Refined localization of human connexin32 gene locus, GJB1, to Xq13.1

Connexins are the peptide subunits of gap junctions that interconnect cells to allow the direct, intercellular transfer of small molecules. Recently, the human connexin32 gene (locus designation GJB1) has been regionally mapped by three other laboratories to Xp11-q13, Xcen-q22, and Xp11-q22. The smallest region of overlap from these studies is Xcen-q13. By using a series of somatic cell hybrid mapping panels and a rat connexin32 cDNA probe, we have localized the human GJB1 locus to a much smaller region in proximal Xq13.1, in interval 8, as described by Lafreniere et al. (8).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30018/1/0000386.pd

Genetic manipulation of gap junctions in cultured cells.

Intercellular signalling is one system whose imbalance could trigger lost cell growth control. Among the mechanisms involved in intercellular singalling, gap junctional communication (GJC) has emerged as a possible regulator of cell growth. This dissertation used molecular genetic approaches to study the role of GJC in cell growth regulation. Two antisense systems were designed to inhibit GJC in WB\sp{\rm r} cells, a non-tumorigenic, rat liver cell line which expresses connexin43 gap junction protein and has a high endogenous GJC capacity. The first method, using an expression vector containing a connexin43 cDNA in the antisense orientation, was not useful for blocking GJC in WB\sp{\rm r} cells, with antisense expression apparently unstable. Vector sequences were lost from clones expressing connexin43 antisense RNA, and these cells grew more slowly than did control cells. These data suggested a selective disadvantage to antisense RNA expression. The second antisense system was more successful. A phosphorothioate DNA oligomer (oligo), targeted against the connexin43 gene, qualitatively decreased connexin43 protein as evidenced by decreased immunofluorescence staining of contacting cell membranes with an anti-connexin43 antibody. Oligo-treated cells assayed by dye transfer microinjection showed a slight reduction in dye transfer capacity among antisense oligo-treated cells. However, both immunofluorescence and dye transfer assays suggested that cytotoxicity was associated with the antisense oligo treatment. These data do not directly address a role for GJC in cell growth regulation, however, a possible requirement for gap junctions in cell survival is supported by these results. Because decreased GJC is associated with oncogene expression and with specific malignancies, it was of interest to map human gap junction genes and correlate their chromosomal location to the loci of proto-oncogenes. Somatic cell mapping panels were used with rat cDNA probes to map two human connexin gene loci, connexin32 (GJB1) to Xq13.1, and connexin43 (GJA1) to 6q21-23.1. Although the role of gap junctions in cell growth regulation is still ambiguous, the work contained in this dissertation extends the current genetic analysis of gap junctions in cultured cells.Ph.D.BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/103059/1/9303722.pdfDescription of 9303722.pdf : Restricted to UM users only

Cultured myometrial cells establish communicating gap junctions

Myometrial cells were isolated and cultured from term rat uterus. The myometrial origin of the cultures was verified by antibody staining of cellular desmin and [alpha]-smooth muscle actin. The presence of functional gap junctions was indicated by transfer of radiolabeled nucleotide and microinjected Lucifer yellow dye. The cultured cells expressed mRNA recognized by a connexin43 gap junction cDNA probe. To our knowledge, this is the first report that isolated myometrial cells form gap junctions in culture.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28382/1/0000151.pd

Heat, Disparities, and Health Outcomes in San Diego County's Diverse Climate Zones.

Climate variability and change are issues of growing public health importance. Numerous studies have documented risks of extreme heat on human health in different locations around the world. Strategies to prevent heat-related morbidity and reduce disparities are possible but require improved knowledge of health outcomes during hot days at a small-scale level as important within-city variability in local weather conditions, socio-demographic composition, and access to air conditioning (AC) may exist. We analyzed hospitalization data for three unique climate regions of San Diego County alongside temperature data spanning 14 years to quantify the health impact of ambient air temperature at varying exceedance threshold levels. Within San Diego, coastal residents were more sensitive to heat than inland residents. At the coast, we detected a health impact at lower temperatures compared to inland locations for multiple disease categories including heat illness, dehydration, acute renal failure, and respiratory disease. Within the milder coastal region where access to AC is not prevalent, heat-related morbidity was higher in the subset of zip codes where AC saturation is lowest. We detected a 14.6% increase (95% confidence interval [4.5%, 24.6%]) in hospitalizations during hot weather in comparison to colder days in coastal locations where AC is less common, while no significant impact was observed in areas with higher AC saturation. Disparities in AC ownership were associated with income, race/ethnicity, and homeownership. Given that heat waves are expected to increase with climate change, understanding health impacts of heat and the role of acclimation is critical for improving outcomes in the future

Alexithymia in anorexia nervosa: the mediating role of depression

The role of depression in the expression of alexithymia in anorexia nervosa (AN) has been controversially explained and several variables that may mask or increase the presence of emotional difficulties have scant examination in previous studies. This study aims to analyze the associations between alexithymia and state variables, such as age, BMI, illness duration, treatment duration, and medication status in AN participants, and to test the mediating role of depression in emotional difficulties. The Toronto Alexithymia Scale (TAS-20) and the Zung Self-Rating Depression Scale were administrated to 160 females: 80 participants with AN and 80 healthy controls. High levels of alexithymia were not a function of state variables. The mediating role of depression differed by the alexithymia dimension, with total mediation found for the TAS-DDF and partial mediation found for the TAS-DIF. Alexithymia is a relevant feature throughout the spectrum of AN and does not seem to be related to developmental maturation and some clinical features. Depression is probably the variable that best accounts for the variance in alexithymia, but is not a complete explanation for the known cognitive-affective disturbances in AN. Specific emotional competencies require scrutiny during psychiatric treatment