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Biomedical subjects

M Bal

Publications and source records attributed to M Bal.

33 records · Page 2Linked to original sources
PubMed1992

Temporal arteritis in a northwestern area of Spain: study of 57 biopsy proven patients.

Fifty-seven patients, diagnosed with temporal arteritis by biopsy from 1981 to 1990, were studied. The average annual incidence rate/100,000 population aged 50 and older, which was slightly lower than those from other Mediterranean countries of Europe, was 6. Apart from a predominance of males, age, clinical and laboratory features were similar to those reported from other parts of the world. All patients received corticosteroid therapy, the majority of them recovered completely. Fifty-four were followed; 34 had already finished treatment (mean: 22 months, range: 12-50). Relapses occurred more commonly after 12 months of therapy, when the amount of prednisone given was low or discontinued.

Aged↗
PubMed1989

A new method of plasmid DNA preparation by sucrose-mediated detergent lysis from Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive).

A simple and cheap method of plasmid DNA preparation from both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) organism is presented here. In this method, in place of the high-priced chemicals lysostaphin and lysozyme which are commonly used for removal of cell-wall during plasmid DNA preparation from gram-positive and gram-negative bacteria, respectively, only sucrose has been used. Firstly, bacteria is treated with Trizma (pH 8.0) containing 100% sucrose (hypertonic solution). Due to this osmotic shock, protoplasm covered by the plasma membrane of bacteria possibly shrinks and becomes detached from the cell-wall. Osmotically sensitive cells thus formed, from gram-positive (S. aureus) and gram-negative (E. coli) bacteria, are finally lysed by the lysis mixture, containing brij 58 and sodium deoxycholate. The lysate is centrifuged at 15,000 rpm for 30 min to pellet the cell debris. The supernatant containing plasmid DNA is treated with either polyethylene glycol or isopropanol. The precipitate which contains plasmid DNA is dissolved in a buffer containing Tris, EDTA, NaCl, and sodium dodecyl sulfate (pH 8.0); thus protein is denatured and removed. Finally, RNA is removed by RNase treatment. The average yield of staphylococcal plasmid DNA as well as plasmid pBR322 from E. coli HB101 in 100% sucrose-treated preparations is greater than that of lysostaphin- and lysozyme-treated preparations. This method is applicable for both large-scale and small-scale preparations. The substrate activity for restriction enzyme, cloning, transforming ability, and electron microscopic profile of the plasmid DNA prepared by this method remains unaltered.

Cell Wall↗
PubMed1989

Epidemiology of the Bacteroides fragilis group in the colonic flora in 10 patients with colonic cancer.

We report the relative frequencies of members of the Bacteroides fragilis group in the faeces, in colon lavage fluid obtained pre-operatively, and in colonic tissue specimens obtained at operation from 10 patients with colonic cancer. B. vulgatus was the most and B. fragilis and B. ovatus were the least frequently isolated Bacteroides spp. in the faeces of the 10 subjects. B. uniformis and B. thetaiotaomicron ranked second and third in the faeces. The relative frequencies of all species except B. fragilis were lower in the lavage fluid and in cultures of mucosa. The relative frequency of B. fragilis increased from 4% in faeces to 39% in the final lavage fluid and to 42% in the colonic mucosa culture. Our results suggest that B. fragilis has a more intimate association with the gut mucosa than other members of the B. fragilis group, which might be one explanation for the high incidence of this species in gut-associated intra-abdominal infections.

Adult↗
PubMed1987

Effect of Bacteroides fragilis cellular components on chemotactic activity of polymorphonuclear leukocytes towards Escherichia coli.

Chemotaxis of polymorphonuclear leukocytes (PMNL) in response to cell components of Bacteroides fragilis alone or in combination with Escherichia coli was evaluated. E. coli produced much more powerful chemotactic factors than B. fragilis. The culture filtrate (CF), outer membrane (OM) preparation, and lipopolysaccharide (LPS) of B. fragilis slightly stimulated chemotactic activity of PMNL. The culture filtrate and OM preparation were capable of inhibiting the chemotaxis of PMNL in response to the chemotactic factors of E. coli but LPS of B. fragilis was not able to do so. Reduction by B. fragilis of PMNL chemotaxis in response to E. coli was not specific for B. fragilis but also occurred in the presence of facultative bacteria. In parallel with chemotaxis, lysozyme release, but not beta-glucuronidase release, by PMNL was significantly stimulated by E. coli but not by B. fragilis.

Bacterial Outer Membrane Proteins↗
PubMed1986

Effect of Bacteroides fragilis grown in the presence of clindamycin, metronidazole and fusidic acid on opsonization and killing of Escherichia coli.

Bactericidal action of human polymorphonuclear leucocytes on Escherichia coli in the presence of Bacteroides fragilis grown in subinhibitory concentrations of clindamycin, metronidazole and fusidic acid was studied. Bacteroides fragilis grown in the absence of drugs significantly inhibited the killing of Escherichia coli. Bacteroides fragilis grown in the presence of the drugs had a reduced inhibitory effect on the killing of Escherichia coli but this reduction was only significant for Bacteroides fragilis grown in 1/2 MIC of clindamycin. The phagocytosis of Bacteroides fragilis grown with and without clindamycin, as measured by killing, was the same. Complement consumption of Bacteroides fragilis grown with and without clindamycin did not differ. Clindamycin-treated Bacteroides fragilis fixed C3 to a significantly lower degree than did untreated bacteria. The chemiluminescence of Escherichia coli opsonized with serum preincubated with clindamycin-treated Bacteroides fragilis was significantly higher than with serum preincubated with untreated bacteria. These results suggested that in killing experiments of mixed Escherichia coli and Bacteroides fragilis, the mechanism underlying the reduced inhibitory capacity of clindamycin-exposed Bacteroides fragilis is related to greater availability of C3 in serum for opsonization of Escherichia coli.

Anti-Bacterial Agents↗
PubMed1984

Polymorphonuclear leukocyte chemotaxis by mixed anaerobic and aerobic bacteria.

The induction of chemotactic activity of polymorphonuclear leukocytes (PMNL) by anaerobic and aerobic bacteria alone or in combination was evaluated. Washed cells as well as the supernate of Proteus mirabilis were chemotactic for leukocytes. The supernate of cultures of two strains of Bacteroides fragilis contained small amounts of chemotactic factors. No chemotactic factors were released from the non-fragilis Bacteroides strains. The supernates of cultures of anaerobic bacteria were capable of inhibiting chemotaxis of leukocytes to the chemotactic factors of P. mirabilis. P. mirabilis and two strains of B. fragilis generated chemotactic factors in serum but none of the other Bacteroides spp. tested were able to induce serum chemotactic factors.

Adult↗
PubMed1983

Effect of anaerobic bacteria on killing of Proteus mirabilis by human polymorphonuclear leukocytes.

Killing of Proteus mirabilis by human polymorphonuclear leukocytes was tested in the presence of different Bacteroides species. In vitro experiments showed that anaerobic bacteria interfered with the killing of aerobic bacteria. However, this inhibitory effect was not a property of all Bacteroides species. Bacteroides gingivalis W83 showed the greatest inhibitory effect of the five Bacteroides strains tested. Killing of P. mirabilis was inhibited by the culture supernatant of B. gingivalis but not by washed cells. Two factors were found in the supernatant of B. gingivalis to account for the inhibitory effect. One was heat stable with a molecular weight of less than 3,500 and inhibited the killing activity of leukocytes, and the other was heat labile and partly inactivated the complement system. The killing experiments paralleled chemiluminescence measurements.

Bacteroides↗