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Biomedical subjects

Y Uchida

Publications and source records attributed to Y Uchida.

At least 541 records · Page 30Linked to original sources
PubMed1989

Unaffected electrogenic Na-K pump activity in "diseased" human atrial fibers, as assessed by intracellular K+ activity.

To investigate the role of the electrogenic Na-K pump in the resting membrane of "diseased" or "depolarized" human atrial muscles, intracellular K+ activity (aiK) and resting membrane potential (Vm) were simultaneously measured using double-barreled K(+)-selective microelectrodes. Under perfusion with normal Tyrode's solution (37 degrees C) containing 5.4 mM [K]o, Vm averaged -43.9 +/- 1.4 mV, and aiK was 99.7 +/- 1.3 mM (mean +/- S.E., n = 33). The aiK was comparable to that of atrial muscles obtained from other intact mammalian species. In 5.4 mM [K]o, dihydro-ouabain (DHO) at concentrations of 10(-6) and 10(-5) M significantly decreased aiK and depolarized Vm. Similar decreases in aiK were observed when [K]o was decreased from 5.4 to 0.5 mM or when the temperature of the perfusing solution was decreased from 37 to 22 degrees C. Upon returning [K]o from 0.5 to 5.4 mM at 37 degrees C, aiK increased, Vm hyperpolarized markedly for about 3 min, and this was followed by less marked levels of hyperpolarization in the steady state. The high [K]o-induced increases in aiK were inhibited in the presence of DHO, and at low temperature (22 degrees C). Isoproterenol (10(-7) M) increased aiK and hyperpolarized Vm. Acetylcholine (10(-5) M) hyperpolarized Vm with no change in aiK. The rate of reduction of Na(+)-efflux during application of DHO (10(-5) M) was calculated based on the change in aiK and surface-to-volume ratio of the cell measured electronmicroscopically in the same tissue, and estimated to be 2.6 to 3.8 pmol/(cm2.s), close to the value reported for Purkinje fibers excised from intact animals. We conclude that the Na-K pump functions normally even in "diseased" human atrial muscles, thereby keeping aiK within a physiological range.

Adolescent↗
PubMed1989

[Radial flap: a valuable fasciocutaneous flap for intra-oral reconstruction].

The radial forearm flap, or the forearm flap, is called "Chinese flap" for its development of the chinese doctors, and is originally designed for the correction to the post-burn contraction of the face and neck. The radial forearm flap is one of the fasciocutaneous flap, supplied by the radial artery, and transferred as a single-stage reconstruction micro-surgically. In oral and maxillofacial region, the deltopectral flap (D-P flap) and the pectralis major myocutaneous flap (P-M-M-C flap) are mainly used for the reconstruction. These flaps, however, are sometimes too bulky and limited to transfer, and more require two-stage operations. On the other hand, as the forearm flap being thin and pliable, some doctors use this flap micro-surgically at single-stage free flap reconstruction. Before two years, we have begun to transfer the radial forearm flap for the intra-oral reconstruction. The operation method is as follows. Design and Elevation of the Radial Forearm Flap 1. Using the ultrasonic doppler flow meter, the radial artery and the subcutaneous forearm veins are marked on the skin. 2. The flap is designed 20% larger according to the pattern to be reconstructed, with the distal section of the radial artery as an axis on the forearm and the median vein of forearm inclusively. 3. Before the operation, Allen test must be performed in order to determine whether the hand will survive without a radial arterial in-put. 4. The operation is performed with a arm tourniquet. The margin of the flap are incised down to the deep fascia, isolating and preserving the proximal subcutaneous veins as required.(ABSTRACT TRUNCATED AT 250 WORDS)

Forearm↗
PubMed1989

[Use of the pedicled omentum in chest surgery].

The pedicled omentum finds use in chest surgery for management of complicated problems and prevention of serious complications. Nine patients have been treated with the pedicled omentum. In four patients the goal was preventive, to avoid anastomotic leakage or infection, or to provide a source of neovascularity. In five patients the pedicled omentum was used to obtain healing in the presence of infection. Bronchial fistula, esophageal fistula with pyothorax or mediastinal infections treated successfully. This series demonstrates the efficacy of the pedicled omentum in management of chest problems.

Adult↗
PubMed1989

[A clinical study of pulmonary tissue uptake of cefuzonam and its use in prophylaxis of postoperative infections].

From our study on cefuzonam (CZON), a new antibiotic agent, with regard to pulmonary tissue uptake and use in prophylaxis of postoperative infections in 20 patients undergoing thoracotomy, we were able to reach the following conclusions: 1. Following intravenous infusion over 1 hour of 1 g of CZON immediate preoperatively, the mean serum concentration at 1 hour after commencement of the infusion reached at 41.5 micrograms/ml (serum peak value), then gradually decreased with a half-life in the beta-phase of 1.20 hours. 2. The mean CZON concentration in normal pulmonary tissue at 1 hour after commencement of the infusion was 12.7 micrograms/g with a half-life in the beta-phase of 1.28 hours. Although the number of cases examined was small at only 4, the mean pulmonary tissue level in obstructive pneumonitic lesions was 13.7 micrograms/g, and an average half-life in the beta-phase was 1.65 hours. 3. Mean bronchiolar CZON concentrations at 2, 4, and 6 hours after commencement of the infusion were 14.5, 3.1, and 2.8 micrograms/g, respectively, with a half-life in the beta-phase of 3.53 hours. 4. Among the patients undergone thoracotomy with use of CZON, no postoperative infections occurred nor severe adverse reaction was observed. CZON attained good transfer in the pulmonary tissues, particularly in the bronchiolar tissue, hence it appears useful as a prophylactic against postoperative infections in respiratory disease.

Aged↗
PubMed1989

[Inhalation of a precursor analogue of vasoactive intestinal polypeptide (Leu17 VIP-Gly-Lys) protects ascaris-induced bronchoconstriction in dog].

We studied in vivo the effects of pre-inhalations of vasoactive intestinal polypeptide (VIP) and a precursor analogue of VIP (Leu17 VIP-Gly-Lys: preVIP) in mongrel dogs bronchoconstricted by ascaris. An inhalation of preVIP solution (2 mg/5 ml saline) gave significant protection for 120 min against increases in respiratory resistance (Rrs) and decreases in dynamic compliance (Cdyn) induced by ascaris challenges. An inhalation of VIP solution (2 mg/ml saline) also gave significant protection for 120 min against increases in Rrs induced by ascaris challenges. Protective effect of the inhalation of preVIP against ascaris-induced bronchoconstriction was more potent than that of VIP. The inhalations of preVIP and VIP solution did not change systemic blood pressure or heart rate. These results indicate that inhalations of preVIP or VIP solution would attenuate ascaris-induced bronchoconstriction in dogs without affecting cardiovascular dynamics.

Administration, Inhalation↗
PubMed1989

[The role of protein kinase C in left ventricular relaxation impaired by global ischemia].

The role of protein kinase C (C kinase) in the left ventricular relaxation impaired by global ischemia was investigated in anesthetised dogs. Left ventricular global ischemia model was made by coronary blood flow reduction and atrial pacing (100-180 beats/min). By this maneuver, the time constant T and left ventricular end-diastolic pressure (LVEDP) were increased in a pacing-rate dependent manner. Intracoronary infusion of H-7, an inhibitor of C kinase, suppressed the magnitudes of the increments of T and LVEDP, while intracoronary infusion of 12-O-tetradecanoyl-phorbol-13-acetate, an activator of C kinase, enhanced the increases of T and LVEDP caused by ischemia. In non-ischemic group, H-7 did not influenced T and LVEDP. The results indicate that C kinase is activated by myocardial ischemia and enhances impairment of left ventricular relaxation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

[Investigation on antibodies to human T cell leukemia virus type I in patients with primary glomerulonephritis].

We investigated on antibodies to human T cell leukemia virus type I (anti HTLV-I) in 101 patients with primary glomerulonephritis in Kagoshima prefecture, an endemic area of HTLV-I in Japan. The positive rate in patients with primary glomerulonephritis was 17.8%, which was not significantly higher than in healthy residents 4741 persons of 11.9% in the same area. Classified by renal biopsy findings, the positive rate in patients with membranous nephropathy was 21.4% (9/42), minimal change nephrotic syndrome 14.3% (2/14), IgA nephropathy 15.4% (2/26), and others 15.8% (3/19) respectively, which were not significantly differed from that in healthy residents. Positivity of aged patients (60 years or over) in membranous nephropathy on the contrary was significantly higher than that in healthy residents (p less than 0.01). Further study is required to clarify the relationship between HTLV-I infection and glomerulonephritis.

Adolescent↗
PubMed1989

[Anemia in patients on continuous ambulatory peritoneal dialysis (CAPD)].

Inhibitors of erythropoiesis found in the blood of uremic patients have been implicated as some of the causes of anemia in chronic renal failure. As a treatment to remove the inhibitors, continuous ambulatory peritoneal dialysis (CAPD) is thought to be more effective than hemodialysis. Some researchers have reported that CAPD has improved anemic state in hemodialysis patients. However, there have been some cases of severe anemia seen in CAPD patients. To access the effect of the CAPD, we have performed serial examination on hemoglobin (Hb) and hematocrit (Ht) in 5 uremic patients under CAPD treatment. Hb levels in 4 and Ht in 3 of 5 patients have been known to be increased. One patient was shown to have no increment on the levels of Hb and Ht. On the other hand, further investigation has been down to access the effect of the recombinant human erythropoietin (r-HuEPO: Chugai pharmaceutical) on anemic patients, in whom no effect was noticed by treatment of CAPD. One severe anemic patient, who had been undergoing the treatment of CAPD for two years, was given r-HuEPO intravenously. The patient showed the increment on the levels of Hb and Ht, and the decreases on the levels of serum iron and ferritin. However, the patient has developed hypertension. In conclusion, CAPD was known to be not always effective for the increment of Hb and Ht, while r-HuEPO was very effective for the improvement of severe anemia in CAPD patients which enabls them to lead better social life for them.

Adult↗
PubMed1988

Lactate dehydrogenase isoenzymes are present in matrix vesicles.

Matrix vesicles were isolated from epiphyseal growth plates of young rabbits. Lactate dehydrogenase activity was detected in the isolated matrix vesicles only in the presence of detergents, suggesting that NADH, the cofactor for the assay, does not penetrate the membrane of matrix vesicles. In contrast, the activity of alkaline phosphatase, a marker enzyme of the outer surface of matrix vesicles, was detected in the matrix vesicles using p-nitrophenyl phosphate as the substrate both in the presence and absence of detergents. Lactate dehydrogenase activity was detected only in the cytosol of chondrocytes of the epiphyseal growth plates but not in other subcellular fractions, showing that lactate dehydrogenase is not from the plasma membrane and membranes of intracellular organelles of chondrocytes. The isolated matrix vesicles contained all five lactate dehydrogenase isoenzymes but did not possess other cytosolic enzymes. These results show that lactate dehydrogenase is located in the matrix vesicles and suggest the presence of a mechanism for the specific uptake of cytosolic lactate dehydrogenase and the possibility of enzymatic quantification of the matrix vesicles at various calcification sites.

Animals↗
PubMed1988

Centrally administered thyrotropin-releasing hormone in the regulation of regional blood flow to brown adipose tissue in rats.

The effects of thyrotropin-releasing hormone (TRH) administered via the lateral ventricle on the blood flow to the interscapular brown adipose tissue (IBAT) was studied in urethane anaesthetized rats. TRH in i.c.v. doses of 50 or 5 micrograms/kg produced a significant and transient decrease in IBAT blood flow. The effect of 5 micrograms/kg TRH was blocked by bilateral surgical denervation. TRH caused a comparable decrease in blood flow to both the innervated pad of unilaterally denervated rats and the intact pads of non-operated rats whereas no response to TRH was observed in the denervated pad. Adrenal demedullation partly inhibited but did not completely abolish the effect of TRH on IBAT blood flow and lessened the increase in serum adrenaline caused by TRH. The effect of TRH was dose dependently suppressed by pretreatment with prazosin 15 min prior to TRH. Yohimbine did not influence the effect of TRH on IBAT blood flow. Central administration of TRH affects the regional blood flow to IBAT and appears to interfere with neural mechanisms that involve mediation by the alpha 1-adrenoceptors on the vasculature. The effect is in part due to circulating adrenaline from the adrenal medulla.

Adipose Tissue, Brown↗
PubMed1988

Alzheimer's disease brain extract stimulates the survival of cerebral cortical neurons from neonatal rats.

Cell cultures of neonatal rat cerebral cortex in a serum-free medium were used to investigate a lack of neuronotrophic factors in Alzheimer's disease (AD) brain. A few neurons survived in the absence of brain extract. The addition of normal brain extract resulted in a 2.5-fold increase in neuronal survival. AD brain extract contained 4-fold neuronotrophic activity of normal brain extract. These findings are in contrary to the previous hypothesis of a lacking neuronotrophic factors in AD brain. These new results may change the concept of mechanism of neuronal death in AD.

Aged↗
PubMed1988

Percutaneous pulmonary angioscopy using a guiding balloon catheter.

The applicability of angioscopy for observation of the pulmonary arterial lumen was examined in 7 anesthetized dogs and in 10 patients with various heart diseases during cardiac catheterization. A novel guiding balloon catheter (#11F shaft diameter and 1.5 cm in balloon diameter) was introduced through the right femoral vein into the pulmonary artery by Seldinger's method. Then, a fiberscope (1.3 or 1.8 mm in diameter) was introduced through the guiding catheter into the desired portion of the artery. The balloon was inflated, saline was infused, and the pulmonary arterial lumen was photographed on 16-mm color cinefilms. In all dogs and patients examined, an increase in diameter of the pulmonary artery during systole and the backflow of blood from the pulmonary vein were clearly demonstrated. Also, pulmonary thrombi or emboli experimentally induced in dogs could be observed. No complications were observed in the patients. The results indicate the experimental and clinical applicability of angioscopy using a guiding balloon catheter for observation of the pulmonary arterial lumen.

Adult↗