ANTI-EGG ALBUMIN ANTIBODY IN THE HORSE

The reaction between three times recrystallized egg albumin and its antibody in the horse has been studied. The reaction exhibits a behavior typical of the Ramon diphtheria flocculation reaction

FUCHSINOPHILE GRANULES IN THE TISSUES OF MICE INFECTED WITH THE CONNECTICUT-5 STRAIN OF COXSACKIE VIRUS

Minute cytoplasmic fuchsinophilic granules, characteristically surrounded by a halo, have been demonstrated in the lesions produced in suckling mice by the Connecticut-5 strain of Coxsackie virus. Their possible significance is discussed

THE EFFECT OF EXPERIMENTAL REDUCTION OF KIDNEY SUBSTANCE UPON THE PARATHYROID GLANDS AND SKELETAL TISSUE

Reduction of renal tissue in young rats regularly leads to a marked increase in the volume of the parathyroid glands. If partially nephrectomized rats are maintained on a low calcium diet, growth is stunted, and skeletal lesions are produced, of far greater severity than can be ascribed to the dietary calcium deficiency alone. The picture closely resembles that found in cases of renal rickets in children

EXPERIMENTAL RICKETS IN RATS : VI. THE ANATOMICAL CHANGES WHICH ACCOMPANY HEALING OF EXPERIMENTAL RAT RICKETS, UNDER THE INFLUENCE OF COD LIVER OIL OR ITS ACTIVE DERIVATIVES.

Rats which had developed rickets were treated with cod liver oil or an active fraction of cod liver oil, and the various changes which occur in the healing of the bone lesions were studied. Several phases are described, from the early deposit of calcium salts in the zone of preparatory calcification to the return to normal bone. These stages correspond closely to those found in the healing of human rickets

NUTRITIONAL MUSCULAR DYSTROPHY IN THE GUINEA PIG AND RABBIT

A diet is described, which leads to a progressive, highly selective, and ultimately fatal dystrophy of the voluntary muscles. Guinea pigs and rabbits are susceptible, rats resistant. The diet used is complete in known requirements, except for vitamin E; the addition of this factor, however, does not prevent the development of the disease. The lesions are not due to inanition, infection, or scurvy, and must be referred to some still unknown factor

FURTHER EXPERIMENTS UPON THE EFFECTS OF EXTIRPATION OF THE THYMUS IN RATS, WITH SPECIAL REFERENCE TO THE ALLEGED PRODUCTION OF RACHITIC LESIONS

Rachitic changes in the bones and teeth occur in young albino rats as the result of spontaneous disease, possibly of infective origin. This disease is often, but not always, accompanied by an arrest of growth and malnutrition. There is no valid reason for attributing such lesions to the loss of thymic function. In some of the rats showing the disease, an unusual number of mitoses were found in the parathyroid glands, but no evidence of injury to these structures. It has not been found possible to confirm the statements of Klose and Magnini as to the fatal effects of complete thymus extirpation in rats

THE EFFECTS OF EARLY EXTIRPATION OF THE THYMUS IN ALBINO RATS

It has been shown that white rats may survive complete extirpation of the thymus for at least 131 days, even when the operation is performed within the first two weeks of life. Removal of the thymus does not produce an arrest or retardation of body growth and development. Qualitative changes in the skeletal system or teeth have not been found. In emaciated, weak animals osteogenesis is less active than in healthy rats, and the long bones are smaller and more delicate in structure. Such quantitative differences appear to depend upon the general nutrition, are equally pronounced in rats whose development is retarded from other causes, and cannot be referred specifically to loss of thymus function. No constant or characteristic alterations were detected in the spleen, testes, adrenals, or thyroid. Whatever functional correlations may exist between thymus and any or all of these organs are not evident from the occurrence of histological changes after the removal of the thymus. The relative proportion of lymphocytes in the blood is diminished for the first few weeks after the operation. We have not determined how long this alteration in the leucocytic formula persists. Since this paper went to press an article has appeared by Klose, describing briefly the results of thymus extirpation in pigs, goats, rats, and chickens. In rats thymectomized on the fourteenth day, there followed a progressive cachexia terminating in death after eight to ten weeks. Disturbances in ossification, which macroscopically and microscopically were identical with those of human rickets, developed also in the ribs and long bones. Some of Klose's litters failed to show these lesions, and this negative result is explained as having been due to the presence of thymic tissue within the thyroid gland. The observations of Klose are in direct contradiction to the negative results described in this paper. Since the possible presence of accessory thymus tissue either within the thyroid or elsewhere was carefully excluded in my experiments, the discrepancy between my findings and those of Klose cannot be explained upon this basis. Since this paper was sent to the publisher I have studied two additional rats which were killed 185 days after operation. Minute examination of a complete series of the neck organs, including the thyroid, failed to show any tissue which could be interpreted as thymus. The bones showed no rachitic changes. The infective origin of rachitic and osteomalacic lesions in rats has been established by Morpurgo. Although reference is made by Klose to Morpurgo's work, the data given by him do not enable one to judge whether this infection was definitely excluded

THE ANTIRACHITIC ACTION OF COD LIVER OIL AND IRRADIATED ERGOSTEROL IN PARATHYROIDECTOMIZED AND THYMECTOMIZED RATS

Cod liver oil and Viosterol in therapeutic doses are antirachitic in the absence of the parathyroid gland, or of the thymus, or of both

STUDIES ON THE MODE OF ACTION OF DIPHTHERIA TOXIN : IV. SPECIFICITY OF THE COFACTOR (NAD) REQUIREMENT FOR TOXIN ACTION IN CELL-FREE SYSTEMS

The ability of a number of nucleotides related to NAD to replace NAD as cofactors for inhibition by diphtheria toxin of peptide bond formation has been examined. Neither NADH nor NADP are active. Of some 14 analogues closely related structurally to NAD that have been tested, only 3-thiocarboxamide pyridine-AD is as active as NAD itself. Replacement of the 3-carboxamide group on the pyridine ring by an acetyl group, or deamination of the purine ring, resulted in derivatives with reduced activity. The results were interpreted as suggesting that NAD and certain related nucleotides are capable of specific interaction with diphtheria toxin. Using the method of equilibrium dialysis, reversible binding of 1 mole of NAD per mole of toxin has been demonstrated. Toxoid does not interact with NAD