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Biomedical subjects

M Yoshida

Publications and source records attributed to M Yoshida.

At least 703 records · Page 39Linked to original sources
PubMed1999

[A case of stage IV esophageal cancer successfully treated by chemoradiation].

A 63-year-old man was admitted to our institution with a hard tumor on the left side of the neck. He was diagnosed as having advanced esophageal cancer (Stage IV) with a massive supraclavicular lymph node metastasis, and the lesion was thought to be unresectable. He was treated with chemotherapy (CDDP-VDS-5-FU) and radiation therapy, and all the tumors completely disappeared on endoscopic and CT examination. A stricture with scarring was detected in the esophagus at 6 months after treatment. No neoplastic tissue was detected in the lesion, and his dysphagia was relieved by dilation of the stricture. Recurrence on the left side of the neck was detected by CT at 2.5 years after chemoradiation therapy. However, the tumor has not grown over the 2-year interval since then, so it seems to be dormant. He has now survived with a good QOL for 5 years since the first hospital admission. We conclude that advanced esophageal cancer can be treated with chemoradiation therapy if the patient is in sufficiently good overall condition.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Infectious complications during remission induction therapy in 577 patients with acute myeloid leukemia in the Japan Adult Leukemia Study Group studies between 1987 and 1991.

The Japan Adult Leukemia Study Group analyzed infectious episodes in 577 patients with acute myeloid leukemia during remission induction therapy between 1987 and 1991. 542 patients (93.9%) experienced at least one infectious episode, 121 (21.0%) had microbiologically documented infection; there was clinically documented infection in 184 (31.9%) and unexplained fever in 237 (41.1%). Among 121 microbiologically documented infections, bacteremia/fungemia was observed in 68, pneumonia in 33, and other types of infections in 20. Among the bacteremia/fungemia, gram-negative bacteria accounted for 41.2% (Pseudomonas aeruginosa was the most common), gram-positive bacteria for 39.7%, fungi for 16.2% (Candida spp. being most frequent), and polymicrobial for 2.9%. The most frequent isolates among pneumonia were Pseudomonas aeruginosa and Aspergillus. A total of 70 patients (12.1%) died during remission induction. Mortality of 68 patients with bacteremia/fungemia was 26.5%; in these patients, mortality with concomitant pneumonia increased to 41.4%; without pneumonia, mortality was 15.4% (P < 0.05). Mortality according to the isolated microbes was 17.2% for gram-negative bacteria, 25% for gram-positive bacteria, and 54.5% for fungi. Mortality of 113 patients with pneumonia (33 microbiologically documented and 80 clinically documented), 20 with other microbiologically documented infections, 104 with other clinically documented infections, and 237 with unexplained fever was 25.7%, 5.0%, 5.8%, and 5.1%, respectively.

Acute Disease↗
PubMed1999

[The cerebral peduncle lesion in multiple system atrophy].

Atrophy of the cerebral peduncle and the pons can be seen on radiologic examination in patients of multiple system atrophy. This radiologic finding is one of the landmarks for the diagnosis of multiple system atrophy, but its detailed pathological background has not been thoroughly assessed. To clarify the pathological features of the cerebral peduncle lesion, samples from 28 autopsied cases (male 16, female 12; age 50-76 yr) were semiquantitatively examined after staining by HE, KB, Holzer, GFAP, Bodian and Gallyas methods. Atrophy of the cerebral peduncle was symmetric in most cases and resulted from the loss of small-sized nerve fibers. The glial cytoplasmic inclusion (GCI) in the cerebral peduncle increased significantly in severe atrophic cases compared with mild atrophic cases. However, in the most severe atrophic cases, in which this tissue was severely damaged, the GCI was decreased. The atrophy of the cerebral peduncle correlated significantly with the degree of degeneration in the olivo-ponto-cerebellar system and tended to correlate with a decrease in brain weight. The duration of disease is significantly longer in severe atrophic cases compared with mild atrophic cases.

Aged↗
PubMed1999

Evaluation of local platelet deposition during laser thermal angioplasty.

Laser thermal angioplasty is one of the brand-new transluminal interventions for arterial occlusive disease. And one of the most important prognostic factors of this intervention is the degree of local platelet deposition which causes the acute platelet thrombus and increases the proliferation of smooth muscle cells. The purpose of this study is to assess the degree of platelet deposition on the laser ablated area and to investigate the optimal conditions of laser ablation from the point of thrombogenesis. First of all, the laser ablations of various delivered energy were carried out on canine femoral arteries, then thrombus formation after laser ablation was evaluated with angioscopy. No thrombus was recognized on all ablated areas in the cases with a laser energy of 16 Joule (J) and 20 J. On the other hand, small thrombus on the ablated area was observed in 1 of 4 cases (25%) with that of 24 J, and in 2 of 4 cases (50%) with that of 30 J. Then, the degree of platelet deposition on the laser ablated area was evaluated with platelet labeled radioimmunoassay. Laser ablations were employed in canine femoral arteries varying delivered laser energy. There were no differences in the numbers of platelet deposition when the laser energy for one shot was within 24 J. The numbers of platelet deposition with a laser energy of 30 J and 45 J were significantly (p < 0.05) higher than those with a laser energy within 24 J. The numbers of platelet deposition were gradually increased related to the frequency of laser ablations, and the numbers of platelet depositions in 10 repeated laser ablations of 16 J and 20 J were significantly (p < 0.05) higher than that in single laser ablation of 16 J and 20 J. From the aspect of local platelet deposition, the optimal laser energy for one shot should be restricted within 24 J and the repeated ablation was the most appropriate method of laser thermal ablation.

Aluminum↗
PubMed1999

The first report on human cases serologically diagnosed as Japanese encephalitis in Indonesia.

Although Japanese encephalitis (JE) virus was isolated from mosquitos in 1974, human JE cases have never been reported in Indonesia in spite of the prevalence of anti-JE antibodies among human and pig populations as well as abundant JE vector mosquitos. In this report, we describe serological diagnosis of JE cases in Bali. Indonesia. using IgM-capture ELISA both on serum and cerebrospinal fluid (CSF) of the patients. In the first series of our investigation (Series 1), we examined serum specimens from 12 patients with clinical diagnosis of viral encephalitis, meningitis or dengue hemorrhagic fever (DHF), and found 2 possible JE cases. In the next series (Series 2), we examined both serum and CSF from encephalitis patients and gave laboratory diagnosis of JE. One of them was suspected to have concomitant or recent infection with dengue virus, probably type 3. These results strongly indicated that JE has been prevalent in Bali, Indonesia.

Child, Preschool↗
PubMed1999

Laparoscopic ultrasonography and operative cholangiography prevent residual common bile duct stones in laparoscopic cholecystectomy.

We retrospectively evaluated the role of intraoperative cholangiography (IOC) combined with laparoscopic intraoperative ultrasonography (LIOU) for detection of common bile duct (CBD) stones in patients undergoing laparoscopic cholecystectomy. We reviewed 184 patients with biliary stones. Preoperatively, all patients underwent ultrasonography (US); 183 of the patients were investigated by cholangiography (oral and intravenous cholangiography in 145 and endoscopic retrograde cholangiography in 44). LIOU was carried out in all patients and IOC was done in 183. LIOU visualized the bile duct in 94.6% of the patients and IOC was successful in 95.6%. CBD stones were detected in a total of 17 patients, 9 (52.9%) of whom were positive on preoperative investigations. The sensitivity for detecting CBD stones was 29.4% with US, 22.2% with oral and intravenous cholangiography, 50.0% with endoscopic retrograde cholangiography, 82.4% with LIOU, and 93.3% with IOC. The diameter of the stones visualized intraoperatively (4.4 +/- 1.2 mm) was smaller than that of the stones detected preoperatively (6.9 +/- 2.6 mm). The stones were removed during laparoscopy in 15 patients and after conversion to laparotomy in 2. None of the patients had residual CBD stones after follow-up for 6 to 50 months. Intraoperative examination using both LIOU and IOC was useful for prevention of residual CBD stones.

Adult↗
PubMed1998

The Dictyostelium developmental cDNA project: generation and analysis of expressed sequence tags from the first-finger stage of development.

In an effort to identify and characterize genes expressed during multicellular development ill Dictyostelium, we have undertaken a cDNA sequencing project. Using size-fractionated subsets of cDNA from the first finger stage, two sets of gridded libraries were constructed for cDNA sequencing. One, library S, consisting of 9984 clones, carries relatively short inserts, and the other, library L, which consists of 8448 clones, has longer inserts. We sequenced all the selected clones in library S from their 3'-ends, and this generated 3093 non-redundant, expressed sequence tags (ESTs). Among them, 246 ESTs hit known Dictyostelium genes and 910 showed significant similarity to genes of Dictyostelium and other organisms. For library L, 1132 clones were randomly sequenced and 471 non-redundant ESTs were obtained. In combination, the ESTs from the two libraries represent approximately 40% of genes expressed in late development, assuming that the non-redundant ESTs correspond to independent genes. They will provide a useful resource for investigating the genetic networks that regulate multicellular development of this organism.

Animals↗
PubMed1998

Inhibitory effects of uterine endometrial carcinogenesis in Donryu rats by tamoxifen.

The effects of tamoxifen (TAM) on uterine carcinogenesis were investigated in female Donryu rats. The effects were initiated by a single intrauterine treatment with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) at a dose of 20 mg/kg body weight via the vagina at 10 weeks of age. TAM tubes (cholesterol tubes containing 50% TAM) were implanted into the backs of the rats for 13 months (full TAM group) or for the second-half of this period (half TAM group). In the control group treated with ENNG alone, various proliferative lesions were induced in the uterine endometrium and the incidence of endometrial adenocarcinomas was about 30%. In contrast, the uteri in both TAM-treated groups showed severe atrophy and the incidences of uterine proliferative lesions were limited to a few endometrial hyperplasias in the half TAM group. Most of the vaginas in both TAM-treated groups showed mucification, while cornification was common in the vaginal epithelium of controls. The ovaries demonstrated similar atrophy with cystic follicles and no corpora lutea in all groups. Other estrogen responsive endocrine organs, such as the pituitaries and adrenals, were small in the TAM-treated groups. Serum estrogen levels in the TAM-treated groups were lower than in the control group but progesterone levels did not differ. These results indicated that TAM acts as an anti-estrogen on the adult rat uterus, inhibiting the development of endometrial adenocarcinomas initiated by ENNG.

Adrenal Glands↗
PubMed1998

A phosphatidylinositol 3-kinase inhibitor wortmannin induces radioresistant DNA synthesis and sensitizes cells to bleomycin and ionizing radiation.

ATM and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) have been shown to have sequences homologous to the catalytic domains of mammalian phosphatidylinositol 3-kinase (PI3-kinase). In order to determine the contribution of ATM and DNA-PKcs to the increased sensitivity of cells to DNA-damaging agents observed in the presence of PI3-kinase inhibitors, we examined the effects of a PI3-kinase inhibitor, wortmannin, on cellular sensitivity to bleomycin (BLM), mitomycin C (MMC), X-irradiation and ultraviolet (UV)-irradiation using 2 human tumor cell lines (T98G and A172), a human fibroblast cell line (LM217), an ataxia telangiectasia (AT) cell line (AT3BISV), a scid murine cell line (SCF) and a control murine cell line (CBF). Wortmannin sensitized all of the cells, including AT3BISV and SCF, to BLM and X-irradiation, but not to MMC or UV-irradiation. Hypersensitivity to BLM and X-irradiation and normal sensitivity to MMC and UV-irradiation are characteristic phenotypes of both AT and scid mice. DNA-dependent protein kinase (DNA-PK) activity was suppressed by wortmannin to 45-65% of the control values in all of the cells except SCF, in which DNA-PK activity was not detected. Wortmannin also induced radioresistant DNA synthesis, which is a cellular phenotype of AT, in T98G and SCF cells, but did not change the DNA synthesis rates after X-irradiation in AT3BISV. Our data suggest that wortmannin decreases the activities of both the ATM protein and DNA-PK, indicating that it might be of use as a sensitizing agent for radiotherapy and chemotherapy.

Androstadienes↗
PubMed1998

Behavioral recovery in 6-hydroxydopamine-lesioned rats by cotransduction of striatum with tyrosine hydroxylase and aromatic L-amino acid decarboxylase genes using two separate adeno-associated virus vectors.

Parkinson's disease (PD) is characterized by the progressive loss of the dopaminergic neurons in the substantia nigra and a severe decrease in dopamine in the striatum. A promising approach to the gene therapy of PD is intrastriatal expression of enzymes in the biosynthetic pathway for dopamine. Tyrosine hydroxylase (TH) catalyzes the synthesis of L-dopa, which must be converted to dopamine by aromatic L-amino acid decarboxylase (AADC). Since the endogenous AADC activity in the striatum is considered to be low, coexpression of both TH and AADC in the same striatal cells would increase the dopamine production and thereby augment the therapeutic effects. In the present study, the TH gene and also the AADC gene were simultaneously transduced into rat striatal cells, using two separate adeno-associated virus (AAV) vectors, AAV-TH and AAV-AADC. Immunostaining showed that TH and AADC were coexpressed efficiently in the same striatal cells in vitro and in vivo. Moreover, cotransduction with these two AAV vectors resulted in more effective dopamine production and more remarkable behavioral recovery in 6-hydroxydopamine (6-OHDA)-lesioned rats, compared with rats receiving AAV-TH alone (p < 0.01). These findings suggest an alternative strategy for gene therapy of PD and indicate that the simultaneous transduction with two AAV vectors can extend their utility for potential gene therapy applications.

Animals↗
PubMed1998

Central circuits controlling locomotion in young frog tadpoles.

The young Xenopus tadpole is a very simple vertebrate that can swim. We have examined its behavior and neuroanatomy, and used immobilized tadpoles to study the initiation, production, coordination, and termination of the swimming motor pattern. We will outline the sensory pathways that control swimming behavior and the mainly spinal circuits that produce the underlying motor output. Our recent work has analyzed the glycinergic, glutamatergic, cholinergic, and electrotonic synaptic input to spinal neurons during swimming. This has led us to study the nonlinear summation of excitatory synaptic inputs to small neurons. We then analyzed the different components of excitation during swimming to ask which components control frequency, and to map the longitudinal distribution of the components along the spinal cord. The central axonal projection patterns of spinal interneurons and motoneurons have been defined in order to try to account for the longitudinal distribution of synaptic drive during swimming.

Animals↗
PubMed1998

Human asparaginyl-tRNA synthetase: molecular cloning and the inference of the evolutionary history of Asx-tRNA synthetase family.

We have cloned and sequenced a cDNA encoding human cytoplasmic asparaginyl-tRNA synthetase (AsnRS). The N-terminal appended domain of 112 amino acid represents the signature sequence for the eukaryotic AsnRS and is absent from archaebacterial or eubacterial enzymes. The canonical ortholog for AsnRS is absent from most archaebacterial and some eubacterial genomes, indicating that in those organisms, formation of asparaginyl-tRNA is independent of the enzyme. The high degree of sequence conservation among asparaginyl- and aspartyl-tRNA synthetases (AsxRS) made it possible to infer the evolutionary paths of the two enzymes. The data show the neighbor relationship between AsnRS and eubacterial aspartyl-tRNA synthetase, and support the occurrence of AsnRS early in the course of evolution, which is in contrast to the proposed late occurrence of glutaminyl-tRNA synthetase.

Amino Acid Sequence↗
PubMed1998

Indication and clinical results of laminoplasty for cervical myelopathy caused by disc herniation with developmental canal stenosis.

STUDY DESIGN: The outcome of a herniated disc in patients with cervical myelopathy treated by laminoplasty without discectomy and in those treated conservatively was studied by magnetic resonance imaging. OBJECTIVES: To compare the surgical results of laminoplasty with those of anterior spinal fusion in patients with myelopathy caused by to cervical disc herniation and to make a treatment strategy for cervical disc herniation depending on these results. SUMMARY OF BACKGROUND DATA: Anterior discectomy and spinal fusion have had acceptable surgical results, but many complications have been reported, especially adjacent segment degeneration and bone graft complications. METHODS: Forty-seven patients with cervical disc herniation were examined in this study. Of them, 32 patients (mean age, 56 years) underwent laminoplasty without resection of the herniated disc. Seven patients with mild cervical myelopathy and 8 patients with radiculopathy (mean age, 53 years) were treated conservatively. As a control group, 44 patients (mean age, 50.3 years) who underwent anterior spinal fusion were examined. All patients in the laminoplasty group also had congenital spinal canal stenosis in which the ventrodorsal canal diameter was less than 13 mm. The association between the outcome of a herniated disc and clinical features was investigated. The severity of myelopathy was evaluated according to the Japanese Orthopaedic Association's scoring system. Surgical outcomes were evaluated by the system of Hirabayashi for determining recovery rate. RESULTS: The recovery rate averaged 67.9% in laminoplasty and 68.8% in anterior spinal fusion. There were no significant differences between the groups. No patients underwent anterior spinal fusion after laminoplasty. Follow-up magnetic resonance imaging showed regression of the size of the herniated disc in 15 of the 20 patients in the laminoplasty group and in 12 of 15 patients treated conservatively. In the MRI studies of the natural course of disc herniation, the size of the herniated disc decreased to almost half in 1 to 2 months and almost disappeared within 3 months after surgery. CONCLUSIONS: The size of the herniated disc in cervical lesions regressed as it does in the lumbar lesions. Laminoplasty for patients with narrowed spinal canals showed favorable surgical results. Therefore, the therapeutic method for cervical disc herniation should be chosen after taking the natural history of the disc herniation into consideration.

Case-Control Studies↗
PubMed1998

Axon projections of reciprocal inhibitory interneurons in the spinal cord of young Xenopus tadpoles and implications for the pattern of inhibition during swimming and struggling.

We have examined the morphology and longitudinal axon projections of a population of spinal commissural interneurons in young Xenopus tadpoles. We aimed to define how the distribution of axons of the whole population constrains the longitudinal distribution of the inhibition they mediate. Forty-three neurons at different positions were filled intracellularly with biocytin and processed with avidin-conjugated horseradish peroxidase. Soma size did not vary longitudinally and only one ipsilateral axon was found. Contralateral axons ascended, descended, or usually branched to do both. Total axon length and the extent of dendritic arborisation decreased caudally. The distributions of ascending and descending axon lengths were different; there were more long ascending (mean 737 +/- standard deviation 365 microm) than long descending (447 +/- 431 microm) axons. We used the axon length distribution data with existing data on the distribution of commissural interneuron somata to calculate the overall longitudinal density of these inhibitory axons. Axon numbers showed a clear rostrocaudal gradient. Axon length distributions were then incorporated into a simple spatiotemporal model of the forms of inhibition during swimming and struggling motor patterns. The model predicts that the peak of inhibition on each cycle will decrease from head to tail in both motor patterns, a feature already confirmed physiologically for swimming. It also supports a previous proposal that ascending inhibition during struggling shortens cycle period by shortening rostral motor bursts, whereas descending inhibition could delay subsequent burst onset.

Animals↗
PubMed1998

Role of two series of Ca2+ oscillations in activation of ascidian eggs.

Changes in [Ca2+]i are an essential factor regulating egg activation. Matured ascidian eggs are arrested at metaphase I, and two series of [Ca2+]i transients have been observed after fertilization: Ca2+ waves just after fertilization (Series I) and [Ca2+]i oscillation between the first and second polar body extrusion (Series II). We investigated mechanisms involved in the elevation of [Ca2+]i and the role of the [Ca2+]i transients during egg activation in Ciona savignyi. The monoclonal antibody 18A10 against IP3 receptor type 1, which inhibits IP3-induced Ca2+ release in hamster and mouse eggs, did not show substantial inhibitory effects on series I or egg deformation, whereas Series II and the first cell division were inhibited by the antibody. Ruthenium red, an inhibitor of ryanodine receptor-mediated Ca2+ release, had no apparent effect of [Ca2+]i transients and other events related to the egg activation. Microinjection of IP3 into unfertilized eggs induced [Ca2+]i transients similar to those seen in Series I, whereas injection of cyclic ADP ribose, an agonist of ryanodine receptors, rarely induced [Ca2+]i transient. Adenophostin B, a potent nonmetabolizable agonist of IP3 receptors, induced [Ca2+]i oscillations which continued after first polar body extrusion, without separation to two series, and led to extrusion of first and second polar bodies. These results suggest that Series II is driven by the mouse type 1-like IP3 receptor while Series I seems to be mediated by another type of IP3 receptor. Injection of IP3 only induced the first polar body extrusion and the egg was arrested at metaphase II even when a higher amount of IP3 was injected. On the other hand, reinjection of IP3 after the first polar body extrusion led to emission of the second polar body. Thus, Series I and II of [Ca2+]i transients are likely to be required for metaphase-anaphase transition in meiosis.

Adenosine↗
PubMed1998

Renal effects of endothelin in anesthetized rabbits.

Intrarenal arterial infusion of endothelin-1 (1, 3 and 10 ng/kg per min) reduced renal blood flow, urine flow rate and urinary Na+ excretion without affecting fractional Na+ excretion in anesthetized rabbits. An endothelin ET(A) receptor antagonist (R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]amino-4-me thyl-pentanoyl]amino-3-[3-(1-methyl-1H-indolyl)]propionyl]amino-3-(2-pyr idyl)propionic acid (FR139317, 1 microg/kg per min) attenuated the endothelin-1 (1 ng/kg per min)-induced renal responses. An endothelin ET(B) receptor antagonist N-cis 2,6-dimetylpiperidinocarbonyl-L-gamma-metylleucyl-D-1-met hoxycarbonyltryptophanyl-D-norleucine (BQ-788, 1 microg/kg per min) potentiated the endothelin-1-induced changes in renal blood flow, urine flow rate and urinary Na+ excretion. A nitric oxide (NO) synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME, 50 microg/kg per min) also potentiated the endothelin-1-induced reductions in urine flow rate and urinary Na+ excretion but not the reduction in renal blood flow. Endothelin-1 reduced fractional Na+ excretion in the presence of BQ-788 or L-NAME. A spontaneous NO donor 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene (30 ng/kg per min) slightly attenuated the antinatriuresis but not the vasoconstriction induced by endothelin-1. These results suggest that in the rabbit kidney in vivo endothelin ET(A) receptors mediate endothelin-1-evoked vasoconstriction and tubular Na+ reabsorption, that the concomitant stimulation of endothelin ET(B) receptors by endothelin-1 counteracts both the ET(A) receptor-mediated vascular and tubular actions, and that the tubular action, but not the vascular action, of endothelin-1 is also susceptible to changes in renal NO level.

Analysis of Variance↗
PubMed1998

Rapid detection of dihydrocodeine by thermospray mass spectrometry.

Rapid assay of dihydrocodeine (DHC) by thermospray mass spectrometry is explored. Liquid-liquid extractions of blood, urine and gastric contents were injected into a thermospray mass spectrometer, to which there was no column connected, and DHC was assayed by the flow injection method. The mass spectra of DHC under thermospray ionization and filament-on ionization modes consist of the MH+ ion of mlz 302 alone, which was clearly detected in the samples. Although DHC should be quantitated by gas chromatography-mass spectrometry, this method is applicable for rapid identification of DHC in biological materials.

Codeine↗