Human and mouse microglia express connexin36, and functional gap junctions are formed between rodent microglia and neurons.

Microglia, the tissue macrophages of the central nervous system (CNS), intimately interact with neurons physically and through soluble factors that can affect microglial activation state and neuronal survival and physiology. We report here a new mechanism of interaction between these cells, provided by the formation of gap junctions composed of connexin (Cx) 36. Among eight Cxs tested, expression of Cx36 mRNA and protein was found in microglial cultures prepared from human and mouse, and Cx45 mRNA was found in mouse microglial cultures. Electrophysiological measurements found coupling between one-third of human or mouse microglial pairs that averaged below 30 pico-Siemens and displayed electrical properties consistent with Cx36 gap junctions. Importantly, similar frequency of low-strength electrical coupling was also obtained between microglia and neurons in cocultures prepared from neocortical or hippocampal rodent tissue. Lucifer yellow dye coupling between neurons and microglia was observed in 4% of pairs tested, consistent with the low strength and incidence of electrical coupling. Cx36 expression level and/or the degree of coupling between microglia did not significantly change in the presence of activating agents, including lipopolysaccharide, granulocyte-macrophage colony-stimulating factor, interferon-gamma, and tumor necrosis factor-alpha, except for some reduction of Cx36 protein when exposed to the latter two agents. Our findings that intercellular coupling occurs between neuronal and microglial populations through Cx36 gap junctions have potentially important implications for normal neural physiology and microglial responses in neuronopathology in the mammalian CNS.

Candidate gene region for polycystic ovary syndrome on chromosome 19p13.2.

CONTEXT: Polycystic ovary syndrome (PCOS) is a common endocrine disorder that is believed to have a genetic basis. However, no specific susceptibility gene or region has been conclusively identified. OBJECTIVE: The objective of this study was to duplicate a previous study that localized a PCOS susceptibility region to chromosome 19p13.2 and to narrow the susceptibility region. DESIGN: This study was designed to test for genetic linkage and association between PCOS and short tandem repeat polymorphisms in 367 families, by analysis of linkage and family-based association. SETTING: The study was conducted at academic medical centers. PATIENTS OR OTHER PARTICIPANTS: We studied 367 families of predominantly European origin with at least one PCOS patient. Families included 107 affected sibling (sister) pairs (ASPs) in 83 families, and 390 trios with both parents and an affected daughter. The data set comprises two independent groups. Set 1 consists of 44 ASPs and 163 trios. Set 2 consists of 63 ASPs and 227 trios. INTERVENTION(S): The intervention was the drawing of blood for DNA extraction. MAIN OUTCOME MEASURE: We employed measures of evidence for linkage and association between PCOS and 19 STRs. RESULTS: Linkage with PCOS was observed over a broad region of chromosome 19p13.2. The strongest evidence for association was observed with D19S884 (chi2 = 11.85; nominal P < 0.0006; permutation P = 0.034) and duplicated our earlier findings. CONCLUSIONS: The present analysis suggests that a PCOS susceptibility locus maps very close to D19S884. Additional studies that systematically characterize DNA sequence variation in the immediate area of D19S884 are required to identify the PCOS susceptibility variant.

Molecular genetic delineation of a deletion of chromosome 13q12-->q13 in a patient with autism and auditory processing deficits.

In a sporadic case of autism and language deficit due to auditory processing defects, molecular genetic studies revealed that a chromosomal deletion occurred in the 13q12-->q13 region. No chromosome abnormalities were detected in the parents. We determined that the deletion occurred on the paternally derived chromosome 13. There are two previous reports of chromosome 13 abnormalities in patients with autism. The deletion in the subject described in this paper maps between the two chromosome 13 linkage peaks described by Bradford et al. (2001) in studies of subjects with autism and language deficits. The 9-Mb region deleted in the patient described here contains at least four genes that are expressed in brain and that play a role in brain development. They are NBEA, MAB21L1, DCAMKL1 and MADH9. These genes therefore represent candidate genes for autism and specific language deficits.

Smoking in Maywood: the unhealthy southern migrant hypothesis among African Americans.

OBJECTIVES: This paper examines the "unhealthy Southern migrant" hypothesis with regard to cigarette smoking among African Americans. METHODS: Using data collected in 1992 from a sample of 1,518 African Americans in Maywood, Illinois, as part of the International Collaborative Study of Hypertension in Blacks, logistic regression analysis was conducted to examine and compare smoking behavior and sociodemographic characteristics of Southern and Midwestern-born respondents. RESULTS: African Americans born in the South were less likely (OR = .69, CI = 95%, 0.53, 0.90) to be smokers than those born in the Midwest, after controlling for other sociodemographic variables, prior smoking status, and age of arrival to Maywood. CONCLUSIONS: The results do not support the "unhealthy Southern migrant" hypothesis, with regard to cigarette smoking, and indicate the need to identify factors that protect Southern-born African-American migrants from smoking.

No association of converting enzyme insertion/deletion polymorphism with immunoglobulin A glomerulonephritis.

It has been recently reported that in type 1 diabetes the insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme gene is associated with the presence of diabetic nephropathy. Tissue angiotensin I-converting enzyme is determined by I/D polymorphism, and it has been speculated that in diabetes differences of local angiotensin II availability determine the risk of renal disease. Since angiotensin II is thought to play an important role in the evolution of renal disease in general, we tested whether genotype distribution of the I/D polymorphism is also different in patients with immunoglobulin A-glomerulonephritis (IgA-GN). Furthermore we compared IgA-GN patients with (1) stable renal function or (2) terminal renal failure to investigate a potential role of the I/D polymorphism in the renal prognosis. We examined 122 patients with biopsy-confirmed IgA-GN who had stable renal function and 82 dialysis-dependent or transplanted patients with biopsy-confirmed IgA-GN. Furthermore, in 134 healthy individuals used as controls we analyzed the DNA for normal distribution of genotypes and allele frequencies. The polymorphic region was amplified using polymerase chain reaction with specific primers. Alleles were detected on 2% agarose gels. Genotype distributions and allele frequencies were not significantly different between controls and patients with IgA-GN and stable renal function. Furthermore, no significant difference in genotype distribution was detected between patients with IgA-GN and stable renal function compared with patients with IgA-GN and end-stage renal failure, although a trend for a higher frequency of DD-homozygotes was noted in the latter group (P = 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)

Infiltration of the kidney by alpha beta and gamma delta T cells: effect on progression in IgA nephropathy.

We have studied renal biopsies from three groups of patients to determine if alpha beta T cells or gamma delta T cells are present, and whether their presence is correlated with disease progression in IgA nephropathy (IgAN). Group one comprised thin basement membrane disease biopsies (non-immunological control, N = 7); group two were patients with IgAN and stable renal function one year following biopsy (stable, N = 7); and group three were IgAN patients with rapidly declining renal function after one year (progressive, N = 7). Immunohistochemical staining using monoclonal antibodies (CD3, TcR beta, TcR delta) and molecular studies utilizing polymerase chain reaction amplification of cDNA transcribed from biopsy RNA, with primers specific for either the alpha beta TcR or gamma delta TcR, were undertaken. On immunohistochemistry a significant increase in CD3 + cells in progressive biopsies was seen (vs. control P = 0.002, vs. stable P = 0.002). The progressive biopsies infiltrate consisted of both alpha beta TcR (vs. control P = 0.001, vs. stable P = 0.003) and gamma delta TcR cells (vs. control P = 0.01). The RNA study demonstrated an increase in TcR C alpha transcription in the progressive (vs. control P = 0.003) biopsies. Increased TcR C delta transcription was seen in the progressive group (vs. control P = 0.01, vs. stable P = 0.02). We confirm that the presence of lymphocytes in IgAN biopsies predicts progressive disease. While alpha beta T cells are found in both stable and progressive disease, the presence of gamma delta T cells is only associated with progressive IgAN.

Recurrent mesangial IgA nephritis following renal transplantation.

Recurrence of mesangial IgA deposits in renal allografts of patients whose original disease was primary IgA nephropathy (IgAN) has been studied. Forty-six patients with primary IgAN received 51 renal allografts and have been followed for 3-183 months. A prospective study of 11 patients (11 biopsies) and a retrospective analysis of 17 patients (16 biopsies; 2 nephrectomy specimens) have been combined. Seventeen of the 29 allografts had recurrent mesangial IgA deposits and of these three patients have negative urinalysis, normal glomeruli by light microscopy, and stable renal function; six patients have microhaematuria, mesangial proliferative nephritis, but at present stable renal function; and five have mesangial proliferative glomerulonephritis with microhaematuria, heavy proteinuria, hypertension, and progressive allograft failure secondary to IgA disease alone, and one of these is now back on dialysis. Three other grafts with recurrent deposits are failing because of transplant glomerulopathy or rejection. The only predictor identified for recurrence of mesangial IgA deposits was length of time post-transplantation, with allograft tissue being studied at 45.9 +/- 10.0 versus 15.3 +/- 4.8 months (P = 0.008) post-transplantation in patients with and without recurrent deposits respectively. Cyclosporin A did not prevent recurrence. By virtue of a longer follow-up of patients post-transplantation than all other reported series, these results suggest that with increasing time post-transplantation recurrence of mesangial IgA disease will become increasingly important as a cause of progressive allograft dysfunction and failure unless effective treatment is found for the primary disease.

Membranous nephropathy with graft-versus-host disease in a bone marrow transplant recipient.

A 43-year-old man developed the nephrotic syndrome 26 months after allogeneic bone-marrow transplantation for chronic myeloid leukemia. This occurred during an exacerbation of graft-versus-host disease (GVHD) and both problems remitted after therapy with cyclosporine and prednisolone. Renal biopsy showed ultrastructural and immunofluorescence evidence of membranous nephropathy. Anti-nuclear antibodies (but not antiglomerular or anti-renal tubular epithelial antibodies) were detected in his serum. Experimental GVHD in mice has been associated with immune complex glomerulonephritis and the presence of IgG autoantibodies which has been attributed to abnormal T (donor)/B (recipient) cell co-operation. This association can be extrapolated to the human GVHD where autoantibody formation is better described than immune complex glomerulonephritis.

IgA antibodies to dietary antigens and lectin-binding IgA in sera from Italian, Australian, and Japanese IgA nephropathy patients.

We studied serum IgA as antibodies to dietary antigens (Ag), as lectin-binding molecules, and as conglutinin-binding immune complexes (IgAIC) in people from geographical areas in which IgA nephropathy (IgAGN) is particularly frequent. Sera from 63 Italian, 21 Australian, and 25 Japanese patients affected by IgAGN and 24 Italian, 20 Australian, and 40 Japanese healthy controls were studied. Increased values of IgAIC were detected in 42.8% of Italian patients, while only in 23.8% and 8% of Australian and Japanese patients, respectively. Mean values were significantly increased only in Italian patients (P less than 0.0001). Positive values of IgA antibodies against dietary Ag had variable prevalences, but again Italian patients showed the highest frequency, from 19% to 28.5% versus 0 to 38% in Australians and 0 to 16% in Japanese. Mean values of these antibodies were not significantly increased in any patient groups in comparison to the corresponding healthy populations. However, patients with elevated values of IgAIC had significantly higher serum concentrations of antibodies to alimentary components and a linear correlation was found between IgAIC and some IgA antibodies to food components. The relationship between these two series of data was particularly evident for Italian and Australian IgAGN patients. Moreover, the patients with positive data tended to have a cluster of increased levels of IgA antibodies against several alimentary Ag at the same time. A linear correlation was evident between values of IgA antibodies to gluten fractions and to heterologous albumins. None of these correlations was evident among healthy controls.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of IgA immune complexes on the proliferation of cultured human mesangial cells.

To investigate the role of IgA-containing circulating immune complexes (IgA-CIC) in mesangial cell proliferation, human mesangial cells were cultured with sera or IgA isolates from IgA-CIC-positive IgA nephropathy patients and negative controls. A solid phase anti-C3d enzyme-linked immunosorbent assay (ELISA) was used for the detection of IgA-CIC. Sera stimulated the proliferation of the mesangial cells at both 24 and 72 hours' incubation. However, there was no difference in the proliferation of cells incubated with sera from IgA-CIC-positive patients and negative controls. IgA-CIC-positive and negative IgA isolates both stimulated proliferation of mesangial cells at 24 hours' incubation. Our data do not support the hypothesis that IgA-CIC are directly responsible for mesangial cell proliferation.

Thin membrane nephropathy: a clinico-pathological study.

Thin membrane nephropathy is common, representing approximately 11% of non-transplant renal biopsies. A family history of renal disease is present in at least 40% of patients. Electron microscopy is essential for its diagnosis. There are no immunofluorescence markers but light microscopic changes, usually mild, are invariably present and predict the ultrastructural findings although there is no correlation with their degree. The extent of the morphological changes bears no obvious relationship either to clinical or familial features. Immunogold studies indicate that there is reduction or loss of the subepithelial portion of the basement membrane, which apparently contains normal amounts of type IV collagen. Unnecessary urological investigations may be avoided by awareness of the condition and microscopic examination of urine for dysmorphic red blood cells. Prospective long-term studies are necessary to determine the nature and consequences of the condition.

Quantitation of glomerular angiotensin II receptors in IgA nephropathy.

Mesangial cells have receptors for angiotensin II (AII) and contract in its presence. All is known also to increase the uptake of macromolecules by the mesangium. As a first step towards the investigation of a possible role for local disturbances of the renin-angiotensin system (RAS) in immune mediated mesangial proliferative glomerulonephritis, glomerular All receptors have been quantitated retrospectively in biopsy tissue from 20 patients with IgA nephropathy for comparison with 16 biopsies that showed only minor abnormalities by light microscopy and negative immunofluorescence. An autoradiographic technique using 125I labelled [Sar1, Ile8] All facilitated the quantitation of All receptors in frozen tissue sections. Following exposure to the treated sections, x-ray film was analyzed by computerized micro-densitometry. The data obtained were optical densities of areas corresponding to the presence of glomeruli verified by reference to adjacent sections stained with periodic acid-Schiff (PAS). There was no significant difference between patients 0.67 +/- 0.16 (mean +/- SD) and controls 0.61 +/- 0.15. Among patients there was no statistically significant correlation of glomerular All receptor density with either the degree of mesangial proliferation or the extent of hyperplasia of the juxtaglomerular apparatus (JGA). There was no apparent relationship with hypertension. The absence of an increase in glomerular All receptors despite proliferation of the glomerular mesangium may represent a local down regulation in patients with IgA nephropathy.

The effect of treatment with prednisolone or cyclophosphamide-warfarin-dipyridamole combination on the outcome of patients with membranous nephropathy.

Between 1973 and 1986, 109 patients with membranous nephropathy have been evaluated with respect to clinical presentation, pathological features and factors determining prognosis. Secondary disease was present in 21, and a further 21 were lost or followed for less than 12 months. The remaining 67 with idiopathic membranous nephropathy were allotted to one of three groups. Group 0 (26 patients) received no active treatment, Group 1 (12 patients) a combination of cyclophosphamide, dipyridamole and warfarin, and Group 2 (21 patients) high dose alternate day prednisolone therapy. Eight patients received other treatment or presented with end stage renal disease. No significant difference in outcome could be detected between the groups. Remission rates were equivalent as were numbers of patients judged as having progressive disease. There was no statistical difference with respect to duration of nephrotic syndrome, plasma creatinine at the end of study and change in plasma creatinine. No demonstrable benefit was obtained in predicting the outcome of disease or response to treatment from conventional pathological grading of stages I to IV as approximately equal numbers of each stage fell into good and bad categories of outcome. Similarly unusual histological features such as mesangial proliferation and immunofluorescence for deposits other than IgG and C3 were not helpful. A different approach to treatment of idiopathic membranous nephropathy is strongly recommended.

Therapeutic options in IgA nephropathy.

IgA nephropathy (IgAN) is a common form of glomerulonephritis that leads to end-stage renal disease at variable rates in 20% to 30% of cases. A rational approach to therapy requires an understanding of pathogenetic mechanisms that are largely unknown. Several therapeutic approaches have been used, generally in uncontrolled trials, aimed at lowering levels of circulating immune complexes, affecting cellular immunity, or removing antigens through dietary restriction. Thus far, no clear-cut beneficial effects are evident. Alternative means of changing glomerular hemodynamics through prevention of harmful mediators await exploration.