Intercellular junctions in the follicular envelope of the teleost, Brachydanio rerio

The nature and distribution of intercellular junctions in the outer ovarian epithelium (serosa, mesothelium), endothelium, and follicle cells of the teleost oocyte-follicle complex were investigated by freeze-fracture electron microscopy. Tight-junctions were common between outer squamous epithelial cells, sometimes closely associated with intercalated foci of communicating junctions. The tight junctions consisted of one to several sealing strands which possessed focal discontinuities. In addition, the strands existed as loops or as short, free-ending elements; a condition that could indicate lability in their assembly or disassembly. The presence of free-ending strands could also mean that the structure serves for attachment as well as involved in the formation of occluding zonules. The free ends of some bars comprising the tight junctional strands are enlarged slightly. In outer ovarian epithelial or serosal cells, as is the case for mammalian mesothelium described by others, clusters of particles comprising communicating (gap) junctions are often intercalated within or are located in close proximity to tight junctional strands. In freeze-cleaved replicas, the outer squamous epithelial (serosal) cells contained a multitude of micropinocytotic pits (caveolae) and vesicles. Capillary endothelium also contains tight junctional components which are often closely associated with communicating junctions. Tight junctions also exist between follicle cells, but their structure changes during oocyte growth. Communicating junctions between follicle cells tend to be focal in distribution and not closely associated with tight junctions.     

Targeted inhibition of immunodeficiency virus replication in lymphocytes through retroviral mediated gene transfer

Summary To test the feasibility of gene therapy for AIDS patients, an animal model is needed to evaluate the efficacy and safety of this approach. Antiviral genes (encoding antisense RNA or viral protein) derived from Simian immunodeficiency virus (SIV) were efficiently targeted into CD4+ lymphocytes through retroviral-mediated gene transfer. After challenging with infectious viruses, the transduced lymphocytes that received antiviral genes were not only protected from SIV infection, but also from infection with HIV, for at least 25 days. Furthermore, little or no cytolytic effect (syncytium formation) was observed in the protected cells. These data demonstrated that SIV or HIV replication could be effectively blocked by antisense sequence(s) or negative dominant factors which were introduced into targeted cells through retroviral-mediated gene transfer.     

Molecular epidemiological and clinical aspects of hepatitis D virus in a unique triple hepatitis viruses (B,C, D) endemic community in Taiwan

The molecular epidemiological and clinical aspects of hepatitis D virus (HDV) in a unique HBV, HCV, and HDV triple virus endemic community in southern Taiwan were investigated. A total of 2,909 residents aged 45 or older were screened for hepatitis B surface antigen (HBsAg), anti-HCV antibody, and anti-HDV antibody (specifically for HBsAg-positive carriers). Factors that might be associated with HDV infection, viral nucleic acid detection, and genotyping of HBV, HCV, and HDV were investigated. The prevalence of HBsAg and anti-HCV were 12.6% (366/2,909) and 41.6% (1,227/2,909), respectively. For HBsAg carriers, 15.3% (56/366) were positive for anti-HDV assay. Living in a higher endemic district of HCV infection (odds ratio [OR] = 3.2; 95% confidence interval [CI] = 1.7-6.3), male gender (OR = 1.9; 95% CI = 1.1-3.6) and co-infection with HCV (OR = 1.8; 95% CI = 1.0-3.3) were significantly independent factors associated with HDV infection. The detection rate of HDV RNA among anti-HDV-positive patients was only 12.7% (7/55). The mean HBV titer of triple infection group was significantly lower than in the HBV/HDV co-infection group (2.23 vs 3.05 in log(10), copies/ml, P = 0.046). HCV RNA detection among the triple infection group showed 47.4% (9/19) viremia rate and viral loads of 579,121 IU/ml in median (16,803-1,551,190 IU/ml). The prevalent genotype of HBV was type B (23/25); HCV was 1b (7/9) and HDV was IIa/IIb (4/4). Only the presence of HCV RNA predicted the presence of elevated ALT significantly (OR = 25.0; 95% CI = 3.39-184.6). In conclusion, the geographical aggregation of HDV infection paralleled that of HCV infection in this community. HCV suppressed the replication of HBV among triple vital infection patients. HBV and HDV lapsed into a remission or nonreplicative phase in most cases, and HCV acted as a dominant factor in triple viral-infected individuals. Only the presence of HCV RNA was associated with elevated ALT values, but not HBV or HDV.     

Absence of interferons-alpha and -gamma in renal lesions of systemic lupus erythematosus and membranous glomerulonephritis

Frozen kidney biopsy sections from nine patients with systemic lupus erythematosus (SLE) as well as many other renal diseases, including IgA nephropathy, membranous nephritis, and minimal change nephrotic syndrome, were negative for interferons -alpha and -gamma by immunofluorescence. Lupus patients studied included several subjects with marked serum elevations of interferon activity as well as others with low or negative serum interferon levels. Isolated glomerular eluates prepared from normal and SLE kidneys showed no functional interferon activity by virus plaque inhibition assay. Components of normal as well as SLE serum showed no direct binding to interferon -alpha or -gamma by ELISA assays.     

Clonidine suppression and its adrenoreceptor mediation in schedule-induced polydipsia

Rats were trained in a fixed-interval, one-minute (FI 1 min) food reinforcement schedule for 1 hour daily at reduced body weight until their lever presses, licks and water intake all became stabilized for 6 days. Two experiments were performed to examine the function of sympathetic activity in schedule-induced polydipsia. In experiment 1, intracerebroventricular injection of clonidine (0.75-37.5 nmol) produced a dose-related suppression of schedule-induced drinking and licking and schedule-dependent lever pressing; these effects were later attenuated by yohimbine (5 nmol) pretreatment. Prazosin (10 nmol) also decreased clonidine-induced suppression of lever pressing, whereas neither prazosin (10 nmol) nor naloxone (10 nmol) caused any alteration in the suppression effects of clonidine on drinking and licking. None of these antagonists alone changed an individual rat's preestablished behavioral baselines. In experiment 2, the endogenous catecholamine levels, were determined in frontal cortex, hypothalamus, brainstem, dorsal obex area and adrenal glands. During the SIP situation, both the epinephrine level in adrenal glands and the norepinephrine level in hypothalamus were elevated.     

Biochemical characterization of human Thy-1

The human Thy-1 homologue (p25) was characterized biochemically for amino acid composition, sequence and carbohydrate content. Two other forms of the human Thy-1 molecule were detected and partially characterized. A 40,000 mol.wt. molecule (p40) is the dimer of p25 and its formation is increased by the presence of sodium dodecyl sulphate (SDS). The second form of 16,000 mol.wt. (p16) appears to be a cryptic or breakdown form of p25. Comparison of the amino acid compositions of p25, p40 and p16 isolated from MOLT-3 cells, with that deduced from the nucleotide sequence of the gene coding for part of the putative T cell antigen receptor, also from MOLT-3 cells, shows that the Thy-1 homologue is distinct from, but evolutionary related to, one of the putative T cell antigen receptor polypeptide chains.     

Topography and behavior of Sertoli cells in sparse culture during the transitional remodeling phase

We report observations on the behavior of Sertoli cells in sparse culture during the period from the time of plating to the time of initial confluence (the transitional remodeling phase). Changes in shape, structure, and polarity of cells, as well as changes in migration patterns and cell-cell association patterns, have been followed during the transitional remodeling phase with the aid of topographical markers. These markers are based upon differences between ultrastructural features of the basolateral and apicolateral surfaces. The basolateral surface is characterized by plasmalemmal blebs, whereas the apicolateral surface is characterized by filopodial extensions. Structural differences observed in situ remain evident in Sertoli cells isolated by sequential enzymatic treatments that are described. Another marker is provided by laminin-binding sites, which are detected exclusively on the blebbed, basolateral surfaces of freshly prepared Sertoli cell aggregates. The orientation described is sustained during the initial radial migration of Sertoli cells explanted on uncoated glass coverslips. Under these conditions, blebs are detected only on the dorsal surfaces, and filopodial extensions are evident only on the ventral surfaces. In contrast, Sertoli cells sparsely plated on a reconstituted basement membrane (air-dried Matrigel) migrate rapidly, display an extraordinary capacity to form elaborate cytoplasmic extensions for cell-cell and cell-substratum contacts, and readily retract blebs and filopodial extensions. These cells do not form mosaic borders, whereas cells plated on uncoated glass do form a monolayer with mosaic-like borders. Cells sparsely seeded on gelated Matrigel migrate preferentially at gaps between adjacent cell explants, and develop a compact cell-cell association pattern. These cells display few, if any, cytoplasmic extensions. We compare the behavior of Sertoli cells sparsely plated on Matrigel with the behavior of Sertoli cells in situ during different stages of development.     

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.