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Biomedical subjects

Yukihiro Takahashi

Publications and source records attributed to Yukihiro Takahashi.

At least 19 recordsLinked to original sources
PubMed2006

Effectiveness of carvedilol for congestive heart failure that developed long after modified Fontan operation.

We report a case of a patient with severe heart failure after Fontan procedure in whom carvedilol was very effective. A 27-year-old man had intractable congestive heart failure due to severe ventricular dysfunction after Fontan operation. Central venous pressure was elevated to 29 mmHg. A right-to-left shunt was noted across a large collateral vessel between the innominate vein and the pulmonary vein. He was administered carvedilol (initial dose, 2 mg/day; maximum dose, 30 mg/day). Cardiac catheterization performed 1 year after carvedilol administration revealed a decrease in atrial pressure and improvement of ventricular function. He underwent a conversion operation to total cavopulmonary connection (TCPC) and ligation of a collateral vein communicating with the innominate and pulmonary veins. Carvedilol may be a legitimate treatment before TCPC conversion or heart transplantation for the high-risk group of patients with a failed Fontan circulation.

Adrenergic beta-Antagonists↗
PubMed2006

Arterial switch operation using aortic homograft for transposition of the great arteries with pulmonary regurgitation.

We report a case of a 15 month-old boy who underwent the arterial switch operation using cryopreserved aortic homograft for transposition of the great arteries with pulmonary regurgitation, with coexisting right ventricular outflow tract obstruction precluding atrial switch operation. Follow-up echocardiography at 6 months showed trivial neoaortic valve regurgitation, no significant systemic outflow obstruction, with good cardiac function. In small children, the choice of material for left ventricular outflow tract reconstruction is one of the most crucial issues. Cryopreserved homograft has been one of the primary options for the aortic valve replacement in small children because of the ease of suturing and excellent hemostasis.

Aorta↗
PubMed2006

End-to-side anastomosis for coarctation of the aorta and type A aortic arch interruption with hypoplastic aortic arch.

OBJECTIVE: We investigated the advantages of reconstructing the aortic arch in neonates and infants by end-to-side anastomosis (ESA) in aortic coarctation and type A aortic arch interruption. SUBJECTS AND METHODS: The patients were 28 neonates and infants who underwent median full sternotomy for correction of aortic coarctation (CoA) and type A interrupted aortic arch (IAA), at our institute, from October 1997 to September 2002. The cases were divided into two groups: ESA was performed in 16 cases (group A) and extended end to end anastomosis in 12 cases (group B). All repairs were made using simple clamping of the descending aorta under cardiac arrest. We compared groups A and B with regard to duration of simple clamping, postoperative blood pressure in the upper and lower extremities, echocardiographic pressure gradient, and the presence or absence of tracheal stenosis as diagnosed by postoperative clinical symptoms and chest radiography. RESULTS: No significant difference between the groups was found in age, gender, body weight, or the ratio of CoA to IAA. In addition, there was no difference between the two groups in the duration of simple clamping or the difference in blood pressure between the lower and upper extremities. However, the echocardiographic pressure gradient at the site of anastomosis in group A was significantly lower than that in group B. There were no cases with symptoms of bronchial stenosis in either group. CONCLUSION: ESA is a relatively simple method for treating CoA or IAA with hypoplastic aortic arch, and was found to be effective for the elimination of residual stenosis.

Anastomosis, Surgical↗
PubMed2006

Juvenile-onset hypergammaglobulinemic purpura and fetal congenital heart block.

Waldenström's hypergammaglobulinemic purpura (HGP) is a rare chronic disorder characterized by recurrent purpura on the legs, a polyclonal increase in serum gamma-globulin, an elevated erythrocyte sedimentation rate and a positive rheumatoid factor. A 30-year-old primigravid woman with 14 years of HGP was found to have fetal bradycardia at 25 weeks' gestation. Laboratory investigations demonstrated positive anti-Ro/SSA and anti-La/SSB antibodies in the maternal serum. Cesarean delivery was performed at 39 weeks, and a 2750-g female infant was born with complete atrioventricular block. Fortunately, the neonatal period has been uneventful without need for pace-making. Maternal HGP exacerbated just after delivery, but resolved within 1 week without treatment. Physicians should be aware of the possible presence of neonatal lupus-related anti-Ro/SSA and anti-La/SSB autoantibodies in patients with HGP. Screening for these autoantibodies is important and could be used as a marker to identify and manage high-risk pregnancies.

Adult↗
PubMed2006

Suppressive effect of alpha2 Heremans-Schmid glycoprotein on in vitro calcification of osteogenesis.

BACKGROUND: alpha(2) Heremans-Schmid glycoprotein (alpha(2)HS glycoprotein) is predominantly found in bone. To date, we have investigated plasma alpha(2)HS levels in immature babies and neonates as well as the histological distribution in various neonatal tissues in order to clarify its physiological significance. In an effort to understand the physiological function of alpha(2)HS glycoprotein in bones, we studied the effects of alpha(2)HS glycoprotein in cultured osteogenesis model using rat marrow cells. METHODS: We added different concentrations of alpha(2)HS glycoprotein to cultured marrow cells, including osteoblasts in the presence of dexamethasone, in an attempt to elucidate the effects of alpha(2)HS glycoprotein on osteoblast growth and bone calcification in vitro. RESULTS: The results showed that total DNA content was significantly increased with 0.2-20 nM (f.c.) alpha(2)HS glycoprotein, but was neither suppressed nor increased with 200 nM (f.c.) alpha(2)HS glycoprotein. Although ALP activity increased with 0.2 or 2 nM (f.c.) alpha(2)HS glycoprotein, it decreased with 20 or 200 nM (f.c.) alpha(2)HS glycoprotein. While 0.2 nM (f.c.) alpha(2)HS glycoprotein had no effect on calcium or osteocalcin content, 2 nM (f.c.) alpha(2)HS glycoprotein decreased both calcium content and osteocalcin content by about half, and no calcium or osteocalcin was observed with 20 or 200 nM (f.c.). Calcium staining of cultured marrow cells revealed that the number of stained cell tubercles decreased in a concentration-dependent manner. CONCLUSION: These findings suggest that alpha(2)HS glycoprotein regulates the growth of osteoblasts and acts as an inhibitory factor in the regulation of bone calcification.

Animals↗
PubMed2006

Contribution of sialic acid-binding adhesin to pathogenesis of experimental endocarditis caused by Streptococcus gordonii DL1.

An insertional mutation in hsa, the gene encoding the sialic acid-binding adhesin of Streptococcus gordonii DL1, resulted in a significant reduction of the infection rate of the organism and an inflammatory reaction in the rat aortic valve with experimental endocarditis, suggesting that the adhesin contributes to the infectivity of the organism for heart valves.

Adhesins, Bacterial↗
PubMed2006

Consensus guideline for diagnosis and treatment of childhood idiopathic thrombocytopenic purpura.

A practice guideline aimed at standardizing the treatment for childhood idiopathic thrombocytopenic purpura (ITP) is presented. This consensus guideline is based on a survey carried out via a questionnaire prepared by the ITP Committee of the Japanese Society of Pediatric Hematology and sent to society members. The survey questionnaire included questions on the diagnosis of ITP submitted for the purpose of revising the ITP diagnostic guideline prepared in 1990 by the Research Group for Intractable Hematopoietic Disorders; a revised diagnostic guideline also is presented.

Diagnosis, Differential↗
PubMed2005

Ross procedure in an infant weighing 4.5 kg: eight years follow-up.

A 6 month-old male infant (weight: 4.5 kg) with congenital aortic stenosis underwent aortic valve replacement with a pulmonary autograft (Ross procedure). The right ventricular outflow tract (RVOT) was reconstructed with a polytetrafluoroethylene (PTFE) -valved equine pericardial conduit. At the age of 5, re-RVOT reconstruction with an equine pericardial patch bearing a PTFE monocusp was required because of severe pulmonary stenosis resistant to 2 attempts of percutaneous transluminal pulmonary valvotomy. Currently, at the age of 8, the degree of aortic regurgitation is trivial and the pulmonary autograft is free of functional deterioration despite somatic growth.

Aortic Valve Stenosis↗
PubMed2005

Mitral valve replacement in children under 3 years of age.

OBJECTIVE: This study was undertaken to review our experience of mitral valve replacement in children under 3 years of age. METHODS: Between January 1990 and May 2004, 18 patients under 3 years of age underwent a total of 20 mitral valve replacements using a bileaflet mechanical prosthetic valve. There were 9 males and 11 females. The age at surgery ranged from 3 months to 3 (mean=1.02 +/- 0.72) years and body weight varied between 3.4 and 13.2 (mean=7.08 +/- 2.74) kg. RESULTS: There were 4 early and 2 late deaths, and these occurred in severe cases aged less than 1 year of age. Re-replacement of mitral valve was required in 3 patients (valve thrombosis in 2 and pannus formation in 1). Orifice size of the implanted prosthesis (OS) as compared with the predicted normal size of the mitral valve (NS) was well correlated with maximum transprosthetic flow velocity estimated by Doppler echocardiography. In this study, the OS/NS>0.65 was maintained in all patients, and none required re-replacement because of prosthesis-patient mismatch. CONCLUSION: Patients less than 1 year of age had significant mortality and morbidity. The results were satisfactory in the remainder (1-3 years). During this follow-up period, none required re-replacement due to somatic growth, but it will be an unavoidable problem in the future. The OS/NS, which can be checked with a regular physical examination, may serve as a guide to determine the most appropriate timing for the second surgery.

Child, Preschool↗
PubMed2005

Short operation time: an important element to reduce operative invasiveness in pediatric cardiac surgery.

BACKGROUND: The mini skin incision procedure is considered an important element of minimally invasive cardiac surgery because of its definitive cosmetic advantage. However, the operative hazard of limited exposure may be associated with prolonged operation time and increased surgical insult. METHODS: A total of 357 consecutive patients undergoing repair of an isolated atrial or ventricular septal defect, in whom the mini skin procedure was applied, were investigated. Patients were grouped by diagnosis and body weight. Univariate and multivariate risk analyses were conducted in the specific patient group undergoing ventricular septal defect repair weighing less than 5 kg. RESULTS: The operation time was reduced by 21.0% (93.4 to 73.8 minutes) during this time period. Univariate risk analysis revealed that the operation time had a significant correlation with time to extubation (p < 0.0001), catecholamine duration (p = 0.0003), intensive care unit stay (p < 0.0001), hospital stay (p = 0.016), arterio-alveolar oxygen tension difference at the time of extubation (p = 0.0253), and furosemide dose required in the first 24 hours (p = 0.0332). Multiple linear regression analysis revealed that the operation time had an impact on time to extubation, arterio-alveolar oxygen tension difference at the time of extubation, and intensive care unit stay. The length of skin incision was not correlated with any outcome measure. CONCLUSIONS: The mini skin incision, if associated with prolonged operation time, may increase the overall insult in pediatric cardiac surgery. In order to reduce operative invasiveness, simultaneous effort to reduce, or at least not to increase, the operation time are mandatory.

Cardiac Surgical Procedures↗
PubMed2005

Steroid supplementation: a legitimate pharmacotherapy after neonatal open heart surgery.

BACKGROUND: An inflammatory response together with multiple organ failure subsequent to cardiopulmonary bypass is especially prominent in neonates. The behavior of glucocorticoids during this period in these patients is not known. If adrenal insufficiency should exist, it could considerably compromise postoperative recovery. METHODS: Twenty neonates undergoing biventricular repair were enrolled. Ten patients were assigned to receive hydrocortisone treatment and the other 10 to receive placebo. The treatment group received stress-dose hydrocortisone sodium succinate after discontinuation of cardiopulmonary bypass: 0.18 mg.kg(-1).hr(-1) for 3 days, 0.09 mg.kg(-1).hr(-1) for 2 days, and 0.045 mg.kg(-1).hr(-1) for 2 days. The placebo was 5% glucose solution. RESULTS: Patients had adrenal insufficiency (cortisol < 5 microg/dL) from 24 to 72 hours in the placebo group. This was associated with a simultaneous reduction of left ventricular shortening fraction (p < 0.0001, analysis of variance; p = 0.0203, Student's t test), the necessity to increase inotropic agents (p = 0.043, analysis of variance), and an increase in serum lactate level (p = 0.049, Student's t test). During this period, serum cortisol level was maintained above the normal level (> 23 microg/dL) in the hydrocortisone group. The placebo group had a greater positive fluid balance (p = 0.027, Student's t test) and greater total body edema in the immediate postoperative period (p = 0.065, Student's t test). Blood oxygenation constantly improved, and the duration on mechanical ventilation was shorter (83.5 +/- 42.1 versus 138.2 +/- 89.7 hours; p = 0.098) in the hydrocortisone group. CONCLUSIONS: Adrenal insufficiency may occur after neonatal open heart surgery. Stress-dose hydrocortisone supplementation blunts other organ dysfunction and can be considered a legitimate pharmacotherapy in this cohort.

Cardiopulmonary Bypass↗
PubMed2005

Identification of platelet receptors for the Streptococcus gordonii DL1 sialic acid-binding adhesin.

Aggregation of human platelets by Streptococcus gordonii DL1, an interaction implicated in the pathogenesis of infective endocarditis, requires the expression of hsa, the gene encoding the sialic acid-binding adhesin (Hsa) of this organism. To identify the sialoglycoproteins on the platelet surface as the receptors for Hsa, intrinsic membrane proteins were assessed by bacterial overlay assay. S. gordonii DL1 adhered to 130-140-kDa proteins, a reaction that was abolished by neuraminidase treatment of immobilized platelet surface proteins. These sialoglycoproteins were identified as platelet glycoprotein Ib alpha (GPIbalpha ) and glycoprotein IIb (GPIIb) by immunoprecipitation with specific monoclonal antibody against each glycoprotein.

Adhesins, Bacterial↗
PubMed2005

Identification of the motilin cells in duodenal epithelium of premature infants.

BACKGROUND: The aim of the present study was to examine the presence of motilin in the duodenal epithelial cells of premature infants of < 32 weeks gestation. METHODS: Specimens from 10 deceased infants (gestational age: 26.4 +/- 2.7 weeks and birthweight: 808 +/- 303 g) were examined as subjects. All infants died of severe cardiopulmonary disorder or intraventricular hemorrhage (grade IV). The average survival period was 3.1 +/- 1.9 days. Autopsies were performed and formalin-fixed duodenums were immunostained with rabbit antiserum to motilin by the labeled streptavidin-biotin (LSAB) method. An adult duodenum obtained by pancreatoduodenectomy was also examined for the presence of motilin as a positive control specimen. An absorption test using motilin peptide was performed to prove the specificity of the binding with rabbit antiserum to motilin. RESULTS: Motilin-containing cells were detected in the adult specimen, and the binding by rabbit antiserum to motilin was completely inhibited by excess amounts of motilin peptide, indicating that this binding was specific to motilin. All 10 infants had presence of motilin antigen in the epithelial cells of their duodenums. CONCLUSION: This preliminary study indicates that the immunohistological analysis is specific to detect motilin-containing cells, and certifies the presence of motilin in duodenal epithelial cells of premature infants of < 32 weeks gestation, including one at only 22 weeks gestation.

Adult↗
PubMed2004

Single-stage repair of complete atrioventricular septal defect and coarctation of the aorta in neonate.

Controversy over patients with complete atrioventricular septal defect (CAVSD) and coarctation of the aorta (CoA) continues: whether they should be treated with a primary total correction or a staged approach utilizing initial pulmonary artery banding during neonatal period. A 17-day-old neonate with Down's syndrome underwent definitive repair of CAVSD and CoA. With the postoperative course uneventful, he was discharged from the hospital on 19th postoperative day. Single-stage repair of CAVSD and CoA appears to offer a good prognosis provided that valve morphology is amenable to repair.

Aortic Coarctation↗
PubMed2004

Open heart surgery for small children without homologous blood transfusion by using remote pump head system.

BACKGROUND: To avoid excessive hemodilution, the transfusion of a large amount of homologous blood may be required in open heart surgery for small children, which in turn, can cause a significant immunologic response. METHODS: Cardiopulmonary bypass systems with remote pump heads were used for patients weighing 5 kg or less that were undergoing ventricular septal defect repair. The procedures took place from January 1997 to August 2002. The surgery was started with bloodless prime in 122 out of 158 (77.2%) consecutive patients. Exclusion criteria were a predicted hematocrit after the initiation of bypass of less than 15%, respiratory failure or heart failure (or both), and pulmonary vascular obstructive disease. RESULTS: The mean age and body weight were 3.8 +/- 1.8 months and 4.3 +/- 0.5 kg, respectively. The priming volume was 181.0 +/- 32.5 (minimum: 130) mL. The hematocrit after cardiopulmonary bypass was initiated was 16.7% +/- 2.3%. Six patients required subsequent blood transfusion owing to postoperative complications that resulted in compromised hematopoiesis. In the rest, the hematocrit before discharge was 30.6% +/- 3.0%. Renal and liver function tests were maintained within the normal range. Patients were extubated at 5.6 +/- 2.8 hours after operation with proper oxygenation. Neurodevelopment was apparently normal. The Japanese psychomotor developmental scale assessment was given to patients without chromosomal abnormality between the ages of 1 and 3 years; the resulting score was 102.2 +/- 15.4 (mean = 100 for normal population). CONCLUSIONS: Open heart surgery was achieved without blood transfusion in the selected group of small children. The use of remote pump heads reduced the overall need for blood transfusions and possibly inflammatory reactions.

Abnormalities, Multiple↗
PubMed2004

Mutation spectrum of the PCCA and PCCB genes in Japanese patients with propionic acidemia.

Propionic acidemia (PA) is an inborn error of organic acid metabolism caused by a deficiency of propionyl-CoA carboxylase. This enzyme is composed of two non-identical subunits, alpha and beta, which are encoded by the PCCA and PCCB genes, respectively. An enzyme deficiency can result from mutations in either PCCA or PCCB. To elucidate the mutation spectrum in Japanese patients, we have performed a mutation analysis of 30 patients with PA, which included nine previously reported patients. The study revealed that 15 patients were alpha-subunit deficient and 15 patients were beta-subunit deficient. Seven novel mutations were found (IVS18-6C >G, 1746G >A, C398R, G197E and IVS18+1G >A in the PCCA; A153P and IVS9+1G >T in the PCCB). Among these Japanese patients with alpha-subunit deficiencies, 923-924insT, IVS18-6C >G, and R399Q mutations were frequent and the total allelic frequency of these three mutations combined was 56% (17/30). This is in sharp contrast to the mutation spectrum found in Caucasian patients, where no prevalent mutations have been identified. Among the beta-subunit deficiencies, there were three frequent mutations; R410W, T428I, and A153P, whose allelic frequencies were 30, 26.7, and 13.3%, respectively. In conclusion, a limited number of mutations are predominant in both PCCA and PCCB genes among Japanese patients with propionic acidemia.

Amino Acid Metabolism, Inborn Errors↗
PubMed2004

Dosage regimen of arbekacin for methicillin-resistant Staphylococcus aureus infection in newborns and infants.

BACKGROUND: Arbekacin (ABK) is an aminoglycoside antibiotic that has a dose-dependent bactericidal action. Because it inhibits the production of toxic shock syndrome toxin-1 (TSST-1) by methicillin-resistant Staphylococcus aureus (MRSA), it has attracted attention as a therapeutic drug for MRSA infection. In this study, the authors investigated the pharmacokinetics of ABK based on therapeutic drug monitoring (TDM), in order to establish an effective dosage regimen with minimal adverse reactions in MRSA infected newborns and infants. METHODS: Arbekacin was administered to nine MRSA infected newborns and infants between October 2000 and March 2002. Following the initial ABK administration, blood was collected and the blood concentration of ABK was measured. The blood concentrations of ABK were analyzed by the two-compartment model or by a model-independent method in order to elucidate the pharmacokinetics of ABK. Pharmacokinetic analysis was performed using WinNonlin Professional V3.1. RESULTS: The mean age at initial ABK administration was 24.0 +/- 26.0 days (postconceptional age: 39.2 +/- 3.9 weeks). The increase in the peak blood concentration of ABK was 2.40 +/- 0.20 microg/mL per mg ABK per kg bodyweight, showing great consistency among cases. The elimination half-life of ABK was 0.22-3.52 h in the alpha phase (T(1/2alpha)) and 2.42-33.44 h in the beta phase (T(1/2beta)), showing great variation among cases. The distribution volume was 0.75 +/- 0.13 L/kg, and systemic clearance was 0.054 +/- 0.012 L/h/kg. ABK alleviated clinical symptoms and inflammations in all cases. CONCLUSION: Nine newborns and infants with MRSA infection and various underlying diseases were successfully treated with TDM-based administration of ABK with no severe adverse reactions.

Aminoglycosides↗