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Biomedical subjects

M J Rybak

Publications and source records attributed to M J Rybak.

At least 127 records · Page 7Linked to original sources
PubMed1983

Zomepirac-related acute renal failure.

A case of acute renal failure in a chronic acetaminophen abuser receiving concurrent zomepirac therapy is reported. Zomepirac may have enhanced the negative effects of acetaminophen on renal medullary blood flow, so that the two drugs together were more likely to cause renal failure than either drug alone.

Acute Kidney Injury↗
PubMed1983

Pharmacologic interventions in resuscitation.

Pharmacologic agents are used to improve conditions that may contribute to the development of cardiac arrest such as dysrhythmias, hypotension, shock, or anoxia. The authors review the clinical application of several specific agents in resuscitation.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Effect of human serum on killing activity of vancomycin and teicoplanin against Staphylococcus aureus.

STUDY OBJECTIVE: To investigate the effects of pooled human serum (PHS) on the killing activity of vancomycin and teicoplanin against two isolates of Staphylococcus aureus from patients treated for endocarditis. DESIGN: An in vitro assessment of antibiotic susceptibility and killing rates. SETTING: An urban university teaching hospital. PATIENTS: Pooled human serum from patients treated for endocarditis. INTERVENTIONS: Two clinical isolates of Staphylococcus aureus were obtained from patients treated for endocarditis. Media consisted of cation-supplemented Mueller-Hinton broth alone and in 1:1 dilutions with PHS, 2-hour heat-inactivated PHS (HI-PHS), ultrafiltrate (UF), and 2-hour heat-inactivated ultrafiltrate (HI-UF). Heat inactivation of PHS and UF was accomplished by treatment at 56 degrees C for 2 hours. MEASUREMENTS AND MAIN RESULTS: Killing curves with vancomycin and teicoplanin were performed using drug concentrations of 45 micrograms/ml and a starting inoculum of approximately 1 x 10(6) colony-forming units (cfu)/ml. Bactericidal rates (-log cfu/ml/hr) were calculated from the slope of the killing curves over 0-12 hours (mean 3-8 replicates). CONCLUSIONS: The killing activity of vancomycin in PHS and HI-PHS against both isolates was significantly greater than all other media tested (p < 0.0001). Ultrafiltrate tended to reverse this enhancement effect. Addition of PHS or UF did not enhance teicoplanin's killing activity against either isolate. Further investigations in our laboratory will determine if the factor is antibiotic class or organism specific.

Blood Bactericidal Activity↗
PubMedDate not supplied

Single dose enoxacin for the treatment of uncomplicated urogenital gonorrhea.

Enoxacin, a new broad spectrum azaquinolone, has demonstrated in-vitro activity against Neisseria gonorrhoeae including penicillinase producing strains. We evaluated the safety and efficacy or oral enoxacin 400 mg versus intramuscular ceftriaxone 250 mg for the treatment of uncomplicated genital N. gonorrhoeae infections. Of the 57 patients enrolled, 48 patients (26 men, 22 women) were culture positive and returned for the follow up visit. Six patients (12.5%) had penicillinase producing strains of N. gonorrhoeae, and eleven patients (23%) had concomitant Chlamydia trachomatis infections. Genital gonorrhea was eradicated in 98% of the patients, with a cure rate of 22/23 (96%) in the enoxacin group and 25/25 (100%) in the ceftriaxone group. There were no consequential side effects noted for either agent. Oral enoxacin is a safe and efficacious alternative for the treatment of uncomplicated N. gonorrhoeae infections.

Ceftriaxone↗
PubMedDate not supplied

Ciprofloxacin.

Ciprofloxacin is a new fluorinated quinolone antibiotic with high activity against a wide spectrum of gram-positive and gram-negative bacteria, including methicillin-resistant Staphylococcus aureus, Enterobacteriaceae, and Pseudomonas aeruginosa. Clinical trials using the oral preparation of ciprofloxacin have demonstrated its effectiveness in a wide variety of infections. In addition, extensive clinical trials with the intravenous preparation are underway. In vitro and in vivo studies with ciprofloxacin have reported the incidence of resistant organisms to be very low. In addition, the incidence of ciprofloxacin-related side effects throughout its clinical trials has been minimal. Most reports of side effects have been related to the gastrointestinal tract, such as nausea or vomiting. The incidence of adverse experiences in worldwide clinical trials has been reported to be approximately 6.4 percent.

Bacteria↗
PubMedDate not supplied

Coagulase-negative staphylococci: incidence, pathogenicity, and treatment in the 1990s.

Coagulase-negative staphylococci (CNS), which historically have been viewed as contaminants when recovered in culture media, are now recognized as opportunistic pathogens of increasing importance in hospital-acquired infections. They are frequently found colonizing prosthetic devices and intravenous lines. CNS are capable of producing a variety of infections including deep-seated infections such as endocarditis and meningitis. Staphylococcus epidermidis is the most commonly isolated CNS and it appears to be the most resistant to antibiotics, making antimicrobial therapy challenging. Treatment of the infection will very often require removal of a prosthetic device, if present. An adequate infection control program is imperative in prophylaxis against this infection.

Coagulase↗
PubMedDate not supplied

Vancomycin protein binding in patients with infections caused by Staphylococcus aureus.

The protein binding of vancomycin has been reported to range from less than 10 percent to 82 percent. We examined the binding of vancomycin in 34 patients (14 intravenous drug abusers, 10 burn patients, and 10 control patients) with Staphylococcus aureus infections. Blood samples were collected serially over an 8- or 12-hour dosing interval following a one-hour infusion. In vitro studies were also performed using albumin solutions of varying concentrations. Binding characteristics were determined through ultrafiltration with vancomycin concentrations analyzed for fluorescence polarization immunoassay. The unbound fraction of vancomycin ranged from 0.41 to 0.77 with a mean of 0.54 +/- 0.08. Unbound fractions was significantly correlated with serum albumin concentration (r = -0.344, p less than 0.046) and renal clearance (r = 0.394, p less than 0.021) but not with total body clearance or volume of distribution. In vitro data also showed an association between albumin concentration and unbound fraction (r = -0.94, p less than 0.017). Although vancomycin protein binding changes with serum albumin, this finding may have limited clinical significance.

Adult↗
PubMedDate not supplied

Evaluation of the vancomycin-clearance:creatinine-clearance relationship for predicting vancomycin dosage.

Four methods of predicting vancomycin maintenance doses on the basis of the relationship between total-body or renal clearance of the drug and creatinine clearance were evaluated retrospectively using data from 24 patients who received vancomycin hydrochloride. Data for 18 men and 6 women with creatinine clearances of 10-130 mL/min were used; the mean (+/- S.D.) vancomycin maintenance dose was 22.0 +/- 11.2 mg/kg/day. The actual vancomycin maintenance dose needed to sustain an average steady-state vancomycin concentration of 15 mg/L was determined based on individual pharmacokinetic values. Predicted vancomycin maintenance doses were generated using the vancomycin-clearance:creatinine-clearance relationships derived separately by Nielsen, Moellering, Rotschafer, and Matzke. Orthogonal regression analysis was used to determine relationships between actual and predicted maintenance doses. Predictive ability of each method was assessed for bias (mean error) and precision (root mean squared error). Mean error and root mean squared error (+/- S.D.), respectively, for the four methods were as follows: Nielsen -262 +/- 451, 522 +/- 718; Moellering -91 +/- 439, 448 +/- 547; Rotschafer 192 +/- 602, 632 +/- 682; and Matzke -76 +/- 101, 408 +/- 517. Doses predicted by the Nielsen relationship were significantly lower than the actual vancomycin maintenance doses. Use of the Rotschafer relationship resulted in substantial overprediction, which increased as creatinine clearance declined. Doses predicted by the Moellering and Matzke relationships were slightly less than but not significantly different from the actual dose. The Matzke method demonstrated the least bias and was the most precise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗