PubMed Health⌕ Search

Biomedical subjects

L A Valenzuela

Publications and source records attributed to L A Valenzuela.

15 recordsLinked to original sources
PubMed2000

Influence of refraction on tonometric readings after photorefractive keratectomy and laser assisted in situ keratomileusis.

PURPOSE: To determine the decrease of Goldmann tonometry after photorefractive keratectomy (PRK) and laser assisted in situ keratomileusis (LASIK) according to refraction prior to surgery. METHODS: Prospective simultaneous comparative case series of 53 myopic eyes (53 patients) that underwent PRK and 50 (50 patients) that underwent LASIK using the Summit Excimed SVS plus (Summit Technology, Inc., Walthan, MA, U.S.A.). PRK and LASIK were subdivided by refractive error into two subgroups of more than or less than -5 diopters (D). Central tonometric readings were taken prior to surgery and 12 months after surgery. RESULTS: In LASIK and PRK subgroups of more than -5 D, 85.7% (24) and 69.6% (24), respectively, gave lower readings than those taken before surgery. In LASIK and PRK subgroups of less than -5 D, 77.3% (17) and 53.3% (16), respectively, gave lower readings. The difference between the two is significant (p < 0.001). Average tonometry falls by 2.8 mmHG in the LASIK subgroup of more than -5 D (p < 0.001) and by 2.8 mmHG in the LASIK subgroup of less than -5 D (p < 0.001) and by 1.7 mmHG in the PRK subgroup of more than -5 D (p < 0.010). In PRK subgroup of less than -5 D, the tonometric changes are not significant (p = 0.971). CONCLUSIONS: High previous refraction (in PRK) and technique used determines lower final tonometric readings, bringing about more frequent and significant decreases in LASIK than in PRK for errors of more than and less than -5 D.

Adolescent↗
PubMed1983

Monoclonal antibody (F5) to human prostate antigen.

Hybridoma culture F5 has been developed which secretes monoclonal antibody (McAb) directed to an epitope of a prostatic glycoprotein of Mr 34 kD (Prostate Antigen, PA). Tissue levels of PA have been evaluated using a competitive-binding enzyme-immunoassay based upon the inhibition of McAb binding activity to purified antigen. Results indicated the specific occurrence of high antigen concentrations in extracts prepared from prostatic tissues. The antigenicity of epitope F5 is resistant to tissue fixation and embedding protocols, and has been demonstrated upon immunoperoxidase staining procedures. Immunoperoxidase data strongly indicate that McAb F5 possesses a singular specificity towards prostatic epithelial cells. Other tissues, whether normal or cancerous, fail to express this determinant. Specimens examined included epithelial and nonepithelial tissues along with a panel of carcinomas and sarcomas. The antibody was able to detect tumor cells at extra-prostatic sites and represents a powerful probe for the detection and differential diagnosis of metastatic cancer of the prostate.

Animals↗
PubMed1983

Monoclonal antibodies (F36/22 and M7/105) to human breast carcinoma.

Cloned hybridoma cell lines were obtained from fusions of murine myeloma cells with lymphocytes of mice immunized against human breast cancer cells. Hybridomas F36/22 and M7/105 produced antibodies whose binding to breast cancer cells could not be inhibited by prior absorptions with fibroblasts, lymphoblastoid cells, or erythrocytes. Results from cell surface binding assays using a panel of tumor cell lines indicated that antibodies F36/22 and M7/105 recognized determinants expressed maximally on breast cancer cells. Antibody F36/22 reacted with normal mammary epithelial membranes and milk fat globule membranes, whereas antibody M7/105 produced no detectable binding to these specimens. Antigens carrying these epitopes each showed reactivity with concanavalin A lectin. The determinant corresponding to antibody F36/22 was detectable in histological sections of a subset of breast tumors obtained at surgery.

Adenocarcinoma↗
PubMed1983

Tissue distribution of an epithelial and tumor-associated antigen recognized by monoclonal antibody F36/22.

Murine monoclonal antibody F36/22 was derived by immunizing BALB/c mice with human breast cancer cells. This antibody reacts with an antigen located both on differentiated mammary ductal epithelia and on breast carcinomas, as examined by indirect immunoperoxidase techniques. Although the expression of this antigen correlated with estrogen receptor levels of breast tumors, antibody F36/22 did not directly react with estrophilin. In contrast to the expression of classical differentiation antigens, this antigen was found in a high percentage of poorly differentiated carcinomas of the breast. Staining intensities were similar for well- and poorly differentiated tumors; thus, antigen expression was not related to tumor grade. Intratumoral heterogeneity of antigen expression was observed in the majority of tumors. Since a subset (64 of 80) of the breast carcinomas examined have expressed the antigen, McAb 36/22 was of use for the immunological subclassification of tumors which were indistinguishable by conventional histopathological staining techniques. The antigen was also present on other adenocarcinomas (ovary, colon, stomach, pancreas, and prostate); however, these tumors usually exhibited reduced staining intensity compared with that observed in breast cancer. The normal counterpart tissues at these histotypes contained no detectable levels of the antigen, and increased expression of the antigen was associated with tumorigenesis at these sites. Tumors of mesenchymal origin and carcinomas other than adenocarcinomas exhibited undetectable levels of the antigen. Therefore, depending on the organ site, McAb F36/22 recognizes an epithelial and/or tumor-associated antigen.

Animals↗
PubMed1982

A simplified purification procedure for human prostate antigen.

Methods for purifying the human prostate specific antigen are described. The antigen was isolated from human prostate and seminal plasma. Purified antigen (ca. 1 mg/ml) from seminal plasma was immunologically identical and biochemically similar to that of prostatic tissue.

Antigens↗
PubMed1981

Prostate antigen: a new potential marker for prostatic cancer.

A prostate-specific antigen, distinct from acid phosphatase, was identified by immunologic procedures in prostate tissues (normal, benign hypertrophic, and cancerous) and seminal plasma, as well as in sera of patients with prostatic cancer and of nude mice bearing human prostatic tumor. This antigen was shown by immunoperoxidase staining to be confined to epithelial cells comprising the prostatic ductal elements. Prostate antigen was purified from prostatic tissue and seminal plasma, and it was shown to have a molecular weight of 33,000-34,000 with no subunit component. The isoelectric point of purified antigen was around 6.9, though several unpurified isomers with different isoelectric points also were observed. Serum-borne prostate antigen showed a molecular weight of 90,000-100,000 but it exhibited a molecular weight of 36,000 in the presence of sodium dodecyl sulfate. A sandwich-type, peroxidase-linked immunosorbent assay capable of detecting 0.1 ng of the antigen per milliliter of blood was developed. With this technique, serum level of the antigen was found to increase in patients with prostatic cancer as compared with normal males. The prostate-specific antigen can be a useful marker for detection of prostatic cancer.

Antigens↗
PubMed1980

Fundamental biochemical and immunological aspects of prostatic acid phosphatase.

Prostatic acid phosphatase (PAP) was purified from human malignant prostate tissue by means of ammonium sulfate fractionation followed by sequential chromatographies of ion exchange, affinity column, and gel filtration. PAP has a molecular weight of 100,000 and consists of two subunits of 50,000. Owing, in part, to sialic acid contents in the molecule, PAP has multiple isoelectric points (pIs) at 4.2-5.5. In 0.2 M citrate, PAP has the highest affinity (Km 9.2 x 10(-5) M) in hydrolyzing alpha-naphthyl phosphate among the phosphomonoesters. Tartrate and heat at 37 degrees C for 2 hours almost completely inhibit PAP enzymic activity. By immunoprecipitate technique, anti-PAP heteroantiserum exhibited a distinct immunologic characteristics. Further, PAP possessed different antibody-binding site from enzyme hydrolytic site.

Acid Phosphatase↗
PubMed1980

A prostate antigen in sera of prostatic cancer patients.

A prostate antigen has been detected by a rocket immunoelectrophoresis technique in 17 of 219 sera obtained from patients with advanced prostatic cancer. Sera from 175 patients with nonprostatic cancers, including those with late-stage disease of the breast, lung, colon, rectum, stomach, and pancreas, were antigen negative as were 20 samples each from normal adults and age-matched males. Antigen in sera showed immunological identity with antigen in prostate tissue as determined by immunoprecipitation peak enhancement experiments. Using antibody affinity chromatography and radioimmunoprecipitation techniques, the antigen in sera was purified and subjected to sodium dodecyl sulfate electrophoresis; it exhibited a molecular weight of approximately 36,000, similar to that of antigen isolated from prostatic tissue.

Acid Phosphatase↗
PubMed1979

Purification of a human prostate specific antigen.

Rabbit antiserum raised against the crude extract of normal human prostatic tissue contained antibodies to a prostatic tissue-specific antigen as shown by immunoprecipitation techniques. Using this antiserum a prostate antigen was detected in normal, benign hypertrophic, and malignant prostatic tissues, but not in other human tissues. The prostate antigen was purified to homogeneity from prostatic tissues and showed a single protein band on analytical polyacrylamide gel electrophoresis and isoelectric focusing. This report thus presents the first demonstration of the purification of a prostate-specific antigen that does not represent prostatic acid phosphatase.

Antigens↗
PubMed1977

A clinicopathologic study of prognostic factors in cutaneous malignant melanoma.

Sex, size of the primary lesion, level of invasion at the primary site, clinical status of the regional lymph nodes at the time of diagnosis and whether or not the lymphatic or the blood vessels at the primary site were invaded by tumor cells are the prognostic factors found to influence the survival of patients with a cutaneous malignant melanoma. The last two factors were found to correlate with the level of invasion. Because of the high incidence of local recurrences after a small local excision, wide excision at the primary site of skin, subcutaneous tissue and fascia with skin graft should be the treatment of choice. The role of elective regional lymphadenectomy has to be questioned, as 51 per cent of the patients never required lymphadenectomy during the course of the disease, The higher incidence of satellitosis after such a procedure, elective lymph node dissection did not improve the survival. Therefore, it appears that regional lymph node dissection has a prognostic, rather than a therapeutic, role. From the time of the recurrence, it is clear that patients with systemic metastasis have the poorest prognosis. On the other hand, patients in whom satellitosis developed lived longer, but this was not statistically significant when compared with the survival of patients with a local recurrence or with regional lymph node metastasis; Early diagnosis should be emphasized because the two main factors that seem to influence survival are the depth of invasion and the size of the primary lesion. Finally, because the level of invasion and the status of the lymphatics and blood vessels seem to carry a high prognostic significance, each primary lesion should be examined pathologically with regard to these factors.

Adult↗