Search PubMed⌕ Search

Biomedical subjects

J Wagner

Publications and source records attributed to J Wagner.

At least 361 records · Page 20Linked to original sources
PubMed1986

Skinned smooth muscle: calcium-calmodulin activation independent of myosin phosphorylation.

In chemically skinned chicken gizzard smooth muscle fibers investigated shortly after preparation, a contraction may be induced by calcium and calmodulin which is independent of myosin phosphorylation at intermediate Ca2+-concentrations. However, fibers stored for a prolonged period also contract in the absence of exogenous calmodulin and exhibit a close relationship between force development and myosin phosphorylation.

Animals↗
PubMed1986

Serum bactericidal activity of two newer quinolones against Salmonella typhi compared with standard therapeutic regimens.

The bactericidal activity of two newer quinolones, ciprofloxacin and ofloxacin, against eight strains of Salmonella typhi was examined by the serum dilution test and studies of bacterial killing kinetics in human serum, and compared to standard regimens. Bactericidal titers for ciprofloxacin ranged from 1:388 to 1:119 two hours and from 1:119 to 1:57 six hours after volunteers received an oral dose of 500 mg. The respective titers obtained after a 200 mg oral dose of ofloxacin were somewhat lower, but still exceeded 1:16 in all instances. Studies of bacterial killing kinetics demonstrated a rapid bactericidal action of both drugs against all strains tested. Compared to the classical anti-typhoid agents chloramphenicol, cotrimoxazole and amoxicillin, the new quinolones showed both markedly higher bactericidal titers and more rapid killing of Salmonella typhi in human serum.

Adult↗
PubMed1986

Stress fibers in the splenic sinus endothelium in situ: molecular structure, relationship to the extracellular matrix, and contractility.

In the present study, we investigated structural and functional aspects of stress fibers in a cell type in situ, i.e., the sinus endothelium of the human spleen. In this cell type, stress fibers extend underneath the basal plasma membrane and are arranged parallel to the cellular long axis. Ultrastructurally, the stress fibers were found to be composed of thin actin-like filaments (5-8 nm) and thick myosin-like filaments (10-15 nm X 300 nm). Actin filaments displayed changes in polarity (determined by S-1-myosin subfragment decoration), which may allow a sliding filament mechanism. At their plasmalemmal attachment sites, actin filaments exhibited uniform polarity with the S-1-arrowhead complexes pointing away from the plasma membrane. Fluorescence microscopy showed that the stress fibers have a high affinity for phalloidin and antibodies to actin, myosin, tropomyosin, and alpha-actinin. Vinculin was confined to the cytoplasmic aspect of the plasmalemmal termination sites of stress fibers, while laminin, fibronectin, and collagens were located at the extracellular aspect of these stress fiber-membrane associations. Western blot analysis revealed polypeptide bands that contained actin, myosin, and alpha-actinin to be major components of isolated cells. Exposure of permeabilized cells to MgATP results in prominent changes in cellular shape caused by stress fiber contraction. It is concluded that the stress fibers in situ anchored to cell-to-extracellular matrix contacts can create tension that might allow the endothelium to resist the fluid shear forces of blood flow.

Actin Cytoskeleton↗
PubMed1986

Ciprofloxacin: a comparative evaluation of its bactericidal activity in human serum against four enterobacterial species.

Serum bactericidal titres following a 200 mg i.v. dose of ciprofloxacin were measured in healthy volunteers and compared with those achieved with standard doses of ceftazidime, piperacillin and gentamicin, given alone or in combination. Five strains of each of four enterobacterial species were included in the study. Bactericidal titres 1 h after infusion of ciprofloxacin exceeded 1:16 for Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Enterobacter cloacae. While ceftazidime produced higher peak bactericidal titres against the Enterobacteriaceae, piperacillin was less effective than ciprofloxacin against three of the four enterobacterial species tested. Among the combinations, only piperacillin/gentamicin showed synergistic activity against some strains. Studies of bacterial killing kinetics again confirmed the high bactericidal activity of ciprofloxacin for the Enterobacteriaceae. The combination of ciprofloxacin with gentamicin resulted in more rapid killing of some strains of Klebsiella pneumoniae and Proteus vulgaris.

Adult↗
PubMed1985

N-Acetyl decarboxylated S-adenosylmethionine, a new metabolite of decarboxylated S-adenosylmethionine: isolation and characterization.

Treatment with ornithine decarboxylase inhibitors leads to a marked increase of decarboxylated S-adenosylmethionine (dc-SAM) in various tissues, accompanied by the concomitant formation of a metabolite of dc-SAM. This metabolite has been isolated from rat prostate samples by a combination of chromatographic procedures. The use of IH-NMR and of fast atom bombardment mass spectometry and the synthesis of an authentic sample allowed the unambiguous characterization of this unknown compound as the N-acetyl derivative of dc-SAM. A reverse-phase high performance liquid chromatography procedure was developed for the separation of dc-SAM and its N-acetyl derivative into their diastereomers resulting from the chiral sulfonium group.

Acetylation↗
PubMed1985

[Bacterial colonization of the rat jejunum in long-term nutrition with an elemental diet].

Elemental diets and peptide diets are increasingly used in the treatment of enteral diseases and as alternatives to parenteral nutrition. Though multiple influences of these diets on the small intestinal bacteria seem possible no long-term studies were hitherto carried out to clarify their actions on the intestinal flora. Therefore, the jejunal flora was assessed qualitatively and quantitatively in a group of rats fed an elemental diet over a period of 60 days and a control group receiving standard pellet food. In both sets of animals similar numbers of colony forming bacteria/ml jejunal juice of the aerobic and anaerobic growing flora were observed. In parallel, the individual genera did not exhibit significant differences in control and experimental animals. According to these findings long-term feeding of a peptide diet to rats does not influence the small intestinal flora.

Animals↗
PubMed1985

A consumer approach to a paediatric assessment clinic.

The past 20 years have witnessed a revolution in the treatment of mentally retarded children. Initially, parents received very little help after the diagnosis was made. Towards the end of the 1960s parents were trained in techniques devised by professionals. A new concept, called the 'consumer model', where parents form an important part of the caring team in selecting a programme best suited to their current needs, is at present developing. With this in mind a survey was carried out by the Assessment Clinic at the Transvaal Memorial Institute for Child Health and Development, Johannesburg, to ascertain parents' needs and their opinions of the service received at the clinic. Thirty-seven parents were interviewed using a structured questionnaire. The results are discussed and the subsequent changes made at the clinic presented. The need for an ongoing evaluation of such a service is emphasized.

Ambulatory Care Facilities↗
PubMed1985

[Significance of deficient bacterial colonization in the pathogenesis of mucosal lesions in experimental blind loop syndrome].

A complete evaluation of the bacterial flora in jejunal self-filling blind loops was performed. The results show a significant increase in bacteria of the genera E. coli, Streptococcus and Bacteroides. In further experiments, jejunal self-filling blind loops were created in germ-free animals. In spite of the germ-free state the mucosa displayed marked hyperplasia. The same was true when the blind loops had been contaminated with aerobic bacteria. These results demonstrate that other factors in addition to bacterial overgrowth contribute to the mucosal damage observed in self-filling blind loops.

Animals↗
PubMed1985

[Quantitative and qualitative determination of the bacterial colonization of the rat jejunum following long-term feeding with an elemental diet].

Elemental diets are increasingly used in the treatment of enteral diseases, but only limited studies have been hitherto carried out to clarify their actions on the intestinal flora. Therefore, the jejunal flora was assessed in rats fed an elemental diet or standard pellet food over a period of 60 days. In both sets of animals similar numbers of colony-forming bacteria per ml intestinal content of the aerobic and anaerobic flora were found. In addition, the individual genera did not exhibit significant differences in control and experimental animals. Thus, long-term feeding with an elemental diet does not influence the jejunal flora of rats.

Animals↗