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Biomedical subjects

A Shelokov

Publications and source records attributed to A Shelokov.

At least 19 recordsLinked to original sources
PubMed1980

Adherence of influenza A viruses to group B Streptococci.

Previous studies have revealed a similarity between hemadsorption and bacterial adherence to virus-infected cells. This observation led to the question of whether mature virions can interact directly with bacteria in a manner similar to hemagglutination. Thus, hemagglutination inhibition, direct immunofluorescence, and scanning electron microscopy were used to detect adherence of five prototype strains of influenza A virus to 34 strains (five serologic prototypes and 29 isolates from ill infants) of group B Streptococcus. Group B Streptococcus serotypes Ia, Ic, and III appear to possess receptors for the five influenza strains that are sensitive to receptor-destroying enzyme. The results of adherence tests with Streptococcus serotype Ib depended on which bacterial strain was used. Only one virus prototype, Jap/305/57(H2N2), adhered to all of the 34 strains of Streptococcus tested.

Hemadsorption↗
PubMed1978

Bacterial adherence to virus-infected cells: a cell culture model of bacterial superinfection.

MDCK cells (a line of stable canine kidney cells) infected with influenza A/NWS/33 virus (a neurotropic variant of the Wilson Smith strain) were tested with 18 selected bacterial species to determine whether mammalian cells become susceptible to bacterial adherence as a result of virus infection. Cell monolayers were washed and examined microscopically for adherence. Bacteria of only two of 18 species were seen to adhere to the infected cells: a group B Streptococcus and Streptococcus sanguis. Control monolayers were negative for adherence. Pretreatment of virus-infected cultures with mouse ascitic fluid containing antibody to influenza A virus completely blocked adherence of the bacteria. Further testing with the strains representative of the five serotypes of group B Streptococcus disclosed that adherence occurred with types Ia, Ic, and II, but not with types Ib and III.

Adhesiveness↗
PubMed1978

Immune response in urinary tract infection determined by radioimmunoassay and immunofluorescence: serum antibody levels against infecting bacterium and Enterobacteriaceae common antigen.

A solid-phase radioimmunoassay (RIA) procedure was compared with the indirect fluorescent antibody (IFA) test in a serological study of 76 female adults with urinary tract infections. Relative serum antibody activity was determined against patients' homologous infecting enterobacteria by RIA and IFA and against heterologous enterobacterial common antigen (Escherichia coli O14) by RIA. There was marked correlation between results of the IFA and RIA methods using the homologous system; 22 of 51 patients (43%) with pyelonephritis had significantly elevated serum antibody activity by both IFA (titers greater than or equal to 512) and RIA (binding ratio greater than or equal to 2.0) when compared with normal serum controls; three had significant antibody activity detectable by RIA only. Eighteen (72%) of 25 patients with pyelonephritis had RIA binding ratios of greater than or equal to 2.0 against their homologous bacterial isolates and the enterobacterial common antigen; an additional 6 patients had binding ratios of greater than or equal to 2.0 against the antigen only. All 25 patients with cystitis had low serum antibody levels by IFA and RIA when tested against their own isolate as well as enterobacterial common antigen. The RIA procedure was objective, quantitative, and less tedious to perform than IFA.

Adult↗
PubMed1977

Urinary tract infections in patients with diabetes mellitus. Studies on antibody coating of bacteria.

The prevalence of urinary tract infection was determined in 333 patients attending a diabetes mellitus outpatient clinic during a one-year period. A total of 19% of the women and 2% of the men were found to have urinary tract infections. Antibody-coated bacteria, indicating parenchymal infection, were initially present in 43% of patients and rose to 79% within a mean pretreatment period of seven weeks. In those with recurrent infection following treatment, there were more reinfections than relapses, both in those with kidney infections (67%) and those with bladder infections (57%). The high prevalence of urinary tract infection among diabetic women and the evidence of rapid parenchymal involvement emphasizes the need for clinical awareness of the problem and clarification of its consequences.

Antibodies, Bacterial↗
PubMed1976

Asymptomatic bacteriuria in pregnancy: antibody-coated bacteria, renal function, and intrauterine growth retardation.

Asymptomatic bacteriuria (greater than 100,000 microorganisms per milliliter) was found in 70 of 1,400 pregnant women without symptoms referable to the urinary tract (five per cent). With the fluorescent antibody (FA) tests, antibody-coated bacteria were demonstrated in specimens from 35 patients (50 per cent), indicating silent renal bacteriuria. Although confirmation by direct localization methods was not feasible in this group of patients, indirect evidence of renal function impairment associated with the presence of antibody-coated bacteria was suggested by results of the serum creatinine and creatinine clearance tests. The outcome of the pregnancy was compared for patients with bacteriuria (FA-negative or FA-positive tests). An association between the presence of asymptomatic renal bacteriuria and intrauterine growth retardation was noted. Thus, the patient with asymptomatic bacteriuria and a positive FA test is at greater risk of delivering an intrauterine growth-retarded infant.

Bacteriuria↗
PubMed1975

Bacteriophages and endotoxin in licensed live-virus vaccines.

In confirmation of recent reports, coliphages were found in seven of 19 unselected samples of the currently licensed live-virus vaccines. Coliphages and pseudomonas phage were found in 11 and 14, respectively, of the 20 bovine sera commonly used in the cell culture phase of virus vaccine production. The same lots of vaccine and serum were examined by the limulus assay for endotoxin, another product of bacterial contamination. Eighteen of 20 sera had detectable endotoxin-like activity. Our preliminary results suggest that endotoxin activity may serve as a sensitive indicator of residual products of previous bacterial contamination, including bacteriophages.

Animals↗
PubMed1975

Antibody-coated bacteria in the urine of obstetrical patients with acute pyelonephritis.

The direct immunofluorescence method for the detection of antibody-coated bacteria in urine sediments was used to test urine samples from obstetrical patients with the clinical diagnosis of acute pyelonephritis or cystitis. Antibody-coated bacteria were present in the urine from 12 of 15 patients with acute pyelonephritis, but they were not observed in the urine from 13 patients with cystitis. The clases of antibody coating the bacteria were IgG, IgA, and, in some cases, IgM. A correlation between a high titer of antibody in serum and the presence of antibody-coated bacteria in the urine was noted. These results confirm that the immunofluorescence test can be useful, as previously reported, in distinguishing infection of the kidney from infection of the bladder.

Adolescent↗
PubMed1975

Immunoglobulin levels and antibody-coated bacteria in urines from patients with urinary tract infections.

The presence of antibody-coated bacteria in urines from patients with urinary tract infections has previously been reported to correlate with renal infection as opposed to bladder infection. Urine specimens from 12 patients with pyelonephritis and 12 patients with cystitis were studied to determine whether the antibody coating the bacteria is associated with elevated urine levels of total protein or of particular classes of immunoglobulins. The classes of antibody bound to the infecting bacteria in urines from the patients with pyelonephritis were compared to the levels of unbound antibody in the urine. Each specimen was found to contain antibody-coated bacteria, but not all of the specimens had elevated levels of total protein or immunoglobulins. Thus, the occurrence of antibody-coated bacteria in pyelonephritis did not depend on marked elevations of total urinary protein or immunoglobulins. Studies of patients with cystitis showed that immunoglobulins and protein present in the urines, even in elevated quantities, did not react with the infecting bacteria in patients with bladder infections, as each of these patients had negative FA tests for antibody-coated bacteria.

Antibodies, Bacterial↗
PubMed1975

Simian hemorrhagic fever virus: a new togavirus.

Using the prototype strain of SHF virus, we have confirmed the nature of the genome (RNA), the presence of an envelope (derived from an internal membrane), the virion size (45-50 nm), and probable cubic symmetry. We have also described four viral structural proteins and determined the phospholipid content of the virions. The known properties of SHF virus suggest that it should be classified in the Togavirus family, and possibly in the Flavivirus group.

Animals↗