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Biomedical subjects

N Sato

Publications and source records attributed to N Sato.

At least 343 records · Page 19Linked to original sources
PubMed2000

Choroid plexus changes after temporal lobectomy.

BACKGROUND AND PURPOSE: Postoperative contrast-enhanced MR imaging of the brain is routinely used when evaluating for residual or recurrent brain tumor. It is imperative to be aware of morphologic changes and imaging features that typically occur in response to surgical manipulation at the postoperative site to avoid misinterpretation of imaging findings. Our purpose was to determine normal postoperative changes and alterations in the choroid plexus among patients who had undergone temporal lobectomy in order to distinguish this appearance from pathologic changes that may be seen in the presence of infection or recurrent tumors. METHODS: We reviewed 159 MR scans from 95 patients with hippocampal sclerosis or gliosis who underwent temporal lobectomy for treatment of intractable epilepsy. Choroid plexus location and size were assessed on contrast-enhanced T1-weighted images. RESULTS: After temporal lobectomy, the choroid plexus enlarged and sagged into the resection site. Increase in the size of the choroid plexus occurred in 58% of cases overall. The degree of enhancement also increased after surgery, sometimes resulting in a nodular pattern of enhancement. The changes were most marked during the 1st week after temporal lobectomy, and showed an enlarged, markedly enhancing choroid plexus on 86% of the scans. CONCLUSION: Postoperative changes of the choroid plexus after temporal lobectomy include sagging into the resection site, an increased size, and an increased degree of enhancement. Normal postoperative morphologic characteristics may mimic neoplastic enhancement pattern. Familiarity with this appearance is important to avoid a pitfall in diagnosis of recurrent postoperative temporal lobe neoplasms.

Adolescent↗
PubMed2000

[Medulloblastoma].

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Brain Neoplasms↗
PubMed2000

[Myeloschisis].

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Humans↗
PubMed2000

Transcription factor Sp3 activates the liver/bone/kidney-type alkaline phosphatase promoter in hematopoietic cells.

The promoter region of the liver/bone/ kidney-type alkaline phosphatase gene was examined to define the cis-acting regulatory sequences and transcription factors responsible for its expression in hematopoietic cells. Transient transfection experiments revealed that regions deleted up to -154 base pairs upstream from the transcription initiation site had significant activities to induce bacterial chloramphenicol acetyltransferase gene. The shortest DNA fragment was found to contain three GC boxes in addition to a TATA box. Electrophoretic mobility shift assay and Southwestern analysis showed that Sp3 could bind to the fragment. Western blot analysis also detected Sp3 protein in eluate from the DNA probe mixed with the nuclear extracts. Through the use of Drosophila Schneider cells that lack the Sp1 family of transcription factors, Sp3 was shown to activate the basal promoter in a dose-dependent manner. When the amount of Sp3 was limited, the most proximal GC box was found to be critical for the basal promoter activity.

Alkaline Phosphatase↗
PubMed2000

Establishment and characterization of a breast cancer cell line expressing Na+/I- symporters for radioiodide concentrator gene therapy.

UNLABELLED: 131I therapy is a widely accepted treatment for metastatic differentiated thyroid cancer. To investigate the feasibility of 131I therapy for breast cancer, we established breast cancer cells stably expressing Na-/I- symporter (NIS) gene that can be modulated and studied in vitro and in vivo. METHODS: We transfected rat NIS genes into a human breast cancer cell line (MCF7) by electroporation. Iodide accumulation was evaluated under various extracellular concentrations of sodium and iodide, and iodide efflux was also assessed. Biodistribution and tumor imaging were studied using tumor-bearing mice. RESULTS: A novel cell line (MCF3B), stably expressing the NIS gene, was established from MCF7. MCF3B took up 44 times more radioiodide in vitro than MCF7 did. Iodide uptake was completely inhibited by 1 mmol/L perchlorate and was dependent on external sodium and iodide concentrations. Iodide efflux from MCF3B cells was slower (half-life [T 1/2] > 27 min) than from FRTL5 thyroid cells (T 1/2 = 4 min). In the biodistribution study using MCF3B-xenografted mice, high tumor uptake of 125I was shown (16.73%) at 1 h after injection, and tumor-to-normal tissue ratios were also high (4.84-21.28), except in the stomach (0.47). However, the iodide accumulation in the tumor lessened with time, reaching less than 1% at 24 h after injection. CONCLUSION: Our preliminary data indicate that NIS-based gene therapy may be applied by concentrating a lethal dose of radiation in tumor cells in vivo, but further investigation is necessary to determine a method of maintaining radioiodine in the cells to allow greater therapeutic effects.

Animals↗
PubMed2000

Environmental effects on acidic lipids of thylakoid membranes.

The contents of the chloroplast acidic lipids, SQDG (sulphoquinovosyldiacylglycerol) and PG (phosphatidylglycerol), were reduced in the cells of Chlamydomonas reinhartdtii with exposure to sulphur- or phosphorus-source limitation, respectively. The decrease in the content of one acidic lipid was accompanied by an increase in the content of the other acidic lipid, which resulted in the maintenance of a certain level of total acidic lipids of chloroplast membranes. On the other hand, the content of each acidic lipid was little affected by temperature stresses during cell growth.

Animals↗
PubMed2000

[An approach to early genetic alterations in precancerous cells].

To investigate the potential role of the PTEN tumor-suppressor gene in the carcinogenesis of ovarian endometrioid carcinoma and its related subtype, clear cell carcinoma, we examined 20 ovarian endometrioid carcinomas, 24 clear cell carcinomas and 34 solitary endometrial cysts of the ovary for LOH at 10q23.3 and point mutations of the PTEN gene, using a laser-assisted microdissection method. LOH was found in 8 of 19 ovarian endometrioid carcinomas (42.1%), 6 of 22 clear cell carcinomas (27.3%) and 13 of 23 solitary endometrial cysts (56.5%). Somatic mutations in the PTEN gene were identified in 4 of 20 ovarian endometrioid carcinomas (20.0%), 2 of 24 clear cell carcinomas (8.3%) and 7 of 34 solitary endometrial cysts (20.6%). In 5 endometrioid carcinomas with endometriosis, 3 displayed LOH events common to both the carcinoma and the endometriosis. In 7 clear cell carcinomas with endometriosis, 3 displayed LOH events common to both the carcinoma and the endometriosis. In no cases there were LOH events in the endometriosis only. These results indicate that inactivation of the PTEN gene is an early event in the development of both endometrioid and clear cell carcinoma of the ovary. A laser-assisted microdissection method enables us to collect target cells without contamination by non-tumor cells. We expect that this technique will be very useful for investigating genetic alterations in cancerous or precancerous lesions. Early genetic alterations in various precancerous cells detected by light microscopy can be readily identified by the tissue-microdissection method.

Adenocarcinoma, Clear Cell↗
PubMed2000

[Pulmonary thromboendarterectomy for chronic pulmonary thromboembolism in three patients with systemic lupus erythematosus and antiphospholipid syndrome].

Pulmonary hypertension (PH) is a serious and often fatal complication of systemic lupus erythematosus (SLE). Several potential mechanisms have been postulated for narrowing of vessels as a result of pulmonary vasculitis and pulmonary thromboembolism caused by antiphospholipid antibodies. Pulmonary thromboendarterectomy for chronic pulmonary thromboembolism is performed to alleviate pulmonary hypertension. We report three rare cases of SLE with antiphospholipid syndrome in patients who presented with PH secondary to chronic pulmonary thromboembolism. Pulmonary thromboendarterectomy was performed, and all patients remained well without deterioration of PH after surgery. Pulmonary thromboendarterectomy should be considered as an effective method of treatment for this disease.

Adult↗
PubMed2000

Nuclear matrix protein (NMP) levels in patients with acute pancreatitis.

Nuclear matrix protein (NMP) is an index of apoptosis. We measured NMP in 22 patients with acute pancreatitis and investigated the relationship between severity and NMP. We also measured tumor necrosis factor-alpha (TNF-alpha) and investigated the relationship between NMP and TNF-alpha. The NMP value increased significantly as the pancreatitis became more increasingly severe, and the NMP values were significantly higher in the group with multiple organ dysfunction syndrome (MODS) than in the group without MODS. A comparison of the NMP values in the group that survived and the group that died revealed higher NMP values in the former. A significant correlation was found between the NMP values and the TNF-alpha values, suggesting that apoptosis may contribute to the pathophysiology of acute pancreatitis.

Acute Disease↗
PubMed2000

Soluble Fas and soluble Fas L levels in patients with acute pancreatitis.

The FasL-Fas system is an apoptosis induction system and plays an important role in homeostasis and biophylaxis. The present study was conducted to investigate soluble Fas (sFas), soluble Fas ligand (sFasL), and tumor necrosis factor alpha (TNF-alpha) in patients with acute pancreatitis. As acute pancreatitis became severe, the levels of sFas in the serum increased significantly, while those of sFasL decreased significantly. A significant inverse correlation was observed between the serum levels of sFas and those of sFasL. Also, a significant positive correlation was observed between the levels of TNF-alpha and sFas. A greater increase in serum sFas and decrease in serum sFasL levels was observed in patients with complicating multiple organ dysfunction syndrome (MODS) than in those without it. The results of the study suggest that the pathological aggravation of acute pancreatitis could be related to changes in the Fas-FasL system.

Acute Disease↗
PubMed2000

Immobilization on the day 14th does not disrupts the basic diurnal rhythm of bone resorption.

Weight bearing and physical activity are important mechanical stimuli to bone growth and metabolism, and microgravity, such a space flight and/or bed rest, induces bone resorption and bone loss. An increased excretion of urinary Ca, an increased bone resorption and a decreased bone mineral density (BMD) have been observed in bed rest experiment of healthy subjects. Bone resorption markers show the specific circadian rhythms in human. Cross-linked carboxyl-terminal telopeptide of type I collagen (ICTP) and the urinary excretion of deoxypyridinoline (Dpy) are the highest in the early morning and the lowest late at night. Bed rest immobilization might influence these rhythms, due to no mechanical loading with loss of daily life activity. Bone resorption markers in healthy subjects had been compared between before and during bed rest to determine disruption of diurnal rhythms of bone resorption.

Acid Phosphatase↗
PubMed1999

Interleukin-10 reduces natural killer (NK) sensitivity of tumor cells by downregulating NK target structure expression.

We examined the effect of exogenous IL-10 on the sensitivity of rat W14 and W31 tumor cells to natural killer (NK) cell-mediated cytotoxicity in relation to previously identified NK target structure (NKTS) expressed on these cells. We also examined the effect of endogenous interleukin-10 (IL-10) on rat IL-10 cDNA-introduced W31 cells (W31T-H, a high-IL-10-producer clone; W31T-L, a low-IL-10-producer clone). Both exogenous and endogenous IL-10 had no effect on the proliferative activity of these cells, but incubation of cells with recombinant human (rh) IL-10 resulted in a dose-dependent decrease in the expression of NKTS recognized by mAb 109. The expression level of NKTS on W31T-H cells was dramatically decreased compared with that on W31T-L cells and parental W31 cells. In addition, treatment of W31 cells with the culture supernatants of W31T-H cells could downregulate the expression of the NKTS. Moreover, NK sensitivity of W31T-H was suppressed down to a level equivalent to that of W31 cells pretreated with exogenous rhIL-10, and cytolysis could no longer be inhibited by mAb 109. We previously demonstrated that IL-10 downregulated MHC class I expression in this model. Nevertheless, NK susceptibility was also decreased. Taken together, these results suggest that the IL-10-mediated decrease in NKTS expression has a larger effect than decreased MHC class I expression on NK sensitivity. Thus, our data reveal a novel mechanism for an IL-10-mediated escape of tumor cells from host immune surveillance by downregulation of NKTS expression.

Animals↗
PubMed1999

On-line microextraction of metal traces for subsequent determination by plasma atomic emission spectrometry using pH peak focusing countercurrent chromatography.

Metal ions were highly efficiently enriched by pH peak focusing high-speed countercurrent chromatography. The peak intensity for a 10-mL standard sample in the effluent stream was increased over 100-fold compared to conventional plasma atomic emission spectrometry. Ca, Cd, Cu, Mg, Mn, Ni, and Zn are chromatographically extracted in a basic organic stationary phase containing a complex-forming reagent such as bis(2-ethylhexyl) phosphoric acid. After the sample solution is introduced into the column, metal ions remain around the sharp pH border formed between acidic and basic zones, moving toward the column outlet. Enriched metal ions are finally eluted with the sharp pH border as a highly concentrated peak into a volume of less than 100 microL. We evaluated this method for concentration efficiency in trace determination in tap water using different column diameters.

Countercurrent Distribution↗