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Biomedical subjects

Y Hirano

Publications and source records attributed to Y Hirano.

At least 109 records · Page 6Linked to original sources
PubMed1998

Recurrent aciclovir-resistant herpes simplex in a child with Wiskott-Aldrich syndrome.

A boy with Wiskott-Aldrich syndrome suffered from thymidine kinase (TK)-altered and aciclovir-resistant herpes simplex virus type 1 (HSV-1) skin infections. He presented with severe herpes simplex around the left eye in March 1993 at the age of 8 years. HSV-1 strain TAS was isolated and was shown to be susceptible to aciclovir (50% inhibitory concentration (IC50) 0.23 microg/mL). He was treated with intravenous (i.v.) high dose aciclovir, 2 mg/kg per h, which produced an improvement. About 1 year later (May 1994), a severe herpes simplex infection appeared on his face, arm, genitalia, back and foot. Treatment with i.v. aciclovir, 2 mg/kg per h, was initiated, but the skin lesions did not improve. HSV-1 strain TAR was isolated and was shown to be resistant to aciclovir (IC50 36 microg/mL). HSV-1 TAR and TAS were susceptible to vidarabine (IC50 4. 4 and 2.9 microg/mL, respectively). The skin lesions were treated with i.v. vidarabine, 15-20 mg/kg per day, and healed satisfactorily. However, in March 1995, the patient again experienced a severe herpes simplex infection around the left eye. HSV-1 strain R95 was isolated and was shown to be resistant to aciclovir (IC50 36 microg/mL). Diminished sensitivity of HSV-1 TAR and R95 to aciclovir was associated with reduced viral TK activity and loss of aciclovir phosphorylation activity.

Acyclovir↗
PubMed1998

Denture mobility with six degrees of freedom during function.

The purpose of this study was (1) to assemble and verify a system to measure the three-dimensional (3-D) movement of the upper and lower complete dentures and the movement of the mandible simultaneously, and (2) to analyse the relation between denture movements and the path of closure of the mandible during function. A 3-D motion capture system with four infrared TV cameras was used for this purpose. The relation between the dentures and the mandibular movements was analysed through the change of the inner product of normal vectors of the denture occlusal planes and mandibular planes. The mandibular movements were classified into two types; the normal stroke (the path of closure was on the ipsilateral side of mastication) and the reverse stroke (on the contralateral side). The results showed that the system could measure the denture mobility within a 0.3 mm error. The mobility of the upper dentures had a correlation to the path of closure of the mandible regardless of the working side or nonworking side, and the lower dentures had a tendency to move toward the working side.

Aged↗
PubMed1998

[A patient with Streptococcus intermedius brain abscess treated with high dose penicillin G--susceptibility of the isolate to penicillin G and the concentration of penicillin G in cerebrospinal fluid].

We report here a 2-year-old boy with a Streptococcus intermedius brain abscess and bilateral ventriculitis successfully treated with a high dose penicillin G (200,000 U/kg/dose, 6 times a day, 1 hour continuous infusion). Although hydrocephalus residuced, the high dose penicillin G therapy cured his brain abscess and bilateral ventriculitis. The minimal inhibitory concentration of penicillin G to the isolate was 0.008 microgram/ml. The penicillin G concentration in the cerebrospinal fluid after 2 hours from the infusion was about 5 micrograms/ml. S. intermedius must be considered as one of the causative agents for brain abscess. High dose penicillin G therapy is one choice of treatment for brain abscess due to penicillin-susceptible streptococci.

Brain Abscess↗
PubMed1998

Functional interference of Sp1 and NF-kappaB through the same DNA binding site.

Gene activation by NF-kappaB/Rel transcription factors is modulated by synergistic or antagonistic interactions with other promoter-bound transcription factors. For example, Sp1 sites are often found in NF-kappaB-regulated genes, and Sp1 can activate certain promoters in synergism with NF-kappaB through nonoverlapping binding sites. Here we report that Sp1 acts directly through a subset of NF-kappaB binding sites. The DNA binding affinity of Sp1 to these NF-kappaB sites, as determined by their relative dissociation constants and their relative efficiencies as competitor DNAs or as binding site probes, is in the order of that for a consensus GC box Sp1 site. In contrast, NF-kappaB does not bind to a GC box Sp1 site. Sp1 can activate transcription through immunoglobulin kappa-chain enhancer or P-selectin promoter NF-kappaB sites. p50 homodimers replace Sp1 from the P-selectin promoter by binding site competition and thereby either inhibit basal Sp1-driven expression or, in concert with Bcl-3, stimulate expression. The interaction of Sp1 with NF-kappaB sites thus provides a means to keep an elevated basal expression of NF-kappaB-dependent genes in the absence of activated nuclear NF-kappaB/Rel.

Animals↗
PubMed1998

Structures of P-type transporting ATPases and chromosomal locations of their genes.

P-type ATPases (E1E2-ATPases) are primary active transporters which form phospho-intermediates during their catalytic cycle. They are classified into P1 to P4 based on the primary structure and potential transmembrane segments. Although the classic P-type ATPases are cation transporters, two new members have recently been found; one is a flippase catalyzing the flip-flop movement of aminophospholipids, but the substrate and function of the other one remain unknown. It would be interesting to determine whether the cations and aminophospholipids are transported by similar or different mechanisms. P-type ATPases are believed to have been derived from a common ancestor, and their genes are found to be distributed in various chromosomal loci. However, gene duplication events can be traced from the tandem arrangement of genes and their linkage map. Na+/K+- and H+/K+-ATPases have not only closely related a subunits but also similar beta subunits. Renal Na+/K+-ATPase has an additional subunit gamma. Similar small polypeptides (phospholemman, Mat-8 and CHIF), which induce Cl- and K+ currents, have been found. The idea of their functional and structural coupling with P-type ATPases, especially with H+/K+-ATPase, is intriguing. Each P-type ATPase must have specific domains or sequences for its intracellular trafficking (sorting, retention and recycling). Identification of such regions and studies on the molecules playing role in their recognition may facilitate the unveiling of various cellular processes regulated by P-type ATPases.

Adenosine Triphosphatases↗
PubMed1998

[The effects of YM26818: 1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl)urea and derivatives on pulmonary surfactant secretion and lung compliance].

To discover a novel compound which has an effect on pulmonary surfactant (PS) secretion, we studied the effects of various compounds on PS secretion by measuring the contents of PS in the bronchoalveolar lavage (BAL) fluid in guinea pigs. In the chemical modification study of ambroxol, which is known as a PS secretagogue, and a compound we discovered from our compounds library, 1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl)urea: YM-26818 (the increasing effect on PS in BALF, 34.7% at 50 mg/kg, i.p.). In the surfactant deficient model induced by BAL in guinea pigs, YM-26818 (5 and 10 mg/kg, p.o.) significantly increased the contents of PS in the BAL fluid compared with that of control animals (5 mg/kg: 60.3 +/- 8.0, 10 mg/kg: 59.4 +/- 4.3% increase). Concomitantly by these effects, the recovery of lung compliance was observed in this model (AUC of lung volume, control: 560 +/- 15, YM-26818 5 mg/kg: 898 +/- 51, YM-2681 10 mg/kg: 956 +/- 11 ml.min). These results may indicate that YM-26818 is useful for the therapy of adult respiratory distress syndrome (ARDS) and obstructive pulmonary diseases.

Animals↗
PubMed1998

Citrate promotes attachment of Prevotella nigrescens (intermedia) ATCC 25261 to hydroxyapatite.

Large quantities of Prevotella nigrescens (intermedia) ATCC 25261 (P. nigrescens) cells adhere to hydroxyapatite (HA) treated with citrate, but do not adhere experimental pellicle prepared from human whole saliva. To determine the nature of the citrate responsible for promoting P. nigrescens cell adhesion, the duration and frequency of citrate treatment of HA and the inhibitory effect of other carboxylates were tested. The citrate rapidly adhered to HA beads in less than 15 min. With a lower concentration (0.4 mM) of citrate, four treatments of HA were required to promote the maximum adherence to P. nigrescens cells. Citrate-enhanced P. nigrescens cell adherence to HA beads was also inhibited in the presence of cis-aconitate, oxaloacetate and oxalsuccinate. It was also found that P. nigrescens cells heated to 65 degrees C or higher for 5 min could no longer become attached to citrate-treated HA. These data suggest that citrate is one of the essential factors responsible for P. nigrescens cell attachment to apatitic surfaces, and that P. nigrescens' adhesion to citrate is extremely heat-sensitive.

Aconitic Acid↗
PubMed1998

Therapeutic results of intra-arterial chemotherapy in patients with malignant glioma.

Thirty-three adult patients with anaplastic astrocytoma or glioblastoma multiforme, verified between 1990 and 1997, received postoperative intra-arterial ACNU chemotherapy and irradiation. Since our previous strategies to malignant gliomas had included intra-venous ACNU, the purpose of the present study is to evaluate the advantage of intra-arterial ACNU over its intra-venous counterpart as the historical control (37 patients). The median survival was 74.7 weeks for the former and 81.7 weeks for the latter. Although both groups were equivalent in survival, toxicity was less frequent in the intra-arterial group. Histopathological diagnosis, patient age and the Karnofsky's performance status related well with the survival.

Adult↗
PubMed1998

[Association of bone mineral density with vitamin D receptor gene polymorphism--changes in radial bone mineral density with long-term follow-up: longitudinal study].

Recent studies have shown that genetic effects on bone mineral density (BMD) and bone turnover are related to vitamin D receptor (VDR) gene polymorphism. However, discordant studies have been published and it is still not clear whether VDR genotypes influence bone mass accretion and/or postmenopausal bone loss. To assess allelic influence of the VDR gene on BMD, we determined changes in 1/6-radial-BMD by several repeat measurements in the same subjects for about ten years and analyzed VDR polymorphism of BsmI restriction enzyme in 53 normal healthy Japanese women (age: 50.3 +/- 4.7 years, mean +/- SD). Twenty-seven (age: 53.2 +/- 4.7 years) of the subjects were post-menopausal (POST group). Among these 53 subjects, the distribution of bb, Bb and BB genotypes was 64.2%, 34% and 1.9%, respectively. The genotype frequencies in this study were very similar to those in previous reports concerning other Japanese women. There was no difference between the b group (women with bb genotype) and B group (women with BB or Bb genotype) in age, body weight, height, body mass index (BMI), years since menopause, serum osteocalcin and serum alkaline phosphatase values. In the POST group, BMD of the B group at menopause was lower than that of the b group (p < 0.05). About ten years after menopause, BMD did not differ significantly between these groups because the decrease in BMD in the b group was larger than that in the B group. Regarding changes in BMD in the POST group for four years after menopause, BMD of the b group was significantly decreased compared with the B group (p < 0.01). Our findings suggest that the differences in BMD by VDR genotype were larger among pre- and pri-menopausal women and seemed to decrease with years after menopause. It is suggested that there are other factors influencing BMD and postmenopausal bone loss in elderly women.

Bone Density↗
PubMed1997

Group II phospholipase A2 is increased in peritoneal and pleural effusions in patients with various types of cancer.

Serum levels of group II phospholipase A2 (PLA2) have been reported to be associated with stage of disease in cancer patients. These levels are also related to the malignant potential in tissues, and are an important prognostic factor. We radioimmunoassayed group II PLA2 levels in pleural and peritoneal effusions from patients with various cancers. We also investigated the production of group II PLA2 in cells in effusions from cancer patients by Northern blotting, immunocytochemistry and in situ hybridization. Immunoreactive group II PLA2 levels were significantly higher in effusions from 47 patients with various cancers, compared with those in sera and cirrhotic ascites. There was no significant correlation between group II PLA2 levels in effusions and those in sera. Group II PLA2 mRNA was expressed at a high level in cells from effusions, by Northern blot analysis, but not in those cells from blood. The localization of group II PLA2 protein and mRNA was intense in carcinoma cells and CD68-positive macrophages, determined by immunocytochemistry and in situ hybridization. In addition, IL-6 and IL-8 levels were significantly higher in effusions, in comparison with those in sera from patients, suggesting that cancer cells and macrophages produce group II PLA2 by IL-6. These group II PLA2 levels are apparently significantly increased in effusions, and the carcinoma cells and macrophages produce group II PLA2, as noted in effusions from patients with various cancers.

Adult↗
PubMed1997

Pharmacological analysis of the inflammatory exudate-induced histamine production in bone marrow cells.

The inflammatory exudate at the post-anaphylaxis phase of allergic inflammation in rats has an ability to enhance histamine production by bone marrow cells. To analyze the mechanism of the inflammatory exudate-induced histamine production pharmacologically, the effects of several drugs were examined in cultures of bone marrow cells. Incubation of the bone marrow cells in the presence of the inflammatory exudate that had been centrifuged and dialyzed against Hanks' balanced salt solution increased histidine decarboxylase activity in the cells and histamine concentration in the conditioned medium. The induction of histamine production by the inflammatory exudate was inhibited by actinomycin D (0.01-1 microM), an inhibitor of RNA synthesis, and cycloheximide (0.1-10 microM), a protein synthesis inhibitor. The protein kinase C inhibitors staurosporine (2-20 nM), K-252a (6-200 nM), and H-7 (10.3-103 microM) also inhibited the inflammatory exudate-induced histamine production in a concentration-dependent manner. The tyrosine kinase inhibitor genistein (3.7-37 microM) also inhibited the inflammatory exudate-induced histamine production, but the protein kinase A inhibitor H-89 (0.2 microM), and the adenylate cyclase activator forskolin (0.1 microM) showed no effect. These findings suggest that histamine production induced by the inflammatory exudate is mediated by the de novo synthesis of histidine decarboxylase and by the activation of protein kinase C and tyrosine kinase.

Anaphylaxis↗
PubMed1997

Multiple modulations of action potential duration by different calcium channel blocking agents in guinea pig ventricular myocytes.

Effects of extracellular applications of different types of Ca2+ channel blocking agents (Mn2+, verapamil, and nisoldipine) on action-potential duration and membrane currents were studied by the whole-cell patch-clamp technique in guinea pig ventricular myocytes. Low concentrations of Mn2+ (1 mM) and verapamil (1 microM) prolonged action-potential duration at 90% repolarization (APD90) with a suppressed plateau phase. Increases in Mn2+ (5 mM) and verapamil (5 microM) shortened APD90 with a further depression of the plateau. Nisoldipine (0.2-1 microM) shortened APD90 without lengthening it. Applications of Mn2+ and verapamil suppressed amplitudes of the L-type Ca2+ current (ICa), the delayed outward K+ current (IK), and the inward rectifier K+ current (IK1). Furthermore, the ratios of ICa:IK inhibition were similar by low and high concentrations of Mn2+ and verapamil. Nisoldipine selectively suppressed ICa without effect on IK and IK1. A low concentration (1 mM) of Mn2+ not only decreased the peak amplitude of ICa but also delayed its decay time course, which caused an increase in late ICa amplitude at the end of a 200-ms depolarizing pulse. Both verapamil and nisoldipine suppressed peak ICa without affecting its decay. Whereas Mn2+ suppressed IBa without changing its decay time course, verapamil and nisoldipine speeded up the IBa decay with suppressed amplitude of IBa. We conclude that different types of Ca2+ channel blocking agents (Mn2+, verapamil, and nisoldipine) diversely modulate APD because of their multiple modes of actions on ICa and IK.

Action Potentials↗
PubMed1997

Production of 5,8,11-Eicosatrienoic Acid (Mead Acid) by a (Delta)6 Desaturation Activity-Enhanced Mutant Derived from a (Delta)12 Desaturase-Defective Mutant of an Arachidonic Acid-Producing Fungus, Mortierella alpina 1S-4.

Enhanced production of 5,8,11-eicosatrienoic acid (Mead acid, 20:3(omega)9) was attained by a mutant fungus, Mortierella alpina M209-7, derived from (Delta)12 desaturase-defective M. alpina Mut48. The 20:3(omega)9 production by M209-7 was 1.3 times greater than that by its parent strain, Mut48. This is thought to be due to its enhanced (Delta)6 desaturation activity, which was 1.4 times higher than that of Mut48. In both strains, 87 to 88% of the total lipids comprised triacylglycerol (TG) and 85% of 20:3(omega)9 was contained in TG. On optimization of the culture conditions for M209-7, earlier glucose feeding and shifting of the growth temperature from 28 to 19(deg)C on the second day were shown to be effective. Under the optimal conditions with a 10-liter jar fermentor, 20:3(omega)9 production reached 1.65 g/liter of culture medium (corresponding to 118 mg/g of dry mycelia and 28.9% of total fatty acids), which is about twice that reported previously (0.8 g/liter).

Journal Article↗
PubMed1997

Stretch-induced enhancement of mechanical work production in frog single fibers and human muscle.

The relations between the velocity of prestretch and the mechanical energy liberated during the subsequent isovelocity release were studied in contractions of frog single fibers and human muscles. During isometric contractions of frog single fibers, a ramp stretch of varied velocity (amplitude, 0.02 fiber length; velocity, 0.08-1.0 fiber length/s) followed by a release (amplitude, 0.02 fiber length; velocity, 1.0 fiber length/s) was given, and the amount of work liberated during the release was measured. For human muscles, elbow flexions were performed with a prestretch of varied velocity (range, 40 degrees; velocity, 30-180 degrees/s) followed by an isokinetic shortening (velocity, 90 degrees/s). In both frog single fibers and human muscles, the work production increased with both the velocity of stretch and the peak of force attained before the release up to a certain level; thereafter it declined with the further increases of these variables. In human muscles, the enhancement of work production was not associated with a significant increase in integrated electromyogram. This suggests that changes in intrinsic mechanical properties of muscle fibers play an important role in the stretch-induced enhancement of work production.

Adult↗
PubMed1997

Stretch-induced enhancement of mechanical power output in human multijoint exercise with countermovement.

The relation between the eccentric force developed during a countermovement and the mechanical power output was studied in squatting exercises under nominally isotonic load (50% of 1-repetition maximum). The subjects (n = 5) performed squatting exercises with a countermovement at varied deceleration rates before lifting the load. The ground reaction force and video images were recorded to obtain the power output of the body. Net muscle moments acting at hip, knee, and ankle joints were calculated from video recordings by using inverse dynamics. When an intense deceleration was taken at the end of downward movement, large eccentric force was developed, and the mechanical power subsequently produced during the lifting movement was consistently larger than that produced without the countermovement. Both maximal and mean power outputs during concentric actions increased initially with the eccentric force, whereas they began to decline when the eccentric force exceeded approximately 1.4 times the sum of load and body weight. Video-image analysis showed that this characteristic relation was predominantly determined by the torque around the knee joint. Electromyographic analyses showed no consistent increase in time-averaged integrated electromyograph from vastus lateralis with the power output, suggesting that the enhancement of power output is primarily caused by the prestretch-induced improvement of an intrinsic force-generating capability of the agonist muscle.

Adult↗
PubMed1997

Ethanol sclerosis: one of the best treatments for thymic cyst in very elderly patients?

An 83-year-old female patient with a giant thymic cyst that was successfully treated by percutaneous aspiration and ethanol injection. The patient had complained of coughing and chest discomfort for several years. A chest X-ray film revealed the shadow of a large abnormal mass in the anterior mediastinum. We diagnosed it as a thymic cyst. The patient refused surgery because of her age. We chose a less invasive therapy, namely, ethanol sclerosis of the cyst. The cyst was successfully treated without any complications, and no recurrence was found at the one-year follow-up. This therapy may be one of the best treatments for thymic cysts, especially in very elderly patients.

Aged↗