Esmond R. Long

Experimental studies on nutrition in tuberculosis. The role of protein in resistance to tuberculosis.

Summary The results of Experiment II were like those of Experiment I, the chief difference being that the infection was better regulated, and variations within the 3 protein groups were more characteristic. Tuberculosis was less extensive and life was much longer in the rats on a 40% protein diet than in the other 2 groups, and the degree of localization of the disease was better. The number of bacilli in lesions was smaller in the 40% series and the extent of pneumonia was less. Corresponding with the lesser extent of pneumonia there was less dissemination of tuberculous lesions. A characteristic feature of the long-lived animals was a progressive change in the cellular type of reaction from an early infiltration of mononuclears with little cytoplasm to a stage of consolidation with epithelioid cells and finally to a “regressive” type of mononuclear reaction in which lesions decreased in size, epithelioid cells were few and mononuclears with little cytoplasm predominated.

A standardised tuberculin (purified protein derivative) for uniformity in diagnosis and epidemiology

Summary o (1) The use of tuberculin as a diagnostic agent in epidemiology and clinical practice has increased considerably in recent years. With the further drop in infection incidence that may be expected, a still greater diagnostic value is to be anticipated. (2) In view of this probable increase in the use of tuberculin, standardisation permitting more accurate comparison of data than is at present possible with the variable preparations on the market, seems timely. (3) Old Tuberculin, a sample of which has been arbitrarily selected as an International Standard, logically might receive first consideration as a basic substance for a standard tuberculin, because of its proven specificity and long history of successful application in epidemiology. (4) Old Tuberculin, however, cannot be made uniformly, because of inherent inconstancies in its manufacture. The various preparations of Old Tuberculin are inevitably solutions of unknown strength of an active principle. Therefore it is logical to separate the active principle from Old Tuberculin and use this substance in solutions of known strength. (5) The active principle of Old Tuberculin can be isolated by a method outlined in the text of the is article, and put up in dry form such that the essential requirements of a standard, viz., specificity, high potency, constancy in strength and stability, are ensured. The active principle as it exists in Old Tuberculin is a protein derivative, the exact chemical composition of which is under investigation. In its present refined form it has been designated simply Purified Protein Derivative from tuberculin. (6) Optimum dosages of this substance for epidemiological work and testing of child and adult tuberculous patients, have been established on the basis of several thousand tests. The doses selected are 0·00002 mg. by weight of the Purified Protein Derivative for the initial test, and 0·005 mg, for injection of those failing to react to the first dose. Experience has shown that the small first dose detects all the highly sensitive cases, without danger of excessively severe reactions, while the second dose defects the remainder of positive cases, that is, those whose sensitiveness is such that they would respond to the conventional doses of preparations of tuberculin of strength equal or superior to that of the International Standard. (7) Several series of tests in the United States, England and Wales, are here reported, in some of which comparison with Old Tuberculin and X-ray findings is recorded. The X-ray examinations indicate that the Purified Protein Derivative, like other tuberculins, may fail to defect an occasional case of healed primary tuberculosis with calcified foci, but that cases of clinical significance are not missed. (8) The incidence of positive tuberculin reactions to the Purified Protein Derivative in surveys in England and Wales varied from 38 per cent. in children 16 years of age or less in an orphan asylum, to 100 per cent. in a tuberculosis sanatorium for adults. Almost all adult patients with tuberculosis reacted to the small first dose. (9) In the United States during the fall of 1934 the Purified Protein Derivative was used in testing about eight thousand college students in various parts of the country. The results are significant, because, for the first time, the tuberculin used on various groups of college students was uniform. In the east about 50 per cent, of the students reacted positively in the middle-west 25 to 30 per cent, and on the west coast about 50 per cent.

A RETROSPECTIVE REVIEW OF MYCOBACTERIA AND THE DISEASES THEY CAUSE

For practical purposes the mycobacteria are the acid-fast bacteria, i.e., bacteria that are somewhat difficult to stain in the first place, and still more difficult to destain, usually requiring acid, and frequently acid and alcohol, to accomplish that purpose. A fully adequate definition of mycobacteria is more complicated, and unnecessary here. Mycobacteria have much more in common than acidfastness. Some of the characteristics mutually possessed will come out later in this conference.

Accumulation of Chlorophyll Pigments in Visceral Organs and their Elimination.

Summary Chlorin-e-rhodin-g was very slowly eliminated from the tissue of rabbits after intravenous injection. The major portion of that deposited in the spleen and bone marrow after a month of administration was still present in phagocytic cells 3 months later. Somewhat greater elimination occurred from the liver. The deposit in the hemopoietic organs had no evident effect on their function.

The Incidence and Prevention of Tuberculosis in American Schools and Colleges.

Summary Reference is made to certain representative studies indicating the trend of tuberculosis in American clementary and high schools, and colleges and schools of medicine and nursing. No attempt has been made to present a complete review of the numerous papers in this field. In the elementary and high schools, studies continued over a decade indicate that the proportion of children positive to the tuberculin test is steadily falling. In the less crowded communities the drop is more striking than in large, congested cities. The incidence in rural communities is generally significantly lower than in urban areas, and differences within the same community are always found corresponding to the economic level. Important tuberculous disease is first met to an appreciable extent in high school students, where the combined incidence of latent and manifest disease varies from 1·5 to nearly 3·0 per cent, being higher among girls. Important disease demanding care occurs in from 0·5 to 1·0 per cent of these children. Active programmes for the early detection and control of tuberculosis in schools now operate throughout the country. The basic principles of these programmes are mass tuberculin testing, x-ray examination of the positive reactors, and provision of suitable care for those found to have lesions. In the colleges, according to an intensive study by the Committee on Tuberculosis of the American Student Health Association, about 6 students per 1,000 have tuberculosis of the adult type, or probably 6,000 students in all American colleges. The average incidence of infection for the country as a whole is about 30 to 35 per cent. A marked variation occurs geographically, students from the great central portion of the country having a relatively low incidence. The programme for control is similar to that operating in public schools, but as a rule more comprehensive, including full-time health departments. Tuberculosis is recognized as the most serious disease of the college period, yet as insidious in onset, requiring routine massmeasures for its detection. It is encouraging that most of the lesions now discovered are in the minimal stage. Students of medicine and nursing are now known to be subject to a special hazard. The danger for medical students seems greatest during the third and fourth, or clinical years, suggesting that tuberculosis acquired in the medical school is usually exogenous. The programme for prevention is similar to that in schools and colleges, but all investigators urge that examinations should be more frequent than seems necessary in earlier years, and radiological examination is regarded as indispensable. Most nurses who are tuberculin-negative on beginning training become positive to tuberculin during their course. The incidence of clinical tuberculosis is also proportionately high as compared with other professional or working groups at the same age, both during the period of training and in the first years after qualification. As with medical students, frequent radiological examination is considered imperative. It is encouraging that, whereas the development of significant tuberculous infection in nurses is frequent, early detection and prompt arrest result from the application of a proper programme for tuberculosis control in the training schools.

The purines and purine metabolism of tumors, and the chemical relations of primary and secondary tumors

The purines of both benign and malignant tumors are the same as those found in normal tissues, and they exist in much the same relative proportions, The proportion of the total nitrogen of tumors which is constituted by the purine nitrogen is less than would be exspected from the histological evidence of the amount of nuclear material contained in the tumors. Tumors seem to contain much the same purine enzymes as the normal tissues. Thus, guanase seems universally present in tumors derived from human tissues, and adenase is missing, although autolyzing tumors can disintegrate their nucleic acid (nuclease) and change the adenine radicals of the nucleic acid into hypoxanthine, presumably by way of adenosine and inosine (Amberg and Jones). Secondary tumors growing in the human liver do not acquire the enzyme, xanthine-oxidase, which is a characteristic enzyme of this organ. The liver tissue between the cancer nodules seems to oxidize purines less actively than normal liver tissue. In view of the peculiarities of the distribution of purine enzymes in different species, we have examined a number of tumors of the domestic animals, obtained from the Chicago Stock Yards. The results of these investigations will appear in an early number of the Journal of experimental medicine.

A pathologist's recollections of the treatment, investigation, and control of tuberculosis.

The last fifty years have seen great changes in the prognosis and treatment ofpulmonary tuberculosis, once the most widely fatal of all human ailments, a disease that has cost the world heavily in lives and health, expense of prolonged medical care, and personal and family sacrifice. The story of the decline in tuberculosis is colorful and dramatic and fortunately has been put on record in many accounts that are inspiring as well as informative.

Effect of Chlorin-e-Rhodin-g on Experimental Tuberculosis.∗

Summary Chlorin-e-rhodin-g inhibited the growth of tubercle bacilli in vitro, but had no effect on the course of experimental tuberculosis in rabbits. The pigment accumulated in large quantity in phagocytic cells in the spleen and bone marrow. Pigmented cells were frequently concentrated on the border of tubercles, but did not appear to function as epithelioid cells and rarely were found containing tubercle bacilli.

Microincineration of tubercles.

The technic of microincineration as developed by Policard 1 and modified by Scott 2 has been used in studying the mineral content of tubercles from human tuberculosis and experimental tuberculosis in guinea pigs. Alternate serial paraffin sections were stained and ashed. The ashing process was carried out in a muffle furnace at a temperature of approximately 540°, about 4 hours being allowed for the incineration. The general observation made by previous investigators that the nucleus is the part of the cell richest in ash, was confirmed. The distinction was found to be conspicuous in the tuberculous spleen, where the mineral-rich Malpighian corpuscles stood out sharply against a mineral-poor background, the latter being found by comparison with the stained sections to consist of aggregations of epithelioid cells. In general the epithelioid cell cytoplasm was found low in ash. As a rule regions of degeneration and recent necrosis were found to contain less ash than the corresponding undegenerated tissue. This was the case in guinea pig tubercles, acute tuberculous pneumonia in man and chronic fibrocaseous human tuberculosis. A peribronchial tubercle (guinea pig) in the corresponding stained and ashed sections is shown in the accompanying figure (Fig. 1). It will be noted that the center of the ashed tubercle contains somewhat less mineral than the outer zones, and that this region corresponds to a spot of early degeneration in the stained tubercle. It seems reasonable to attribute the loss of mineral to karyolysis and diffusion away of soluble mineral material. In later stages of the human disease remineralization of necrotic tissue could be observed. In sections of experimental tuberculosis kindly furnished by Dr. Spies, taken from tuberculous rabbits given intensive oral treatment with viosterol, the speed of this process was found to be much enhanced (compare with other results of Spies 3 ).