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Biomedical subjects

J E Brorson

Publications and source records attributed to J E Brorson.

At least 55 records · Page 3Linked to original sources
PubMed1981

Branhamella catarrhalis and other bacteria in the nasopharynx of children with longstanding cough.

Nasopharyngeal cultures from 180 children aged 1 to 9 were examined. All children were suffering from cough for at least 10 days. The findings were compared to those from 67 non-coughing children. Bordetella pertussis was isolated from 12.2% of the children in the study group but from none of the control children. Branhamella catarrhalis was isolated from 66.1% of the children in the study group and from 28.3% in the control group (p less than 0.01). Br. catarrhalis was more common in pure cultures from sick children than from control children. Pneumococci were isolated from 20% of the sick children and 28% of the control children. Haemophilus influenzae was isolated from 15% in each group. Some possible interpretations of the findings are discussed.

Age Factors↗
PubMed1981

Studies on some variables influencing aminoglycoside efficacy in vivo and in vitro.

The penetration of various aminoglycosides into uninfected and infected fluids of steel net cages, implanted subcutaneously into rabbits, was studied. The pharmacokinetics of the antibiotics tested in these fluids were characterized by a peak concentration which was delayed in relation to that in serum after both intramuscular and intravenous administration, and by a slower elimination from cage fluids than from serum. Comparing amikacin, gentamicin, netilmicin and tobramycin, the latter seemed to have a somewhat lower penetrability into uninfected cage fluids. Infection of the cage fluids with gram-negative aerobic bacteria resulted in a reduction of the measurable concentrations of amikacin, gentamicin or netilmicin in the cage fluids when compared to those obtained in uninfected fluids in the same rabbits. Elimination of the aminoglycosides from the infected cage fluids was slower than from the uninfected ones. The lower concentrations of the aminoglycosides in infected cage fluids were considered to be primarily due to a penetration barrier created by the infection. The viable counts in infected cage fluids were only marginally affected in cages where the aminoglycoside concentrations were above the minimum inhibitory concentrations (MIC's) of the aminoglycosides against the bacterial strains used for infection when tested in vitro according to standard techniques. In infected cage fluids the pO2 and pH were low, while the pCO2 was high. The number of viable bacteria was high. These factors, which in vitro increased the MIC's of the agents, and the low concentrations achieved in infected cage fluids could explain the inefficacy of aminoglycoside treatment in this experimental model.

Aminoglycosides↗
PubMed1980

Antibiotic sensitivity of Haemophilus influenzae strains including three recent chloramphenicol-resistant isolates.

The antibiotic sensitivity of 100 recent isolates of Haemophilus influenzae was determined. Three strains were resistant to chloramphenicol with minimal inhibitory concentrations of 16 microgram/ml. Of these three resistant strains, one produced betalactamase and one was resistant to sulfamethoxazole-trimethoprim. The remaining strains were inhibited by 0.25-2.0 microgram/ml of chloramphenicol. Ampicillin and benzylpenicillin were found to inhibit all but the betalactamase-producing strains at low concentrations. Regarding sulfamethoxazole-trimethoprim 96% had minimal inhibitory concentrations of 2.5-0.12 microgram/ml or less, while two strains were resistant. The invitro efficacy of erythromycin against H. influenzae was low. The majority of the strains was inhibited by low concentrations of doxycycline and cefuroxime while cefoxitin exhibited minimal inhibitory concentrations values usually exceeding 1 microgram/ml. The minimal inhibitory concentrations registered are compared to the concentrations of the different antibiotics attainable in certain body fluids.

Anti-Bacterial Agents↗
PubMed1980

Empiric treatment of fever in acute leukaemia with tobramycin-cephalothin, and the escape clause provision of corticosteroids.

29 episodes of suspected septicaemia in patients with acute leukemia were treated empirically with tobramycin 180--240 mg/day intravenously together with cephalothin 12 g/day. Patients without documented infection who did not respond to antibiotics and whose fever developed after a course of cytotoxic drugs, were given the provision of high dose corticosteroid therapy. Infection was documented microbiologically or clinically in 13/29 episodes. Septicaemia was proven in 7, and 6 had pneumonia. Neutropenia was present in 18/29 episodes. A satisfactory response to initial therapy was achieved in 7/13 with documented infection and in 9/16 without proven infection. The overall good response was 55%, 5/7 cases with septicaemia, but only 2/6 with pneumonia responded well. The 2 septicaemia patients who did not respond had Pseudomonas aeruginosa sepsis. In 16 episodes without documented infection 7 did not respond to initial therapy. To 4 of them, who were subject to recent cytotoxic drug administration, high dose corticosteroid therapy was given, and 3 of them responded well. Of the remaining 3 non-responders, one became afebrile after cytostatic and one after prednisolone treatment. Serum assays of tobramycin were done on the 1st and 5th day of therapy and no difference in concentration was observed on these 2 occasions. Five patients developed renal failure, but this was attributed to antibiotic therapy only in 1, who initially had an elevated serum creatinine. It is concluded, that in hospitals where pseudomonas is not a dominating pathogen, tobramycin--cephalothin may be a good combination to start empiric therapy with. In patients without proven infection, who have recently been subjected to cytotoxic therapy, and who do not respond to the initial course of antibiotics, a high dose of corticosteroids may be tried, provided the patient is monitored for the hazard of bacterial infection.

Adrenal Cortex Hormones↗
PubMed1979

Comparison between agar and broth minimum inhibitory concentrations of cefamandole, Cefoxitin, and cefuroxime.

The in vitro susceptibility to cefamandole, cefoxitin, and cefuroxime of clinical isolates of Streptococcus faecalis, Klebsiella, and indole-positive Proteus was assayed using minimum inhibitory concentration (MIC) determinations in broth and on solid media. It could be demonstrated that the agar dilution MICs obtained when S. faecalis was tested against cefuroxime and when indole-positive Proteus strains were tested against cefamandole tended to be considerably lower than those obtained with the broth dilution technique. The Klebsiella strains tested did not show any major differences with regard to MICs in broth or on solid media. Using an animal experimental infection model it could be demonstrated that with indole-positive Proteus the higher broth MIC correlated better to the observed data than the lower agar MIC when a beta-lactamase-producing strain was tested. The data obtained indicated that the beta-lactamase of the indole-positive Proteus strain was inducible. The results of the study gave evidence for a risk of false susceptibility of some bacterial species against cefamandole when agar techniques, e.g. paper disk diffusion, are used. For cefuroxime, the same phenomenon can be expected with S. faecalis and to some extent with indole-positive Proteus. In this study, cefoxitin seemed considerably less affected by the technique used for susceptibility testing.

Bacteria↗
PubMed1979

Penetration of cephradine and cefazolin into ulcers of patients suffering from peripheral arterial circulatory insufficiency.

11 patients with peripheral arterial circulatory insufficiency with ulcers on the big toe or on the heel were given 1 g of cephradine intravenously (i.v.) and later 1 g of cefazolin i.v., two cephalosporins with different degrees of protein binding. Antibiotic concentrations were followed in serum and wound secretions after the injections. The peripheral circulatory state of the patients and the degree of protein binding of the cephalosporins used seemed to be of minor importance for the concentrations of the antibiotics in the ulcers, i.e. the infectious focus, compared to local factors such as the bacterial flora of the ulcers. In-vitro studies with bacterial strains isolated from the ulcers of 2 of the patients indicated that beta-lactamases from gram-negative bacteria might be at least part of the explanation for the low concentrations in wound secretion of one or other of the agents used in 4 out of the 11 patients.

Aged↗
PubMed1978

Studies on the pharmacokinetics of cefoxitin, cefuroxime, cephaloridine and cephalothin using subcutaneous tissue cages.

The present study was undertaken to compare the ability of three cephalosporins--cephalothin, cephaloridine and cefuroxime--and a cephamycin--cefoxitin--to penetrate into extravasal compartments. The study was performed using female adult rabbits with subcutaneously implanted steel net cages. All antibiotics were given in a dose of 50 mg/kg b.w. parenterally as i.v. injections. The concentrations of the different antibiotics were determined simultaneously in serum and in fluid obtained from the cages. The concentrations were followed after single doses as well as after repeated doses using an agar well technique for the assays. To control the experimental conditions electrolyte and protein contents of the fluid in the different cages were followed and were found to be stable during the experimental period. All antibiotics were rapidly eliminated from serum. The concentrations in the cages reached its maximum 1.5-3 hours after administration. The highest concentrations in the extravasal compartments were obtained with cephaloridine and the lowest with cephalothin with the values of the other antibiotics ranging in between.

Animals↗
PubMed1976

Studies on Branhamella Catarrhalis (Neisseria catarrhalis) with special reference to maxillary sinusitis.

Paired sera from 97 patients with acute maxillary sinusitis were examined regarding antibodies to Branhamella catarrhalis. Precipitating antibodies were demonstrated in almost all sera both from patients and from healthy blood donors. Complement-fixing (CF) antibodies to B. catarrhalis were present in sera from 25 of the 97 patients and in one of 20 healthy blood donors. The titres were low and the titre changes when present were of a small magnitude. CF antibodies were most commonly demonstrated in the younger age groups. The patients with demonstrable CF antibodies to B. catarrhalis did not differ from patients without antibodies regarding radiological appearance or healing during therapy. Strains of B. catarrhalis were all rapidly killed by normal human serum but not in heated sera. The strains could not multiplicate significantly at an oxygen tension corresponding to about half the atmospheric value. The possible significance of the serological and bacteriological findings is discussed.

Acute Disease↗
PubMed1975

Properties of some staphylococcus aureus strains associated with spontaneous l-phase transformation.

Spontaneous L-phase production was found in 7 of 14 investigated Staphylococcus aureus strains. A common characteristic of the strains producing L-phase variants spontaneously was their ability to develop L-colonies on a solid medium with 1.0-1.5% NaCl by the action of methicillin, whereas other strains required higher NaCl concentrations. Further, in 6 of the 7 strains the ability for spontaneous L-phase production was associated with high L-phase productivity in the presence of methicillin. The pattern of alpha-, beta- and delta-hemolysin production in a strain was not correlated to spontaneous L-phase production.

Hemolysin Proteins↗
PubMed1975

Prolonged survival of non-multiplying Staphylococcus aureus cells undergoing autolysis in the presence of certain inhibitors of cell wall synthesis.

Certain antibiotic compounds including penicillin, cloxacillin and 6-APA caused a prolonged survival of Staph. aureus cells undergoing autolysis in physiologic saline. The retardation of the death rate was dependent upon the type of compound and its concentration. The results suggest that the compounds inhibit the autolytic function of the bacteria.

Autolysis↗
PubMed1975

Some clinical, immunological and bacteriological observations in a case of pyogenic arthritis due to bacteroides fragilis.

A case of recurrent pyogenic arthritis in a knee joint and abscess formation of the lower limb is described. The infection occurred in a 70-year-old male patient treated with steroids for rheumatoid arthritis. A strain of Bacteroides fragilis was repeatedly isolated both from the knee joint and the abscess. The isolated strain was used as antigen in tube agglutination tests and significant titre changes were observed during the course of the disease. The isolated strain was initially sensitive to doxycycline but developed resistance to this drug during therapy. The sensitivity to lincomycin remained unaffected.

Aged↗