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Biomedical subjects

T Shike

Publications and source records attributed to T Shike.

30 records · Page 2Linked to original sources

[A 54-year-old man with generalized muscle atrophy and oculomotor paresis].

We report a 54-year-old man with progressive generalized muscle atrophy and ophthalmoparesis in the terminal stage. He was well until 44 years of age (1982) when he noted weakness in his right hand and muscle atrophy; in May of 1985, he noted weakness in his left hand and in both legs. His weakness had become progressively worse, and he became unable to walk in November of 1985. He noted dysarthria one month later, and dysphagia in March of 1986. His difficulty in swallowing had also become worse; he regurgitated foods into the trachea in September of that year, and he developed a low grade fever on the same day. He was admitted to our service on September 24, 1987. On physical examination, general findings were unremarkable, except for low grade fever (37.3 degrees C). On neurologic examination, he was alert and mentally sound. He had normal vision and visual fields; ocular movements were normal. He had moderate weakness in facial muscles, dysarthria, dysphagia, and atrophy in his tongue. He had marked generalized muscle atrophy with fasciculation. He was unable to stand or walk. His muscle strength was not more than 1/6 in any part. The lower extremities were spastic. Deep reflexes were exaggerated in both lower extremities but were normal in upper extremities. Sensation was intact. Laboratory examination was unremarkable, and so was the cranial CT scan. He was treated with nasogastric feeding. He was able to communicate smoothly using his eyes, but a restriction in the vertical gaze was noted in February of 1989. The range of ocular movement was better in the oculocephalic reflex compared with his spontaneous vertical eye movements. In April of 1990, his horizontal gaze also had become slow, and he was complicated by bronchial asthma. He was treated with 20 mg/day of prednisolone; after the institution of prednisolone, his horizontal eye movement showed much improvement. In the terminal stage, he was able to move his eyes only very slowly; vertical gaze was impossible. His subsequent course was complicated by respiratory tract infection and septicemia, and he expired on July 15, 1992. The patient was discussed in a neurological CPC, and the chief discussant arrived at the conclusion that this patient had amyotrophic lateral sclerosis with oculomotor paresis. Post-mortem examination revealed spongy change involving the posterior column and the posterior spinocerebellar tract, in addition to severe degenerative change in the upper and the lower motoneurons, which were consistent with amyotrophic lateral sclerosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Amyotrophic Lateral Sclerosis↗

Platelet aggregation inhibitors in a Bhutanese medicinal plant, shug chher.

The 90% methanol-soluble fraction of a Bhutanese medicinal plant, Shug Chher, exhibited inhibition of platelet aggregation induced by platelet activating factor. Bioassay-directed fractionation led to the isolation of four new labdane diterpenoids, 3 alpha, 15-dihydroxy-labda-8(17), 13E-diene (5), 3 alpha-hydroxy-labda-8(17), 13E-dien-15-oic acid (6), 3 alpha-hydroxy-labda-8(17), 12E, 14-trien-19-oic acid (7), and 3 alpha-acetoxyisocupressic acid (8) and four known diterpenoids, manool (1), 3 alpha-hydroxymanool (2), 3 alpha-hydroxy-12, 13E-biformene (3), and isocupressic acid (4). The structures of the new compounds were determined spectroscopically. Compounds 2, 3, and 5 inhibited platelet aggregation.

Bhutan↗

Platelet aggregation inhibitors and inotropic constituents in Pyrolae herba.

The chloroform-soluble and n-butyl alcohol-soluble fractions of water extract of Pyrolae Herba inhibited platelet aggregation induced by arachidonic acid and showed a positive inotropic effect. A new naphthoquinone and a new tetralone derivative and known chimaphilin, acetovanillon, and toluhydroquinone were isolated as active constituents. Three new tetralone derivatives were also obtained from an active fraction. The structures of the new compounds were elucidated.

Animals↗

Platelet aggregation inhibitors from Populus sieboldii Miquel.

The water extract of Populus sieboldii Miquel (Salicaceae) inhibited arachidonic acid-induced platelet aggregation. Pyrocatechol and salicyl alcohol were isolated as active constituents. Pyrocatechol showed an inhibitory effect on platelet aggregation induced by arachidonic acid with IC100 value of 4 microM, which was 25 times more potent than aspirin.

Drugs, Chinese Herbal↗

[Effect of (+)-S-145 calcium salt dihydrate, an orally active antagonist of the thromboxane A2/prostaglandin endoperoxide receptor, on platelet aggregation].

The effect of (+)-S-145, (1R, 2S, 3S, 4S)-(5Z)-7-(3-phenylsulfonylaminobicyclo [2.2.1] hept-2-yl) heptenoic acid on human and guinea pig platelet aggregation was examined. (+)-S-145 sodium salt inhibited human platelet aggregation induced by arachidonic acid (AA), 9,11-methanoepoxy-PGH2 (U 46619), collagen, ADP or epinephrine with the IC50 being 0.047-0.146 microM in an in vitro system. When (+)-S-145 calcium salt dihydrate was administered orally to guinea pigs, it inhibited AA-, U-46619- or collagen-induced platelet aggregation dose-dependently with the minimum effective dose being 0.03 mg/kg, and the effective duration being maximally 3 hr. The inhibiting potency and effective duration of (+)-S-145 calcium salt dihydrate after multiple administrations, once a day (0.5 mg/kg) for 7 days, were almost the same as those after a single administration. Although (+)-S-145 sodium salt showed a partial agonist effect (shape change) on platelets in vitro, the effect diminished after pretreatment of the platelets with a lower dose of this compound. These data suggest that (+)-S-145 calcium salt dihydrate is an orally effective potent platelet aggregation inhibitor.

Adenosine Diphosphate↗

Effect of warfarin on plasma and liver vitamin K levels and vitamin K epoxide reductase activity in relation to plasma clotting factor levels in rats.

Changes in plasma and liver vitamin K1 and vitamin K1 epoxide levels, liver microsomal vitamin K epoxide reductase activity, and plasma clotting factor II and VII levels were determined in rats after a single injection of warfarin (2.5 mg/kg, s.c.). The plasma and liver vitamin K1 levels gradually decreased after warfarin injection, attaining the lowest values at 2-3 hrs and remaining low for 48 hrs. They then returned to the control levels at 72 hrs. The changes in vitamin K1 epoxide levels were opposite, with an increase being seen soon after the warfarin injection, the highest values at 3 hrs and a gradual decrease to the initial levels occurring subsequently. The combined levels of vitamin K1 plus vitamin K1 epoxide, however, remained almost constant in both plasma and liver after the warfarin injection. The liver vitamin K epoxide reductase activity decreased to its lowest level soon after the injection and then gradually increased after 12 hrs, but the activity at 72 hrs was only about 30% of the initial activity. The plasma clotting factor levels gradually decreased after the injection, bottomed at 24 hrs and then began to increase, recovering almost to the initial levels at 72 hrs. A positive correlation was found between plasma and liver levels for both vitamin K1 and vitamin K1 epoxide, and the slope of the vitamin K1 epoxide curve was steeper than that for vitamin K1 in the warfarin-treated rats. A similar positive correlation was found for both vitamin K1 and vitamin K1 epoxide after vitamin K1 injection in normal untreated rats, but the slope of the vitamin K1 epoxide curve was much shallower. These results suggest that warfarin inhibits vitamin K epoxide reductase and decreases blood clotting factor synthesis, thus increasing plasma and liver vitamin K1 epoxide levels. A vitamin K epoxide reductase activity one third of that in normal rats is sufficient to maintain normal reduction of vitamin K1 epoxide and synthesis of blood clotting factors.

Animals↗

[Effect of cefaclor on guinea pig platelet aggregation in vitro].

Effects of cefaclor (3-chloro-7-D-(2-phenyl-glycinamido)-3-cephem-4-carboxylic acid) on PAF, ADP, collagen, endotoxin, and thrombin-induced platelet aggregation were examined in vitro with the use of guinea pig platelet-rich plasma and washed platelets. PAF, even at concentrations lower than its minimum effective concentration, enhanced ADP- or endotoxin-induced platelet aggregation and prolonged the time to attain the maximum aggregation. PAF also enhanced collagen-induced platelet aggregation and shortened the lag time. Cefaclor (CCL) inhibited the PAF, ADP or thrombin induced platelet aggregation and shortened their maximum aggregation times at higher concentrations such as 300 micrograms/ml or more. CCL also inhibited the collagen-induced platelet aggregation and prolonged the lag time, but showed no effect on endotoxin-induced platelet aggregation. The effect of CCL was almost the same as that of latamoxef (LMOX). CCL and LMOX, however, showed no effect on cellular Ca2+ increase produced by PAF, ADP, or thrombin, suggesting that the inhibitory effect of CCL and LMOX on platelet aggregation is caused by the inhibition of fibrinogen binding to the glycoprotein IIb/IIIa complex.

Adenosine Diphosphate↗

[Effect of a new thromboxane A2 antagonist, S-145, on platelet aggregation].

The newly synthesized compound S-145, (+/-)-5(Z)-7-(3-endo-phenylsulfonylamino [2.2.1] bicyclohept-2-exo-yl)heptenoic acid, inhibited arachidonic acid (AA)-, 9,11-methanoepoxy-PGH2 (U46619)-, collagen- and ADP-induced human platelet aggregation in vitro with IC50 values of 0.25, 0.34, 0.22, and 0.08 microM, respectively. The inhibiting potency of this compound to AA- or U46619-induced platelet aggregation was about twice that of ONO-3708 and 1/7-1/14 that of SQ29,548 in human platelets, about 7 times that of ONO-3708 and 1/3-1/7 that of SQ29,548 in guinea pig platelets, and 250-800 times that of ONO-3708 and 1-7 times that of SQ29,548 in rabbit platelets. When S-145 was administered orally to guinea pigs at the dose of 0.1 mg/kg, AA-induced platelet aggregation was completely inhibited at 30 and 60 min after the administration, but not at 3 and 6 hr. The minimum effective doses of S-145 (p.o.) to AA- and collagen-induced platelet aggregation at 60 min after the administration were 0.01 mg/kg and 0.03 mg/kg, respectively. The potency of S-145 (p.o.) to inhibit AA- and collagen-induced guinea pig platelet aggregation was 30-300 times that of ONO-3708 or SQ29,548 and 300-1000 times that of aspirin. These results suggest that S-145 is a thromboxane A2 antagonist showing a potent inhibiting effect on platelet aggregation by oral administration.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

Effects of latamoxef on in vitro and ex vivo thromboxane A2 generation in human platelets.

Although beta-lactam antibiotics cause similar platelet abnormalities in vitro and in vivo, it is still unclear whether the mechanism(s) leading to the defects in both conditions are the same. The present work compared in vitro and ex vivo effects of latamoxef (LMOX) on aggregation and thromboxane (TX)A2 generation, determined as TXB2 generation. In the in vitro systems, LMOX interfered with both responses induced with all agonists tested (ADP, collagen and thrombin). Furthermore, although LMOX did not suppress arachidonic acid (AA)-induced TXB2 generation, it significantly suppressed the aggregation. In ex vivo systems performed with four healthy subjects, LMOX administration clearly suppressed the ADP-induced responses, but not the responses induced with the other agonists or AA. These differences observed in vitro and ex vivo are discussed from the viewpoint of different action mechanisms of LMOX under the two conditions.

Adenosine Diphosphate↗

Effects of 1-S replaced and/or decarboxylated latamoxef on rabbit platelet aggregation in vitro.

Latamoxef, 1-S replaced and/or decarboxylated derivatives of latamoxef were examined for their effects on ADP-, collagen- and platelet activating factor (PAF)-induced rabbit platelet aggregation in vitro. The results were compared with those of cefotaxime, cefmetazole, carbenicillin and aspirin. Latamoxef produced a dose-dependent inhibition of platelet aggregation at concentrations over about 4 mM, and the potency was almost similar to that produced by the other beta-lactam antibiotics, although the inhibiting effect of ADP-induced aggregation was more potent for latamoxef, whereas that on collagen-induced aggregation was stronger for cefmetazole and carbenicillin. The inhibitory effect of beta-lactam antibiotics on collagen-induced aggregation was, however, much weaker than that of aspirin. With respect to drug potency, replacement of the oxygen atom in the oxacephem ring with a sulfur atom caused no significant change in ADP-induced aggregation or slightly stronger inhibition of collagen- and PAF-induced aggregations. The decarboxylated derivatives of latamoxef and the 1-S replaced analogue of latamoxef showed slightly weaker inhibition of ADP-induced aggregation, but much stronger inhibition of collagen- and PAF-induced aggregation than the parent compounds. These data suggest that 1) the oxygen atom in the oxacephem ring is not responsible for the inhibitory effect of latamoxef on platelet aggregation and 2) the carboxyl group in the amide side chain had no significant role in this inhibition.

Animals↗

Effect of latamoxef (moxalactam) and its related compounds on platelet aggregation in vitro--structure activity relationships.

Latamoxef, 1-S replaced and/or decarboxylated derivatives of latamoxef, compounds possessing a partial structure of latamoxef, and a beta-lactam ring-opened derivative of latamoxef were examined for their effects on human platelet aggregation in vitro. Latamoxef produced a dose-dependent inhibition of ADP-induced platelet aggregation at high concentrations over about 2000 micrograms/ml (or 4 mM), and the potency was similar to that produced by cefotaxime, carbenicillin or ceftizoxime. Replacement of the oxygen atom in the oxacephem ring with a sulfur atom caused no significant change in the potency. The decarboxylated derivatives of latamoxef and the 1-S replaced analogue of latamoxef showed stronger inhibition for both ADP- and collagen-induced aggregation than the parent compounds. The effects of the compounds possessing a partial structure of latamoxef were weaker than that of latamoxef, but the effect of the beta-lactam ring-opened compound was about 3-fold stronger than that of latamoxef. These data suggest that neither the oxygen atom in the oxacephem ring nor the carboxyl group in the amide side chain is responsible for the inhibitory effect of latamoxef on platelet aggregation.

Adenosine Diphosphate↗

Effect of sex hormones on hypoprothrombinemia induced by N-methyltetrazolethiol in rats.

N-Methyltetrazolethiol (NMTT) increased prothrombin time (PT) and decreased plasma factor VII and prothrombin levels only in vitamin K-deficient male rats. In female rats identical treatment with NMTT did not produce hypoprothrombinemia. Conventional and germ-free rats displayed no significant difference in the manifestation of hypoprothrombinemia, but the increase of PT in NMTT-treated vitamin K-deficient rats was greater in the germ-free males. Estradiol administration or castration of male rats retarded manifestation of vitamin K deficient syndromes such as increases of PT and activated partial thromboplastin time (APTT), decreases of plasma factor VII and prothrombin levels, and increases of plasma and liver descarboxyprothrombin (PIVKA) levels, and testosterone injection to the castrated rats restored these changes. In female rats testosterone treatment or castration enhanced the manifestation of hypoprothrombinemia and estradiol treatment to the castrated females retarded it. Gamma-glutamyl-carboxylase activity was increased by vitamin K-deficiency but not inhibited by testosterone or NMTT. These data suggest that estrogen protects the rat against manifestation of hypoprothrombinemia even with NMTT treatment, while androgen enhances vitamin K deficiency, and supplementation of vitamin K prevents its deficiency in NMTT-treated rats.

Animals↗