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Biomedical subjects

M Yamazaki

Publications and source records attributed to M Yamazaki.

At least 613 records · Page 34Linked to original sources
PubMed1991

The risk of cerebral infarction in non-valvular atrial fibrillation: effects of age, hypertension and antihypertensive treatment.

The stroke risk was studied on 600 subjects with nonvalvular atrial fibrillation (NVAF) compared with the general population. The age-matched relative risk of stroke was highest in the 41- to 50-year-old population (12.6) but decreased with age (8.2 for 51-60 years, 3.6 for 61-70 years, and 2.6 for 71-80 years) owing to the increase in stroke incidence with age in the general population. There was no particularly vulnerable period for stroke from NVAF diagnosis until the 15the year. Stroke incidence was greater in hypertensives than in normotensives, but was not different between treated and untreated subjects among hypertensives.

Adult↗
PubMed1991

Analgesic principles from Aralia cordata Thunb.

The analgesic principles from Aralia cordata Thunb, were identified with (ent)-kaur-16-en-19-oic acid (KA) and (ent)-pimara-8(14),15-dien-19-oic acid (PA), respectively. Both compounds were significantly effective regarding analgesics, hypothermia, duration of pentobarbital-induced anesthesia, and depression of locomotor activity enhanced by methamphetamine at doses of 300 mg/kg (KA) and 500 mg/kg (PA) by oral administration.

Analgesics↗
PubMed1991

Different modulation by cyclooxygenase inhibitors of the response to angiotensin II in monkey arteries and veins.

In coronary, renal and femoral arteries and mesenteric veins isolated from Japanese monkeys, tachyphylaxis to angiotensin (ANG) II (10(-7) M)-induced contraction rapidly developed. Contractions caused by ANG II in coronary arteries were attenuated by treatment with indomethacin and aspirin and also by endothelium denudation. Indomethacin inhibited the response of the arteries with and without endothelium to a similar extent. OKY 046, a thromboxane A2 synthesis inhibitor, failed to inhibit the response. In contrast, contractions of renal arteries were potentiated and prolonged by the cyclooxygenase inhibitors. ANG II-induced contractions of mesenteric veins were prolonged but those of femoral arteries were not altered by indomethacin. It is concluded that ANG II contracts monkey coronary arteries, possibly due to the release of vasoconstrictor prostanoids but not thromboxane A2 from endothelial and subendothelial tissues and also due to its direct action on smooth muscle, whereas contractions of renal arteries and mesenteric veins are blunted by vasodilator prostanoids, possibly PGI2. Cyclooxygenase products even if released do not appear to regulate femoral artery contractions produced by ANG II.

Angiotensin II↗
PubMed1991

A cyclic AMP phosphodiesterase inhibitor, 8'-pivaloyloxymethyl ester (POM-ester) of griseolic acid, lowers rabbit intraocular pressure.

The effects of griseolic acid (GA), a cyclic-AMP phosphodiesterase (PDE) inhibitor, and its 8'-pivaloyloxymethyl (POM) ester on intraocular pressure (IOP) in rabbits were investigated. When 50 microliters of 1 and 2% GA POM ester solutions were topically applied to one eye in normal rabbits, significant IOP decreases were detected at 2 hrs and at 1 to 5 hrs, respectively. Other than ocular hypotension, no other ocular effects were detected locally even after administration of 2% GA POM ester. A more marked reduction in IOP occurred after the intravitreal injection of the GA POM ester. IOP was also reduced when GA was used in an intravitreal injection but not when it was topically applied. The difference in permeability between GA and GA POM ester across the corneal epithelium may explain why GA failed to reduced IOP following topical administration. GA and the GA POM ester inhibited cAMP PDE in rabbit ciliary body at low concentrations, the I50 being 0.075 microM and 2.4 microM, respectively, with 0.25 microM cAMP as substrate. GA and the GA POM ester markedly increased cAMP levels in vitro in iris-ciliary body specimens. Possibly, GA POM ester or its analogues may represent a new mechanistic class of ocular hypotensive agents.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1991

[A case of theophylline-induced rhabdomyolysis following therapy of bronchial asthma].

A case of a 81-year-old asthmatic male with Theophylline-induced rhabdomyolysis was reported. After intravenous administration of 250 mg of Aminophylline, he developed muscle weakness in the lower extremities. Serum CPK was 31,450 IU, and other enzymes escaping from skeletal muscles were elevated. Serum and urine myoglobin were also elevated. Cessation of Theophylline administration and conservative therapy resulted in improvement of rhabdomyolysis without concomitant acute renal failure. The present case was the 11th case of Theophylline-induced rhabdomyolysis in the world and the second case Japan.

Aged↗
PubMed1991

[Diagnosis of pancreatic cancer using 201Tl-chloride and a three-head rotating gamma camera SPECT system].

201Tl SPECT was performed on 17 patients with pancreatic cancer or chronic pancreatitis using a three-head rotating gamma camera SPECT system. In 7 of 10 patients with pancreatic cancer, the lesions were clearly delineated by 201Tl SPECT. Whereas the lesion of 30 mm in diameter was visualized, a large tumor of 80 mm in diameter could not be visualized. Namely, it was thought that 201Tl uptake by pancreatic cancer might be well correlated with tumor blood flow and/or its histological subtype rather than with tumor size. In 5 of 7 patients with chronic pancreatitis, no uptake by the pancreas was shown. The sensitivity, specificity, and accuracy in diagnosing pancreatic cancer by 201Tl SPECT were 70%, 71%, and 71%, respectively. The present results obtained by 201Tl SPECT were thought satisfactory enough to evaluate pancreatic cancer under the present conditions where there was no useful imaging agent for visualizing pancreatic cancer by SPECT. 201Tl SPECT is expected to be a new diagnostic tool for investigation of pancreatic tumorous lesion.

Adenocarcinoma↗
PubMed1991

Statistical analysis of the ability of police dental surgeons in identification of dental filling materials.

The subjects, 77 police dental surgeons at 50 police stations in Kanagawa prefecture, were asked to identify either gold foil filling, gold inlay, palladium alloy inlay, silver alloy inlay, which had been filled in 5 human skulls. We conducted a statistical analysis of the dispersion of agreement rates in identifying the filling materials according to their clinical career. The results showed that the rates for gold inlay and gold foil filling were higher than those for silver alloy inlay and palladium alloy inlay. However, it was concluded that caution is necessary in identifying elaborately-finished fresh filling materials.

Adult↗
PubMed1991

[A case of mitochondrial encephalomyopathy with schizophrenic psychosis, dementia and neuroleptic malignant syndrome].

A 37-year-old male with an 8-year-history of schizophrenic psychosis and dementia developed hyperpyrexia and cataleptic rigidity during haloperidol administration. He was transferred to our hospital where he was noticed to have generalized muscle weakness and atrophy. In his muscle biopsy, there were numerous ragged-red fibers and focal cytochrome c oxidase deficiency. In addition, the presence of strongly SDH-reactive blood vessels (SSV) in his muscle biopsy suggests that the similar systemic vascular abnormality as seen in MELAS plays a certain role for inducing the central nervous system symptoms. He discontinued haloperidol, and was placed on coenzyme Q and idebenone which were effective for his psychic problems. Several months later, his schizophrenic symptom disappeared and mental status improved from IQ of 60 to 68. We would emphasize that mitochondrial encephalomyopathies must be taken into account for differential diagnosis for psychiatric patients with mental deterioration.

Adult↗
PubMed1991

TNF-driven inflammation during mouse liver regeneration after partial hepatectomy and its role in growth regulation of liver.

To determine the role of TNF-driven inflammation in self-regulation of cell growth and differentiation, mouse liver regeneration after partial hepatectomy was examined for TNF-driven inflammation. Hepatectomy provoked priming state for TNF production in both whole body and liver on day 3 when the peak mitotic response occurred. Histochemical studies of liver also showed an inflammatory symptom; hepatocellular necrotic foci appeared by 6 hours after hepatectomy. TNF itself was secreted spontaneously in liver transiently on day 1 to 2 after hepatectomy just before the proliferation of hepatocytes. Dexamethasone reduced both TNF secretion and hepatocyte proliferation after hepatectomy. Recombinant murine TNF stimulated the in vitro proliferation of hepatocytes. These findings indicate that hepatectomy induces short-term secretion of TNF in liver and TNF-driven inflammation has an important role in liver regeneration, at least in part by the direct stimulation of hepatocyte proliferation.

Animals↗
PubMed1991

[Lyme disease with the triad of neurologic manifestations].

A 40-year-old man developed progressive neurologic manifestations following a tick bite with subsequent localized erythema migrans. These manifestations included bilateral sensory radiculoneuritis (T7-12), rectovesical dysfunction, paraparesis, right facial palsy and nuchal rigidity. Both serum and cerebrospinal fluid titers of IgG antibody against Borrelia burgdorferi were 1:8,192 using indirect immunofluorescence assay. No IgM antibody was detected. With high-dose intravenous penicillin and corticosteroid treatment the neurologic symptoms and signs gradually subsided, with a corresponding decrease in the IgG antibody titers. Among the cases of Lyme disease reported so far in Japan, the present case seems to be typical and serious in terms of the severity of nervous system involvement and the intensity of the antibody response.

Adult↗
PubMed1991

[Two autopsy cases of sudden death from dilated cardiomyopathy: calmodulin staining as an index of myocardial injury].

Thirty-four years old man and fourty-one years old man were suddenly died after exercise and drinking, respectively. Autopsy and microscopic examinations showed severe cardiac dilatation and fibrosis in both cases. Myocardial degeneration was observed only in the former case. Decreased (diffusion) or increased staining for calmodulin was observed in association with contraction band necrosis. The decrease and increase in calmodulin staining is thought to represent necrosis and calcium-overload, respectively. Both cases were diagnosed to have died from dilated cardiomyopathy without particular histories and causes.

Adult↗
PubMed1990

Functional expression from cloned cDNAs of glutamate receptor species responsive to kainate and quisqualate.

The complete amino acid sequences of two mouse glutamate receptor subunits (GluR1 and GluR2) have been deduced by cloning and sequencing the cDNAs. Xenopus oocytes injected with mRNA derived from the GluR1 cDNA exhibit current responses both to kainate and to quisqualate as well as to glutamate, whereas oocytes injected with mRNA derived from the GluR2 cDNA show little response. Injection of oocytes with both the mRNAs produces current responses larger than those induced by the GluR1-specific mRNA and the dose-response relations indicate a positively cooperative interaction between the two subunits. These results suggest that kainate and quisqualate can activate a common glutamate receptor subtype and that glutamate-gated ionic channels are hetero-oligomers of different subunits.

Amino Acid Sequence↗
PubMed1990

Postnatal development of crossed and uncrossed corticorubral projections in kitten: a PHA-L study.

Morphological changes in individual corticorubral fibers and the pattern of crossed and uncrossed corticorubral projections were studied during the postnatal development of cats in order to understand cellular mechanisms for restriction of corticorubral projections with development. The anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) was injected into restricted areas of the pericruciate cortex in kittens and PHA-L-labeled axons in the red nucleus were examined at postnatal days (PND) 7-73. In accordance with our previous study (Murakami and Higashi, Brain Res. 1988; 447:98-108), a crossed corticorubral projection was observed in addition to the uncrossed one in every experimental animal. During the early period of development (PND 7-8), swellings of irregular shape were observed along the entire course of the axons and they were often interconnected with extremely fine axonal segments. These axons bifurcated only infrequently and often ended as growth cones. These features were common to both uncrossed and crossed corticorubral axons. At later stages of development (PND 28 or later), the total number of swellings decreased and axonal swellings with smooth contours became dominant. A quantitative examination of axonal branches indicated that axons on the ipsilateral side branch occurred more frequently at later stages of development. However, there was no substantial change in branching frequency for the crossed corticorubral fibers during development. In parallel with morphological changes in individual axons, the crossed projection that was initially relatively abundant was reduced during development. Since a PHA-L injection can be confined to a small region of cortex, topographic projections can easily be detected. At PND 7-8 there was no well-defined topographic order in the ipsilateral corticorubral projection. Adult-like topography was first discernible at PND 13. These observations suggest that the unilateral uncrossed corticorubral projection in the adult cat is achieved at least in part by the formation of axonal arbors in the uncrossed projection. This was accompanied by the failure of crossed fibers to form complex arbors. It is possible that a similar mechanism also operates in the formation of topographic maps.

Aging↗
PubMed1990

Comparison between extracellular and tissue fluctuation of dopamine and related metabolites in striatum under hypoxia.

The time course of changes in both extracellular and tissue levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum of halothane-anesthetized rats was compared under hypoxic conditions. A 100-fold increase in the extracellular DA was observed within 20 min of hypoxia, while the tissue DA showed a 1.2-fold increase at the maximum. The inhibition of oxygen-dependent enzymes gives no satisfactory explanation for the acute DA increase, the disruption of DA uptake mechanisms may also participate in this.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

Tissue-selective inhibition of cholesterol synthesis in vivo by pravastatin sodium, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor.

Tissue selectivity of pravastatin sodium (pravastatin) in inhibition of cholesterol synthesis was investigated and its effect was compared with other 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, such as lovastatin, simvastatin and ML-236B. Inhibition of cholesterol synthesis in vivo was measured by incorporation of radioactivity into the sterol fraction 1 h after intraperitoneal injection of [14C]acetate to mice. The drugs were orally administered to mice 2 h before the acetate injection. When pravastatin at a dose of 20 mg/kg was administered to mice, about 90% inhibition of cholesterol synthesis was observed in liver and ileum, but the inhibition was less than 14% in kidney, spleen, adrenal, testis, prostate and brain. This tissue selectivity of pravastatin was also demonstrated even in varying doses (5-100 mg/kg) and time (75-180 min) after drug administration. Other 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors did not show such a tissue-selective inhibition of sterol synthesis under the same conditions. These results obtained with the in vivo study were confirmed in vitro by the inhibition of sterol synthesis in various cultured cells and rats lenses, as well as by cellular uptake of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors.

Acetates↗
PubMed1990

[A case of young woman with giant ovarian tumor as the manifestation of leukemic recurrence].

Following rapid development of chemotherapy to leukemia, reports about tumor-forming-leukemia are on the increase. But ovarian tumor-forming-leukemia is relatively rare, hence not enough is known about it. Recently, the authors experienced a case of young woman with recurrent leukemia which manifested as a giant ovarian tumor. She suffered from acute lymphocytic leukemia (ALL) in February, 1986, and received chemotherapy (predonisolone and cytocine arabinoside) until complete remission in peripheral blood. But she developed a giant abdominal tumor in May, 1988, and admitted to our hospital for close examination and treatment. Preoperative blood examination was within normal range, and peripheral blood smear revealed no leukemic blasts. She had a giant abdominal tumor occupying whole abdominal cavity, and the tumor showed solid pattern in ultra-sonography, CT and NMR-CT. Malignant lower abdominal tumor was suspected, and simple abdominal hysterectomy, bilateral salphingo-oophorectomy and omentumectomy was performed on 27th. May, 1988. A giant abdominal tumor developed from left ovary, infiltrating to the uterus through left Fallopian tube, and metastatic lesion at omentum were present. Postoperative pathological findings in immunochemistry showed that the tumor was recurrence of ALL as tumor-forming-leukemia. After operation, she was treated in the department of internal medicine for postoperative chemotherapy (TCMP-therapy 1 kur) and discharged in December, 1988. She is alive and healthy 10 months after operation, and reveals no signs of recurrence. It was important to recognize lower abdominal tumor in leukemic patients as gynecologic problem, and significance of surgical approach to ovarian tumor-forming-leukemia was indicated.

Adult↗