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Biomedical subjects

J L Melnick

Publications and source records attributed to J L Melnick.

At least 127 records · Page 7Linked to original sources
PubMed1982

Immunogenicity of conjugates and micelles of synthetic hepatitis B surface antigen peptides.

A cyclic peptide containing the amino acid sequence 122 through 137 of the major hepatitis B surface antigen (HBsAg) polypeptide was synthesized. The immunogenicity of this synthetic peptide, aggregated in micelles or covalently coupled to tetanus toxoid, was assessed in mice. Antibodies against HBsAg (anti-HBs) were obtained with both preparations, administered either in saline suspension or adsorbed on aluminum gel. The peptide-tetanus toxoid conjugate was more immunogenic than the peptide micelles, producing high levels of specific anti-HBs.

Animals↗
PubMed1982

The role of herpes simplex virus in cervical and vulvar cancer.

This report extends the association of herpes simplex virus type 2 (HSV2) with cervical cancer to vulvar carcinoma. In addition to seroepidemiologic observations linking prior HSV2 infection to genital cancer, the new evidence involves the neoplasms themselves. Biopsies of cervical and vulvar cancers were found to contain HSV2-specified antigens. The virus-induced antigens are nonstructural DNA-binding proteins normally present in the nuclei of infected cells; however, in the cancer cells they were found in the cytoplasm. Whole virus structural antigens were not detected in the biopsies. In recent years there has been a parallel rise in prevalence of HSV2 infections and vulvar carcinomas, particularly in women under 40 years of age, reaffirming the association of the virus infection and the neoplasms.

Animals↗
PubMed1981

Herpesvirus-induced antigens in squamous-cell carcinoma in situ of the vulva.

Antigens induced by herpes simplex virus Type 2 (HSV2) were found to be associated with squamous-cell carcinoma in situ of the vulva in nine of 10 patients. The HSV2-induced antigens are DNA-binding proteins that are normally present in the nuclei of infected cells, but in the cells of the carcinomas in situ they were found in the cytoplasm. Whole-virion structural antigens were not present, although there was serologic evidence of previous HSV2 infection in patients tested for the presence of antibodies. The observations reported here and the recent parallel rise in the prevalence of both HSV2 infections and vulvar carcinoma in situ, particularly in women under 40 years of age, suggest an association of HSV2 infection with this type of neoplasia, the nature of which remains to be determined.

Adult↗
PubMed1981

Immunological and biophysical alteration of hepatitis B virus antigens by sodium hypochlorite disinfection.

Sodium hypochlorite (NaOCl) was examined as an effective disinfectant in hepatitis laboratories. Concentrations of NaOCl containing 5,600 ppm (5,600 microgram/ml) of available chlorine were found to be effective in destroying the antigenicity of hepatitis B surface antigen (HBsAg) in virion-rich plasma after an exposure time of 1 min or more. In the treatment of protein-deficient solutions containing HBsAg, smaller concentrations of available chlorine (less than 500 pm) are equally effective. Neither 17-to 25-nm HBsAg particles nor 45-nm virion particles could be detected by electron microscopy after treatment. chemical interaction of protein and NaOCl was confirmed by isoelectrofocusing of 125I-labeled HBsAg. More than 90% of the labeled material was found at pH 3.0 or lower, indicating complete antigen oxidation. Labeled HBsAg was reduced in density from 1.21 g/cm3 in CsCl to approximately 1.07 g/cm3 after treatment with NaOCl. Both hepatitis B core antigen and deoxyribonucleic acid polymerase activity were significantly reduced after interaction with hypochlorite solutions. These results show that NaOCl destroys hepatitis B antigenicity and virus structures and therefore may be utilized as a disinfectant for the virus.

Centrifugation, Density Gradient↗
PubMed1981

Immunization of chimpanzees with hepatitis B virus-derived polypeptides.

Previous studies established that the purified polypeptides derived from the 22-nm particles associated with hepatitis B surface antigen (HBsAg) produce both humoral and cellular immunity against HBsAg in guinea pigs. Therefore, the two major polypeptides with molecular weights of 22,000 and 25,000 (P22 and P25, respectively) were isolated, adsorbed to an alum adjuvant, and used to immunize four nonimmune chimpanzees. A vigorous anti-HBs response was observed in all four animals after one inoculation of an alum-adsorbed polypeptide vaccine containing 40 micrograms of protein. After one to two booster inoculations, anti-HBs switched from being predominantly immunoglobulin M to the immunoglobin G class, indicating the establishment of immunological memory. Challenge of the vaccinated chimpanzees with 30,000 chimpanzee infectious doses of hepatitis B virus provided evidence for the efficacy of this vaccine. None of the four animals developed serological markers associated with an active hepatitis B infection, and no biochemical or histopathological changes of hepatitis were observed. A nonvaccinated control chimpanzee that was inoculated with the same hepatitis B virus material developed hepatitis B infection, confirming infectivity of the challenge inoculum.

Alanine Transaminase↗
PubMed1981

Colorimetric method for rapid determination of bacteriuria.

An inexpensive, rapid, and simple colorimetric test for detection of bacteriuria is described. This test does not require bacterial growth and has the marked advantage of being able to quantify bacteria, even when the organisms are present in the urine of bacteriuric patients who are being treated with antibiotics. The test is carried out with 1 ml of urine, which is processed through a 10-mm-diameter filter than entraps the bacteria on its surface. Safranine dye is passed through the filter to stain the bacteria and the filter fibers. A decolorizer, which removes the dye from the filter fibers but not from the bacteria, is then passed through the filter. If there are greater than or equal to 10(5) colony-forming units of bacteria per ml in the sample, the 10-mm filter disk manifests a pink to red color. If there are less than 10(5)colony-forming units of bacteria per ml, the filter disk remains white or becomes slightly yellow. The entire procedure has been adapted to a semiautomated instrument and the time required per test is less than 1 min. The results obtained on the test card are a permanent record to be filled with the patient's chart. The bacteria can be quickly classified as gram positive or gram negative by selective staining of a second milliliter of urine on the filter. Of 441 urine specimens tested, 430 (98%) were correctly classified as containing more or less than 10(5) colony-forming units per ml. A total of 62 urine specimens were positive by bacterial plating (greater than or equal to 10(5) colony-forming units per ml), and 59 were positive by the colorimetric test. Eight false-positives (colorimetric test positive, plate counts less than 10(5)) were encountered in patients (bacteriuric) being prescribed antibiotics. Removal of the antibiotics from these urine specimens, with subsequent replating of the samples, indicated the presence of greater than or equal to 10(5) colony-forming units of bacteria per ml in three representative cases tested, indicating that the results of the colorimetric tests were not false-positives but that the plate counts were low because of the inhibition of bacterial growth by the residual antibiotics present in the urine.

Bacteria↗
PubMed1980

Asymptomatic virus shedding after herpes genitalis.

Samples of cervical and vaginal secretions obtained daily from five women were studied for the presence of active virus and/or viral antigens. In women with a history of recurrent genital herpes, either infectious virus or viral antigen in exfoliated cells was repeatedly detected in the absence of overt clinical symptoms. The epidemiologic and obstetric importance of the observations is discussed.

Antigens, Viral↗
PubMed1980

Characterization of HBeAg by physicochemical and immunochemical methods.

HBeAg, which is a hepatitis B-associated antigen, was purified and characterized. The end product from ion exchange, gel filtration and immunoadsorbent columns consisted mainly of immunoglobulin G (IgG) molecules, identified by immunoelectrophoresis and polyacrylamide gel electrophoresis. At least four polypeptides with molecular weights of 55,000, 38,000, 25,000 and 20,000 daltons were detected in four different preparations of HBeAg. Two of these have molecular weights similar to the heavy and light chains of IgG (55,000 and 25,000 daltons). It is postulated that HBeAg may be a small ligand of 20,000 daltons with an affinity for IgG. This affinity, especially if it involves the light chain of IgG, could account for the 38,000 or 42,000 molecular weight polypeptides seen by autoradiography.

Chromatography, Affinity↗
PubMed1980

Infectivity titers of enterovirus as found in human stools.

Data have been gathered and collated from a variety of sources both published and unpublished, dealing with the concentration of enteroviruses in human stools. For polioviruses, a general range of 3.0-6.5 log10 TCD50 per gram of stool was reported, whereas for coxsackieviruses and echoviruses the range has been from 2.0-5.5 log10 TCD50. As human stools average about 100 gm, it is not unusual for an infected person to excrete as much as 10-300 million TCD50 of virus daily. The results of enterovirus titrations are significantly affected by the types of cultures in which the tests are conducted. With certain kinds of cultures (eg, human kidney for polioviruses), comparative tests showed titers to be at least one log unit higher per gram of stoll than the titers of the same strains titrated in monkey kidney cultures. Since almost all of the titrations included in this report were carried out in monkey kidney cultures, the concentration of virus in many cases may be assumed to be ten times higher than that reported. Some of the data collected also contributed information on the duration of enterovirus excretion. These data reemphasize the fact that a person in the course of an asymptomatic enterovirus infection may excrete the virus over a period of many weeks, with about 50% of those infected continuing to shed virus into the third and fourth weeks of infection.

Adolescent↗
PubMed1980

Antigenic relationship of a hepatitis B surface antigen-derived polypeptide and human serum albumin.

Four major polypeptides with mol. wt. of 22000, 25000, 52000 and 68000 were isolated from solubilized preparations of hepatitis type B surface antigen (HBsAg). These four populations, referred to as P22, P25, P52 and P68, respectively, were used to immunize guinea-pigs. Guinea-pigs were also inoculated with HBsAg and with purified human serum albumin (HuSA). These antisera were utilized to establish that intact HBsAg particles are associated with HuSA antigenic reactivity. HuSA antigenic determinants were associated with purified preparations of P68. HuSA antigenic activity was not detected with purified preparations of P22, P25 and P52 or with respective specific antisera to each of the above. However, purified P68 contained the antigenic determinants of both host protein and hepatitis B virus-specified protein origin.

Antigen-Antibody Reactions↗
PubMed1980

Relationships between environmental factors, bacterial indicators, and the occurrence of enteric viruses in estuarine sediments.

Current standards for evaluation of the public health safety of recreational and shellfish-harvesting waters are based upon bacteriological analysis, but do not include an evaluation of the number of viruses. The objective of this study was to determine the occurrence of enteric viruses in estuarine sediments and to find a relationship, if any, between the presence of viruses in seawater or sediment or both and various biological and physicochemical characteristics of the environment. Viruses were found in greater numbers in sediment than in overlying seawater on a volume basis. Several types of enteroviruses were isolated: coxsackievirus types A16, B1, and B5, echovirus type 1, and poliovirus type 2. On several occasions, viruses were isolated from sediments when overlying seawaters met bacteriological water quality standards for recreational use. Statistical analysis of the relationship between viruses in seawater or in sediment and other variables measured yielded only one significant association: the number of viruses in sediment was found to be positively correlated with the number of fecal coliforms in sediment. No other physical, chemical, or biological characteristic of seawater or sediment that was measured showed statistically significant association with viral numbers. No correlation was found between bacterial indicators and virus in the overlying waters. The data indicated that evaluation of the presence of bacteria and viruses in sediment may provide additional insight into long-term water quality conditions and that indicator bacteria in water are not reflective of the concentration of enteric viruses in marine waters.

Clostridium↗
PubMed1980

Humoral and cellular immunity to hepatitis B virus-derived antigens: comparative activity of Freund complete adjuvant alum, and liposomes.

Complete Freud adjuvant, aluminum gel, and liposomes were compared for their ability to enhance the immunogenicity of an intact 22-nm HBsAg particle vaccine and an HBsAg-derived polypeptide vaccine in guinea pigs. Both humoral and cell-mediated immune responses were evaluated. The greatest immune response was obtained with complete Freund adjuvant, regardless of the antigen preparation. Aluminum gel appeared to be a better adjuvant for 22-nm HBsAg particles, but the liposomes rendered polypeptide preparations more immunogenic. The possibility that various proportions were entrapped in aqueous compartments instead of being inserted into the lipid bilayers of liposomes might account for this difference. The development of both humoral and cellular immunity was dependent upon the use of an adjuvant, because aqueous preparations had poor immunogenicity.

Aluminum Hydroxide↗