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Biomedical subjects

M Nishimura

Publications and source records attributed to M Nishimura.

At least 1,189 records · Page 66Linked to original sources
PubMed1987

[Therapeutic effects of a combination of intermediate-dose cytosine arabinoside, adriamycin and vincristine in relapsed acute leukemia].

Eleven cases of acute leukemia, 8 relapsed and 3 refractory to a conventional induction chemotherapy, were treated with a combination of intermediate-dose cytosine arabinoside (ara-C), adriamycin (ADM) and vincristine (VCR). They consisted of 9 ANLL and 2 ALL. The therapeutic regimen consisted of 1-hour infusion of ara-C of a dose of 500 mg/m2 every 12 hours for 6 days from days 3 to 8, ADM, 40 mg/m2, on day 1 and VCR, 1.4 mg/m2, on day 2. Among 11 cases in which an evaluation was possible, 7 obtained complete remission (CR). The CR rate was 77.8% in the 9 cases of ANLL. The toxicity of this regimen included the following: conjunctivitis in 4 of 11 cases (36%), nausea and vomiting in 9 of 11 cases (91%) and hair loss in all cases, although no toxicities of the central nervous system of liver were observed. The mean level of serum concentration of ara-C was above 10 microM at 15, 30 and 60 minutes after the initiation of infusion. The therapeutic effect of this regimen consisting of intermediate-dose ara-C is expected to be useful not only in induction of refractory and relapsed acute leukemia, but also in the postremission therapy of CR cases.

Acute Disease↗
PubMed1986

Topographic representation of lower and upper teeth within the trigeminal sensory nuclei of adult cat as demonstrated by the transganglionic transport of horseradish peroxidase.

Transganglionic transport of horseradish peroxidase-wheat germ agglutinin conjugate (HRP-WGA) entrapped in hypoallergenic polyacrylamide gel was used to study the patterns of termination of primary afferents that innervate the lower and upper tooth pulps within the trigeminal sensory nuclear complex (TSNC). HRP injections were made into the inferior and superior alveolar nerves in order to compare the central projections of the whole nerve with those from tooth pulps. In addition, the relationship between the distribution of the trigeminothalamic tract cells and the projection sites of the tooth pulp afferents was investigated by injecting HRP into the posterior ventral thalamus. HRP-labeled tooth pulp afferent fibers innervating the lower and upper teeth projected to the subnucleus dorsalis (Vpd) of pars principalis, the rostrodorsomedial part (Vo.r) and nucleus dorsomedialis (Vo.dm) of pars oralis, the medial regions of pars interpolaris, and laminae I, II, and V of pars caudalis. Terminal fields of the lower tooth pulp afferents formed a rostrocaudally running, uninterrupted column from the midlevel of Vpd to the caudal tip of caudalis. In contrast, the column of termination of upper tooth pulp afferents was discontinuous at the Vpd/Vo.r transition, and ended at the more rostral level of the caudalis than that of the lower tooth pulp afferents. The representation of the lower and upper teeth in the TSNC was organized in a somatotopic fashion which varied from one subdivision to the next, although terminal zones of the inferior and superior alveolar nerves overlapped within the Vo.r, Vo.dm, and dorsomedial part of rostral pars interpolaris. The lower and upper teeth were represented in the Vpd, Vo.r, Vo.dm, medial region of pars interpolaris, and laminae I, II, and V, in a ventrodorsal or caudorostral, dorsoventral, lateromedial, dorsoventral, and mediolateral or dorsomedial-ventrolateral sequence, respectively. The smaller, more focal terminal areas of the teeth contrasted sharply with more extensive terminal fields of the alveolar nerves. The HRP injections within the thalamus indicated that neurons in Vpd, the caudal pars interpolaris, and laminae I/V of caudalis, which are subdivisions of TSNC that receive pulpal projections, sent their axons to the ipsilateral and contralateral posterior ventral thalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

Alveolar Process↗
PubMed1986

Purification and characterization of heme-containing low-activity form of catalase from greening pumpkin cotyledons.

In germinating pumpkin seeds, catalase is synthesized as a precursor (59-kDa) form, with molecular mass larger than the mature molecule (55 kDa). Both the precursor and mature forms of catalase are localized in the microbodies, i.e., glyoxysomes and leaf peroxisomes [Proc. Natl. Acad. Sci. USA 81, 4809-4813 (1984)]. We have now purified the 59-kDa catalase precursor and compared its properties with those of the 55-kDa mature molecule. The molar catalytic activity of the 59-kDa catalase was tenfold lower than that of the 55-kDa molecule, whereas the heme content was found to be same, with both forms containing four hematin groups per molecule. It is inferred from these results that the low activity of the 59-kDa molecule is not related to the binding of heme to the protein, but presumably involves conformational differences between the 59-kDa and 55-kDa molecules. We have further found that the reduction of total catalase activity in pumpkin cotyledons during greening was due to a decrease in the amount of the enzymically active 55-kDa catalase accompanying an increase in the 59-kDa molecule.

Catalase↗
PubMed1986

Optimal mode of transesophageal atrial pacing.

The optimal mode of transesophageal atrial pacing was determined by clinical electrophysiologic studies in 15 healthy adult volunteers. The point at which the unipolar atrial electrogram was biphasic and largest in amplitude (35.4 +/- 1.6 cm from the incisors) was considered the best stimulation site for atrial pacing. The stimulation threshold on bipolar pacing (using the proximal pole as cathode and the distal pole as anode) at this site was 27 +/- 7 mA, which was significantly lower (p less than 0.001, n = 10) than that on unipolar cathodal stimulation (41 +/- 8 mA). Although the stimulation threshold tended to be higher with a No. 10Fr electrode catheter (30 +/- 5 mA) than with a No. 6Fr catheter (27 +/- 7 mA), the difference was statistically insignificant (n = 9). When the interpolar distance in bipolar stimulation was varied in 5 steps from 12 to 80 mm, the threshold was lowest at the distance of 24 mm. Of the 10 pulse durations tested, ranging from 0.25 to 128 ms, 8 ms appeared most desirable in minimizing the total amount of current and chest discomfort accompanying the pacing. With the optimal site, interpolar distance and pulse duration, transesophageal atrial pacing was successfully performed in all patients, without producing significant complications such as chest pain. Transesophageal atrial pacing is noninvasive, technically simple and efficient, and may be valuable in the diagnosis and treatment of various cardiac arrhythmias.

Adult↗
PubMed1986

[A study of utilization review in hospitals--focusing on medical statistics].

It is a matter of course that health care is an important issue closely related to the daily life of residents. In this situation, university hospitals, although their main aim is research and education, also play a significant role as core hospitals in various regions of the community. By reviewing hospital utilization, extended to facilities in a given area, we first analyzed the medical service area and the length of stay in the hospital affiliated to the University of Occupational and Environmental Health, on the basis of discharge various directions of facility planning based on future bed using control, including addition of beds, and also attempted to evaluate the actual state of annual facility management with the aid of computer.

Catchment Area, Health↗
PubMed1986

Nature of leukemic stem cells in murine myelogenous leukemia.

We investigated the nature of myelogenous leukemic stem cells in mice. L-8057, a megakaryoblastic leukemia cell line used in this study, produces in vivo and in vitro colonies. By means of typical chromosomal aberrations in L-8057, one can conveniently detect the origin of the cells in each colony derived from a leukemic stem cell. Direct evidence of whether cells from each colony had leukemogenicity in recipient mice was successfully obtained by the colony transplantation assay. Both leukemic colony-forming unit-spleen (L-CFU-s) and leukemic colony-forming unit-culture (L-CFU-c) in L-8057 may have belonged to the same differentiating stage in the stem cells because of their similar radiosensitivity, although some parts of the L-CFU of L-8057 seemed to have lost their capability to regenerate L-CFU-s when the cells were plated in dishes. This leukemic stem cell preserves high self-renewal ability in vitro after 10 passages. In addition, in vitro colony formation by this leukemic cell during the above course of serial passages did not require any additional exogenous stimulators. The same sort of trials have been made on other types of leukemias. Leukemic stem cells showed remarkable variety in their response to stimulating factors and in their self-renewal activity, which suggests that they may have consisted of heterogeneous populations.

Animals↗
PubMed1986

Focal vulnerability of developing brain: CT studies on disproportionally dilated lateral ventricles.

Cranial computed tomography (CT) of 108 cases with dilated lateral ventricles was reviewed to elucidate the relationship between focal vulnerability of developing brain and disproportional dilatation of lateral ventricles. CT findings of 108 cases with symmetrical dilatation of lateral ventricles were classified into three types by morphometry of lateral ventricles: anterior horn predominant type (31 cases), diffuse type (36 cases), posterior horn predominant type (41 cases). Posterior horn predominant type has a tendency to occur in congenital anomalies and premature brain damage, and anterior horn predominant type in infantile brain damage. This disproportional dilatation of anterior or posterior horns suggests a vulnerability of periventricular structure in developing brain.

Adolescent↗
PubMed1986

Preventive effects of cyclosporin on diabetes in NOD mice.

Non-obese diabetic mice aged 30 to 60 days were treated orally with Cyclosporin at doses of 25, 15 and 2.5 mg/kg every 2 days until 160 days of age. Diabetes developed in 12 out of 18 oil-treated mice (67%), with partial to complete Langerhans' islet destruction associated with lymphocytic infiltration. The non-obese diabetic mice showed a plasma glucose concentration of 6.62 +/- 0.92 mmol/l (mean +/- SD) at 50 days of age. The plasma glucose level of oil-treated non-obese diabetic mice gradually increased after 130 days of age and reached 14.0 to 19.0 mmol/l at 160 days of age, while Cyclosporin-treated non-obese diabetic mice showed neither clear increase of plasma glucose levels nor development of insulitis. The cumulative incidence of diabetes in Cyclosporin-treated mice was significantly lower than that in oil-treated mice (p less than 0.01). Subsequently, Cyclosporin treatment was started after development of glucose intolerance. Twenty-five mg/kg of Cyclosporin was administered every 2 days for 35 days. Cyclosporin appeared to have little therapeutic effect on diabetes in non-obese diabetic mice.

Animals↗
PubMed1986

Effects of sulfhydryl agents on neuromuscular transmission in the presence or absence of cadmium.

To test whether thiol groups are involved in neuromuscular transmission and its blockade by cadmium, the influence of sulfhydryl reagents were investigated on neuromuscular transmission, in the presence or absence of cadmium, using isolated mouse phrenic nerve-diaphragm muscles. Cadmium attenuated twitches evoked by indirect shocks but had almost no effect on twitches by direct shocks in the presence of d-tubocurarine (2.5 microM). The inhibitory effect was reversed by cysteine or by an increase in external calcium. The sulfhydryl oxidizing agent DTNB 5,5'-dithiobis(2-nitrobenzoic acid) potentiated the inhibitory effect of cadmium. Conversely, the reducing agent dithiothreitol (DTT) inhibited this effect. The potentiation by DTNB could be reversed by subsequent application of DTT. The sulfhydryl reagents had no influence on neuromuscular transmission in the absence of cadmium. Neuromuscular transmission was inhibited by the removal of calcium. This inhibition could be reversed by readmission of calcium. This restoration was neither potentiated nor reduced in the presence of these sulfhydryl reagents: It is suggested that an interaction of cadmium with thiol groups is independent of its calcium antagonistic action on neuromuscular transmission. Thiol groups may protect the transmission from the effect of cadmium.

Animals↗
PubMed1986

A family with myotonic dystrophy associated with diffuse cardiac conduction disturbances as demonstrated by His bundle electrocardiography.

In a family with myotonic dystrophy, three siblings showing ECG abnormalities were subjected to His bundle ECG studies. The duration of the disease ranged from 9 to 24 years. All three siblings had prolonged HV intervals (His-Purkinje conduction times) of 70 to 80 msec. The sister with the shortest duration of the disease had second-degree atrioventricular (AV) nodal block as well as left posterior fascicular block, the younger brother had left anterior fascicular block, and the elder brother with the longest history had first-degree AV block without bundle branch or fascicular block. With regard to associated arrhythmias, however, the elder brother developed paroxysmal ventricular tachycardia, apparently due to reentry involving the right bundle branch system, whereas the younger brother and sister had sinus bradycardia alone. This study reveals the prevalence of diffuse conduction disturbances of the specialized conducting system in a family with myotonic dystrophy.

Adult↗
PubMed1986

Characterization by EPR spectroscopy of cytochrome b-562 isolated from the cytochrome b-c1 complex of Rhodopseudomonas sphaeroides R-26.

The EPR spectra of cytochrome b-562 isolated from the cytochrome b-c1 complex of Rhodopseudomonas sphaeroides were measured at liquid helium temperature. The purified cytochrome b-562 gives a high spin signal at g = 6.0. Anaerobic titration of this signal confirmed the presence of two redox components with Em = 40 and -110 mV at pH 7.5. These values are consistent with the published ones, Em = 55 and -100 mV at pH 7.0, that were optically estimated for the same type of preparation (Iba et al. (1985) FEBS Lett. 183, 151-154). The power saturation behavior of the g = 6.0 signal at different redox potentials indicated a direct spin-spin interaction between these two redox centers.

Cytochrome b Group↗
PubMed1986

Immunocytochemical Analysis Shows that Glyoxysomes Are Directly Transformed to Leaf Peroxisomes during Greening of Pumpkin Cotyledons.

The functional transition of glyoxysomes to leaf peroxisomes occurs during greening of germinating pumpkin cotyledons (Cucurbita sp. Amakuri Nankin). The immunocytochemical protein A-gold method was employed in the analysis of the transition using glyoxysomal specific citrate synthase immunoglobulin G and leaf peroxisomal specific glycolate oxidase immunoglobulin G. The labeling density of citrate synthase was decreased in the microbodies during the greening, whereas that of glycolate oxidase was dramatically increased. Double labeling experiments using different sizes of protein A-gold particles show that both the glyoxysomal and the leaf peroxisomal enzymes coexist in the microbody of the transitional stage indicating that glyoxysomes are directly transformed to leaf peroxisomes during greening.

Journal Article↗
PubMed1986

Factors influencing an increase in spontaneous transmitter release by hypoxia at the mouse neuromuscular junction.

To test a possibility that the functional buffering of intracellular Ca2+ plays a primary role in the enhancement of spontaneous transmitter release during hypoxia, the frequency of miniature end-plate potentials (m.e.p.p.s) was examined under several conditions. At 36 degrees C, hypoxia (bubbling with 95% N2 and 5% CO2) increased the average frequency of m.e.p.p.s from about 3 s-1 to 100 s-1 or more, in a standard Krebs-Ringer solution. This effect declined with a decrease in the temperature and was much reduced at 24 degrees C. Removal of external Ca2+ (addition of 2 mM-EGTA), increase of Mg2+ levels to 5 mM, and treatment with 20 microM-ouabain, which gave a slight increase, did not reduce the rise in m.e.p.p. frequency during hypoxia. Pre-incubation of the tissue in a solution containing 10 mM-KCl at 24-32 degrees C and its subsequent exposure to hypoxia caused a very marked increase in m.e.p.p. frequency, while incubation in 10 mM-KCl alone caused a small rise in the frequency. These data indicate that this combination potentiates the individual effects of each treatment. These experiments suggest that the hypoxia-induced increase in spontaneous transmitter release is primarily due to an increase in intracellular Ca2+ levels, probably because of inhibition of mechanisms which control buffering and extrusion of intracellular Ca2+. The release and influx mechanisms which elevate intraterminal Ca2+ may also be involved passively in the effect of hypoxia.

Action Potentials↗
PubMed1986

Photophosphorylation and oxidative phosphorylation in intact cells and chromatophores of an aerobic photosynthetic bacterium, Erythrobacter sp. strain OCh114.

Light-induced ATP synthesis was studied in intact cells and chromatophores of Erythrobacter sp. strain OCh114. ATP synthesis was measured by both the pH method and the luciferin-luciferase luminescence method. The rate of ATP synthesis was moderate (a typical value of 0.65 mol of ATP per mol of bacteriochlorophyll per min), and synthesis was inhibited by antimycin A. ATP was synthesized under illumination only under aerobic conditions and not under anaerobic conditions. This characteristic was similar to that of other light-induced energy transduction processes in this bacterial species, such as oxidation of reaction center, oxidation of cytochrome c551, and translocation of H+, which were not observed under anaerobic conditions. This phenomenon was reconciled with the fact that the Erythrobacter sp. could not grow anaerobically even in the light. The characteristics of oxidative phosphorylation and ATP hydrolysis were also investigated. The respiratory ratio of chromatophores was 2.3. Typical rates of oxidative phosphorylation by NADH and by succinate were 2.9 mol of ATP per mol of bacteriochlorophyll per min (P/O = 0.22) and 1.1 mol of ATP per mol of bacteriochlorophyll per min (P/O = 0.19), respectively. A typical rate of ATP hydrolysis was 0.25 mol of ATP per mol of bacteriochlorophyll per min in chromatophores. ATPase and adenylate kinase are also involved in the metabolism of adenine nucleotides in this bacterium.

Adenosine Triphosphate↗
PubMed1986

Trachea and lung dimensions in nonsmoking twins: morphological and functional studies.

To compare genetic and environmental factors that determine lung function and dimensions, chest radiographs and pulmonary function were measured in 17 pairs of nonsmoking twin adolescent boys (12 monozygotic pairs and 5 dizygotic pairs). Genetic factors dominated in tracheal width and lung dimensions (height, width, and apicofissural and fissurodiaphragmatic distances) at residual volume. Genetic factors also affected forced vital capacity, functional residual capacity, forced expiratory volume in 1 s, maximum expiratory flow at 25% vital capacity, and maximum flow at 50% vital capacity-to-forced vital capacity ratio. Peak expiratory flow correlated with tracheal width at residual volume. Age correlated with lung dimensions (width and depth) but not with tracheal width. These results indicate that genetic factors determine the dimensions and function of central airways, peripheral airways, and lung parenchyma in adolescent males. The effects of genetic factors on some functional measurements (airway resistance, closing volume-to-vital capacity ratio, and phase III in single-breath N2 washout) may be masked because of poor reproducibility of the tests.

Adolescent↗
PubMed1986

Sympathetic nerve activity, plasma renin activity and water-sodium balance in obese patients with essential hypertension.

Studies were conducted to evaluate the role of water-sodium metabolism on the hypertensive mechanisms in obese patients with essential hypertension (EHT). The obesity index correlated positively with the mean arterial pressure, plasma volume, extracellular fluid volume or total exchangeable sodium, and negatively with plasma noradrenaline concentration or plasma renin activity in EHT. Hypotensive effects of sodium restriction (Na 35 mEq, K 75 mEq) or the natriuretic response to infused dopamine (3 micrograms/kg/min) was remarkable in obese EHT. Fractional excretion of sodium (FENa), which reflects the renal tubular reabsorption of sodium, was significantly lower in obese EHT than that in non-obese or mildly obese EHT. Urinary excretion of free dopamine (UDA) had a positive relationship with simultaneously measured urinary excretion of sodium or FENa. In addition, UDA correlated positively with the obesity index in patients whose weight was under 115% of the ideal weight. On the contrary, the relation between the two parameters was significantly negative in patients whose weight was over 115% of the ideal weight. These findings suggest that the expansion of body fluid volume and sodium, which might result from the blunted natriuretic ability, at least in part, due to an attenuation of the renal dopaminergic activity, play an important role of the hypertensive mechanisms in obese EHT.

Adult↗