Biomedical subjects

S Yoshida

Publications and source records attributed to S Yoshida.

At least 181 records · Page 10Linked to original sources

PubMed2001

Immunoelectron microscopic study of PECAM-1 expression on lymphatic endothelium of the human tongue.

The expression of platelet-endothelial cell adhesion molecule-1 (PECAM-1) on lymphatic and blood vessels of the human tongue was examined with fluorescence and transmission electron microscopy (TEM). The study used anti-desmoplakins antiserum for light microscopic identification of the lymphatic vessels, plus a pre-embedding immunogold electron microscopic technique for TEM observations. Before making TEM observations, cryostat serial sections were immunostained with anti-desmoplakins or anti-PECAM-1 and then embedded. Semithin sections from each cryostat section were photographed under a light microscope and compared in order to identify the lymphatic vessels expressing PECAM-1. In fluorescence microscopy, PECAM-1 expression on lymphatic vessels was weaker than that on blood vessels. TEM observations showed that PECAM-1 expression on the blood vessels was observed only on the luminal surface of the endothelium. In lymphatic vessels, PECAM-1 expression was found both on the luminal and abluminal surfaces of the endothelium. The density of the PECAM-1 reaction products was lower in lymphatic vessels than in blood vessels. The density of PECAM-1 reaction products on the luminal surface of lymphatic vessels was higher than on the abluminal surfaces. The results suggest that blood vessels are more active than lymphatic vessels in leukocyte migration. The expression of PECAM-1 on the abluminal surface of lymphatic endothelium may allow leukocytes to adhere to the endothelium and interact in their migration from tissue into lymphatic vessels.

Endothelium, Lymphatic↗

PubMed2001

New endoscopic treatment for intramucosal gastric tumors using an insulated-tip diathermic knife.

BACKGROUND AND STUDY AIMS: For one-piece resection the conventional technique of endoscopic mucosal resection (EMR) is limited to gastric mucosal tumors of 10 mm or less in size. In this retrospective study, we investigated the efficacy and complications associated with a new EMR method, using an insulated-tip diathermic knife (IT-EMR). PATIENTS AND METHODS: In a total of 41 patients gastric mucosal tumors were resected using IT-EMR. RESULTS: One-piece resection rates were 82% (14/17) for lesions of 10 mm or less, 75% (12/16) for those between 11 and 20 mm, and 14% (1/7) for those of over 20 mm. Complication rates for severe bleeding and perforation were 22% and 5%, respectively. With a median follow-up period of 32 months, no recurrence was observed after these procedures. CONCLUSIONS: Compared with conventional EMR, this new method may have significant benefits, particularly regarding one-piece resection of lesions between 11 and 20 mm in size, and may also have a lower recurrence rate.

Adenocarcinoma↗

PubMed2001

Assessment of colorectal lesions using magnifying colonoscopy and mucosal dye spraying: can significant lesions be distinguished?

BACKGROUND AND STUDY AIMS: Assessing the nature of lesions at the time of colonoscopy is important, and magnifying colonoscopy allows examination of mucosal crypt patterns. In this study, we assessed mucosal crypt patterns to see whether we could predict the histological findings. PATIENTS AND METHODS: This retrospective study of total colonoscopy using magnifying colonoscopy involved 4445 patients between December 1993 and July 1998 at the National Cancer Center Hospital East. The mucosal crypt patterns of 3438 lesions were observed under magnifying colonoscopy with 0.2% indigo carmine solution, and classified according to a modified Kudo classification (type I to V). After endoscopic or surgical resection (3291 cases and 147 cases, respectively), histopathological examination was performed. RESULTS: The diagnostic accuracy of magnifying endoscopy for non-neoplastic lesions was 75% (117/157), for adenomatous polyps it was 94% (3006/3186), and for invasive carcinomas it was 85 % (81/95). CONCLUSIONS: The combination of magnifying colonoscopy and dye spraying is helpful in determining the nature of colonic lesions as non-neoplastic, adenomas, or invasive carcinomas. Therefore it may be possible to determine, at the time of colonoscopy, which lesions require no treatment, which can be removed endoscopically, and which should be removed by surgery.

Adenocarcinoma↗

PubMed2001

Metastatic tumors to the stomach: analysis of 54 patients diagnosed at endoscopy and 347 autopsy cases.

BACKGROUND AND STUDY AIMS: There have been several published reports on metastatic lesions in the stomach, but the numbers of cases have been limited due to the low frequency of the condition. The present study examined the clinicopathological features of metastatic tumors in the stomach from distant sites in a large series of cases. PATIENTS AND METHODS: A total of 389 patients with gastric metastases from solid malignant tumors were examined between 1968 and 1998 at our institution. Of these, 347 were identified from a series of 6380 autopsy cases; 54 patients were diagnosed endoscopically while alive, 12 of whom had confirmation of the condition at autopsy. RESULTS: In the endoscopically diagnosed cases, the metastases presented as solitary (65%) or multiple lesions (35 %), and were more frequently located in the middle or upper third of the stomach. Although the endoscopic appearance often resembled that of submucosal tumor (51%) or primary gastric cancer (39%), the final diagnosis was easily obtained in over 90% of cases from endoscopic biopsies. In two cases of lung cancer and breast cancer, gastric metastases were found before the primary tumors. In the autopsy cases with solid malignancies, metastatic lesions to the stomach were found in 5.4%, and the lung, breast, and esophagus were common primary sites. Malignant melanoma was the most frequent tumor to metastasize to the stomach (29.6%). CONCLUSIONS: Since metastatic lesions to the stomach are rare, the above characteristics of the lesions should be borne in mind, and biopsies should be taken for precise diagnosis during endoscopic examinations.

Adult↗

PubMed2001

A new endoscopic tattooing technique for identifying the location of colonic lesions during laparoscopic surgery: a comparison with the conventional technique.

BACKGROUND AND STUDY AIMS: Knowledge of the exact location of colorectal lesions is necessary but difficult to establish during surgery. Thus, endoscopic tattooing has been used as an important preoperative marker for identification. Using the conventional technique, we injected tattooing agents directly into the colonic wall. However, to make sure that the tattooing agents were adequately injected into the submucosal layer, and to prevent spillage into the peritoneal cavity, we modified the conventional method and developed a new tattooing technique: using India ink with prior and subsequent injection of saline into the submucosa. The aim of this study was to retrospectively assess the clinical utility and potential complications of the above two techniques of endoscopic tattooing using India ink. PATIENTS AND METHODS: A total of 153 patients underwent laparoscopically assisted colectomy at the National Cancer Center Hospital East, Kashiwa, Chiba, Japan, between June 1994 and December 1999, and 91 patients underwent preoperative endoscopic tattooing by either the conventional or the new technique. The conventional and new techniques were used from June 1994 to December 1997 (n = 36) and from January 1998 to December 1999 (n = 55), respectively. Informed consent was obtained from all the patients. RESULTS: Using the conventional technique, the exact location of the lesion was identified in 31 of 36 cases (86.1 %) during surgery. The complications of this procedure were silent local peritonitis in two patients and reactive lymph node swelling in one patient (3/36, 8.3 %). Using the new technique, in 54 of 55 cases lesions (98 %) were easily identified (p = 0.034),and in only one there was a small leakage of India ink into the peritoneal cavity (1/55; 1.8 %), no other serious complications were observed. CONCLUSIONS: The results demonstrate that our new technique for endoscopic tattooing is probably better than the conventional technique for clinical use, in terms of diagnostic accuracy and safety, but this would have to be proven in a randomized comparison.

Carbon↗

PubMed2001

A 0.8-mm depressed adenoma of the colon with high-grade dysplasia.

Flat and depressed cancers of the colon have now been recognized in several centers throughout the world. We report here a case of a 0.8-mm depressed adenoma with high-grade dysplasia in a 70-year-old man. We believe this to be the smallest adenoma ever reported, and unusually (for a small lesion) it was positive for the K-ras mutation.

Adenoma↗

PubMed2001

Sodium thiosulfate solution spray for relief of irritation caused by Lugol's stain in chromoendoscopy.

BACKGROUND: Mucosal iodine staining is known to improve the endoscopic visualization of esophageal squamous dysplasia and cancer. However, it often causes mucosal irritation leading to retrosternal discomfort. The clinical usefulness of sodium thiosulfate solution (STS) for easing symptoms induced by mucosal staining with Lugol's solution was evaluated in this study. METHODS: One hundred twenty healthy men over 50 years of age were enrolled in the study. They each underwent esophagogastroscopy including the spraying of Lugol's iodine solution (10 mL) on the mid and distal esophagus and were subsequently randomized into three groups: (I) no treatment (n = 40), (II) spraying of 20 mL of aluminum-magnesium hydroxide gel (Maalox) by means of endoscopic catheter (n = 40), and (III) spraying of 20 mL of 5% sodium thiosulfate solution by means of endoscopic catheter (n = 40). An hour after the endoscopic examination the subjects were asked to complete a questionnaire that addressed adverse symptoms induced by Lugol's iodine staining. RESULTS: Sodium thiosulfate solution spray substantially reduced adverse symptoms that lasted more than 30 minutes after chromoendoscopy, compared with the no-treatment group. There was no significant difference in the proportion of subjects with symptoms between the Maalox and no-treatment groups. Cost of sodium thiosulfate solution spray per use was $0.15 (15 yen). CONCLUSIONS: Sodium thiosulfate solution is recommended for routine use after Lugol's staining.

Coloring Agents↗

PubMed2001

Interleukin-6 (IL-6) production by cytokine-stimulated human Müller cells.

PURPOSE: To investigate whether or not human Müller cells synthesize interleukin (IL)-6. METHODS: Using RT-PCR, we first confirmed whether cultured human Müller cells express IL-6 mRNA. Then, to determine Müller cell IL-6 production after stimulation, cultured Müller cells were exposed to various concentrations of IL-1beta (0.2 ng/ml, 2 ng/ml, 20 ng/ml) or lipopolysaccharide (LPS) (0.001 microg/ml, 0.1 microg/ml, 10 microg/ml) in 24 hr assays. In addition, to determine Müller cell time-dependent induction of IL-6 production, cultured Müller cells were exposed to IL-1beta (0.02 ng/ml, 2 ng/ml) or LPS (10 microg/ml) for 6, 12, 24, 36 hr. IL-6 production in supernatants was quantified by ELISA: RESULTS: IL-6 mRNA was expressed in cultured human Müller cells, which produced IL-6 after stimulation with either IL-1beta or LPS for 24 hours. IL-1beta was a significantly more potent stimulator of IL-6 production than was LPS. Exposure of cultured human Müller cells to either IL-1beta or LPS stimulated IL-6 production in a time-dependent fashion. CONCLUSIONS: Our findings indicate that human Müller cells can produce IL-6 when stimulated by IL-1beta or LPS. Müller cell IL-6 production may have an important role in various conditions involving ocular inflammation

Cell Division↗

PubMed2001

Microtubules and actin cytoskeleton in Cryptococcus neoformans compared with ascomycetous budding and fission yeasts.

Actin cytoskeleton and microtubules were studied in a human fungal pathogen, the basidiomycetous yeast Cryptococcus neoformans (haploid phase of Filobasidiella neoformans), during its asexual reproduction by budding using fluorescence and electron microscopy. Staining with rhodamine-conjugated phalloidin revealed an F-actin cytoskeleton consisting of cortical patches, cables and cytokinetic ring. F-actin patches accumulated at the regions of cell wall growth, i. e. in sterigma, bud and septum. In mother cells evenly distributed F-actin patches were joined to F-actin cables, which were directed to the growing sterigma and bud. Some F-actin cables were associated with the cell nucleus. The F-actin cytokinetic ring was located in the bud neck, where the septum originated. Antitubulin TAT1 antibody revealed a microtubular cytoskeleton consisting of cytoplasmic and spindle microtubules. In interphase cells cytoplasmic microtubules pointed to the growing sterigma and bud. As the nucleus was translocated to the bud for mitosis, the cytoplasmic microtubules disassembled and were replaced by a short intranuclear spindle. Astral microtubules then emanated from the spindle poles. Elongation of the mitotic spindle from bud to mother cell preceded nuclear division, followed by cytokinesis (septum formation in the bud neck). Electron microscopy of ultrathin sections of chemically fixed and freeze-substituted cells revealed filamentous bundles directed to the cell cortex. The bundles corresponded in width to the actin microfilament cables. At the bud neck numerous ribosomes accumulated before septum synthesis. We conclude: (i) the topology of F-actin patches, cables and rings in C. neoformans resembles ascomycetous budding yeast Saccharomyces, while the arrangement of interphase and mitotic microtubules resembles ascomycetous fission yeast Schizosaccharomyces. The organization of the cytoskeleton of the mitotic nucleus, however, is characteristic of basidiomycetous yeasts. (ii) A specific feature of C. neoformans was the formation of a cylindrical sterigma, characterized by invasion of F-actin cables and microtubules, followed by accumulation of F-actin patches around its terminal region resulting in development of an isodiametrical bud.

Actin Cytoskeleton↗

PubMed2001

Extracorporeal ultrasound is an effective diagnostic alternative to endoscopic ultrasound for gastric submucosal tumours.

BACKGROUND: Although endoscopic ultrasonography (EUS) is the best modality in the diagnosis of gastric submucosal tumours (G-SMT), it is still invasive and expensive. We evaluated the usefulness of transabdominal ultrasonography (US) as an alternative to EUS in the assessment and clinical management of G-SMT. METHODS: This is a prospective study of 156 successive patients who had been diagnosed with G-SMT by direct endoscopic visualization. For each patient, US was performed prior to EUS by an examiner who had not been informed about the site or the size of the patient's G-SMT beforehand. US diagnoses were compared with those ascertained by EUS. Diagnostic grade by US was divided into three groups: diagnosed (G-SMT was clearly demonstrated including location, site and type), detected (G-SMT was demonstrable but the type was not clear) and undetected (G-SMT was not demonstrated by US). RESULTS: We found that US can be an alternative to EUS for: 1) diagnosis of extramural compression, 2) diagnosis of G-SMT with size >30 mm in diameter, 3) detection and measurement of the size of a G-SMT from 21 to 30 mm in diameter, and 4) detection and measurement of the size of a G-SMT at both the gastric angle and cardia, regardless of the size of the tumour. Overall sensitivity and specificity for the detection of G-SMT were 82.5% and 100%, respectively. The diagnostic rates of G-SMT in each group were 60.1% (86/143) for diagnosed, 22.4% (32/143) for detected and 17.5% (25/143) for undetected. Approximate 95% (21/22) of G-SMT over 20 mm in diameter were at least detected, and 97% (30/31) of G-SMT over 30 mm in diameter were diagnosed by US. CONCLUSION: US can be an alternative method in the assessment of G-SMT, especially in the follow-up of patients already diagnosed.

Adolescent↗

PubMed2001

Analyses of muscular activity, energy metabolism, and muscle fiber type composition in a patient with bilateral masseteric hypertrophy.

Hyperwork of the masseter muscles due to habitual parafunction is thought to induce masseteric hypertrophy (so called work hypertrophy). However, the causes underlying this disease are not yet fully understood. Recently, we had a patient with bilateral masseteric hypertrophy, and we performed a partial excision of the masseter muscles. In this patient's case, we examined muscular activity, energy metabolism, and fiber type composition of the masseter muscles using electromyograms (EMG), 31P-magnetic resonance spectroscopy (MRS), and enzyme-histochemistry. The EMG showed no hyperactivity, and the 31P-MRS showed normal energy spectral patterns and PCr contents of the masseter muscles. The fiber type composition, however, in the muscles in this case was very different from that in muscles with "work hypertrophy" and also that in normal masseter muscles: 1. Loss of type IIB fibers; 2. Increases in type IIA and in type IM & IIC fibers; and 3. Decrease in type I fibers. The findings suggest that this is not a case of work hypertrophy but a case of compensatory hypertrophy possibly due to a lack of high-tetanus-tension type IIB fibers.

Adenosine Triphosphate↗

PubMed2001

Self-expandable metallic stents for patients with recurrent esophageal carcinoma after failure of primary chemoradiotherapy.

BACKGROUND: Recent advances in chemoradiotherapy for esophageal carcinoma have resulted in improved survival rates. However, there are few options for recurrent dysphagia due to refractory carcinoma after failure of primary chemoradiotherapy. The aim of this study was to evaluate the safety and efficacy of self-expandable metallic stent placement for patients with recurrent esophageal carcinoma where definitive chemoradiotherapy has failed. METHODS: Thirteen consecutive patients with recurrent squamous cell carcinoma of the esophagus, in whom self-expandable metallic stents were placed after failure of primary chemoradiotherapy, were studied retrospectively. All patients had esophageal obstruction or malignant fistula. RESULTS: The oral alimentation status of nine of 13 patients (69%) improved after successful placement of the stent. Following placement of the stent, fever (>38 degrees C) and severe chest pain occurred in 85% (11/13) of the patients. In all patients examined, C-reactive protein was elevated within 1 week of the operation. Esophageal perforation occurred in three patients. Stent-related mediastinitis and pneumonia developed in six (46%) and three (23%) patients, respectively. Seven of the 13 patients (54%) died of stent-related pulmonary complications. CONCLUSION: Although the placement of a self-expandable metallic stent for patients with recurrent esophageal carcinoma after failure of chemoradiotherapy improved their oral alimentation status, we found that this treatment increases the risk of life-threatening pulmonary complications.

Adult↗

PubMed2001

Retrospective study of hyponatremia in gastric cancer patients treated with a combination chemotherapy of 5-fluorouracil and cisplatin: a possible warning sign of severe hematological toxicities?

BACKGROUND: Some anti-neoplastic agents induce hyponatremia. The relationship between hyponatremia and other toxicities in gastric cancer patients treated with 5-fluorouracil and cisplatin (FP) was investigated retrospectively to clarify its clinical significance. METHODS: The subjects were 50 advanced gastric cancer patients treated with FP. Patients' performance status, oral intake, nausea/vomiting, diarrhea, fever, urine volume, presence of ascites or pleural effusion, laboratory data and administration of diuretics, corticosteroid and contents and volume of hydration before and during the first 5 days after chemotherapy were reviewed. RESULTS: The serum sodium level decreased after initiation of chemotherapy in all patients and the lowest level (nadir) was most frequently observed on day 8 (range, days 2-14), which preceded hematological toxicities. In 10 patients (20%) the nadir of serum sodium was lower than 125 mEq/l. We classified these 10 patients as a low-sodium group and the others into a normal-sodium group. Six (60%) and seven (70%) of the 10 patients in the low-sodium group had complications with grade 3 or 4 leukopenia and thrombocytopenia, whereas only one (3%) and two (5%) were seen in the normal-sodium group (p < 0.0001). Stomatitis and diarrhea were also slightly more severe in the former than the latter group. With respect to sensitivity and probability, receiver operating characteristic curves showed the nadir ((> or = ) or <125 mEq/l) of the serum sodium level was the best marker for both leukopenia and thrombocytopenia. CONCLUSION: Hyponatremia after initiation of chemotherapy with FP may be a warning sign of subsequent severe hematological toxicity.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2001

Budding of fowlpox and pigeonpox viruses at the surface of infected cells.

Chick embryo fibroblasts and chorioallantoic membranes infected with fowlpox virus (FWPV) or pigeonpox virus (PPV) were examined by transmission and scanning electron microscopy. Immature virus particles were observed in finely granular areas, i.e. virus factories, of the cytoplasm. These particles had various forms depending on their stages of development. Many tubular structures were also seen in these regions. Mature virus particles with ellipsoidal or brick-shaped forms enclosing electron-dense cores were detected throughout the cytoplasm. Notably, there was a high frequency of virus budding at the cell surface, but only occasional virus wrapping in the cytoplasm. Another remarkable feature of the infected cells was accumulation of many virions just beneath the plasma membrane, indicating that this phenomenon is closely related to virus budding. Based on the observed frequency of budding, this mechanism seems to be the predominant way for FWPV and PPV to exit the cell.

Animals↗

PubMed2001

Menstrual cycle-specific inhibition of endometrial stromal cell proliferation by oncostatin M.

We have investigated the possible roles of oncostatin M (OSM), which is a member of the interleukin-6 family of cytokines, in endometrial and endometriotic stromal cell growth. Endometrial and endometriotic stromal cells were collected from the uterus or ovarian chocolate cysts. We observed the expression of mRNA transcripts for OSM, OSM receptor subunit beta, leukaemia inhibitory factor receptor subunit (LIFR), and glycoprotein 130 in endometrial and endometriotic stromal cells. We also examined the effects of OSM (0-50 ng/ml) and LIF (0-10 ng/ml) on endometrial and endometriotic stromal cell proliferation and evaluated the effects of OSM on endometrial stromal cell differentiation. The presence of 10-50 ng/ml OSM significantly suppressed endometrial stromal cell growth in secretory phase tissue but not in proliferative phase tissue. In contrast, stromal cells in endometriotic tissues were resistant to the inhibitory effects of OSM. Addition of LIF did not influence the growth of endometrial stromal cells. We also showed that 10 ng/ml OSM stimulated markers of differentiation causing increased prolactin secretion and cyclooxygenase-2 gene expression in endometrial stromal cells from the secretory phase. These results suggest that OSM may play a pivotal role in regulating the growth and differentiation of endometrial cells. Endometriotic cells may behave differently from normal endometrial cells in terms of the inhibitory response to OSM.

Antigens, CD↗

PubMed2001

The carboxyl terminal sequence of nucleolar protein B23.1 is important in its DNA polymerase alpha-stimulatory activity.

The protein B23 is a major nucleolar phosphoprotein comprising two isoforms, B23.1 and B23.2, which differ only in their carboxyl-terminal short sequences, the N-terminal 255 residues being identical in both forms. Both B23.1 and B23.2 stimulated immunoaffinity-purified calf thymus DNA polymerase alpha in a dose-dependent manner. The stimulatory effect of protein B23.1, the longer isoform, was found to be 2-fold greater than that of B23.2. Purified DNA polymerase alpha bound tightly to a protein B23.1-immobilized column, while it bound weakly to a protein B23.2-immobilized column. Surface plasmon resonance studies by BIAcore further showed that protein B23.1 bound to the DNA polymerase alpha-(dA).(dT) complex more tightly than did protein B23.2. The protein B23 isoforms appear to interact directly with the DNA polymerase alpha protein and not through the bound nucleic acid. These observations indicated that protein B23 physically bound to the DNA polymerase alpha and stimulated the enzyme activity. Product analyses showed that protein B23 greatly enhanced the reaction both in amount and length of product DNA, whereas it did not significantly alter the processivity of polymerization. In contrast, protein B23 effectively protected DNA polymerase alpha from heat inactivation. These results suggest that protein B23 stabilizes DNA polymerase alpha that is detached from product DNA, allowing the enzyme to be recruited for further elongation. Moreover, experiments using various C-terminal deletion mutants of protein B23 indicated that 12 amino acids at the C-terminal end of B23.1, which are absent in B23.2, may be essential for the full stimulation of the DNA polymerase alpha.

Amino Acid Sequence↗

PubMed2001

Isolation and RNA gel blot analysis of genes that could serve as potential molecular markers for leaf senescence in Arabidopsis thaliana.

Nine cDNAs, representing genes in which the transcripts accumulated in senescent leaves of Arabidopsis thaliana, were isolated by differential display reverse transcription polymerase chain reaction (DDRT-PCR) and the genes were designated yellow-leaf-specific gene 1 to 9 (YLS1-YLS9). Sequence analysis revealed that none of the YLS genes, except YLS6, had been reported as senescence-up-regulated genes. RNA gel blot analysis revealed that the transcripts of YLS3 accumulated at the highest level at an early senescence stage, whereas the transcripts from the other YLS genes reached their maximum levels in late senescence stages. Transcripts of YLS genes showed various accumulation patterns under natural senescence, and under artificial senescence induced by darkness, ethylene or ABA. These expression characteristics of YLS genes will be useful as potential molecular markers, which will enhance our understanding of natural and artificial senescence processes.

Abscisic Acid↗

PubMed2001

Brassinazole, an inhibitor of brassinosteroid biosynthesis, inhibits development of secondary xylem in cress plants (Lepidium sativum).

Brassinazole (Brz) is a specific brassinosteroid biosynthesis inhibitor. Cress plants (Lepidium sativum) grown in medium containing Brz exhibited a slight predominance of phloem differentiation at the expense of xylem differentiation and remarkable inhibition of the development of secondary xylem. This result indicates that brassinosteroids function in xylem development in vivo.

Arabidopsis↗