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Biomedical subjects

D Baron

Publications and source records attributed to D Baron.

At least 91 records · Page 5Linked to original sources

Pharmacokinetics of norfloxacin in the elderly.

9 elderly and 9 younger adult patients, with proven post-operative lower urinary tract infection were treated with 400 mg of norfloxacin twice daily for 5 days. Pharmacokinetics of norfloxacin were measured on days 1 and 5. Compared to the younger adult patients, the elderly showed a decreased creatinine clearance and, following the last dose on day 5, an increased maximum plasma concentration of norfloxacin, an increased area under the concentration-time curve and a decreased total body clearance of norfloxacin. These results confirm that in elderly, as in younger adult patients, the pharmacokinetics of norfloxacin can be described by a linear model and accumulation of the drug during repetitive multiple doses is predictable. The differences between the two groups cannot be considered as clinically significant so that no dose change would be required in elderly patients within the range of creatinine clearance studied.

Age Factors↗

Impact of dosage schedule on the efficacy of gentamicin, tobramycin, or amikacin in an experimental model of Serratia marcescens endocarditis: in vitro-in vivo correlation.

Aminoglycosides are usually considered to be concentration-dependent antibiotics and to have similar pharmacodynamic and pharmacokinetic properties. To verify the equivalent activity of the aminoglycosides on a susceptible strain, we tested the killing rate of three aminoglycosides (gentamicin, tobramycin, and amikacin) on one strain of Serratia marcescens both in vitro and in vivo by using a rabbit model of left-ventricle endocarditis. Despite, similar MICs, the time-kill curve of gentamicin was consistently better than those of amikacin and tobramycin, whatever the concentration of each antibiotic used (1, 2, 4, 8, 16, or 32 mg/liter), after a 5-h incubation. The in vivo bacterial reduction in the vegetations was measured 24 h after administration of an intravenous 48-mg/kg bolus of each antibiotic or at the end of a 24-h continuous intravenous infusion of the same dose. Gentamicin was significantly more effective when administered as a bolus than when administered as a continuous infusion (2.8 +/- 0.2 versus 6.4 +/- 1.5 log10 CFU/g of vegetation, respectively; P less than 0.01), whereas amikacin was more effective as a continuous infusion than as a bolus injection (3.6 +/- 2.0 versus 7.5 +/- 1.3 log10 CFU/g of vegetation, respectively; P less than 0.01). Tobramycin was not very effective, whatever the dosage tested (approximately 6.5 to 7 log10 CFU/g). These results suggest that concentration-dependent bactericidal activities, both in vitro and in vivo, may vary greatly among aminoglycosides despite similar MICs.

Amikacin↗

Washed human platelets prevent ischemia-reperfusion edema in isolated rabbit lungs.

Washed human platelets prevent edema formation in isolated rabbit lungs infused with xanthine oxidase, an enzyme that injures endothelial membranes by generating extracellular oxidants. We hypothesized that platelets would similarly preserve membrane permeability in isolated lungs exposed to ischemia-reperfusion injury, a model that perturbs endothelial cells by the generation of intracellular oxidants. Isolated perfused rabbit lungs (IPL) were exposed to warm ischemia-reperfusion to cause lung edema. The infusion of washed human platelets (1.05 +/- 0.02 x 10(10) cells) prevented edema formation as measured by lung weight gain, wet-to-dry lung weight ratios, histological edema, and preservation of paraendothelial cell tight junctions. Inhibition of the platelet glutathione redox cycle with 1,3-bis(2-chloroethyl)-1-nitrosourea, dehydroepiandrosterone, or 1-chloro-2,4-dinitrobenzene interfered with platelet protective effects. In contrast, inhibition of platelet catalase with aminotriazole and H2O2 had no effect on platelet protection. Lung tissue malonyldialdehyde concentrations were similar in isolated lungs exposed to ischemia-reperfusion with or without the infusion of platelets. These results indicate that platelet attenuation of ischemia-reperfusion lung edema depends on platelet glutathione redox cycle antioxidants but not platelet catalase.

Animals↗

Group psychotherapy for HIV-seropositive patients with major depression.

Patients were recruited from the UCLA AIDS Research Center who had previously been referred to psychiatry for participation in an open-label pilot treating patients with major depression with fluoxetine. They chose to participate in group therapy for continuing distress in coping with their HIV-seropositive status, dissolution of their support system, "accepting patienthood," and on being placed on an experimental medical protocol. The group was a closed, twenty-session, homogeneous (for patient characteristics), psychoeducational, supportive, and cognitively oriented psychotherapy group. We found this to be a successful intervention in helping patients manage HIV illness and in providing the coping skills and social support necessary to function at home, work, and in their interaction with their health care providers.

AIDS-Related Complex↗

[Fixation of Indium111-labeled antifibrin monoclonal antibody on the vegetation in endocarditis: evaluation in a rabbit model].

The uptake of a 111In labelled antifibrin antibody was studied in left ventricle endocarditis on a rabbit model. The immunospecificity of the antibody for the cardiac vegetations is favorable, exhibiting an uptake at least 4 times that of blood, or myocardium. A planar scintigraphy of the opened left ventricle showed a radionuclide imaging of vegetations, according to anatomical lesions. The use of antifibrin monoclonal antibodies could prove helpful to improve the specificity of valvular lesions visualized by echocardiography, or to detect the small vegetations at the early stage of acute endocarditis.

Animals↗

Evaluation of indium-111-labeled antifibrin monoclonal antibody for the diagnosis of venous thrombotic disease.

The potential advantage of using 111In-antifibrin (111In-AF) monoclonal antibody for the diagnosis of deep venous thrombosis (DVT) was studied in 44 patients with suspected DVT (27 underwent heparin therapy before 111In-AF injection). All patients had contrast venography (considered as the gold standard) and 111In-AF scintigraphy within 24 hr. Two to 3 mCi of 111In-AF were injected intravenously, and planar scintigraphy of the limbs was recorded within 10 min (17 times), 3 hr (44 times), and 18 hr (39 times). Indium-111-AF images were then interpreted without knowledge of the results of the other examinations. The DVT diagnostic accuracy of 111In-AF was greater when interpretation was based on images recorded at different time periods after injection. Indium-111-AF sensitivity for diagnosis of DVT was 85% (29/34) and was not apparently decreased by heparin therapy. None of the 10 patients with negative contrast venography had a positive 111In-AF scan. The results demonstrate the importance of recording serial images and the excellent accuracy of 111In-AF for diagnosing DVT.

Antibodies, Monoclonal↗

[Industrial production of monoclonal antibodies].

Murine monoclonal antibodies (mabs) are produced in either mouse ascites or bioreactors (spinner culture, stirred-tank reactor, airlift reactor, hollow-fiber reactor). Human mabs are produced solely in bioreactors. Encapsulation represents a special technology. Hybridoma cells have to be adapted prior to growth in bioreactors. Of crucial importance is the construction of over-producing cell lines by cell- and gene-technological methods. Manipulated cell lines often produce modified mabs.

Animals↗

[Monoclonal antibodies and mediators--immunologic tumor therapy].

Immunological tumor therapy includes the use of interferons, interleukins, tumor necrosis factor, and monoclonal antibodies. Clinical tests performed on about 20 types of solid tumors and 10 types of leukemias and lymphomas showed rather limited success. In many cases the side effects are considerable, resulting in the interruption or cessation of therapy. Improvements can be achieved by gene technology. Only the interferons have been approved as official drugs to treat cancer.

Antibodies, Monoclonal↗

[Study of incidence and risk factors of nosocomial urinary tract infection in patients with indwelling urinary catheter in intensive care units].

A prospective study was carried out in a medical and surgical ICU to determine the incidence of nosocomial urinary tract infection (NUTI) and to identify the most important risk factors. Over a 6 month period, 180 patients were included. All had an indwelling catheter. Six risk factors were studied: age, sex, illness (medical, surgical, trauma), hospital or extra-hospital origin, simplified acute physiology score and length of bladder catheterization. Forty three patients developed a NUTI. Length of bladder catheterization was the only significant different risk factor in infected and non-infected patients. Kaplan Meir analysis was used to determine time to development of NUTI. The risk rose from 19% for 5 day long catheterization to 50% for 14 day long catheterization.

Adult↗

Pharmacokinetics of teicoplanin in burn patients.

The pharmacokinetics of teicoplanin were studied in 21 adult burn patients and in 5 healthy controls. All subjects were given a single dose of teicoplanin, 10 mg/kg i.v. The pharmacokinetic parameters of teicoplanin were calculated using a tri-exponential model. Three parameters were investigated--burn surface area, creatinine clearance and time of administration after injury (3 days, 8-10 days and 15-20 days respectively). The elimination half-life was not significantly different between the control group (47 +/- 6 hours), the group with a burn surface area greater than 40% (64 +/- 38 hours), and the group with a burn surface area of 25-30% (44 +/- 15 hours). Trough serum concentrations at 12 hours were consistently less than 8 mg/l in all groups. There was some degree of correlation between creatinine clearance and renal clearance of teicoplanin (p = 0.03; r = 0.44). However, there was no correlation between burn surface area and creatinine clearance, or between the time of administration and creatinine clearance. Non-renal clearance of teicoplanin was unaffected by a large burn surface area. The conclusions from this study are as follows. Burn surface area and time of administration after injury are not predictive factors for the determination of an appropriate dose regimen. Trough serum concentrations at 12 hours emphasize the need for a further intravenous bolus. Burn patients with a high creatinine clearance (greater than 140 ml/min) should be carefully monitored.

Adult↗

[Comparative study of two protocols of antibiotic prophylaxis in endoscopic urologic surgery].

We report an open, prospective, randomized and double-blind study which compared two groups of patients without preoperative bacteriuria, undergoing transurethral urologic surgery. A first group received cefazoline 3 g perioperatively and a second group a single preoperative dose of cefotiam 1 g. A hundred patients were included in each group which were well matched on all essential characteristics, risk factors, surgery, anesthesia and postoperative temperature. The incidence of postoperative infection (bacteriemia and bacteriuria) was the same in both groups (16%). It is concluded that in transurethral urologic surgery performed in patients without preoperative bacteriuria, 1 preoperative dose cefotiam is as efficacious as 3 perioperative doses cefazoline.

Aged↗

A report of eight HIV-seropositive patients with major depression responding to fluoxetine.

This pilot study examined the effectiveness of fluoxetine in depressed human immunodeficiency virus (HIV)-seropositive asymptomatic patients. Eight patients, participating in an AZT trial who met criteria for major depression syndrome (DSM-III-R), were treated with fluoxetine (20 or 40 mg/day) for 4 weeks. Initially, mean Hamilton Depression scores were 23.8 (range of 17-31), and improved to 6.4 (range of 3-10). All subjects maintained their remission over a 2-month follow-up. Fluoxetine treatment may be effective in treating major depression in HIV-seropositive asymptomatic patients.

Adult↗

[Role of invasive technics in the occurrence of nosocomial infections. At an intensive care unit].

A prospective study was carried out in a polyvalent medical intensive care unit to determine the role played by diagnostic and therapeutic invasive techniques in the development of four nosocomial infections. Over a 6-month period, 206 patients admitted for more than 48 hours were studied; all had undergone one or several invasive techniques: 76 patients (37 per cent) developed a total of 117 nosocomial infections including urinary tract infection (41.8 per cent), purulent bronchitis (37.5 per cent) septicaemia (11.6 per cent) and pneumonia (7.6 per cent). The risk factors were: duration of urinary or vascular catheterization, tracheal intubation, tracheotomy and artificial ventilation. Gram-negative bacilli (59 per cent) predominated over Gram-positive cocci (39.6 per cent).

Adolescent↗

[Primary staphylococcal septicemia in adults. A retrospective study].

In this retrospective study, 100 cases of primary staphylococcal septicaemia collected in 5 hospitals over a 2-year period were reviewed. Out of 91 strains of Staphylococcus aureus isolated, 6 were methicillin-resistant, but all 6 came from the same hospital. The mortality rate was 36 per cent. The only prognostic factors elicited were chronic renal failure and septic shock. The 64 patients who survived stayed in hospital for a mean period of 42 days, and 42 recovered without sequelae. Staphylococcal infections remain serious and are not all hospital-acquired.

Adolescent↗

Pharmacokinetics of fosfomycin in normal and burn patients. Effect of probenecid.

The pharmacokinetics of fosfomycin are modified in burn patients, suggesting a net tubular secretion in such patients. In an attempt to verify this hypothesis, five healthy normal volunteers were studied The pharmacokinetics of fosfomycin were studied with and without probenecid. In the absence of probenecid, the renal clearance of the drug was equal to that of creatinine. With probenecid, the renal clearance of fosfomycin decreased, whereas creatinine clearance did not. This result suggests the existence of a tubular secretion, which might be enhanced in burn patients.

Adult↗

[Ceftazidime and probabilistic treatment of severe infections in adults].

Probability antibiotic treatments are based on two "best guesses": the nature of the responsible organism and its resistance phenotype. Such treatments are justified in immunocompetent patients with severe infection. The microbiological and pharmacokinetic properties of third generation cephalosporins, and notably ceftazidime, are such that their use as single or combined therapy can be determined. A very wide spectrum and a tendency towards a stronger bactericidal effect are in favour of monotherapy preceded by a short course of bitherapy, especially in cases of hospital-acquired infections.

Adult↗

[Production and application of monoclonal antibodies].

The following article describes both theoretical basis and detailed method for producing monoclonal antibodies in the systems of mouse and man. It further outlines methods to characterize monoclonal antibodies and produce them on a larger scale. Finally, reference is made to their application in research and medicine, and further developments are indicated.

Animals↗