a membrane consisting of larger-diameter nanotubes. This effect is shown to be back-pressure dependent, and the reasons for this are explored. The flow through the very smallest nanotubes is shown to depend strongly on the depth of the potential inside, suggesting atomic separation can be based on carbon interaction strength as well as physical size. Finally, we demonstrate how increasing the back-pressure can counter-intuitively result in lower exit velocities from a nanotube. Such studies are crucial for optimisation of nanotube membranes.