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Biomedical subjects

T R Beam

Publications and source records attributed to T R Beam.

At least 37 records · Page 2Linked to original sources
PubMed1989

Ceftriaxone disposition in open-heart surgery patients.

The effects of cardiopulmonary bypass (CPB) with hypothermia and systemic heparinization on ceftriaxone disposition were evaluated in seven male patients. A bolus dose of drug (14 mg/kg of body weight) was given, and blood and urine specimens were collected before, during, and after CPB for 96 h. Creatinine, albumin, and total and free ceftriaxone concentrations in plasma were measured. The ceftriaxone free fraction (ff) in vitro was estimated by equilibrium dialysis, and the in vivo ff was obtained by the ratio of renal clearance due to filtration to creatinine clearance. Pharmacokinetic parameters were based on concentrations of total drug and free drug. Albumin decreased from 3.10 +/- 0.29 g/dl presurgery to 1.42 +/- 0.17 g/dl and recovered to 2.46 +/- 0.26 g/dl on postoperative day 4. CPB markedly increased the in vitro ff, which was reversed by protamine post-CPB (ff pre-CPB, 0.15 +/- 0.01; during CPB, 0.53 +/- 0.20; post-CPB, 0.16 +/- 0.02). The in vitro ff exceeded the in vivo ff (0.53 +/- 0.20 versus 0.24 +/- 0.07), probably due to continued free fatty acid release caused by heparin during dialysis. Clearances based on free drug decreased, and the renal clearance due to filtration increased (7.6 +/- 2.8 versus 15.0 +/- 4.5 ml/min) while the creatinine clearance decreased (114 +/- 29 versus 72 +/- 28 ml/min) during CPB. Diminished binding owing to low albumin and free fatty acids explain this behavior. Lower binding also increased the volume of distribution (154 +/- 41 ml/kg) and extended the half-life (15 +/- 6 h). In summary, ceftriaxone disposition was significantly altered by CPB, resulting in marked increases in free drug concentrations, half-life, and volume of distribution and in decreased intrinsic clearance.

Aged↗
PubMed1989

Routine screening for syphilis is justified in patients admitted to psychiatric, alcohol, and drug rehabilitation wards of the Veterans Administration Medical Center.

Of 1515 patients admitted to psychiatric, alcohol, and drug rehabilitation services in the Veterans Administration Medical Center, Buffalo, NY, during the year 1987, who were screened by serologic tests for syphilis, 16 (1.05%) had positive rapid plasma reagin and fluorescent treponemal antibody-absorption tests for syphilis. A positive serologic test result was not suspected on clinical grounds in any of these patients. All were detected by routine screening. Of the 16 patients, 15 had charts available for review. Seven patients were treated for primary or late syphilis; four patients had received previous treatment; and four patients had no evaluation of test results and received no treatment. Routine screening of hospitalized patients who are alcohol or drug abusers is justified, but close follow-up is necessary to make screening meaningful.

Adult↗
PubMed1988

Long-term evaluation of the hepatitis B vaccine (Heptavax-B) in hemodialysis patients.

Hemodialysis patients were screened for hepatitis B surface antibody (anti-HBs) prior to immunization at two teaching hospitals. Thirty-one of 111 patients (28%) had baseline sera positive for anti-HBs, while anti-HBs was found in 30 of 420 (7.1%) health care employees (P less than 0.001). A total of 72 hemodialysis patients (mean age, 55.7), received the hepatitis B vaccine (Heptavax-B, Merck Sharp & Dohme, West Point, PA). The responder rates (34 of 72; 47%) and nonresponder (38 of 72; 53%) rates were similar to previous reports. Neither age (P greater than 0.05) nor injection site (P greater than 0.05) appeared to influence results. Nonresponders (16 of 17; 94%) who were given a fourth vaccine dose also failed to mount an antibody response. Of the 34 responders, 18 were followed by serial anti-HBs determinations. Seven transient responders (7 of 18; 39%) were identified, and anti-HBs fell below 10 S/N (sample/control counts per minute) within 12 to 15 months of the first vaccine dose. A fourth dose was administered to this group and it extended the presence of serum anti-HBs (S/N greater than or equal to 10) in four of six patients for another 2, 8, 10, and 15 months, respectively. Antibody persisted but declined over the study period in the remainder of responders followed serially (11 of 18; 61%). When compared with those responders who lost anti-HBs, those with persistent antibody had higher anti-HBs values at 7 (P less than 0.02) and 12 months (P less than 0.005) after the first injection, and were younger (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Treatment failures of cefotaxime and latamoxef in meningitis caused by Enterobacter and Serratia spp.

Despite the apparent success of several new cephalosporins in the treatment of Gram-negative bacterial meningitis, four treatment failures with cefotaxime or latamoxef were encountered (two caused by Enterobacter and two by Serratia spp.) In-vitro parameters of susceptibility of these clinical isolates were compared with those of a meningeal Ent. cloacae isolate from a successfully treated patient. The MIC and MBC values, degrees of inoculum effect, and amounts of beta-lactamase produced correlated poorly with the observed clinical outcome. However, the extent to which an isolate was killed by the cephalosporin used for treatment, in a 6-h in-vitro incubation, showed good correlation. We suggest that such a test should be used to predict clinical outcome of therapy because the other parameters such as the MIC and MBC values are not sufficiently discriminatory.

Adult↗
PubMed1987

Routine culturing for Legionella in the hospital environment may be a good idea: a three-hospital prospective study.

The source for nosocomial Legionnaires' disease is the water distribution system. However, the implications for legionella contamination in a hospital without known Legionnaires' disease is unclear. Therefore, culturing for Legionella pneumophila in the environment has not been routinely recommended. The authors conducted a prospective pneumonia study in three hospitals, none of which was known to have a major problem with endemic legionellosis. The water system of Hospital 1 was colonized with L. pneumophila, serogroup 1; Hospital 2 was colonized by L. pneumophila, serogroup 5 (which is rarely associated with disease); Hospital 3 was essentially free of L. pneumophila. Sputum culture on selective legionella media, direct fluorescent antibody testing, and serology were performed for all nosocomial pneumonias regardless of clinical impression. At the end of the study the incidence of nosocomial legionnaires' disease was found to be 9%, 0%, and 0% in Hospitals 1, 2, and found to be 9%, 0%, and 0% in Hospitals 1, 2, and 3, respectively. In Hospital 1, monoclonal antibody subtyping confirmed that the patient isolates were identical to the environmental isolates. The authors conclude that environmental culturing, despite the absence of known Legionnaires' disease, is useful. Positive cultures from the hospital water supply would mandate the introduction of legionella testing into the laboratory and stimulate physicians to consider Legionnaires' disease when encountering nosocomial pneumonias.

Cross Infection↗
PubMed1987

Preventing infection in open heart surgery.

The risks for infection following open heart surgery may be divided into three components: the environment, operating room personnel, and the patient. Critical appraisal of the available literature yields the following conclusions. First, the environment may result in fungal or bacterial contamination of the surgical wound or mucosal surfaces. However, it is infrequently possible to prove that such contamination causes infections. Second, personnel may contaminate the patients, but rarely do so. Third, the patient's endogenous flora is most often the source of infecting bacteria. Proper preoperative preparation and judicious use of prophylactic antibiotics minimize the risk of infection.

Anti-Bacterial Agents↗
PubMed1986

Aztreonam concentrations in human tissues obtained during thoracic and gynecologic surgery.

The concentrations of aztreonam in human tissues obtained during surgery were measured after a single 2-g intravenous dose. The average concentration in the skeletal muscle, atrial appendage, lung, sternum, pericardial fluid, endometrium, myometrium, fallopian tube, and ovary varied from 3 to 33 micrograms/g (or microgram/ml). These concentrations significantly exceed the MIC for 90% of strains for most members of the family Enterobacteriaceae.

Aged↗
PubMed1985

Safety and pharmacokinetics of ceftazidime in patients with chronic hepatic dysfunction.

Safety and pharmacokinetic parameters of ceftazidime were evaluated in twelve male volunteers mean age 54.6 +/- 9.2 years. All had chronically impaired hepatic function which remained stable or normalized during ceftazidime administration. There was neither nephrotoxicity nor haematological toxicity. Serum concentration time curves of ceftazidime exhibited a biexponential decline. Drug accumulation was not apparent. Following doses 4 and 13, mean serum half-lives were 2.8 and 2.9 h, volumes of distribution 0.15 +/- 0.04 l/kg and 0.17 +/- 0.041 l/kg and plasma clearance values 1.320 +/- 0.50 ml/min/kg and 1.096 +/- 0.48 ml/min/kg, respectively. Dose modification based on hepatic dysfunction is unnecessary.

Ceftazidime↗
PubMed1984

Comparison of ceftriaxone and cefazolin prophylaxis against infection in open heart surgery.

One hundred four patients undergoing elective open heart surgery were enrolled in a prospective, double-blind trial comparing prophylaxis against infection using a single 1 g dose of ceftriaxone and seven doses of cefazolin. Patients in both groups had similar risk factors for infection. The likelihood of achieving a tissue concentration in excess of the minimal inhibitory concentration for Staph. aureus was significantly greater with ceftriaxone in atrial appendage (p less than 0.001), muscle (p less than 0.01), and bone (p less than 0.01) than with cefazolin. The serum half-life of ceftriaxone was approximately 15.7 hours. All 49 serum samples obtained 18 to 24 hours after delivery of ceftriaxone and 26 of 33 samples obtained 40 to 48 hours after delivery had drug concentrations in excess of 3.1 micrograms/ml, the mean minimal inhibitory concentration for isolates of Staph. aureus. Early and late infectious complications were infrequent and occurred at similar rates in both groups. Neither drug was associated with significant toxicity. A single 1 g dose of ceftriaxone was as effective and safe as multiple doses of cefazolin and demonstrated superior tissue penetration.

Aged↗
PubMed1984

Cross allergenicity between penicillins and cephalosporins.

Twenty patients excluded from pre-marketing trials of cephalosporin antibiotics as chemoprophylaxis for open heart surgery were enrolled in an evaluation of skin-test reactivity. All gave a history of type I hypersensitivity to penicillins. None knew of adverse reactions to cephalosporins. Eighteen were negative to testing with saline, cefazolin, ceftriaxone, penicillin G and benzyl-penicilloyl. Two patients with positive skin tests safely received vancomycin chemoprophylaxis. We conclude that most patients who give a positive allergic history but have negative skin tests can safely receive cephalosporin chemoprophylaxis.

Cephalosporins↗
PubMed1984

Streptococcus pneumoniae meningitis in two patients with peritoneovenous shunts.

We report two patients with cirrhosis and peritoneovenous shunts (LeVeen) in whom fatal Streptococcus pneumoniae sepsis and meningitis developed 10 months and 22 days, respectively, after insertion of the shunts. The association between pneumococcal bacteremia and meningitis is well established. The potential implications of a LeVeen shunt in increasing risk for meningitis are discussed.

Aged↗
PubMed1983

Systemic infections treated with amdinocillin in combination with other beta-lactam antibiotics.

Amdinocillin is a semisynthetic derivative of 6-beta-amidinopenicillanic acid, which has bactericidal activity against a broad spectrum of gram-negative bacteria. We report the results of a multicenter study evaluating the safety and efficacy of amdinocillin in combination with other beta-lactam antibiotics in the treatment of 120 serious gram-negative bacterial infections. Amdinocillin was safe and well tolerated and, in combination with other beta-lactam antibiotics, was effective in the treatment of a broad range of gram-negative bacterial infections. Therapy with amdinocillin and other beta-lactam antibiotics was often associated with a demonstrable synergistic effect. Thus, amdinocillin holds promise as an effective antibiotic with synergistic potential when used in combination with penicillins and cephalosporins.

Amdinocillin↗
PubMed1983

Staphylococcus aureus bacteremia: a prospective study.

During a 22-month period, 47 patients with 49 consecutive episodes of Staphylococcus aureus bacteremia were identified and observed prospectively for the development of endocarditis and metastatic infection. Eighteen (37%) of the episodes were community-acquired and 31 (63%) were nosocomial. The mean patient age was 55 years, and all but nine patients had one or more underlying diseases. A primary focus was identified for 38 episodes (78%) most often an intravenous catheter, and 21 episodes (43%) were associated with a removable focus of infection. In this group, no patient had endocarditis after a mean duration of 20 days of therapy. Overall, two of 47 patients had endocarditis by clinical criteria; one was a drug abuser and one had no known heart disease. Forty-five of 49 episodes were treated with a single antimicrobial agent. There were 12 (24%) deaths in this series, seven (14.2%) directly due to staphylococcal infection. In this prospective study we found a low but definite risk of endocarditis associated with S aureus bacteremia. The mortality was similar to that in other recently published studies. All deaths occurred within two weeks of initiating therapy, indicating the potential importance of host factors in the outcome.

Adult↗
PubMed1983

Recent developments in antimicrobial therapy with beta-lactam antibiotics.

There are three new penicillin and three new cephalosporin compounds available in the United States. All have been developed via biochemical manipulation of the beta-lactam ring and its adjacent chemical groups. The antibacterial spectrum of activity has been greatly expanded. Each of the six new agents has a unique antimicrobial profile which mandates independent evaluation. Therapeutic use of these drugs, particularly in treatment of gram-negative meningitis, has yielded success rates not previously witnessed. Application of these antibiotics as prophylactic agents for surgical procedures remains controversial. Guidelines are offered to distinguish one agent from another based on antimicrobial, pharmacokinetic and toxicologic properties.

Anti-Bacterial Agents↗
PubMed1983

New concepts of pathogens, and pathogenesis.

Recent changes in thinking about the host-parasite relationship are reviewed. New agents have been identified as respiratory and urinary tract pathogens. Agents previously considered benign, eg., Staphylococcus epidermidis, have become increasingly important causes of disease. Finally, studies on patients with the acquired immune deficiency syndrome have yielded important new information about both host defenses and pathogens. Continued investigation should provide important data which expand the understanding of what causes an infection and the factors responsible for disease.

Acquired Immunodeficiency Syndrome↗