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Biomedical subjects

H A Gaafar

Publications and source records attributed to H A Gaafar.

At least 37 records · Page 2Linked to original sources
PubMed1978

Detection of antibodies to Neisseria gonorrhoeae by counterimmunoelectrophoresis.

Antigen was partially purified from Neisseria gonorrhoeae B370 saline wash and used to assay human sera for the presence of antibodies to N. gonorrhoeae. The antigen activity as monitored by counterimmunoelectrophoresis (CIE) is resistant to trypsin and papain but sensitive to heat and periodate oxidation. Of the sera from patients with bacteriologically confirmed cases of gonorrhea, 80% were positive by CIE using this antigen preparation. Of the sera in the negative control group 11% were reactive.

Antibodies, Bacterial↗
PubMed1978

Babesiosis: malaria mimic.

Human infection with blood parasites of the genus Babesia can result in a hemolytic disease very similar to malaria. Laboratory diagnosis of babesiosis is dependent upon the detection and identification of the parasite in blood films. The distinguishing criteria are: lack of pigment in infected red blood cells; no circulating schizonts or gametocytes; "atypical" malarialike organisms; tetrad groups, rods, or exclamation-mark forms; and persisting parasitemia after treatment for malaria.

Animals↗
PubMed1978

Gonorrhea card test: an agglutination test for uncomplicated gonorrhea.

An antigen extracted and purified from Neisseria gonorrhoeae B370, type 4, was employed to sensitize charcoal particles for use in an agglutination assay of human sera for antibodies that indicate active gonorrheal infection. The screening card test is more sensitive than the fluorescent gonorrheal test-heated (FGT-H), especially in men. A simple one-step absorption improved the specificity without reducing the sensitivity of the test.

Agglutination Tests↗
PubMed1977

Purification of Neisseria gonorrhoeae surface L-antigen.

A purified preparation of the L-antigen of Neisseria gonorrhoeae with a 40-fold increase of antigenic activity over the crude extract was prepared. The antigen was extracted from the cell envelope by mild treatment with sodium dodecyl sulfate and purified by Sepharose 4B, diethylaminoethyl-cellulose, and diethyl-(2-hydroxypropyl)aminoethyl (QAE)-Sephadex column chromatography. The purified antigen was heat labile and trypsin sensitive. The smallest antigenically active subunit appeared to have a molecular weight of 38,500, as shown by polyacrylamide gel electrophoresis of the product incubated with sodium dodecyl sulfate.

Antigens, Bacterial↗
PubMed1977

The role of plasma cells in scleroma. Electron-microscopic study.

Three cases of rhinoscleroma in the granulomatous stage were examined under the electrom microscope. The rough endoplasmic reticulum of plasma cells in scleroma displayed cisternal dilatations forming Russell bodies and cytoplasmic vacuolations containing viable and degenerated bacilli forming Mikulicz cells. Thus, they play a double role, producing antibodies and providing protection for the intracellular bacilli. New ultrastructural findings of Klebsiella rhinoscleromatic bacilli were described.

Humans↗
PubMed1976

Bacteriocin production by Neisseria gonorrhoeae.

Seventeen apparently unrelated isolates of Neisseria gonorrhoeae out of 2,123 tested produced a diffusible growth-inhibitory substance against other gonococci. The inhibitor was destroyed by trypsin, not blocked by bovine serum albumin, and not soluble in chloroform-methanol; each isolate was resistant to the inhibitor it produced. Thus, the substance differs from previously described gonococcal inhibitors, and since it fits the description of a bacteriocin we designated it gonocin. The use of gonocin for typing was complicated by the observation that susceptibility to gonocin appears to depend on the gonococcal colony type.

Bacteriocins↗
PubMed1976

Fluorescent antibody test for the serological diagnosis of gonorrhea.

An indirect fluorescent antibody technique has been developed for the serological diagnosis of gonorrhea. The selected strain(s) of Neisseria gonorrhoeae possesses a heat-labile surface antigen (L-antigen). Sera are diluted 1:10, and an aliquot is hear inactivated at 59 C for 30 min. The treated and untreated aliquots are then examined for human immunoglobulin G anti-L-antigen. In a prelimiary study of 495 sera, 95% of those from women with a bacteriologically confirmed diagnosis of gorrhea and 87% of those from male patients were reactive in this test, whereas only 1.4% fo the sera from presumably normal individuals were reactive.

Antibodies, Bacterial↗
PubMed1976

Evaluation of the fluorescent gonococcal test-heated.

In a 1-year evaluation of the indirect fluorescent antibody test for gonorrhea, 16,127 specimens from low-and high-risk groups were examined, and the results were compared with culture, history of exposure to a known patient, and clinical signs and symptoms. The results confirmed the usefulness of the indirect fluorescent antibody test for gonorrhea as a screening procedure, especially for women in the low-risk group. The test is more economic and probably more sensitive than culture for mass screening of asymptomatic women.

Adult↗
PubMed1975

Selective interaction of Neisseria gonorrhoeae and Candida albicans and its possible role in clinical specimens.

A study of 27 clinical specimens from which Neisseria gonorrhoeae and Candida albicans were isolated simultaneously indicated that 44% of the gonococcal isolates were resistant to inhibition by the C. albicans with which they were found and an additional 33% were totally resistant to inhibition by all C. albicans tested. All 27 C. albicans showed inhibitory activity against standard indicator strains of N. gonorrhoeae.

Antibiosis↗
PubMed1975

Gonorrhea screening program in New York State.

Of 171,089 mailed specimens examined for Neisseria gonorrhoeae, 88% were submitted by family planning clinics, physicians in private practice, and other non-VD clinics. To process a large volume of specimen bottles, we developed a swab-oxidase test and demonstrated it to be reliable for the initial screening of all specimens. Our protocol permitted the isolation and confirmation by sugar fermentation of 95% of all presumed N. gonorrhoeae cultures within 1 or 2 days after growth was observed. The results obtained over a 2-year period indicate that the positivity rate is directly related to the lag period between specimen collection and examination. There was no adverse effect of cold weather on the positivity rate, but, irrespective of the season, 3 to 9% of the positive specimens required incubation for 3 days before gonococcal growth appeared.

Gonorrhea↗
PubMed1974

Inhibition of Neisseria gonorrhoeae by a factor produced by Candida albicans.

When Candida albicans is present on Transgrow specimens, Neisseria gonorrhoeae is detected less frequently or else can be seen in Gram stains but cannot be readily cultured. When C. albicans and N. gonorrhoeae are grown together on Transgrow, the gonococcal cells die off much more readily than N. gonorrhoeae grown on Transgrow alone. By use of a cross-streaking technique on agar plates, it has been demonstrated that C. albicans produces a soluble substance inhibitory to N. gonorrhoeae, although not to other microorganisms tested. Preliminary results indicate that this inhibitory factor can be extracted by the use of tertiary butanol. Since approximately one-third of the Transgrow specimens with growth contains yeasts, of which C. albicans is by far the most frequent, this factor presents an important complication in the diagnosis of gonorrhea in women.

Anti-Bacterial Agents↗
PubMed1974

Detection of Escherichia coli antigens by a latex agglutination test.

A latex particle agglutination technique to detect ethylenediaminetetraacetate-solubilized extracts from Escherichia coli and whole E. coli cells is described. The sensitivity of the serological test was found to be 0.5 to 2.5 ng for the solubilized antigens and 1.5 x 10(6) to 5.7 x 10(6) cells per ml for the particulate antigens. The test was 100 to 1,000 times more sensitive than the standard bacterial agglutination test. Furthermore, it detected E. coli antigens during all phases of bacterial growth, whereas the bacterial test detected the antigens only after the mid-log phase. No significant cross-reactivity was observed between latex-anti-E. coli preparations and heterologous bacterial strains used in the experimental procedure. A buffer formula containing fatty acid-free bovine albumin prevented nonspecific aggregation of the latex particles.

Agglutination Tests↗