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Biomedical subjects

H Noda

Publications and source records attributed to H Noda.

At least 181 records · Page 10Linked to original sources
PubMed1992

Hemodynamic and endocrine changes associated with hypotensive action of amosulalol in essential hypertension.

To clarify the hemodynamic and endocrine mechanisms of the hypotensive effect of amosulalol, an alpha- and beta-adrenoceptor antagonist, 19 patients with essential hypertension received amosulalol (20-80 mg/day; average 48.4 mg/day) for 16 weeks. Mean blood pressure (MBP) was significantly decreased (105 +/- 1 vs. 120 +/- 1 mm Hg, p less than 0.001), associated with a decrement in heart rate (HR). Although both cardiac index (CI, 3.68 +/- 0.09 vs. 3.91 +/- 0.09 L/min/m2, p less than 0.001) and total peripheral resistance index (TPRI, 2,271 +/- 78 vs. 2,441 +/- 79 dynes.s.cm-5.m2, p less than 0.001) were reduced, changes in TPRI positively correlated with those of MBP (r = 0.9155, p less than 0.001) but the change in CI did not (r = 0.3568, NS). Plasma renin activity (PRA, 0.55 +/- 0.09 vs. 0.95 +/- 0.14 ng/ml/h, p less than 0.05) and aldosterone concentration (4.6 +/- 0.4 vs. 8.6 +/- 0.5 ng/dl, p less than 0.001) were also decreased with amosulalol. Thus, the hypotensive effect of amosulalol may be due mainly to vasodilation by alpha 1-blocking action. In addition, this hypotensive effect may be facilitated by either beta-blocking action such as decreased cardiac output (CO), with suppression of reflex tachycardia or of the renin-angiotensin-aldosterone system.

Adult↗
PubMed1992

Sonomicrometric studies on the effects of long-term pumping of cardiac assist device on the bulk and regional mechanics of the normal left ventricle in goat.

Pneumatically driven, diaphragm type left ventricular assist devices (LVADs) were implanted into 2 goats with normal hearts for approximately 1 month to study the effects of long-term pumping of LVAD on the cardiac mechanics. One sham-operated goat was used to obtain control data. Diameters and myocardial segment lengths of the left ventricle were measured with an ultrasonic displacement meter to calculate the bulk mechanical work (BMW) and regional myocardial mechanical work (RMW), respectively. The LVAD was pumped in the 2:1 drive mode (one counterpulsated pumping in every two cardiac cycles), and was temporarily driven in the 1:1 mode (one pumping in every cardiac cycle) or stopped to obtain the data under these conditions. During the second half of the post-operative period while the animal condition was stable, the BMW in the 2:1 and 1:1 modes were approximately 59% and 72% of that observed under the temporary pump-off condition (0.22 W/(100 g)), respectively. The RMW in the 2:1 and 1:1 modes were 69% and 74% of that obtained during pump-off (6.2 mW/cm3), respectively. The myocyte diameter in the subendocardial layer was reduced by unloading effect of 1-month pumping, whereas those in middle and subepicardial layer showed little change.

Animals↗
PubMed1992

[A new hemodynamic diagram, using COP-PCWP and CI as parameters, after open heart surgery].

In 24 patients subjected to cardio-pulmonary bypass (CPB) operation, changes in colloid oncotic pressure (COP), cardiac index (CI), respiratory index (RI), and pulmonary capillary wedge pressure (PCWP) were measured within a 48 hour period. The patients were divided into two groups according to dose levels of catecholamine. In 18 patients received small catecholamine doses, a stable hemodynamic and respiratory status were maintained. However, 6 patients received catecholamine doses of more than 15 micrograms/kg/min exhibited low COP, low CI, high RI and high PCWP. In this study we designed a new hemodynamic diagram using COP-PCWP and CI as parameters of the cardiac function. We consider that these parameters are more suitable than Forrester's parameters to evaluate the patient's condition before and after open heart surgery.

Adult↗
PubMed1992

Clinical evaluation of right ventricular function in patients with left ventricular assist device (LVAD).

Right ventricular function (RVF) during LVAD support can be a threat for patient survival. Despite extensive research, RVF and its interference with left heart function is unclear. This study examines RVF in a retrospective analysis of 14 patients. Hemodynamic data were collected, including heart rate (HR), central venous pressure (CVP), mean pulmonary artery pressure (mPAP), total cardiac output (CO), calculated stroke volume index (SVI) and right ventricular stroke work index (RVSWI). In all patients, CO increased gradually throughout the study period; CVP showed no significant decrease; mPAP and PCWP decreased significantly over the time period; SVI improved and RVSWI increased from the starting level prior to implantation of the LVAD. We conclude that the CO improved with a lowering of the right ventricular afterload combined with a decrease in total circulating volume. The improvement of RVF with LV assist makes this device an option as a bridge to transplant.

Blood Pressure↗
PubMed1991

High-performance liquid chromatographic method for direct separation of 5-(p-hydroxyphenyl)-5-phenylhydantoin enantiomers using a chiral tris(4-methylbenzoate) column.

After simple purification of the incubation mixture of phenytoin in isolated rat hepatocytes, 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH), which formed as a major metabolite, was readily resolved to each enantiomer by direct high-performance liquid chromatography on a cellulose tris(4-methylbenzoate) column, with a mobile phase of ethanol-water. It was also observed that the formation of S-(-)-p-HPPH was dominant, and the S/R ratio was 11.5.

Animals↗
PubMed1991

Evaluation of a new calcium containing cardioplegic solution in the isolated rabbit heart in comparison to a calcium-free, low sodium solution.

Isolated perfused rabbit hearts were studied to compare the effects of 3 hour ischemic arrest following either calcium-free or calcium-containing cardioplegia, on the recovery of isovolumic function of the left ventricle, coronary flow, release of creatine phosphokinase and myocardial water content. The hearts perfused with the calcium-containing solution (Ca 0.5 mmol/L) showed better recovery of the developed pressure in the left ventricle, and its first derivative and compliance. Coronary flow at a constant perfusion pressure was better restored during reperfusion in the hearts with calcium-containing solution. The release of less CPK and a lower water content were also observed in the hearts reperfused with calcium-containing solution. We concluded that calcium-containing cardioplegic solution with a high concentration of magnesium (10 mmol/L) was superior to calcium-free solution for myocardial protection.

Animals↗
PubMed1991

Effects of dihydroheptaprenol on the neutrophil function of postpartum dairy cows.

Neutrophil responses were evaluated in dairy cows at parturition and on 1, 2, 3, 5 and 7 days after they were given dihydroheptaprenol (DHP) (0.5 mg/kg body weight) at parturition. The chemiluminescent index increased significantly (P less than 0.05) from parturition to 1 day after parturition in cows injected with DHP. No significant differences were observed in the number of neutrophils between untreated and DHP-treated groups of dairy cows during the immediate postparturient period.

Animals↗
PubMed1991

Converging eye movements evoked by microstimulation of the fastigial nucleus of macaque monkeys.

Stimulation of the dorsal part of the fastigial nucleus in macaques is known to evoke ipsilateral saccades, while those of the ventral part produce contralateral saccades. It was found that stimulation of the transitional zone moved the visual axis (eyes) to converge at an area (focus) in the oculomotor range, regardless of the initial eye position. These saccades were designated as 'converging saccades'. Converging saccades were directed to the focus, but the eyes did not attain the focus in one motion. Only the repetition of stimuli brought the eyes near the focus. When stimulation is applied to the transitional zone at progressively more ventral sites, the focus gradually shifted, starting from the ipsilateral hemifield to the contralateral hemifield by taking various routes.

Animals↗
PubMed1991

Pathways and terminations of axons arising in the fastigial oculomotor region of macaque monkeys.

The majority of axons from the fastigial oculomotor region (FOR) decussated in the cerebellum at all rostrocaudal levels of the fastigial nucleus (FN) and entered the brainstem via the contralateral uncinate fasciculus (UF). Some decussated axons separated from the UF and ran medial to the contralateral superior cerebellar peduncle and ascended to the midbrain. Uncrossed FOR axons advanced rostrolaterally in the ipsilateral FN and entered the brainstem via the juxtarestiform body. The decussated fibers terminated in the brainstem nuclei that are implicated in the control of saccadic eye movements. In the midbrain, labeled terminals were found in the rostral interstitial nucleus of the medial longitudinal fasciculus, a medial part of Forel's H-field, the periaqueductal gray, the posterior commissure nucleus, and the superior colliculus of the contralateral side. In the pons and medulla, FOR fibers terminated in a caudal part of the pontine raphe, the paramedian pontine reticular formation, the nucleus reticularis tegmenti pontis, the dorsomedial pontine nucleus of the contralateral side, and the dorsomedial medullary reticular formation of both sides. In contrast, FOR projections to the vestibular complex were bilateral and were mainly to the ventral portions of the lateral and inferior vestibular nuclei. No labeled terminals were found in the following brainstem nuclei which are considered to be involved in oculomotor function: oculomotor and trochlear nuclei, interstitial nucleus of Cajal, medial and superior vestibular nuclei, periphypoglossal nuclei, and dorsolateral pontine nucleus. Labeling appeared in the red nucleus only when HRP encroached upon the posterior interposed nucleus.

Animals↗
PubMed1991

Effects of fastigial stimulation upon visually-directed saccades in macaque monkeys.

When the initial eye position was changed by stimulating the fastigial nucleus prior to visually-directed saccades, monkeys could not compensate for the stimulation-induced movement. The line of sight missed the target location by a distance and direction almost equal to the vector of the evoked saccade. When the stimulation was delivered 75-130 ms after the target presentation, saccades were triggered prematurely. Their initial movement reflected only the evoked saccade in some response and reflected the vector sum of the evoked and visually-directed saccades in the other. In contrast, when stimulus latencies were greater than 130 ms. saccades started toward the target location. The visuomotor processing for saccades seemed to be completed during this period, which is approximately half the latency of normal saccades. When the stimulation was applied while the eyes were already in motion, the trajectories of the saccades were strongly modified and terminated in deviated locations. These results indicate that cerebellar output impulses are projected downstream to saccade-programming circuits where visual information has already been converted into motor-command signals.

Animals↗
PubMed1991

Divergent axon collaterals from fastigial oculomotor region to mesodiencephalic junction and paramedian pontine reticular formation in macaques.

Collateralization of efferent fibers from the fastigial oculomotor region (FOR) to the paramedian pontine reticular formation (PPRF) and the mesodiencephalic junction (MDJ) was studied in macaque monkeys using a fluorescent double-labeling technique. Retrogradely-labeled neurons in the contralateral FOR were examined following injections of fast blue (FB) into the MDJ and diamidino yellow (DY) into the PPRF, or vice versa. Some FOR neurons were labeled with FB, while some other FOR neurons were labeled with DY and intermingled within the FOR. While single-labeled cells in the FOR projected either to the PPRF or to the MDJ, the presence of double-labeled cells indicated that the FOR contains neurons whose axons collateralize to project to both the MDJ and PPRF. These are regarded as the preoculomotor nuclei responsible for vertical and horizontal saccades, respectively.

Animals↗
PubMed1991

The effect of microstimulation of the oculomotor vermis on discharges of fastigial neurons and visually-directed saccades in macaques.

The present study confirmed our previous reports that neurons in the fastigial oculomotor region (FOR) of the macaque show presaccadic bursts during contralateral saccades and that the burst duration is closely related to the duration of the accompanying saccade. Furthermore, when the burst duration was reduced by subthreshold electrical stimulation applied to the oculomotor vermis prior to the onset of the burst, the impending visually-directed saccade became hypometric. The reduction in the burst duration was closely related to the degree of the hypometria. Since saccadic burst neurons in the FOR constitute the sole output channel for saccadic signals of the oculomotor vermis, the findings support the hypothesis that the cerebellum can regulate the amplitude of eye movements.

Animals↗
PubMed1991

Brainstem mossy fiber projections to lobules VIa, VIb,c, VII and VIII of the cerebellar vermis in the rat.

The brainstem mossy-fiber projections to lobules VIa, VIb,c, VII and VIII of the cerebellar vermis were studied by retrograde transport of horseradish peroxidase in the rat. The distribution of labeled cells indicated that these lobules received major projections from topographically different locations of the basilar pontine nuclei and the nucleus reticularis tegmenti pontis. Lobules VIa and VIII received an additional strong projection from the lateral reticular nucleus. Moderate projections were found to reach lobule VIa from the raphe pontis and external cuneate nucleus; lobules VIb,c from the raphe pontis, lateral reticular nucleus, and a group of cells in the lateral tegmentum; lobule VII from the spinal vestibular nucleus and a lateral tegmental cell group; and lobule VIII from the medial and spinal vestibular nuclei, nucleus intercalatus and Roller of the perihypoglossal nuclei, and the main cuneate nucleus. The quantitative and topographical differences in the origin of mossy fibers suggest that these lobules may subserve slightly different functions.

Afferent Pathways↗
PubMed1991

A reovirus in the brown planthopper, Nilaparvata lugens.

A new virus, belonging to the reovirus group, was found in an apparently healthy colony of the brown planthopper, Nilaparvata lugens, and was referred to as the Nilaparvata lugens reovirus (NLRV). The virus was found in the cytoplasm of the insect cells, sometimes associated with tubular structures, which is one of the characteristic features in tissues infected with reoviruses. The virus was purified by carbon tetrachloride clarification, polyethylene glycol precipitation, differential and CsCl equilibrium centrifugations. The virus has double-shelled particles approximately 65 nm in diameter, containing 10 genome segments of dsRNA. The electrophoretic profile of the dsRNA segments differed from those of viruses associated with rice planthoppers and leafhoppers. Seven proteins were detected in a purified preparation of the virus: four were associated with the core particle and three with the outer shell. A virus antigen was detected in individual insects by ELISA. The virus is retained after injection and is vertically transmitted to the offspring.

Animals↗
PubMed1991

Nucleotide sequences of genome segments S8, encoding a capsid protein, and S10, encoding a 36K protein, of rice gall dwarf virus.

The nucleotide sequences of DNAs complementary to the eighth (S8) and the tenth (S10) largest of the 12 genome segments of rice gall dwarf virus (RGDV) were determined. The S8 and S10 segments consist of 1578 and 1198 nucleotides, each with a single open reading frame extending for 1278 nucleotides from nucleotide 21, and 960 nucleotides from nucleotide 22, respectively. S8 encodes a polypeptide of 426 amino acids with an Mr of 47419. The amino acid sequences of several peptide fragments of the major outer capsid protein reported as 45K were contained in the predicted polypeptide. This protein, renamed the 47K protein, showed high homology with the outer capsid proteins of rice dwarf virus (RDV) and wound tumour virus (WTV); there was 56, 52 and 48% amino acid sequence identity between RGDV and WTV, RGDV and RDV, and RDV and WTV, respectively. S10 had the coding potential for a polypeptide of 320 amino acids with an Mr of 36,095 (36K protein), which exhibits 32% and 35% amino acid sequence identity with the predicted translation product of RDV S9 and the P9 capsid protein encoded by WTV S11, respectively. The conserved terminal sequences 5' GG...GAU 3' which are present in all genome segments of WTV and RDV so far analysed, and in S9 of RGDV, were also found in RGDV S8 and S10. This conserved sequence together with the segment-specific inverted repeats found in the terminal sequence of RGDV S8 and S10 are thus characteristic structures common to all three phytoreoviruses. The nucleotide sequence of the region surrounding the inverted repeats was more similar between RGDV and WTV than between RGDV and RDV.

Amino Acid Sequence↗
PubMed1991

Postnatal changes in lymphocyte function of dairy calves.

Lymphocyte blastogenic response, B-lymphocyte population and antibody-producing activity of lymphocytes were determined to evaluate the lymphocyte function in neonatal calves during the first 4 weeks of life. The mean percentage of B-lymphocytes ranged from 10.2 to 12.5% during the first 14 days of life and from 15.3 to 17.5% in calves from the day 21 to day 28 after birth. The absolute number of B-lymphocytes increased significantly (P less than 0.05) from 370/microliters at birth to 736/microliters on day 28 after birth. The mean stimulation index of blastogenic response, measured by fluorometric assay, ranged from 5.75 to 6.61 with Con A, from 5.29 to 5.98 with PHA and from 1.89 to 2.50 with PWM. The mean (+/- S.D.) number of plaque forming cells ranged from 22.0 (+/- 12.0) to 24.7 (+/- 9.2) in cultured lymphocytes from 5 calves at birth to 14 days after birth and their levels increased markedly from 137.8 (+/- 88.3) to 162.0 (+/- 57.8) in lymphocytes from 20 days to 28 days after birth. The present study showed that antibody-producing activity of lymphocytes is lower in calves within 3 weeks after birth compared to that of calves 3 weeks after birth, indicating that neonatal calf lymphocytes have a low antibody-producing activity at least up to 1 month after birth.

Animals↗
PubMed1991

Long-term respiratory assistance using a right ventricular assist device system and a membrane oxygenator.

A new method for long-term respiratory assistance using a right ventricular assist device (RVAD) system and a membrane oxygenator (MO) was designed and evaluated. An air-driven RVAD was implanted between the right atrium and the pulmonary artery in five goats and an MO was set on the outlet conduit of the RVAD 2 weeks postoperatively. Two types of MOs [the SciMed (Life Systems) silicone sheet MO and a prototype MO using a novel multilayered composite membrane] were used in this study. Respiratory support with this system under systemic heparinization could be conducted for 4-8 days without major problems accompanied with conventional extracorporeal membrane oxygenation (ECMO) such as surgical bleeding, destruction of the blood components, serum leakage, insufficient bypass flow, and fatal systemic thrombosis. This method opened the possibility for ECMO to be used as a bridge before lung or heart-lung transplantation.

Animals↗