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Biomedical subjects

D Merzbach

Publications and source records attributed to D Merzbach.

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

Neopterin measured in serum and tissue culture supernates by a competitive enzyme-linked immunosorbant assay.

In this solid-phase competitive enzyme-linked immunosorbant assay for neopterin (a product of activated macrophages) in serum or supernates of cell cultures, we incubate antiserum to neopterin with standards or samples in the presence of solid-phase-bound conjugate of carrier-neopterin. Incubation with second antibody labeled with peroxidase then follows, before reaction with substrate. Analytical recovery, precision, and sensitivity of this method are similar to those of other immunoassays. The assay range is between 0.4 and 100 micrograms of neopterin per liter. Results obtained by this method compared with those from a conventional radioimmunoassay gave a correlation coefficient of 0.974.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Waterborne typhoid fever in Haifa, Israel: clinical, microbiologic, and therapeutic aspects of a major outbreak.

A major outbreak of waterborne typhoid fever involving 77 verified cases occurred in 1985 in a large suburban area of Haifa, Israel. The authors summarize the clinical, microbiologic, and therapeutic aspects of these patients. Fever, usually higher than 39 degrees C, was the hallmark of the disease. Other manifestations of typhoid, although relatively frequent, are presented as part of a mild nonspecific symptom complex, often found only in the prodromal period. An elevated level of serum glutamic-oxaloacetic transaminase (mean, 81 IU/ml) was the most characteristic laboratory abnormality, occurring in 94% of the patients. Blood cultures were positive in 46 of the 50 patients (92%), and were not affected by prior outpatient antibiotic therapy. The first blood culture was diagnostic in 93% of the cases. Although fever tended to disappear more rapidly among patients receiving ampicillin than among those treated with chloramphenicol, results of therapy were similar in both groups. Nevertheless, the relapse rate of 36% among 25 chloramphenicol-treated patients was significantly higher than the 9% noted among 22 patients treated with ampicillin. Except for one case of hemolytic anemia, serious complications were conspicuously absent, and outcomes were uniformly favorable.

Adolescent↗
PubMed1988

Chemiluminescence response of polymorphonuclear leucocytes to serum-opsonized zymosan--a predictive parameter for infections and prognosis in multiple myeloma patients.

Serum opsonization capability and phagocytosis by polymorphonuclear leucocytes (PMNL) were investigated in 37 patients with multiple myeloma (MM), 32 patients with chronic lymphocytic leukaemia (CLL), and 30 healthy controls. Opsonophagocytosis was assessed by measuring the chemiluminescence (CL) response of controls' and patients' PMNL to control- and patient-serum-opsonized zymosan particles. Control PMNL CL responses were significantly reduced both by MM and CLL sera. Normal sera restored the CL responses in MM patients, but only partially corrected the CL responses in CLL patients. Significant correlations were found between the CL responses in MM patients and four clinical parameters: clinical stage, presence of disease-related symptoms, incidence of bacterial infections, and outcome. The findings suggest a defect in MM and CLL sera opsonization ability which, at least in part, could account for the increased susceptibility to infections observed in these patients. Furthermore, the assessment of the CL response in MM patients is recommended as a simple and useful clinical tool for prediction of susceptibility to infection, and prognosis.

Acridines↗
PubMed1987

Single-dose antimicrobial therapy in the treatment of asymptomatic bacteriuria in pregnancy.

Fifty obstetric patients with asymptomatic bacteriuria were treated by single-dose antimicrobial therapy. The immediate cure rate was 84% and the recurrence rate was 12%. Seven of the eight patients in whom single-dose treatment failed responded to subsequent 7-day therapy with the same drug, indicating renal involvement. A 50% recurrence rate in the group of patients in whom single-dose treatment failed was compared with a 5% recurrence rate in the group cured by single-dose therapy, which indicates that failure with single-dose antimicrobial therapy can serve as a therapeutic test to identify patients at high risk for recurrent bacteriuria and its sequelae during pregnancy. It is concluded that single-dose antimicrobial therapy is a safe and effective way to treat asymptomatic bacteriuria in pregnant patients without urologic problems in their history.

Amoxicillin↗
PubMed1987

Five-year survey of changing patterns of susceptibility of bacterial uropathogens to trimethoprim-sulfamethoxazole and other antimicrobial agents.

We analyzed the antibiotic susceptibility of 5,348 urinary isolates of Escherichia coli, "Klebsiella aerogenes," and Proteus mirabilis grown in three laboratories from 1980 to 1985. A continuous rise in resistance to trimethoprim-sulfamethoxazole was observed; 63% of the strains from inpatients in 1984 and 51% of those from outpatients in 1985 were resistant to this drug. Isolates from outpatients in 1985 were mostly susceptible to nitrofurantoin (mean susceptibility, 92%) and to oral cephalosporins (mean susceptibility, 84%). As for isolates from inpatients, none of the antimicrobial agents now used was satisfactory for initial chemotherapy, indicating a need for new antibacterial strategies.

Ampicillin↗
PubMed1986

Escherichia coli adherence to human transitional cell tumors: a simple research model of bacterial attachment to the lower urinary tract.

A simple model for assaying bacterial adherence to the urinary tract is presented. Cell suspensions of freshly excised transitional cell tumors were used as substrata for attachment of 3H-adenine-labeled Escherichia coli urine isolates. Quantitative radioactive counts were confirmed by microscopic observations in replicate assays of each condition tested. This model provided for species and organ specificity in studies of the bacterial adherence role in urinary tract infections.

Bacterial Adhesion↗
PubMed1985

Recurrent intraabdominal abscess caused by Salmonella paratyphi C.

We describe a patient who suffered from recurrent intraabdominal abscesses. The last two of the three abscesses were certainly caused by Salmonella paratyphi C. The time interval between the first and the second abscess was 25 years, and that between the second and the third abscess was 20 years. Single infection with this microorganism is very rare in Israel, with only four known cases in the last 20 years. The annual frequency in the United States is 0 to 2 cases per year. In recent years, this infection has also been very rare in other parts of the world. Our case is unique as it recurred two or three times. The infection was probably dormant for a very long time. During the dormant years, the patient was clinically healthy. To our knowledge a recurrent infection with this microorganism has not previously been reported in the literature.

Abdomen↗
PubMed1984

Phagocytosis of mucoid and nonmucoid strains of Pseudomonas aeruginosa.

In order to evaluate the role of mucoid coating of clinical isolates of Pseudomonas aeruginosa as a virulence factor, opsonophagocytosis of mucoid and nonmucoid strains of P. aeruginosa were studied by three different methods: uptake of [3H]adenine-labeled bacteria, oxygen consumption, and chemiluminescence production by phagocytosing polymorphonuclear leukocytes. All three methods showed a strong correlation with regard to phagocytosis of the bacterial isolates. As a group, the mucoid strains of P. aeruginosa demonstrated significantly reduced phagocytic uptake by leukocytes when compared to nonmucoid strains, although occasionally mucoid strains did exhibit normal uptake. In vitro growth of mucoid strains under nonstationary conditions was associated with reduced mucoid coating and with a corresponding increase in susceptibility to leukocyte phagocytosis. Although the overall bactericidal activity of human polymorphonuclear leukocytes for mucoid strains was diminished, this appears to be a function of reduced ingestion since the rate of intracellular killing was similar for mucoid and nonmucoid strains. The enhanced susceptibility of mucoid strains to spontaneous bactericidal activity of pooled human serum was confirmed. Mucoid-producing strains produced less protease in vitro; however, the role of this phenomenon in influencing phagocytosis is unknown.

Blood Bactericidal Activity↗
PubMed1984

Serum IgG antibodies to gliadin in children with celiac disease as measured by an immunofluorescence method.

Antigliadin antibodies (AGAs) were studied in sera from 190 patients divided into five clinical groups. Group I included 28 sera from children with newly diagnosed celiac disease on a normal diet. Group II consisted of 43 sera from children with celiac disease who were fed a gluten-free diet (GFD). Group III included 25 sera from children with celiac disease who had been in remission but exposed to a gluten-containing diet (GCD). Group IV consisted of 46 sera from children with chronic diarrheal disorders other than celiac disease. Group V included 43 sera from healthy children. The observed p values proved that (a) mean titer levels of AGAs in Groups I and III were significantly higher than the mean values for all other groups (p less than 0.001), and (b) the mean titer level of AGAs in Group II was significantly higher than the mean values for Groups IV and V. A good correlation between the AGA titers and the morphology of the duodenal mucosa was found in children with celiac disease. The examination of IgG AGAs by the immunofluorescence technique used in our study appears to be a useful tool in the follow-up of individual patients to determine adherence to a GFD.

Animals↗
PubMed1984

Elucidation of the phagocytosis mechanism with the aid of luminous bacteria.

Phagocytosis of the luminous bacterium Vibrio cholerae var. albensis caused a similar decrease both in viable count and in the in-vivo luminescence. These effects of polymorphonuclear neutrophil leukocytes (PMN) were oxygen-dependent processes. Exposure of PMN to oxygen caused a prompt decrease in the luminescence of bacteria that had been ingested in anaerobic conditions. Cell-free supernates from active PMN suspensions caused a decrease in luminescence and as much as 10% of the killing could be attributed to extracellular killing. Similarly, bacteria entrapped on a membrane filter showed a decrease in luminescence upon addition of active PMN, even though they could not be ingested.

Aerobiosis↗
PubMed1984

Staphylococcus aureus bacteremia and endocarditis: comparison of nosocomial and community-acquired infection.

Staphylococcus aureus bacteremia continues to be a frequent clinical problem even in communities where intravenous drug abuse is relatively rare. One-hundred-three evaluable cases of S. aureus bacteremia that occurred in a large tertiary care facility over a four year period (1979-1982) are reviewed. A comparison of nosocomial and community-acquired S. aureus bacteremia reveals several fundamental differences. Community-acquired S. aureus bacteremia frequently develops in the absence of a primary focus of infection and is more likely to result in endocarditis and secondary metastatic foci of clinical infection. In contrast, nosocomial S. aureus bacteremia tends to be diagnosed earlier, a primary site of portal entry is usually identified and endocarditis is less frequent as are secondary foci of infection. Irrespective of the epidemiological origin of S. aureus bacteremia, the mortality remains high particularly in nosocomial infection where the presence of severe underlying disease contributes to the high mortality. Methicillin resistant S. aureus adds a new dimension to the challenge of successful treatment of staphylococcal bacteremia.

Adolescent↗
PubMed1983

The use of luminous bacteria for determination of phagocytosis.

The existing methods for phagocytosis evaluation are inadequate for assessing all the real events occurring during phagocytosis, or for continuously following the kinetics of the process. Our purpose is to establish the use of luminous bacteria as an object for phagocytosis. The bioluminescence test offers an easy and simple method to determine the kinetics of phagocytosis by following the luminescence of the bacteria. The terrestrial luminous bacteria Vibrio cholerae var. albensis are readily phagocytosed by polymorphonuclear (PMN) cells. The correlation coefficient between the decrease in luminescence and the decrease in viable count is 0.999. The rate of decrease in luminescence and the residual level of luminescence after 60 min of phagocytosis are proportional to the rate of increase in phagocytosis induced chemiluminescence, and to its maximal level, respectively. Opsonization requirements are comparable in both tests. Different inhibitors of the phagocytosis process caused similar changes in the rates of the bio- and chemiluminescence (correlation coefficient 0.974), and in the luminescence maximal level (correlation coefficient 0.804). The validity of the bioluminescence assay being proved, it is suggested as an alternative assay for phagocytosis assessment.

Azides↗
PubMed1983

Phagocytosis-induced mutagenesis in bacteria.

Dark mutants of the luminous bacteria Photobacterium fischeri reverted to hereditary stable luminescent forms when incubated with human polymorphonuclear neutrophils (PMN). The maximal mutagenic effect occurred during the first 15 min of phagocytosis, and was dependent on the phagocyte:bacterium ratio as well as on the integrity of the PMN cells. Heat-killed phagocytes or disintegrated phagocytes did not show any mutagenic activity, whereas the supernatant of the phagocytosis reaction exerted mutagenic activity. Scavengers of hydroxyl radical such as mannitol or benzoate and scavengers of singlet oxygen such as beta-carotene, as well as the presence of superoxide dismutase, prevented the mutations. The role of reactive oxygen metabolites in the phagocyte-mediated mutagenic process is discussed.

Anaerobiosis↗
PubMed1983

Determination of serum bactericidal activity with the aid of luminous bacteria.

Nonmarine luminous bacteria belonging to the genus Vibrio cholerae were extremely sensitive to the bactericidal activity of human serum. Luminous bacteria incubated in a medium containing serum showed a decrease in their in vivo luminescence that was directly proportional to the decrease in the viable count and was a function of the serum concentration. Both immunoglobulins and the complement system were required to exert the serum bactericidal activity. Serum lacking immunoglobulins or certain complement components, especially C3, did not affect the luminescence. The bactericidal effect of the serum on luminous bacteria was diminished by the presence of lipopolysaccharide or by pretreatment of the serum with different species of killed bacteria. As found in other systems, the bacteriolytic activity of serum was only augmented by lysozyme, but was not lysozyme dependent; although the luminous bacteria were converted into spheroplasts in serum containing 0.5 M sucrose, their in vivo luminescence was almost not affected. This system could easily distinguish between the C classical pathway and the properdin pathway. Ethylene glycol-bis (beta-aminoethyl ether)-N,N'-tetraacetic acid, which inhibits only the classical complement pathway, did not inhibit the decrease in luminescence as did EDTA. Thus, it was possible to distinguish between deficiencies in complement components participating in both pathways and complement components that were involved only in the classical pathway. This system could also be used as a substitute to the hemolytic system in complement fixation tests.

Animals↗