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Biomedical subjects

T Sawada

Publications and source records attributed to T Sawada.

At least 451 records · Page 25Linked to original sources
PubMed1995

Role of SPan-1 antigen in adhesion of human colon cancer cells to vascular endothelium.

Recently E-selectin (ELAM-1, endothelial leukocyte adhesion molecule-1) was shown to recognize not only sialyl Lewis X but also sialyl Lewis A, and these carbohydrate antigens may be involved in the process of the adhesion between cancer cells and endothelial cells in cancer metastasis. To investigate the contribution of sialylated carbohydrate antigen, SPan-1, and sialic acid to the adhesion of human colon cancer cells to endothelial cells, adhesion assay using HUVECs (human umbilical vein endothelial cells) was performed. The adhesion was significantly inhibited by pretreatment with anti-E-selectin antibody, indicating that this adhesion was thought to be mediated by E-selectin. When these cancer cells were pretreated with SPan-1 antibody, the adhesion was significantly inhibited in a concentration-dependent manner. The adhesion was also inhibited by pretreatment with neuraminidase. These findings suggest that the SPan-1 antigen plays a significant role in the adhesion of human colon cancer cells to endothelial cells, and sialylation of the terminal structure of carbohydrate antigens is important in this adhesion.

Antigens, Neoplasm↗
PubMed1995

Erythrocyte sodium-potassium transport in hyperkalaemic and normokalaemic infants.

UNLABELLED: One of the causes of early onset hyperkalaemia in very low birth weight infants is presumed to be the dysfunction of K+ transport across the cell membrane. Sodium-potassium adenosine triphosphatase(Na(+)-K+ ATPase) is known to play a major role in K+ transport. We compared the concentrations of erythrocyte Na(+)-K+ ATPase (Vmax levels) for hyperkalaemic and normokalaemic infants of matched gestational age. In hyperkalaemic infants, the highest levels of Vmax were reached at 24-48 h after birth, but in normokalaemic infants, there were no significant changes in Vmax levels during the 1st week after birth. At 12-72 h after birth, erythrocyte K+ concentrations for hyperkalaemic infants were higher than those of normokalaemic infants. For both groups of infants, the highest levels of plasma K+ during the 1st week after birth showed a positive correlation with those of Vmax. CONCLUSION: Na(+)-K+ ATPase on the cell membrane is activated to compensate for hyperkalaemia; however, when this compensation is incomplete, hyperkalaemia occurs.

Erythrocyte Membrane↗
PubMed1995

Laparoscopic-assisted colectomy and lymphadenectomy without peritoneal insufflation for sigmoid colon cancer patients.

PURPOSE: A new method for laparoscopic-assisted sigmoid colectomy and lymphadenectomy is presented. The purpose of this method is to avoid complications and restrictions associated with pneumoperitoneum. METHODS: Abdominal wall is lifted up with Kirschner wires, which are placed in the middle and left lower abdomen; then a minilaparotomy, which can be created because air-tightness is not necessary, is extended at the beginning of the operation to later remove the resected specimen. Two laparoscopic instruments are inserted through the right lower abdomen. Through the minilaparotomy, the surgeon can operate with conventional instruments. RESULTS: Operative time can be shortened, and surgical manipulations such as ligations and sutures are far easier than and cosmetic results are similar to those of laparoscopic surgery under pneumoperitoneum. CONCLUSION: We believe that this technique is a safe, time-saving, and cost-beneficial technique for sigmoid colectomy, and by changing the location of the minilaparotomy, this method can also be applied to other types of gastrointestinal surgery.

Abdominal Muscles↗
PubMed1995

Interleukin-6 stimulates cell proliferation of rat pituitary clonal cell lines in vitro.

We investigated the effect of recombinant human IL-6 (rhIL-6) on cell proliferation using the MtT/E rat pituitary tumor cell line, which was recently established by Inoue et al. This cell line expresses the homeodomain protein Pit-1/GHF 1 and does not produce any significant amount of pituitary hormones, but retains its tumorigenicity by back-transplantation into rats, resulting in production of prolactin. MtT/E cells were seeded into Falcon 24-well plates at a density of 2 x 10(4) cells/well in a cultured medium, containing 10% horse serum and 2.5% fetal bovine, with test drug. After four-days (12 days for the time-course study) incubations, the cells were counted using a hemocytometer. Incubation for 4 days with rhIL-6 caused concentration-dependent stimulation of MtT/E cell growth and [3H]-thymidine incorporation into MtT/E cells. Addition of 20 ng/ml rhIL-6 to the culture medium stimulated MtT/E cell growth in a time-dependent manner, withdrawal of rhIL-6 from the culture medium reduced MtT/E cell growth, and re-addition of rhIL-6 to the culture medium again stimulated MtT/E cell growth. Among the cytokines tested, granulocyte colony-stimulating factor (rh G-CSF) also showed a slight but significant mitogenic activity on the MtT/E cells. Analysis of 125I-rhIL-6 binding to the MtT/E cells indicated a dissociation constant of 0.953 x 10(-9) mmol/l and the presence of 968 binding sites per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Spatial distribution of enamel proteins and fibronectin at early stages of rat incisor tooth formation.

Enamel proteins are secreted very early during amelogenesis, that is prior to mantle dentine formation, raising the possibility that they may participate in epithelial-mesenchymal interactions taking place during tooth development. These first enamel proteins associate with elements of the basement membrane interposed between the differentiating ameloblasts and odontoblasts. Fibronectin, a component of the basement membrane, is redistributed and accumulates along the apical portion of odontoblasts during their terminal differentiation. In order to determine whether any correlation exists between the redistribution of fibronectin and the secretion of the first enamel proteins, the spatial distribution of these two extracellular matrix proteins was examined during the presecretory stage of amelogenesis. Male Wistar rats were perfused with a formaldehyde-based fixative, and undemineralized and EDTA demineralized incisors were dehydrated in methanol and embedded in Lowicryl K4M resin. Ultrathin tissue sections were then processed for post-embedding, colloidal-gold immunocytochemistry with antibodies to enamel proteins, fibronectin or type III collagen. In the region of ameloblasts facing pulp, labelling for fibronectin was weak and mostly associated with the lamina fibroreticularis of the basement membrane separating differentiating ameloblasts and odontoblasts. As the mantle predentine formed the immunoreaction for fibronectin increased, particularly in the region of the basement membrane. Enamel proteins were also immunodetected in association with the lamina fibroreticularis and gradually accumulated as patches within mantle dentine and at its interface with ameloblasts. Von Korff collagen bundles, present between odontoblasts and in dentine, were immunolabelled for fibronectin and for type III collagen. Patches of granular material, immunoreactive for fibronectin and/or enamel proteins, were found along the odontoblastic processes and cell bodies. Although no evidence was obtained indicating a precise colocalization of fibronectin and enamel proteins, the results confirm that these two proteins can be found within similar extracellular compartments during mantle predentine-dentine formation. These data suggest that enamel proteins, by themselves or synergistically with other proteins, may play a part in the differentiation and/or formative events taking place at the ameloblast-odontoblast interface during the early stages of tooth development.

Ameloblasts↗
PubMed1995

High glucose increases platelet-derived growth factor production in cultured human vascular endothelial cells and preventive effects of eicosapentaenoic acids.

The regulation of the production of platelet-derived growth factor (PDGF) and the influence of high glucose concentration, eicosapentaenoic acid (EPA) were studied in cultured human umbilical vein endothelial cells (HUE). The PDGF production of HUE increased markedly depending on glucose concentration. However, EPA (3 x 10(-4)M) markedly inhibited PDGF production [27.5 mM glucose group: 123 +/- 3% of control (5.5 mM glucose group), 27.5 mM glucose+EPA group: 104 +/- 5% of control]. These results suggested that a high glucose concentration and a high osmotic pressure-induced increase in PDGF production is involved in the development and progression of diabetic macroangiopathy. As eicosapentaenoic acid inhibits the PDGF production induced by high glucose concentration in HUE, use of this agent may exhibit anti-arteriosclerotic effects.

Cells, Cultured↗
PubMed1995

Restoration of myo-inositol uptake by eicosapentaenoic acid in human skin fibroblasts cultured in high-glucose medium.

The effects of elevated glucose and eicosapentaenoic acid (EPA, C20:5 omega 3) on myo-inositol uptake in human skin fibroblasts (HSF) were evaluated. Myo-inositol incorporation into HSF was dependent on an active transport system via Na(+)-K+ ATPase activity based on the results with Na+ deprivation and ouabain (5 mM). Although glucose (27.5, 55 mM) inhibited 2-[3H] myo-inositol uptake, the addition of EPA (3 x 10(-4) M) prevented glucose-mediated inhibition. Since EPA decreased glucose-mediated inhibition of myo-inositol uptake, this agent might ameliorate some of the devastating functions associated with diabetes.

Cells, Cultured↗
PubMed1995

Expression of insulin-like growth factor I mRNA in rat luteal tissue increases with functional regression of the corpus luteum.

The expression of insulin-like growth factor (IGF-I) messenger ribonucleic acid (mRNA) in rat corpora lutea (CL) was determined during the second half of pregnancy and early lactation, and the effect of prostaglandin F2 alpha on expression was examined during late pregnancy. Northern blot analysis revealed 4 species of transcripts in CL. Radioactivity of dot blots was measured directly for quantitative analysis of expression. The expression in CL increased during the second half of pregnancy, peaked around parturition, and declined thereafter. The injection of 1 mg of prostaglandin F2 alpha at 1300 and 1800 h on day 18 of pregnancy, which decreased plasma progesterone concentration, doubled luteal expression of IGF-I mRNA 1 day later. These results suggest that functional regression of the corpus luteum is correlated with the increased expression of IGF-I mRNA in luteal tissue in rats.

Animals↗
PubMed1995

Secretion of progesterone during long and short days of the estrous cycle in goats that are continuous breeders.

This study was conducted 1) to determine if the secretion of progesterone, as an index of ovarian activity, during the estrous cycle of nonseasonal Shiba goats is affected by seasonal changes, and 2) to learn if the pulsatile secretion of ovarian progesterone can be estimated from samples obtained by cannulation into the caudal vena cava via the femoral vein. Progesterone concentrations in jugular venous plasma during the estrous cycle in spring (May) were similar to those in autumn (November). Plasma progesterone concentrations in the jugular vein and caudal vena cava monitored for 10 h on Day 12 of the estrous cycle in spring were similar to those in autumn. The mean concentration (21.9 to 28.9 ng/ml) and the pulse frequency (6.2 to 7.4 pulses/10 h) of plasma progesterone in the caudal vena cava during both seasons were 3.1- to 4.7-fold and 1.7- to 2.4-fold those in the jugular vein, respectively. The degree of change in the peak magnitude and the base-line concentration of progesterone were higher in the caudal vena cava than in the jugular vein. These results indicate that progesterone secretion during the estrous cycle in nonseasonal goats is not affected by seasonal changes, and suggest that the pulsatile secretion of ovarian progesterone can be evaluated better from samples obtained from the caudal vena cava, near where progesterone is released, than from those obtained from the jugular vein.

Journal Article↗
PubMed1995

Immunohistochemical localization and biological significance of the phylogenically conserved thymus-brain antigen (UB-13 antigen) in skate, rat and human.

A monoclonal antibody (UB-13) originally raised against the brain of the skate (Raja kenojei, a cartilaginous-fish) was found to react with lymphoid and brain tissues from many species when examined immunohistochemically. In rat and human thymus, UB-13 antigen was observed to be closely associated with reticular tissue in the medulla and cortex. Interestingly, a few or several thymocytes were encircled by the UB-13-reactive reticular tissue. At 14 days gestation, rat thymus consisted mainly of reticular epithelial tissue, after which strong thymocyte production started. At this stage, some of the reticular tissue was heavily stained with UB-13. In the thymus tissues of the irradiated and recovering rats, where reduction and massive reproduction of thymocytes were observed, extensive UB-13 antigen expression localized on the reticular epithelial tissue, an observation which may support the thymocyte re-population. These findings suggest that the antigen recognized by UB-13 may be important for thymocyte proliferation and maturation. UB-13 antigen was found in the fibrous structure of the molecular and granular layer of the human cerebellum. Some glial cells were also stained strongly with UB-13 in the human cerebellar or cerebral grey and white matter. In rat, glial cells, especially astroglias, and the endothelial structure of blood vessels were stained strongly with UB-13. These findings suggest that UB-13 may be a useful monoclonal antibody for analysis of brain-lymphoid antigen in many species.

Adult↗
PubMed1995

Thyrotropin-releasing hormone in treatment of intractable epilepsy: neurochemical analysis of CSF monoamine metabolites.

The efficacy of thyrotropin-releasing hormone in children with intractable epilepsy was investigated and changes in cerebrospinal fluid monoamine metabolites were analyzed. The 18 patients had either West syndrome (12 patients) or Lennox-Gastaut syndrome (6 patients), which was intractable to antiepileptic drug therapy and to adrenocorticotrophic hormone. Thyrotropin-releasing hormone-tartrate was administered for 4 weeks. Before and after the thyrotropin-releasing hormone administration, cerebrospinal fluid was collected and analyzed for 5-hydroxyindoleacetic acid, kynurenine, homovanillic acid, and 3-methoxy-4-hydroxyphenyl glycol. The patients were classified into 3 groups, based on seizure frequency and electroencephalographic effects: cessation of seizures and seizure discharges (very effective; group A), reduction of seizures and/or seizure discharges (effective; group B), and no changes in frequency of seizures or discharges (not effective; group C). There were 6 patients in group A, 3 in group B, and 9 in group C. There were no significant differences in monoamine metabolites before and after the thyrotropin-releasing hormone therapy. A trial of thyrotropin-releasing hormone for the treatment of intractable epilepsy is warranted and further study is required on the mechanism of the antiepileptic action of thyrotropin-releasing hormone.

Child↗
PubMed1995

Establishment of a new human extrahepatic bile duct carcinoma cell line (OCUCh-LM1) and experimental liver metastatic model.

A new human extrahepatic bile duct carcinoma cell line, designated OCUCh-LM1, was established from a liver metastatic lesion in a 61-year-old male. OCUCh-LM1 cells proliferated in a monolayered sheet with a population doubling time of 31 h. OCUCh-LM1 cells had an aneuploid pattern with a DNA index of 1.76, and chromosome counts showed a unimode of 63. OCUCh-LM1 cells expressed various carbohydrate antigens, including sialyl Lewis X, carbohydrate antigen 19-9 and SPan-1 antigen. Subcutaneous injections of OCUCh-LM1 cells induced tumour formation in nude mice. The reconstituted tumours were classified as well-differentiated adenocarcinoma. A daughter line, designated OCUCh-LM1-H1, was also established from liver metastatic colonies induced by splenic injection of OCUCh-LM1. OCUCh-LM1-H1 cells showed a higher potential for liver metastasis than OCUCh-LM1 (100% vs 20%). Since OCUCh-LM1 retains the initial characteristics (as of 93 passages at present) and expresses various carbohydrate antigens, the OCUCh-LM1 cell line and liver metastatic model established here will be useful for the study of the biological nature of extrahepatic bile duct carcinoma and the relationship between the expression of carbohydrate antigens and metastatic potential.

Animals↗
PubMed1995

Microvessel quantitation in invasive breast cancer by staining for factor VIII-related antigen.

The clinical importance of microvessel quantitation as a prognostic indicator in invasive breast cancer was examined. This study included 155 patients with invasive breast cancer, with a median follow-up of 82 months. Microvessels were identified by immunohistochemical staining for factor VIII-related antigen in formalin-fixed, paraffin-embedded primary tumours. For each tumour, microvessels were counted within a 200 x magnification field in the area of highest microvessel density. Microvessel counts (MVCs) had no correlation with tumour size, lymph node status or histological grade. When patients were classified by MVC, higher counts were associated with shorter disease-free survival and overall survival (P < 0.025 and P < 0.01 respectively). Multivariate analysis showed that MCV is an independent prognostic factor. Microvessel quantitation may be a useful predictor for identifying breast cancer patients at high risk for relapse and death.

Breast Neoplasms↗
PubMed1995

Tumour angiogenesis and tumour cell proliferation as prognostic indicators in gastric carcinoma.

Tumour growth depends on neovascularisation and tumour cell proliferation. Factor VIII-related antigen (F-VIII RA) localises to vascular endothelium. Expression of proliferating cell nuclear antigen (PCNA) is correlated with cell proliferation. We investigated the correlation between the expression of these antigens and prognosis in gastric carcinoma. A total of 108 specimens resected from patients with gastric carcinoma were investigated by staining with monoclonal antibodies against F-VIII RA and PCNA. Microvessel count (MVC; the mean number of microvessels in the five areas of highest vascular density at 200 x magnification) and PCNA labelling index (PCNA LI; percentage of positive cells in more than 500 tumour cells) were determined. The results showed that prognosis was significantly worse in patients who had a tumour with a high MVC (16 or greater) or a high PCNA LI (42% or greater) than in those patients who had a tumour with a low MVC (less than 16) or a low PCNA LI (less than 42%). Furthermore, MVC was significantly associated with the risk of hepatic recurrence. In conclusion, both MVC and PCNA LI may be good prognostic indicators in patients with gastric carcinoma.

Adult↗
PubMed1995

Familial adenomatous polyposis: should patients undergo surveillance of the upper gastrointestinal tract?

Upper gastrointestinal (UGI) endoscopy was performed in 35 asymptomatic patients with familial adenomatous polyposis (FAP) to assess the prevalence of gastric and duodenal polyps and to demonstrate efficacy of endoscopic surveillance in patients with FAP. UGI polyps were found in 25 (71%) of 35 polyposis patients. Among these, gastric fundic gland polyps were involved in seven patients, and UGI adenomas in 18 patients; there were nine gastric adenomas and 14 duodenal adenomas, including six cases of duodenal cancer. UGI polyps were found in 13 of 15 patients with extracolonic manifestations (87%), but in only 12 of 20 patients (60%) without. The median follow-up interval was 8.7 years in growing duodenal adenomas, but 3.5 years in adenomas without changes in size and number. It was concluded that surveillance gastroduodenoscopy every 3-5 years might be enough to treat duodenal adenomas by endoscopic mucosal resection.

Adenomatous Polyposis Coli↗
PubMed1995

Establishment of novel lymphoid cell lines dually infected with human T cell lymphotropic viruses types I and II.

With the goal of establishing an in vitro system of dual infection with human T cell lymphotropic viruses (HTLV) types I and II, rabbit lymphocytes were cocultured with a mixture of lethally irradiated HTLV-I-producing Ra-1 and HTLV-II-producing RII cell lines. This gave rise to a lymphoid cell line, RW-1, that was dually infected with HTLV-I and -II as detected by immunofluorescence staining, electron microscopy, and polymerase chain reaction using primers specific for the pol and env regions of each virus and by Southern blot hybridization. Two clonal cell lines derived from RW-1 were also coinfected with the viruses, indicating that dual infection had occurred at the single cell level. The coinfection could be readily propagated to fresh lymphocytes by coculture with RW-1. In contrast, attempts to superinfect HTLV-I-infected lymphoid cell lines with HTLV-II and vice versa were consistently unsuccessful, suggesting receptor interference between HTLV-I and -II.

Animals↗
PubMed1995

Intratumoral injection of an adriamycin immunoconjugate against human pancreatic cancer xenografts.

We have evaluated the effect of an adriamycin conjugate of monoclonal antibody Nd2 (ADM-Nd2) on the growth rate of SW1990 xenografts grown subcutaneously in athymic nude mice. Intravenous or intraperitoneal administration of radiolabeled Nd2 resulted in a maximum tumor accumulation of approximately 45% of the initial dose/g of tumor 3-7 days after administration. However, administration into the tumor produced retention of 1200%ID/g 1 day after, with 50% of this high value remaining even at 7 days after administration. In contrast, intratumoral administration of a non-specific immunoglobulin showed a lower initial retention and rapid loss of label. Both intravenously and intratumorally administered ADM-Nd2 reduced the growth rate of SW1990 xenografts. While a single intravenous administration arrested growth for about two weeks, a single intratumoral injection prevented any increase in tumor size even 45 days after administration. Xenografts treated with ADM-Nd2 showed degenerative changes at the histological level. Neither Nd2 alone nor Adriamycin alone inhibited growth when administered at the same dose as the conjugate.

Animals↗