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Biomedical subjects

C W Lin

Publications and source records attributed to C W Lin.

At least 127 records · Page 7Linked to original sources
PubMed1989

Cycloheximide inhibits the induction of collagenase mRNA in chondrocytes exposed to synovial factors or recombinant interleukin-1.

Synoviocytes secrete "chondrocyte activating factors" (CAF) which, like recombinant interleukin-1 (IL-1), induce the synthesis of collagenase by cultures of articular chondrocytes. Enzyme synthesis is preceded by the appearance of collagenase mRNA some 3-5 hours after exposure of the chondrocytes to CAF or IL-1. Cycloheximide (CX) inhibits the appearance of this message in a dose-dependent manner. At a concentration of 5 micrograms/ml inhibition by CX is completely reversible, with superinduction being observed in certain experiments. Identification of the newly synthesised proteins which are required for collagenase mRNA induction would greatly advance our understanding of collagenase gene expression.

Animals↗
PubMed1989

Distinct requirements for activation at CCK-A and CCK-B/gastrin receptors: studies with a C-terminal hydrazide analogue of cholecystokinin tetrapeptide (30-33).

We describe here the properties of tert-butyloxycarbonyl-Trp-Leu-Asp-Phe-NHNH2 (A-57696), a C-terminal hydrazide analogue of tert-butyloxycarbonyl-CCK4 (Boc-Trp-Met-Asp-Phe-NH2), at four cholecystokinin (CCK) receptor-bearing tissues, the guinea pig pancreas and gall bladder (Type A), guinea pig cortex (Type B), and NCI-H345 cells, a human small cell lung cancer cell line that expresses CCK-B/gastrin receptors. Using 125I-Bolton-Hunter-cholecystokinin octapeptide (26-33) (125I-Bolton-Hunter-CCK8) as the radioligand, A-57696 was found to be selective for cortical CCK-B receptors (IC50 = 25 nM), compared with pancreatic CCK-A receptors (IC50 = 15 microM). A-57696 behaved as a competitive antagonist in reversing CCK8-stimulated pancreatic amylase secretion and phosphoinositide breakdown. By Schild analysis, its Kd was determined to be 4.7 and 6.8 microM in amylase and phosphoinositide assays, respectively. A-57696 (100 microM) did not elicit gall bladder contraction, and it inhibited contractions induced by CCK8. The Kd of A-57696 at gall bladder CCK-A receptors was 19 microM. In contrast, A-57696 behaved as a partial agonist (80% of maximal CCK8 response) in stimulating calcium mobilization at CCK-B/gastrin receptors on NCI-H345 cells. A-57696 and CCK8 inhibited each other in calcium mobilization experiments utilizing the fluorescent dye Indo-1. Stimulatory actions of CCK8 and A-57696 were reversed by the CCK-B-selective (R)-L-365,260 (100 nM), whereas at the same concentration, the CCK-A-selective (S)-L-365,260 was ineffective. Binding studies using 125I-Bolton-Hunter-CCK8 and 125I-gastrin indicated that binding sites labeled by these two ligands displayed similar affinities for CCK8, desulfated CCK8, gastrin, A-57696, and both enantiomers of L-365,260. A-57696 represents a new class of CCK-A peptide antagonist at guinea pig pancreas a new class of CCK-A peptide antagonist at guinea pig pancreas and gall bladder. Its contrasting functional activities at guinea pig CCK-A and CCK-B/gastrin receptors in a human tumor cell demonstrate that, in addition to the previously described differences in binding specificity for selective agonists and antagonists, CCK-A receptors and CCK-B/gastrin receptors have different requirements for activation.

Amino Acid Sequence↗
PubMed1988

Photodynamic effect in an experimental bladder tumor treated with intratumor injection of hematoporphyrin derivative.

Photodynamic therapy (PDT) is an experimental treatment modality for malignant tumors. It is based on the principle that a photosensitizer, such as hematoporphyrin derivative (HPD), is retained in higher concentrations in tumors than in surrounding nonmalignant tissues and that photoactivation of the sensitizer can be used to evoke tumor destruction. However, retention of the systemic injection of HPD is not limited to malignant tissues. This lack of specific tumor localization thus reduces the therapeutic ratio of the treatment and causes skin photosensitivity and possible systemic toxicity. Injection of HPD directly into the tumor, on the other hand, has been shown to yield higher levels of the drug in the tumor and lower levels in normal tissues, in comparison with systemic administration. In this study, we examined the photodynamic effect on s.c. implanted mouse bladder tumors subjected to intratumor (i.t.) and i.p. HPD injections. Tumor cell killing, measured by cell survival, was observed in both the it. and i.p. groups and was dependent on fluence and HPD dosage. However, no significant enhancement of cell killing was observed in the i.t. injected tumors, despite the higher porphyrin levels in these tumors. Histological examination of the effect of PDT on the blood vessels indicated that while cell death accompanied severe hemorrhage in the i.p. injected tumors, in the i.t. tumors there was much less hemorrhage and intact blood vessels remained. This observation suggests that with i.t. administration, direct photodynamic action may play a significant role in the tumor cell killing, in contrast to systemic administration, in which destruction of the blood vessels is believed to be the main cause of tumor destruction.

Animals↗
PubMed1988

Induction of collagenase mRNA in lapine articular chondrocytes by synovial factors and interleukin-1.

The cDNA probe H-9, originally constructed to recognize a portion of the mRNA for lapine synovial collagenase, also hybridized with a RNA of the same size (approximately 2.0 kb) isolated from activated lapine articular chondrocytes. Primary, monolayer cultures of lapine articular chondrocytes did not contain detectable amounts of this RNA, nor did they secrete measurable amounts of collagenase into their culture media. Following exposure to synovial factors, the chondrocytes contained high levels of collagenase mRNA, while their conditioned media had considerable collagenolytic activity. Collagenase mRNA started to appear in chondrocytes 3-5 h after treatment with the synovial material. Maximum levels occurred after 12-24 h. Recombinant human interleukin-1 also induced the appearance of this mRNA. We conclude that chondrocyte collagenase is likely to be the same gene product as synovial collagenase, and that its regulation by lapine articular chondrocytes probably occurs at a pretranslational level.

Animals↗
PubMed1988

Establishment and characterization of a doxorubicin-resistant human bladder cancer cell line (MGH-U1R).

A doxorubicin-resistant bladder cancer cell line has been established. This was accomplished by exposing an established human bladder tumor cell line, MGH-U1, to progressively higher concentrations of doxorubicin over a period of 12 months. The resistant cells, MGH-U1R, are nine times more resistant to doxorubicin and 30 times more resistant to daunorubicin than the parent cells. The MGH-U1R and the MGH-U1 cells have identical isozyme phenotypes. Compared to the parent cells, the resistant cells have a slower growth rate, lower confluent density, are more heterogeneous morphologically, and exhibit more chromosomal aberrations and rearrangements. The resistant cells may now be used as an experimental system for the search of means to overcome drug resistance in human bladder cancer.

Cell Division↗
PubMed1988

Detection of tumor cells in bladder washings by a monoclonal antibody to human bladder tumor-associated antigen.

We have conducted two studies to evaluate the efficacy of using a specific monoclonal antibody (McAb) to detect exfoliated tumor cells in bladder washings. This is a preliminary step toward the development of immunological methods to improve the cytologic detection of bladder carcinoma. In this study, McAb 3G2-C6 was used. The McAb reacts to a bladder tumor-associated cell-surface antigen expressed in bladder tumors of various grades. Bladder washings from patients with and without carcinoma were stained with the McAb using two different indirect immunofluorescence methods (Methods A and B). The results of the immunological studies were compared with those obtained from the cytology laboratory and these in turn, were evaluated against the histopathological diagnosis of respective patients at the time the samples were taken. Immunofluorescence method A detected positive cells in 87% (56/64) of specimens from bladder cancer patients, including 18 of 19 from patients with grade 1 tumor. This method also had a low false-positive rate; only one of 17 specimens from patients with other urinary disorders had positively reacting cells. Immunofluorescence method B, evaluating a second group of specimens, detected positive cells in 68% (15/22) of specimens from patients with carcinoma, and in only one of 17 controls. However, it also identified positive cells in specimens from patients with chronic cystitis and urinary calculi. Overall the results of these studies indicate that the McAb method is superior to the routine cytology in detecting tumor cells in bladder washing specimens. More work must be done, however, to improve the specificity of the method before it can be used as an aid for routine tumor detection.

Antibodies, Monoclonal↗
PubMed1988

Intratumor injection as a more effective means of porphyrin administration for photodynamic therapy.

Photodynamic therapy (PDT) with hematoporphyrin derivative (HpD) as the photosensitizer is a promising new cancer treatment. The major drawback of this procedure is the resulting skin photosensitivity. Patients must remain in subdued light for four to six weeks to avoid cutaneous phototoxicity. In this study, we examine the possibility of reducing the skin photosensitization while maintaining the tumor phototoxic effect by administering the drug directly into the tumor. A subcutaneously implanted mouse bladder tumor (MBT-2) was used. HpD was administered either intraperitoneally (I.P.; 20 mg./kg. b.w.) or by intratumor injection (I.T.; 0.4 mg./cc tumor). The concentrations of HpD in tumor and various tissues (skin, muscle, liver, spleen, kidney, bladder and whole blood) were analyzed at various times after the injection, by 3H-HpD method and by a fluorometric method. Results indicated that at three to 96 hours after the administration, porphyrin levels in tumor were about three to 15 times higher by I.T. than by I.P. injection, while the concentrations in skin and other tissues were 1.3 to 10 times lower. Consequently, at 24 hours after injection ratios between tumor to skin porphyrin were 14 to 92 times higher for I.T. than I.P. injection. Higher porphyrin levels in tumor and lower in normal tissues would indicate lower skin photosensitivity, systemic cytotoxicity and possible greater tumor photosensitivity. This method of porphyrin administration may be useful for the PDT of certain single lesions that are accessible for direct injection.

Animals↗
PubMed1987

Photodynamic therapy with hematoporphyrin derivative in the treatment of superficial transitional-cell carcinoma of the bladder.

Photodynamic therapy involves light-induced destruction of tumors containing a photosensitizer such as hematoporphyrin derivative. We conducted a collaborative study to evaluate the efficacy of this form of therapy in treating superficial transitional-cell carcinoma of the bladder. Thirty-seven patients were evaluated and 20 were selected for treatment. A total of 50 papillary tumors and 3 areas of carcinoma in situ were treated. All except two tumors were smaller than 2.5 cm. Assessments for treatment response and toxicity were carried out three months after treatment. The initial diagnosis of one patient was revised after the biopsy material was reviewed, and this patient was not included in the analysis. Complete eradication of all tumors was observed in 9 of 19 patients (47 percent), including those with carcinoma in situ. In the remaining 10 of these 19 patients, 13 tumors could not be eradicated (the overall eradication rate was 37 of 50 tumors [74 percent]), but 9 of the 10 patients had a reduction in tumor size, number, or both of 50 percent or more. We conclude that photodynamic therapy is useful in the treatment of superficial transitional-cell carcinoma of the bladder, but controlled trials will be required to define its place in the treatment of cancer.

Adult↗
PubMed1986

Distribution, retention, and phototoxicity of hematoporphyrin derivative in a rat glioma. Intraneoplastic versus intraperitoneal injection.

The distribution, retention, and phototoxicity of the sensitizer hematoporphyrin derivative (HPD) were studied following intraperitoneal and direct intraneoplastic injections of the agent into subcutaneous or intracerebral gliosarcomas in rats. Forty-eight hours after intraperitoneal injection, the ratio of tritiated (3H) HPD in subcutaneous tumor: adjacent normal skin was about 1.4:1 and the ratio in tumor: normal brain was 3:1. In contrast, direct injection of 3H-HPD into subcutaneous tumors resulted in tumor: adjacent normal skin concentration ratios of approximately 44:1 and tumor: normal brain ratios of about 61:1. For rats bearing intracerebral gliosarcomas, intraperitoneal administration of 3H-HPD resulted in approximately 1.3-fold sensitization in tumor tissue relative to adjacent edematous brain. In contrast, after direct injection into intracerebral tumors, the tumor: adjacent edematous brain and tumor: skin 3H-HPD ratios were 3:1 and 32:1, respectively. In all cases, 3H-HPD was found in every portion of the tumor, even at a distance from the injection site. For the 3H-HPD doses used in this study, after direct injection both subcutaneous and intracerebral tumor tissue contained about three to four times more 3H-HPD than tumors in rats receiving intraperitoneal 3H-HPD. Both in vitro and in vivo clonogenic assays demonstrated that the photodynamic inactivation of the tumors was significantly greater after direct injection than after intraperitoneal injection.

Animals↗
PubMed1986

Cholecystokinin receptors: relationships among phosphoinositide breakdown, amylase release and receptor affinity in pancreas.

The gut hormone cholecystokinin (CCK) octapeptide stimulates the release of amylase from exocrine pancreas, a process believed to be the result of the breakdown of phosphatidylinositol lipids. To examine further the relationship between phosphoinositide (PI) breakdown and amylase release, we have investigated the effect of N-terminally protected CCK C-terminal fragments in these systems using guinea-pig pancreatic lobules. There was a good correlation between the ability of these fragments to elicit amylase release and their potency in enhancing PI breakdown. In general, the EC50 for amylase release is 10-fold lower than the EC50 for PI breakdown. In addition, a good correlation existed between amylase release and the affinity of CCK fragments for [125I]Bolton Hunter-CCK octapeptide binding sites in pancreatic membranes. We also discovered that N-carbobenzyloxy-CCK tetrapeptide was relatively inefficient in causing PI breakdown, but it caused a near maximal stimulation in amylase release. These findings might reflect an amplification mechanism between PI breakdown and amylase release or that N-carbobenzyloxy-CCK tetrapeptide-induced amylase release is independent of PI breakdown.

Amylases↗
PubMed1985

Vascular invasion as a prognosticator of metastatic disease in nonseminomatous germ cell tumors of the testis. Importance in "surveillance only" protocols.

Forty-five nonseminomatous germ cell carcinomas of the testis were evaluated retrospectively to define the biologic features associated with the occurrence of metastatic disease. A statistical analysis of several pertinent clinical and pathologic factors was performed. The factors evaluated included: duration of symptoms before diagnosis, serum level of alpha-fetoprotein, serum or urinary level of human chorionic gonadotropin, testicular weight, extent of local tumor (pathologic T stage), and vascular invasion at the primary site. In each case, metastases were documented by a retroperitoneal node dissection, other biopsies, or by chest films. In 29 tumors with vascular invasion, 25 patients were seen with metastatic disease. In 16 tumors without vascular invasion, 3 patients demonstrated metastasis. The presence or absence of vascular invasion was strongly correlated with concomitant lymph node involvement or subsequent appearance of other metastatic disease (chi-square = 17.19). Additionally, vascular invasion in bifactoral++ analysis with tumor size and pathologic T stage proved a significant prognosticator even in low-staged (chi-square = 8.48) and small tumors (chi-square = 8.13). The implications of these findings, both as an adjunct to the staging of nonseminomatous germ cell tumors and in the management of clinical Stage I lesions, are discussed.

Adolescent↗
PubMed1985

Characterization of cholecystokinin receptor sites in guinea-pig cortical membranes using [125I]Bolton Hunter-cholecystokinin octapeptide.

[125I]Bolton Hunter-cholecystokinin octapeptide (BH-CCK8) has been prepared using a modified method and was used to study putative cholecystokinin (CCK) receptor sites in the guinea-pig cerebral cortex. Specific binding of [125I]BH-CCK8, defined as the difference in binding in the absence and presence of 10(-6) M CCK8, was 70% of total binding. In saturation experiments, the apparent dissociation constant (Kd) was 1 nM and total binding capacity was 28 fmol/mg of protein. In association experiments, conducted at 30 degrees C, binding of [125I]BH-CCIK8 reached equilibrium in approximately 150 min. Binding was stable for 4 hr and was reversed by the addition of unlabeled CCK8-sulfated. Dissociation of bound ligand was biphasic and the apparent T1/2 was 45 min. Analyses of kinetic experiments yielded an association rate constant of 0.58 X 10(8) min-1 M-1 and a dissociation rate constant for the slower component of 0.012 min-1. Dithiothreitol increased and N-ethylmaleimide decreased specific binding of [125I]BH-CCK8, indicating that CCK receptor sites involve sulfhydryl groups. In competition experiments, the potency of CCK4 was enhanced 50-fold with addition of protease inhibitors. The rank order of CCK-related peptides was CCK8-sulfated greater than or equal to Gastrin 17 greater than or equal to CCK33 greater than CCK4 greater than or equal to CCK8-desulfated. Proglumide, a proposed CCK antagonist in the periphery and brain, was inactive at 10(-3) M. The specificity of [125I]BH-CCK8 binding sites are similar to that reported for [125I]BH-CCK33.

Animals↗
PubMed1985

Effect of 514.5-nm argon ion laser radiation on hematoporphyrin derivative-treated bladder tumor cells in vitro and in vivo.

The therapeutic effect of hematoporphyrin derivative (HpD) plus 514.5-nm argon ion laser radiation was compared to HpD plus 630-nm argon ion laser-pumped dye laser radiation in experimental urinary bladder transitional cell carcinoma models. Cultured human bladder cancer cells (EJ) containing HpD were 2.8-fold more sensitive to 514.5-nm radiation than to 630-nm radiation as measured by clonogenic capacity. The relative effectiveness of 514.5-nm versus 630-nm light was approximately proportional to the spectral absorbance for cell-bound HpD at these wavelengths. HpD-sensitized photoirradiation was studied in solid tumors produced by a) the subcutaneous inoculation of cells from murine bladder tumors induced by N-[4-(5-nitro-2-furyl)-2-thiazoyl]formamide (CAS: 24554-26-5) into female C3H mice (MBT-2 tumor) and b) the intravesical instillation of N-methyl-N-nitrosourea (CAS: 684-93-5) into the urinary bladders of female Wistar rats. The tumors were exposed to 144 J/cm2 laser light 24-48 hours following ip injection of 20 mg HpD/kg body weight. By 24-48 hours, animals that received HpD and light of either wavelength had partially or completely necrosed tumors. Control groups showed no necrotic changes. Regression of MBT-2 tumors was also investigated. Seven of 14 and 6 of 12 animals had nonpalpable tumors 1 week after treatment with 514.5-nm and 630-nm light, respectively. Tumors in control groups demonstrated no regression. Spectral transmittance from 630 nm to 514.5 nm decreased by about 4% for 130- to 160-micron-thick sections of canine urothelium and bladder submucosa-muscularis. The results of this study indicate that HpD plus 514.5-nm laser radiation may be an effective treatment for small or superficial malignant lesions of the urinary bladder.

Animals↗
PubMed1985

Production and characterization of mouse monoclonal antibodies to human bladder tumor-associated antigens.

Monoclonal antibodies (McAbs) to human bladder carcinoma were generated by fusion of NS-1 mouse myeloma cells with spleen cells from BALB/c mice immunized with either cultured human bladder cancer cells or cells obtained from a fresh surgically removed bladder tumor. Four hybridomas which reacted strongly with bladder tumor cells and not to normal skin fibroblasts or urothelial cells were identified and cloned by limiting dilution to obtain monoclonality. One McAb, 3G2-C6, raised with cultured tumor bladder cells MGH-U1 (EJ) as the immunogen reacted more strongly to the bladder tumor lines tested than any of the other McAbs resulting from various fusion experiments. Hybridoma 3G2-C6 was found to secrete murine immunoglobulin G1 and to produce high titer ascites fluid when grown in BALB/c mice. Results from quantitative enzyme-linked immunosorbent assays on a panel of more than 35 cell lines demonstrated that McAb 3G2-C6 reacted with several bladder tumor cell lines 50 to 90 times more than with normal transitional urothelium. Two kidney and two testicular tumor lines also bound 10 times more 3G2-C6 than with normal cells. The 3G2-C6 antigen was only marginally detected on a number of other cancer and noncancerous cells tested such as breast and lung tumor cells, melanoma, fetal cells, and peripheral blood lymphocytes. To identify the antigen 125I-labeled membrane components from MGH-U1 cells were extracted with detergent, immunoprecipitated with Protein-A bound 3G2-C6, and analyzed by sodium dodecyl sulfate-gel electrophoresis. This revealed that McAb 3G2-C6 binds to a Mr 90,000 cell surface component. Indirect immunofluorescence microscopy with fluorescein isothiocyanate-anti-mouse immunoglobulin G also identified the antigen on the surface of cultured and fresh tumor cells and detected the antigen on 16 of 17 Grade 3 bladder tumor specimens as well as on some kidney and testicular tumor cells. This study confirms the potential of the hybridoma technique for producing McAbs capable of identifying tumor associated antigens which may be useful in the diagnosis and treatment of bladder cancer.

Animals↗
PubMed1985

Photosensitization and split-dose recovery in cultured human urinary bladder carcinoma cells containing nonexchangeable hematoporphyrin derivative.

The photosensitization and survival recovery of cultured EJ human urinary bladder carcinoma cells containing nonexchangeable hematoporphyrin derivative (HPD) were studied. Cultures were incubated at 37 degrees C in growth medium supplemented with HPD (50 micrograms/ml) and 5% fetal bovine serum for 12 h followed by incubation in HPD-free medium containing 5% fetal bovine serum for 9 or 18 h. The levels of porphyrin remaining in the cells (termed the "nonexchangeable" intracellular porphyrin component) were not significantly different at these times, and as a result sensitivities to broad-band red light (greater than 580 nm) were also identical. Shouldered survival curves were obtained in each case, indicating the ability to accumulate sublethal photodamage. Recovery from photosensitized damage using a split-dose technique was examined. Single, attached, asynchronously growing cells containing nonexchangeable HPD (12 h HPD uptake plus 9 h in porphyrin-free medium) were exposed to red light (1.2 kJ/sq m) and, after various intervals at 37 degrees C in the dark, a second dose of 1.2 kJ/sq m. Survival rapidly increased and reached a maximum at about 9 h between light doses. Analysis of dose-response curves revealed a partial reappearance of the curve shoulder (Dq = 0.22 kJ/sq m) and a markedly reduced curve slope (D0 = 0.82 kJ/sq m) for fractionated irradiations with a 9-h interval in comparison with graded, single light exposures (Dq = 0.48 kJ/sq m; D0 = 0.41 kJ/sq m). These observations suggest that the cells developed an increased tolerance to photosensitized damage after prior HPD-light treatment. No significant change in intracellular HPD levels between irradiations was detected, indicating that the increased survival was not due to a loss of sensitizer from inside the cells. These results demonstrate that EJ cells accumulate and recover from HPD-sensitized photodamage; analogous to the accumulation and recovery from sublethal damage (Elkind recovery) in other mammalian cultures treated with ionizing radiation.

Cell Survival↗
PubMed1985

Establishment and characterization of four human bladder tumor cell lines and sublines with different degrees of malignancy.

We have established four human bladder tumor cultures, designated MGH-U1 to -U4 (also known as EJ, HM, RN, and RB in some previous reports). All have been grown in culture for over 30 passages and were free of Mycoplasma contamination. Characterizations of these cell lines were performed. These include isozyme profile, morphology with light and scanning electron microscopes, karyotype, growth rate, DNA content by flow cytometry, presence of cell surface ABH isoantigens, tumorigenicity in nude mice, lactic acid dehydrogenase isozymes, and colony formation in soft agar. Results obtained from these characterizations confirm that MGH-U1 and -U2 are sublines of a previously established bladder tumor cell line, T-24. These results also show that MGH-U3 and -U4, derived respectively from a grade 1 tumor and an urothelium biopsy with severe atypia, are likely to be independent human bladder cell lines and different from other transitional cell bladder carcinoma cell lines reported. The study further demonstrates that these four cell lines/sublines have different degrees of malignancy and a close correlation, in biological and malignant characteristics, between the cells in culture and those in the original tumors. Therefore these cultures may represent cells at different stages of malignant progression. These can be useful models for studies of the development and progression of bladder tumors and detection and treatment of bladder tumors of different grades and stages.

ABO Blood-Group System↗