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Biomedical subjects

J Suzuki

Publications and source records attributed to J Suzuki.

At least 19 recordsLinked to original sources
PubMed1992

[Analysis on combined effect of X-rays with 5-FU on rat subcutaneous gliomas].

In a series of experiments on the combined use of radio- and chemotherapy for malignant glioma, X-rays combined with ACNU or 5-FU treatment caused a supra-additive effect on multicellular spheroids in vitro. In the present experiment, the effect of X-rays combined with 5-FU treatment on subcutaneously transplanted rat gliomas of RGC-6 cells was analyzed. The dose-survival curve for X-rays given to tumors in air-breathing rats was biphasic with a terminal slope (D0 = 4.3 Gy) that was parallel to that for tumors in previously killed rats. The hypoxic cell fraction thus obtained from the ratio of the surviving fraction in two parallel curves at 20 Gy was about 7% in the subcutaneous tumors in air-breathing rats. X-ray-induced, potentially lethal cellular damage recovered within 8 hours in these tumors. The surviving fraction of cells in the tumors decreased to a minimum at 4-6 hours after a 5-FU injection, but increased thereafter. A biphasic dose-response curve for 5-FU was also obtained for cells in these tumors, indicating the presence of 5-FU resistant cells. The effect of X-irradiation given at about 8 hours after a 5-FU injection was greater than the additive effect of both agents acting independently. This was true when an X-ray dose of more than 5 Gy was given.

Animals↗
PubMed1992

An overview on Takayasu arteritis.

Takayasu arteritis is a non-specific inflammatory disease of unknown etiology. It was first recognized as having a peculiar wreath-like arteriovenous anastomosis around the papillae of the retina by a Japanese ophthalmologist, Dr. M. Takayasu in 1908. A Japanese research committee reported more than 5,000 cases. For a supplement issue on Takayasu arteritis, this brief overview article has been written as an introduction to the disease.

Aorta, Thoracic↗
PubMed1992

Mutagenicity assay for nitroarenes of air pollutants held in leaves of woody plants.

A new method was developed for the detection of mutagenic nitroarenes held in the leaves of woody plants using a small amount of leaves. This method consists of extraction of mutagen from fresh leaves (15-30 g) by ultrasonication with ethyl acetate and purification by elution with benzene on a silica gel column to remove such inhibitory components for mutagenesis as chlorophyll. The mutation assay uses the new Salmonella typhimurium strains YG1021 (a nitroreductase-overproducing strain of TA98) and YG1024 (an O-acetyltransferase-overproducing strain of TA98), which are very sensitive to some nitroarenes in the absence of S9, and standard strain YG1020 (TA98 containing pBR322-Aps) for comparison. This method was applied to woody plants growing on various sites in the Tokyo metropolitan area and the suburbs. It was shown that the leaves of all woody plants tested contained different amounts of mutagens, probably mutagenic nitroarenes, depending upon their growing sites.

Air Pollutants↗
PubMed1992

Bilateral metastatic sclerochoroidal calcification in a patient with hyperparathyroidism.

We present the case of a 39-year-old man with bilateral sclerochoroidal calcification with primary hyperparathyroidism. Both the calcium and parathyroid hormone levels were elevated. Funduscopic examination revealed slightly elevated, multiple yellow lesions in both eyes. Fluorescein angiography showed filling defects of the choroid. Ultrasonography showed elevated, highly reflective lesions, and a computed tomography scan of the globe disclosed sclerochoroidal lesions with high density. We discuss the mechanism of sclerochoroidal calcification.

Adult↗
PubMed1992

Accentuated vagal antagonism of beta-adrenergic effects on ventricular repolarization. Evidence of weaker antagonism in hostile type A men.

BACKGROUND: Prior research has suggested a weaker parasympathetic antagonism of sympathetic effects on the heart in type A (coronary-prone) men. To confirm this phenomenon and extend our understanding of it, we investigated the effects of prior muscarinic blockade on the electrocardiogram T wave and other cardiovascular and neuroendocrine responses to isoproterenol in type A and type B (non-coronary-prone) men. METHODS AND RESULTS: Responses to two 5-minute intravenous isoproterenol infusions (0.01 micrograms/kg/min and 0.02 micrograms/kg/min) were evaluated in six type A and six type B men after pretreatment with either dextrose placebo or atropine (1.2 mg). Atropine significantly potentiated T wave attenuation in the recovery period after isoproterenol infusion (0.30 +/- 0.07 mV) compared with placebo (0.54 +/- 0.09 mV, p less than 0.001). Atropine also potentiated the heart rate increase to isoproterenol (39 +/- 3 beats per minute versus 20 +/- 2 beats per minute after placebo). Atropine enhanced decreases in systolic, diastolic, and mean arterial pressures as well as pulse pressure to isoproterenol. Atropine enhancement of many of these responses was increased among subjects with high scores on various hostility/anger scales. Isoproterenol alone produced greater T wave attenuation in type A than in type B men. However, atropine enhancement of T wave attenuation and blood pressure falls by isoproterenol was present only in type B men. CONCLUSIONS: These findings indicate that there is accentuated parasympathetic antagonism of T wave attenuation and blood pressure responses induced by beta-adrenergic stimulation. Relative weakness of this antagonism of sympathetic effects on the heart in hostile type A individuals may contribute to their higher coronary disease risk.

Adult↗
PubMed1992

Noninvasive assessment of cardiomyopathy development with simultaneous measurement of topical 1H- and 31P-magnetic resonance spectroscopy.

Background. It might be possible to estimate the metabolic derangement of cardiac muscle by topical nuclear magnetic resonance spectroscopy (MRS) in vivo without killing the animal. Methods and Results. By use of topical 1H- and 31P-MRS focused on the heart of Syrian hamsters with or without cardiomyopathy (CM; BIO 14.6 strain), the chemical constituents were measured in vivo nondestructively and repetitively at several stages of development of CM. A phantom experiment and two-dimensional plot of chain methylenes (CH2) of lipid/water ratio by 1H-MRS versus creatine phosphate (CP)/[beta-P]ATP ratio by 31P-MRS indicated that signal cross talk from the adjacent organs was negligible. Even before the onset of clinical or pathological manifestation of CM (7 weeks after birth), CH2/water ratio by 1H-MRS was lower in the CM group (7.3 +/- 0.7%) than in control (11.8 +/- 2.0%, p less than 0.05), and it decreased further at the hypertrophic stage (17 weeks, 4.1 +/- 0.7%, p less than 0.05) and the congestive stage (27 weeks, 4.3 +/- 0.9%, p less than 0.05). In contrast, the CP/[beta-P]ATP ratio by 31P-MRS started to decrease at the hypertrophic stage (1.90 +/- 0.18 versus 2.52 +/- 0.24, p less than 0.05) and decreased further at the congestive stage to 1.53 +/- 0.18 (p less than 0.01). These in vivo MRS data were confirmed by both biochemical assay and in vitro MRS analysis in heavy water after the animals were killed. Conclusions. A combination of topical 1H-MRS and 31P-MRS in vivo is promising for the noninvasive and sensitive assessment of cardiac muscle metabolism. Comparison of these MRS studies and biochemical analysis suggested not only the modification of water, lipid, CP, or ATP contents but also the reduction of flexibility or fluidity of lipids in cardiomyopathic heart.

Adenosine Triphosphate↗
PubMed1992

Homeostasis as regulated by activated macrophage. IX. Enhancement effect of LPSw (a lipopolysaccharide from wheat flour) on hen egg-laying and breaking strength of eggshell.

Oral administration of LPSw (a lipopolysaccharide from wheat flour) given at 60 micrograms/hen/d in drinking water, markedly enhanced eggshell strength. The monthly percentage of eggs laid with a shell strength of more than 4 kg to the total number of eggs was 32% in the group given LPSw in drinking water while it was 12% in the control group given plain water. At the same time, LPSw caused a 30% enhancement of total monthly number of eggs laid over that of control.

Animals↗
PubMed1992

3-anilino-L-alanine, structural determination of UV-5, a contaminant in EMS-associated L-tryptophan samples.

An aniline derivative which corresponds to UV-5 in the preceding paper was isolated from the case L-tryptophan sample associated with eosinophilia-myalgia syndrome (EMS). By spectroscopic analyses, the structure was identified as 3-anilinoalanine. The compound was optically active, and the stereochemistry of alanine moiety was determined as L, by comparing the specific rotation with a synthesized 3-anilino-L-alanine.

Alanine↗
PubMed1992

Characteristics of ventricular activation and recovery patterns in the rat.

Bipolar or unipolar epicardial and intraseptum electrograms were recorded from the in situ rat hearts with spontaneous sinus rhythm or myocardial electrical stimulation of 400 bpm in order to investigate the sequence and duration of cardiac activation in the rat. The ventricular epicardial isochronous maps in the rat showed the activation sequence comparable to those in humans and dogs, although the activation time (6 to 13 msec) of epicardium was approximately one-third of those of such species. The delay of activation between septum and ventricular surface in the rat was 5 to 8 msec, which was also shorter as compared with those in humans and dogs. However, the conduction velocity of the ventricular epicardium in the rat was approximately 40 cm/sec, mostly equal to that of humans. These findings might be accounted for by the possible presence of the bundle branch-purkinje system, at least functionally, similar to humans. The local QT interval in the septum were relatively longer (69 to 123 msec), compared with that of the ventricular surface (50 to 98 msec), and such durations of ventricular epicardium and septum were considerably less than those of dogs and humans. These results are consistent with the configuration of QRS-T on the limb lead ECG.

Animals↗
PubMed1992

Experimental investigation of a new liquid embolization method: enhancing effect of 25% ethanol on conjugated estrogen.

A new liquid embolization material applicable to intracranial lesions was evaluated by selective renal artery embolization in mongrel dogs. Absolute and diluted ethanol, estrogen, and estrogen in 25% ethanol (ethanol-estrogen) were injected. The embolization and side effects were investigated angiographically and histologically. Ethanol-estrogen caused similar embolization to absolute ethanol, but no direct damage to perivascular tissue, and is considered a promising embolization agent in intravascular surgery.

Animals↗
PubMed1992

Pyrimidine nucleoside monophosphate kinase isolated from pig brain homogenate catalyzes disproportionation of phosphate between two CDP molecules.

An enzyme fraction that catalyzes CTP formation from CDP was purified from pig brain homogenate to a single band on SDS-PAGE. The preparation had a molecular weight of about 36,000 and showed a high activity of phosphorylating CMP and UMP by ATP and turned out to be one of pyrimidine nucleoside monophosphate kinases. It also catalyzes UTP formation from UDP, although rather weakly. These characteristics show that the enzyme species from pig brain homogenate has a rather broad specificity toward phosphate donor in phosphorylating nucleoside monophosphate.

Animals↗
PubMed1992

[13-week subchronic toxicity study of 1,1-bis(t-butylperoxy) 3,3,5-trimethyl cyclohexane in mice].

A 13-week subchronic toxicity study of 1,1-bis(t-butylperoxy)3,3,5-trimethyl cyclohexane (TMCH) was performed in male and female B6C3F1 mice by feeding a CRF-1 powder diet containing 0, 0.5, 1.0, 2.0 and 4.0% TMCH, to determine the maximum tolerable dose (MTD) for subsequent carcinogenicity study. Mice were randomly divided into 5 groups, each consisting of 10 males and 10 females. Eight animals of both sexes in the 4.0% TMCH group died during the early administration period. Suppression of body weight gains was marked in both sexes of the 4.0% and 2.0% TMCH groups as compared with the control group. The mean food consumption in all groups treated with TMCH was lower than that in the control group in a dose-related manner. Hematological examination revealed decreases in the number of erythrocytes, volume of hemoglobin, and values for hematocrit and mean corpuscular volume (MCV) in both sexes of the 4.0% and 2.0% TMCH groups. The relative liver weights of all groups treated with TMCH increased in a dose-related manner, whereas both absolute and relative spleen weights decreased in a dose-dependent manner. Histopathologically, swelling of the hepatocytes was found centrilobularly or diffusely in both sexes of the 1.0, 2.0 and 4.0% TMCH groups, and decrease of the hematopoietic cells in the bone marrow was observed in both sexes of the 2.0 and 4.0% TMCH groups. In addition, atrophy of red pulp and white pulp of the spleen was found in both sexes of the 2% and 4% TMCH groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Characterization of murine hemopoietic-supportive (MS-1 and MS-5) and non-supportive (MS-K) cell lines.

Characteristics of hemopoietic-supportive (MS-1 and MS-5) and non-supportive (MS-K) cell lines were compared. Supportive cells adhered to hemopoietic stem cells and produced granulocyte-macrophage colony-stimulating factor (GM-CSF), whereas non-supportive cells did not adhere to hemopoietic cells and only produced macrophage colony-stimulating factor. Both cell lines produced substantial levels of IL-6 and steel factor (SLF) which is reportedly a stem-cell factor. Northern blot analysis revealed that SLF but neither c-kit nor interleukin 3 (IL-3) mRNA was detectable in these cell lines, although IL-3-like activity was found in the supernatant of MS-5 cell culture. These observations suggest that the hemopoietic-supportive function of stromal cells may reside in adherence of stem cells, and production of GM-CSF probably in combination with SLF. SLF may be transferred from stromal cells directly to stem cells through adhesion of stem cells to supportive stromal cells.

Animals↗
PubMed1992

[Gene rearrangement analysis of conjunctival malignant lymphomas].

Specific DNA probes for genes encoding immunoglobulins (Ig) and the T cell receptor (TCR) are useful diagnostic tools in lymphoproliferative disorders. Gene rearrangement analysis was carried out in 2 cases of conjunctival lymphoid lesions. A 36-year-old man (case 1) had a 1-year history of left conjunctival tumor. A biopsy was performed and histopathological findings showed diffuse proliferation of small lymphocytes, but monoclonality was not revealed by immunophenotypic analysis. A right conjunctival lesion developed and five months later a biopsy of the left conjunctiva was performed again. A frozen sample was analyzed and immunoglobulin heavy chain gene rearrangement was found. A 53-year-old woman (case 2) had a 6-month history of bilateral conjunctival tumor. The first biopsy did not reveal monoclonality immunophenotypically. A second biopsy with a frozen specimen was analyzed and immunoglobulin heavy chain gene rearrangement was found. We diagnosed these two cases as B-cell lymphoma. We discuss the clinical value of gene rearrangement analysis as a diagnostic method for lymphoproliferative disorders.

Adult↗
PubMed1992

Apolipoprotein(a) is present in urine and its excretion is decreased in patients with renal failure.

To investigate the relation between renal function and concentrations of lipoprotein(a) [Lp(a)] in serum, we measured Lp(a) in samples of serum and urine from patients with diabetes mellitus and in samples sent to a laboratory center for measurements of creatinine clearance. Serum Lp(a) concentrations were significantly increased in subjects with obvious renal dysfunction (serum creatinine > or = 176.8 mumol/L) compared with normal control subjects. Urinary Lp(a) excretion was decreased in subjects with obvious renal dysfunction compared with subjects without obvious renal dysfunction (serum creatinine < or = 88.4 mumol/L) and was negatively and positively correlated with serum creatinine and creatinine clearance, respectively. More than 80% of urinary Lp(a) was recovered in the d > 1.21 kg/L fraction. At least six bands for apolipoprotein(a) [apo(a)] fragments, which were smaller than native apo(a) in serum, were observed in urine by immunoblotting, and some of these were also detected in serum. Degraded apo(a) fragments are probably present in urine, and their excretion decreases in parallel with decreases in the glomerular filtration rate.

Adult↗