Search PubMed⌕ Search

Biomedical subjects

M Fujishima

Publications and source records attributed to M Fujishima.

At least 829 records · Page 46Linked to original sources
PubMed1985

Radiation-induced peroxidation of lipid dissolved in organic solvent and its inhibition by alpha-tocopherol and cepharanthine.

Effects of cepharanthine and alpha-tocopherol on radiation-induced peroxidation of lipids dissolved in methanol(MeOH)-chloroform (CHCl3)-H2O(v/v, 2/1/0.8) were examined. alpha-Tocopherol strongly inhibited radiation-induced peroxidation of lipids dissolved in MeOH-CHCl3-H2O. However, cepharanthine exhibited a weak inhibitory action in this system. The change in the absorption spectrum of alpha-tocopherol and cepharanthine by X-irradiation was measured. The reagents were dissolved in 95% EtOH acidified with 20 mM HCl and in MeOH-CHCl3-H2O. alpha-Tocopherol exhibited the change in its absorption spectrum in both systems, and seemed to be oxidized at a high rate by free radicals. However, cepharanthine slightly exhibited the change in its spectrum in MeOH-CHCl3-H2O, but not in acidified EtOH.

Alkaloids↗
PubMed1984

Cerebrospinal fluid lactate and pyruvate concentrations in patients with malignant hypertension.

Lactate and pyruvate concentrations and acid-base parameters in cerebrospinal fluid (CSF) and arterial blood were measured in 21 patients with malignant hypertension ( MHT ), 19 with benign hypertension (BHT) and 21 normotensive subjects (NT). Average values for CSF lactate and lactate/pyruvate (L/P) ratio were significantly higher in MHT (1.90 +/- 10 mM/1, 19.2 +/- 1.0) than in either BHT (1.50 +/- 0.05 mM/l, 15.7 +/- 0.7) or NT (1.44 +/- 0.04 mM/1, 15.7 +/- 0.4). There was a linear correlation between CSF lactate and CSF pressure (r = 0.565, P less than 0.01), and the latter was also related to mean arterial pressure exceeding 150 mm Hg (r = 0.553, P less than 0.01). Such increases in the acid metabolites in CSF indicate that brain metabolism becomes anaerobic in MHT , probably due to increased intracranial pressure. Increased cerebrovascular permeability is also discussed as participating in causal mechanisms.

Adult↗
PubMed1984

Autoregulation of cerebral blood flow in young and aged spontaneously hypertensive rats (SHR).

Autoregulation of cerebral blood flow (CBF) to the controlled hemorrhagic hypotension was studied in young adult spontaneously hypertensive rats (SHR, 3.4 months of age) and aged SHR (20.3 months). There were no differences in average values for mean arterial pressure and baseline CBF between two groups of rats. During hypotension, however, CBF was more reduced in aged SHR than in young SHR, indicating that the lower limit of cerebral autoregulation is shifted to a higher level in aged SHR. Such upward shift of the autoregulation is likely due to a long-lasting hypertension which may lead to the diminished vasodilatory response of the brain to hypotension.

Aging↗
PubMed1984

Pulmonary hemorrhage in experimental cerebral ischemia in mongolian gerbils. Brain metabolism and lung pathology.

Pulmonary changes in acute cerebral ischemia were studied in anesthetized Mongolian gerbils, in which both carotid arteries were occluded simultaneously. Lactate, pyruvate and adenosine triphosphate (ATP) in the brain were measured as indicators of the severity of cerebral ischemia. Microscopic changes in the lung were arbitrarily scored from 0 (normal) to 3 points (severely affected) by the grade and the extent of lesions. Mean arterial pressure (MAP) was also measured through the cannulated femoral artery before and after carotid artery occlusion in a separate group of animals. Cerebral lactate was increased while ATP decreased in ischemic animals in which pulmonary changes such as intra-alveolar hemorrhages were prominent and frequent. The lung pathology score averaged 1.3 in animals with severe ischemia (lactate greater than or equal to 10 mM/Kg), 0.7 in moderate ischemia (5-10 mM/Kg) and 0.3 in mild or no ischemia (less than 5 mM/Kg), respectively, suggesting that severe brain ischemia may cause fulminant pulmonary changes. The mechanism of pulmonary lesions in acute cerebral ischemia is discussed.

Adenosine Triphosphate↗
PubMed1984

[Central pontine and extrapontine myelinolysis following rapid correction of hyponatremia--report of an autopsy case].

A case of central pontine myelinolysis (CPM) following rapid correction of hyponatremia was reported and literatures were reviewed. The case was 61-year-old nonalcoholic female who had taken an operation of craniopharyngioma 23 years ago. Fifteen years later, she received re-operation for the recurrent tumor, followed by replacement therapy of corticosteroid and clofibrate. She was otherwise well until two weeks before entry, when she noticed abrupt onset of high grade fever, nausea, vomiting and general malaise. She was admitted to an emergency hospital because of weakness, disorientation and a slight impairment of consciousness, but she was able to speak and to take some food per os. Laboratory studies disclosed urinary tract infection and showed a serum sodium level of 117 mEq/l, potassium 2.9 mEq/l, a serum osmolarity 232 mO sm/l and urine osmolarity 141 mEq/l. She was diagnosed to have an exacerbation of adrenal insufficiency with hyponatremia and hypotonic dehydration triggered by urinary tract infection. Intravenous administration of vitamin B complex, electrolytes including KCL, 5% glucose solution and physiological saline with a large amount of corticosteroid was performed aggressively. Serum sodium concentration was raised to 161 mEq/l in two days, and the increased level had been maintained more than five days, resulting in coma and flaccid quadriplegia. During this period, there was no episode of hypotension, hypoglycemia, hypoxia nor hepatic failure which could have caused brain damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Insufficiency↗
PubMed1984

[Protective effects of 4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride (bifemelane) on acutely induced cerebral ischemia in Mongolian gerbils and spontaneously hypertensive rats (SHR)].

Effects of new antihypoxic agent (bifemelane) on survival and brain metabolism were studied in acute cerebral ischemia induced by bilateral carotid artery ligation in mongolian gerbils and SHR. Either 10 mg/kg or 30 mg/kg body weight of bifemelane solved in distilled water was intraperitoneally administered 1 hr in gerbils and 1.5 hrs in SHR prior to carotid ligation, and same amount of vehicle was also given in similar manner for control animals. Brain tissue metabolites such as lactate, pyruvate and ATP were determined by using the enzymatic technique in the ischemic brain frozen in situ 1 hr after carotid ligations in SHR. Mean survival times following carotid ligations were 186 +/- 255 min (+/- SD) in control gerbils, 429 +/- 455 min in those with 10 mg/kg of bifemelane, and 310 +/- 429 min in those with 30 mg/kg respectively, its difference between control and 10 mg/kg group being significant (P less than 0.05). Supratentorial lactate concentrations in the ischemic brains of SHR were substantially the same among the groups, whereas ATP levels were 0.62 +/- 0.24 mM/kg in control animals, 1.10 +/- 0.67 mM/kg in rats with 10 mg/kg of the drug, and 1.13 +/- 0.42 mM/kg in those with 30 mg/kg, respectively. In animals with a high dose pretreatment, the reduction of ATP was significantly smaller than that in control (P less than 0.02), indicating that this agent prevents a decline of high energy phosphate in the ischemic brain although anaerobic metabolites increase similarly in animals of all experiment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Sex difference of barbiturate-protection in experimental cerebral ischemia in spontaneously hypertensive rats (SHR).

Survival time following bilateral carotid occlusion was significantly longer in spontaneously hypertensive rats (SHR) anesthetized with barbiturate than in those with ether. Under barbiturate anesthesia, female SHR survived longer (16.6 h) than did males (10.9 h), whereas such sex difference was not found in those with ether anesthesia. The present results indicate sex difference of barbiturate-protection in cerebral ischemia.

Amobarbital↗
PubMed1983

Microspectrophotometric and autoradiographic study of the timing and duration of pre-meiotic DNA synthesis in Paramecium caudatum.

Timing and duration of pre-meiotic G1, S and G2 phases in Paramecium caudatum have been clarified by microspectrophotometry of DNA content and autoradiography with [3H]thymidine ([3H]dThd) and [3H]deoxyuridinemonophosphate ([3H]dUMP). Microspectrophotometric measurement of DNA content showed that cells in stationary phase have a G1 micronucleus, and that pre-meiotic DNA synthesis begins with the micronuclear swelling and ends immediately before the nucleus enters meiotic prophase. The results indicate that the micronucleus is in G1 during the first 1.5 h after onset of mating reaction at 25 degrees C and in pre-meiotic S phase during the following 1 h, and that G2 phase is very short or lacking. Therefore, in P. caudatum, the transition point from pre-meiotic interphase to meiotic prophase is at or very close to the end of pre-meiotic DNA synthesis. Autoradiographic study showed that although [3H]dThd and [3H]dUMP were well utilized in pre-mitotic DNA synthesis, only [3H]dUMP was well utilized in pre-meiotic DNA synthesis. [3H]dThd was utilized very little in pre-meiotic DNA synthesis even if the precursor was taken into the cell, suggesting that the activity of thymidine kinase is low in these cells.

Animals↗
PubMed1983

Infection of macronuclear anlagen of Paramecium caudatum with the macronucleus-specific symbiont Holospora obtusa.

The gram-negative bacterium Holospora obtusa is an endonuclear symbiont of Paramecium caudatum, which is incorporated into the host cells via the food vacuoles and infects their macronucleus exclusively, but never the micronucleus. Since these two kinds of nuclei originate from a fertilization nucleus, it is assumed that the macronucleus acquires a property necessary for it to be recognized by the bacterium at a certain time during the nuclear differentiation process. We found that this property is acquired by four of the eight postzygotic nuclei as soon as the four nuclei differentiate morphologically into the macronuclear anlagen.

Animals↗
PubMed1983

Conjugation and meiosis of Paramecium caudatum infected with the micronucleus-specific bacterium Holospora elegans.

Cells of two complementary mating types of Paramecium caudatum, syngen 3, are infected with the micronucleus-specific bacterium Holospora elegans. Cells with bacteria in their micronuclei show the mating reaction with agglutination and pair formation. All the stages of meiosis in this species are observed and pronuclei are formed. During the pregamic divisions the bacteria are distributed to the division products, but many of the bacteria remain within the separation spindles, later being released into the medium. Therefore, the pronuclei contain only a few or no bacteria. In a test of the viability of exconjugant clones CNR-mutant (a behavioral mutant) and wild type cells, both infected with H. elegans, are crossed. The survival of exconjugants is very low (10.6% compared to 57.3% in the control). After conjugation only parental types are found indicating the occurrence of macronuclear regeneration after conjugation. The same result is obtained with cells which had contained bacteria but were cured by means of antibiotics. It is concluded that infected micronuclei have become genetically defective and did not give rise of new functional macronuclei. Therefore, H. elegans-bearing paramecia are genetically dead, which shows the parasitic nature of the bacterium H. elegans.

Animals↗
PubMed1983

[A case of an incompletely duplicated ventral urethra].

A ventral incomplete duplicated urethra was found in a 20-year-old male. The accessory urethra lay ventral to and in parallel with the normal urethra. The external orifice of the accessory urethra was also ventral to the orifice of the normal urethra in the glans. On the other hand, the accessory urethra was closed near the bulbar region, and an abscess was found at the dead end. The accessory urethra, which was 9 cm long, was surgically removed. Histopathologically, the luminal surface was covered with a stratified squamous epithelium; and, smooth muscle and spongy tissue were observed around the accessory urethra. The classification of the duplicated urethra is discussed.

Adult↗
PubMed1983

[Effects of hypo- or hyperglycemia on brain metabolism in experimental cerebral ischemia].

Glucose, lactate, pyruvate and adenosine triphosphate (ATP) concentrations in the supratentorial brain tissue frozen in situ were measured one hour after bilateral carotid occlusion in spontaneously hypertensive rats, of which blood glucose levels were varied by intraperitoneally injected insulin (hypoglycemia), saline (normoglycemia) and 50% glucose (hyperglycemia). Cerebral glucose concentrations as well as blood glucose levels were significantly increased in hyperglycemic animals, and decreased in hypoglycemic ones. Cerebral lactate, and lactate/pyruvate ratio at one-hour ischemia tended to increase in hyperglycemic animals comparing with those in normoglycemic ones, although cerebral ATP levels were slightly higher in the former. In hypoglycemic animals with one-hour ischemia, cerebral lactate was less increased but ATP was significantly reduced. It has been reported that hyperglycemia has vulnerable effects on brain metabolism of complete cerebral ischemia, presumably due to hyperglycemia-induced lactic acidosis of the brain. In incomplete cerebral ischemia as demonstrated in the present study, however, ATP concentrations remained at slightly higher level, despite tendency to more increase in lactate in hyperglycemic animals, indicating that high blood glucose level might be beneficial, rather than vulnerable, to incomplete cerebral ischemia. On the other hand, hypoglycemia causes more severe impairment of the brain energy metabolism because of an insufficient supply of substrates to the brain.

Adenosine Triphosphate↗
PubMed1982

Stroke-prone spontaneously hypertensive rats as an experimental model of malignant hypertension. A pathological study.

A light-microscopic study of various organs of stroke-prone spontaneously hypertensive (SHRSP) rats was performed. The rats characteristically developed fibrinoid necrosis of the wall and marked cellular thickening of the intima and media of the arterioles and small arteries of the kidney, testicle, mesentery, adrenal gland, brain, etc. Parenchymal damage of the organs, secondary to the vascular alterations took place. There were no accumulations of lipids in the vascular lesions. Though stroke has been stressed as a characteristic clinical feature of the SHRSP rats, the cerebral lesions are different from those seen in ordinary cerebrovascular disease. Furthermore, many organs are involved. The overall vascular changes in the brain and other organs are consistent with those seen in malignant hypertension; the SHRSP rat is an excellent model of this disease.

Adrenal Glands↗
PubMed1981

Vascular changes underlying cerebral lesions in stroke-prone spontaneously hypertensive rats. A serial section study.

The relationship of the vascular changes to the cerebral lesions has been studied using serial sections of the brains from five cases of the stroke-prone spontaneously hypertensive rats. Infarction was observed in a form of microinfarct related to single or plural occluded arterioles in the brain and subarachnoid space. Though most arterioles with fibrinoid necrosis of the wall were occluded with thrombus, infarct, which was obviously related to the occluded arterioles, was verified only in a few occasions. It was proved that infarction did not develop in all the areas irrigated by the occluded arterioles, and the regional circulation was assumed to have been maintained by the collateral circulation. There was rarefaction of the neutrophil with preservation of the neurons in the cortex around the vascular changes, such as fibrinoid necrosis of the wall. Widespread rarefaction and cyst formation were observed in the subjacent white matter, which were more marked in the vicinity of the vascular changes in the cortex. These histological changes were interpreted to be the tissue degeneration secondary to edema.

Animals↗