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Biomedical subjects

T Baba

Publications and source records attributed to T Baba.

At least 19 recordsLinked to original sources
PubMed1995

Classic steroid 11 beta-hydroxylase deficiency caused by a C-->G transversion in exon 7 of CYP11B1.

Steroid 11 beta-hydroxylase deficiency (11 beta OHD) is derived from mutations in the P45011 beta gene (CYP11B1) and inherited in an autosomal recessive manner. In the present study, we have performed a molecular genetic analysis of CYP11B1 in a Japanese patient clinically diagnosed as classic 11 beta OHD. Nucleotide sequencing of the PCR-amplified exons from the patient's genomic DNA reveals a unique C-->G transversion that converts codon 384 CGA (arginine) to GGA (glycine) in exon 7. Restriction fragment length polymorphism (RFLP) data demonstrate that the patient is homozygous for this mutation. When the full-length cDNA corresponding to CYP11B1 of the patient is transfected into COS-7 cells, no steroid 11 beta-hydroxylase activity is detectable in mitochondria of the cells. These results indicate that this point mutation completely abolishes P45011 beta activity and causes the classic 11 beta OHD.

Adolescent↗
PubMed1995

Developmental studies of dystrophin and other cytoskeletal proteins in cultured muscle cells.

We studied the developmental changes of localization of dystrophin and other cytoskeletal proteins, especially actin, spectrin and dystrophin related protein (DRP) using immunocytochemistry and quick-freezing and deep-etching (QF-DE) method. In developmental studies of mouse and human muscle cultures, some myoblasts had positive-reactions to spectrin, DRP, and F-actin, but not dystrophin. In aneurally cultured myotubes, dystrophin, DRP, and spectrin were localized diffusely in the cytoplasm and later in discontinuous patterns on the plasma membrane, when myotubes became mature. Spectrin and DRP had more positive reactions in immature myotubes, compared with those of dystrophin. In some areas of myotubes, dystrophin/spectrin and spectrin/actin were localized reciprocally. In innervated cultured human muscle cells, dystrophin and DRP were localized in neuro-muscular junctions, which were co-localized with clusters of acetylcholine receptors. By using the QF-DE method, dystrophin was localized just underneath the plasma membrane, and closely linked to actin-like filaments (8-10 nm in diameter), most of which were decorated with myosin subfragment 1. In actin-poor regions, spectrin was detected as well-organized filamentous structures in highly interconnected networks with various diameters. DRP was distributed irregularly with granular appearance inside the cytoplasm and also under the plasma membrane in immature mouse myotubes. Our present studies show that dystrophin, spectrin, and DRP are localized differently at the developmental stages of myotubes. These results suggest that dystrophin, spectrin, and DRP are organized independently in developing myotubes and these cytoskeletal proteins might play different functions in the preservation of plasma membrane stability in developing myotubes.

Adult↗
PubMed1995

Amino acid sequences of porcine Sp38 and proacrosin required for binding to the zona pellucida.

We previously purified a boar sperm protein, sp38, and demonstrated that this protein bound to the 90-kDa family of zona pellucida (ZP) glycoprotein in a calcium-dependent manner. Sp38 competed with proacrosin for the binding to the zona pellucida. Herein we have isolated cDNA clones encoding sp38 from a boar testis cDNA library in lambda gt11. The amino acid sequence deduced from the cDNA sequence indicated that sp38 is initially synthesized as a 350-residue precursor protein. The N-terminal 51-residue sequence preceded the N-terminus of the mature sp38. Thus, the sp38 precursor is post-translationally modified to produce the mature protein of 299 residues. Immunostaining of sperm cells using an antibody prepared against a fusion protein of sp38 with T7 gene 10 protein suggested that sp38 is localized at the intraacrosomal region and is released after the acrosome reaction. The 11-residue sequence, KRLSKAKNLIE, in sp38 shared a significant degree of similarity with the 8-residue sequence, KRLQQLIE, in the C-terminal region of porcine proacrosin. Both synthetic oligopeptides corresponding to these two sequences inhibited the binding of 125I-labeled sp38 to zona pellucida glycoprotein.

Acrosin↗
PubMed1995

Cranial fasciitis with massive intracranial extension.

The case of a 10-month-old boy with cranial fasciitis is described. The patient had a rapidly growing subcutaneous mass in the left frontotemporal region. Computed tomography and magnetic resonance imaging clearly demonstrated a mass in the left temporoparietal bone extending both intra- and extracranially. The tumor seemed to originate from the calvarium, being located between the periosteum and the dura mater. Total resection of the tumor was performed, and the tumor was histologically identified as cranial fasciitis. A brief review of the literature is included that emphasizes the need for further investigation of this benign lesion that is frequently confused with a malignant neoplasm.

Brain Diseases↗
PubMed1995

Clathrin-independent pinocytosis is induced in cells overexpressing a temperature-sensitive mutant of dynamin.

A stable HeLa cell line expressing a dynamin mutant, dynts, exhibits a temperature-sensitive defect in endocytic clathrin-coated vesicle formation. Dynts carries a point mutation, G273D, corresponding to the Drosophila shibirets1 allele. The ts-defect in receptor-mediated endocytosis shows a rapid onset (< 5 min) and is readily reversible. At the nonpermissive temperature (38 degrees C) HRP uptake is only partially inhibited. Moreover, when cells are held at the nonpermissive temperature, fluid phase uptake fully recovers to wild-type levels within 30 min, while receptor-mediated endocytosis remains inhibited. The residual HRP uptake early after shift to the nonpermissive temperature and the induced HRP uptake that occurs after recovery are insensitive to cytosol acidification under conditions that potently inhibit receptor-mediated endocytosis of Tfn. Together, these results suggest that a dynamin- and clathrin-independent mechanism contributes to the total constitutive pinocytosis in HeLa cells and that dynts cells rapidly and completely compensate for the loss of clathrin-dependent endocytosis by inducing an alternate endocytic pathway.

Clathrin↗
PubMed1995

Structure, organization, and chromosomal location of the gene encoding a form of rice soluble starch synthase.

A rice (Oryza sativa L.) genomic clone encoding the gene for a form of soluble starch synthase (SSS1) and its 5'- and 3'-flanking regions has been isolated and sequenced. The SSS1 gene contained 15 exons interrupted by 14 introns. The exon/intron organization of the SSS1 gene was divergent from that of the rice Waxy gene coding for granule-bound starch synthase, thus suggesting that the SSS1 and granule-bound starch synthase genes have evolved from an ancestral gene in a different way or that the two genes are products of different ancestral genes that have converged during evolution. However, these two genes were closely located to each other on rice chromosome 6 at an approximate map distance of 5 centimorgans. The nucleotide sequence of the 5'-end region of the gene is unique because of the presence of some repetitive sequences.

Alternative Splicing↗
PubMed1995

Successful treatment of dark-colored epidermal nevus with ruby laser.

The pulsed ruby laser has a selective thermolytic effect. Recently, it has been available for the treatment of superficial pigmented disorders. We studied 5 cases of epidermal nevus treated with the pulsed ruby laser. In comparison with the usual methods including electrocautery, cryotherapy and skin abrasion, ruby laser therapy is an excellent tool due to technological ease and rapid improvement. Depigmentation after treatment in 2 cases was the only side effect of this therapy. Bose cases had a dark pigmentation of the skin. Despite of the risk of discoloration, the ruby laser is one of the most effective tools for therapy of pigmented epidermal nevus.

Adolescent↗
PubMed1995

Disulfide bond formation and secretion of Escherichia coli heat-stable enterotoxin II.

The Escherichia coli heat-stable enterotoxin II (STII) is a typical extracellular toxin consisting of 48 amino acid residues, of which 4 are cysteine. There are two disulfide bonds, one between Cys-10 and Cys-48 and one between Cys-21 and Cys-36. We examined the involvement of DsbA in the formation of the disulfide bonds of STII and the role of each in the secretion of STII. A dsbA mutant was transformed with a plasmid harboring the STII gene, and STII was not detected either in the cells or in the culture supernatant. Reducing the level of STII brought about the dsbA mutation restored by introducing the wild-type dsbA gene into the mutant strain. These results showed that DsbA is involved in forming the disulfide bonds of STII and that STII without these disulfide bonds is degraded during secretion. We substituted these four cysteine residues in vivo by oligonucleotide-directed site-specific mutagenesis. The amino acid sequence of the purified STII (C48S) and pulse-chase studies revealed that two intermolecular disulfide bonds must be formed to be efficiently secreted and that cleavage between amino acid residues 14 and 15 is probably the first step in the proteolytic degradation of STII.

Bacterial Toxins↗
PubMed1995

[Effect of fluvoxamine, a new antidepressant drug, on monoamine dynamics in the rat cerebral limbic system and its pharmacological characteristic].

The effect of fluvoxamine (FLU) on the amine dynamics in serotonergic, noradrenergic or dopaminergic nervous systems in the rat cerebral limbic system was investigated, with reference to the pharmacological characteristics of FLU. Following single oral administration of 30 and/or 60 mg/kg FLU, significant decreases in the 5-hydroxyindole-3-acetic acid (5-HIAA)/serotonin (5-HT) ratios in the amygdala and hippocampus and the 4-hydroxy-3-methoxyphenylglycol (MHPG)/norepinephrine (NE) ratio in the amygdala were produced. FLU at 15 mg/kg, p.o. also caused a significant increase in MHPG/NE ratio in the hippocampus. On the other hand, imipramine (IMI) at 30 mg/kg, p.o. induced significant decreases in 5-HIAA/5-HT ratio in the hippocampus, MHPG/NE ratios in the amygdala and hippocampus, and 3,4-dihydroxyphenylacetic acid (DOPAC)/dopamine (DA) ratios in the amygdala, hippocampus and septum. The 5-HIAA/5-HT ratios in the amygdala and hippocampus and the MHPG/NE ratio in the septum were significantly decreased after repeated oral administration of 30 mg/kg FLU twice daily for 14 days, but the MHPG/NE ratio in the amygdala was increased. In the septum, DOPAC/DA ratio was significantly decreased following repeated administration of IMI at 30 mg/kg, p.o. These findings suggest that FLU inhibits 5-HT turnover in the amygdala and hippocampus as a result of the interference with the neuronal re-uptake mechanism for 5-HT. Also, FLU has an effect on NE turnover in the cerebral limbic system, and the effect may appear in connection with a change in the interaction of nervous systems.

Administration, Oral↗
PubMed1995

Migration of a subduroperitoneal shunt catheter into the subdural space--case report.

An 82-year-old male with intractable bilateral chronic subdural hematomas was treated by emplacement of bilateral subduroperitoneal shunts on the left in 1990 and on the right in 1991. Chronic subdural hematoma recurred in 1992 due to an unusual migration of a shunt catheter into the subdural space. This migration was probably due to inadequate fixation of the shunt. Shunt replacement and fixation with an anchoring wing has resulted in no further complications for 2 years.

Aged↗
PubMed1994

Sustained left ventricular tachycardia terminated by dipyridamole: cyclic AMP-mediated triggered activity as a possible mechanism.

Sustained VT in two patients was terminated by intravenous administration of dipyridamole, an adenosine transport inhibitor. VT was induced by rapid atrial or ventricular pacing, isoproterenol, or dibutyryl cyclic AMP infusion, or exercise. VT also was aborted by adenosine triphosphate or acetylcholine injection, or by vagal stimulation. VT was terminated or prevented by verapamil or propranolol. In addition, arrhythmias were prevented by oral administration of dipyridamole. These results suggest that VT is due to cyclic AMP-mediated triggered activity and that inhibition by dipyridamole may be due to a reduction in the intracellular concentration of cyclic AMP.

Acetylcholine↗
PubMed1994

The link between insulin resistance and hypertension. Effects of antihypertensive and antihyperlipidaemic drugs on insulin sensitivity.

Insulin resistance is generally interpreted as the physiological state under which insulin causes a reduced glucose-lowering effect. Hyperinsulinaemia is considered to be a result of insulin resistance. Many recent studies have suggested that hyperinsulinaemia and/or insulin resistance is associated with an elevated blood pressure, whereas several other studies have found a modest or no association. Many factors (e.g. adiposity, age, ethnic difference) have been suggested to confound the insulin-blood pressure relationship. Insulin is thought to raise blood pressure by a few possible mechanisms (e.g. stimulating sympathetic nervous system activity, enhancing renal tubular sodium reabsorption). On the other hand, insulin has also been reported to possess a vasodilatory property. Neither an insulin infusion within a physiological range nor continuously sustained hyperinsulinaemia in patients with insulinoma are associated with elevated blood pressure. Therefore, the relationship between insulin and blood pressure is still under discussion. Among the antihypertensive drugs, angiotensin converting enzyme (ACE) inhibitors seem to have marginal effects of improving insulin sensitivity, but whether this effect would lead to a better prognosis for diabetic patients remains to be proven. Lipid lowering drugs appear to show no benefit in lowering blood glucose.

Animals↗
PubMed1994

Gene expression of erythropoietin in hepatocellular carcinoma.

A 68-year-old man with hepatocellular carcinoma complicated by erythrocytosis showed an increased plasma level of immunoreactive erythropoietin (EPO). Northern blot analysis and RT-PCR (reverse transcriptase and polymerase chain reaction) of EPO mRNA extracted from a surgical specimen indicated high expression of EPO mRNA in the tumor tissue. Histological and immunocytochemical examination showed that the tumor was a hepatocellular carcinoma with predominant immunostaining for EPO. The erythrocytosis improved and the high serum EPO level decreased after resection of the tumor. This is the first demonstration of EPO mRNA expression in hepatocellular carcinoma tissue by RT-PCR.

Aged↗
PubMed1994

[Effects of ileal perfusion of carbohydrates on upper GI motility and pancreatic exocrine secretion].

The aim of this study was to determine if upper gut function and pancreatic exocrine secretion are affected by the presence of unabsorbed carbohydrate in the distal ileum. In this investigation, starch or glucose was perfused into the canine ileum. This study showed that ileal perfusion of both starch and glucose delayed gastric emptying and prolonged small bowel transit time. Furthermore, glucose had greater effects on gastrointestinal transit time than starch. In contrast, amylase output was increased by ileal perfusion of starch, but was not affected by that of glucose. Our results suggest that the ileal regulation of gastrointestinal transit and amylase output could be mediated by different mechanisms.

Amylases↗
PubMed1993

Antigenic protein specific for C3H strain mouse is a mitochondrial stress-70 protein.

Cells derived from C3H strain mouse produce an antigenic protein (CSA) specific for this strain [Kusakabe, M., et al. (1988) J. Cell Biol. 107, 257-265]. To examine the molecular basis of CSA, cDNA cloning of the antigenic protein was carried out. The deduced amino acid sequence demonstrates that CSA is the same protein as peptide-binding protein 74 (PBP74), a novel member of the stress-70 family. However, comparison of the PBP74/CSA sequences between C3H/HeN and BALB/c strain mice reveals the substitution of two amino acids in the substrate-recognition domain of the stress-70 protein. Western blot analysis indicates that one out of these two residues, arginine at residue 578 in the PBP74/CSA sequence of C3H mouse, contributes to the immunogenicity of CSA. Moreover, the subcellular localization of PBP74/CSA in mitochondria is also demonstrated by immunohistochemical analysis using anti-CSA monoclonal antibody. Thus, it is interesting that a genetic marker sequence in mice is located on the gene encoding a mitochondrial stress-70 protein.

Amino Acid Sequence↗
PubMed1993

Identification, cDNA cloning, and gene expression of soluble starch synthase in rice (Oryza sativa L.) immature seeds.

Three forms of soluble starch synthase were resolved by anion-exchange chromatography of soluble extracts from immature rice (Oryza sativa L.) seeds, and each of these forms was further purified by affinity chromatograph. The 55-, 57-, and 57-kD proteins in the three preparations were identified as candidates for soluble starch synthase by western blot analysis using an antiserum against rice granule-bound starch synthase. It is interesting that the amino-terminal amino acid sequence was identical among the three proteins, except that the 55-kD protein lacked eight amino acids at the amino terminus. Thus, these three proteins are products of the same gene. The cDNA clones coding for this protein have been isolated from an immature rice seed library in lambda gt11 using synthetic oligonucleotides as probes. The deduced amino acid sequence of this protein contains a lysine-X-glycine-glycine consensus sequence for the ADP-glucose-binding site of starch and glycogen synthases. Therefore, we conclude that this protein corresponds to a form of soluble starch synthase in immature rice seeds. The precursor of the enzyme contains 626 amino acids, including a 113-residue transit peptide at the amino terminus. The mature form of soluble starch synthase shares a significant but low sequence identity with rice granule-bound starch synthase and Escherichia coli glycogen synthase. However, several regions, including the substrate-binding site, are highly conserved among these three enzymes. Blot hybridization analysis demonstrates that the gene encoding soluble starch synthase is a single-copy gene in the rice genome and is expressed in both leaves and immature seeds. These results suggest that soluble and granule-bound starch synthases play distinct roles in starch biosynthesis of plant.

Amino Acid Sequence↗