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Biomedical subjects

T R Beam

Publications and source records attributed to T R Beam.

At least 55 records · Page 3Linked to original sources
PubMed1982

A comparison of the safety, efficacy, and distribution of ceforanide and cephalothin in coronary artery bypass graft surgery.

Antibiotic prophylaxis in open-heart operations is a widely accepted practice. Introduction of new antibiotics with differences in tissue distribution, spectrum of activity and therapeutic index prompts their evaluation as possible effective prophylactic agents. We compared the distribution, clinical efficacy, and safety of ceforanide with cephalothin as a prophylactic agent in coronary artery bypass graft (CABG) procedures. The results indicated that the intravenous administration of ceforanide at the dose of 1 gm every 12 hours for 2.5 days was equivalent to cephalothin 1 gm every 6 hours for 2.5 days. Serum, muscle, and bone concentrations of ceforanide were significantly greater than those of cephalothin. These concentrations consistently exceeded the minimal inhibitory concentration for Staphylococcus aureus, the major pathogen implicated in wound infections. No toxicty was observed with either antibiotic. Ceforanide merits consideration as a prophylactic antibiotic in CABG operations.

Aged↗
PubMed1982

Prevention, diagnosis, and treatment of common infections in geriatric patients.

Prevention of infection in the elderly is far preferable to treatment of the disease, and can be promoted through precautionary measures when undertaking invasive procedures in older patients as well as through the administration of available vaccines. Difficulties in diagnosing bacterial pneumonia, influenza, tuberculosis, diphtheria, tetanus, and urinary tract infections in the elderly, and schedules for treating these diseases, are discussed.

Aged↗
PubMed1981

Trimethoprim-sulfamethoxazole therapy of experimental Escherichia coli meningitis in rabbits.

We used two strains of ampicillin-susceptible Escherichia coli to produce meningitis in rabbits and utilized these models (i) to compare the killing effects of parenteral trimethoprim-sulfamethoxazole (TMP-SMZ) and ampicillin on E. coli in cerebrospinal fluid after 8 h of treatment and (ii) to measure the penetration of TMP-SMZ and ampicillin into cerebrospinal fluid and the brain. At 16 h after intracisternal inoculation with a test strain, rabbits were treated with TMP (6 mg/kg per h) and SMZ (30 mg/kg per h), ampicillin (40 mg/kg per h), or saline intravenously for 8 h. TMP-SMZ levels were measured by high-pressure liquid chromatography, and ampicillin levels were measured by microbiological assay. Mean +/- standard deviation concentrations of TMP, SMZ, and ampicillin in cerebrospinal fluid (mean percent penetration) at the completion of 8 h of therapy were 0.80 +/- 0.41 (18%), 15.7 +/- 21.1 (27.2%), and 2.6 +/- 1.7 (8.9%) microgram/ml, respectively. TMP, SMZ, and ampicillin levels in brain homogenate after 8 h of therapy were 0.23 +/- 0.07 (6.6%), 3.31 +/- 3.3 (5.5%), and 0.6 +/- 4.53 (1.9%) microgram/g, respectively. TMP-SMZ infusion for 8 h produced a significant reduction in mean bacterial counts in cerebrospinal fluid in both models of meningitis compared with saline controls. The decrease in mean bacterial counts with TMP-SMZ therapy was equivalent to that produced by ampicillin.

Ampicillin↗
PubMed1981

Comparison of community-acquired and nosocomial pneumococcal bacteremia.

We evaluated pneumococcal bacteremia retrospectively for 3.5 yr. Sixty-three episodes occurred in 62 patients; 37 were nosocomial in origin; 26 were community-acquired. Pneumococcal bacteremia was most common between January and June. Patients with nosocomial disease had significantly more ultimately fatal disease and sustained more manipulation of the respiratory tract than patients with community-acquired bacteremia. The mortality of nosocomial pneumococcal bacteremia (75.8%) or nosocomial pneumococcal pneumonia with bacteremia (66.7%) was significantly greater than community-acquired bacteremia (26.9%; p less than 0.01) or pneumonia with bacteremia (18.2%; p less than 0.001). All 62 patients were eligible for pneumococcal vaccine, and 57 could have received immunoprophylaxis. A vaccine trial is indicated in the hospital setting.

Cross Infection↗
PubMed1980

Antibody response to polyvalent pneumococcal polysaccharide vaccine in diabetics.

Ten control volunteers and 40 insulin-dependent diabetics were immunized with polyvalent pneumococcal vaccine (Pneumovax). The populations were similar except that diabetics were significantly older. In a double-blind fashion, diabetics were divided into two groups of 20; one received vaccine at baseline and saline placebo four weeks later. The second received saline, then vaccine. Antibody response was measured by radioimmunoassay. In general, insulin-dependent diabetics responded as quickly and equally as controls. Antibody titers did not decline at eight weeks. Incidence and intensity of adverse reactions were similar among diabetics and controls. There was no correlation between antibody response and age (r=-.078), mean glucose concentration (r=-.096), or duration of diabetes (r=-.064). We conclude that insulin-dependent diabetics respond as well as controls to immunization with pneumococcal polysaccharide vaccine.

Antibodies, Bacterial↗
PubMed1980

Amelioration of experimental bacterial meningitis by levamisole: evidence of a direct effect on the infecting bacteria.

The immune-modulating effects of levamisole were evaluated in vivo in rabbits with experimental meningitis due to Escherichia coli and in vitro in assays of ingestive and digestive functions of polymorphonuclear leukocytes. Intracisternal treatment of rabbits with 0.5 ml of levamisole (400 micrograms/ml) 48 and 24 hr before infection resulted in a longer survival time (mean, 49.3 hr) than either control (mean, 21.3 hr; P < 0.01) or intravenously treated animals (mean, 18.3 hr; P < 0.05). However, treatment of the organism by incubation in levamisole (100 micrograms/ml) resulted in survival times significantly longer than that of intracisternally treated animals (mean, 98.5 hr; P < 0.05). A reduction of 5 logs of viable bacteria 22 hr after infection was noted by previous therapy of either the animal or the bacteria. No antibiotic effect was demonstrated. In vitro studies revealed increased ingestion by polymorphonuclear leukocytes (P < 0.02) and digestion (P < 0.05) of bacteria incubated in levamisole. These results suggest that levamisole may alter the bacteria, enhance killing, and produce salutary in vivo effects.

Animals↗
PubMed1980

Comparison of cefamandole, cephalothin, ampicillin, and chloramphenicol in experimental Escherichia coli meningitis.

The activities of cefamandole, cephalothin, ampicillin, and chloramphenicol were compared in fulminant and temperate Escherichia coli meningitis in rabbits. Intensive dosing schedules were employed to achieve maximal therapeutic benefits with short-term treatment. In an 8-h schedule chloramphenicol was significantly more effective in sterilizing the cerebrospinal fluid and curing both fulminant and temperate infections than cefamandole or ampicillin. Cephalothin was without effect in fulminant meningitis. Cefamandole and ampicillin were equivalent in activity in this and longer (12- and 24-hr) treatment schedules. The therapeutic benefits of chloramphenicol were purchased via use of doses above those generally regarded as safe for human use. The mean serum, cerebrospinal fluid, and brain concentrations of chloramphenicol, cefamandole, and ampicillin were significantly greater in rabbits with fulminant meningitis than in those with temperate meningitis. The difference was of such magnitude as to support the need to monitor drug concentrations.

Ampicillin↗
PubMed1980

Therapy of nosocomial infections: past, present and future trends.

There has been a significant increase in the number of bacteremias sustained by hospitalized patients over the past 45 years. Responsible bacterial flora has shifted from streptococcal to staphylococcal to gram-negative. Simultaneously, the patient population has become significantly older. Two types of nosocomial infection are reviewed in this clinical setting. Pneumococcal disease still accounts for 10% of nosocomial pneumonias and 5-10% of nosocomial bacteremias. Antimicrobial therapy, although effective, has not eliminated mortality, particularly among older patients with one or more underlying diseases. Vaccination with pneumonococcal polysaccharide vaccine may reduce the morbidity and mortality associated with this infectious process. Several Pseudomonas vaccines have been evaluated, but none has proven both efficacious and non-toxic. Further development of a gram-negative vaccine, preferably one which protects against several types of bacteria, is required.

Cross Infection↗
PubMed1979

Sequestration of staphylococci at an inaccessible focus.

The persistence of staphylococcal arthritis in a patient treated with nafcillin was attributed to intracellular sequestration of staphylococci. These intraphagocytic organisms were protected against bactericidal activity. The infection was cleared by rifampin--an agent which can penetrate leucocyte membranes. When clinical infections do not respond to seemingly adequate antimicrobial treatment, intracellular persistence of bacteria should be considered.

Adult↗
PubMed1979

Assessment of antibiotic efficacy in acute bacterial meningitis.

Currently, antibiotic efficacy in acute bacterial meningitis is evaluated in several stages. First, animals are used to assess antibiotic penetration into cerebrospinal fluid (CSF) in the absence and presence of an inflammatory stimulus. Second, concentrations of drug are correlated to in vitro killing studies. Third, clinical evaluations compare the new drugs to currently available antimicrobic--but drug failures nevertheless occur, e.g. the experiences with cephalosporins and aminoglycosides. We propose that brain tissue levels of antibiotics are an additional parameter to be monitored. Drugs that penetrate the brain substance should yield higher ventricular concentrations than drugs that penetrate the choroid plexus alone. A protective benefit may also be afforded to brain tissue per se. Experience with chloramphenicol, which penetrates the blood-brain barrier, supports these concepts; so also, do the failures with cephalosporins and aminoglycosides which, despite high CSF concentrations of these agents, afford evidence that currently monitored parameters are inadequate predictors of therapeutic efficacy.

Anti-Bacterial Agents↗
PubMed1979

Patterns of infection in untreated acute leukemia: impact of initial hospitalization.

Several previous authors have examined the association between infection and acute leukemia, especially at the time of death, but none has assessed this problem at the time of diagnosis and initial hospitalization. We have undertaken a retrospective review of cases of acute leukemia diagnosed at the affiliated hospitals of the State University of New York at Buffalo. Results suggest that bacteriologic findings in this population initially resemble those in the general outpatient population. Gram-negative bacilli, especially Pseudomonas aeruginosa, appear as important pathogens after the first week of hospitalization. A statistically significant association with prolonged granulocytopenia and use of antibiotics develops during this course. As a consequence of these data, we recommend careful culture and clinical delineation of the early infection, choosing the narrowest spectrum of antibiotic coverage appropriate to the infection present as data evolve.

Acute Disease↗
PubMed1978

High-performance liquid chromatographic assay of chloramphenicol in serum.

A new method for the analysis of serum chloramphenicol by reversed-phase, high-performance liquid chromatography (HPLC) is described. The method involves a preliminary extraction of 0.1 ml of serum with ethyl acetate containing an internal standard, chromatography with a reversed-phase C18 microparticulate column with an acetonitrile-acetate buffer mobile phase, and detection by measuring UV absorbance at 270 nm. Assay performance was compared with an existing microbiological assay. The HPLC method demonstrated both increased precision and increased sensitivity. The specificity of the HPLC method was also evaluated. The new method presents an alternative approach to the analysis of clinical specimens.

Chloramphenicol↗
PubMed1977

Blood, brain, and cerebrospinal fluid concentrations of several antibiotics in rabbits with intact and inflamed meninges.

Because cerebrospinal fluid (CSF) antibiotic levels fail to predict either clinical success or relapse in the treatment of bacterial meningitis, we examined simultaneous antibiotic concentrations in the blood, brain, and CSF of control rabbits and of animals with experimental pneumococcal meningitis. Cefamandole pharmacokinetics were analyzed in detail and compared with those of cephalothin, ampicillin, penicillin G, and tobramycin. After 4 h of continuous intravenous infusion, cefamandole reached concentrations in both brain and CSF in excess of the minimal bactericidal concentration for the test organism and compared favorably with ampicillin and penicillin in achieving bacteriological cure. Cephalothin levels in the central nervous system remained undetectable in both control and infected animals during this time. Tobramycin concentrations were measurable in the CSF, but not in brain tissue in association with an inflammatory stimulus.

Animals↗