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Biomedical subjects

M Shin

Publications and source records attributed to M Shin.

At least 37 records · Page 2Linked to original sources
PubMed2001

Localization in situ of specific RNA by electron microscopy.

To better understand the metabolism of RNA in nuclei, the analysis of precise nuclear distribution of specific RNA would be essential. For this purpose, nonradioactive electron microscopic (EM) in situ hybridization may be the most appropriate technique while the details required for the technique have not been fully established. In the present study, we attempted to localize 28S and 18S rRNAs in the nuclei of mouse Sertoli cells by EM in situ hybridization as a model system. After various preliminary experiments we chose the pre-embedding method; fresh-frozen sections of mouse testis were fixed with a mixture of 4% paraformaldehyde and 0.1% glutaraldehyde, digested with 10 microg/ml of proteinase K and hybridized with thymine-thymine (T-T) dimerized oligodeoxynucleotides (oligo-DNA) complementary to a part of 28S and 18S rRNAs. Then, the T-T dimers were detected enzyme-immunohistochemically with horseradish peroxidase (HRP) labeled anti-T-T dimer. After osmification of HRP products, the sections were embedded in Epon resin, cut into 100 nm ultra-thin sections and observed under a transmission electron microscope. As a result, we successfully localized both 28S and 18S rRNAs in the dense fibrillar and granular components of the nucleolus, showing the usefulness of nonradioactive EM in situ hybridization in the nuclear localization of specific RNA.

Animals↗
PubMed2000

Risk factors for neurological complications after acoustic neurinoma radiosurgery: refinement from further experiences.

PURPOSE: Further actuarial analyses of neurological complications were performed on a larger population treated by stereotactic radiosurgery at our institution, to establish the optimal treatment parameters. METHODS AND MATERIALS: Between June 1990 and September 1998, 138 patients with acoustic neurinomas underwent stereotactic radiosurgery at Tokyo University Hospital. Of these, 125 patients who received medical follow-up for 6 months or more entered the present study. Patient ages ranged from 13 to 77 years (median, 53 years). Average tumor diameter ranged from 6.7 to 25.4 mm (mean, 13. 9 mm). Maximum tumor doses ranged from 20 to 40 Gy (mean, 29.8 Gy) and peripheral doses from 12 to 25 Gy (mean, 15.4 Gy). One to 12 isocenters were used (median, 4). Follow-up period ranged from 6 to 104 months (median, 37 months). The potential risk factors for neurological complications were analyzed by two univariate and one multivariate actuarial analyses. Neurological complications examined include hearing loss, facial palsy, and trigeminal nerve dysfunction. Variables included in the analyses were four demographic variables, two variables concerning tumor dimensions, and four variables concerning treatment parameters. A variable with significant p values (p < 0.05) on all three actuarial analyses was considered a risk factor. RESULTS: The variables that had significant correlation to increasing the risk for each neurological complication were: Neurofibromatosis Type 2 (NF2) for both total hearing loss and pure tone threshold (PTA) elevation; history of prior surgical resection, tumor size, and the peripheral tumor dose for facial palsy; and the peripheral tumor dose and gender (being female) for trigeminal neuropathy. In facial palsies caused by radiosurgery, discrepancy between the course of palsy and electrophysiological responses was noted. CONCLUSION: Risk factors for neurological complications seem to have been almost established, without large differences between institutions treating a large number of patients by radiosurgery. Radiosurgical doses and tumor dimensions were considered the two important risk factors for the 7th and 5th nerve injuries. Neurofibromatosis Type 2 was an important factor for hearing loss.

Adolescent↗
PubMed2000

Formation of Copper(II) Thiocyanato and Cadmium(II) Iodo Complexes in Micelles of Nonionic Surfactants with Varying Poly(ethylene oxide) Chain Lengths.

Formation of copper(II) thiocyanato and cadminum(II) iodo complexes in micelles of poly(ethylene oxide) (PEO)-type nonionic surfactants with varying PEO chain lengths of 9.5 (Triton X-100), 30 (Triton X-305), and 40 (Triton X-405) has been studied by titration spectrophotometry and calorimetry at 298 K. In a given surfactant solution, all data obtained were analyzed by assuming formation of ternary complexes MX(n)Y(m)((2-n)+) (M = Cu(II),Cd(II); X = SCN(-), I(-); Y = surfactant), and the complexes thus form in aqueous phase (m = 0) or in micelles (m = 1). In the Cu(II)-SCN(-) system, spectrophotometric data obtained by varying concentrations of the surfactant can be explained well in terms of formation of Cu(NCS)(2)Y in micelles and Cu(NCS)(+) and Cu(NCS)(2) in an aqueous phase, and it turned out that formation constant of Cu(NCS)(2)Y increases with increasing PEO chain length. In the Cd(II)-I(-) system, the formation of CdI(3)Y(-) and CdI(4)Y(2-) is concluded in micelles, and that of CdI(+), CdI(3)(-), and CdI(4)(2-) in an aqueous phase. Interestingly, formation enthalpies of CdI(3)Y(-) and CdI(4)Y(2-) become significantly less negative with increasing PEO chain length. This suggests that transfer of the complexes from aqueous solution to a hydrophobic octylphenyl (OP) moiety in micelles is significantly more exothermic than that to a hydrophilic PEO one. Thermodynamic parameters of transfer of CdI(3)(-) and CdI(4)(2-) from aqueous solution to the OP and PEO moieties of micelles have been evaluated. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Extent and zonal distribution of prostatic intraepithelial neoplasia in patients with prostatic carcinoma in Japan: analysis of whole-mounted prostatectomy specimens.

BACKGROUND: Prostatic intraepithelial neoplasia (PIN), an intraluminar proliferation of epithelial cells in ducts and acini, is divided into high-grade (HGPIN) and low-grade (LGPIN), based on morphologies. HGPIN is considered to be a putative precursor of prostatic adenocarcinoma (PCA). Information on PIN has been limited in Japan, because PIN had not been regarded as a precursor lesion for PCA. METHODS: In this study, extent and zonal distribution of PIN together with its relationship with PCA were examined in totally embedded radical prostatectomy specimens obtained from 70 patients with PCA. Fifty-three patients received androgen deprivation therapy (castrated) and remaining 17 did not (noncastrated). RESULTS: Frequency of HGPIN in noncastrated cases (76%) was much higher than that in castrated cases (26%) (P < 0.001). LGPIN showed the same tendency, but the difference was smaller. Difference in mean number of HGPIN in noncastrated and castrated cases (12.0 and 6.4, respectively) was more marked than in LGPIN (6.4 and 5.1, respectively). Reduction rate of mean size in HGPIN (26%) by the androgen deprivation therapy was larger than in LGPIN. When evaluated in noncastrated cases, the coexistence of PCA and HGPIN was found in 76% of cases in the nontransition and 53% in the transition zone. Close association of PCA and PIN (</=2 mm distance between lesions) was more frequently found in HGPIN (55% of lesions) than in LGPIN (37%) (P < 0.05). Frequency of close association of HGPIN with PCA was 65% in the nontransition and 35% in transition zone. CONCLUSIONS: The present study from Japan supports the etiological importance of HGPIN in the development of PCA. The effect of androgen deprivation therapy is much more marked in HGPIN than in LGPIN.

Adenocarcinoma↗
PubMed2000

A single institutional outcome analysis of Gamma Knife radiosurgery for single or multiple brain metastases.

Although Gamma Knife stereotactic radiosurgery (SRS) is widely used for metastatic brain tumors, optimal patient selection and treatment strategy continue to be investigated. The aim of this study was to provide treatment results with Gamma Knife SRS and to establish prognostic factors. Of the 54 patients treated from 1990 to 1997, 51 patients were evaluable. There were 28 males and 23 females, with a median age of 60 years. Median Karnofsky Index was 80. There were 19 non-small cell lung cancers, eight colon cancers, six renal cell cancers, five ovarian cancers, four gastric cancers, three breast cancers, and six others. Primary tumors were controlled in 33 patients, and extracranial tumors were absent in 25 patients. Sixty-eight metastatic brain tumors in 37 patients underwent SRS as an initial treatment for the brain metastasis. Brain metastasis was solitary in 32 patients. Conventional radiation was combined with SRS in 29 patients, 24 of whom received whole brain radiotherapy. Eight patients had some form of surgical resection. Median survival time was 7.4 months. Five-year actuarial survival and local control rates were 16 and 52%, respectively. Median duration time of keeping pretreatment quality of life was 6.9 months. On a multivariate analysis, uncontrolled primary tumor, combined conventional radiotherapy, and performance status were statistically significant prognostic factors. Four patients who underwent whole brain radiation developed low grade dementia.

Adult↗
PubMed2000

Effects of various decalcification protocols on detection of DNA strand breaks by terminal dUTP nick end labelling.

To analyse DNA strand breaks by terminal deoxy(d)-UTP nick-end labelling (TUNEL) in calcified tissues including bones and teeth, it is important to decalcify the tissues first. However, the effects of decalcifying reagents on the integrity of DNA are largely unknown. In the present study, we evaluated the usefulness of various decalcifying reagents including 10% EDTA (pH 7.4), 5% trichloroacetic acid (TCA), 5% formic acid, 5% HCl, 10% nitric acid, Plank-Rychlo's solution, Morse's solution and K-CX solution in TUNEL staining. Mouse maxilla was selected as the experimental system. Apoptotic cells naturally occurring in the epithelium were analysed. Tissues were assessed by soft X-ray imaging to confirm complete decalcification. The time required for decalcification of the tissue was 7 days with 10% EDTA and 2 days with other decalcifiers. Decalcified tissues were stained with Methyl/Green-Pyronine Y or 4',6-diamidino-2-phenylindole for assessment of DNA integrity. Nuclei of epithelial cells were strongly positive for both dyes after decalcification with 10% EDTA, 5% TCA, Morse's solution and 5% formic acid. The other reagents failed to retain DNA. Our results demonstrated good TUNEL staining of the maxilla treated with 10% EDTA or 5% TCA. Based on the required time for processing and the signal-noise ratio, we recommend 5% TCA as the decalcifying reagent to analyse for DNA strand breaks.

Animals↗
PubMed2000

Radiosurgery of meningeal melanocytoma.

The authors present a case of meningeal melanocytoma arising from Meckel's cave. A coal-black, vascular tumor was partially removed by surgery. Histopathologically, the tumor lacked anaplastic features. Immunohistochemical studies confirmed that the tumor was of neuroectodermal origin and had low proliferating activity. The patient underwent gamma knife radiosurgery for the residual tumor, in which 25 Gy of radiation was delivered to the tumor margin. Three years after irradiation, the tumor showed marked shrinkage without complication.

Adult↗
PubMed2000

Mutagenicity of recombinant antihemophilic factor (GC-gamma AHF).

This study was carried out to evaluate the mutagenic potential of recombinant antihemophilic factor VIII (GC-gamma AHF). Salmonella typhimurium (S. typhimurium) reversion assay with/without histidine moiety, chromosomal aberration assay on Chinese hamster lung (CHL) fibroblast cells and in vivo micronucleus assay using mouse bone marrow cells and supravital micronucleus assay using peripheral blood were performed. GC-gamma AHF containing histidine did show inconsistent and irregular mutagenic effects on S. typhimurium TA98, TA100, TA1535 and TA1537 both in the absence and presence of the metabolic activation system, however, GC-gamma AHF without histidine showed no mutagenic effects regardless of the metabolic activation system, thus suggesting that the histidine moiety in GC-gamma AHF might cause inconsistent mutagenic effect. Also GC-gamma AHF did not increase the number of cells having structural or numerical chromosome aberration in the cytogenetic test. In classical and supravital micronucleus assay, no significant increases were observed in the occurrence of micronucleated polychromatic erythrocytes and micronucleated peripheral lymphocytes in male ICR mice. These results strongly indicate that GC-gamma AHF has no genetic toxicity under these experimental conditions.

Animals↗
PubMed2000

Stereotactic radiosurgery for tentorial dural arteriovenous fistulae draining into the vein of Galen: report of two cases.

OBJECTIVE AND IMPORTANCE: Treatment of tentorial dural arteriovenous fistulae (DAVFs) primarily draining into the vein of Galen remains a therapeutic challenge. We present two cases of ruptured galenic DAVFs that were successfully treated with gamma knife radiosurgery. CLINICAL PRESENTATION: Patient 1, a 66-year-old woman, experienced a sudden onset of headache and loss of consciousness. Neuroimaging studies revealed intraventricular hemorrhage and a DAVF with aneurysmal dilation of the vein of Galen. The DAVF was supplied by tentorial branches of the right meningohypophyseal artery and bilateral supracerebellar arteries, which drained directly into the vein of Galen. Patient 2, a 64-year-old woman, experienced subarachnoid hemorrhage. Cerebral angiography revealed a galenic DAVF at the falcotentorial junction, which was supplied by bilateral supracerebellar arteries. This patient had an aneurysm at the origin of the left supracerebellar artery. INTERVENTION: Both patients were treated with gamma knife radiosurgery. In each case, the fistula was exclusively targeted and a dose of more than 20 Gy was delivered. Complete obliteration of the fistula was confirmed 27 and 29 months after radiosurgery for Patients 1 and 2, respectively, whereas the normal venous structures of the galenic system were preserved. CONCLUSION: Gamma knife radiosurgery is an effective treatment modality for DAVFs primarily draining into the vein of Galen. Irradiation doses of more than 20 Gy, strictly limited to the fistulae, seem to be sufficient for successful obliteration of these high-risk vascular lesions, with minimal invasiveness.

Aged↗
PubMed2000

p53 mutations in prostatic intraepithelial neoplasia and concurrent carcinoma: analysis of laser capture microdissected specimens from non-transition and transition zones.

Prostatic intraepithelial neoplasia (PIN) is characterized by intraluminal proliferation of epithelial cells and is divided into high-grade (HGPIN) and low-grade (LGPIN) lesions. HGPIN is regarded as the most likely precursor of prostatic cancer (PCA). Microdissected DNA selectively extracted from paraffin-embedded sections of 27 cases with PCA were analyzed for p53 mutation in exons 5 - 8 by single-strand conformation polymorphism of polymerase chain reaction-amplified DNA fragments (PCR-SSCP) followed by direct sequencing. These patients received total prostatectomy (27 cases). After a review of histologic sections, DNA was extracted from 193 locations; 111 lesions from 27 cases with HGPIN (75 lesions from non-transition zone and 36 from transition zone), 55 lesions from 27 cases with PCA (30 lesions from non-transition zone and 25 from transition zone), and 27 from 27 benign glands. Analysis revealed 27 mutations of the p53 gene in 24 lesions from 12 cases. Benign glands adjoining PIN and / or PCA had no mutations. All mutations were point mutations: 17 missense, 7 silent, and 2 nonsense. Mutations were detected in 6 cases (22.2%) or 13 of 111 lesions (11.7%) with HGPIN and 8 cases (29.6%) or 11 of 55 lesions (20.0%) with PCA. In a given case, HGPIN and PCA lesions had different p53 mutations from each other, suggesting multiclonal development of prostatic precancerous lesions. The frequency of p53 mutation of PCA was significantly higher in the non-transition zone (33.3%) than in the transition zone (4%), and higher in the stage T3 cases (30.3%) than in the stage T2 cases (4.5%, 1 of 22 lesions) (both P < 0.05). Frequency of p53 mutation of PIN in the non-transition zone (14.7%) was higher than that in the transition zone (5.6%), although the difference was not significant. The frequency rate of p53 mutation in HGPIN close to PCA ( </= 2 mm) was significantly higher (24%) than that in HGPIN lesions > 2 mm from PCA (3%). All these findings indicate that the p53 gene mutations are involved in prostatic carcinogenesis and explain why the non-transition zone is the predominant site of PCA.

Genes, p53↗
PubMed2000

Results of radiosurgery for brain stem arteriovenous malformations.

OBJECTIVE: To assess the treatment results of radiosurgery for brain stem arteriovenous malformations (AVMs) and to seek optimal dose and treatment volume prescription for these lesions. METHODS: The clinical and radiological data of 30 consecutive patients with brain stem AVM treated with gamma knife radiosurgery were retrospectively reviewed with a mean follow up period of 52.2 months. There were 26 patients with previous haemorrhages and 21 with neurological deficit. Seventeen AVMs were located in the midbrain, 11 in the pons, and two in the medulla oblongata. All of the lesions were small with the intra-axial component occupying less than one third of the area of brain stem parenchyma on axial section of multiplanar MRI or CT. The mean diameter of the nidus was 1.26 cm, and the nidus volume within the brain stem parenchyma ranged from 0.1 to 2.0 cm(3). The mean radiation dose to the AVM margin was 18.4 Gy. RESULTS: The actuarial 3 year obliteration rate was 52.2%; 69.4% in cases treated with standard doses (minimum target dose, 18-20Gy), and 14.3% in cases treated with low doses (<18 Gy) (p<0.05). Two patients sustained symptomatic radiation injury, but there was no permanent neurological deficit caused by radiosurgery. Five patients had haemorrhage from the AVM after irradiation, including four fatal cases, resulting in a 4.0% annual rate of post-treatment bleeding. CONCLUSIONS: Radiosurgery is a viable treatment modality for patients with small deep parenchymal brain stem AVMs. A standard radiosurgical dose is safe and effective when directed to a small treatment volume. However, latent interval haemorrhage remains a significant problem until the nidus is obliterated completely.

Adolescent↗
PubMed2000

Transition zone biopsy in the detection of prostate cancer.

OBJECTIVE: About 25% of all prostate cancers occur in the transition zone (TZ). We analyzed the impact of 4 systematic TZ and 2 systematic apex (AP) biopsies in addition to systematic sextant biopsies in an effort to establish the diagnostic importance of early prostate cancer. METHODS: One hundred and thirty patients underwent systematic transperineal multipoint prostate biopsy (biopsy of 12 sites, including 4 TZ and 2 AP biopsies). RESULTS: Forty-one of 130 men (31.5%) had biopsy specimens positive for cancer, and cancer originated in the TZ alone in 4 of these 41 patients (9.8%). Fourteen patients underwent radical retropubic prostatectomy. We compare the pathological findings of radical prostatectomy specimens and biopsy results. Prostate cancers predicted to be stage T(2c) by TZ biopsy were all classified as pT(2c) or greater. CONCLUSIONS: Routine TZ biopsy does not substantially increase the prostate cancer detection rate; however, it can be useful in patients who require repeat biopsy.

Aged↗
PubMed2000

Assay of DNA photolyase activity in spinach leaves in relation to cell compartmentation-evidence for lack of DNA photolyase in chloroplasts.

Spinach cyclobutane pyrimidine dimer (CPD)-specific DNA photolyase was successfully detected in leaf extracts by an assay system for plant photolyase using an improved enzyme-linked immunosorbent assay (ELISA) which was newly introduced by novel horseradish peroxidase (HRP)-linked CPD specific monoclonal antibodies. The assay system includes two main steps: a photorepair reaction of CPD introduced in substrate DNA and measurement of CPD remained after the photorepair by the improved ELISA. When CPD- induced salmon sperm DNA was used as a substrate, high CPD-photolyase activities were observed in the enzyme fraction prepared from whole spinach leaf extracts, but not from chloroplast extracts. This strongly suggests that spinach CPD-specific photolyases are localized in cell compartments other than chloroplasts.

Animals↗
PubMed2000

Heat shock treatment protects human HL-60 cells from apoptosis induced by lectin II isolated from Korean mistletoe, Visum album var. Coloratum.

Mistletoe lectin II (ML II) isolated from Korean mistletoe (Viscum album var. Coloratum), an effective therapeutic agent for cancers, is known to induce cell death via apoptosis. In the present study, we found the protective effect of heat shock treatment of human leukemia HL-60 cells against ML II-induced apoptosis. Exposure of HL-60 cells to ML II for 4 h resulted in apoptosis of the cells, which was evaluated by examining "DNA ladder" formation and DNA fragmentation assay. The DNA fragmentation was significantly reduced in the cells subjected to heat shock treatment by incubation at 42 degrees C for 1 h and subsequently allowed to recover for 2-16 h at 37 degrees C, prior to exposure to ML II. HL-60 cells transfected with heat shock protein (hsp) 70 gene exhibited resistance to ML II-induced apoptosis very similar to that seen when untransfected cells were heat-shocked. These results indicate that ML II-induced apoptosis in HL-60 cells is inhibited by heat shock treatment, at least in part, via a hsp 70-mediated mechanism.

Apoptosis↗
PubMed2000

Protein kinase A or C modulates the apoptosis induced by lectin II isolated from Korean mistletoe, Viscum album var. Coloratum, in the human leukemic HL-60 cells.

Mistletoe lectins (MLs) are increasingly used as an anticancer drug in the treatment of human tumors. The cytotoxic activity of MLs against tumor cells is due to programmed cell death (apoptosis). The up- or down-regulation of protein kinase A (PKA) or C (PKC) is known to be associated with the regulation of drug-induced apoptosis. Previously, we isolated cytotoxic MLII from the extract of Korean mistletoe (Viscum album var. Coloratum) and characterized its biochemical properties. The present study was designed to investigate the role of PKA and PKC in MLII-induced apoptosis. Exposure of human leukemia HL-60 cells to various doses of MLII resulted in apoptosis. However, the treatment of these cells with dibutyl-cyclic AMP (DB-cAMP), PKA activator, or 12-O-tertadecanoyl phorbol 13-acetate (TPA), PKC activator, suppressed MLII-induced apoptosis. Furthermore, KT5720 and staurospoline, PKA and PKC inhibitors, respectively, reversed the suppression by DB-cAMP and TPA in the MLII-induced apoptosis of HL-60 cells. These results suggest that the activation of PKA or PKC was involved in the suppression of MLII-induced apoptosis in HL-60 cells. Collectively, these results indicate that activation of PKA or PKC in HL-60 cells may confer protection against MLII-induced apoptosis.

Apoptosis↗
PubMed2000

Benign aqueductal cyst causing bilateral internuclear ophthalmoplegia after external ventricular drainage. Case report.

The introduction of magnetic resonance (MR) imaging to the field of neuroimaging has allowed detection of various lesions that cause aqueductal stenosis. The authors report the case of a 3-year-old boy in whom a benign ventricular cyst developed in the aqueduct. The patient became drowsy after having complained of headache and vomiting; MR imaging revealed mild triventricular dilation and a normal-sized fourth ventricle. Repeated MR imaging performed 1 week later revealed an aqueductal cyst that had markedly enlarged during the intervening period. An external ventricular drainage system was installed, but recovery of consciousness in the child was unsatisfactory and a new bilateral internuclear ophthalmoplegia developed. Fenestration of the cyst wall and placement of a ventriculocisternostomy in the third ventricle were performed simultaneously by using a flexible neuroendoscope. By 2 weeks postsurgery, the patient's neurological symptoms had completely resolved. This case illustrates that simple rerouting of ventricular cerebrospinal fluid (CSF) can aggravate the symptoms of this rare lesion by causing severe compression of periaqueductal structures by a cyst that maintains a high intracystic pressure. Endoscopic surgery was an excellent choice of treatment to achieve both cyst fenestration and normalization of intracranial CSF pressure by creating a ventriculocisternostomy.

Cerebral Aqueduct↗
PubMed2000

Neuroendoscopic aqueductal stent placement procedure for isolated fourth ventricle after ventricular shunt placement. Case report.

Isolated fourth ventricle (IFV) is a rare complication in patients who undergo shunt placement, and it is not easily corrected by surgical procedures. The authors report a case of IFV that was successfully treated with an aqueductal stent placed under direct visualization by using a neuroendoscope. This 36-year-old suffered meningitis after partial resection of a brainstem pilocytic astrocytoma, and subsequently developed hydrocephalus for which a ventriculoperitoneal shunt was placed. Nine months later, the patient presented with progressive cerebellar ataxia, and magnetic resonance imaging revealed slitlike supratentorial ventricles and a markedly enlarged fourth ventricle, which were compatible with the diagnosis of IFV. The surgical procedure described was performed under visualization through a styletlike slim optic fiberscope inserted into a ventricular catheter. The catheter, with the endoscope inside it, was passed through the foramen of Monro and then through the aqueduct to reach the enlarged fourth ventricle, where membranous occlusion of the foramen of Magendie was clearly visualized. The tip of the catheter was placed in the fastigium of the fourth ventricle. After the procedure, the size of the fourth ventricle was reduced and the patient's symptoms improved. Thus, it is concluded that endoscopic aqueductal stent placement is a simple and safe surgical procedure for treatment of IFV.

Adult↗