Changes in plasma glucagon levels to stressful environmental temperatures

Effects of temperature stimuli on plasma glucagon levels were studied in fasted (18 hr) and shorn rats. Plasma glucagon levels rose significantly on exposures to both cold (-5 degrees C, 60 min) (p less than 0.001) and heat (36 degrees C, 60 min) (p less than 0.001) from that in control rats at 25 degrees C. Cold stimulus increased blood FFA level (p less than 0.001) and both cold and heat stimuli increased blood glycerol levels (p less than 0.05-0.001). FFA/glycerol molar ratio decreased to a similar extent on both cold and heat exposures (p less than 0.02-0.01). It was noted that plasma glucagon, blood FFA and glycerol levels increased significantly more in cold-exposed rats (p less than 0.001) than in heat-exposed ones. There were positive relations of plasma glucagon levels to blood FFA and glycerol levels (p less than 0.001), while an inverse relation of plasma glucagon level to FFA/glycerol molar ratio was observed in all experimental rats (p less than 0.05). Cold exposure reduced blood glucose level (p less than 0.001), while heat exposure did not affect it. Cold-induced increases of plasma glucagon and blood FFA levels were diminished significantly in cold-acclimated rats as compared with those in controls (p less than 0.05-0.001). Blood glycerol increased and FFA/glycerol molar ratio decreased to a similar extent on cold exposure in both control and cold-acclimated rats. Correlation between plasma glucagon and FFA/glycerol molar ratio was inversely significant in controls, but not significant in cold-acclimated rats. Blood glucose level was not altered on cold exposure in cold-acclimated rats. It was concluded that acute exposures to temperature stimuli, especially to cold, stimulate glucagon release, accompanied by increased utilization and mobilization of FFA and glucose, and plasma glucagon response to cold is diminished due to cold acclimation.

The possibility of centrifugal projections to the retina in the rat

In rats, glutamic acid decarboxylase activity increased in the proximal portion of the optic nerve after its ligation, whereas the activities of choline acetyltransferase and tyrosine hydroxylase remained constant. Possible centrifugal neurons to the retina are GABAergic.

Recombinant plasmids containing avian vitellogenin structural gene sequences derived from complementary DNA

Purified mRNA coding for chicken vitellogenin, a precursor of egg yolk proteins, was transcribed to complementary DNA (cDNAvit) with avian myeloblastosis virus (AMV) reverse transcriptase. Double-stranded cDNA was synthesized with Escherichia coli DNA polymerase I (fragment A) using the self priming ability of the cDNA. Following S1 nuclease digestion the double-stranded cDNA was inserted into the Hind III site of plasmid pBR322 using the poly(dA) . poly(dT) tailing method, and the hybrid molecules were used to transform Escherichia coli chi 1776. Ampicillin-resistant colonies were screened by colony hybridization with 125I-labeled vitellogenen mRNA. Further screening of positive clones was done by agarose gel electrophoresis and in situ hybridization with 125I-labeled vitellogenin mRNA. In addition, plasmid DNA covalently bound to diazotized paper was used to select complementary mRNA sequences. The cloned vitellogenin sequences were shown to hybridize to a mRNA which directs the synthesis of immunoprecipitable vitellogenin when translated in a reticulocyte lysate cell-free system. The length of the inserted cDNA was determined by agarose gel electrophoresis and heteroduplex mapping. The largest insertion was about 2500 base pairs. Restriction mapping indicates that at least three plasmids out of four have different sequences.

Possible role of polyamines in the function of brown adipose tissue

In order to ascertain possible involvement of polyamines in the physiological regulation of brown fat function, effect of temperature acclimation on the polyamine contents of this tissue and effects of polyamines on the noradrenaline-induced thermogenesis is isolated brown adipocytes were investigated in rats. Daily urinary excretion of polyamines measured collectively for spermidine and spermidine per body weight was decreased in heat acclimation and increased in cold acclimation. Polyamine concentrations per fresh weight of brown fat showed extremely low values compared with those of other tissues previously reported. Putrescine and spermidine contents per fat-free dry matter of brown fat were decreased in cold acclimation, but were not affected in heat acclimation. Spermidine and spermine inhibited the noradrenaline-induced thermogenesis of brown adipocytes dose-dependently. These results suggest that polyamines regulate the heat production of brown adipose tissue in an inhibitory way and cold acclimation potentiates heat production of this tissue by reducing polyamine levels.

Characterization of factors stimulating differentiation of mouse myeloid leukemia cells from a Yoshida sarcoma cell line cultured in serum-free medium

A clone, YS-T22, of cells from Yoshida sarcoma cell line, YSSF-212T, grown in "serum-free" culture medium produced factors stimulating differentiation of mouse myeloid leukemia cells (M1) to macrophages and granulocytes. The formation of macrophages and granulocytes was accompanied by induction of phagocytosis, locomotive activity, and lysosomal enzyme activities. The rates of induction of these differentiated phenotypes were proportional to the concentration of the factor added and the period of treatment. The factor stimulating differentiation of M1 cells was a heat-labile, nondialyzable proteinaceous substance that was inactivated by trypsin but not by ribonuclease or glycosidases. On diethylaminoethyl cellulose chromatography, the factor stimulating differentiation of M1 cells from conditioned medium of YS-T22 cells was eluted in various fractions with or without activity of the colony-stimulating factor.

Plasma branched-chain amino acids in cold- and heat-acclimatised rats

The concentrations of plasma branched-chain amino acids, valine, isoleucine and leucine, were significantly elevated in cold-acclimatised rats, while these values were significantly reduced in heat-acclimatised rats, in both 2-week and 4-week temperature acclimatisation.

Strict relationship between dialyzed serum concentration and cellular life span in vitro

To determine the extent of the contribution of growth factor level on the life span of human diploid fibroblasts in vitro, the growth rate changes of IMR-90 cells under altered dialyzed serum (d-FBS) concentrations were investigated at different population doubling levels (PDL). As the PDL increased, the cells showed an accelerated requirement for d-FBS in order to maintain a constant growth rate, thus indicating a rapid loss of responsiveness of the cells to serum growth factors. A similar relationship was observed when the growth rate was extrapolated to zero and the cellular life span was predicted from this relationship. The cells cultured with 0.3% and 10% d-FBS ceased their growth at 54 and 76 PDL, respectively, while their predicted life span was 58 and 80--85 PDL, respectively. The cells cultured with 0.3% d-FBS responded poorly to an increase in the d-FBS concentration after entering phase III. These results suggest that the serum growth factor level is one of the determinants of cellular life span in vitro.

[Clinical experience with ampicillin-cloxacillin (Viccillin S 'Meiji') by intravenous drip infusion in gynecological infections (author's transl)]

Ampicillin-cloxacillin (Viccillin S 'Meiji') by intravenous drip infusion was used in gynecological infections, with the following satisfactory results. 1) The drug was markedly effective in 2 out of 6 cases, effective in 4, being the efficacy rate 100%. 2) No abnormal laboratory findings and side effects were observed in our study.

Pontine and non-pontine pathways mediating early mossy fiber responses from sensorimotor cortex to cerebellum in the cat

Stimulation of the cat's sensorimotor cortex evokes a short-latency mossy fiber field potential (N2) in the pars intermedia of the cerebellum. The fraction of the response carried by each of the six cerebellar peduncles was determined by comparing the field potentials before and after electrolytic lesions of individual cerebellar peduncles. The response evoked from the contralateral cerebrum is 3.5 times as large as that evoked from ipsilateral cerebrum. The size of the N2 wave from contralateral cerebral cortex is reduced to about half of the original size after electrolytic lesion of either the brachium pontis (BP) or the restiform body (RB) ipsilateral to the recording site, while only a small reduction in the size of N2 is observed after lesions of contralateral BP and RB. This indicates that inputs responsible for the generation of the N2 wave from contralateral cerebral cortex enter the cerebellum primarily through ipsilateral BP and RB. In contrast, the N2 wave from ipsilateral cerebral cortex is reduced by approximately one quarter following lesions of any one of the four RB's and BP's. Fibers in the brachium conjunctivum do not contribute to these responses. Observation on the P2 field potential, representing postsynaptic firing of granule cells, suggest that the cerebro-ponto-cerebellar and cerebro-reticulo-cerebellar mossy fiber pathways converge onto granule cells. Furthermore, these two inputs must arrive within 3 ms of each other in order to activate the granule cells. In addition, it is shown that BP lesions reducing the mossy fiber input lead to an increase in the climbing fiber input.

Immunohistochemical evidence for RNA virus related components in human breast cancer

The localization of antigenic components with cross-reactivity to a 52,000 dalton group specific glycoprotein (gp52) of the mouse mammary tumor virus (MMTV) in paraffin sections of human breast carcinomas is described using an indirect immunoperoxidase method. This method was first optimized on paraffin sections of mouse mammary tumors. The specificity of the reaction observed in the human tissues was established by absorption of the specific IgG with: a) purified gp52; b) several relevant and irrelevant viral preparations; c) normal human plasma, leukocytes, breast tissue, milk, actin, collagen, and hyaluronic acid; d) sheep erythrocytes, bovine mucin and fetal calf serum. Only MMTV and purified gp52 eliminated the immunohistochemical reaction in human breast tumors. Positive reactions were seen in 171 of 376 (45.5 percent) randomly selected breast carcinomas of various histopathologic types, while negative reactions were obtained in all 137 normal and benign cases tested. In those invasive tumors with an intraductal component, a higher percentage (63.9 percent) of positive cases was seen. A positive reaction of different specificity was observed in foci of apocrine metaplasia. With one exception, 99 carcinomas from 13 organs other than breast and eight cystosarcomas were negative.