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N Obedeanu

Publications and source records attributed to N Obedeanu.

17 recordsLinked to original sources
PubMed1991

Urinary excretion of Tamm-Horsfall protein in elderly women.

The incidence of urinary tract infection is higher in the geriatric population than in younger adults despite the exclusion of patients with known risk factors. Tamm-Horsfall protein, a renal glycoprotein excreted in urine, may constitute a natural defense mechanism against ascending urinary tract infection by binding mannose-sensitive fimbriated microorganisms. We hypothesized that the quantity of Tamm-Horsfall protein excreted is decreased in the elderly. Native aggregated Tamm-Horsfall protein was measured in urine samples from 24 young women (group 1, mean age 33 years) and 47 female nursing home patients (group 2, mean age 84 years) using enzyme-linked immunosorbent assay techniques. Another 16 elderly women (group 3, mean age 85 years) had active urinary tract infection. The aggregated Tamm-Horsfall protein was then disaggregated by dilution and quantified. Significant differences in mean urinary disaggregated Tamm-Horsfall protein concentrations were found between groups 1 (64.22 mg./l.) and 2 (35.07 mg./l.), and between groups 1 and 3 (34.71 mg./l.), respectively. In contrast, mean aggregated Tamm-Horsfall protein levels were significantly higher in group 2 (1.56 mg./l.) than in group 1 (0.92 mg./l.) or group 3 (0.97 mg./l.). Our studies show that urinary disaggregated Tamm-Horsfall protein concentration is decreased in the elderly, and that aggregated Tamm-Horsfall protein is increased compared to younger adults. The aggregated Tamm-Horsfall protein concentration is decreased in the elderly during episodes of urinary tract infection.

Adolescent↗
PubMed1991

Effect of Tamm-Horsfall protein on chemoluminescence response of polymorphonuclear leukocytes to uropathogenic Escherichia coli.

Mannose residues on the outer membranes of polymorphonuclear leukocytes (PMNL) are capable of binding mannose-sensitive Escherichia coli. Tamm-Horsfall protein, a major urinary glycoprotein, has also been shown to bind mannose-sensitive E. coli via mannose-containing side chains. The effect of Tamm-Horsfall protein on the interaction between PMNL and mannose-sensitive E. coli was studied by measuring luminol-dependent chemoluminescence after bacterial stimulation. In the presence of 0.475, 4.75, 47.5, and 475 mg/l Tamm-Horsfall protein, chemoluminescence responses were reduced in a dose-dependent fashion by 8.7%, 38.1%, 60.3%, and 96.1%, respectively. Addition of 0.003 units/ml alpha-mannosidase reversed the effect of increasing concentrations significantly. Thus, urinary Tamm-Horsfall protein seems to compete with PMNL for mannose-sensitive E. coli in a mannose-sensitive fashion, thereby significantly reducing the role of PMNL as a defense mechanism in the urine of patients with urinary tract infection.

Escherichia coli↗
PubMed1991

Effect of urine and urine components on the chemiluminescent response of bacteria-stimulated polymorphonuclear leukocytes.

The role of polymorphonuclear leukocytes (PMN) found in urine during infectious episodes is still unknown. Opsonophagocytosis of Escherichia coli by normal blood PMN in the presence of urine was measured using a chemiluminescence (CL) assay. PMN were challenged by a type I fimbriated E. coli strain shown to elicit a CL response through attachment to the mannose-containing receptors on the leukocytes. In the presence of urine the CL response decreased significantly. Urine osmolality due to inorganic salts partially caused this decrease. A higher inhibitory effect was elicited by urea. Under otherwise similar conditions, the presence of an additional CL-inhibiting factor, most probably a protein, was detected in urine; however, its identity has not yet been defined. In vitro and in vivo urine dilution improved PMN function. No difference in effect on CL response was found between urine obtained from 25 children with recurrent urinary tract infections and urine from 15 age-matched controls.

Adolescent↗
PubMed1990

Urinary excretion of Tamm-Horsfall protein in women with recurrent urinary tract infections.

Since MS-fimbriated bacteria adhere to Tamm-Horsfall protein, it has been suggested that Tamm-Horsfall protein may trap urinary pathogens and prevent them from colonizing the mucosal surfaces of the urinary tract. To test the hypothesis that low urinary Tamm-Horsfall protein excretion rates predispose to urinary tract infection we obtained serial urine samples from 17 women with and 18 without a history of recurrent urinary tract infection. None of the women had known structural abnormalities of the urinary tract. Concentrations of Tamm-Horsfall protein in urine were measured with a sensitive enzyme-linked immunosorbent assay method. On the average, 3 urine samples per person collected within 3 to 6 months were analyzed. The mean Tamm-Horsfall protein excretion of women with recurrent urinary tract infection was 57.0 mg./l. and that of controls was 66.3 mg./l.; this difference was not statistically significant. The mean coefficient of variation was 44.2 and 62.1%, respectively. We conclude that urinary Tamm-Horsfall protein concentration is not significantly decreased in women with recurrent urinary tract infection compared with controls, and that excretion varies widely in repeat samples obtained from the same individual.

Adult↗
PubMed1990

Quantitation of Tamm-Horsfall protein binding to uropathogenic Escherichia coli and lectins.

In quantitative experiments using ELISA, binding of Tamm-Horsfall protein (THP) to uropathogenic Escherichia coli was studied with monoclonal antibody to THP. Adherence to E. coli bearing type 1 fimbriae was proportional to THP concentration and size of the bacterial inoculum. Type 1 fimbriae-bearing E. coli bound 50 times more THP than did non-type 1-fimbriated or P-fimbriated strains. Concanavalin A and wheat germ agglutinin bound THP in a dose-dependent fashion, whereas pokeweed mitogen and Vicia villosa B4 isolectin did not. Addition of mannose and N-acetylglucosamine reduced adherence of THP to concanavalin A and wheat germ agglutinin by 50%-80%. Sugar inhibition studies suggested that the fimbrial receptor site for THP has lectin-like properties and that THP binds to fimbriae via its mannose side chains. This quantitative assay is useful for studying the interaction between THP, uroepithelial cells, and bacteria in vitro.

Agglutination Tests↗
PubMed1990

Effect of an intravenous gammaglobulin preparation on the opsonophagocytic activity of preterm serum against coagulase-negative staphylococci.

Recent reports have described cases of septicaemia caused by coagulase-negative staphylococci in preterm neonates, mainly due to the use of artificial intravenous devices. It was of interest to examine if intravenous immunoglobulin therapy, known to be effective in group B streptococcal infections of neonates, had a similar beneficial effect in coagulase-negative staphylococcal infections. Opsonophagocytosis of coagulase-negative staphylococci by normal polymorphonuclear leukocytes in the presence of cord blood serum supplemented with the commercial IgG preparation 'Sandoglobulin' was investigated, using luminol-dependent chemiluminescence. It was found that with two different coagulase-negative staphylococcal strains, Sandoglobulin had a concentration-dependent enhancing effect on the chemiluminescent response. This effect was demonstrated in the presence of native as well as inactivated cord blood serum and in the presence of sera from preterm infants (28-33 weeks). It is concluded that intravenous Sandoglobulin therapy may be effective in the treatment of preterm infants with severe coagulase-negative staphylococcal infections.

Drug Evaluation↗
PubMed1990

Saethre-Chotzen syndrome associated with defective neutrophil chemotaxis.

An 11-month-old male infant with Saethre-Chotzen syndrome and recurrent respiratory infections is described. Persistent extremely high leukocytosis warranted evaluation of neutrophil functions. It was found that the opsonophagocytic activity was normal, but neutrophil chemotaxis was markedly decreased. Further studies pointed to an intracellular neutrophil defect causing this motility dysfunction.

Acrocephalosyndactylia↗
PubMed1989

A new ELISA method for the rapid quantification of Tamm-Horsfall protein in urine.

The authors present a simplified enzyme-linked immunosorbent assay (ELISA) technique for the quantitative measurement of urinary Tamm-Horsfall protein (THP). Microtiter plates are coated with THP and urine samples at various dilutions without the need for a capture antibody. The bound glycoprotein is then incubated with a monoclonal anti-THP antibody and an alkaline phosphatase conjugated anti-IgG antibody. The assay was validated and gave reproducible results over a wide range of absorbance values. The sensitivity of the assay for THP was 2-5 micrograms/L, the coefficient of variation between assays 7.5%, and the day-to-day variability 11.1% for THP concentrations between 6.25 and 200 micrograms/L. THP excretion was assayed in five volunteers over five days comparing THP concentration in spot urines and in 24-hour urine collections.

Adult↗
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↗
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↗
PubMed1978

Comparative study of the endotoxin-stimulated nitroblue tetrazolium test in disease and health.

Endotoxin-stimulated nitroblue tetrazolium (NBT) reduction was evaluated in 853 individuals: 270 healthy controls, 334 with various non-neoplastic conditions, 220 with solid non-lymphomatous tumours, and 29 with lymphoma. Each of the above groups was divided into three age subgroups: less than 60, 60-69, and greater than or equal to 70 years. In the controls and in patients with nonmalignant diseases, significantly lower values were recorded for elderly subjects (greater than or equal to 60 years) compared with younger subjects of the same group, whereas in cancer patients the results were independent of age. Under the age of 60, stimulated values for both patient groups were significantly lower than the control values, and in patients with solid non-lymphomatous tumours significantly lower values were attained than in the other patients. NBT reduction in lymphoma patients was comparable to that of the controls. In the elderly (age greater than or equal to 70) no significant differences were noted between patients and controls. It is suggested that stimulated NBT reduction declines with advancing age. While this test clearly demonstrates some leucocyte dysfunction in solid cancer, its value in investigating neutrophil behaviour in elderly subjects is questioned.

Adult↗
PubMed1977

Neutrophil function in cured cancer patients.

Spontaneous and endotoxin-stimulated nitroblue tetrazolium (NBT) dye reduction was evaluated in 86 individuals cured of various types of solid malignancies and in 55 healthy adults. Oxygen consumption tests, at rest and during phagocytosis, were performed with polymorphonuclear leukocytes of 22 patients and 10 controls, chosen at random. The results revealed an impaired capacity of patients' neutrophils to reduce NBT. The decrease in the stimulated reduction values was more pronounced (p less than 0.0005) than in spontaneous values (p less than 0.01), and was also noticed in patients who had been treated by surgery alone and in those with a disease-free interval of 10 years or more. Oxygen consumption by patients' leukocytes was similar to that of controls. The present results, especially those of the endotoxin-stimulated NBT test, might reflect a neutrophil dysfunction in cured cancer patients. The nature of such an abnormality and its possible clinical implication are still obscure.

Adult↗
PubMed1977

Spontaneous and stimulated nitroblue tetrazolium tests of leukocytes from patients with solid malignant tumors.

Histochemical nitroblue tetrazolium (NBT) reduction tests, spontaneous and endotoxin-stimulated, were performed on samples of blood from 202 adult patients with solid neoplastic tumors and 37 healthy control subjects. The patients were classified according to activity of the disease, chemotherapy, and presence of bacterial infection. The NBT test did not prove helpful in detecting the latter condition in these patients. Low median spontaneous reduction values were recorded for patients with active malignancies, or receiving chemotherapy, compared with controls or cured patients without chemotherapy. Stimulated reduction values were significantly lower for all groups of patients than for controls, although for those apparently cured and untreated, stimulated reduction attained significantly higher values than for the other patients. A leukocyte dysfunction caused by both the underlying disease and its chemotherapy is assumed, and the usefulness of the endotoxin-stimulated NBT reduction test in detecting this dysfunction is stressed.

Adult↗
PubMed1977

Polymorphonuclear leucocyte function in Behçet's disease.

Polymorphonuclear leucocyte function was investigated in 19 patients with active Behçet's disease. Spontaneous free leucocyte migration was found to be significantly reduced, yet after stimulation the leucocyte's chemotactic activity was considerably increase (p less than 0-05) when compared to control leucocytes. Control leucocytes migrated more rapidly when incubated in serum taken from patients with Behçet's disease (p less than 0-005). The enhanced chemotactic activity in Bechçet's disease appears to be due to both serum and intrinsic leucocyte factors. Spontaneous nitroblue tetrazolium reduction was found to be normal, although after stimulation leucocyte nitroblue tetrazolium reduction was lower than in the control group (P less than 0-025), as was leucocyte oxygen utilisation. It is suggested that the hyperreactive cellular inflammatory response that characterises Behçet's disease may be due to increased chemotactic activity and minor alterations in functional metabolic activity of leucocytes.

Adult↗
PubMed1975

Standardisation of the nitroblue-tetrazolium test.

Optimal conditions for the NBT-reduction test have been sought. Increasing heparin concentrations up to 100 units per ml and a delay in performance of the test, especially when blood specimens are kept at room temperature, resulted in higher values for the NBT index, which then sometimes exceeded the upper limit of normal in healthy people and in uninfected patients. The effect of pH, composition of the buffer, and dye concentration was also investigated. Phosphate-buffered saline pH 7-2 containing 0-1% NBT dye, without glucose, gave the most reliable results. In endotoxin-stimulated NBT tests, the following procedure is recommended: incubation of 0-1 ml whole blood with lyophilised endotoxin 20 mug per ml. for 15 min. in a 37 degree C water bath, followed by the standard test with a 0-2% NBT solution. By this technique, the leucocyte reaction to various types of lipopolysaccharides was of the same order of magnitude. Drug therapy having an effect on blood components lowered this reaction, whatever the source of endotoxin used as stimulant. The importance of NBT-reduction tests is discussed. Standard conditions of test performance are strictly requisite if comparable results are to be obtained and if data not corresponding with the apparent clinical and other laboratory findings are to be evaluated correctly. The stimulated NBT test, performed in parallel with the standard test, is useful in the interpretation of abnormal results and in the detection of factors with a temporary or permanent effect on the phagocytic activity of pmn leucocytes.

Agglutination↗