A mixture of ammonium perchlorate and sodium chlorate enhances alterations of the pituitary-thyroid axis caused by the individual chemicals in adult male F344 rats

Ammonium perchlorate (AP) and sodium chlorate (SC) have been detected in public drinking water supplies in many parts of the United States. These chemicals cause perturbations in pituitary-thyroid homeostasis in animals by competitively inhibiting iodide uptake, thus hindering the synthesis of thyroglobulin and reducing circulating T(4) (thyroxine). Little is known about the short-term exposure effects of mixtures of perchlorate and chlorate. The present study investigated the potential for the response to a mixture of these chemicals on the pituitary-thyroid axis in rats to be greater than that induced by the individual chemicals. Adult male F-344 rats were exposed, via their drinking water, to the nominal concentrations of 0.1, 1.0, 10 mg/L AP or 10, 100, 1000 mg/L SC and their mixtures for 7 days. Serum T(4) levels were significantly (p < 0.05) reduced in rats following exposure to the mixtures, but not after exposure to the individual chemicals. Serum T(3) (triiodothyronine) was not altered by treatment and TSH (thyroid stimulating hormone) was only increased after the high-dose chlorate treatment. Histological examination of the thyroid gland showed colloid depletion and hypertrophy of follicular epithelial cells in high-dose single chemical and all mixture-treated rats, while hyperplasia was observed only in some of the rats treated with mixtures (AP 10 + SC 100, AP 0.1 + SC 1000, and AP 10 + SC 1000 mg/L). These data suggest that short-term exposure to the mixture of AP and SC enhances the effect of either chemical alone on the pituitary-thyroid axis in rats.     

A novel autosomal recessive non-syndromic deafness locus (DFNB35) maps to 14q24.1-14q24.3 in large consanguineous kindred from Pakistan

Autosomal recessive nonsyndromic deafness is one of the most frequent forms of inherited hearing impairment. Over 30 autosomal recessive nonsyndromic hearing loss loci have been mapped, and 15 genes have been isolated. Of the over 30 reported autosomal recessive nonsyndromic hearing loss (NSHL) loci, the typical phenotype is prelingual non-progressive severe to profound hearing loss with the exception of DFNB8, which displays postlingual onset and DFNB13, which is progressive. In this report we describe a large inbred kindred from a remote area of Pakistan, comprising six generations and segregating autosomal recessive nonsyndromic prelingual deafness. DNA samples from 24 individuals were used for genome wide screen and fine mapping. Linkage analysis indicates that in this family the NSHL locus, (DFNB35) maps to a 17.54 cM region on chromosome 14 flanked by markers D14S57 and D14S59. Examination of haplotypes reveals a region that is homozygous for 11.75 cM spanning between markers D14S588 and D14S59. A maximum two-point LOD score of 5.3 and multipoint LOD score of 7.6 was obtained at marker D14S53. The interval for DFNB35 does not overlap with the regions for DFNA9, DFNA23 or DFNB5.     

Direct comparison of umbilical cord blood versus bone marrow-derived endothelial precursor cells in mediating neovascularization in response to vascular ischemia.

Endothelial precursor cells (EPCs) cultured from adult bone marrow (BM) have been shown to mediate neovasculogenesis in murine models of vascular injury. We sought to directly compare umbilical cord blood (UCB)- and BM-derived EPC surface phenotypes and in vivo functional capacity. UCB and BM EPCs derived from mononuclear cells (MNC) were phenotyped by surface staining for expression of stromal (Stro-1, CXCR4, CD105, and CD73), endothelial (CD31, CD146, and vascular endothelial [VE]-cadherin), stem cell (CD34 and CD133), and monocyte (CD14) surface markers and analyzed by flow cytometry. The nonobese diabetic/severe combined immunodeficiency murine model of hind-limb ischemia was used to analyze the potential of MNCs and culture-derived EPCs from UCB and BM to mediate neovasculogenesis. Histologic evaluation of the in vivo studies included capillary density as a measure of neovascularization. Surface CXCR4 expression was notably higher on UCB-derived EPCs (64.29%+/-7.41%) compared with BM (19.69%+/-5.49%; P=.021). Although the 2 sources of EPCs were comparable in expression of endothelial and monocyte markers, BM-derived EPCs contained higher proportions of cells expressing stromal cell markers (CD105 and CD73). Injection of UCB- or BM-derived EPCs resulted in significantly improved perfusion as measured by laser Doppler imaging at days 7 and 14 after femoral artery ligation in nonobese diabetic/severe combined immunodeficiency mice compared with controls (P<.05). Injection of uncultured MNCs from BM or UCB showed no significant difference from control mice (P=.119; P=.177). Tissue samples harvested from the lower calf muscle at day 28 demonstrated increased capillary densities in mice receiving BM- or UCB-derived EPCs. In conclusion, we found that UCB and BM-derived EPCs differ in CXCR4 expression and stromal surface markers but mediate equivalent neovasculogenesis in vivo as measured by Doppler flow and histologic analyses.     

Marden-Walker syndrome: case report, literature review and nosologic discussion

Schrander-Stumpel C, de Die-Smulders C, de Krom M, Schyns-Fleuren S, Hamel B, Jaeken D, Fryns J-P. Marden-Walker syndrome: case report, literature review and nosologic discussion.
Clin Genet 1993: 43: 303–308. © Munksgaard, 1993
The Marden-Walker syndrome is characterized by psychomotor retardation, a mask-like face with blepharophimosis, micrognathia and a high-arched or cleft palate, low-set ears, kyphoscoliosis and joint contractures. We report on a male patient with the clinical features of the syndrome. In addition, he had a Dandy-Walker malformation with hydrocephalus and vertebral abnormalities. During pregnancy, there were feeble fetal movements and polyhydramnios. We propose that Marden-Walker syndrome is one of the etiologic possibilities in children with the heterogeneous fetal a(hypo)kinesia deformation sequence (FADS). Differential diagnosis is discussed. The etiology is probably heterogeneous.     

Stress proteins as inducers and targets of regulatory T cells in arthritis

Immunization with microbial or mammalian stress proteins or heat-shock proteins in models of experimental autoimmunity has been observed to lead to increased disease resistance. Furthermore, such immunization has been proposed to result in the induction and expansion of T cells that suppress disease upon transfer. Comparisons of microbial heat-shock proteins with other conserved immunogenic proteins of bacterial origin have indicated a unique capacity for heat-shock proteins to induce a regulatory phenotype in T cells, such as reflected by the production of IL10. Also, studies in children with chronic arthritis have indicated that T-cell responses to heat-shock proteins are associated with a benign course of the disease and with remission. Furthermore, in patients, heat-shock-protein-(HSP-) activated T cells were shown to display regulatory phenotypes consistent with CD4+ CD25+ T regulatory cells.     

IgA hybridomas: A method for generation in high numbers

An immunization regimen has been developed which yields a high frequency of hybridomas producing IgA isotype, antigen-specific antibody when spleen cells from immunized mice are fused with non-immunoglobulin secreting murine myeloma cells. Germfree BALB/c mice were carrier-primed with sheep erythrocytes (SRBC) by gastric intubation (GI) for 2 consecutive days followed 1 week later by GI with trinitrophenyl (TNP)-haptenated SRBC. After 7 days, spleen cells were fused with non-immunoglobulin secreting myeloma cells (X63-Ag8.653), and 2–3 weeks later, culture wells were scored for hybrid clones. Of 240 culture wells plated, 157 wells (65.4%) exhibited clones producing anti-TNP antibodies as determined by enzyme-linked immunosorbent assay. A total of 50 specific cell lines were established, of which 27 clones (54%) produced IgA isotype anti-TNP antibodies, while the anti-TNP antibodies produced by the remaining 23 clones were approximately equally distributed between the IgM and IgG isotypes. The IgA and IgM monoclonal antibodies were more effective in hemagglutinating TNP-SRBC than were IgG isotype antibodies. This study describes a method for production of a high number of antigen-specific IgA hybridomas which will allow production of IgA monoclonal antibodies to important antigens on mucosally-associated pathogens, and thus allow elucidation of functions of IgA antibody at mucosal surfaces.     

Localization of IFN-gamma-activated Stat1 and IFN regulatory factors 1 and 2 in breast cancer cells.

The aim of the present work was to evaluate the induction and localization of Stat1, interferon (IFN) regulatory factor-1 (IRF-1), and IRF-2 after IFN-gamma exposure of human breast cancer cell lines, SKBR3, MDA468, MCF7, and BT20. Results from growth assays, Western staining, electrophoretic mobility shift assay (EMSA), and immunohistochemical staining were collated to test our hypothesis that immunohistochemical analysis of Stat1, IRF-1, and IRF-2 would provide additional information about the functionality of the IFN-gamma signaling pathway in human tumor lines. EMSA results showed that in each of four cell lines, Stat1 expression was increased and demonstrated functional activity after IFN-gamma stimulation. Western and EMSA analysis showed upregulation of IRF-1 but not IRF-2 in each cell line. Confocal microscopy of cells stained for Stat1, IRF-1, and IRF-2 confirmed the results and also provided novel information about the intracellular localization of proteins and intercellular variations in responses. The proportion of cells with IRF-1 stimulation and translocation was positively correlated with the IFN-gamma growth suppression in vitro. In conclusion, using four independent assays, we have demonstrated that heterogeneity in IFN-gamma-mediated upregulation of signal transduction proteins can be detected in vitro and that these differences can explain distinct cellular growth effects.     

Video analysis of communication in paediatric consultations in primary care.

BACKGROUND: There is a paucity of research evidence concerning communication in paediatric consultations between GPs, adults, and child patients. AIM: This study was carried out to identify features of the interaction between a doctor, a child patient aged 6-12 years, and their carer in the consultation associated with the child's participation. DESIGN OF STUDY: A qualitative analysis of video recordings of 31 primary care paediatric consultations was undertaken, using strategies from the methodology of conversation analysis. SETTING: Primary care, Suffolk, UK. METHOD: NHS GPs from three primary care trusts (PCTs), were invited to participate in this study. Sixteen volunteers from this sample took part. RESULTS: Analysis of the interaction in the consultations revealed that the children had little involvement. Children participated when invited to do so, and took more time than adults to answer a doctor's question. An adult carer was less likely to answer on behalf of a child, when they were in a position to see that the doctor's gaze was directed at the child, and the doctor addressed the child by name. Adult carers, who had not voiced their own concerns first, were seen to interrupt doctor-child talk. In consultations where the participants sat in a triangular arrangement, all parties being an equal distance apart, triadic talk was noted. CONCLUSION: Child involvement in the primary care consultation is associated with adult carers being able to voice their own concerns early in the consultation, and children being invited to speak with the appropriate recipient design.