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Changes of some ultrastructural parameters (paracrystalline structures, Golgi apparatus, secretory granules) in mole pinealocytes were quantitatively studied during the various phases of the sexual cycle. An increase in quantity of paracrystalline structures and of the Golgi appratuses was demonstrated during the period of high sexual activity in male pinealocytes and during oestrus, gestation and lactation in female pinealocytes. Moreover, the appearance of vacuoles in female pinealocytes was observed during pro-oestrus. These results seemto demonstrate close relationship between the endocrine activity of the hypophyseo-gonadal axis and the synthesis of some compounds by the pinealocytes. No increase in the quantity of secretory granules was observed during the various phases of the sexual cycle studied. Key words: pinealocytes, mole, sexual cycle, ultrastructure, paracrystalline structure.

The response of a human malignant melanoma cell line in vitro to high linear energy transfer radiation was studied utilizing the neutrons produced by the reaction of 16 and 50 MeV deuterons on beryllium. The relative biological effectiveness (RBE) relative to cobalt-60 gamma radiation was determined under conditions of complete oxygenation. The data indicate that the radioresistance ascribed to malignant melanoma in vivo is not an intrinsic quality of the cell but rather may be mediated by the in vivo environment.

Neutron dosimetry intercomparison visits have been made by physicists from the M. D. Anderson Hospital-Texas A&M University Project to the Naval Research Laboratory, the University of Washington, and the MRC Cyclotron at Hammersmith Hospital. The Naval Research Laboratory and University of Washington physicists have made dosimetry intercomparisons at the Texas A&M Variable-Energy Cyclotron (TAMVEC). The parameters that are usually measured during these visits are tissue kerma in air, tissue dose at depth of dose maximum, relative central-axis depth dose, neutron/gamma ratios in air and in phantom, and photon calibrations of ionization chambers. In addition, beam profiles and dose buildup curves are sometimes measured. Other parameters that are compared are values of W, stopping power ratios, kerma corrections, and calculations that lead to the statement of tumor doses for patients. This paper presents some of the results of the intercomparisons and discusses the implications of the findings.

The growth-inhibition test was used to detect specific antibodies against Leptospira interrogans serotype hardjo in isolated immunoglobulin (IgG and IgM) fractions of serums from cattle vaccinated with leptospiral bacterins. The growth-inhibiting antibodies were detected mainly in the IgG class. Agglutinated clumps also occurred with the IgM fraction. The serums collected from cattle 4 months after vaccination were negative in the microscopic agglutination test.

An indirect hemagglutination test was developed to detect naturally occurring eperythrozoonosis in swine and to follow experimentally induced infections serologically. The antigen used was prepared from the plasma of acutely infected, splenectomized pigs. The test was specific and reliable in detecting swine latently infected with the disease.

Changes in the number of autofluorescent and serotonin-containing pinealocytes have been studied after gonadotropic hormone administration using fluorescence histochemistry. Moreover, the 5-HT levels in the pineal gland were determined biochemically under the same experimental conditions. The results suggests that pineal 5-HT levels are not influenced by increased gonadotropin levels, while the amount of autofluorescent pinealocytes increases after gonadotropin injections. It has been postulated that differences in androgenic hormone levels could not cause the changes in the number of autofluorescent pinealocytes. The reaction of the pineal gland to increased gonadotropin levels seemed important in view of the regulatory function of the epiphysis on the hypothalamo-hypophyseo-gonadal axis.

Using the fluorescence histochemical technique, yellow autofluorescent granules were observed in neurones of the arcuate and ventromedial hypothalamic nuclei of the rat (type I cells). In the same nuclei, neurones could be demonstrated showing a formaldehyde-induced yellow fluorescence (type II cells). Microelectrophoresis and special staining methods applied to the pineal gland revealed the autofluorescent compound to be a protein containing a relatively high content of tryptophan. It is probable that the formaldehyde-induced yellow fluorescence is due to the presence of serotonin. In view of investigating a possible functional relationship between the pineal gland and the parvocellular hypothalamic nuclei mentioned, hypothalamic type I and type II cells, as well as autofluorescent and serotonin-containing pinealocytes, if present, were quantified under the following experimental conditions: (1) p-chlorophenylalanine (pCPA) administration, (2) castration, (3) pinealectomy, and (4) pinealectomy followed by substitution using rat and sheep pineal extract. Administration of pCPA caused a decrease in the number of type II and an increase in the number of type I cells, both in the pineal gland and the hypothalamic nuclei. Castration, in contrast, was followed by an increase in the number of autofluorescent pinealocytes, but a decrease of autofluorescent neurones in the hypothalamic nuclei (type I cells) while the number of serotonin-containing pinealocytes increased; decreasing in both hypothalamic nuclei. After pinealectomy the hypothalamic nuclei showed an increase of type I neurones, but a decrease of type II nerve cells. Pinealectomy followed by substitution using pineal extracts restored the number of type I and type II neurones to that normally found in the arcuate and ventromedial hypothalamic nuclei of control animals. The present investigation brings histological evidence of an influence exerted by the rat pineal gland on nuclei forming part of the hypothalamic hypophyseotropic area. The data obtained and some of the literature strongly suggest that the type II neurones, which probably contain serotonin, inhibit, in the same hypothalamic nuclei, the production of luteinizing hormone-releasing factor (LH-RF). As yet, the function of the autofluorescent compound present in the type I neurones is not known.

Studies of the depth-ionization properties and the biological effects of heavy ion beams produced at the bevatron have extended work previously done with less energetic beams from other sources. Results indicate that heavy ion beams are suitable for tumor therapy, studies relating to space biology, and fundamental radiobiology.

1. A cell-free system from Pseudomonas fluorescens catalysed the oxidative demethylation and subsequent ring-cleavage of vanillate, with uptake of 2.5 moles of oxygen/mole of substrate. 2. Demethylation involved absorption of 0.5 mole of oxygen/mole, and required reduced glutathione (GSH) and nucleotide (probably NADPH) as cofactors, with further possible requirements, the natures of which are discussed. 3. Incomplete evidence suggested that the aromatic ring was opened via protocatechuate and the appropriate oxygenase, with absorption of 1 mole of oxygen/mole of substrate, eventually yielding beta-oxoadipate. 4. The methyl group was removed sequentially as formaldehyde, formate and carbon dioxide, the steps catalysed respectively by formaldehyde dehydrogenase, which required GSH and NAD(+), and formate dehydrogenase. Each enzyme was cytochrome-linked and accounted for absorption of 0.5mole of oxygen/mole of substrate. 5. All enzymes except formate dehydrogenase, which was a cell-wall enzyme, resided in the soluble fraction of the extract. The demethylase could not be resolved because of unknown cofactor requirements.