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Biomedical subjects

Y Nakata

Publications and source records attributed to Y Nakata.

At least 37 records · Page 2Linked to original sources
PubMed2001

Genetic analysis of a variant luteinizing hormone in an infertile woman.

In a woman with infertility and an endometrial polyp, we analyzed the nucleotide sequence of the beta-subunit of her luteinizing hormone which showed anomalous immunogenecity in that it was recognized by time resolved-fluoroimmunoassay but not by immunoradiometric assay. The sequence analysis showed two substitutional mutations of beta-subunit Trp (TGG) to Arg (CGG) and Ile (ATC) to Thr (ACC). The variant luteinizing hormone might have had some relation to the infertility and the endometrial polyp. been described [2, 4, 13-15]. Although the role of the variant LH is still unclear, it has different biologicl activity as compared to normal LH and may play a role in causing infertility, menstrual disorder, endometriosis and spontaneous miscarriage [1, 3, 4, 9, 10, 17]. We now report a study of the DNA sequence of beta-subunit of anomalous LH in an infertile patient with an endometrial polyp.

Adult↗
PubMed2001

Changes in atrial natriuretic peptide and brain natriuretic peptide associated with hypobaric hypoxia-induced pulmonary hypertension in rats.

Experimental pulmonary hypertension induced in a hypobaric hypoxic environment (HHE) is characterized by structural remodeling of the heart and pulmonary arteries. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) both have diuretic, natriuretic, and hypotensive effects, and both are involved in cardiovascular homeostasis as cardiac hormones. To study the effects of HHE on the natriuretic peptide synthesis system, 170 male Wistar rats were housed in a chamber at the equivalent of the 5500-m altitude level for 1-12 weeks. After 1 week of HHE, pulmonary arterial pressure was significantly raised, and the ratio of left ventricle plus septum over right ventricle of the heart showed a significant decrease (compared with those of ground-level control rats). In both ventricular tissues, the expression of ANP messenger (m)RNA and BNP mRNA increased after exposure to HHE. The amounts of ANP and BNP had decreased significantly in right atrial tissue at 12 weeks of HHE (compared with those of the controls), whereas in ventricular tissues at the same time point, both levels had increased significantly. In in situ hybridization and immunohistochemical studies, the staining of the mRNAs for ANP and BNP and of ANP and BNP themselves was more intense in both ventricular tissues after exposure to HHE than before (i.e., in the controls). The results suggest that, in response to HHE, the changes in ventricular synthesis are similar for ANP and BNP. These changes may play a role in modulating pulmonary hypertension in HHE. However, under our conditions, pulmonary hypertension increased progressively throughout the HHE period.

Altitude Sickness↗
PubMed2001

Developmentally regulated expression of brain-specific chondroitin sulfate proteoglycans, neurocan and phosphacan, in the postnatal rat hippocampus.

Developmental changes in the distribution of brain-specific chondroitin sulfate proteoglycans, neurocan and phosphacan/RPTPzeta/beta, in the hippocampus of the Sprague-Dawley rat were examined using monoclonal antibodies 1G2 and 6B4. The 1G2 immunoreactivity was predominant in the neonatal hippocampus while the 6B4 immunoreactivity was predominant in the mature hippocampus. Moderate 1G2 immunoreactivity was detected in the dentate gyrus and subiculum immediately after birth. Immunoreactivity reached a peak on postnatal days 7-10 (P7-P10) when intense 1G2 labeling was present throughout the neuropil layers of the hippocampus except the mossy fiber tract. 6B4 immunoreactivity was limited in the stratum lacunosum moleculare of CA1 in the neonatal hippocampus. It gradually increased by P21 when diffuse 6B4 immunoreactivity was detected in the stratum oriens and radiatum of Ammon's horn, and in the hilus and inner one-third molecular layer of the dentate gyrus, while 1G2 immunoreactivity decreased after P21. In the adult hippocampus, moderate 6B4 immunoreactivity was present in the stratum oriens and radiatum of Ammon's horn, and in the hilus and inner one-third molecular layer of the dentate gyrus, but not in the mossy fiber tract. In addition, strong 6B4 labeling appeared around a subset of neurons after P21. The results suggest that neurocan may have a role in the development of neuronal organization, while phosphacan/RPTPzeta/beta may contribute to the maintenance and plasticity of synaptic structure and function. Furthermore, the absence of 1G2 and 6B4 immunoreactivities in the stratum lucidum suggests that neurocan and phosphacan/RPTPzeta/beta may function as a barrier for the extension of mossy fibers and provide an environment permissive for fasciculation of the mossy fibers.

Animals↗
PubMed2001

Screening for deletions in interval D16-22 of the Y chromosome in azoospermic and oligozoospermic Japanese men.

The genetic basis of infertility remains unclear in a majority of infertile men. In this study, the Y chromosome long arm involving the DAZ (deleted in azoospermia) gene was screened in order to evaluate the occurrence of microdeletion in Japanese infertile men. One hundred and fifty-seven infertile Japanese men with azoospermia and oligozoospermia were analyzed for microdeletions in interval D16-22 of the Y chromosome, using polymerase chain reaction with sequence-tagged site markers. Sixteen sets of oligonucleotide primers were synthesized for the polymerase chain reaction, and Southern blot analysis was also performed. The men were divided into five categories on the basis of sperm concentration: functional azoospermia (A; n = 24), azoospermia caused by obstruction (AO; n = 20), oligozoospermia I (OI, sperm concentration less than I x 10(5)/ml; n = 33), oligozoospermia II (OII, sperm concentration less than 1 x 10(6)/ml; n = 30), and oligozoospermia III (OIII, sperm concentration less than 1 x 10(7)/ml; n = 50). Thirty fertile men with a sperm concentration of more than 2 x 10(7)/ml were also analyzed as controls. Microdeletions were identified, in 12 (7.6%) of the 157 infertile men, as follows: 1 man in category A, 1 in category AO, 5 in category OI, 4 in category OII, and 1 in category OIII. No deletion was identified in the fertile men. One common region around sY240 was identified in 11 of the infertile men with microdeletions. This locus may contain specific genes for spermatogenesis. The sperm concentration in the ten oligozoospermic men with microdeletions was below 1 x 10(6)/ml. There were no correlations between the severity of spermatogenic defects and the extent of the microdeletions. These results suggested that genes in the interval D16-22 of the Y chromosome might have important roles in spermatogenesis.

Base Sequence↗
PubMed2001

Analysis for microdeletions of Y chromosome in a single spermatozoon from a man with severe oligozoospermia.

Since the association between Y chromosome deletions and spermatogenic failure was demonstrated in 1976, there have been many reports of Y chromosome microdeletions. Peripheral blood lymphocytes (PBLs) have been used for the analysis because the method is convenient, materials are easy to obtain, and PBL genomic DNA is similar to that of germ cells such as spermatozoa. However, PBLs originate from somatic tissue, not from germ cells. In this study, we analyzed 30 spermatozoa in semen ejaculated by an infertile male with Y chromosome microdeletions, while 50 spermatozoa from a normal fertile male were used as a control. The same Y chromosome microdeletion as that found in PBL was identified in each of the 12 spermatozoa which contained the Y chromosome in the infertile patient. These results indicated that spermatozoa (germ cells) had the same Y chromosome microdeletion as PBL (somatic cells). This supports the conjecture that microdeletions are transmitted to the next generation via the treatment of infertility by intracytoplasmic sperm injection.

Base Sequence↗
PubMed2001

Electrochemical oxidation of bisphenol A. Application to the removal of bisphenol A using a carbon fiber electrode.

The electrochemical behavior of bisphenol A was investigated by voltammetric techniques. The electrochemical oxidation of bisphenol A led to the inactivation of the glassy carbon electrode as the result of the deposition of the electropolymerized films. Although phenolate is oxidized more easily than the neutral phenol, an electropolymerized film of bisphenol A was formed in neutral media rather than in alkaline media. The fouling of the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferrocyanide ion as the redox marker. The electrochemical removal of bisphenol A based on the formation of the electropolymerized film on an anode surface was also attempted using a carbon fiber electrode with a very large surface area. The high removal efficiency for bisphenol A was obtained in a dilute solution of bisphenol A. The maximum surface coverage (gamma) of electropolymerized bisphenol A on the carbon fiber was about 2 x 10(-9) mol/cm2.

Benzhydryl Compounds↗
PubMed2001

Effect of acute lipopolysaccharide administration on (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane-induced wet dog shake behavior in rats: comparison with body weight change and locomotor activity.

1. Several reports have shown that serotonin (5-HT)2A receptor density and its function are altered after physiological or pharmacological stress. To examine whether an acute administration of lipopolysaccharide (LPS), a bacterial endotoxin, affected 5-HT2A receptor function, wet dog shakes of male Wistar rats were observed after a subcutaneous injection of DOI, a 5-HT2A receptor agonist following LPS treatment. Body weight change and locomotor activity were also observed. 2. DOI (1 mg/kg)-induced WDS significantly decreased after 400 or 1000 microg/kg LPS treatment compared with that of control rats 1 and 3 hr after injection, and WDS completely recovered 8 hr after LPS treatment. Treatment with 10 mg/kg indomethacin (IND) or 1 mg/kg naltrexone (NLTX) canceled the effect of 400 microg/kg LPS on DOI-induced WDS. 3. Body weight decrease was significantly greater in LPS-treated rats compared with control rats 3, 5 and 8 hr after treatment. Treatment with IND (10 mg/kg) significantly recovered the reduction in body weight induced by 400 microg/kg LPS. Treatment with NLTX (1 mg/kg) also prevented the LPS effect on body weight decrease. 4. Eight hr after treatment with LPS (400 microg/kg), the rats showed significant attenuation of locomotor activity. IND (10 mg/kg) treatment abolished the inhibitory effect of LPS on locomotor activity, and NLTX (1 mg/kg) also improved the decrease in locomotion 8 hr after LPS treatment. 5. Plasma tumor necrosis factor (TNF)-alpha concentration dramatically increased 1 hr after the injection of 400 microg/kg LPS, and returned almost to the basal level 3 hr later. Next, rats were injected with 50 microg/kg TNF-alpha intraperitoneally, and body weight change and DOI-induced WDS was determined 3 hr after TNF-alpha injection. Body weight loss was significantly greater in rats treated with TNF-alpha. On the other hand, DOI-induced WDS was not altered when rats were treated with TNF-alpha. 6. These results suggest that acute treatment with LPS inhibited 5-HT2A receptor-mediated behavior via cyclooxygenase and opioid receptor activation, but that the inhibition of the WDS by LPS appears to be independent of TNF-alpha production.

Amphetamines↗
PubMed2001

An autopsy case of pancreatic and ectopic nesidioblastosis.

We report an autopsy case of pancreatic and ectopic nesidioblastosis. A five-month-old Japanese girl was born at 35 weeks gestation, and showed clinical symptoms of hyper-insulinemic hypoglycemia before death. At autopsy a tumorous nodule was observed at the portion of the jejunum, 90 cm from Treitz's ligament. The nodule measured 30 x 20 x 20 mm. The ectopic pancreas, also revealed nesidioblastosis histologically. Immunohistologically, both nesidioblastoses were stained positive for chromogranin A, insulin, glucagon and somatostatin. The proliferating cell nuclear antigen (PCNA) and Ki-67 indices were less than 4% in the nesidioblastosis. To our knowledge, this is the first reported case of nesidioblastosis demonstrating proliferating activity with PCNA and Ki-67, and is the third reported case of nesidioblastosis arising in the pancreas and ectopic pancreas.

Choristoma↗
PubMed2001

Prediction of difficult airway in school-aged patients with microtia.

BACKGROUND: Because the ear and mandible develop from the first and second branchial arches and first branchial cleft, abnormalities of the ear may be a sign that intubation will be difficult. We hypothesized that children with microtia would have a greater incidence of difficult laryngeal visualization with conventional rigid laryngoscopy compared to those with normal facial anatomy. METHODS: We enrolled 93 consecutive school-aged patients with microtia undergoing the first stage of total reconstruction of the auricle. Age-matched patients with normal facial anatomy served as controls. Each patient was examined for the presence or absence of the five dysmorphic features of hemifacial microsomia: orbital asymmetry, mandibular hypoplasia, ear deformity, nerve involvement, soft tissue deficiency (OMENS classification). After a standardized induction of anaesthesia, the laryngeal view during rigid laryngoscopy was graded. RESULTS: The incidence of difficult laryngeal view was 42% in the patients with bilateral microtia, 2% in those with unilateral microtia and 0% in the controls. CONCLUSIONS: There was a strong positive correlation between the number of involved abnormal anatomical components according to the OMENS classification and the degree of difficult visualization of the larynx in patients with both bilateral and unilateral microtia (Spearman rank order correlation coefficient=0.85 and 0.88, respectively).

Adolescent↗
PubMed2001

Characteristic association between K-ras gene mutation with loss of heterozygosity in X-ray-induced thymic lymphomas of the B6C3F1 mouse.

PURPOSE: To elucidate the characteristics of radiation carcinogenesis, the spectra of K- and N-ras oncogene mutations, loss of heterozygosity (LOH) and their association in X-ray-induced thymic lymphomas (TL) were determined by comparing with those of N-ethyl-N-nitrosourea (ENU)-induced and spontaneously occurring TL. MATERIALS AND METHODS: TL that arose in untreated, X-ray-irradiated and ENU-treated B6C3F1 mice were examined both for K- and N-ras mutations by PCR-SSCP and DNA sequencing and for LOH by PCR with polymorphic microsatellite markers. RESULTS: (1) ras gene mutations were found in a proportion of TL from X-ray-exposed (approximately 20%) and ENU-treated (30-40%) mice while no ras gene mutations were found in spontaneous TL. N-ras mutations were rare. (2) The spectrum of ras gene mutations was diverse and seemed to differ little between X-ray-induced and ENU-induced TL, even though there was a higher frequency of ras mutations in ENU-induced TL that clustered to K-ras codon 12. (3) The X-ray-induced TL showing K-ras mutation were associated with LOH on chromosome 6, while those showing no K-ras mutation were associated with high frequency of LOH on chromosomes 4, 11 and 12. CONCLUSION: These results demonstrate that, in the B6C3F1 mouse TL, X-ray-induced lymphomagenesis showed both the co-expression, yet low occurrence of allelic imbalance on chromosome 6 and K-ras mutation, and exclusive expression of frequent allelic imbalance on chromosomes 4, 11 and 12 and K-ras mutation.

Animals↗
PubMed2001

Minimum alveolar concentration (MAC) of xenon with sevoflurane in humans.

BACKGROUND: Although more than 30 yr ago the minimum alveolar concentration (MAC) of xenon was determined to be 71%, that previous study had technological limitations, and no other studies have confirmed the MAC value of xenon since. The current study was designed to confirm the MAC value of xenon in adult surgical patients using more modern techniques. METHODS: Sixty patients were anesthetized with sevoflurane with or without xenon. They were randomly allocated to one of four groups; patients in group 1 received no xenon, whereas those in groups 2, 3, and 4 received end-tidal concentrations of 20, 40, and 60%, respectively (n = 15 each group). Target end-tidal sevoflurane concentrations were chosen using the "up-and-down" method in each group. After steady state sevoflurane and xenon concentrations were maintained for at least 15 min, each patient was monitored for a somatic response at surgical incision. Somatic response was defined as any purposeful bodily movement. The MAC of sevoflurane and its reduction by xenon was evaluated using the multiple independent variable logistic regression model. RESULTS: The interaction coefficient of the multiple variable logistic regression was not significantly different from zero (P = 0.143). The MAC of xenon calculated as xenon concentration that would reduce MAC of sevoflurane to 0% was 63.1%. CONCLUSIONS: The authors could not determine whether interaction in blocking somatic responses in 50% of patients is additive. The MAC of xenon is in the range of the values that were predicted in a previous study.

Adult↗
PubMed2001

The midlatency auditory evoked potentials predict responsiveness to verbal commands in patients emerging from anesthesia with xenon, isoflurane, and sevoflurane but not with nitrous oxide.

BACKGROUND: It has recently been demonstrated that the approximately 40-Hz spectral power of the midlatency auditory evoked potential (MLAEP) correlates well with wakefulness during desflurane or propofol anesthesia. The aim of this study was to characterize how other inhalational anesthetics affects the MLAEP as the patients regain responsiveness to simple verbal command during emergence from anesthesia. METHODS: Sixty patients were randomly assigned to receive xenon, isoflurane, sevoflurane, or nitrous oxide (N2O) supplemented with epidural anesthesia. During emergence, the concentration of an anesthetic was decreased in 0.1-minimum alveolar concentration (MAC) decrements from 0.8 MAC or from 70% in the case of N2O, and each new concentration was maintained for 15 min. Every 5 min during each equilibration period, the MLAEP was recorded and the patients were asked to open their eyes and squeeze and release the investigator's hand. This process was repeated until the first response to either of these commands was observed. RESULTS: Thirteen patients were excluded because of technical reasons. The preanesthetic MLAEP showed a periodic waveform, where the Na-Pa-Nb complex was the most prominent component contributing to the high energy around 29-39 Hz in the power spectrum. Emergence from xenon, isoflurane, and sevoflurane anesthesia produced similar changes in the MLAEP. The spectral power for the frequency 29 Hz or greater was severely suppressed at 0.8 MAC but significantly recovered between the concentration only 0.1 MAC higher that permitting the first response to command and that associated with the first response. In contrast, N2O hardly affected the MLAEPs, even at the concentrations producing unresponsiveness. Two patients did not lose responsiveness even at the highest concentration tested (70%). CONCLUSIONS: The MLAEP is closely associated with responsiveness to verbal command during emergence from anesthesia with xenon, isoflurane, and sevoflurane but not with N2O.

Adult↗
PubMed2001

Triangulation and adolescent development in the U.S. and Japan.

Using an indirect measure of family structure, relationships between parents and adolescents were studied in 99 U. S. and 60 Japanese families. As two-person relationships tend toward instability under stress, a third person may be drawn in to stabilize the system. Parents, for example, may avoid the tension in the marital relationship by focusing together on an adolescent's problem, or pull the adolescent into a coalition with one parent. Either way the parents are said to have "triangled" the adolescent. In this study, a relationship is found between parents avoiding tension in their own relationship and their tendency to triangle an adolescent. Triangled daughters, in both cultures, had lower scores on ego development, supporting the hypothesis that such patterns can be detrimental to the adolescent's personal development. The discussion includes comments on cross-cultural research.

Adolescent↗
PubMed2001

ST segment elevation in the right precordial leads following administration of class Ic antiarrhythmic drugs.

Electrocardiographic changes were evaluated retrospectively in five patients without previous episodes of syncope or ventricular fibrillation who developed abnormal ST segment elevation mimicking the Brugada syndrome in leads V1-V3 after the administration of class Ic antiarrhythmic drugs. Pilsicainide (four patients) or flecainide (one patient) were administered orally for the treatment of symptomatic paroxysmal atrial fibrillation or premature atrial contractions. The QRS duration, QTc, and JT intervals on 12 lead surface ECG before administration of these drugs were all within normal range. After administration of the drugs, coved-type ST segment elevation in the right precordial leads was observed with mild QRS prolongation, but there were no apparent changes in JT intervals. No serious arrhythmias were observed during the follow up periods. Since ST segment elevation with mild QRS prolongation was observed with both pilsicainide and flecainide, strong sodium channel blocking effects in the depolarisation may have been the main factors responsible for the ECG changes. As the relation between ST segment elevation and the incidence of serious arrhythmias has not yet been sufficiently clarified, electrocardiographic changes should be closely monitored whenever class Ic drugs are given.

Aged↗