Biomedical subjects

M Nishimura

Publications and source records attributed to M Nishimura.

At least 1,045 records · Page 58Linked to original sources

PubMed1990

[Clinical investigation on the involvement of an endogenous digitalis-like substance in blood pressure regulation].

We assessed the role of circulating digitalis-like substance(s) on the blood pressure regulation in patients with essential hypertension, cardiac diseases, diabetes mellitus and renal diseases by measuring digoxin-like immunoreactivity (DLI). Plasma DLI concentrations tended to correlate with blood pressure in all patient groups. Plasma DLI correlated to plasma aldosterone concentration in patients with essential hypertension, which suggested close interrelationship between DLI and electrolytes metabolism with adrenal steroids. Serum immunoreactive insulin (IRI) levels significantly correlated with blood pressure. Because plasma DLI levels correlated with serum IRI, increased levels of insulin could have induced sodium retention leading to increased DLI levels. Digitalis-like substance, but not insulin, would have directly increased blood pressure in patients with abnormal glucose tolerance. Plasma DLI levels significantly correlated with the severity of renal insufficiency in patients with renal diseases. Plasma DLI highly correlated with amounts of plasma proteins, particularly with albumin, which would be due to the binding of DLI with albumin in plasma. Because the level of non-binding DLI is extremely low when assayed with a digoxin-radioimmunoassay, it was impossible to assess the level of a free-form of DLI, i.e., active DLI. That could be a reason why the correlation between the DLI and the other parameters was not highly significant. Collectively, these findings suggest that the DLI is one of the major determinants of blood pressure rises, regardless of any cause.

Adult↗

PubMed1990

[Tracheal dimensions in young twins].

Tracheal dimensions were analyzed radiographically in 17 pairs of healthy high school boys (12 pairs of monozygotic twins and 5 pairs of dizygotic twins). Coefficients of variation in interindividual extra- and intrathoracic tracheal widths, tracheal depth, tracheal length, and cross sectional area ranged from 9.6 to 17.3%. Genetic influence was found in intrathoracic as well as extrathoracic tracheal widths at maximal expiration and in extrathoracic tracheal width at maximal inspiration. Intrathoracic tracheal width remained the same at either maximal inspiration or expiration. However, extrathoracic tracheal width became larger at maximal inspiration regardless of great changes in pleural pressure. These results indicate that tracheal rings may be influenced by genetic factors and that extrathoracic width may be enlarged during maximal inspiration.

Adolescent↗

PubMed1990

[Optimal perfusion criteria for deep hypothermic selective cerebral perfusion in patients with aortic aneurysm involving aortic arch].

Although selective cerebral perfusion (SCP) might be an useful supportive method for aortic arch surgery, its optimal perfusion criteria has not been established. We studied the relationship between the oxygen saturation of superior vena cava or internal jugular vein (SvO2) and the perfusion hemodynamics during deep hypothermic (DH) SCP in twenty patients (pts) (type A dissection; 10, arch aneurysm; 10). SCP was accomplished by perfusion to the brachiocephalic trunk (BCT) and the left common carotid artery (LCC) using separate pumps. Cardiopulmonary bypass and DHSCP time were 128-312 (222 +/- 43, mean +/- SD) minutes and 25-214 (122 +/- 49) minutes, respectively. The cerebral perfusion pressures (CPP) monitored at the bilateral temporal arteries were 20-60 (47 +/- 9) mmHg and cerebral perfusion flow (CPF) was 0.28-0.7 (0.43 +/- 0.10) L/min/m2. The cerebral perfusion score (CPS) defined as CPP X CPF was 7-39 (20 +/- 8). SvO2 ranged from 79 to 99 (94 +/- 7)%. Two operative deaths were encountered from unrelated causes to SCP in both cases. Cerebral infarction occurred in one patient possibly form prolonged low perfusion with low SvO2. When the safety range of SvO2 in DHSCP was defined as greater than 90%, essential criteria to keep this range was CPP greater than 40 mmHg. In 13 out of 15 pts with SvO2 greater than 90%, CPS were above 15. In conclusion, optimal perfusion criteria for DHSCP was defined as CPP greater than 40 mmHg and CPS(CPP X CPF) greater than 15 considering adequate cerebral oxygen consumption.

Adult↗

PubMed1990

Experimental gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

MNNG-induced experimental gastric cancer developed in the pyloric glandular region. Many of the tumors produced were well or moderately differentiated adenocarcinomas of elevated type. According to the degree of depth invasion, a majority of the tumors were classified as early-stage lesions invading within submucosal layer. There were two poorly differentiated lesions, which were both recognized as serosal neoplastic involvements. The tumors were positively stained by toluidine blue (pH 4.1) to indicate the presence of stroma. The Brdu-LI determined for gastric mucosal epithelial cells was significantly higher in the MNNG-treated group than in the untreated control group. However, the LI for cancer tissue in the MNNG-treated group did not significantly differ from that for gastric mucosa in the same group.

Animals↗

PubMed1990

[Measurement of flow-resistive work of heat and moisture exchangers during simulated active breathing].

The performance of seven commercially available heat and moisture exchangers (HME) was evaluated in the dynamic flow state. A piston pump was used as a simulator with operative conditions with stroke volume of 500 ml and with respiratory rates of 20 and 40 cycles.min-1. A pressure-volume loop was produced for each HME and the flow-resistive work calculated. Each HME was studied under both dry and wet conditions. It was found that the flow-resistive work of the Humid-Vent 2 was the smallest and that of the Breathaid the largest under both conditions. The results suggest that application of HME causes a significant increase in resistance and demands a greater breathing effort from patients. Its use should thus be avoided in marginal patients.

Anesthesiology↗

PubMed1989

Ionic mechanisms of the depression of automaticity and conduction in the rabbit atrioventricular node caused by hypoxia or metabolic inhibition and protective action of glucose and valine.

The effects of hypoxia and a metabolic inhibitor, sodium cyanide (NaCN), on the spontaneous action potential and membrane current systems were studied in small preparations (0.2 x 0.2 x 0.1 mm) of rabbit atrioventricular node. When the PO2 of the superfusate was lowered from 500 to less than 20 mm Hg, all the preparations initially showed reductions in the spontaneous firing frequency (due to the decreased rate of diastolic depolarization) and maximal rate of depolarization, which were followed by a cessation of automatic activity with subsequent membrane hyperpolarization to -57 +/- 3 mV (n = 4). Voltage clamp experiments using double microelectrode techniques revealed that hypoxia reduced the slow inward current by 20 to 80% without affecting its inactivation kinetics. The delayed rectifying potassium current tail was also reduced or abolished by severe hypoxia, whereas the background outward current was greatly increased. The hyperpolarization-activated inward current was decreased by hypoxia. Similar changes in the spontaneous action potential and membrane currents were obtained on adding 0.1 to 0.5 mM NaCN to the superfusate under conditions of normal PO2. Hypoxia-induced suppression of automaticity was reversed completely by 5 mM glucose, and partially by 40 mM valine. These results suggest that (1) hypoxia impairs atrioventricular nodal conduction by reducing the slow inward current and the delayed rectifying potassium current; (2) hypoxia depresses automaticity by increasing the background outward current and, to some extent, by reducing the slow inward current; and (3) glucose and valine contribute to the generation of high-energy phosphates in cytoplasm and mitochondria, respectively, and protect the atrioventricular node from hypoxia.

Action Potentials↗

PubMed1989

[Estrogen receptor status and expression of carbohydrate antigens in breast cancer].

Seventy-six cases of primary cancer of the breast were studied by clinicopathological examination and immunohistological examination using monoclonal antibodies. They were composed of 40 cases positive for estrogen receptor (ER) and 36 cases negative for ER, the ER-positive rate being 52.6%. ER was detected more frequently in the postmenopausal group than in the premenopausal group, though the ER-positive rate was not significantly different between the two groups. The disease was advanced with a large tumor (greater than t3) and high-grade lymph node metastasis in ER-negative cases compared with ER-positive cases. The carbohydrate antigens specific to SPan-1, CA 19-9 and SLEX were found in 34.2%, 39.5% and 68.4% of the cases studied, respectively. These antigens were detected more often, if not significantly, in cases with a large mass and high-grade metastasis than in those with a small mass and without metastasis or with low-grade metastasis. The SPan-1-positive rate was significantly higher in ER-negative cases graded t1 or t2 than in ER-positive cases falling under the same category of tumor size. Significant differences were also noticed between the ER-negative and ER-positive groups with respect to CA 19-9-positive rate (t2 category) and SLEX-positive rate (t3 category). Similar data were obtained when our cases were classified by the degree of lymph node metastasis. In consequence, the present observations suggested that the expression of carbohydrate antigens in primary breast cancer and disease progress might be correlated with ER status.

Adult↗

PubMed1989

Kinetic study of the reaction of vitamin C with vitamin E radicals (tocopheroxyls) in solution.

New stable vitamin E radicals (7-tert-butyl-5-isopropyltocopheroxyl (4), 5,7-diisopropyltocopheroxyl (5), 7-tert-butyl-5-methyltocopheroxyl (6), and 5,7-diethyltocopheroxyl (7] with two bulky alkyl substituents at ortho positions (C-5 and C-7) have been prepared, and the reaction rates of vitamin C (ascorbic acid (1) and 6-O-stearyl ascorbic acid (2] with these tocopheroxyl radicals in benzene/ethanol/water (2:1:0.1, v/v) solution have been determined spectrophotometrically, using a stopped-flow technique. The second-order rate constants, k2, obtained vary in the order of 10(3), and decrease dramatically in the order 7 greater than 6 greater than 5 greater than 4, as the size of two ortho-alkyl groups in tocopheroxyl increases. The result suggests that the effect of steric hindrance on the reaction rate is considerable. These reaction rates were compared with those of vitamin C with alpha-tocopheroxyl reported by Packer et al. (Nature 278 (1979) 737-738) and Scarpa et al. (Biochim. Biophys. Acta 801 (1984) 215-219).

Ascorbic Acid↗

PubMed1989

Preparation of monoclonal antibodies against methamphetamine.

15 monoclonal antibodies against methamphetamine (MA) were obtained from hybridoma clones by the fusion of mouse 653 myeloma cells with the spleen cells of the immunized mice. The monoclonal antibodies exhibited different cross-reactivities against MA-related compounds and one antibody (MA-15 Ab) was highly specific against MA. A competitive inhibition enzyme-linked immunosorbent assay was established and the detection limit for MA was approximately 20 ng/ml.

Animals↗

PubMed1989

Somatotopic organization of tooth pulp primary afferent neurons in the cat.

Transganglionic transport of horseradish peroxidase-wheat germ agglutinin conjugate (HRP-WGA) was used to study the somatotopic organization of pulpal afferent neurons innervating the different types of teeth in the trigeminal ganglion and trigeminal sensory nuclear complex (TSNC). In separate animals, the upper first 3 incisors (UI1-3), canine (UC), second premolar (UP2) and third premolar (UP3), and the lower first three incisors (LI1-3), canine (LC), first premolar (LP1), second premolar (LP2) and molar (LM) were traced in this experiment. Cell bodies innervating posterior teeth were found with greater frequency in dorsal maxillary ganglion regions, while somata supplying more anterior teeth were predominant ventrally. In contrast, cell bodies innervating the lower teeth were not arranged in a somatotopic fashion in the mandibular subdivision. Each pulpal afferent from lower and upper teeth projected to the subnucleus dorsalis (Vpd) of the pars principalis, the rostrodorsomedial (Vo.r) and dorsomedial parts (Vo.dm) of the pars oralis (Vo), the medial regions of the pars interpolaris (Vi), and laminae I, II, and V of the medullary dorsal horn, and terminal fields between the upper and lower teeth were separated in each subdivision. Pulpal projections from both the upper and lower teeth to each subdivision were organized in a somatotopic manner, while an extensive overlap in projections was noted between the adjoining teeth. In the Vpd, the upper and lower teeth were represented dorsoventrally, and projections from the anterior to posterior teeth in the upper jaw were arranged in both rostrocaudal and ventrodorsal sequences whereas those in the lower jaw were organized caudarostrally and lateromedially. In the Vo.r and Vo.dm, the upper and lower teeth were represented in a mediolateral sequence and projections from the anterior to posterior teeth were organized in a ventrolateral to dorsomedial sequence. In the Vi, pulpal projections were organized in a topographic fashion similar to that observed in the Vo.r and Vo.dm. In the medullary dorsal horn, the upper and lower teeth were represented in laminae I, II and V in a lateromedial sequence. Their projections to laminae I and V were topographically organized in a mediolateral and rostrocaudal sequence.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗

PubMed1989

Adult T-cell leukemia initially manifesting as facial diplegia.

We report an unusual case of adult T-cell leukemia (ATL) initially manifesting as facial palsy due to ATL meningitis, which was caused by lymphoid cells in the cerebrospinal fluid (CSF) with a different phenotype from those in the blood. A DNA southern blot analysis of the blood cells confirmed the diagnosis of ATL. The aberrant cells in the CSF contained nuclei with simple indentations and responded well to the initial chemotherapy, while leukemic cells in the blood showed lobulated or convoluted nuclei and were resistant to treatment. Flow cytometry performed before treatment demonstrated that the majority of the cells in the CSF were CD3+CD4+CD8-CD25+, consistent with ATL, whereas they expressed the CD45R antigen, which the blood ATL cells did not. These differences in the subphenotype, cell morphology, and responsiveness to treatment among the ATL cells in blood and CSF suggest that a single clone or subclone with heterogeneous nature was not generated, before the final development of ATL.

Adult↗

PubMed1989

Restriction fragment length polymorphism analysis of major histocompatibility complex genes in the non-obese diabetic mouse strain and its non-diabetic sister strains.

It has been suggested that one of the recessive genes controlling diabetes in non-obese diabetic mice is linked to the major histocompatibility complex. We, therefore, performed restriction fragment length polymorphism studies of major histocompatibility complex genes (class I, II, and III) in non-obese diabetic mice in comparison with those of their non-diabetic sister strains, non-obese non-diabetic, cataract, and ILI mice which were derived from the same Jcl-ICR mice as the non-obese diabetic mouse was. When class II and III probes and a minimum of four restriction enzymes were used, class II and III genes of non-obese diabetic mice were indistinguishable from those of cataract and ILI mice but totally different from those of non-obese non-diabetic mice. The studies also indicated that A beta, E beta, and C4-Slp genes of non-obese diabetic, cataract, and ILI mice, and A alpha, A beta, E beta and C4-Slp genes of non-obese non-diabetic mice are different from those of BALB/c and C57BL/6 mice, respectively. While non-obese non-diabetic mice expressed the E alpha gene, non-obese diabetic, cataract, and ILI mice appeared to carry a deletion in the 5' end of the E alpha gene resulting in failure to transcribe the E alpha gene. When class I probe was used, cataract mice showed very different band patterns from those of the other ICR-derived mice. It is suggested that non-obese diabetic, non-obese non-diabetic, and ILI mice contain only a single class I D region gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Pharmacokinetics of famotidine in elderly patients with and without renal insufficiency and in healthy young volunteers.

The pharmacokinetics of the H2-receptor antagonist famotidine, after oral administration of a 20 mg tablet, has been studied in 10 elderly patients with normal renal function (CLCR greater than or equal to 59 ml.min-1, Mean = 80 ml.min-1), 5 elderly patients with renal insufficiency (CLCR less than or equal to 38 ml.min-1, Mean = 15 ml.min-1), and 6 healthy young volunteers. Elimination half-life in the elderly patients with renal insufficiency was significantly prolonged compared to the elderly patients with normal renal function and the young volunteers. The correlation coefficient between creatinine clearance and the elimination rate constant of famotidine was 0.672. Mean urinary recovery of unchanged drug up to 24 h in the young volunteers was 44%. The mean renal clearance of famotidine in the young volunteers (270 ml.min-1) was substantially greater than the creatinine clearance, 128 ml.min-1, which suggests the possibility of tubular secretion of famotidine.

Adult↗

PubMed1989

Evolutionary relationships between laboratory mice and subspecies of Mus musculus based on the restriction fragment length variants of the chymotrypsin gene at the Prt-2 locus.

Restriction endonuclease fragment length variants in mice were compared by Southern blot analysis using the cDNA probe pcXP33 for the chymotrypsin gene. The variants were detected in the restriction patterns generated by fragments from digestions with BglII, EcoRI, HindIII, Pstl, SacI, and XbaI. The set of protein phenotypes and the restriction patterns of chymotrypsin gene were examined in many laboratory strains and wild subspecies. Most laboratory strains (26 strains) are grouped into a set defined as Set 1, but only a few laboratory strains (AU/SsJ and five BALB/c sublines) are classified as belonging to Set 2. Of wild subspecies, only BRV-MPL (M. brevirostris) can be placed in Set 1, while DOM-BLG and SK/Cam (M. domesticus) belong in Set 2. The assignment of an appropriate set defined by the characteristics of the chymotrypsin gene has also been investigated in M. musculus, two Chinese subspecies, M. yamashinai, M. molossinus, and M. castaneus, and the evolutionary relationship between laboratory mice and various subspecies of Mus has been examined.

Animals↗

PubMed1989

Clinico-histochemical studies on type 4 carcinoma of the stomach--with special reference to mucopolysaccharides and sialic acid in tumor tissue.

One hundred and twenty-one patients with gastric cancer of Borrman IV (type 4) were classified into two types according to the macroscopic appearance of their tumors, namely, those tumors with giant folds (type G, n = 84) and those without giant folds (type P, n = 37). A large percentage of the cases in both type groups had advanced stage carcinoma. Type G was found to be predominant in young women and the incidence of high-grade lymph node metastasis was higher in type G than in type P. Histochemically, it was shown that the tumor interstitium of type G contained obviously many more acid mucopolysaccharides (AMPS) than the localized Borrman II (type 2) gastric cancer, which was used as a control. The results of enzymatic digestion tests suggested that the amounts of hyaluronic acid, chondroitin sulfate, and sialic acid were greater in type G than in type P or the localized type, the differences involved being marked between type G and the localized type.

Adenocarcinoma↗

PubMed1989

Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai.

Three murine monoclonal antibodies, OA-1, OA-2 and OA-3, against okadaic acid were prepared from hybridoma clones obtained by fusion of mouse 653 myeloma cells with mouse immune spleen cells sensitized to okadaic acid-ovalbumin conjugate. Each antibody reacted with dinophysistoxin-1 ( = 35-methylokadaic acid) as well as okadaic acid, but did not react with the other diarrhetic shellfish poisons or related compounds, such as 7-O-palmitoyl-okadaic acid (analogue of dinophysistoxin-3), pectenotoxin-1 and yessotoxin. A competitive inhibition enzymelinked immunosorbent assay which employed OA-3 antibody was performed and showed a sensitivity of about 10 ppb (10 ng/ml) for okadaic acid. This simple and time-saving ELISA assay system may be useful for the specific detection of diarrhetic shellfish poisons.

Animals↗

PubMed1989

Arachidonic acid metabolites by cytochrome P-450 dependent monooxygenase pathway in bovine adrenal fasciculata cells.

[1-14C]Arachidonic acid was incubated with microsomes of bovine adrenal fasciculata cells in the presence of 1 mM NADPH for 30 min at 37 degrees C. The metabolites were separated and purified by reverse phase high performance liquid chromatography, and identified by gas chromatography-mass spectrometry. Identified metabolites were four dihydroxyeicosatrienoic acids (DHTs) (5,6-, 8,9-, 11,12-, 14,15-DHTs), 20-hydroxyeicosatetraenoic acid and eicosatetradioic acid. The formation of these metabolites was dependent on NADPH and inhibited by SKF-525A. 14,15-DHT was also formed by isolated bovine adrenal fasciculata cells. These results indicate that cytochrome P-450 dependent arachidonate monooxygenase pathway may exist in bovine adrenal fasciculata cells. Addition of the chemically synthesized epoxyeicosatrienoic acids (EETs) to isolated bovine adrenal fasciculata cells stimulated cortisol production. Among four regioisomeric EETs, 14,15-EET was most potent and stimulated steroidogenesis in a dose-related manner over a range of 0.5 to 5.0 microM.

8,11,14-Eicosatrienoic Acid↗

PubMed1989

The influence of ouabain on twitch contractions in the presence of veratridine.

1. Direct stimulation evoked twitches in mouse diaphragm muscles in presence of 10 microM D-tubocurarine in vitro. Effects of ouabain and their dependence on K+ were examined on the twitch responses and action potentials in the presence and absence of twitch potentiators. 2. Ouabain inhibited twitch contractions only in the presence of veratridine, aconitine and monensin while it had no inhibitory effect on control twitches. The interactions between ouabain and these twitch potentiators depended on the presence of external K+, except in the case of monensin. 3. Removal of Ca2+ from a bathing solution accelerated the potentiating effect of veratridine and the antagonizing effect of ouabain. 4. Caffeine further potentiated the twitches which had been attenuated by ouabain combined with veratridine. 5. Ouabain combined with veratridine consistently decreased resting membrane potentials, action potentials and overshoot potentials and prolonged time to peak of and duration of the muscle action potentials. 6. Tetraethylammonium, 4-aminopyridine, and caffeine produced twitch potentiation which was insensitive to ouabain or the removal of K+. 7. These results suggest that twitch contractions in the presence of activators of sodium channels link with activation of Na+-K+-ATPase. Accumulation of Na+ inside the muscle fibres may uncouple the excitation-contraction system. 8. This uncoupling may not include the caffeine-sensitive process that controls the release of Ca2+ from the sarcoplasmic reticulum. Na+ accumulation may decrease transmembraneous gradient of this ions, thereby causing a reduction in excitation coupled with twitch contraction.

4-Aminopyridine↗