Biomedical subjects

S Nishimura

Publications and source records attributed to S Nishimura.

At least 505 records · Page 28Linked to original sources

PubMed1991

Inhibition of rotavirus and enterovirus infections by tea extracts.

Epigallocatechin gallate from green tea and theaflavin digallate from black tea inhibited infections of cultured rhesus monkey kidney MA 104 cells with rotaviruses and enteroviruses. Their antiviral effects were maximally induced when directly added to virus, and their pre- and post-treatment of the cells produced much weak antiviral activity. Antiviral activity of the extracts therefore seems to be attributable to interference with virus adsorption.

Animals↗

PubMed1991

Two cases of bi-ventricular dysplasia associated with ventricular tachycardia and familial occurrence of sudden death.

Two strikingly similar patients with arrhythmogenic right ventricular dysplasia which severely impaired not only the right ventricle but also the left ventricle are described in association with familial occurrence of sudden death. A 49-year-old man experienced syncope which was due to ventricular tachycardia. Electrocardiography revealed a first degree atrioventricular block, incomplete right bundle-branch block, T wave inversions in leads II, III, a VF and V1 to V5, and multiformal ventricular extrasystoles. Echocardiography and ventricular cineangiography showed not only the right ventricular dilatation with an aneurysm in the right ventricular apex, inflow and outflow tracts, but also mild dilatation of the left ventricle with left ventricular apical and posterior aneurysms. Radionuclide angiography also disclosed dysfunction of both ventricles, especially during exercise. His family history revealed that 3 members of his family died of sudden deaths. A 56-year-old woman experienced syncope secondary to ventricular tachycardia, with left bundle-branch block. Electrocardiography showed complete right bundle-branch block, left axis deviation, and T wave inversions in leads V1 to V4. Echocardiography and ventricular cineangiography revealed not only marked right ventricular dilatation with the "triangle of dysplasia", but also a left ventricular aneurysm in the apex and posterior portion. Her elder brother died of a sudden death, and electrocardiograms of 2 members of her family showed ventricular extrasystoles and T wave inversions. These 2 cases may well be termed "familial bi-ventricular dysplasia".

Cardiac Complexes, Premature↗

PubMed1991

[A case of leiomyoma of the trachea].

An asymptomatic 59-year-old male in whom an abnormal shadow was detected on indirect chest X-ray film, was referred to our hospital for further examination. Further examinations revealed no problem at the previously checked site. However, bronchoscopy revealed a protruding hemispheric lesion on the membranous portion of the trachea 2 cm above the carina. The biopsy specimens revealed that the lesion was leiomyoma of the trachea. Transbronchoscopic biopsy was performed three times and the lesion disappeared. A few small fibrous nodules remained. The incidence of this primary tracheal tumor is rare, and benign lesions are much less common than malignant lesions. Furthermore, leiomyoma of the trachea is extremely rare. Only 20 cases have been reported in Japanese and English literature. The average age of the reported cases, including our case, was 49.3 years old. Among the male patients, most cases were around 50 years old but among female patients, there was no standard age for this disease. Clinical symptoms included coughing, dyspnea, wheezing and bloody sputum. There were several patients with severe dyspnea, two of which died. Ten patients (50%) had been misdiagnosed as having bronchial asthma. If a case is suspected to be bronchial asthma in which and where bronchodilators have little effect, we must always consider the possibility of this type of lesion, and perform further examinations and treatment.

Bronchoscopy↗

PubMed1991

[A study of smoking cessation education in a multiphasic screening setting].

A study of the effectiveness of individual anti-smoking advice was conducted on male smokers visiting a human dock. The intervention group (169 male smokers) were shown photographs depicting the health hazards of smoking with an explanation by tape recorder and headphone. Controls (187 male smokers) did not receive this instruction. In the intervention group, immediately after the instruction, and in the control group, approximately 60% expressed a desire to stop or decrease their smoking. Six months later there was no significant difference in the two groups in the proportion that stated that they were not smoking (8.9% in the intervention group and 5.9% in the control group). Some subgroups in the intervention group, such as those whose smoking index was less than 400 and those who had attempted to quit smoking in the past, had significantly higher quit rates than corresponding subgroups in the controls. Smokers who restricted their smoking in certain locations such as public areas had high quit rates in both groups. Standardized quit rates were utilized, adjusted for current age, age of smoking initiation, smoking index and past experience in smoking cessation. Immediately after receiving the education, the proportion that regarded smoking as a risk factor in gastric cancer, gastric ulcer, chronic bronchitis and as having a harmful effect on the fetus, was significantly larger in the intervention group (about 50-70%) than in the controls (about 30-60%). More than 90% of each group regarded it as a risk factor in lung cancer, and about 60% in myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Natural history of 82 patients with hypertrophic cardiomyopathy: follow-up for over ten years].

The natural courses of 82 patients with hypertrophic cardiomyopathy (HCM) were investigated in follow-up periods of over 10 years (mean follow-up: 11.7 yrs.). Twelve patients had obstructive, 30 non-obstructive and 40 apical HCM. There were 76 males and 6 females. The mean age at the initial diagnosis was 48 years. All patients underwent cardiac catheterization and left ventriculography, and two-dimensional echocardiography was conducted in some patients. To determine the clinical features influencing the prognosis, their serial laboratory and clinical data were reviewed and analyzed. Five patients died of non-cardiac causes. Only one died suddenly. Congestive heart failure developed in 3 patients, 2 with obstructive and one with non-obstructive HCM. Two patients had cavity dilatation and deteriorated ventricular function, and finally exhibited dilated cardiomyopathy-like features. Characteristically, in this deteriorating group, a decrease in the QRS voltage and an abnormal Q wave gradually developed without clinical evidence of myocardial infarction. Two patients with apical HCM in this group had decreases in their QRS voltages and in the depths of their giant negative T waves. They developed apical left ventricular asynergy without myocardial infarction or congestive heart failure. There were no specific clinical or laboratory parameters predictive of sudden death. Atrial fibrillation occurred in 9 patients, resulting in 3 cases of cerebral infarction, one myocardial infarction, and one congestive heart failure. One patient received pacemaker implantation because of the sick sinus syndrome. Three had acute myocardial infarction. Aortocoronary bypass grafting was performed in 3 patients. These results indicate that the good long-term life prognosis of HCM can be expected in all types of HCM. Among the 82 patients, only one died suddenly. However, since the natural history of HCM can take a variety of courses, careful observation is necessary.

Atrial Fibrillation↗

PubMed1991

[A study on thermal regulation disturbance in severely handicapped patients].

Forty-five severely handicapped patients were investigated on body temperature regulation. Poor regulation cases had CT scans showing severe third and lateral ventricle dilatation. Furthermore, in almost all poor regulation cases of perinatal and postnatal onset, CT scans showed extensive low density areas involving the frontal lobe. Electrophysiological studies (sSEP, ABR and blink reflex) could not show definite differences between poor regulation cases and good regulation cases. These findings suggest that hypothalamus, medial forebrain bundle and frontal lobe play important roles in body temperature regulation. On the other hand, perinatal or postnatal onset cases frequently had small body surface areas and low serum creatinine.

Adolescent↗

PubMed1991

[Ultrasonographic delineation of breast cancer and histopathological characteristics].

Sixty-two patients with breast cancer were evaluated as to the relationship between ultrasonographic images and the pathological findings. Gross configuration of breast cancer was evaluated; knobby type was revealed in 53 cases, stellate type in 7, and spiculate type in 2. Percentage of cellular component was measured histologically, and knobby type proved to be rich in cancer cell in the outer part (61.1 +/- 22.0%), but scarce in the inner part (13.5 +/- 17.3%, p less than 0.01). Also the dissociation between the diameter of hypoechoic area on ultrasonogram (1.84 +/- 0.91 cm) and that on the cut-surface of resected specimen (2.38 +/- 0.96 cm, p less than 0.01) was noted. Meanwhile, other types (stellate or spiculate type) had small number of cancer cells not only in the inner part (9.8 +/- 9.5%) but also in the outer part (28.4 +/- 17.2%). Besides, there was no difference between the diameter on ultrasonogram (1.71 +/- 0.71 cm) and that on the cut-surface (1.82 +/- 0.69 cm). These results suggest that ultrasonography can delineate the entirety of diffusely fibrous breast cancer, but can hardly depict the outer part of the lesion which is fibrous in the inner part and cellular in the outer part. Latter phenomenon can be a clue to diagnose breast cancer from the view point of its heterogeneity.

Adenocarcinoma, Scirrhous↗

PubMed1991

[Inflammatory granulomas extending from the sphenoid sinus to the cavernous sinus: report of three cases].

We treated three cases of inflammatory granulomas extending from the sphenoid sinus to the cavernous sinus. Case 1 was that of a 36-year-old male with diplopia and right ptosis. Case 2 was that of a 40-year-old male with frontal headache. Case 3 was that of a 70-year-old female with left impaired vision and frontal headache. In the first case, MRI demonstrated a mass lesion extending from the right half of the sphenoid sinus to the cavernous sinus and retropharyngeal space. In the second case the granuloma extended from the right cavernous sinus to the right retroorbital space. In the last case, MRI demonstrated diffuse Gd-DTPA enhancement of the left cavernous sinus and the left half of the sphenoid sinus. In all cases an operation was performed using the sublabial rhinoseptal approach, and the tumor in the sphenoid sinus was removed. Histological examination revealed an inflammatory granuloma in all 3 cases. In the first case the clinical symptoms improved following administration of glucocorticoids. In the second case the mass in the cavernous sinus decreased in size postoperatively. In the last case, the clinical symptoms gradually improved with administration of antibiotics after surgery. Granuloma of the cavernous sinus is difficult to diagnose, but when a similar pathological lesion coexists in the sphenoid sinus, a definitive diagnosis can be easily made via the sublabial rhinoseptal approach.

Adult↗

PubMed1991

[Non-Hodgkin's lymphoma of the nasal cavity and paranasal sinuses: clinicopathologic study of ten cases].

Ten patients with non-Hodgkin's lymphoma originated in the nasal cavity (four patients) and in the paranasal sinuses (six patients) were treated mainly with irradiation and combination chemotherapy including adriamycin. According to the TNM AJC staging system, four patients were in stage T1-T2, and six patients were in stage T3-T4. Nine patients, other than one with stage IV (Ann Arbor) disease, achieved complete remission. Death due to lymphoma occurred in four patients, 4 to 39 months following diagnosis. Three of these patients developed systemic extranodal dissemination, and died in a short time after relapse. Death due to second malignancies occurred in two patients. One died of acute myelogenous leukemia, and the other died of colon cancer, 26 and 53 months after diagnosis, respectively. Four patients were alive and disease-free, from 23 to 68 months following diagnosis (median 40 months). Out of four patients who died of disease, three were in stage T3-T4, and one was in stage T1. Two patients with stage T1 originated in the nasal cavity were both alive and disease-free. Except for lymphomas with stage T1 originated in the nasal cavity, more intensive chemotherapy should be instituted in an attempt to achieve better disease-free survival.

Adult↗

PubMed1991

[Clinical significance of immunophenotype in diffuse non-Hodgkin's lymphoma: with special emphasis on the clinical characteristics of T-cell lymphoma].

The clinical significance of immunophenotyping of the non-Hodgkin's lymphomas (NHL) is still controversial. Therefore, we evaluated the prognostic significance of T- and B-cell phenotype in 102 patients having diffuse non-Hodgkin's lymphoma who had been treated in a majority with Adriamycin-containing regimens. The significant differences in pretreatment clinical variables between the two patient groups were the higher frequency of markedly elevated LDH (greater than or equal to X 2 normal) and the lower frequency of decreased cholesterol level in B-NHL (p less than 0.05). Patients with B-NHL had a higher complete remission (CR) rate (77% vs 59%: p = NS), a significantly better overall survival (62% vs 34% at 3-years: p less than 0.05) and longer duration of remission for all patients (50% vs 27% at 3-years: p less than 0.05). Among forty-five patients with stages III and IV disease of nodal origin (excluding those with diffuse small cleaved histology), the B-cell group was associated with a better prognosis; a higher CR rate (68% vs 41%: p = NS) and a longer duration of remission for all patients (44% vs 12% at 2-years: p less than 0.05). Furthermore, for patients with T-cell phenotype, the primary site was the only prognostic factor; the patients whose disease originated from Waldeyer's ring, nasal cavity, and paranasal sinuses, achieved a better CR rate (92% vs 40%: p less than 0.05) and a longer duration of remission for all patients (48% vs 15% at 2-years: p less than 0.05). We conclude that advanced T-cell lymphoma of nodal origin is a subgroup of patients with very poor prognosis if treated with less intensive chemotherapeutic regimens.

Adolescent↗

PubMed1990

Excitatory effect of adenosine on neurotransmission in the slices of superior colliculus and hippocampus of guinea pig.

Postsynaptic potential (PSP) was recorded from the CA3 region of the pyramidal cell layer of hippocampal slices and from the superficial gray layer of superior collicular slices from guinea pigs. In the hippocampal slices, application of adenosine to the perfusion medium at a concentration of 10 nM to 1 microM enhanced the amplitude of the PSP and at concentrations greater than 10 microM it depressed the PSP. The dose-response curve of the effect of adenosine on neurotransmission in the hippocampus thus showed an excitatory and inhibitory biphasic pattern according to the concentrations applied. However, in superior collicular slices, application of adenosine at concentrations of more than 10 nM enhanced the amplitude of the PSP and there was no inhibition by adenosine even at a concentration of 1 mM.

Adenosine↗

PubMed1990

Synthesis of a peripheral trisaccharide sequence of lutropin, a pituitary glycoprotein hormone; use of chitobiose as a key starting material.

A chitobiose derivative, methyl O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl)-(1--- -4)-3,6 - di-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranoside, was derived from the corresponding N-acetyl derivative and this was converted into the glycosyl bromide (5). Glycosidation reaction between 5 and methyl 3,4,6-tri-O-benzyl-alpha-D-mannopyranoside in the presence of silver trifluoromethanesulfonate gave a beta-D-linked trisaccharide derivative. Replacement of the N,N-phthaloyl group by acetyl groups resulted in a product that was converted into methyl O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranosyl)-(1----4)-O -(2- acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranosyl)-(1----2)-3,4,6- tri-O- benzyl-alpha-D-mannopyranoside (11) by use of a few reaction steps. The 4(3)-hydroxyl group of 11 was methanesulfonylated, and the product subjected to SN2 replacement with acetate anion, to give the D-galactosamine-containing trisaccharide derivative (12). After basic hydrolysis of 12, the 4(3)-hydroxyl group was sulfated, and all benzyl groups were removed by hydrogenolysis, giving methyl O-(2-acetamido-2-deoxy-4-O-sulfo-beta-D-galactopyranosyl)-(1----4)-O-(2- acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----2)-alpha-D-mannopyranosid e monosodium salt, the methyl alpha-glycoside derivative of the peripheral trisaccharide sequence of the pituitary glycoprotein hormone lutropin.

Carbohydrate Sequence↗

PubMed1990

Excitatory and inhibitory effects of adenosine on the neurotransmission in the hippocampal slices of guinea pig.

Postsynaptic potentials (PSPs) were recorded from the granular cell layer of guinea pig hippocampal slices. Application of adenosine at a concentration of more than 10 microM in the incubation medium depressed the amplitude of the PSP, but adenosine at a concentration of 10 nM to 1 microM enhanced the amplitude of the PSP. The dose-response curve of the effect of adenosine showed an excitatory and inhibitory biphasic pattern. Adenosine analogues such as adenosine triphosphate (ATP), adenosine diphosphate (ADP) and nicotinamide adenine dinucleotide (NAD) showed similar biphasic effects, however beta-gamma-methyleneadenosinetriphosphate (beta-gamma-ATP), 5'-N-ethylcarboxamidoadenosine (NECA). N6-cyclohexyladenosine (CHA) and N6-R-phenylisopropyladenosine (RPIA) revealed only inhibitory effects.

Adenosine↗

PubMed1990

An F factor based cloning system for large DNA fragments.

An effective technique using an Escherichia coli plasmid system was developed to clone fragments of exogenous DNA of as large as 100 kilobase pairs. The characteristic features of this technique are the use of a low copy number (one to two) mini-F based plasmid vector and the introduction of artificial lambda cosR ends into the termini of DNA sources and then of the cosL ends into those of linearized vector molecules. This terminal modification greatly facilitated the formation of active large recombinant molecules, which was rarely achieved when the modification was omitted. The efficiency with which large recombinant clones can be generated is high enough to allow construction of a comprehensive library of higher organisms. All analyses of the plasmids recovered have revealed that the inserts were faithful replicas of the human DNAs used as sources.

Base Sequence↗

PubMed1990

Efficient integrative transformation of the phytopathogenic fungus Alternaria alternata mediated by the repetitive rDNA sequences.

An attempt was made to transform Alternaria alternata protoplasts using a plasmid vector, pDH25, bearing the Escherichia coli hygromycin B (Hy) phosphotransferase gene (hph) under the control of the Aspergillus nidulans trpC promoter. Transformants arose on a selective medium containing 100 micrograms Hy/ml. There were two types of transformants, forming large and small colonies on the selective medium. Transformation with one microgram of the vector produced an average of 4.5 large colonies and 600 small ones. In large-colony transformants, the vector often integrated into the recipient chromosome in the form of highly rearranged tandem arrays. To increase transformation efficiency, fragments of the highly repetitive ribosomal RNA gene cluster (rDNA) of A. alternata were used to construct four new vectors for homologous recombination system. Use of these vectors gave higher transformation efficiency than the original plasmid. The best vector, pDH25r1a, gave rise to large-colony transformants at a frequency 20 times higher than pDH25. Transformation events in A. alternata with pDH25r1a occurred by homologous recombination as a single crossover between the plasmid-borne rDNA segment and its homologue in the chromosome, often giving rise to tandemly repeated vector DNA.

Alternaria↗

PubMed1990

Infrared spectra of phospholipid membranes: interfacial dehydration by volatile anesthetics and phase transition.

Fourier-transform infrared attenuated total reflection (ATR) spectroscopy was used to study the effect of volatile anesthetics on fully hydrated dipalmitoylphosphatidylcholine (DPPC) vesicle membranes. The main phase transition was monitored by the change in the C-H2 asymmetric stretching frequencies of the lipid tails. The surface property was analyzed by the changes in the P = O stretching, (CH3)3-N+ stretching of the hydrophilic head, and C = O stretching of the glycerol skeleton. The partial pressures of those agents that decreased the transition temperature 1.0 C degree were halothane 0.75, enflurane 1.90 and CCl4 0.85 kPa. At a 2:1 lipid/anesthetic mole ratio, the polar anesthetics, halothane and enflurane, increased the ratio of (P = O stretching band area)/((CH3)3-N+ stretching band area) by 26.3% and 21.1%, respectively, whereas apolar CCl4 increased it 10.5%. The water molecules bound to the P = O moiety are apparently replaced by the anesthetic molecules. The deconvoluted C = O spectra showed two peaks: free sn-1 that is closer to the lipid core and hydrogen-bonded sn-2 that is closer to the polar head. Addition of halothane and enflurane, but not CCl4, increased the number of peaks to three. The third peak is free sn-2, formed by disrupting hydrogen-bonding to water. Because the temperature-induced spectral change was limited to C-H2 stretching at the main phase transition, the effects of anesthetics on the lipid membrane structure are not identical to temperature elevation. Among anesthetics, the effects of apolar and polar molecules on the interfacial properties are different.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1990

Molecular switch for signal transduction: structural differences between active and inactive forms of protooncogenic ras proteins.

Ras proteins participate as a molecular switch in the early steps of the signal transduction pathway that is associated with cell growth and differentiation. When the protein is in its GTP complexed form it is active in signal transduction, whereas it is inactive in its GDP complexed form. A comparison of eight three-dimensional structures of ras proteins in four different crystal lattices, five with a nonhydrolyzable GTP analog and three with GDP, reveals that the "on" and "off" states of the switch are distinguished by conformational differences that span a length of more than 40 A, and are induced by the gamma-phosphate. The most significant differences are localized in two regions: residues 30 to 38 (the switch I region) in the second loop and residues 60 to 76 (the switch II region) consisting of the fourth loop and the short alpha-helix that follows the loop. Both regions are highly exposed and form a continuous strip on the molecular surface most likely to be the recognition sites for the effector and receptor molecule(or molecules). The conformational differences also provide a structural basis for understanding the biological and biochemical changes of the proteins due to oncogenic mutations, autophosphorylation, and GTP hydrolysis, and for understanding the interactions with other proteins.

Binding Sites↗

PubMed1990

Tetraethylammonium stimulates adrenomedullary secretion by causing fluctuations in a cytosolic free Ca concentration.

Tetraethylammonium (TEA) caused marked fluctuations in a cytosolic free Ca concentration, which was measured by fura-2 microfluorimetry in bovine adrenal chromaffin cells. At the same time. TEA stimulated catecholamine secretion from cat and bovine chromaffin cells. Present results suggest that TEA indirectly increases the Ca2+ influx by depolarizing the cell membrane and consequently stimulates catecholamine secretion.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗