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J L MELNICK

Publications and source records attributed to J L MELNICK.

At least 145 records · Page 8Linked to original sources
PubMed1956

Sequence of morphological changes in epithelial cell cultures infected with poliovirus.

A sequential study is reported of the cytological changes induced in cultures of monkey kidney epithelial cells by poliovirus. The pattern of cytological changes was followed through a single cycle of virus multiplication. Morphological alterations were correlated with the appearance of new infective virus within the cells and in the culture fluid. Alteration of the chromatin pattern of the nucleus, and Type B acidophilic intranuclear inclusions, were seen as early as 4 hours after virus inoculation. Later wrinkling and shrivelling of the nucleus occurred, and eosinophilic cytoplasmic masses appeared. The rounded, pycnotic cell, customarily used as an index of the cytopathic response, was found only during the last stages of the infective process. On the basis of these changes, infected cells could be classified into six different types. Differential cell counts were made on the stained cultures, and the stage of cytopathic degeneration was correlated with the appearance of virus in the cells and in the culture fluid. Newly formed virus could be detected within the infected cells at about the same time that the first nuclear alterations and intranuclear inclusions were seen. The virus-induced morphological changes exhibited a specificity distinct from the classical pycnosis of autolytic degeneration.

Cell Nucleus↗
PubMed1956

An endemiological study of enteric virus infections: poliomyelitis, coxsackie, and orphan (ECHO) viruses isolated from normal children in two socioeconomic groups.

An endemiological study of enteric viruses was conducted among 136 normal children, living in households in two socio-economic groups, over a 29 month period in Charleston, West Virginia. A repeatable seasonal incidence of enteric virus excretion was noted with over 90 per cent of isolations occurring in the months of June to October. Of 592 stools examined in District I, a lower socio-economic group, 8.3 per cent yielded virus as compared to 3.1 per cent of 966 stools examined in District IV, an upper middle class district with good environmental sanitation. Among the 77 viruses isolated in tissue cultures of monkey kidneys, 44 per cent were ECHO or orphan viruses, 37 per cent Coxsackie viruses, and 19 per cent poliomyelitis viruses. Among poliovirus carriers, and 15 family contacts, 10 individuals had simultaneous heterotypic and type-specific antibody responses. The heterotypic ones were usually present at low levels and were transient in nature. Family infection with certain orphan viruses was also evident from antibody development which occurred following isolation of virus in the sentinel child.

Antibodies↗
PubMed1956

Assay of poliomyelitis neutralizing antibody in disposable plastic panels.

A method for titration of poliomyelitis neutralizing antibodies in disposable plastic panels is described. This method is a modification of those reported from the laboratories of Salk and of McLean, in which antibody is measured by protection of monkey-kidney cell suspensions from the metabolic inhibitory influence of the polioviruses.White polystyrene panels, inexpensive and commercially available, are sterilized by alcohol or ultraviolet light. Only 20,000 to 30,000 passage cells are used per cup. The cell suspension is obtained by treatment of primary kidney cultures with a chelating agent, Versene. Such passage cells have a more uniform metabolic activity than trypsinized cells obtained directly from monkey kidney. Cell suspensions may be stored in the refrigerator for up to three weeks and still prove useful for the colour test. They are standardized for each test by a prior titration of their viability, the results of which are available in less than 24 hours. Both for the primary outgrowth from trypsinized monkey kidney and for the colour test itself, the simple lactalbumin hydrolysate medium is used. Panels are sealed with a paraffin oil of high viscosity.

Antibodies↗
PubMed1955

The cellular changes produced in tissue cultures by herpes B virus correlated with the concurrent multiplication of the virus.

A sequential study is reported of the morphological changes occurring after herpes B virus infection of cells as revealed in ultrathin sections under the electron microscope. Monolayer cultures of renal epithelial cells prepared from the natural host of the virus, the monkey, were infected, and the cellular alterations were correlated with the appearance of infective virus in the culture fluids. The morphological changes consisted in swelling of the cells and disappearance of the nucleolus, followed by margination and gradual decrease of the nuclear chromatin. The inclusion material corresponded to the clear central areas of the nucleus, where the chromatin had disappeared. In the late stages of infection this inclusion material filled the nucleus and formed a classical type A inclusion body. Characteristic particles appeared in the nucleus and cytoplasm of the infected cells a few hours after inoculation. They had a dense center surrounded by one or two membranes. Those with one membrane ranged in size from 60 to 100 mmicro and those with two from 120 to 180 mmicro. Particles showing the same wide variation in size and structure were seen both in the nucleus and in the cytoplasm. They were first visible on the external surface of the swollen but intact cells at about the same time new infective virus became detectable in the culture fluid. A small number of the extracellular, and cytoplasmic, virus particles appeared "binucleated," containing two central bodies, each having its own membrane, both being surrounded by a single external coat. About 180 mmicro in diameter, they were randomly distributed among the "mononucleated" particles.

Herpesviridae Infections↗