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Biomedical subjects

E Toma

Publications and source records attributed to E Toma.

At least 19 recordsLinked to original sources

Inducible beta-lactamases in clinical isolates of non-aeruginosa Pseudomonas.

The incidence of antimicrobial resistance and expression of imipenem-inducible beta-lactamase were examined in 22 strains of non-aeruginosa Pseudomonas isolated from clinical specimens. The percentage of strains resistant to form one to eight antibiotics was 45. The most active antibiotics against all strains were norfloxacin, ciprofloxacin and imipenem. Eighteen out of the 22 strains were positive for beta-lactamase in a spectrophotometric assay using nitrocefin as substrate. A low inducible beta-lactamase specific activity (0.001-0.999 nmoles nitrocefin hydrolyzed/min/mg protein) was found in twelve strains whereas six strains had a relatively high specific activity (3.5-159.8 nmoles nitrocefin hydrolyzed/min/mg protein). Five strains representing different Pseudomonas spp. and showing high beta-lactamase activity were studied further. Crude enzymes from two species (Pseudomonas mendocina, Pseudomonas acidovorans) hydrolyzed cefazolin at a higher rate than penicillin and ampicillin. All enzymes from the five species were inhibited by cloxacillin and p-chloromercuribenzoate (1 mM), but were insensitive to inhibition by clavulanic acid, ethylenediamine acetic acid (EDTA) at the same concentration. The isoelectric point and molecular weight of the main beta-lactamase band from the 5 species were 6.5-6.8 and 47,000 respectively.

Cefazolin

Immunologic thrombocytopenia followed by thrombotic thrombocytopenic purpura in two HIV1 patients.

Two homosexual HIV1-positive male patients with thrombotic thrombopenic purpura (TTP) were found to have past history of immune thrombocytopenia (ITP). The first patient had ITP 10 months prior to TTP and was successfully treated by splenectomy. The second patient had ITP 32 months before TTP. No specific treatment was given for his asymptomatic ITP. Association of HIV infection to TTP seems to be frequent. These two types of purpura have different pathogenic mechanisms but share a common altered immune response to antigenic challenge. The occurrence of ITP and TTP in HIV-positive patients may lead to errors in diagnosis and therapy.

Adult

Clindamycin/primaquine for treatment of Pneumocystis carinii pneumonia in AIDS.

In an open clinical trial, 109 episodes of Pneumocystis carinii pneumonia (70 proven and 39 highly probable) were treated with clindamycin/primaquine. These episodes were in 35 patients who failed on standard therapy and 15 who did not tolerate standard therapy; 59 patients received this regimen as their initial treatment. The clinical outcome was excellent with only 8 cases of failures encountered (6 patients also failed on standard therapy). The onset of clinical response was obvious in less than 72 hours in 81% of patients; the relapse rate was very low. The regimen was well tolerated and compares advantageously with conventional therapy for Pneumocystis carinii pneumonia.

Acquired Immunodeficiency Syndrome

Clindamycin with primaquine for Pneumocystis carinii pneumonia.

Combined therapy with clindamycin and primaquine was used in twenty-eight episodes of Pneumocystis carinii pneumonia in 25 patients, of whom 17 had been unresponsive or intolerant to conventional treatment and 8 were being treated for the first time. The treatment was effective in all but two episodes, the main adverse reaction being a generalised maculopapular rash.

Administration, Oral

Structure--activity relationship of quinolones.

The understanding of some structure-activity relationships of quinolones allowed the development of the new fluorinated quinolones, compounds with a major clinical potential. The basic structure of these drugs consists of a substituted pyridine ring and a carboxylic acid ring. The substitution at the first position is vital for antibacterial activity, while the presence of a fluorine atom and a piperazine ring is responsible for a broader spectrum of activity and higher intrinsic potency. Further modifications at side-chains or on the ring structure provide compounds with different pharmacokinetic or/and antibacterial activity. A better understanding of these relationships and correlations with clinical results is essential for the design of new improved derivatives with therapeutic potential.

Chemical Phenomena

Amoxycillin for parenteral use: a pharmacological and clinical evaluation.

Pharmacological studies with intramuscular amoxycillin and intramuscular ampicillin were carried out in ten patients. Serum, urine levels, urinary recovery and renal clearance of intramuscular amoxycillin were similar to intramuscular ampicillin and to oral amoxycillin. The time to peak serum concentration was later for amoxycillin. Sputum levels were higher for amoxycillin. Amoxycillin intramuscularly was more painful than ampicillin in eleven out of thirty patients. The clinical response, evaluated in twenty-five patients was good and similar to ampicillin in our experience.

Administration, Oral

Cephacetrile, a new cephalosporin: in vitro, pharmacological and clinical evaluation.

Cephacetrile, a parenteral cephalosporin, was evaluated for in vitro antibacterial activity, clinical pharmacology and effectiveness in the treatment of severe infections. The antibacterial activity against 187 isolates was determined by an agar-dilution technique. The MICs were 0.06 to 0.5 mug/ml for Group A Streptococcus, D. pneumoniae, and Staph. aureus, 4-6 mug/ml for E. coli and Klebsiella-Enterobacter 8-32 mug/ml for Pr. mirabilis and more than 500 mug/ml for Ps. aeruginosa. A few strains of Klebsiella and E. coli had MICs of more than 125 mcg/ml. Serum levels after 0.5 and 1 g of i.m. cephacetrile were respectively 14.6 and 18.6 mug/ml after 1 hr, and 1.5 and 2.5 mug/ml after 6 hr. Serum levels after i.v. infusion of 0.5 and 1 g were respectively 16 and 25 mug/ml after 1 hr., and 1 and 2 mug/ml after 6 hr. Urine levels after 0.5 and 1 g i.m. cephacetrile were respectively 500 and 650 mug/ml in the 0-3 hr period, and 250 and 300 mug/ml in the 3-6 hr period. Renal clearance was 166 +/- 5 ml/min/1.73 m2; renal excretion was about 20% of the dose 6 hr after i.m. injection. Cephacetrile was well tolerated when administered i.m. with lidocaine. Mild phlebitis occurred sometimes after i.v. infusions. The clinical response, evaluated in 36 patients with severe systemic, respiratory and urinary infections, was good in all but two cases.

Bacteria

Medium-long incubation posttransfusional hepatitis (a possible immunological implication).

Icteric hepatitis which developed in the first 6 months after blood transfusion was studied in 159 cases. One fourth of these (39) occurred within a period of only 15 days: between the 30th and 45th day after transfusion. So, their incubation period was longer than that of short incubation hepatitis (type A), and shorter than that of long incubation hepatitis (type B). In these cases the incidence of HBs antibodies was more than 10 times greater than in hepatitis with long incubation, and the incidence of HBs antigen was approximately the same as in the healthy control group. This fact suggests the involvement of a special factor in their appearance, probably an immunologic (or of other nature) process giving rise to antigen-antibody complexes in the HB ag-ab system.

Antibodies

Passive hemagglutination and complement fixation reactions in the early diagnosis of Mycoplasma pneumoniae infections.

Complement fixation (CF) and passive hemagglutination (PHA) tests (the latter with a M. pneumoniae antigen coupled by glutaraldehyde onto red blood cells) were performed in 263 patients with various infectious diseases (mostly in the 1st and 2nd week after onset) and non-infectious ones. CF reaction proved to be inappropriate for the early etiological diagnosis of mycoplasma infections, since the high titers were distributed undifferentially among the various patient groups and many sera (38%) showed anticomplementary activity. A PHA titer of at least 1/128 (preferably of 1/512) points to the presence of a M. pneumoniae infection, especially if clinical, radiological and laboratory data suggest a nonbacterial or mixed pneumonia. The diagnosis is often early enough to orientate the etiological therapy towards macrolides and tetracyclines. The PHA reaction recommended is specific, sensitive, reproducible and easy to perform.

Complement Fixation Tests