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G E Pfyffer

Publications and source records attributed to G E Pfyffer.

69 records · Page 4Linked to original sources
PubMed1993

Characteristics of CDC group 1 and group 1-like coryneform bacteria isolated from clinical specimens.

Fifteen strains of CDC group 1 coryneform and biochemically similar bacteria were isolated from clinical specimens. Of the 15 strains isolated, 11 were derived from abscesses and purulent lesions, mostly from the upper part of the body, and 3 were grown from blood cultures. Nine strains were associated with mixed anaerobic but no other aerobic flora. Seven strains exhibited the classical biochemical profile of CDC coryneform group 1; however, eight strains were unable to reduce nitrate and were called "group 1-like." Other reactions to differentiate CDC group 1 and group 1-like coryneform rods include alpha-hemolysis on human blood agar, fermentation of adonitol, and the presence of alkaline phosphatase. Fifteen strains showed marked CAMP reactions on different erythrocyte agars. Gas-liquid chromatography of volatile and nonvolatile fatty acids as well as cellular fatty acid patterns and the composition of cell wall components suggest that CDC group 1 and group 1-like coryneform bacteria do not belong to the genus Corynebacterium but possibly to the genus Actinomyces or Arcanobacterium. DNA-DNA hybridization studies revealed that group 1 and group 1-like strains represent different species.

Actinomycetales↗
PubMed1993

Characterization of Brevibacterium spp. from clinical specimens.

Nonfermenting coryneform bacteria identified as Brevibacterium spp. were isolated from routine clinical specimens. Four strains were derived from peritoneal fluid and has presumably been involved in the pathogenesis of continuous ambulatory peritoneal dialysis peritonitis. Another five isolates most probably represented skin contaminants. Cell wall and lipid analyses confirmed the genus identification. Strains in this taxon are difficult to distinguish from other biochemically inactive and nonmotile coryneform species but show characteristics cellular fatty acid profiles. In vitro susceptibilities to commonly used antibiotics were determined.

Ascitic Fluid↗
PubMed1989

Accumulation of acyclic polyols and trehalose as related to growth form and carbohydrate source in the dimorphic fungi Mucor rouxii and Candida albicans.

Yeast (Y) and hyphal (H) cells of Mucor rouxii and Candida albicans were cultivated in liquid media containing different carbon nutrient sources (glucose, fructose, ribose) and their free acyclic polyol and trehalose contents determined using capillary gas liquid chromatography (TMS- and OAc-derivatization). Irrespective of growth form and C-source, the fraction of the water-soluble neutral components of the cellular mass of the cultures - highly homogeneous with regard to the respective cell form produced - contained glycerol, ribitol and arabitol, in addition to trehalose. The polyols contributed 0.5-2% to the biomass of M. rouxii and 1.5-6% to that of C. albicans; the values for trehalose ranged from 0.2-11% in the former and 1-3.5% in the latter species. Mucor contained higher amounts of ribitol and arabitol in H cells and larger quantities of trehalose and glycerol in Y cells. In Candida, too, hyphae always exhibited higher ribitol contents, whereas arabitol attained higher levels in yeasts under almost any conditions - regardless of the type of medium (synthetic vs. complex), stage of culture (early vs. late log-phase) and strain used. Glycerol concentration was not correlated with the growth form; trehalose contents tended to be higher in Y cells. Taking into account the facts that C. albicans and certain Mucor species are agents of opportunistic infections and are invasive mainly in the filamentous form, and that the prospective hosts do not accumulate either of these carbohydrates, the possibility is considered of using trehalose- and polyol-metabolizing enzymes as targets for designing antifungal drugs.

Candida albicans↗
PubMed1987

Calcium-binding proteins in carcinoma, neuroblastoma and glioma cell lines.

Antisera against the Ca2+-binding proteins parvalbumin, calbindin D-28K, and the S-100 proteins were used to study the distribution of their target proteins in selected human carcinoma (LICR-HN6;Caco-2), mouse neuroblastoma (clone NB-2a), and rat glioma cell lines (clone C-6). Pronounced staining with anti-parvalbumin was observed in the cytosol of all cells as well as in some nuclei, in particular, mitotic nuclei were highly immuno-reactive. Applying light and immune-electron microscopy (colloidal gold labelling) the parvalbumin-fluorescence was associated with filaments in the LICR-HN6 cells. However, this immunoreactivity was not a result of the presence of parvalbumin itself--as shown by biochemical analyses (HPLC, 2D-PAGE)--but was due to the presence of a Ca2+-binding and tumour-associated protein with similar biochemical and immunological properties. S-100 proteins were present in all tumour cell lines but their intracellular distribution was different from calbindin D-28K. Calbindin-immunoreactivity was found on the membranes of the carcinoma cell lines whereas neuroblastoma and glioma cells remained unlabelled. It is suggested that these proteins might be involved in the modulation of the enhanced stimulation of Ca2+-dependent processes occurring in tumour cells.

Animals↗
PubMed1987

Developmental and functional studies of parvalbumin and calbindin D28K in hypothalamic neurons grown in serum-free medium.

The Ca2+-binding proteins parvalbumin (Mr = 12K) and calbindin D28K [previously designated vitamin D-dependent Ca2+-binding protein (Mr = 28K)] are neuronal markers, but their functional roles in mammalian brain are unknown. The expression of these two proteins was studied by immunocytochemical methods in serum-free cultures of hypothalamic cells from 16-day-old fetal mice. Parvalbumin is first detected in all immature neurons, but during differentiation, the number of parvalbumin-immunoreactive neurons greatly declines to a level reminiscent of that observed in vivo, where only a subpopulation of neurons stains for parvalbumin. In contrast, calbindin D28K was expressed throughout the period investigated only in a distinct subpopulation of neurons. Depolarization of fully differentiated hypothalamic neurons in culture resulted in a dramatic decrease of parvalbumin immunoreactivity but not of calbindin D28K immunoreactivity. The parvalbumin staining was restored on repolarization. Because the anti-parvalbumin serum seems to recognize only the metal-bound form of parvalbumin, the loss of immunoreactivity may signal a release of Ca2+ from intracellular parvalbumin during depolarization of the cells. We suggest that parvalbumin might be involved in Ca2+-dependent processes associated with neurotransmitter release.

Animals↗
PubMed1984

Calcium-binding proteins in human carcinoma cell lines.

Elevated levels of Ca2+-binding proteins are reported in transformed cells and thought to be involved in their uncontrolled proliferation and often increased motility. Therefore, three cell lines [LICR(Lond)-HN 1, -HN 2, and -HN 6] derived from human carcinomas displaying various degrees of locomotive activity were investigated for the presence of parvalbumin and related Ca2+-binding proteins. By applying different immunohistochemical methods in conjunction with a monospecific anti-parvalbumin antiserum, an intense staining was seen in cells displaying translocative motility. Often in these cells, an association with filamentous structures located in the nuclear region was observed. Unique Ca2+-binding proteins, absent from comparable normal tissue, were found in the malignant cell lines when analyzed by two-dimensional polyacrylamide gel electrophoresis and high-performance liquid chromatography. From these tumor cells a protein (Mr, 12,000; pI, 4.8) was isolated that crossreacted with antiparvalbumin antiserum. Peptide maps of this protein revealed a further structural homology to parvalbumin (Mr, 12,000; pI, 4.9). In analogy to muscle, where there is evidence for a regulatory role of parvalbumin in the contraction-relaxation cycle, we speculate that this protein is tumor-associated and connected to the motile behavior of carcinoma cells.

Calcium-Binding Proteins↗
PubMed1984

Parvalbumin, a neuronal protein in brain cell cultures.

Dissociated brain cell cultures were derived from 14-day-old embryonic as well as from newborn mice. The cells were grown in a medium containing 10% fetal calf serum. Indirect immunofluorescence was performed using antisera directed against the Ca2+-binding protein parvalbumin (Mr 12,000). In embryonic cultures a large proportion of cells was intensely stained by antiparvalbumin . In double-labelling experiments involving the simultaneous application of antisera against parvalbumin and the neuron-specific enolase, the enolase-containing cells were also parvalbumin-positive and both antisera revealed identical intracellular staining patterns. Conversely, almost no parvalbumin- and enolase-positive cells were present in cultures derived from newborn mice. However, in these cultures many cells were immunoreactive toward the myelin basic protein, an accepted marker for oligodendrocytes. The presence of parvalbumin within the embryonic brain cell cultures was confirmed by analyses of the culture extracts (4 mM EDTA, pH 7.5) by HPLC on reverse-phase supports, two-dimensional polyacrylamide gel electrophoresis, and immunoblotting. The present study suggests that in mouse brain cell cultures, parvalbumin is localized in neurons.

Animals↗
PubMed1982

Photochemical interaction of dictamnine, a furoquinoline alkaloid, with fungal DNA.

The furoquinoline alkaloid dictamnine has been shown to provoke lethal damage to filamentous fungi in near ultraviolet light. The phototoxicity was more pronounced against Mucor hiemalis and Mucor ramannianus than against Fusarium graminearum and Penicillium italicum. In vitro, labeled dictamnine was shown to form covalent monoadducts with purified DNA from M. hiemalis in the presence of long-wave ultraviolet light. Addition of [3H]dictamnine to cultures of the same organism showed photobinding with the fungal DNA in vivo. These results support the suggestion made earlier, on the basis of in vitro experiments with calf thymus DNA, that DNA represents a major cellular target in vivo for the phototoxicity of the alkaloid.

Alkaloids↗
PubMedDate not supplied

Brevibacterium species as a cause of osteomyelitis in a neonate.

A case of osteomyelitis of the sternum due to Brevibacterium sp. in a neonate following mastitis of the mammary gland 20 days previously is described. The disease was successfully treated with cefazolin and oxacillin. The results of microbiological examinations and their significance are discussed.

Brevibacterium↗
PubMedDate not supplied

Molecular epidemiology of tuberculosis among HIV-infected persons in Switzerland: a countrywide 9-year cohort study. Swiss HIV Cohort Study.

We investigated tuberculosis transmission during a nine-year period (1988-1996) in a countrywide community-based cohort of HIV-infected persons in Switzerland (the Swiss HIV Cohort Study [SHCS]). We estimated the proportion of tuberculosis cases due to reinfection and relapse, and assessed factors which may increase the risk of tuberculosis transmission. HIV-infected persons were followed prospectively and molecular fingerprinting with insertion sequence (IS) 6110, 36-bp direct repeat, and IS6110-PCR was used to determine M. tuberculosis case clustering. Out of 7999 SHCS participants, 267 persons developed tuberculosis. 158 M. tuberculosis isolates from 138 patients were available for study. Molecular analysis identified 33 (24%) episodes of tuberculosis associated with 12 clusters including 2 to 8 patients. Two patients experienced reinfection, and nine had a relapse. Detailed contact investigation identified definite or possible epidemiological links between 21 of 33 cluster patients (64%). Multivariate logistic regression analysis did not identify any risk marker significantly associated with clustering. During a nine-year period, one fourth of tuberculosis cases were grouped in clusters within a selection of 138 HIV-infected patients. This may represent the lowest estimation of recently acquired tuberculosis infection. There were no large institutional or community outbreaks among HIV-infected participants of the Swiss HIV Cohort Study.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Sporadic tuberculous meningoencephalitis.

Tuberculous meningoencephalitis in a 24-month-old boy is reported. He contracted the infection from his apparently healthy grandfather with unnoticed pulmonary tuberculosis, as suggested by restriction fragment length polymorphism analysis of the isolated pathogen.

Cerebrospinal Fluid↗
PubMedDate not supplied

Mycobacterium canettii, the smooth variant of M. tuberculosis, isolated from a Swiss patient exposed in Africa.

An exceptionally smooth and glossy morphotype of Mycobacterium tuberculosis complex was isolated from a 56-year-old Swiss patient with mesenteric tuberculosis. Direct 16S rRNA sequence analysis of the hypervariable signature gene regions revealed a 100% homology to the specific M. tuberculosis complex sequence. Spoligotyping and restriction fragment length polymorphism analyses using the insertion sequences IS6110 and IS1081 and the polymorphic GC-rich sequence as additional genetic markers identified the isolate as the novel taxon M. canettii. Like a Somali child with a similar case, this patient probably contracted the infection in Africa, which raises questions about the geographic distribution of M. canettii.

Genetic Variation↗
PubMedDate not supplied

Multidrug-resistant tuberculosis in prison inmates, Azerbaijan.

In a tuberculosis (TB) program in the Central Penitentiary Hospital of Azerbaijan, we analyzed 65 isolates of Mycobacterium tuberculosis by IS6110-based restriction fragment-length polymorphism (RFLP) and spoligotyping. From 11 clusters associated with 33 patients, 31 isolates had an IS6110-based banding pattern characteristic of the Beijing genotype of M. tuberculosis. In addition, 15 M. tuberculosis isolates with similar RFLP patterns constituted a single group by spoligotyping, matching the Beijing genotype. Multidrug resistance, always involving isoniazid and rifampin, was seen in 34 (52.3%) of 65 isolates, with 28 belonging to the Beijing genotype.

Adult↗