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J Xiang

Publications and source records attributed to J Xiang.

At least 127 records · Page 7Linked to original sources
PubMed1995

Expression of tumor-associated polymorphic epithelial mucin and carcinoembryonic antigen in gastrointestinal carcinoid tumors. Implications for immunodiagnosis and immunotherapy.

BACKGROUND: Gastrointestinal neoplastic epithelium of glandular origin commonly produces N-linked and O-linked glycoproteins such as carcinoembryonic antigen (CEA) and tumor-associated polymorphic epithelial mucin (PEM). Antibodies to these glycoproteins increasingly are being used in immunodiagnosis and/or immunotherapy. Although GI carcinoid tumors have a neuroendocrine immunophenotype and generally have an indolent clinical course compared with their adenocarcinomatous counterparts, they also arise from undifferentiated crypt epithelium. The purpose of this study was to determine whether GI carcinoids similarly expressed epitopes for CEA and PEM. METHODS: Thirty-nine GI carcinoid tumors from various topographic sites were analyzed by immunohistochemistry using the murine monoclonal antibodies B72.3, ACT19, and T84. The former two antibodies recognize epitopes in PEM, whereas the latter is an anti-CEA antibody, which was confirmed using enzyme-linked immunosorbent assays. RESULTS: The majority of carcinoid tumors (74%), particularly jejunoileal carcinoids, reacted for ACT19 antibody, whereas considerably fewer reacted for B72.3 (31%) and T84 (26%). The extent of staining was also greatest with ACT19. The GI mucosa adjacent to or overlying the carcinoid tumors also stained for the various antibodies. CONCLUSIONS: The extent and degree of positivity of carcinoid tumors for ACT19 raises the possibility that this antibody may be used in the future for the radioimmunodiagnosis and/or immunotherapy of these tumors, particularly in cases that are multicentric, unresectable, or with metastatic disease.

Animals↗
PubMed1995

Immunolocalization of hepatic metastases of human colonic cancer by chimeric anti-TAG72 antibody in SCID mice.

TAG72 is a well-characterized, human tumor-associated antigen present in > 85% of human colonic cancers. In this study, we established an animal model of hepatic metastases of human colonic carcinoma. The high-mucin variant cell line, designated HM7, was derived from the human colonic carcinoma cell line LS174T. Following intrasplenic injection, HM7 was able to induce much greater hepatic metastases in SCID mice compared to its parental cell line LS174T. Numerous hepatic metastases were evident 18 days subsequent to the intrasplenic injection of tumor cells. Using the chimeric anti-TAG72 antibody ccM4, immunohistochemistry demonstrated strong expressions of the TAG72 antigen in these metastases. Our biodistribution and imaging data also showed that the radiolabelled ccM4 antibody was able to localize hepatic metastases in the SCID mice. Based upon these findings, w anticipate that the herein described SCID mouse model will prove most useful in studying hepatic metastases of human colonic carcinoma by using anti-TAG72 therapeutic immunoreagents.

Adenocarcinoma↗
PubMed1995

The PITSLRE protein kinase family.

A family of p34Cdc2 related protein kinases, the PITSLRE kinases, is generated by alternative splicing and promoter utilization from three duplicated and tandemly linked genes on human chromosome 1p36.3, which is frequently deleted during the late stages of tumorigenesis. PITSLRE mRNA, protein, and enzyme activity are induced during Fas receptor- and glucocorticoid-mediated apoptosis of human T cells. Several PITSLRE isoforms are specific targets of proteolysis during apoptosis, generating an enzymatically active 50 kDa isoform. Inhibition of this protease activity blocks PITSLRE processing and enzyme activation, as well as apoptosis. Thus, PITSLRE kinases may be integral downstream components of apoptotic signal transduction pathway(s). Furthermore, PITSLRE genes, and their products, are physically altered in human neuroblastoma tumors, suggesting that they may be tumor suppressors.

Animals↗
PubMed1995

Autologous human B-cell immune response to pulmonary adenocarcinomatous polymorphic epithelial mucin.

In order to investigate whether a B-cell immune response to the polymorphic epithelial mucin (PEM) is present in adenocarcinomatous patients, peripheral blood lymphocytes from 20 patients with adenocarcinomas from various sites were fused with the mouse-human heteromyeloma cell line SHM-D33. One IgM(K) monoclonal antibody derived from peripheral blood lymphocytes of a patient with a lung adenocarcinoma was generated with binding reactivity for bovine submaxillary mucin (BSM). The latter is one of the PEMs, and it contains a large amount of the tumor-associated sialosyl-Tn epitope. The generated antibody was designated KMD-2. Immunohistological studies on various tissues showed that KMD-2 reacted with 6/6 colorectal adenocarcinomas and 4/6 pulmonary adenocarcinomas. The antibody also displayed a slight degree of cross-reactivity with a limited number of normal tissues, especially those that elaborate mucin. Our data show that an autologous antibody response in the form of IgM to the immunosuppressive PEM is present in some adenocarcinomatous patients. The data also suggest that the KMD-2 (IgM/K) antibody may be of clinical importance for diagnostic purposes of adenocarcinomatous disease.

Adenocarcinoma↗
PubMed1995

Antibody-targeted lymphokine-activated killer cells inhibit liver micrometastases in severe combined immunodeficient mice.

BACKGROUND & AIMS: Animal models for hepatic metastases can facilitate the investigation of lymphokine-activated killer (LAK) cell-based immunotherapy. The aim of this study was to investigate the efficacy of ccM4 antibody-targeted LAK cells in inhibiting hepatic micrometastases. METHODS: Hepatic micrometastases were generated after the intrasplenic injection of HM7 colon carcinoma cells. TAG72 expression was detected in these hepatic micrometastases using ccM4 antibody. The ccM4 antibody was conjugated onto LAK cells by treatment with 17.5% polyethylene glycol 8000. After the intrasplenic injection of HM7 cells, severe combined immunodeficient mice were randomized into five groups (i-v) and received either 10(7) ccM4-LAK cells plus 1000 U interleukin 2 (IL-2; group i), LAK cells plus 50 micrograms ccM4 and IL-2 (group ii), LAK cells plus IL-2 (group iii), IL-2 alone (group iv), or only phosphate-buffered saline (group v). RESULTS: The ccM4-LAK cells retained cytolytic activity and acquired TAG72-binding reactivity. The results showed that group i had significantly fewer hepatic metastases compared with group ii or group iii (P < 0.05) and even fewer hepatic metastases compared with group iv or group v (P < 0.001). CONCLUSIONS: These results show that ccM4 antibody-targeted LAK cells significantly inhibited tumor growth in vivo; thus, they can be potentially useful in treatment of hepatic micrometastases.

Animals↗
PubMed1995

A genetically engineered single-chain FV/TNF molecule possesses the anti-tumor immunoreactivity of FV as well as the cytotoxic activity of tumor necrosis factor.

Recombinant DNA techniques were used to clone, construct and express the fused gene FV-TNF in E. coli under control of the strong T7 bacteriophage promoter in the expression vector pT7-7-FV-TNF. The fusion protein FV/TNF in inclusion bodies from the bacteria homogenate was solubilized in the denaturing solution containing 6 mol/l guanidine and 0.3 mol/l DTT and refolded in refolding buffer containing 8 mmol/l GSSG. The FV/TNF was purified by ion exchange chromatography. The yield of FV/TNF was estimated at 10 mg/l. The purified FV/TNF displayed a single band of 42 kD under reducing conditions, whereas it showed three forms including its monomer (40/42 kD), its dimer (84 kD) and its trimer (126 kD) under non-reducing conditions. Our data showed that this fusion protein retained its bifunctional activities well, namely the anti-TAG72 immunoreactivity of the FV portion and the cytotoxic activity of the TNF moiety. Therefore, the FV/TNF fusion protein may prove useful in targeting the biological effect of TNF to tumor cells as well as in stimulating the immune destruction of tumor cells.

Adenocarcinoma↗
PubMed1995

Choroid plexus potassium cotransport: modulation by osmotic stress and external potassium.

The choroid plexuses are involved in CSF secretion and CSF K homeostasis. This study examines the potential role of K cotransport in these two processes using isolated rat lateral ventricle choroid plexuses. Bumetanide-sensitive 86Rb influx and efflux were measured to assess the response of K cotransport to changes in media osmolality and K concentration. Alterations in osmolality had no effect on K uptake (in the presence or absence of bumetanide). However, the efflux rate constant for K was 0.29 +/- 0.02, 0.44 +/- 0.04, and 0.84 +/- 0.06 min-1 in 240, 300, and 424 mOsm/kg solutions, respectively (p < 0.001). This increase in efflux with osmolality, an opposite effect to that found in many cells, was solely due to enhanced K cotransport. The increased cotransport may be involved in limiting brain shrinkage during hyperosmotic stress if the cotransporter is present on the apical membrane. The rate of bumetanide-sensitive efflux was unaffected by changes in external [K]. However, the rate of K uptake (measured on return to normal [K] media) was reduced gradually by exposure to low [K]. It was 21 +/- 1, 19 +/- 3, 13 +/- 2, and 6 +/- 1 nmol/mg/min after 0, 10, 30, and 60-min exposure to 1 mM K. Sixty minutes of exposure to 1 mM [K] abolished the bumetanide-sensitive K uptake present in plexuses exposed continually to normal media. This modulation of K cotransport by external [K] may be important in CSF K homeostasis by limiting K loss from the CSF if CSF [K] is low.

Animals↗
PubMed1995

N-system amino acid transport at the blood--CSF barrier.

Despite L-glutamine being the most abundant amino acid in CSF, the mechanisms of its transport at the choroid plexus have not been fully elucidated. This study examines the role of L-, A-, ASC-, and N-system amino acid transporters in L-[14C]glutamine uptake into isolated rat choroid plexus. In the absence of competing amino acids, approximately half the glutamine uptake was via a Na(+)-dependent mechanism. The Na(+)-independent uptake was inhibited by 2-amino-2-norbornane carboxylic acid, indicating that it is probably via an L-system transporter. Na(+)-dependent uptake was inhibited neither by the A-system substrate alpha-(methylamino)isobutyric acid nor by the ASC-system substrate cysteine. It was inhibited by histidine, asparagine, and L-glutamate gamma-hydroxamate, three N-system substrates. Replacement of Na+ with Li+ had little effect on uptake, another feature of N-system amino acid transport. These data therefore indicate that N-system amino acid transport is present at the choroid plexus. The Vmax and Km for glutamine transport by this system were 8.1 +/- 0.3 nmol/mg/min and 3.3 +/- 0.4 mM, respectively. This system may play an important role in the control of CSF glutamine, particularly when the CSF glutamine level is elevated as in hepatic encephalopathy.

Amino Acids↗
PubMed1995

PITSLRE protein kinase activity is associated with apoptosis.

Minimal ectopic expression of a 58-kDa protein kinase (PITSLRE beta 1), distantly related to members of the cdc2 gene family, induces telophase delay, abnormal chromosome segregation, and decreased growth rates in Chinese hamster ovary cells. Here we show that this decrease in cell growth rate is due to apoptosis. Apoptosis is also induced by ectopic expression of an amino-terminal deletion mutant containing the catalytic and C-terminal domains of PITSLRE beta 1 but not by other mutants lacking histone H1 kinase activity or by other members of the cdc2 gene family. However, unlike the wild-type PITSLRE beta 1 over-expressors, ectopic expression of the N-terminal PITSLRE beta 1 mutant does not result in telophase delay or abnormal chromosome segregation. These results suggested that the function of this protein kinase could be linked to apoptotic signaling. To test this hypothesis, we examined levels of PITSLRE mRNA, steady-state protein, and enzyme activity in human T cells undergoing apoptosis after activation with the anti-Fas monoclonal antibody (MAb). All were substantially elevated shortly after Fas MAb treatment. In addition to new transcription and translation, proteolysis contributed to the increased steady-state levels of a novel 50-kDa PITSLRE protein, as suggested by the diminution of larger PITSLRE isoforms observed in the same cells. Indeed, treatment of the Fas-activated T cells with a serine protease inhibitor prevented apoptotic death and led to the accumulation of larger, less active PITSLRE kinase isoforms but not the enzymatically active 50-kDa PITSLRE isoform. Finally, induction of apoptosis by glucocorticoids in the same cell line, as well as by Fas MAb treatment of another T-cell line, led to a similar induction of 50-kDa PITSLRE protein levels over time. These findings suggest that (i) PITSLRE kinase(s) may lie within apoptotic signaling pathway(s), (ii) serine protease activation may be an early event in Fas-activated apoptosis of human T cells, and (iii) some PITSLRE kinase isoforms may be targets of apoptotic proteases.

Amino Acid Sequence↗
PubMed1995

[Physiological and clinical observation of nasal valve].

In order to explore the site of the nasal valve, the changes of nasal airway resistance (NAR) were measured in normal adults, the patients with chronic rhinitis and the patients undergoing partial inferior turbinotomy by placing plastic pipes with various diameters in the ostium internum. The results showed that before the nasal mucosa decongested, the NAR significantly reduced with the increase of pipe's diameter at the beginning of the test. NAR stopped reducing when the diameter of the pipe increased to some extent. After the nasal mucosa decongested, NAR reduced with the increase of the diameter of the pipes. It suggested that the site of nasal valve is changeable and related to the state of contraction and relaxation of the nasal mucosa and the extent of nasal patency.

Adolescent↗
PubMed1995

A genetically engineered fusion protein M4/TNF with increased bifunctional activity refolded in the presence of protein disulfide isomerase.

Recombinant DNA techniques were used to clone, to construct and to express a fusion protein M4/TNF in Escherichia coli. The fusion protein includes the chimeric F(ab')2 fragment (M4) recognizing the human tumor-associated TAG72 antigen and the tumor necrosis factor alpha (TNF) moiety. The M4/TNF purified from inclusion bodies of the bacteria homogenates was further solubilized in a denaturing buffer containing 6 mol l-1 guanidine and refolded in a refolding buffer. Our results showed that the M4/TNF refolded in a buffer containing 6 mmol l-1 oxidized glutathione (GSSG), 0.2 mmol l-1 dithioerythione (DTE) and 0.5 mumol l-1 protein disulfide isomerase (PDI) displayed a 4-fold higher anti-TAG72 immunoreactivity and a 5-fold higher TNF activity than that refolded in the same refolding buffer but without PDI. Our data thus indicates that the protein disulfide isomerase not only facilitates the correct formation of disulfide-bonds of the antibody molecule, but also the correct refolding of the TNF moiety in vitro.

Amino Acid Sequence↗
PubMed1995

A genetically engineered single-gene-encoded anti-TAG72 chimeric antibody secreted from myeloma cells.

SP2/0Ag14 murine myeloma cells transfected with the expression vector mpSV2neo-EP-FV-CH2-3-PA containing the single gene FV-CH2-3 secreted a single-gene-encoded chimeric antibody molecule FV/M4. This single-chain protein consisted of the heavy- and light-chain variable (VH and VL) domains covalently joined through a flexible linker peptide, while the carboxyl end of VL domain was connected to the amino terminus of hinge region of the ccM4 heavy-chain. Our data showed that the FV/M4 retained both its immunoreactivity for tumor-associated TAG72 antigen and its cytolytic activity to tumor cells as did the parental ccM4 antibody. Therefore, this single-gene-construct approach circumvents inefficiencies inherent in delivering two genes into a mammalian cell for assembly of a functional chimeric antibody and provides an alternative for construction of chimeric antibodies. It is particularly attractive for ex vivo transfection of cells from patients for certain gene-therapy modalities not only for cancer but also for a range of diseases in which immunotherapeutic approaches are used.

Amino Acid Sequence↗
PubMed1995

[Statistical analysis of 4,547 burn patients and the mortality in different periods].

4,547 burn patients from 1983-1993 were reviewed by analysing the general data, mortality, and the causes of the death, and the mortality of 606 burn patients in different periods from 1958 to 1993. The purpose was to present some statistical and epidemiological data. The results showed: The incidence of burn injury in children, whose ages were less than 5 years, reached 36.2%, and the causes of burn was mainly thermal injury. The total mortality was 3.2%, and the main cause of the death was burn wound sepsis. No significant difference in the relationship between the mortality and the burn wound area was observed in these burn patients. In different age groups, the size of III degree burn, which accounted for higher mortality, was much different. The incidence of burn wound sepsis, which was the main cause of mortality, was on the increase, as the analysis of 606 burn patients in four different periods from 1958-1963 showed. In regard to the cure rate, the improvement had not been obvious since 1983.

Adolescent↗
PubMed1995

[Cryosurgical resection of pulmonary metastases (experience of twenty years)].

Cryosurgical resection of pulmonary metastases was performed in 112 patients from 1973 to 1993. The cumulative 1, 3, 5, 10 year survival rate was 80.37%, 41.81%, 28.01% and 17.28%. One patient died of respiratory failure after operation. Thirty-day mortality rate was 0.89%. The disease-free interval (DFI) between the control of primary tumor and appearance of metastases was significantly correlated with post-thoracotomy survival. The multiple factor analysis also demonstrated that DFI was the most important prognostic factor for patients after cryosurgical resection of pulmonary metastatic lesions. The overall 5 year survival rate of patients treated with cryosurgery in our report was higher than that of those treated by local resection of pulmonary metastases reported by other authors. Our results indicated that cryosurgical resection of pulmonary metastases was effective and safe, the survival time of most patients could be prolonged and some patients could be cured.

Adult↗
PubMed1994

Cloning and expression of functional cDNA genes of a mouse/human chimeric antibody rcM4.

AIM: The purpose of this study was to clone and express cDNA genes of heavy and light chains of the mouse/human chimeric antibody rcM4, which recognize the sialosyl-Tn epitope of the TAG72 antigen. METHODS: The cDNA genes of chimeric heavy-chain M4H2 and light-chain M4K4 were cloned from the cDNA library of the ccM4 transfectoma. The M4H2 and M4K4 genes were modified in polymerase chain reaction and ligated into mpSV2neo-EP-PA and mpSVgpt-EP-PA to form the heavy- and the light-chain expression vectors mpSV2neo-EP-M4H2-PA and mpSV2gpt-EP-M4K4-PA, respectively. These two expression vectors were then co-transfected into the myeloma cell line SP2/0Ag14. Transfectants were selected in media containing G418 and mycophenolic acid. The rcM4 antibody was purified from transfectant culture supernates by protein A affinity chromatography. RESULTS: The yield of the recombinant chimeric antibody rcM4 from its culture supernates was 6 micrograms/ml. We demonstrated that the rcM4 antibody retained its binding reactivity for sialosyl-Tn and that it was able to mediate effective antibody-dependent cellular cytotoxicity to the human ovarian cancer cell line OVCAR 3 in a manner comparable to the original ccM4 antibody. CONCLUSION: The cDNA genes of chimeric heavy-chains (M4H2) and light-chains (M4K4) could be functionally expressed in the SP2/0Ag14 myeloma cell line. They thus have potential utility in the construction of some novel hybrid proteins such as those containing both antitumor immunoglobulins and cytokine molecules for use in cancer immunotherapy.

Amino Acid Sequence↗
PubMed1994

Molecular cloning and expression of alternatively spliced PITSLRE protein kinase isoforms.

Minimal ectopic expression of the p58GTA protein kinase results in a provocative phenotype involving cell cycle delay, mitotic catastrophe, and decreased cell viability. In addition, this kinase is well conserved evolutionarily, ubiquitously expressed, and its genes map to a position on human chromosome 1 frequently deleted in the late stages of tumorigenesis. Here we report that the p58GTA protein kinase is a member of a larger subfamily of proteins. The mRNAs encoding these proteins are generated by alternative splicing from multiple duplicated genes. These isoforms range in size from 50 to 110 kDa. Divergence between the alternatively spliced isoforms is localized to the amino-terminal region of the molecule. The entire p58GTA open reading frame is conserved in most of these p58GTA isoforms. The predicted sequences of the larger isoforms encode bipartite nuclear localization signal sequences and extensive polyglutamic acid domains. Antibodies to the p58GTA isoform were used to confirm the presence of the alternatively spliced isoforms in different cell types as well as identify two additional isoforms that appear to arise from a separate gene(s). Cellular fractionation studies indicate that one of the isoforms is found only in the nucleus, and the remainder are found in both the cytoplasm and the nucleus. Expression and localization of some p58GTA isoforms suggest that they may have specialized cellular functions. Because of the large number of isoforms generated from multiple genes we propose naming these kinases PITSLRE alpha 1, alpha 2-1, alpha 2-2, alpha 2-3 alpha 2-4, beta 1, beta 2-1, and beta 2-2 based on the conserved sequence of the PSTAIRE box unique to p34cdc2 kinases and the gene from which they are transcribed.

Alternative Splicing↗
PubMed1994

2-Aminopurine overrides a late telophase delay created by ectopic expression of the PITSLRE beta 1 protein kinase.

Minimal overexpression of the PITSLRE beta 1 protein kinase in CHO cells leads to a marked delay in late mitosis. We have previously shown that this delay is characterized by the presence of substantially increased numbers of tubulin midbodies, inhibition of cytokinesis, and numerous multinucleated and micronucleated cells. Others have shown that the protein kinase inhibitor 2-aminopurine (2-AP) is capable of overriding drug induced cell cycle blocks. In this study we demonstrate that the late mitotic delay and altered cellular morphology caused by ectopic expression of the PITSLRE beta 1 protein kinase can be overcome by 2-aminopurine treatment. Furthermore, 2-aminopurine inhibits PITSLRE beta 1 protein kinase activity in vivo, but does not effect p34cdc2 protein kinase activity in a similar manner.

2-Aminopurine↗