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Biomedical subjects

M Shin

Publications and source records attributed to M Shin.

At least 55 records · Page 3Linked to original sources
PubMed2000

Headaches in patients with radiosurgically treated occipital arteriovenous malformations.

OBJECT: The goal of this study was to determine the prevalence, characteristics, and radiosurgical outcomes of headaches associated with occipital arteriovenous malformations (AVMs). METHODS: The authors reviewed the medical records of 37 consecutive patients with occipital AVMs who had been treated by radiosurgery to identify the radiological features of the AVMs before and after treatment and the clinical features and outcomes of headaches described in accordance with the criteria of the International Headache Society (IHS). Thirty-six patients (97.3%) were followed for a mean period of 46.6 months. The median volume of the AVMs was 1.9 cm3, to which a mean radiation dose of 21.6 Gy was delivered. In the entire study group, periodic headaches were found in 17 patients (45.9%), of whom seven (18.9%) suffered from migraines with the characteristic visual aura. Migraine was predominantly found in patients with right-sided (p = 0.038) or laterally located (p = 0.025) AVMs. Factors associated with a higher incidence of any type of headache included larger nidus volume (p = 0.02), tortuous change of feeding artery (p = 0.036), and cortical drainage with reflux in the superior sagittal sinus (p = 0.032). The actuarial rate of angiographic obliteration was 71.6% at 3 years. Headaches resolved or improved in 12 (70.6%) of 17 patients, including six (85.7%) of seven with migraine. The outcome of headache closely correlated with the obliteration results of the AVM (p = 0.002). CONCLUSIONS: A portion of occipital AVMs do cause headaches that satisfy the current IHS criteria for migraine, and the prevalence varies by the topography of the lesion. Radiosurgery can resolve headaches in the majority of treated patients.

Adolescent↗
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed1999

Frequency of sister chromatid exchange in chrysotile-exposed workers.

Chrysotile, which is an industrial carcinogen, has been shown to induce a dose-dependent increase in the frequency of sister chromatid exchange (SCE) in vitro. Authors designed this study to examine the increase of SCEs frequency in the workers occupationally exposed to chrysotile. Heparinized whole blood samples from 45 chrysotile-exposed and 45 control volunteers were cultured for 72 h. The significant difference of SCE frequency was found between chrysotile-exposed workers and control group. The highest SCEs frequency was found in chrysotile-exposed smokers, and the lowest in control non-smokers. The effect of chrysotile exposure on SCEs was marginally significant after controlling the effects of age and smoking by multiple regression analysis.

Adult↗
PubMed1999

Renal neoplasias in patients receiving dialysis and renal transplantation: clinico-pathological features and p53 gene mutations.

BACKGROUND: In Japan, the relative risk for renal cell carcinoma (RCC) in renal transplants was about 80-fold higher than that in the general population. Depressed immune surveillance due to the use of immunosuppressive agents was considered to cause cancer. Before renal transplantation, a vast majority of patients received hemodialysis, a known causative factor for acquired cystic disease of kidney (ACDK). Because ACDK is also considered to predispose to RCC, at least two risk factors for cancer accumulate in renal transplants. METHODS: In our study, clinicopathological features together with p53 gene mutations were analyzed in 218 patients with RCC: 22 received dialysis followed by renal transplantation, 39 received dialysis alone, and 157 sporadic RCC. P53 mutations were analyzed on DNA extracted from paraffin-embedded specimens with use of single strand conformation polymorphism, followed by direct sequencing. RESULTS: RCC in transplants shared several clinicopathological features with those in dialysis patients, which included small size and multiplicity of tumor, relatively high frequency of presence of ACDK, and papillary type of RCC. p53 gene mutations were infrequent in RCC of any clinical setting. CONCLUSIONS: Atrophic kidney at the end-stage of renal failure and under dialysis have lesions of ACDK that might predispose to RCC in dialysis and transplant patients.

Adult↗
PubMed1999

Peroxisome-proliferator regulates key enzymes of the tryptophan-NAD+ pathway.

Structually diverse peroxisome-proliferators (PPs) were investigated regarding their effects on NAD+ level and two key enzyme activities in the tryptophan (Trp)-NAD+ pathway in the liver of rats (Sprague-Dawley male) fed PP-containing diets freely for 2 weeks. All PPs, except for thyroxine, significantly increased hepatic NAD+ level in concert with hepatic hypertrophy. Activity of quinolinate phosphoribosyltransferase (QAPRTase), one of the key enzymes in the Trp-NAD+ pathway, was increased by the PPs which caused significant increase in the hepatic NAD+. On the other hand, alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSDase), another key enzyme in the Trp-NAD+ pathway, was drastically inhibited by all PPs except for linolenic acid, which was only slightly inhibitory. Most PPs investigated activated peroxisomal marker enzymes such as palmitoyl-CoA oxidase, catalase, and PPAR-alpha(peroxisome-proliferator activated receptor-alpha)-dependent enzymes, such as malic enzyme and l-3-glycerophosphate dehydrogenase. NAD+ was also increased in the rat hepatocytes cultured in the medium supplemented with PPs. These data suggested that regulation of the key enzymes in the Trp-NAD+ pathway was associated with PPAR-alpha directly or indirectly, and as a consequence the hepatic NAD+ was increased by PPs.

Animals↗
PubMed1999

Relief of hemiballism from a basal ganglia arteriovenous malformation after radiosurgery.

A patient with a 3-year history of progressive hemiballism presented with an unruptured arteriovenous malformation (AVM) in the contralateral caudate nucleus and putamen. PET demonstrated a matched reduction of cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in the basal ganglia and adjacent frontal lobe. The patient underwent radiosurgery for the AVM. After a period of no clinical change for 6 months, the movement disorder resolved by month 7 post-treatment. The AVM was successfully obliterated 2 years after irradiation without any significant change in the regional CBF or CMRO2.

Arteriovenous Malformations↗
PubMed1999

Effects of peroxisome-proliferators on the TRP-NAD pathway.

The mechanism of the elevation of hepatic NAD level in the rats administered clofibrate and other peroxisome-proliferators were investigated. In the hepatocytes from the clofibrate-fed rats, NAD biosynthesis from Trp, but not from nicotinic acid, was specifically stimulated. The activities of peroxisomal marker enzymes, the peroxisome-proliferator activated receptors (PPAR)-dependent enzymes and key enzymes in the Trp-NAD pathway changed in parallel with the hepatic NAD increase; the activity of quinolinate phosphori-bosyltransferase (QPRT) was increased whereas that of alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) was drastically reduced. The results strongly suggest that the hepatic NAD increase might be caused by transcription of genes coding the key enzymes of the Trp-NAD pathway via PPAR.

Animals↗
PubMed1999

Tyrosine phosphorylation and activation of Janus kinase 1 and STAT3 by sublytic C5b-9 complement complex in aortic endothelial cells.

The pathway involving Janus kinase (JAK) and signal transducers and activators of transcription (STATs) plays an important role in differentiation and proliferation of cells initiated by receptor activation. In the present study we identified the JAK and STAT proteins activated by C5b-9 in human aortic endothelial cells (AEC). JAK1 but not JAK2 was tyrosine phosphorylated in response to sublytic C5b-9. STAT3 was rapidly tyrosine phosphorylated also by C5b-9. Pertussis toxin inhibited the C5b-9 induced JAK1 activation. However, phosphorylation of STAT3 was not inhibited by Pertussis toxin, although C5b-9 induced a time-dependent nuclear translocation of STAT3. These observations indicated that JAK1 is phosphorylated by C5b-9 through activation of trimeric G proteins of the Gi/Go family. Raf-1 and ERK1 were also activated by C5b-9 in human AEC in a G protein dependent manner. Therefore, JAK1 activity may be involved in activation of Raf-1 and ERK1 via G proteins activated by C5b-9. This study demonstrates the ability of membrane-inserted C5b-9 to activate JAK1 and STAT3 proteins, thus defining new signalling pathway by which C5b-9 may regulate gene activation.

Adult↗
PubMed1999

Inhibition of topoisomerase II alpha subunit de novo synthesis by specific antisense oligonucleotides suppresses human glioma T98G cell growth.

Deoxyribonucleic acid (DNA) topoisomerases are enzymes which resolve topological problems in eukaryotic DNA, and may be involved in cell proliferation. The involvement of topoisomerase II in cell proliferation was examined in the human glioma cell line T98G. The growth rate of T98G cells was suppressed by treatment with topoisomerase II antisense oligonucleotides dose-dependently, with significant suppression at concentrations greater than of 0.1 mM. The growth rate of T98G treated with control oligonucleotide was suppressed at concentrations greater than 3.0 mM. The activity of topoisomerase II in T98G cells treated with 0.5 mM topoisomerase II antisense oligonucleotide was one fourth of that in cells treated with control oligonucleotide. When topoisomerase II translation was suppressed, the activity of topoisomerase I was increased. These results suggest that de novo synthesis of the topoisomerase II protein is required to maintain a normal growth rate in cultured T98G cells. These topoisomerases may be functionally related, and might provide compensatory mechanisms in the case of compromised function.

Antigens, Neoplasm↗
PubMed1999

[Quality of washed autologous erythrocytes from drainage-suction pumps].

High sub-pressure in high-vacuum suction bottles falls as the bottles fill up. Suction pumps with reservoir have a constant low suction level and decisive advantages. The question is: does the use of a suction pump before processing and retransfusion influence the quality of the erythrocytes? The randomized, controlled, prospective study presented here deals with drainage blood and washed autologous red blood cells (warbc) from 60 patients after hip endoprosthesis surgery. In a comparison between suction pump and redon bottle, the following parameters were studied: haematological-parameter (haemoglobin, haematocrit, erythrocyte count, leukocyte count, thrombocyte count, MCV, MCH, MCHC), vitality (osmotic fragility, 2,3-DPG) and haemolysis parameter (GOT, LDH, plasma haemoglobin, potassium). Control samples were taken immediately after operation: sample one from drainage blood before processing and sample two from warbc before retransfusion. There were no significant statistical differences between the groups. The osmotic fragility of the retransfused red blood cells was slightly above normal values, while the 2,3-DPG was normal. "Old" erythrocytes were haemolysed. The concentration of plasma haemoglobin was clearly above the normal range. In the "redon group" GOT and LDH were clearly increased. The quality of erythrocytes from suction pump reservoirs is not decisively impaired.

Blood Specimen Collection↗
PubMed1998

Complex gangliosides are essential in spermatogenesis of mice: possible roles in the transport of testosterone.

Mice, homozygous for disrupted ganglioside GM2/GD2 synthase (EC 2.4. 1.94) gene and lacking all complex gangliosides, do not display any major neurologic abnormalities. Further examination of these mutant mice, however, revealed that the males were sterile and aspermatogenic. In the seminiferous tubules of the mutant mice, a number of multinuclear giant cells and vacuolated Sertoli cells were observed. The levels of testosterone in the serum of these mice were very low, although testosterone production equaled that produced in wild-type mice. Testosterone was found to be accumulated in interstitial Leydig cells, and intratesticularly injected testosterone was poorly drained in seminiferous fluid in the mutant mice. These results suggested that complex gangliosides are essential in the transport of testosterone to the seminiferous tubules and bloodstream from Leydig cells. Our results provide insights into roles of gangliosides in vivo.

Animals↗
PubMed1998

Pyridine nucleotide levels in liver of rats fed clofibrate- or pyrazinamide-containing diets.

Hepatic NAD+, NADH, and NADPH were increased significantly 3 days after feeding rats with a 0.25% clofibrate diet, increased further after 8 days, and stayed at the same levels 14 days after feeding the diet. The NAD+/NADH ratio was decreased significantly by feeding the clofibrate diet for 8 days, while the ratio remained unchanged with a 1% pyrazinamide diet. Hepatic quinolinate phosphoribosyltransferase (QAPRTase) (EC 2.4.2.19) activity was increased to 1.8 and 1.3 times that of the control animals in the clofibrate- and the pyrazinamide-fed rats, respectively, while hepatic aminocarboxymuconate-semialdehyde decarboxylase (ACMSDase) (EC 4.1.1.45) activity was decreased to 0 and 19% of that of the control animals. The heat-treated liver homogenate from the pyrazinamide-fed rats contained inhibitory activity toward ACMSDase, while no inhibitory activity was found in the liver homogenate of the clofibrate-fed animals. We conclude that these changes of enzyme activities, which seem due to different mechanisms, may contribute to the increase of pyridine nucleotides in the liver of rats fed clofibrate or pyrazinamide.

Animals↗
PubMed1998

Prognostic factors of renal cell carcinoma: a multivariate analysis.

BACKGROUND AND OBJECTIVES: To establish appropriate therapeutic modalities for renal cell carcinoma (RCC), informations on the factors affecting prognosis of patients are essential. For this purpose, multivariate analysis including a large set of variables is necessary. METHODS: Prognostic significance of 14 clinical factors and 19 histologic factors including counting of silver-stained nucleolar organizer regions (AgNORs) were evaluated in 96 patients. Age of patients ranged from 41 to 85 (median 59) yr with a male to female ratio of 4:1. The tumors were staged based on the TNM classification as follows: 7 in stage I, 58 in stage II, 15 in stage III, and 11 in stage IV. RESULTS: The overall and metastasis-free survival rates in all patients were 80.1% and 72.7%, respectively. Multivariate analysis using Cox's proportional hazards model performed on the factors proved to be significant at the univariate analysis. Univariate analysis revealed four clinical factors including presence of macroscopic hematuria, symptoms such as pain and palpable abdominal mass, anemia, and adjuvant therapy, and nine histologic factors, including AgNOR count, to be significant for survival. Multivariate analysis showed that anemia, pathological stage, and AgNOR count were independent factors for overall survival of patients. The AgNOR count, in particular, is the only predictive factor for metastasis-free survival. CONCLUSIONS: Among various clinicopathological factors, anemia, pathological stage, and AgNOR count are significant prognosticators of RCC. The AgNOR count is also predictive factor for metastasis-free survival.

Adult↗
PubMed1998

Medical decision-making and the patient: understanding preference patterns for growth hormone therapy using conjoint analysis.

OBJECTIVES: This study examines two questions that relate to patients' role in medical decision making: (1) Do patients utilize multiple attributes in evaluating different treatment options?, and (2) Do patient treatment preferences evidence heterogeneity and disparate patterns? Although research has examined these questions by using either individual- or aggregate-level approaches, the authors demonstrate an intermediate level approach (ie, relating to patient subgroups). METHODS: The authors utilize growth augmentation therapy (GAT) as a context for analyzing these questions because GAT reflects a class of nonemergency treatments that (1) are based on genetic technology, (2) aim to improve the quality (rather than quantity) of life, and (3) offer useful insights for the patient's role in medical decision making. Using conjoint analysis, a methodology especially suited for the study of patient-consumer preferences but largely unexplored in the medical field, data were obtained from 154 parents for their decision to pursue GAT for their child. RESULTS: In all, six attributes were utilized to study GAT, including risk of long-term side effects (1:10,000 or 1:100,000), certainty of effect (50% or 100% of cases), amount of effect (1-2 inches or 4-5 inches in adult height), out-of-pocket cost ($100, $2,000, or $10,000/year) and child's attitude (likes or not likes therapy). An experimental design using conjoint analysis procedures revealed five preference patterns that reflect clear disparities in the importance that parents attach to the different attributes of growth therapy. These preference patterns are (1) child-focused (23%), (2) risk-conscious (36%), (3) balanced (23%), (4) cost-conscious (14%), and (5) ease-of-use (4%) oriented. Additional tests provided evidence for the validity of these preference patterns. Finally, this preference heterogeneity related systematically to parental characteristics (eg, demographic, psychologic). CONCLUSIONS: The study results offer additional insights into medical decision making with the consumer as the focal point and extend previous work that has tended to emphasize either an individual- or aggregate-based analysis. Implications for researchers and health care delivery in general and growth hormone management in particular are provided.

Adult↗
PubMed1998

Utility of immunohistochemical detection of high molecular weight cytokeratin for differential diagnosis of proliferative conditions of the prostate.

BACKGROUND: Differential diagnosis of adenocarcinoma from other proliferative conditions in the prostate is often problematic. Immunohistochemistry using an antibody (34 beta E12) to high molecular weight cytokeratin, specifically present in basal cells of the prostate, could clearly demonstrate the presence or absence of these cells in the proliferating glands and thus provide an important clue in cancer diagnosis. METHODS: To examine the utility of immunostaining using 34 beta E12, we examined 88 equivocal lesions. Twenty lesions with apparently benign and malignant features were added as controls. We compared the morphologic features of these lesions with their immunoreactivities toward 34 beta E12 on a personal computer display following storage on the MICROPHOT-FXA system. RESULTS: Proliferating glands in all 20 benign lesions had 34 beta E12-reactive basal cells, but none of the malignant lesions did. The equivocal lesions were categorized on morphologic grounds into 2 groups: possibly benign and possibly malignant. Forty-five (51.1%) of the 88 equivocal lesions, were positive for 34 beta E12. These included 35 of the 45 (77.8%) possibly benign lesions and 10 of the 43 (23.3%) possibly malignant lesions. Among the equivocal lesions, 10 considered possibly benign on morphologic grounds showed negative reactivities, and 10 considered possibly malignant showed positive reactivities. Even through comparison on the computer display, no difference in morphology could be discovered between the negative and positive lesions in either group. CONCLUSION: Immunohistochemical procedures using 34 beta E12 are indispensable in the diagnosis of equivocal prostate lesions.

Adenocarcinoma↗
PubMed1998

Effect of thioridazine or chlorpromazine on increased hepatic NAD+ level in rats fed clofibrate, a hypolipidaemic drug.

The effect of the phenothiazines, thioridazine and chlorpromazine, on the increased hepatic NAD+ level of rats fed clofibrate, a hypolipidaemic drug, has been investigated. Short-term (6 days) addition of phenothiazines to the diet negatively affected diet intake and body-weight gain, but increased liver weight and hepatic NAD+ levels, which was synergistic to clofibrate. The phenothiazines were shown to inhibit hepatic peroxisomal fatty acid oxidation in-vivo, as determined by the increased residual catalase activity. In hepatocytes prepared from clofibrate-fed rats, phenothiazines inhibited not only peroxisomal but also mitochondrial fatty acid oxidation to the same extent. In the hepatocytes, NAD+ was maintained at the high level until the phenothiazine concentration was increased to 0.2 mM. The result suggests that the increase of hepatic NAD+ in rats fed clofibrate is not related to peroxisomal fatty acid oxidation.

Animals↗