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Biomedical subjects

T Seki

Publications and source records attributed to T Seki.

At least 451 records · Page 25Linked to original sources
PubMed1991

The persistent expression of a highly polysialylated NCAM in the dentate gyrus of the adult rat.

The expression of a highly polysialylated form of the neural cell adhesion molecule (NCAM-H), often termed 'embryonic NCAM', has been investigated in the hippocampal formation of developing and adult rats. To determine the immunohistochemical localization of NCAM-H, a monoclonal antibody that reacts with the polysialic acid portion of NCAM-H was used. In the late embryonic and early postnatal periods, immunoreactivity for NCAM-H was found throughout the hippocampal formation, except for the ventricular layer. Thereafter, the immunoreactivity gradually decreased and almost vanished in most parts in the adult. However, a strong immunoreactivity remained on a number of cells in the dentate gyrus of adult rats, particularly in the deepest part of the granular layer. The immunoreactive arborized dendrites, mostly arising from the primary apical pole of the granule cells, were found to enter the molecular layer. The mossy fibers also were positive. Electron-microscopic examination of the hilus portion showed that the immunoreactivity was detected on the plasma membrane of some axons in the mossy fiber bundles. Since postnatal neurogenesis is known to continue into adulthood in the deepest part of the granule cell layer of the dentate gyrus, these results suggest that, in the adult dentate gyrus, NCAM-H is expressed by newly generated granule cells, and that the NCAM-H-expressing new cells may participate in the formation of new neural circuits.

Aging↗
PubMed1991

Steroid-responsive painful ophthalmoplegia in childhood: sphenoid sinusitis presenting as Tolosa-Hunt syndrome.

A childhood case of painful ophthalmoplegia which responded well to steroids was described. Although the clinical features suggested Tolosa-Hunt syndrome (THS), serial magnetic resonance imagings (MRI) revealed ethmoid and sphenoid sinusitis in this 7-year-old boy. It was considered that multiple factors such as allergy, viral infection and swimming predisposed him to develop severe sinusitis and gave rise to his painful ophthalmoplegia.

Child↗
PubMed1991

Sphingosine-1-phosphate, a novel lipid, involved in cellular proliferation.

Sphingosine, a metabolite of membrane sphingolipids, regulates proliferation of quiescent Swiss 3T3 fibroblasts (Zhang, H., N. E. Buckley, K. Gibson. and S. Spiegel. 1990. J. Biol. Chem. 265:76-81). The present study provides new insights into the formation and function of a unique phospholipid, a metabolite of sphingosine, which was unequivocally identified as sphingosine-1-phosphate. The rapid increase in 32P-labeled sphingosine-1-phosphate levels induced by sphingosine was concentration dependent and correlated with its effect on DNA synthesis. Similar to the mitogenic effects of sphingosine, low concentrations of sphingosine-1-phosphate stimulated DNA synthesis and induced pronounced morphological alterations. Both sphingosine and sphingosine-1-phosphate stimulated DNA synthesis in cells made protein kinase C deficient by prolonged treatment with phorbol ester and sphingosine still elicited similar increases in sphingosine-1-phosphate levels in these cells. Although both sphingosine and sphingosine-1-phosphate acted synergistically with a wide variety of growth factors, there was no additive or synergistic effect in response to a combination of sphingosine and sphingosine-1-phosphate. Using a digital imaging system for measurement of calcium changes, we observed that both sphingosine and sphingosine-1-phosphate are potent calcium-mobilizing agonists in viable 3T3 fibroblasts. The rapid rise in cytosolic free calcium was independent of the presence of calcium in the external medium, indicating that the response is due to the mobilization of calcium from internal store. Our results suggest that sphingosine-1-phosphate may be a component of the intracellular second messenger system that is involved in calcium release and the regulation of cell growth induced by sphingosine.

Animals↗
PubMed1991

Isolation and characterization of cDNA for an androgen-regulated mRNA in the flank organ of hamsters.

Flank organs of hamster are useful for studying androgen-dependent growth of hair follicles and sebaceous glands. To elucidate the mechanism of gene expression regulated by androgen, we constructed a cDNA library from flank organs of male hamsters and screened by a differential hybridization method using cDNA probes from normal and castrated males. We isolated a cDNA clone, termed FAR-17a, whose expression was found to be highly sensitive to androgen. FAR-17a mRNA of 1.8 kb was reduced after castration and reappeared after testosterone treatments. Among several tissues examined, FAR-17a gene was expressed at a high level in flank organ and a low level in testis and earlobe. FAR-17a probe detected a few fragments in genomic DNA of hamster, mouse, suncus, pig, and human, suggesting that this gene is phylogenetically conserved. The sequence of FAR-17a cDNA predicts a protein of 231 amino acids (27,216 daltons) having basic properties. The deduced protein has no significant homologies to proteins previously described.

Amino Acid Sequence↗
PubMed1991

A case of erythromelanosis follicularis faciei with a unique distribution.

A 16-year-old Japanese boy with erythromelanosis follicularis faciei (EFF) with an unusual distribution is described. The clinical features of classic EFF consist of reddish-brown discoloration of the skin with fine follicular hyperkeratosis in the preauricular areas, and occasionally on the temples and the lateral aspects of the neck. The present case is unique in that similar lesions also occurred on the auricles and eyebrows. Both light and electron microscopic findings of the lesions were consistent with the diagnosis of EFF.

Adolescent↗
PubMed1991

Modified PCR-RFLP method for HLA-DPB1 and -DQA1 genotyping.

We previously developed a new technique for HLA class II genotyping by digestion of polymerase chain reaction-amplified genes with restriction endonucleases (PCR-RFLP method). This PCR-RFLP method is an efficient and convenient typing technique for class II alleles. However, small fragments or bands located close to each other on polyacrylamide gels sometimes prevent precise analysis of the RFLP bands. Furthermore, the restriction enzymes we have reported in the previous papers are not sufficient to identify the genotypes of all heterozygous individuals. Here, we report an improved PCR-RFLP method using some informative restriction enzymes which have either a single cleavage site or, alternatively, no cleavage site in the amplified DNA region, depending on the HLA alleles, making reading of RFLP band patterns much easier. Each second exon of the HLA-DQA1 or -DPB1 gene was selectively amplified from genomic DNAs of 70 HLA-homozygous B-cell lines and 100 healthy Japanese by PCR. Amplified DNAs were digested with restriction endonucleases and then subjected to electrophoresis assaying simply for cutting, or no cutting, of the DNA. ApaLI, HphI, BsaJI, FokI, MboII and Mn1I can discriminate eight alleles of the DQA1 gene. Similarly 19 alleles of the DPB1 gene can be discriminated with Bsp1286I, FokI, DdeI, BsaJI, BssHII, Cfr13I, RsaI, EcoNI, and AvaII enzymes. This modified PCR-RFLP method can be successfully applied to heterozygotes. Thus, the method is technically simpler and more practical for routine HLA typing work than our previous PCR-RFLP method.

Alleles↗
PubMed1991

Monotherapy for childhood epilepsies with zonisamide.

Zonisamide was tried on 44 children, 18 girls and 26 boys, from 8 months to 15 years of age at the start of the trial. In 6 children the drug has been stopped because of side effects. The drug was introduced at a dose of 2-4 mg/kg/day and increased to 12 mg/kg/day unless a satisfactory response occurred at a lower dose. A 100% control of seizures was achieved in 5 of 5 cases of idiopathic generalized epilepsies, in 7 of 8 cases of symptomatic generalized epilepsies, in one of one case of idiopathic partial epilepsies, and in 17 of 24 cases of symptomatic partial epilepsies. The main side effect was drowsiness, especially during the introduction.

Administration, Oral↗
PubMed1991

Five genes involved in self-transmission of pSN22, a Streptomyces plasmid.

An 11-kbp multicopy plasmid, pSN22, was isolated from Streptomyces nigrifaciens SN22. pSN22 is self-transmissible (conjugative), is maintained stably in S. lividans, and forms pocks in a wide range of Streptomyces strains. Mutational analyses showed that a fragment of pSN22 contained five genes involved in plasmid transfer and pock formation. traB was essential for plasmid transfer. traA was required for pock formation, but not for plasmid transfer. spdA or spdB were concerned with pock size; mutations in these genes decreased pock size. The fifth gene, traR, could be deleted together with other genes to give nontransmissible plasmids, but plasmids with insertions or deletions only within traR became nonviable. traR is probably needed to counterbalance the lethal effects of another plasmid gene. Transfer of pSN22 promoted the cotransfer of nontransmissible plasmids and enhanced chromosome recombination between the host and recipient strains, suggesting that plasmid transfer accompanies cytoplasmic mixing.

Conjugation, Genetic↗
PubMed1991

Regulation and function of the Streptomyces plasmid pSN22 genes involved in pock formation and inviability.

pSN22 is an 11-kb multicopy plasmid from Streptomyces nigrifaciens which is being studied in Streptomyces lividans. A segment of about 7 kb of pSN22 contains five genes involved in conjugation. Three of them, traA, traB, and traR, are essential for plasmid transfer and for the mobilization of chromosomal markers (fertility), while the remaining two genes, spdA and spdB, merely enhance the efficiency of plasmid transfer, resulting in the formation of larger pocks. In vitro promoter-probing experiments identified a 550-bp BglII-SmaI DNA fragment with promoter activity in both orientations; Northern (RNA blot) hybridization identified corresponding divergent transcripts of 1 and 5.2 kb for traR and the traA-traB-spdB operon, respectively. The traR gene product repressed its own transcription and also the transcription of the traA-traB-spdB operon. Plasmids containing a functional traB gene could not "survive" without traR being present in the same cell either in cis or in trans, presumably because unregulated expression of traB is lethal to the host. Plasmids with a functional traA gene but without traR had a low transformation efficiency and inhibited the growth of host cells.

Blotting, Northern↗
PubMed1991

Membranous lipodystrophy: MR imaging appearance of the brain.

Five patients with membranous lipodystrophy (lipomembranous polycystic osteodysplasia with progressive dementia) underwent magnetic resonance (MR) imaging of the brain. T2-weighted MR images showed atrophied cerebral white matter with dilated ventricles; increased signal intensity of the white matter; and decreased signal intensity of the thalamus, putamen, caudate nucleus, and cerebral cortex. Although each single finding is not specific, the combination of the above MR findings when coupled with skeletal lesions strongly suggests this rare disease.

Adult↗
PubMed1991

Hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with internal mammary arteries in children with Kawasaki disease.

BACKGROUND: Saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts have been used for coronary artery bypass grafting. In adult patients with bypass grafting for atherosclerotic coronary artery disease, IMA grafts have been reported to have long-term patency; however, results are conflicting on whether the graft is sufficient to meet increased myocardial oxygen demand during exercise. There have been no studies on hemodynamics and blood flow during exercise after bypass grafting with IMA in pediatric patients with Kawasaki disease. METHODS AND RESULTS: We studied 17 pediatric patients with Kawasaki disease (average age, 7.5 +/- 3.1 years), who underwent coronary artery bypass grafting with the IMA. The average number of coronary artery bypass grafts was 2.1 +/- 0.7/patient. For all patients, the left IMA was anastomosed to the left anterior descending coronary artery; for eight patients, the right IMA was also anastomosed to the right coronary artery. In addition, 11 SVGs were used. The postoperative patency rates after 1 month were 100% with the IMA graft and 91% with SVG. One year after the operation, the patency rates were 100% with IMA and 50% with SVG. Hemodynamics during exercise were measured with a bicycle ergometer, and coronary sinus blood flow was measured by the continuous thermodilution method in six patients. The relation between delta LVEDP (the difference between left ventricular end-diastolic pressure at rest and during exercise) and delta SVI (the difference between the stroke volume index at rest and during exercise) was analyzed. Four of six patients had reduced cardiac function before operation (delta LVEDP, positive; delta SVI, negative). However, after the operation, all patients demonstrated improvements in cardiac function during exercise (delta LVEDP, positive; delta SVI, positive). Coronary sinus flow per left ventricular mass increased after operation from 70 +/- 46 to 87 +/- 56 ml/min at rest (p less than 0.05) and from 139 +/- 118 to 183 +/- 150 ml/min during exercise (p less than 0.05). CONCLUSIONS: In conclusion, this study reveals improvements in both hemodynamics and coronary blood flow during exercise after coronary artery bypass grafting with IMA grafts in pediatric patients with Kawasaki disease.

Adolescent↗
PubMed1991

Controlled release of 5-fluoro-2'-deoxyuridine by the combination of prodrug and polymer matrix.

Poly(L-lactic acid) (L-PLA) microspheres containing 5-fluoro-2'-deoxyuridine (FUdR) or its ester prodrugs with saturated aliphatic acids (FUdR-Cn, n = 2, 3, 4, 5, 6, 8, 10 and 12) were prepared. The physicochemical and biological properties and antitumor activity of the L-PLA microspheres were studied. The lipophilicity of FUdR-Cn was increased by prolonging its acyl-promoieties. FUdR-C5, FUdR-C6, FUdR-C8, FUdR-C10 and FUdR-C12 showed almost complete incorporation into the microspheres, while incorporation of hydrophilic FUdR and FUdR-C2 was poor. The sustained release of FUdR from the microspheres containing FUdR-C4, FUdR-C5 and FUdR-C6 was obtained in the presence of esterase, and higher antitumor activity against P388 leukemia was observed in vivo. On the other hand, the release rates of FUdR from the microspheres containing FUdR-C10 and FUdR-C12 were very small, and their antitumor activity was much smaller than that of the free prodrug suspension. Effects of the susceptibility to enzymatic hydrolysis and the physiocochemical properties of prodrugs on the release profiles of FUdR from spheres were discussed.

Animals↗
PubMed1991

[A case of severe periodontal disease in adolescence associated with hypophosphatasia].

Hypophosphatasia is an inherited disorder characterized by defective bone mineralization, deficiency of alkaline phosphatase (ALP) activity, increased excretion of phosphoethanolamine (PEA) in the urine and premature loss of the deciduous teeth. A male hypophosphatasia patient aged 15 years 6 months, with premature exfoliation of the deciduous teeth and manifesting severe periodontal destruction in the permanent dentition, was examined. Antibody titers against seven strains by the enzyme-linked immunosorbent assay (ELISA), monocyte and neutrophil chemotaxis studies and cellular immunity tests were performed. Low levels of ALP in serum and PEA in the urine were found. Radiographic examination showed a similar pattern of alveolar bone loss to that of the localized juvenile periodontitis. Suppressed monocyte and neutrophil chemotaxis were not detected. Slightly depressed CD2+, CD3+ and CD4+ and slightly elevated activity of NK cells were found. An elevated level of antibody to Porphyromonas gingivalis was observed and this antibody titer was decreased by periodontal treatments. The affected sites of the patient showed resistance to conventional periodontal therapy. P. gingivalis was estimated to associate as an important pathogen in the etiology of periodontal destruction in this hypophosphatasia patient in addition to the dental abnormalities such as abnormal enamel, dentin, or cementum formation.

Adolescent↗
PubMed1991

[Unilateral massive vesicoureteral reflux associated with congenital mechanical obstruction of lower urinary tract].

We reviewed 9 children with unilateral massive (III and IV, Dwoskin-Perlmutter) vesicoureteral reflux associated with congenital mechanical obstruction of the lower urinary tract. Four children with bilateral reflux with bilateral difference of severity more than 2 grades were also included. Obstruction was attributed to posterior urethral valve in 5, anterior urethral stricture in 3 and mega-urethra in 1. The chief complaints were febrile episodes and urinary infection, followed by voiding difficulty, bed wetting and/or urinary incontinence and voiding through anus. All 4 children with troubles other than posterior urethral valve had either anorectal anomaly or H-type rectourethral fistula without imperforate anus. Of the 9 children 8 had massive reflux on the left side. The majority of these left ureters with massive reflux were associated with ipsilateral severe renal hypofunction on scintigraphy. After prompt resolution of obstruction, the majority of these massive reflux did not disappear. Decompression appeared to salvage none of such kidneys. The orifice positions of such ureters were far cranio-lateral and the resected kidneys showed dysplasia or severe hypoplasia. The prognosis was generally excellent except one child with massive reflux on the right side who progressed to an end-stage renal disease. The embryogenesis of this "VURD syndrome" was discussed in its relation to the "bud theory" of renal hypo-dysplasia. It was showed that this syndrome was observable in obstructions other than the posterior urethral valve. Massive reflux appeared to serve as "pop-off" mechanism to buffer high pressure and to lead to preservation of better renal function. Reflux in children with congenital mechanical obstruction may be the result of 2 different mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1991

[The respiratory function in children with collagen disease].

Respiratory function tests were performed on 60 children with collagen disease. Twenty-seven cases (45%) showed abnormalities in the respiratory function. These abnormalities were restrictive in 14 cases (52%), obstructive in 6 cases (22%), and mixed type in 7 cases (26%). Eight out of 14 SLE patients (57%) showed abnormalities of various types. Abnormalities were seen in 9 out of 25 JRA patients (36%) including 6 cases (67%) with restrictive type changes. Four out of 6 MCTD (67%) and 3 out of 9 DM (33%) patient showed functional abnormalities. Most of patients with these two types of collagen disease showed restrictive changes. Investigations performed by a research group of the Ministry of Health and Welfare showed the incidence of restrictive type changes (% VC less than 80) in adult patients of collagen disease to be in the following descending order: PM/DM greater than PSS greater than MCTD greater than SLE. Though small in number, our investigation revealed that a considerable proportion of MCTD and SLE patients showed restrictive changes in respiratory function. In evaluating the clinical course of the disease, it was thus considered to be important to follow up the progress of respiratory functions in children with collagen disease.

Adolescent↗
PubMed1991

[Renal-sparing procedures in the management of renal arteriovenous fistula].

Five cases of renal arteriovenous fistula which were treated by renal-sparing procedures are reported. Transcatheter arterial embolization was performed in three cases of circoid type arteriovenous fistula. Gross hematuria stopped immediately after the treatment in these three cases. Another two patients, whose arteriovenous fistula were aneurysmal type, were treated by ligation of the feeding artery. Although there were no symptoms after the surgery, the follow-up renal arteriography revealed the residue of a small amount of arteriovenous fistula in one of the aneurysmal type cases. We suggest that the renal arteriovenous fistula be classified into circoid type and aneurysmal type in the diagnosis for the appropriate treatment of renal arteriovenous fistula. It is important to select the renal-sparing procedure according to the type of renal arteriovenous fistula.

Adult↗
PubMed1991

Immunoelectron microscopic observation of cells in the rat retinal containing gamma-aminobutyric acid and catecholamine.

Interactions between gamma-aminobutyric acid (GABA)- and catecholamine (CA)-containing cells in the rat retina was revealed by a double-labeling immunocytochemical technique using the antisera to GABA- and CA-synthesizing enzymes, such as tyrosine hydroxylase (TH) and phenylethanolamine-N-methyltransferase (PNMT). At the light microscopic level, GABA-, TH- and PMNT-immunoreactive (GABA-, TH- and PMNT-IR) amacrine cell bodies and their processes appeared in the inner nuclear layer and the inner plexiform layer, respectively. By electron microscopy observation, in the inner plexiform layer, GABA-, TH- or PMNT-IR amacrine cell processes were found making synaptic contacts with the axon terminals of immunonegative bipolar cells or with the processes of immunonegative amacrine cells. TH-IR amacrine cell processes formed synapse-like contacts with the GABA-IR amacrine cell perikarya and processes. In contrast, GABA-IR amacrine cell processes formed symmetric synaptic contacts onto the TH-IR as well as PNMT-IR amacrine cell processes. From these findings, it appears that the GABA- and CA-containing amacrine cells may interact with each other and play some important role in regulating the activities of bipolar cells and other unknown amacrine cells in the rat retina.

Animals↗