Disease has changed since 1812. People have different diseases, doctors hold different ideas about those diseases, and diseases carry different meanings in society. To understand the transformations of disease over the past 200 years, one must explore its social nature.

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The burden of disease and the changing task of medicine

Improvements in high speed electronics and scintillation-crystal technology now permit usable differential time-of-flight measurements to be made in tomography systems that employ coincidence detection of the annihilation photons created with positron emitting radionuclides. A mathematical model for these new measurements is developed in this paper. Reconstruction algorithms and their signal-to-noise ratio performance are given.

A Matheematical Model for Positron-Emission Tomography Systems Having Time-of-Flight Measurements

The hyperventilation produced by increasing H+ concentration in the cerebrospinal fluid of dogs was first described by Leusenl-s and confirmed by Winterstein and Gokhan.4m They thought that the hyperventilation resulted from direct stimulation of the respiratory centers. Loeschcke and co-workerss confirmed their results and attempted to locate the site of the stimulation. They found the maximum acid-sensitivity to be in the region of the lateral recesses of the 4th ventricle or in the adjacent subarachnoid space near the roots of the 8th-10th cranial nerves. They also demonstrated that dilute solutions of veratradine in this region also caused hyperventilation, whereas lobeline, cyanide, or procaine depressed ~entilation.T-~ Sergievski and Okuneva,lo who also produced hyperventilation in dogs by introducing acidic cerebrospinal fluid into the ventricles, concluded that the reactive area was on the surfaces of the lateral ventricles. However, the respiratory responses in their studies were much smaller than those described by other workers. Our investigaton is an examination of the hypothesis that the superficial int,racranial chemoreceptors may be the site of the respiratory response to inhaled C02. We have attempted to localize the region of chemosensitivity and to determine its quantitative relationship to the respiratory response to inhaled CO2.

Regions of respiratory chemosensitivity on the surface of the medulla

Challenges for the female academic during the COVID-19 pandemic.

Effects of local cooling upon conduction and synaptic transmission

IN recent months public anxiety and confusion over the possibility and consequences of thermonuclear war have been increased and deepened by extensive (and often conflicting) publicity in newspaper...

Human and ecologic effects in Massachusetts of an assumed thermonuclear attack on the United States.

A slender refrigeration probe for the production of reversible discrete lesions within the central nervous system of man and experimental animals is described. Cooling, in the region of the third nerve nucleus in cats, produced pupillary dilatation which was quickly reversed when the temperature around the third nerve nucleus returned to normal.

https://science.sciencemag.org/content/sci/134/3489/1520.full.pdf

Localized cooling in the brain.

Positron-emitting isotopes of arsenic and copper, injected intravenously, were used for the localization of braiiwn tumors and other intracranial lesions. Scanning was accomplished by coincidence counting of the paired annihilation gamma rays from the positron-emitting copper or arsenic. The biological reactions of inorganic arsenate and arsenite and of copper vetsenate in man are discussed. Radioassay of biopsies of the principal normal cephalic tissues, of various types of neoplasms, of hematomas, abscesses, and zones of demyelination was carried out. Concentrations of isotopes were increased in all tumors. Hematomas, abscesses, and large zones of demyelination also had concentrations high enough to permit localization in the majority of patients. The results of more than 3000 scans on 334 patients are summarized. A correct diagnosis was made in 80% of 249 tumors scanned with arsenic and in 70% of 84 tumors scanned with copper. 19 references. (C.H.)

Saul Aronow

Papers

Human and ecologic effects in Massachusetts of an assumed thermonuclear attack on the United States.

Localized cooling in the brain.

Localization of focal intracranial lesions by scanning of rays from position-emitting isotopes.

[The use of computerized tomography in the detection of intra-orbital foreign bodies].

Air leaks as a source of distortion in apexcardiography.