Biomedical subjects

H Yoshimura

Publications and source records attributed to H Yoshimura.

At least 307 records · Page 17Linked to original sources

PubMed1991

[Effect of cigarette smoking and/or N-bis(2-hydroxypropyl)nitrosamine (DHPN) on the development of lung and pleural tumors in rats induced by administration of asbestos].

Occupationally induced lung cancer and mesothelioma have long been attributed to asbestos and moreover, several epidemiological studies have indicated a co-carcinogenic effect of cigarette smoking on the incidence of lung cancer in asbestos workers. The aim of the present study was to investigate the co-carcinogenic effects of asbestos and other carcinogens with emphasis placed on determining the effects of cigarette smoking on the incidence of asbestos induced carcinomas. Doses of 15 mg of chrysotile asbestos were administered intratracheally to Wistar rats alone and in conjunction with N-bis(hydroxypropyl)nitrosamine (DHPN) and/or cigarette smoking. DHPN at dose of 1 g/kg/B.W. was injected three times intraperitoneally, and the subject animals were exposed to smoke from 10 cigarettes per day, six days a week, for their entire life span. As a result, lung carcinomas were induced in one out of the 31 rats receiving only asbestos. Lung tumors were induced at a much higher incidence in the groups receiving DHPN alone and in conjunction with asbestos: of the 37 rats treated with DHPN alone 19 (51.4%) developed lung tumors, whereas those receiving asbestos as well showed an incidence of 68.4% (23/38) of carcinomas. The development of lung carcinomas (including adenocarcinomas, epidermoid carcinomas, anaplastic carcinomas, and combined carcinomas) was seen in 8 (21.6%) out of the 37 rats receiving DHPN alone and in 23 (60.5%) out of the 38 rats receiving asbestos as well. The incidence of lung carcinoma was significantly increased in combined treatment with asbestos than DHPN alone. In the group receiving asbestos in combination with cigarette smoke, 4 (13.8%) out of the 29 rats developed lung carcinomas, but these carcinomas were more common than in the group receiving only asbestos. Moreover, in the group administered asbestos, DHPN and smoking combined, lung tumors developed in 18 (62.1%) out of the 29, 15 (51.7%) of which proved to be malignant. Mesothelioma (pleura) was induced in three groups in the following combinations: DHPN plus asbestos, 8/38 (21.1%); smoking plus asbestos, 2/29 (6.9%); and smoking, DHPN and asbestos, 4/29 (13.8%). These tumors were extensively located, that is, on the parietal pleura, visceral pleura, epicardium and diaphragm surface. However, mesothelioma was not induced by asbestos alone nor by DHPN alone. Carcinogenicity of asbestos for pleural tumors was significantly promoted by combined treatment with DHPN to an extent greater than DHPN alone. It should be noted that asbestos plus smoking resulted in a higher incidence of mesothelioma than asbestos alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗

PubMed1991

A novel metabolite of strychnine, 22-hydroxystrychnine.

1. An unknown metabolite of strychnine termed M-5 was isolated, from an incubation mixture using guinea pig liver microsomes, by repeated preparative t.l.c. 2. The structure of M-5 was shown to be 22-hydroxystrychnine by mass, n.m.r. and i.r. spectrometry. 3. 22-Hydroxystrychnine is a stable enol, a unique metabolite possessing a hydroxyl group on the double bond of the alicylic moiety.

Animals↗

PubMed1991

Metabolism in vivo of the tropane alkaloid, scopolamine, in several mammalian species.

1. In vivo metabolism of scopolamine was studied in rats, mice, guinea pigs and rabbits. The structures of eight urinary metabolites including unchanged drug were elucidated by mass and nuclear magnetic resonance spectrometry. Determination of these metabolites was achieved by a g.l.c. method using a semi-capillary column. 2. The major metabolites in rats were the three phenolic metabolites, p-hydroxy-, m-hydroxy- and p-hydroxy-m-methoxy-scopolamine. 3. Significant intra-species difference of the metabolism was observed in rabbits. Tropic acid was the major metabolite in two rabbits out of three, while the other rabbit excreted mainly unchanged scopolamine, accompanied by five metabolites. Tropic acid was also the major metabolite in guinea pigs, but was of minor importance in mice. 4. The dehydrated metabolites, aposcopolamine and aponorscopolamine, were abundantly excreted in guinea pigs, moderately in mice, and least in rabbits and rats. 5. Excretion of glucuronide conjugates of scopolamine and norscopolamine were high in mice compared with other species. On the other hand, phenolic metabolites in rat urine; and tropic acid in rabbit and guinea pig urine, were excreted as the free forms. 6. These results indicate that scopolamine metabolism is highly species-specific.

Animals↗

PubMed1991

[Ultrastructural study of the blood-testis barrier in rat by the lanthanum method].

Ultrastructural changes of the testes in 35-week-old WBN/Kob rats were investigated using the lanthanum-tracer method. Tissues were cut and fixed with a solution containing 1% lanthanum and 2% glutaraldehyde in a 0.1 M sodium cacodylate buffer at pH 7.8 and with a solution of 2% osmium and 1% lanthanum in a 0.1 M sodium cacodylate buffer. Ultrathin sections of epoxy resin-embedded specimens were stained with uranyl acetate and lead citrate and observed into a JEM-100CXS JEOL transmission electron microscope. The remnants of each testis were fixed in Bouin's fixative, and observed light-microscopically, where almost all seminiferous tubules in all of the six testes were found to be severely atrophied. Electron microscopically, lanthanum pigments were limited in the Sertoli cell tight junctions of the seminiferous tubules even in the severely atrophied tubules. In conclusion, it is unlikely that the testicular atrophy in WBN/Kob rats is attributable to dysfunction of the blood-testis barrier.

Animals↗

PubMed1991

[Pharmacokinetic study of adriamycin in the emulsion mixed with lipiodol-difference resulting from composition and methods of preparation, and behavior after mesenteric arterial injection in rat].

We experimentally investigated the pharmacokinetics of adriamycin (ADM) in a similar of transcatheter arterial chemoembolization therapy (TAE) of hepatocellular carcinoma using emulsion of lipiodol (Lp) mixed with ADM followed by gelatin sponge, and the difference resulting from composition and method of preparation of the emulsion as well as behavior after mesenteric arterial injection in rat. In in vitro study, the emulsion with iopamidol (iopamiron 300 : IP) was more stable than with amidotrizoic acid (60% Urografin : UG). The highest stability was found in the mixing ratio of Lp. IP and distilled water at 1 : 0.42 : 0.08. Frequent pumping also made the emulsion more stable. But in optimally composed emulsion, pumping 20 or 50 times made no difference in the stability during 30 min. which may be longer than the time from preparation to injection time of the emulsion in clinical application. After injection of the emulsion into the mesenteric artery which may simulate injection into the hepatic artery in hepatocellular carcinoma, the arterial blood flow was suspended. In the peripheral arteries the emulsion separated into two phases of Lp and ADM solution, forming striped pattern, and Lp embolization of the peripheral artery persisted for over 45 min. while ADM extravasated. These findings suggest that after Lp-TAE, Lp maintains an embolizing effect while ADM penetrates into the surrounding tumor tissue, and that this is an underlying mechanism for the anti-cancer effect of Lp-TAE.

Animals↗

PubMed1991

Image analysis by electron microscopy of two-dimensional crystals developed on a mercury surface of chaperonin from Thermus thermophilus.

Two-dimensional crystals of functional chaperonin molecules, which are protein complexes of cpn60 and cpn10, isolated from Thermus thermophilus were prepared on a mercury surface under oxygen atmosphere and were observed by electron microscope after transferring them to carbon coated specimen grids. The crystals showed the hexagonal lattice with unit cell dimensions of a = b = 12.4 nm and gamma = 120 degrees. The averaged image at a 3 nm resolution of the chaperonin has a doughnut-like shape which has seven peripheral masses and a central cavity. Preincubation of the chaperonin with MgATP changed the mobility in non-denaturating PAGE but did not cause distinguishable change of shape. The location of cpn10 in the chaperonin molecule is discussed.

Bacterial Proteins↗

PubMed1991

[Coronary collateral vessels during the early period of acute myocardial infarction: their development].

The aim of this study was to investigate the incidence and development of coronary collateral circulations in patients with acute myocardial infarction (AMI). We categorized 165 patients with persistent 100% occlusion of the infarct-related artery into 6 groups according to the time from the onset of AMI to angiography. Group I consisted of 55 patients evaluated within 6 hours after the onset of AMI; Group II, 28 patients, between 6 and 12 hours after the onset; Group III, 12 patients, between 12 and 24 hours after the onset; Group IV, 11 patients, between 2 and 13 days after infarction; Group V, 46 patients, between 14 and 44 days after infarction; and Group VI, 13 patients, more than 45 days after infarction. Collateral vessels were applied a numerical score between 0 and 3 according to the degree of opacification of the native vessel distal to the occlusion. In 58%, 79%, 67%, 73%, 89%, and 92%, patients of Groups I to VI had evidence of collateral vessels, respectively. Well-developed collaterals were observed in 24% of Group I compared with 50%, 58%, 55%, 73% and 69% of patients in Groups II to VI, respectively. The mean coronary collateral scores were 0.9 +/- 0.1, 1.4 +/- 0.2, 1.4 +/- 0.3, 1.6 +/- 0.4, 2.0 +/- 0.2 and 2.2 +/- 0.3 for Groups I to VI, respectively. Patients with preinfarction angina had more well-developed collateral circulations than did patients without it, however, there was no significant correlation between the duration of previous angina and extent of coronary collaterals.

Adult↗

PubMed1991

[Development of slow releasing anticancer drug based with absorbable biomaterial chitin].

To have a comparatively more slowly releasing anticancer drug with effectiveness, Plachitin was prepared by chemical combination of CDDP and chitin (poly-N-acetyl-D-glucosamine). Chitin is absorbed by the living body over several months. To investigate the slow releasing property, it was implanted in thigh muscle of mice and rabbit. Pt level in different organs and in urine was measured at regular intervals. Pt level in implanted muscles was higher in comparison to low serum level in mice. It was released slowly over 1 to 2 months in mice, whereas in rabbit it took about three weeks. Pt releasing period of the Plachitin was different according to the adopted method of implantation. Anticancer effect of Plachitin was investigated by injecting 180 sarcoma cells in mouse peritoneal cavity and subsequent implantation of Plachitin. In control groups chitin was used instead of Plachitin. The survival rate of mice in the Plachitin group after 14 days was higher than in the chitin group, and the anticancer effect of the Plachitin was confirmed.

Absorption↗

PubMed1991

[Toxicological assessment of 2,5,2',5'-tetrachlorobiphenyl and its major metabolite, 3-hydroxy-2,5,2',5'-tetrachlorobiphenyl in rats].

We observed previously that polychlorinated biphenyl (PCB) could be classified to two groups, 3-methylcholanthrene (MC)-type and phenobarbital (PB)-type, in term of inducibility of the hepatic enzymes. MC-type PCBs such as 3,4,3',4'-tetrachlorobiphenyl (TCB), 3,4,5,3',4'-pentachlorobiphenyl (PenCB) and 3,4,5,3',4',5'-hexachlorobiphenyl (HexCB) exhibited high acute toxicity in parallel with their induction ability of microsomal benzo[a]pyrene 3-hydroxylase and cytosolic DT-diaphorase. On the contrary, PB-type PCBs such as 2,5,2',5'-TCB and 2,4,5,2',4',5'-HexCB which induce microsomal benzphetamine N-demethylase and NADPH-cytochrome P-450 reductase activities showed virtually no or very low toxicity. In the present study, we examined effects of 2,5,2',5'-TCB and its major metabolite 3-hydroxy-2,5,2',5'-TCB on body weight gain, organ weights and activities of hepatic enzymes in rats and assessed acute toxicity of these compounds. As the results, in both 2,5,2',5'-TCB and 3-hydroxy-2,5,2',5'-TCB groups, the body weights were increased during the experiment, but the rate of growth was significantly suppressed after 3 days. Significant hypertrophy of the liver and decrease of total liver lipid content were observed in 2,5,2',5'-TCB group, but the atrophy of spleen and thymus was not affected in both groups. On the other hand, in 2,5,2',5'-TCB group, benzo[a]pyrene 3-hydroxylase and benzphetamine N-demethylase activities were increased to 2. 4-fold and 1.5-fold, respectively, but were not increased in 3-hydroxy-2,5,2',5'-TCB group. After injection of 2,5,2',5'-TCB, 45% of the dose was excreted as 3-hydroxy-2,5,2',5'-TCB in feces for 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

[Acute toxicity, inductive effects of liver enzymes and distribution in the liver of 1,2,3,7,8-pentachlorodibenzo-p-dioxin in rats].

Acute toxicity, inductive effects of liver enzymes and liver persistency of 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PenCDD) were compared with those of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) using male Wistar rats. 1,2,3,7,8-PenCDD treatment at a dose of 0.1 mumol/kg resulted in significant depression of growth of rats from a day to 28 days after treatment. However, the effect was relatively less than that of 2,3,7,8-TCDD. On 5 days, similarly to 2,3,7,8-TCDD-treated group, liver hypertrophy and thymic atrophy were observed in 1,2,3,7,8-PenCDD-treated groups. In addition, 1,2,3,7,8-PenCDD showed potent 3-methylcholanthrene-type inducing ability. For example, the activities of benzo(a)pyrene 3-hydroxylase and DT-diaphorase were 25-fold and 10-fold of control, respectively. On 30 days, about 50% of the inductive effects on 5 days were maintained in both 1,2,3,7,8-PenCDD- and 2,3,7,8-TCDD-treated groups. Amount of 1,2,3,7,8-PenCDD distributed to the liver on 5 days was about 80-90% of dose and was about 1.5 times greater than that of 2,3,7,8-TCDD. About 50% of dose of 1,2,3,7,8-PenCDD remained even on 30 days after treatment. From these results, it is suggested that 1,2,3,7,8-PenCDD possessing the potent acute toxicity comparable to 2,3,7,8-TCDD and higher persistency in the liver might be more important than 2,3,7,8-TCDD in terms of the chronic toxicity.

Animals↗

PubMed1991

[Studies on distribution and excretion of squalane in dogs administered for 2 weeks].

In the previous papers, we demonstrated, by using rats, that squalane (2,6,10,15,19, 23-hexamethyltetracosane) could stimulate the fecal excretion of 2,3,4,7,8-pentachlorodibenzofuran, the most important etiologic agent of Yusho, which was accumulated in the body of rat. We also reported that, in rats and dogs, squalane did not show any appreciable toxic signs during 3-month treatment, though a part of squalane was absorbed from gastrointestinal tract of dogs. In the present paper, we have investigated the elimination of absorbed squalane in beagle dogs. During the treatment with squalane orally at a dose of 1200 mg/kg/day for 14 days, the fecal excretion of squalane per day was 65-90% of the daily dose. After the treatment (on the day 14), squalane levels in blood and hair were about 30 ppm and 14640 ppm, respectively. On the day 56 after the first dosing, squalane was not detected in blood. On the day 70, squalane level in hair was reduced to about 1% of that on the day 14. Squalane levels in skin, liver, adipose tissue and small intestine on the day 70 were also reduced compared with that on the day 42. Moreover, small amount of squalane was still excreted into feces from the day 15 to the day 70. These results suggested that absorbed squalane was gradually excreted through feces and skin in dogs.

Administration, Oral↗

PubMed1991

[Chronic hemorrhagic empyema developed in thirty three years after the right pneumonectomy--a case report].

A 55-year-old man was admitted because of exertional dyspnea. He had the right pneumonectomy thirty three years ago. Chest X-ray showed the mediastinal shift to the left. And chest CT scan showed right intrathoracic mass. The bloody pleural effusion was aspirated (Hb 9.4 g/dl) and its examination revealed Staphylococcus epidermidis. We resected the empyema cavity. During the operation, massive bleeding was experienced (total 23200 ml). Pathologically, micro blood vessels were marked in the organized hematomas and the pleura. Chronic hemorrhagic empyema is a specific type of chronic empyemas and it is dangerous to remove of the hematomas because of massive bleeding.

Chronic Disease↗

PubMed1991

[Pleuropneumonectomy with combined resection of diaphragma, superior vena cava, and pericardium, for invasive thymoma with pleural dissemination].

A 63-year-old female was admitted to our hospital with chief complaint of exertional dyspnea. Right massive pleural effusion was found. After chest drainage was performed, chest CT scan and MRI showed several masses in the anterior mediastinum and on the diaphragma. Mesothelioma was suspected for needle biopsy. Pleuropneumonectomy with combined resection of diaphragma, superior vena cava and pericardium was performed. Histologically, the Tumor was mixed thymoma. She is well and alive for three years after operation. Pleuropneumonectomy may be a choice of effective treatments for invasive thymoma with pleural dissemination.

Diaphragm↗

PubMed1991

Serosal invasion as the single prognostic indicator in stage IIIA (T3N1M0) gastric cancer.

Prognostic factors of gastric cancer with positive serosal invasion and regional lymph node metastasis were evaluated by multivariate analysis. Sixty-seven patients with the T3N1M0 subgroup of stage IIIA disease were evaluated, in which 34.9 +/- 13.4 nodes were dissected in extended lymph node dissection, and 6.5 +/- 6.2 were metastatic. Routine postoperative systemic chemotherapy with mitomycin C and N1-(2'-tetrahydrofuryl)-5-fluorouracil was administered. With this approach, the 5-year survival rate of stage IIIA disease was 47.6%. By Cox proportional hazards model, diameter of serosal invasion was the only significant determinant of prognosis in the T3N1M0 subgroup. The predicted 5-year survival rate for 24 patients with serosal invasion less than 3.0 cm in diameter was 59.5%, compared with 11.5% for 38 patients with invasion of 3.0 cm or larger in diameter. The number of metastatic nodes and the type of operation (total gastrectomy or less than total gastrectomy) did not affect the prognosis. When gastric cancer has both positive serosal invasion and metastatic regional lymph nodes, the diameter of serosal invasion is the more important factor for predicting prognosis.

Adenocarcinoma↗

PubMed1991

[The effect of prostaglandin I2 on the postischemic recovery of the transplanted heart under deep hypothermia].

The effect of prostaglandin I2 (PGI2) on the postischemic recovery of the heart orthotopically transplanted under deep hypothermia was evaluated using puppies. Twenty-four pairs of dogs were divided into 4 groups according to the usage of PGI2 and preservation of the donor heart (in Euro-Collins' solution at 4 degrees C for 4 hours), namely Group I (non PGI2, no preservation), Group II (PGI2-treated, no preservation), Group III (non PGI2, 4 hours preservation), Group IV (PGI2-treated, 4 hours preservation). PGI2 was added into the donor's cardioplegic solution (500 ng/ml) and also was given intravenously to the recipient during cooling and rewarming periods (1 microgram/kg/min), and left ventricular pressure, max dp/dt, cardiac output were continuously monitored, and postmortem studies on myocardium were performed. Results were as follows: PGI2 yielded significantly better recovery of cardiac output and left ventricular pressure after transplanted of the heart, [Group I vs Group II (p less than 0.05), Group III vs Group IV (p less than 0.01)]. This effect was especially remarkable in the preserved heart groups. Microscopically, the contraction band formation in the myocardium was more prominent in Group III than in Group IV. It is concluded that PGI2 is of great use for the postischemic recovery of the transplanted heart not only by ameliorating the myocardial ischemic recovery of the transplanted heart, but also by reducing the afterload of the recipient during the recovery period from deep hypothermia.

Animals↗

PubMed1991

[Legionnaires' disease with mediastinal lymph nodes swelling, diagnosed by open lung biopsy--a case report].

Legionnaires' disease in a 37-year-old male who had had silicosis was reported. He was admitted because of dyspnea. The chest X-ray film and CT scan showed infiltrative shadow and swelling of mediastinal lymph nodes. Open lung biopsy was done and Legionella pneumohila was detected. REP and EM were started and infiltrative shadow of X-ray was disappeared. Pleuro-pneumonectomy and thoracoplasty were performed because of hemoptysis and postoperative empyema. The patient is now well.

Adult↗

PubMed1991

[Mechanism of the B-B' step formation in M-mode echocardiography].

This study analyzed the mechanism involved in the B-B' step formation of the mitral valve movement using pulsed Doppler and color Doppler echocardiography. We examined 24 patients with first degree atrioventricular block (AVB), 26 with old myocardial infarction (OMI), and 34 with a DDD-pacemaker (PM) (16 with complete AV block and 18 with sick sinus syndrome). In 19 of 24 AVB patients, the B-B' step was associated with diastolic mitral regurgitation (DMR). There was a significant positive correlation between the magnitude of the PQ interval and the B-B' step duration (r = 0.94, p less than 0.001). Intravenous administration of 1 mg of atropine shortened the B-B' step duration from 0.15 +/- 0.06 (SD) to 0.05 +/- 0.07 sec (p less than 0.001). Although changes in the PQ interval were well correlated with changes in the B-B' step duration, the P-B-B' step, or PC interval, did not change significantly. In 12 of the 26 OMI patients, the B-B' step and DMR were both observed. The QC intervals of these patients were longer than those of OMI patients without the B-B' step (0.088 +/- 0.03 vs. 0.066 +/- 0.021 sec, p less than 0.05). The P-B-B' step interval was shorter in the OMI patients than in the AVB patients (0.190 +/- 0.029 vs 0.232 +/- 0.033 sec, p less than 0.01). In 28 of 34 patients implanted with a DDD-pacemaker, the B-B' step and DMR were induced by prolonging the AV delay.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗

PubMed1991

[A case of pneumothorax which was operated with the axillary longitudinal small incision].

A pneumothorax usually occurs in young men. From the cosmetic point of view, the size of the skin incision should be considered to be minimal if surgery is applied for young pneumothorax patients. We reported a case of pneumothorax which was operated with a small longitudinal axillary skin incision, the size of which was 3.5 cm long. The patient was a 18-year-old high school student. He was admitted to our hospital with the diagnosis of spontaneous pneumothorax. His chest X-ray showed a moderate collapse of his left lung and bullae in his left apex. Tube drainage was performed and the collapsed lung re-expanded completely. Chest CT scan demonstrated that he had bullae in the apex of his left lung. No other lesions were found in the other part of both lungs. Surgery was indicated socially. Bullectomy was successfully performed with a small (3.5 cm) longitudinal axillary skin incision. We recommend this skin incision for young patients with pneumothorax if the chest CT scan confirms that the bullae or blebs are localized to the apex of superior segment of the lower lobe.

Adolescent↗