Biomedical subjects
Publications and source records attributed to K Hayasaka.
We performed successful balloon pulmonary valvuloplasty (BPV) in 6 patients with pulmonary valve stenosis and atrial septal defect (ASD) accompanied by atrial left-to-right shunt without an increase of shunting immediately after BPV. It suggests that such patients should be treated by BPV initially and the need for ASD repair can be assessed during long-term follow-up.
We studied pre- and postoperative regional right and left ventricular wall motion and global ejection fraction in 18 patients with tetralogy of Fallot who had successful repair, and compared these values to those of patients with a history of Kawasaki disease as controls. Right ventricular ejection fraction was significantly lower in the preoperative group (52 +/- 4%) than that in the control group (57 +/- 4%), and that in the postoperative state (49 +/- 4%) was significantly lower than those in the control and preoperative groups. Left ventricular ejection fraction was significantly lower in the preoperative group (56 +/- 7%) than that in the control group (61 +/- 5%), while that in the postoperative state (64 +/- 6%) was significantly higher than those in the control and preoperative groups. Regional ventricular wall motion analysis revealed that shortening fractions in the tricuspid valve region were reduced in the preoperative patients and were persistent even after successful repair; those in the right ventricular outflow tract region were decreased after the correction. Regional left ventricular wall motion showed that shortening fractions in the anterolateral region were improved after the correction. We conclude that right ventricular dysfunction was present in the preoperative patients with tetralogy of Fallot and was persistent even after total correction.
The crossover breakpoints for Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) are located in the CMT1A-REP repeat flanking a 1.5-Mb region of chromosome 17p11.2-12. The precise locations of the breakpoints are heterogeneous, and we analyzed the relative frequency distribution of breakpoints in 33 unrelated Japanese CMT1A and 3 unrelated HNPP families. The CMT1A-REP repeat region was divided into five regions, A, B, C, D and E, based on restriction site differences between the proximal and distal CMT1A-REP repeats. The frequency distribution of breakpoints within the CMT1A-REP repeat in the Japanese patients was 3% in region A, .78% in B/C and 19% in D, which is similar to that in Caucasian patients. This result also indicates that an 8-kb region defined by region B/C is a recombinational hotspot within the CMT1A-REP repeat in Japanese patients.
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We report on a sporadic case of hitherto unknown lethal skeletal dysplasia. The cardinal clinical manifestations consisted of frontal bossing, cloudy corneae, low nasal ridge, and micrognathia, hypoplastic thorax, and rhizomelic micromelia. Laryngoscopy and neck CT disclosed laryngeal stenosis, and brain CT demonstrated hypoplasia of the corpus callosum. Skeletal survey demonstrated hypoplasia of facial bones and short skull base, extremely severe platyspondyly, hypoplastic ilia, and delayed epiphyseal ossification and rhizomelic shortness of tubular bones. The long bones appeared overtubulated with exaggerated metaphyseal flaring. The humeri were particularly short and bowed. Bowing of the radii and ulnae with subluxation of radial heads presented as a Madelung-like deformity. Unlike the long bones, the short tubular bones were not short and normally modeled. The skeletal changes were superficially similar to those in a group of lethal platyspondylic chondrodysplasias, but were inconsistent with any known subtypes of this group or other lethal skeletal dysplasias.
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We have previously reported that heterozygosity for myelin Po gene mutations were associated with Charcot-Marie-Tooth disease type 1B (CMT1B) or Dejerine-Sottas disease. We investigated the Po gene in a family with clinical Dejerine-Sottas disease and found two children were homozygous for a deletion of Phe 64. The parents were heterozygous first cousins with subclinical CMT1B and slow nerve conduction velocities. These results suggest that the effect of homozygous Phe 64 deletion on impairment of myelination is dosage-dependent. Clinical phenotype and/or myelin impairment may be determined both by the type of mutation and by the dosage of mutated gene.
A 46-year-old housewife had complaints of insidiously progressive muscle weakness and paresthesia in the distal lower limbs. On neurological examination, a slight to moderate degree of muscle weakness with slight atrophy was observed in the bilateral intrinsic hand muscles. A severe degree of muscle weakness with moderate atrophy was observed in tibialis anterior, gastrocnemius and soleus muscles. Muscle stretch reflexes were decreased in the upper limbs and absent in the lower limbs, without pathologic reflexes. She had a steppage gait. Vibratory sensation was slightly decreased in the hands and moderately decreased in the feet. Touch, pain and temperature sensations were also moderately decreased only in the feet. On laboratory examination, glycosuria (5.6g/dl) was noted. Fasting blood sugar was 226mg/dl with an elevated hemoglobin A1C level (12.7%). The right median motor and sensory nerve conduction velocities were 14.8 and 20.3 m/sec, respectively, with a markedly prolonged distal latency. No muscle action potential was obtained from stimulation of the right tibial nerve. Also, no nerve action potential was elicited from stimulation of the right sural nerve. A fascicular biopsy of the right sural nerve revealed the presence of both demyelinated and remyelinated axons, and an onion-bulb formation with a marked decrease in the density of the myelinated fibers. Based on the neurological examination and nerve conduction studies of the family members, a younger sister, younger brother and an elder daughter of the proband were found to be affected by demyelinating polyneuropathy. Diabetes mellitus was not found among the family members with laboratory evidences of demyelinating polyneuropathy. Based on the family history, an uncle on the mother's side of the proband, the proband's grandmother and a younger daughter of a proband's brother were considered to be affected. The uncle and grandmother had diabetes mellitus. Therefore, we concluded that this family had HMSN type I with autosomal dominant inheritance. In the studies on fluorescence in situ hybridization, and restriction fragment length polymorphism of the genomic DNA of the proband, a DNA duplication in the 17p11.2-12 region was not observed. However, the direct sequencing analysis of DNA fragments from genomic DNA encoding the Po gene of the proband revealed a substitution of histidine for arginine at the codon 98 in the extramembranous domain of Po. She was heterozygous for the mutant allele and normal allele. Alterations in the tertiary structure of the extramembranous domain of Po may result in an impairment of the peripheral myelin compaction. This is the second Japanese family with the same mutation (Arg98-->His) of myelin Po as reported previously by us, and this type of case is rare in the literature. Therefore, the mutation at the codon 98 may play a critical role in the development of the myelin abnormality in HMSN type IB.
Most of Charcot-Marie-Tooth (CMT) 1 families are associated with a duplication in chromosome 17p11.2-p12, which includes the gene encoding peripheral myelin protein-22 (PMP-22). Point mutations of the Po gene have been identified in a few of the CMT 1 families in whom no duplication was found. We investigated a new mutation of the Po gene in one of those families. A to G substitution of nucleotide 389 in exon 3 resulted in Lys 131 Arg substitution. This structural change of extracellular domain of Po would alter the function of Po and result in an impairment of peripheral myelin compaction.
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The authors report on 3-year-old-girl with neuroblastoma complicated by severe hypertension and cardiac failure. She had cardiomegaly and pleural and pericardial effusions. Echocardiogram showed left ventricular hypertrophy and decrease of the left ventricular ejection fraction to 0.36 (normal > .40). Abdominal computed tomographic scan indicated a 7 x 7-cm tumor in the left suprarenal area. There was a marked increase in catecholamines and metabolites in her body fluids. After hypertension was controlled with doxazosin (a long-acting alpha 1 adrenergic blocker), her cardiac function gradually improved. A tumor was surgically removed and diagnosed as a poorly differentiated ganglioneuroblastoma. Preoperative differentiation between neuroblastoma and pheochromocytoma was not possible on the basis of catecholamine analysis or imaging studies including computed tomography scan and magnetic resonance imaging. It is important to control hypertension quickly in the patients with catecholamine-induced cardiomyopathy to facilitate surgical intervention for diagnosis and treatment.
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The Chediak-Higashi syndrome is characterized by partial albinism and recurrent infections with giant granules in granulocytes. This syndrome has been proposed to have a defect in vesicular transport. Rab 4 is a member of a family of Ras-related small GTP-binding proteins, which has been mapped in the locus of the Chediak-Higashi syndrome. We isolated a full length cDNA of rab 4 from a cDNA library of mouse liver. The clone is 1428 base pairs (bp) in length and contains a 639 bp open reading frame encoding a polypeptide of 213 residues. The deduced amino acid sequence is highly homologous to rab 4 from rat and human. We analyzed rab 4 as a candidate gene of the beige mouse, but we could not find any change in the sequence of the coding region of rab 4 mRNA.
We determined the nucleotide sequences of an 896-base pair region of mitochondrial DNA (mtDNA) from 20 primates representing 13 species of macaques, a baboon, and a patas. We compared these sequences and the homologous sequences from four macaques and a human against each other and deduced the phylogenetic relationships of macaques. The results from the phylogenetic analyses revealed five groups among the macaques: (1) Barbary macaque, (2) two species of Sulawesi macaques, (3) Japanese, rhesus, Taiwanese, crab-eating, and stump-tailed macaques, (4) toque, pig-tailed, and lion-tailed macaques, and (5) Assamese and bonnet macaques. The phylogenetic position of Tibetan macaque remains ambiguous as to whether it belongs to the fourth or fifth group. Phylogenetic trees revealed that Barbary macaque diverged first from the other Asian macaques. Subsequently, the four groups of Asian macaques diverged from one another in a relatively short period of time. Within each group, most of the species diverged in a relatively short period of time following the divergence of the groups. Assuming that the Asian macaques diverged from the outgroup Barbary macaque three million years ago (MYA), the divergence times among groups of Asian macaques were estimated at 2.1-2.5 MYA and within groups at 1.4-2.2 MYA. The intraspecific nucleotide diversity observed among three rhesus macaques was so large that they did not form a monophyletic cluster in the phylogenetic trees. Instead, one of them formed a cluster with Japanese and Taiwanese macaques, whereas the other two formed a separate cluster. This implies that either polymorphisms of mtDNA sequences that existed before the divergence of these three species (ca. 700,000 years ago) have been retained in rhesus macaques or introgression has occurred among the three species.
In the present study, we focus on the proliferation of human arterial smooth muscle cells (SMCs) from NIDDM patients (DM-SMCs) to clarify the reactivity to the growth factor(s) in fetal calf serum (FCS) and the factor(s) secreted by T-cells. The proliferation of DM-SMCs was significantly greater than SMCs from nondiabetic patients (nonDM-SMC). DM-SMC conditioned medium (DM-condMed) increased the growth of nonDM-SMCs. These results suggest that the growth factor is secreted from DM-SMCs as an autocrine system, which increases the proliferation of nonDM-SMCs. T-cells increased DNA synthesis of SMCs, and DM-SMCs strikingly reacted to T-cells. The present results support a function of T-cells in stimulating SMC growth. In conclusion, human arterial SMC proliferation is increased in diabetes in the same fashion as in experimentally induced diabetes in animals through responses to growth factors and an increased autocrine system. These results provide a mechanism for the increase in atherosclerotic disease in diabetes.
Nucleotide sequences of the major noncoding (D-loop) region of human mtDNA from five East Asian populations including mainland Japanese, Ainu, Ryukyuans, Koreans, and Chinese were analyzed. On the basis of a comparison of 482-bp sequences in 293 East Asians, 207 different sequence types were observed. Of these, 189 were unique to their respective populations, whereas 18 were shared between two or three populations. Among the shared types, eight were found in common between the mainland Japanese and Koreans, which is the largest number in the comparison. The intergenic COII/tRNA(Lys) 9-bp deletion was observed in every East Asian population with varying frequencies. The D-loop sequence variation suggests that the deletion event occurred only once in the ancestry of East Asians. Phylogenetic analysis revealed that East Asian lineages were classified into at least 18 monophyletic clusters, though lineages from the five populations were completely intermingled in the phylogenetic tree. However, we assigned 14 of the 18 clusters for their specificity on the basis of the population from which the maximum number of individuals in each cluster was derived. Of note is the finding that 50% of the mainland Japanese had continental specificity in which Chinese or Koreans were dominant, while < 20% of either Ryukyuans or Ainu possessed continental specificity. Phylogenetic analysis of the entire human population revealed the closest genetic affinity between the mainland Japanese and Koreans. Thus, the results of this study are compatible with the hybridization model on the origin of modern Japanese. It is suggested that approximately 65% of the gene pool in mainland Japanese was derived from the continental gene flow after the Yayoi Age.
Charcot-Marie-Tooth neuropathy (CMT) is the most common inherited peripheral neuropathy. CMT is classified into type types on the basis of pathological and electrophysiological findings: type 1(CMT1), characterized by decreased nerve conduction velocities and by "onion bulb" formation: type 2(CMT2), in which nerve conduction velocities are normal and "onion bulb" formations are rarely seen. CMT1 loci map to chromosome 17 (CMT1A), chromosome 1(CMT1B), another unknown autosome (CMT1C) and the X chromosome (CMTX). Recent work has identified the gene products corresponding to CMT1A, CMT1B and CMTX as peripheral myelin protein-22(PMP22), Po and connexin 32, respectively. Dejerine-Sottas disease has been identified as being caused by the mutation of PMP-22 or Po gene.
The major neuritogenic protein of peripheral nerve myelin is the P2 protein. Human P2 is a candidate autoantigen in inflammatory demyelinating diseases of the peripheral nervous system. Since human P2 is not readily available, we produced full-length recombinant human P2 protein (rhP2) in Escherichia coli. RhP2 was recognized by neuritogenic rat T cell lines and induced experimental autoimmune neuritis in Lewis rats. Production of rhP2 allowed the generation of human T cell lines reactive to the autologous protein. Studies of human T cell autoreactivity as well as efforts to use hP2 as a tolerogen will be facilitated by the large-scale expression of rhP2.