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Biomedical subjects

A Segawa

Publications and source records attributed to A Segawa.

At least 19 recordsLinked to original sources
PubMed1995

Scintigraphic detection of xenografted renal tumor by anti-renal cancer monoclonal antibody radiolabeled with technetium-99m.

Accumulation in the tumor of the RCS-1 monoclonal antibody, which recognizes the cell surface antigen of renal cancer cells was examined. The antibody purified by affinity chromatography (protein-A column) and gel fractionation was labeled with technetium-99m (99mTc) by a direct method. High labeling efficiency (> 98%) could be routinely obtained. However, the 99mTc labeling of the antibody did not reduce the reactivity of the RCS-1 antibody. The labeled antibody was injected into nude mice transplanted with human renal and gastric tumors, and the accumulation of the antibody in each tumor and various tissues was compared at 48 hours after injection. The highest accumulation of radiolabeled RCS-1 antibody was observed in the AM-RC-3 renal tumors; at 8.0% of the injected dose per gram and a tumor-to-blood ratio of 1.05, respectively. However, the radiolabeled RCS-1, did not show specific accumulation in the gastric tumor nor in any tissues tested. The xenografted tumor, AM-RC-3 was successfully visualized with the radiolabeled RCS-1 antibody by scintigraphy.

Animals↗
PubMed1995

[Function of myoepithelial cells in salivary secretion: reevaluation of the expulsion theory].

Although myoepithelial cells have been suggested to provide the expulsive force to secrete saliva into the mouth, direct evidence to support this idea has been lacking. We examined the structure and distribution of myoepithelial cells in rat parotid and sublingual glands, and observed whether contraction occurs in living acini during secretion in vitro. Scanning electron microscopy and the whole mount alkaline phosphatase histochemistry revealed well-developed myoepithelial cells around the sublingual acini. In the parotid gland, myoepithelial cells were abundant along the intercalated ducts but were sparse around the acini. A stress fiber-like distribution of actin fibers was demonstrated by rhodamine phalloidin staining in the myoepithelial cells of sublingual glands. Under a video-enhanced microscope, a rapid shrinkage of sublingual acini was observed within 2 min of secretory stimulation. However, the shrinkage was slight and transient, and thereafter the acinar shape was almost maintained over 30 min, during which time considerable amounts of secretory granules were released. It was suggested that the major function of myoepithelial cells in salivary secretion is the support for the glandular structure through isometric contraction. This conclusion is compatible with our previous morphometric analyses on fixed cells (Noriko Shoi: Kitasato Med 24: 432-434, 1994).

Actins↗
PubMed1994

Development of enzyme-labeled oligonucleotide probe for detection of mecA gene in methicillin-resistant Staphylococcus aureus.

A DNA hybridization method with an enzyme-labeled oligonucleotide probe (mecA-ELONP) was developed to detect the methicillin-resistant gene (mecA) in methicillin-resistant Staphylococcus aureus. For rapid identification, bacterial colonies were transferred from agar plates directly onto nylon membranes. Lysis of cells, denaturation of DNA, and hybridization were performed on the membranes. These procedures required only 3 h for completion. The results obtained by this test closely corresponded with those obtained by determining the MICs of oxacillin against S. aureus. The results of the mecA-ELONP also correlated well with those of a commercially available PCR test. Thus, mecA-ELONP proved to be a reliable and convenient method for the rapid identification of methicillin-resistant S. aureus, which could be useful in clinical microbiology laboratories.

Bacterial Proteins↗
PubMed1994

Tight junctional permeability in living cells: dynamic changes directly visualized by confocal laser microscopy.

Confocal microscopy was used to study the tight junctional permeability in living rat parotid and submandibular glands. The interstitial space of the tissue was perfused with medium containing fluorescent tracers Lucifer Yellow (anionic: MW 457), Propidium Iodide (cationic: MW 668) and dextrans labeled with FITC or RITC (anionic and neutral: MW 3K, 10K, 40K, 70 K and 500 K) to monitor whether or not these tracers permeate into the lumen across the junction. In the acini of normal glands, fluorescence was detected in the basolateral space but not in the luminal space up to 30 min. However, when secretion was induced by isoproterenol or carbachol, fluorescence appeared in the luminal space within 2 to 5 min. This did not involve the disruptive changes in tight junction ultrastructure, nor was it irreversible; the luminal fluorescence disappeared again when the secretagogues were removed. Tracers up to MW 40 K for isoproterenol and MW 10 K for carbachol revealed the luminal fluorescence in parotid acini, with little indications of the charge preference characteristics. The luminal fluorescence also appeared by anoxia, enzymatic cell dissociation and the cytochalasin D treatment. It was suggested that the tight junctions in salivary acini dynamically alter their permeability and modulate the passage of large molecules through the paracellular pathway. Oxygen supply, extracellular matrices and cytoskeletons were suggested to influence these regulations.

Animals↗
PubMed1993

Isolation and characterization of mouse CD7 cDNA.

The human CD7 antigen is a glycoprotein, M(r) 40,000, expressed on the surface of peripheral blood T-lymphocytes and thymocytes, and is the earliest surface antigen to appear on T-cell lineage cells. In this study, putative mouse CD7 cDNA was identified based on its similarities with human CD7. Five independent clones originating from the same mRNA species were isolated (designated as mCD7) by screening a mouse thymocyte cDNA library with human CD7 cDNA, J61, under moderate stringency. The longest insert of a 995 base pair had an open reading frame of 210 amino acids. Northern blot analysis using the mouse CD7 cDNA probe demonstrated a single 1.2 kilobase mRNA in the thymus, spleen, bone marrow, and small intestine. The protein deduced from mCD7 cDNA consisted of the leader, extracellular, transmembrane, and cytoplasmic domains of 24, 126, 21, and 39 amino acids, respectively, based on the hydrophobicity plot and the structure of human CD7. The extracellular domain contained three potential N-glycosilation sites, while the cytoplasmic domain contained one potential protein kinase C phosphorylation site. The amino acid sequence had 45.5% similarity with human CD7, while the similarities for the individual domains ranged from 49.2% to 63.2%. The six highly conserved regions, which may possibly be involved with still unknown CD7-mediated functions, were located in the extracellular and cytoplasmic domains.

Amino Acid Sequence↗
PubMed1993

[Clinical study of renal cell carcinoma].

Previously, we reported the effects of human lymphoblastoid interferon (HLBI), using a transplantable human renal cell carcinoma strain (AM-RC-3) in nude mice established in our laboratory. An overall anticancer effect was found from its combination with UFT (Ft-207t uracil). In the present investigation, we examined the clinical effectiveness when HLBI was administered alone or in combination with UFT to the patients. Seventy-three patients who had undergone curative surgery were divided into 3 groups, according to the type of adjuvant therapy. The HLBI group consisted of 38 patients, including those administered the agent alone over 50 times for more than six months, and or those to whom it was given in combination with UFT. The second group of 23 patients had been treated with hormones, radiotherapy, or with an anticancer drug (Fluoride pyrimidine group), while the last group of 17 patients underwent no postoperative adjuvant therapy. The survival rate calculated by the Kaplan-Meier method revealed no significant effects of HLBI on the survival period, but a significant difference (p < 0.05) was found in the HLBI group compared to the other groups in terms of much higher non-recurrence rate. When HLBI was administered alone or in combination with UFT, a definite anticancer effect was seen in 6 (complete response 3, partial response 2, minor response (MR) 1, no change 5, progression of disease 14) of the 25 treated patients. Fourteen of the 25, treated patients had postoperative recurrence, and 11 patients had distant metastases, at the time of diagnosis which were considered to be progressive and measurable lesions. In 6 patients the response was better than MR, with the effective rate being 24%. Four of the 6 patients had received HLBI in combination with UFT, which suggests a clinical effect in this combination. However, the effectiveness was limited to the lung lesions, more effective treatment of the lesions in other sites is required.

Aged↗
PubMed1993

[Spindle cell carcinoma of the urinary bladder: a case report].

A 74-year-old man with spindle cell carcinoma of the urinary bladder is reported. He presented to our clinic with gross hematuria resulting in bladder tamponade. Transurethral resection (TUR) was performed in order to control severe hematuria intractable with conservative therapy. Histologically the tumor invaded the muscle layer and was composed of two components, small foci of transitional cell carcinoma and numerous spindle cells with severe atypia and then the transition was recognized between them. Immunohistochemically transitional cell carcinoma was intensely positive for cytokeratin (CK) and epithelial membrane antigen (EMA), but negative for vimentin (VIM). Moreover some parts of spindle cells were weakly stained for CK and EMA. Three months after TUR, multiple pulmonary metastases and moderate right hydronephrosis occurred and he died of respiratory insufficiency one month later.

Aged↗
PubMed1993

[The treatment of staghorn calculi].

Between May 1989 and November 1991, 19 staghorn calculi were treated by extracorporeal shock-wave lithotripsy (ESWL) with a Dornier MFL 5000 or Northgate SD-3. The 19 calculi were evaluated. Treatment was with monotherapy by ESWL in 9, combination percutaneous nephrolithotomy (PNL)-ESWL in 9, and nephrostomy in 1. Of the patients, 14 had a cross stent catheter pre-ESWL treatment to improve fragment evacuation. Radiologic follow up in 19 kidneys revealed that 57.9% were stone free. We arbitrarily separated our cases into 3 groups: struvite renal calculi, calcium carbonate calculi and others. Result of stone-free rate was 100% for stones consisting of struvite, and 14. 3% for stones consisting of calcium carbonate. In our opinion, the best indication of monotherapy by ESWL is for staghorn calculi, which consists of struvite, without marked dilation of pelvis and calyces.

Adult↗
PubMed1993

Confocal laser scanning microscopic and immunoelectron microscopic studies of the anatomical distribution of fibrillar IgA deposits in dermatitis herpetiformis.

BACKGROUND AND DESIGN: The fibrillar immunofluorescent pattern of IgA deposition in dermatitis herpetiformis is considered by most authorities to be a variant of the granular IgA pattern. It has been hypothesized that the fibrillar vs the granular pattern is related to longitudinal vs transverse sectioning of affected dermal microfibril bundles. However, direct evidence for this possibility has yet to be presented. Confocal laser scanning microscopy and immunoelectron microscopy were performed to determine the anatomical distribution of fibrillar IgA deposits, using skin specimens from a patient with typical fibrillar IgA deposition. OBSERVATIONS: Confocal laser scanning microscopy showed numerous fibrils stained with anti-IgA extending from the dermoepidermal junction to a depth of 50 to 110 microns in the dermis. They crossed each other at various angles to form a three-dimensional network. Immunoelectron microscopy demonstrated a diffuse dispersion of immune deposits on the surface of microfibrils of dermal microfibril bundles, with sporadic distribution of small aggregates, 0.1 to 0.3 micron in diameter. CONCLUSIONS: To our knowledge, this is the first article to present evidence for the actual distribution of fibrillar IgA. Insofar as the present case is concerned, the distribution of fibrillar IgA is greatly at variance with that indicated in previous reports on granular IgA. However, studies on more cases should be conducted to determine whether this is a distinctive feature of the fibrillar type of IgA deposition.

Dermatitis Herpetiformis↗
PubMed1993

[Clinical experience with extracorporeal shock wave lithotripsy using Dornier MFL 5000-(U) for urinary stone].

Our hospital recently installed one of the newest types of extracorporeal shock wave lithotripters, a Dornier MFL 5000-(U). We conducted preliminary clinical trials with the apparatus from April to June 1991. In this report we discuss our experience with the first 40 patients (52 stones) treated in a total of 52 extracorporeal shock wave lithotripsy (ESWL) sessions. Follow up observation was conducted for three months. Except in one case, invasive anesthesia was not used. A double J-catheter was inserted in 13 cases, a ureteral catheter in 7 cases, and percutaneous nephrolithotripsy (PNL) was used after ESWL in one case. After one month of follow-up, 27 patients (67.5%) were completely free from stone fragments, while at 3 months after treatment, 34 patients (85.0%) were free from stone fragments. No serious complications were observed after ESWL. We concluded that the Dornier MFL-5000-(U) apparatus is effective for renal and ureteral stones and generates no serious complications.

Adult↗
PubMed1992

[Three-dimensional reconstruction of cytoskeletons in rat salivary glands using confocal fluorescence microscopy and volume-rendering computer graphics].

A new reconstruction technique for the demonstration of three-dimensional architectural details from biological fluorescent specimens was used to determine the precise spacial organization of F-actin in rat sublingual glands. F-actin was stained with NBD-phallacidin in thick (20-30 microns) frozen sections and observed with a confocal laser scanning microscope to obtain thin (-1 micron) optically sectioned images. A series of optical sections taken successively at different focal levels in steps of 1 micron was then reconstructed with volume-rendering computer graphics. The rendered images viewed from several angles (e.g. top, bottom, sides) clearly revealed the presence of F-actin fluorescence along the hexagonal framework of the junctional complex within the acini and in the cytoplasm of star-shaped myoepithelial cells encircling the acini. The detailed structures and the topographical relations between the junctional complex and myoepithelial cells were more impressively observed when the rendered images were displayed by motion picture. These images are free from any artifacts caused by the mechanical sectioning and revealed well the delicate and complicated profiles of cellular structures that previously have been almost impossible to demonstrate by conventional reconstruction techniques. We expect that the combination of confocal microscopy and volume rendering will permit the dynamic observation of previously unseen phenomena in three dimensions, such as the behavior of biologically active molecules in living cells.

Animals↗
PubMed1991

Exocytosis in living salivary glands: direct visualization by video-enhanced microscopy and confocal laser microscopy.

Although exocytosis is widely believed to involve granule movement, membrane fusion and the emptying of granule content, direct study of these processes has been difficult in living cells because of the limited resolution of conventional light microscopy. Using video-enhanced microscopy and confocal laser microscopy, we have now studied these processes in living rat parotid and submandibular gland acinar cells. Under a differential interference contrast (DIC) microscope equipped with a CCD camera and a high speed image processor, secretory granules were in general stationary even after secretory stimulation with isoproterenol (IPR). Following IPR stimulation, however, there were abrupt changes in light intensity of secretory granules, and many granules disappeared. Confocal microscopy was then performed to confirm whether the observed changes in granules were related to membrane fusion and content release. For this, cells were perfused with the fluid-phase tracer Lucifer Yellow; confocal images thus obtained clearly demonstrated the appearance of fluorescence in omega-shaped invaginations of the apical plasma membrane which corresponded to the sites at which changes were observed in DIC images. The time sequence analyses of confocal images showed that there was a repetitive appearance and disappearance of omega-shaped fluorescent foci at the apical plasma membrane until most of the granules were depleted. During this time, there did not appear to be any significant expansion of the apical plasma membrane and if endocytic uptake of the tracer occurred, it was below the limit of detection. These observations provide new insights into the exocytotic process in salivary glands and are at variance in some respects with previous interpretations made from electron microscopy.

Animals↗
PubMed1990

[Radiation therapy for human renal cell carcinoma transplantable to the nude mice].

Efficacy of radiation therapy was studied using human renal cell carcinoma strain (AM-RC-3) implantable in nude mice. Cobalt 60 gamma-ray was used dosage of 5 Gy, 10 Gy, 15 Gy and 20 Gy in single, localized exposures of subcutaneously implanted tumors of the lower right femoral region. Therapeutic efficacy was determined using the Battelle Columbus Standard and evaluation of histological changes based on National Cancer Research Institute (Shimosato's classifications). Conclusion based on the obtained data are as follows: I) The T RW/C RW ratio on the tumor growth curve was 42% or less for all dosage groups except the 5 Gy group; dosages other than 5 Gy are believed effective. The 15 and 20 Gy dosage were particularly effective and the respective groups had RW of 0.96 and 0.95. II) Although Grade IIa and IIb changes were observed in the 15 and 20 Gy dosage groups, respectively, two weeks after irradiation, four weeks after irradiation all groups exhibited microscopic tissue formations that could be considered regrowth of tumor cells. Determination of histopathological effectiveness two weeks after irradiation is thought most suitable. III) Radiation therapy is appropriate as an adjuvant treatment in cases of renal cell carcinoma and should be used in combination with other therapies.

Animals↗
PubMed1990

Cyclic nature of poly(3-hydroxyalkanoate) metabolism in Alcaligenes eutrophus.

The cyclic process of biosynthesis and degradation of poly(3-hydroxyalkanoate) (PHA) was studied in Alcaligenes eutrophus under conditions of nitrogen-limitation of growth. A. eutrophus cells, which had accumulated poly(3-hydroxybutyrate) (PHB) of 55 wt% content within cells from butyric acid, were transferred into a nitrogen-free medium containing pentanoic acid as the sole carbon source and cultivated at 30 degrees C and pH 7.5. The content of PHB in A. eutrophus cells decreased with time, whereas a copolyester of 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV) units, P(HB-co-HV), was accumulated in the presence of pentanoic acid. Conversely, when A. eutrophus cells with 50 wt% content of P(HB-co-56% HV) were incubated in a nitrogen-free medium containing butyric acid, the content of P(HB-co-56% HV) decreased with time, whereas PHB was accumulated. These results indicate the cyclic nature of PHA metabolism in A. eutrophus under these conditions.

Alcaligenes↗
PubMed1990

Biosynthesis and characterization of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) in Alcaligenes eutrophus.

Copolyesters of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) were produced by Alcaligenes eutrophus at 30 degrees C in nitrogen-free culture solutions containing gamma-butyrolactone alone or with fructose or butyric acid as the carbon sources. When gamma-butyrolactone was used as the sole carbon source, the 4HB fraction in copolyester increased from 9 to 21 mol% as the concentration of gamma-butyrolactone in the culture solution increased from 10 to 25 g/l. The addition of fructose to the culture solution of gamma-butyrolactone resulted in a decrease in the 4HB fraction in copolyester. The copolyesters produced from gamma-butyrolactone and fructose by A. eutrophus were shown to have random sequence distribution of 3HB and 4HB units by analysis of the 125 MHz 13C n.m.r. spectra. In contrast, a mixture of random copolyesters with two different 4HB fractions was produced by A. eutrophus when gamma-butyrolactone and butyric acid were used as the carbon sources. These results are discussed on the basis of a proposed biosynthetic pathway of P(3HB-co-4HB). The copolyester films became soft with an increase in the 4HB fraction, and the elongation to break at 23 degrees C increased from 5 to 444% as the 4HB fraction increased from 0 to 16 mol%. The P(3HB-co-10% 4HB) film was shown to be biodegradable in an activated sludge.

Alcaligenes↗
PubMed1990

[Combination chemotherapy of human renal cell carcinoma in athymic nude mice with human lymphoblastoid interferon (HLBI) and UFT, 5-Fu].

The effectiveness of interferon alpha (HLBI) for nude mouse transplantable human renal cell carcinoma 72nd general meeting, in combination with UFT and 5-Fu, was examined using, 1 x 10(7) IU/kg, 2 x 10(7) IU/kg HLBI; 25 mg/kg 5-Fu; and 10 mg/kg, 20 mg/kg UFT, administered for 10 consecutive days. The ratio of relative mean tumor weight of treated group to control group was under 42% for the combination of 25 mg/kg (I.P.) 5-Fu, 20 mg/kg UFT, and HLBI and the effect was particularly clear for the combination with 2 x 10(7) IU/kg which indicated a grade IIA histologic classification. In comparison with the control groups only UFT (20 mg/kg) and HLBI (2 x 10(7) IU/kg) showed significant inhibition when administered alone. Although none of the drugs had an inhibitory effect when administered alone, in combined use they showed a strong antitumor effect which was more than synergistic. Orally administered 5-Fu showed a statistically significant difference only in the combination with 2 x 10(7) IU/kg HLBI. Furthermore, the concentration of 5-Fu in the tumor tissue was not affected by the route of administration or drug combination, whereas that in the serum was below the limit of detection in the intraperitoneally administered cases, 0.0096 +/- 0.0079 microgram/ml, lower than the value for orally administered cases. The 5-Fu concentration was 0.026 +/- 0.012 microgram/ml for orally administered UFT which was significantly higher than the value obtained for orally administered 5-Fu. Thus, combination therapy of HLBI and UFT for renal cell carcinoma is expected to be clinically useful.

Animals↗
PubMed1990

A clinical study of total cystectomy for transitional cell carcinoma of the urinary bladder.

Fifty six patients with transitional cell carcinoma of the urinary bladder were treated by total cystectomy from January, 1979 through December, 1988. A retrospective study was conducted on 52 patients on whom prognosis could be followed up. There were 40 men and 12 women (male to female ratio: 3.3: 1), between 32 and 79 years old (mean age, 64.1 years old). The overall 1-, 3- and 5-year survival rates were 65.8%, 54.1% and 43.0%, respectively. The 5-year survival rates for patients with low grade (G, I, II) and high grade (G. III) were 41.9% and 42.7%, respectively: with no significant difference in the survival curves between the two groups. The 5-year survival rates according to histopathological stage were 78.9% for patients in low stage, 24.7% in high stage, and the difference in the survival curves between the two groups was statistically significant (P less than 0.001). The mortality in the 21 cases of the 33 high stage cases in which cisplatin was used was 42.9%, with 3- and 5-year survival rates were 53.1% and 36.8%, respectively. In the remaining 12 cases in which cisplatin was not used for post-operative chemotherapy, the mortality in the 12 cases was 83.3%, with 3- and 5-year survival rates of 25.1% and 12.3%, respectively. Thus, the patients who received post-operative chemotherapy showed a better survival rate than those who did not with a significant difference (P less than 0.05). The results of the present study suggest the usefulness of post-operative adjuvant chemotherapy in the high stage case.

Adult↗