Argyrophil cell microneoplasia in the Mastomys' stomach--an observation on early carcinoid formation

To analyze the early stages of argyrophil cell carcinoid growth, complete serial sections were cut from the glandular portion of the stomachs of 22 Mastomys and submitted to Sevier-Munger's reaction. The 154 grossly invisible foci of argyrophil cell microproliferation thus detected were classified into three stages of microproliferations (I, II, and III), and the last stage was definitely a microcarcinoid. There was a gradual transition in cell proliferation among these three stages; the first stage (microproliferation I), in which the cells were morphologically indistinguishable from those of hyperplastic proliferation by general morphologic criteria, was where the initial change of argyrophil cell carcinoid formation was detectable by a light microscope. Whereas multiple occurrences of microcarcinoids accounted for the multiplicity of well-developed tumors in the stomachs of Mastomys, a well-developed carcinoid in this species was formed by the confluence of several microcarcinoids.

Electron microscope study on endocrine cells and tumor cells in the glandular stomach of Praomys (mastomys) natalensis

Endocrine cells in the normal glandular stomach and gastric carcinoids of mastomys were observed by electron microscopy and at least five types of endocrine cells, EC, G, D-like, R (round-granule) and ECL cells were identified. Of these, four types excepting G cells were recognized in the fundic mucosa. Characteristic in mastomys was a scarcity of endocrine cells in the fundic mucosa, where ECL and R cells were predominant types. Silver impregnation methods including SEVIER-MUNGER's argyrophil reaction of our own modifications were applied to tissue sections and the endocrine cells were examined by electron microscopy. Only EC cells revealed argentaffin granules under the light and electron microscope. R, ECL and some of the G cells were non-argentaffin and argyrophil in reaction and D-like cells and the rest of the G cells failed to show even an argyrophil reaction. Granules of mastomys carcinoid cells, as noted in the previous reports, were non-argentaffin but faintly argyrophil. Mastomys gastric carcinoids were studied by the same method, with special reference to the parent cells of this particular neoplasia. Noteworthily, mastomys gastric carcinoids arise mostly from the fundus, the area where R and ECL cells mainly occur in normal animals. The neoplasms are composed of cells containing granules resembling partly those of R cells and partly those of ECL cells. ECL cells and neoplastic cells in the present investigation have a similar reactivity to SEVIER-MUNGER's method. Considering the generally accepted fact that neoplastic cells may not fully duplicate their parent cells in cytological features, it seems reasonable to presume that R and/or ECL cells might be the parent cells of the mastomys gastric carcinoids. In connection with this assumption histamine has been demonstrated to be produced both in mastomys carcinoid cells and normal ECL cells.

Partial purification and properties of guanosine 3':5'-monophosphate-dependent protein kinase from pig lung

Guanosine 3':5'-monophosphate(cyclic GMP)-dependent protein kinase which catalyzes the phosphorylation of histone was purified about 200-fold from the soluble fraction of pig lung by pH 5.5 precipitation, DEAE-cellulose column chromatography, and Sephadex G-200 gel filtration. The apparent Ka values for guanosine 3':5'-monophosphate and adenosine 3':5'-monophosphate were determined to be about 17 and 360 nM, respectively. Mg2+ was essential for the activity exhibiting biphasic stimulation behavior and neither Mn2+ nor Ca2+ could substitute for Mg2+. However, these divalent ions markedly inhibited the protein kinase activity stimulated by cyclic GMP in the presence of Mg2+.

Alpha-methyltyptamine blocks facilitation of lordosis by progesterone in spayed, extrogen-primed rats

Alpha-methyltryptamine, a drug which stimulates serotonergic receptors in the central nervous system, inhibited the induction of sexual receptivity in spayed female rats by estradiol benzoate and progesterone. The drug had no effect on the sexual receptivity induced by estradiol benzoate alone. These data are consistent with the hypothesis that progesterone facilitates lordosis in estrogen-primed rats by inhibiting a serotonergic system in the brain. The data also suggest that estradiol and progesterone act on separate neurochemical systems to induce estrous behavior in rats.

[Spontaneous infection of Hymenolepis nana in hamsters (author's transl)]

Hymenolepis nana (von Siebold, 1852), the dwarf tapeworm causing hymenolepiasis, has been reported to be the common intestinal cestode of rodents and man throughout the world. The authors found spontaneously occurred hymenolepiasis in conventional laboratory hamsters with mass and heavy infections. Some individuals were infected with as many as 188 to 290 worms and in addition, numerous cysticercoids were found in the intestinal villi from the same hamsters. According to the early investigations it is said that there are two ways of infection to rodents. In this study the authors considered a natural autoinfection is to be the case because cysticercoids and immature worms were abundant in the intestines of hamsters. The infection rate of the hamsters was 15% as 6 hamsters were found infected out of 40. All the cases of the heavily infected hamsters showed showed loss of weight and some of them died. Particular damage of the intestinal mucosa was not seen by post-mortem examinations, however, chronic inflammation and destruction of intestinal mucosa caused by the worms observed microscopically (the given pictures). Heavy infection of Hymenolepis nana occurred spontaneously in hamsters has rarely been found in Japan. The case reported here seems to be very peculiar one.