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Biomedical subjects

Y Shimada

Publications and source records attributed to Y Shimada.

At least 523 records · Page 29Linked to original sources
PubMed1991

Atrial natriuretic polypeptide secretion via selective activation of kappa-opioid receptor: role of dynorphin.

The present study was designed to investigate the direct effect of dynorphin on atrial natriuretic polypeptide (ANP) secretion in cultured rat atrial cardiocytes via a kappa-opioid receptor activation as well as the involvement of adenosine 3',5'-cyclic monophosphate (cAMP) system in the secretion of ANP from cardiocytes. Dynorphin stimulated ANP secretion dose and time dependently from 2-day cultured atrial cardiocytes. The dynorphin-induced ANP secretion was partially antagonized by MR2266, a selective kappa-opioid receptor antagonist. U-62066E, a selective kappa-opioid receptor agonist, stimulated ANP secretion. This stimulation was also antagonized by MR2266. However, no stimulation of ANP secretion was seen with [D-Ala2,D-Leu5]enkephalin, methionine (Met)-enkephalin, or [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin. Dynorphin at 10(-6) M significantly decreased the production of cAMP in the cultured cardiocytes. However, 10(-6) M Met-enkephalin had no effect on cAMP at all. The decrease in cAMP production by the addition of dynorphin was partially antagonized with a simultaneous addition of MR2266. The dynorphin-induced ANP secretion, as well as the basal secretion, were significantly decreased by the addition of 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, as compared with the respective controls. Dibutyryl cAMP at 10(-3) M significantly decreased the basal secretion of ANP as compared with the control. Therefore, the present studies show that dynorphin selectively stimulates ANP secretion, at least in part, via the activation of a specific kappa-opioid receptor.

1-Methyl-3-isobutylxanthine↗
PubMed1991

Lung vascular permeability enhanced by sympathetic nerve stimulation in rats.

Role of sympathetic nerves in increasing the lung vascular permeability was investigated in the presence of papaverine using an isolated rat lung perfusion preparation. Sympathetic nerve stimulation was performed at different time points before and after pressure-induced weight gain. When stimulated at 3 or 7 min after the pressure associated increment, stimulation evoked a further increase in lung weight, particularly in the former case. In contrast, stimulation performed before or 15 min after the pressure increment elicited no such response. The histological finding of carbon particles in the perivascular wall after sympathetic nerve stimulation also provided direct evidence of increased lung vascular permeability.

Animals↗
PubMed1991

Effects of isoprothiolane and phytosterol on adipocyte metabolism and fatty acid composition of serum and tissue lipids in rats.

Isoprothiolane at a dose of 250 mg/kg or phytosterol 50 mg/kg was orally administered to rats once a day for 2 weeks. Basal [U-14C]glucose conversion rate to total lipids in isolated adipocytes of the rats was significantly decreased by treatment with isoprothiolane (54%) or phytosterol (82%). Adipocytes from the rats with isoprothiolane released less glycerol than those from control rats only at an epinephrine concentration of 10 microM. The serum level of total cholesterol was depressed by phytosterol ingestion. The level of non-esterified fatty acids (NEFA) was increased by isoprothiolane. Desaturation in fatty acid composition of phospholipid or cholesterol ester was observed in serum, liver and adipose tissue of the rats treated with either drug. These results suggest that either drug may have common effects by preventing lipid deposition into adipocytes and accelerating fatty acid desaturation in tissue lipids.

Adipose Tissue↗
PubMed1991

Determination of the optimal pressure support level evaluated by measuring transdiaphragmatic pressure.

The purpose of this study was to determine the optimum pressure support (PS) in six patients with respiratory failure. Esophageal pressure (Pe), gastric pressure (Pg), airway pressure, and transdiaphragmatic pressure (Pdi), obtained by subtracting Pe from Pg, were measured using a newly developed multiluminal nasogastric catheter. For each patient, different PS levels were selected every 20 minutes, and measurements were made at each PS level. We defined the optimum PS level as the level that showed the minimum Pe value. Respiratory rate (RR) decreased and tidal volume (VT) increased with an increase in PS level. RR and VT at the optimum PS were 19.7 +/- 5.5 breaths per minute and 11.7 +/- 4.5 ml/kg, respectively. Pdi decreased linearly with increasing PS level in all patients. Mean Pdi at the optimum Ps was 4.2 +/- 1.2 cm H2O. Based on the relationship between Pdi and PS level, we constructed an equation to estimate the optimum PS level as follows: Optimum PS level = [( Pdi during T-piece mode] - 4)/0.8. We conclude that Pdi measurement is helpful for titrating the required PS level.

Adult↗
PubMed1991

Comparison of inspiratory work of breathing in T-piece breathing, PSV, and pleural pressure support ventilation (PPSV).

We have compared the inspiratory work of breathing during T-piece breathing, pressure support ventilation (PSV), and pleural pressure support ventilation (PPSV) by using a lung model with variable compliance and resistance, under simulated spontaneous breathing. Our lung model consists of two spring-loaded bellows, representing the lung and diaphragm, placed in an airtight container. Inspiration begins with the withdrawal of air from the diaphragm bellows by a time-cycled jet-flow-creating Venturi mechanism. Expiration occurs by opening the diaphragm bellows to the atmosphere. Work of breathing (WOB) is calculated by plotting the pressure-volume curve, with pressure corresponding to intrabox pressure and volume corresponding to the tidal volume; PPSV is a new mode of mechanical ventilatory support accomplished by setting the ventilator (Servo 900C) into the PSV mode with a level of 0 cm H2O, using the pleural pressure as the input and target signal. The PPSV maximally reduces WOB under any circumstances. The PSV sufficiently reduced WOB only in the normal lung and the lung with low compliance; however, a pressure supporting time is diminished in the lung with low compliance. The serious limitations of PSV remain in its application to the lung with high resistance. It is concluded that PPSV is closer to the actual patient's signal and has a potential advantage in reducing WOB in the lung with low compliance or high resistance (or both). The lung with flow limitation is still a challenging issue for mechanical ventilatory assistance.

Humans↗
PubMed1991

Cloning, nucleotide sequencing, and expression in Escherichia coli of a lipase and its activator genes from Pseudomonas sp. KWI-56.

A lipase gene (lip) and its activator gene (act) on a 2.9 kb BglII-EcoRI fragment from Pseudomonas sp. KWI-56 were cloned in Escherichia coli using pUC19 as a vector plasmid. From the sequencing results, the open reading frames of the lip and the act were found to contain 1092 and 1032 nucleotides, respectively. The act existed downstream of the lip with the same orientation. When the lip was expressed in E. coli using the lac promoter on the pUC plasmid vector, the lipase activity of E. coli carrying both the lip and the act was 200-fold greater than that carrying only the lip. This result suggested the act was important in the expression of the lip in E. coli.

Amino Acid Sequence↗
PubMed1991

Changes in mode of response to chemotherapy for hepatocellular carcinoma induced by transarterial embolization. A case report.

A 61-year-old man received systemic mitoxantrone chemotherapy following transarterial embolization of a large hepatocellular carcinoma with extensive intrahepatic, lung and bone metastases. His serum alpha-fetroprotein levels were 199,000 ng/ml prior to chemotherapy. He was given 10 mg mitoxantrone/m2 (14 mg/dose) intravenously every three weeks, and showed a rapid decrease in his serum levels of alpha-fetoprotein. There was almost complete resolution of the multiple bilateral metastatic lung nodules at five weeks and a marked decrease in the size of the intrahepatic metastatic nodules by seven weeks. The primary tumor, however, which had been previously treated by transarterial embolization, only underwent a 33% reduction in size according to WHO criteria. This occurred despite the disappearance, demonstrated by contrast enhanced computed tomography, of all viable tumor tissue. Ultrasonography also revealed only a minor regression, and could demonstrate no changes in the tumor echo pattern. The response pattern observed in this patient indicates the response to chemotherapy for hepatocellular carcinoma to be modified by prior transarterial embolization.

Carcinoma, Hepatocellular↗
PubMed1991

[Clinical evaluation of roxatidine acetate hydrochloride injection as preanesthetic medication].

The effects of single intravenous administration of roxatidine acetate hydrochloride 75 mg on the volume and pH of gastric juice were investigated in 43 patients undergoing elective surgery under general anesthesia. The drug was given 1 hour before anesthesia. The percentages of patients with gastric pH above 2.5 and gastric juice volume under 25 ml were 95.3% and 97.7% at the time of induction of anesthesia and at the time of extubation, respectively. As for overall assessment on gastric secretion, 93.0% was judged as very effective. In 2 cases, pricking sensations were observed at the time of injection, but these symptoms disappeared without any treatment within a few minutes. No other adverse reactions nor abnormal laboratory test findings were observed. In conclusion, roxatidine acetate hydrochloride administered intravenously 1 hour prior to anesthesia is thought to be useful to prevent acid aspiration pneumonitis.

Adult↗
PubMed1991

[Tumor markers--personal experience. A case of advanced extragonadal germ-cell tumor showing complete remission by high-dose combination chemotherapy with autologous bone marrow transplantation].

A twenty-four-year-old male patient with stage III advanced extragonadal germ-cell tumor obtained complete remission after comprehensive treatment including high-dose combination chemotherapy with autologous bone marrow transplantation. He had massive tumors in cervical, mediastinal, abdominal and inguinal lymph nodes, bilateral lungs and liver. Ascites, plural effusion and pericardial effusion were also noted. Cancer cells were demonstrated from his bloody sputum, pericardial drainage and an aspirate from supraclavicular tumor. His tumor produced hCG, AFP, placental ALP and LDH, and hCG was the best marker for the diagnosis and monitoring. The initial serum hCG level was high at 460,000 mIU/ml, but fell to 13 mIU/ml after 3 courses of PVP therapy. However, it rose ten-fold in a week. After ultra-high dose combination chemotherapy with autologous BMT, the patient's hCG fell to 1.8 mIU/ml and remained at that level thereafter. He has remained well with no sign of recurrence after 25 months.

Adult↗
PubMed1991

[A case of a right-sided sigmoid colon].

During dissecting practice by students at Chiba University in 1991, a rare anomaly was found in a cadaver of a 50-year-old Japanese male. The distal part of the colon, including the sigmoid colon, was excessively long and formed a loop behind the ascending colon. This anomalous colon consisted of four parts. The first part began in the left iliac fossa and passed across the lower posterior abdominal wall into the right iliac fossa; the second turned upward and ascended along the posterior surface of the ascending colon to the inferior surface of the right lobe of the liver; the third turned backward and descended to the right iliac fossa and was in contact with the posterior abdominal wall; the fourth curved medially and downward and ended in the rectum at the median line. Only the anterior surface of the anomalous colon was covered with the peritoneum, and its mesocolon was not found. The inferior mesenteric artery gave off four branches toward the distal three-fourths of the excessively long colon and the superior rectal artery to the upper part of the rectum. Since it did not directly give off any branches toward the descending colon and the first part of the anomalous colon (these portions were supplied by a marginal artery), the branch supplying the second part was considered to be equivalent to the left colic artery. Thus, the proximal half of the long colon (parts 1 and 2) can be regarded as a part of the descending colon, and the distal half as the sigmoid colon.(ABSTRACT TRUNCATED AT 250 WORDS)

Colon, Sigmoid↗
PubMed1991

[Protein-free culture of esophageal cancer cell lines].

We have established 13 esophageal cancer cell lines capable of growing in a protein-free environment. The growth of these cells was not affected by conditioned medium, but the growth of NIH3T3 cells and human fibroblasts was stimulated by conditioned medium. On the other hand, conditioned medium inhibited the growth of human endothelial cells. Amplified int-2 oncogene correlated well with the growth of cells in a protein-free environment but the number of EGF receptors and growth effect of EGF did not relate to such growth. Esophageal cancer cells grow automatically, possibly involving mesenchymal cells via the paracrine system. This results in a poor prognosis in patients.

Cell Division↗
PubMed1991

Electron microscopic studies on duck hepatitis B virus particles in hepatocytes and sequential changes in various patterns of infection.

To investigate the critical factors involved in the elimination of the duck hepatitis B virus (DHBV) in acute infection, the sequential changes in the number of DHBV particles in hepatocytes were studied electron microscopically in ducks experimentally infected by DHBV. Twenty Japanese white Peking ducks were infected with DHBV on the day of hatching, and on the 7th day and 14th day after hatching. Inoculation of DHBV on the day of hatching, and on the 7th and 14th day after hatching resulted in persistent viremia, transient viremia and no viremia, respectively in ducks as tested by spot hybridization assay. The number of DHBV particles in the liver correlated well with the amount of serum DHBV-DNA, DHBV particles decreased in hepatocytes without any interaction of inflammatory cells over the observation period, and the number of particles was not associated with the degree of hepatic inflammation. From these results, the elimination of the virus was thought to be induced by a reduction of viral replication in the hepatocytes and not by destruction of their host cells. There must be an age-dependent factor which strongly suppresses the viral replication.

Animals↗
PubMed1991

Heterogeneous responses of human endothelial cells to tumor necrosis factor with respect to growth inhibition.

The response of human arterial endothelial cells (ECs) to tumor necrosis factor (TNF) was compared to that of venous ECs. It was found that arterial ECs were more susceptible to TNF induced inhibition of growth and colony formation by TNF than venous ECs. In addition, synergistic effect of TNF with Interferon-gamma (IFN-gamma) was more evident in arterial ECs. Little difference, however, was identified in the characteristics of TNF receptors between arterial and venous ECs; the dissociation constant (Kd) was 0.35 nM and the number of receptors/cell was approximately 5,000. This indicates that different susceptibility of ECs to TNF is not due to these characters of TNF receptors. In conclusion, ECs are heterogeneous in the responsiveness to TNF depending on the sites of origins.

Animals↗
PubMed1991

[Cell kinetic study on the healing process of indomethacin-induced gastric mucosal lesion of rats].

In healing process of indomethacin (IND)-induced gastric mucosal lesion of rats, cell kinetics in the cells from margin of mucosal lesion, background mucosa and pyloric gland mucosa were investigated with histochemistry using bromodeoxyuridine. Results obtained were as follows; 1) In marginal cells of mucosal lesion, cell number of s-phase expressing the cell renewal abruptly increased 6 hours after IND injection, showed maximal value at 24 hours and kept higher value even at 72 hours, when the lesions were in scar stage. 2) In background mucosal cells, the cell number of s-phase showed higher value at 12 hours after IND injection, although statistically not significant, and significantly lower value at 24 and 48 hours after IND injection. 3) Some s-phase cells were observed in the surface epithelial cells covering the mucosal defect. 4) In pyloric gland mucosal cells, there was no remarkable change in cell number of s-phase during the experimental period. It was concluded that in healing process of acute gastric mucosal lesion, there was a time lag between the macroscopic observation and cell kinetics in normalization of s-phase cell number.

Animals↗
PubMed1991

[Omentum transplantation to the cervical cord with microangioanastomosis].

Transplantation of omentum to the cervical cord was done in three cases with incomplete transection (Case 1) with posttraumatic progressing cervical myelopathy (Case 2) and with complete transection due to multisegmental, late cervical cord infarction (Case 3). Anastomoses were made between the occipital artery and the gastroepiploic artery of transplanting omentum and between the occipital vein and the gastroepiploic vein. In Case 2 and 3, omentum was maintained in tissue culture medium in an incubator (37 degrees C, 5% CO2) for about five hours following perfusion of the omentum with low molecular dextran containing urokinase, heparin, vitamin B12 until exploration of the dural tube and preparation of the occipital vessels were accomplished. Although complete transection with late infarct (Case 3) showed extremely slow improvement in follow-up period of 8 months, the incomplete traumatic lesions (Case 1 and 2) showed less slow but steady improvements in follow-up periods of 24 and 22 months with almost complete recovery of Case 2. Angiography showed patent anastomosis in all the cases. Dynamic CT at 4 (Case 1) and 6 (Case 2) months showed good perfusion in the compromised cord through the transplanted omentum.

Evoked Potentials, Somatosensory↗