[Analysis of the feasibility and prognostic value of circulating tumor DNA monitoring in detecting gene mutations in patients with diffuse large B-cell lymphoma receiving chimeric antigen receptor T-cell therapy].

Objective: To explore the prognostic value of circulating tumor DNA (ctDNA) testing in patients with refractory/relapsed diffuse large B-cell lymphoma (R/R DLBCL) undergoing chimeric antigen receptor T-cell (CAR-T) therapy, and to guide the prevention and subsequent treatment of CAR-T-cell therapy failure. Methods: In this study, 48 patients with R/R DLBCL who received CAR-T-cell therapy at the First Affiliated Hospital of Zhejiang University School of Medicine between December 2017 and March 2022 were included. Furthermore, ctDNA testing of 187 lymphoma-related gene sets was performed on peripheral blood samples obtained before treatment. The patients were divided into complete remission and noncomplete remission groups. The chi-square test and t-test were used to compare group differences, and the Log-rank test was used to compare the differences in survival. Results: Among the patients who did not achieve complete remission after CAR-T-cell therapy for R/R DLBCL, the top ten genes with the highest mutation frequencies were TP53 (41%), TTN (36%), BCR (27%), KMT2D (27%), IGLL5 (23%), KMT2C (23%), MYD88 (23%), BTG2 (18%), MUC16 (18%), and SGK1 (18%). Kaplan-Meier survival analysis revealed that patients with ctDNA mutation genes >10 had poorer overall survival (OS) rate (1-year OS rate: 0 vs 73.8%, P<0.001) and progression-free survival (PFS) rate (1-year PFS rate: 0 vs 51.8%, P=0.011) compared with patients with ctDNA mutation genes ≤10. Moreover, patients with MUC16 mutation positivity before treatment had better OS (2-year OS rate: 56.8% vs 26.7%, P=0.046), whereas patients with BTG2 mutation positivity had poorer OS (1-year OS rate: 0 vs 72.5%, P=0.005) . Conclusion: ctDNA detection can serve as a tool for evaluating the efficacy of CAR-T-cell therapy in patients with R/R DLBCL. The pretreatment gene mutation burden, mutations in MUC16 and BTG2 have potential prognostic value.

The relationship between famine exposure in early life and left atrial enlargement in adulthood.

BACKGROUND: Increased left atrium diameter (LAD) is associated with an elevated risk of cardiovascular diseases. The relationship between nutrition status and left atrial enlargement (LAE) is still unclear. The present study aimed to investigate the association of famine exposure in early life with LAE in adulthood. METHODS: Participants were divided into non-exposed, fetal, early, middle and late childhood exposed groups according to birth data. LAE was defined when LAD was ≥3.9 cm in women and ≥4.1 cm in men, or ≥2.3 cm m-2 by a sex-independent cut-off normalised for body surface area. Multivariate logistic regression was performed to calculate the odds ratio (OR) and confidence interval (CI) between famine exposure and LAE. RESULTS: In total, 2522 [905 male, mean (SD) age 59.1 (3.65) years] subjects were enrolled, including 392 (15.5%) LAE subjects. The prevalence of LAE in non-exposed, fetal, early, middle and late childhood exposed groups was 55 (10.8%), 38 (11.2%), 88 (18.1%), 102 (16.7%) and 109 (19.0%), respectively. Compared to the non-exposed group, the ORs for LAE were in fetal (OR = 0.956, 95% CI = 0.605-1.500, P = 0.847), late (OR = 1.748, 95% CI = 1.208-2.555, P = 0.003), middle (OR = 1.647, 95% CI = 1.140-2.403, P = 0.008) and early (OR = 1.630, 95% CI = 1.116-2.399, P = 0.012) childhood exposed groups after adjusting potential cofounders. When stratified by gender, smoking, body mass index, hypertension and diabetes, we found that the effect of famine exposure on LAE was only modified by diabetes (Pinteraction  = 0.007). CONCLUSIONS: Famine exposure during childhood stage might increase the risk of LAE in adults, and this effect interacts with diabetes.

The Relationship between Telomere Length and Cancer Mortality: Data from the 1999-2002 National Healthy and Nutrition Examination Survey (NHANES).

OBJECTIVES: The association between telomeres length (TL) and cancer mortality is uncertain. We tested the hypotheses that long TL are associated with reduced cancer mortality. DESIGN: Prospective cohort study. SETTING: the National Health and Nutrition Survey (NHANES, 1999-2002). PARTICIPANTS: The analytic sample included adults (n = 7183) who had TL measurements. MEASUREMENTS: DNA was obtained via blood samples. Telomere length was assessed using the quantitative polymerase chain reaction method. RESULTS: During follow-up (0.08-12.7 person-years, median = 9.5 years), we observed 195 participants had cancer as causes of death. TL was negatively corelated with age, body mass index (BMI), systolic blood pressure (SBP), C-reactive protein (CRP), race, diabetes, hypertension, cardiovascular diseases (CVD) and cancer mortality, conversely, positively corelated with alcohol use, but not related to diastolic blood pressure (DBP) and smoking. Kaplan-Meier analysis revealed that TL was significantly associated with cancer mortality (log-rank, P <0.001). CONCLUSIONS: Our study expands upon previous evidence of a relationship between TL and cancer mortality. TL may be a useful tool for evaluating risk of cancer mortality in American adults.

[Expression of GTF2IP23 in breast cancer and it mediated regulation of GTF2I].

Objective: To investigate the expression level of antisense transcript of pseudogene, general transcription factor Ⅱi psedugen23 (GTF2IP23), in breast cancer and its effect on the host gene general transcription factor Ⅱi (GTF2I). Methods: The expressions of GTF2IP23 and GTF2I were detected in 40 cases of invasive breast cancer tumors and their counterparts by using quantitative real-time polymerase chain reaction (qRT-PCR). The effects of GTF2IP23 on the expression of GTF2I gene and cell proliferation and migration were analyzed by overexpression of GTF2IP23 in breast cancer cells. Results: The expression of GTF2IP23 mRNA in breast cancer tissues was significantly higher than that in adjacent tissues (P<0.001), while the expression of GTF2I mRNA was significantly lower than that in adjacent tissues (P=0.007). The expression of GTF2IP23 was negatively correlated with GTF2I (r=-0.335, P=0.025). The expression of GTF2IP23 in breast cancer cells was significantly higher than in normal breast cells (P<0.01), while GTF2I expression in breast cancer cells was significantly lower than that in normal breast cells (P<0.01). Overexpression of GTF2IP23 in ZR-75-30 cells significantly reduced the expression of GTF2I (P=0.034) and enhanced cell proliferation (P=0.017) and migration (P=0.026) capacity. Conclusions: GTF2IP23 is distinctly upregulated in breast cancer, it inhibits the expression of real gene GTF2I and promotes the proliferation of breast cancer cells.

Association between interleukin-17 gene polymorphisms and the risk of laryngeal cancer in a Chinese population.

IL-17 is associated with the occurrence and development of laryngeal cancer. However, no study has reported the association between IL-17 polymorphisms and laryngeal cancer susceptibility. Therefore, we analyzed the association of three polymorphism loci (rs2275913, 197 G/A; rs3748067, 383 A/G; and rs763780, 7488 T/C) of IL-17A and IL-17F with laryngeal cancer in the Chinese population. A case-control study was performed with 325 patients and 325 controls. Polymorphisms were detected by polymerase chain reaction and sequencing methods. SPSS17.0 software was used for statistical analysis. Allele and genotype frequencies of IL-17A rs2275913 were significantly different between patients and controls (P < 0.05). Frequencies of rs2275913 (197 G/A) AA and GA+AA genotypes compared to the GG genotype were significantly higher in patients than in controls, indicating the association of these genes with laryngeal cancer susceptibility; adjusted OR values were 2.54 (1.50-4.23) and 1.62 (1.19-2.17), respectively. Furthermore, individuals with the GA+AA genotype, compared to the GG genotype, aged ≤60 years, with smoking and alcohol consumption habits, and without a family history of cancer showed a higher cancer risk (OR = 2.74, 95%CI = 1.41-5.23; OR = 2.11, 95%CI = 1.21-3.55; OR = 1.91, 95%CI = 1.02-3.70; OR = 1.99, 95%CI = 1.08-3.39, respectively). In conclusion, the rs2275913 IL-17A (197 G/A) is associated with the incidence and development of laryngeal cancer in the Chinese population, and the AA and GA+AA genotypes harbor a high laryngeal cancer risk.

Anti-tumor role of Bacillus subtilis fmbJ-derived fengycin on human colon cancer HT29 cell line.

To explore the potential clinical anti-tumor roles of Bacillus subtilis fmbJ-derived fengycin on cell growth and apoptosis in colon cancer HT29 cell line.Fengycin was extracted from Bacillus subtilis fmbJ and detected using HPLC. The effects of different concentration of fengycin on colon cell HT29 cell activity at different time points were analyzed using MTT assay. ROS level in colon HT29 cells affected by fengycin was detected using DCFH-DA method, followed by measuring the effects of fengycin on HT29 cell apoptosis and cell cycle by flow cytometry. The effects of fengycin on Bax/Bcl-2, CDK4/cyclin D1, Caspase-6 and Caspase-3 expressions in HT29 cells were analyzed using western blot. Also, mRNA levels of Bax/Bcl-2 and CDK4/cyclin D1 in HT29 cells affected by fengycin were analyzed using qRT-PCR.Compared with controlss, 20 µg/mL of fengycin performed an inhibit role on HT29 cell growth of at 3 day (P<0.05), and high dose of fengycin showed more excellent effect on inhibiting HT29 cell growth with time increasing. Besides, fengycin could induce HT29 cell apoptosis and affect the cell cycle arrest at G1. ROS level in HT29 cells treated by fengycin was significantly increased compared with that in control group (P<0.05). Western blot analysis showed that after being treated with fengycin, Bax, Caspase-3, and Caspase-6 expressions were increased, however, Bcl-2, and CDK4/cyclin D1 expressions were decreased (P<0.05).Our study suggested that fengycin may play certain inhibit roles in the development and progression of colon cancer through involving in the cell apoptosis and cell cycle processes by targeting the Bax/Bcl-2 pathway.

Lack of association between the cyclooxygenase 2 -765G>C polymorphism and prostate cancer risk: a meta-analysis.

The aim of this study was to investigate the association between the cyclooxygenase 2 (COX2) -765G>C (rs20417) polymorphism and prostate cancer (PC) risk using meta-analysis. A systematic literature search was performed using the PubMed, Embase, Cochrane Library, and Google Scholar databases by using the terms "cyclooxygenase-2/COX-2/PTGs2", "polymorphism" or "variation", and "prostate" and "cancer" or "carcinoma" to identify relevant articles up to June 14, 2014. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were assessed for PC risk associated with COX2 -765G>C polymorphism using fixed- and random-effect models. We identified a total of nine publications, including 5952 cases and 5078 controls, to investigate the effect of COX2 -765G>C on PC risk, and found no significant association in any genetic model tested (CC vs GG: OR = 0.993, 95%CI = 0.923-1.068; GC+CC vs GG: OR = 1.041, 95%CI = 0.931-1.103; CC vs GC+GG: OR = 0.858, 95%CI = 0.689-1.067; CC vs GG: OR = 0.871, 95%CI = 0.689-1.086; GC vs GG: OR = 1.032, 95%CI = 0.945-1.127). Power analysis and tests for publication bias ensured the reliability of our results. This meta-analysis suggested that the functional COX2 -765G>C polymorphism, located in the COX2 gene promoter, is unlikely to be associated with PC risk. However, additional larger, well-designed studies are still required to reach a conclusive result on this issue.

Inducible nitric oxide inhibitor enhances the anti-tumor effect of cisplatin on CNE-2 cells by inducing cell apoptosis.

OBJECTIVE: Inducible nitric oxide (NO) synthase (iNOS) inhibitor S-methylisothiourea (SMT) has been reported to have anti-tumor effects on several types of cancers.  We aimed to investigate whether SMT can inhibit nasopharyngeal carcinoma cells CNE-2 proliferation through raise chemotherapy effect of diaminodichloroplatinum (DDP). MATERIALS AND METHODS: CNE-2 cells were treated with SMT, DDP and both of them respectively. MTT and colony-forming assay was performed to detect the proliferation effect of the treatment. Hoechst 33258 staining and apoptosis analysis were performed to investigate the apoptosis effect of chemotherapy. Additionally, the NO level was detected to estimate the activity of iNOS. RESULTS: CNE-2 cells expressed high level of iNOS. SMT can inhibit CNE-2 cells growth in a dose-dependent manner and have the effect on reducing dosage of DDP as well as enhancing the anti-tumor efficacy by promote cell apoptosis. CONCLUSIONS: Our findings suggested that SMT play a synergism role in the inhibition process of DDP on nasopharyngeal carcinoma, and SMT could be a promising therapeutic factor for cancer prevention.

Abnormal regulation for progesterone production in placenta with prenatal cocaine exposure in rats.

Cocaine abuse in pregnant women is currently a significant public hygiene problem and is tightly associated with elevated risk for preterm delivery. Placental steroidogenesis especially progesterone production was essential for success and maintenance of pregnancy in humans and rodents. In the present study, we determined the impact of prenatal cocaine exposure on pathways of placental progesterone synthesis in rats. Pregnant rats were treated cocaine twice daily (15 mg/kg/day) during the third trimester, and the maternal and fetal plasma progesterone and pregnenolone concentrations were detected. We also examined both the protein and mRNA expression of some key enzymes and regulators for progesterone production in placenta. Results showed that, after maternal cocaine use during pregnancy, progesterone and pregnenolone concentrations in both maternal and fetal rats were significantly decreased. Although prenatal cocaine exposure had no effects on placental 3ß-hydroxysteroid dehydrogenase type 1 (3ßHSD1) expression, protein and mRNA expression of the cholesterol side-chain cleavage enzyme (P450scc/CYP11a) in placenta was significantly inhibited. Moreover, protein and mRNA expressions of MLN64 that regulating cholesterol transport and activating protein 2γ (AP2γ/Tfap2c) that controlling P450scc/CYP11a gene expression in placenta were both decreased following maternal cocaine use in pregnancy. Collectively, this study suggested that prenatal cocaine exposure could insult the placental progesterone production in rats possibly associated with the high risk for preterm delivery.

Sequences flanking hypersensitive sites of the beta-globin locus control region are required for synergistic enhancement.

The major distal regulatory sequence for the beta-globin gene locus, the locus control region (LCR), is composed of multiple hypersensitive sites (HSs). Different models for LCR function postulate that the HSs act either independently or synergistically. To test these possibilities, we have constructed a series of expression cassettes in which the gene encoding the enhanced green fluorescent protein (EGFP) is under the control of DNA fragments containing single and multiple HSs of the LCR. LCR DNA fragments containing only the minimal region needed for position-independent expression (HS cores) or containing cores plus flanking sequences (HS units) were compared to ascertain whether conserved sequences between the HS cores contributed to enhancement. Expression of these constructs was measured after targeted integration into three defined loci in murine erythroleukemia cells using recombinase-mediated cassette exchange. At all three marked loci, synergistic enhancement of expression was observed in cassettes containing a combination of HS2, HS3, and HS4 units. In contrast, HS2, HS3, and HS4 cores (without flanking sequences) give an activity equivalent to the sum of the activities of the individual HS cores. These data suggest a model in which an HS core plus flanking regions, bound by specific proteins, forms a structure needed for interaction with other HS units to confer strong enhancement by the LCR. The three targeted integration sites differ substantially in their permissivity for expression, but even the largest LCR construct tested could not overcome these position effects to confer equal expression at all three sites.

Position effects are influenced by the orientation of a transgene with respect to flanking chromatin.

We have inserted two expression cassettes at tagged reference chromosomal sites by using recombinase-mediated cassette exchange in mammalian cells. The three sites of integration displayed either stable or silencing position effects that were dominant over the different enhancers present in the cassettes. These position effects were strongly dependent on the orientation of the construct within the locus, with one orientation being permissive for expression and the other being nonpermissive. Orientation-specific silencing, which was observed at two of the three site tested, was associated with hypermethylation but not with changes in chromatin structure, as judged by DNase I hypersensitivity assays. Using CRE recombinase, we were able to switch in vivo the orientation of the transgenes from the permissive to the nonpermissive orientation and vice versa. Switching from the permissive to the nonpermissive orientation led to silencing, but switching from the nonpermissive to the permissive orientation did not lead to reactivation of the transgene. Instead, transgene expression occurred dynamically by transcriptional oscillations, with 10 to 20% of the cells expressing at any given time. This result suggested that the cassette had been imprinted (epigenetically tagged) while it was in the nonpermissive orientation. Methylation analysis revealed that the methylation state of the inverted cassettes resembled that of silenced cassettes except that the enhancer had selectively lost some of its methylation. Sorting of the expressing and nonexpressing cell populations provided evidence that the transcriptional oscillations of the epigenetically tagged cassette are associated with changes in the methylation status of regulatory elements in the transgene. This suggests that transgene methylation is more dynamic than was previously assumed.

Myocardial extracellular matrix remodeling in transgenic mice overexpressing tumor necrosis factor alpha can be modulated by anti-tumor necrosis factor alpha therapy.

Myocardial fibrosis caused by maladaptive extracellular matrix (ECM) remodeling is implicated in the dysfunction of the failing heart. Matrix metalloproteinases (MMPs) regulate ECM remodeling, and are regulated by cytokines. Transgenic mice with cardiac-specific overexpression of tumor necrosis factor alpha (TNF-alpha) (TNF1.6) develop heart failure. We hypothesized that modulation of TNF-alpha and/or MMP activity might alter the myocardial ECM remodeling process and the development of heart failure. To test this hypothesis, we took advantage of the TNF1.6 mice and studied soluble and total collagens and collagen type profiling by using hydroxyproline quantification, Sircol collagen assay, Northern blot analysis, and immunohistochemistry and studied myocardial function by using echocardiography. Progressive ventricular hypertrophy and dilation in the TNF1.6 mice were accompanied by a significant increase in MMP-2 and MMP-9 activity, an increase in collagen synthesis, deposition, and denaturation, and a decrease in undenatured collagens. In young TNF1.6 mice, these changes in the ECM were associated with marked diastolic dysfunction as demonstrated by significantly reduced transmitral Doppler echocardiographic E/A wave ratio. Anti-TNF-alpha treatment with adenoviral vector expressing soluble TNF-alpha receptor type I attenuated both MMP-2 and MMP-9 activity, prevented further collagen synthesis, deposition and denaturation, and preserved myocardial diastolic function in young, but not old, TNF1.6 mice. The results suggest a critical role of TNF-alpha and MMPs in myocardial matrix remodeling and functional regulation and support the hypothesis that both TNF-alpha and MMPs may serve as potential therapeutic targets in the treatment of heart failure.

Site-specific chromosomal integration in mammalian cells: highly efficient CRE recombinase-mediated cassette exchange.

Expression of experimental constructs in mammalian cells or transgenic animals is difficult to control because it is markedly influenced by position effects. This has limited both the analysis of cis -DNA regulatory elements for transcription and replication, and the physiological analysis of proteins expressed from transgenes. We report here two new methods based on the concept of recombinase-mediated cassette exchange (RMCE) to perform site-specific chromosomal integration. The first method permits the exchange of a negative selectable marker pre-localized on the chromosome with a transgene via a CRE-mediated double recombination between inverted Lox sites. Integration efficiency is close to 100 % of negatively selected mouse erythroleukemia cells and ranges from 10 to 50 % in embryonic stem cells. The second method allows RMCE with no selection at all except for cells that have taken up plasmid transiently. While less efficient, this technique permits novel experimental approaches. We find that integration of a transgene at a given genomic site leads to reproducible expression. RMCE should be useful to develop artificial genetic loci that impart specific and reproducible regulation of transgenes in higher eukaryotes. This should facilitate the analysis of cis -regulatory DNA elements governing expression and position effects, improve our control over the physiological effects of transgenes, and accelerate the development of animal models for complex human diseases.

Enhancer-dependent transcriptional oscillations in mouse erythroleukemia cells.

By using recombinase-mediated cassette exchange, a method that allows integration of single copies of different constructs at the same predetermined chromosomal location, several expression cassettes have been integrated at a randomly chosen locus in the genome of mouse erythroleukemia cells. The cassettes studied contain the human beta-globin promoter fused to lacZ coding sequences either alone or linked to DNase I-hypersensitive site HS2, HS3, or HS234 (a large locus control region fragment containing HS2, HS3, and HS4) of the human beta-globin locus control region. Analysis of expression of these cassettes revealed mosaic expression patterns reminiscent of, but clearly different from, position effect variegation. Further investigations demonstrated that these mosaic expression patterns are caused by dynamic activation and inactivation of the transcription unit, resulting in oscillations of expression. These oscillations occur once in every few cell cycles at a rate specific for the enhancer present at the locus. DNase I sensitivity studies revealed that the chromatin is accessible and that DNase-hypersensitive sites were present whether or not the transcription unit is active, suggesting that the oscillations occur between transcriptionally competent and transcriptionally active chromatin conformations, rather than between open and closed chromatin conformations. Treatment of oscillating cells with trichostatin A eliminates the oscillations only after the cells have passed through late G1 or early S, suggesting that these oscillations might be caused by changes in histone acetylation patterns.

[Microwave technique in hepatic surgery: report of 70 cases].

70 hepatic resections were performed using 2450 MHz microwave scalpel. Primary diseased included hepatocellular carcinoma (46 cases), hemangioma (18), hepatobiliary tract stone (2), biliary cystadenoma (1), inflammatory pseudotumor of the live (1), metastatic liver cancer (2). Hemostasis was excellent despite liver cirrhosis in all cases. The average amount of blood loss and blood transfusion was 249 ml and 294 ml respectively. Blood transfusion was not necessary in 30 patients. All cases were free from postoperative bleeding from the liver stump and abdominal infection. No complications attributable to microwave coagulation were noted. We conclude that this new operative technique can be used safely and easily in the field of hepatic surgery.

Effect of heme binding on the structure and stability of Escherichia coli apocytochrome b562.

The structure and stability of apocytochrome b562 were explored using absorption and circular dichroism spectroscopic methods. The polypeptide chain retains a well-defined structure when the prosthetic heme group is removed from cytochrome b562. Circular dichroism measurements estimate 60% helicity for apocytochrome b562, compared with 80% helicity found in holocytochrome b562. At low pH, apocytochrome b562 displays a midpoint pH of 2.9, while ferricytochrome b562 displays a midpoint pH of 2.3. The unfolding of the apoprotein by urea and heat can be well approximated by the two-state transition model. The stability of apocytochrome b562 is significantly reduced from that of the holoprotein. The free energy of stabilization (delta G degrees) and the midpoint transition temperature (Tm) for apocytochrome b562 are found to be 3.2 +/- 0.5 kcal/mol and 52.3 +/- 0.9 degrees C, respectively, compared with 6.6 +/- 0.5 kcal/mol and 67.2 +/- 0.5 degrees C for ferricytochrome b562. The smaller heat capacity change upon unfolding of apocytochrome b562 than that of ferricytochrome b562, estimated from the thermodynamic parameters, indicates that apocytochrome b562 possesses a smaller hydrophobic core than holocytochrome b562. Size-exclusion chromatography studies indicate that the apoprotein is slightly more extended in molecular dimension than ferricytochrome b562. The data suggest that apocytochrome b562 resembles a "molten globule" or a "collapsed form" of the holoprotein, in which secondary structure formation is largely complete while the global folding is either only partially complete or dynamically expanded.

[Hepatic inflammatory pseudotumor. A report of 5 cases].

Hepatic inflammatory pseudotumor (HIP) is rare. To our knowledge, there have only been 27 cases reported since 1953. We studied additional five cases, male, aged 13-56 years, with a history of the disease of 20 days-1 year. Major complains were epigastric pain, fever of unknown causes, and epigastric mass. All five HIPs were solitary and surgically resected with a final diagnosis made pathologically. HIPs mimic the characters of liver cancer on ultrasonography and CT scanning, however, the following several points could be used to establish the diagnosis: patients with a long history of hepatic tumor still in a rather good condition; patients with no cirrhosis and negative AFP test results; tumors that are well encapsulated, etc. Surgical exploration should be attempted in all patients unless in those with poor risks in which steroid therapy may prove useful.

[Inhibition of PHA-stimulated T cell conditioned medium (PHA-TCM) on the growth of human myeloid progenitor cells (CFU-C)].

Cord blood T cells were enriched by nylon wool colomn, and effects of PHA-stimulated T cell supernatant collected from 18 h to 7 days on the proliferation of CFU-c were studied. The results showed that the supernatant collected at 18 h (PHA-TCM) could significantly inhibit the growth of CFU-c and the inhibition was PHA-TCM dose dependent, suggesting there is a CFU-c inhibitory activity in PHA-TCM. Kinetic studies demonstrated that the activity was decreased in the supernatant collected at 48 h and disappeared at 7 days. On the other hand, unstimulated T cell supernatant and PHA alone had no inhibitory effect on CFU-c growth. Indomethacin did not affect the production of the inhibitory activity and no interferon activity could be detected in PHA-TCM. These suggested that the inhibition was mediated by a non-interferon, non-prostaglandin suppressor. Further studies revealed that the suppressor was a protein stable at 56 degrees C and lost in pH 2 and pH 11 for 3 h, its molecular weight was large than 10,000 dolton.

[Effect of PHA-T cell conditioned medium (PHA-TCM) on leukemic cells].

Cord blood T cells, purified by nylon wool column, were incubated with PHA for 18 hours, and the supernatant were harvested as PHA-TCM. The results demonstrated that PHA-TCM could significantly inhibit the growth of U937 cells and reduce their 3H-TdR incorporation and spontaneous colony formation. After 3-6 days of treatment with PHA-TCM in culture, part of U937 cells became macrophage-like, latex-phagocytic, and capable of reducing NBT dye. On the contrary, HL-60 cells did not respond to PHA-TCM inhibition, indicating the selective effect of PHA-TCM.