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Biomedical subjects

K Yabuta

Publications and source records attributed to K Yabuta.

At least 19 recordsLinked to original sources
PubMed2001

Gelastic seizures in clusters in a case of West syndrome after perinatal hypothalamic hemorrhage.

We describe a 4-month-old Japanese infant with West syndrome with gelastic seizures in clusters. Smile developed around 3 months and gradually increased in frequency and intensity. Positron emission tomography showed hypoperfusion in bilateral hypothalamus. Interictal electroencephalogram (EEG) showed hypsarrythmia. Simultaneous video/EEG monitoring was performed. At first, a smile-like episode developed every several seconds, gradually increased to an abrupt flexion of the neck and extremities, and gradually decreased to a smile-like episode at the end. Ictal EEG revealed desynchronization. ACTH was effective. Smiles are common emotional responses in infancy. However, EEG and neuroimaging should be considered in a case of perinatal asphyxia and delayed development.

Asphyxia Neonatorum↗
PubMed1999

Analysis of the stable levels of messenger RNA derived from different polymorphic alleles in the vitamin D receptor gene.

The association between polymorphisms in the vitamin D receptor (VDR) gene and bone mineral density (BMD) has been studied by many investigators. However, the question of how polymorphisms in the gene modulate the function of the VDR remains to be answered. To address this issue, we examined the mRNA levels of the VDR in relation to polymorphisms. First, we compared the levels of mRNA between the allele with the polymorphic TaqI-digestive site (t) and nondigestive site (T) located at exon 9 of the VDR gene determined by reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was extracted from peripheral mononuclear cells in volunteers whose genotype is Tt. After the amplification of cDNA by PCR, the amplified fragments were digested by TaqI. The digested (t) and undigested (T) fragments were visualized by ethidium bromide and semiquantified by an image analyzer. In 24 subjects, the mRNA levels of allele t were significantly higher than those of allele T (1.35 fold, P < 0.001). Second, the VDR mRNA levels were estimated by competitive RT-PCR in 60 healthy subjects (35TT, 24Tt, 1 tt). The competitive template was 47 bases shorter than the product of the wild-type gene. After RT-PCR, the mRNA level was determined by a comparison with the competitive fragments. No significant difference in the mRNA level was observed between two groups (1.75 +/- 0.84 and 1.65 +/- 0.99 10(-13)mol/g total RNA in TT and Tt, respectively). In addition, no significant relationship was observed between the VDR mRNA levels and BMD in the 23 subjects whose BMD data were available. In conclusion, higher mRNA levels of allele t than T were detected, but the difference did not result in higher levels of VDR mRNA in subjects with the Tt genotype compared to those with the TT genotype.

Adult↗
PubMed1999

Induction of anaphylaxis in mouse intestine by orally administered antigen and its prevention with soluble high affinity receptor for IgE.

Early symptoms of food allergy, including diarrhea, are caused by IgE-mediated anaphylactic reactions. To clarify the mechanisms of IgE-mediated anaphylactic reactions in the intestine induced by orally administered antigen, a mouse model was established by s.c. implantation of a murine hybridoma capable of producing monoclonal anti-trinitrophenyl IgE antibody. Morphologic and immunologic changes in the intestine, as well as the effect of the soluble high affinity IgE receptor alpha chain, were investigated after oral challenge with antigen in this mouse model. Diarrhea, a decrease in s.c. blood flow, an increase in vascular permeability, a substantial increase in serum histamine levels, and noticeable infiltration of mast cells and IgE-bearing cells into the lamina propria were observed around 30 min after antigen challenge. However, these changes were efficiently prevented by pretreatment of the mice with the soluble high affinity IgE receptor alpha chain. These findings suggested that oral administration of antigen actually induced anaphylactic shock in our mouse model. This reaction was most likely to be mediated by mast cell activation, in response to the IgE-antigen complex, and a soluble form of the high-affinity IgE receptor efficiently prevented this IgE-mediated anaphylactic reaction by trapping free IgE.

Administration, Oral↗
PubMed1998

Spring coil retraction in coil occlusion of persistent ductus arteriosus.

AIMS: To present the short and intermediate term results of coil occlusion of persistent ductus arteriosus and the results of radiographic measurements of spring coils implanted to treat patent ducts. PATIENTS: 22 children underwent coil occlusion. Their ages ranged from 2 years 9 months to 12 years 10 months (mean (SD) age, 6.5 (3.6) years). The duct diameter ranged from 1.0 to 3.5 mm at the narrowest point (mean 2.6 (0.7) mm). In 11 of the children regular coils were implanted using the non-attached system, while in the other 11 the detachable coil embolisation system was used. RESULTS: 12 children (55%) had no significant residual leaks immediately after procedures involving a single coil delivery. The remaining 10 (45%) had residual leaks immediately after the procedure, although no patient with a large duct showed residual leakage 18 months after the procedure. Radiographic measurement of the coils showed that all implanted coils retracted to 65-85% of their original size immediately after occlusion. This retraction was more evident in patients showing spontaneous closure of the residual shunt or having a coil 8 mm in diameter. CONCLUSIONS: Coil embolisation is an acceptable method for occluding persistent ductus arteriosus. Retraction of implanted coils is common in the follow up period. Such retraction may be related to spontaneous closure of residual shunt after embolisation.

Child↗
PubMed1998

A case of acquired zinc deficiency in a mature breast-fed infant.

We describe a 5-month-old Japanese infant with zinc deficiency, who was exclusively breast-fed and showed improvement after zinc supplement was administered. His serum zinc level and the zinc content of breast milk from his mother were extremely low, although the mother's serum zinc level was within normal limits. Zinc deficiency would not be latently uncommon in a mature breast-fed infant.

Alopecia↗
PubMed1997

Apoptosis as a possible cause of wall thinning in end-stage hypertrophic cardiomyopathy.

A 15-year-old boy with hypertrophic cardiomyopathy died of congestive heart failure with progressive left ventricular wall thinning with poor systolic function. Microscopic examination revealed patchy fibrosis in the ventricular myocardium with wall thinning, and immunohistochemical evaluation of apoptosis showed apoptotic cells and bodies in the destroyed myocytes along the border between the fibrotic area and myofibril.

Adolescent↗
PubMed1997

Four novel KVLQT1 and four novel HERG mutations in familial long-QT syndrome.

BACKGROUND: Familial long-QT syndrome (LQTS) is characterized by prolonged ventricular repolarization. Clinical symptoms include recurrent syncopal attacks, and sudden death may occur due to ventricular tachyarrhythmias. Three genes responsible for this syndrome (KVLQT1, HERG, and SCN5A) have been identified so far. We investigated mutations of these genes in LQTS families. METHODS AND RESULTS: Thirty-two Japanese families with LQTS were brought together for screening for mutations. Genomic DNA from each proband was examined by the polymerase chain reaction-single-strand conformation polymorphism technique followed by direct DNA sequencing. In four of the families, comprising 16 patients, mutations were identified in KVLQT1; five other families (9 patients) segregated mutant alleles of HERG. All 25 of these patients carried the specific mutations present in their respective families, and none of 80 normal individuals carried these alleles. Mutations were confirmed by endonuclease digestion or hybridization of mutant allele-specific oligonucleotides. No mutation in SCN5A was found in any family. CONCLUSIONS: We identified nine different mutations among 32 families with LQTS. Eight of these were novel and account for 25% of all types of mutations reported to date. Such a variety of mutations makes it difficult to screen high-risk groups using simple methods such as endonuclease digestion or mutant allele-specific amplification.

Alleles↗
PubMed1997

A case of infantile Dubin-Johnson syndrome with high CT attenuation in the liver.

We report a case of Dubin-Johnson syndrome (DJS) with severe infantile cholestasis and elevated computed tomography (CT) attenuation of the liver. Increased levels of urinary coproporphyrin I were found as well as pigment granules in the hepatocytes and hepatosteatosis. The CT attenuation was markedly higher in the liver of this patient at the ages of 3 and 7 months than in the spleen or kidneys. This high attenuation may be a finding specific to infantile DJS and, therefore, abdominal CT may be helpful in the diagnosis.

Biopsy, Needle↗
PubMed1997

Late persistent expressions of ICAM-1 and VCAM-1 on myocardial tissue in children with lymphocytic myocarditis.

BACKGROUND: Both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) have been implicated in cardiac allograft rejection. However, there is little information about the relationship between the expression of these adhesion molecules and myocarditis in children. METHODS AND RESULTS: Immunoreactivities of ICAM-1 and VCAM-1 were examined by enzyme immunoassay in 31 biopsy specimens obtained from 11 pediatric patients with biopsy-proven myocarditis or cardiomyopathy. Five of the 11 patients had clear evidence of acute myocarditis. The other 6 had ECG abnormalities identified by mass screening for heart disease, and subsequently had been histologically diagnosed as having non-specific cardiomyopathy. The period between onset of myocarditis or identification of ECG abnormality and immunohistochemical studies was 23 to 60 days and 8 months to 3 years, respectively. Expression of ICAM-1 and VCAM-1 was assessed by counting ICAM-1 and VCAM-1 positive vessels and dividing by the total number of vessels. ICAM-1 was significantly present on 81% (P < 0.01) of myocardial tissue samples in the 5 patients with healing-stage acute myocarditis, and on 45% (P < 0.05) in the remaining 6 patients with non-specific cardiomyopathy, compared with 24% in control specimens obtained from right ventricular muscle resected at surgery for tetralogy of Fallot. VCAM-1 was also present on 50% (P < 0.05) of the samples from the 5 patients with acute myocarditis, but was not present in those with non-specific cardiomyopathy. CONCLUSION: This persistent expression of ICAM-1 suggests that myocardial cell damage may persist immunologically for a long period in myocarditis. In addition, immunostaining for these adhesion molecules may be diagnostic value in clinically silent lymphocytic myocarditis and chronic cardiomyopathy.

Adolescent↗
PubMed1997

Characterization of low-density lipoprotein subclasses in children.

Low-density lipoprotein (LDL) particles are heterogeneous in density, size, and chemical composition, and this heterogeneity is thought to be genetically influenced. In the present study, plasma LDL subclasses in 248 children aged 7 to 13 years were analyzed by gradient gel electrophoresis. The prevalence of small dense LDL (SDLDL), a potent atherogenic LDL, was 9.3%, which is lower than that reported in adults. Furthermore, children with this LDL subclass showed increased body fatness and dyslipidemia, including elevated plasma triglyceride and apolipoprotein (apo) B concentrations and decreased plasma high-density lipoprotein (HDL) cholesterol and apo A-I concentrations, compared with children without this phenotype. These findings suggest that in addition to genetic factors, environmental factors that affect these cardiovascular risk factors may also influence expression of the SDLDL subclass.

Apolipoprotein A-I↗
PubMed1997

Lipoprotein(a) phenotypes in Japanese children: a cohort study.

BACKGROUND: Elevated serum lipoprotein(a) [Lp(a)] concentrations have been demonstrated to be associated with cardiovascular diseases due to premature atherosclerosis. However, the association of Lp(a) phenotypes with the development of these diseases remains largely unexplored. METHODS: We analyzed the population-based frequencies of serum Lp(a) phenotypes in 269 Japanese children aged 8-13 years in one community. According to the different apolipoprotein(a) [apo(a)] electrophoretic mobilities, Lp(a) was classified into seven single-band and respective double-band phenotypes. Each individual expressed a single (homozygotic) or a double band (heterozygotic). RESULTS: The serum Lp(a) concentration frequency distribution was skewed toward lower levels with a mean +/- SD of 15.5 +/- 18.0 mg/dl and a median of 11.0 mg/dl. The Lp(a) phenotype frequencies revealed that the frequency of double-band phenotype expression (55%) was higher than that of single bands (44%) and that the frequency of phenotypes representative of low molecular weight apo(a) was very low (2%). The mean serum Lp(a) concentration of the double-band-expressing subjects was higher than that of subjects with the single-band phenotype (20.1 +/- 19.9 vs. 10.5 +/- 15.9 mg/dl, p < 0.01). CONCLUSIONS: These findings of Lp(a) phenotypes in children seemed to differ from those in Japanese adults in another study; contrary to expectation, the predominant Lp(a) phenotypes found in children were those frequently associated with cardiovascular diseases in adults. Thus, it is speculated that children whose Lp(a) phenotypes remain unchanged during the transition to adulthood may show an increased susceptibility to cardiovascular disease, although the nutritional effects on the Lp(a) phenotypes cannot be neglected.

Adolescent↗