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Biomedical subjects

J L Melnick

Publications and source records attributed to J L Melnick.

At least 181 records · Page 10Linked to original sources
PubMed1977

Concentration of enteroviruses from estuarine water.

Pleated cartridge filters readily adsorb viruses in estuarine water at low pH containing aluminum chloride. Adsorbed viruses are efficiently recovered by treating filters with glycine buffer at high pH. By using these procedures, it was possible to recover approximately 70% of the poliovirus added to 400 liters of estuarine water in 3 liters of filter eluate. Reconcentration of virus in the filter eluate in small volumes that are convenient for viral assays was more difficult. Reconcentration methods described previously for eluates from filters that process tap water or treated wastewater were inadequate when applied to eluates from filters used to process estuarine water containing large amounts of organic compounds. Two methods were found to permit efficient concentration of virus in filter eluates in small volumes. In both methods, virus in 3 liters of filter eluate was adsorbed to aluminum hydroxide flocs and then recovered in approximately 150 ml of buffered fetal calf serum. Additional reductions in volume were achieved by ultrafiltration or hydroextraction. By using these procedures 60 to 80% of the virus in 3 liters of filter eluate could be recovered in a final volume of 10 to 40 ml.

Adsorption↗
PubMed1977

Occurrence and distribution of bacterial indicators and pathogens in canal communities along the Texas coast.

Increased construction of residential canal communities along the southern coastline of the United States has led to a concern about their impact on water quality. Pollution of such dead-end canals is potentially hazardous because of their heavy usage for recreational activities. Coliforms, fecal coliforms, and salmonellae in the surface water and bottom sediments of six selected residential coastal canals were monitored over a period of 17 months. No statistically significant relationship was observed between the organism concentrations and temperature, pH, turbidity, and suspended solids content of water. An inverse relationship between the concentration of indicator organism and salinity of water was found, however, to occur at a 99.9% level of significance. All of the microorganisms studied were found to be present in greater numbers in sediments than in the overlying water, often by a factor of several logs. Heavy rainfall resulted in large increases in the number of organisms in both water and sediment samples. Our results indicate that bottom sediments in the shallow canal systems can act as reservoirs of enteric bacteria, which may be resuspended in response to various environmental factors and recreational activities.

Escherichia coli↗
PubMed1977

Development of a quantitative method for detecting enteroviruses in estuarine sediments.

Several investigators have reported on the detection of enteric viruses in marine sediments, but none determined the efficiency of their methods and only limited volumes of sediment were sampled. The purpose of this investigation was to develop a quantitative method for detecting enteroviruses in marine sediments so that their relative proportion to viruses freely suspended in estuarine water could be more accurately determined. Poliovirus was found to adsorb readily to natural marine sediments collected along the Texas Gulf coast. A number of substances were evaluated for their ability to elute adsorbed viruses. A solution of 10% fetal calf serum adjusted to pH 10.5 and 0.05M ethylenediaminetetraacetate (pH 11.0) were found to be the best eluents. Using ethylenediaminetetraacetate as an eluent, it was possible to elute virus from large volumes of sediment and reconcentrate the sediment eluate into an economically assayable volume (30 to 50 ml). Poliovirus could be recovered from the sediment with an overall efficiency of 50%. This method was found to be satisfactory for the recovery of naturally occurring animal viruses in estuarine sediments from the upper Texas Gulf coast.

Edetic Acid↗
PubMed1977

Photodynamic treatment of herpes simplex virus during its replicative cycle.

Photodynamic treatment of herpes simplex virus type 1-infected hamster embryo fibroblasts (LSH strain) with a low concentration of proflavine (0.08 mug/10(5) cells per ml), a 3-9-diamine acridine dye, inhibited production not only of infectious progeny but also of virion particles. However, there was no appreciable inhibition of viral or cellular DNA synthesis, even when the infected cells were repeatedly exposed to this low concentration of dye and light during the replication cycle of the virus. It thus appears that photodynamic treatment of infected cells interferes with the processes involved in virus maturation.

Culture Techniques↗
PubMed1977

Concentration of enteroviruses from large volumes of turbid estuary water.

A method is described for the efficient concentration of viruses from large volumes of highly turbid estuary water. Virus in acidified seawater in the presence of aluminum chloride is adsorbed to a 10-in. (about 25.4 cm) fibreglass depth cartridge and 2- and 0.65-micron epoxy-fibreglass filters in series. This filter series is capable of efficiently adsorbing enteroviruses from 50 U.S. gallons (about 190) of estuary water of varying salinity and turbidity. Adsorbed viruses were eluted from the filters with glycine buffer (pH 11.5) and the eluate reconcentrated by using a precipitate formed by the addition of ferric chloride. Viruses were eluted from this precipitate with fetal calf serum. Using this procedure, four different enteroviruses in 50 gallons (about 190) of estuary water were concentrated 9 000- to 12 000-fold with an overall efficiency of 41%.

Aluminum↗
PubMed1977

Lyophilized combination pools of enterovirus equine antisera: preparation and test procedures for the identification of field strains of 19 group A coxsackievirus serotypes.

This paper describes the preparation of seven combination pools of equine antisera, designated J though P, for identification of 19 coxsackievirus A immunotypes. Each pool is composed of 4 to 6 antisera; the serotypes included are A1-6, 8, 10-15, and 17-22. These pools, unlike the previously prepared A-H enterovirus pools, were lyophilized from volumes of 0.5 ml dispensed into 5-ml vials, and when rehydrated with 5 ml of diluent provide 50-antibody-unit material ready for use in identification tests without further dilution. Procedures for using the antiserum pools are given, and guidance is provided for interpreting the results of serum neutralization tests in identifying field isolates.

Animals↗
PubMed1977

Biochemical and biophysical properties of hepatitis B core particles derived from Dane particles and infected hepatocytes.

Hepatitis B core antigen (HBcAg) was purified from Dane particles and from infected hepatocytes. An identical isoelectric pH of 4.0 was determined for labeled preparations of both Dane-derived and liver-derived HBcAg. Unlabeled liver-derived HBcAg demonstrated a lower isoelectric pH of 3.7. Molecular weight determinations by Sepharose 4B column chromatogrpahy revealed that liver-derived HBcAg had a molecular weight of 8.5-9.0 X 10(6) daltons. The sedimentation coeficient of both Dane- and liver-derived HBcAg was found to be 124S. PAGE revealed that iodinated HBcAg derived from Dane particles was very similar in polypeptide structure to HBcAg derived from infected liver tissue. Twelve polypeptides were resolved from Dane core particles, and seven to nine were resolved from liver core particles. Several of the polypeptides in both preparations co-migrated with iodinated hepatitis B surface antigen (HBsAg). However, three polypeptides (mol. wt. 88,000, 79,000 and 59,000) were found in both Dane- and liver-derived HBcAg but not in HBsAg, which suggests that these polypeptides are HBcAg-specific. Endogenous DNA polymerase activity was observed in both Dane- and liver-derived core particles.

DNA-Directed DNA Polymerase↗
PubMed1977

The herpesvirus group.

Several agents in the herpesvirus group are known to infect man. They cause a wide variety of conditions, ranging from coldsores to chickenpox and shingles. At the same time a number of the herpesviruses have been linked with malignant diseases in both lower animals and man.

Animals↗
PubMed1977

Viral vaccines.

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Adenoviruses, Human↗
PubMed1977

Human studies following animal models of tumorigenesis by oncornaviruses.

Similarities have been observed for some time between oncornavirus-induced malignancies in laboratory animals and leukemias and solid tumors in man. Particles similar to type C oncornaviruses have been detected by electron microscopy both in cells or plasma from leukemia patients and in solid-tumor human malignancies such as Hodgkin's lymphoma, lymphosarcomas, and sarcomas. Likewise, particles resembling type B oncornaviruses in shape and appearance have been found in human breast cancer. In neither case has the infectious nature of the particles been confirmed. However, DNA synthesized in vitro by the enzyme of murine mammary tumor virus was found to hybridize with polysomal RNA obtained from human mammary adenocarcinomas. The presence of RNA complementary to RNA from the Rauscher strain of murine leukemia virus has been observed in other human malignancies unrelated to breast cancer. It has also been found that cells of patients with myelogenous leukemia possess an oncornaviral-type reverse transcriptase that is distinguishable from other cell DNA polymerases and serologically related to the reverse transcriptase of primate oncornaviruses.

Animals↗
PubMed1976

Wastewater renovation and reuse: virus removal by soil filtration.

Secondary sewage effluent and renovated water from four wells at the Flushing Meadows Wastewater Renovation Project near Phoenix, Arizona, in operation since 1967, were assayed approximately every 2 months in 1974 for viruses during flooding periods. Viruses, regularly found in the secondary effluent, were not detected in any renovated water samples. Our results indicated that human viral pathogens do not move through soil into the groundwater, but are apparently absorbed and degraded by the soil and reduced in numbers by a factor of at least 10(4) (99.99 percent removal).

Sanitary Engineering↗