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Biomedical subjects

A Uchida

Publications and source records attributed to A Uchida.

At least 109 records · Page 6Linked to original sources
PubMed1998

Treatment of chronic osteomyelitis using calcium hydroxyapatite ceramic implants impregnated with antibiotic.

We treated eighteen patients with chronic osteomyelitis by implanting pieces of antibiotic-impregnated calcium hydroxyapatite ceramic into a cavity produced after thorough surgical excision of necrotic tissue. Within three months the infected sites had all healed. During follow-up ranging from 24 to 75 months there was no recurrence of infection. Two of the patients had infected prosthetic joints which were successfully revised. Infection was controlled and incorporation of the ceramic material into host bone was demonstrated radiographically. We recommend the use of porous pieces of calcium hydroxyapatite impregnated with antibiotic as a new system for drug delivery in the treatment of chronic osteomyelitis.

Adolescent↗
PubMed1998

Preservation of the knee joint in limb salvage of osteosarcoma in the proximal tibia. A case report.

A 12-year-old boy with osteosarcoma in the proximal tibia underwent a successful limb-saving operation with preservation of the epiphyseal and articular cartilage of the proximal tibia as a result of his remarkable response to chemotherapy. There was no evidence of tumour invasion to the adjacent physis, as demonstrated by image findings. The bone defect was reconstructed using autoclaved autogeneous bone with a vascularized fibula. The patient exhibits excellent function of the affected limb, and the knee joint remains disease-free 55 months postoperatively.

Bone Neoplasms↗
PubMed1998

Effects of kynurenine metabolites on the electrocorticographic activity in the rat.

We examined the effects of kynurenine metabolites administered into the right cerebroventricle (1 micromol) on the electrocorticogram (ECoG) of rats to establish the role of kynurenines on brain function. Kynurenine, anthranilic acid, quinaldic acid, xanthurenic acid or 8-hydroxyquinaldic acid showed no effect on ECoG throughout the recording period of 4 hours. 3-Hydroxykynurenine had a transient suppressive effect on the ECoG, while kynurenic acid caused a slight suppression of ECoG activity. 3-Hydroxyanthranilic acid (3-OH-An), a metabolite of 3-hydroxykynurenine, induced spike discharges with a long latency (60-230 min). 3-OH-An is thought to be metabolized to o-aminophenol, 3-methoxyanthranilic acid, quinolinic acid, 2-ketoadipic acid and picolinic acid. Among 3-OH-An metabolites, only o-aminophenol induced spike discharges several minutes after administration, lasting for 60 min. On the other hand, quinolinic acid suppressed ECoG, though 3-methoxyanthranilic acid, 2-ketoadipic acid and picolinic acid had no effects on ECoG. These electrocorticographic findings suggest that 3-OH-An may induce spike discharges after it is metabolized in the brain to o-aminophenol.

3-Hydroxyanthranilic Acid↗
PubMed1998

Differentiation and apoptosis without DNA fragmentation in cultured Schwann cells derived from wallerian-degenerated nerve.

The Schwann cell cables provide particularly favorable sites for the growth of regenerating axonal sprouts. However, if they remain denervated, endoneurial fibrosis takes place with the Schwann cells atrophying and total Schwann cell number gradually decrease with time. Even when regenerating axonal sprouts invade into the cables, Schwann cells do not survive for long periods if they fail to make axonal contact. These observations strongly suggest the involvement of apoptosis in peripheral nerve degeneration and regeneration. So, we investigated the behavior of Schwann cells prepared from wallerian-degenerated adult rat sciatic nerve in vitro. The secondary cultured Schwann cells showed serial changes in morphology, mitotic activity and migratory activity as they do during Schwann cell cable formation in vivo. At the final stage of differentiation, the Schwann cells became rounded and detached from the flask with extensive blebbing. Electron micrographs clearly demonstrated typical cytoplasmic changes of apoptosis, but, nuclei of most of the cells retained their size and morphology with residual nucleolar structures. An agarose gel electrophoresis of DNA clearly demonstrated that there was not any DNA fragmentation up to 120 h after detachment. Results by in situ apoptosis detection assay did not show any DNA degradation despite the substantial decrease in Schwann cell number. In conclusion, during peripheral nerve degeneration and regeneration, supernumerary Schwann cells are removed by apoptosis, however, it lacks most of the nuclear events of usual apoptosis.

Journal Article↗
PubMed1998

Lower risks of adverse outcome in twins conceived by artificial reproductive techniques compared with spontaneously conceived twins.

The outcomes of twins conceived by 136 women after medical assistance (MA) such as ovulation induction with or without assisted reproductive techniques, and twins conceived spontaneously (SP) by 72 women were compared. All 208 women were monitored from < 20 weeks gestation; they all delivered at > or = 24 weeks gestation. The chorionicity of the placenta was diagnosed antenatally and confirmed after delivery. There were 10 perinatal deaths; the physical and neurological status of the remaining 406 infants was assessed at 1 year of corrected age. There were no differences in gestational age at birth, the birth weights of the larger and smaller twins, the birth weight discordance, or the incidence of life-threatening major malformations between groups. Adverse infant outcomes, such as death, cerebral palsy and mental retardation occurred in nine (3.3%) of 272 MA twins compared with 12 (8.3%) of 144 SP twins (P < 0.05). The placenta was monochorionic in only three (2.2%) of 136 MA twin pregnancies compared with 41 (57%) of 72 SP twin pregnancies (P < 0.001). Of the 21 infants with adverse outcomes, nine had monochorionic placentas. Thus, the risk of an adverse outcome was 2.8-fold higher (95% confidence interval (CI) 1.2-6.4) in monochorionic twins than in dichorionic twins (10 versus 3.7%; P < 0.05). There was no difference in the incidence of adverse infant outcomes between SP (4.8%) and MA (3.4%) twins with dichorionic placentas. These findings suggest that ovulation induction in itself was not associated with an adverse outcome of twin pregnancies. The lower frequency of monochorionic placentas in MA twins may have been responsible for the lower risk of an adverse outcome in MA twins.

Birth Weight↗
PubMed1998

Endoscopic harvesting of radial artery graft for coronary artery bypass.

The radial artery is used frequently in cardiac revascularization and requires an average 23-cm forearm incision. With proper instrumentation (Tsukuba-West Virginia Endoscopic Radial Artery: TW-ERA series, Takumi Cardio Co., Chiba, Japan), the radial artery can be harvested utilizing two small transverse incisions. The authors report six cases of endoscopic harvest of a radial artery graft. Length of the endoscopic incision is 2 cm proximally and 3 cm distally. Operation time and tourniquet times were approximately 80 to 120 minutes. No complications such as hematomas, nerve damage, or delay in healing were observed at the donor sites. Plastic surgeons, with their expertise in radial forearm flaps, hand surgery, and subcutaneous endoscopic techniques, can contribute greatly to the minimally invasive harvesting of the radial artery, preventing associated morbidity and improving the aesthetic and functional outcome of the donor site.

Adult↗
PubMed1998

Blockade of angiotensin II receptors inhibits the increase in blood pressure induced by insulin.

To elucidate whether hyperinsulinemia increases blood pressure by increasing sympathetic outflow via the activation of the central angiotensin system, insulin was infused into urethane-anesthetized rats intravenously (i.v.) or intracerebroventricularly (i.c.v.) under euglycemic conditions. Infusion (i.v.) of insulin elicited pressor effects in a dose-dependent manner (13, 20, and 40 mU/min). Although depressor responses to i.v. injections of hexamethonium were significantly greater in insulin-infused than in saline-infused rats, i.v. captopril and d(CH2)5Tyr(Me)-arginine vasopressin did not show any differences between the groups. Infusions (i.c.v.) of insulin (8 mU/10 microl) also induced cardiovascular acceleration and augmented the depressor response to i.v. hexamethonium in insulin-infused rats. The i.c.v. pretreatment with the angiotensin II antagonist losartan inhibited the pressor responses to both the i.c.v. and i.v. infusion of insulin. These results suggest that the increase in blood pressure induced by euglycemic hyperinsulinemia is elicited by sympathetic activation and that hyperinsulinemia stimulates the angiotensin system in the brain to increase sympathetic nerve activity.

Angiotensin II↗
PubMed1998

Familial occurrence of congenital bile duct cysts.

Congenital bile duct cysts are now a well-documented anomaly of the biliary tree, and have become more common in Japan. Familial occurrence of congenital bile duct cysts, however, is extremely rare, with only six reported cases in the literature. We report a familial pattern of congenital bile duct cysts in a mother and her daughter. A 33-year-old female was admitted for evaluation of right upper quadrant abdominal pain and fever 6 days after an uneventful delivery of her second child. A computed tomography (CT) and ultrasound scan (US) revealed an obstructed biliary tract. Percutaneous transhepatic biliary drainage was then performed, and a cholangiogram revealed a Scholtz type B choledochocele without an anomalous connection of the pancreaticobiliary ducts. Endoscopic US demonstrated that the choledochocele was associated with a stone in the cyst. A pylorus-preserving pancreatoduodenal resection was performed, and a histological study revealed that the choledochocele was lined by biliary mucosa without evidence of malignancy. The newborn infant had an abdominal tumour. An US and CT revealed a congenital bile duct cyst. An operation was performed and the intraoperative cholangiogram showed an Alonso-Lej type I congenital bile duct cyst with an anomalous connection of the pancreaticobiliary ducts. Whether congenital bile duct cysts are hereditary remains to be elucidated.

Adult↗
PubMed1998

Effect of daily vaginal disinfection on duration of gestation after premature rupture of the membranes and on infant outcome.

OBJECTIVES: We examined the effects of daily vaginal disinfection on the interval between premature rupture of the membranes (PROM) and delivery and on infant outcome. METHODS: Daily vaginal disinfection with povidone iodine was performed on 43 women with PROM. The control group consisted of 59 women with PROM who did not undergo vaginal disinfection. In both groups, the infants born to these women were followed until 1 year of corrected age. RESULTS: The degree of cervical dilatation, the leukocyte count, and the serum C-reactive protein level on admission did not differ between the 2 groups. Although there was no difference in the gestational week at delivery between the groups, the interval between PROM and delivery was significantly longer in the disinfectant group than among the control subjects (9.5 +/- 14.9 days vs. 3.9 +/- 5.1 days, p < 0.01). There was no difference in infant outcome between the 2 groups. CONCLUSIONS: These findings suggest that daily vaginal disinfection with povidone iodine prolongs the duration of gestation in women with PROM and dose not have an adverse effect on the fetus.

Adolescent↗
PubMed1998

Acquired thermotolerance and temperature-induced protein accumulation in the extremely thermophilic bacterium Rhodothermus obamensis.

Temperature-induced changes in thermotolerance and protein composition were examined in heat-shocked cells and high-temperature-grown cells of the extremely thermophilic bacterium Rhodothermus obamensis. The survival at temperatures superoptimal for growth (90 and 95 degrees C) was enhanced in both heat-shocked cells and high-temperature-grown cells relative to that of cells grown at optimal temperatures. In a comparison of protein composition using two-dimensional gel electrophoresis, putative heat shock proteins (HSPs) and high-temperature growth-specific proteins (HGPs) were detected. N-terminal amino acid sequence analysis revealed that the putative HSPs were quite similar to the ATP-binding subunits of ABC transporters and the HGPs were proteins corresponding to domains II and III of elongation factor Tu. These results suggested that this extreme thermophile has developed temperature-induced responses that include increased survival under hyperthermal conditions, changes in protein composition, and also the production of novel HSPs.

Amino Acid Sequence↗
PubMed1998

Molecular characterization and postsplicing fate of three introns within the single rRNA operon of the hyperthermophilic archaeon Aeropyrum pernix K1.

The single rRNA operon (arnS-arnL) of the hyperthermophilic archaeon Aeropyrum pernix K1 was sequenced. The DNA sequence data and detailed RNA analyses disclosed an unusual feature: the presence of three introns at hitherto undescribed insertion positions within the rRNA genes. The 699-nucleotide (nt) intron Ialpha was located at position 908 (Escherichia coli numbering [H. F. Noller, Annu. Rev. Biochem. 53:119-162, 1984]) of the 16S rRNA, while the 202-nt intron Ibeta and 575-nt intron Igamma were located at positions 1085 and 1927 (E. coli numbering), respectively, of the 23S rRNA. They were located within highly conserved sites which have been implicated as crucial for rRNA function in E. coli. All three introns were remarkably AT rich (41.5 to 43.1 mol% G+C) compared with the mature rRNAs (67.7 and 69.2 mol% G+C for 16S and 23S rRNAs, respectively). No obvious primary sequence similarities were detected among them. After splicing from rRNA transcripts in vivo, a large quantity of intronic RNAs were stably retained in the linear monomeric form, whereas a trace of topoisomeric RNA molecules also appeared, as characterized by their behavior in two-dimensional gel electrophoresis. Secondary structural models of the Ialpha-, Ibeta-, and Igamma-containing rRNA precursors agree with the bulge-helix-bulge motif. Two of the introns, Ialpha and Igamma, contained open reading frames whose protein translation exhibited no overall similarity with proteins reported so far. However, both share a LAGLI-DADG motif characteristic of homing endonucleases.

Amino Acid Sequence↗
PubMed1998

Cloning, sequence analysis, and expression in Escherichia coli of a gene coding for an enzyme from Bacillus circulans K-1 that degrades guar gum.

A 2,048-bp nucleotide sequence containing a gene coding for an enzyme that degraded guar gum from Bacillus circulans K-1 was identified by polymerase chain reaction walking. This G-gene consisted of 1,551 nucleotides coding for a protein with Mr 55,242. The enzyme was overexpressed in Escherichia coli JM109 cells by the cloning the G-gene downstream of the lac Z promoter of pUC19. The molecular mass of recombinant G-enzyme estimated by SDS-PAGE was 62 KDa, close to that from strain K-1. Analysis of the recombinant enzyme showed GalNAc, Xyl, GlcNAc, Man, Glc, and Gal to account for 1.7%, 14.4%, 6.1%, 3.2%, 54.2%, and 10.4%, respectively, of the total monosaccharides. Polyacrylamide gel electrophoresis of this enzyme with staining gave a red band. The results suggested that the sugars accounted for the differences in the molecular masses. The recombinant enzyme had two kinds of N-terminal sequences, Thr-Met-Ile-Thr-Pro-Ser-Phe-Ala-Ser-Gly-Phe-Tyr-Val-Ile and Ile-Thr-Pro-Ser-Phe-Ala-Ser-Gly-Phe-Tyr-Val-Ile-Gly-Thr. Comparison of these sequences with the deduced N-terminal sequence coded for the G-gene showed that the amino acid, first Met, of the lac Z gene or the next residues Thr-Met in the recombinant enzyme were absent in the native enzyme. Methionines near and at the N-terminus of the mature protein probably were digested by methionine aminopeptidases of E. coli after translation. The properties of recombinant G-enzyme were similar to those of the enzyme from K-1 cells.

Amino Acid Sequence↗
PubMed1998

Induction of human osteoclast-like cells by treatment of blood monocytes with anti-fusion regulatory protein-1/CD98 monoclonal antibodies.

We have developed a new and simple system of human osteoclast formation by fusing peripheral blood monocytes with anti-Fusion Regulatory Protein-1 (anti-FRP-1) monoclonal antibody (mAb). When human blood monocytes were cultured in the presence of anti-FRP-1/CD98 mAbs, polykaryocytes began to appear at approximately 15 h and increased in size with time until 3-4 days of incubation with anti-FRP-1 mAb. These fused cells showed positive staining in tartrate-resistant acid phosphatase, possessed numerous calcitonin receptors, and were capable of bone resorption. These results strongly suggest that anti-FRP-1 antibody-induced multinucleated cells are osteoclasts. Furthermore, FRP-1 antigens were detected in osteoclasts isolated from human bone and in the osteoclast-like cells obtained from human giant cell tumors of bone.

Acid Phosphatase↗
PubMed1997

Smooth muscle cell phenotype-dependent transcriptional regulation of the alpha1 integrin gene.

The expressional regulation of chicken alpha1 integrin in smooth muscle cells was studied. The alpha1 integrin mRNA was expressed developmentally and was distributed dominantly in vascular and visceral smooth muscles in chick embryos. In a primary culture of smooth muscle cells, alpha1 integrin expression was dramatically down-regulated during serum-induced dedifferentiation. Promoter analyses revealed that the 5'-upstream region (-516 to +281) was sufficient for transcriptional activation in differentiated smooth muscle cells but not in dedifferentiated smooth muscle cells or chick embryo fibroblasts. Like other alpha integrin promoters, the promoter region of the alpha1 integrin gene lacks TATA and CCAAT boxes and contains binding sites for AP1 and AP2. The essential difference from other alpha integrin promoters is the presence of a CArG box-like motif. Deletion and site-directed mutation analyses revealed that the CArG box-like motif was an essential cis-element for transcriptional activation in differentiated smooth muscle cells, whereas the binding sites for AP1 and AP2 were not. Using specific antibodies, a nuclear protein factor specifically bound to the CArG box-like motif was identified as serum response factor. These results indicate that alpha1 integrin expression in smooth muscle cells is regulated transcriptionally in a phenotype-dependent manner and that serum response factor binding plays a crucial role in this regulation.

Animals↗
PubMed1997

Neoadjuvant chemotherapy for pediatric osteosarcoma patients.

BACKGROUND: Since the first trial for chemotherapy in children with osteosarcoma in 1977, the survival rate has gradually improved. Currently, more than 60% of all patients are cured, mainly because of the introduction of intensive chemotherapy using doxorubicin, high dose methotrexate, and cisplatin. The increased survival rates have promoted efforts to improve the quality of survival through the use of limb salvage surgery rather than amputation. Improvements in chemotherapeutic efficacy should result in a more favorable outcome and better function of the affected limb. The current study evaluated factors that influence chemotherapy so that a higher survival rate could be obtained. METHODS: Three chemotherapy regimens comprised of doxorubicin, high dose methotrexate, cisplatin, and ifosfamide were retrospectively analyzed in 67 pediatric osteosarcoma patients. Twenty-three patients were treated with chemotherapy comprised of high dose methotrexate and doxorubicin (OOS-A regimen), 25 were treated with OOS-A with the addition of cisplatin (OOS-B), and 19 were treated with OOS-B with the addition of ifosfamide (OOS-C). RESULTS: The OOS-A regimen was poorest in terms of survival (40.6%) compared with the OOS-B (67.5%) and OOS-C regimens (72.5%) (P < 0.001). There was no significant difference in survival between the OOS-B and OOS-C regimens. In the OOS-B regimen, patients who received a higher relative dose intensity showed a better prognosis. CONCLUSIONS: These findings show that doxorubicin, high dose methotrexate, and cisplatin are the most potent drugs and suggest that it is more important to maintain the dose intensity of the regimen to improve survival rather than add a new drug.

Adolescent↗
PubMed1997

Nerve expansion in nerve regeneration: effect of time on induction of ornithine decarboxylase and Schwann cell proliferation.

We studied the effect of initiation time of nerve expansion after nerve transection on the induction of ODC activity and Schwann cell proliferation in nerve tissue under Wallerian degeneration. The levels of ODC activity and Schwann cell proliferation decreased as the initiation time of nerve expansion was delayed after nerve transection, and peak levels of ODC activity following nerve expansion preceded peak levels of Schwann cell proliferation.

Animals↗
PubMed1997

Transient damage to the axonal transport system without Wallerian degeneration by acute nerve compression.

The aim of this study was to examine whether acute nerve compression damages an axonal transport system based on microtubules and how the fibers recover after the compression. A 5-mm segment of the tibial nerve of male wistar rat was compressed with a specially designed clip. Functional recovery was assessed using Tibial Nerve Functional Index (TFI). Rats were sacrificed each day from Day 0 to Day 2 and every 2 days between Day 4 and Day 10. For immunohistochemical analysis of the tibial nerve, the proximal uncompressed, the middle compressed, and the distal uncompressed segments of each section were assessed under immunofluoroscent microscopy for anti-dynein, anti-tubulin, and anti-neurofilament antibodies staining. In rats whose tibial nerve was compressed by 25 g/mm2 of pressure for 5 min, staining of dynein and mirotubules in the compressed portion were obscure on Days 4-8, suggesting that the microtubules based axonal transport system was temporarily damaged, while neurofilaments were retained. In contrast, in the distal portion, anti-neurofilament staining showed no abnormality throughout the experimental period, indicating that Wallerian degeneration did not occur. We conclude that acute nerve compression can cause transient damage to the axonal transport system in nerve fibers without Wallerian degeneration.

Acute Disease↗