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Biomedical subjects

Y Maki

Publications and source records attributed to Y Maki.

At least 127 records · Page 7Linked to original sources
PubMed1987

The effect of inhaled leukotriene D4, histamine, or antigen on central and peripheral airways of guinea pigs: analysis of bronchograms with an interactive image analysis system.

The effect on guinea pig airways of the inhalation of leukotrienes, histamine or antigen was investigated by measuring changes in lung volume and analyzing the airway area on bronchograms with the Zeiss interactive image analysis system (IBAS). LTC4, LTD4, LTE4 and histamine inhaled through an ultrasonic nebulizer caused inflation of the lung: LTD4 was the most potent of the leukotrienes and was 100 times more potent than histamine on a molar basis. The results of analyses of areas of large and small bronchi and bronchioles on the bronchograms indicated that LTD4 selectively decreased the area of the peripheral airways. Inhalation of an antigen in actively sensitized animals resulted in inflation of the lung and in a selective decrease in the area of the peripheral airways. Anaphylactic bronchoconstriction provoked by antigen inhalation was clearly inhibited by AA-861, a 5-lipoxygenase inhibitor but not significantly by mepyramine, an antihistamine. These observations indicate that LTD4 is a potent constrictor of the peripheral airways in guinea pigs and that the anaphylactic bronchoconstriction provoked by antigen inhalation could be mediated by LTD4 in actively sensitized guinea pigs.

Anaphylaxis↗
PubMed1987

Spinal antinociceptive effects of adenosine compounds in mice.

The effects of injecting ATP, ADP, AMP, adenosine and adenine intrathecally on the pain response induced by the injection of substance P (10 ng/mouse) intrathecally were studied. All the compounds except adenine inhibited the pain response in a dose-related manner. The ED50 values of ATP, ADP, AMP and adenosine were 2.10, 0.93, 0.88 and 0.48 micrograms/mouse, respectively. Pretreatment with theophylline at a dose of 100 mg/kg p.o. markedly diminished all the antinociceptive effects. The effect of adenosine was not affected by s.c. injection of naloxone. These results suggest the existence of adenosine receptors which modulate spinal nociceptive sensory processing, independently of the endogenous opiate system.

Adenine Nucleotides↗
PubMed1987

Actions of antisecretory agents on proton transport in hog gastric microsomes.

The properties of K+-stimulated ATP hydrolysis (K+-ATPase) and vesicular accumulation of H+ (H+ accumulation) in hog gastric microsomes were investigated. The microsomes consisted of smooth surfaced vesicular particles, 70-300 nm in diameter. Both the activities of ATPase and the vesicular accumulation of H+ were stimulated by K+ in the presence of Mg2+, and enhanced by the K+-ionophore, valinomycin. However, there were differences in regulation of K+-ATPase and H+ accumulation by K+ ions, i.e. K+ at concentrations higher than 10 mM decreased K+-ATPase activity but further enhanced H+ transport. This observation suggests that the two reactions are partly independent. The H+ accumulation was inhibited by omeprazole, fenoctimine, spermine, and NaSCN, but not by cimetidine, prostaglandin E2, and atropine. The inhibitory effect of omeprazole on H+ accumulation paralleled the inhibition of K+-ATPase, while fenoctimine, spermine, and NaSCN suppressed H+ accumulation, without inhibiting K+-ATPase, under appropriate concentrations. In addition, the spontaneous diffusion of H+ across the microsomal membrane was markedly enhanced by fenoctimine, but not by the other agents used. These results indicate that omeprazole inhibits H+ accumulation by inhibiting K+-ATPase, fenoctimine suppresses H+ accumulation mainly by increasing the loss of accumulated H+ from the microsomal vesicles, spermine and NaSCN reduce H+ accumulation by inhibiting the transport of H+ into microsomal vesicles.

Adenosine Triphosphatases↗
PubMed1987

A case of porencephaly associated with aneurysm.

A case of aneurysm of the middle cerebral artery with congenital porencephaly in the same region is reported. The cyst was opened and the aneurysm was wrapped with a muscle strip. The resected specimen of the cyst wall contained a parenchymal layer with hemosiderinladen macrophages. It is speculated that bleeding from the aneurysm during the perinatal period caused the porencephaly.

Brain Diseases↗
PubMed1987

Diabetes induced by neonatal streptozotocin treatment in spontaneously hypertensive and normotensive rats.

The development of non-insulin-dependent diabetes mellitus (NIDDM) induced by neonatal streptozotocin (STZ) treatment was compared between male spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). The animals were intraperitoneally given 37.5, 50.0, 62.5, or 75.0 mg/kg of STZ at two days of age. At two days after STZ injection, plasma glucose was elevated in both groups of rats according to the dose of STZ, but the level was higher in SHR than in corresponding WKY. At ten days of age, plasma glucose in WKY returned to the similar level to that in vehicle-treated control irrespective of the doses of STZ, while in SHR it remained above control and its level was significantly higher than that in WKY. At 12 weeks of age, plasma glucose was within the control range in WKY, while in SHR it was markedly and dose-dependently elevated. The present study indicates that SHR are susceptible to NIDDM induced by neonatal STZ treatment. The difference in response to STZ between SHR and WKY was discussed.

Aging↗
PubMed1987

Sex differences in diabetes induced by neonatal streptozotocin treatment in spontaneously hypertensive rats.

We examined the sex differences in the development of diabetes due to neonatal streptozotocin (STZ) treatment in spontaneously hypertensive rats (SHR) which are more prone to diabetes than normotensive rats. Male and female SHR were intraperitoneally injected with various doses of STZ at 2 days after birth. In those treated with vehicle or 25 mg/kg of STZ, there were no sex differences in plasma glucose levels, which changed little during the 12 weeks of observation. When treated with 50 mg/kg of STZ, however, male SHR developed overt hyperglycemia greater than 300 mg/dl plasma glucose after 8 weeks of age, while females showed a minimal change in plasma glucose levels. When given 75 mg/kg of STZ, female rats developed overt hyperglycemia at 4-6 weeks of age, during which time male SHR showed no apparent hyperglycemia. At 8 weeks or later, however, both males and females had similarly high levels of plasma glucose. Glycosylated hemoglobin at 12 weeks was compatible with plasma glucose levels in each group. The present results indicate that there are sex differences in susceptibility to neonatal STZ treatment and in development of hyperglycemia.

Aging↗
PubMed1987

A profile of plasma branched chain amino acids in a totally pancreatectomized patient: effects of glucagon replacement under a steady feeding state.

Physiological amounts of glucagon replacement brought about the reduction of plasma branched chain amino acid levels as well as glucogenic amino acid levels in a totally pancreatectomized patient who was under a steady feeding state, i.e., constant administration of an elemental diet combined with continuous subcutaneous insulin infusion. This finding suggests that glucagon may play a physiological role not only on glucogenic amino acids but also branched chain amino acids in plasma in feeding state.

Amino Acids, Branched-Chain↗
PubMed1987

Avian sarcoma virus 17 carries the jun oncogene.

Biologically active molecular clones of avian sarcoma virus 17 (ASV 17) contain a replication-defective proviral genome of 3.5 kilobases (kb). The genome retains partial gag and env sequences, which flank a cell-derived putative oncogene of 0.93 kb, termed jun. The jun gene lacks preserved coding domains of tyrosine-specific protein kinases. It also shows no significant nucleic acid homology with other known oncogenes. The probable transformation-specific protein in ASV 17-transformed cells is a 55-kDa gag-jun fusion product.

Amino Acid Sequence↗
PubMed1987

Ossification of the posterior longitudinal ligament: a clinico-radiological study of 74 cases.

A clinico-radiological analysis of 74 cases of ossification of the posterior longitudinal ligament is reported. Eighteen cases (24%) were asymptomatic or only had neck or shoulder pain; 16 cases (22%) showed signs of radiculopathy, and the remaining 40 cases (54%) had myelopathy. Ossification of the posterior longitudinal ligament developed most frequently at C5, and was rare in thoracic and lumbar regions. Ossification of the posterior longitudinal ligament led to stenosis of the spinal canal; more marked stenosis caused clinical myelopathy. The data showed that 30% of stenosis caused by ossification of the posterior longitudinal ligament was critical for the production of myelopathy.

Adult↗
PubMed1987

Mechanism of action of an antiallergic agent, amlexanox (AA-673), in inhibiting histamine release from mast cells. Acceleration of cAMP generation and inhibition of phosphodiesterase.

Amlexanox markedly inhibits histamine release from rat mast cells. To clarify the mechanism of this inhibition, we investigated the effect of amlexanox on cAMP content, which, when increased, inhibits histamine release in rat peritoneal mast cells. At concentrations of 10(-8)-10(-6)M, amlexanox or isoproterenol increased the cAMP content of mast cells over that of control cells about 2-fold. When the mast cells were incubated with 10(-8), 10(-7) and 10(-6) M of amlexanox combined with 10(-7) M isoproterenol, the cAMP contents were synergistically increased 15-, 60- and 88-fold, respectively. 3-Isobutyl-1-methylxanthine (IBMX) at 10(-6)-10(-4) M increased the cAMP content 1.7-3.8-fold, and a combination of 10(-4) M IBMX and 10(-7) M isoproterenol synergistically increased the cAMP content 41-fold. A combination of amlexanox and IBMX synergistically increased the cAMP content 19-fold. The increase in cAMP content, when amlexanox and isoproterenol were combined, was transient; it peaked at 0.5 min after the drugs were administered, then decreased to 20-30% of the peak value about 2 min later. Pretreatment of mast cells with amlexanox reduced the effect of the combination of amlexanox and isoproterenol, indicating tachyphylaxis; pretreatment with IBMX had no such effect. The cAMP content of macrophages was also increased by amlexanox, but when combined with isoproterenol or PGE2, the effect was additive. Amlexanox inhibited cAMP phosphodiesterase in rat mast cells; its IC50 value was 1.4 X 10(-5) M, and its inhibitory activity was half that of IBMX.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminopyridines↗
PubMed1987

Acute brain swelling during evacuation of subdural hematoma caused by delayed contralateral extradural hematoma: report of two cases.

Two patients experienced severe brain swelling during the evacuation of acute subdural hematomas. Postoperative computed tomographic (CT) scans revealed delayed extradural hematomas on the sides opposite the subdural hematomas. Extradural bleeding occurred in the area of the fractured skull. One patient improved neurologically after evacuation of the extradural hematoma, and the other was not operated because he was moribund. Drilling exploratory burr holes in the fractured area may have been a better strategy than awaiting a postoperative CT scan. The reduction of intracranial pressure after the removal of subdural hematoma was postulated to be the most important factor contributing to the formation of the extradural hematoma.

Acute Disease↗
PubMed1987

Pituitary adenoma composed of two compartments each secreting prolactin or growth hormone.

We report a case of pituitary adenoma with two compartments, i.e. a part within the sella turcica and a part infiltrating the sphenoid bone beneath the sella, producing growth hormone (GH) and prolactin. The patient had the amenorrhea-galactorrhea syndrome, but not acromegalic symptoms. Although the two compartments were united through a small dural perforation, immunohistochemical studies demonstrated that GH and prolactin were separately secreted from the intrasellar and extrasellar components, respectively. Somatotropic adenomas frequently produce prolactin, but it is unusual for these hormones to be secreted from distinctly different parts of the same lesion.

Adenoma↗