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M Theis

Publications and source records attributed to M Theis.

10 recordsLinked to original sources
PubMed2001

A new alternatively spliced transcript of the mouse connexin32 gene is expressed in embryonic stem cells, oocytes, and liver.

The rodent gap junction protein connexin32 (Cx32) is highly expressed in hepatocytes, less abundantly in Schwann cells and oligodendrocytes, and at low levels in the early mouse embryo. In both hepatocytes and Schwann cells, Cx32 expression is directed by alternative promoter regions (P1 and P2) which activate differently spliced transcript isoforms. Here we describe a third Cx32 transcript isoform expressed in embryonic cells, oocytes, and liver. Using competitive polymerase chain reaction, we have found that this new Cx32 transcript containing exon 1A is 200-fold less abundant in liver than the Cx32 isoform with exon 1. In mouse oocytes, the exon 1A-containing Cx32 transcript is exclusively expressed. Immunoblot analyses revealed no Cx32 protein expression in embryonic stem cells, whereas it has previously been demonstrated in oocytes. When the putative Cx32 promoter region upstream of exon 1A was cloned before the lacZ reporter gene, transient transfection yielded weak expression in embryonic stem cells. Our results suggest that the exon 1A-containing Cx32 isoform is likely to be inherited as an oogenetic product but not translated during early embryogenesis.

Alternative Splicing↗
PubMed2001

Microglia at brain stab wounds express connexin 43 and in vitro form functional gap junctions after treatment with interferon-gamma and tumor necrosis factor-alpha.

Gap junctional communication between microglia was investigated at rat brain stab wounds and in primary cultures of rat and mouse cells. Under resting conditions, rat microglia (FITC-isolectin-B4-reactive cells) were sparsely distributed in the neocortex, and most (95%) were not immunoreactive for Cx43, a gap junction protein subunit. At brain stab wounds, microglia progressively accumulated over several days and formed aggregates that frequently showed Cx43 immunoreactivity at interfaces between cells. In primary culture, microglia showed low levels of Cx43 determined by Western blotting, diffuse intracellular Cx43 immunoreactivity, and a low incidence of dye coupling. Treatment with the immunostimulant bacterial lipopolysaccharide (LPS) or the cytokines interferon-gamma (INF-gamma) or tumor necrosis factor-alpha (TNF-alpha) one at a time did not increase the incidence of dye coupling. However, microglia treated with INF-gamma plus LPS showed a dramatic increase in dye coupling that was prevented by coapplication of an anti-TNF-alpha antibody, suggesting the release and autocrine action of TNF-alpha. Treatment with INF-gamma plus TNF-alpha also greatly increased the incidence of dye coupling and the Cx43 levels with translocation of Cx43 to cell-cell contacts. The cytokine-induced dye coupling was reversibly inhibited by 18 alpha-glycyrrhetinic acid, a gap junction blocker. Cultured mouse microglia also expressed Cx43 and developed dye coupling upon treatment with cytokines, but microglia from homozygous Cx43-deficient mice did not develop significant dye coupling after treatment with either INF-gamma plus LPS or INF-gamma plus TNF-alpha. This report demonstrates that microglia can communicate with each other through gap junctions that are induced by inflammatory cytokines, a process that may be important in the elaboration of the inflammatory response.

Animals↗
PubMed2001

Endothelium-specific replacement of the connexin43 coding region by a lacZ reporter gene.

The murine gap junction protein connexin43 (Cx43) is expressed in blood vessels, with vastly different contribution by endothelial and smooth muscle cells. We have used the Cre recombinase under control of TIE2 transcriptional elements to inactivate a floxed Cx43 gene specifically in endothelial cells. Cre-mediated deletion led to replacement of the Cx43 coding region by a lacZ reporter gene. This allowed us to monitor the extent of deletion and to visualize the endothelial expression pattern of Cx43. We found widespread endothelial expression of the Cx43 gene during embryonic development, which became restricted largely to capillaries and small vessels in all adult organs examined. Mice lacking Cx43 in endothelium did not exhibit altered blood pressure, in contrast to mice deficient in Cx40. Our results show that lacZ activation after deletion of the target gene allows us to determine the extent of cell type-specific deletion after phenotypical investigation of the same animal.

Animals↗
PubMed2001

hGFAP-cre transgenic mice for manipulation of glial and neuronal function in vivo.

With the goal of performing astrocyte-specific modification of genes in the mouse, we have generated a transgenic line expressing Cre recombinase under the control of the human glial fibrillary acidic protein (hGFAP) promoter. Activity was monitored by crossing the hGFAP-cre transgenics with either of two reporter lines carrying a lacZ gene whose expression requires excision of loxP-flanked stop sequences. We found that lacZ expression was primarily limited to the central nervous system, but therein was widespread in neurons and ependyma. Cell types within the brain that notably failed to activate lacZ expression included Purkinje neurons of the cerebellum and choroid plexus epithelium. Onset of Cre expression began in the forebrain by e13.5, suggesting that the hGFAP promoter is active in a multi-potential neural stem cell.

Animals↗
PubMed2000

General or cell type-specific deletion and replacement of connexin-coding DNA in the mouse.

Here we describe several gene targeting approaches currently used in our laboratory for the generation of deletion or replacement mutants of connexin genes in the mouse and discuss the advantage of the double-replacement strategy for the generation of conditional mutants. For the analysis of complementary functions of connexins, it will be necessary to generate mice with mutations in several connexin genes. We also report how this can be effectively accomplished. The replacement of targeted connexin-coding DNA with a reporter gene, to mimic expression of the deleted gene product, is currently being used in several laboratories. The use of different reporter genes or their differently localized gene products could allow distinction of promoter activity in double or triple connexin mutant mice.

Animals↗
PubMed1997

Integrating Hazard Analysis and Critical Control Point (HACCP) and sanitation for verifiable food safety.

Reliable, verifiable food safety requires the application of technologically correct methods in a systematic way. This requires making a distinction between sanitation and Hazard Analysis and Critical Control Point (HACCP) and integrating these two systems into one food safety system. Although sanitation and HACCP share the same goal of producing safe food products, the focus of sanitation is on the environment surrounding the food to prevent contamination, whereas the focus of HACCP is on controlling hazards intrinsic to food materials. Together they provide the organizational base for applying the correct methods and procedures to ensure and verify that food served is safe for foodservice clients. These approaches also provide records that demonstrate that food safety measures have been planned and completed as planned. One way to demonstrate a responsible approach to food safety is to understand the differences between sanitation and HACCP and to build approaches to food safety that use both of these systems. The resulting integrated system has a better chance of controlling all the hazards than either system by itself.

Cooking↗
PubMed1991

Time spent in state-recommended functions by consultant dietitians in Wisconsin skilled nursing facilities.

In this study we determined how consultant dietitians working in Wisconsin skilled nursing facilities distributed their time among contracted duties. At the time of the study, the 400 skilled nursing facilities in Wisconsin employed 160 consultant dietitians. Of these, 135 consultant dietitians were eligible to participate in the study. A mailed questionnaire was used to collect data on educational background, experience, and actual time spent in state-recommended functions, additional resident-care functions, and additional non-resident-care functions. Completed, usable questionnaires were returned by 65 (48%) of the 135 consultant dietitians. Data were analyzed statistically and presented as medians, means, and standard deviations. Mean time (minutes) consultant dietitians spent per resident admission activity was as follows: data collection, 31.3; care planning, 28.9; resident counseling, 18.5; medical record review, 17.7; discharge referral, 15.4. Mean time (minutes) consultant dietitians spent per month in other activities was as follows: facility evaluation, 75.3; student training, 120; allied staff training, 38.7; foodservice staff training, 46.8; technician training, 128; menu planning, 76.9; diet manual review, 21.6; quality assurance programs, 31.8; quality assurance audits, 34; report preparation for facility administrator, 33.4; and policy development, 32.8. Mean times reported in this study may be used as time guidelines by the state of Wisconsin for evaluating how skilled nursing facilities contract for services of consultant dietitians. Other state and federal regulatory agencies could use the time guidelines for comparison and verification until future studies provide more data on time standards for state-recommended functions, additional resident-care functions, and additional non-resident-care functions.

Consultants↗