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Biomedical subjects

S Yoshida

Publications and source records attributed to S Yoshida.

At least 721 records · Page 40Linked to original sources
PubMed1997

Crystallization and preliminary X-ray analysis of neuropsin, a serine protease expressed in the limbic system of mouse brain.

Neuropsin (M(r) 25032) is a serine protease expressed in the limbic system of mouse brain. It has been implicated in various neurological processes including formation of memory and may be important as a drug target in the treatment of epilepsy. The recombinant protein was produced using a baculovirus expression system and was purified. Two crystal forms were obtained by a hanging-drop vapor-diffusion method with polyethylene glycol. Preliminary X-ray crystallographic analysis revealed that crystal form I belongs to triclinic space group P1 with unit cell dimensions a = 97.16 A, b = 97.12 A, c = 46.75 A and alpha = 99.17 degrees, beta = 99.77 degrees, gamma = 117.35 degrees. Self-rotation function analysis of these data of form I indicates the position of a noncrystallographic threefold axis. There are six molecules in the crystallographic asymmetric unit. Crystal form II also belongs to triclinic space group P1 but has unit cell dimensions of a = 38.40 A, b = 55.16 A, c = 65.37 A and alpha = 95.38 degrees, beta = 89.98 degrees, gamma = 110.46 degrees with two molecules in the crystallographic asymmetric unit. Form II has a noncrystallographic twofold axis. Intensity data to 3.1 A resolution for form I and to 2.2 A resolution for form II have been collected.

Amino Acid Sequence↗
PubMed1997

Identification of lymphatic vessels by using a monoclonal antibody specific for the human thoracic duct.

Light microscopic identification of lymphatic vessels of the human small intestine was studied immuno-histochemically with a monoclonal antibody specific for human thoracic duct (mAb-D) and rabbit anti-human laminin antibody (anti-L). Two types of vessels were observed with anti-L; one strongly reacted with regularly outlined vessels and the other weakly reacted with irregularly outlined vessels and thin walls. Immunoreactivity to mAb-D was strong in the weakly reacting vessels, and the strongly reacting vessels did not react to mAb-D. Immunoreactivity of lymphatic vessels to anti-L has been reported to be weaker than that of the blood vessels; only irregularly outlined vessels which were weakly immunostained with anti-L reacted to mAb-D and no cross-reaction to mAb-D was observed in the regularly outlined vessels. This indicates that the vessels strongly reacting with anti-L are blood vessels and the vessels immunostained with mAb-D must be lymphatics. The study shows that it is possible to identify lymphatic vessels light microscopically by mAb-D. This method will be useful in studying the fine distribution of lymphatic vessels in normal tissue and also in pathological tissue such as metastasis of malignant tumors.

Aged↗
PubMed1997

Stimulatory effect of reconstituted basement membrane components (matrigel) on the colony formation of a panel of human lung cancer cell lines in soft agar.

Lung cancers have been distinguished into small-cell lung cancer (SCLC) and non-small cell-lung cancer (NSCLC) types on the basis of their clinical behaviors and their responses to treatment. Moreover, growth of most SCLC cell lines in liquid culture medium is nonadherent, while that of most NSCLC cell lines is adherent. In this study, we examined the effect of matrigel (reconstituted basement membrane components), which is known to have growth-stimulatory activity on various human tumor cell lines in immunodeficient mice, on soft-agar colony formation of a panel of SCLC and NSCLC cell lines to clarify its mechanism of growth stimulation of cancer cells. Matrigel enhanced colony formation of all 9 NSCLC cell lines and 4 of 9 SCLC cell lines. There was a statistically significant difference (P < 0.01) between colony formations with and without matrigel of NSCLC cell lines, but not for SCLC cell lines. In liquid culture medium, all 9 NSCLC lines and 3 of 9 SCLC lines adhered to plastic dishes, whereas the other SCLC lines did not. Matrigel enhanced colony formation of all 3 adherent-type SCLC lines and 1 of 6 nonadherent-type NSCLC lines. Matrigel enhanced colony formation of both of 2 adherent-type non-lung cancer cell lines and 1 of 2 nonadherent-type leukemia cell lines. Neither transforming growth factor beta, collagen type IV, fibronectin, nor laminin, which are components of matrigel, enhanced colony formation of an NSCLC cell line in soft agar. The increase in the colony number of the NSCLC cell line by matrigel was abrogated by the protein kinase inhibitors staurosporine and UCN-01.

Adult↗
PubMed1997

Expression of transforming growth factor alpha (TGF-alpha) gene in mouse embryonic development.

PURPOSE: The expression of genes for TGF-alpha, epidermal growth factor (EGF), and the EGF receptor (EGFR) in mouse blastocysts was evaluated by the reverse transcription-polymerase chain reaction (RT-PCR). We evaluated the effects of TGF-alpha and EGF on the development of mouse embryo prior to implantation. RESULTS: The results revealed the presence of transcripts of TGF-alpha and EGFR. However, EGF mRNA was not observed in repeated experiments. None of these growth factors influenced the rate of development from the two-cell stage to the blastocyst stage when added to the culture medium. These effects were further examined on measuring the incorporation of tritiated thymidine and leucine, providing indices of the synthesis of DNA and protein, respectively. A concentration of only 0.1 ng/ml of TGF-alpha, which shares a cell surface receptor with EGF, stimulated the synthesis of both DNA and protein. EGF at a concentration of 10 ng/ml stimulated the synthesis of DNA and protein by blastocysts. To explore autocrine effects of TGF-alpha on the rate of blastocoel expansion, TGF-alpha antisense oligodeoxynucleotides was used to reduce expression of the TGF-alpha gene. TGF-alpha at a concentration of 0.1 ng/ml stimulates the rate of blastocoel expansion in early cavitating mouse blastocysts. In contrast, TGF-alpha antisense oligonucleotides significantly reduced the rate of expansion. CONCLUSIONS: Our present observations suggest that TGF-alpha/EGF and the EGFR may be involved in regulating embryonic development. In particular, TGF-alpha may serve as an autocrine factor in the regulation of embryonic development.

Animals↗
PubMed1997

Subcellular distribution of thallium: morphological and quantitative study in rat myocardium.

UNLABELLED: The purpose of this study is to determine the subcellular distribution of thallium (SDTl) by electron microscopy and a newly designed fixation method that makes insoluble grains of Tl visible. METHODS: To obtain the high dose necessary for electron microscopic visualization, we employed TlCl instead of 201TlCl. EM was performed in fixed rat myocardium resected at 20 min (early phase) and 3 hr (delay phase) after intravenous injection of TlCl. To fix Tl in the cell, we used orthovanadate in our fixative. Atomic absorption spectroscopy (AAS) of Tl and quantification of subcellular distribution of 201Tl (SD201Tl) were studied to prove the propriety of our fixation. RESULTS: AAS detected Tl in the Tl-loaded specimen but not in the control, indicating that Tl was the origin of the grains observed in the former. In the early phase, numerous grains were observed in mitochondria, sarcoplasmic reticulum (SR), myofibrils, and nuclei, but no such grains were visible in controls. In the delay phase, grains were retained in mitochondria, SR and nuclei, but not in myofibrils. Electron microscopic SDTl(%) correlated with SD201Tl(%) calculated from isolated fractions. CONCLUSION: In both the early and delay phases, mitochondria are the major site of Tl and 201Tl uptake.

Animals↗
PubMed1997

Developmental expression of a novel Kexin family protease, PACE4E, in the rat olfactory system.

PACE4 is a mammalian Kexin family protease that is involved in the maturation of precursor proteins. Four PACE4 isoforms have been identified. We identified a novel PACE4 isoform, PACE4E, from a human cerebellum cDNA library, which possesses a hydrophobic cluster in its C-terminus participating in membrane association. The size of PACE4E mRNA from adult rat brain was estimated by Northern blotting to be 4.4 kb. In situ hybridization histochemistry revealed that the highest level of PACE4E mRNA was expressed in the mitral cells of the adult rat olfactory bulb (OB). The OB is a unique sensory organ in that it has a lifelong regenerating capacity and it affects brain development. We further analyzed the expression of PACE4E mRNA in the developing olfactory system. On day 13.5 of gestation, PACE4E mRNA was expressed at high levels in the neuroepithelium of the forebrain vesicle (FV), olfactory epithelium, and cells in the fiber bundles projecting to the FV. As development proceeded, PACE4E mRNA was expressed in developing mitral cells but decreased in the olfactory epithelium. In the newborn, its expression was confined to the mitral cells in both the main and accessory OB and in some periglomerular cells, as shown in adult rats. The spatio-temporal expression of PACE4E suggests that it plays a role in the establishment and maintenance of the olfactory receptor system.

Animals↗
PubMed1997

A missense mutation in the SOD1 gene in patients with amyotrophic lateral sclerosis from the Kii Peninsula and its vicinity, Japan.

Unusually high incidences of amyotrophic lateral sclerosis (ALS) have been observed in the natives of the Kii Peninsula of Japan as well as the indigenous Chamorro people of Guam. Given the relatively high incidence of familial onset of the disease in the Kii Peninsula, we performed mutational analyses of the SOD1 gene of 23 patients (three familial cases and 20 sporadic cases) with ALS from the Kii Peninsula and its vicinity. In two of the 23 patients, we identified the same missense mutation (substitution of Thr for Ile 113) in exon 4 as a heterozygous state. The Ile 113Thr mutation in the SOD1 gene has been identified in some familial as well as sporadic cases with ALS, as a mutation with a low penetrance. This mutation has been reported to be associated with the formation of neurofibrillary tangles in an English family, which is a characteristic feature of ALS in the Kii Peninsula. These results suggest that the Ile113Thr mutation is a characteristic and relatively prevalent mutation in this area.

Adult↗
PubMed1997

Increased interleukin-6 levels in peritoneal fluid of infertile patients with active endometriosis.

OBJECTIVE: Our purpose was to investigate the relationship between the levels of interleukin-6, interleukin-6 soluble receptor, and tumor necrosis factor-alpha in peritoneal fluid and the size and number of active red endometriotic lesions. STUDY DESIGN: In a university hospital 39 women of reproductive age underwent either laparoscopy for infertility workup or laparoscopic surgery for ovarian chocolate cysts. Peritoneal fluid was collected by laparoscopy. Active lesions, such as red flamelike lesions, glandlike lesions, and red vesicles, were scored according to the revised American Fertility Society classification system according to the size and number of active lesions. Peritoneal fluid levels of interleukin-6, interleukin-6 soluble receptor, and tumor necrosis factor-alpha levels were determined by enzyme-linked immunosorbent assays. The relationship between peritoneal fluid concentrations of interleukin-6 and tumor necrosis factor-alpha and the score of active endometriosis was investigated. RESULTS: Peritoneal fluid levels of interleukin-6 and tumor necrosis factor-alpha were significantly higher in patients with endometriosis compared with patients without endometriosis. The concentrations in patients with active endometriosis increased as the size and the number of active lesions increased. Cyclic variations in interleukin-6 concentrations were seen in peritoneal fluid from patients with endometriosis; the concentrations in the secretary phase were significantly higher than those in the proliferative phase. CONCLUSIONS: Increased peritoneal fluid levels of interleukin-6 in patients with active red endometriosis may relate to endometriosis-associated infertility and to the pathogenesis of endometriosis.

Adult↗
PubMed1997

Cultured retinal pericytes stimulate in vitro angiogenesis of endothelial cells through secretion of a fibroblast growth factor-like molecule.

Interaction between cultured endothelial cells (EC) and pericytes (PC) was studied in vitro to clarify the mechanism of diabetic proliferative retinopathy. Conditioned medium (CM) from retinal PC strongly increased the proliferation and moderately stimulated migration of retinal EC. Moreover, CM from PC caused stimulation of angiogenesis of retinal EC and umbilical cord vein EC in vitro at the same extent as basic fibroblast growth factor (bFGF). PC also stimulated angiogenesis by EC in mixed cultures. The angiogenic, proliferative and migration activities in CM from PC were inhibited by an antibody to bFGF. These data suggest that PC play an important role in angiogenesis through secretion of an FGF-like molecule.

Animals↗
PubMed1997

Early morphologic changes of atherosclerosis induced by ventromedial hypothalamic lesion in the spontaneously diabetic Goto-Kakizaki rat.

It is generally thought that typical atherosclerotic lesions do not develop in the rodent. The Goto-Kakizaki (GK) rat is a nonobese strain in which a spontaneous type of non-insulin-dependent diabetes mellitus develops without apparent macroangiopathy. In our previous study, making ventromedial hypothalamic (VMH) lesions in GK rats induced hyperphagia and a further deterioration in glucose metabolism. In the current study, male GK rats in which VMH lesions were made were examined for vascular changes, with special reference to atherosclerotic lesions. Marked hyperglycemia in GK rats with VMH lesions (hereafter referred to as VMH lesion rats) was revealed over an observation period (plasma glucose levels 16 weeks after the operation: VMH lesion GK rats, 19.3 +/- 2.0 mmol/L, vs sham-operated GK rats, 10.1 +/- 1.3 mmol/L; p < 0.0001). Light microscopic observation of the descending aorta in VMH lesion GK rats 16 weeks after the surgery revealed that the intimal thickening and the number of infiltrating cells into the intima were significantly increased as compared with sham-operated GK rats (17531 +/- 3747 microm2 vs 3072 +/- 1192 microm2, p < 0.0001; 15.6 +/- 3.1 per one transverse section vs 6.8 +/- 2.5 per one transverse section, p < 0.0005). Electron microscopic observations demonstrated an increased number of microvilli and lysosomes in endothelial cells, infiltration of macrophages and lymphocytes into the intima, and migration of medial smooth muscle cells into the intima that are considered to be early events in atherosclerosis. These morphologic changes could be induced by a deterioration in glucose metabolism. This rat may thus be useful for studying the process of the initiation of atherosclerosis in diabetes mellitus.

Animals↗
PubMed1997

Effects of X-irradiation on the calcium channel of the mouse oocyte.

Effects of a single whole-body X-irradiation (0.2-100 Gy) were studied on Ca2+ channels in mature mouse oocytes using the two-electrode voltage-clamp method. No significant changes were observed in the electrophysiological properties of oocytes when the dose of X-rays was smaller than 10 Gy. However, the following changes, dependent on the dose of X-rays and on the time after irradiation, were observed with higher doses. 1) The resting potential and the input resistance of the oocyte were slightly reduced. 2) Inward Ca2+ current was reduced in amplitude but the shape of the I-V (current-to-voltage) relations were preserved. 3) Both the activation and the inactivation processes of the Ca2+ current became slower. These changes in the kinetics of the Ca2+ channel were observed even when no appreciable change was detected in the amplitude of the Ca2+ current. 4) The steady-state inactivation curve of the Ca2+ current was shifted in a depolarizing direction and the slope of the curve became steeper. These data indicate that high doses of X-rays can affect Ca2+ channels in mouse oocytes and that the kinetics of the Ca2+ channel are more susceptible to irradiation than the amplitude of the Ca2+ current.

Animals↗
PubMed1997

Glutamine and arginine metabolism in tumor-bearing rats receiving total parenteral nutrition.

Arginine supplementation increases glutamine levels in muscle and plasma. Since glutamine production is increased in catabolic states, these observations prompted us to investigate whether the flux of arginine to glutamine was increased in tumor-bearing (TB) rats, and we measured the synthesis rate of glutamine from arginine in control versus TB rats receiving standard total parenteral nutrition (TPN) solution. Male Donryu rats (N = 36; body weight, 200 to 225 g) were divided into two groups, control and TB rats. Yoshida sarcoma cells (1 x 10(6)) were inoculated into the back of the rats (n = 18) subcutaneously on day 0. The rats were given free access to water and rat chow. On day 5, all animals, including non-TB rats (n = 18), were catheterized at the jugular vein and TPN was begun. On day 10, TPN solution containing either U-14C-glutamine (2.0 microCi/h) or U-14C-arginine (2.0 microCi/h) was infused as a 6-hour constant infusion. At the end of the isotope infusion, plasma was collected to determine the glutamine production rate in rats receiving U-14C-glutamine, and the ratio of specific activity of glutamine to specific activity of arginine was measured in rats receiving U-14C-arginine. Only 2 g tumor caused a decrease in glutamine levels and an increase in glutamine and arginine production. The low flux rate of arginine to glutamine was observed in control rats (Arg to Gln, 41.0 +/- 11.9 mumol/kg/h). On the other hand, TB caused a significant increase in Arg to Gln compared with the control (213.3 +/- 66.1 mumol/kg/h, P < .01 v control). An increase in the flux rate of Arg to Gln was associated with an enhancement in the ratio of specific activity of ornithine to specific activity of arginine in TB rats (control 51.5% +/- 10.9% v 77.4% +/- 8.9%, P < .05). We conclude that (1) glutamine and arginine metabolism is altered with very small tumors, (2) although the flux of Arg to Gln was increased in TB and rats, the small increase in Arg to Gln cannot explain the observed large increase in Gln production.

Animals↗
PubMed1997

Ultrasound biomicroscopic view of detachment of the ciliary epithelium in retinal detachment with atopic dermatitis.

PURPOSE: The authors evaluated the effectiveness of ultrasound biomicroscopy to determine the condition of the ciliary body during perioperative examinations of patients with atopic dermatitis and retinal detachment. METHODS: The authors compared two groups of patients with atopic dermatitis and retinal detachment. Parameters included patient age, gender, eye, cataract, type and location of breaks, macular involvement, detachment of the ciliary epithelium, and preoperative and postoperative best-corrected visual acuities. Group 1 included six patients (nine eyes) who were examined before surgery and after surgery using ultrasound biomicroscopy, with which the authors also measured the maximum height of the detachment of the ciliary epithelium. Group 2 included 10 patients (13 eyes) who did not undergo ultrasound biomicroscopy. RESULTS: In group 1, ultrasound biomicroscopy showed ciliary epithelium detachment in all eyes before surgery and in eight of nine eyes after successful retinal reattachment. The height of the ciliary detachment, however, decreased dramatically after surgery. Although almost all the parameters between groups 1 and 2 were similar, the authors observed a significant difference in the incidence of preoperative diagnosis of ciliary detachment (P = 0.023). CONCLUSION: Ultrasound biomicroscopy is beneficial in detecting detachment of the ciliary epithelium. The residual shallow detachment that remains after successful surgery suggests the fragility of the ciliary body.

Adolescent↗
PubMed1997

Effects of lidocaine on salicylate-induced discharge of neurons in the inferior colliculus of the guinea pig.

Using the extracellular recording method, the effects of lidocaine (a local anesthetic known to relieve tinnitus) on discharge of inferior colliculus (IC) neurons of the guinea pig were studied before and after salicylate (200 mg/kg) administration. The salicylate-induced discharge was inhibited by intravenous injection of lidocaine at a concentration (1 mg/kg) clinically used for treating tinnitus. IC neurons could be classified into two groups according to the difference in sensitivity to lidocaine: (1) weakly-sensitive neurons and (2) highly-sensitive neurons. In weakly-sensitive neurons, the duration of the lidocaine effect lasted for less than 5 min, and the inhibitory action on the discharge of neurons was greater when the latency to sound stimulus became longer. In highly-sensitive neurons, on the other hand, the activity of neurons was almost completely inhibited for longer than 30 min, irrespective of the latency to sound stimulus. The clinical relevance of these types of neurons is discussed.

Action Potentials↗
PubMed1997

Characteristics of long-term psychiatric patients hospitalized in Tokyo, Japan.

This study examined the records of all psychiatric patients hospitalized over 1 year who were committed as a result of a penal code violation at a public sector hospital located in Tokyo, Japan. The 30 patients were all men, Japanese, and primarily unmarried. Affective and organic disorders were totally absent. None of the new antipsychotic medications were used. There was no relationship between nursing diagnosis and Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) diagnosis. The demands for health care reform are beginning in Japan. Managing the integration of the long-term psychiatric patient into the community is one of the main challenges identified in this study.

Adult↗
PubMed1997

Effects of haloperidol and cocaine pretreatments on brain distribution and kinetics of [11C]methamphetamine in methamphetamine sensitized dog: application of PET to drug pharmacokinetic study.

Repeated administration of methamphetamine (MAP) causes behavioral sensitization in animals. We previously reported that the maximum accumulation level of [11C]MAP in the MAP-sensitized dog brain was 1.4 times higher than that in the control. In behavioral studies, haloperidol (a dopamine D2 receptor antagonist) prevents MAP-induced behavioral sensitization, and cocaine (a dopamine reuptake blocker) has the cross-behavioral sensitization with MAP. In the present study, to elucidate the relation between the MAP-induced behavioral sensitization and the pharmacokinetics of MAP, we investigated the effects of haloperidol and cocaine pretreatments on brain regional distribution and kinetics of [11C]MAP using positron emission tomography (PET). A significant increase of [11C]MAP uptake into the sensitized dog brain was prevented by haloperidol and cocaine pretreatments. These pharmacokinetic changes were not due to the changes in the rate of MAP metabolism. These results suggest haloperidol and cocaine can change the cerebral pharmacokinetic profile of MAP in the behavioral-sensitized dog. The variations of MAP-accumulation may affect the development or expression of MAP-induced behavioral sensitization.

Animals↗
PubMed1997

Donor-specific cytotoxic lymphocyte activity from bronchoalveolar lavage during acute canine lung allograft rejection.

OBJECTIVE: We investigated the relationship between acute lung rejection and donor-specific cytotoxic activity (DSCA) in recipient's lymphocytes obtained from bronchoalveolar lavage (BAL). METHODS: A total of 26 mongrel dogs underwent left lung allotransplantation. Dogs received either no immunosuppressive treatment (group I), cyclosporine (group II), or cyclosporine and methylprednisolone for evidence of acute rejection (group III). DSCA was measured by a 51Cr release assay, using lymphocytes from BAL samples as effector cells and 51Cr-labeled donor skin fibroblasts as target cells. The pathologic findings of the transplanted lungs were classified according to the working formulation for classification and grading of pulmonary rejection. In addition, the degree of cellular infiltration in the perivascular, peribronchial, interstitial, and intraalveolar areas was determined based on an infiltration score. RESULTS: DSCA in BAL samples was elevated during mild, moderate and severe acute rejection. The accuracy of the diagnosis of mild or moderate rejection was 92.3% at effector:target (E:T) ratios of 100:1 and 50:1. The DSCA in the BAL fluid and the total infiltration score were correlated closely with correlation coefficients of 0.859 and 0.828 at E:T ratios of 100:1 in group I and group II dogs, respectively. Lung aeration improved and DSCA decreased with methylprednisolone therapy in three of four dogs with grade 2 rejection. CONCLUSION: There is a direct relationship between the DSCA in BAL fluid and the degree of tissue damage caused by acute rejection. The DSCA can be detected by a 51Cr release assay which may hold promise for future clinical applications.

Animals↗