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Biomedical subjects

C Meier

Publications and source records attributed to C Meier.

At least 109 records · Page 6Linked to original sources
PubMed1996

Ability of Escherichia coli isolates that cause meningitis in newborns to invade epithelial and endothelial cells.

Escherichia coli isolates that cause meningitis in newborns are able to invade the circulation and subsequently cross the blood-brain barrier. One mechanism for traversing the blood-brain barrier might involve transcytosis through the endothelial cells. The ability of the meningitis isolate E. coli IHE3034, of serotype 018:K1:H7, to invade epithelial (T24) and endothelial (EA-hy926) cells was investigated by the standard gentamicin survival assay and by electron microscopy. Human bladder epithelial and endothelial cells were efficiently invaded by strain IHE3034, whereas epithelial human colon Caco-2 cells, canine kidney MDCK cells, and the opossum [correction of opposum] epithelial kidney cell line OK were not invaded. The ability to invade human epithelial cells of the bladder could also be demonstrated for several other newborn meningitis E. coli strains and one septicemic E. coli strain. Studies utilizing inhibitors which act on eukaryotic cells revealed a dependence on microfilaments as well as on microtubules in the process of E. coli IHE3034 entry into T24 and EA-hy926 cells. These results indicated that cell cytoskeletal rearrangements are involved in bacterial uptake and suggest that there are either two pathways (microtubule dependent and microfilament dependent) or one complex pathway involving both microtubules and microfilaments. The intracellular IHE3034 organisms were contained in a host-membrane-confined compartment mainly as single microorganisms. Intracellular replication of 1HE3034 was not detected, nor did the number of intracellular bacteria decrease significantly during a 48-h period. The ability of E. coli O18:K1 to invade and survive within certain eukaryotic cells may be another virulence factor of meningitis-associated E. coli.

Actin Cytoskeleton↗
PubMed1995

[Rhabdomyolysis in patients treated with simvastatin and cyclosporin: role of the hepatic cytochrome P450 enzyme system activity].

We describe two patients treated with a combination of cyclosporin and simvastatin who had to be hospitalized due to rhabdomyolysis. As suggested by reduced cyclosporin clearance, both patients had impaired activity of the hepatic cytochrome P450 enzyme system, which may have contributed to the development of rhabdomyolysis. After cessation of treatment with simvastatin and intensive hydration, both patients recovered within one week. While rhabdomyolysis has been described in several patients receiving the combination lovastatin/cyclosporin, so far only one case has been reported in patients treated with simvastatin/cyclosporin. Our cases therefore suggest that this complication may be more frequent than previously suspected. In patients treated with cyclosporin, HMG-CoA reductase inhibitors should be used cautiously, and concomitant administration of drugs inhibiting the hepatic cytochrome P450 enzyme system should be avoided.

Anticholesteremic Agents↗
PubMed1995

Chronic relapsing neuropathy associated with Castleman's disease (angiofollicular lymph node hyperplasia).

We report a 17-year-old patient who presented a chronic relapsing sensorimotor demyelinating neuropathy with 6 relapses over a 7-year period, preceding by 4 years the diagnosis of a multicentric angiofollicular lymph node hyperplasia. A role for Epstein-Barr virus (EBV) as a trigger of the neuropathy may be suggested by the presence of EBV DNA in the biopsied abdominal abdominal adenopathies. This unusual reported association seems to have a better prognosis than the known chronic progressive form of neuropathy associated with Castleman's disease and the Crow-Fukase syndrome.

Adolescent↗
PubMed1994

[Drug-induced (probably allopurinol) agranulocytosis. Case report and discussion].

Agranulocytosis is a rare but sometimes extremely dangerous adverse drug reaction which can be induced by almost any drug. We report the case of a 89-year-old man with a well-documented granulocyte chart, who received allopurinol in addition to preexisting therapy with cardiovascular drugs. Three weeks later agranulocytosis was found which bone-marrow biopsy indicated was drug-induced. After cessation of all drugs, isolation and antibiotic therapy, the leukocyte count returned to normal but the patient died four weeks later from progressive renal failure. A relation between allopurinol therapy and agranulocytosis was presumed. The drugs which might have caused this adverse reaction are discussed. The incidence, signs, symptoms and treatment are summarized and proposals are made concerning the action to be taken in the event of drug-induced agranulocytosis.

Acute Kidney Injury↗
PubMed1994

A chemiluminescence assay to detect antibodies to brain surface antigens in human sera.

A chemiluminescence assay was developed based on the interaction between antibodies binding to the surface of living brain cells in culture and macrophages. Such interaction leads to production of reactive oxygen radicals which can be measured by a chemiluminescence assay. This assay was used to detect anti brain antibodies in serum samples from humans with various neurological diseases. Such antibody activity was found in a high proportion of these patients. Subsequent experiments with purified IgG fractions and corresponding F(ab')2 fragments showed that the observed reactions were highly specific. It was concluded that the chemiluminescence assay is a sensitive and useful technique to detect autoantibodies in neurological diseases.

Animals↗
PubMed1993

[The drug information service in the hospital].

A Drug Information Service (MID) delivers competent information, free from influences of industry. Users are mainly physicians and pharmacists, who are not able to solve a particular pharmacologic problem by their own means. For many years such MIDs are operated in several countries by clinical pharmacists. In Switzerland, too, there is particular interest in drug-oriented information for years. In this article a short overview on basic informations and first experiences concerning this domain are presented.

Drug Information Services↗
PubMed1993

Different modes of hypervariability in (GATA)n simple sequence repeat loci.

Only a few prominent simple sequence repeat (SSR) loci of the type (GATA)n are found in the genome of the mealmoth Ephestia kuehniella Zeller. Therefore this moth was chosen as a model organism for the genetic and molecular analysis of hypervariability of SSR loci. We characterized alleles of (GATA)n loci in different Ephestia strains by cloning and genomic restriction mapping. Some variants appeared to be mere variable number of tandem repeat (VNTR) alleles, others showed considerable changes in the sequence neighbourhood of the GATA repeats. These may be produced by major rearrangements or by transposition of the (GATA)n block together with flanking sequences into a different sequence environment.

Alleles↗
PubMed1993

[Drug interactions as a cause of drug side effects].

Adverse drug interactions are a frequent clinical problem. Mechanistically, they can be classified as pharmaceutic, pharmacokinetic and pharmacodynamic interactions. Mostly, however, several different mechanisms are involved in the pathogenesis of adverse drug interactions, which makes their predictability as well as their prevention strongly dependent on the early and adequate recognition of high-risk patients. Such high-risk situations include drug-related (e.g. galenic form, stability, enantiomers), patient-related (e.g. pharmacokinetics, age, genetic disposition) and various exogenous (e.g. polypragmasy, alcohol abuse, food) factors. Especially the recent progress in the molecular characterization of hepatic biotransformation reactions has markedly increased our understanding of many potentially toxic drug interactions. In addition, several alternative compounds with distinct potentials for interactions with other drugs are now available in various therapeutic drug classes. In the future it will be important to further increase our pathophysiologic and pharmacogenetic knowledge, in order to further improve the predictability, prevention, early recognition and therapy of adverse drug interactions.

Dose-Response Relationship, Drug↗
PubMed1992

[Lyme borreliosis: significance of the serological diagnosis of an infection with Borrelia burgdorferi in neurological diseases with inflammatory cerebrospinal fluid syndrome].

To look for a correlation between positive antibody-response against Borrelia burgdorferi (Bb) and an inflammatory CSF-syndrome, from May 1988 to May 1989 333 patients from the Neurological Department of the University of Bern underwent lumbar puncture with cell count, quantitative and qualitative protein analysis and antibody determination against Bb in serum and CSF. 6 patients with active syphilis were excluded. The results of the 333 remaining patients were analyzed using chi 2 or Fisher's exact test. The antibody determination was performed using an immunoperoxidase assay (IPA). Our results are calculated for three cut-off points: Bb-IgG 1:64, 1:128, 1:256 and/or Bb-IgM 1:16, 1:32, 1:64. We found 11.7% patients to be seropositive (Bb-IgG 1: greater than or equal to 256 and/or Bb-IgM 1: greater than or equal to 64). We demonstrated the following correlations: elevated cell count (greater than 10/mm3 cells CSF) versus elevated Bb-titer (1: greater than or equal to 256), elevated total protein of CSF (greater than 48 mg%) versus elevated Bb-titer, blood-brain-barrier dysfunction versus elevated Bb-titer. In diagnostic subgroups, the same correlations were only demonstrated for PNS disorders (n = 134), and especially PNS-disorders without compression. 8 cases showed the high risk constellation inflammatory CSF syndrome and highly positive titer (Bb-IgG 1: greater than or equal to 256). Only 2 had typical neuroborreliosis, while in 2 cases the possibility of neuroborreliosis was open. Patients with MS did not show a special risk for Bb-infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Epidemiological aspects of neurological complications of Lyme borreliosis in Switzerland. A case-control study].

To determine the individual relative risk to neurologically affected patients of infection with Borrelia burgdorferi, within the framework of a multicenter case control study encompassing the four neurological departments of the Universities of Basel, Bern, Zurich and Lausanne, 378 patients and 1134 healthy blood donors serving as controls underwent analysis for antibodies against Borrelia burgdorferi by ELISA. The seroprevalence were estimated for a cut-off point of 2 standard deviations from the mean, these values corresponding to cut-off points of 1:32 for IgM and 1:256 for IgG by immunofluorescence testing. For IgM, 4.8% of the neurological patients were positive versus 4.1% of controls; the corresponding values for IgG were 10.1% versus 10.7% respectively. Hence, neurologically affected patients were not at higher risk for infection with Borrelia burgdorferi than were controls. We found no elevated relative risk in any diagnostic subgroup. The results of a positive Lyme serology must therefore be interpreted with care and in relation to clinical and CSF findings. On the basis of our results, screening for Lyme borrelioses serves no purpose.

Adolescent↗
PubMed1992

Regression of coronary artery dimensions after successful aortic valve replacement.

BACKGROUND: The effect of regression of myocardial hypertrophy on coronary artery dimensions was evaluated in patients with aortic valve disease who underwent valve replacement. METHODS AND RESULTS: Cross-sectional area (CSA) of the three major coronary arteries (left anterior descending [LAD], left circumflex [LCx], and right coronary artery) was determined by quantitative coronary arteriography in 15 patients with aortic valve disease before and 38 months (range, 14-113 months) after successful aortic valve replacement. Twelve normal subjects served as controls. Left ventricular (LV) angiographic mass was calculated according to the method of Rackley. CSA of the left coronary artery was larger in aortic valve disease than in controls (LAD, 15 versus 8 mm2, p less than 0.001; LCx, 14 versus 6 mm2, p less than 0.001). After valve replacement, CSA of the left coronary artery decreased (LAD, 12 mm2, p less than 0.05 versus before surgery; LCx, 11 mm2, p less than 0.05 versus before surgery) but remained significantly larger than in controls. CSA of the right coronary artery in patients with aortic valve disease was not different from controls. LV muscle mass was significantly increased in aortic valve disease patients before (364 g) and after (250 g) valve replacement compared with controls (135 g). The appropriateness of coronary artery size with respect to muscle mass was evaluated by normalizing CSA of the left coronary artery (LAD + LCx) per 100 g of LV muscle mass (mm2/100 g). This index amounted to 11 mm2/100 g in controls, to 8 mm2/100 g in preoperative patients (p less than 0.05 versus controls), and to 10 mm2/100 g in postoperative patients with aortic valve disease (p = NS versus controls). CONCLUSIONS: In patients with aortic valve disease, CSA of the proximal LAD and LCx is increased, but this increase is not sufficient to keep CSA per 100 g of LV mass within normal limits. The postoperative decrease in muscle mass is associated with a decrease in the size of LAD and LCx, whereas the size of the right coronary artery remains unchanged. In contrast to the preoperative state, the residually hypertrophied LV myocardium after aortic valve replacement is supplied by an enlarged but adequately sized LAD and LCx.

Aortic Valve↗