Biomedical subjects

T Yazaki

Publications and source records attributed to T Yazaki.

At least 37 records · Page 2Linked to original sources

PubMed1998

[Imaging studies of excretory urography and computed tomography scan for patients suffering from renal colic].

Renal colic mainly due to urolithiasis is one of the most common morbid conditions in urology and commonly seen in the urology emergency clinic. Imaging studies were performed to evaluate the upper urinary tract of 29 patients suffering from renal colic in the 2 years between November, 1994 and October, 1996. After intramuscular injection of the analgesic (pentazocine, 15 mg), all 29 patients were examined by excretory urography (IVP) at the time of the first visit. In some patients abdominal plain computed tomography (CT) scan was performed consecutively even when extravasation of the contrast medium was not seen. Spontaneous peripelvic extravasation was seen in 14 patients (11 males and 3 females) with urolithiasis; 7 of them were diagnosed by IVP, 5 by IVP plus CT scan and 2 with CT scan only. IVP imaging study followed by plain abdominal CT scan is useful even when the contrast medium is not extravasated on IVP in patients suffering from renal colic.

Adult↗

PubMed1998

[A clinical study of superficial bladder cancer with grade 3 components].

A retrospective study was done on 33 patients treated for superficial bladder cancer, pTa and pT1, with grade 3 components between 1986 and 1995. All patients had undergone transurethral resection of the tumor (TUR-Bt), which was followed by total cystectomy in 7 patients. Three patients died of pulmonary diseases or heart attack and 6 patients subsequently died of bladder cancer. The 2-year and 5-year disease-specific survival rates of these patients were 83% and 75%, respectively, and the mean duration of follow-up was 50 months. Comparison of the disease-specific survival rates for several factors revealed that the configuration and size of the tumors were significantly predictable factors for prognosis. In well-selected patients with grade 3 superficial bladder cancer, bladder preservation seems to be possible by TUR with or without adjuvant therapies. Hence further studies on a larger series are needed to elucidate more feasible and reliable prognostic factors to avoid unnecessary cystectomy and improve the quality of life of the patients.

Adult↗

PubMed1998

[Clinical studies on the quality of life in patients with ileal conduit].

Between August, 1985 and December. 1995 ileal conduit was performed in 36 cases of bladder cancer (30 males, 6 females). A survey based on a questionnaire was carried out on 15 patients to assess their quality of life (QOL) after the surgery. The questionnaire dealt with the working situation, appetite, sleep, defecation, bathing, travel, general health condition, satisfaction, sexual life and erection. Although only 64.0% of the patients returned to work, appetite, hours of sleep and bathing frequency showed only a slight decrease. We performed total cystectomy without using the nerve sparing method. After the operation, three patients could have an erection and enjoy sexual life. Because the ileal conduit resulted in few complications and only a slight reduction in QOL, it was considered an appropriate operation.

Activities of Daily Living↗

PubMed1997

Multiple isoforms of neuregulin are expressed in developing rat dorsal root ganglia.

Accumulating evidence suggests that neuregulin (NRG) plays special roles in the development of the mammalian nervous system. We have already identified NRG as a survival factor for Schwann cells during development. In this report, we have studied all possible NRG isoforms and expression of NRG in the developing rat dorsal root ganglia (DRG) and compared them with those of brain and spinal cord. Neural NRG isoforms comprise common immunoglobulin and epidermal growth factor domains. Various different transcripts were characterized, which arose by alternative splicing in several regions: N-terminal (exon 1 or 2), spacer (exon 5), juxtamembrane (exon 9 or 10), and cytoplasmic (exon 12, 13, or 14) domains. At least 13 novel isoforms among 16 splice variants were identified. The transmembrane isoforms of NRG are dominant forms in developing rat DRG. The mRNA expression of NRG isoforms in DRG is similar to that in spinal cord, while in brain the expression is much less. The mRNA in DRG was found at similar levels from birth to postnatal day 7 of the premyelinating stage, and it decreased afterward. Our results suggest that several NRGs, including isoforms not reported before, play a role as survival factors for Schwann cells in the premyelinating stage.

Aging↗

PubMed1997

Subsite structure of the beta-glucosidase from Aspergillus niger, evaluated by steady-state kinetics with cello-oligosaccharides as substrates.

The beta-glucosidase from a commercially available preparation from Aspergillus niger was highly purified. The Michaelis constant Km and the molar activity K0 for cello-oligosaccharide substrates Gn (n = 2-6) were obtained by steady-state kinetic analysis on the beta-glucosidase-catalyzed hydrolysis at 25 degrees C and pH 5.0. Stoichiometric production of Gn-1 by the beta-glucosidase reaction for Gn was confirmed by HPLC techniques. Based on Km and K0 for Gn, subsite affinities (Ai, i = 1-6) were estimated as follows (kcal/mol): A1 = 1.3, A2 = 5.2, A3 = 0.65, A4 = -0.10, A5 = -0.65, and A6 = -0.26, of which A1-A3 are much higher than those of the beta-glucosidase of Candida wickerhamii. The subsite structure is quite similar to that of the alpha-glucosidase of A. niger, whereas the dependence of k0 on n is highly characteristic for beta-glucosidase, and decreases with n, suggesting some interaction between the particular subsites.

Aspergillus niger↗

PubMed1997

Immunohistochemical studies of proliferating cell nuclear antigen and cathepsin D in transitional cell carcinoma of the urinary bladder.

Immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and cathepsin D was performed on 60 transitional cell carcinoma (TCC) specimens from 60 patients with bladder cancer. The percentage of PCNA-positive cells (PCNA-labelling index) was determined by counting 500 or 1,000 cells, and cathepsin D expression was graded according to the extent of immunoreactivity to anti-cathepsin D antibody. The PCNA-labelling index was significantly higher in high-grade and high-stage tumors compared to that in low-grade and low-stage tumors. Cathepsin D was highly positive in grade-1 tumors. In contrast, 82% of grade-3 tumors and 76% of advanced tumors showed negative or low reactivity to anti-cathepsin D. Groups of high PCNA-labelling index and negative cathepsin D had significantly poorer prognoses compared to those of the low PCNA group and cathepsin D highly positive group, respectively, in univariate analyses. However, neither of these two factors were independent prognostic factors in multivariate analyses. These results suggest that the PCNA-labelling index and cathepsin D expression may indicate the malignant potential of TCC and may be able to provide additional information for predicting survival when stratifying for grade of bladder cancer.

Adult↗

PubMed1996

Expression of L1 in primary astrocytes via a defective herpes simplex virus vector promotes neurite outgrowth and neural cell migration.

The neural cell adhesion molecule L1 is a transmembrane glycoprotein of approximately 200 kDa molecular weight that is a member of the immunoglobulin super family. Multiple functions of L1 have been reported, including cell-cell interactions, neurite elongation, axonal fasciculation, cell migration, and myelination. L1 plays important roles in neural development and axonal regeneration in the peripheral nervous system (PNS), however, in the adult it is only present on neurons in the central nervous system (CNS). In the present study we have used defective herpes simplex virus (HSV) vectors to express full-length human or rat L1 in cultured primary rat cortical astrocytes. Rat cerebellar granule cells, a rather homogeneous population of neurons, co-cultured on a substrate layer of L1-expressing astrocytes demonstrated increased migration and neurite extension compared with neurons co-cultured on lacZ-expressing astrocytes of uninfected astrocytes. There was no detectable difference between human and rat L1. Because this vector system can be used to confer phenotypic changes in primary nervous system cells it will be useful for in vitro and in vivo studies of neural regenerative sprouting and plasticity in the CNS.

Animals↗

PubMed1996

Yearly variation of spontaneous somatic mutation frequency in the stamen hairs of Tradescantia clone KU 9 grown outdoors, which showed a significant increase after the Chernobyl accident.

Scoring of spontaneous somatic pink mutation frequency in the stamen hairs of Tradescantia clone KU 9, a heterozygote for flower color (blue/pink; the blue color being dominant), was carried out for 11 years on plants grown outdoors, during the period of May 11-31 (for 3 weeks) in every year from 1982 to 1992. Weekly and yearly variations of the spontaneous mutation frequency were observed, and such variations could mostly be correlated to the difference in temperature. That is, the mutation frequency was generally higher in the weeks and years when the temperature was relatively low, showing the strongest negative correlation with the average minimum temperature. The variations were also correlated to the diurnal temperature difference, the mutation frequency being higher with larger diurnal temperature difference in general. However, the mutation frequency observed in 1986 was exceptionally higher than that expected from the temperature for this year, and was very significantly higher than for other years. The scoring of mutation frequency was thus continued in 1986 for an additional 4 weeks (June 1-28), and it was confirmed that such higher mutation frequencies lasted for 6 weeks in total. The exceptionally high mutation frequency seemed to be related to the radioactive fallout which occurred in early to mid May of 1986, even in Japan, after the serious nuclear reactor accident at Chernobyl, and also to the biological concentrations of radioactive nuclides which subsequently occurred, although it was difficult to conclude this definitely. The mutation frequency in 1987 was second highest, and was also significantly higher than the lowest mutation frequency observed in 1990.

Climate↗

PubMed1996

Dose-dependent effects of oral acyclovir in the incubation period of varicella.

Dose of acyclovir (ACV) and clinical features of varicella were evaluated in 65 household contacts (0.8-9 y) who received oral ACV (5-80 mg/kg daily in four divided doses) during the latter half of the incubation period of varicella. The severity of the disease was compared with that of 23 children who did not receive ACV. Infection was confirmed by a fluorescent antibody to membrane antigen assay. The antibody titers and the rate of apparent infection increased as the dose of ACV administered decreased. The number of skin lesions in patients who received ACV was significantly reduced when compared to the control group. These data suggest dose-dependence of ACV for modification of varicella during secondary viremia in the incubation of the disease.

Acyclovir↗

PubMed1996

Treatment of glioblastoma U-87 by systemic administration of an antisense protein kinase C-alpha phosphorothioate oligodeoxynucleotide.

Glioblastoma multiforme is the most common form of malignant brain cancer in adults and, unfortunately, is not amenable to treatment with current therapeutic modalities. Human glioblastoma U-87 has many of the distinguishing phenotypic features of primary glioblastoma, including an autocrine form of proliferation, high levels of protein kinase C alpha (PKC alpha), and infiltration via white matter tracts. We show that treatment of mice bearing U-87 xenografts with an antisense phosphorothioate oligodeoxynucleotide (S-oligodeoxynucleotide) against the 3'-untranslated region of PKC alpha mRNA results in suppression of tumor growth. Growth was inhibited in both subcutaneous and intracranial tumors, and in the latter instance, treatment with the antisense PKC alpha S-oligodeoxynucleotide resulted in a doubling in median survival time ( > 80 days), with 40% long term survivors. The antisense S-oligodeoxynucleotide did not produce systemic toxicity in mice with subcutaneous or intracranial tumors after daily intraperitoneal injection for 21 or 80 days, respectively, and a scrambled S-oligodeoxynucleotide with the same nucleotide composition as the antisense S-oligodeoxynucleotide did not produce an antitumor effect. The intratumoral levels of both antisense and scrambled S-oligodeoxynucleotide in subcutaneous tumors were 2 microM after 21 daily doses of 20 mg/kg S-oligodeoxynucleotide. The antisense S-oligodeoxynucleotide selectively reduced the levels of PKC alpha in subcutaneous tumors but not those of protein kinase C epsilon or protein kinase C zeta. This is the first demonstration that the growth of glioblastoma multiforme can be suppressed by an antisense PKC alpha S-oligodeoxynucleotide and suggests that this may represent an effective therapy for this type of malignancy.

Animals↗

PubMed1996

[Emphysematous cystitis: a case report].

Emphysematous cystitis is a rare condition in which gas-forming organisms produce gas in the bladder wall and lumen. We present a case of emphysematous cystitis with neurogenic bladder. The patient was a 78-year-old man who complained of dysuria and lower abdominal soft mass. Urine culture yielded Klebsiella pneumoniae and Enterococcus faecalis. A plain X-ray film of upright position showed a large air-fluid level. The gas was demonstrated in the bladder wall and lumen on CT scan. These findings were compatible with that of emphysematous cystitis. The symptoms were improved and the intraluminal gas had disappeared on radiography after treatment with antibiotics. We reviewed 20 cases of emphysematous cystitis reported in the Japanese literature and reported clinical characteristics of 21 patients including ours here.

Aged↗

PubMed1996

[Cell adhesion proteins in the nervous system: immunoglobulin superfamily--structure, function and involvement in neurological diseases].

Cell adhesion proteins play important roles in cell-cell interactions, which regulate development and maintenance of multicellular organisms. In the nervous system, there exist unique groups of cell adhesion proteins, that are essential for elaborate neural network formation. Accumulated evidences indicate these proteins express and function at spatially and temporally defined stages of development and regeneration of the nervous system. Recent studies revealed that some mutations of cell adhesion proteins cause various neurological diseases. In this article, we review recent progress and perspectives of studies on proteins of immunoglobulin superfamily in the nervous system, focusing on their structure, physiological roles and involvement in neurological diseases.

Humans↗

PubMed1996

Cell-adhesion proteins of the immunoglobulin superfamily in the nervous system.

The unique groups of cell-adhesion proteins, such as IgSF, play essential parts in the formation and maintenance of the nervous system. Recent crystallographic studies have revealed a possible common structure of cell-adhesion proteins. The IgSF proteins are sub-grouped into simple, complex and mixed types. Accumulating evidence reveals the importance of cell-adhesion proteins in neural morphogenesis, maintenance and regeneration. They play key roles in neuronal migration, neurite outgrowth promotion, neurite fasciculation, pathfinding, target recognition, synaptogenesis and myelination. Mutations of cell-adhesion proteins result in neurological disease; for example, mutations of PO in hereditary neuropathy and mutations of L1 in hereditary hydrocephalus, MASA syndrome and spastic paraplegia type 1. Perspectives of the studies of neural cell-adhesion proteins are discussed.

Animals↗

PubMed1996

Gene therapy: targeting tumor cells for destruction.

Human gene therapy involves the transfer of genetic material into cells of a patient, either in vitro or in situ, for the therapeutic purpose of correcting or ameliorating genetic defects, alleviating disease, inhibiting infectious agents or destroying cancer cells. After identification of an appropriate disease target (inherited or acquired) for treatment, a number of basic technical issues underlie any gene therapy strategy. These include the choice of genetic material to be transferred, target cell or organ for gene modification, delivery systems and representative animal models of the targeted human disease. Tumor gene therapy represents a somewhat special category for gene therapy because its intended goal is the destruction of tissue rather than its correction or preservation. For an experimental therapeutic, cancer represents a useful target due to the paucity of effective treatments and the terminal nature of the disease. Viral vectors, currently the most widely used agents for gene delivery, generally fall into two classes; defective, which are unable to replicate; and replication-competent, which are able to replicate and spread within defined cell types. The strategies employed for cancer gene therapy range from cytotoxicity, either direct or through a 'suicide' gene-producing, to induction of a host antitumor immune response. Gene therapy is rapidly moving into the clinic, yet its efficacy remains to be demonstrated. Research into the underlying fundamentals of gene therapy discussed in this review will be critical to the ultimate success of this therapeutic modality.

Animals↗

PubMed1995

Treatment of human malignant meningiomas by G207, a replication-competent multimutated herpes simplex virus 1.

We have demonstrated that replication-competent attenuated mutants of herpes simplex virus type 1 (HSV-1) have therapeutic potential for malignant gliomas. Moreover, a recently described multiple mutant HSV (termed G207) has properties which may allow human clinical trials. G207 is able to replicate within and kill cells from three human malignant meningiomas in cell culture. In nude mice harboring s.c. human malignant meningioma (F5), G207 can inhibit growth in a dose-dependent fashion. In nude mice harboring intracranial subdural human malignant meningioma (F5), one injection of G207 caused significantly decreased tumor growth and one apparent cure with neither neurological dysfunction nor pathological changes in the surrounding brain. These results suggest that G207 should be considered for therapeutic trials in the treatment of malignant meningioma refractory to currently available therapies.

Animals↗

PubMed1995

Decrease of NCAM expression and astrocyte-neurone interaction in long-term cultured astrocytes.

In order to assess the characteristics of the older astrocyte, we obtained long-term cultured rat astrocytes (20 months) and examined the features of protein expression in relation to neuronal interaction. In short-term cultured astrocytes, NCAM expressed strongly in contrast to weak expression of laminin by both immunocytochemical and ELISA assay. On the contrary, in long-term cultured astrocytes, a marked decrease of NCAM expression was observed along with increased laminin expression compared with short-term cultured astrocytes. The long-term cultured astrocytes remained positive to anti-GFAP antibody and showed a much lower ability to interact with neurones than the short-term cultured astrocytes. NCAM may be one of the responsible molecules related to the astrocyte-neurone interaction in the developing and ageing nervous system.

Animals↗

PubMed1995

Detection of human herpesvirus 6 DNAs in samples from several body sites of patients with exanthem subitum and their mothers by polymerase chain reaction assay.

Polymerase chain reaction amplification was used to detect human herpesvirus 6 (HHV-6) DNAs in peripheral blood mononuclear cells (MNCs), plasma, saliva, stool, and urine from three patients with exanthem subitum and in peripheral blood MNCs, plasma, and saliva from their mothers. HHV-6 DNAs were detected in MNCs during and after the disease and were found in plasma only in the acute phase. The virus DNAs were also detected in saliva after recovery from the illness and were found persistently or intermittently in stool but not in urine samples after the onset of the disease. In contrast, one of the three mothers excreted HHV-6 DNAs persistently in saliva. None of the mothers had the virus DNAs in peripheral blood MNCs and plasma nor a significant increase in antibody titers to HHV-6 after possible exposure from their children. These findings suggest systemic replication of HHV-6 during the acute phase in patients with exanthem subitum and persistent infection of the virus in several organs after recovery from the disease.

Adult↗

PubMed1995

Inhibition of angiogenesis and growth of human non-malignant and malignant meningiomas by TNP-470.

Meningiomas are relatively common (22%) vascular brain tumors. 3-11% of meningiomas are malignant, and defy currently available therapy. Inhibition of neovascularization is one potential strategy for treating these hypervascular tumors. Inhibition of tumor-induced angiogenesis by TNP-470 (previously termed AGM-1470), a synthetic analogue of fumagillin, was tested on the growth of human non-malignant and malignant meningiomas in nude mice. TNP-470 significantly inhibited tumor neovascularization and tumor growth of both non-malignant and malignant meningiomas. TNP-470 is now in human trial and should be tested for efficacy in treating malignant or recurrent aggressive meningiomas.

Animals↗