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Biomedical subjects

R Yogev

Publications and source records attributed to R Yogev.

At least 127 records · Page 7Linked to original sources
PubMed1985

Treatment of pediatric infections with amikacin as first-line aminoglycoside.

Because of increased aminoglycoside resistance of hospital bacterial isolates, aminoglycoside sensitivity patterns of isolates in a large children's hospital were assessed before and during a 33-month period of almost exclusive amikacin use. There was no significant change in overall resistance rates of gram-negative enteric bacteria to gentamicin (4.8 percent and 4.6 percent), tobramycin (2.5 percent and 3.6 percent), and amikacin (1.2 percent and 1.8 percent) from the pre-amikacin period to the amikacin usage period, respectively. No significant differences were observed for isolates of Escherichia coli, Klebsiella, Serratia, Acinetobacter, and Pseudomonas species. In contrast, significant decreases in gentamicin and tobramycin resistance rates for Enterobacter, Citrobacter, and Pseudomonas aeruginosa and in gentamicin resistance of Proteus were found. Very little change in resistance of staphylococcal isolates was seen during a shorter evaluation period. Pediatric aminoglycoside usage includes therapy of neonatal infections, cystic fibrosis, febrile neutropenic episodes in patients with cancer, abdominal surgery, bacterial endocarditis, and gram-negative central nervous system infections. Amikacin has also been used successfully as single-dose therapy of urinary tract infections, and acceptable cerebrospinal fluid levels of amikacin have been documented in hydrocephalic patients with ventriculitis. In vitro studies of 22 bacterial isolates demonstrated synergy between amikacin and penicillin or newer cephalosporins in 13, an additive effect in seven and indifference in two. No antagonism was found. In addition, in vivo synergy between imipenem and amikacin was found in neutropenic infant rats with P. aeruginosa sepsis using a strain with which no synergy was demonstrable in vitro. Amikacin is effective in pediatric infections and is well tolerated by children. Because excessive or inadequate levels are frequent with usually recommended doses, particularly in neonates and patients with compromised renal function or cystic fibrosis, serum levels should be monitored to minimize risk and to ensure therapeutic levels.

Amikacin↗
PubMed1985

Penicillin plus rifampin eradicates pharyngeal carriage of group A streptococci.

We evaluated the efficacy of rifampin in eradicating chronic pharyngeal carriage of group A streptococci. Carriers were defined as healthy children whose throat cultures showed persistence of group A streptococci 3 weeks after receiving benzathine penicillin G intramuscularly. Subsequent M and T typing of group A streptococcal isolates and limited serologic studies confirmed that enrolled patients were carriers. Thirty-eight carriers (37 completed the study) were randomly assigned to three groups: group 1 (13 patients) received no treatment; group 2 (10) received benzathine penicillin intramuscularly; group 3 (14) received benzathine penicillin intramuscularly plus rifampin orally (10 mg/kg twice a day for eight doses). Throat cultures were obtained every 3 weeks for at least 9 weeks. Group 2 and 3 patients who still had positive cultures 3 weeks after treatment were crossed to the opposite group. Cultures became negative in 93% (13 of 14) of patients in group 3, compared with 23% in group 1 and 30% in group 2 (P less than 0.001 and P less than 0.01, respectively). Including patients crossed over, the penicillin plus rifampin regimen was effective in 17 (89%) of 19 treatment courses and was significantly superior to no therapy or to penicillin alone (P less than 0.0005 and P less than 0.005, respectively). We conclude that rifampin plus benzathine penicillin intramuscularly is an effective regimen for those selected patients in whom eradication of group A streptococcal carriage is judged to be desirable.

Administration, Oral↗
PubMed1985

Radioenzymatic assay for trimethoprim in very small serum samples.

A modification of the methotrexate radioassay kit (supplied by New England Enzyme Center) enabled determination of trimethoprim levels in 5-microliter serum samples. An excellent correlation between this assay and high-pressure liquid chromatography assay was found. These preliminary results suggest that with this method rapid determination of trimethoprim levels in very small samples (5 to 10 microliters) can be achieved.

Humans↗
PubMed1985

Rifampin and penicillin for the elimination of group B streptococci in nasally colonized infant rats.

Although multiple antibiotic strategies to eradicate group B streptococci (GBS) from colonized infants and women have been utilized, no regimen has been successful in eliminating GBS carriage reliably. Because rifampin has been successful in terminating nasopharyngeal colonization with other bacteria, we tested both the in vitro sensitivity of GBS to rifampin and the in vivo efficacy of rifampin in eliminating GBS from a new animal model of nasally colonized infant rats. The minimal inhibitory concentration of rifampin for 18 clinically derived strains of type III GBS ranged from 0.1 to 0.4 micrograms/ml. Atraumatic nasal inoculation of infant rats with 10(6)-10(7) colony forming units of GBS twice daily for 4 days resulted in heavy asymptomatic carriage for at least 10 days. Colonized animals were divided into four treatment groups: saline, oral rifampin, intraperitoneal penicillin, or oral rifampin plus intraperitoneal penicillin. Treatment was administered every 12 h for 4 days. All 78 saline-treated controls and 47 of 52 (90.4%) penicillin-treated animals had continued GBS carriage 36 h after completion of therapy. In contrast, only 18 of 52 (34.6%) rifampin-treated animals and seven of 54 (13.0%) rifampin plus penicillin-treated animals remained GBS-positive. No rifampin-resistant GBS were detected. Combination rifampin plus penicillin therapy was significantly more effective in terminating GBS carriage compared to saline or penicillin alone (p less than 0.0001) or to rifampin (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Fatal fulminant hepatitis with hemolysis in Wilson's disease. Criteria for diagnosis.

We report a child with the presentation of Wilson's disease as acute fulminant hepatic failure and severe hemolysis. Our review of the literature suggests the following criteria for considering this diagnosis in the child with acute liver failure: discordance between mildly elevated serum transaminases and extremely elevated bilirubin levels; anemia associated with hemolysis (increased reticulocytes in the absence of bleeding); elevated hepatic copper; and other copper metabolic abnormalities (elevated serum copper, excessive 24-hour urine copper excretion, and reduced serum ceruloplasmin). Establishing the correct diagnosis enhances the possibility of detecting asymptomatic siblings or other family members in whom early inauguration preventive therapy should be successful.

Anemia, Hemolytic↗
PubMed1983

Single-dose ceftriaxone pharmacokinetics in pediatric patients with central nervous system infections.

Ceftriaxone has greater in vitro and in vivo efficacy against many common bacteria than other third-generation cephalosporins. Single-dose ceftriaxone pharmacokinetics were studied in 17 patients, aged 0.6 to 52 months, with infections of the central nervous system. Patients received a randomized dose of 50 or 75 mg/kg ceftriaxone intravenously over 5 minutes on the second to fifth day of illness. Serial blood samples were collected over 24 hours in all patients, and cerebrospinal fluid (CSF) was obtained 1 to 4.5 hours after injection. Ceftriaxone mean peak plasma concentrations, determined by high-power liquid chromatography, were 267 and 184 microgram/ml for the 75 and 50 mg/kg dosage groups, respectively. The harmonic mean elimination half-life was 4.2 hours, and the mean percent drug penetrance into CSF was 4.8 +/- 3.5%. Of CSF studies evaluated, the glucose concentration was correlated most closely (inversely) with CSF penetration of ceftriaxone. Individual CSF concentrations of ceftriaxone exceeded the minimal inhibitory concentrations of the respective bacteria causing infection by 480 to 5,600 times. Ceftriaxone may be useful in the treatment of serious pediatric infections, including meningitis.

Cefotaxime↗
PubMed1983

Single-dose amikacin treatment of first childhood E. coli lower urinary tract infections.

Urinary tract infection in children is usually treated with orally administered antibiotics for 10 to 14 days. Because of the unreliability of patient compliance with prescribed medications and because single-dose aminoglycoside therapy has been shown to be effective in women with cystitis, we assessed the efficacy of single-dose amikacin for treatment of first episodes of Escherichia coli lower urinary tract infection in girls. Upper and lower urinary tract infections were presumptively differentiated by simple criteria such as clinical symptoms, fever, and erythrocyte sedimentation rate. Fifty-four girls (ages 1 to 12 years) with two positive urine cultures (greater than 10(5) CFU/ml E. coli) were assigned by a table of random numbers to receive treatment with either sulfisoxazole 150 mg/kg/day orally for 10 days or a single dose of amikacin 7.5 mg/kg intramuscularly. Six of 23 patients (26%) in the amikacin group and four of 21 (19%) in the sulfisoxazole group had at least one positive urine culture within 40 days after completion of therapy. This difference was not statistically significant (P greater than 0.5). This suggests that a single dose of amikacin is as effective as a 10-day course of sulfisoxazole in the treatment of presumed first lower urinary tract infection in girls. Additional potential advantages of single-dose therapy are fewer side effects and less toxicity, excellent compliance, and reduced potential for selecting resistant organisms.

Amikacin↗
PubMed1983

Ceftriaxone therapy of group B streptococcal bacteraemia and meningitis in infant rats.

The efficacy of ceftriaxone against group B streptococci was studied in vitro and in vivo with an infant rat model of group B streptococci bacteraemia and meningitis. Twenty-four strains demonstrated minimal inhibitory concentrations of ceftriaxone of 0 . 05-0 . 1 mg/l and minimal bactericidal concentrations of 0 . 1-0 . 4 mg/l. Four strains were selected to induce bacteraemia and meningitis in infant rats by intraperitoneal inoculation. All 45 bacteraemic animals with or without meningitis that were treated with ceftriaxone 2 mg/kg/dose every eight hours for five doses survived, while all 12 control animals died (P less than 0 . 001). When recultured 54 h after the last dose of ceftriaxone, both CSF and blood remained sterile in all treated animals. These results indicate group B streptococci to be sensitive to ceftriazone in vitro and that, in the low dosage used, ceftriaxone effectively eradicates group B streptococcal bacteraemia and meningitis in infant rats.

Animals↗
PubMed1983

Comparative in vitro and in vivo activity of temocillin (BRL 17421) and ampicillin against Haemophilus influenzae type b.

A total of 42 strains of Haemophilus influenzae type b isolated from pediatric patients were sensitive in vitro to temocillin (90% minimal inhibitory concentration = 0.25 microgram/ml). No difference in mean minimal inhibitory concentration between beta-lactamase producer (0.25 microgram/ml) and nonproducer (0.23 microgram/ml) strains was found. Various dosages of ampicillin or temocillin for the treatment of infant rats with ampicillin-resistant H. influenzae bacteremia and meningitis yielded no difference in cure rates. These results suggest that temocillin may not be as effective as other new cephalosporins for the treatment of H. influenzae type b infections.

Ampicillin↗
PubMed1983

Fatal hepatitis B in early infancy: the importance of identifying HBsAg-positive pregnant women and providing immunoprophylaxis to their newborns.

Infants born to women who are asymptomatic hepatitis B surface antigen (HBsAg) carriers frequently acquire hepatitis B virus infection in infancy. The spectrum of disease in such affected infants includes mild transient acute hepatitis B, chronic active hepatitis with or without cirrhosis, chronic persistent hepatitis, chronic asymptomatic HBsAg carriage, and, rarely, fulminant fatal hepatitis B. Recently, the administration of hepatitis B immunoglobulin has been demonstrated to reduce the risk of infantile acquisition of hepatitis B virus; hepatitis B vaccine may also be preventive in this setting. Three young infants, aged 8 to 16 weeks, who died of acute fulminant hepatitis were studied. In each instance, the mother was found, retrospectively, to be asymptomatic but HBsAg positive. One of these mothers was hepatitis B e-antigen-negative but hepatitis B e-antibody positive. All three babies were HBsAg positive; two who were tested for hepatitis B core antibody were positive. These three fatalities serve to dramatize both the importance of HBsAg screening of pregnant women, particularly those with demographic factors that place them at increased risk for HBsAg carriage, as well as the significance of effective immunoprophylaxis for hepatitis B in all offspring of women with HBsAg seropositivity.

Carrier State↗