Effects of methylmercuric chloride of low concentration on the rat nervous system.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
T Satoh
Publications and source records attributed to T Satoh.
Immunohistochemically demonstrated increase in glutathione S-transferase species in propylnitrosamine-induced focal proliferative and neoplastic Syrian hamster pancreatic lesions.
Immunohistochemical investigation of focal proliferative and neoplastic Syrian hamster pancreatic lesions induced by propylnitrosamine administration revealed a distinct pattern of expression of different molecular forms of glutathione S-transferase (GST) during neoplastic development. Initial increase in levels of GST placental (P) and B forms in early ductal/ductular proliferations and atypical (dysplastic) lesions was followed by a drop in the latter during transition to carcinoma. Unequivocal acinar cells observed within so-called 'pseudoductules' did not share the altered phenotype evident in ductular elements, suggesting their non-involvement in the generation of early lesions. However, the fact that component cells were occasionally of abnormal morphology did not allow the exclusion of acinar cell participation in histogenesis. Elevation of GST-A and C forms was limited to stromal elements surrounding the epithelial lesions and since they were associated with benign, cystic as well as atypical lesions and a similar increase was observed after common duct ligation, they appeared to be non-specific. The results indicated independent control of expression of individual GST forms and suggest that biochemical similarities exist between early, putative preneoplastic lesions induced by propylnitrosamines in the hamster lung, liver (both hepatocellular and intrahepatic bile duct) and pancreas.
Animals↗
Fetal-type creatine kinase in rat fast and slow muscles during denervation and reinnervation.
Creatine kinase (CK) has three forms of isozymes; CK-BB, CK-MB, and CK-MM. In adult rats they show a specific tissue distribution: the BB form in the brain, the MB form in the heart, and the MM form in skeletal muscle. In embryonic skeletal muscles only the BB and MB forms are found. Adult slow-twitch muscles contain more fetal type creatine kinase (CK-B) than do fast-twitch muscles. In the present experiment the effect of denervation and reinnervation on the CK-B concentration was investigated in rat fast (extensor digitorum longus)- and slow (soleus)-twitch muscles by a highly sensitive immunoassay. Denervation of these muscles produced a progressive increase in CK-B concentration in both muscles. When the sciatic nerve was cut and immediately sutured, the CK-B concentration in both muscles showed a gradual reduction after an initial increase. By the 34th postoperative week the CK-B concentration in the soleus was about one-half that of the contralateral control, whereas that in the extensor digitorum longus was nearly normal. After cross union of the nerves innervating the muscles, the CK-B concentration in the soleus was reduced at 35 weeks to about one-half normal, but that in the extensor digitorum longus was always higher than the control value. After self-reunion of the nerves, the CK-B concentration at the 20th week was approximately normal in the extensor digitorum longus and significantly increased in the soleus. We suggest that the motoneurons normally innervating the extensor digitorum longus have a greater capability in suppressing the production of CK-B than do the soleus motoneurons.
Animals↗
Relationship between positive sharp wave bursts and unitary discharges in the cat hippocampus during slow wave sleep.
In the cat hippocampus bursts of positive sharp waves (PSWs) appeared sporadically almost exclusively during slow wave sleep. The PSW burst was most often found in cell-rich areas in the CA1 and subiculum, and its occurrence was almost synchronized in different regions. An individual burst was usually composed of 3-5 PSWs of about 10 msec duration and showed a considerable fluctuation in amplitude. It was occasionally followed by a negative-going deflection of large amplitude and long duration (post-PSW negativity). The amplitude of PSWs and post-PSW negativity in the CA1 was high in the area giving a large sized-evoked response after stimulation of the contralateral CA3. The spike discharge rate during the burst was two or three times higher than that during the period just preceding the burst, but the discharge never occurred in the positive phase of the PSWs. During the initial part of the post-PSW negativity the high firing probability was maintained. Even when the PSW burst was not followed by a detectable post-PSW negativity, the firing probability during the period corresponding to the post-PSW negativity was still significantly higher than the pre-PSW period. It was suggested that the PSW bursts and post-PSW negativity were triggered off in cell-rich areas by diffuse excitatory inputs impinging possibly upon the hippocampal pyramidal cells and subicular principal cells. The rhythmic PSWs may be post-synaptic inhibitory potentials produced on the somata of those cells after activation of recurrent interneuronal circuits.
Animals↗
Modulation during sleep of the cat trigeminal neurons responding to tooth pulp stimulation.
Sleep-induced changes in the trigeminal neuron responses to electrical stimulation of the cat tooth pulp were studied. Two parameters were adopted: One was the evoked spike number at two times the threshold intensity (2 X T response magnitude), which would reveal the level shifting of the neuronal response by the sleep-regulatory system. Another was the rate of change in the response intensity when the stimulus was raised to a level of 0.7 time the arousal threshold during light slow wave sleep (sensitivity gradient), which would reflect the influences of the pain-modulatory system driven by strong noxious inputs. It was found that during sleep the two indexes tended to show a correlated change; the neurons which came to have a greater 2 X T response magnitude tended to have a smaller sensitivity gradient than during wakefulness, and vice versa. It was suggested that two contrasting populations of tooth pulp neurons might be differentiated, and that the sleep-regulatory system and the pain-modulatory system would have differential but correlated controls over these two kinds of neurons.
Animals↗
Histopathologic investigation of a case of meningioangiomatosis not associated with von Recklinghausen's disease.
A case of meningioangiomatosis not associated with von Recklinghausen's disease is reported. Microscopically, irregularly branched blood vessels extending into the gray matter from the meningeal surface are surrounded by a concentric arrangement of proliferating spindle-formed cells. Ultrastructurally these proliferating cells are composed of elongated heterochromatin-rich nuclei and slender cytoplasm-containing microfilaments, occasionally associated with desmosomal junctions and basal laminalike structures. Judging from these findings, together with a negative immune reaction for S-100 protein, the histogenesis of these proliferating cells is most probably meningothelial in origin.
Adult↗
Mode of action of chlorpromazine (CPZ) blockage on 13,14-dihydroprostaglandin F2-alpha formation in rat ovary.
The mode of action of the inhibitory effect of CPZ on 13,14-dihydroprostaglandin F2-alpha (13,14H2-PGF2-alpha) formation in rat ovary was examined. The inhibition of 13,14H2-PGF2-alpha formation and of ovulation induced by a proestrus were completely recovered by an injection of hCG (25 IU/rat) or LH-RH (500 ng/rat) at 15:00 on the same day. 13,14H2-PGF2-alpha formation and ovulation were not inhibited by a single injection of prolactin (PRL:6 IU/rat) at 13:00 on the day of proestrus. Repeated injection of PRL inhibited cyclic ovulation and 13,14H2-PGF2-alpha formation. The estrus cycle of PRL treated animals showed a continuous state of diestrus. Although 13,14H2-PGF2-alpha formation and ovulation were inhibited by the repeated injection of CPZ, the repeated-simultaneous injection of CPZ and bromocriptine at 10:00 once a day for 3 days from the first day of diestrus partly restored both and entirely reversed the suppression of the cyclic-changes in the in the vaginal smear pattern. These results indicate that the inhibition of 13,14H2-PGF2-alpha formation induced by a single injection of CPZ probably occurs via the suppression of LH-RH release from the hypothalamus, whereas PRL secretion may participate in the inhibitory effects of repeated injections of CPZ.
Animals↗
Purification and properties of dimethylsulfoxide reductase containing a molybdenum cofactor from a photodenitrifier, Rhodopseudomonas sphaeroides f.s. denitrificans.
Dimethylsulfoxide (DMSO) reductase was purified to electrophoretic homogeneity from the periplasmic fraction of a photodenitrifier, Rhodopseudomonas sphaeroides f.s. denitrificans. The enzyme had a molecular weight of 82,000 and had no subunit. It contained 1 mol of molybdenum per mol of enzyme, but iron and acid-labile sulfur were not present. The UV-visible spectrum showed only one absorption maximum at 280 nm. Denaturation of the enzyme released a molybdopterin cofactor, the fluorescence spectra of which were almost the same as those of a form B derivative of molybdopterin found in formate dehydrogenase. The Km value for DMSO was 15 microM, which was much lower than that for trimethylamin-N-oxide (TMAO), whereas Vmax with TMAO was larger than that with DMSO.
Amino Acids↗
Mechanism of haemolysis by Vibrio vulnificus haemolysin.
The haemolytic action of Vibrio vulnificus haemolysin (VVH) was compared to that of streptolysin O (SLO). Both were cholesterol-binding haemolysins, but differed in the release of haemoglobin (Hb). In the first step of haemolysis, the haemolysins were temperature-independently bound to the cholesterol site on the target erythrocyte membrane. This was followed by the rapid release of K+, which is an intra-erythrocyte marker. Hb was then released, in different ways. In the case of VVH, Hb was released slowly after a relatively long lag, whereas with SLO, Hb was released as rapidly as K+. Haemolysis by VVH was inhibited by the addition of 30 mM-dextran 4 (mean Mr 4000), which is considered to be an effective colloid-osmotic protectant. The results therefore indicated that haemolysis by VVH (like that by Escherichia coli alpha-haemolysin and Staphylococcus aureus alpha-toxin) was caused by a colloid-osmotic mechanism. Both K+ and Hb release caused by VVH proceeded temperature-dependently, and the membrane fluidity of liposomes prepared with lipids extracted from sheep red blood cell membranes increased above 20 degrees C. These results suggest that the temperature-dependence of the haemolysis by VVH is due to the requirement for an increase in the membrane fluidity during the formation of a transmembrane pore.
Hemoglobins↗
New tetracycline resistance determinant on R plasmids from Vibrio anguillarum.
Two classes of tetracycline resistance determinants on R plasmids were detected in Vibrio anguillarum strains isolated from ayu (sweat fish; Plecoglossus altivelis) farms in Japan. Tetracycline resistance genes categorized as class B were prevalent from 1973 to 1977; however, a new tetracycline resistance gene, which was not classified into tetracycline resistance determinant class A, B, C, or D, has been prevalent since 1981.
Chromosome Mapping↗
Induction of neurite formation in PC12 cells by microinjection of proto-oncogenic Ha-ras protein preincubated with guanosine-5'-O-(3-thiotriphosphate).
Rat pheochromocytoma (PC12) cells differentiate to neuronal cells in response to nerve growth factor. It has been shown that microinjection of oncogenic but not proto-oncogenic p21 protein induces morphological differentiation in PC12 cells (D. Bar-Sagi and J. R. Feramisco, Cell 42:841-848, 1985). In this paper we describe a recombinant human proto-oncogenic Ha-ras protein which can effectively induce neurite extension of PC12 cells when microinjected as a complex with guanosine-5'-O-(3-thiotriphosphate). The protein was found to be less effective when complexed with GTP. On the other hand, an oncogenic ras protein coinjected with guanosine-5'-O-(2-thiodiphosphate) was entirely inactive. These results indicate that the binary p21-GTP complex, but not the p21-GDP complex, is effective in inducing differentiation in PC12 cells, irrespective of the oncogenic or the proto-oncogenic protein.
Adrenal Gland Neoplasms↗
Neutralizing monoclonal antibody against ras oncogene product p21 which impairs guanine nucleotide exchange.
The neutralizing monoclonal antibody Y13-259 severely hampers the nucleotide exchange reaction between p21-bound and exogenous guanine nucleotides but does not interfere with the association of GDP to p21. These results suggest that the nucleotide exchange reaction is critical for p21 function. Interestingly, the v-ras p21 has a much faster dissociation rate than the p21 of the c-ras proto-oncogene.
Antibodies, Monoclonal↗
Effects of co-administration of monomethylaminoantipyrine and cobaltous chloride on hepatic glutathione level and glutathione-related enzyme activities in rats.
Concurrent administration of monomethylaminoantipyrine (MAA) and CoCl2 caused a significant decrease of hepatic reduced glutathione and oxidized glutathione levels. Furthermore, the increase of glutathione S-transferase activity by combined treatment resulted in the decrease of Se-dependent glutathione peroxidase activity.
Aminopyrine↗
Suppression of pentylenetetrazol-induced seizures by hydralazine associated with 5-hydroxytryptaminergic system in rat brain.
The effects of hydralazine on the central nervous system were studied in rats. Administration of hydralazine (10 mg/kg, i.p.) transiently, but significantly suppressed the seizures elicited by pentylenetetrazol (PTZ). The suppressive actions were potentiated in the animals pretreated with either reserpine or p-chlorophenylalanine, but not alpha-methyltyrosine. Methysergide, an antagonist of 5-hydroxytryptamine (5-HT) receptors, could abolish the effect of hydralazine on the tonic component of the seizures, but unlikely that on the clonic one. Although 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels in the brain were both significantly increased after the administration of hydralazine, the increased levels of 5-HIAA reached the peak level earlier than those of 5-HT did. In 5-HT turnover, hydralazine did not change the 5-HT synthesis rate, but the drug inhibited the elimination of 5-HIAA from the brain. The accumulation of 5-HIAA after the inhibition of the acid transport system by probenecid was transiently, but significantly increased in the animals treated with hydralazine. The potency of the suppressive effects of hydralazine on PTZ-induced seizures was in parallel with the rate of 5-HIAA formation in the brain. These results suggest that hydralazine might antagonize the PTZ-induced seizures at least partly by modulating the activation in the central 5-HT-ergic system.
Animals↗
Contribution of isosorbide-5-mononitrate, a major metabolite of isosorbide dinitrate (ISDN), to the hemodynamic effect of ISDN administered orally in conscious dogs.
This study was designed to determine the extent, to which isosorbide-5-mononitrate (5-ISMN) contributes to the hemodynamic effect of isosorbide dinitrate (ISDN) in conscious dogs. Test drugs (ISDN or 5-ISMN) were given orally. Either ISDN or 5-ISMN produced a decrease in blood pressure dose-dependently, the decrease in pulse pressure being specific; the pattern of blood pressure change induced by ISDN or 5-ISMN was different from that induced by nifedipine or prazosin. The effect of ISDN (2 mg/kg) was almost equivalent to that of 5-ISMN (4 mg/kg) and the effect of ISDN (4 mg/kg) to that of 5-ISMN (8 mg/kg). After administration of ISDN, both ISDN and 5-ISMN appeared in the plasma, and the effect of ISDN well-correlated with the increase in the plasma concentration of 5-ISMN. Contribution of 5-ISMN to the effect of ISDN was estimated to be about 30% from the value of the plasma concentration of 5-ISMN at 3 to 4 hr after administration, when the maximal response to ISDN occurred. Based on the data of the area under the plasma concentration curve of 5-ISMN (from 0 to 10 hr after administration), the fraction of biotransformation to 5-ISMN from ISDN was calculated to be 73.6 to 76.6% (based on moles). Because the ability of 5-ISMN to decrease pulse pressure was about 1/2 (or 41% based on moles) of that of ISDN, the contribution of 5-ISMN to the effect of ISDN was estimated to be about 30% in total, the value being similar with that estimated at 3 to 4 hr after administration.
Administration, Oral↗
Simultaneous recordings of calcium signals and mechanical activity using fluorescent dye fura 2 in isolated strips of vascular smooth muscle.
In rat aortic strips loaded with a Ca2+ indicator, fura 2, the Ca2+ signal and contractile tension were simultaneously recorded. On the addition of high K+ or noradrenaline, the 500 nm fluorescence produced by excitation at 340 nm increased and that produced by excitation at 380 nm decreased. EGTA decreased the 340 nm fluorescence and increased the 380 nm fluorescence in resting and stimulated muscles. Tension changes were always preceded by fluorescent changes.
Animals↗
[A case of aortitis syndrome initially presenting with symptoms of the pulmonary infarction].
Explore the source record for details and available documents.
Adult↗
[Histopathological investigation of meningioangiomatosis. Case report].
Explore the source record for details and available documents.
Adult↗