Biomedical subjects

A Okada

Publications and source records attributed to A Okada.

At least 91 records · Page 5Linked to original sources

PubMed2000

Difference in human cardiovascular response between upright and supine recovery from upright cycle exercise.

Cardiovascular responses were examined in seven healthy male subjects during 10 min of recovery in the upright or supine position following 5 min of upright cycle exercise at 80% peak oxygen uptake. An initial rapid decrease in heart rate (fc) during the early phase of recovery followed by much slower decrease was observed for both the upright and supine positions. The average fc at the 10th min of recovery was significantly lower (P < 0.05) in the supine position than in the upright position, while they were both significantly greater than the corresponding pre-exercise levels (each P < 0.05). Accordingly, the amplitude of the high frequency (HF) component of R-R interval variability (by spectrum analysis) in both positions was reduced with a decrease in mean R-R interval, the relationship being expressed by a regression line--mean R-R interval = 0.006 x HF amplitude + 0.570 (r = 0.905, n = 28, P < 0.001). These results would suggest that the slower reduction in fc following the initial rapid reduction in both positions is partly attributable to a retardation in the restoration of the activity of the cardiac parasympathetic nervous system. Post-exercise upright stroke volume (SV, by impedance cardiography) decreased gradually to just below the pre-exercise level, whereas post-exercise supine SV increased markedly to a level similar to that at rest before exercise. The resultant cardiac output (Qc) and the total peripheral vascular resistance (TPR) in the upright and supine positions returned gradually to their respective pre-exercise levels in the corresponding positions. At the 10th min of recovery, both average SV and Qc were significantly greater (each P < 0.005) in the supine than in the upright position, while average TPR was significantly lower (P < 0.05) in the supine than in the upright position. In contrast, immediately after exercise, mean blood pressure dropped markedly in both the supine and upright positions, and their levels at the 10th min of recovery were similar. Therefore we concluded that arterial blood pressure is maintained relatively constant through various compensatory mechanisms associated with fc, SV, Qc, and TPR during rest and recovery in different body positions.

Adult↗

PubMed2000

Effect of heat stress on serotonin-2A receptor-mediated intracellular calcium mobilization in rat C6 glioma cells.

This study was conducted to investigate an effect of heat stress at 44 degrees C for 30 min on intracellular Ca2+ signaling system and on heat shock protein (HSP)-70 expression. 5-HT-induced Ca2+ mobilization was reduced 1, 3 and 6 hrs after heat stress, and recovered to the control level 12 and 24 hrs after heat stress. One hr after heat stress, Ca2+ rise was significantly decreased when the cells were stimulated by any concentration of 5-HT. Thrombin-induced Ca2+ increase was also markedly reduced 1 hr after heat stress. HSP-70 level was increased 6 and 9 hr after heat stress. In HSP synthesis inhibitor quercetin-treated cells, HSP-70 expression was not enhanced after heat stress, and Ca2+ rise in response to 5-HT did not return to the control level. However, the Ca2+ rise induced by 5-HT was not restored to the control level after stress in Ac-Asp-Glu-Val-Asp-H (DEVD)-exposed cells while DEVD had little effect on heat stress-induced synthesis of HSP-70. Dexamethasone did not alter the change in HSP-70 expression or Ca2+ response after heat stress. These results indicate that heat stress attenuated 5-HT-induced Ca2+ mobilization and that HSP-70 expression played an important role in recovery from Ca2+ impairment, possibly via protease activity in C6 cells.

Animals↗

PubMed2000

Determination of imbalance between MMP-2 and TIMP-2 in human neuroblastoma by reverse-transcription polymerase chain reaction and its correlation with tumor progression.

BACKGROUND/PURPOSE: The matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs) have been implicated in tumor invasion and metastasis. Net matrix degradation and proteolysis depend on the critical local balance between MMPs/TIMP-2. We attempted to determine their expression balance and to evaluate its importance with tumor progression. METHODS: Expressions of MMP-2, MMP-9, and TIM P-2 mRNAs was quantified by reverse-transcription polymerase chain reaction (RT-PCR) in tumor tissues from 25 neuroblastoma patients. RESULTS: MMP-2, MMP-9, and TIMP-2 expression was observed in all the samples but with different trends. Increased expressions of MMP-2 mRNA was evident in advanced stages (Evans' stage III and IV; P = .02; unpaired ttest), and in patients who died of progressive disease (P = .0001). Whereas, the expressions of MMP-9 and TIMP-2 had no such significant association with clinical stages and prognosis. The ratio of MMP-2/TIMP-2 mRNAs was significantly higher in the advanced stages versus early stages (mean +/- SD = 1.66+/-0.65 and 1.11+/-0.34, respectively; P = .02) and in patients who died of progressive disease versus alive patients (mean = 2.13+/-0.78 and 1.21+/-0.36, respectively; P = .0006). CONCLUSIONS: Coexpression of MMPs and TIMP-2 in neuroblastoma indicates the need to evaluate their expression balance. Significantly higher expression of MMP-2 mRNA and increased ratio of MMP-2 and TIMP-2 mRNAs in advanced stages or patients who have died of progressive disease suggests an association between elevated MMP-2 expression and poor prognosis. To establish the role of enzyme to inhibitor mRNA ratio as a reliable predictor, cohort studies with significant number of cases may be carried out.

Base Sequence↗

PubMed2000

Pexis of the great vessels for patients with tracheobronchomalacia in infancy.

BACKGROUND/PURPOSE: Aortopexy has been established as a surgical treatment for tracheobronchomalacia in infancy. However, the effects in patients with bronchial involvement remain controversial. The authors performed aortopexy and pexis of the pulmonary artery trunk (PApexy) for patients with tracheobronchomalacia. METHODS: Between 1992 and 1997, 14 infants with tracheobronchomalacia were treated. Patients ranged in age from 4 months to 7 years (median, 3.5 years). Using patients' records, intraoperative bronchofiberscopic results and clinical outcomes were analyzed retrospectively. RESULTS: Concerning tracheomalacia, aortopexy eliminated airway collapse as shown by intraoperative fiberscopic results and clinical outcome in 4 patients. Regarding tracheobronchomalacia, aortopexy eliminated collapse of the trachea and the right main bronchus in 3 patients but did not improve collapse of the lower half of the left main bronchus in 3 patients, which was eliminated by PApexy. Aortopexy eliminated airway collapse of the left main bronchus in 1 of 3 patients with bronchomalacia. PApexy eliminated collapse of the lower half of the left main bronchus in 1 patient. CONCLUSIONS: These results indicate that intraoperative bronchofiberscopic results were closely correlated to the clinical outcome, and suggest that aortopexy is helpful for eliminating collapse of the right main bronchus and the proximal half of the left main bronchus and that PApexy eliminates collapse of the distal half of the left main bronchus.

Abnormalities, Multiple↗

PubMed2000

The third zinc finger of TFIIIA stabilizes a hairpin structure of the non-coding strand in the internal control region of 5S RNA gene.

The structures of non-coding and coding strands in box C of the internal control region (ICR) of Xenopus laevis somatic 5S RNA gene have been examined by circular dichroism (CD) and Raman spectroscopy in the absence and presence of the third zinc finger of transcription factor IIIA (TFIIIA), which binds to the ICR. The non-coding strand exhibits CD signals assignable to a hairpin and an unfolded structure. The presence of the hairpin structure is supported by Raman spectra, gel electrophoresis, and nucleotide deletion experiments. Binding of the zinc finger to the non-coding strand increases the CD signal of hairpin structure, indicating stabilization of the hairpin structure by the zinc finger. In contrast, the corresponding coding strand remains unfolded even in the presence of the zinc finger. The TFIIIA-ICR complex is not only required for initiation of transcription but also lasts during many rounds of transcription of the 5S RNA gene including the ICR (Bogenhagen et al., Cell 28 (1982) 413). TFIIIA may play a role in promoting the transcription by maintaining the unwound non-coding strand in the hairpin structure and leaving the coding strand available for transcription by RNA polymerase.

Animals↗

PubMed2000

Lithium chloride inhibits thrombin-induced intracellular calcium mobilization in C6 rat glioma cells.

In this study, the authors have demonstrated the effect of lithium, a typical mood stabilizer, on thrombin-evoked Ca2+ mobilization in C6 cells to elucidate the action mechanisms of the drug. Thrombin-induced Ca2 mobilization was reduced 24 hr after 1 or 10 mM lithium chloride (LiCl) pretreatment. The Ca2+ rise was reduced in a time-dependent manner, and the significant inhibition was observed 9 hr pretreatment with 10 mM LiCl. On the other hand, pretreatment of the cells with 10 mM LiCl for 24 hr did not alter the amount of Galphaq/11 significantly. Pretreatment with 10 mM LiCl for 24 hr failed to reduce the 5-HT-induced Ca2+ mobilization or to affect the desensitization of the 5-HT signal. Finally, thrombin-elicited Ca2+ rise was markedly inhibited in the presence of 0.05 U/ml plasmin, however, the Ca2+ rise was not further attenuated in the presence of plasmin in C6 cells pretreated with LiCl for 24 hr. These results indicate that pretreatment with LiCl attenuated thrombin-evoked intracellular Ca2+ mobilization in plasmin sensitive manner in C6 rat glioma cells. Thus, it is important to investigate the effect of lithium on thrombin-induced cellular responses to clarify the action mechanism of lithium in relation to some abnormality in thrombin-evoked Ca2+ rise observed in bipolar disorders.

Animals↗

PubMed2000

Nitric oxide synthase inhibitor attenuates inflammatory lesions in the skin of zinc-deficient rats.

Skin lesions are common manifestations of zinc deficiency in humans and animals, but the pathogenic mechanisms have not been fully clarified. In the present study, a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), was given to zinc-deficient (ZD) rats to see whether it prevents or delays the occurrence of skin lesions. Weanling male rats were given free access to a ZD diet (2 mg zinc/kg) for 4 wk to induce zinc deficiency. Control rats, including pair-fed (PF) and ad libitum (AL) groups, were given a diet supplemented with zinc (50.8 mg zinc/kg. L-NAME (0.3 g/L in drinking water) was given to some ZD rats for 3 wk, starting at the second week of their ZD dieting. Dermatitis of the extremities, balanitis, stomatitis, and alopecia appeared in ZD but not in AL and PF rats. Administration of L-NAME significantly reduced the frequency of cutaneous and mucocutaneous inflammatory lesions but did not prevent alopecia in the ZD rats. Reverse transcription polymerase chain reaction showed that inducible nitric oxide synthase mRNA was expressed in the paw skin of ZD but not of AL and PF rats. Evaluation of skin microvascular permeability by the Evans blue leakage technique indicated that L-NAME administration significantly attenuated extravasation of Evans blue in the paw skin of ZD rats. Furthermore, stains positive for terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling were condensed and diffusely distributed over the epidermis, dermis, and subcutaneous tissue of paws in ZD rats. ZD rats had intense cell infiltration and parakeratosis in the paw skin. L-NAME administration effectively prevented these morphologic changes. These results demonstrate that nitric oxide synthase inhibitor ameliorates inflammatory lesions of the skin in ZD rats.

Animals↗

PubMed2000

Identification of cis-acting promoter elements that support expression of membrane-type 1 matrix metalloproteinase (MT1-MMP) in v-src transformed Madin-Darby canine kidney cells.

Membrane-type 1 matrix metalloproteinase (MT1-MMP) expressed in tumor cells is believed to be important for the pericellular degradation of extracellular matrices during invasion and metastasis. To analyze the mechanism by which MT1-MMP becomes expressed in cancer cells, we assessed the MT1-MMP promoter region for the presence of cis-acting promoter elements that support transcription in transformed cells. Our tumor model consisted of Madin-Darby canine kidney (MDCK) cells transformed by v-src (src4 cells). MT1-MMP mRNA was only faintly detected in parental cells but was strongly expressed in the src4 cells. In parallel, src4 cells invaded into collagen gels, whereas MDCK cells did not. When MDCK and src4 cells were transiently transfected with a plasmid containing of -3000 to -99 nt from the upstream region of the MT1-MMP gene, the promoter activity was 2.6-fold higher in src4 cells than in MDCK cells. Furthermore, the region between -399 and -356 nt was found to contain the src4-specific enhancer element(s). Tandem Sp1 binding sites were also found to be essential in promoting transcription. An Egr-1 site that partially overlaps with the Sp1 sites was found to cooperate with the src4-specific enhancer and to also contribute weakly to the basal promoter activity. The presence of transcription factors that bind to the src4-specific enhancer site was detected by mobility-shift assays in src4 cell nuclear extracts but only weakly in MDCK extracts. Thus, we have identified a novel enhancer element that acts specifically in the transformed cells to enhance MT1-MMP expression.

Animals↗

PubMed2000

Congenital urethrocutaneous fistula.

BACKGROUND: A 3-year-old boy visited our hospital for aberrance of urination. He had a fistula on his ventral penile shaft. Our diagnosis was congenital urethrocutaneous fistula. METHODS/RESULTS: We performed one-stage repair transverse preputial onlay island flap urethroplasty. Postoperatively, the patient was voiding comfortably with no recurrence of fistula. CONCLUSIONS: Congenital urethrocutaneous fistula is rare. Eighteen cases of congenital urethrocutaneous fistula have been reported previously. We consider the etiology of congenital urethrocutaneous fistula as a deficiency of the urethral plate and fusion of urethral folds.

Child, Preschool↗

PubMed2000

Patent ductus venosus with a hypoplastic intrahepatic portal system presenting intrapulmonary shunt: a case treated with banding of the ductus venosus.

A case of patent ductus venosus (PDV) presenting intrapulmonary shunting is described. Although retrograde venography of ductus venosus showed few intrahepatic branches, banding of PDV resulted in increased intrahepatic portal branches and disappearance of symptoms 10 months after the operation. Banding of the ductus venosus may be effective in PDV even with hypoplastic intrahepatic portal system.

Child↗

PubMed2000

Airway anomalies in patients with congenital diaphragmatic hernia.

PURPOSE: Congenital diaphragmatic hernias (CDH) sometimes are associated with airway anomalies such as congenital stenosis, abnormal branching of the bronchi, and pulmonary hypoplasia. The incidence of these associated airway anomalies has not been reported previously. METHODS: Bronchoscopy was performed in all neonates with CDH from 1987 to 1999. In addition to anatomic anomalies, bronchial hypoplasia was defined as narrowing and shortening of the bronchi at bronchoscopy. RESULTS: Anatomic anomalies were identified in 7 of 39 patients with CDH: 1 had congenital tracheal stenosis with pulmonary artery sling, 1 had a defect of the right upper lobe bronchus, 2 had a tracheal bronchus, and 3 had a trifurcated trachea. Bronchial hypoplasia on the affected side was identified in 15 patients and was seen in all patients with anatomic anomalies of the tracheobronchial tree except the 2 with tracheal bronchus. After excluding 5 patients with severe associated anomalies, 6 of 14 patients with an abnormal tracheobronchial tree died, whereas 1 of 20 patients without airway abnormalities died. CONCLUSIONS: Anatomic anomalies of the tracheobronchial tree and bronchial hypoplasia on the affected side were identified in 17.9% and 38.4% of patients with CDH, respectively. CDH patients who exhibited these abnormalities showed a poor outcome.

Bronchial Diseases↗

PubMed2000

Transjugular intrahepatic portosystemic shunt performed in a 2-year-old infant with uncontrollable intestinal bleeding.

Although transjugular intrahepatic portosystemic shunt (TIPS) is widely accepted in adults, there have been few successful reports in infants. The authors describe a 2-year-old boy with postoperative biliary atresia who underwent TIPS for uncontrollable lower intestinal bleeding and achieved hemostasis. Massive melena developed, which was not controlled by conservative therapy and devascularization. A shunt was created between the right hepatic vein and the right portal vein with a 6- x 50-mm Wallstent. After TIPS, the porto-systemic pressure gradient decreased from 15 to 11 mm Hg, and collaterals markedly reduced. He has not had recurrent bleeding for over 7 months. TIPS may be a technically feasible and effective treatment to control intestinal bleeding in infants. However, further experience and long-term follow-up will be required.

Biliary Atresia↗

PubMed2000

Measurement of serum hyaluronic acid as a sensitive marker of liver fibrosis in biliary atresia.

PURPOSE: The aim of this study was to clarify whether serum hyaluronic acid level (SHA) can reflect the degree of liver fibrosis in biliary atresia (BA). METHODS: SHA was measured in 44 postoperative BA patients at 7 months to 22 years of age, with sandwich enzyme method (Hy-A 100 kit). SHA was compared with T.Bil (group 1, T Bil < 2; group 2, 2 < or = T Bil < 5; group 3, T Bil > or = 5 mg/dL), fibrosis score (0-6, the number of abnormal values among Alb, PT, ChE, T Chol, Fischer's ratio, prealbumin), and histologic grading (0-IV). RESULTS: SHA was 499.8 +/- 332.5 in group 3, significantly higher than in the control, group 1, or group 2. As fibrosis score rose, SHA became higher, and SHA in Score 6 (430.1 +/- 366.1 ng/mL) and score-5 (172.9 +/- 141.8 ng/mL) was significantly higher than in the control and other scores, respectively. As the histologic grade rose, SHA became higher, and SHA in grade IV (444.8 +/- 323.5 ng/mL) and grade III (166.0 +/- 70.3 ng/mL) was significantly higher than in the control or other Grades. Serial change of SHA since before HPE was parallel to the clinical course in 8 patients. CONCLUSION: SHA may be a useful serum marker reflecting the degree of liver fibrosis in BA.

Adolescent↗

PubMed2000

Development of intrapulmonary arteriovenous shunting in postoperative biliary atresia: evaluation by contrast-enhanced echocardiography.

PURPOSE: This report presents biliary atresia (BA) patients with intrapulmonary arteriovenous shunting (IPS), which was evaluated suitably by contrast-enhanced echocardiography (CEC). METHODS: Of 88 BA patients seen in the last 20 years, 8 (9.1%) had IPS at 8 months to 16 years of age. Two were associated with polysplenia syndrome, 1 had persistent jaundice after hepatic portoenterostomy, and 2 underwent splenorenal shunt. According to the comparison between microbubbles in left atrium (LA) and in right atrium (RA) detected by CEC, IPS was classified as grade I, mild (LA << RA); grade II, moderate (LA < RA); grade II, severe (LA = RA). RESULTS: Grade I consisted of 4 patients whereas grade II and III held 2 patients each. Clinical symptoms such as cyanosis, exertional dyspnea, or clubbing were present in 50% of grade I and all of grade II and IlI. Mean PaO2 in grade I, II, and III was 70.5, 50.4, and 35.3 mm Hg, respectively. In 1 patient with grade I, IPS spontaneously disappeared, but pulmonary hypertension developed later. One patient in grade II died of pulmonary complications, and the other is considered a candidate for livertransplantation (LTx). One patient in grade III died of liver failure, whereas the other is free of IPS after LTx. CONCLUSION: IPS can lead to a life-threatening complication in postoperative BA patients, and CEC may be a convenient and useful method to evaluate the degree of IPS and determine therapeutic strategy.

Adolescent↗

PubMed2000

Motor function of the esophagus and the lower esophageal sphincter in children who undergo laparoscopic nissen fundoplication.

BACKGROUND/PURPOSE: To define the clinical role of laparoscopic Nissen fundoplication (LNF) in children with gastroesophageal reflux (GER), an appropriate understanding of its functional effects is required. The aim of this study was to investigate the motor function of the esophageal body and the lower esophageal sphincter (LES) with special reference to the effects of caloric nutrients in children undergoing LNF. METHODS: Studies were performed in 12 children with GER (age, 6 months to 13 years) before and a month after LNF. Continuous manometric examination was performed with an infusion system using a sleeve sensor for an hour each before and after the administration of apple juice (AAJ; 10 mL/kg). RESULTS: AAJ increased postoperative basal LES pressure from 15 +/- 7 to 20 +/- 6 mm Hg, whereas it decreased the preoperative values from 13 +/- 5 to 10 +/- 4 mm Hg (P < .05). Significant residual pressure was noted at the nadir of swallow-induced LES relaxation after LNF, which was increased by AAJ from 7 +/- 3 to 11 +/- 4 mm Hg. A child with a high nadir LES pressure showed postoperative dysphagia. Significant changes in the patterns of esophageal contractions were not noted after LNF. CONCLUSIONS: Characteristics of the effect of LNF on the LES were a postprandial increase of basal LES pressure and significant residual LES pressure at the nadir of LES relaxation. The motor function of the esophageal body was not affected by LNF.

Adolescent↗

PubMed2000

Total parenteral nutrition-associated intrahepatic cholestasis in infants: 25 years' experience.

BACKGROUND/PURPOSE: There are few long-term chronological reviews examining the incidence of total parenteral nutrition (TPN)-associated intrahepatic cholestasis (TPNAC) in infants. The authors therefore reviewed TPNAC in their 25-year series, and also looked at the current problems associated with TPN in infants. METHODS: Two hundred seventy-three surgical neonates who received TPN for more than 2 weeks were divided into 3 groups chronologically: group A (1971 through 1982, n = 77), group B (1983 through 1987, n = 72), and group C (1992 through 1996, n = 124). TPNAC was defined as serum direct bilirubin (DB) level greater than 2.0 mg/dL during the neonatal period. RESULTS: The incidence of TPNAC in groups A, B and C was 57%, 31%, and 25% (P< .01), respectively, and the mortality rate from TPN-associated complications was 13%, 3%, and 3% (P< .05), respectively. Over the last 5 years, severe TPNAC developed in 20 patients (16%). Four of 20 died of TPN-associated sepsis with hepatic failure; 2 had hypoganglionosis with intractable stagnant enteritis and subsequent sepsis, and 2 had fatal respiratory or cardiac disease. CONCLUSIONS: The incidence of TPNAC in surgical neonates and TPN-associated mortality rates have decreased significantly. The mortality rate, however, still remains at 3%. Two of 4 fatal cases had hypoganglionosis, which were totally dependent on TPN. In patients who require long-term TPN, TPN still has unsolved problems, and small bowel transplantation may be indicated.

Cholestasis, Intrahepatic↗

PubMed2000

Diagnostic significance of pancreas divisum in early life.

Pancreas divisum (PD) is a congenital anomaly in which the ventral and dorsal pancreatic ducts fails to fuse in the early fetal period. This anomaly has been known to rarely cause recurrent pancreatitis and to require surgical intervention. With the recent advances in image diagnostic procedures, an increasing incidence of this anomaly has been recognized in the pediatric age group. Seven cases of PD were encountered in our institution between 1978 and 1998. Six were female and one was male, with a mean age of 8 years. All cases were diagnosed to have PD by endoscopic retrograde pancreatography (ERCP) or operative pancreatography. One case (14.3%) had PD associated with a bout of pancreatitis and was operated on by transduodenal papilloplasty, but recurrent bouts of pancreatitis led to the performance of longitudinal pancreaticojejunostomy (Puestow procedure). Six cases (85.7%) were found to have PD as an incidental finding during operation for congenital dilatation of the bile ducts (CDBD), however, 2 cases (33.3%) out of the 6 developed pancreatitis in a later stage and ERCP was effective in their follow-up assessment. One benefited from conservative treatment while the other needed transduodenal papilloplasty along with pancreatoductoplasty. Imaging procedures (ERCP or operative pancreatography) revealed complete PD in 3 cases (42.9%), and incomplete PD in 4 cases (57.1%), however, there was no clinically significant difference between the groups.

Bile Ducts↗

PubMed2000

Effective percutaneous transhepatic biliary drainage for cystic dilatation of the intrahepatic biliary system in biliary atresia: a case report.

We report on a 16-year old girl with postoperative biliary atresia developing cystic dilatation of the intrahepatic biliary system (CDIB) with abdominal pain, which was relieved after percutaneous transhepatic biliary drainage (PTBD). A cyst was detected in segment 4 of the liver at the age of 14 years. She developed severe right hypochondralgia, subfever and liver dysfunction. Percutaneous cholangiogram showed a solitary cyst without communication and a PTBD tube was placed within the cyst. After lavage of the cyst through PTBD, CDIB was re-communicated with the intestine and the pain was relieved with reduction of the cyst size. From this experience, PTBD may be a less invasive treatment as the first choice for non-communicating CDIB and may alleviate the symptoms when recommunication with the intestine is obtained.

Adolescent↗