Biomedical subjects
Y Shirai
Publications and source records attributed to Y Shirai.
Immunocytochemical localization of serotonin and serotonin transporter (SET) in taste buds of rat.
We used an immunocytochemical approach to study the localization of serotonin and its termination system, serotonin transporter (SET), in the taste buds of rats using specific antibodies against serotonin and SET. Under confocal laser scanning microscopy, both serotonin and SET immunoreactivity were detected in the taste buds of rat vallate papillae. Serotonin immunoreactivity was seen in the spindle-shaped cells with apical processes that seemed to be light (Type II) taste cells. SET-immunoreactivity was mainly localized in the periphery or interfaces between the taste cells. Double staining studies revealed that all serotonin-containing taste cells were immunoreactive for SET, while a subclass of SET-positive cells showed serotonin immunoreactivity. These data support the hypothesis that serotonin plays a transmitter role in taste receptor cells and suggest that the serotonin-induced sensation of taste is terminated by serotonin uptake through serotonin transporter.
Effect of extracellular calcium concentrations on osteoclast differentiation in vitro.
We have been researching with the purpose of understanding the hard organization mineralization-suppression mechanism under a low calcium environment. So far, we have discerned clearly that the femur of an incubated newborn rat under a low calcium environment will develop bone formation dyscrasia such as hypertrophy of the caput. In this experiment, MC3T3-E1 (E1) cells, which are osteoblast-like cells, and mouse bone marrow were incubated in a coculture system under a low calcium environment and manifestation of osteoblast cells and their ability to resorb were examined. The results suggested that as the calcium concentration in the medium decreased manifestation of osteoclast cells increased, and as the degree of mineralization of E1 cells advanced, the number of manifestation of osteoblast cells decreased. We, therefore, report that there is a possibility that extracellular calcium concentrations involve the process of differentiation of bone marrow cells into osteoblast cells.
Regulation of nuclear translocation of forkhead transcription factor AFX by protein kinase B.
The regulation of intracellular localization of AFX, a human Forkhead transcription factor, was studied. AFX was recovered as a phosphoprotein from transfected COS-7 cells growing in the presence of FBS, and the phosphorylation was eliminated by wortmannin, a potent inhibitor of phosphatidylinositol (PI) 3-kinase. AFX was phosphorylated in vitro by protein kinase B (PKB), a downstream target of PI 3-kinase, but a mutant protein in which three putative phosphorylation sites of PKB had been replaced by Ala was not recognized by PKB. In Chinese hamster ovary cells (CHO-K1) cultured with serum, the AFX protein fused with green fluorescence protein (AFX-GFP) is localized mainly in the cytoplasm, and wortmannin induced transient nuclear translocation of the fusion protein. The AFX-GFP mutant in which all three phosphorylation sites had been replaced by Ala was detected exclusively in the cell nucleus. AFX-GFP was in the nucleus when the cells were infected with an adenovirus vector encoding a dominant-negative form of either PI 3-kinase or PKB, whereas the fusion protein stayed in the cytoplasm when the cells expressed constitutively active PKB. In CHO-K1 cells expressing AFX-GFP, DNA fragmentation was induced by the stable PI 3-kinase inhibitor LY294002, and the expression of the active form of PKB suppressed this DNA fragmentation. The phosphorylation site mutant of AFX-GFP enhanced DNA fragmentation irrespective of the presence and absence of PI 3-kinase inhibitor. These results indicate that the nuclear translocation of AFX is negatively regulated through its phosphorylation by PKB.
Immunohistochemical detection of lymph node micrometastases from gallbladder carcinoma using monoclonal anticytokeratin antibody.
BACKGROUND: The objective of this study was to define the sensitivity and clinical implications of the immunohistochemical detection of lymph node micrometastases in patients with gallbladder carcinoma (GBC). METHODS: The authors examined a total of 385 regional lymph nodes taken from 26 consecutive patients with GBC who had undergone a radical resection. Histologic sections of the primary tumor and regional lymph nodes in each case were stained with both hematoxylin and eosin and an antibody against cytokeratins 8 and 18 (CAM5.2). A "micrometastasis" was defined as a metastasis missed on routine histologic examination with hematoxylin and eosin but detected by immunohistochemical examination with CAM5.2. Survival rates were calculated only in patients with Stage II or more advanced stage disease. RESULTS: All primary tumors were positive for CAM5.2. Routine histologic examination revealed 53 positive lymph nodes that were stained consistently with CAM5.2. Another seven lymph nodes had micrometastases. Patients with micrometastases showed a significantly worse survival rate than those without micrometastases (P = 0.037, log rank test). Among patients with no lymph node disease on routine histologic examination, there was a trend toward a worse survival rate in those with lymph node micrometastases (P = 0.10, log rank test). The paraaortic lymph nodes were involved more frequently in patients with lymph node micrometastases than those without (P = 0.009, Fisher exact test). CONCLUSIONS: The immunohistochemical detection of lymph node micrometastases using CAM5.2 is feasible in GBC patients and is useful in predicting survival in patients undergoing radical resection. Lymph node micrometastases may be an indicator of widespread lymph node disease in patients with GBC.
Ethnic difference in contribution of Sp1 site variation of COLIA1 gene in genetic predisposition to osteoporosis.
Osteoporosis, a condition characterized by low bone mineral density (BMD) leading to bone fragility [1], is a major public health concern in Japan as well as in other countries. Although genetic predisposition seems to be a factor in the pathogenesis of osteoporosis [2-4], the precise cohort of genes that may be involved is not well defined. The COLIA1 and COLIA2 genes encode polypeptide constituents of collagen type Ialpha1 and Ialpha2, respectively. Both are important candidates as genetic regulators of BMD, since mutations in either gene result in osteogenesis imperfecta, a disorder characterized by severe osteoporosis [5]. Some patients with adult osteoporosis also carry mutations in COLIA1 or COLIA2 genes [6].http://link.springer-ny. com/link/service/journals/00223/bibs/65n5p352.html</++ +hea
Linkage of interleukin 6 locus to human osteopenia by sibling pair analysis.
Osteopenia and osteoporosis are common human conditions considered to result from the interplay of multiple genetic and environmental factors. Twin and family studies have yielded strong correlations between levels of bone mass and a number of genetic factors. The genes involved could regulate metabolism, formation and resorption of bone, all processes that determine bone mass. We tested 192 sibling pairs of adult Japanese women from 136 families for genetic linkage between osteopenia and allelic variants of four candidate genes (interleukin-6, interleukin-6 receptor, calcium-sensing receptor, and matrix gla protein) using qualitative and quantitative methods, and using as genetic markers dinucleotide-repeat polymorphisms present in or near each of those loci. The interleukin-6 locus showed evidence of linkage to osteopenia analyzed as a qualitative trait, with mean allele sharing of 0.40 (P=0.0001) in discordant pairs and 0.55 (P=0.04) in concordant affected pairs. Variation at this locus was also linked to decreased bone mineral density measured as a quantitative trait (P=0.02). Analyses limited only to the post-menopausal women showed similar or even stronger results. No other locus among those tested showed any evidence of linkage by either method. The results provided strong evidence that genetic variation at the interleukin-6 locus affects regulation of bone mineral metabolism and confers risk for osteopenia and osteoporosis in adult women.
Successful resection of metachronous liver metastasis from alpha-fetoprotein-producing gastric cancer: report of a case.
We present herein the case of a 68-year-old man in whom metachronous liver metastasis from an alpha-fetoprotein (AFP)-producing gastric cancer was successfully treated. The patient initially underwent a distal gastrectomy for an AFP-producing gastric cancer on January 30, 1997, following which the serum AFP level which had been 228 ng/ml prior to surgery decreased to 30 ng/ml. However, 7 months after surgery, follow-up examination revealed an abnormal elevation of the serum AFP level up to 301 ng/ml, and a liver tumor was subsequently detected at segment 8 (S8) by abdominal ultra-sonography. There was no evidence of hepatitis B or C virus infections. After various investigations, he was diagnosed to have liver metastases in S6 and S8, from the AFP-producing gastric cancer, and a partial hepatectomy of S6 and S8 was performed. His postoperative course was uneventful and he was discharged on postoperative day 26. Thereafter, his serum AFP levels decreased and have remained within normal limits for 12 months since his operation. To the best of our knowledge, this is the first case of successful resection of metachronous liver metastasis from an AFP-producing gastric cancer.
Remodeling of patellar tendon grafts augmented with woven polyester after anterior cruciate ligament reconstruction in humans.
Arthroscopic and histological evaluations of anterior cruciate ligament (ACL) grafts were made in 38 patients at various intervals after reconstruction was performed with patellar tendons (PTs) augmented with woven polyester. The interval between the surgery and the examinations ranged from 3 to 36 months (mean, 14.1 months). Biopsy specimens with woven polyester were removed from the anterior mid-portion of the graft 5 mm in depth from the graft surface. Arthroscopically, all 38 grafts showed thick ligamentous tissues, but some polyester fibers had ruptured in 9 grafts. The transplanted grafts were arthroscopically very similar to normal ACL 12 months after reconstruction. Histologically, a marked inflammatory response to the woven polyester was observed in the first 4 months after the operation, but this decreased with time. Five of 6 grafts obtained 18-36 months postoperatively showed decreased cellularity, with longitudinally oriented fibrous bundles, suggesting approaching ligament maturity. The appearance of the fibroblasts in the grafts varied from patient to patient, with 13 of 37 grafts (35.1%) showing spindling fibroblasts, and 24 grafts (64.9%) oval ones. (The remaining graft consisted of mesenchynal cells). Clinically, postoperative KT 1000 arthrometer measurements showed that the mean injured-to-uninjured difference in anterior knee laxity was 1.7 +/- 2.6 mm. There was no chronic synovitis or effusion during the study period. These results suggest that grafts with PT augmented with woven polyester transform arthroscopically and histologically into a structure similar to that of normal ligaments after reconstruction, and may act as a substitute for the ACL. The advantage of woven polyester for the augmentation of PT grafts was that it allowed earlier mobilization and weight-bearing after reconstruction, without adverse effects on graft integrity.
Isolation and radiation hybrid mapping of a highly polymorphic CA repeat sequence at the human nuclear factor kappa-beta subunit 1 (NFKB1) locus.
The transcriptional factor nuclear factor kappa-beta (NFKB) consists of a multicomponent protein complex that plays a major role in the regulation of many viral and cellular genes. The NFKB complex has two alternative DNA binding subunits. We isolated a polymorphic dinucleotide (CA) repeat sequence from a genomic clone containing the NFKB subunit 1 (NFKB1) gene located at 4q23-24. High heterozygosity (0.813) makes this polymorphism a useful marker in the genetic study of disorders affecting the immune response and cell differentiation.
High coincidence of Mirizzi syndrome and gallbladder carcinoma.
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Reduced plasma transforming growth factor-beta1 levels in patients with chronic hepatitis C after interferon-alpha therapy: association with regression of hepatic fibrosis.
BACKGROUND/AIM: Transforming growth factor-beta1 is involved in liver fibrosis. Our aim was to examine the association of plasma transforming growth factor-beta1 levels with the degree of liver fibrosis. METHODS: We analyzed plasma transforming growth factor-beta1 levels in 43 patients with chronic hepatitis C treated with interferon-alpha using a transforming growth factor-beta1 ELISA. The content of transforming growth factor-beta1 in liver tissue obtained by needle biopsy (n=13) was also analyzed. The degree of liver fibrosis was assessed histologically and morphometrically. RESULTS: Plasma transforming growth factor-beta1 levels were significantly correlated with transforming growth factor-beta1 content in liver tissue (r=0.83, p<0.001), indicating that plasma levels correspond with tissue cytokine. Plasma transforming growth factor-beta1 levels in patients (8.1+/-1.1 ng/ml) before interferon-a therapy were significantly higher than in controls (1.9+/-0.3 ng/ml) (p<0.01). Plasma levels were significantly correlated with the degree of fibrosis (p<0.01). Plasma transforming growth factor-beta1 levels were significantly decreased in sustained responders (from 5.2+/-1.0 ng/ml to 2.9+/-0.7 ng/ml), relapsed patients (from 9.8+/-2.0 ng/ml to 3.4+/-0.6 ng/ml), and nonresponders (from 9.3+/-2.1 ng/ml to 3.9+/-0.9 ng/ml) at the end of therapy (p<0.05 for all comparisons). Significant regression of liver fibrosis after therapy was observed in both sustained responders and nonresponders (p<0.05 for both). CONCLUSIONS: These observations suggest that plasma transforming growth factor-beta1 levels appear to be associated with the degree of liver fibrosis.
Bacteribilia and cholangitis after percutaneous transhepatic biliary drainage for malignant biliary obstruction.
Cholangitis often develops after percutaneous transhepatic biliary drainage (PTBD) for malignancy. The aims of this retrospective study were to clarify whether or not bacteribilia and cholangitis increase with time after PTBD and to define the pathogenesis of bacteribilia and cholangitis after PTBD. One hundred twenty-eight patients underwent PTBD for malignancy. Both the cumulative incidences of bacteribilia (77%) and cholangitis (28%) showed an increase with time after PTBD. In 78% of patients with bacteribilia, bacteria from intestinal flora were detected in bile. Catheter malfunction (N = 17) or the presence of undrained bile ducts (N = 7) induced cholangitis. Proximal obstruction, because it often accompanied undrained ducts, had higher incidences of bacteribilia (P = 0.04) and cholangitis (P < 0.0001) than did distal obstruction. In conclusion, bacteribilia and cholangitis increase in incidence with time after PTBD. The primary cause of bacteribilia is the transpapillary reflux of intestinal flora. Catheter malfunction or undrained ducts cause cholangitis, provided underlying bacteribilia is present.
Growth of Escherichia coli in propofol, lidocaine, and mixtures of propofol and lidocaine.
BACKGROUND: Microorganisms grow rapidly in propofol. Extrinsic contamination of propofol is thought to be a source of postoperative sepsis and wound infection. We studied growth of a strain of Escherichia coli in thiopental, propofol, lidocaine, and mixtures of propofol and lidocaine. METHODS: The pathogen was exposed to 2.5% thiopental; 1.0% propofol; 1.0%, 2.0% and 4.0% preservative-free lidocaine; and propofol solutions containing 0.25%, 0.5%, 1.0%, 2.0%, or 4.0% lidocaine for 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 h at room temperature, respectively. The inocula from these suspensions were cultured for 48 h at 37 degrees C after the antimicrobial activity of the local anesthetics in the inocula was inactivated by a 1:1000 dilution with distilled water. RESULTS: No organisms grew after exposure to 2.5% thiopental. The exposure of E. coli to propofol increased the colony count to approximately 90 times the control count. The colony counts of E. coli after exposure to 1.0%, 2.0% and 4.0% lidocaine and 0.25%, 0.5%, 1.0%, 2.0% and 4.0% lidocaine in 1.0% propofol were lower than the counts after exposure to 1.0% propofol (P = 0.0048, 0.0027, 0.0003, 0.0503, 0.0188, 0.0080, 0.0044, and 0.0001, respectively). The growth rate of the microorganism was significantly higher in cultures exposed to 1.0% propofol than that in cultures exposed to lidocaine alone or lidocaine-propofol mixtures (P < 0.0001, respectively). CONCLUSION: Lidocaine possesses bacteriostatic activity against E. coli. Addition of lidocaine to propofol confers its bacteriostatic activity to the mixture and may decrease the hazard of infection associated with the extrinsic contamination of propofol.
A highly polymorphic CA repeat marker at the interleukin-11 locus.
The interleukin-11 (IL-11) stimulates T cell-dependent development of immunoglobulin-producing B cells and collaborates with IL-3 in supporting murine megakaryocyte colony formation. The interleukin-11 (IL-11) also stimulates osteoclast formation and inhibits osteoclast function in vitro and has been implicated in estrogen deficiency-induced bone loss. We isolated a polymorphic dinucleotide (CA) repeat sequence from a genomic clone containing the IL-11 gene located at 19q13.3-q13.4. High heterozygosity (0.81) makes this polymorphism a useful marker in genetic study of disorders affecting immune response and bone metabolism.
Cobaltous chloride-induced mutagenesis in the supF tRNA gene of Escherichia coli.
The spectrum of mutations induced by cobalt(II) chloride (CoCl2) was examined using plasmid pUB3 DNA, which was propagated after transfection into Escherichia coli SY1032/pKY241 host cells. The vector plasmid carried an E.coli supF suppressor tRNA gene as a target for mutations. After CoCl2 treatment, 64 independent nalidixic acid-resistant, ampicillin-resistant and Lac+ (SupF-) clones were obtained and the altered sequences of the mutated supF genes were determined. Deletions and frameshifts were the predominant mutational event (61%) induced by CoCl2 and base substitutions were induced to a lesser degree (29%). Analysis of sequence alterations at all the sites of mutation revealed that: (i) 18 of 19 base substitutions and eight of 10 frameshifts occurred at G:C sites, suggesting that the formation of N7G-Co(II) adducts may be responsible for premutagenic lesions of these mutations; (ii) short sequence repeats were mostly found at the sites of deletions and frameshifts. Slippage-misalignment is also suggested to be a mechanism for the induction of mutations at these sites.
Orally administered Panax ginseng extract decreases platelet adhesiveness in 66% hepatectomized rats.
The effect of oral administration of Panax ginseng extract (GE) on platelet adhesiveness was examined in 66% hepatectomized rats. A significant decrease in platelet adhesiveness was obtained when 125 mg/kg/day GE was administered for 6 days before and after hepatectomy. The total cholesterol concentration in the serum was also decreased by GE administration. Food intake was unaffected by GE administration. Serum parameters indicating liver and kidney function were unchanged after GE administration except for lipid metabolic parameters. Because enhanced platelet adhesiveness and hyperlipidemia induces atherosclerosis, these results suggest that orally administered GE is capable of improving the atherosclerotic condition associated with hepatectomy.
Anomalous insertion of the right hepatic duct into the cystic duct: report of a case diagnosed before laparoscopic cholecystectomy.
Although an aberrant hepatic duct entering the cystic duct is not especially rare, the main right hepatic duct entering the cystic duct is extremely rare, with only six cases reported thus far. All of the reported patients underwent open cholecystectomy, during which one patient received a bile duct injury. The anomaly was unsuspected preoperatively in all of these cases. We report an additional patient with this anomaly, the first such case diagnosed before laparoscopic cholecystectomy using direct cholangiography. Cholangiography may be mandatory whenever biliary anomalies are suspected during laparoscopic cholecystectomy. As the right hepatic duct entering the cystic duct can lead to ductal injury, this anomaly should be kept in mind when performing laparoscopic cholecystectomy.