Spontaneous cell-mediated cytolysis by peripheral blood cells obtained from whole-body chronically irradiated beagle dogs

The level of natural killer (NK) activity of continuously gamma-irradiated (whole body) beagle dogs and their nonirradiated controls was studied. For analytical purposes, irradiated dogs were segregated into groups according to their clinical status: clinically normal, hypocellular, or with acute non-lymphocytic leukemia. Since unirradiated control animals exhibited a wide range of NK responses, the data from each irradiated animal were compared to its own age-matched or litter-matched unirradiated control. Of the eight clinically normal irradiated dogs (median = 146% activity of control) only one animal had a NK activity lower than that of its control. The hypocellular group (n = 5, median = 21.8% of control) and the leukemic group (n = 4, median = 52.5% of control) each contained one responder with higher activity than its control. The difference between the percentage of control of the clinically normal and clinically abnormal dogs was found to be significant (P less than 0.05). There is a negative correlation between the NK results obtained and the total accumulated dose of radiation at the time of sampling (correlation coefficient = -0.739, P less than 0.01), suggesting a radiation effect upon natural killer activity, which is evidence by enhancement at lower doses and depression at higher doses of irradiation.     

Selective accumulation of heavy metals by microorganisms

Summary An investigation of the removal and recovery of urnnium from aqueous systems using microbial biomass has been described previously (Nakajima et al. 1982). To establish which microorganisms accumulate the most uranium, we extended our investigation of uranium uptake to 83 species of microorganisms, 32 bacteria, 15 yeasts, 16 fungi and 20 actinomycetes. Of these 83 species of microorganisms tested, extremely high uranium-absorbing ability was found in Pseudomonas stutzeri, Neurospora sitophila, Streptomyces albus and Streptomyces viridochromogenes.The selective accumulation of heavy metal ions by various microorganisms has also been examined. Uranyl, mercury and lead ions were readily accumulated by almost all the species of microorganisms tested. Actinomycetes and fungi differ from many bacteria and most yeasts in their selective accumulation of uranium and mercury.In addition to this fundamental research, uranium recovery was investigated in immobilized Streptomyces albus, a microorganism with high uranium-uptake ability. These immobilized cells adsorbed uranium readily and selectively. The immobilized cells recovered uranium almost quantitatively and almost all uranium absorbed was desorbed with 0.1 M Na₂CO₃. The dry weight of the free cells decreased by 50% during 5 adsorption-desorption cycles. However, the dry weight of the immobilized cells decreased by only 2% during 5 cycles. These results showed that microbial cells are more stable after immobilization and can be used repeatedly for the process of uranium adsorption-desorption.     

H1° histones of normal and cancer human cells

Summary H1° histones were purified by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis from human lung carcinoma (line DMS79), human hepatoblastoma (HepG2), human adult lung and human adult and fetal liver. The purified human H1° histones were analyzed for their amino acid composition and terminal residues. The comparative analysis of the amino acid compositions of the different human H1° histones showed that: (a) all the H1° preparations have the characteristically high lysine content associated with a low arginine content, which distinguishes outer histones from core histones; (b) H1° is distinguishable from other H1 histones by the presence of methionine and histidine; (c) H1° histones from human adult, fetal and cancer cells are very similar in amino acid composition, and in cancer cells the level of the H1° histone is not inversely related with cell growth rate nor with the expression of the -fetoprotein gene.     

Glucagon-related peptides in the rat hypothalamus

Summary Immunohistochemically, nerve fibers and terminals reacting with anti-N-terminal-specific but not with anti-C-terminal-specific glucagon antiserum were observed in the following rat hypothalamic regions: paraventricular nucleus, supraoptic nucleus, anterior hypothalamus, arcuate nucleus, ventromedial hypothalamic nucleus and median eminence. Few fibers and terminals were demonstrated in the lateral hypothalamic area and dorsomedial hypothalamic nucleus. Radioimmunoassay data indicated that the concentration of gut glucagon-like immunoreactivity was higher in the ventromedial nucleus than in the lateral hypothalamic area. In food-deprived conditions, this concentration increased in both these parts. This was also verified in immunostained preparations in which a marked enhancement of gut glucagon-like immunoreactivity-containing fibers and terminals was observed in many hypothalamic regions. Several immunoreactive cell bodies were found in the ventromedial and arcuate nuclei of starved rats. Both biochemical and morphological data suggest that glucagon-related peptides may act as neurotransmitters or neuromodulators in the hypothalamus and may be involved in the central regulatory mechanism related to feeding behavior and energy metabolism.     

“SIF” cells in the sympathetic ganglia of the bullfrog,Rana catesbeiana: variety in population and innervation

Summary Small intensely fluorescent (SIF) cells appeared singly or, more frequently, in variably-sized clusters in the sacroccygeal 8th and 9th sympathetic ganglia of the bullfrog. Smaller clusters containing only two to nine SIF cells accounted for 61% of 1773 clusters examined. The largest cluster contained 283 cells. The number of cells in individual ganglia also varied from 21 to 3332. SIF cells, solitary as well as in smaller clusters, received no distinct form of the synaptic contact. In contrast, the cells in larger clusters were frequently innervated by nerve endings that were similar in vesicular constitution to the nerve endings on principal ganglion (PG) cells. No synaptic contact was found between SIF cells and PG cells. SIF cells were also characterized by their location in the vicinity of blood capillaries with a continuous endothelium. p]Our observation seems to suggest that larger clusters of SIF cells receiving nerve endings are linked to a paracrine and/or endocrine system. Chemical influence via the blood stream and intraganglionic milieu for non-innervated SIF cells in the solitary or smaller clusters is a subject for speculation. An interneuronal role of SIF cells to relay stimuli to PG cells seems unlikely. The possible functions here assigned to SIF cells could be variable in efficiency depending on their population and density.     

Effects of degranulation of mast cells on proliferation of mesenchymal cells in the mesentery of mice

Summary A mast-cell activator, compound 48/80, causes proliferation of mesenchymal cells in the mesentery of rats. Its effect on W/W ^vmice deficient in mast cells was tested to determine whether the proliferation is mediated in the degranulation of mast cells. Incorporation of [³H]thymidine into mesenchymal cells in the mesentery of these mice with or without compound 48/80 was very small compared to their normal litter mates. However, bone marrow transplantation markedly enhanced the effect of compound 48/80, and resulted in an incorporation of [³H]thymidine almost comparable to that observed in normal mice. Our results provide evidence that mesenchymal cell proliferation is caused by a product secreted by mast cells when stimulated by compound 48/80.Supported by a Grant-in-Aid for Scientific Research, No. 366, from the Japanese Ministry of Health and WelfareThe authors are indebted to Drs. Motomu Minamiyama and Yukio Hirata for valuable advices, and to Miss Mitsuko Inoue for technical assistance     

Morphological appearance of epidermal cells cultured on fibroblast-reorganized collagen gels

Summary Human foreskin fibroblasts were used to reorganize hydrated collagen gels into a dermal-like matrix, after which freshly isolated keratinocytes isolated from rabbit ear skin were placed on the surfaces of the matrices and cultured for up to 12 days. Transmission electron microscopy revealed 8–12 cell layers of epidermal cells organized in three distinct strata. The basal stratum consisted of cuboidal to columnar cells with typical complement of organelles, oval nuclei, and prominent tonofilaments inserting into desmosomes. Mitotic cells often were found at this level. There was no well-defined basement membrane region; rather, many of the cells appeared to be in close contact with collagen fibrils. The intermediate stratum of suprabasal cells consisted of elongated cells that had reduced organelles, but still were connected to each other by desmosomes. Finally, the superficial stratum of suprabasal cells contained cells that were completely flattened and often appeared to be sloughing off the apical surfaces of the cultures. Indirect immunofluorescence studies carried out on frozen sections revealed bullous pemphigoid antigen associated with basal epidermal cells; pemphigus vulgaris antigen around the epidermal cells of all strata, and keratin present in the epidermal cells of all strata. Filaggrin was observed in punctate and fibrillar arrangements in suprabasal cells. Fibronectin was found in a linear deposit at the dermal-epidermal junction and around the fibroblasts in the reorganized collagen gels. Type-IV collagen and laminin, however, were not detected.     

Detailed profile of prolactin secretion in the immature female rat: evidence for the existence of an ultradian rhythm

The detailed profile of prolactin (PRL) secretion in 22-24 and 29-31 days old female rats was investigated by serial blood sampling through an intracardiac cannula at 15-min intervals for each of the 9 or 10-h periods beginning at 09.00 or 10.00 and 22.00 h. By analysis of the power spectrum and the least squares method the time series of PRL concentrations which were measured by RIA were found to have approximately a 3-h period ultradian rhythm in either sampling period of both the 22-24 and 29-31 days old rats. The peak times calculated based on the acrophase estimated through the calculation of periodicity were concentrated around 12.00, 15.00 and 18.00 h for the sampling period 10.00-19.00, and 24.00, 03.00 and 06.00 h for the sampling period 22.00-07.00 h. However, in more than half of the animals at 22-24 days of age, one secretory episode around 12.00 h, and two secretory episodes around 24.00 and 03.00 h had markedly small amplitudes, making the remaining secretory episodes distinct diurnal and nocturnal surges, respectively. In the animals at 29-31 days of age, the amplitudes of the PRL episodes occurring around 12.00 h were markedly small, making the remaining two episodes as diurnal surges, whereas the amplitudes of PRL secretory episodes during the period 22.00-07.00 h were analogous to each other. These findings indicate that the semicircadian rhythm of PRL secretion is established on the basis of PRL secretion with the 3.0-h period ultradian rhythm.     

Effect of gamma-aminobutyric acid on excitability of tubero-infundibular neurons in rat hypothalamic slices

The effect of gamma-aminobutyric acid (GABA) on antidromically identified tubero-infundibular (TI) neurons was examined in hypothalamic slices of ovariectomized female rats. Twenty antidromically evoked spikes were obtained in the medial basal hypothalamus, including the arcuate and ventromedial nuclei, by electrical stimulation of the median eminence. Sixteen of them had a notch in the rising phase and fractionation of the initial segment (IS)- and somatodendritic (SD)-spikes was elicited by repeated stimulation at frequencies higher than 10 Hz. The application of 0.5-1.5 mM GABA to the incubation medium inhibited SD spikes in 7 of these 16 neurons. The latency, amplitude and threshold of IS spikes were not affected by GABA except for one spike whose latency fluctuated. On the remaining 9 neurons having the notch, no effect of 5-10 mM GABA was discernible. Four of 20 antidromically evoked spikes, which had a smooth rising phase and a shorter duration, were not inhibited by 5-10 mM GABA, but a fluctuation of the latency was observed in one neuron. Fifteen neurons having spontaneous unit activity were also obtained in the arcuate nucleus and its adjacent area and tested with GABA. In 10 of the 15 neurons, spontaneous unit activity disappeared following 0.1-1.5 mM GABA perfusion, while the firing rate in the remaining 5 neurons was not affected by 5-10 mM GABA. These results provide evidence for a direct inhibitory effect of GABA on TI neurons and support the involvement of GABAergic neurons in regulating neuroendocrine functions.