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C W Lin

Publications and source records attributed to C W Lin.

At least 145 records · Page 8Linked to original sources
PubMed1984

Identification of vessels by lectin-immunoperoxidase staining of endothelium: possible applications in urogenital malignancies.

Ulex europaeus agglutinin I binds specifically to vascular endothelium of various human tissues irrespective of the blood group type or secretive status of the tissue. Using this property, we have developed an immunoperoxidase technique to identify vessel structures in urogenital tissues. Most vessels in malignant and nonmalignant tissues of bladder, prostate and testis of different blood types (A, B, AB and O) can be readily identified by this method. This technique has potential application in detecting tumor cell invasion of vessels and in studying distribution of vessels in relation to various normal and pathological events.

ABO Blood-Group System↗
PubMed1984

Cystoscopic fluorescence detector for photodetection of bladder carcinoma with hematoporphyrin derivative.

Hematoporphyrin derivative, a fluorogenic substance, tends to accumulate at higher levels in most tumor tissues after intravenous injection. These properties provide a potential application for the detection of malignant tumors. We report the development and in vitro evaluation of an instrument designed to excite and detect low levels of hematoporphyrin derivative fluorescence emitted by tumor cells in the bladder after hematoporphyrin derivative administration. The light source of the instrument for specific hematoporphyrin derivative excitation is at a wavelength of 405 nanometers. Optical fibers for both the excitation and detection of fluorescence were bundled in a single 7 French ureteral catheter which can be inserted into a standard cystoscope. The fluorescence is initially detected as an electrical signal which is amplified and then converted into an audio signal. The interference of the cystoscope illuminating white light to the fluorescence signal is eliminated by a phase-sensitive electronic circuit. The instrument thus allows simultaneous viewing of the bladder and detection of hematoporphyrin derivative fluorescence produced from tumor tissues. In vitro testings using hematoporphyrin derivative solutions on filter paper indicated that the instrument detects as little as 30 nanograms per milliliter of hematoporphyrin derivative and has relatively low noise levels from normal tissues. The utility of this instrument for hematoporphyrin derivative photodetection of small tumors and carcinoma in situ in bladder is currently under clinical evaluation.

Animals↗
PubMed1984

Correlation of vascular invasion and metastasis in germ cell tumors of testis--a preliminary report.

A preliminary study was conducted to correlate vascular invasion with metastasis in testicular tumors. A lectin-immunoperoxidase procedure was used to identify the vessels. Together with standard hematoxylin and eosin staining, the presence of tumor cells in vessels was detected. Primary tumor specimens from 37 cases and retroperitoneal lymph nodes from 10 cases of germ cell tumors were studied. The results showed good correlations between vascular invasion in primary tumors and metastasis to lymph nodes in nonseminomatous germ cell tumors, and between vascular invasion in retroperitoneal lymph nodes and the presence of other metastases. Eight of the 9 nonseminomatous germ cell tumor patients with vascular invasion had metastases, and all 4 patients that had vascular invasion in the lymph nodes had other metastases. However, there seemed to be no correlation between vascular invasion and clinical staging in cases with seminoma in which retroperitoneal lymph node dissection was not performed. These observations, although based on a limited number of cases, warrant more extensive investigations.

Blood Vessels↗
PubMed1984

Visualization of urothelial blood group isoantigens A and B using direct biotin-labeled antibodies and avidin-biotin-peroxidase complex.

The loss of blood group isoantigens from the surface of bladder tumor cells has been correlated with the potential invasiveness of the tumor. Development of simple and reliable methods for detection of these isoantigens should facilitate the general clinical use of this test for predicting malignant potential in low grade, low stage cancer of the bladder. We now report a direct peroxidase technique for the detection of isoantigens A and B by utilizing the specific interaction between biotin and avidin, and the capability of labeling a single antibody with multiple biotin molecules. Antibodies specific to the isoantigens A and B were purified from human antisera by affinity chromatography using an immunoabsorbent containing chemically synthesized antigenic determinants. The purified antibodies were directly labeled with biotin. An avidin-biotin-peroxidase complex was used to bind the biotinylated antibody for the peroxidase staining reaction of the isoantigens on tissue section. Application of this technique to formalin-fixed, paraffin-embedded bladder tissue and tumor sections yielded specific and strong stainings of the isoantigens with low background staining. The potential clinical application of this method requires further evaluation.

ABO Blood-Group System↗
PubMed1984

Photodynamic inactivation of cultured bladder tumor cells: a preliminary study of the effects of porphyrin aggregation.

This study was designed to determine the influence, if any, of intracellular porphyrin aggregation upon in vitro photosensitivity. HpD uptake conditions were manipulated in such a way as to yield three experimental groups, each containing equal levels of cellular porphyrins but having different porphyrin aggregation status. Aggregation status was determined through comparison of the spectral properties of intact cells. Subsequent exposure to red light resulted in a family of survival curves which generally corresponded to cellular HpD fluorescence yields and optical densities (indicators of aggregation status). These data suggest that porphyrin aggregation within the cell may be partially responsible for the observed differential photosensitivity following various uptake conditions.

Biological Transport↗
PubMed1983

Evaluation of prostate specific acid phosphatase and prostate specific antigen in identification of prostatic cancer.

The peroxidase-anti-peroxidase technique was used to stain for prostate specific acid phosphatase and prostate specific antigen in 12 patients with primary tumors and in 12 patients with metastases in whom the nature of the tumor was in doubt after routine histopathological studies. Nine of the primary tumors were positive for both markers and an additional 2 tumors stained for prostate specific antigen only. Six metastatic lesions stained for both markers and a seventh for prostate specific antigen alone. Thus, 11 of 12 primary tumors and 7 of 12 metastases studied were proved to be of prostatic orgin. While the peroxidase staining was sometimes weak and uneven this method, using prostate specific antigen and prostate specific acid phosphatase, allowed for ready identification of metastases. The heterogeneity of the tumors in regard to these 2 prostate markers is demonstrated, and the value of staining for prostate specific acid phosphatase and prostate specific antigen is emphasized.

Acid Phosphatase↗
PubMed1983

The determination of dissociation constants for substance P and substance P analogues in the guinea pig ileum by pharmacological procedures.

The dissociation constants (Kd values) of substance P (SP), physalaemin, kassinin, and SP analogues acting on SP receptors in guinea pig ileal longitudinal muscle strips were determined by the pharmacological procedures of Furchgott [Adv. Drug Res. 3:21-55 (1966)]. This method involves analysis of the concentration-response data before and after fractional inactivation of receptors with phenoxybenzamine (2 X 10(-5) M). Estimations of the Kd values for SP were similar when phenoxybenzamine was incubated for 10, 13, or 15 min. Coincubation with high concentrations of SP protected against receptor inactivation with phenoxybenzamine, but bradykinin and serotonin did not cross-protect SP receptors. Kd values for SP were similar when trypsin was substituted for phenoxybenzamine [Kd = 8.1 +/- 4 nM (n = 9) versus 10 +/- 6 nM (n = 5)]. In atropinized preparations the Kd values obtained for physalaemin were similar to those obtained for untreated preparations [Kd = 8.0 +/- 3.6 nM (n = 5) and 12.6 +/- 3 nM (n = 4), respectively]. The effects of phenoxybenzamine on concentration-response curves for kassinin showed greater shifts to the right with phenoxybenzamine. This indicated that kassinin may interact with another population of receptors, in addition to the sites that SP and other analogues bind. A direct correlation was found between EC50 values and Kd values and Kd values for SP and SP analogues. It was estimated that, for SP, a 20% receptor occupancy is required to elicit a 50% response.

Animals↗
PubMed1983

Distribution of histaminase in human tumor tissues. An immunohistochemical study.

Tissue samples from 125 cases of a variety of human malignancies and benign conditions were examined for the presence of histaminase by the immunoperoxidase method on conventional pathological specimens. Histaminase was found diffusely in the cytoplasm of cancer cells of primary and metastatic tumors of lung, thyroid gland, pancreas, stomach, esophagus, ovary and pharynx. Histaminase-positive cases were also found in carcinoids, dysgerminomas and in melanoma. The incidence of positive histaminase staining in epithelial malignancies overall was 28/84, and those in sarcoma as well as in benign conditions were 1/22 and 0/19, respectively, excluding placental decidual cells and eosinophils intermingled in the tissues. No significant difference in the incidence of histaminase was found by histological type or by degree of cellular differentiation. The present results thus provided another direct evidence for the production of histaminase by many kinds of tumor cells.

Amine Oxidase (Copper-Containing)↗
PubMed1982

Rat bladder isograft model for focal carcinoma.

A model for focal bladder carcinoma in rats was developed with the use of an isograft technique. Bladder tumors developed by carcinogen induction with FANFT or MNU were grafted to bladders of syngeneic rats. Ninety-six per cent (56 our of 58) of the grafts were taken and 83 per cent (34 out of 41) of the grafted tumors remained neoplastic. Most of the grafts from FANFT-induced tumor remained localized at the original site whereas many from the MNU-induced tumor spread beyond the original graft area. The model system may be useful for the evaluation of chemotherapeutic agents as well as for the studies of basic mechanisms of tumor growth and spreading.

Animals↗
PubMed1982

Immunohistochemical identification of prostatic acid phosphatase: correlation of tumor grade with acid phosphatase distribution.

The localization and distribution of prostatic specific acid phosphatase (PSAP) in normal, hyperplastic and neoplastic prostates were studied by specific immunohistochemical of normal and hyperplastic prostates. In adenocarcinoma of the prostate, a correlation of the PSAP staining with the degree of differentiation and the ability of the tumor to form a gland was observed: more intense and uniform staining in well differentiated tumors and less intense and more variable stains in poorly differentiated tumors. The same correlation was also observed in tumors metastasized to lymph nodes and other organs.

Acid Phosphatase↗
PubMed1981

Tumor and placental histaminase, II A procedure for radioimmunoassay.

Histaminase (diamine oxidase) is an enzyme associated with pregnancy and with a number of human cancers. In pregnancy, the enzyme is produced by the decidual cells of the placenta. Histaminase of the placenta is biochemically and immunologically identical to that of cancer, Based on this, a radioimmunoassay procedure for histaminase has been developed. The high affinity monospecific antiserum for the assay was obtained from rabbits by injecting with homogeneous histaminase purified from placenta by affinity chromatography. Radioactive labeling of histaminase was carried out by iodination with 125I using chloramine T as the oxidizing agent. The iodination yielded [125I]-histamine of high specific radioactivity (20 microCi/microgram protein) with no apparent affect on the immunologic affinity. For separating the antibody-antigen complex from the unbound antigen, a second antibody bound to polyacrylamide beads was most effective at high antiserum dilutions. The assay had a working range of 0.3 to 80 microgram/ml and a minimal detectable quantity of 0.15 ng/ml. Compared to the enzymatic assay with [14C] putrescine as substrate, the radioimmunoassay procedure is about 70 times more sensitive. Measurements of histamine in placental extracts and malignant effusions using both radioimmunoassay and enzyme assay demonstrated that the two methods were highly correlated, thus providing evidence for the specificity of the radioimmunoassay. This procedure will be useful in future studies of histaminase as a biochemical marker for human cancer and for the elucidation of the significance of this enzyme is pregnancy and in neoplasia.

Amine Oxidase (Copper-Containing)↗
PubMed1981

Tumor and placental histaminase, I. affinity chromatography purification and characterization of the placental enzyme.

Histaminase (diamine oxidase) is an enzyme produced at very high levels by the decidua of the placenta and is found to be associated with a number of human cancers. A procedure for the affinity chromatography purification of this enzyme is described. In this procedure, cadaverine-AH-sepharose was used to bind the enzyme in the placental extract. After extensive washing of the column with 2.5% Triton X-100 in 1 M NaCl, the enzyme was released from the column by 0.1 N chromotropic acid. This purification, essentially a one step procedure, provided 1800-fold purification, and yielded mg quantities of histaminase, homogeneous by SDS-gel electrophoresis and immunodiffusion tests. The procedure usually recovered more than 40% of the enzyme applied and the specific activity of the final enzyme preparation was around 5000 units/mg protein. SDS-gel electrophoresis of the enzyme in different concentrations of acrylamide indicated that the subunit molecular weight of histaminase was about 90,000. Isoelectric focusing of the enzyme in polyacrylamide gel revealed 5 major enzyme components. Results of amino acid analyses indicated that the enzyme had a low content of sulfur-containing amino acids and a relatively high content of dicarboxylic amino acids. The availability of this purification will be useful for the development of immunological methods for detections and quantitation of this enzyme in specimens from cancer patients.

Amine Oxidase (Copper-Containing)↗