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Biomedical subjects

K Tamura

Publications and source records attributed to K Tamura.

At least 901 records · Page 50Linked to original sources
PubMed1992

[Management of elderly patients with aneurysmal subarachnoid hemorrhage].

Clinical features of 61 elderly patients aged over 70 years with ruptured intracranial aneurysms were compared with those of 328 younger patients aged under 70 years. According to a policy of early operation, elderly patients with Hunt and Kosnik's grade I, II and younger patients with grade I, II, III were operated on in the acute stage. In elderly patients with grade III, IV and younger patients with grade IV, the indication for surgery was determined case by case. Surgery was performed on 29 patients (48%) in the elderly group and 277 patients (86%) in the younger group. Our conclusions are as follows: 1. Regarding cases of grade I, II and III of Hunt and Kosnik's classification, the rate of good outcome in the elderly group was similar to that in the younger group, following early surgery and meticulous post-operative care. 2. In the elderly group, no patient in cases of grade IV obtained good surgical outcome. 3. Symptomatic vasospasm was less frequent in elderly patients (18.8%) than in younger cases (37%). 4. Delayed operation was planned for some patients in the elderly group, but none of them underwent surgery because of rerupture of aneurysms and deterioration of general condition.

Adult↗
PubMed1992

[The immunosuppressive acidic protein in the vitreous of fundus diseases].

Immunosuppressive acidic protein (IAP) is known to be a useful marker for malignant tumors and inflammatory diseases. We have previously reported that serum IAP level was increased in cases of Behçet's disease, especially in the acute phase, and those of retinoblastoma with extraocular infiltration. We assayed IAP levels in the vitreous body of various ocular diseases, including five cases of proliferative vitreoretinopathy (PVR), five cases of vitreous hemorrhage including four cases of branch retinal vein occlusion (BRVO) and one case of Terson's syndrome, four cases of proliferative diabetic retinopathy (PDR) and five cases of acute retinal necrosis syndrome. The single radial immunodiffusion method was used. The vitreous IAP level ranged from 5 to 130 micrograms/ml according to each case. Statistical analysis revealed that the vitreous IAP level was significantly higher in the group of PDR (p less than 0.05) and in the group of acute retinal necrosis syndrome (p less than 0.01) compared to the group of vitreous hemorrhage. In all cases, serum IAP levels were within normal limits. These results suggested that IAP might be produced within the ocular tissue, possibly by the activation of suppressor macrophages and migration of polymorphonuclear leukocytes in the vitreous with pathologic condition.

Adult↗
PubMed1992

General pharmacology of the new quinolone antibacterial agent levofloxacin.

The general pharmacological properties of (-)-(S)-9-fluoro-2,3-dihydro-3- methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de][1,4] benzoxazine-6-carboxylic acid hemihydrate (levofloxacin, DR-3355, CAS 100986-85-4), an optically active isomer of ofloxacin, were examined. 1. Central nervous system (CNS): DR-3355 at 200-600 mg/kg p.o. showed depressant activity on the CNS, as was indicated by the depressant syndrome (mice), decreased spontaneous motor activity (mice) and hypothermia (mice and rabbits). In the cat behavior and EEG experiments, it had both stimulant and depressant effects at 30-100 mg/kg i.p., and caused transient slow waves followed by seizures at 20-30 mg/kg i.v. DR-3355 had no effect on convulsion, hexobarbital anesthesia, pain reaction to a tail pinch, or conditioned avoidance response, except that it showed mild analgesic activity in acetic acid writhing at 600 mg/kg p.o. 2. Respiratory and cardiovascular system: DR-3355 produced a hypotensive and a bradycardiac effect after the rapid i.v. injection of 6 mg/kg or more in anesthetized dogs, accompanied by an increase in plasma histamine concentration. Both changes were markedly reduced when the test drug was administered by continuous i.v. infusion. 3. Autonomic nervous system: DR-3355 inhibited nictitating membrane contraction induced by both pre- and post-ganglionic stimulation, and inhibited the depressor response to acetylcholine at 20 mg/kg i.v. It had no influence on pupil size or on pressor response to norepinephrine. 4. Gastrointestinal system: DR-3355 at 600 mg/kg p.o. inhibited gastric secretion. Dog gastrointestinal motility was slightly inhibited, and was then stimulated over the dose range of 2-20 mg/kg i.v. It had no influence on gastrointestinal propulsion, the gastric emptying rate or the gastric mucosa. 5. Isolated smooth muscle: At a concentration of 5 x 10(-4) g/ml, DR-3355 was devoid of spasmogenic or smasmolytic activity, except for showing a slight relaxation effect (trachea), inhibition of nicotine-induced contraction (ileum) and spontaneous or oxytocin-induced motility (pregnant uterus). 6. Miscellaneous: DR-3355 inhibited the urine output and carrageenin-induced paw edema at 600 mg/kg p.o. It had no effect on skeletal muscle contraction or the corneal reflex.

Animals↗
PubMed1992

Isolation and characterization of alpha 1-acid glycoprotein from horses, and its evaluation as an acute-phase reactive protein in horses.

Equine alpha 1-acid glycoprotein (alpha 1AG) was isolated from equine serum by successive ammonium precipitation, anion- and cation-exchange chromatographies, and gel filtration. Purified equine alpha 1AG had a molecular weight of 46,000 +/- 1,000, and contained 31.4% carbohydrate. Gel isoelectric focusing revealed an isoelectric point range of 2.8 to 3.7. With immunoelectrophoresis, it was found that alpha 1AG migrated to the alpha 1-globulin region. Single radial immunodiffusion was used for quantitative measurement of alpha 1AG in equine serum. In clinically normal foals, serum alpha 1AG was undetectable (less than or equal to 20 micrograms/ml) in less than or equal to 7-day-old foals, but was detected by 14 days. The alpha 1AG concentration (mean +/- SD) increased to reach mean adult values of 99.23 +/- 26.90 micrograms/ml by 1 year of age. The alpha 1AG concentration in pregnant mares decreased at 2 to 3 months before parturition, then gradually increased until 1 day after parturition, when a brief decrease was observed. The concentration increased again at 2 weeks after foaling, then a decrease was observed, after which the alpha 1AG concentration increased again by 2 to 4 months after parturition. The concentration of serum alpha 1AG quickly rose to peak values 2 to 3 days after castration and jejunojejunostomy in adult horses, returning to baseline values by 14 to 28 days after surgery. The alpha 1AG was concluded to be an acute-phase reactive protein in horses.

Acute-Phase Reaction↗
PubMed1992

[Radiosensitive malignant meningioma presenting Garcin's syndrome: a case report].

A 58-year-old woman with Garcin's syndrome caused by malignant meningioma is reported. She first noticed left facial hypesthesia followed by left visual disturbance with exophthalmos. CT scan showed an enhanced mass extending from the left cavernous sinus to the left orbit. Cranial x-ray revealed bone deformity around the orbit. The tumor was subtotally resected and its histological type was shown to be anaplastic meningioma. After the initial surgery the patient was left with hyposmia, mild ptosis and incomplete 6th cranial nerve palsy on the left side. After one and half years, not only palsy of those cranial nerves but also that of other unilateral cranial nerves became progressively apparent due to tumor regrowth. In total, 11 nerves (2nd-12th) were affected by the tumor, without long tract signs or symptoms of increased intracranial pressure. Radiation therapy carried out after the 2nd surgery was extremely effective and resulted in the recovery of lower cranial nerve function. The tumor was founded to have disappeared completely on the 2-year follow-up CT.

Combined Modality Therapy↗
PubMed1991

Identity determinants of E. coli tryptophan tRNA.

The first base pair of the acceptor stem A1-U72 and the discriminator base G73, as well as the anticodon nucleotides, characterize the tryptophan tRNA in E. coli. To determine the contribution of these nucleotides to the tryptophan acceptor activity, various transcripts of E. coli tryptophan tRNA mutants were constructed. Substitutions of the discriminator base G73, which is conserved within prokaryotic tryptophan tRNAs, impaired aminoacylation with tryptophan. Substitutions of other purine-pyrimidine pairs for A1-U72 revealed that only U72 weakly contributed to recognition by tryptophanyl-tRNA synthetase. The E. coli aspartic acid tRNA transcript introducing the tryptophan anticodon CCA showed almost the same tryptophan charging activity as the tryptophan tRNA transcript possessing a G1-C72 base pair. Only a low activity was detected in the mutant tryptophan tRNA transcript possessing a set of G1-C72 and A73, which is observed in eukaryotic tryptophan tRNAs. These results indicate that the anticodon and G73 are major identity determinants of tryptophan tRNA in E. coli, whereas the A1-U72 base pair is only a weak recognition element.

Anticodon↗
PubMed1991

Inhibition of the first ovulation and ovarian prostaglandin F2 alpha metabolism by danazol in rats.

The present study was conducted to investigate the mode of action of danazol by monitoring the first ovulation, serum luteinizing hormone (LH) levels and ovarian prostaglandin (PG) F2 alpha metabolism in pregnant mare serum gonadotropin (PMSG)-primed immature female rats. When danazol (750 mg/kg) was given p.o. once a day for 5 days (day 24-28), the occurrence of the first ovulation, the increase in capacity to form 13,14-dihydro-PGF2 alpha and PGF2 alpha levels induced by PMSG (5 IU) injected on day 26 were clearly inhibited on day 29. Danazol also markedly suppressed the LH surge occurring on day 28. Although the danazol-induced blockage of ovulation was restored by injection of human chorionic gonadotropin, the number of oocytes was significantly decreased as compared with that of controls. The present data indicate that the inhibitory actions of danazol on ovulation and ovarian PGF2 alpha metabolism may occur via some direct effects on the ovary in addition to the suppression of gonadotropin release from the pituitary gland.

Animals↗
PubMed1991

[Effect of oxygen free radicals on the rat pancreas in vivo].

Many reports concerning the involvement of active oxygen free radicals in the pathogenesis and progression of acute pancreatitis have been published. In this study, the direct toxic effect of active oxygen free radicals on the rat pancreas was evaluated in vivo. Superoxide anions, generated via the xanthine/xanthine oxidase (X/XO) system, and hydrogen peroxide (H2O2) were used. After continuous arterial injection of X/XO into the celiac artery hemorrhage and extensive edema developed. However, additional continuous injection of superoxide dismutase (SOD) into the external jugular vein completely suppressed the hemorrhage and relieved the edema. When hydrogen peroxide (100 microM/Kg/hour) was injected continuously through the celiac artery made hemorrhage and edema were recognized in the pancreas, both of which were suppressed by continuous injection of catalase (10 mg/Kg/hour) or gabexate mesilate (10 mg/Kg/hour) into the external jugular vein. The amylase and lipase levels in the intraperitoneal fluid rose to more than 10 times the preoperative values 5 hours after drug administration. These levels were lowered to 2 times the preoperative values by the continuous venous injection of SOD or catalase (which are specific scavengers of superoxide anions or hydrogen peroxide, respectively) or by gabexate mesilate. On the other hand, serum amylase and lipase levels remained almost constant throughout the entire experiment. Thus, the administration of active oxygen free radicals caused acute pancreatitis, which was suppressed by the systemic administration of specific scavengers for each free radical. Active oxygen free radicals were shown to have a direct, toxic effect on the pancreas.

Acute Disease↗
PubMed1991

High pressure antagonism of alcohol effects on the main phase-transition temperature of phospholipid membranes: biphasic response.

The combined effects of high pressure (up to 300 bar) and a homologous series of 1-alkanols (ethanol C2 to 1-tridecanol C13) were studied on the main phase-transition temperature of dipalmitoylphosphatidylcholine (DPPC) vesicle membranes. It is known that short-chain alkanols depress and long-chain alkanols elevate the main transition temperature. The crossover from depression to elevation occurs at the carbon-chain length about C10-C12 in DPPC vesicle membranes coinciding with the cutoff chain-length where anesthetic potency suddenly disappears. Alkanols shorter than C8 linearly decreased the transition temperature and high pressure antagonized the temperature depression. Alkanols longer than C10 showed biphasic dose-response curves. High pressure enhanced the biphasic response. In addition, alkanols longer than the cutoff length depressed the transition temperature under high pressure at the low concentration range. These non-anesthetic alkanols may manifest anesthetic potency under high pressure. At higher concentrations, the temperature elevatory effect was accentuated by pressure. This biphasic effect of long-chain alkanols is not related to the 'interdigitation' associated with short-chain alkanols. The increment of the transition temperature by pressure was 0.0242 K bar-1 in the absence of alkanols. The volume change of the transition was estimated to be 27.7 cm3 mol-1. This value stayed constant to the limit of the present study of 300 bar.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1991

A statistical mechanical analysis of the effect of long-chain alcohols and high pressure upon the phase transition temperature of lipid bilayer membranes.

Long-chain n-alcohols decrease the main phase-transition temperature of lipid vesicle membranes at low concentrations but increase it at high concentrations. The nonlinear phenomenon is unrelated to the interdigitation and is analyzed by assuming that alcohols form solid solutions with solid as well as liquid phases. The biphasic response originates from the balance of the free energy difference of alcohols in the liquid and solid membranes (delta gA) and the alcohol-lipid interaction free energy difference (delta u) between the two phases. When delta gA less than 0 and delta u greater than 0, or delta gA less than delta u less than 0, the transition temperature decreases monotonously according to the increase in the alcohol concentration. When delta gA greater than 0 and delta u less than 0, or delta gA greater than delta u greater than 0, it increases monotonously. Biphasic response occurs with a minimum temperature when delta u greater than delta gA greater than 0, and with a maximum temperature when delta u less than delta gA less than 0. When the alcohol carbon-chain length becomes closer to the lipid carbon-chain length, delta u is equalized by delta gA, and the temperature minimum of the main transition is shifted to extremely low alcohol concentrations. Hence, long-chain alcohols predominantly elevate the main transition temperature and lose their anesthetic potency. High pressure decreased both delta gA and delta u. Presumably, high pressure improves the packing efficiency of liquid membranes and decreases the difference between the solid and liquid membrane properties.

Alcohols↗
PubMed1991

Intrapericardial OK-432 instillation for the management of malignant pericardial effusion.

Ten patients with malignant pericardial effusion were treated with intrapericardial injection of OK-432 (penicillin-treated and heat-treated lyophilized powder of the substrain of Streptococcus pyogenes A3). After intrapericardial insertion of a catheter, a maximal volume of pericardial fluid was withdrawn with cytologic confirmation of malignancy. Five or 10 Klinische Einheit (KE) (KE is a unit used to express the strength of a preparation) of OK-432 diluted in 20 ml of saline was injected into the pericardial space in seven and three patients, respectively. It was repeated in case of reaccumulation. Seven patients were treated only once and the remaining three required a second treatment. Complete control of pericardial effusion was achieved in all patients for an average of 329 days (range, 54 to 790 days). Fever and chest pain were experienced in six and five patients, respectively, but were controlled with antipyretics. Two of three patients who received 10 KE of OK-432 experienced hypotension that was successfully controlled with vasopressor drugs with or without reaspiration of pericardial fluid. Rapid reactive reaccumulation of the pericardial fluid was thought to be a cause of hypotension. A follow-up computed tomography (CT) scan was performed in seven patients and a thickened pericardium was noticed in five; no patients had constrictive pericarditis. These results suggest that intrapericardial administration of 5 KE of OK-432 is an effective and safe treatment for malignant pericardial effusion.

Adult↗
PubMed1991

Basic fibroblast growth factor in rat corpus luteum stimulates prostaglandin F2-alpha production.

Rat luteal cells (LC) were incubated with or without basic fibroblast growth factor (bFGF) in a serum-free medium. Prostaglandin F2 alpha (PGF2 alpha) production was stimulated in a dose-dependent manner at 0.03-1 ng/ml of bFGF. One ng/ml of bFGF caused approximately 5-fold the increment of PGF2 alpha at every stage of LC after 48 hrs of incubation. bFGF also raised progesterone secretion from LC, and this stimulatory effect on progesterone was more distinguishable in an early-, than a middle- and a late-stage. Additionally, bFGF concentration throughout the luteal phase was assessed using western blot analysis. The protein with typical molecular weight 18 kDa form was in high concentration throughout the luteal phase. These results suggest that bFGF may play a role in the regulation of PGF2 alpha and progesterone production as autocrine, but not in mitosis in corpus luteum.

Animals↗
PubMed1991

Identity determinants of E. coli tRNA(Val).

In order to study the identity elements of valine tRNA, various transcripts of E. coli valine tRNA mutants were constructed. Both mutations at the second letter A35 of the anticodon and at the discriminator base A73 seriously damaged valine charging activity. Mutations at either the G3-C70 or U4-A69 base pairs in the acceptor stem also affected the activity. Only one nucleotide substitution of the second letter G35 of the anticodon with A35 brought an 18% valine charging activity into alanine tRNA, which acquired an almost full charging activity with valine by introducing an additional change at those two base pairs in the acceptor stem. These results indicate that the second letter A35 of the anticodon, discriminator base and acceptor stem are involved in recognition by valyl-tRNA synthetase.

Base Composition↗
PubMed1991

Retinoic acid induces polarizing activity but is unlikely to be a morphogen in the chick limb bud.

Retinoic acid is a putative morphogen in limb formation in the chick and other vertebrates. In chick limb formation, it is thought that retinoic acid is released from the zone of polarizing activity (ZPA) and the concentration gradient of retinoic acid formed from the posterior to the anterior provides positional cues for digit formation. Implantation of a bead containing retinoic acid at the anterior margin of the limb bud induces a mirror-image symmetrical duplication of the digit pattern similar to that observed when the ZPA is grafted into the anterior margin of the host limb bud. Also, the level of endogenous retinoic acid (25 nM on average) is higher in the posterior one third of the limb bud. We found that when the bead containing either retinoic acid or an analogue but not the ZPA, was implanted in the anterior margin of the chick limb bud, expression of the retinoic acid receptor type-beta gene was induced around the bead within 4 h. These results indicate that exogenous retinoic acid is not identical with the ZPA morphogen. As the anterior tissue exposed to retinoic acid has polarizing activity, we conclude that the primary function of exogenous retinoic acid is to induce polarizing activity in the limb bud.

Amino Acid Sequence↗
PubMed1991

Brain stem auditory-evoked potentials in meningomyelocele. Natural history of Chiari II malformations.

Brain stem auditory-evoked potentials (BAEPs) were recorded in 30 patients with meningomyelocele and shunted hydrocephalus ranging in age from birth to 33 years. Twenty-two of them had Chiari II malformation, one of which was symptomatic. In 22 cases, including 15 with Chiari II malformation, BAEPs were recorded repeatedly after periods ranging from 18 months to 7 years. The results were as follows: (1) III-V interpeak latency (IPL) decreased progressively from prolonged to the normal range with growth until 25 years of age; (2) I-III IPL tended to prolong gradually from the normal range; (3) these findings may indicate that the natural history of Chiari II malformation is delayed maturation of the brain stem and intensification in the elongation and stretching of the hindbrain and lower cranial nerves.

Adolescent↗
PubMed1991

Study on suspended particulate matter and polycyclic aromatic hydrocarbons in indoor and outdoor air.

To study changes in the concentration of suspended particulate matter (SPM) in indoor and outdoor air, a new portable sampler (AND sampler) was designed that could separately collect particles exhibiting aerodynamic diameters of greater than 10 microns, 2-10 microns, and less than 2 microns. The relationship between the airborne particle concentration in indoor air and that in outdoor air varied with the aerodynamic diameter of the particles. The concentration of SPM in the indoor air increased in proportion to that in the outdoor air. The concentration of polycyclic aromatic hydrocarbons (PAH) in SPM also varied with the aerodynamic diameter of the particles. Fine particles exhibiting an aerodynamic diameter of less than 2 microns contained high concentration of PAH. The concentrations of benzo(k)fluoranthene, benzo(a)pyrene, and benzo(ghi)perylene in indoor air increased in proportion to those in outdoor air.

Air Pollutants↗