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Biomedical subjects

N N Teng

Publications and source records attributed to N N Teng.

At least 19 recordsLinked to original sources
PubMed1997

Cytotoxicity of murine B lymphocytes induced by human VH4-34 (VH4.21) gene-encoded monoclonal antibodies.

We have previously described specific binding and cytotoxicity of human B lymphocytes by VH4-34 gene-derived anti-i cold agglutinin (CA) mAbs. Here we demonstrate that the carbohydrate ligand recognized by human VH4-34 anti-i CA mAbs is also expressed on murine B lymphocytes. Similar to human B cells, binding of murine B lymphocytes by VH4-34-derived anti-i CA mAbs leads to rapid cytotoxicity of target cells as tested both in vitro and in vivo. Moreover, the mechanism leading to murine B cell death is also similar to human B cells, since morphologically identical membrane pores were detected within 15 min of mAb exposure by scanning electron microscopy. The conservation of the carbohydrate ligand across species provides an ideal system to study the function of human VH4-34 gene derived Abs in immune regulation.

Animals↗
PubMed1997

Rapid cytotoxicity of human B lymphocytes induced by VH4-34 (VH4.21) gene-encoded monoclonal antibodies, II.

We have previously described complement-independent killing of human B lymphocytes by two IgM MoAbs derived from the VH4-34 (VH4.21) gene. Analysis of 17 independently derived VH4-34-encoded MoAbs shows that B cell toxicity is not limited to the two described MoAbs, but is a general property shared by a subset of MoAbs derived from the VH4-34 gene. As observed by two independent microscopy techniques, giant membrane pores were formed on target B cells within 10-15 min of exposure to cytotoxic VH4-34-derived MoAbs. Toxicity by individual MoAb correlated directly to its B cell binding intensity measured by FACS, i.e. stronger the binding greater the killing. Sequence analysis showed that V(H) region in germ-line or in near germ-line configuration was necessary but not sufficient for B cell binding. In addition, a particular sequence motif enriched in basic amino acids in the CDR3 may be required to supplement the reactivity mediated by the V(H) region of the MoAb molecule. VH4-34-encoded antibodies that fulfil the above sequence requirements have cold agglutinin activity towards the i antigen of cord erythrocytes. In vivo, such anti-i/anti-B cell antibodies are rarely detected in healthy adults, but serum levels are dramatically elevated in selective pathological conditions, such as systemic lupus erythematosus and infectious mononucleosis. This strict regulation may be related to the novel and rapid mechanism of human B cell toxicity demonstrated by antibodies encoded by a single human V(H) gene.

Adult↗
PubMed1996

Lymphangioleiomyomatosis of the uterus simulating high-stage endometrial stromal sarcoma.

Symptomatic uterine lymphangioleiomyomatosis (LAM) simulating high-stage uterine sarcoma in a patient with tuberous sclerosis complex is reported. A 49-year-old female presented with abdominal pain and anemia. Preoperative workup revealed a uterine mass and a large amount of peritoneal free fluid and possible metastatic implant along the lateral edge of the liver. The patient also had a large right pleural effusion. A fungating anterior uterine fundal mass with apparent perforation and intraabdominal hemorrhage was found on laparotomy. A portion of the mass was excised and initially interpreted as an endometrial stromal sarcoma. Microscopic examination revealed multiple vascular epithelioid smooth muscle proliferations in the uterus and serosal surface of the fallopian tube and periaortic lymph node lymphangioleiomyomas. The uterine, fallopian tube, and nodal lesions were positive for smooth muscle actin, desmin, and HMB-45, findings characteristic of LAM. Additional examination of the patient revealed stigmata of tuberous sclerosis complex. Although uterine LAM is uncommon, it may be associated with pelvic and/or abdominal symptoms and may simulate a primary uterine mesenchymal neoplasm.

Diagnosis, Differential↗
PubMed1996

Rapid cytotoxicity of human B lymphocytes induced by VH4-34 (VH4.21) gene-encoded monoclonal antibodies.

We have previously described two human cold agglutinin MoAbs 216 and A6(H4C5), that are derived from the VH4-34 (VH4.21) gene that bind specifically to a cell surface ligand on human B lymphocytes. In this study, we report that binding of 216 and A6(H4C5) leads to rapid killing of target B cells. This complement-independent cytotoxicity was measured by three independent assays, cell viability dye uptake on FACS, 3H-thymidine uptake, and the 3(4,5)-dimethylthiazol-2,5-diphenyl tetrazolium bromide (MTT) assay. Cytotoxicity was specific for CD20+ mononuclear cells in human spleen and peripheral blood. The MoAbs were also cytotoxic to human B cell lines Nalm-6, OCI-LY8, Arent and SUP-B8, but not to T cell lines HuT 78 and PEER. As observed by scanning electron microscopy, membrane pores were formed within 15 min of exposure to the MoAbs. Cytotoxic activity was dependent on MoAb concentration and temperature of exposure. Killing with greater at 4 degrees C than 37 degrees C. Sodium azide and EDTA did not block the cytotoxic activity. No DNA fragmentation typical of apoptosis was observed. This rapid cytotoxic activity, independent of physiologic cellular process and independent of complement, suggests a novel mechanism of all death via membrane perturbations.

Antibodies, Monoclonal↗
PubMed1996

Operative laparoscopy in the management of ovarian cancer.

Advances in operative laparoscopic techniques have made possible the extension of this technology to the treatment of women with ovarian cancer. We present a detailed case series of eight patients with ovarian cancer who underwent a total of 11 operative laparoscopies for treatment of ovarian cancer ranging in stage from IA to IIIC. Three patients underwent initial laparoscopic staging and therapeutic debulking procedures. In three other cases that were incompletely staged via laparotomy, laparoscopy was used to complete the staging. Interval laparoscopic tumor debulking combined with second-look laparoscopy was performed in four cases. We describe our experience with these new applications of evolving techniques with particular regard to potential advantages, disadvantages, and complications. This detailed preliminary case series suggests the need for prospective clinical studies to establish the safety and efficacy of the approach.

Adult↗
PubMed1996

VH4-34 (VH4.21) gene expression in the chronic arthritides of childhood: studies of associations with anti-lipid A antibodies, HLA antigens, and clinical features.

OBJECTIVE: To determine if the germ line gene VH4-34 (VH4.21) encodes the antimonophosphoryl lipid A (MPL) polyspecific antibodies found in oligoarticular arthritis of childhood. METHODS: Sera from a range of rheumatic diseases of childhood were assayed for VH4-34 derived antibodies by ELISA using the antiidiotype monoclonal antibody 9G4. Results were compared to assays for anti-MPL antibodies, C4d, and Bb, and for HLA type, joint count, and sedimentation rate. RESULTS: VH4-34 derived antibodies were elevated in all diseases studied except rheumatoid factor positive polyarticular disease. In oligoarticular arthritis, VH4-34 gene expression correlated with C4d concentration, and VH4-34 encoded globulins were more concentrated in synovial fluid than in blood. No association was found with HLA type. An association between VH4-34 expression and IgG anti-MPL was found in sera from patients from Cincinnati but not from Stanford. No other evidence supported a direct association between VH4-34 derived and anti-MPL antibodies in these children. CONCLUSION: The expression of VH4-34 is increased in several rheumatic diseases of childhood, but, as in adults, not in rheumatoid arthritis. VH4-34 expression is not associated with HLA type. The polyspecific autoantibody nature of some VH4-34 derived antibodies may explain the wide range of the unusual antibodies found in oligoarticular arthritis.

Antibodies↗
PubMed1995

Human CD5+ B lymphocytes (B-1 cells) decrease in peripheral blood during pregnancy.

Pregnancy is a unique immunologic state where a natural homeostasis exists between antigenically different tissues. Several earlier studies have addressed the fluctuations in the number and/or function of lymphocytes, including B cells during pregnancy, but changes within the subsets of B lymphocytes, conventional (CD5-) and B-1 (CD5+), have not been addressed. Here we demonstrate that the frequency of B-1 cells decreases dramatically during pregnancy, whereas the frequency of conventional B cells remains relatively constant. The missing B-1 cells return to pre-pregnancy levels 8-10 weeks after parturition. The polyreactive autoantibodies secreted by B-1 cells have been implicated in autoimmunity and immune regulation. The possible role of B-1 cells during pregnancy will be discussed in that context.

Adult↗
PubMed1995

Anti-endotoxin human monoclonal antibody A6H4C5 (HA-1A) utilizes the VH4.21 gene.

Human IgM monoclonal antibody A6H4C5 was manufactured by Centocor (Malvern, PA) and used in clinical trials as HA-1A (Centoxin). In vitro, A6H4C6 binds to lipid A and rough-strain, gram-negative bacteria endotoxin. Further analysis of A6H4C5 has shown that it is a polyreactive, cold agglutinin that utilizes the VH4.21 gene segment in germline configuration. It is also a human antibody that binds to human B cells. We have characterized several other independently derived VH4.21 human monoclonal antibodies with the same characteristics as A6H4C5. This group of antibodies may represent a conserved host immune response.

Agglutinins↗
PubMed1994

FACS analysis of peritoneal lymphocytes in ovarian cancer and control patients.

In this study different lymphocyte populations in the malignant ascites of 10 patients with ovarian carcinoma and in the peritoneal fluid of 8 control patients (tubal ligation and benign conditions) were analyzed. A panel of monoclonal antibodies against the CD markers of lymphocytes was used to stain different populations and the cells were analyzed on a FACS II (fluorescence-activated cell sorter). The mean percentage of B lymphocytes in the peritoneal cavity of the OVCA patients was 0.18 +/- 0.5% and in the control patients 0.05 +/- 0.07%. There was no significant difference between the two groups. In the OVCA group and in the controls the percentage of T lymphocytes (CD5+) was 23.5% and 17.1% respectively with no significant difference between the groups. These results indicate that B lymphocytes are not present in the human peritoneal cavity. The small numbers of B cells found in this study could be due to contamination with peripheral blood. The human peritoneal cavity contains a cell population which differs from that present in peripheral blood. Significant numbers of B lymphocytes have been reported in the peritoneal cavity of mice. The difference between the lymphocyte population of the human peritoneal cavity and that of rodents implies that data on characterization and function of B lymphocytes in the mouse peritoneal cavity would not be applicable to humans.

Ascitic Fluid↗
PubMed1993

Human antilipid A monoclonal antibodies bind to human B cells and the i antigen on cord red blood cells.

We describe two independently derived human mAb, A6(H4C5) and 216, initially selected for their reactivity to the lipid A domain of bacterial LPS, which also react with the following Ag: the i Ag present on cord RBC, a ligand on human B lymphocytes, and to certain autoantigens, defining these mAb as polyreactive. Both mAb have specific affinity for a carbohydrate epitope consisting minimally of a disaccharide with an acyl substitution at the 2-carbon position. Structural examination of the diverse Ag recognized by the two antibodies reveals the presence of this carbohydrate structure required for antibody binding. A6(H4C5) and 216 are IgM in isotype, but differ in their L chain expression. Molecular analysis shows that both the mAb are encoded by a highly conserved VH4 gene, designated VH4-21. This gene encodes a number of autoantibodies, particularly cold agglutinins. Specific recognition of lipid A and of a carbohydrate epitope on B lymphocytes by the two human mAb suggests a dual function for the highly conserved VH4-21 gene in antibacterial response and in B cell development and regulation.

Agglutinins↗
PubMed1993

Long-term survival with adjuvant whole abdominopelvic irradiation for uterine papillary serous carcinoma.

BACKGROUND: The optimum management of uterine papillary serous carcinoma (UPSC), a clinically aggressive histologic variant of endometrial adenocarcinoma, is a controversial issue. METHODS: Ten patients with UPSC were reviewed who received whole abdominopelvic irradiation (WAP) as adjuvant therapy after a staging laparotomy and debulking surgery. RESULTS: Nine patients had clinical Stage I disease; the tumors in eight of them were upstaged based on laparotomy findings. There was greater than a 50% invasion of the myometrium in four of the hysterectomy specimens, and vascular space invasion was noted in seven patients. Peritoneal washings were positive in three of the nine specimens obtained; two others showed atypical cells. Five patients are alive with no evidence of disease at 102-133 months. Four patients are dead, and one patient is alive with disease. All recurrences were observed within 30 months of the initial diagnosis and were more common in the presence of deep myometrial invasion and vascular space involvement. Three of the four patients who died had pleural effusions that did not respond to hormonal and/or chemotherapy. Local irradiation produced long-term control of recurrences in two patients, including one with supraclavicular lymph node metastases who had no evidence of disease 117 months after radiation treatment to the involved nodes. CONCLUSIONS: These findings suggest that WAP be considered as an adjuvant therapy in the management of UPSC. The patients with the greatest benefit were those with early disease by surgical staging with or without positive peritoneal cytologic findings. For patients at high risk for pleural effusions and pulmonary metastasis, additional adjuvant therapy, such as innovative chemotherapy or low-dose lung irradiation, needs to be considered.

Adenocarcinoma↗
PubMed1993

Peritoneal implant elimination during cytoreductive surgery for ovarian cancer: impact on survival.

A case-control study was performed to evaluate the potential benefit of peritoneal and serosal implant elimination (PIE) during primary cytoreductive surgery for patients with Stage IIIC epithelial ovarian cancer. Peritoneal implant excision and/or ablation was accomplished with electrocautery, CO2 laser, sharp dissection, argon beam coagulator, and cavitron ultrasonic surgical aspirator. Three groups of patients were compared: Group A (7 patients); macroscopically disease-free after cytoreduction without needing PIE; Group B (26 patients); macroscopically disease-free after cytoreduction, including PIE; Group C (34 patients); macroscopic disease < or = 1 cm remaining exclusively on peritoneal surfaces with PIE not attempted. Each group had statistically equivalent mean ages, estimated blood loss, extent of disease, and variety of cytoreductive operations performed. Group B had a longer mean operating time than that of A or C (4.0 vs 2.8 hr P = 0.002). No serious morbidity occurred from PIE. Comparison of survival by log rank analysis and Cox proportional hazards regression shows a survival advantage for patients rendered free of macroscopic peritoneal implants (Group B vs Group C; P = 0.003). The result suggests that complete elimination of all visible peritoneal metastases might be of benefit during surgical cytoreduction for ovarian cancer if this renders the patient macroscopically disease-free. We also suggest the need of a randomized, prospective study to clarify the clinical role of PIE.

Case-Control Studies↗
PubMed1993

Documentation of complete resolution of gestational choriocarcinoma in the oophorectomized patient.

A 39-year-old woman with choriocarcinoma metastatic to the lungs and parametrium underwent total abdominal hysterectomy/bilateral salpingo-oophorectomy and follow-up chemotherapy with regression of the hCG assay, plateauing at 9 mIU/ml. Spinal fluid hCG assay was negative. An LH assay was performed which was 135 mIU/ml (2nd IRP-HMG). A quantitative hCG assay was performed on two sources of purified LH at varying concentrations to determine the contribution of LH cross-reactivity. When corrected for the LH contribution, the quantitative hCG was zero. Chemotherapy was discontinued. At 12-months follow-up the patient has remained in complete chemical remission and has an excellent performance status. Whenever a patient is oophorectomized, LH cross-reactivity should be ruled out as a cause for persistent low titers of hCG.

Adult↗
PubMed1993

Lipopolysaccharide and peptidoglycan share binding sites on human peripheral blood monocytes.

p73, a binding site for lipopolysaccharide (LPS) on human peripheral blood monocytes was identified using the radiolabeled photoaffinity cross-linker sulfosuccinimidyl 2-(p-azidosalicylamido)ethyl-1,3'-dithiopropionate (SASD). The 125I-labeled conjugate of SASD and LPS (125I-labeled ASD-LPS) was bound to monocytes and UV cross-linked, and the cellular extracts were analyzed with two-dimensional SDS-PAGE and autoradiography. In addition to the major binding site on human monocytes at 73 kDa, isoelectric point 5.95, there were multiple minor binding sites that recognized both smooth and rough LPS. Binding of 125I-labeled ASD-LPS to monocytes is concentration dependent, decreased in the absence of calcium and magnesium, and inhibited by either excess LPS or the low-molecular-weight soluble isolate of bacterial cell wall peptidoglycan (sPGN). However, sPGN only minimally stimulates tumor necrosis factor (TNF) secretion by human peripheral blood mononuclear cells. In contrast, the relatively insoluble high-molecular-weight peptidoglycan significantly stimulates TNF secretion.

Azides↗
PubMed1992

Critical reassessment of second-look exploratory laparotomy for epithelial ovarian carcinoma. Minimal diagnostic and therapeutic value in patients with persistent cancer.

From 1979 to 1984, 88 women with epithelial ovarian cancer were treated with surgery and chemotherapy, achieved a clinical complete response, and then had "second-look" exploratory laparotomy to assess the pathologic status of their disease. Persistent cancer was found in 50 (57%) patients: 34 of 50 (68%) had gross tumor, which was larger than 2 cm in 12 (24%) and smaller than 2 cm in 22 (44%), and 16 (32%) had microscopic disease. Salvage therapy was as follows for these patients: whole abdominal irradiation, 29 (58%); chemotherapy, 17 (34%); intraperitoneal chromic phosphate, 1 (2%); and no further therapy, 3 (6%). With a follow-up time of 4 to 8 years, 7 (14%) patients are alive without evidence of cancer, 7 (14%) are alive with disease, 35 (70%) are dead of disease, and 1 (2%) has died of treatment complications. At 5 years, the relapse-free rate was 18% and the survival rate was 25%. Seventy-two parameters of suspected prognostic significance and 64 potential sites of tumor involvement were correlated with survival in a univariate analysis. The factors favorably affecting survival included the following: lower grade; microscopic tumor versus gross disease at second-look laparotomy; removal of the uterus; removal of the omentum; pelvic and paraaortic lymph node biopsy; negative results of a right diaphragm biopsy; and radiation therapy at Stanford University Medical Center, Stanford, California. There was no survival advantage for whole abdomen irradiation compared with chemotherapy or for the patients who had their disease successfully debulked at second-look laparotomy. The above factors and others were evaluated by multivariate regression. The best model (P = 0.000004) for predicting survival included largest tumor mass (P = 0.0002), operative blood loss (P = 0.002), perioperative blood transfusion (P = 0.003), and grade (P = 0.004). The detection of persistent ovarian cancer by second-look exploratory laparotomy should identify a subgroup of patients whose conditions can be salvaged by a second-line therapy. Unfortunately, that subgroup is small (8%) and an effective salvage therapy remains to be identified.

Combined Modality Therapy↗
PubMed1992

Human monoclonal antibody recognizing an antigen associated with ovarian and other adenocarcinomas.

MS2B6, a human monoclonal antibody derived from a patient with advanced ovarian cancer, has been used to study the distribution and characteristics of its target antigen. The MS2B6 antigen was detected by immunoperoxidase studies in 41 of 41 epithelial ovarian cancers and in the majority of nonovarian adenocarcinomas. Among normal tissues the MS2B6 antigen was found in the adult epithelia of the fallopian tube, endometrium, endocervix, colon, bronchus, breast, sweat duct, and large renal ducts. No detectable antigen was found in peritoneal epithelia, tissue stromal cells, spleen, thymus, or blood-borne cells. Immunoblotting analysis showed that the MS2B6 epitope resides on polypeptides of 38, 44, and 60 kd. The cellular location of the MS2B6 antigen was studied with immunoperoxidase and immunofluorescent staining and immunoelectronmicroscopy of ovarian cancer ascites tumor cells. The results suggest that in ascites tumor cells the MS2B6 antigen is located in a layer of the peripheral cytoplasm beginning just below the cell membrane. MS2B6 may be useful as an imaging or therapeutic agent.

Adenocarcinoma↗