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Biomedical subjects

H Yoshimura

Publications and source records attributed to H Yoshimura.

At least 361 records · Page 20Linked to original sources
PubMed1990

[Carcinogenicity of anticancer agents].

Chemotherapeutic treatment for cancer has been successful in prolonging survival but it has also been demonstrated that survivors of cancer patients who had received chemotherapy with alkylating agents have an increased risk of second malignancies, mostly acute non-lymphatic leukemia. The purpose of this paper is to show practical problems pertaining to the development and clinical use of anticancer agents in terms of prevention of second cancers.

Alkylating Agents↗
PubMed1990

[Evaluation of combined resection of aortic wall in lung cancer invaded aorta].

Left pneumonectomy with combined resection of aortic wall was performed for three patients with lung cancer invaded aorta. In clinical and pathological examination, the following results were obtained. 1: In all three cases, metastasized subaortic lymphnodes invaded to medial wall of the descending aorta. 2: Microscopically, invasion of aortic wall was limited to the adventitia adjacent to the muscle layer. We think that the resection of whole layer of the aortic wall was preferable. 3: The resections of aortic wall were performed under partial clamp of aorta in one case, and under total clamp with the use of cardiopulmonary bypass in two cases. If the area of invasion is wide, total clamp was recommended. 4: Two patients died of recurrent disease 56 months and 20 months after surgery. In the other one, postoperative empyema was occurred. He died of bleeding from the suture line of Dacron patch to the aortic wall three months postoperatively. Covering of the bronchial stump and the patch of the aorta should be considered to prevent postoperative empyema.

Adenocarcinoma↗
PubMed1990

[Evaluation of MRI for the staging of esophageal cancer].

The usefulness of MRI (magnetic resonance imaging) was evaluated in the diagnosis of the mediastinal invasion of esophageal cancer. MR examination was performed in 30 subjects without esophageal diseases and 23 patients with esophageal cancer. Normal esophagi and cancers were well visualized using T1-weighted image. In the axial section, every normal esophagus was contact to the aorta in the angle of less than 30 degree of the aortic circle. When the contact angle was less than 30 degrees, the stage of the cancer was below a1. When the angle was 30 degrees or greater, the stages were ranged from a0 to a3. In the oblique section orthogonal to the contact plain between the cancer and the aorta, the depth of the aortic invasion could be estimated. The sagittal scan was also helpful in the diagnosis of the invasion to trachea, left main bronchus and left atrium.

Esophageal Neoplasms↗
PubMed1990

[Clinicopathological study of endometrial-type adenocarcinoma of uterus].

Seventy-one resected cases of endometrial-type adenocarcinoma of uterus were clinicopathologically investigated. As to the gross findings, the incidence of localized type and diffuse type was 47.9% and 52.1%, while that of extroversive type and introversive type was 59.1% and 40.9%, respectively. The incidence of the lesions less than 3 cm in diameter was 36.7% and that beyond 5 cm was 28.1%. The majority (88.7%) of the endometrial-type adenocarcinoma were histologically well-differentiated. Concerning depth of invasion, the incidence of the cases of intramucosal invasion, invasion within 1/3 of muscle layer, invasion between 1/3 and 2/3 of muscle layer, and invasion beyond 2/3 of muscle layer was 19.7%, 46.5%, 16.9%, and 16.9%, respectively. Lymphatic and venous invasion were more frequently found in diffuse, introversive, moderately-differentiated, and deep invasive types than the other types. Lymph nodal metastasis was found in 9.8% of all cases (16.2% in diffuse type, 20.8% in introversive type, 33.3% in moderately-differentiated type and 41.7% in the cases beyond 2/3 of muscle layer).

Adenocarcinoma↗
PubMed1990

[Evaluation of a biliary endoprosthesis using expandable metallic stents].

A biliary endoprosthesis constructed of Gianturco self-expanding metallic stents was placed in twenty-nine patients with obstructive jaundice, 27 malignant and 2 benign. All endoprostheses were placed successfully. External drainage catheters were removed in twenty-seven patients. At the follow-up, ranging from two to 59 weeks, the 30 day mortality rate was 7.4%. Twenty-eight patients had obvious clinical improvement with relief of jaundice. Seven patients experienced recurrent jaundice. In two of these patients, the obstruction was relieved by additional metallic stents. The expandable metallic biliary endoprosthesis is suggested as an effective treatment for biliary obstruction.

Adult↗
PubMed1989

A rabbit liver constitutive form of cytochrome P450 responsible for amphetamine deamination.

A cytochrome P450 isozyme responsible for amphetamine deamination was purified from hepatic microsomes of untreated rabbits. The purification procedures consisted of a set of column chromatographies with omega-aminooctyl-Sepharose 4B, DEAE-cellulose, CM-Sephadex C-50, and hydroxyapatite. The deamination activity was determined by measuring the formation of phenylacetone after derivatization to the p-nitrobenzyloxim by HPLC. This isozyme, which was designated P450APD, showed a monomeric molecular weight of 51,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and exhibited an absorption maximum of reduced CO complex at 451 nm. On the basis of the specificity toward testosterone metabolism and the N-terminal amino acid sequence, P450APD was attributed to a member of P450 class IIC subfamily, which is identical or closely related to LM3b (D. R. Koop and M. J. Coon (1979) Biochem, Biophys, Res. Commun. 91, 1075-1081), form 3b (E. F. Johnson (1980) J. Biol. Chem. 255, 304-309), and other similar preparations. Antibody against the P450APD inhibited about 80% of the amphetamine deamination activity in rabbit hepatic microsomes as well as in the reconstitution system of this P450. The present results support that P450APD is the major P450 isozyme responsible for amphetamine deamination in rabbit liver.

Amphetamine↗
PubMed1989

Plasma concentration and placental transfer of bromofenofos in rats.

Bromofenofos (BF) was administered by gavage once to non-pregnant and pregnant rats at 50 mg/kg and the plasma concentration-time curves of BF and its metabolite dephosphate bromofenofos (DBF) were determined by high-performance liquid chromatography. DBF reached a peak at 9 h, with 113.4 +/- 5.2 micrograms/ml, followed by a subsequent decline with a plasma half-life of approximately 24 h, but BF was not detected at any time. Next, the concentration of DBF in the conceptus was determined in rats administered BF (50 mg/kg) on day 10 of pregnancy. The concentration in the conceptus did not exceed 30% of that in the maternal plasma at all times, with a maximum of 32.3 +/- 3.3 micrograms/g at 12 h. No BF was detected in maternal plasma. Third, BF (50 mg/kg) was administered to rats on day 15 of pregnancy to determine whether DBF could cross the placenta. The concentration of DBF in the placenta was nearly half that in the maternal plasma at all times. The fetal concentration was approximately 20% of the concentration in the maternal plasma by 24 h. DBF was detected in the amniotic fluid at all times, but the concentration was low, with a maximum of 11.1 +/- 1.4 micrograms/ml at 12 h.

Amniotic Fluid↗
PubMed1989

[An experimental and clinical study of thin-slice high-resolution CT for lung detail].

The clinical usefulness of thin-slice high-resolution CT in the diagnosis of the chest was assessed by (1) experiments using a phantom and an inflated fixed lung (Heitzman's method), (2) evaluation of the CT delineativity of the bronchi and major fissure and (3) clinical examination of patients with diffuse pulmonary diseases. 1) In a phantom experiment using catheters, 10 mm-thick slice scan showed the 6 catheters as a single faint line. By 1.5 mm-thick slice scan, the catheters were defined as 6 separate lines. The profile images suggested that 1.5 mm-thick slice scan enables delineation of more minute details of structures. 2) In an experiment using an inflated fixed lung, 1.5 mm-thick slice scan produced more informative images that resembled macroscopic or soft X-ray images. 3) By 1.5 mm-thick slice scan, the subsegmental bronchi of both the right and left lobes were identified in most cases, while identification was possible in only half the cases by 10 mm-thick slice scan. 4) By 10 mm-thick slice scan, the sub-subsegmental bronchi were not identified in most cases. However, identification was possible in approximately half the cases by 1.5 mm-thick slice scan. 5) By 1.5 mm-thick slice scan, the major fissure was delineated as a linear shadow in most cases. It was hardly recognizable by 10 mm-thick slice scan. 6) In diffuse pulmonary diseases, 1.5 mm-thick slice scan allowed more minute visualization of the patho-morphological changes compared to 10 mm-thick slice scan. 7) Thin-slice high-resolution CT is thus expected to contribute to pathological analysis and more accurate diagnosis of pulmonary diseases.

Humans↗
PubMed1989

Acute and chronic effects of psychotropic drugs on maternal aggression in mice.

The present study investigated the acute and chronic effects of psychotropic drugs on maternal aggression in mice. All female mice had been singly housed since the end of the 4-day mating period. Behavioral testing for acute drug effects was carried out on postpartum days 5 and 7. Chronic drug treatment was started immediately after removal of the partner male, and was terminated on the 3rd postpartum day; behavioral testing was done on the 5th postpartum day. Acute administration of chlordiazepoxide (CDP; 5, 10 and 15 mg/kg, IP) showed a biphasic effect on maternal aggression; 10 mg/kg CDP significantly increased the frequency of bites, while 15 mg/kg CDP significantly decreased it. Imipramine (IMP; 5, 10 and 15 mg/kg, IP) decreased the frequency of bites in a dose-dependent manner. Haloperidol (HAL; 0.1, 0.2 and 0.4 mg/kg, IP) also decreased the frequency of bites dose dependently, but 0.2 and 0.4 mg/kg HAL decreased both the frequency and duration of locomotion. Chronic treatment with either CDP (5 and 10 mg/kg, IP) or HAL (0.1 and 0.2 mg/kg, IP) failed to alter the frequency of bites. This evidence indicates that the antidepressant imipramine has a specific action in alleviating postpartum female aggression, and suggests that female aggression in mice is a useful tool for differentiating the actions of psychotropic drugs.

Aggression↗
PubMed1989

Alteration in hypnotic effect of pentobarbital following repeated agonistic confrontations in mice.

We investigated how repeated agonistic confrontations affect the hypnotic effect of pentobarbital (PB) in male mice, using a resident-intruder paradigm. PB concentrations in the cortex, midbrain and brainstem were determined. Agonistic confrontations were terminated after 10 or 20 attack bites, and were repeated for 5 consecutive days. Immediately after the last encounter, PB (55 mg/kg, IP) was administered to both resident and intruder mice. Compared to the control group, intruders exposed to 20 daily attack bites showed a significant prolongation of the latency to sleep and a shortening of the duration of sleeping time. At the stage of induction, no significant difference in brain PB levels was found between the "defeated" and control intruders. At the stage of recovery, however, the "defeated" intruders showed a significantly low level of PB in all brain areas. In contrast, attacking resident mice did not show any significant changes in either the hypnotic effect or regional brain concentration of PB. Because pretreatment with naloxone prior to daily agonistic confrontation antagonized the alteration in PB-induced hypnosis, it seems that endogenous opioid mechanisms may participate in this phenomenon. The present study indicates that susceptibility to a hypnotic drug can be altered by chronic social conflict experience.

Aggression↗
PubMed1989

Transcatheter arterial embolization using iodized oil (lipiodol) mixed with an anticancer drug for the treatment of hepatocellular carcinoma.

The therapeutic results of Lp-TAE (transcatheter arterial embolization with Gelfoam particles preceded by the infusion of a mixture of lipiodol and an anticancer drug via the proper hepatic artery) were evaluated in hepatocellular carcinomas (523 non-resected and 24 resected cases). Excellent therapeutic effects were confirmed not only for the main tumor but also for the daughter nodules by a histological examination of the liver tissues resected after Lp-TAE. The cumulative 1-year, 2-year and 3-year survival rates in the 523 non-resected cases were 60.4%, 42.9% and 28.0% respectively. These survival rates were all higher than those achieved by Gelfoam TAE. The above results suggest the usefulness of Lp-TAE in the treatment of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1989

Preventive and curative effects of prostaglandins on stress ulcer in rats. Application of endoscopic observation.

The present study investigated the preventive and curative effects of prostaglandins (PGs) on gastric ulcer in rats induced by physical or psychological stresses; some rats were electrically shocked, while others were exposed to affective stimuli arising from the shocked animals. The synthetic PGs dimethyl-PGE2 and rioprostil were administered orally, and their preventive effect on gastric ulceration was evaluated by determining the incidence and the ulcer index of lesions. The curative effect of drugs on ulcer healing was evaluated by determining a time-dependent change in the mucosal surface of the stomach with an endoscopic technique. Oral administration of dimethyl-PGE2 or rioprostil (25 and 50 micrograms/kg) prevented gastric ulceration significantly. Oral administration of these drugs (50 micrograms/kg, twice per day) significantly promoted the healing process of lesions 24 and 36 hr after termination of stress loading. The present results give direct evidence of the curative effect of PGs on stress ulcers and suggest that application of the endoscopic technique to the pathology of the rat's stomach may be a substantial aid in the preclinical evaluation of antiulcer drugs.

16,16-Dimethylprostaglandin E2↗
PubMed1989

Hexagonal structure of two-dimensional crystals of the alpha 3 beta 3 complex thermophilic ATP synthase.

The highly dissociable alpha 3 beta 3 subunit complex (Mr = 319,582) of thermophilic ATP synthase was crystallized on a mercury surface under oxygen. The two-dimensional crystal was compared with that of TF1 (Mr = 385,351, alpha 3 beta 3 gamma delta epsilon subunit complex) by means of computer image processing. The crystals showed the same hexagonal lattice (a = b = 10 nm), despite the difference in their molecular weights. The color images of the two protein molecules were also hexagonal. However, there was an open hole in the image of the alpha 3 beta 3 complex, where small subunits (gamma, delta, and epsilon) of TF1 may have been located. The structure of this heterohexamer is consistent with that deduced from other physical parameters.

Crystallization↗
PubMed1989

Right upper lobe versus right middle lobe: differentiation with thin-section, high-resolution CT.

A new method was developed to differentiate the upper lobe from the middle lobe of the right lung with thin-section, high-resolution computed tomography. In the upper lobe, a medial subsegmental bronchus of an anterior segmental bronchus is always located lateral to the corresponding artery. In the middle lobe, a medial subsegmental bronchus of a lateral segmental bronchus and a superior and inferior subsegmental bronchus of a medial segmental bronchus are always located medial to the corresponding artery. In other words, the anatomic relationship between the subsegmental bronchi and the corresponding pulmonary arteries in the upper lobe is opposite to that in the middle lobe. One hundred seventeen cases, including 54 cases of lobar volume loss, were reviewed with this method, and in each case it was possible to differentiate the upper lobe from the middle lobe without the contiguous section analysis.

Adult↗
PubMed1989

Mechanism of biological formation of cannabielsoin from cannabidiol in the guinea-pig, mouse, rat and rabbit.

Biological formation of cannabielsoin (CBE) from cannabidiol (CBD) was studied in the guinea pig, mouse, rat and rabbit in vitro. Emphasis was placed on the elucidation of this formation mechanism. The enzyme activity of CBE formation was localized in hepatic microsomes. The enzymatic reaction required nicotinamide adenine dinucleotide phosphate (NADPH) and molecular oxygen, and showed an optimal pH around 7.3. The microsomal CBE-forming activities decreased in the following order; guinea pig greater than mouse greater than or equal to rabbit greater than or equal to rat. The CBE formation in the guinea pig hepatic microsomes was suppressed with various inhibitors of cytochrome P-450 such as SKF 525-A, alpha-naphthoflavone and carbon monoxide, but not by disodium ethylenediamine tetraacetate. When incubated with the microsomes either in the presence or absence of NADPH, a synthetic epoxide of CBD, 1S, 2R-epoxy-CBD-2',6'-diacetate was easily and exclusively converted to CBE. On the other hand, 1R, 2S-epoxy-CBD was not changed to CBE at all, but to several oxidized metabolites. These results suggest that CBD is biotransformed to 1S,2R-epoxy-CBD with hepatic microsomal monooxygenase system including cytochrome P-450, and the epoxide is immediately converted to CBE.

Animals↗
PubMed1989

Characteristics of the gastrointestinal absorption of morphine in rats.

The absorption characteristics of morphine were investigated by using rat gastrointestine. Absorption and transport experiments were carried out by the in situ loop and the in vitro everted sac methods, respectively. Brush border membrane vesicles (BBMVs) were used for uptake experiments. Morphine and its metabolites, morphine-3-glucuronide (M-3-G), and morphine-6-glucuronide (M-6-G), in biological samples were simultaneously determined by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and electrochemical detection. In the in situ loop method, morphine was well absorbed in the order of jejunal site greater than duodenal site greater than ileal site greater than middle intestinal site greater than rectal site, but it was poorly absorbed from the stomach. In each of the everted duodenal and jejunal sacs, 2,4-dinitrophenol, a metabolic inhibitor, inhibited the transport of morphine from the mucosal side to the serosal side. Further, HgCl2 pretreatment reduced the absorption of morphine from the duodenal and the jejunal loops. The initial uptake of morphine by BBMVs was stimulated in the presence of an H+ gradient (inner pH 7.5 and outer pH 5.0) and an overshoot phenomenon was observed. The initial uptake showed concentration dependence, i.e., it was saturable. Results obtained in this study indicate that carrier-mediated transport stimulated by the H+ gradient is partly involved in the duodeno-jejunal absorption of morphine, although morphine is passively absorbed from other sites.

Animals↗