Biomedical subjects

K Goto

Publications and source records attributed to K Goto.

At least 361 records · Page 20Linked to original sources

PubMed1996

The prevalence of Toxoplasma antibody in patients with various ocular diseases in central Japan.

BACKGROUND: Ocular toxoplasmosis has been considered to be a largely asymptomatic infection because of the high seroprevalence of Toxoplasma antibodies and the low rate of clinical diagnosis. On the other hand, Toxoplasma infection has been reported to be associated with the other ocular disease. To investigate the association of Toxoplasma infection with the development of various ocular diseases, we studied Toxoplasma seroprevalence in patients with various ocular diseases. METHODS: We investigated Toxoplasma seroprevalence in 982 patients with various ocular diseases in central Japan. Then we compared the seroprevalence of anti-Toxoplasma antibodies. RESULTS: Of 982 patients with various ocular diseases, 122 (12.4%) had serological evidence of previous exposure to Toxoplasma gondii. There were no statistically significant differences among the patients with various ocular diseases. However, the seroprevalence in patients aged 40 to 99 years with macular degenerative lesions was significantly higher than that in patients without these lesions (P < 0.05, Yates' correction). CONCLUSION: This result suggests that Toxoplasma infection could play some role in the development of a type of macular degenerative lesion.

Adolescent↗

PubMed1996

Inferior vena caval thrombus associated with double neoplasms of the retroperitoneum and kidney: report of a case.

We report herein the case of a patient we recently encountered who was found to have a giant retroperitoneal tumor coincident with tumor thrombus in the inferior vena cava (IVC). On the assumption that the origin was retroperitoneal, the two lesions were resected using an intracaval filter. However, histopathological examination of the specimens revealed neurilemoma for the retroperitoneal tumor and adenocarcinoma for the tumor thrombus. A right renal tumor was subsequently detected, which led to right nephrectomy being performed en bloc with part of the IVC using a venoarterial bypass. Microscopy revealed carcinoma of the Bellini duct, or collecting duct, which is an extremely rare tumor. Retrospectively, a lesion with soft tissue density was noted in the renal vein. Surgical management focused on the prevention of pulmonary embolism. We describe this case because of its extreme rarity and its significance from the viewpoint of diagnosis and therapeutic strategies.

Aged↗

PubMed1996

The neural origin generating early cortical components of SEP: topographical analysis using temporal-second-order-differentiation of cortical SEPs.

In order to identify dipole generators of the N20/P20 and P25, we employed second-order-differentiation in the temporal dimension (temporal-second-order-differentiation; TSOD) with delta t = 2 msec. The rate of variation in the voltage of cortical SEPs calculated by TSOD identified responses of each dipole, reflecting the density of neuronal firing. On topographic analysis, the distributions of N20/P20 and P25 conformed to the shape of gyrus better in the TSOD maps than in the isovoltage maps. The TSOD maps indicated that N20 and P25 were post-central components and that P20 was a pre-central one. Therefore, we concluded that the two dipoles generating N20/P20 and P25 were located in the posterior wall of the central sulcus (area 3b) and the crown (areas 1 and 2) of the post-central gyrus, respectively.

Brain Mapping↗

PubMed1996

Histochemical detection of apoptosis in Parkinson's disease.

Apoptosis may be an important mechanism of cell death in some experimental disease models as well as in human neurodegenerative disorders. We report evidence to indicate apoptosis in the substantia nigra of Parkinson's disease patients. We studied the midbrains of 7 patients with late onset PD, 4 patients with young onset PD and 6 control subjects using the nick-end labeling method. Intense nuclear staining indicating apoptotic process was observed in 8 out of 11 parkinsonian patients studied. Apoptosis may be a contributor to the nigral neuronal death in Parkinson's disease (PD).

Age of Onset↗

PubMed1996

Plasma endothelin-1 level in athletes after exercise in a hot environment: exercise-induced dehydration contributes to increases in plasma endothelin-1.

We investigated whether dehydration due to exercise contributes to the increase in plasma endothelin-1 (ET-1) concentration. We measured the plasma concentration of ET-1 before and after exercise in a hot environment (about 30 degrees C). Five male intercollegiate Kendo (Japanese fencing) players entered the present study. Each athlete participated in 15 min of Kendo fighting, followed by 5 min of rest and another 15 min of Kendo fighting (i.e., total exercise 30 min), with or without oral intake of 700 ml of water. Body weight and left atrial diameter, a parameter that reflects changes in circulating plasma volume, were significantly decreased after exercise under both conditions. However, the decreases in both values were significantly greater after exercise without water intake than after exercise with water intake, indicating that dehydration and decreased circulating plasma volume were more marked after exercise without water intake. The extent of the increase in plasma ET-1 concentration appeared to be closely related to the extent of exercise-induced dehydration; the greater the dehydration, the greater the increase in plasma ET-1 concentration. These findings suggest that exercise-induced dehydration may contribute to increases in plasma ET-1 concentrations.

Adult↗

PubMed1996

Oxytocin is hydrolyzed by an enzyme in human placenta that is identical to the oxytocinase of pregnancy serum.

The hydrolysis of oxytocin (OT) by human placental subcellular fractions and pregnant sera was studied in the presence of bestatin, a potent inhibitor of aminopeptidases, and the antibody against pregnant serum oxyotocinase (P-LAP)(EC 3.4 11.3) by measuring liberated amino acids by high performance liquid chromatography (HPLC). Our immunotitration study and the effect of bastatin on the oxytocin-degrading protease showed that the initiating and responsible protease in oxyotocin degradation in human placenta and pregnant serum is P-LAP.

Amino Acid Sequence↗

PubMed1996

Calcitonin gene-related peptide (CGRP) induces more potent vasorelaxation in the resistance portion than in the conduit portion of mesenteric arteries in humans.

Although physiological processes related to vascular function differ greatly between resistance arteries and conduit arteries, it is not known whether the effects of calcitonin gene-related peptide (CGRP), a vasodilator neuropeptide, on these arteries differ in humans. In the present study, the conduit portion and the resistance portion of isolated human mesenteric arteries were suspended in a Krebs-Ringer solution. CGRP produced vasorelaxations in both portions. The EC50 values were very low both in the resistance portion (2.4 x 10(-9) M, n = 7) and in the conduit portion (2.2 x 10(-9) M, n = 7). The maximum response to CGRP in the resistance portion was significantly greater than that in the conduit portion (94.6 +/- 4.0% vs. 64.1 +/- 2.6% relaxation of methoxamine-induced precontraction, both n = 7, p < 0.01). These data suggest that CGRP is one of the most potent endogenous vasodilators in both the resistance portion and the conduit portion of the human mesenteric arteries, and that CGRP induces more potent vasorelaxation in the resistance portion than in the conduit portion of these arteries.

Adult↗

PubMed1996

Scavenging effects of tea catechins and their derivatives on 1,1-diphenyl-2-picrylhydrazyl radical.

The scavenging effects of tea catechins and their epimerized, acylated, and glucostylated derivatives on 1,1-diphenyl-2-picrythydrazyl (DPPH) radical were evaluated by electron spin resonance spectrometry. Tea catechins and their epimers were shown to have 50% radical scavenging ability in the concentration range of 1 to 3 microM. No significant differences were observed between the scavenging activities of tea catechins and their epimers, and, hence, the scavenging effects of catechins are not dependent on their sterical structure. The relationship between scavenging ability and the structure of tea catechins was also examined with acylated and glucosylated catechin derivatives. It is suggested that the galloyl moiety attached to flavan-3-ol at 3 position has a strong scavenging ability on the DPPH radical as well as the ortho-trihydroxyl group in the B ring, which elevates the radical scavenging efficiency above that of the ortho-dihydroxyl group; as has been recognized in other flavonoids such as flavones. The results obtained from the reactivity of tea catechins with the DPPH radical at different pHs suggest not only that the ortho-trihydroxyl group and the galloyl moiety contribute to maintaining the DPPH radical scavenging ability more effectively in a wide range of conditions from acidic to alkaline, but also that the radical scavenging efficiency of the ortho-dihydroxyls in the B ring is limited in neutral to alkaline regions. The difference between the scavenging abilities of the trihydroxyls (probably in the galloyl moiety) and the dihydroxyls can be explained in terms of redox potentials. It is concluded that the ortho-trihydroxyl group in the B ring and the galloyl moiety at 3 position of flavan-3-ol skeleton are the most important structural features for displaying an excellent scavenging ability on the DPPH radical.

Bepridil↗

PubMed1996

Heterogeneity of diacylglycerol kinase in terms of molecular structure, biochemical characteristics and gene expression localization in the brain.

Three different cDNA clones for diacylglycerol (DG) kinase were isolated from a rat brain cDNA library and designated DGK-I, DGK-II and DGK-III. These three encode distinct polypeptides with 58% identity to each other and contain EF-hand motifs, cysteine-rich zinc finger-like sequences and putative ATP-binding sites. A high kinase activity is shown in COS cells transfected with either one of the three cDNAs without substrate specificity among DG species, and the kinase activity is Ca-dependent. The activity for DGK-I is recovered dominantly in the soluble fraction of the cell, that for DGK-II in the particulate fraction; and that for DGK-III equally in both of the fractions. The difference in their expression localization is most noticeable: DGK-I is expressed in oligodendrocytes of the brain as well as T-lymphocytes in the thymus and spleen; DGK-II is expressed in neurons of the caudate-putamen, accumbens nucleus and olfactory tubercle; and DGK-III in the cerebellar Purkinje cells and granule cells. The functional significance of the discovery of three DG kinase isozymes is briefly discussed.

Animals↗

PubMed1996

Decreased very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acid expression in placentas from preeclamptic pregnancies.

OBJECTIVE: Our purpose was to investigate the levels of very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acid expression in placentas obtained from normal pregnant women at various gestational stages and from patients with preeclampsia. STUDY DESIGN: The relative level of expression of very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acid in each sample was determined by Northern blot analysis as a ratio of the intensity to that of glyceraldehyde-3-phosphate dehydrogenase messenger ribonucleic acid. RESULTS: The expression of very-low-density lipoprotein receptor messenger ribonucleic acid increased significantly (p < 0.05) from both the first (n = 9) and second (n = 8) trimesters to the third (n = 11) trimester. Similarly, the expression of low-density lipoprotein receptor messenger ribonucleic acid increased significantly (p < 0.05) from the first to the third trimester. The expression of both very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acids in third-trimester placentas from preeclamptic pregnancies (n = 13) was significantly lower than that in normal pregnancies in the third trimester. CONCLUSION: These results demonstrate the expression of very-low-density lipoprotein and low-density lipoprotein receptor messenger ribonucleic acids in the human placenta, both of which increase at late gestational stages, and the decreased expression in cases of preeclampsia. Abnormal fetomaternal lipid metabolism resulting from low expression of these receptors in the placenta may be involved in the pathogenesis of preeclampsia.

Adult↗

PubMed1996

Four-year follow-up study of temporomandibular joint arthroscopic surgery for advanced stage internal derangements.

PURPOSE: This study evaluated the long-term outcome after temporomandibular joint (TMJ) arthroscopic surgery for patients with internal derangement with stage V disease. MATERIALS AND METHODS: Fifteen female patients (24 TMJs) who underwent arthroscopic surgery were evaluated by a questionnaire preoperatively and postoperatively 3 to 5 years later (mean: 4 years, 2 months). The questionnaires consisted of a visual analog scale, pain and jaw dysfunction scores, and self-measured interincisal opening. Clinical examination and conventional radiographic evaluation were done in nine patients (13 joints). Postoperative magnetic resonance imaging was done in two patients (3 joints). RESULTS: All post-treatment scores showed a statistically significant improvement, although joint noise remained in some patients. The radiographic examination revealed mild to moderate degenerative changes, but no abnormal resorption was detected. The surgical success rate was 93.3%. CONCLUSION: Arthroscopic surgery is a useful, minimal invasive, surgical procedure for advanced stage internal derangement of the TMJ.

Adult↗

PubMed1996

Outcome of arthrocentesis for temporomandibular joint with closed lock at 3 years follow-up.

OBJECTIVE: The aim of this study was to evaluate the intermediate term results of arthrocentesis for the management of temporomandibular joint closed lock. STUDY DESIGN: Twenty consecutive patients with closed locking of their temporomandibular joint were treated by arthrocentesis. All patients rated their pain level on a visual analogue scale, and completed pain, jaw dysfunction, and daily activity questionnaires before, 6 months, and 3 years after the procedure. The patients' jaw opening was also scaled. Preoperative and postoperative differences of the data were analyzed statistically. The success rate was also calculated according to our success criteria. RESULTS: The success rate was 70% at 6 months follow-up; it increased to 78.9% over the 3 years of follow-up. All posttreatment scores showed significant improvements in efficacy. CONCLUSION: Arthrocentesis was considered as an effective minimally invasive surgical treatment for temporomandibular joint closed lock based when evaluated 3 years after the procedure.

Adult↗

PubMed1996

Dopamine D2 receptor plays a critical role in cell proliferation and proopiomelanocortin expression in the pituitary.

BACKGROUND: It has been suggested that the dopaminergic system is involved in the inhibitory control of secretion of pituitary hormones and in the regulation of motor function in the striatum. To elucidate the specific role of the dopamine D2 receptor (D2R) in the pituitary and brain, we generated D2R deficient (D2R mutant) mice using the gene targeting method. RESULTS: Electrophysiological studies as well as ligand binding assays show no functional D2R in mutant mice. The D2R mutant mice display a hypoactivity and a slow, creeping movement. The expression of enkephalin mRNA in the striatum is increased in the mutant mice, but not that of dynorphin and substance P. D2R mutant mice have significantly darker coat colour than their wild-type littermates and show an elevation of plasma alpha-melanocyte stimulating hormone (alpha-MSH) levels. We found corresponding hyperplastic changes of intermediate lobe of the pituitary and the increased expression of pro opiomelanocortin (POMC) in the pituitary in D2R mutant mice. CONCLUSIONS: D2R plays a critical role in the inhibitory regulation of endocrine cell proliferation and the transcription of POMC mRNA, and consequently in the regulation of alpha-MSH in plasma. D2R might be involved in the regulation of enkephalin expression in the striatum, and hence might affect the movement and the behaviour.

Animals↗

PubMed1996

Examination of the safety of intracytoplasmic injection procedures by using bovine zygotes.

We have evaluated the safety of intracytoplasmic sperm injection(ICSI) procedures by using bovine zygotes. Bovine zygotes were injected with a small amount (2-3 pl) of either medium alone or medium containing polyvinylpyrrolidone (PVP) (sham-ICSI, without spermatozoon) using the same procedure as ICSI, and the subsequent in-vitro embryonic development and embryo quality (number of cells/blastocyst) were examined. Control zygotes which had not been injected were similarly evaluated after in-vitro development. The sham-ICSI of either medium alone or medium containing PVP into bovine zygotes had no harmful effects on the rate of normal fertilization and on the rate of development to hatched blastocyst stage compared with those of controls (P > 0.05). In addition, no harmful effects were observed in the number of cells per blastocyst (embryo quality). The results suggest, for the first time, that the ICSI procedures currently used for animal and human ICSI are neither detrimental to embryonic development nor detrimental to embryo quality.

Animals↗

PubMed1996

Blastocyst formation following intracytoplasmic injection of in-vitro derived spermatids into bovine oocytes.

Various types of male gametes, such as spermatozoa, spermatids and spermatids obtained after the in-vitro division of secondary spermatocytes, were injected into the in-vitro matured bovine oocytes in order to examine the possibility of utilizing in-vitro derived spermatids for intracytoplasmic injection. There were no significant differences in the development of bovine oocytes injected with various types of male gametes (cleavage rate, 31.0-37.8%; morula rate, 11.1-18.2%; blastocyst rate, 4.4-1.4%). Similarly, 22.0% of sham-injected oocytes (injection of medium plus polyvinylpyrrolidone) cleaved parthenogenetically but none of them developed to morula stage. There were no significant differences in embryo quality (assessed by cell number) of blastocysts obtained by the injections of various types of male gametes (124.0 +/- 9.6-152.5 +/- 15.5). This study demonstrates that various types of spermatogenic cells can be used for intracytoplasmic injection of oocytes to produce viable embryos.

Animals↗

PubMed1996

A case of pregnancy with adult T-cell leukemia.

The incidence of adult T-cell leukemia (ATL) arising in women of childbearing age is documented infrequently. This report is the second in the world's literature of a case of ATL that occurred during pregnancy. A 43-year-old woman developed ATL during pregnancy and died of widespread disease 4 weeks after cesarean delivery.

Adult↗

PubMed1996

Necessity of dual blockade of endothelin ETA and ETB receptor subtypes for antagonism of endothelin-1-induced contraction in human bronchi.

1. Endothelin (ET)-1 has been postulated to be involved in the development of obstructive airway diseases in man. In the present study, we attempted to characterize ET receptor subtypes mediating ET-1-induced contraction in human isolated bronchi. The ET receptor antagonists used in the present study were BQ-123 (ETA receptor-selective), BQ-788 (ETB receptor-selective) and BQ-928 (ETA/ETB dual). Sarafotoxin S6c (S6c) was also used as an ETB receptor-selective agonist. 2. In human bronchi, ET-1 and S6c (10(-12)M to 10(-7) M) produced concentration-dependent contraction with almost equal potency (pD2: 8.88 +/- 0.16 for ET-1 and 9.42 +/- 0.15 for S6c). The contraction induced by S6c was competitively antagonized by BQ-788 alone (1 and 10 microM) with a pKB value of 7.49 +/- 0.21, suggesting that the stimulation of ETB receptors causes a contraction of human bronchi. However, contrary to expectation, the concentration-response curves for ET-1 were not affected by BQ-788. The ET-1- and S6c-induced contractions were not affected by BQ-123 (10 microM). Thus, ET-1-induced contraction of human bronchi is not antagonized by BQ-123 alone or by BQ-788 alone. 3. Combined treatment with 10 microM BQ-123 and 10 microM BQ-788 significantly antagonized the contraction induced by ET-1 with a dose-ratio of 11. BQ-928 also significantly antagonized ET-1-induced contraction with a pKB value of 6.32 +/- 0.24. 4. The specific binding of [125I]-ET-1 to human bronchial membrane preparations was inhibited by BQ-123 (100 pM to 1 microM) by approximately 40%. Combination treatment with BQ-788 (100 pM to 1 microM) completely inhibited the BQ-123-resistant component of [125I]-ET-1 specific binding. 5. In conclusion, the present study demonstrates that BQ-788 alone cannot inhibit ET-1-induced contractions in human bronchi, although human bronchial ETB receptors are BQ-788-sensitive. Furthermore, it was shown that blockade of both receptor subtypes antagonizes ET-1-induced contraction, and that both receptor subtypes co-exist in human bronchial smooth muscles. These findings suggest that ETA receptors as well as ETB receptors are involved in ET-1-induced contraction in human bronchi. If ET-1 is involved in human airway diseases, dual blockade of ETA and ETB receptors may be necessary to treat the diseases.

Adult↗

PubMed1996

Antigenicity of cell wall mannans of Candida albicans NIH B-792 (serotype B) strain cells cultured at high temperature in yeast extract-containing sabouraud liquid medium.

Cultivation of Candida albicans NIH B-792 (serotype B) at high temperature (37 degrees C) for 48 h in yeast extract-containing Sabouraud liquid medium (YSLM) provided the following findings in comparison with the findings obtained after incubation at 27 degrees C. Growth of the blastoconidia of this strain was decreased, with a dry weight of 9%, and the cells were deficient in cytokinesis. The cells did not undergo agglutination with serum factor 5 from a commercially available serum factor kit (Candida Check). Mannan (B-37-M) obtained from the cells cultured at 37 degrees C had partially lost its reactivity against serum factor 4 and lost most of its reactivity against serum factor 5 in an enzyme-linked immunosorbent assay (ELISA) in contrast to that (B-27-M) at 27 degrees C. Both cells and mannan prepared by cultivation first at 37 degrees C and then at 27 degrees C entirely recovered their reactivities with serum factors 4 and 5. 1H-nuclear magnetic resonance analysis also revealed that B-37-M had lost a beta-1,2-linked mannopyranose unit and retained a phosphate group. Similar changes were observed in the three other serotype B strains used in the study. The beta-1,2-linked mannooligosaccharides longer than mannotetraose were not included among the products released from B-37-M by mild acid treatment. The results of the inhibition ELISA with a series of beta-1,2-linked mannooligosaccharides from biose to octaose (M2 to M8, respectively) showed that the reactivity against serum factor 4 was inhibited most strongly by the oligosaccharides M4 to M8 and that the reactivity against serum factor 5 was inhibited completely by relatively longer oligosaccharides, M5 to M8, indicating their participation as the antigenic factor 5 epitopes.

Agglutination Tests↗