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Biomedical subjects

K Yamane

Publications and source records attributed to K Yamane.

At least 199 records · Page 11Linked to original sources
PubMed1993

Ankylosing spondylitis successfully treated with methotrexate.

A 37-year-old man with ankylosing spondylitis (AS) and psoriasis who was successfully treated with methotrexate (MTX) is reported. In 1980, he had low back pain, limited motion in the lumbar spine, radiological findings of bilateral sacroiliitis, and HLA-B27 positivity. In January 1991, he developed psoriasis and he had difficulty in performing desk work in spite of treatment with antirheumatic drugs. In May 1991, MTX 7.5 mg/week per os was started. Joint symptoms, psoriasis, and acute phase reactants improved within 1 month after the treatment and this improvement continued for more than 6 months after the treatment. After discharge he was able to return to his job.

Adult↗
PubMed1993

Hemodynamic study on flow patterns in the carotid bifurcation before and after carotid endarterectomy using cine magnetic resonance imaging.

Blood flow in the cervical carotid bifurcation was investigated by cine magnetic resonance imaging. In patients without stenosis, a low-intensity stream was demonstrated from the beginning of the carotid bulb, which was more distinct in the systolic phase. In patients with stenotic carotid bifurcations, the low-intensity flow was also present but was more prominent than in the non-stenotic bifurcation. This low-intensity stream may be due to the change from steady to turbulent flow due to the geometric characteristics of the carotid bifurcation or atheromatous plaque, similar to the flow separation phenomenon in fluid dynamics because of the coincidence of location and flow pattern. After carotid endarterectomy, turbulent flow was seen at the proximal and distal ends of the endarterectomy. Close follow-up and administration of antiplatelet agents are necessary to prevent restenosis due to mural thrombosis induced by such turbulent flow.

Carotid Arteries↗
PubMed1993

[A case of migraine with aura associated with meningioma].

We reported a case of migraine with aura associated with meningioma. A 66-year-old female visited to our department in 1985, with occipital throbbing pain following visual hallucination and nausea. She had been diagnosed as migraine. CT scan, magnetic resonance image and angiography showed a right occipital tumor, which was totally removed in 1990. Postoperatively, the migraine disappeared completely. The tumor was histologically diagnosed as fibroblastic meningioma. We supposed that the migraine had been associated with meningioma. Although some previous papers reported correlation with brain tumor and migraine, as example of arteriovenous malformation or angioma, migraine associated with meningioma is very rare. In arteriovenous malformation, pathophysiology of migraine is unclear, but induction of circulatory disturbance in the distribution of the posterior cerebral, posterior communicating and basilar artery is supposed. And then a space occupying lesion in the occipital lobe is possible to cause in the circulatory disturbance of the posterior cerebral and basilar artery. In the diagnosis of migraine, we should consider its relation to brain tumors, such as meningioma.

Aged↗
PubMed1993

[A case of cavernous angioma--usefulness of magnetic resonance imaging and magnetic resonance angiography in diagnosis].

We reported a case of cavernous angioma in the middle cranial fossa, which was diagnosed with magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). The patient was a 56-year-old female, who presented with sudden onset right-sided headache with nausea. Her neurological findings were normal. On CT scan a high density area with a surrounding thin low density area was shown in the right posterior temporal region without contrast enhancement. Cerebral angiography of the left vertebral artery revealed only a small stain at the end of the right posterior temporal artery. On T2-weighted MRI after one month, the same region exhibited a central area of mixed signal intensities surrounded by a rim of decreased signal. MRA showed an area with remarkable 10mm mass with some contiguous vessels in the right posterior temporal region. That mass was resected operatively. It's pathological diagnosis was cavernous angioma. For diagnose of cavernous angioma, MRI and MRA were very useful. The specificity of these methods are superior to better than CT or angiography.

Brain Neoplasms↗
PubMed1992

Ligand-induced functions of the epidermal growth factor receptor require the positively charged region asymmetrically distributed across plasma membrane.

Many plasma membrane proteins, including the epidermal growth factor (EGF) receptor, possess basic regions on the cytoplasmic surface of the membrane. To examine the function of these positively charged regions, we constructed mutated EGF receptor genes lacking this region by substitution of the basic amino acid residues with 3 approximately 8 neutral Asn residues, or by their complete deletion. There was no significant difference in the affinities for EGF of the wild-type and mutant receptors which are produced in rodent fibroblasts through transfection. However, EGF-induced tyrosine phosphorylation of the receptor was strongly inhibited by removal of the 3 approximately 8 positively charged residues. On addition of EGF, cells expressing the mutant EGF receptors did not show morphological changes, whereas cells expressing the wild-type receptor did. These findings suggest that the positively charged regions of membrane proteins that are asymmetrically distributed on the cytoplasmic surface of the membrane may be required for the functions of membrane proteins in general.

3T3 Cells↗
PubMed1992

Site-directed mutagenesis of active site residues in Bacillus subtilis alpha-amylase.

Site-directed mutagenesis of Bacillus subtilis N7 alpha-amylase has been performed to evaluate the roles of the active site residues in catalysis and to prepare an inactive catalytic-site mutant that can form a stable complex with natural substrates. Mutation of Asp-176, Glu-208, and Asp-269 to their amide forms resulted in over a 15,000-fold reduction of its specific activity, but all the mutants retained considerable substrate-binding abilities as estimated by gel electrophoresis in the presence of soluble starch. Conversion of His-180 to Asn resulted in a 20-fold reduction of kcat with a 5-fold increase in Km for a maltopentaose derivative. The relative affinities for acarbose vs. maltopentaose were also compared between the mutants and wild-type enzyme. The results are consistent with the roles previously proposed in Taka-amylase A and porcine pancreatic alpha-amylase based on their X-ray crystallographic analyses, although different pairs had been assigned as catalytic residues for each enzyme. Analysis of the residual activity of the catalytic-site mutants by gel electrophoresis has suggested that it derived from the wild-type enzyme contaminating the mutant preparations, which could be removed by use of an acarbose affinity column; thus, these mutants are completely devoid of activity. The affinity-purified mutant proteins should be useful for elucidating the complete picture of the interaction of this enzyme with starch.

Acarbose↗
PubMed1992

Functional relationships between cyclodextrin glucanotransferase from an alkalophilic Bacillus and alpha-amylases. Site-directed mutagenesis of the conserved two Asp and one Glu residues.

Comparison of the amino acid sequences of cyclodextrin glucanotransferases (CGTases) with those of alpha-amylases revealed that two Asp and one Glu residues, which are considered to be the catalytic residues in alpha-amylases, were also conserved in CGTases. To analyze the function of the three conserved amino acid residues in CGTases, site-directed mutagenesis was carried out. The three mutant CGTases, in which Asp229, Glu257 and Asp328 were individually replaced by Asn or Gln, completely lost both their starch-degrading and beta-cyclodextrin-forming activities, whereas another mutant CGTase, in which Glu264 was replaced by Gln, retained these activities. The three inactive enzymes retained the ability to be bound to starch. These results suggest that Asp229, Glu257 and Asp328 play an important role in the enzymatic reaction catalyzed by CGTase and that a similar catalytic mechanism is present in both CGTases and alpha-amylases.

Aspartic Acid↗
PubMed1992

Anti-interleukin-6 autoantibodies in rheumatic diseases. Increased frequency in the sera of patients with systemic sclerosis.

OBJECTIVE: To investigate the presence and the roles of anti-interleukin-6 (anti-IL-6) autoantibodies in rheumatic diseases, and to further elucidate clinical and pathophysiologic significance of anticytokine autoantibodies. METHODS: Anti-IL-6 IgG autoantibodies were measured by the 125I-IL-6 binding activity of IgG, which was isolated from serum by protein A-Sepharose. RESULTS: Nine of 52 sera (17.3%) from patients with systemic sclerosis (SSc) contained anti-IL-6 antibodies, whereas only 1.9% of sera from normal subjects and 0-5% of sera from patients with other rheumatic diseases were positive for the antibodies. Moreover, anti-IL-6 autoantibodies were found predominantly among patients with the limited form of SSc (42.9%), compared with those with the diffuse form (7.9%). CONCLUSION: Anti-IL-6 IgG autoantibodies were detected in patients with SSc, particularly those with the limited form of the disease, at a significantly increased frequency compared with normal subjects and patients with other rheumatic diseases. These results suggest that the development of anti-IL-6 autoantibodies and IL-6 may have a role in the pathophysiology of SSc.

Adult↗
PubMed1992

Sporadic amyotrophic lateral sclerosis with extensive neurological involvement.

We report an autopsy case of respirator-assisted long-survival sporadic amyotrophic lateral sclerosis (ALS) with extensive involvement extending beyond the motor system. The involved areas included the globus pallidus, subthalamic nucleus, red nucleus, substantia nigra, Clarke's column, intermediolateral nucleus, Onuf's (Onufrowicz) nucleus, middle root zone of the posterior column, and the spinocerebellar tract. There was no impairment of ocular movements. Such sporadic ALS cases with extensive involvement extending beyond the motor system may constitute a distinct subgroup of this disease that differs from long-survival ALS (with or without respirator support) in which only the motor system is affected.

Aged↗
PubMed1992

Arteriovenous malformation of the pancreas associated with hepatocellular carcinoma. A case report and review of the literature.

A case of pancreatic arteriovenous malformation (AVM) with hepatocellular carcinoma is reported. The patient, a 56-year-old Japanese man, was asymptomatic. The pancreatic lesion was found incidentally during an evaluation for hepatocellular carcinoma. Celiac arteriogram demonstrated tortuous feeding arteries, a racemose intrapancreatic stain, which disappeared before the venous phase, and early portal filling.

Arteriovenous Malformations↗
PubMed1992

A modified model of reversible middle cerebral artery embolization in rats without craniectomy.

A detailed description is given of a new model of reversible focal cerebral ischaemia in rats. A spherical embolus, attached to the end of an 8-0 surgical thread was injected into the middle cerebral artery (MCA) via the external and internal carotid arteries (ECA and ICA) and could be withdrawn by pulling the extravascular portion of the thread when reperfusion was to follow ischaemia. In contrast to similar techniques, the 8-0 thread did not block blood flow in either the common carotid artery (CCA) or the ICA during ischaemia and, as the CCA did not have to be ligated, flow could be restored via the ipsilateral CCA and ICA after the ischaemic period. Neurological deficit, mortality rate, tissue water content, regional pH, ATP and, in some experiments, electroencephalogram (EEG) and cerebral blood flow (CBF) were evaluated in ischaemia and after various length of reperfusion. The overall mortality rate was 21%; all these animals were lost in the first hours of recirculation. The water content of their brains differed significantly from those who survived 24 hours (81 and 77% respectively). A significant difference in CBF of the ipsi- and contralateral putamen was found immediately after embolization (a CBF decrease of 26 +/- 5 and 5 +/- 5 ml/100 g/min, respectively), and relative hyperperfusion (+23 +/- 27 ml/100 g/min) was observed in the ipsilateral putamen during reperfusion. EEG amplitude declined on both the affected and non-affected sides after embolization (to 54 +/- 8% and 71 +/- 6% of pre-ischaemic values) and remained decreased (66 +/- 8% of control) on the ipsilateral side after 1 hour of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

In vivo and in vitro characterization of the secA gene product of Bacillus subtilis.

The putative amino acid sequence from the wild-type Bacillus subtilis div+ gene, which complements the temperature-sensitive div-341 mutation, shares a 50% identity with the sequence from Escherichia coli secA (Y. Sadaie, H. Takamatsu, K. Nakamura, and K. Yamane, Gene 98:101-105, 1991). The B. subtilis div-341 mutant accumulated the precursor proteins of alpha-amylase and beta-lactamase at 45 degrees C as in the case of sec mutants of E. coli. The div-341 mutation is a transition mutation causing an amino acid replacement from Pro to Leu at residue 431 of the putative amino acid sequence. The B. subtilis div+ gene was overexpressed in E. coli under the control of the tac promoter, and its product was purified to homogeneity. The Div protein consists of a homodimer of 94-kDa subunits which possesses ATPase activity, and the first 7 amino acids of the putative Div protein were found to be subjected to limited proteolysis in the purified protein. The antiserum against B. subtilis Div weakly cross-reacted with E. coli SecA. On the other hand, B. subtilis Div could not replace E. coli SecA in an E. coli in vitro protein translocation system. The temperature-sensitive growth of the E. coli secA mutant could not be restored by the introduction of B. subtilis div+, which is expressed under the control of the spac-1 promoter, and vice versa. The B. subtilis div+ gene is the B. subtilis counterpart of E. coli secA, and we propose that the div+ gene be referred to as B. subtilis secA, although Div did not function in the protein translocation system of E. coli.

Adenosine Triphosphatases↗
PubMed1992

Small cytoplasmic RNA of Bacillus subtilis: functional relationship with human signal recognition particle 7S RNA and Escherichia coli 4.5S RNA.

Small cytoplasmic RNA (scRNA; 271 nucleotides) is an abundant and stable RNA of the gram-positive bacterium Bacillus subtilis. To investigate the function of scRNA in B. subtilis cells, we developed a strain that is dependent on isopropyl-beta-D-thiogalactopyranoside for scRNA synthesis by fusing the chromosomal scr locus with the spac-1 promoter by homologous recombination. Depletion of the inducer leads to a loss of scRNA synthesis, defects in protein synthesis and production of alpha-amylase and beta-lactamase, and eventual cell death. The loss of the scRNA gene in B. subtilis can be complemented by the introduction of human signal recognition particle 7S RNA, which is considered to be involved in protein transport, or Escherichia coli 4.5S RNA. These results provide further evidence for a functional relationship between B. subtilis scRNA, human signal recognition particle 7S RNA, and E. coli 4.5S RNA.

Bacterial Proteins↗
PubMed1992

Maturation of an NH2-terminally extended thermostable alpha-amylase in Bacillus subtilis: a possible mechanism examined by in vitro experiments.

An artificially inserted extra peptide (21 amino acid peptide) between the B. subtilis alpha-amylase signal peptide and the mature thermostable alpha-amylase was completely cleaved by B. subtilis alkaline protease in vitro. The cleavage to form a mature enzyme was observed between pH 7.5 and 10, but not between pH 6.0 and 6.5, although a similar protease activity toward Azocall was observed between pH 6.0 and 7.5. To analyze the effects of pH on the cleavage, CD spectra at pH 6, 8, and 11 of the NH2-terminally extended thermostable alpha-amylase were analyzed and the results were compared with those of the mature form of the alpha-amylase. It is suggested that the cleavage of the NH2-terminally extended peptide is controlled by the secondary and tertiary structure of the precursor enzyme. Similar cleavage of different NH2-terminally extended peptides by the alkaline protease was also found in other hybrid thermostable alpha-amylases obtained.

Amino Acid Sequence↗
PubMed1992

Abnormalities of pulmonary function in patients with non-insulin-dependent diabetes mellitus.

To examine the possible association between the vascular complications of diabetes and changes in pulmonary function, we performed pulmonary function tests including assessment of the diffusing capacity (%DLco) in 80 patients with non-insulin-dependent diabetes mellitus (45 males and 35 females) without overt lung or heart disease. The mean age of the subjects was 57.9 years and the mean duration of diabetes was 10.8 years. The %DLco decreased significantly as the duration of diabetes increased (r = -0.38, p less than 0.01), and the same relationship was also observed in non-smoking subjects (N = 37). The reduction in %DLco was greater in patients with diabetic microangiopathy (especially nephropathy) and in those treated with insulin. Other pulmonary function tests (%VC, FEV1.0, PaO2 and PaCO2) showed no relationship to the duration of diabetes, the degree of microangiopathy or the type of treatment. These results suggest that diabetic microangiopathy may play an important role in the decrease of %DLco.

Aged↗
PubMed1992

Progressive systemic sclerosis complicated with immune thrombocytopenia during D-penicillamine therapy.

Immune thrombocytopenia is a rare complication of progressive systemic sclerosis (PSS). A 47-year-old female with PSS treated with D-penicillamine developed immune thrombocytopenia, which promptly responded to prednisolone and withdrawal of D-penicillamine. Platelet-associated IgG was elevated and the bone marrow megakaryocyte count was normal. There was an inverse relationship between the level of platelet-associated IgG and the platelet count. A lymphocyte stimulation test sensitized by D-penicillamine was positive. The present case suggests that immune thrombocytopenia may be regarded as one of the D-penicillamine-related immune abnormalities. To our knowledge, its association with PSS has never been reported.

Blood Platelets↗