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Biomedical subjects

T Okamura

Publications and source records attributed to T Okamura.

At least 667 records · Page 37Linked to original sources
PubMed1986

Vascular renin-angiotensin system in two-kidney, one clip hypertensive rats.

The possible role of the renin-angiotensin system in the maintenance of hypertension in two-kidney, one clip hypertensive rats was studied. Plasma renin activity rose rapidly and markedly in association with the elevation of blood pressure and then decreased gradually, although blood pressure remained high. Renin activity in the lung, aorta, and mesenteric artery also increased with the development of hypertension and then decreased in a way similar to that of plasma renin activity at the chronic stage of hypertension. Plasma angiotensin converting enzyme activity did not change significantly until 16 weeks after unilateral renal artery clipping, whereas vascular angiotensin converting enzyme activity significantly increased at the chronic, but not the acute, stage of hypertension. In chronically renal hypertensive rats, 1-sarcosine, 8-isoleucine angiotensin II or enalapril, an angiotensin converting enzyme inhibitor, lowered the blood pressure and enalapril also lowered the angiotensin converting enzyme activity of vascular tissues. The constrictor effect of angiotensin I was greater in isolated arteries from chronically hypertensive rats than in those from age-matched normotensive rats. These results suggest that the vascular renin-angiotensin system plays an important role in the maintenance of two-kidney, one clip hypertension. Elevated vascular angiotensin converting enzyme activity appears to increase local production of angiotensin II, which results in vasoconstriction by acting directly and indirectly through adrenergic nerves on vascular smooth muscle.

Angiotensin II↗
PubMed1986

Trimethadione tolerance test for evaluation of functional reserve of the liver in patients with liver cirrhosis and esophageal varices.

Dimethadione (DMO)/trimethadione (TMO) ratios in serum after oral administration of TMO were investigated in 15 normal subjects and in 20 patients with cirrhosis and esophageal varices. Severe impairment of liver function was associated with a decrease in total cholesterol, total protein and plasma albumin, or an increase in total bilirubin, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, serum gamma-glutamyl transpeptidase and indocyanine green retention rate (ICG R15). Serum concentration ratios of DMO to TMO at 2 or 4 h after oral administration of TMO in patients were significantly decreased by 67 or 66%, respectively, compared to normal subjects. DMO/TMO ratios at 2 or 4 h following oral administration of TMO were well correlated with the liver function parameters (plasma albumin r = 0.758 at 2 h, r = 0.776 at 4 h; total protein r = 0.613 at 2 h, r = 0.619 at 4 h; ICG R15 r = -0.683 at 2 h, r = -0.746 at 4 h, in patients only; cholinesterase r = 0.873 at 2 h, r = 0.908 at 4 h) as well as with pharmacokinetic parameters (total body clearance r = 0.794 at 2 h, r = 0.786 at 4 h) in both the normal subjects and the patients. It suggests that the DMO/TMO ratio obtained in a single blood sample collected after oral administration of TMO might provide a useful measure for function hepatic reserve.

Adult↗
PubMed1986

Hepatic trimethadione-oxidizing capacity remains normal in patients with extrahepatic cholelithiasis.

In the present study, using trimethadione (TMO) as an indicator substrate, we estimated pre- and post-operative differences in hepatic drug-oxidizing capacity in patients with extrahepatic cholelithiasis. Only total and direct bilirubin values were significantly higher in preoperative patients than in the controls. After operative procedures, those parameters did not show significant differences from corresponding control values. The serum dimethadione (DMO)/TMO ratios estimated 4 h after administration of 4 mg/kg of TMO. Neither pre- nor post-operative serum DMO/TMO ratios were significantly different from those in the controls. These results suggest that the hepatic drug-oxidizing capacity in patients with extrahepatic cholelithiasis remains unchanged even though the bilirubin level deviated from normal.

Bilirubin↗
PubMed1986

[A case of CSF (colony-stimulating factor)-producing lung cancer and a review of the literature].

A 36-year-old man with large-cell carcinoma of the lung showed marked leukocytosis of up to 109,300/mm3. As high CSF activity was detected in the pleural effusion and the supernatant of cell cultures originating from the effusion, a diagnosis of CSF-producing lung cancer was made. Twenty-one CSF-producing lung cancers have been reported in Japan. They comprised 13 large-cell carcinomas, six squamous cell carcinomas, one adenocarcinoma and one small cell carcinoma.

Adult↗
PubMed1986

Intracellular action of renin, angiotensin production and release.

The enzyme renin has been purified and characterized by structural analysis. Pure renin protein was used to produce a specific antibody to renin, which was useful in demonstrating the presence of a specific renin in many tissues other than kidney. In these cells angiotensins I and II and angiotensin converting enzyme were found to coexist with renin by immunohistochemical studies and by the direct determination with cultured cells. Studies with these cells indicated the local production of renin, angiotensinogen and angiotensins in these cells. Angiotensin II produced in the cultured cells was secreted to the outside of the cells while more than 95% renin remained within the cells. Secretion of angiotensin II from the angiotensin producing cells was demonstrated with perfused mesenteric artery. The secretion was stimulated by the adrenergic beta-agonist isoproterenol in a dose-dependent manner and specifically inhibited by a beta 2-antagonist. Angiotensin II secreted from the vascular bed by the beta 2-adrenoceptor stimulation acts locally to facilitate norepinephrine release. These studies demonstrate local production and secretion of angiotensin II and define its physiological role.

Angiotensin II↗
PubMed1986

Age-dependent changes in the response of isolated beagle coronary arteries to transmural electrical stimulation and catecholamines.

In helical strips of proximal and distal coronary arteries from beagles of different ages (30 days, 3 months and 1 and 3 years old) precontracted partially with prostaglandin F2 alpha, responses to catecholamines, transmural electrical stimulation, tyramine and acetylcholine were compared. Proximal coronary arteries from infant beagles responded to norepinephrine and epinephrine with contractions, whereas those from adult (1 and 3 years old) beagles responded with dose-related relaxations. Isoproterenol-induced relaxations were in the order of infant less than young less than adult beagle arteries. Norepinephrine produced contractions in the proximal arteries from infant beagles but relaxations in the distal arteries. Relaxations induced by norepinephrine and isoproterenol were in the order of small greater than medium greater than large-size arteries from adult beagles. Transmural stimulation and tyramine produced contractions in the infant and young beagle arteries of proximal portion but only relaxations in the adult beagle arteries. The contractions induced by transmural stimulation and norepinephrine were suppressed by prazosin but not by yohimbine. Acetylcholine produced similar magnitude of relaxations in the arteries from beagles of different ages. It may be concluded that contractions of coronary arteries mediated by alpha-1 adrenoceptors decrease with age, whereas beta receptor-mediated relaxations increase with age. Alpha-1 adrenoceptor functions appear to be in the order of large greater than medium greater than small-size coronary arteries from beagles of different ages, and beta receptor functions to be in the reverse order.

Acetylcholine↗
PubMed1986

Localization of components of the renin-angiotensin system within the kidney.

Evidence accumulates that intrarenal angiotensin II (AngII) plays important roles in the regulation of renal functions. To determine the mechanism and site of the intrarenal formation of AngII, we employed histochemical and cell biological methods. Immunohistochemical studies have revealed the coexistence of renin and AngII in juxtaglomerular (JG) cells, and electron microscopic studies and subcellular organelle fractionation have demonstrated the colocalization of renin and angiotensin in renin granules. The mechanism of this AngII accumulation has been investigated. Immunoreactive angiotensin I (AngI) appeared slowly in JG cells after prolonged administration of angiotensin-converting enzyme (ACE) inhibitors. Cloned and cultured renin-containing cells derived from rat kidney were also found to contain renin, ACE, and AngI and AngII. The subcellular fractionation of renin granules from rat kidney homogenate demonstrated AngI and AngII in the renin granule fractions. These findings suggest the formation of both angiotensins in JG cells. To study the release of AngII, we determined the presence of the angiotensins in renal lymph. Renin was found in renal lymph at a high concentration. Both AngI and AngII were also present in renal lymph in moderate concentrations. It is possible that AngII in the interstitial fluid may play a role in the regulation of renal functions. From these results it has been concluded that AngII is formed in JG cells in the kidney and is secreted with renin into interstitial fluid and plasma, and that AngII formed in the kidney cells may participate in various renal functions.

Angiotensin II↗
PubMed1986

Surgical treatment for carcinoma at the confluence of the major hepatic ducts.

During the period of November 1976 through October 1984, we have treated 46 patients with carcinoma at the confluence of the major hepatic ducts. Curative resection of the tumor (where no carcinoma cells at the margin of the resected portion were found macroscopically and microscopially), was performed upon ten patients, palliative resections were done in 11, palliative resection and intraoperative radiotherapy (IOR) in ten, bile duct drainage and IOR in three, and percutaneous transhepatic cholangiodrainage in 12. Among the ten patients who underwent curative operation, five are living six to 104 months after operation while the remaining five died four to 72 months postoperatively. Of the 11 patients who underwent palliative resection, five are alive two to 22 months after operation and six died between four and 20 months after operation. For the ten patients with carcinoma in the advanced stages, palliative resection with IOR was performed. Eight patients died 20 days to 16 months after operation while two patients are alive 13 and 14 months after the procedure. Of the three patients who underwent drainage of the bile duct and IOR, two died three months after operation and one patient survived 34 months. Twelve patients underwent drainage of the bile duct only and all died after 13 months. To perform a curative operation for carcinoma located at the confluence of major hepatic ducts, it is necessary to resect the right or left lobe, including the caudate lobe, in many instances. For the patients with carcinoma in the advanced stages, the possibility of long term survival period after operation exists through the use of the combined techniques of IOR and palliative resection of the tumor.

Adult↗
PubMed1986

[Clinical investigations on prostatic carcinoma patients who survived for long periods].

A clinical investigation was conducted on 15 prostatic carcinoma patients who survived for more than 3 years (as of October, 1984) since the initial examination. The patient's age at first examination ranged from 56 to 84 years, and survival time was from 3 to 8 years. There was no correlation between age at first examination and survival time. No statistically significant relationship was found between the initial examination stage and survival time. However, the Stage D group showed a wide-ranging survival time from the shortest to the longest survival time. In the relationship between stage and grade, as cited above, group D reflected multiple aspects of prostatic carcinoma in the broad spectrum observed from Grade 1 to Grade 3. The performance status of the 15 prostatic carcinoma patients was either Grade 0 or 1 at the initial examination. The group classified in Grade 0 at the time of the first examination displayed a more favorable performance status than the Grade 1 group now (P less than 0.05). Regarding the stage variation, 1 patient showed improvement, 12 showed none, and 2 reflected advance of the disease. It is important that radical surgery be indicated in any operable case, and in the inoperable cases long-term control therapy is required.

Aged↗
PubMed1986

Consistency of DNA ploidy between primary and recurrent gastric carcinomas.

Eleven patients with gastric carcinoma, who had undergone re-resection of the lesion due to recurrence in the remnant stomach, were the subjects of a cytophotometric DNA analytical study. The objective was to determine whether or not the DNA cytogenic profile of cancer cells would be consistent during the growth of the carcinoma. The DNA distribution patterns were grouped into types I, II, and III, according to the proportion of aneuploid cell population. Ten of 11 had the same DNA distribution patterns in the primary and recurrent lesions, while in the other one patient with type III in the primary lesion, type II was evident at the time of recurrence. The DNA cytogenic profile of cancer cells is thus a valid cell marker of a given tumor and should be applicable for determining the natural history of gastric carcinoma.

Adult↗
PubMed1986

[Cytophotometric DNA analysis of gastric carcinoma--relationship between DNA ploidy and lymph node metastasis].

Two hundred forty-four cases of gastric carcinoma were subjected to cytophotometric DNA analysis. DNA distribution patterns were roughly classified into low and high ploidies. The ratio of high ploidy was 55.7% (44/79) in the positive group of lymph node metastasis, which was significantly higher than 31.5% (52/165) in the negative group (P less than 0.01). The incidence of lymph node metastasis increased rapidly in the high ploidy cases with the progression of carcinoma, while it increased slowly in the low ploidy cases. DNA ploidy was well correlated with lymph node metastasis, and the mode of metastasis seemed to be different between the low and high ploidy groups.

Cytophotometry↗
PubMed1985

Hepatic coma and amino acids in the nerve endings of the central nervous system.

The levels of amino acids in the cerebral cortex and synaptosomes of 6 autopsied patients who had died of chronic liver diseases with portasystemic shunt were examined and compared with those of controls. The level of threonine in the cerebral cortex and synaptosomes of the 6 patients, who had developed hepatic coma before death, was significantly higher than that of 9 patients without hepatic coma. However, the levels of the neurotransmitters, aspartate, glutamate, and glycine, showed no significant difference between the two groups. In animal experiments, threonine uptake into the synaptosomes was enhanced by an increase of threonine concentration in the cerebral cortex, and at the same time ammonia further promoted threonine uptake. The high level of threonine in the synaptosomes was released just like a neurotransmitter on potassium stimulation in the patients with hepatic coma. Since threonine has no post-synaptic action, it is thought that threonine released in this way somehow interferes with brain action. This phenomenon may play an important role in the development of hepatic coma.

Amino Acids↗
PubMed1985

Early gastric carcinoma in Japanese patients under 30 years of age.

The clinicopathological characteristics of early gastric carcinoma (EGC) in 23 Japanese under 30 years of age were reviewed and the findings compared with data on 53 patients over age 70. In the young patients, there was a female preponderance, a macroscopic solitary lesion and the cancer was of the poorly differentiated type without intestinal metaplasia in the surrounding mucosa. In the old patients, there was a male preponderance; about half the number of patients had macroscopically elevated lesions and 10 of the 53 had a multifocal gastric carcinoma. Here, most lesions were well to moderately differentiated types with intestinal metaplasia in the surrounding area. Growth patterns of EGC in the young patients were analysed. Curative operations with dissection of regional lymph nodes were done in all the young patients. Metastases to the regional lymph nodes were present in only 2 of 23. Twenty of twenty-three followed for 5 years or longer are well.

Adenocarcinoma↗