Biomedical subjects

M Ohshima

Publications and source records attributed to M Ohshima.

At least 73 records · Page 4Linked to original sources

PubMed1993

Active oxygen-induced modification alters properties of collagen as a substratum for fibroblasts.

Acid-soluble collagen from rat skin was modified by active oxygen in vitro, and properties of the modified collagen as a substratum for fibroblasts were studied. When collagen was treated with ascorbate-copper ion systems, cross-linking and a little degradation occurred rapidly. The cells attached but spread poorly on the modified collagen gel as compared with on the untreated collagen gel. On the other hand, when collagen was treated with H2O2-copper ion systems, only degradation of collagen molecule occurred rapidly. This treatment did not affect the attachment and spreading of the cells on the collagen gel, but when the incubation was continued for a long time, the cells migrated actively and gathered. Thymidine incorporation by the cells was suppressed on both modified collagen gels as compared with that on untreated collagen gel, and the extent of the suppression on the H2O2-copper-treated collagen was larger than that on the ascorbate-copper-treated collagen. These results indicate that the active oxygen-induced cross-linking and degradation significantly alter properties of collagen as a substratum for fibroblasts.

Animals↗

PubMed1993

trans-dominant interference with virus infection at two different stages by a mutant envelope protein of Friend murine leukemia virus.

A dominant negative mutant Friend murine leukemia virus (FMLV) env gene was cloned from an immunoselected Friend erythroleukemia cell. The mutant env had a point mutation which resulted in a Cys-to-Arg substitution at the 361st amino acid in the FMLV envelope protein (Env). The mutant Env was retained in the endoplasmic reticulum (ER) and accumulated because of its slow degradation. The NIH 3T3 cells expressing the mutant env were resistant to ecotropic Moloney MLV (MoMLV) penetration, suggesting that the mutant Env traps the ecotropic MLV receptors in the ER. When the mutant env gene was transfected into and expressed in the cells persistently infected with MoMLV, the wild-type Env was trapped in the ER, and the MoMLV production was suppressed. Thus, the mutant Env accumulating in the ER trans-dominantly and efficiently interfered with the ecotropic MLV infection at both the early and the late stages.

3T3 Cells↗

PubMed1993

Electrophysiologic study and ergonovine provocation of coronary spasm in unexplained syncope.

A total of 38 patients with syncope in whom a cause was not assigned or suggested by the initial history, physical examination and electrocardiography (ECG) were studied. Twenty-four patients underwent cardiac examination with Holter ECG, electrophysiologic testing with programmed ventricular stimulation (EPS) and/or coronary arteriography including ergonovine provocation (ergonovine CAG). The study with Holter ECG, EPS and ergonovine CAG yielded a presumptive diagnosis in 36 patients (36/38 = 95%), 11 with vasopastic angina, 7 with ventricular tachycardia, 4 with ischemic heart disease, 9 with sick sinus syndrome (SSS), 1 with drug induced SSS, 3 with A-V block, 1 with supraventricular tachycardia, 1 with hypertrophic cardiomyopathy, 1 with aortic valve stenosis and 1 with carotid sinus syndrome (included are 1 patient with ventricular tachycardia+ischemic heart disease, 1 with SSS+vasopastic angina and 1 with ventricular tachycardia+vasospastic angina). Therapy based on these findings provided complete symptomatic relief in all patients during a mean follow up of 25 +/- 10 months (range 5-45 months). In conclusion, EPS and ergonovine CAG are useful in the diagnosis and therapy of unexplained syncope.

Cardiac Catheterization↗

PubMed1993

Collagenase and collagenase inhibitors secreted by cultured human periodontal ligament cells.

We have developed a new assay method for collagenase activity, in the presence of two different types of collagenase inhibitors, in culture medium of periodontal ligament (PDL) cells. Human PDL cells were cultured with serum-free alpha-MEM for 5 days after reaching confluency, and the culture medium was then harvested. Collagenase and collagenase inhibitors in the medium were concentrated by ammonium sulfate precipitation. The precipitate was dissolved, and the suspension was applied to an Ultrogel AcA 54 column for partial purification. Collagenase inhibitor activity was detected as two peaks; a small inhibitor molecule of about 32 kDa sensitive only to dithiothreitol (DTT), and a large one of about 70 kDa considerably more sensitive to 4-aminophenylmercuric acetate (APMA) than to DTT. Therefore, pretreatment of the sample preparation with both DTT and APMA was necessary in order to inactivate the inhibitors prior to assay of latent collagenase. This observation indicates that PDL cells secrete collagenase and two collagenase inhibitors without any stimulation in vitro.

Cells, Cultured↗

PubMed1993

Gingival epithelial cells secrete a substance which increases the collagenolytic enzyme activity of periodontal ligament cells.

To examine whether the gingival epithelium provokes a loss of connective tissue attachment during periodontitis, periodontal ligament (PDL) cells and gingival fibroblasts (GF) were cultured with conditioned medium of gingival epithelial cells, and the collagenolytic activity of PDL cells and GF were examined, respectively. The epithelial cells were cultured in the presence or absence of lipopolysaccharide (LPS), and the respective conditioned media were added to the cultures of PDL cells and GF. The collagenolytic response of PDL cells to both of the conditioned media was 3- to 10-fold higher than that of each control, whereas the response of GF was only 1.4-fold higher. The LPS-stimulated epithelial conditioned medium showed a stimulation rate for collagenolytic activity similar to that of the LPS-free conditioned medium. These results suggest that human gingival epithelial cells, without LPS stimulation, secrete a substance which accelerates the collagenolytic enzyme activity of PDL cells for degradation of PDL fibers, in the absence of GF enzyme activity.

Cell Division↗

PubMed1993

[A case of dual origin of the left anterior descending coronary artery from the left and right coronary arteries with variant angina].

We present a case of a 68-year-old male inflicted with a rare anomaly of the coronary artery. He had been suspected to have worsening effort angina and underwent urgent cardiac catheterization. The coronary angiography revealed 75% stenosis in the first diagonal branch. The left anterior descending artery was terminated in the mid portion and did not reach the apex. Instead, an anomalous coronary artery from the portion just proximal to the right coronary artery reached the apex. After cardiac catheterization, nocturnal chest pain at rest started to occur frequently. We suspected that vasospasm may have occurred because ST segment elevations in leads II, III, aVF were recorded on the electrocardiogram. Administration of diltiazem (120 mg per day) suppressed angina. Exercise stress electrocardiogram and thallium-201 myocardial scintigram did not show apparent ischemia. This case suggests that we must consider the presence of coronary vasospasm even in patients with clinically-supposed effort angina, to be possibly due to vasospasm occurring in anomalous coronary arteries.

Aged↗

PubMed1992

Immediate effects of percutaneous transvenous mitral commissurotomy on pulmonary hemodynamics at rest and during exercise in mitral stenosis.

Hemodynamics were evaluated during exercise in 33 patients with mitral stenosis who underwent percutaneous transvenous mitral commissurotomy (PTMC). PTMC was performed using an Inoue balloon. Each patient underwent a supine ergometer exercise test before and on the day after PTMC. Ergometer work load was started at 20 W and increased in increments of 20 W at 3-minute intervals until terminated by the patient's fatigue or shortness of breath. Mitral valve area increased by 0.8 +/- 0.4 cm2 (1.1 +/- 0.3 to 1.9 +/- 0.4 cm2, p less than 0.001). Mean mitral pressure gradient decreased (12 +/- 5 to 6 +/- 2 mm Hg, p less than 0.001). Pulmonary arterial pressure significantly decreased and the cardiac index significantly increased both at rest and during exercise after PTMC. Before PTMC, the increases in pulmonary arterial pressure, total pulmonary resistance and pulmonary arteriolar resistance during exercise were greater in patients with a mitral valve area less than 1.0 cm2 than in patients with an area greater than or equal to 1.0 cm2. After PTMC, total pulmonary resistance still increased during exercise. However, pulmonary arteriolar resistance did not change during exercise in patients with a mitral valve area greater than or equal to 1.5 cm2, whereas it increased in patients with an area less than 1.5 cm2. An enlarged mitral valve area greater than or equal to 1.5 cm2, which may prevent pulmonary vasoconstriction and permits a greater increase in pulmonary blood flow during exercise, is considered a good result immediately after PTMC.

Cardiac Catheterization↗

PubMed1992

K-ras activation and ras p21 expression in latent prostatic carcinoma in Japanese men.

Twenty-three clinically silent prostatic carcinomas discovered in Japanese men at autopsy were surveyed for ras proto-oncogene mutations by mutation-specific oligonucleotide probe hybridization after polymerase chain reaction (PCR) amplification from a section of formalin-fixed, paraffin-embedded tissue. Six of the 22 that were satisfactory amplified contained activating point mutations in codon 12 of K-ras, a significantly higher frequency than has been reported in patients with clinically advanced disease in the United States. Of the six cases with activating point mutations in codon 12 of K-ras, one had a GGT----GAT transition, four had GGT----GTT transversions, and one had both GGT----GAT and GGT----GTT mutations. Sections from the same tissues were immunohistochemically stained with an anti-ras p21 antibody. Carcinoma cells stained for ras p21 to some degree in 13 cases. Immunohistochemically detectable expression of p21 was always focal and was not necessarily associated with K-ras mutation. K-ras oncogene activation in prostatic carcinoma appears to merit additional study as a significant event in the pathogenesis of this neoplasm.

Aged↗

PubMed1992

Balloon catheter with check valves for experimental relief of acute aortic regurgitation.

To evaluate the ability of a newly designed balloon catheter with check valves to temporarily relieve hemodynamic deterioration in acute aortic regurgitation, we produced an experimental model of acute aortic regurgitation in closed-chest dogs using endomyocardial biopsy forceps. Aortic regurgitation was produced until an increase in aortic pulse pressure of over 50% was achieved. Left ventricular end-diastolic pressure rapidly increased after the production of aortic regurgitation. Immediately after the catheter began functioning, pulse pressure decreased from 133 +/- 1 to 78 +/- 5 mm Hg (mean +/- SEM) and left ventricular end-diastolic pressure also decreased from 26 +/- 1 to 13 +/- 1 mm Hg. These effects lasted as long as the catheter functioned. Although a mild (21 +/- 8 mm Hg) pressure gradient between the left ventricular peak systolic pressure and the aortic peak systolic pressure was observed when this catheter was used, forward stroke volume was no less than in the group in which the catheter had not been used. These findings suggest that the balloon catheter with check valves may effectively reduce aortic regurgitation.

Animals↗

PubMed1992

Promoting effects of potassium dibasic phosphate on early-stage renal carcinogenesis in unilaterally nephrectomized rats treated with N-ethyl-N-hydroxyethylnitrosamine.

The effects of potassium dibasic phosphate (PDP), potassium aluminum sulfate (PAS) and copper sulfate (CS) on early-stage renal carcinogenesis were investigated in unilaterally nephrectomized male Wistar rats after N-ethyl-N-hydroxyethylnitrosamine (EHEN) administration. After feeding 1,000 ppm EHEN, or basal diet for 2 weeks and removal of the left kidney at week 3, male Wistar rats were divided into 8 groups of 20 rats each. These groups received the following dietary treatments: 50,000 ppm PDP, 50,000 ppm PAS, 5,000 ppm CS or basal diet, respectively, for 18 weeks from weeks 3 to 20. The average numbers of adenomatous hyperplasias counted as preneoplastic lesions in the EHEN with 50,000 ppm PDP group were significantly higher than in the EHEN alone group or the EHEN followed by 50,000 ppm PAS or 5,000 ppm CS group. The treatment with 50,000 ppm PDP induced renal calcification and promoted the development of preneoplastic lesions in unilaterally nephrectomized rats treated with EHEN, but that with 50,000 ppm PAS or 5,000 ppm CS did not.

Animals↗

PubMed1992

A case of vasovagal syncope with convulsions--the effects of midodrine hydrochloride.

A 42-year-old female had suffered from repeated syncope. She had vasovagal syncope with convulsions from vasodilatation and cardiac standstill which lasted for 9.8 sec. The 60 degrees head-up tilt test, nitroglycerin injection and isoproterenol infusion provoked vasovagal reaction. Although a beta blocker was not effective in preventing tilt-induced hypotension and bradycardia, midodrine hydrochloride (alpha-1 stimulant) or atropine prevented it. In this patient, insufficient constriction of capacitance vessels might have played an important role in activation of an inhibitory reflex from cardiopulmonary mechanoreceptors which caused hypotension and bradycardia.

Adult↗

PubMed1992

[Acute hemodynamic effects of pimobendan and captopril: a comparative study in the same patients with chronic heart failure].

In this study, the acute hemodynamic effects of pimobendan (2.5 mg), a new drug, was compared with that of captopril (12.5 mg) in the same 8 patients with chronic heart failure (NYHA class II-III); 3 with dilated cardiomyopathy and 5 with regurgitant valvular heart disease. The hemodynamics were serially assessed before and after drug administration for at most 6 hours. Pimobendan reduced mean blood pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, right atrial pressure, total systemic vascular resistance, and total pulmonary vascular resistance but it increased heart rate. By contrast, captopril reduced mean blood pressure and double product. No significant changes were noted in the cardiac index, stroke volume index, AV-O2 difference or the arterial oxygen pressure between the 2 drugs. In conclusion, pimobendan seems to function as a strong arterio-veno-dilator rather than as an inotropic agent in patients with chronic heart failure.

Aged↗

PubMed1992

Chemical carcinogenesis in the thyroid gland.

Chemical carcinogens and promoters in thyroid carcinogenesis may be divided into two types, one having goitrogenic effects, the other not having these effects e.g. phenobarbital, 4,4'-diaminodiphenylmethane. The influence of sex hormones like estrogen and testosterone remains unclear, although some thyroid tumors have estrogen receptors. Further studies in this area are necessary.

Animals↗

PubMed1992

[Sclerosing lipogranuloma of the male genitalia: report of 2 cases--review of 72 cases reported in Japan].

Two cases of male patients (49 and 36 y.o.) with sclerosing lipogranuloma of the genitalia are reported. They denied having received any injection of exogenous substances or having suffered from any trauma. We discuss the clinical features and review previously published papers reporting similar cases. We would like to propose that sclerosing lipogranuloma that is not caused by the injection of exogenous substances should be dealt with as a new disease entity.

Adult↗

PubMed1992

[Evaluation of infantile ventricular tachycardia by 201Tl myocardial SPECT].

201Tl myocardial SPECT findings in infantile ventricular tachycardia (VT) were examined. The subjects were 4 cases of infantile VT subjected exercise-loading 201Tl scintigraphy in 1990. These cases (3 males and 1 female) were aged 11-14 years, being persistent and non-persistent type VT (2 cases each). Echocardiography revealed no abnormal findings in these 4 cases. Exercise-loading was performed by means of sitting ergometer. ECG revealed sinus arrhythmia except for one case which throughout its course of treatment, had already been presenting ventricular extrasystole from before the exercise-loading. Myocardial SPECT revealed persistent defects (anteroseptal wall defects in three case). The above suggests that 201Tl myocardial SPECT enables us to search for etiology of VT, prognosis and the like.

Adolescent↗

PubMed1991

Multiple-needle insertion method in percutaneous ethanol injection therapy for liver neoplasms.

One of the shortcomings of percutaneous ethanol injection therapy (PEIT) is that many sessions are necessary to accomplish the treatment. In order to reduce the number of treatment sessions, we inserted two or three needles before injection of ethanol was begun. Using the multiple-needle insertion method, we markedly reduced the number of treatment sessions. Histopathologic examination, imaging techniques, and serum alpha-fetoprotein levels showed efficacy of PEIT using the multiple-needle insertion method. No serious complication occurred. Levels of transient pain, fever, and the feeling of intoxication did not seem to be different from those occurring with the conventional method. Multiple-needle insertion method may be valuable as a method for reducing the number of treatment sessions necessary and thus shortening the treatment period.

Carcinoma, Hepatocellular↗

PubMed1991

Relationships between serum thyroid stimulating hormone levels and development of thyroid tumors in rats treated with N-bis-(2-hydroxypropyl)nitrosamine.

Relationships between serum thyroid stimulating hormone (TSH) levels, carcinogen dose and development of thyroid tumors were studied in Wistar rats of both sexes treated with N-bis-(2-hydroxypropyl)nitrosamine (DHPN). DHPN (210 mg/100 g body wt) was injected i.p. weekly. Wistar rats were used, divided into five groups of males (M1-M5) and five groups of females (F1-F5). M1 and F1 received one injection of DHPN, M2 and F2 two injections of DHPN, M3 and F3 three injections of DHPN, M4 and F4 four injections, and M5 and F5 as control rats received saline vehicle. The resultant incidences of total thyroid tumors were 4% in group M1, 24% in M2, 80% in M3, 76% in M4, 0% in F1, 4% in F2, 20% in F3, 17% in F4 and 0% in M5 and F5. Thus dose dependence for DHPN carcinogenesis was found in both sexes for up to at least three injections of DHPN and in all cases males proved more susceptible than females. Similar results were gained for carcinomas treated separately. A sex difference in DHPN induction of thyroid tumor was thus shown for Wistar rats opposite to that reported to exist in humans. However, no clear relationship between dose of DHPN or incidence of thyroid tumors and serum TSH concentration was evident at the end of the experiment (week 30).

Adenoma↗

PubMed1991

Possible application to medium-term organ bioassays for renal carcinogenesis modifiers in rats treated with N-ethyl-N-hydroxyethylnitrosamine and unilateral nephrectomy.

The effects of the renal tumor promoters; beta-cyclodextrin (beta-C), DL-serine (DL-S), basic lead acetate (LA), trisodium nitrilotriacetate monohydrate (NTA) and potassium bromate (KB), and diethylene glycol (DEG) as a negative control, on early stage of renal carcinogenesis were investigated in unilaterally nephrectomized male Wistar rats after N-ethyl-N-hydroxyethylnitrosamine (EHEN) administration. Wistar male rats were fed 1000 ppm EHEN diet for 2 weeks and the left kidney was removed at week 3, then the animals were divided into 7 groups of 15 rats each. These groups received the following treatments: 1000 ppm LA, 10000 ppm NTA or 500 ppm KB diet for 18 weeks from week 3; 45 mg/100 g body wt./day of beta-C injected sc for 7 days; 100 mg/100 g body wt. of DL-S injected sc biweekly for 6 weeks; 5% DEG in drinking water as a negative control for two days. Five rats in each group were killed at weeks 8, 12 and 20 and their kidneys were examined histologically. At week 20, the average numbers of adenomatous hyperplasias seen as preneoplastic lesions in the beta-C, DL-S, LA, NTA or KB groups were significantly higher than those in the DEG or control groups. Thus within a relatively short period of 20 weeks, promoting effects of chemicals can be detected as a significant increase of adenomatous hyperplasias in this model.

Animals↗