MCL1 transgenic mice exhibit a high incidence of B-cell lymphoma manifested as a spectrum of histologic subtypes

Viability-promoting genes such as BCL2 play an important role in human cancer but do not directly cause aggressive tumors. BCL2 transgenic mice develop lymphoma at low frequency, hindering studies of tumorigenesis and its inhibition in the presence of such gene products. MCL1 is a member of the BCL2 family that is highly regulated endogenously and that promotes cell viability and immortalization when introduced exogenously. Mice expressing an MCL1 transgene in hematolymphoid tissues have now been monitored for an extended period and were found to develop lymphoma with long latency and at high probability (more than 85% over 2 years). In most cases, the disease was widely disseminated and of clonal B-cell origin. A variety of histologic subtypes were seen, prominently follicular lymphoma and diffuse large-cell lymphoma. MCL1 thus sets the stage for the development of lymphoma as does BCL2, disease occurring with high probability and recapitulating a spectrum of subtypes as seen in human patients. These findings with the transgene underscore the importance of the normal, highly regulated pattern of MCL1 expression, in addition to providing a model for studying tumorigenesis and its inhibition in the presence of a viability promoting BCL2 family member. (Blood. 2001;97:3902-3909)

Detection of abasic sites on individual DNA molecules using atomic force microscopy

We have developed an atomic force microscopy-based method for detecting abasic sites (AP sites) on individual DNA molecules. By using uracil and uracil DNA glycosylase, we first prepared a 250-bp DNA template consisting of two AP sites at specific locations. We then detected the AP sites by marking them with biotinylated aldehyde-reactive probes and monomeric avidin. We demonstrate here that (i) the location of monomeric avidin bound on a single DNA molecule was detectable by atomic force microscopy; (ii) the observed location of avidin was in good agreement to the predicted AP sites at a few nanometer resolution; and (iii) by end-labeling the 5'-terminus of one DNA strand, the AP sites were determined without directional ambiguity. The technique described here will provide a sensitive way of locating AP sites and contribute to screen DNA damages from individual molecules.

[Sequential intensified immunosuppressive therapy combining with hematopoietic growth factors in the treatment of severe aplastic anemia]

OBJECTIVE

To explore more effective regimen for reducing early mortality of severe aplastic anemia (SAA) and improving therapeutic effectiveness.

METHODS

Antilymphocyte globulin/antithymocyte globulin (ALG/ATG) and cyclosporine A (CsA) (sequential intensified immunosuppressive therapy, SIIST), with or without hematopoietic growth factors (HGFs) were administered to 73 SAA patients in a prospective randomized clinical trial to test the effectiveness of the addition of HGFs for the patients.

RESULTS

The response rate of SIIST with HGFs group was significantly higher than that of SIIST alone group (89.2% vs 63.9%), with lower rates of early infection (24.3% vs 55.3%) and mortality (4.0% vs 16.7%), shorter duration of cytopenia and blood transfusion dependence and faster recovery of bone marrow hematopoiesis. The addition of HGFs to SIIST was tolerated well in all patients. There was no difference in the treatment outcome of the two groups with GM-CSF plus Epo or G-CSF plus Epo.

CONCLUSION

The use of HGFs in combination with SIIST could reduce early infection and mortality rates and, therefore, improve the response rates in SAA patients.

[Dynamic monitoring of Ph positive cells during early post-transplant period in chronic granulocytic leukemia by interphase FISH]

OBJECTIVE

To assess the effectiveness of transplantation and observe the kinetics of residual leukemic cells during early post-transplantation period in chronic granulocytic leukemia (CGL).

METHODS

Ten normal controls, seven untreated CGL patients and eleven CGL patients after allogeneic bone marrow transplantation (allo-BMT) or peripheral blood stem cell transplantation (PBSCT) were studied by interphase fluorescence in situ hybridization (I-FISH) with the FITC fluorescein labeled BCR probe. Conventional cytogenetic analysis (CCA) and reverse transcriptase-polymerase chain reaction (RT-PCR) were also employed.

RESULTS

The normal cutoff was defined as less than 6.68% (x +/- 3s) from the analysis of normal controls. The reproduciblity of FISH method was confirmed by serial dilutions by mixing Ph positive cells and normal cells. Forty specimens from 11 CGL patients at 1 week to 6 years post-BMT were investigated after PBSCT and the results showed that (1) FISH and RT-PCR could accurately evaluate Ph (+) cells during early transplantation period (within one month), but RT-PCR was more sensitive in six months after BMT. (2) Residual Ph (+) cells tended to be linear decreasing with the time after transplantation and fell in normal range in most samples three months later. The mean time of normaligation was 57 days (20 to 170 days). (3) One case relapsed and received a second transplantation. FISH presented more precise data for predicting relapse as compared to CCA and RT-PCR.

CONCLUSIONS

I-FISH as a useful tool can not only offer more precise assessment of residual leukemic cells compared with CCA and RT-PCR, but also provide dynamic monitoring during early post-BMT period to evaluate the transplantation outcome and predict relapse.

[Observation of long-term therapeutic outcome in chronic granulocytic leukemia]

OBJECTIVE

To analyse the long-term outcome of various therapeutic protocol for the treatment of chronic granulocytic leukemia (CGL).

METHODS

Median duration of chronic phase, survival and transformation of 331 CGL patients treated with different project were retrospectively analyzed.

RESULT

Longer chronic phase and survival and lower percentage of transformation were found in patients using mesoindigo as maintaining treatment as compared with those using busulfan as maintaining treatment. The effect of meisoindigo and hydroxyurea showed no significant difference. These two drugs were both superior to bulsufan. Combination chemotherapy was not superior to meisoindigo, hydroxyurea or busulfan alone. Interferon had the best therapeutic effectiveness for the treatment of CGL.

CONCLUSION

Busulfan was not suitable for maintaining treatment. Meisoindigo or meisoindigo combined with hydroxyurea was good choices for maintaining treatment. Meisoindigo and hydroxyurea had better effect in combination than alone. Interferon could significantly prolong the chronic period and survival period of CGL patients.

[Immunorelated pancytopenia]

OBJECTIVE

A report of a group of patients with pancytopenia which might be related to abnormal immunity.

METHODS

The clinical and laboratory features of 29 patients with positive bone marrow mononuclear cell (BMMNC) Coombs tests were analyzed.

RESULTS

Most of these cases were pancytopenia with normal or decreased bone marrow cellularities and increased normoblasts. They were all found to have negative results of conventional hemolysis tests and hematopoietic nutrient determination and had no evidence of malignant clonal hematopoiesis. However, all of them showed positive BMMNC-Coombs test and good response to corticosteroids.

CONCLUSION

Immunorelated pancytopenia might be caused by abnormal immunity (especially autoantibody) mediated destruction or abnormal function of blood cells. It is beneficial to differentiate immunorelated pancytopenia from aplastic anemia or myelodysplastic syndromes.

[Change of NOS activity in hypoxia and cold-induced blood vessels damage and its biological significance]

OBJECTIVES

To explore the therapeutic methods for hypoxia and cold induced blood vessel damage by observing the changes of NO synthase (NOS) activity in hypoxia and development of coldm induced blood vessels damage, and studying the effects of SOD and vitamin C on the changes of NOS activity.

METHODS

The main artery was isolated from Wistar rats and exposed to hypoxia and/or cold environment in vitro. LDH activity was measured using an automatic biochemical analyzer and NOS and SOD activities in blood vessels were analyzed respectively by Griess assay and adrenaline autoxidantion method.

RESULTS

NOS activity in hypoxia, cold and hypoxia-cold damaged vessels decreased by 18.2%, 19.1% and 25.9% respectively after exposure as compared with the control vessels. The changes of NOS activity were time dependent. The NOS activity in damaged vessels was negatively correlated with LDH activity in the culture medium of the respective vessels. The SOD activity in hypoxia and/or cold damaged vessels also decreased significantly. Giving SOD (200 u/ml) or vitamin C (50 mg/ml) immediately after hypoxia and/or cold exposure increased the NOS activity and SOD activity in the damaged vessels significantly, as compared with the non-treatment controls.

CONCLUSIONS

The decrease of NOS activity is closely related to the development of damage induced by hypoxia and/or cold injury. SOD and vitamin C could protect the blood vessels exposed to hypoxia and/or cold from damage, possibly by increasing NOS activity.

[Multivariate analysis of prognostic factors in Philadelphia chromosome-positive chronic granulocytic leukemia]

OBJECTIVE

To investigate the prognostic factors of the patients with Philadelphia chromosome-positive chronic granulocytic leukemia (CGL).

METHODS

Clinical and laboratory parameters of 209 CGL patients at diagnosis were analyzed in relation to survival. COX regression analysis were used to identify the statistically significant prognostic factors.

RESULTS

The median survival time was 57 (3 - 179) months, and 5 year survival rate was 48%. From the COX regression model, the four main poor prognostic factors were as follows: percentage of bone marrow blasts (>or= 0.04), percentage of peripheral blood blasts and promyelocytes and presence of erythroid precursors in peripheral blood. According to the prognostic scores, three groups of CGL were identified. The low-risk group was with a median survival time of 76 months, the intermediate-risk group with 56 months, and the high-risk group with 31.5 months (P < 0.01). The 5 year survival rate was 70.42%, 46.30% and 18.18% (P < 0.01), respectively.

CONCLUSIONS

A prognostic scoring system suitable for Chinese CGL patients was proposed.

Thio- and oxoflavopiridols, cyclin-dependent kinase 1-selective inhibitors: synthesis and biological effects

Flavopiridol analogues, thio- and oxoflavopiridols which contain a sulfur (16) or oxygen (18) atom linker between a chromone ring and the hydrophobic side chain, are selective cyclin-dependent kinase 1 (CDK1) inhibitors with an IC(50) of 110 and 130 nM. These analogues were prepared from key intermediate 7 by substituting the ethyl sulfoxide. Enantio pure intermediate piperidone 10 was obtained from the racemic piperidone 8 via a very efficient "dynamic kinetic resolution" in 76% yield. Hydrophobic side chains such as chlorophenyl or tert-butyl produced potent CDK1 inhibitory activity, while hydrophilic side chains such as pyrimidine or aniline caused a severe reduction in CDK inhibitory activity. These analogues are competitive inhibitors with respect to ATP, and therefore activity was dependent upon the CDK subunit without being affected by the cyclin subunit or protein substrate. Thio- and oxoflavopiridols 16 and 18 are not only selective within the CDK family but also discriminated between unrelated serine/threonine and tyrosine protein kinases. CDK1 selective thio- and oxoflavopiridol analogues inhibit the colony-forming ability of multiple human tumor cell lines and possess a unique antiproliferative profile in comparison to flavopiridol.

[Clinicopathological studies on bone marrow involvement of non-Hodgkin's lymphoma]

OBJECTIVE

To investigate the relationship between pathomorphological features and clinical manifestations of non-Hodgkin's lymphoma (NHL) with bone marrow involvement (BMI).

METHODS

Plastic-embedded section of bone marrow biopsy was stained with H-Giemsa-E. Immunotyping of NHL was performed immunohistochemically.

RESULTS

A total of 70 patients with NHLBMI(male: 52, female: 18; median age: 49 years) was studied. There were 20 patients with T cell-lymphoma and 50 patients with B cell-lymphoma. The extent of bone marrow involvement was minimal in 15 cases, moderate in 16 cases and severe in 39 cases. Bone marrow involvement was of interstitial type in 23 cases, nodular type in 7 cases, and mixed type in 18 cases and diffuse type in 22 cases. The frequency of splenomegaly in nodular type NHLBMI was significantly higher than that in any other type. Nodular type NHLBMI occurred mainly in B cell-lymphoma. Lymphoma cell leukemia (LCL) developed in 14 of 39 (35.9%) cases of NHL with severe bone marrow involvement which was significantly more frequent than that in NHL with mild and moderate bone marrow involvement.

CONCLUSION

Difference in the extent and pattern of bone marrow involvement in NHL is related to clinical manifestations. Bone marrow biopsy helps evaluate response to treatment.

[Study on the clinical characteristics of biphenotypic acute leukemia]

OBJECTIVE

To analyze the biological characteristics and the treatment outcome of adult biphenotypic acute leukemia.

METHODS

Immunophenotypes were examined using indirect immunofluorescence method. Biphenotypic acute leukemia (BAL) was diagnosed according to EGIL scoring system.

RESULTS

(1) The incidence of BAL in acute leukemia was 3.4%. Percentage for coexpression of B lymphoid and myeloid antigens was 68.4%, for T lymphoid and myeloid antigens 21.1%, for B, T lymphoid and myeloid antigens 10.5%. (2) CD(34) was expressed in 43.75% of the BAL cases. (3) Cytogenetic analysis revealed normal and abnormal karyotypes in 41.7% and 58.3% of the BAL cases, respectively. (4) Six of 19 patients achieved completed remission (CR), but the disease free survivals were all less than 6 months. Treatment outcomes were negatively related to the expression of CD(34) antigen and cytogenetic findings. The BAL patients were poorly responded to therapeutic regimens directed to AML.

CONCLUSION

Coexpression of B/M antigens is the commonest subtype in BAL. BAL had a poor prognosis, especially treated with induction regimen directed to AML.

[In vitro induction of autologous T cell killing by heat treated human chronic myelogenous leukemia cells]

OBJECTIVE

To investigate the potential of autologous T cell killing of heat treated chronic myelogenous leukemia (CML) cells (autologous tumor killing, ATK).

METHODS

(51)Cr release assay was used to measure the ATK activity of autologous T cells against CML cells treated with 42 degrees C for 30 minutes (heat) or 37 degrees C for 30 minutes (non-heat). The phenotypes of T cells and heat shock protein 70 (HSP70) expression of CML cells were measured by flow cytometry (FCM). T cells from the CML patients were stimulated and expanded by autologous mixed lymphocyte/tumor cell cultures (MLTC).

RESULTS

ATK activity of autologous T cells to the non-heated and heated CML cells were found in 4 (19.05%) and 10 (47.62%) of the 21 cases, respectively. The ATK activity of interleukin-2 (IL-2) stimulated autologous T cells against heated CML cells was markedly higher than that of unstimulated autologous T cells against non-heated CML cells (P < 0.001). FCM analysis showed that no HSP70 was expressed on the CML cell membranes whether heated or non-heated, but intracellular HSP70 expressions were (83.42 +/- 5.65)% and (78.34 +/- 6.32)% pre- and post-heated, respectively. The phenotypes of T cells stimulated and expanded in MLTC were TCRgammadelta - CD(3)(+), mostly CD(8)(+), with some activation markers (CD(25) and HLA-DR) expression. The ATK activities of these T cells against the heated and non-heated CML cells and K562 cells were (51.25 +/- 4.26)%, (36.52 +/- 3.83)% and (2.92 +/- 1.19)%, respectively.

CONCLUSIONS

ATK activity of autologous T cells against CML cells could be induced or enhanced by heat treatment of the CML cells particularly of T cells stimulated with IL-2. This ATK activity was not associated with gammadelta T cells or HSP70 expression of CML cells.

Folate deficiency reduces the GPI-anchored folate-binding protein in rat renal tubules

A folate-binding protein (FBP) anchored to cell membranes by a glycosyl phosphatidylinositol (GPI) adduct is constitutively expressed in some transformed and cultured cell lines. Its expression is upregulated when these cells are grown in medium containing low folate, but whether this occurs in vivo with nutritional folate deficiency is unknown. To address this question, the GPI-FBP in the liver, kidney, and brain of rats on control and folate-deficient (FD) diets was measured. The GPI-FBP in the kidney of FD rats decreased significantly in contrast to the upregulation of this protein in cultured cells. Northern blot analysis and nuclear run-on assays indicated that transcription of the GPI-FBP gene in the kidney was not reduced by folate deficiency. This decrease of the GPI-FBP appears to result from its proteolysis, similar to the enzymatic degradation of the apoprotein that occurs in vitro. Because the GPI-FBP is on the brush borders of the proximal renal tubules and provides for the reabsorption of folate, this function diminishes when the protein decreases in folate deficiency.

[The genetic instability of mismatch repair gene linked microsatellite and the evolution of CML]

OBJECTIVE

To explore the relationship between the genetic instability of microsatellite linked with mismatch repair gene and the evolution of CML to blast crisis.

METHODS

The loss of heterozygosity (LOH) and microsatellite instability (MSI) of two polymorphic microsatellite markers, D2s123 and D3s1298, linked with mismatch repair gene hMSH2 and hMLH1 respectively, were detected by PCR-silver staining method on the bone marrow cells of 18 CML patients, who clinically progressed from the chronic phase to accelerated phase or blast crisis.

RESULTS

Differences in microsatellite D2s123 and D3s1298 at the CML accelerated phase or blast crisis in 5 (27.8%) of the 18 patients were demonstrated compared with chronic phase. For D2s123, MSI and LOH were observed in 1 of 8 patients with accelerated phase (12.5%) and 2 of 10 patients in blast crisis (20%). For D3s1298, MSI and LOH were observed in 2 of 10 patients in blast crisis (20%).

CONCLUSION

The genetic alteration of microsatellite D2s123 and D3s1298 may play a role in the progress of some CML cases.

[Detection of apoptosis by in situ labeling and study on the expression of PCNA in hypertrophic scars and keloids]

To investigate the involvement of apoptosis and proliferation in the lesions of hypertrophic scars and keloids, eighteen samples of hypertrophic scar and five samples of keloid were collected. The apoptosis was detected with terminal deoxynucleatidyl transferase mediated d-UTP biotin nick end labeling(TUNEL) and the expression of PCNA was assessed with immunohistochemical technique in scar lesions and normal skin. Results showed that in hypertrophic scar and keloid samples the rate of proliferating cells in dermis was higher than that of normal skin(P < 0.05), whereas the apoptosis index between scars and normal skin shows no statistical significance. It indicates that excessive proliferation and the lack of apoptosis of cells in dermis may cause the formation and development of hypertrophic scars and keloids.

Changes in local cerebral blood flow, glucose utilization, and mitochondrial function following traumatic brain injury in rats

The pathophysiology of secondary brain damage following experimental traumatic brain injury was investigated by measuring local cerebral blood flow (lCBF), local cerebral glucose utilization (lCGU), and activity of succinate dehydrogenase (SDH), which is a mitochondrial enzyme of the tricarboxylic acid cycle, in the rat brain after moderate lateral fluid percussion injury. Measurements used autoradiography for lCBF and lCGU with [14C]iodoantipyrine and [14C]2-deoxyglucose, respectively. Regional SDH activity was determined using quantitative imaging of formazan produced from 2,3,5-triphenyl tetrazolium chloride by SDH. lCBF decreased at 1 hour after injury and was significantly lower than the preinjury level in almost all regions of both hemispheres at 6 and 24 hours, and remained low at 2 weeks. lCGU increased 1 hour after injury but was significantly decreased at 6 and 24 hours, and at 2 weeks in most regions of both hemispheres. The ipsilateral hemisphere showed a significant decrease in the activity of SDH in the cortices, hippocampus, thalamus, and caudate/putamen, most conspicuously 72 hours after injury, whereas no significant decrease was observed in the contralateral hemisphere at any time. Necrosis in the injured cortex and reduction of the number of neurons in the ipsilateral hippocampus were observed 2 weeks after injury. The present study showed that a decrease in lCBF and mitochondrial dysfunction occur with glucose hypermetabolism around 1 hour after lateral fluid percussion injury, and that lCBF, lCGU, and mitochondrial function all deteriorate after 6 hours. This suggests that lCBF and cellular metabolism may change dynamically during the several hours following traumatic brain injury, and afterwards neuronal damage may result in an irreversible change in the areas with depressed glucose hypermetabolism in the early period after injury in combination with mitochondrial dysfunction.

Distension-induced myoelectrical dysrhythmia and effect of intestinal pacing in dogs

The aims of this study were to investigate the effect of duodenal distension on intestinal myoelectrical activity and to investigate whether intestinal pacing was able to reverse the effects of distension. Six female hound dogs with four pairs of electrodes on the proximal jejunum were involved in this study. The protocol consisted of 30 min of recording of jejunal myoelectrical activity as baseline and 90 min of recording during distension. Intestinal pacing was performed during the second 30 min of distension. Duodenal distension severely impaired intestinal myoelectrical activity. The percentage of normal slow waves was reduced from 90.8+/-8.4% at baseline to 73.8+/-10.2%, 57.2+/-11.4%, and 53.7+/-16.0% during the first, second and third 30 min of distension (P<0.05, ANOVA). The dominant power was similarly decreased and the minute-by-minute variation of dominant frequency was significantly increased after distension. Intestinal pacing reversed distension-induced dysrhythmia. The percentage of normal slow waves during the 30 min of distension with pacing was significantly higher than the corresponding 30 min of distension without pacing (88.5+/-6.6% vs. 57.2+/-11.4%, P<0.03). It was concluded that intestinal pacing can normalize distension-induced dysrhythmia and has a potential as a future therapeutic modality for intestinal motor disorders.

[Reversion of HBV-related liver fibrosis and early cirrhosis by baicao rougan capsule]

OBJECTIVE

To observe the therapeutic effect of herbal compound, Baicao Rougan Capsule on human liver fibrosis and early cirrhosis associated with chronic hepatitis B.

METHODS

Forty-two patients with liver fibrosis and 10 cases early cirrhosis were treated with a herbal compound for six months. Two liver biopsies were performed before and after treatment, their serum samples were collected before, in the middle of and after the treatment, all samples were measured at the same time.

RESULTS

Improvement of clinical symptoms and signs occurred in 75% to 91% of the patients, serum ALT lowered to normal level in 68%. The serum level of type IV collagen, laminin and hyaluronic acid were significantly reduced by the end of treatment (P < 0.05). Grading score was reduced from 7.79 +/- 6.15 to 5.36 +/- 3.95 after treatment (P < 0.05), while staging score was reduced from 7.39 +/- 5.55 to 5.26 +/- 4.36 (P < 0.05).

CONCLUSION

Chinese herbal compound Baicao Rougan Capsule is effective in the treatment, and in the reversal of HBV related liver fibrosis and early cirrhosis.

High-energy pulse compression by use of negative phase shifts produced by the cascade chi((2)):chi((2)) nonlinearity

We report a simple optical pulse-compression technique based on quadratic nonlinear media. Negative nonlinear phase shifts are generated by phase-mismatched second-harmonic generation, and the phase-modulated pulses are then compressed by propagation through materials with normal dispersion. Millijoule-energy pulses from a Ti:sapphire amplifier are compressed from 120 to 30 fs, and calculations indicate that compression ratios of >10 are realistically achievable by use of this approach with optimal materials. The insertion loss of the compressor can be less than 10% of the pulse energy, and scaling to higher pulse energies will be straightforward.

Cyclin D2 promoter disrupted by t(12;22)(p13;q11.2) during transformation of chronic lymphocytic leukaemia to non-Hodgkin's lymphoma

In a unique case of chronic lymphocytic leukaemia (CLL) we performed a longitudinal cytogenetic and molecular genetic study of tumour cells from diagnosis through progression and transformation to non-Hodgkin's lymphoma (NHL) and lymphomatous meningitis. CLL cells at diagnosis had trisomy 12 and a t(14;19)(q32;q13.3). At relapse, the leukaemic cells had a subclone carrying a t(12;22)(p13;q11.2) in addition to the initial changes. We cloned reciprocal translocation junctions at the 22q11.2- chromosome and the 12p13+ chromosome and the corresponding germline DNA fragments. Restriction map analysis and nucleotide sequence analysis of the cloned DNA fragment from the 22q11.2- chromosome mapped the translocation break within the immunoglobulin (Ig)-lambda-C complex at the nt3889; nts 3890, 3891 were lost from the translocation site. A probe from the 3'-end of the clone derived from the 22q11.2- chromosome showed single copy hybridization which was different from the Ig-lambda probe. Nucleotide sequence analysis of the exact junction region and the corresponding germline DNA showed that the translocation at 12p13 occurred in the negative regulatory region of the cyclin D2 gene at the nt -1602, and a pentamer consisting of nts -1603 to -1599 was lost at the break site. We sequenced another 227 bp upstream of the known 5'-end of the promoter and did not find any open reading frame. From these results we hypothesize that, in this patient, the t(12;22) disrupted the negative regulator in the promoter of cyclin D2 which in turn might have deregulated cyclin D2.

[Determination of trace selenium in spirulina by continuous-flow hydride generation atomic absorption spectrometry]

The mixed solutions of the hydrogenized element-NaOH-NaBH4 and HCI solution were fed into hydride vapor generator at the same rate by multi-flow peristaltic pump. Selenium element in the aqueous solution reacted on the nascent hydrogen to generate gaseous hydride. No separation was needed and the method was highly sensitive with little interference. The selenium content in spirulina was determined and a reliable analytical method was established. The determination limit of the method was 0.017 microg x g(-1), and the recovery of the samples was 98.89%-101.20%.

[Apoptosis inducing effect of meisoindigo on K562 cells]

OBJECTIVE

To study the effect of meisoindigo on human chronic myelogenous leukemia (CML) cell line K562 cells for exploring the mechanism of meisoindigo in treatment of CML.

METHODS

Multiple methods, including dose-response curve, trypan blue exclusion, cytomorphology, DNA electrophoresis, flow cytometry and TUNEL (TdT mediated dUTP nick and labeling), were used to observe the effect of meisoindigo on K562 cells.

RESULTS

Meisoindigo can inhibit the proliferation and induce the apoptosis of K562 cells.

CONCLUSION

The therapeutic mechanism of meisoindigo in treating CML may be related with its proliferation inhibiting and apoptosis inducing effect in CML cells.

Retrospective analysis of the Beijing family of Mycobacterium tuberculosis in preserved lung tissues

Direct repeat spoligotyping of 85 paraffin-embedded lung biopsies was used to investigated the occurrence around Beijing of the Beijing family of Mycobacterium tuberculosis. Samples ranged in time from 1956 to 1990. Hybridization patterns were found with 49 (58%) samples, and 45 (92%) produced typical Beijing family patterns extending over the 34-year period.

Normalization of atropine-induced postprandial dysrhythmias with gastric pacing

Gastric pacing has received increasing attention recently. However, few studies have systematically assessed the effect of pacing on gastric dysrhythmias. The aims of this study were to investigate the effect of gastric pacing on gastric dysrhythmia and to explore whether the effect of gastric pacing was mediated via cholinergic nerves. Eight hound dogs implanted with three pairs of serosal electrodes were studied. Three study sessions were performed on each dog. The experiment was conducted sequentially as follows: a 30-min myoelectrical recording immediately after a meal, intravenous injection of atropine or saline, and three sequential 20-min myoelectrical recordings with or without gastric pacing during the second 20-min recording. The percentage of regular slow waves (3.5-7. 0 cycles/min) was calculated using spectral analysis. The percentage of the regular slow waves was progressively reduced from 96.7 +/- 1. 7% at baseline to 29.6 +/- 9.0 (P < 0.001), 23.1 +/- 7.1 (P < 0.001), and 27.3 +/- 4.3% (P < 0.001), respectively, during the first, second, and third 20 min after atropine injection. Normalization of the gastric slow wave was achieved with gastric pacing 2.3 +/- 1.0 min after the initiation of pacing. The percentage of regular slow waves was significantly increased both during pacing (93.6 +/- 2.4 vs. 23.1 +/- 7.1%, P < 0.002) and after pacing (70.9 +/- 6.8 vs. 27. 3 +/- 4.3%, P < 0.003) in comparison with the session without pacing. We conclude that 1) atropine induces gastric myoelectric dysrhythmia in the fed state, 2) gastric pacing is able to normalize gastric postprandial dysrhythmia induced by atropine, and 3) the effect of gastric pacing is not mediated by vagal cholinergic mechanism.

The stability and fate of a spliced intron from vertebrate cells

Introns constitute most of the length of typical pre-mRNAs in vertebrate cells. Thus, the turnover rate of introns may significantly influence the availability of ribonucleotides and splicing factors for further rounds of transcription and RNA splicing, respectively. Given the importance of intron turnover, it is surprising that there have been no reports on the half-life of introns from higher eukaryotic cells. Here, we determined the stability of IVS1Cbeta1, the first intron from the constant region of the mouse T-cell receptor-beta, (TCR-beta) gene. Using a tetracycline (tet)-regulated promoter, we demonstrate that spliced IVS1Cbeta1 and its pre-mRNA had half-lives of 6.0+/-1.4 min and 3.7+/-1.0 min, respectively. We also examined the half-lives of these transcripts by using actinomycin D (Act.D). Act.D significantly stabilized IVS1Cbeta1 and its pre-mRNA, suggesting that Act.D not only blocks transcription but exerts rapid and direct posttranscriptional effects in the nucleus. We observed that in vivo spliced IVS1Cbeta1 accumulated predominantly as lariat molecules that use a consensus branchpoint nucleotide. The accumulation of IVS1Cbeta1 as a lariat did not result from an intrinsic inability to be debranched, as it could be debranched in vitro, albeit somewhat less efficiently than an adenovirus intron. Subcellular-fractionation and sucrose-gradient analyses showed that most spliced IVS1Cbeta1 lariats cofractionated with pre-mRNA, but not always with mRNA in the nucleus. Some IVS1Cbeta1 also appeared to be selectively exported to the cytoplasm, whereas TCR-beta pre-mRNA remained in the nucleus. This study constitutes the first detailed analysis of the stability and fate of a spliced nuclear intron in vivo.

Regulation of MCL1 through a serum response factor/Elk-1-mediated mechanism links expression of a viability-promoting member of the BCL2 family to the induction of hematopoietic cell differentiation

Proliferation, differentiation, and apoptosis are tightly regulated during hematopoiesis, allowing amplification along specific lineages while preventing excessive proliferation of immature cells. The MCL1 member of the BCL2 family is up-regulated during the induction of monocytic differentiation (approximately 10-fold with 12-O-tetradecanoylphorbol 13-acetate (TPA)). MCL1 has effects similar to those of BCL2, up-regulation promoting viability, but differs from BCL2 in its rapid inducibility and its pattern of expression. Nuclear factors that regulate MCL1 transcription have now been identified, extending the previous demonstration of signal transduction through mitogen-activated protein kinase. A 162-base pair segment of the human MCL1 5'-flank was found to direct luciferase reporter activity, allowing approximately 10-fold induction with TPA that was suppressible upon inhibition of the extracellular signal-regulated kinase (ERK) pathway. Serum response factor (SRF), Elk-1, and Sp1 bound to cognate sites within this segment, SRF and Elk-1 acting coordinately to affect both basal activity and TPA inducibility, whereas Sp1 affected basal activity only. Thus, the mechanism of the TPA-induced increase in MCL1 expression seen in myelomonocytic cells at early stages of differentiation involves signal transduction through ERKs and transcriptional activation through SRF/Elk-1. This finding provides a parallel to early response genes (e.g. c-FOS and EGR1) that affect maturation commitment in these cells and therefore suggests a means through which enhancement of cell viability may be linked to the induction of differentiation.

Effects of electroacupuncture on gastric migrating myoelectrical complex in dogs

The aim-of this study was to investigate the characteristics of the gastric slow wave during different phases of the migrating myoelectrical complex (MMC) and the effect of electroacupuncture on the MMC. The experiment was performed in eight hound dogs implanted with one pair of bipolar serosal electrodes 2 cm proximal to the pylorus. Gastric myoelectrical activity was recorded for three complete cycles of the MMC in two sessions, one with electroacupuncture at points ST36 and PC6 and the other at sham points. The acupuncture was performed for 30 min in phase I of the second cycle of the MMC. Spectral analysis was performed to compute the frequency and power (amplitude) of the gastric slow wave, whereas blind visual analysis was applied to compute the appearance of spike potentials and the length of each phase of the MMC. It was found that there was a significant difference in the frequency and power of the gastric slow wave during different phases of the MMC (P < 0.05). Phase I was characterized with the highest frequency and lowest power of the gastric slow wave, whereas phase III exhibited the highest power in the slow wave. It was also found that in comparison with the sham points, electroacupuncture at the acupoints increased the number of spike bursts. This increase was not significant during the MMC cycle with electroacupuncture (34.4+/-4.1 vs 27.5+/-2.5%, P > 0.05) but became significant during the cycle after electroacupuncture (39.8+/-3.3% vs 27.5+/-2.5%, P < 0.0005). Similarly, during the MMC cycle after electroacupuncture at the acupoints, there was a significant decrease in the length of phase I (14.8+/-2.2 vs 46.9+/-6.1 min, P < 0.003) and a significant increase in the length of phase II (75.6+/-9.9 vs 30.6+/-4.1 min, P < 0.003) and phase III (25.8+/-0.6 vs 22.1+/-0.7 min, P < 0.003). A similar increase was observed during the MMC cycle with electroacupuncture but was not statistically significant. In conclusion, the gastric slow wave has the highest power during phase III of the MMC, indicating that the antral contraction is characterized not only by the appearance of spikes, but also by the increased power of the slow wave. Electroacupuncture at acupoints of ST36 and PC6 enhances the gastric MMC by reducing the length of phase I and increasing the length of phases II and III.

CNI-1493 attenuates hemodynamic and pro-inflammatory responses to LPS

The increased production of pro-inflammatory cytokines and nitric oxide have been postulated to contribute to the deleterious sequella of LPS administration. To date, clinical strategies to control these responses using individual specific inhibitors have been disappointing. The aim of the present study was to determine whether a tetravalent guanylhydrazone compound (CNI-1493) attenuates LPS-induced stress responses by suppressing multiple inflammatory mediators. Rats were injected intravenously with either CNI-1493 (10 mg/kg) or vehicle (1 mL NaCl) 60 min prior to the injection of LPS (100 microg/100 g body weight). LPS produced a 20% decrease in mean arterial blood pressure and a significant increase in circulating TNF-alpha levels as well as in tissue content of TNF-alpha, IL-1beta, and IL-6. This was associated with a marked increase in lung and gut apoptosis and myeloperoxidase (MPO) activities as well as with an increase in lung and spleen nitric oxide end products (NOx). Pretreatment with CNI-1493 attenuated the LPS-induced drop in mean arterial blood pressure (MABP) and blunted (40%) the rise in circulating TNF-alpha levels. CNI-1493 attenuated the LPS-induced increase in tissue cytokine (TNF-alpha, IL-1beta, and IL-6) content in lung and spleen but did not alter that of liver or gut. CNI-1493 pretreatment protected both lung and gut from LPS-induced apoptosis and in addition attenuated the rise in MPO activity in the gut. These results suggest diverse effects of CNI-1493 that are tissue specific and that confer protection against the hemodynamic and inflammatory responses to LPS.

Mcl-1 in transgenic mice promotes survival in a spectrum of hematopoietic cell types and immortalization in the myeloid lineage

Mcl-1 is a member of the Bcl-2 family that is expressed in early monocyte differentiation and that can promote viability on transfection into immature myeloid cells. However, the effects of Mcl-1 are generally short lived compared with those of Bcl-2 and are not obvious in some transfectants. To further explore the effects of this gene, mice were produced that expressed Mcl-1 as a transgene in hematolymphoid tissues. The Mcl-1 transgene was found to cause moderate viability enhancement in a wide range of hematopoietic cell types, including lymphoid (B and T) as well as myeloid cells at both immature and mature stages of differentiation. However, enhanced hematopoietic capacity in transgenic bone marrow and spleen was not reflected in any change in pool sizes in the peripheral blood. In addition, among transgenic cells, mature T cells remained long lived compared with B cells and macrophages could live longer than either of these. Interestingly, when hematopoietic cells were maintained in tissue culture in the presence of interleukin-3, Mcl-1 enhanced the probability of outgrowth of continuously proliferating myeloid cell lines. Thus, Mcl-1 transgenic cells remained subject to normal in vivo homeostatic mechanisms controlling viable cell number, but these constraints could be overridden under specific conditions in vitro. Within the organism, Bcl-2 family members may act at "viability gates" along the differentiation continuum, functioning as part of a system for controlled hematopoietic cell amplification. Enforced expression of even a moderate viability-promoting member of this family such as Mcl-1, within a conducive intra- and extracellular environment in isolation from normal homeostatic constraints, can substantially increase the probability of cell immortalization.

Diode-Pumped Cr:forsterite Laser Mode Locked by a Semiconductor Saturable Absorber

We report the passive mode locking of a diode-pumped Cr:forsterite laser using a semiconductor saturable absorber. The laser generates 10-pJ pulses as short as 1.5 ps in duration with ~650 mW of absorbed pump power. We measured the transient reflectance of the saturable absorber mirror under different incident energy fluences by using a standard pump-probe method. The performance of this laser is also compared with a high-power fiber-laser-pumped femtosecond forsterite laser mode locked with the same absorber.

[Genetic instability of microsatellites Mfd41 and DCC in the evolution of chronic myelogenous leukemia]

OBJECTIVE

To explore the relationship between the genetic instability of microsatellite and the evolution of chronic myelogenous leukemia(CML).

METHODS

The loss of heterozygosity(LOH) and the microsatellite instability(MSI) of two polymorphic microsatellite markers, DCC and Mfd41, which located on chromosome 18q and 17p respectively, were assayed by standard PCR-silver staining analysis in bone marrow cells from 17 CML patients progressing from chronic phase to accelerated phase or blast crisis.

RESULTS

LOH or MSI of the two microsatellites were demonstrated in 8/17 (47.5%) patients in accelerated/blastic phases. For DCC, genetic instability was revealed in 2 of 9 patients in accelerated phase and in 4 of 8 in blast crisis. For Mfd41, genetic instability was revealed in 1 of 9 patients in accelerated and in 1 of 8 in blast crisis.

CONCLUSION

Genetic instability of DCC and Mfd41 may play a role in the evolution of CML.

[Virilizing and feminizing adrenal syndrome]

OBJECTIVE

To inquire into diagnosis, differential diagnosis and treatment of virilizing and feminizing adrenal syndrome especially differential diagnosis between benign and malignant of sex hormone producing adrenal neoplasma and treatment principles of congenital adrenal hyperplasia (CAH).

METHOD

Eight cases of CAH and five cases of sex hormone producing adrenal neoplasma were presented during 1986-1996. The former included 3 rare cases of 17 alpha hydroxylase deficiency and others. The latter included 3 cases of feminizing adrenal tumors and 2 cases of virilizing adrenal tumors.

RESULT

Weight and diameter of tumor, DHEA, 17-ks and sex hormone levels, appearance of CT imaging, infiltration and metastasis, were closely related to differentiation of benign and malignant tumors.

CONCLUSION

Some standards are not absolute because of limited practice, follow-up is very important. Adrenal virilizing and feminizing neoplasms were surgically resected by different incision. Modified subcostal incision is recommended as a best choice for huge adrenal mass. Corticoadrenal hormone treatment of CAH should select different kind of corticoadrenal medicine for different kind of CAH. Treatment of sex hormones is not suitable for children suffered from 17 hydroxylase deficiency until prepuberty.

[A study on the anti-metastatic effects of CD3Ak cells in nude mice]

OBJECTIVE

To investigate whether cancer draining lymph node lymphocytes activated by CD3 McAB in vitro have anti-tumor effects in vivo.

METHODS

Nude mice with highly metastatic human ovarian cancer were treated with CD3 McAB activated killer cells (CD3AK) from human ovarian cancer draining lymph node lymphocytes. 31 experimental nude mice were divided into 4 groups; the cisplatin group (7 mice), the CD3AK cells group (7 mice), the combined treatment group (7 mice), and control group (10 mice). Treatment began on the 10th day after tumor transplantation for a total of 80 days.

RESULTS

The transplanted tumors disappeared in 1 mouse of CD3AK group, significant difference in the anti-metastatic effect was found between the CD3AK group (2/7 mice with metastasis) and the control group (8/10 mice with metastasis). Significant difference in average tumor volume was found between the CD3AK group (0.5788 +/- 0.2549) and the control group (1.5685 +/- 0.283). The tumor growth inhibition rate reached 63.1% in the CD3AK group. Significant difference in the serum level of progesterone was found between the CD3AK group (3.3843 +/- 0.5314) and the control group (6.3480 +/- 0.7615). Significant difference in the histiocyte increase in the lymph node sinuses was found between the CD3AK group (59/69) and the control group (55/94).

CONCLUSION

These results suggest that CD3AK cells appear to be effective in tumor growth inhibition, anti-metastasis and enhancing host immunologic function.

Femtosecond Cr:forsterite laser diode pumped by a double-clad fiber

We present a compact, all-solid-state femtosecond Cr:forsterite laser. The laser is pumped by diodes through a double-clad fiber. Kerr-lens mode locking is initiated and stabilized by a semiconductor saturable-absorber mirror with a single InGaAs quantum well. This system generates transform-limited 80-fs pulses near 1.3microm . An average power of 68 mW with fluctuation of much less than 1% is obtained with 3.8 W of absorbed pump power. The stability, efficiency, compactness, and potential for scaling to higher power of this system make it an attractive short-pulse source for applications.

Immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications

OBJECTIVE

To explore the immunophenotype of myeloid cells in myelodysplastic syndyomes (MDS) and its clinical implications.

METHODS

A panel of monoclonal antibody was used to detect CD13+, CD33+, CD15+ and CD14+ antigens on the membrane surfaces of myeloid cells in the bone marrow from 51 MDS, 21 aplastic anemia (AA), 21 paroxysmal nocturnal hemoglobinuria (PNH) patients. 10 acute myeloblastic leukemia (AML) patients and 15 normal subjects by immunoenzymatic assay. The morphology and chromosome karyotype of bone marrow cells of MDS patients were also examined.

RESULTS

CD14+, CD13+ and CD33+ cells in the bone marrow were more in MDS patients than in normal controls, AA patients and PNH patients. CD15+ cells in the bone marrow were less in MDS patients than in normal controls.

CONCLUSIONS

The percentages of CD14+, CD13+ and CD33+ positive cells in the bone marrow of MDS patients were related to the percentage of myeloblasts, the chromosomal aberrations and the response to treatment. It indicated that there is immunophenotypic misexpression of myeloid cells in MDS patients. Immunophenotype analysis of myeloid cells might be useful for the diagnosis and treatment of MDS patients.

Cr:forsterite laser pumped by broad-area laser diodes

We report the demonstration of a Cr:forsterite laser pumped by broad-area laser diodes producing non-diffraction-limited beams. The use of a thin crystal to reduce losses at the lasing wavelength and of short-wavelength pump diodes reduces the lasing threshold to <500 mW .Relatively low output powers (5 mW) are obtained, but prospects for increasing the power and achieving mode-locked operation of this laser are good and are discussed.

Comparison of moyamoya disease in Japan and moyamoya disease (or syndrome) in the People's Republic of China

To find out the causes of many epidemiological differences in Moyamoya disease in Japan and in the People's Republic of China, we performed a bibliographical investigation and an actual survey and reached the following conclusions: (1) Leptospiral infection can cause Moyamoya syndrome which cannot be differentiated from Moyamoya disease unless confirmed through the patients past history and a positive serum test; and (2) Moyamoya disease reported in China may include Moyamoya syndrome caused by leptospiral or other cerebral arteritis.

A triple-head SPECT system with parallel-hole collimators of different acceptance angles

We proposed to use three different parallel-hole collimators for a triple-head SPECT system. One of the collimators had a small collimator acceptance angle to provide ultra-high spatial resolution and the other two had larger collimator acceptance angles to achieve high counts. A new 2D reconstruction algorithm that combined the data acquired from different collimators was derived to take advantages of both high resolution and high sensitivity. The algorithm was evaluated using a computer-simulated matrix of spherical sources. For noise-free data, the accuracy (mainly determined by spatial resolution) obtained from combination of the collimator acceptance angles of 1.35, 4.05 and 6.75 degrees (or 1.35, 5.40 and 9.45 degrees) was slightly inferior to that obtained from three same LEHR collimators (with a 2.70 degrees collimator acceptance angle). This is because the modulation transfer function (MTF) resulting from three different collimators decreases more quickly at low frequencies but becomes comparable at high frequencies as compared with the MTF of the 2.70 degrees collimator. With noisy data, however, the image quality obtained with three different collimators was better than that resulting from any combinations of three same collimators. The improvement was only achieved by using the derived algorithm, while the conventional FBP algorithm did not improve image quality even with the same collimator configuration.

[Studies on expansion ex vivo of murine bone marrow cells and its hematopoietic reconstitution capacity]

OBJECTIVE

To investigate the effects of stem cell factor (SCF) in combination with interleukin-1 (IL-1) or/and interleukin-3 (IL-3) on ex vivo expansion of 5FU treated bone marrow cells and hematopoietic recovery in lethally irradiated mice transplanted with the expanded cells.

METHODS

5FU treated bone marrow cells (d3-5FU-BMC) were cultured in a cytokines-containing medium, and the net increments of CFU-GM and high proliferative potential colony forming cell (HPP-CFC) were evaluated.

RESULTS

CFU-GM increased by 33.7 +/- 18.1- or 18.1 +/- 6.3- fold, and HPP-CFC by 17.8 +/- 10.5- or 12.7 +/- 9.1- fold, respectively, in cultures containing SCF with IL- or IL-3, as compared with that in control; while SCF alone had little effect. Compared with fresh d3-5FU-BMC, transplantation of the expanded bone marrow cells accelerated the recovery of recipients' peripheral blood cell counts by 1 approximately 3 days and increased the survival rate of the transplanted animals (d3-5FU-BMC group 50% vs expansion group 8U approximately 100%).

CONCLUSION

SCF in combination with IL-1 or IL-3 synergetically ex vivo expands hematopoietic cells. Transplantation of the expanded bone marrow cells accelerates the recipient's hematopoietic reconstitution.

Compensation for displacement of the focal point in cone beam single photon emission computed tomography reconstruction

This study examined the effects of focal point displacement on image quality in cone beam single photon emission computed tomography (SPECT). A new image reconstruction algorithm that accounts for the focal point shift was derived and three shift geometries were investigated. The geometries included a lateral shift with a fixed focal length but off-center focusing, a linear axial shift with a variable focal length that depends linearly on the distance between a bin of the detector and the center of the detector, and a random axial shift with a randomly varying focal length. Computer simulation was conducted to evaluate the shift effects with a phantom that was composed of 118 small spherical sources. The results demonstrated that the lateral shift of the focal point was more critical to image quality than was the axial shift. With a 0.64 cm (1 pixel) lateral shift, noticeable artifacts was observed, while an axial shift resulted in minimal changes in image quality until it reached 8 cm (12.5 pixels). The derived reconstruction algorithm eliminated most of the artifacts caused by a fixed lateral shift or a linear axial shift of the focal point, but failed to do so for a random axial shift since the linear distribution assumed in image reconstruction did not match the random shift occurred in acquisition of the data.

[In vitro study on the effects of the novel retinoids on the proliferation and differentiation of normal and leukemic cells]

OBJECTIVE

To evaluate the prospect for clinical use of four novel retinoid compounds (retinoid 1, retinoid 2, retinoid 3 and retinoid 4), which were different structurally from all-trans retinoic acid.

METHODS

The effects of the four retinoids on the differentiation and clonal proliferation of NB4 cells and fresh acute promyelocytic leukemia (APL) cells and on the proliferation of normal hematopoietic cells were studied. Cell morphological examination,nitro tetrazolium blue reduction test, cell cycle dynamics, and colony formation assay were used in the study.

RESULTS

Novel retinoids induced differentiation of NB4 and fresh APL cells, and markedly inhibited CFU-L growth of NB4 and fresh APL cells. The activity related to their chemical structures and retinoid 2 was more active. The novel retinoids enhanced the growth of CFU-GM, CFU-E and CFU--Meg of normal bone marrow cells.

CONCLUSION

These novel retinoids, especially retinoid 2, may regulate the proliferation and differentiation of normal hematopoiesis, induce APL cell differentiation and maturation, and are worthy of further study for clinical use.

[Study on the immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications]

OBJECTIVE

To explore the immunophenotype of myeloid cells in myelodysplastic syndromes and its clinical implications.

METHODS

A panel of monoclonal antibodies was used to detect CD13, CD33, CD15 and CD14 on the membrane surfaces of myeloid cells in the bone marrow from 51 patients with myelodysplastic syndromes (MDS), 21 with aplastic anemia (AA), 21 with paroxysmal nocturnal hemoglobinuria (PNH), and 15 normal subjects, by immunoenzymatic assay. The morphology and chromosome karyotype of bone marrow cells of MDS patients were also examined.

RESULTS

CD14+ cells, CD13+ cells and CD33+ cells in the bone marrow were more in MDS patients than in normal controls, AA patients and PNH patients. CD15+ cells in the bone marrow were less in MDS patients than in normal controls. The percentages of CD14, CD13 and CD33 positive cells in the bone marrow of MDS patients were related to the percentage of myeloblast, the chromosomal aberrations and the response to treatment.

CONCLUSION

There was an immunophenotypic misexpression of myeloid cells in MDS patients. Immunophenotype analysis of myeloid cells might be useful for the diagnosis and directing treatment in MDS patients.

Mcl-1, a Bcl-2 family member, delays the death of hematopoietic cells under a variety of apoptosis-inducing conditions

Mcl-1 is a member of the Bcl-2 family that was identified based on increased expression in myeloblastic leukemia cells undergoing differentiation. Mcl-1 was previously found to be similar to Bcl-2 in causing a delay in apoptotic cell death in Chinese hamster ovary cells. The work described here was aimed at determining whether Mcl-1 could also exert such an effect in hematopoietic cells, because endogenous Mcl-1 expression is prominent in the hematopoietic system. A further aim was to assess the effects of Mcl-1 in cells exposed to a variety of cytotoxic stimuli, because Bcl-2 is known to have a broad spectrum of activity. To approach these aims, FDC-P1 murine myeloid progenitor cells were transfected with vectors driving either constitutive or inducible expression of Mcl-1. The introduced Mcl-1 gene was found to cause a prolongation of viability under various conditions that cause apoptotic cell death, including exposure to cytotoxic agents (the chemotherapeutic drug etoposide, calcium ionophore, or UV irradiation) and the withdrawal of required growth factors. In addition, Mcl-1 was found to interact with Bax, a member of the Bcl-2 family that promotes cell death as a homodimer but that can heterodimerize with Bcl-2 to promote cell viability. Although Mcl-1 prolonged cell viability, it did not prevent eventual cell death upon continuous exposure to a cytotoxic agent. Prolongation of viability was maximal when expression of Mcl-1 was induced before the application of the apoptotic stimulus, although some increase occurred if Mcl-1 was induced shortly thereafter and before overt apoptosis. Taken as a whole, these findings provide further parallels between Mcl-1 and Bcl-2, showing that Mcl-1 can interact with Bax in hematopoietic FDC-P1 cells and can prolong cell viability under a variety of cytotoxic conditions.

Picosecond carrier lifetime and large optical nonlinearities in InGaAsP grown by He-plasma-assisted molecular beam epitaxy

We report the measurement of a fast carrier lifetime and large band-gap-resonant optical nonlinearities in an InGaAsP sample grown by He-plasma-assisted molecular beam epitaxy. Using a 2-microm-thick sample grown on an InP substrate, we observed a carrier lifetime of 15 ps and an index change as large as 0.077 induced by an intense 1-ps pulse at a wavelength of 1.57 microm. Good crystalline structure is maintained in the material during growth, and the absorption spectrum shows a sharp band edge. These properties indicate that materials produced by He-plasma-assisted growth have potential applications in compact ultrafast photonic devices.

Early organ-specific hemorrhage-induced increases in tissue cytokine content: associated neurohormonal and opioid alterations

Hemorrhage is associated with an impairment in the immune response and with increased concentrations of circulating inflammatory cytokines. The present study determined the time course and localization of alterations in circulating and tissue pro-inflammatory cytokines (TNF-alpha, IL-1-alpha and -beta) in response to fixed-pressure (40 mm Hg) hemorrhage as well as the associated hanges in circulating neurohormonal and opioid mediators. Conscious unrestrained non-heparinized male Sprague-Dawley rats (n = 24) underwent hemorrhage followed by standard resuscitation with lactated Ringer's solution. Animals were sacrificed at three time points; immediately after the hemorrhage period, at completion of resuscitation and 1.5 h after the resuscitation period. Hemorrhage resulted in marked elevations in circulating levels of TNF-alpha, which averaged 860 +/- 201 pg/ml. The levels were similarly elevated following fluid resuscitation (877 +/- 196 pg/ml) and had decreased towards baseline 1.5 h after completion of resuscitation (281 +/- 134 pg/ml). TNF-alpha was not detectable in plasma of time-matched controls. Hemorrhage elevated TNF-alpha content in spleen (25%), lung (55%) and heart (20%), and tissue content remained elevated despite resuscitation. No significant changes in tissue content of TNF-alpha were detected in the liver, kidney or brain. Circulating levels of IL1-alpha and -beta were not detectable in either the time-matched controls or hemorrhaged animals. However, statistically significant elevations in tissue content of IL-1 alpha were observed in heart, spleen, lung, gut and whole brain (15-30%). Tissue content of IL-1 beta did not change in response to hemorrhage and/or fluid resuscitation. Activation of sympathetic outflow, as evidenced by a 3- to 4-fold elevation in circulating epinephrine and norepinephrine levels, was observed immediately after hemorrhage, and was associated with a 5-fold rise in circulating beta-endorphin. These results demonstrate an early increase in tissue cytokine content following hemorrhagic shock, which is associated with elevations in circulating catecholamines and endogenous opioids, consistent with their potential modulatory role in this response.

Alterations of level of total genomic DNA methylation and pattern of c-myc, c-Ha-ras oncogene methylation in human gastric carcinogenesis

OBJECTIVE

To investigate the status of DNA methylation in gastric carcinogenesis.

METHODS

We analysed methylation pattern of c-myc, c-Ha-ras oncogenes by southern blot hybridization. DNA from cancerous, paracancerous and non-cancerous area of surgically resected samples in 21 cases of advanced gastric cancer were digested with MspI/HpaII and hybridized with the two genomic 32P labelled probes. In addition, the level of total genomic DNA methylation was measured by incubating DNA with 3H-S-Adenosylmethionine (3H-SAM) in the presence of a methylase which methylates all the cytosine residues that are in the double CpG (cytosine-guanine).

RESULTS

The results indicated that both c-myc and c-Ha-ras oncogene fragments containing CCGG sequence were hypomethylated in DNA samples from cancerous (10/21 and 5/10) and paracancerous (13/21 and 4/10) areas. Moreover, the level of total genomic DNA methylation in cancerous tissue was significantly lower than that in non-cancerous and paracancerous mucosa tissues (P < 0.05). The results from two methods are incompletely alike.

CONCLUSION

These results supported a strong correlation between DNA hypomethylation and gastric carcinogenesis, particularly methylated pattern of c-myc and c-Ha-ras oncogenes fragments containing CCGG sequence was abnormal in gastric mucosa tissue from gastric cancerous and paracancerous areas.