CHEMOTHERAPEUTIC ASPECTS OF STUDIES ON BACTERIAL VIRUSES

PEDIATRICS ◽  
1953 ◽  
Vol 11 (2) ◽  
pp. 89-97
Author(s):  
SEYMOUR S. COHEN

MY GREAT pleasure in addressing this body stems in no small part from the fact that this occasion is almost the first indication I have had in 10 years that others besides my immediate chiefs at the Children's Hospital know why I am in a Department of Pediatrics. As many of you are aware, I am a biochemist. It is apparently a surprise to others of my profession that infectious disease is a problem of concern to both pediatricians and biochemists. This attitude, reflecting a tacit belief that the job of a biochemist is to study some esoteric compound, its origin or its fate, rather than chemical aspects of a clearly defined biologic problem is widely prevalent and can be a serious deterrent to the solution of many important medical problems. This is true in the sense that this view affects the general problem of uniting theoretic and practical work. I recall attending the dedication of a virology laboratory last year in which the guest speaker paid tribute to the contributions of research scientists who solved problems in the process of satisfying their intellectual curiosity, as well as to contributions of the research physician who undertook to solve the more practical aspects of the control of disease. It did not seem to have occurred to the speaker that a research scientist might be interested in doing more than titillating his neurones. And of course, in many instances, the speaker was unfortunately correct, since practicality is often viewed as only the unworthy illegitimate child of science, rather than merely as its natural offspring.

1925 ◽  
Vol 44 ◽  
pp. 98-130 ◽  
Author(s):  
A. G. M'Kendrick

In the majority of the processes with which one is concerned in the study of the medical sciences, one has to deal with assemblages of individuals, be they living or be they dead, which become affected according to some characteristic. They may meet and exchange ideas, the meeting may result in the transference of some infectious disease, and so forth. The life of each individual consists of a train of such incidents, one following the other. From another point of view each member of the human community consists of an assemblage of cells. These cells react and interact amongst each other, and each individual lives a life which may be again considered as a succession of events, one following the other. If one thinks of these individuals, be they human beings or be they cells, as moving in all sorts of dimensions, reversibly or irreversibly, continuously or discontinuously, by unit stages or per saltum, then the method of their movement becomes a study in kinetics, and can be approached by the methods ordinarily adopted in the study of such systems.


2020 ◽  
Vol 18 (1) ◽  
Author(s):  
David White

What is Covid-19? Definition: COVID-19 is the infectious disease caused by the most recently discovered coronavirus. It was first recognized in Wuhan, China, in December 2019. Symptoms: The most common symptoms are fever, tiredness, and dry cough. Some people may have aches and pains, nasal congestion, runny nose, sore throat or diarrhea. Course: Symptoms usually begin gradually. Some people become infected but don’t develop any symptoms. Most people (about 80%) recover from the disease without needing special treatment. Around 1 out of every 6 people becomes seriously ill and develops difficulty breathing. At risk: Older people, and those with underlying medical problems. People with fever, cough and difficulty breathing should seek medical attention.


1977 ◽  
Vol 36 ◽  
pp. 143-180 ◽  
Author(s):  
J.O. Stenflo

It is well-known that solar activity is basically caused by the Interaction of magnetic fields with convection and solar rotation, resulting in a great variety of dynamic phenomena, like flares, surges, sunspots, prominences, etc. Many conferences have been devoted to solar activity, including the role of magnetic fields. Similar attention has not been paid to the role of magnetic fields for the overall dynamics and energy balance of the solar atmosphere, related to the general problem of chromospheric and coronal heating. To penetrate this problem we have to focus our attention more on the physical conditions in the ‘quiet’ regions than on the conspicuous phenomena in active regions.


Author(s):  
Adrian F. van Dellen

The morphologic pathologist may require information on the ultrastructure of a non-specific lesion seen under the light microscope before he can make a specific determination. Such lesions, when caused by infectious disease agents, may be sparsely distributed in any organ system. Tissue culture systems, too, may only have widely dispersed foci suitable for ultrastructural study. In these situations, when only a few, small foci in large tissue areas are useful for electron microscopy, it is advantageous to employ a methodology which rapidly selects a single tissue focus that is expected to yield beneficial ultrastructural data from amongst the surrounding tissue. This is in essence what "LIFTING" accomplishes. We have developed LIFTING to a high degree of accuracy and repeatability utilizing the Microlift (Fig 1), and have successfully applied it to tissue culture monolayers, histologic paraffin sections, and tissue blocks with large surface areas that had been initially fixed for either light or electron microscopy.


Author(s):  
Manfred E. Bayer

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.


Author(s):  
Fred Eiserling ◽  
A. H. Doermann ◽  
Linde Boehner

The control of form or shape inheritance can be approached by studying the morphogenesis of bacterial viruses. Shape variants of bacteriophage T4 with altered protein shell (capsid) size and nucleic acid (DNA) content have been found by electron microscopy, and a mutant (E920g in gene 66) controlling head size has been described. This mutant produces short-headed particles which contain 2/3 the normal DNA content and which are non-viable when only one particle infects a cell (Fig. 1).We report here the isolation of a new mutant (191c) which also appears to be in gene 66 but at a site distinct from E920g. The most striking phenotype of the mutant is the production of about 10% of the phage yield as “giant” virus particles, from 3 to 8 times longer than normal phage (Fig. 2).


2003 ◽  
Vol 6 (3) ◽  
pp. 189-197 ◽  
Author(s):  
A. A. Cunningham ◽  
V. Prakash ◽  
D. Pain ◽  
G. R. Ghalsasi ◽  
G. A. H. Wells ◽  
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JAMA ◽  
1966 ◽  
Vol 197 (2) ◽  
pp. 149-150 ◽  
Author(s):  
D. W. Gelfand

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