The incorporation of 51Cr-3, 4-dihydroxyphenylalanine (DOPA) complex into melanoma B 16

Summary The complex is accumulated by the tumors as well as by the adrenal glands of the tumor-bearing mice. Although in adrenals a higher uptake was found with L-DOPA complex, no significant differences are observed in the tumor between L-DOPA and D,l-DOPA complexes. The incorporation of the ⁵¹Cr-DOPA complex shows a general pattern like those obtained with ¹⁴C and ³H labelled DOPA by other authors.

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Zusammenfassung Der Komplex wird sowohl im Tumor als auch in den Nebennieren der tumortragenden Mäuse angereichert. Während in den Nebennieren eine größere Anreicherung des L-DOPA-Komplexes gefunden wurde, ergaben sich im Tumor keine Unterschiede zwischen der Aufnahme von L-DOPA und D,l-DOPA Komplexen. Die Aufnahme dieses ⁵¹Cr-DOPA-Komplexes entspricht im allgemeinen demjenigen, das von anderen Autoren mit ¹⁴C und ³H markiertem DOPA beobachtet wurde.

     

Characterization of Mycobacterium leprae by lipid analysis

The lipid composition of the leprosy bacillus, harvested from experimentally infected nine-banded armadillos, strongly supports it status as a distinct species of the genus Mycobacterium. Phthiocerol dimycocerosate waxes and glycosylated phenophthiocerol dimycocerosates are distinct from those characterised from a number of other mycobacteria. The polar lipids of a single isolate lack diacylated forms of phosphatidylinositol di- and pentamannosides, lipids usually found in most mycobacteria. A simple mycolic acid pattern composed of alpha-mycolates and ketomycolates is characteristic of most preparations of M. leprae.     

Decrease of the 3,4-Dihydroxyphenylalanine (DOPA) Decarboxylase Activities in Human Erythrocytes and Mouse Tissues after Administration of DOPA

Human erythrocytes have been found to contain appreciable amounts of DOPA decarboxylase (EC 4.1.1.26) activity. The enzyme activity in erythrocytes from patients with Parkinson's disease who were treated with DOPA was significantly lower than that of untreated patients and of normal individuals. Administration of the drug to mice led to a marked decrease of DOPA decarboxylase in liver and kidney, but not of the brain enzyme. The findings thus indicate that administration of DOPA leads to a decrease in peripheral DOPA decarboxylase, an effect that is expected to be of benefit in DOPA therapy of patients with Parkinson's disease. Peripheral DOPA decarboxylase concentration also decreases in mice after short periods of fasting; the findings suggest that the peripheral enzyme activities may be affected by various nutritional and perhaps hormonal influences, which may be partially responsible for the observed fluctuations in the motor abilities of Parkinsonian patients receiving constant doses of the drug. Study of DOPA decarboxylase activity in erythrocytes may be useful in following changes in patients receiving DOPA therapy and may also be of general interest and value in investigations of catecholamine metabolism in man.     

Decarboxylation of 3,4-Dihydroxyphenylalanine (DOPA) by Erythrocytes: A Reaction Promoted by Methemoglobin and Other Ferriheme Proteins

The decarboxylation of DOPA by erythrocyte hemolysates differs from DOPA decarboxylation catalyzed by aromatic aminoacid decarboxylases that contain vitamin B(6) in several significant respects. The ability of erythrocyte hemolysates to decarboxylate DOPA is associated with interaction between DOPA and methemoglobin; the ferriheme protein is reduced and DOPA is decarboxylated, probably after oxidation to a quinone intermediate. An analogous reaction takes place between DOPA and other ferriheme proteins, such as metmyoglobin and cytochrome c. This phenomenon may be of significance in relation to the side effects observed in patients with Parkinson's disease who are treated with very large doses of DOPA.     

Replication of Mycobacterium leprae in hibernating ground squirrels (Citellus tridecemlineatus)

Subcutaneous injections of 10(6) acid-fast bacteria from human lepromatous tissue to hibernating ground squirrels (Citellus tridecemlineatus) is followed by generalized infection of the animals and spontaneous death. The number of mycobacteria is high in the skin of GS during winter and decreases during summer. Animals surviving the first hibernation period invariably die during the second. The number of microorganism in the visceral organs is low at all times. The system of infected hibernating GS is a valuable model for the experimental study of leprosy.     

Intracellular parasitism of parenchymal cells by Mycobacterium leprae

The liver, skeletal muscle, and adrenal gland obtained from two nine-banded armadillos infected with Mycobacterium leprae were studied using an electron microscope. M. leprae were found in varying numbers inside hepatocytes, Kupffer's cells, striated muscle cells, adrenal cortical and adrenal medullary cells, endothelial cells, and macrophages. There was evidence to suggest that M. leprae were actively phagocytosed by the liver and skeletal muscle cells. The inert nature of M. leprae and its behavior as an almost ideal parasite of parenchymal cells are emphasized. The question of whether this unique parasitism of parenchymal cells and the possible processing and presentation of M. leprae antigens by these cells could be responsible for aberrant immune responses is raised.     

Effect of lysozyme on Mycobacterium leprae

Because large amounts of lysozyme are present in phagocytes, it was selected, as one of the bactericidal substances, to study the in vitro effects on M. leprae. The results obtained led the author to conclude that M. leprae is not susceptible to lysozyme as many other atypical as well as attenuated pathogenic mycobacteria. This resistance of M. leprae to lysozyme was seen up to a level of 100-500 micrograms per ml, while levels of 1000 micrograms and more had very significant effect; the ATP content of such treated M. leprae declined to 30% of the original levels in 5 days of incubation at 37 degrees C, with optimum pH of 6.0, and these M. leprae after such exposure to lysozyme failed to multiply in the foot pads of mice. The interpretation of these results, though not definitive, have been discussed.     

Abortive infection of Mycobacterium leprae by the mycobacteriophage D29

The interactions of mycobacteriophage D29 and Mycobacterium leprae were examined. It was demonstrated that after adsorption D29 injected its DNA in M. leprae. While the synthesis of host proteins and lipids were inhibited in M. tuberculosis and in M. smegmatis during infection by D29, the results were inconclusive in the case of M. leprae because these bacteria did not incorporate the appropriate substrates.     

In vitro activation of neutrophils by suspensions of Mycobacterium leprae.

Activation, defined as an increase in the proportion of cells that reduce nitroblue-tetrazolium in vitro, is present in neutrophils from patients with reactional lepromatous leprosy but not in neutrophils from patients with non-reactional lepromatous leprosy. Neutrophils from patients with all forms of leprosy are equally well activated by endotoxin in vitro. We have now shown that in vitro activation induced by Mycobacterium leprae suspensions is of comparable magnitude in neutrophils from patients with all forms of leprosy (including lepromatous and reactional lepromatous leprosy). There is no intrinsic neutrophil anergy in patients with lepromatous leprosy vis-à-vis M. leprae as pertains to activation. Spontaneous activation in reactional lepromatous leprosy is likely due to an indirect mechanism, probably of immunologic nature, and not simply to the presence of circulating Mycobacterium leprae in the blood.     

Growth of Mycobacterium leprae in nude mice

Athymic nude mice were introduced in our laboratories in 1982. In this paper results over one year period of nude mice inoculated with small numbers of M. leprae are described. In this study we showed that 1 X 10(4) M. leprae with low numbers of viable bacilli inoculated into hind foot pads of nude mice housed both in vinyl plastic isolators and "clean room" conditions had the ability to grow and reach remarkable levels. There was dissemination of the infection to other uninoculated foot pads by six months.     

Electron microscopic study of Mycobacterium leprae membrane

We report the results of the study by transmission electron microscopy of normal Mycobacterium leprae in the tissues of experimentally infected armadillos. Several fixation procedures were used and compared to those previously employed in the study of M. leprae in lepromatous leprosy patients. The results show that the ultrastructure of M. leprae is identical in both hosts. The demonstration of a symmetric membrane profile in M. leprae in armadillos confirms our previous results. This characteristic of the M. leprae membrane is peculiar in that it is not shared by any of the easily cultivable species of mycobacteria we have studied so far.