Biomedical subjects

K Inomata

Publications and source records attributed to K Inomata.

At least 55 records · Page 3Linked to original sources

PubMed1993

Teratogenic effects of triethylene tetramine dihydrochloride on the mouse brain.

The teratogenic effects of triethylene tetramine dihydrochloride (Trien-2HCl) on fetal mouse brain were studied on gestational day 19. Trien-2HCl was given throughout pregnancy at levels of 0 (control), 3,000, 6,000, or 12,000 mg/liter as drinking water, ad libitum. Mean litter size and live fetus per dam at birth were not significantly different among the four groups. The frequency of gross brain abnormalities in live fetus at birth such as hemorrhages, delayed ossification in cranium, hydrocephaly, exencephaly, and microcephaly increased with increasing levels of the drug. Microscopically, disorganization of neuronal cell layers, spongiform changes in white matter, and reduced myelin development were noted in the coronally sectioned cerebrum from Trien-2HCl-treated fetus. These abnormal findings increased dose-dependently in regard to the extent and severity at the levels of 6,000 and 12,000 mg/liter. No such changes were observed in the cerebrum of controls. These results suggest that microscopic changes in fetal brain caused by Trien-2HCl may be in part similar to those in brindled mutant mouse. Special attention should be paid to the developing fetal brain when Trien-2HCl is used during pregnancy.

Animals↗

PubMed1992

An oxidized analog of alpha-human atrial natriuretic polypeptide is a selective agonist for the atrial-natriuretic-polypeptide clearance receptor which lacks a guanylate cyclase.

The differences in biological functions between alpha-human atrial natriuretic polypeptide (alpha-hANP) and its oxidized analog, MetSO-alpha-hANP, have been investigated. Analysis of the ANP receptor subtypes by affinity labeling has shown that a bovine pulmonary aortic endothelial cell line (CPAE cells) primarily expresses ANP-R1 (R, receptor) coupled to particulate guanylate cyclase, while Hela cells from human cervical carcinoma predominantly express ANP-R2, which lacks a guanylate cyclase. alpha-hANP could bind to both ANP receptor subtypes with high affinity, while MetSO-alpha-hANP showed more selective binding to ANP-R2 than to ANP-R1. The activity of MetSO-alpha-hANP for stimulation of guanylate cyclase coupled to ANP-R1 was about 520-fold less than that of alpha-hANP (median effective dose = 2.5 nM for alpha-hANP, 1.3 microM for MetSO-alpha-hANP), indicating that MetSO-alpha-hANP was a partial agonist for this receptor. While this oxidized analog could inhibit the cAMP production through ANP-R2, with 0.15 times the activity of alpha-hANP (median concentration = 0.31 nM for alpha-hANP, 2.0 nM for MetSO-alpha-hANP). In in vivo studies, the diuretic activity of MetSO-alpha-hANP was 25-100-fold less than that of alpha-hANP. In addition, MetSO-alpha-hANP could potentiate the diuretic activity of alpha-hANP that was also caused by C-ANF4-23, a specific agonist for ANP-R2. These results demonstrate that MetSO-alpha-hANP can act as an agonist more selective for ANP-R2 than for ANP-R1, both in vivo and in vitro. The relationship between receptor selectivities and the conformation of alpha-hANP or MetSO-alpha-hANP was also discussed.

Affinity Labels↗

PubMed1991

Enzyme-cytochemical study of small ganglion cells in experimental thiamine deficiency: concerning the pain mechanism.

In an effort to clarify the mechanism of pain accompanying thiamine deficiency, thiamine monophosphatase (TMPase) activity was demonstrated, by means of electron microscopic cytochemistry, in small ganglion cells in pyrithiamine-treated thiamine-deficient rats. TMPase activity was seen to be present in the reticular part of the Golgi complex and vesicle-like bodies around the trans side of the Golgi complex. By the 10th day after the initial pyrithiamine treatment, a significant increase in the number of TMPase-positive vesicle-like body was observed. These results indicate that thiamine deficiency causes a disturbance in the transportation and/or production of TMPase, which is an integral part of the synaptic transmission of the nociception impulses.

Animals↗

PubMed1991

Diketopiperazine-mediated peptide formation in aqueous solution. II. Catalytic effect of phosphate.

The previous paper (I) reported that DKP (glycine anhydride) spontaneously reacts with glycine (Gly) or oligoglycines (Glyn) to produce longer oligoglycines (Glyn+2). This paper presents that phosphate catalyzes the condensation reaction quite effectively. Formation of Gly4 from DKP (0.1 M) and Gly2 (0.1 M) in phosphate solution of various concentrations was investigated at a neutral pH at 41 degrees C. The yields of Gly4 increased almost linearly with the concentration of phosphate from 0.06 M to 0.24 M. The yield in 0.24 M phosphate solution was approximately one hundred times as high as that in the absence of the phosphate, whereas in the case of Gly3 formation from DKP and Gly the effect of the phosphate was of ten times lower than in the former case. Orthophosphate was the most effective catalyst among the various kind of chemicals tried in the present investigation including polyphosphates.

Diketopiperazines↗

PubMed1991

Fetal alcohol effects: decreased synaptic formations in the field CA3 of fetal hippocampus.

The effects of prenatal ethanol exposure on the synaptic formation in the field CA3 of the hippocampus of fetal rats have been investigated on gestational day 21. Significantly decreased number of synaptic junctions was observed in the fetus showing decreasing cerebral weight either with or without decreasing body weight. The administration of 0.01% zinc with ethanol or 0.02% alpha-tocopherol acetate with ethanol during pregnancy resulted in an increased cerebral weight, but did not result in an increased synaptic formation compared to ethanol alone. This result indicates that one of the most vulnerable factors in rat fetus exposed to ethanol in utero is the synaptic formation in the hippocampus. In conclusion, ethanol exposure in utero during a period of brain development roughly equivalent to the first and second human trimesters can produce consistent dysforming effect of synapses and may be associated with the functional impairement of the central nervous system in the fetal alcohol effects.

Animals↗

PubMed1991

Effects of low-power gallium aluminium arsenide diode laser irradiation on the development of synapses in the neonatal rat hippocampus.

The effect of low-power gallium aluminium arsenide diode laser irradiation on the development of synapses was studied in the radiatum layer and the lacunosum-molecular layer of field CA3 of the neonatal rat hippocampus. Neonatal rats were irradiated with a low-power diode laser (830 nm, 60 mW) at two points located above the hippocampi, for 15 s, respectively, twice per day from birth (day 1) to day 5. The mean body weights of the laser-irradiated animals were found to be lower than those of the control animals, the deficit at day 20 being 22.6%. Moreover, the density of synaptic junctions stained by ethanolic phosphotungstic acid per unit area of the radiatum layer and the lacunosum-molecular layer of the neonatal rat hippocampus was significantly reduced at day 20. It was suggested that the low-power diode laser irradiation affected the development of synapses in the neonatal rat brain.

Age Factors↗

PubMed1990

Diketopiperazine-mediated peptide formation in aqueous solution.

Though diketopiperazines (DKP) are formed in most experiments concerning the prebiotic peptide formation, the molecules have not been paid attention in the studies of chemical evolution. We have found that triglycine, tetraglycine or pentaglycine are formed in aqueous solution of glycine anhydride (DKP) and glycine, diglycine or triglycine, respectively. A reaction of alanine with DKP resulted in the formation of glycylglycylalanine under the same conditions. These results indicate that the formation of the peptide bonds proceeds through the nucleophilic attack of an amino group of the amino acids or the oligoglycines on the DKP accompanied by the ring-opening. The formation of glycine anhydride, di-, tri- and tetraglycine was also observed in a mixed aqueous solution of urea and glycine in an open system to allow the evaporation of ammonia. A probable pathway is proposed for prebiotic peptide formation through diketopiperazine on the primitive Earth.

Amino Acid Sequence↗

PubMed1990

Prebiotic synthesis of orotic acid parallel to the biosynthetic pathway.

By heating an aqueous solution of aspartic acid and urea, carbamylaspartic acid is first formed and then the molecule is cyclized to dihydroorotic acid (DHO) with loss of water. Irradiation of an aqueous solution of DHO with a tungsten lamp yields orotic acid by photo-dehydrogenation of the molecule. This pathway of orotic acid formation is quite similar to that of biosynthesis of the molecule.

Aspartic Acid↗

PubMed1990

Abnormal movements in brindled mutant mouse heterozygotes: as related to the development of their offspring--biochemical and morphological studies.

As a possible preventive measure for brain dysfunction in Menkes disease, prenatal treatment by maternal administration of zinc, vitamin E and copper was examined in brindled mutant mice. During pregnancy and lactation, female heterozygous mice received 20 ppm zinc or 0.004% alpha-tocopherol acetate (vitamin E) throughout and 6 ppm copper from gestational day 13 in the drinking fluid, ad libitum. The maternal administration of zinc and vitamin E, as antioxidants, or copper resulted in decreased fetal and neonatal death of offspring, especially those of hemizygous males, as compared with the administration of water only. When offspring did not grow, maternal abnormal movements, which comprised rotatory movements of high speed with tremor and ataxia, were frequently observed. In the heterozygotes with abnormal movements, the level of lipid peroxidation in cerebrum and the concentration of copper in kidney were much higher than those in the heterozygotes with normal movement. Morphologically, in cerebellum of the heterozygotes with abnormal movements, the loss of Purkinje cells, abundance of lipofuscin granules and abnormal mitochondria or degenerative bodies of high electron density were frequently observed, as compared with heterozygotes with normal movement. These findings suggest that the development of hemizygous male mice may be influenced by both copper and oxygen radical metabolism.

Animals↗

PubMed1990

Increased flap survival after sensory denervation with capsaicin accompanied by delay.

The effect of capsaicin, combined with delayed surgical procedures, was studied in adult rats. After denervation of the experimental subjects' cutaneous nerves with capsaicin, the time required for the flaps to become completely necrotic was prolonged; when accompanied by delayed flap raising for a period of up to eight weeks, the flap survival rate was increased. Although there were no significant differences in flap survival between the control and the capsaicin animals undergoing flap raising with no delay, increased vascularity and flap survival were confirmed in capsaicin animals in whom procedures had been delayed. Maximum flap survival was found in capsaicin animals undergoing a six-week delay in the procedures. These results suggest that sensory nerves play an important role in flap survival, perhaps in the areas of flap vascular supply and tension control of the A-V shunt in the microcirculation of a flap.

Animals↗

PubMed1990

Correlation of the hypo-osmotic swelling test, semen score and the zona-free hamster egg penetration assay in humans.

The correlation between the hypo-osmotic swelling test, the modified Eliasson score for human semen analysis and the hamster egg penetration assay was examined. The results showed a weak but significant correlation between the group of subjects with swelling rates below 50% and the above 80% group. These groups showed hamster egg penetration assay rates of 9 +/- 14% and 39 +/- 29%, respectively (P less than 0.035). A significant correlation was also found between modified Eliasson scores (17 +/- 10 and 5 +/- 7, respectively) and swelling rates below 50% and above 70% (P less than 0.001). These results suggest that spermatozoa showing a low swelling rate have a poor fertilizing capacity. Therefore, the swelling tests and analysis of the patients semen can be used to discriminate sperm quality.

Acrosome↗

PubMed1990

Stereoscopic observation of enzyme distribution in lowicryl K4M-embedded specimens by conventional electron microscopy.

The present investigation was undertaken to explore the value of the Lowicryl K4M embedding technique for enzyme histochemical examination of semi-thin sections. The low-temperature embedding procedure with Lowicryl K4M was found to provide favorable conditions for preservation of enzyme activity in tissue samples. We tested the histological effects of various fixatives; the best results were obtained using 4% paraformaldehyde when testing for AcPase, AlPase, TPPase, and Mg-ATPase in the dorsal root ganglion. The three-dimensional cellular fine structure could be clearly seen in stereo pair pictures under stereoscopy.

Acid Phosphatase↗

PubMed1990

[Changes in the ions and protein concentrations and flow rate of parotid saliva by tongue sour stimulation].

Changes in the concentrations of ions (K+, Cl-, Na+), total protein, amylase activity and flow rate of parotid saliva were observed by tongue stimulation with 3% tartaric acid various intervals in a subject after about one hour rest. The results may be summarized as follows: 1) After about one hour rest state, the values of each item were K+: 42-56 mEq/l, Cl-: 8-28 mEq/l, Na+: 1-10 mEq/l, total protein: 5.7-11 mg/ml, amylase activity: 2-6.5 x 10(3)U/ml and flow rate: 0.03-0.05 ml/min. 2) The changes were classified into two groups based on the recovery from peak to rest values. One group showed short recovery times (Cl-: 20 min., Na+: 8 min. and flow rate: 2 min.) and the other group had rather longer recovery times (K+: 40 min., total protein: 55 min. and amylase activity: 40 min.). The differences between these two groups were clear when the stimulus intervals were 30 sec. to 5 min. 3) When the tongue was stimulated every 15 sec. all items showed first responses, after that, the all values except the flow rate remained unchanged. 4) Different values in ions and protein concentrations and amylase activity were observed when the flow rate was similar before and after stimulation. 5) The recovery time of the responses of protein concentration and amylase activity to stimulation was about one hour, and a rest period of more than one hour is necessary to analyze the concentration of total protein and amylase activity in parotid saliva.

Amylases↗

PubMed1990

[Changes in Po2, Pco2, pH, and HCO3 concentration and flow rates in human parotid saliva by tongue sour stimulation at various intervals].

The PO2, PCO2, pH, and HCO3- concentration and flow rates of parotid saliva were observed by tongue stimulation with 3% tartaric acid at various intervals in a human subject after about a one hour rest. The PO2, PCO2, pH, and HCO3- concentrations in parotid saliva were measured with a Blood Gas Analyzer System. The results are summarized as follows: 1) The mean PO2 and PCO2 of parotid saliva immediately before tongue stimulation were about 40 mmHg (range 33-44 mmHg) and 45 mmHg (41-48). There values were similar to those of venous blood. 2) PO2 increased to about 50 mmHg (46-54) 5 to 10 sec. after stimulation, and then 3 to 8 min. later, it decreased to a minimum value of about 28 mmHg (26-29) before returning to the resting level 15 min. after stimulation, when the intervals between stimulations were longer than 2 min., similar changes in PO2 were observed, whereas stimulations every 30 sec. or 1 min. had no effect on PO2. 3) PCO2 increased to about 98 mmHg (85-120) from the resting level of 45 mmHg (41-48) 5 to 10 sec. after stimulation, and returned to the resting level 1 min. after stimulation. When the intervals between stimulations were shorter than 20 min., the peak value of PCO2 by the first stimulation was higher than those induced by the following stimulations. When the interval was 30 sec. or 1 min., only the peak after the first stimulation was observed. 4) The pH of parotid saliva was about 7.4 (7.35-7.5) 30 to 50 sec. after stimulation, and it decreased below 6.5 about 12 min. after stimulation. When the interval between stimulations was 5 min., the pH of the parotid saliva after stimulation was always above 6.5. When the interval between stimulations was 1 min. or 30 sec., it remained at about 7.5. 5) The HCO3- concentration in parotid saliva depends almost exclusively on the pH when Pco2 remained unchanged. When Pco2 was high, however, the HCO3- concentration was affected by the change in Pco2. 6) There was no relationship between changes in the flow rate of parotid saliva and Po2, Pco2, pH, and the HCO3- concentration. Particularly, when the interval between stimulations was shorter than 5 min., the changes in flow rate had no effect on Po2, Pco2, pH, and the HCO3- concentration.

Blood Gas Analysis↗

PubMed1990

[Effect of bite force on parotid secretion in human].

To determine the physiological roles of periodontal mechanoreceptors in parotid salivary secretion, we studied the effects of strength and frequency of unilateral bites on the salivary secretion from both sides of human parotid glands. Parotid saliva was collected bilaterally via modified Lashley cups, and the flow rate of parotid saliva was measured with a device using a strain gauge. The bite force was monitored with a pressure transducer. In the first experiment, subjects were constantly occluded for one minute at 80 strokes per minute at strengths of 5, 10, and 20 kg. In the second experiment, subjects were occluded for one minute at a constant force of 10 kg at frequencies of 20, 40, 80, and 120 strokes per minute, or subjects were continuously clenching for one minute. The flow rate of parotid saliva gradually increased with increasing bite strength, while it gradually decreased with increasing bite frequency. In unilateral bites, the salivary flow rate of the ipsilateral parotid gland was greater than that of contralateral parotid gland, at any strength and frequency. These results suggest that periodontal mechanoreceptors are involved in parotid salivary reflexes initiated by bite force stimuli.

Bite Force↗

PubMed1990

[Effects of addition of calcium phosphates on the properties of gypsum].

Calcium hydrogen phosphate (CHP), calcium hydrogen phosphate dihydrate (CHPD) and calcium sulfate dihydrate (gypsum) crystals were added to calcium sulfate hemihydrate as gypsum model materials for improvement of the mechanical properties. The compressive and the bending strength of the hardened mixture were improved by the addition of CHPD, while the addition of CHP and gypsum crystals had no effect. The setting time was markedly reduced by the addition of CHPD, but remarkably increased in the case of CHP crystals. On the other hand, the setting expansion was decreased by the addition of CHP and CHPD crystals. Based on the observation of the surface profile of the calcium sulfate hemihydrate set in contact with glass, and scanning electron microscopy (SEM) of the fractured surface of the hardened mixture, the surface roughness was markedly decreased by the addition of CHPD. When the crystals were added to the metastable solution of calcium sulfate supersaturated with respect to gypsum, the presence of gypsum crystals deposited on the CHPD surface was confirmed by atomic absorption analysis, fourier transform infrared spectroscopy. SEM and electron X-ray microanalysis. Therefore, epitaxial growth of gypsum occurred on the CHPD surface and the addition of CHPD improved the mechanical properties of the gypsum materials.

Calcium Phosphates↗

PubMed1990

Ultracytochemical demonstration of Ca2(+)-ATPase activity in the rat saphenous artery and its innervated nerve terminal.

The localization of Ca2(+)-ATPase activity was ultracytochemically investigated in the rat saphenous artery and nerve terminals innervating the saphenous artery using a lead citrate method devised by Ando et al. (1981). Intense reaction products in the saphenous arterial endothelial cells were observed inside the caveolae and vesicles along the luminal and abluminal sides. In addition, Ca2(+)-ATPase activity was observed on the external side of the luminal, abluminal and lateral plasma membrane, and the outer membrane of mitochondria. In the smooth muscle cells, intense Ca2(+)-ATPase activity on the inside of caveolae and vesicles was observed, comparing in intensity with that on the plasma membrane of smooth muscle cells. In the nerve terminals innervating the saphenous artery, Ca2(+)-ATPase activity was demonstrated on the plasma membrane of the nerve terminal-Schwann cell interface, the axolemma of unmyelinated axons and the plasma membrane of Schwann cells. It is suggested from the above ultracytochemical results that Ca2(+)-ATPase activity plays an important role in the contraction and relaxation of the saphenous artery, and in the neurotransmitter release.

Animals↗

PubMed1990

Morphological studies of bradykinin-treatments on the rat trigeminal sensory neuron.

Subcutaneous injections of bradykinin to the rat trigeminal region over 4 days produced a significant increase in the number of mitochondria in the small trigeminal ganglion cells and the central terminals of unmyelinated fibers in the spinal trigeminal nucleus. In the large trigeminal ganglion cells, no significant change in the number of mitochondria was observed. These results seem to demonstrate that bradykinin stimulates unmyelinated nerve and increases its energy consumption.

Animals↗