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Biomedical subjects

K Takeuchi

Publications and source records attributed to K Takeuchi.

At least 1,279 records · Page 71Linked to original sources
PubMed1983

[Effects of SM powder, a combined herbal preparation for stomach diseases, on gastric secretion and acute gastro-duodenal lesions in rats].

One gram of SM powder consists of 167.8 mg of Coptidis Rhizoma Pulveratum, 250 mg of Cinnamomi Cortex Pulveratus, 67.1 mg of Foeniculi Fractus Pulveratus, 33.6 mg of Caryophylli FLos Pulveratus, 82.1 mg of Zingiberis Rhizoma Pulveratus, 3.4 mg of Zanthoxyli Fructus Pulveratus, and 396 mg of Glycyrrhizae Radix Pulberata. SM powder (2 g/kg, i.d.) significantly inhibited gastric secretion in pylorus-ligated rats and the development of Shay ulcers and indomethacin-induced gastric lesions. The mechanism of the anti-lesion activity of SM powder appears to be due to its antisecretory effect. SM powder also markedly inhibited ethanol- or NaOH-induced gastric lesions at doses (30 or 100 mg/kg) which had little effect on gastric secretion. SM powder appears to have a cytoprotective activity which is unrelated to endogenous prostaglandins. However, SM powder had no effect on water-immersion stress- or aspirin-induced gastric lesions and mepirizole-induced duodenal ulcers. Gentiana Radix Pulverata, used as a reference stomatic, had also an antisecretory effect and anti-lesion activity on Shay ulcers, aspirin-, ethanol- and NaOH-induced gastric lesions. However, it had no effect on water-immersion stress- or indomethacin-induced gastric lesions and mepirizole-induced duodenal ulcers.

Animals↗
PubMed1982

Characterization of the interaction between gastrin and its receptor in rat oxyntic gland mucosa.

A gastrin receptor, identified in crude membrane preparations of rat oxyntic gland mucosa, has an equilibrium dissociation constant (Kd) of approx. 4 . 10(-10)M and a binding capacity of 4 fmol/mg protein. The binding capacity was significantly lower after 2 days of fasting, parallel with a significant drop in serum gastrin levels; there was no change in Kd. In order to verify Scatchard analysis and to determine if there was a coincident alteration in the association (k+1) and dissociation (k-1) rates in the fasted rat, a kinetics study was performed. Under our conditions, there appeared to be a single set of binding sites and the binding reaction obeyed first-order dissociation, and second-order association rate kinetics. Second-order association rate kinetics were validated by demonstrating the independence of the rate constants when there were alterations in the concentrations of reactants. The average k+1 was determined to be 2 . 10(6) M-1 . s-1. The average k-1 was determined to be 1 . 10(-3) s-1. There was no significant change in the k+1 and k-1 in fed and fasted rats. Fasting decreased the number of gastrin receptors without altering the affinity of the receptor for the hormone.

Animals↗
PubMed1982

In vitro characterization of the fibroin gene promoter by the use of single-base substitution mutants.

A highly efficient method for segment-directed mutagenesis has been developed. The method relies on the deamination by sodium nitrite of the bases in the separated strands of a small DNA restriction fragment. The mutagen-treated strands produce transition mutations by the following sequence: (i) hybridization with the complementary strand of the wild-type DNA that had been cloned into a phage fl vector, (ii) repair synthesis in vitro, and (iii) transfection of Escherichia coli. Using this method, we have isolated 14 single-point mutants within a 31-base-pair stretch of the fibroin gene (from the T-A-T-A box at the nucleotide position -30 to the cap site at +1). In vitro transcription experiments with the HeLa cell or the silk gland cell extract show that single-base transitions at the T-A-T-A box (T to C at -30, A to G at -29, and T to C at -28) and at the -20 region (G to A at -21, T to C at -20, and A to G at -17) result in decreased promoter activities, whereas those at the cap site and the -10 regions have no effect. The initiation site of transcription is the same for five "down" (reduced activity) mutants (T to C at -30, T to C at -28, G to A at -21, T to C at -20, and A to G at -17), the cap site mutant (A to G at +1), and the wild-type genes--position +1. However, the A-to-G transition at -29 (the second base of the T-A-T-A box) induces an additional transcription start from position +4. Functions of the T-A-T-A box and the -20 regions are discussed.

Base Sequence↗
PubMed1982

Differences between smooth and skeletal muscle myosins in their interactions with F-actin.

Myosin and F-actin were prepared from bovine carotid arterial smooth muscle and the properties of the binding of myosin to F-actin were compared with those of the binding of skeletal muscle myosin to F-actin. The following differences were observed between skeletal and smooth muscle myosins. 1. The rate of ATP-induced dissociation of arterial actomyosin was equal to that of hybrid actomyosin reconstituted from arterial myosin and skeletal muscle F-actin, but was much lower than those of skeletal muscle actomyosin and of hybrid actomyosin reconstituted from skeletal muscle myosin and arterial F-actin. 2. The amount of ATP necessary for complete dissociation of arterial actomyosin was 2 mol/mol of myosin, although it is well known that skeletal muscle actomyosin is dissociated completely by the addition of 1 mol ATP per mol of myosin. 3. Arterial actomyosin and hybrid actomyosin reconstituted from arterial myosin and skeletal muscle F-actin did not dissociate upon addition of 0.1 mM PPi, while skeletal muscle actomyosin dissociated completely. 4. In the absence of Mg2+, neither dissociation by ATP nor ATPase [EC 3.6.1.3] activity was observed with arterial actomyosin and hybrid actomyosin reconstituted from arterial myosin and skeletal muscle F-actin. On the other hand, skeletal muscle actomyosin dissociated almost completely upon addition of ATP and showed a considerably high ATPase activity. These observations reveal marked differences between myosins from skeletal and smooth muscles in their binding properties to F-actin.

Actins↗
PubMed1982

Mucosal gastrin receptor. VII. Up- and downregulation.

A series of experiments were performed to examine the long-term upregulation of the gastrin receptor and to explore the possibility of a short-term down regulation with regard to the time course of the trophic action of gastrin. Vagotomy or fasting was used to examine upregulation. Elevated serum gastrin levels observed postvagotomy are accompanied by an increase in gastrin binding capacity. Conversely, fasting caused a decline in serum gastrin and receptor levels; refeeding restored both values to normal levels. Cycloheximide was used to study the role of protein synthesis in the upregulation of gastrin receptors in vagotomized and refed rats, and it prevented the rise of gastrin binding capacity to either normal or above-normal values. This indicates that protein synthesis may play an integral part of receptor upregulation. Following the injection of gastrin-17, there was a short-term induction of downregulation. These results coupled with the maximal reduction of gastrin receptor 3 h after cycloheximide injection indicate that the gastrin receptor has a short half-life. Following the gastrin receptor interaction, the cellular response occurs at discrete periods and manifests itself as both down- and upregulation.

Animals↗
PubMed1982

Mechanism of luminal alkalinization by bullfrog fundic mucosa.

Metiamide-inhibited fundic mucosa of bullfrog secreted alkali (OH-) at 0.1-0.2 mueq.cm-2.h-1.OH- was abolished by dinitrophenol (DNP) and was decreased significantly by 4,4-didsothiocyano-2,2-disulfonate stilbene (DIDS), anoxia, or HCO3(-)-free nutrient solution. In Na+ solutions, increasing nutrient, [HCO3(-)] augmented OH- and Isc linearly while resistance (R) decreased. No such changes occurred in Na+-free nutrient solution. In all experiments, delta Isc was approximately 12 X delta OH. Replacement of Cl- in the secretory solutions or in the nutrient solutions had no significant influence on OH-. When Na+-free nutrient solutions and Cl--free secretory solutions were present, OH- decreased significantly (P less than 0.01). Increasing nutrient [Cl-] in the absence of secretory Cl- significantly (P less than 0.01) augmented OH- and Isc. In the absence of secretory Cl-, OH- and Isc were linearly related to varying nutrient [Cl-]. In tissues with nutrient solutions on the secretory side and vice versa, apparent OH- was 0.4-0.5 mueq.cm-1.h-1 and was dependent on secretory [HCO3(-)] but was not affected by DNP, DIDS, or replacement of Cl- on secretory or nutrient solutions. We conclude that 1) OH- secretion is dependent on nutrient HCO3(-) and Na+ and oxidative metabolism, 2) endogenous HCO3(-) does not contribute significantly, and 3) adequate tissue Cl- must be present for normal OH-.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1982

Mucosal gastrin receptor. VIII. Sex-related differences in binding.

The purpose of the current study was to determine whether gastrin binding differed between the sexes and, if so, to ascertain the factors responsible. Male and female rats were killed at various times from 15 to 60 days after birth. Binding capacities in male and female rats were equal until puberty. By day 40 there were significantly more receptors present in males than females. Females had 2.4 fmol receptor/mg prot by day 40, and this value remained constant into adulthood. In male rats the number of receptors continued to increase to 4.0 fmol/mg prot at day 60. Castration did not significantly decrease the number of receptors in male rats. Ovariectomy, however, increased the number of receptors in female rats to a value not significantly different from male controls. Ovariectomized females consumed more food and had higher serum gastrin levels. If ovariectomized rats were pair fed to the level of intact females, the number of receptors and serum gastrin levels decreased over those present in ovariectomized rats fed ad libitum but still remained significantly higher than those in intact females. Adrenalectomy of ovariectomized females caused a further increase in receptor number.

Adrenalectomy↗
PubMed1982

Multivariate analysis using a linear discriminant function for predicting the prognosis of congestive heart failure.

Some of cases of congestive heart failure (CHF) are intractable or refractory and respond poorly to conventional treatment. We have examined factors which may influence the clinical course and prognosis. The subjects were 114 hospitalized patients with CHF. Of these, 77 had a good response to treatment and were classified as the curative group (Group C) while the remaining 37 who were difficult to treat, including those with poor prognosis, were designated the refractory group (Group R). Of the various clinical background factors including the findings of laboratory and other examinations, the following 8 variables made a significant contribution to differentiation between the 2 groups: 1) heart rate (X1), 2) hemoglobin content (X2), 3) serum K (X3), 4) serum total protein (X4), 5) A/G (X5), 6) BUN (X6), 7) grade of hepatomegaly (X7), and 8) number of previous CHF episodes (X8). The linear discriminant function represented by the following equation using these 8 variables showed an excellent result in differentiating the 2 groups. Y = - 9.64 - 0.0686X1 + 0.345X2 + 1.351X3 + 1.513X4 + + 1.988X5 - 0.0876X6 - 0.792X7 - 0.737X8. When Y value is over 0, Group C is judged. When Y value is under 0, group R is judged. We concluded that the discriminant equation covering these 8 factors is a useful means of predicting the prognosis in CHF and the response to treatment.

Adult↗
PubMed1982

[Reproduction study of Guanabenz, a new antihypertensive agent (2) - teratological test in rats].

Guanabenz (WY-8678) was given to pregnant rats to examine its effects on dams, their fetuses, and offspring. The drug was administered orally to rats at 15, 5 and 1 mg/kg/day from the 7th days of gestation. The vehicle used was 5%-Arabic Gum at dose level of 5 ml/kg, and a control experiment where only the vehicle was administered was also conducted. The results obtained were as follows. 1. In the observation of the dams, the increase of body weight tended to be repressed in the 15 mg/kg group, and body weight decreased in the 30 mg/kg group. 2. The drug produced decreased spontaneous movement, sedation, and lacrimation of red exudate in dams. 3. Half of the 30 mg/kg group had a resorption, but there were no remarkable effects on length of gestation and nursing in the nursing group. 4. The weight of the thymus decreased dose-dependency. 5. No difference was observed in each group in the number of corpora lutea, the number of resorptions, the number of live fetuses, sex ratio, and mean placental weight of the fetuses. The mean body weight of the fetuses decreased in the 30 and among 15 mg/kg groups. 6. In observation of the fetuses, no difference was observed among groups regarding external and visceral malformations. In the skeletal observation, retardation of ossification of the forelimb and hind limb was observed in the 30 and 15 mg/kg groups, and retardation of ossification of the sternebra was observed in the 30 mg/kg group. 7. In observation of the offspring, the number of implantations, the number of live fetuses, delivery rate, and viability rate decrease in the 30 mg/kg group. No difference was observed among groups as to postnatal development symptoms, the faculties of sensation, and emotion. From these results, it is conducted that Guanabenz has no teratogenic potential in rats and the safe dosage levels seems to be below 5 mg/kg/day.

Abnormalities, Drug-Induced↗
PubMed1982

[Reproduction study of Guanabenz, a new antihypertensive agent (3) - perinatal and postnatal test in rats].

Guanabenz (WY-8678) was given to rats to examine its effects on dams and offspring in terms of influence on postnatal development emotion, learning and reproductive ability. The drug was administered orally to rats at 15, 8, 5, 2 and 1 mg/kg/day from the 17th day of gestation to the 21st post-partum day. The vehicle used was 5%-Arabic Gum at dose level of 5 ml/kg and a control experiment where only vehicle was administered was also conducted. The results obtained were as follows. 1. In observation of the dams, increase in body weight tended to be repressed after administration in the 8 mg/kg group, and in the 15 mg/kg group body weight decreased. Food consumption and water intake tended to be suppressed in the 15 mg/kg group. During nursing, changes of body weight, food consumption and water intake were not influenced by Guanabenz in each group. 2. The drug produced sedation, abnormal walking, decrease in a reflex test and lacrimation of red exudate in dams. 3. In the 15 mg/kg group, the length of gestation was prolonged. Furthermore, abnormal delivery and nursing were observed, and in one-third of dams in the 8 mg/kg group and in all dams of 15 mg/kg group, the still-birth of all offspring was observed. No difference was observed among groups as to the organ weights at weaning. 4. In observation of the offspring, differences were observed in the viability rate and the weaning rate. No difference was observed among groups as to the viability rate, changes of body weight, postnatal development, and behavioral development on the 7th day. No differences were observed in each group regarding emotion, motion, perception and learning. 5. No difference was observed among groups in the reproduction test. As to symptoms seen in gestation, the dams and fetuses were not influenced by dosage of Guanabenz. From these results, the safe dose level seems to be below 5 mg/kg/day.

Animals↗
PubMed1982

[Reproduction study of Guanabenz, a new antihypertensive agent (4) - teratological test in rabbits].

Guanabenz (WY-8678) was given to pregnant rabbits to examine its effects on the dams and their fetuses. The drug was administered orally to rabbits at does of 10, 8, 5 and 1 mg/kg/day from the 6th to 18th days of gestation. The vehicle used was 5%-Arabic Gum at dose level of 10 ml/kg, and a control experiment where only the vehicle was administered was also conducted. The results obtained were as follows. 1. Concerning the effects on the dams, the symptoms of decrease in spontaneous movement and sedation were observed at 10 mg/kg. However, mean body weight, food consumption, and organ weight were not influenced by Guanabenz. 2. In the observation of the fetuses, no difference was observed among groups in the number of corpora lutea, the number of implantations, implantation rate, the number of resorption, the number of dead fetuses, the number of live fetuses, sex ratio, mean body weight of the fetuses, mean body length of the fetuses, and mean placenta weight of the fetuses. 3. No difference was observed among groups regarding external malformations, visceral malformations, skeletal malformations, skeletal variations and degree of ossification in the fetuses. From these results, it is concluded that Guanabenz has no teratogenic potential in pregnant rabbits and on effect no fetuses at doses of 8 mg/kg or lower.

Abnormalities, Drug-Induced↗
PubMed1982

[Reproduction study of Guanabenz, a new antihypertensive agent (1) - fertility test in rats].

Guanabenz (WY-8678) was given to rats to examine its effects on their reproductive ability, dams and their fetuses. The drug was administered orally to rats at 30, 15, and 1 mg/kg/day. The vehicle used was 5%-Arabic Gum at dose level of 5 ml/kg, and a control experiment where only vehicle was administered was also conducted. Male rats were treated for 60 days before mating and the treatment continued through mating. Female rats were treated 14 days before mating and the treatment continued from mating to the 7th day of gestation. The results obtained were as follows. 1. In male rats before mating in the 30, 15, and 5 mg/kg groups, the increase of body weight tended to be suppressed, and decrease of food consumption and increase of water intake were found. In female rats before mating in the 30 and 15 mg/kg groups, increase of body weight tended to be repressed, and decrease of food consumption and increase of water intake were found in each group. 2. In the observation of males and females, the drug induced decrease in spontaneous movement, sedation, lacrimation of red exudate and nebula of the eyeball. 3. In the reproduction test, copulations were confirmed in almost all rats by the second cycle of matings. However, the pregnancy rate tended to decrease a little in the 30 and 15 mg/kg groups. 4. Body weight increase during gestation was not affected by oral administration of 1 mg/kg, but was inhibited dose-dependently by administration of more than 5 mg/kg/day of Guanabenz. Food consumption and water intake tended to increase in drug-treated groups. 5. In the observation of the fetuses, the average number of corpora lutea were decreased in the 15 mg/kg group. The average number of implantations decreased in the 30 and 15 mg/kg groups. The implantation rate decreased in the 30 mg/kg group. No difference was observed in each group on the number of resorptions, the number of live fetuses, and the sex ratio. 6. No difference was observed in each group as to external and visceral malformations. In the skeletal observation, retardation of ossification was observed in the 30 mg/kg group. From these results, it is concluded that Guanabenz shows neither fatal effect nor teratogenic potential on fetuses in rats and the safe dosage level seems to be below 5 mg/kg/day.

Abnormalities, Drug-Induced↗