Search PubMed⌕ Search

Biomedical subjects

I Ninomiya

Publications and source records attributed to I Ninomiya.

At least 73 records · Page 4Linked to original sources
PubMed1994

beta-Adrenergic mechanisms attenuated hypoxic pulmonary vasoconstriction during systemic hypoxia in cats.

In this study, we examined how locally mediated hypoxic pulmonary vasoconstriction is modulated by autonomic nervous system activation during global alveolar hypoxia (GAH) accompanied by systemic hypoxemia. Using an X-ray television system on the in vivo cat lung, we measured changes in the internal diameter (ID) during GAH and regional alveolar hypoxia (RAH) without systemic hypoxemia in identical small pulmonary arteries and veins (100-600 microns ID). We also analyzed the effects of the autonomic nervous system blockade on the hypoxic ID changes. During GAH the ID of the arteries reduced by 5 +/- 1 and 3 +/- 1% with 10 and 5% O2 inhalations, respectively, whereas during RAH the arterial ID reduced by 12 +/- 1 and 18 +/- 1% with 10 and 5% O2 inhalations, respectively. The magnitude of the ID reduction was significantly smaller during GAH than during RAH. After pretreatment with propranolol, however, GAH induced large ID reductions (16 +/- 1 and 23 +/- 1% with 10 and 5% O2 inhalations) with patterns very similar to those seen during RAH. Phentolamine and atropine had no effect on the response during GAH. The ID reductions during RAH, on the other hand, were unaffected by all the blockers. The results indicate that, in the cat, alveolar hypoxia per se acts locally to constrict the small pulmonary vessels and that the hypoxic vasoconstriction is attenuated by a beta-receptor-mediated vasodilator effect during GAH with systemic hypoxemia. In addition, we found that, after adrenalectomy plus ganglion blockade with hexamethonium bromide, the GAH-induced ID reduction with 5% O2 inhalation was enhanced from 3 to 19%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1994

[Dual arterial infusion chemotherapy, continuous hyperthermic peritoneal perfusion, and total parietal peritonectomy for peritoneal dissemination in gastric cancer--a case report].

A 36-year-old man developed massive ascites, of which cytology proved Class V, and upper gastrointestinal endoscopy disclosed Borrmann type 4 gastric cancer. We performed dual arterial infusion chemotherapy (DAIC) through the celiac axis and superior mesenteric artery, followed by the operation including continuous hyperthermic peritoneal perfusion, total gastrectomy, subtotal colectomy, massive intestinal resection, splenectomy, cholecystectomy, appendectomy, and total parietal peritonectomy (TPP). Ascites disappeared and the CA125 level was normalized by DAIC. This operation was well tolerated. Though the histopathological study revealed multiple peritoneal disseminations on the visceral peritoneum of stomach, small intestine, colon, and parietal peritoneum such as Douglas' pouch, there were denatured cancer cells in the visceral peritoneum to which blood supply under DAIC was distributed. These results suggested the effect of neoadjuvant DAIC and the significance of TPP.

Adult↗
PubMed1994

Lymph node metastases from carcinoma of the gastric stump.

The incidence of metastases from gastric stump cancer to various regional lymph node stations was studied after meticulous node dissection in 87 patients, who had undergone curative resection. Fifty-five (63%) patients had microscopically involved nodes. The incidence of node metastases varied between 17% and 30% in the perigastric nodes (n 1), with the same incidence in second-station lymph nodes (n 2; nodes along the left gastric, common hepatic and splenic artery, or nodes at the splenic hilus) With respect to third-station lymph nodes (n 3), metastases in nodes in the hepatoduodenal ligament (No 12) and retropancreatic nodes (No 13) were found only in 2% and 8% of the cases, respectively, but there was a high incidence of metastases (14/54, 31%) in the nodes along the mesenteric root. The overall 5-year survival rate was 48% and those for n 1 and n 2 patients were 78%, and 41%, respectively. With regard to the third level lymph node station, no 5-year survivors were seen when there was nodal involvement in node station No. 12 or No. 13. However, involvement of nodes at the root of the mesentery was associated with a 5-year survival rate of 25%. These results suggest that resection of the second level lymph nodes station must be combined with total gastrectomy and distal pancreatectomy, and that the resection of the mesenteric root is very important in patients with a tumor invading the jejunum.

Female↗
PubMed1994

A new surgical technique (left upper abdominal evisceration) for advanced carcinoma of the gastric stump.

In spite of recent advances in the early diagnosis of gastric cancer by mass screening, gastric stump cancers following gastrectomy are still diagnosed at a highly advanced stage, and the surgical results remain very poor. Involvement of the fourth level lymph node stations, local peritoneal carcinomatosis and tumor growth invading the neighboring organs are frequently observed in advanced stump cancers. With the aim of achieving complete resection of these tumors, left upper abdominal evisceration (LUAE) + R4 gastrectomy was performed in 29 patients (Group B) with stump cancer as a radical surgical procedure. The survival of these patients was compared with that of 74 patients (Group A) who underwent total gastrectomy with or without pancreaticosplenectomy. Duration of surgery blood loss, and incidence of postoperative complications were similar with the two methods. When the survival rates were compared, the 5-year-survival rate in stage IV cases was higher for Group B than for Group A. LUAE + R4 gastrectomy is a rational technique for the surgical treatment of stage IV gastric stump cancer.

Adrenalectomy↗
PubMed1993

Metabolism and distribution in the rat of peak E substance, a constituent in L-tryptophan product implicated in eosinophilia-myalgia syndrome.

Peak E substance, 1,1'-ethylidenebis[tryptophan], a contaminant found in L-tryptophan tablets, has been suggested as a causative agent for eosinophilia-myalgia syndrome (EMS). Peak E substance (50 mg/kg) was administered perorally to Wistar rats to determine its metabolism and distribution. A purification procedure using Bond Elut C8 cartridges followed by HPLC was developed for the determination of peak E substance. The plasma concentration of peak E substance was 136 ng/ml at 1 h, and urinary excretion was 717 ng at 5 h and 10342 ng for 5-24 h, showing slow excretion of peak E substance into urine. The amount of peak E substance in the contents of the large intestine at 5 h, however, was 3136 micrograms, much greater than urinary excretion for 24 h, indicating considerable transfer of peak E substance to large intestine without decomposition by gastric fluid in the stomach. We have detected for the first time not only the occurrence of peak E substance in plasma and urine, but also 1-methyl-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) in blood and organs of rats treated with peak E substance, thereby suggesting MTCA as one of the the metabolites of peak E substance. The amount of MTCA in the contents of the large intestine as well as in urine of rats treated with peak E substance was significantly greater than in L-tryptophan-treated rats (50 mg/kg p.o.), demonstrating that MTCA was more readily produced from peak E substance than from L-tryptophan. Finally, we propose acetaldehyde-induced production of MTCA from peak E substance.

Animals↗
PubMed1993

The amplitude of synchronized cardiac sympathetic nerve activity reflects the number of activated pre- and postganglionic fibers in anesthetized cats.

In order to obtain information regarding the number of pre- and postganglionic fibers that are firing, we measured cardiac sympathetic nerve activity (CSNA) before and after the successive sectioning of T1-T5 thoracic rami in anesthetized cats. Total activity from the area was measured under the mean CSNA curve. Peak amplitude, width and periodicity of the synchronized discharge was analyzed from the CSNA curve by the method we developed. Total CSNA decreased to 91 +/- 6%, 63 +/- 6%, 27 +/- 10%, 8 +/- 6% and < 1% of the control due to successive section of the T5, T4, T3, T2 and T1 rami, respectively. The peak amplitude of synchronized CSNA decreased to 95 +/- 6%, 73 +/- 8%, 40 +/- 5% and < 10% of the control value, due to section of the T5, T4, T3 and T2 rami, respectively. The control width was 107 +/- 8 ms and decreased to 106 +/- 1 ms, 92 +/- 6 ms and 68 +/- 5 ms by successive section of the respective T5, T4 and T3 rami. However, periodicities of 80-120 ms (Tc rhythm) and 140-500 ms (Tb rhythm) of synchronized CSNA remained unchanged after section of the T3-T5 rami. The total CSNA decreased gradually due to decreases in the peak amplitude and width of synchronized CSNA with the successive section of preganglionic fibers. These results indicate that the peak amplitude of synchronized CSNA reflects the number of pre- and post-ganglionic fibers that are firing and suggest that the number of preganglionic neurons which activate the cardiac fibers naturally was largest in the T3 segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1993

Differential regional responses of myocardial interstitial noradrenaline levels to coronary occlusion.

OBJECTIVE: The aim was to investigate the influence of coronary occlusion on myocardial interstitial noradrenaline levels in the ischaemic and non-ischaemic regions, using the dialysis technique. METHODS: In nine anaesthetised cats, regional ischaemia was produced by occlusion of the left anterior descending coronary artery for 90 min. Using the dialysis technique, dialysates were sampled from both the ischaemic region and the nonischaemic left circumflex coronary artery region. Dialysate noradrenaline concentrations, as an index of myocardial interstitial noradrenaline content, were measured by high performance liquid chromatography. Myocardial blood flows in the ischaemic and non-ischaemic regions were measured by the hydrogen clearance method. RESULTS: In the non-ischaemic region, neither myocardial blood flow nor dialysate noradrenaline concentration showed significant change. In the ischaemic region, myocardial blood flow decreased significantly, from 117(SEM 12) at control to 23(3) ml.min-1 x 100 g-1, and dialysate noradrenaline concentration increased significantly, from 56.8(4.5) pg.ml-1 at control to 528.8(155.4) pg.ml-1 at 0-30 min of occlusion, 4212.0(1447.7) pg.ml-1 at 30-60 min, and 4179.8(1668.5) pg.ml-1 at 60-90 min. At 0-30 min of the reperfusion period, dialysate noradrenaline concentration in the postischaemic region decreased significantly to 420.2(152.1) pg.ml-1. CONCLUSIONS: Coronary occlusion increased myocardial interstitial noradrenaline levels in the ischaemic region, but not in the non-ischaemic region.

Animals↗
PubMed1993

Noradrenaline contributes to modulation of the carotid sinus baroreflex in the nucleus tractus solitarii area in the rabbit.

The authors examined the contribution of the noradrenergic system to central cardiovascular regulation in the dorso-medial region of the medulla oblongata, including the nucleus tractus solitarii (NTS) area, in anaesthetized rabbits. First, to determine the modulation of the carotid sinus baroreflex system by alpha-blocker, which blocks the action of noradrenaline, the open loop relationship between isolated carotid sinus pressure (CSP) and renal nerve activity (RNA) was examined before and after injection of alpha-blocker (phentolamine, 10 micrograms, bilateral). alpha-Blocker injected to the NTS area caused a decrease in RNA at low CSP level (40-50 mmHg), and RNA response remained higher at high CSP levels (130 mmHg), in comparison with control. Baroreflex sensitivity was attenuated significantly from 10.9 +/- 2.2 to 5.0 +/- 0.5% (mmHg-1). The data show that the NTS area is one of the important sites in central modulation of the carotid sinus baroreflex function. It is suggested that the noradrenergic system in the NTS area contributed to facilitating carotid sinus baroreflex function. Second, using the dialysis technique, a dialysis probe was implanted in the dorso-medial region of the medulla oblongata, including the NTS area, and perfused with Ringer's solution. Dialysates were collected from this region and noradrenaline (NA) output was determined by high-performance liquid chromatography/electrochemical methods. Drug-induced hypotension caused a 30% decrease in arterial pressure and an increase in dialysate NA levels from 6.8 +/- 0.2 to 9.0 +/- 0.4 pg sample-1. The results show that noradrenaline in the NTS area is involved in the regulation of arterial pressure through the central modulation of arterial baroreflex function.

Animals↗
PubMed1993

Effects of anesthesia on cardiac and renal sympathetic nerve activities and plasma catecholamines.

The effects of pentobarbital and chloralose on cardiac sympathetic nerve activity (CSNA), renal sympathetic nerve activity (RSNA), arterial pressure (AP), and heart rate (HR) were examined using conscious cats. Arterial blood was sampled intermittently to measure plasma epinephrine. Pentobarbital (25-30 mg/kg iv) decreased CSNA, RSNA, AP, and HR. The reduction of CSNA (71 +/- 7%) was larger and lasted longer than that of RSNA (33 +/- 12%). Chloralose (40-50 mg/kg iv) decreased CSNA 66 +/- 9% and HR, increased RSNA 127 +/- 122%, and did not affect AP. The baroreflex relationship between AP and CSNA was examined by increasing AP to 145 mmHg and decreasing AP to 55 mmHg. Both pentobarbital and chloralose shifted the AP-CSNA relationship curve downward and blunted the slope of the curve, indicating that both drugs attenuate tonic and baroreflex cardiac sympathetic outflow. Pentobarbital and chloralose reduced plasma epinephrine, suggesting a decrease in adrenal sympathetic nerve activity. It is concluded that pentobarbital or chloralose affects differentially sympathetic outflows to different organs such as the heart, kidney, and adrenal gland.

Anesthesia↗
PubMed1993

Nitric oxide mediates cat hindlimb cholinergic vasodilation induced by stimulation of posterior hypothalamus.

The aim of this work was to examine whether endothelium-derived relaxing factor (nitric oxide) mediates cat hindlimb cholinergic vasodilation induced by stimulation of the posterior hypothalamus and beta-adrenergic vasodilation by I.V. injection of isoproterenol using an inhibitor of nitric oxide synthesis, NW-nitro-L-arginine methyl ester (L-NAME). Without L-NAME, femoral blood flow velocity (FBV) increased during hypothalamic stimulation by 11.2 +/- 2.2 cm/s (mean +/- SEM) from the baseline value of 8.4 +/- 2.2 cm/s and femoral conductance (FC) increased by 0.084 +/- 0.021 cm/s/mmHg from 0.062 +/- 0.016 cm/s/mmHg, which were abolished by atropine (0.5 mg I.A.). Arterial blood pressure (AP) and heart rate (HR) increased during hypothalamic stimulation (15 +/- 8 mmHg and 22 +/- 6 beats/min). When isoproterenol (1-2 micrograms I.V.) was injected, FBV and FC increased 5.1 +/- 0.56 cm/s and 0.048 +/- 0.005 cm/s/mmHg. With L-NAME (20-100 mg I.A.), the rises in AP and HR during hypothalamic stimulation were unchanged but the increases in FBV and FC were significantly blunted to 5.2 +/- 3.7 cm/s and 0.026 +/- 0.021 cm/s/mmHg. In contrast, L-NAME did not affect the responses in FBV and FC during stimulation of beta-adrenergic receptors. The effect of NG-monomethyl-L-arginine (10-30 mg I.A.) was the same as L-NAME. It is suggested that nitric oxide is involved in hindlimb cholinergic vasodilation neurally induced by hypothalamic stimulation but not in beta-adrenergic vasodilation.

Animals↗
PubMed1993

Selective and tone-dependent vasodilation of arterial segment in rabbit and feline pulmonary microcirculation in response to ANP.

Using an X-ray television system, we directly measured the changes in internal diameter (ID; 100-600 microns) of small pulmonary arteries and veins in response to intravenous infusion of atrial natriuretic peptide (ANP) in anesthetized rabbits and cats. Under physiological conditions, ANP (0.01-1 micrograms/(kg.min) for 3 min) increased the ID of the small arteries in a dose-dependent manner by 4-9% and by 6-14% in the rabbit and cat, respectively. The maximum increase in ID occurred in the 400-600 microns arteries. In the small veins, however, the peptide had no significant effects on the ID. To simultaneously investigate the ANP-induced responses of pulmonary vessels with different vascular tone in a given lung region, we embolized a part of the rabbit pulmonary vascular tree with micro-beads (80-100 microns diameter) and measured ID responses to ANP (1 microgram/(kg.min) for 3 min) in the embolized vessels with elevated tone and the nonembolized vessels with baseline tone. In the embolized arteries, which had constricted by 31%, ANP induced 27% increase in ID, while in the nonembolized arteries it caused 8% increase in ID. This indicated that in the small arteries, the vasodilator activity of ANP is greatly enhanced under the conditions of elevated vascular tone. In the small veins, however, no significant vasodilation occurred even under the elevated-tone conditions. We concluded that ANP dilates the arterial segments in the rabbit and cat pulmonary microcirculation selectively and in a dose-dependent manner. Furthermore, the pulmonary vasodilator effect of ANP was dependent on the pulmonary vascular tone.

Animals↗
PubMed1993

[Correlation of DNA ploidy, c-erbB-2 protein tissue status, level of PCNA expression and clinical outcome in gastric carcinomas].

One-hundred and sixty-four patients with gastric carcinomas, who underwent gastrectomy during 1979-1985, were studied. Sixty-five of these cases were early gastric carcinomas, and the others were advanced gastric carcinomas, and the others were advanced gastric carcinomas. The nuclear DNA contents were measured by cytofluorometry, and immunohistochemical study on the expression of c-erbB-2 protein was performed using a monoclonal antibody against the c-erbB-2 oncogene product. Furthermore, immunohistochemical detection of proliferating cell nuclear antigen (PCNA) was performed using a monoclonal antibody against the PCNA. The rates of positive invasion beyond submucosal layer, lymphatic invasion, and vascular invasion in aneuploid cases were significantly higher than those in diploid ones, and the patients with aneuploid tumor had a significantly worse prognosis than those with diploid tumor. The rates of positive lymph node metastases and invasion beyond submucosal layer in the group with positive staining of the c-erbB-2 protein was significantly higher than in the negative group, and the group with positive staining for c-erbB-2 had a significantly worse prognosis than the negative one. PCNA indices showed a significant correlation with lymph node metastasis, and the group with higher PCNA indices had a worse prognosis. The patients with tumor showing both aneuploid and positive staining for c-erbB-2 protein, had the worst prognosis. There is a relationship between c-erbB-2 tissue status and PCNA indices, but no correlations were found among c-erbB-2 tissue status, PCNA indices and DNA contents. From these results, it can be concluded that DNA ploidy, c-erbB-2 protein, and PCNA may reflect the malignant potential of gastric carcinoma.

Antibodies, Monoclonal↗
PubMed1993

Correlation of p53 expression and proliferative activity in gastric cancer.

We analyzed immunohistochemically the association between p53 tissue status and prognostic parameters of 357 gastric cancer patients, using endoscopically obtained biopsy materials, embedded in paraffin. Using PAb1801, an anti-p53 monoclonal antibody p53 immunoreactivity was detected in the nuclei of cancer cells in 113 cases (32%). The nuclear p53 immunoreaction was closely associated with positive lymph node metastasis, serosal invasion, and liver metastasis. For the estimation of proliferative activity, proliferating cell nuclear antigen (PCNA) labeling rates (LRs) of biopsy specimens were immunohistochemically measured. A significant positive correlation was found between PCNA LRs and p53 tissue status. In addition, a positive nuclear p53 immunoreaction was found to be significantly associated with shorter overall survival. Especially, in the group of patients with stages III and IV, the prognosis of patients with p53-positive tumours was significantly poorer than that of patients with p53-negative tumours. These results indicate that immunohistochemical staining for nuclear p53 in biopsied materials may be useful in deciding the therapeutic schedule of patients with gastric cancer, preoperatively.

Antibodies, Monoclonal↗
PubMed1992

Independent clinical and flow cytometric prognostic factors for the survival of patients with stage I gastric cancer.

Paraffin-embedded tumor samples from 151 patients with stage I gastric cancer were analyzed by DNA flow cytometry, and 80 patients received an infusion of bromodeoxyuridine (BrdU) to determine S-phase fraction. S-phase fractions of tumors were measured by the immunohistochemical method using anti-BrdU monoclonal antibody. Of the 151 patients, 81 (54%), and 70 (46%) showed diploid and aneuploid patterns. There was no significant association between DNA ploidy and wall invasion, histologic type, or lymphatic invasion. Aneuploid tumors were associated with positive-vessel invasion. When the DNA ploidy and clinicopathological parameters were simultaneously entered into the Cox regression model, DNA ploidy and wall invasion emerged as independent prognostic parameters. Aneuploid tumors had significantly higher values of BrdU labeling indices than diploid ones. These results indicate that the determination of DNA ploidy patterns may be an important prognostic factor in patients with stage I gastric cancer, and may be useful in deciding the therapeutic schedule of patients with gastric cancer.

Aneuploidy↗
PubMed1992

The succinate dehydrogenase inhibition test for evaluating biopsy specimens and resected tumors of advanced gastric cancer.

An in vitro chemosensitivity study of both biopsy specimens and surgically resected tumors of advanced gastric cancer from 12 patients was evaluated using the succinate dehydrogenase inhibition (SDI) test. A decrease in succinate dehydrogenase (SD) activity as an indicator of chemosensitivity was determined using cisplatin (CDDP), etoposide (VP-16), and mitomycin C (MMC). In this study, 29 of a total 36 experiments were evaluable (80.6%) and significant correlations were found in all three of the antitumor drugs (P < 0.03). This finding suggests that the SDI test using biopsy specimens may prove valuable for assessing the preoperative chemosensitivity of advanced gastric cancer.

Aged↗
PubMed1992

Fundamental rhythm of renal sympathetic nerve activity in anesthetized cats.

To examine the fundamental rhythms of sympathetic discharges, the periodicity of synchronized renal nerve activity (RNA) was measured in anesthetized cats. After filtering the RNA between 50-3000 Hz, rectification and integration the periodicity was calculated by measuring the peak to peak intervals. Two major periodicities were detected, a Tc rhythm between 6 and 25 c/s with a 43% probability and a Tb rhythm between 2 and 6 c/s with a 57% probability. The mean periods of Tc and Tb were 95 +/- 2 ms and 297 +/- 4 ms (+/- SE) respectively. Another techniques which has previously been used to assess the periodicity was also applied, in which the original neurogram was filtered between 0.08-3000 Hz and measured by power spectral analysis. However, this technique only identified the 2-6 c/s frequency and the faster Tc rhythm was undetected. Baroreceptor stimulation induced by noradrenaline decreased the probability of Tc and Tb modal components. Baroreceptor denervation led to an increase in the probability of the Tc rhythm and reduction in the Tb rhythm. These results support our model that the Tc rhythm reflects a fundamental periodicity of central origin and that the Tb rhythm reflects a periodicity of cardiac-related RNA, which is produced by reflex inhibition of the fundamental rhythm by periodic baroreceptor input.

Anesthesia↗
PubMed1992

Effect of chemoreceptor stimulation on the periodicity of renal sympathetic nerve activity in anesthetized cats.

The effect of chemoreceptor stimulation, with asphyxia (1 min), hypoxia (2 min) or hypercapnia (2 min), on the periodicity of synchronized renal sympathetic nerve activity (RNA) was examined in anesthetized cats before and after peripheral chemoreceptor and baroreceptor denervation. RNA was filtered between 50-3000 Hz, rectified and integrated. Time intervals, less than 500 ms, between synchronized interburst intervals were measured and used to produce periodicity histograms. Under control normoxia two major periodicities were evident, a Tc rhythm between 6 and 17 c/s comprising 34 +/- 5% (+/- SE) of measured intervals and a Tb rhythm between 2 and 6 c/s with a 66% probability. The mean periods of Tc and Tb were 110 +/- 6 ms and 299 +/- 7 ms respectively. The periodicity distribution and mean Tc and Tb rhythms for RNA discharge under various chemoreceptor stimulations were not significantly changed despite significant increases in arterial blood pressure in all cases. The amplitude and overall number of synchronized RNA peaks were however increased with chemoreceptor stimulation. When asphyxia was applied under a constant arterial pressure the periodicity of synchronized RNA still was not significantly altered. Baroreceptor and peripheral chemoreceptor denervation led to an increase in the probability of the Tc mode and reduction in the Tb mode, once again the application of chemoreceptor stimulation did not significantly alter the frequency distribution of synchronized RNA. The results indicate that chemoreceptor stimulation does not affect the 10 c/s fundamental rhythm and the stability of gate operators altering Tc/Tb proportions, although it can alter the number of active fibres and interacts with the baroreflexes to maintain RNA at elevated blood pressures. The results support our model that the Tc mode reflects a fundamental periodicity of central origin and the Tb mode a periodicity of cardiac related RNA, which is produced by the opening and closing of gate operators to the fundamental rhythm.

Anesthesia↗