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G Geis

Publications and source records attributed to G Geis.

At least 19 recordsLinked to original sources
PubMed1994

Effects of Helicobacter pylori on histamine and carbachol stimulated acid secretion by human parietal cells.

Helicobacter pylori (H pylori) infection is associated with hypo, normal, and hypersecretory disorders of the gastric mucosa. Pathophysiological pathways by which H pylori interacts with acid secretion are still unclear. The effects of H pylori on (14C) aminopyrine uptake by human parietal cells were examined as an indirect assay for acid secretion. Isolated oxyntic glands were stimulated with submaximal concentrations of histamine or carbachol and incubated with sonicates of different H pylori strains. Omeprazole and sonicates of Campylobacter jejuni served as positive and negative controls, respectively. Two of four H pylori strains reduced hydrochloric acid sequestration within the parietal cells significantly and in a dose dependent manner in up to 80%. Interaction with acid secretion may therefore constitute a factor contributing to a distinct pathogenicity of H pylori strains.

Aminopyrine↗
PubMed1994

Effect of Helicobacter pylori on dbc-AMP stimulated acid secretion by human parietal cells.

This study examines the effect of different H.p. strains (A-D) on dbc-AMP stimulated acid secretion by human parietal cells in vitro. H.p. strains A and D reduced acid secretion dose-dependently between 20 and 80%. In contrast, H.p. strains B and C had little or no effect. We conclude that H.p. strains vary in their ability to suppress acid secretion, and that the site of inhibition lies beyond the c-AMP level, possibly involving the K+H(+)-ATPase of the parietal cell. Interference with acid secretion may facilitate H.p. colonization of the stomach and may prove to be an important pathogenetic factor.

Aminopyrine↗
PubMed1993

Ultrastructure and biochemical studies of the flagellar sheath of Helicobacter pylori.

Helicobacter pylori flagellar sheaths were isolated by sucrose density-gradient centrifugation and analysed by electronmicroscopy, SDS-PAGE and gas-liquid chromatography. Electronmicroscopy of thin sections of flagella showed an internal electron-dense filament and a surrounding flagellar sheath with the typical bilayer structure of a membrane. The flagellar filaments could be disintegrated by acid treatment and the resulting isolated flagellar sheaths formed vesicles, sometimes with characteristic structures. Centrifugation of flagellar preparations after acid treatment resulted in the enrichment of flagellar sheaths in the pellet. SDS-PAGE analysis of the pellet showed a reduction of the flagellin band and a number of protein bands of 150, 76, 67, 65, 53, 51, 49, 29.5, 18, 17 and 16 kDa. However, there were no major protein bands characteristic for the sheath. Differences between the protein profiles of Sarkosyl-insoluble membranes and flagellar sheaths appeared in the lower M(r) range of 30-14 kDa. Major fatty acids of isolated flagellar sheaths were C 14:0, C 19:0 cyc, C 18:0, and the LPS-specific fatty acids 3-OH C 16:0 and 3-OH C 18:0. The results demonstrate that the flagellar sheaths of H. pylori are membranes and contain LPS and proteins.

Centrifugation, Density Gradient↗
PubMed1992

Cloning and genetic characterization of a Helicobacter pylori flagellin gene.

Helicobacter pylori produces polar sheathed flagella, which are believed to be essential for the bacterial colonization of the human gastric mucosa. Here we report on the cloning and genetic characterization of a H. pylori gene encoding the subunit of the flagellar filament, the flagellin. Screening of a genomic library of H. pylori with an oligonucleotide probe derived from the N-terminal amino acid sequence of purified flagellin resulted in a recombinant plasmid clone carrying the flagellin-encoding gene flaA on a 9.3 kb Bg/II fragment. The nucleotide sequence of flaA revealed an open reading frame of 1530 nucleotides, encoding a protein with a predicted molecular mass of 53.2 kDa, which is similar in size with the purified flagellin protein in SDS-polyacrylamide gel electrophoresis. Sequence alignment of H. pylori flagellin (FlaA) with other bacterial flagellins demonstrates a high degree of similarity in the amino-terminal and carboxy-terminal regions, including those of the closely related genus Campylobacter (56% overall identity with Campylobacter coli flaA), but little homology in the central domain. Southern hybridizations of chromosomal DNA with flaA-specific probes did not reveal the presence of additional homologous flagellin genes in H. pylori. Sequence analysis of the flaA flanking regions and mapping of the flaA mRNA start site by a primer extension experiment indicated that transcription of the gene is under the control of a sigma 28-specific promoter sequence in H. pylori. The region upstream of the flaA promoter is subject to local DNA modification, resulting in the masking of two out of three closely linked HindIII restriction sites in the chromosome of strain 898-1. Escherichia coli strains harbouring the recombinant plasmid did not produce full-length flagellin and data obtained with FlaA fusion proteins using an E. coli plasmid expression system suggest that a distinct nucleotide sequence in the gene interferes with productive translation of this protein in E. coli.

Amino Acid Sequence↗
PubMed1992

Biochemical studies of Helicobacter mustelae fatty acid composition and flagella.

The fatty acid compositions of Helicobacter mustelae whole cells, isolated phospholipids, and isolated lipopolysaccharides were analyzed by gas-liquid chromatography. Major phospholipid fatty acids were C16:0, C18:0, C18:1, and C19:0 cyc. In isolated lipopolysaccharides, 3-OH-C16:0, 3-OH-C14:0, C14:0, C16:0, and C18:0 were found. The lipid composition of H. mustelae thus showed pronounced differences from that of H. pylori. Flagella were purified by mechanical shearing and centrifugation steps. In all H. mustelae strains, the flagellin had an apparent molecular mass of 53 kDa and was thus the same size as H. pylori flagellin. The flagellin of strain NCTC 12032 was further purified and subjected to N-terminal amino acid sequence analysis. The first 10 amino acids were identical to those of H. pylori flagellin, but the next 5 were different. Significant homology was also found with flagellins of other bacteria.

Amino Acid Sequence↗
PubMed1991

Fraud by physicians against Medicaid.

The inauguration of the Medicaid program in the mid 1960s ultimately led to the appearance of a wide range of new forms of illegal behavior by physicians. The fact that government authorities, instead of individual patients, were responsible for payments undoubtedly encouraged the large number of violations. A review of the background of sanctioned physicians shows an overrepresentation of psychiatrists and foreign medical graduates as well as minority-group physicians. Interviews with physicians sanctioned for Medicaid fraud and abuse indicated that they routinely placed the blame for their violations on the program, their employees, patients, or others. In particular, they find program guidelines confusing and irrational and insist that they intrude on what ought to be independent medical judgments. The enforcers, for their part, maintain that the convicted physicians are merely rationalizing self-serving and greedy behavior.

Attitude of Health Personnel↗
PubMed1991

The Amelia Stern syndrome: a diagnosis of a condition among female physicians?

Numerous studies have provided numerical portraits of some of the difficulties of women physicians at work in a field that traditionally has been the preserve of men. These studies, like much of recent feminist literature, often focus on the tension between maintaining a career and being a wife and mother. They usually provide aggregate data but fail to convey compellingly the nuances and emotions involved in the issues they address. Perri Klass's recent novel, Other Women's Children, the center point of this article, provides a case study of the thoughts and feelings attached to the issues addressed by the scientific inquiries. The book deals with the experiences of a woman pediatrician in a Boston hospital, a woman who uncertainly juggles her career and family responsibilities.

Adaptation, Psychological↗
PubMed1990

Unusual fatty acid substitution in lipids and lipopolysaccharides of Helicobacter pylori.

Cellular fatty acids, phospholipid fatty acids, and lipopolysaccharide fatty acids of four strains of Helicobacter pylori were analyzed by gas-liquid chromatography. The presence of myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, 19-carbon cyclopropane fatty acid, beta-hydroxypalmitic acid, and beta-hydroxystearic acid was confirmed. In phospholipids, myristic acid and 19-carbon cyclopropane fatty acid were the major fatty acids. Hydroxy fatty acids and unsaturated fatty acids were not detected or occurred only in small amounts. The major fatty acids of lipopolysaccharides were stearic acid, beta-hydroxypalmitic acid, and beta-hydroxystearic acid. Unsaturated fatty acids and 19-carbon cyclopropane fatty acid were not found. The unusual compositions of H. pylori phospholipid and lipopolysaccharide fatty acids may have important implications for the taxonomy, physicochemical membrane properties, and biological activity of lipopolysaccharides.

Campylobacter↗
PubMed1989

Ultrastructure and chemical analysis of Campylobacter pylori flagella.

Flagella of Campylobacter pylori were analyzed by electron microscopy and purified, and the molecular weight of the flagellin was determined. Isolation of flagella was performed by mechanical shearing from the cell surface, sucrose density gradient centrifugation, and Sepharose CL-4B gel chromatography. The flagella of C. pylori differ from those of other Campylobacter species and of most other bacteria by the presence of a flagellar sheath. The sheath narrows at the end and is linked to a club-shaped terminal structure. The molecular weight of C. pylori flagellin was 51,000.

Campylobacter↗
PubMed1989

[Serodiagnosis of Campylobacter pylori].

The colonization of gastric mucosa with Campylobacter pylori can be detected by serological methods. ELISA and immunoblot methods are currently being employed for detection of antibodies against Campylobacter pylori. In general, both tests will differentiate between Campylobacter pylori positive and Campylobacter pylori negative patients. However, 5-10% of persons with negative cultures for Campylobacter pylori have positive serological tests, but only very few patients with Campylobacter pylori associated with chronic gastritis have negative serological tests. This is true for tests detecting IgG and IgA antibodies. Tests for IgM antibodies have not been found to be useful. Immunoblot analyses have shown that detection of antibodies against a 100-120 KD antigen has a high specificity for Campylobacter pylori infection. In a small study we evaluated the possible use of serological testing for follow-up studies on patients after Campylobacter pylori therapy. We found that patients who became Campylobacter pylori negative after therapy showed a significant decline of serum IgG titers against Campylobacter pylori.

Antibodies, Bacterial↗
PubMed1985

Medical students' attitudes on physician fraud and abuse in the Medicare and Medicaid programs.

The authors in this paper report the findings of a survey of medical students at the University of California, Irvine, California College of Medicine regarding their views on the Medicare and Medicaid programs and on the problem of fraud and abuse in these government medical benefit programs. The students were asked their views on four issues: (a) the quality of various aspects of Medicare and Medicaid; (b) the seriousness and prevalence of physician fraud and abuse in the programs; (c) the punishment that should be given to violators; and (d) the causes and prevention of fraud and abuse in Medicare and Medicaid. They viewed fraud and abuse as serious but not as being widespread. They believed that physicians who violate program regulations are not likely to be punished by official agencies. They favored moderate penalties for violations. Explanations offered by the students for fraud and abuse focused on physicians' attitudes and motivations as well as on the structure of the Medicare and Medicaid programs.

Attitude of Health Personnel↗
PubMed1985

Fraud and abuse of government medical benefit programs by psychiatrists.

Government rosters of physicians suspended from the Medicare and Medicaid programs because of fraud and abuse indicate that psychiatrists form a disproportionately large segment of the total. Of the factors contributing to this situation, the most notable is that because psychiatrists charge for time rather than for services, they are more readily apprehended if they violate the rules. The authors speculate on whether in fact psychiatrists break the law more than physicians in other-specialties or whether the statistics are purely artifactual.

Crime↗
PubMed1977

Tuberculosis transmission in a large urban jail.

Following diagnosis of moderately advanced tuberculosis in an inmate of Cook County Jail, tuberculin testing was performed to assess the degree of transmission of tuberculosis within the jail. Twenty-three percent of inmates exposed to the index patient were initially found to be tuberculin positive. Subsequent tuberculin testing three months later demonstrated a 71% rate of skin-test conversion in previously tuberculin-negative inmates exposed to the index patient. The rate of infectivity of tuberculosis within a jail is analogous to a household situation. Despite major obstacles, modern programs of tuberculosis screening and treatment are essential in correctional institutions.

Adult↗
PubMed1976

Reported consequences of decriminalization of consensual adult homosexuality in seven American states.

This article reports results of a survey of police officials, prosecuting attorneys, and members of homosexual groups in the seven states that had decriminalized private homosexual behavior between consenting adults. Despite the dire predictions of many, the responses indicate that, among other things, decriminalization has had no effect on the involvement of homosexuals with minors, the use of force by homosexuals, or the amount of private homosexual behavior. Additionally, decriminalization reportedly eased somewhat the problems of the homosexual community and allowed the police to devote more time to the investigation of what generally are regarded as more serious criminal offenses.

Adult↗