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Biomedical subjects

Y Kita

Publications and source records attributed to Y Kita.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Cross-task analysis of age differences in constructive activity].

The present study investigated age differences in constructive activity, using three different tasks: the Rey-Osterrieth Complex Figure, Block Design, and Benton's 3D Construction tests. Participants were 116 healthy adults, ages ranging from 25 to 74 years. Results of the ROCF test failed to show any age difference in test scores among the participants up to early 60's, task completion time among those up to early 50's, and strategy among all participants. However, results of the Block Design test showed age differences in test score, task completion time, and strategy among all participants. Results of the 3D Construction test failed to show any age difference in test score among the participants up to early 60's, task completion time among those up to early 50's, but showed age differences in strategy among all participants. These findings suggest that it is necessary to take into account task-specific age differences in constructive skills, when evaluating constructive disabilities.

Adult↗
PubMed2001

[A case of malignant melanoma occurring 63 years after evisceration].

BACKGROUND: We report a rare case of a 69-year-old woman with malignant melanoma of her right socket, who had undergone evisceration of her right globe for unknown reasons at the age of 6. CASE: A 69-year-old woman presented with the complaint of inability to keep the prosthesis in her socket. A large blackish brown mass was seen behind the eyelids, and biopsy of this tissue revealed a mixed type malignant melanoma. A right exenteration was performed and histopathologic examination demonstrated a large tumor mass anterior and adjacent to the remains of the eviscerated globe. CONCLUSION: During evisceration, uveal pigment may be incompletely removed from the globe, or may be inadvertently scattered in the orbit. This case may demonstrate the development of a malignant melanoma from the uvea of an eviscerated globe. We recommend that careful long-term follow-up be performed on patients who have undergone evisceration.

Aged↗
PubMed2001

Selective reduction and recovery of invariant Valpha24JalphaQ T cell receptor T cells in correlation with disease activity in patients with systemic lupus erythematosus.

OBJECTIVE: To study the regulatory role of CD4-CD8- double-negative (DN) invariant T cell receptor (TCR) Valpha24JalphaQ T cells, a human counterpart of murine NK 1 + T cells, in the autoimmune process of systemic lupus erythematosus (SLE). METHODS: We carried out a 2 step frequency analysis of DN Valpha24JalphaQ T cells in patients with SLE before and after prednisolone therapy; the frequency of DN Valpha24+ T cells was determined by 3 color FACS analysis and subsequently the frequency of Valpha24JalphaQ rearrangement among DN Valpha24+ T cells was determined by sequencing. RESULTS: DN Valpha24+ T cells were significantly increased in patients with active SLE compared to healthy subjects. In healthy subjects, invariant Valpha24JalphaQ TCR dominated in DN Valpha24+ T cells at a high frequency (93-100%). However, the invariant Valpha24JalphaQ TCR was not detected in DN Valpha24+ T cells from patients with active SLE, and instead 2 to 9 Jalpha genes other than the invariant JalphaQ were oligoclonally expanded in the patients. In inactive SLE induced by prednisolone therapy, the invariant Valpha24JalphaQ TCR could be detected in DN Valpha24+ T cells from all the patients and dominated in most of the patients. Further, oligoclonally expanded Valpha24+ clones other than the invariant JalphaQ gene in active disease states were significantly decreased by prednisolone therapy. CONCLUSION: The selective reduction of DN invariant Valpha24JalphaQ T cells is related to the disease progression of SLE, while DN TCR Valpha24 T cells other than Valpha24JalphaQ T cells constitute autoaggressive T cells in SLE.

Adult↗
PubMed2001

Three-dimensional reconstruction of microcalcification clusters from two mammographic views.

Classification of benign/malignant microcalcification clusters is a major diagnostic challenge for radiologists. Clinical studies have revealed that the shape of the cluster, and the spatial distribution of individual microcalcifications within it, are important indicators of its malignancy. However, mammographic images of clustered microcalcifications confound their three-dimensional (3-D) distribution with image projection and breast compression. This paper presents a novel model-based method for reconstructing microcalcification clusters in 3-D from two mammographic views (cranio-caudal and medio-lateral oblique--"shoulder to the opposite hip" or lateral-medio). We develop a 3-D breast representation and a parameterised breast compression model which constraints geometrically the possible 3-D positions of a calcification in a two-dimensional image. Corresponding calcifications in the two views are matched using an estimate of the calcification volume. Both the geometric constraint and the matching criterion are utilized in the final reconstruction step to build the 3-D reconstructed clusters. Validation experiments are described using 30 clusters to verify the individual steps of the model, and results consistent with known ground truth are obtained. Some of the approximations in the model and future work are discussed in the concluding section.

Algorithms↗
PubMed2001

[Estimated relative and absolute risk for cardiovascular disease according to alcohol consumption increase in Japanese general population].

To calculate the estimated relative and absolute risks for cardiovascular diseases according to alcohol consumption increase, we performed a cross-sectional study of men aged 40-79 years using the data from the National Survey of Circulatory Disorders 1990 in Japan. First, we investigated the association between alcohol intake and two types of biochemical variables: serum lipids and blood pressure, by using analysis of variance. Then, concerning the subjects aged 40-59 years, linear regression analyses between alcohol intake and these biochemical markers were done to calculate regression coefficients adjusted for confounding factors. Finally, we substituted these regression coefficients for previously reported regression coefficients in Cox proportional hazard models to calculate relative and absolute risks for coronary heart disease and stroke. Alcohol intake positively correlated to systolic and diastolic blood pressure (SBP and DBP) and high-density lipoprotein cholesterol (HDLC). However, there was no relation between alcohol intake and serum total cholesterol. Linear regression coefficients of SBP, DBP and HDLC were 2.25, 1.43, 2.70, respectively. We used two proportional hazard regression formulas of Japanese population: one for coronary disease (Circulation 89, 2533-39) and the other for stroke (NIPPON DATA80, a 14-year cohort study of randomly selected Japanese). The estimated relative risks of coronary heart disease and stroke were 0.89 and 1.06 for 1 "go" (23 g of ethanol) increment of alcohol intake. The results indicate that the mortality rates shift from 0.44 to 0.39 per 1,000 person-years for coronary heart disease and from 0.76 to 0.81 per 1,000 person-years for stroke in the representative Japanese population aged 40-59 years. The absolute risk of cardiovascular disease may be unchanged if we assume 23 g increment of ethanol intake in Japan because the risk reduction in coronary heart disease was nearly equal to the risk increment in stroke.

Adult↗
PubMed2000

Neuronal cell apoptosis by a receptor-binding domain peptide of ApoE4, not through low-density lipoprotein receptor-related protein.

Since an apolipoprotein E4 (ApoE4) peptide composed of the low-density lipoprotein (LDL) receptor-related protein (LRP)-binding domain [ApoE4(141-149)(2) or ApoE(141-155)(2)] exerts neurotoxicity in primary neurons and neuronal cell lines, it has been controversial whether these effects are mediated by LRP. Here, we examined whether ApoE4(141-149)(2)-induced toxicity is mediated by LRP in a neuronal cell system where ApoE4 toxicity is mediated by LRP: serum-deprived F11 neuronal cells. In these cells, where ApoE4 exerted toxicity by apoptosis in a manner sensitive to both caspase inhibitors and pertussis toxin (PTX), ApoE4(141-149)(2) also caused cell death by apoptosis but in a caspase-inhibitor-resistant, PTX-resistant manner. ApoE4(141-149)(2)-induced death was not inhibited by antisense oligonucleotides to LRP. Therefore, we conclude that ApoE4(141-149)(2) is able to exert neurotoxicity without involving LRP.

Amino Acid Sequence↗
PubMed2000

Total synthesis of the antitumor antibiotic (+/-)-fredericamycin A by a linear approach.

A linear approach to the total synthesis of racemic fredericamycin A (1) through the oxidative intramolecular [4 + 2] cycloaddition of a (phenylthio)acetylene-cobalt complex is described, which is applicable for the asymmetric total synthesis of naturally occuring 1. The highlight of this work is the aromatic Pummerer-type reaction with 1-ethoxyvinyl chloroacetate, which effects the introduction of the oxygen functional group to the internal B-ring of the highly functionalized, congested polyaromatic ABC-ring moiety.

Antibiotics, Antineoplastic↗
PubMed2000

Ambident effect of a p-sulfinyl group for the introduction of two carbon substituents to phenol rings: a convergent synthesis of diverse benzofuran neolignans.

A convergent synthesis of diversely substituted benzofuran neolignans (8) is described employing a single p-sulfinyl group on the phenols (3) as an ambident functional group for two types of carbon-carbon bond-forming reactions: (i) the direct synthesis of the dihydrobenzofuran skeletons through an aromatic Pummerer-type reaction and (ii) the ipso-substitution of the sulfur functional group by carbon substituents through a ligand exchange reaction.

Benzofurans↗
PubMed2000

Stabilizing effects of caprylate and acetyltryptophanate on heat-induced aggregation of bovine serum albumin.

Acetyltryptophanate (AT) and caprylate (Cap) have been used to stabilize serum albumin against heat treatment. However, the mechanism of stabilization by these additives has never been fully elucidated. Here we used thermal melting to determine the effects of these additives on the melting temperature of bovine serum albumin (BSA) and heat stress at 60 degrees C to follow degradation of the protein in the presence of varying concentrations of AT or Cap. Native polyacrylamide gel electrophoresis was used to examine degradation products generated by heat treatment. Both additives increased the melting temperature of BSA, resulting in an increase by 12 degrees C at 5 mM AT and 3 degrees C at 1 mM Cap. They also conferred stability to BSA against heat stress at 60 degrees C. Complete protection was observed at 5 mM AT and 1 mM Cap. Comparison of AT and Cap in their effects on melting temperature and heat stress-induced degradation showed that a greater protection occurs with Cap which has a weaker effect on melting temperature. Based on this observation it was concluded that the observed protection by AT may be explained by its effects on melting temperature while that of Cap should be ascribed to other mechanisms.

Animals↗
PubMed2000

An efficient synthesis of peri-hydroxy aromatic compounds via a strong-base-induced

An efficient synthesis of peri-hydroxy aromatic compounds has been accomplished via a strong-base-induced [4+2] cycloaddition of homophthalic anhydrides with alpha-sulfinyl-substituted derivatives of enolizable enones. The unsubstituted enones did not undergo an efficient [4+2] cycloaddition reaction with homophthalic anhydrides, presumably due to their enolization under the basic reaction conditions. The sulfinyl group not only promotes the cycloaddition reaction but also undergoes in situ elimination under the reaction conditions to afford the peri-hydroxy aromatic compounds in a single step. The application of this methodology for the synthesis of a key intermediate of antitumor antibiotic fredericamycin A is described. PM3 calculations of various 2-substituted cyclopentenones as well as the mechanism of the cycloaddition are also discussed.

Journal Article↗
PubMed2000

Convenient enzymatic resolution of alcohols using highly reactive, nonharmful acyl donors, 1-ethoxyvinyl esters

1-Ethoxyvinyl esters 3, a new type of acyl donors for enzymatic resolution of racemic alcohols, were disclosed to be superior to the contemporary major reagents, vinyl esters 1 and isopropenyl esters 2. Three features of 3 are noticeable: (1) 3 generates ethyl acetate as a single coproduct, which does not affect any enzymes, while acetaldehyde liberated from 1 deactivates some kinds of lipases. (2) The reactivity of 3 was not less than that of 1 and much higher than that of 2, and the optical purity of the products was as high as that of 1 and 2. Especially, it was generally observed that 3 showed higher reactivity than 1 for reactions using Candida rugosa lipases, one of the most commonly employed lipases, having liberal applicability to substrates but sensitive to acetaldehyde. Twelve examples of the kinetic resolution of racemic secondary alcohols (5 and 10) and one desymmetrization of meso-alcohol 7 were presented employing the acetate 3a or the octanoate 3b and four types of lipases. (3) A one-pot procedure for the preparation of 3 from the corresponding carboxylic acid and the subsequent enzymatic resolution of alcohols, which has not been reported using 1 or 2, was elucidated. The chemical and optical yields of the products by this procedure were similar to those obtained using isolated 3.

Journal Article↗
PubMed2000

Protection of bovine serum albumin from aggregation by Tween 80.

In an attempt to explain the mechanism of protein stabilization conferred by detergents, we investigated the effect of Tween 80 on aggregation of bovine serum albumin (BSA) using circular dichroism (CD) and native gel electrophoresis. CD thermal scans showed that BSA denatures at about 54 degrees C in 20 mM Tris, pH 7.2, forming soluble aggregates. Because of this aggregation, thermal unfolding of BSA under these conditions was only partially reversible, as indicated by reduced signal changes in the second scan. On the basis of this observation, BSA was thermally stressed by incubating at 50, 60, or 70 degrees C for 15 min and then analyzed by native gel electrophoresis. There was no change at 50 degrees C before and after heating, whereas at 60 degrees C the intensity of the original monomer and dimer bands decreased and that of aggregate bands increased, with much greater changes at 70 degrees C. Addition of Tween 80 before heating reduced aggregation and increased the monomer content. These effects of Tween 80 were greater as its concentration was increased from 0.001 to 1%. There was no correlation between the protective effects and the critical micelle concentration (CMC) of Tween 80. Addition of Tween 80 after 15 min incubation at 70 degrees C, or after 70 degrees C heating followed by cooling to room temperature, had no effect, demonstrating that Tween 80 must be present during the 70 degrees C heating step to be protective. Native gel electrophoresis run at 60 degrees C showed multiple aggregate bands and new bands migrating around the dimer and monomer positions, which may correspond to precursors of aggregates. Tween 80 reduced formation of these new bands and aggregates, further demonstrating that it must be present during heating. Finally, CD thermal scans showed that 0.1% Tween 80 only slightly increased the apparent melting temperature. The observed stabilization of BSA against heat treatment is, therefore, due to Tween 80 altering aggregation behavior rather than inducing significant stabilization of the native state.

Animals↗
PubMed2000

Resected early lung cancer with pulmonary aspergilloma.

Pulmonary aspergillosis and lung cancer rarely occur simultaneously. We report a 66-year-old man with a round shadow in the thin-wall cavity of the right upper lobe. Radiological findings and transbronchial biopsy revealed squamous cell carcinoma complicated by aspergilloma at the site. Right upper lobectomy suggested that early lung cancer arose from preexisting lung scars containing an aspergilloma.

Aged↗