Search PubMed⌕ Search

Biomedical subjects

J Chin

Publications and source records attributed to J Chin.

At least 145 records · Page 8Linked to original sources
PubMed1987

Identification of a high-affinity receptor for native human interleukin 1 beta and interleukin 1 alpha on normal human lung fibroblasts.

Native human IL-1 beta and IL-1 alpha stimulated prostaglandin E2 secretion by human embryonic lung fibroblasts at half-maximal concentrations of 3 +/- 1.2 pM (+/- SEM) and 10 +/- 2.3 pM, respectively. In contrast to the 20-50-fold lower affinities previously found for IL-1-R on 3T3 cells as well as murine and human lymphoblastoid lines, monoiodo 125I-IL-1 beta bound to normal human fibroblasts with a Kd of 8.4 +/- 4.1 pM in direct binding experiments, and with a Ki of 11.2 +/- 2.8 pM in competitive binding experiments. IL-1 alpha bound to the receptor identified by 125I-IL-1 beta with a Ki of 50 +/- 18 pM. The receptor exhibited homogeneous affinity for IL-1 beta or IL-1 alpha. The receptor did not recognize IL-2, IFN-gamma, tumor necrosis factor alpha, a functionally related monokine, or bovine acidic fibroblast growth factor, a structurally related mediator. Comparison of the biological response curves and binding curves obtained for IL-1 alpha and IL-1 beta showed that they were parallel and that 10-15% occupancy of the estimated 3,000 sites by either species of IL-1 was sufficient to give half-maximal stimulation of prostaglandin E2 secretion. Thus, the amount of apparent signal amplification observed on fibroblasts was considerably lower than the 100-100,000 fold amplification previously reported for lymphoid lines. Crosslinking experiments revealed a major band with a corrected molecular mass of approximately 80 kD and a minor band of approximately 200 kD. Labeling of these bands was blocked by IL-1 beta and IL-1 alpha but not by IL-2, IFN-gamma, or tumor necrosis factor alpha. These results demonstrate that normal human embryonic lung fibroblasts bear IL-1-R of sufficiently high affinity to mediate their biological responsiveness to low picomolar concentrations of IL-1 beta and IL-1 alpha and are consistent with the existence of a single receptor mediating the biological properties of both human IL-1 species.

Binding, Competitive↗
PubMed1987

Reactivity of monoclonal anti-human pancreatic carcinoma antibodies AR2-20 and AR1-28 with tumors of nonpancreatic origin.

The reactivity of two IgG1 murine monoclonal antibodies, AR2-20 and AR1-28 directed against the RWP-1 and RWP-2 human pancreatic cell lines was evaluated with paraffin sections of nonpancreatic human carcinomas. These monoclonal antibodies, which are directed against a 200-kd glycoprotein, and which did not stain normal tissues, were both reactive with 6 of 116 neoplasms (6 of 103 carcinomas) by indirect immunofluorescent histochemistry. This contrasts with the positive incidence of staining obtained with 29 of 34 human pancreatic adenocarcinomas. The two antibodies have specificities different from those previously described that reacted with pancreatic neoplasms. The significance of these findings is discussed with respect to the use of these antibodies in a diagnostic panel.

Antibodies, Monoclonal↗
PubMed1986

Experience of a Canadian multi-organ transplant service.

Organ transplantation has become the treatment of choice for selected patients with end-stage failure of the heart, liver or kidneys. The expanding role for organ transplantation, however, has led to a corresponding increase in the complexity of patient management. In response to these changes, University Hospital, London, Ont., has established an interdisciplinary multi-organ transplant service (MOTS). MOTS coordinates donor organ procurement and patient management. Donor organs have been retrieved from as far south as Dalton, Georgia, as far west as Calgary and as far east as Halifax. As of Dec. 31, 1985, 485 transplants had been performed, including 387 kidney transplants, 51 heart transplants, 3 heart/lung transplants, 43 liver transplants (in adults and children) and 1 pancreas transplant. With current immunosuppressive protocols MOTS projects 1-year patient survival rates of 95% after kidney transplantation, 88% after heart transplantation and 81% after liver transplantation. Patient rehabilitation has been excellent.

Adult↗
PubMed1986

Purification to homogeneity and amino acid sequence analysis of two anionic species of human interleukin 1.

Two anionic species of human IL-1 have been purified to homogeneity. These molecules were characterized as having pI of 5.4 and 5.2 and molecular weights identical to IL-1/6.8 (17,500). The specific activities of IL-1/5.4 and IL-1/5.2, as measured in the mouse thymocyte co-mitogenic assay, were identical to that of IL-1/6.8, namely 1.2 X 10(7) U/mg, with half-maximal stimulation observed at 2 X 10(-11) M. IL-1/5.4 and IL-1/5.2 were found to be antigenically distinct from IL-1/6.8 in an ELISA. IL-1/5.4 was structurally distinct from IL-1/6.8 based on reverse-phase HPLC or CNBr peptides. Intact IL-1/5.2 and three intact CNBr peptides of IL-1/5.4 were sequenced, with the identification of 74 amino acid residues. These sequences were found to correspond exactly with the amino acid sequence deduced from the IL-1-alpha cDNA reported by March et al.

Amino Acid Sequence↗
PubMed1986

Immunocytochemical detection of interleukin 1 within stimulated human monocytes.

We have used synthetic peptides coupled to KLH to raise high titer antisera to human IL-1 beta, and in the present report show the usefulness of these sera for immunocytochemical analyses of IL-1 production. Using indirect immunofluorescence, we have been able to specifically identify IL-1 within human monocytes and to monitor its accumulation with time. After indirect immunofluorescent staining of LPS- and PHA-stimulated mononuclear cell cultures, intense cytoplasmic fluorescence was observed in 93% of the monocytes, but not in lymphocytes or platelets present in the same preparation. Unstimulated monocytes did not contain immunocytochemically detectable IL-1. When put into culture, however, some of the otherwise unstimulated monocytes subsequently showed a transient accumulation of intracellular IL-1. Monocytes cultured in the presence of LPS and PHA exhibited detectable fluorescence after 2.5 h, and the fluorescent intensity of these cells continued to increase over the course of 21 h. Fluorescent staining was abolished by preincubation of the sera with relevant but not irrelevant peptide, and while preimmune or anti-KLH serum produced no staining, antisera against either the amino terminus or an internal region of IL-1 beta produced identical staining patterns. Immunoblot analyses of lysates from stimulated monocytes showed that the antisera against IL-1 recognize a single intracellular species with an apparent molecular weight (33 kD) similar to that predicted for IL-1 precursor from the nucleotide sequence of IL-1 cDNA. The ability to specifically identify and immunocytochemically localize IL-1 within producing cells should prove extremely useful for studying the in situ production of IL-1 in immune-based and inflammatory diseases.

Cell Adhesion↗
PubMed1986

The incidence of toxic shock syndrome in Northern California. 1972 through 1983.

In its 1982 report on toxic shock syndrome, the institute of Medicine, Washington, DC, identified population-based studies of the incidence of toxic shock syndrome over time based on hospital records as being a high priority for further research. We conducted such a study using records of hospitalizations in Northern California Kaiser-Permanente Medical Care Program facilities for the period from 1972 through 1983 among women and men aged 15 through 34 for illnesses considered possibly to be toxic shock syndrome. Of 6,688 hospitalizations reviewed, 54 were considered definite cases of toxic shock syndrome, and an additional nine were considered probable toxic shock syndrome. Four definite cases of toxic shock syndrome occurred in men, and 50 in women. The overall incidence of definite hospitalized toxic shock syndrome in men was 0.1 per 100,000 person-years, and in women 1.5 per 100,000 person-years. In women, an increase in the incidence of toxic shock syndrome was apparent by 1977; the rate peaked in 1980, decreased slightly in 1981 and 1982, and then almost doubled again in 1983. The temporal trend in the incidence of hospitalized toxic shock syndrome in women in the years 1977 through 1982 is consistent with the best available information on patterns of use of tampons containing higher-absorbency materials. The sharp increase in the incidence of hospitalized toxic shock syndrome in 1983 remains unexplained.

Adolescent↗
PubMed1986

Antibodies of predetermined specificity to the major charged species of human interleukin 1.

The development of highly specific antisera to human interleukin 1 (IL-1) has been an elusive goal hampered mainly by the availability of only limited amounts of pure immunogen. To surmount this difficulty, three peptides of the major charged species of IL-1 (pI 6.8) were synthesized and covalently coupled to keyhole limpet hemocyanin (KLH). All three peptide-KLH conjugates raised rabbit heterologous antisera that bound intact pure IL-1 in a dose-dependent and domain-specific manner. Immunoblot analysis of crude concentrated culture supernatants with these antisera showed each of them to be highly specific for mature 18-kDa IL-1. Immunoblot analysis of monocyte lysates revealed a single 33-kDa band consistent with the size of the IL-1 precursor molecule deduced from cloned cDNA. These reagents should prove to be valuable tools in the localization and measurement of IL-1 in cells and fluids and may permit the separate study of individual IL-1 species as well as discrete domains of intact IL-1 molecules.

Animals↗
PubMed1985

Sterol control of the phosphatidylethanolamine-phosphatidylcholine conversion in the yeast mutant GL7.

The relatively slow growth rate of the yeast mutant GL7, a sterol auxotroph, on medium containing cholesterol is markedly accelerated by supplementation with small amounts of ergosterol. Under these conditions (sterol synergism) cellular phospholipid synthesis is enhanced. We now find that one of the ergosterol-stimulated processes is the methylation of phosphatidylethanolamine to phosphatidylcholine. This is shown by comparing methyltransferase activities of membrane preparations derived from cells grown on either ergosterol, cholesterol, or the synergistic sterol pair. Incorporation of 32P from [gamma-32P]ATP into the yeast membranes is rapid and greater when ergosterol-grown cells rather than cholesterol-grown cells are the source of membranes.

Adenosine Triphosphate↗
PubMed1985

Identification and localization of human pancreatic tumor-associated antigens by monoclonal antibodies to RWP-1 and RWP-2 cells.

Human pancreatic adenocarcinoma cell lines, RWP-1 and RWP-2 (Dexter, D. L., Matook, G. M., Meitner, P. A., Bogaars, H. A., Jolly, G. A., Turner, M. D., and Calabresi, P. Cancer Res., 42: 2705-2714, 1982), were used as immunogens for the production of monoclonal antibodies to tumor-associated membrane antigens. BALB/c mice were immunized by i.p. injection of viable cells and hybridomas resulting from the fusion of splenocytes to myeloma cell line P3 X 63/Ag8.653 were screened by enzyme-linked immunosorbent assay for antibodies which reacted with both RWP-1 and RWP-2 cells. Hybridomas AR2-20 and AR1-28, both IgG1 antibody-producing cell lines, demonstrated membrane staining by immunofluorescence cytochemistry on three of seven pancreatic tumor cell lines but not on six human tumor cell lines of nonpancreatic origin, or on normal human fibroblasts. The antibodies stained frozen sections of RWP xenografts, propagated s.c. in nude mice, and tumor cells in paraffin sections of seven of seven cases of pancreatic ductal adenocarcinoma, using indirect immunofluorescence and immunoperoxidase histochemistry, but not normal adult or fetal pancreas, or a number of other normal adult tissues. Immunoprecipitation of 125I-labeled RWP-2 cells resulted in a single band with a molecular weight of 190,000 under reducing conditions. Sequential immunoprecipitation demonstrated that both AR2-20 and AR1-28 bind to the same molecule.

Animals↗
PubMed1985

Detection of human pancreatic adenocarcinomas by histochemical staining with monoclonal antibody AR1-28.

Hybridoma AR1-28 [Chin and Miller, Cancer Res 45:1723-1729, 1985] was produced using splenocytes from BALB/c mice which had been immunized with human pancreatic adenocarcinoma cell line RWP-1 [Dexter et al, Cancer Res 42:2705-2714, 1982]. This antibody cross reacted with the RWP-2 cell line. AR1-28, an IgG1 antibody, stained the membranes of five (RWP-1, RWP-2, BxPC-3, HPAF-2, and T3M4) out of ten human pancreatic tumor cell lines by immunofluorescence techniques. Electron microscopy on RWP-2 cells, stained by indirect immunoperoxidase, confirmed a membrane location for the AR1-28 antigen. Twenty-three of the 27 clinical specimens (83%) of formalin-fixed, paraffin-embedded pancreatic cancers tested were positive. Varying intensities of staining were observed and were related to the degree of differentiation achieved by the tumor: poorly differentiated tumors showing the least staining while well-differentiated tumors showed the greatest intensity of staining in a predominantly apical location. Immunoblotting showed that AR1-28 reacts with a 200,000-dalton antigen present in extracts of RWP-1 and RWP-2 cells. This monoclonal antibody may be useful in the classification of pancreatic tumor cells.

Adenocarcinoma↗
PubMed1985

Stimulation by unsaturated fatty acid of squalene uptake in rat liver microsomes.

Supernatant protein factor (SPF) and anionic phospholipids such as phosphatidylglycerol (PG) stimulate squalene epoxidase activity in rat liver microsomes by promoting [3H]squalene uptake as well as substrate translocation (Chin, J., and K. Bloch. 1984. J. Biol. Chem. 259: 11735-11738). This process is postulated to be membrane-mediated and not carrier-mediated. Here we show that treatment of PG with phospholipase A2 in the presence of bovine serum albumin abolishes the stimulatory effect of SPF on epoxidase activity. Disaturated fatty acyl-PGs are not as effective as egg yolk lecithin PG in the SPF effect. These findings suggest an important role for the unsaturated fatty acid moiety of PG. We also show that at submicellar concentrations, cis-unsaturated fatty acids stimulate microsomal epoxidase activity whereas saturated fatty acids do not. This effect is due to an increase in substrate uptake which in turn may facilitate substrate availability to the enzyme.

Animals↗
PubMed1984

Role of supernatant protein factor and anionic phospholipid in squalene uptake and conversion by microsomes.

Supernatant protein factor (SPF), a cytosolic protein (Mr = 47,000) stimulates microsomal squalene epoxidase activity 4- to 10-fold in the presence of anionic phospholipid such as phosphatidylglycerol (PG) (Saat, Y., and Bloch, K. (1976) J. Biol. Chem. 251, 5155-5160). This effect has been ascribed to substrate translocation from inactive to active pools within the membrane of the endoplasmic reticulum (Friedlander, E. J., Caras, I. W., Lin, L. F. H., and Bloch, K. (1980) J. Biol. Chem. 255, 8042-8045). Here we show that SPF and PG also stimulate squalene uptake per se by microsomes as well as stimulate squalene epoxidase. Microsomes preloaded with substrate in the presence of SPF and PG show full epoxidase activity. They do not require further addition of these factors during enzyme assay. Addition of SPF and PG to assay mixtures containing microsomes preloaded with substrate in the presence of SPF and PG did not further increase epoxidase activity. We also show that PG tightly binds to microsomes. This binding of PG is essential for the response of microsomal epoxidase to SPF. Solubilized microsomal enzymes have been reconstituted and show high epoxidase activity. In this system, SPF and PG do not stimulate the conversion of squalene into products.

Enzyme Activation↗
PubMed1984

Tetralogy of Fallot in the elderly.

Tetralogy of Fallot was first diagnosed during life in this patient at the age of 61 years. He represents one of the oldest reported patients with this congenital heart anomaly. This report presents a case of a previously undiagnosed patient with tetralogy of Fallot.

Cardiac Catheterization↗
PubMed1984

Specificity of a monoclonal antibody for the NH2-terminal region of fibrin.

A monoclonal antibody (MAb/T2G1s) was prepared by fusion using spleen cells from mice immunized with the NH2-terminal CNBr fragment of human fibrin II, the so-called (T)N-DSK [(A alpha 17-51, B beta 15-118, gamma 1-78)2]. In competition experiments, this antibody reacted with (T)N-DSK as well as peptide B beta 15-42 which can be obtained from (T)N-DSK by digestion with plasmin. Little or no reaction was observed with intact fibrinogen, the NH2-terminal CNBr fragments from fibrinogen (N-DSK) or fibrin I [(B)N-DSK], respectively, as well as peptide B beta 1-42. These results suggest that MAb/T2G1s is directed to an epitope on the B beta chain in fibrin II but not in fibrinogen or fibrin I. As such, MAb/T2G1s differs completely from another antibody (MAb/1-8C6)--also specific for the NH2-terminal region of the B beta chain--which was recently described [Kudryk et al. (1983) Molec. Immun. 20, 1191-1200].

Animals↗
PubMed1984

Monoclonal antibodies against SSEA-1 antigen: binding properties and inhibition of human natural killer cell activity against target cells bearing SSEA-1 antigen.

We describe the properties of three monoclonal antibodies (Mab) against stage-specific embryonic antigen-1 (SSEA-1) in terms of their binding activity to HL60, K562, OTF9, and SOTF9 tumor target cells and their functional activity in modulating human natural killer (NK) cytotoxicity assays in vitro against these target cells. Indirect binding, competition, and Western blot analyses indicate that the Mab AEC3A1-9 (3A1), ASSEA-1, and AECAB1-32 (AB1) recognize cell-defined SSEA-1 antigen with activity characteristic of the cell source (HL60 greater than OTF9 greater than K562 much greater than SOTF9). The addition of anti-SSEA-1 Mab to the NK cytotoxicity assay resulted in an inhibition of LU per 1 X 10(6) PBL that correlated closely with the expression of SSEA-1 antigen on the target cell. No significant inhibition was seen for seven other Mab. Inhibition of NK activity (greater than 30%) was observed in the presence of anti-SSEA-1 Mab for 18 of 21 and 6 of 7 human donors examined for HL60 and OTF9 target cells, respectively. The pretreatment of fixed competing cells with anti-SSEA-1 Mab reduced the efficacy of those cells to act as cold competitors in a standard NK cytotoxic assay. Taken together these data suggest that SSEA-1 determinants are important at some stage in the cytolysis produced by NK cells.

Animals↗