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Biomedical subjects

M Cho

Publications and source records attributed to M Cho.

126 records · Page 7Linked to original sources
PubMed1988

Horizontal and vertical vergence training and its effect on vergences, fixation disparity curves, and prism adaptation: II. Vertical data.

The purpose of this study was to assess the effects of horizontal and vertical vergence training on vertical fusional amplitudes, the vertical fixation disparity (VFD) curve, and prism adaptation. Thirty-four subjects were divided into three groups. One-third served as controls and the other two-thirds underwent 5 h of supervised horizontal and vertical vergence training, respectively. We hypothesized that subjects in the vertical group would manifest increased vertical vergence amplitude and coefficients of adaptation in concert with flatter VFD slopes. Before and after the 4-week training period, vertical vergences, fixation disparity (FD) curves, and coefficients of vertical prism adaptation were measured by a single individual who was intentionally uninformed of each subject's group. Analysis of the data suggests that changes in the vertical fusional amplitudes increased slightly. Although changes in the VFD slope and coefficient of prism adaptation were not statistically significant, the changes were much greater in the vertical group and in the hypothesized direction. We suggest that the results offer preliminary support for our hypothesis.

Adaptation, Ocular↗
PubMed1988

[A clinical study of testicular tumors].

Thirty-one patients with testicular germ cell tumors were treated in our Department between January, 1979 and June, 1987. Of the 31 patients, 17 (54.8%) had seminoma and 14 (45.2%) had non-seminomatous germ cell tumor (NSGCT) histopathologically. Clinical stage of seminoma was stage I in 13 patients (76.5%) and stage II in 4 patients (23.5%). Clinical stage of NSGCT was stage I in 8 patients (57.2%), stage II in 1 patient (7.1%) and stage III in 5 patients (35.7%). The patients with stage II seminoma underwent high inguinal orchiectomy, radiation therapy, retroperitoneal lymphnode dissection (RPLND) and chemotherapy, and those with stage II and III NSGCT underwent high inguinal orchiectomy and chemotherapy. All patients with stage II seminoma are alive with no evidence of disease. Three patients with stage II and III NSGCT are alive with no evidence of disease, but 3 patients died of the disease. Survival of patients with stage I and II seminoma at 5 years was 100% Survival of stage I and II NSGCT and III NSGCT at 5 years was 100% and 40%, respectively. According to our experience, for patients with advanced seminoma, combination chemotherapy and RPLND as well as radiation therapy are effective. In addition, for patients with advanced NSCGT, adjuvant chemotherapy followed by RPLND is effective.

Adolescent↗
PubMed1987

Differences in the activation rates of plasminogen by tissue plasminogen activator and urokinase.

The activation of a native form of plasminogen (Glu-plg) by tissue plasminogen activator(t-PA) was enhanced when the plasma was clotted by the addition of thrombin or thrombin plus Ca++. Cross-linking of fibrin in the clotted plasma did not inhibit the fibrin-associated enhancement of the activation of plasminogen by t-PA. When fibrinolysis induced by t-PA in the clotted plasma was measured using enzyme immunoassay, lysis of non cross-linked fibrin in the clotted plasma was faster than lysis of cross-linked fibrin, however such decrease in the extent of fibrinolysis was observed in cross-linked fibrin even in the absence of alpha 2antiplasmin (alpha 2AP) in a purified system. When Glu- or Lys-plg (modified plg) was activated by t-PA, the presence of fibrin enhanced significantly the extent of activation of both Glu- and Lys-plg, but the activation of Glu-plg by urokinase (UK) was enhanced in the presence of fibrin. The activation of Lys-plg by UK was rather inhibited in the presence of fibrin.

Enzyme Activation↗
PubMed1981

Sequential events in the formation of collagen secretion granules with special reference to the development of segment-long-spacing-like aggregates.

The formation and maturation of collagen secretion granules in periodontal ligament (PDL) fibroblasts of young male Balb-C mice were studied by electron microscopy and cytochemistry. The Golgi apparatus was composed of several dictyosomes, each consisting of a stack of five smooth-walled cisternae. Each cisterna was connected at both ends to a dilated saccule. The cisternae, with their associated pairs of saccules, underwent progressive maturational changes from the immature to mature face of each dictyosome. The most immature saccules (type 1) were large, spherical, and filled with loosely arranged short filamentous structures. These saccules were continuous with the first and second Golgi cisternae (counting from the immature side). Golgi saccules type 2 were ellipsoidal, associated with the third and fourth cisternae, and contained parallel, elongate filaments. The most mature saccules, type 3, were more rectangular and connected by a short fifth cisterna. They contained aggregated filamentous material in the form of eight segment-long-spacing (SLS)-like crystallites, one in the center and seven at the periphery, to form a basic secretory unit. As type 3 saccules matured, the interconnecting cisterna progressively shortened until the two saccules were nearly juxtaposed. At this time the shortened fifth cisterna split to give rise to two independent presecretory granules. By progressive condensation, presecretory granules matured into secretion granules that contained a densely packed SLS-like aggregate, within which individual crystallites were no longer discernable. Maturation of cisternae and saccules involved removal of membrane, apparently by the formation and detachment of coated vesicles. The staining reaction with silver methenamine and phosphotungstic acid increased over the procollagen as the saccules matured, indicating addition of carbohydrate moieties and possible crosslinkages. It is concluded that the formation and maturation of collagen secretion granules in PDL fibroblasts involves the packaging and further modification of eight SLS-like crystallites, which are secreted as a basic unit.

Animals↗
PubMedDate not supplied

Isolation and characterization of a cDNA clone encoding the murine homologue of the human 20K T3/T-cell receptor glycoprotein.

The antigen receptor on the surface of human T lymphocytes, which consists of a heterodimer of relative molecular mass (Mr) 90,000 (90K) (alpha- and beta-chains), is associated with the T3 antigen (gamma = 25K, delta = 20K and epsilon = 20K). A working model for the mode of action of the T3/T-cell receptor complex is that the clonotypic alpha- and beta-chains are involved in the recognition and binding of antigen in the context of polymorphic major histocompatibility complex (MHC) gene products on the surface of target cells. Antigen binding by the clonotypic receptor probably results in conformational changes in this structure which are recognized by and subsequently trigger the associated T3 complex to transmit signals into the cell, resulting in a proliferative response. The similarity in structure between murine and human clonotypic antigen receptors suggests that such a mechanism of recognition and activation also exists in mouse T lymphocytes, but so far there has been no evidence for the existence of a murine T3 complex. Here we demonstrate the existence of a T3 delta-chain mRNA in murine T lymphocytes. Our sequence data strongly suggest that this mouse mRNA codes for a complete T3 delta polypeptide chain and reveal some interesting properties of the protein.

Amino Acid Sequence↗
PubMedDate not supplied

Isolation of cDNA clones encoding the 20K non-glycosylated polypeptide chain of the human T-cell receptor/T3 complex.

The antigen receptor on human T lymphocytes consists of two variable immunoglobulin-like glycoproteins, alpha and beta, which occur in association with three invariable T3 membrane proteins. In humans two of these proteins, T3-gamma and T3-delta, are glycoproteins of relative molecular mass (Mr) 25,000 (25K) and 20,000 (20K), respectively, while the third, T3-epsilon, is a 20K non-glycosylated protein. On the surface of murine T cells, a non-glycosylated protein dimer composed of 17K subunits (T3-zeta) is found associated with the T-cell receptor alpha and beta chains and the three T3-like polypeptide chains. It is generally accepted that major histocompatibility complex-restricted antigen recognition is a function of the alpha-beta heterodimer. This has led to the postulation that the proteins of the T3 complex are involved in the signal transduction that immediately follows antigen recognition via the antigen receptor. Events believed to be involved in early T-cell activation, such as rapid increases in phosphatidylinositol turnover and free intracellular calcium, can be triggered by antibodies directed against either the T3 complex or the clonotypic receptor. We have previously reported our findings on the cloning of the complementary DNA and genomic structure encoding both the human and murine 20K glycoprotein, T3-delta (refs 11-13). We now present our results on the cloning of the cDNA encoding the human 20K non-glycosylated chain, T3-epsilon.

Amino Acid Sequence↗
PubMedDate not supplied

Prognostic value of nm23 protein expression in renal cell carcinomas.

In the present study, an analysis of whether expression of nm23-H1 and nm23-H2 proteins has prognostic significance was performed. A series of 95 renal cell carcinomas was analyzed for nuclear grade, tumor size (larger than 50 mm or not), staging in the Robson system and expression of nm23-H1 and nm23-H2, as well as patient survival. Immunohistochemical staining of nm23-H1 and nm23-H2 was found in 68.4 and 50.5% of the cases, respectively. Significant differences in nm23-H1, but not nm23-H2 expression were noted with regard to nuclear grade and tumor size. The patients with nm23-H1-expression-negative tumors sized < or = 50 mm had a significantly poorer prognosis than their positive counterparts. Multivariate analysis using the Cox proportional hazards regression model indicated that the staging in the Robson system and expression of nm23-H1 were significant and independent prognostic factors for survival. However, no significant correlation between the incidence of metastasis and expression of nm23-H1 or nm23-H2 was found. The results imply that reduced expression of nm23-H1 influences the prognosis of patients with renal cell carcinomas, but not the likelihood of metastasis. In small tumors sized < or = 50 mm, reduced expression of nm23-H1 protein was suggested to be an especially strong predictor of a poor prognosis.

Adult↗
PubMedDate not supplied

Effect of hexachloro-1,3-butadiene on renal carcinogenesis in male rats pretreated with N-ethyl-N-hydroxyethylnitrosamine.

Hexachloro-1,3-butadiene (HCBD) is a potent nephrotoxicant that selectively damages the straight portion (pars recta) of the proximal tubule in the rat. To determine its effects on carcinogenesis. HCBD was administered for 30 wk at a concentration of 0.1% by weight in basal diet to male Wistar rats previously given 0.1% N-ethyl-N-hydroxyethylnitrosamine (EHEN) in the drinking water for 2 wk. The combined treatment resulted in a significantly higher incidence of renal cell tumors than when EHEN was administered alone. This chronic exposure and a short course of a 0.2% HCBD diet for 3 wk caused marked increase in the numbers of bromodeoxyuridine-incorporating cells or proliferating cell nuclear antigen-positive cells in the outer stripe of the kidney. The ability of HCBD to promote EHEN-initiated renal tumorigenesis in rats thus appears to be associated intimately with linked nephropathy and subsequent cell proliferation.

Adenoma↗
PubMedDate not supplied

[Improving the quality of reports on randomized controlled trials. Recommendations of the CONSORT Study Group].

This summary corresponds to the translation into Spanish of the Special Communication published in the Journal of the American Medical Association in August 1996, along with the editorial published in the same issue "How to report Randomized Controlled Trials. The Consort Statement". It describes the Consolidated Standards for Preparation of Controlled Clinical Trials, prepared by a work group made up of members of the SORT Group and of the Asilomar Work Group, along with the director of a magazine and the author of the report on a clinical trial. The work was carried out by means of a Delphi process and the result was a check list and a process diagram. The check list is made up of 21 items that mainly refer to methods, results and discussions on the report of a controlled clinical trial, identifying the necessary information in order to be able to evaluate the internal and external value of the report, judging the improvement to be positive for the patient, the editors and the reviewers of the magazines.

Delphi Technique↗