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Biomedical subjects

J S Chen

Publications and source records attributed to J S Chen.

At least 37 records · Page 2Linked to original sources

A method for in-vivo analysis for regional arterial wall material property alterations with atherosclerosis: preliminary results.

Atherosclerosis is a diffuse arterial disease developing over many years and resulting in a complicated three-dimensional arterial morphology. The arterial wall material properties have been demonstrated to show regional alterations with atheroma development and growth. We present a mechanical analysis of diseased arterial segments reconstructed from intravascular ultrasound images in order to quantitatively identify regional alterations in the elastic constants with atherosclerotic lesions. We employ a finite element and a displacement sensitivity analysis to divide the arterial segment into regions with different material properties and use an optimization algorithm to identify the elastic constants in these regions. The results with regional variations identified with this method correlated qualitatively with the extent and location of atherosclerotic lesions identified by visual inspection of the affected arteries. The optimized elastic modulus in regions affected by early atherosclerotic lesions ranged from 90.9 to 93.0 kPa where as the corresponding magnitudes in normal arterial segments ranged from 97.9 to 101.0 kPa. This method can be potentially employed to identify the extent and location of atherosclerotic lesions in a systematic analysis and may potentially be used for the early detection of lesion growth.

Animals↗

Gemcitabine and doxorubicin for the treatment of patients with advanced hepatocellular carcinoma: a phase I-II trial.

BACKGROUND: We determined the maximum tolerated dose (MTD) and then further evaluated the response rate and safety profile of gemcitabine (Gem) plus doxorubicin (Dox) in chemonaïve patients with advanced hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Dose escalation was tested over four dose levels in each 21-day cycle: level 1 (Gem 1000 mg/m(2) on days 1 and 8, Dox 30 mg/m(2) on day 1), level 2 (Gem/Dox 1250/30), level 3 (Gem/Dox 1250/45) and level 4 (Gem/Dox 1250/60). The MTD was further evaluated in phase II. RESULTS: Patients' characteristics were: 47 men, three women; median age 53 years (range 28-70); Zubrod performance status (PS) scores 0-1 (74%), PS 2 (26%); Okuda stage I (24%) and stage II (76%). Fifteen patients were enrolled in phase I: level 1 (n = 3), level 2 (n = 6), level 3 (n = 6), level 4 (n = 0). Level 2 was identified as the MTD. Dose-limiting toxicities included esophageal bleeding, grade 4 neutropenia and neutropenic fever. Of the 34 patients evaluable for response in phase II (of 35 total), there were four (11.8%) partial responses (95% CI, 0.8% to 22.8%) and six (17.6%) minor responses; nine (26.5%) had stable disease and 15 (44.1%) progressed. Sixteen per cent of patients had a decline of >or=50% in alpha-fetoprotein levels after treatment. Median survival and progression-free survival were 4.6 months (range 0.3-19.2) and 2.5 months (range 0.2-7.8), respectively, for 35 patients. Grade 3/4 hematological toxicities included anemia (45.7%), neutropenia (51.4%), thrombocytopenia (25.7%); febrile neutropenia (11.8%) and non-hematological toxicities were mild to moderate. CONCLUSIONS: Gemcitabine plus doxorubicin produces modest activity and moderate toxicity in this cohort of Chinese patients with advanced HCC.

Adult↗

Humoral response to p53 in human colorectal tumors: a prospective study of 1,209 patients.

p53 Antibodies (p53-Abs) have been detected in the serum of a proportion of colorectal cancer (CRC) patients. It is not yet known at which stage during colorectal tumor progression p53-Abs appear in the serum. The utility of these antibodies as markers for CRC prognosis remains to be clarified. Using a quantitative enzyme-linked immunosorbent assay, we analyzed serum samples from 998 CRC patients and from 211 patients with polyp. Levels of p53-Abs were defined as negative (<10 U/microL), low (10-76 U/microL) and high (>76 U/microL). Overall, 13.0% of CRC patients and less than 1% of polyp patients had increased serum p53-Ab levels. High p53-Ab levels were only seen in patients with invasive carcinomas. The parameters that were significantly and independently associated with a greater frequency of high p53-Ab levels were the left colon (odds ratio [OR] = 3.4; 95% CI = 1.1-10.5), the rectum (OR = 2.9; 95% CI, 1.0-8.8) and advanced lymph node metastasis (OR = 4.6; 95% CI, 2.2-9.6). In univariate analysis, patients with high p53-Ab levels had a shorter survival times than did those without (p = 0.007). However, the significant effect disappeared in a Cox regression model adjusting for sex, age, tumor location, carcinoembryonic antigen levels, gross findings, histologic grade, mucin production and TNM stage. Thus, autoantibodies against p53 occur with tumor progression in multistep colorectal carcinogenesis and increase with advanced node metastasis. Furthermore, the seemingly adverse effect of high p53-Ab levels on the survival of CRC patients may be explained by other prognostic factors.

Adult↗

Polarized absorption spectra of single-walled 4 A carbon nanotubes aligned in channels of an AlPO(4)-5 single crystal.

We report the polarized optical absorption spectra of single-walled 4 A carbon nanotubes arrayed in the channels of an AlPO (4)-5 single crystal. When the light electric field (E) is polarized parallel to the tube direction (c), the spectra display a sharp peak at 1.37 eV, with two broadbands at 2.1 and 3.1 eV. In the E perpendicular c configuration, the tube is nearly transparent in the measured energy region 0.5-4.1 eV. The optical dipole selection rules are discussed, and the absorption bands are assigned to the dipole transitions between the Van Hove singularities. The measured absorption spectra agreed well with the ab initio calculations of band structure based on the local density function approximation.

Journal Article↗

Identification of novel markers for monitoring minimal residual disease in acute lymphoblastic leukemia.

To identify new markers of minimal residual disease (MRD) in B-lineage acute lymphoblastic leukemia (ALL), gene expression of leukemic cells obtained from 4 patients with newly diagnosed ALL was compared with that of normal CD19(+)CD10(+) B-cell progenitors obtained from 2 healthy donors. By cDNA array analysis, 334 of 4132 genes studied were expressed 1.5- to 5.8-fold higher in leukemic cells relative to both normal samples; 238 of these genes were also overexpressed in the leukemic cell line RS4;11. Nine genes were selected among the 274 overexpressed in at least 2 leukemic samples, and expression of the encoded proteins was measured by flow cytometry. Two proteins (caldesmon and myeloid nuclear differentiation antigen) were only weakly expressed in leukemic cells despite strong hybridization signals in the array. By contrast, 7 proteins (CD58, creatine kinase B, ninjurin1, Ref1, calpastatin, HDJ-2, and annexin VI) were expressed in B-lineage ALL cells at higher levels than in normal CD19(+)CD10(+) B-cell progenitors (P <.05 in all comparisons). CD58 was chosen for further analysis because of its abundant and prevalent overexpression. An anti-CD58 antibody identified residual leukemic cells (0.01% to 1.13%; median, 0.03%) in 9 of 104 bone marrow samples from children with ALL in clinical remission. MRD estimates by CD58 staining correlated well with those of polymerase chain reaction amplification of immunoglobulin genes. These results indicate that studies of gene expression with cDNA arrays can aid the discovery of leukemia markers. (Blood. 2001;97:2115-2120)

Adolescent↗

Mechanism of colchicine-induced steroidogenesis in rat adrenocortical cells.

Conflicting data for the effects of colchicine on cholesterol transport and steroidogenesis raise the question of the role of microtubules in cholesterol transport from the lipid droplet to mitochondria in steroidogenic cells. In this study, using corticosterone radioimmunoassay and immunofluorescence microscopy, we re-evaluated the effects of colchicine on hormone production and morphological changes of lipid droplets' and studied the signaling pathway involved in colchicine-induced steroidogenesis. Colchicine stimulated steroid production in a dose- and time-dependent manner. The structural integrity of both the microtubules and the lipid droplet capsule was destroyed by colchicine treatment. Disruption of the lipid droplet capsule occurred later than microtubule depolymerization. After cessation of colchicine treatment and a 3 h recovery in fresh medium, capsular protein relocated to the droplet surface before the cytoplasmic microtubule network was re-established. beta-lumicolchicine, an inactive analogue of colchicine, disrupted the capsule and increased hormone production without affecting microtubular structure. Thus, microtubule depolymerization is not required for the increase in steroid production and capsular disruption. To explore the signaling pathway involved in colchicine-induced steroidogenesis, we measured intracellular cAMP levels. Unlike ACTH, colchicine did not increase cAMP levels, suggesting that the cAMP-PKA system is not involved. Colchicine and ACTH had additive effects on corticosterone production, whereas colchicine and PMA did not, implying that part of the PKC signaling mechanism may be involved in colchicine-induced steroidogenesis. Cycloheximide, a protein synthesis inhibitor, completely inhibited colchicine-induced steroidogenesis and capsular disruption. These results demonstrate that the steroid production and lipid droplet capsule detachment induced by colchicine are both protein neosynthesis-dependent and microtubule-independent.

Adrenal Cortex↗

The involvement of p38 MAPK in transforming growth factor beta1-induced apoptosis in murine hepatocytes.

We reported in this manuscript that TGF-beta1 induces apoptosis in AML12 murine hepatocytes, which is associated with the activation of p38 MAPK signaling pathway. SB202190, a specific inhibitor of p38 MAPK, strongly inhibited the TGF-beta1-induced apoptosis and PAI-1 promoter activity. Treatment of cells with TGF-beta1 activates p38. Furthermore, over-expression of dominant negative mutant p38 also reduced the TGF-beta1-induced apoptosis. The data indicate that the activation of p38 is involved in TGF-beta1-mediated gene expression and apoptosis.

Animals↗

Nitrogen-fixation genes and nitrogenase activity in Clostridium acetobutylicum and Clostridium beijerinckii.

Several solvent-producing clostridia, including Clostridium acetobutylicum and C. beijerinckii, were previously shown to be nitrogen-fixing organisms based on the incorporation of 15N2 into cellular material. The key nitrogen-fixation (nif) genes, including nifH, nifD, and nifK for nitrogenase component proteins as well as nifE, nifN, nifB and nifV for synthesis of the iron-molybdenum cofactor (FeMoco) of nitrogenase, have now been identified in C. acetobutylicum or C. beijerinckii or both. The organization of these genes is similar to the distinctive pattern that was first observed in Clostridium pasteurianum, with the nifN and nifB genes fused into the nifN-B gene and with the nifV gene split into the nifVomega and nifValpha genes. The corresponding nif genes of these three clostridial species are highly related to each other. However, in the two solvent-producing clostridia, the nifH and nifD genes are interspersed by two glnB-like genes, which are absent in the corresponding region in C. pasteurianum. However, the nifN-B and nifVomega genes of C. pasteurianum are interspersed by the putative modA and modB genes (for molybdate transport), which are absent in the corresponding region in C. acetobutylicum. C. acetobutylicum and C. beijerinckii grew well under nitrogen-fixing conditions, and the acetylene-reducing activity of nitrogenase was measured in the two species. Acetone, butanol, and isopropanol production occurred in nitrogen-fixing cultures, but the peak of nitrogen-fixing activity preceded the active solventogenic phase.

Acetylene↗

Endemicity and inter-city spread of Burkholderia cepacia genomovar III in cystic fibrosis.

OBJECTIVES: We sought to determine whether the same Burkholderia cepacia complex strain has persisted as the dominant clonal lineage among patients in a large cystic fibrosis (CF) treatment center during the past 2 decades. STUDY DESIGN: The inter-city spread of B cepacia through transfer of a colonized patient and the impact of infection control measures in containing inter-patient transmission were investigated. We analyzed all available B cepacia complex isolates recovered from 1981 to 1987 and from 1996 to 2000 at one large CF treatment center (Center A) and from 1997 to 2000 at another center (Center B). Incidence of B cepacia complex infection and infection control measures in both centers were assessed. RESULTS: Seventeen (81%) of 21 Center A patients from whom B cepacia complex bacteria were recovered between 1981 and 1987 and 40 (97%) of 41 patients culture-positive between 1996 and 2000 were infected with the same genomovar III strain. Transfer of a colonized patient from Center A to Center B was associated with an increase in B cepacia complex infection in Center B, all of which was with the Center A dominant strain. This strain, designated PHDC, lacks both B cepacia epidemic strain and cblA markers. CONCLUSIONS: B cepacia complex strains may remain endemic in CF treatment centers for many years. Responsible bacterial and host factors and optimal infection control measures to prevent inter-patient spread remain to be identified.

Bacterial Typing Techniques↗

Bradykinin induces protein kinase C-dependent activation of phospholipase D in A-431 cells.

The protein kinase C involvement in bradykinin (BK)-induced phospholipase D (PLD) activation in A-431 cells was examined. Treatment of cells with BK induced the rapid activation of intracellular PLD activity. The PLD activation induced by BK was blocked by pretreatment of A-431 cells with staurosporine, or by prolonged treatment with phorbol-12-myristate-13-acetate (PMA). PKC inhibitors Ro-31-8220 and bisindolylmaleimide I, showed the same inhibitory effects on the BK-stimulated increase of PLD activity, indicating a role of PKC in this activation process. Similar results were observed in PMA-induced PLD activation. In contrast, PKC down-regulation or PKC inhibitors had no obvious effect on the PLD activation stimulated by epidermal growth factor (EGF). Furthermore, rottlerin and Go 6976, the PKC inhibitors specific for PKC-delta, -alpha and -betaI, respectively, markedly inhibited the PLD activity stimulated by BK. These results indicated that PKC, at least PKC-delta and Ca2+-dependent PKC-alpha or -betaI, plays an important role in BK-induced but not EGF-induced PLD activation in A-431 cells.

Acetophenones↗

Severe reversible bone marrow suppression induced by Selaginella doederleinii.

CASE REPORT: We report a 52-year-old female patient with cholangiocarcinoma who developed severe bone marrow suppression after taking Selaginella doederleinii as an alternative anticancer treatment. She developed severe pancytopenia with initial presentations of skin ecchymosis, itching, and gum bleeding 2 weeks after taking Selaginella doederleinii daily. Bone marrow smear and biopsy showed severe hypocellularity with no malignant cell infiltration. Approximately 1 week after stopping Selaginella doederleinii, her hemogram returned to previous levels. Selaginella doederleinii, a popular anticancer herb, may contain an as yet unidentified substance that contributes to reversible bone marrow suppression.

Antineoplastic Agents, Phytogenic↗

Weekly high-dose 5-fluorouracil (5-FU), leucovorin (LV) and bimonthly cisplatin in patients with advanced gastric cancer.

BACKGROUND: A phase II clinical trial was performed to evaluate the activity and toxicity of bimonthly cisplatin and weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin in patients with advanced gastric cancer. PATIENTS AND METHODS: From September 1997 to March 1998, 23 chemo-naive patients of advanced gastric cancer were enrolled in this study. The regimen consisted of weekly 24-h infusion of 5-FU (2,600 mg/m2) and LV 150 mg and bimonthly cisplatin (25-50 mg/m2) bolus for 12 weeks followed by a 2-week break. RESULTS: There were 10 male and 13 female patients with a median age of 52 years. A total of 428 chemotherapy treatments were given with a mean of 11. Seventeen patients were evaluable for response. There were 41% (7/17) partial response, 18% (3/17) stable disease and 41% (7/17) progressive disease. The grade III or IV toxicity included anorexia 35% (8/23), fatigue 26% (6/23), vomiting 17% (4/23) and mucositis 9% (2/23). One patient developed perforated duodenal stump after chemotherapy. One patient died of hyperammonemia-related coma. The median times to disease progression and overall survival were 3.5 and 7 months, respectively. CONCLUSIONS: This regimen showed modest activity against gastric cancer. However, there was no survival advantage and there was greater toxicity than with weekly high-dose 5-FU-LV alone.

Adult↗

Risk factors for surgical site infection after elective resection of the colon and rectum: a single-center prospective study of 2,809 consecutive patients.

OBJECTIVE: To identify the risk factors for surgical site infection (SSI) in patients undergoing elective resection of the colon and rectum. SUMMARY BACKGROUND DATA: SSI causes a substantial number of deaths and complications. Determining risk factors for SSI may provide information on reducing complications and improving outcome. METHODS: The authors performed a prospective study of 2,809 consecutive patients undergoing elective colorectal resection via laparotomy between February 1995 and December 1998 at a single institution. The outcome of interest was SSI, which was classified as being incisional or organ/space with or without clinical leakage. A likelihood ratio forward regression model was used to assess the independent association of variables with SSIs. RESULTS: The overall SSI, incisional SSI, and organ/space SSI with and without clinical anastomotic leakage rates were 4.7%, 3%, 2%, and 0.8%, respectively. Risk factors for overall SSI were American Society of Anesthesiology (ASA) score 2 or 3 (odd ratio [OR] = 1.7), male gender (OR = 1.5), surgeons (OR = 1.3-3.3), types of operation (OR = 0.3-2.1), creation of ostomy (OR = 2.1), contaminated wound (OR = 2.9), use of drainage (OR = 1.6), and intra- or postoperative blood transfusion (1-3 units, OR = 5.3; >/=4 units, OR = 6.2). However, SSIs at specific sites differed from each other with respect to the risk factors. Among a variety of risk factors, only blood transfusion was consistently associated with a risk of SSI at any specific site. CONCLUSIONS: In addition to ASA score and surgical wound class, blood transfusion, creation of ostomy, types of operation, use of drainage, sex, and surgeons were important in predicting SSIs after elective colorectal resection.

Adolescent↗

Intra-arterial plus i.v. chemotherapy for advanced bulky squamous cell carcinoma of the buccal mucosa.

From July 1994 to December 1996, 41 patients with previously untreated, advanced bulky squamous cell carcinoma arising from the buccal mucosa (BSCC) were enrolled. All patients were males with a median age of 47 years (range 29-72). The tumor extent was stage III/IV: three of 38, T4: 85%, N2-3: 20%. Patients were initially scheduled to receive intra-arterial (i.a.) chemotherapy, followed by i.v. chemotherapy and regional therapy. The i.a. chemotherapy catheter was properly placed by external carotid artery angiography via the femoral artery. The i.a. chemotherapy consisted of cisplatin (P) 100 mg/m(2) day 1 plus 5-fluorouracil (F) 1000 mg/m(2) day 1-4, and the i.v. chemotherapy consisted of PF (10 patients) or PF plus methotrexate 200 mg/m(2) day 15 and 22 (31 patients). All chemotherapy regimens were administered at 4-week intervals. The response rate of i.a. plus i.v. chemotherapy for the primary site was 85% (35 of 41) with 29% complete remission (CR) (12 of 41). The response and CR rates of neck nodes were 82% (14 of 17) and 41% (seven of 17), respectively. The combined overall response rate was 80% (33 of 41) with a 29% CR (12 of 41). Major toxicity from i.a. chemotherapy of WHO grade > or = 3 included: mucositis of infusion area (76%), hemialopecia (56%) and leukopenia (5%). Three neurologic complications of i.a. chemotherapy including one hemiparesis occurred. The median follow-up time was 47 months (range 36-66 months), and the overall survival and disease-free survival were both 34% (14 of 41). Four patients were cured with chemotherapy alone and eight patients (19.5%) were cured without surgical intervention. Using i.a. chemotherapy as a cytoreductive therapy followed by subsequent i.v. chemotherapy produces a high response rate and an encouraging degree of complete response rate in advanced bulky BSCC. However, toxicity management and catheter placement will need to be improved in order to better define the role of this therapy in advanced BSCC.

Adult↗

Mitomycin C with weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin in patients with biliary tract and periampullar carcinomas.

We have reported a 33% partial response rate with acceptable toxicity using weekly 24-h infusion of high-dose 5-fluorouracil (5-FU) and leucovorin (LV) in patients with far advanced biliary tract cancers (BTC). In this study, we added mitomycin (MMC) to 5-FU and LV in an attempt to improve the response rate and survival. From July 1997 to September 1999, 25 chemotherapy-naive patients with pathology-proven far advanced BTC and periampullar cancers were enrolled. The regimen consisted of MMC 10 mg/m(2) every 8 weeks combined with 5-FU 2600 mg/m(2) and LV 150 mg at a schedule of 24-h infusion weekly for 6 weeks followed by a 2 week break. There were 10 males and 15 females with a median age of 57 years (range 40-76). The sites of primary tumor were 15 intrahepatic cholangiocarcinomas (CC), one perihilar CCs, three distal BTC, three gallbladder cancers (GB) and three periampullar cancers. A total of 148 sessions of chemotherapy were given with a mean of 8 (range 2-18). Nineteen patients were evaluable for response. The response rate was: 26% (five of 19) partial response, 42% (eight of 19) stable disease and 32% (six of 19) progressive disease. All of the patients were evaluable for toxicity. Toxicities more than grade III-IV were thrombocytopenia 16% (four of 25), leukopenia 12% (three of 25) and vomiting 4% (one of 25). There were four treatment-related deaths. The median time to disease progression was 3 months. The median survival was 6 months. A combination of MMC with weekly high-dose 5-FU and LV in patients with BTC did not improve the response rate, but produced more toxicity than weekly high-dose 5-FU and LV alone.

Adenocarcinoma↗

A comparison of scar revision with the free electron and carbon dioxide resurfacing lasers.

Laser scar revision was studied to measure the effects of targeting extracellular matrix protein versus tissue water on scar revision. We compared the free electron laser used at 7.7 microm (the amide III protein absorption band) to the carbon dioxide (CO2) laser and dermabrasion.Nude mice (n = 40) that had rejected skin grafts on their dorsal surface and developed mature scars were used as a model for scar revision. One-half of each scar was revised with either the free electron laser at 7.7 microm (32 to 38 mJ, nonoverlapping pulses delivered with a computerized adjustable pattern generator at 30 Hz, and two to three passes), a 100-microsec CO2 resurfacing laser (500 mJ, 5.0 Hz, and two to five passes), or dermabrasion. The untreated portion of each scar served as an internal control. Evaluation was by measurement of the clinical size of the scar using photography with quantitative computer image analysis to compare the data and histology to evaluate the quality and depth of the scars. The free electron laser at 7.7 microm was significantly better than the CO2 laser and dermabrasion for scar size reduction (p < 0.046 and p < 0.018). The CO2 laser and a highly skilled dermabrader were not statistically significantly different (p < 0.44). The result seen with less skilled dermabraders was significantly worse than all other methods (p < 0.009). The free electron laser at 7.7 microm, which is preferentially absorbed by the proteins of the extracellular matrix, provided better scar reduction than the CO2 resurfacing laser and dermabrasion. Dermabrasion by a skilled operator resulted in improvement similar to the results obtained with the CO2 resurfacing laser, but less skilled operators had significantly poorer results.

Animals↗

Inhibition of inducible nitric oxide synthase (iNOS) prevents lung neutrophil deposition and damage in burned rats.

This study was designed to investigate the role of NO and effect of iNOS inhibitor on the lung neutrophil deposition and damage after burn. In Experiment 1, specific pathogen-free (SPF) Sprague-Dawley rats underwent 35% total body surface area (TBSA) burn. On the 4th, 8th, 16th, and 24th h after burn, blood was collected for peroxynitrite-mediated dihydrorhodamine 123 (DHR 123) oxidation assay, and lung tissues were harvested for myeloperoxidase (MPO) test and histologic study. Pulmonary microvascular dysfunction was quantitated by measuring the extravasation of Evans blue dye (EBD). In Experiment 2, S-methylisothiourea (SMT) was given (7.5 mg/kg, intraperitoneal immediately post-burn) to suppress iNOS activity. On the 8th h after burn, the effect of SMT on blood DHR 123 oxidation, lung MPO, lung damage, and lung iNOS expression were evaluated. Lung MPO activity increased up to a maximum of 2-fold 8 h after burn. Blood DHR 123 oxidation increased up to a maximum of 2-fold 8 h after burn. Lung permeability increased up to a maximum of 2.5-fold 4 h after burn. SMT significantly decreased lung MPO activity, blood DHR 123 oxidation, and lung permeability by 31%, 41%, and 54%, respectively. SMT markedly decreased the thermal injury-induced perivascular and interstitial inflammatory cell infiltration and iNOS staining in bronchiolar epithelium, endothelial cells, and perivascular and interstitial inflammatory cells. In conclusion, thermal injury induces blood DHR 123 oxidation, lung neutrophil deposition, lung iNOS expression, and lung damage. Peroxynitrite might play an important role in thermal injury-induced lung neutrophil deposition and damage. Specific inhibition of lung iNOS expression and blood DHR 123 oxidation with SMT on thermal injury not only attenuated the lung neutrophil deposition, but also reduced lung damage.

Animals↗

Possible origin of extrachromosomal DNA from human lymphocytes following in vitro treatment by phytohemagglutinin.

Lymphocytes respond to chemical or pathological challenges by synthesizing episomes or extrachromosomal DNA (eDNA). Phytohemagglutinin (PHA) is a mitogen for T lymphocytes and can stimulate the increased production of episomes as well as the release of eDNA, interleukin-2, and other factors. However, the origin of this eDNA is largely unknown. To confirm the observation on the localization of an antibody directed against a 23-kb segment of bull acrosomal DNA in cultured human lymphocytes, we performed analyses by fluorescence in situ hybridization (FISH) using the same DNA as a molecular probe.

Cells, Cultured↗