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Biomedical subjects

K Yamane

Publications and source records attributed to K Yamane.

372 records · Page 21Linked to original sources
PubMedDate not supplied

Crystal structure of asparagine 233-replaced cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011 determined at 1.9 A resolution.

The crystal structure of asparagine 233-replaced cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011 was determined at 1.9 A resolution. While the wild-type CGTase from the same bacterium produces a mixture of mainly alpha-, beta- and gamma-cyclodextrins, catalyzing the conversion of starch into cyclic or linear alpha-1,4-linked glucopyranosyl chains, site-directed mutation of histidine-233 to asparagine changed the nature of the enzyme such that it no longer produced alpha-cyclodextrin. This is a promising step towards an industrial requirement, i.e. unification of the products from the enzyme. Two independent molecules were found in an asymmetric unit, related by pseudo two-fold symmetry. The backbone structure of the mutant enzyme was very similar to that of the wild-type CGTase except that the position of the side chain of residue 233 was such that it is not likely to participate in the catalytic function. The active site cleft was filled with several water molecules, forming a hydrogen bond network with various polar side chains of the enzyme, but not with asparagine-233. The differences in hydrogen bonds in the neighborhood of asparagine-233, maintaining the architecture of the active site cleft, seem to be responsible for the change in molecular recognition of both substrate and product of the mutant CGTase.

Amino Acid Substitution↗
PubMedDate not supplied

Subretinal neovascularization associated with retinochoroidal coloboma.

PURPOSE: To report a case of subretinal neovascularization associated with retinochoroidal coloboma. METHODS AND RESULTS: A 44-year-old female presented with metamorphopsia in her right eye for 4 weeks. Funduscopic examination revealed bilateral inferior retinochoroidal coloboma. Fluorescein angiography disclosed foci of subretinal neovascularization at the margin between the colobomatous defect and the normal-appearing retina. Five month later, multiple small areas of subretinal hemorrhages were noted. The hemorrhage was gradually absorbed. Six years after initial presentation, subretinal hemorrhage did not recur and her right VA was 0.2. CONCLUSIONS: Ophthalmologists should be aware of this rare but important complication of retinochoroidal coloboma.

Adult↗
PubMedDate not supplied

Ischemic heart disease in systemic lupus erythematosus. A retrospective study of 65 patients treated with prednisolone.

We studied the frequency of ST-T changes and ischemic heart disease (IHD) in prednisolone (PSL)-treated systemic lupus erythematosus (SLE) patients and compared them with the age-matched control of rheumatoid arthritis patients not receiving PSL. Twenty-five (38%) of the 65 SLE patients revealed ST-T changes as ST elevation (4%), ST depression (36%) and T wave flattening or inversion (60%). Among the control patients 4 (10%) had T wave flattening or inversion. The frequencies of ST-T changes in patients receiving total PSL dose of up to 5g and greater than 5g were 23% and 48%, respectively. Four patients developed IHD at an unusually young age during remission of SLE while receiving low dose of PSL and 2 of them later died of myocardial infarction (MI). The latter 2 patients had received PSL pulse therapy prior to MI. Regular ECG check up for SLE patients while they are on low dose PSL or pulse therapy may help reveal early ECG abnormalities and thus detect and treat one of the major risks of long-term effects of corticosteroid therapy.

Adolescent↗
PubMedDate not supplied

Serum levels of tissue inhibitor of metalloproteinases in patients with mixed connective tissue disease.

OBJECTIVE: To determine serum tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 levels in patients with mixed connective tissue disease (MCTD) and investigate whether these levels were correlated with the clinical or serological features of this disease. METHODS: Serum TIMP-1 and TIMP-2 levels were measured with specific enzyme-linked immunosorbent assays. Serum samples from 26 patients with MCTD and 18 healthy individuals were examined. RESULTS; Serum levels of TIMP-1 were significantly higher in patients with MCTD than those in healthy individuals (mean +/- SD: 218.9 +/- 50.8 ng/ml versus 160.0 +/- 38.7 ng/ml, P < 0.0001). MCTD patients with elevated TIMP-1 had esophageal involvement at a significantly higher incidence than those without (77.8% versus 35.3%, p < 0.05). There was no difference in serum TIMP-2 levels between patients with MCTD and healthy controls (75.6 - 11.9 ng/ml versus 77.3 +/- 10.7 ng/ml). CONCLUSION: These results suggest that TIMP-1 is involved in the pathogenesis of MCTD, and that TIMP-1 may be a serological marker for the presence of esophageal involvement in these patients.

Adult↗
PubMedDate not supplied

Clinical features of patients with systemic sclerosis accompanied by rheumatoid arthritis.

OBJECTIVE: To determine the incidence of patients with both systemic sclerosis and rheumatoid arthritis (SSc-RA) and the clinical features of those with SSc-RA. METHODS: All 173 patients with systemic sclerosis in our clinic were investigated. RESULTS: Of the 173 patients with systemic sclerosis, 9 (5.2%) developed rheumatoid arthritis (RA). At the first visit, arthritis prior to Raynaud's phenomenon, increased C-reactive protein (CRP), and elevated rheumatoid factor (RF) were seen in patients with SSc-RA at a significantly higher incidence than in those without (44.4% versus 4.8%, p < 0.01; 55.6% versus 13.6%, p < 0.001; 247.2 +/- 312.1 versus 47.9 +/- 54.3 IU/ml, p < 0.001, respectively). Furthermore, in 8 of the 9 patients with SSc-RA, CRP was increased before the diagnosis of RA. CONCLUSION: These results suggest that systemic sclerosis patients with elevated RF and a history of arthralgia prior to Raynaud's phenomenon should be followed up with serial measurements of CRP due to their risk of developing RA.

Adolescent↗