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Biomedical subjects

K Shimamura

Publications and source records attributed to K Shimamura.

At least 19 recordsLinked to original sources

Invasive thymoma with intracaval growth into the right atrium.

We report an unusual case of invasive thymoma with intracaval growth into the right atrium. Computed tomography and venacavography demonstrated this manner of extension of thymoma. The tumor was completely removed by means of cardiopulmonary bypass after four courses of chemotherapy. Multidisciplinary treatment for invasive thymoma with this growth pattern is thought to be useful.

Aged

E-cadherin expression in a particular subset of sensory neurons.

We found that the dorsal root ganglia (DRG) and trigeminal ganglia of mouse embryos express the E-cadherin cell-cell adhesion molecule and analyzed its expression profile. E-cadherin expression began around Embryonic Day 12 (E12) in these ganglia, thereafter increased, and persisted to the adult stage. This cadherin was expressed by 10 and 30% of DRG neurons in E17 and postnatal animals, respectively, as well as by satellite cells and some Schwann cells. E-cadherin-positive primary sensory fibers terminated only in a narrow region of the dorsal horn of the spinal cord, which was identified as part of lamina II by double-staining for E-cadherin and substance P or somatostatin. This E-cadherin expressing area of the spinal cord extended to part of the trigeminal nucleus in the medulla. These results showed that E-cadherin is expressed in a particular subset of primary sensory neurons which may have specific functional properties. We suggest that this adhesion molecule may play a role in the selective adhesion of sensory neuronal fibers.

Animals

Effects of chronic treatment with SQ29852 on spontaneous smooth muscle tone and endothelium-dependent relaxation in aorta of stroke-prone spontaneously hypertensive rats.

The effects of chronic treatment with SQ29852, an angiotensin-converting enzyme inhibitor, on spontaneous smooth muscle tone and endothelium-dependent relaxation of aorta from stroke-prone spontaneously hypertensive rats (SHRSP) were studied and compared with those of captopril. Endothelium-removed aorta from 16-week-old SHRSP exhibited a high amplitude of spontaneously developed active tension (active tone), whereas no active tone was observed in the preparation from control normotensive Wistar-Kyoto (WKY) rats. Treatment with SQ29852 or captopril at age 5-16 weeks prevented the development of hypertension. No active tone could be detected in the preparation from SQ29852-treated SHRSP. Endothelium-dependent relaxation was markedly reduced in the preparation from nontreated SHRSP compared with WKY rats. Treatment with SQ29852 prevented the impairment of endothelium-dependent relaxation. It was also shown that norepinephrine-induced contraction was markedly depressed in endothelium-intact aorta from SQ29852-treated rats. The effects of SQ29852 were more prominent than those of hydralazine when blood pressure was maintained at similar levels. It was suggested that SQ29852 exerts an action on both vascular smooth muscle and endothelium that is mediated by the inhibition of angiotension-converting enzyme in addition to indirect actions of SQ29852 that are brought about by blood pressure lowering.

Acetylcholine

Oxytocin actions on voltage-dependent ionic channels in pregnant rat uterine smooth muscle cells.

The effects of oxytocin, a uterotonic polypeptide hormone, on the voltage-dependent slow calcium, fast sodium, and potassium channel currents were studied using whole-cell voltage clamp of freshly isolated cells from late pregnant (18-21 day) rat myometrium. The calcium current was rapidly inhibited by oxytocin (about 25% inhibition at 20 nM) in a dose-dependent manner, and this inhibitory effect was completely reversible by washout. However, inhibition was not observed when barium was used as the charge carrier. Sodium current and potassium current were not modified by oxytocin, thus sodium and potassium currents may not play important roles in oxytocin-induced augmentation of uterine contraction. It is concluded that oxytocin stimulates uterine contraction by mechanisms other than augmentation of the voltage-dependent calcium current, e.g., by release of Ca from sarcoplasmic reticulum (by inositol triphosphate) or by activation of a receptor-operated Ca channel. The inhibition of the slow calcium current may be induced by the elevation of [Ca]i.

Animals

Potentiation of twitch contraction in guinea pig ureter by sodium vanadate.

The effect of sodium vanadate on action potential and twitch contraction of guinea pig ureter was studied and compared with that of ouabain, elevated K+, low temperature, and a Ca agonist (BAY K 8644), which can be expected to exert certain comparative effects. Sodium vanadate markedly potentiated twitch contraction. Potentiation by vanadate was associated with marked prolongation of relaxation time. Sodium vanadate caused only slight depolarization of the membrane but marked changes in action potential. The duration of action potential was prolonged and the number of oscillatory spike potentials increased. These effects were different from those of other treatments. It is concluded that prolongation of action potential and the increase in the number of spikes are the main cause of potentiation of twitch contraction by sodium vanadate. In addition, inhibition of Ca pump activity of the smooth muscle membrane system by vanadate might also be involved in potentiation of twitch contraction.

Action Potentials

Inhibition of nasopharyngeal colonization of Hemophilus influenzae by oral immunization.

Nontypeable Hemophilus influenzae organisms were inoculated into the nasopharynx of BALB/c mice immunized by oral administration of formalin-killed bacteria. Salivary antibodies and the colonization of H influenzae in the nasopharynx were investigated in order to clarify the effect of oral immunization. Salivary immunoglobulin A antibody titers against H influenzae were significantly increased by oral immunization, but salivary immunoglobulin G antibody titers were not. The bacteria inoculated into the nasopharynx were more rapidly eliminated in immunized mice than in control mice. The results suggest that oral immunization might be useful in preventing otitis media with effusion by inhibiting the colonization of the nasopharynx by pathogenic bacteria.

Administration, Oral

Local and transient expression of E-cadherin involved in mouse embryonic brain morphogenesis.

We found that E-cadherin (uvomorulin) is transiently expressed in restricted regions of the metencephalon, mesencephalon and diencephalon of mouse embryonic brain. This expression first occurred in parts of the mesencephalon and diencephalon at around E9.5, and subsequently extended to the primordia of cerebellum, the dorsal midline of mesencephalon and some other regions of the embryonic brain. These E-cadherin expressions ceased by E15 except at the dorsal midline. Immunohistological analyses showed that E-cadherin-positive cells are radially arranged in the neural tube and the E-cadherin-positive regions are sharply demarcated from E-cadherin-negative regions. Axons extending from some of the E-cadherin-positive regions also expressed this molecule. When embryonic brains were dissociated into single cells and cultured as monolayers, E-cadherin-positive cells formed clusters that were segregated from E-cadherin-negative cells. E9.5 brain fragments containing metencephalon and mesencephalon were isolated, explanted on Nucleopore filters and cultured in the absence or presence of antibodies to E-cadherin. This antibody treatment removed most of the E-cadherin molecules from the explants and consequently affected their growth pattern. To analyze cellular events induced by the antibody treatment, we stained these explants with an antiserum to En whose distribution was found to overlap in part with that of E-cadherin and found that the pattern of En staining was altered by the anti-E-cadherin antibody treatment. These results suggest that the local and transient expression of E-cadherin in embryonic brain is involved in regional pattern formation in this organ.

Animals

[Acute toxicity study of 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethanesulfonate (FUT-187) in mice, rats and dogs.

Single oral, subcutaneous or intravenous administration to mice and rats and oral administration to dogs were performed to investigate the acute toxicity of FUT-187. 1) LD50 values in mice were 4,395 mg/kg for males and 3,626 mg/kg for females orally, 6,284 mg/kg for males and 5,492 mg/kg for females subcutaneously, and 39.4 mg/kg for males and 41.4 mg/kg for females intravenously. In rats, these values were 4,653 mg/kg for males and 3,761 mg/kg for females orally, 6,799 mg/kg for males and 3,343 mg/kg for the females subcutaneously and 21.8 mg/kg for males and 15.8 mg/kg for females intravenously. 2) Death occurred 2 hours after administration in a male dog of the 3,000 mg/kg group just after convulsion and nasal discharge were observed. 3) General symptoms in mice and rats included a creeping gait, convulsion, singultus, cyanosis, decreased locomotor activity, piloerection and salivation which were commonly observed by all routes. All dogs showed vomiting and decreased locomotor activity; the prone or lateral position, crouching, ataxic gait and salivation were also observed in many cases. 4) On autopsy, changes attributable to local irritation by FUT-187 were seen in all species except mice and rats dosed intravenously. For the gastro intestinal-tract (GIT), inflammation of the stomach, adhesions between the stomach and the liver and sclerosis, petechiae or ulcer were observed in mice and rats dosed orally. In the subcutaneous route, retention of the test compound and necrosis at the injection site were observed. Reddening and loss of mucosal smoothness were observed in the GIT of a dog which died; desquamation, congestion, hemorrhage and retention of tested compound in the digestive mucosa were observed on histopathology.

Administration, Oral

[Reproductive and developmental toxicity studies of FUT-187. (I)--Fertility study in rats with oral administration of FUT-187].

FUT-187 was given orally at 20, 120 and 720 mg/kg during the pre-pairing period (63 days prior to pairing in males and 14 days prior to pairing in females) and the pairing period to male and female rats and in the early stage of pregnancy (days 0 through 7 of gestation) to female rats, and the effects of the test compound on male and female reproductive performance and fetal development were evaluated. One male of the 720 mg/kg group died due to treatment. Temporary salivation was observed in males and females in the 20 mg/kg or more groups. In males, increases in the weight of the pancreas in the 120 mg/kg or more groups and the adrenals in the 720 mg/kg group, a depression of body weight gain and decreases in food intake and weight of the carcass in the 720 mg/kg group were statistically significant in comparison with controls. In females, an increase in the weight of the pancreas in the 120 mg/kg or more groups, a slight depression of body weight gain during the early stage of pregnancy and a decrease in the food intake, and a decrease in the weight of the carcass in the 720 mg/kg group were statistically significant in comparison with controls. No dose-related changes were found in the estrus, copulation, insemination and fertility indices. In fetuses, decreased numbers of corpora lutea, implantation and live fetuses were observed in the 720 mg/kg group. There were no treatment-related abnormalities in fetal mortality, sex ratio, weights of fetuses and placenta, and external and visceral examinations. Based on these results, it is concluded that the no-effect-dose levels of FUT-187 are less than 20 mg/kg for the parents, 720 mg/kg for reproductive performance and 120 mg/kg for fetal development.

Administration, Oral

[Reproductive and developmental toxicity study of 6-amidino-2-naphthyl 4(-)[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethanesulfonate (FUT-187). (II)--Oral administration to rats during the period of fetal organogenesis (prenatal examination)

6-Amidino-2-naphthyl 4(-)[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethanesulfonate (FUT-187) was given orally to pregnant Crj : CD (Sprague-Dawley) rats from days 7 through 17 of gestation at dose levels of 50, 200 and 800 mg/kg/day. In the 800 mg/kg/day group, salivation just after dosing, suppression in body weight gain and decreased food consumption were observed. No external, visceral and skeletal anomalies attributable to FUT-187 were observed in fetuses. From the present result, it is considered that the no-effect dose level of FUT-187 for dams and fetuses are 200 mg/kg/day and 800 mg/kg/day respectively.

Administration, Oral

[Reproductive and developmental toxicity studies of FUT-187. (III)--Postnatal study in rat F1 offspring from dams treated orally with FUT-187 during the period of fetal organogenesis].

A postnatal study of F1 offspring exposed to FUT-187 during fetal organogenesis was carried out using Crj : CD rat. FUT-187 was dosed by gavage at 0, 50, 200 and 800 mg/kg/day from day 7 to 17 of gestation. All pregnant rats were allowed to deliver newborns, and F1 offspring were examined for development indices and reproduction and learning ability. Effects at 800 mg/kg included temporary salivation, body weight depression and decreased food intake. There were no adverse effects on delivery and lactation and no significant changes on neonatal development, growth, reproduction and learning ability in the F1 offspring. These results indicate that the no effect dose level of FUT-187 is 200 mg/kg/day in dams, and 800 mg/kg/day in offspring.

Abnormalities, Drug-Induced

[Reproductive and developmental toxicity studies of 6-amidino-2-naphthyl 4(-)[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethanesulfonate (FUT-187). (IV)--Oral administration to New Zealand white rabbits during the period of fetal organogenesis.

Oral administration of 6-amidino-2-naphthyl 4(-)[(4,5-dihydro-1H-imidazol-2-yl)amino] benzoate dimethanesulfonate (FUT-187) at doses of 10, 30 and 100 mg/kg was given to New Zealand White rabbits on days 6 to 18 of gestation. The following results were obtained. Decreased food consumption and suppression of body weight gain in dams were observed and these changes contributed to the increase in aborted or prematured births and increased fetal mortality at the 100 mg/kg group. There were changes attributable to FUT-187 on external, skeletal and visceral examinations of fetuses. Based on the above, the no-effect dose level in dams and fetuses in the present study is 30 mg/kg/day.

Administration, Oral

[Reproductive and developmental toxicity studies of FUT-187. (V)--Perinatal and postnatal study in rats with oral administration of FUT-187].

FUT-187 was given orally at 20, 120 and 720 mg/kg to female rats during the perinatal and postnatal periods and the effect on dams and offspring were evaluated. One dam during the terminal period of gestation and 3 dams after delivery in the 720 mg/kg group died due to FUT-187. In dams, an increased pancreas weight in the 20 mg/kg or more groups, temporary salivation after dosing in the 120 mg/kg or more groups, and a depression of body weight gain and decreased food intake and weight of the carcass in the 720 mg/kg group were statistically significant in comparison with controls. In offspring, postnatal death rate in the 720 mg/kg group tended to increased. Decreased body weight gain and delayed appearance of abdominal hair and descent of testis in the 720 mg/kg group were statistically significant in comparison with controls. There were no treatment-related abnormalities in visceral examination, organ weight, skeletal examination, sensory function, behavioral function, learning ability or reproductive function. Based on these results, it is concluded that the no-effect-dose levels of FUT-187 are less than 20 mg/kg for dams, and 120 mg/kg for reproductive performance of dams and offspring development.

Abnormalities, Drug-Induced

[Antigenicity study of 6-amidino-2-naphthyl 4(-)[(4,5-dihydro-1H-imidazol-2-yl)amino] benzoate dimethanesulfonate (FUT-187) in guinea pigs and mice.

Antigenicity study of 6-amidino-2-naphthyl 4(-)[(4,5-dihydro-1H-imidazol-2-yl)amino] benzoate dimethanesulfonate (FUT-187), a new protease inhibitor, was investigated in guinea pigs and mice and the following results were obtained. 1. In guinea pigs immunized with FUT-187 plus adjuvant by intramuscular/subcutaneous routes, ASA, ACA and PCA reactions challenged intravenously or intradermally were positive. 2. In guinea pigs immunized with FUT-187 plus adjuvant by intramuscular/subcutaneous routes, ASA and PCA reactions challenged orally were negative. 3. In guinea pigs immunized with FUT-187 by the oral route, ASA, ACA and PCA reactions were negative. 4. In guinea pigs immunized with IABA and AN plus adjuvant by intramuscular/subcutaneous routes, ASA and PCA reactions were negative. 5. 48-hr PCA reactions were elicited with sera obtained from BALB/c and C3H/He mice immunized with FUT-187 plus adjuvant by the intraperitoneal route, responses were negative. 6. From the results of hapten inhibition tests using anti-FUT-187 guinea pig serum, it is suggested that the antigenicity of FUT-187 is attributable to the its benzoic acid.

Adjuvants, Immunologic

[A 13-week subacute oral toxicity study of 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethanesulfonate (FUT-187) in dogs.

A subacute oral toxicity study of 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethanesulfonate (FUT-187), a new protease-inhibiting agent, was carried out in beagle dogs of both sexes. FUT-187 was administered to dogs at daily oral doses of 15, 50 and 150 mg/kg. Dogs in 150 mg/kg group were given twice a day in a.m. and p.m.. The results were as follows: 1. Changes of physical sign attributed to FUT-187, consisted of vomiting, diarrhea, salivation, decrease of locomotor activity, sedation and hyperemia of eye mucosa. These changes expect vomiting vanished within about 2 hours after treatment. One male given 150 mg/kg died on day 19 and two females given 150 mg/kg were sacrificed on day 55 and 67 due to deterioration of systemic conditions. 2. Body weight gain was suppressed in males given 150 mg/kg and females given 50 mg/kg or more. 3. In hematological examinations, some changes suggesting anemia or inflammation were observed in a few animals received 50 mg/kg or more 4. In serum biochemical examinations, dogs given 50 mg/kg or more had decrease of albumin, total protein, A/G ratio and total cholesterol, increase of GPT activity. In liver function test, decrease of function was observed in a few animals in 150 mg/kg group. These changes diminished by the end of recovery period. 5. In autopsy findings, ulcer formation and desquamation of mucosa in the digestive tract were observed in dead or sacrificed animals and survived animals given more than 50 mg/kg. In sacrificed animals, liver was yellow in color and intussusception was seen. 6. Plasma levels of intact FUT-187 and metabolites on the day 37 or 83 were higher than that on the first day of administration. 7. In histopathological examinations, ulcer formation, desquamation, degeneration and/or atrophy of mucosa in the digestive tract were observed in the animals from 50 mg/kg and 150 mg/kg groups. In addition, fatty deposition in hepatocytes was observed in one dead animal and two sacrificed animals.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral

[Flow cytometric techniques for measurement of proliferating cell nuclear antigen (PCNA)].

Flow cytometric techniques have been developed for measurement of proliferating cell nuclear antigen (PCNA), which allows studies on the proliferative capacity of cells and tissues. PCNA-DNA dual staining procedures, for both fixed and unfixed cells, and analytical method by FCM are presented. We recommend performing either the fixed or unfixed method. Our studies using the MCF7 human breast adenocarcinoma cell line and the A549 human lung squamous cell carcinoma cell line, in the exponential growth phase, revealed that both ethanol and acetone were satisfactory fixatives, in contrast to methanol and paraformaldehyde, and PI with a concentration of 25 micrograms/ml was most suitable compared with 50 and 100 micrograms/ml.

Adenocarcinoma