Genomic landscape and chronological reconstruction of driver events in multiple myeloma

The multiple myeloma (MM) genome is heterogeneous and evolves through preclinical and post-diagnosis phases. Here we report a catalog and hierarchy of driver lesions using sequences from 67 MM genomes serially collected from 30 patients together with public exome datasets. Bayesian clustering defines at least 7 genomic subgroups with distinct sets of co-operating events. Focusing on whole genome sequencing data, complex structural events emerge as major drivers, including chromothripsis and a novel replication-based mechanism of templated insertions, which typically occur early. Hyperdiploidy also occurs early, with individual trisomies often acquired in different chronological windows during evolution, and with a preferred order of acquisition. Conversely, positively selected point mutations, whole genome duplication and chromoplexy events occur in later disease phases. Thus, initiating driver events, drawn from a limited repertoire of structural and numerical chromosomal changes, shape preferred trajectories of evolution that are biologically relevant but heterogeneous across patients.

Genomic patterns of progression in smoldering multiple myeloma

We analyzed whole genomes of unique paired samples from smoldering multiple myeloma (SMM) patients progressing to multiple myeloma (MM). We report that the genomic landscape, including mutational profile and structural rearrangements at the smoldering stage is very similar to MM. Paired sample analysis shows two different patterns of progression: a "static progression model", where the subclonal architecture is retained as the disease progressed to MM suggesting that progression solely reflects the time needed to accumulate a sufficient disease burden; and a "spontaneous evolution model", where a change in the subclonal composition is observed. We also observe that activation-induced cytidine deaminase plays a major role in shaping the mutational landscape of early subclinical phases, while progression is driven by APOBEC cytidine deaminases. These results provide a unique insight into myelomagenesis with potential implications for the definition of smoldering disease and timing of treatment initiation.

Targeting proteasome ubiquitin receptor Rpn13 in multiple myeloma

Proteasome inhibitor bortezomib is an effective therapy for relapsed and newly diagnosed multiple myeloma (MM); however, dose-limiting toxicities and the development of resistance can limit its long-term utility. Recent research has focused on targeting ubiquitin receptors upstream of 20S proteasome, with the aim of generating less toxic therapies. Here we show that 19S proteasome-associated ubiquitin receptor Rpn13 is more highly expressed in MM cells than in normal plasma cells. Rpn13-siRNA (small interfering RNA) decreases MM cell viability. A novel agent RA190 targets Rpn13 and inhibits proteasome function, without blocking the proteasome activity or the 19S deubiquitylating activity. CRISPR/Cas9 Rpn13-knockout demonstrates that RA190-induced activity is dependent on Rpn13. RA190 decreases viability in MM cell lines and patient MM cells, inhibits proliferation of MM cells even in the presence of bone marrow stroma and overcomes bortezomib resistance. Anti-MM activity of RA190 is associated with induction of caspase-dependent apoptosis and unfolded protein response-related apoptosis. MM xenograft model studies show that RA190 is well tolerated, inhibits tumor growth and prolongs survival. Combining RA190 with bortezomib, lenalidomide or pomalidomide induces synergistic anti-MM activity. Our preclinical data validates targeting Rpn13 to overcome bortezomib resistance, and provides the framework for clinical evaluation of Rpn13 inhibitors, alone or in combination, to improve patient outcome in MM.

An update on imatinib mesylate therapy in chronic myeloid leukaemia patients in a teaching hospital in Malaysia

INTRODUCTION

The introduction of imatinib mesylate in 1998 has changed the management of chronic myeloid leukaemia. It is now the first-line therapy for newly diagnosed chronic myeloid leukaemia patients worldwide. However, its long-term survival benefit still needs to be established in clinical setting among Asian patients.

METHODS

All chronic myeloid leukaemia patients in the chronic phase who were on imatinib mesylate therapy were retrospectively reviewed. Data was collected through a review of case notes, which was then processed, managed and analysed.

RESULTS

A total of 44 patients were included in the study. The cumulative rates of complete haematological response, major cytogenetic response and major molecular response were 93.2%, 75.0% and 34.2%, respectively. The overall survival and event-free survival at five years were 86.0% and 84.9%, respectively. 31.8% of the patients developed anaemia, 29.5% neutropenia and 27.3% thrombocytopenia. A total of 43.2% of patients developed non-haematological side effects. Higher dosage (> 600 mg) and smaller body size (< 60 kg) were risk factors for haematological side effects. Patients with major cytogenetic response and absence of thrombocytopenia had better survival.

CONCLUSION

The majority of our chronic myeloid leukaemia patients did well with imatinib therapy. The adverse effects in our patients were tolerable, and no patient had to stop treatment permanently.

Long-term low-dose amiodarone therapy in the management of ventricular and supraventricular tachyarrhythmias: efficacy and safety

BACKGROUND

Amiodarone hydrochloride has been in use for two decades for the control of ventricular and supraventricular arrhythmias. Established and emerging evidence indicates that amiodarone has an antiarrhythmic efficacy superior to that of most other drugs.

HYPOTHESIS

The study was undertaken to evaluate the efficacy and acceptability of low-dose amiodarone therapy in the long-term management of supraventricular and ventricular tachyarrhythmias.

METHODS

A total of 124 patients with symptomatic drug-refractory or life-threatening arrhythmias managed with low-dose oral amiodarone therapy over a 10-year period was analyzed retrospectively. Of these, 45 patients (36%) had ventricular arrhythmias, 52 (42%) had atrial arrhythmias, and 27 (22%) had atrioventricular reentry tachycardia. Loading doses of amiodarone 600 mg daily for 1 week were administered for supraventricular arrhythmias and 600-1200 mg daily for 2 weeks for ventricular arrhythmias. Maintenance daily doses were 194 +/- 48 and 206 +/- 55 mg, respectively. Mean treatment duration was 32 +/- 28 months, with 326.3 patient years of therapy.

RESULTS

Of 39 patients with sustained ventricular tachyarrhythmias, the actuarial incidence of satisfactory arrhythmia control (absence of sudden cardiac death or nonfatal arrhythmia recurrence) was 78% at 1 year and 71% at 2 years. Satisfactory control of supraventricular arrhythmias (mean ventricular rate < 100/min with significant symptomatic improvement for sustained atrial arrhythmias and < 1 attack per year for paroxysmal atrial or atrioventricular arrhythmias) was achieved in 73, 65, and 62% of patients at 1, 2, and 3 years, respectively. The cumulative incidence of amiodarone-related adverse effects was 5.8 per 100 patient years, with drug withdrawal required in 12 patients (9.7%). Fifteen patients had thyroid dysfunction, 2 had hepatic toxicity, and 1 developed nonfatal pulmonary fibrosis. Overall, the incidence of successful use of amiodarone (satisfactory arrhythmia control and freedom from side effects) was 67, 59, and 53% at 1, 2, and 3 years, respectively.

CONCLUSIONS

The results of this study suggest that the efficacy of low-dose amiodarone therapy in the management of serious ventricular and supraventricular arrhythmias would be similar to those achieved with higher doses, but with a much more acceptable side effect profile.

Specific killing of multiple myeloma cells by (-)-epigallocatechin-3-gallate extracted from green tea: biologic activity and therapeutic implications

Epigallocatechin-3-gallate (EGCG), a polyphenol extracted from green tea, is an antioxidant with chemopreventive and chemotherapeutic actions. Based on its ability to modulate growth factor-mediated cell proliferation, we evaluated its efficacy in multiple myeloma (MM). EGCG induced both dose- and time-dependent growth arrest and subsequent apoptotic cell death in MM cell lines including IL-6-dependent cells and primary patient cells, without significant effect on the growth of peripheral blood mononuclear cells (PBMCs) and normal fibroblasts. Treatment with EGCG also led to significant apoptosis in human myeloma cells grown as tumors in SCID mice. EGCG interacts with the 67-kDa laminin receptor 1 (LR1), which is significantly elevated in myeloma cell lines and patient samples relative to normal PBMCs. RNAi-mediated inhibition of LR1 resulted in abrogation of EGCG-induced apoptosis in myeloma cells, indicating that LR1 plays an important role in mediating EGCG activity in MM while sparing PBMCs. Evaluation of changes in gene expression profile indicates that EGCG treatment activates distinct pathways of growth arrest and apoptosis in MM cells by inducing the expression of death-associated protein kinase 2, the initiators and mediators of death receptor-dependent apoptosis (Fas ligand, Fas, and caspase 4), p53-like proteins (p73, p63), positive regulators of apoptosis and NF-kappaB activation (CARD10, CARD14), and cyclin-dependent kinase inhibitors (p16 and p18). Expression of related genes at the protein level were also confirmed by Western blot analysis. These data demonstrate potent and specific antimyeloma activity of EGCG and provide the rationale for its clinical evaluation.

The bortezomib/proteasome inhibitor PS-341 and triterpenoid CDDO-Im induce synergistic anti-multiple myeloma (MM) activity and overcome bortezomib resistance

The synthetic triterpenoid 2-cyano-3, 12-dioxooleana-1, 9-dien-28-oic acid (CDDO) induces apoptosis in leukemic cells. Here we show that CDDO and its new derivative CDDO-imidazolide (CDDO-Im) trigger apoptosis in multiple myeloma (MM) cells resistant to conventional therapies including melphalan (LR-5), doxorubicin (Dox-40), and dexamethasone (MM.1R, U266, RPMI 8226) without affecting the viability of normal cells. CDDO-IM also triggers apoptosis in bone marrow stromal cells (BMSCs) and decreases interleukin-6 (IL-6) secretion induced by MM cell adhesion to BMSCs. Moreover, CDDO-Im-induced apoptosis in MM cells is not blocked by IL-6 or insulin growth factor-1 (IGF-1). Importantly, CDDO-Im and bortezomib/proteasome inhibitor PS-341 trigger synergistic apoptosis in MM cells associated with loss of mitochondrial membrane potential, superoxide generation, release of mitochondrial proteins cytochrome c/second mitochondria-derived activator of caspases (cytochrome c/Smac), and activation of caspase-8, -9, and -3. Conversely, the pancaspase inhibitor Z-VAD-fmk abrogates the CDDO-Im + bortezomib-induced apoptosis. Low doses of CDDO-Im and bortezomib overcome the cytoprotective effects of antiapoptotic proteins Bcl2 and heat shock protein-27 (Hsp27) as well as nuclear factor-kappa B (NF-kappaB)-mediated growth/survival and drug resistance. Finally, combining CDDO-Im and bortezomib induces apoptosis even in bortezomib-resistant MM patient cells. Together, these findings provide the framework for clinical evaluation of CDDO-Im, either alone or in combination with bortezomib, to overcome drug resistance and improve patient outcome in MM.

Hsp27 inhibits release of mitochondrial protein Smac in multiple myeloma cells and confers dexamethasone resistance

Smac, second mitochondria-derived activator of caspases, promotes apoptosis via activation of caspases. Heat shock protein 27 (Hsp27) negatively regulates another mitochondrial protein, cytochrome c, during apoptosis; however, the role of Hsp27 in modulating Smac release is unknown. Here we show that Hsp27 is overexpressed in both dexamethasone (Dex)-resistant multiple myeloma (MM) cell lines (MM.1R, U266, RPMI-8226) and primary patient cells. Blocking Hsp27 by an antisense (AS) strategy restores the apoptotic response to Dex in Dex-resistant MM cells by triggering the release of mitochondrial protein Smac, followed by activation of caspase-9 and caspase-3. Moreover, AS-Hsp27 overcomes interleukin-6 (IL-6)-mediated protection against Dex-induced apoptosis. These data demonstrate that Hsp27 inhibits the release of Smac, and thereby confers Dex resistance in MM cells.

beta-lapachone, a novel plant product, overcomes drug resistance in human multiple myeloma cells

OBJECTIVE

To evaluate the anti-tumor potential of beta-lapachone in multiple myeloma (MM) cell lines (U266, RPMI8226, and MM.1S); MM cell lines resistant to dexamethasone (MM.1R), melphalan (RPMI8226/LR5), doxorubicin (RPMI8226/DOX40), and mitoxantrone (RPMI8226/ MR20); and MM cells from patients (MM1-MM4).

MATERIALS AND METHODS

Cytotoxicity of beta-lapachone was assessed by MTT and [3H]-thymidine uptake assays. Apoptosis was analyzed using propidium iodide staining, DNA fragmentation, TUNEL assay, caspase-9 colorimetric assay, and immunoblotting for caspase-3, poly (ADP-ribose) polymerase (PARP), and caspase-8 cleavage products. Paracrine growth of MM cells was assessed by [3H]-thymidine uptake in cultures of bone marrow stromal cells (BMSCs) and MM cells. Interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) secretion in the culture supernatants was measured by specific enzyme-linked immunosorbent assays (ELISAs).

RESULTS

beta-lapachone showed significant cytotoxicity in MM cells (IC(50): 4-8 microM). In contrast, normal peripheral blood mononuclear cells (PBMCs) and BMSCs from MM patients were relatively resistant (IC(50): 8-16 microM). IL-6 did not protect against beta-lapachone-induced apoptosis in MM.1S cells, and dexamethasone showed additive cytotoxicity. beta-lapachone also decreased binding of MM.1S cells to BMSCs; abrogated IL-6 and VEGF secretion triggered by adhesion of BMSCs to MM.1S cells; reduced proliferation of MM.1S cells adherent to BMSCs; and decreased intracellular adhesion molecule-1 (ICAM-1) expression on MM.1S cells. Furthermore, beta-lapachone induced typical PARP cleavage, increased caspase-9 proteolytic activity, and activation of caspase-3, without activation of caspase-8 in U266 cells.

CONCLUSION

These studies provide a framework for clinical evaluation of beta-lapachone to improve the outcome for patients with MM.

Regional specification of rodent and human neurospheres

Neural precursor cells were isolated from various regions of the developing rat and human brain and grown in culture as aggregates termed neurospheres. We asked whether cells within human and rodent neurospheres are identical, or whether they have species specific characteristics or differences based on their region of origin. Under our culture conditions, rodent neurospheres isolated from the cortex (ctxNS) and striatum (strNS) grew faster than those from the mesencephalon (mesNS), but stopped growing after only eight to ten population doublings. In contrast, human neurospheres under identical culture conditions, continued to grow for over 40 population doublings. Following migration and differentiation of both rodent and human cultures, ctxNS and strNS generated high numbers of small neurons whereas mesNS generated small numbers of large neurons with many long fibres. Only very rare neurons from mesNS expressed dopaminergic markers, and thus may require further signals to fully mature. While the rat neurospheres generated high numbers of oligodendrocytes, very few were found to develop from human neurospheres from any region after a few weeks of passaging. FACS analysis revealed a unique population of smaller cells within human strNS and ctxNS, which appeared to be neuronal progenitors. However, large cells within neurospheres were capable of generating these small neuronal progenitors following further proliferation. Together, our data show that rat and human neurospheres have unique characteristics with regard to growth and differentiation, and that the majority of precursor cells within neurospheres are regionally specified to generate set numbers of neurons. These findings have important implications for understanding the nature of proliferating neural precursors isolated from the developing CNS, and their potential for brain repair.

Adherence of multiple myeloma cells to bone marrow stromal cells upregulates vascular endothelial growth factor secretion: therapeutic applications

Increased angiogenesis has recently been recognized in active multiple myeloma (MM). Since vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are two key mediators of angiogenesis, we characterized the production of VEGF, b-FGF and interleukin-6 (IL-6) (a MM growth and survival factor) in MM cell lines and Epstein-Barr virus (EBV) transformed B cell lines from MM patients, patient MM cells, as well as bone marrow stromal cells (BMSCs) from normal healthy donors and MM patients. We detected secretion of VEGF, but no bFGF and IL-6, in MM cell lines (MM.1S, RPMI 8226 and U266); EBV transformed B cell lines from MM patients (IM-9, HS-Sultan and ARH77); MM cell lines resistant to doxorubicin (RPMI-DOX40), mitoxantrone (RPMI-MR20), melphalan (RPMI-LR5) and dexamethasone (MM.1R); and patient MM cells (MM1 and MM2). BMSCs from MM patients and normal donors secreted VEGF, b-FGF and IL-6. Importantly, when MM cells were adhered to BMSCs, there was a significant increase in VEGF (1.5- to 3.1-fold) and IL-6 (1.9- to 56-fold) secretion. In contrast, the bFGF decreased in co-cultures of BMSCs and MM cells. Paraformaldehyde fixation of BMSCs or MM cells prior to adhesion revealed that VEGF was produced both from BMSCs and MM cells, though it may come primarily from BMSCs in some cultures. IL-6 was produced exclusively in BMSCs, rather than MM cells. Moreover, when MM cells were placed in Transwell insert chambers to allow their juxtaposition to BMSCs without cell to cell contact, induction of VEGF and IL-6 secretion persisted, suggesting the importance of humoral factors. Addition of exogenous IL-6 (10 ng/ml) increased VEGF secretion by BMSCs. Conversely, VEGF (100 ng/ml) significantly increased IL-6 secretion by BMSCs. Moreover, anti-human VEGF (1 microg/ml) and anti-human IL-6 (10 microg/ml) neutralizing antibodies reduced IL-6 and VEGF secretion, respectively, in cultures of BMSCs alone and co-cultures of BMSCs and MM cells. Finally, thalidomide (100 microM) and its immunomodulatory analog IMiD1-CC4047 (1 microM) decreased the upregulation of IL-6 and VEGF secretion in cultures of BMSCs, MM cells and co-cultures of BMSCs with MM cells. These data demonstrate the importance of stromal-MM cell interactions in regulating VEGF and IL-6 secretion, and suggest additional mechanisms whereby thalidomide and IMiD1-CC4047 act against MM cells in the BM millieu.

Vascular endothelial growth factor triggers signaling cascades mediating multiple myeloma cell growth and migration

Multiple myeloma (MM) remains incurable, with a median survival of 3 to 4 years. This study shows direct effects of vascular endothelial growth factor (VEGF) upon MM and plasma cell leukemia (PCL) cells. The results indicate that VEGF triggers tumor cell proliferation via a protein kinase C (PKC)-independent Raf-1-MEK-extracellular signal-regulated protein kinase pathway, and migration via a PKC-dependent pathway. These observations provide the framework for novel therapeutic strategies targeting VEGF signaling cascades in MM.

Thalidomide and immunomodulatory derivatives augment natural killer cell cytotoxicity in multiple myeloma

The antiangiogenic activity of thalidomide (Thal), coupled with an increase in bone marrow angiogenesis in multiple myeloma (MM), provided the rationale for the use of Thal in MM. Previously, the direct anti-MM activity of Thal and its analogues (immunomodulatory drugs, IMiDs) on MM cells was demonstrated, suggesting multiple mechanisms of action. In this study, the potential immunomodulatory effects of Thal/IMiDs in MM were examined. It was demonstrated that Thal/IMiDs do not induce T-cell proliferation alone but act as costimulators to trigger proliferation of anti-CD3-stimulated T cells from patients with MM, accompanied by an increase in interferon-gamma and IL-2 secretion. However, an increase in autologous T-cell killing of patient MM cells could not be demonstrated. A role for natural killer (NK)- and LAK-cell-mediated killing is suggested because IL-2-primed peripheral blood mononuclear cells (PBMCs) treated with Thal/IMiDs demonstrated significantly increased lysis of MM cell lines. Cold target inhibition assays suggested NK- rather than LAK-cell-mediated killing. Furthermore, this killing was not major histocompatibility complex-class restricted, and the depletion of CD56(+) cells blocked the drug-induced MM cell lysis. It was significant that increased killing of patient MM cells by autologous PBMCs treated with Thal/IMiDs was also observed. Although the in vivo relevance of NK-cell-mediated MM cell killing is unknown, phenotypic analysis performed in MM patients receiving Thal therapy demonstrated an increase in CD3(-)CD56(+) cells in patients responding to therapy. Thus in vitro and in vivo data support the hypothesis that Thal may mediate its anti-MM effect, at least in part, by modulating NK cell number and function.

Study of propofol in bovine aortic endothelium: I. Inhibitory effect on bradykinin-induced intracellular calcium immobilization

BACKGROUND

Propofol has been found to affect the intracellular calcium concentration with clinical manifestations of hypotension and bradycardia. The purpose of this study is to examine the effect of propofol on intracellular calcium immobilization in bovine aortic endothelium under the stimulation of bradykinin.

METHODS

In order to validate the effect of propofol on the alteration of intracellular calcium concentration, we used the cultured bovine endothelial cells (Gm 7372a) to measure the calcium immobilization within the cells preincubated with or without propofol of clinical concentration. Using Fluo-3 staining and a fluorescence spectrophotometer (confocal microscope), intracellular calcium immobilization was demonstrated by the appearance of "hot spots" within the cytoplasm and perinuclear regions after addition of bradykinin to the cells. The changes of fluorescence density measured within these areas versus the effect of time were analyzed and compared with the cells in control group.

RESULTS

After addition of bradykinin, intracellular calcium hot spots increased dramatically within seconds and reached a maximal level within 20 seconds. The concentrations of calcium gradually decreased to a constant level after about 3 min following the addition of bradykinin to the cells. With pretreatment of propofol at 0.01 mM and 37 degrees C for 30 min, the immobilization of intracellular calcium from the intracellular stores were significantly inhibited that was demonstrated by the decreased appearance of hot spots when compared with control.

CONCLUSIONS

Our data demonstrated that under the stimulation of bradykinin, propofol at 0.01 mM, could inhibit intracellular calcium release from the intracellular stores in bovine aortic endothelial cells. This phenomenon might explain the possible mechanism for the clinical manifestations of hypotension and/or bradycardia associated with propofol.

Ku86 variant expression and function in multiple myeloma cells is associated with increased sensitivity to DNA damage

Ku is a heterodimer of Ku70 and Ku86 that binds to double-stranded DNA breaks (DSBs), activates the catalytic subunit (DNA-PKcs) when DNA is bound, and is essential in DSB repair and V(D)J recombination. Given that abnormalities in Ig gene rearrangement and DNA damage repair are hallmarks of multiple myeloma (MM) cells, we have characterized Ku expression and function in human MM cells. Tumor cells (CD38(+)CD45RA(-)) from 12 of 14 (86%) patients preferentially express a 69-kDa variant of Ku86 (Ku86v). Immunoblotting of whole cell extracts (WCE) from MM patients shows reactivity with Abs targeting Ku86 N terminus (S10B1) but no reactivity with Abs targeting Ku86 C terminus (111), suggesting that Ku86v has a truncated C terminus. EMSA confirmed a truncated C terminus in Ku86v and further demonstrated that Ku86v in MM cells had decreased Ku-DNA end binding activity. Ku86 forms complexes with DNA-PKcs and activates kinase activity, but Ku86v neither binds DNA-PKcs nor activates kinase activity. Furthermore, MM cells with Ku86v have increased sensitivity to irradiation, mitomycin C, and bleomycin compared with patient MM cells or normal bone marrow donor cells with Ku86. Therefore, this study suggests that Ku86v in MM cells may account for decreased DNA repair and increased sensitivity to radiation and chemotherapeutic agents, whereas Ku86 in MM cells confers resistance to DNA damaging agents. Coupled with a recent report that Ku86 activity correlates with resistance to radiation and chemotherapy, these results have implications for the potential role of Ku86 as a novel therapeutic target.

Elevated soluble MUC1 levels and decreased anti-MUC1 antibody levels in patients with multiple myeloma

Soluble MUC1 (sMUC1) levels are elevated in many MUC1(+) cancers. We and others have shown that MUC1 is expressed on multiple myeloma (MM) plasma cells and B cells. In this study, we measured sMUC1 levels in bone marrow (BM) plasma from 71 MM patients and 21 healthy donors (HDs), and in peripheral blood (PB) plasma from 42 MM patients and 13 HDs using an immunoassay that detects the CA27.29 epitope of MUC1. sMUC1 levels were found to be significantly greater (mean 31.76 U/mL, range 5.69 to 142.48 U/mL) in MM patient BM plasma versus HD BM plasma (mean 9.68 U/mL, range 0.65 to 39.83 U/mL) (P <. 001). Importantly, BM plasma sMUC1 levels were related to tumor burden because sMUC1 levels were significantly higher for MM patients with active disease (34.62 U/mL, range 5.69 to 142.48 U/mL) versus MM patients with minimal residual disease (16.16 U/mL, range 5.7 to 56.68 U/mL) (P =.0026). sMUC1 levels were also elevated in the PB plasma of MM patients (32.79 U/mL, range 4.15 to 148.84 U/mL) versus HDs (18.47 U/mL, range 8.84 to 42.49) (P =.0052). Lastly, circulating immunglobulin M (IgM) and IgG antibodies to MUC1 were measured in 114 MM patients and 31 HDs, because natural antibodies to MUC1 have been detected in patients with other MUC1-bearing malignancies. These studies demonstrated lower levels of circulating IgM (P <.001) and IgG (P =.078) antibodies to MUC1 in MM patients compared with HDs. Our data therefore show that in MM patients, sMUC1 levels are elevated and correlate with disease burden, whereas anti-MUC1 antibody levels are decreased.

Thalidomide and its analogs overcome drug resistance of human multiple myeloma cells to conventional therapy

Although thalidomide (Thal) was initially used to treat multiple myeloma (MM) because of its known antiangiogenic effects, the mechanism of its anti-MM activity is unclear. These studies demonstrate clinical activity of Thal against MM that is refractory to conventional therapy and delineate mechanisms of anti-tumor activity of Thal and its potent analogs (immunomodulatory drugs [IMiDs]). Importantly, these agents act directly, by inducing apoptosis or G1 growth arrest, in MM cell lines and in patient MM cells that are resistant to melphalan, doxorubicin, and dexamethasone (Dex). Moreover, Thal and the IMiDs enhance the anti-MM activity of Dex and, conversely, are inhibited by interleukin 6. As for Dex, apoptotic signaling triggered by Thal and the IMiDs is associated with activation of related adhesion focal tyrosine kinase. These studies establish the framework for the development and testing of Thal and the IMiDs in a new treatment paradigm to target both the tumor cell and the microenvironment, overcome classical drug resistance, and achieve improved outcome in this presently incurable disease.

SHP2 mediates the protective effect of interleukin-6 against dexamethasone-induced apoptosis in multiple myeloma cells

Our previous studies have shown that activation of a related adhesion focal tyrosine kinase (RAFTK) (also known as Pyk2) is required for dexamethasone (Dex)-induced apoptosis in multiple myeloma (MM) cells and that human interleukin-6 (IL-6), a known growth and survival factor for MM cells, blocks both RAFTK activation and apoptosis induced by Dex. However, the mechanism whereby IL-6 inhibits Dex-induced apoptosis is undefined. In this study, we demonstrate that protein-tyrosine phosphatase SHP2 mediates this protective effect. We show that IL-6 triggers selective activation of SHP2 and its association with RAFTK in Dex-treated MM cells. SHP2 interacts with RAFTK through a region other than its Src homology 2 domains. We demonstrate that RAFTK is a direct substrate of SHP2 both in vitro and in vivo, and that Tyr(906) in the C-terminal domain of RAFTK mediates its interaction with SHP2. Moreover, overexpression of dominant negative SHP2 blocked the protective effect of IL-6 against Dex-induced apoptosis. These findings demonstrate that SHP2 mediates the anti-apoptotic effect of IL-6 and suggest SHP2 as a novel therapeutic target in MM.

Propofol inhibits renal cytochrome P450 activity and enflurane defluorination in vitro in hamsters

PURPOSE

To determine the effect of propofol on renal cytochrome P450 activity and defluorination of enflurane.

METHODS

Renal microsomes were prepared by homogenization and differential centrifugation from pooled hamster kidneys. Defluorination of enflurane was assessed by measuring free fluoride metabolites after reacting enflurane with renal microsomes incubated with various concentrations, 0.05 - 1.0 mmol x L(-1) propofol in the NADPH-generating system. Drug metabolizing activities of renal cytochrome P450 mono-oxygenase enzymes were evaluated within microsomes preincubated with propofol and reacted with the specific marker substrates, aniline, benzo(a)pyrene, erythromycin and pentoxyresorufin, for cytochrome P450 2E1, 1A1, 3A4 and 2B1, respectively.

RESULTS

Renal defluorination of enflurane was inhibited by clinical concentrations, 0.05 mmol x L(-1) of propofol (P < 0.05). Dose-dependent inhibition of defluorination, aniline and benzo(a)pyrene hydroxylase within kidney microsomes was related to propofol concentration. Propofol demonstrated a profound inhibition of renal pentoxyresorufin dealkylase activity even at low concentrations, 0.05 mmol x L(-1) (P < 0.01). Propofol did not exhibit inhibition of erythromycin N-demethylation of kidney microsomes except at high concentration, 1.0 mmol x L(-1). Spectral analyses of key coenzymes of renal cytochrome P450 monooxygenase, cytochrome b5 and cytochrome c reductase, demonstrated an inhibition when incubated with high concentrations of propofol (P < 0.05).

CONCLUSION

In an in vitro study in an NADPH-generating system of hamster kidney microsomes, propofol, in clinical concentrations, exhibited a broad-spectrum of inhibition to renal monooxygenase activities and enflurane defluorination.

Modulation of cytochrome P450-dependent monooxygenases in streptozotocin-induced diabetic hamster: II. Reverse role of insulin in P450 activity and defluorination

BACKGROUND

Metabolic activities of cytochrome (cyt) P450-dependent monooxygenase could be modulated by diabetic state in experimental diabetic animals. The purpose of this study is to validate the effect of insulin on the modulation of the metabolic activity of cyt P450 and the defluorination ability to inhalational anesthetics in diabetic animals.

METHODS

Diabetic state in golden Syrian hamsters was achieved by intraperitoneal injection of streptozotocin 40 mg/kg once a day for 4 days. After stabilization of diabetic state for 6 weeks, a regimen of insulin treatment given subcutaneously was carried out. Metabolic activities of cyt P450 were assessed by the reaction with benzo(a) pyrene, pentoxyresorufin, aniline and erythromycin (specific substrates). The metabolic activities of cyt 1A1, 2B1, 2E1 and 3A4 respectively in a NADPH-generating system in microsomal preparations of the diabetic hamsters were observed before and after insulin treatment, and were compared with the control group. The ability of defluorination was evaluated by measuring the free fluoride metabolites after incubating the microsomes with enflurane in diabetic and insulin-treated hamsters. Contents of cyt P450 isozymes were measured by electrophoresis and immunoblotting before and after insulin treatment. Pathological features of hepatocytes in diabetic hamsters were evaluated microscopically before and after insulin treatment.

RESULTS

The defluorination of enflurane and activity of aniline hydroxylase (cyt 2E1) were successfully induced by diabetic state (P < 0.01). The pentoxyresorufin O-dealkylase (cyt 2B1) was inhibited nearly 50% in the diabetic hamster liver when compared with that of control (P < 0.01). While the activities of benzo(a)pyrene hydroxylase (cyt 1A1) and the erythromycin N-demethylase (cyt 3A4) were basically unaffected by diabetes, alterations in content of cyt P450 were parallel to the alterations in enzyme activities. Microscopically, diabetes induced vacuolization with fatty droplets in the hepatocytes. After treatment with insulin injection, the enzyme activities, protein content and pathologic features returned to the baseline similar to the control.

CONCLUSIONS

Our data demonstrated that under diabetic state, metabolic activities of cyt P450 and its extent of defluorination would be polymorphically modulated. After administration of insulin, the activities of cyt P450 and defluorination of enflurane returned to baseline as the blood sugar level had been normalized. This could remind the clinicians of the importance of insulin treatment in the potential drug-to-drug interactions in the diabetic patients.

Kaposi's sarcoma-associated herpesvirus gene sequences are detectable at low copy number in primary amyloidosis

Primary amyloidosis (AL), like multiple myeloma (MM), results from a clonal proliferation of plasma cells. Recent detection of Kaposi's sarcoma-associated herpesvirus (KSHV) gene sequences in MM patients, although controversial, suggested that KSHV may also be present in AL. In the present study, we assayed for KSHV gene sequences in patients with primary AL independently in 2 laboratories. Nested polymerase chain reaction (PCR) was performed on DNA isolated from 21 bone marrow (BM) core biopsy samples to amplify orf26 and orf72, 2 regions of the KSHV genome. Eighteen of 21 (86%) BM core biopsy samples were KSHV PCR positive. BM aspirates from 16 of these 21 AL patients were cultured for 4-6 weeks to generate long term bone marrow stromal cells (LT-BMSCs), and 13 of 16 (81%) LT-BMSCs were also KSHV PCR positive. Results in all but 1 sample were consistent in the 2 laboratories. Sequencing of the PCR products in the 2 laboratories confirmed 94-98% and 95-98% homology to the published orf 26 and orf 72 KSHV gene sequences respectively, with interpatient base pair differences. Despite the presence of KSHV gene sequences, only 4/18 (22%) KSHV PCR positive patients demonstrated KSHV lytic antibodies by immunoblot assay. A sensitive assay performed on the BCBL-1 cell line confirmed the presence of KSHV at a very low copy number in AL. PCR using patient specific light chain gene primers also amplified DNA isolated from 2 AL BM core biopsies and 3 AL LT-BMSCs which were KSHV PCR positive, suggesting the presence of clonotypic cells. Our results therefore demonstrate KSHV gene sequences albeit at a very low copy number in the majority of BM core biopsies and LT-BMSCs from AL patients, and serological responses in only a minority of cases. Ongoing studies to identify viral transcripts and gene products will determine the biological relevance of KSHV in AL disease pathogenesis.

Effects of propofol on functional activities of hepatic and extrahepatic conjugation enzyme systems

The effect of propofol on the hepatic and extrahepatic conjugation enzyme systems was assessed in vitro using microsomal and cytosolic preparations of human liver, hamster kidney, lung and gut. The functional activities of phase-II enzymes, including uridine diphosphate-glucuronosyltransferase (UDPGT), glutathione S-transferase (GST) and N-acetyltransferase (NAT) were evaluated in the presence of various concentrations of propofol (0.05-1.0 mmol litre-1), using 1-naphthol, 1-chloro-2,4-dinitrobenzene and p-aminobenzoic acid as substrates respectively. Propofol produced concentration-dependent inhibition of UDPGT activity in human liver microsomes. Propofol did not produce significant inhibition of human hepatic GST activity at concentrations below 1.0 mmol litre-1. In contrast, NAT activity was unaffected by propofol 0.05-1.0 mmol litre-1 in human liver cytosolic preparations. In extrahepatic tissues, hamster renal and intestinal UDPGT activities were significantly inhibited by propofol at 0.25-1.0 mmol litre-1. In these tissues, GST and NAT were unaffected by propofol at 1.0 mmol litre-1. Propofol produced differential inhibition of human liver and hamster extrahepatic conjugation enzymes as a result of different substrate and tissue specificities. The potential interference of the metabolic profile of phase-II enzymes as a result of inhibition by propofol (especially of UDPGT and GST) should be considered when using propofol with other drugs for anaesthesia.

Characterization of signaling cascades triggered by human interleukin-6 versus Kaposi's sarcoma-associated herpes virus-encoded viral interleukin 6

Kaposi's sarcoma-associated herpes virus (KSHV) is associated with Kaposi's sarcoma, multicentric Castleman's disease, and body cavity-based lymphomas, settings in which human interleukin-6 (hIL-6) acts as a growth factor. The KSHV open reading frame K2 encodes for viral IL-6 (vIL-6), a protein with 25% amino acid identity to hIL-6, which can promote the growth of hIL-6-dependent cell lines. In the present study, we characterized biological sequelae and signaling cascades triggered by hIL-6 versus vIL-6 in the hIL-6-dependent MH60 and B9 cell lines. Both hIL-6 and vIL-6 induced significant increases (P < 0.01) in DNA synthesis in these cell lines in a dose-dependent fashion. Neutralizing anti-hIL-6 antibody (Ab) inhibited DNA synthesis triggered by hIL-6, without similarly affecting proliferation in response to vIL-6. On the other hand, antimouse IL-6 receptor (mIL-6R) Ab blocked response to vIL-6, but not that to hIL-6. Both hIL-6 and vIL-6 activated gp130, Janus kinase 1, signal transducers and activators of transcription-3, and mitogen-activated protein kinase in both MH60 and B9 cells. Proliferation of these cell lines in response to both hIL-6 and vIL-6 was blocked by PD98059, an inhibitor of MEK1 activation. These data suggest that MEK1 activation mediates the proliferative response to both cytokines. Finally, both hIL-6 and vIL-6 also maintained viability of serum-starved MH60 and B9 cells and blocked dexamethasone-induced apoptosis of MM.1S human myeloma cells. Further characterization of the signaling cascades mediating the growth and antiapoptotic effects of vIL-6 versus hIL-6 may help identify their unique roles in disease pathogenesis in Kaposi's sarcoma and other KSHV-associated neoplasms.

Modulation of cytochrome P-450 dependent monooxygenases in streptozotocin-induced diabetic hamster: I. Effects of propofol on defluorination and cytochrome P-450 activities

BACKGROUND

Diabetes mellitus could induce polymorphic alterations of metabolic activities of cytochrome P-450 dependent monooxygenases in chemical-induced diabetic animals. The purpose of this study is to define the functional impact of clinical concentrations of propofol on the metabolic activities of cytochrome P-450 in the diabetic animals.

METHODS

In order to validate the effect of propofol on cytochrome P-450 activities, especially the cytochrome P-450 2E1 and its defluorination activity, we applied NADPH-generating system to measure the metabolizing activities of cytochrome P-450 isozymes of streptozotocin-induced diabetic hamsters within the microsomes preincubated with various concentrations of propofol. The extent of defluorination and activity of cytochrome P-450 2E1 were assessed by reacting the propofol-treated microsomes in NADPH-generating system with enflurane and aniline as substrates respectively. Drug metabolizing activities of cytochrome 1A1, 2B1, and 3A4 were evaluated by metabolizing specific substrates, benzo(a)pyrene, pentoxyresorufin and erythromycin, within the microsomes of diabetic hamsters preincubated with various concentrations of propofol.

RESULTS

The hepatic and renal defluorination of enflurane was significantly inhibited by 0.05 and 0.10 mM propofol in the microsomes of diabetic hamster (P < 0.05). The activities of aniline hydroxylase (cytochrome 2E1), pentoxyresorufin O-dealkylase (cytochrome 2B1) and benzo(a)pyrene hydroxylase (cytochrome 1A1) were inhibited by propofol in a concentration-dependent manner from 0.05 to 0.10 mM. However, propofol showed no significant effect to the erythromycin N-demethylase (cytochrome 3A4) at its concentration of 0.05-0.10 mM in the diabetic hamsters.

CONCLUSIONS

Our data demonstrated that propofol in therapeutic concentrations of 0.05 and 0.10 mM, could inhibit both liver and kidney defluorination and cytochrome P-450's activities of the diabetic hamsters in vitro of different extent. This should remind clinicians of propofol's potential drug-to-drug interactions in the diabetic patients.

Isolation and characterization of human multiple myeloma cell enriched populations

We developed a simple and rapid method to enrich tumor cells within bone marrow (BM) aspirates from patients with multiple myeloma (MM). Thirty patients with a median of 50% (8-85%) MM cells by morphology and 55% (6--85%) MM cells identified by CD38+CD45-cell surface phenotype were studied. BM mononuclear cells (BMMCs) were isolated by Ficoll Hypaque sedimentation and incubated with a cocktail of mouse monoclonal antibodies (mAbs) directed against CD3 (T cells); CD11b and CD14 (monocytes); CD33 (myeloid cells), CD45 and CD45RA (leucocyte common antigen); CD32 as well as glycophorin A. After the addition of anti-mouse Fc Ig-coated immunomagnetic beads, mAb-bound cells were removed in a magnetic field. The residual cell populations were enriched for MM cells, evidenced by >95% plasma cell morphology and >95% CD38+CD45RA-cell surface phenotype. Since this method requires only two short incubations, cell losses were minimal and the yield of MM cells was therefore high (>95%). Viability of the MM-cell enriched fractions was 99%, and these cells were functional in assays of proliferation, cell cycle analysis and immunoglobulin secretion. This immunomagnetic bead depletion method therefore permits the ready isolation of homogeneous populations of patient MM cells for use in both cellular and molecular studies.

CD40 activation mediates p53-dependent cell cycle regulation in human multiple myeloma cell lines

It has been reported that the activation of multiple myeloma (MM) cells by CD40 induces proliferation, growth arrest, and apoptosis. To determine whether the biologic sequelae of CD40 activation in MM cells depends on p53 function, we identified temperature-sensitive p53 mutations in the RPMI 8226 (tsp53E285K) and the HS Sultan (tsp53Y163H) MM cell lines. These cells were then used as a model system of inducible wtp53-like function because wild-type-like p53 is induced at permissive (30 degrees C) but not at restrictive (37 degrees C) temperatures. Using p21-luciferase reporter assays, we confirmed that CD40 induces p53 transactivation in RPMI 8226 and HS Sultan cells cultured under permissive, but not restrictive, conditions. Furthermore, CD40 activation of these MM cells under permissive, but not restrictive, temperatures increased the expression of p53 and p21 mRNA and protein. Importantly, CD40 activation induced the proliferation of RPMI 8226 and HS Sultan cells at restrictive temperatures and growth arrest and increased subG1 phase cells at permissive temperatures. These data confirmed that CD40 activation might have distinct biologic sequelae in MM cells, depending on their p53 status.

In vivo cytotoxicity of ovarian cancer cells through tumor-selective expression of the BAX gene

The BAX proapoptotic protein is capable of inducing cell death either directly, through its effects on mitochondrial function, or indirectly, by lowering the apoptotic threshold in response to certain chemotherapy agents. In this study, we tested the hypothesis that selective expression of BAX in human ovarian cancer through adenoviral gene transfer might represent a novel approach to eradicating tumor cells in vivo. Two constructs were prepared using replication-deficient adenoviral vectors containing either the cDNA for beta-galactosidase (Ad.DF3.betaGAL) or hemagglutinin (HA)-tagged BAX (Ad.DF3.BAX) under the control of the DF3 promoter. The DF3 promoter was used to confer tumor-specific gene expression in view of its restricted pattern of expression in the majority of human ovarian cancers and its limited expression in normal peritoneal mesothelial cells. In vitro infection of up to seven different epithelial cancer cell lines with Ad.DF3.betaGAL or Ad.DF3.BAX resulted in expression of either beta-galactosidase activity or HA-BAX protein, respectively, which was highly correlated with DF3 levels. Furthermore, infection with Ad.DF3.BAX was capable of highly selective cytotoxicity of DF3-positive ovarian cancer clonogenic cells in vitro. The effect of i.p. administration of Ad.DF3.BAX was also assessed in nude mice inoculated with the DF3-positive 36M2 human ovarian cancer cell line. Expression of either beta-galactosidase activity (after Ad.DF3.betaGAL treatment) or HA-BAX transcripts (after Ad.DF3.BAX treatment) was restricted to tumor tissue in vivo. Importantly, administration of Ad.DF3.BAX on days 2 and 3 after tumor inoculation was capable of eradicating >99% of tumor implants. These results demonstrate the feasibility of tumor selective expression of a proapoptotic protein such as BAX through adenoviral gene transfer.

Functional interaction between retinoblastoma protein and stress-activated protein kinase in multiple myeloma cells

Previous studies have demonstrated that gamma-irradiation (IR)-induced apoptosis in multiple myeloma (MM) is associated with activation of stress-activated protein kinase (SAPK). In the present study, we examined the molecules downstream of SAPK/C-Jun N-terminal kinase (JNK), focusing on the role of retinoblastoma protein (Rb) during IR-induced MM cell apoptosis. The results demonstrate that IR activates SAPK/JNK, which associates with Rb both in vivo and in vitro. Far Western blot analysis confirms that SAPK/JNK binds directly to Rb. IR-activated SAPK/JNK phosphorylates Rb, and deletion of the phosphorylation site in the COOH terminus domain of Rb abrogates phosphorylation of Rb by SAPK/JNK. Taken together, our results suggest that Rb is a target protein of SAPK/JNK and that the association of SAPK/JNK and Rb mediates IR-induced apoptosis in MM cells.

HELLP syndrome with antepartum pulmonary edema--a case report

A 44-year-old pregnant female with a gestation of 29 weeks suddenly developed abdominal pain, nausea, vomiting, and laboratory study showed anemia, elevated liver enzymes, and lower platelets. HELLP syndrome was diagnosed and urgent delivery was needed. In order to correct the plasma volume and platelet deficiency, 6 units of both fresh frozen plasma and platelets, were given before operation. However, acute pulmonary edema was noted in the antepartum period. After vigorous treatment, she gave birth to a male infant. The postoperative course was smooth and she and her baby were discharged eleven days later. This case reminded us once again of the importance and necessity of invasive monitoring in fluid management of these patients.

A prospective study of elective stenting in unprotected left main coronary disease

The standard treatment of left main coronary artery (LMCA) disease has been bypass surgery (CABG). Recent reports suggested that stenting of LMCA disease might be feasible. From January 1995 to April 1998, we carried out a prospective study of elective stenting of unprotected LMCA disease to evaluate its immediate and long-term results. Of 61 consecutive patients with unprotected LMCA disease, 6 were excluded. Acute procedural success was 100% for the remaining 55 patients, without any complications such as stent thrombosis, myocardial infarction, CABG, or death. During a mean follow-up of 16.1+/-9.6 months, 11 patients (20%) had symptomatic recurrence, between 2 to 6 months after their procedure. Seven patients underwent CABG, two had repeat intervention, one continued with medical therapy, and one died before planned angiography. There was no late sudden death. Forty-four patients (80%) remained asymptomatic. We conclude that elective stenting may be a safe alternative to CABG in unprotected LMCA disease.

Adenovirus vector-based purging of multiple myeloma cells

Adenoviruses are efficient gene delivery agents for a variety of neoplasms. In the present study, we have investigated the use of adenoviruses for the delivery of the thymidine kinase (tk) gene into multiple myeloma (MM) cells. We first demonstrated that MM cell lines and MM patient cells express both adenovirus receptors as well as the DF3/MUC1 protein, thus providing a rationale for using adenoviruses to selectively deliver genes under the control of the DF3 promoter. By using an adenoviral construct containing beta-galactosidase (beta-gal) gene driven by the DF3 promoter (Ad. DF3-betagal), we demonstrate greater than 80% transduction efficiency in OCI-My5 and RPMI 8226 MM cell lines at a multiplicity of infection of 1 to 100. Importantly, transduction with the tk gene driven by the DF3 promoter (Ad.DF3-tk) followed by treatment with 50 micromol/L ganciclovir (GCV) purged >/=6 log of contaminating OCI-My5 and RPMI 8226 MM cells within bone marrow mononuclear cells. In contrast, normal human hematopoietic progenitor cell number was unaffected under these conditions. Selectivity of DF3/MUC1 promoter was further confirmed, because Ad.DF3-betagal or Ad.DF3-tk did not transduce MUC1-negative HeLa cervical carcinoma cells. In addition, GCV treatment of Ad.DF3-tk-transduced RPMI 8226 MM cells did not induce a significant bystander effect. These findings demonstrate that transduction with Ad vectors using a tumor-selective promoter provides a highly efficient and selective approach for the ex vivo purging of MM cells.

BAD partly reverses paclitaxel resistance in human ovarian cancer cells

Although paclitaxel is an important chemotherapy agent for the treatment of patients with epithelial ovarian cancer, its utility is significantly limited by the frequent development of drug resistance. Recent evidence suggests that resistance to chemotherapy may be partly related to defects in the apoptotic pathway. In this study we have investigated whether enhancement of apoptotic pathway function through stable expression of the BAD protein is capable of sensitizing human epithelial ovarian cancer cells to the effects of chemotherapy. Expression of HA-BAD in six separate clonal transfectants from two different ovarian cancer cell lines was found to significantly enhance the cytotoxic effects of paclitaxel, vincristine, and, to a lesser extent, etoposide. Enhancement of paclitaxel-induced apoptosis in HA-BAD-expressing clones was demonstrated by trypan blue exclusion, clonogenic cell assay, and flow cytometric evaluation. Importantly, this effect was associated with binding of HA-BAD to BCL-xL and concomitant disruption of BAX:BCL-xL interaction. Taken together, these data suggest that the development of small molecules which mimic the effects of BAD may represent a new class of drugs capable of preventing or reversing resistance to chemotherapy agents such as paclitaxel.

BAX protein expression and clinical outcome in epithelial ovarian cancer

PURPOSE

Expression of the pro-apoptotic protein BAX sensitizes ovarian cancer cell lines to paclitaxel in vitro by enhancing the pathway of programmed cell death. The present study was performed to determine the relationship between BAX expression and clinical outcome in 45 patients with newly diagnosed ovarian cancer.

METHODS

BAX protein expression was analyzed by immunohistochemistry, and its relationship with clinical outcome was determined. Assessment of BAX mRNA transcript levels and mutational analysis of the BAX coding region were also performed.

RESULTS

BAX protein was expressed at high levels (defined as > or = 50% of tumor cells positive) in tumor tissue from 60% of newly diagnosed patients. All patients whose tumors expressed high levels of BAX achieved a complete response (CR) to first-line chemotherapy that contained paclitaxel plus a platinum analogue, compared with 57% of patients in the low-BAX group (P = .036). After a median follow-up of 1.9 years, the median disease-free survival (DFS) of patients in the high-BAX group has not been reached, compared with a median DFS of 1.1 years for low-BAX expressors (P = .0061). BAX retained independent prognostic significance in multivariate analysis when corrected for stage and histology. BAX mRNA transcripts were easily detected in samples with low BAX protein expression, and no BAX mutations were identified.

CONCLUSION

The correlation between high BAX levels and improved clinical outcome suggests that an intact apoptotic pathway is an important determinant of chemoresponsiveness in ovarian cancer patients who receive paclitaxel.

Comparison of hemodynamics and recovery of sevoflurane and isoflurane anesthesia in Chinese adult patients

BACKGROUND

The new inhalational anesthetic sevoflurane would be expected to provide a rapid emergence from anesthesia due to its low blood/gas partition coefficient. In this study, we compared the hemodynamic effects, speed and quality of emergence, in ASA class I-II Chinese adult surgical patients receiving either sevoflurane or isoflurane anesthesia.

METHODS

Eighty adult Chinese patients, ASA class I-II, scheduled for elective gynecological or general surgical procedures, were randomized to receive sevoflurane (n = 40) or isoflurane (n = 40) anesthesia. Ventilation is controlled via endotracheal intubation with anesthesia facilitated by either agent at anesthetic concentration of 1-1.5 MAC under the fresh gas flow 2 L/min. Heart rate, arterial blood pressure, temperature, SpO2 and end-tidal CO2 were continuously monitored. Any adverse effect such as airway irritation, nausea or vomiting was recorded during induction and emergence from anesthesia. The emergence time was assessed by various questionales for orientation during recovery. In the post-anesthetic recovery period, pain was monitored and managed by objective pain discomfort scale for analgesic supplements. Complaints of nausea and vomiting were recorded and followed up by a research nurse who visited the patient within 24 h following surgery.

RESULTS

The extent of exposure to anesthetic (MAC x hours) was similar in both groups. Sevoflurane and isoflurane caused similar alterations in systolic and diastolic arterial pressure during maintenance. After surgical incision, the heart rate accelerated more in patients receiving isoflurane (p < 0.05). During emergence, time of response to command was significantly shorter in patients receiving sevoflurane than patients receiving isoflurane (5.6 +/- 0.4 min versus 15.2 +/- 3.0 min, p < 0.001). Side effects such as nausea and vomiting were comparable in both groups.

CONCLUSIONS

Compared with isoflurane, sevoflurane anesthesia had the clinical advantages of maintaining stable hemodynamics and rapid recovery in Chinese adult patients.

Thromboelastographic study of thrombosis in the implantable central venous access device

BACKGROUND

In the present study thromboelastography (TEG) was to study whether or not hypercoagulopathy might contribute to the thrombosis of implantable central venous access device (Port-A-Cath, Pharmacia) in cancer patients.

METHODS

All 76 oncological patients who were enrolled in this study had their R time, alpha angle and MA value measured before Port-A-Cath implantation, of whom 11 patients received re-implantation because of thrombotic device. We compared the measurements of these 11 patients (thrombotic group) with that of 65 patients (control group) who received Port-A-Cath implantation for the first time. According to TEG values the hemostatic status in these patients was classified as hypercoagulable, normal or hypocoagulable for comparison. All patients in the control group were followed up for 3 months for occurrence of thrombosis.

RESULTS

It was found that no patient in the thrombotic group was associated with hypercoagulopathy. Five patients (7.5%) in the control group was found in hypercoagulable status at the time of catheter insertion but none of them developed clinical thrombosis during three months of observation. There was no significant difference between the two groups for R time, alpha angle but a higher MA value was found in the control group (p < 0.05). Furthermore, the hypercoagulability (7.5% for the control vs. none for the thrombotic group), hypocoagulability (1.5% vs. 9.1%) and normocoagulability (91.0% vs. 90.9%) were not statistically different between the two groups (Fisher exact test, P = 0.229).

CONCLUSIONS

We conclude that hypercoagulopathy in cancer patients has little, if any, contribution in thrombosis of the implantable central venous access device.

Comparison of neuromuscular action of rocuronium, a new steroidal non-depolarizing agent, with vecuronium

BACKGROUND

Rocuronium is a new nondepolarizing muscle relaxant. It features a rapid onset and lack of histamine release: It has an intermediate onset of action as vecuronium. The purpose of this study was to compare the neuromuscular action and condition of intubation after a bolus dose of rocuronium or vecuronium (2 x ED90). We also compared the duration of relaxation after intubation and maintenance doses of each drug.

METHODS

Sixty male or female patients, age 18-65, scheduled for elective surgery under general anesthesia were divided randomly into two groups (rocuronium and vecuronium group). All patients were ASA class I-II and pre-operative laboratory data were normal. Anesthesia was performed with fentanyl, isoflurane and O2. Rocuronium 0.6 mg/kg (2 x ED90) or vecuronium 0.1 mg/kg (2 x ED90) was given during induction of anesthesia. The response of adductor pollicis was measured with acceleromyography. Neuromuscular block was maintained by bolus injection of rocuronium 0.15 mg/kg or vecuronium 0.025 mg/kg when T1 reached 25% of control. Onset time, duration, recovery indices, intubation condition and T4/T1 ratio to 70% were recorded. Side effects were recorded during the study.

RESULTS

The onset time was significantly longer in vecuronium group than that of rocuronium group (102.8 +/- 26.9 s vs. 54.9 +/- 10.9 s, p < 0.05). The clinical durations of action were respectively 44.2 +/- 13.2 min in rocuronium group and 42.5 +/- 9.1 min in vecuronium group (T1 to 25%). The duration of the maintenance were respectively 28.8 +/- 9.5 min in rocuronium group and 26.1 +/- 6.8 min in vecuronium group (T1 to 25%). No adverse effect occurred with either drug. The intubation condition was similar in both groups.

CONCLUSIONS

We conclude that rocuronium provides a more rapid onset of action than that of vecuronium. Rocuronium is an intermediate-acting muscle relaxant as vecuronium with good to excellent intubation condition. It may be an useful alternative to vecuronium for rapid tracheal intubation.

Neuropilin is a semaphorin III receptor

The semaphorin family contains a large number of phylogenetically conserved proteins and includes several members that have been shown to function in repulsive axon guidance. Semaphorin III (Sema III) is a secreted protein that in vitro causes neuronal growth cone collapse and chemorepulsion of neurites, and in vivo is required for correct sensory afferent innervation and other aspects of development. The mechanism of Sema III function, however, is unknown. Here, we report that neuropilin, a type I transmembrane protein implicated in aspects of neurodevelopment, is a Sema III receptor. We also describe the identification of neuropilin-2, a related neuropilin family member, and show that neuropilin and neuropilin-2 are expressed in overlapping, yet distinct, populations of neurons in the rat embryonic nervous system.

The genetic penetrance of the activated neu oncogene for the induction of mammary cancer in vivo

Carcinogenesis is most often viewed as a multistage disease process. An exception to this was suggested for neu transformation of mammary cells in a transgenic model (Muller et al., 1988); however, this interpretation is controversial (Bouchard et al., 1989). In order to better define neu mammary transformation in vivo, we directly measured the genetic penetrance of the neu oncogene. Mammary cells in situ were infected with replication-defective retroviral vectors carrying the activated neu oncogene (pJRneu). A limiting dilution in vivo transplantation assay was used to measure the percentage of mammary clonogenic (stem-like) cells that stably and functionally integrated this vector. Based on this, the percentage of clonogens integrating and expressing neu that could progress to mammary carcinomas was quantified to estimate the penetrance of this gene in mammary carcinogenesis. The genetic penetrance of neu was 3.6% (95% confidence interval 2.2%-5.8%). This high degree of genetic penetrance is compatible with the observations that certain neu-transgenic mice develop a very great number of mammary carcinomas (Muller et al., 1988). However, whether these data are compatible with a single-step transformation model (100% penetrance) is uncertain and is discussed.

Early clinical experience with the Multi-Link coronary stent

The Multi-Link coronary stent (Advanced Cardiovascular Systems, Santa Clara, CA) is a balloon expandable stent carved from a stainless steel cylinder and is composed of 12 corrugated rings connected by multiple links. This design gives the stent great flexibility and conformity as well as radial strength. For the 3 month period from November 1995 to January 1996, all patients undergoing stent implantation in our institution were treated with this device, except for vessels smaller than 2.7 mm or larger than 3.7 mm in diameter, left main disease, or those who could not tolerate anticoagulation therapy. Forty patients, with a total of 42 arteries or 44 lesions, were treated with 56 stents, or 1.33 stents per artery. Clinical presentation included stable angina in 13 (32.5%), unstable angina in 24 (60%), acute myocardial infarction in 2 (5%), of whom 1 was in cardiogenic shock, and atypical symptoms with an abnormal thallium stress test in 1 (2.5%). According to the American College of Cardiology/ American Heart Association (ACC/AHA) classification, 8 lesions (18%) were type A, 14 (32%) type B1, 11 (25%) type B2, and 11 (25%) type C. Forty-three lesions (97.7%) were de novo and 1 (2.3%) restenotic. Stent delivery was successful in all patients. Complications included 1 balloon rupture at 7 atm but without sequelae, and 2 patients in whom the coronary guide wire became kinked and locked inside the catheter shaft of the stent delivery system but stent delivery was eventually successful. Mean diameter stenosis was reduced from 76 +/- 13% presenting to 2 +/- 9% poststenting and minimal lumen diameter increased from 0.87 +/- 0.38 to 2.82 +/- 0.34 mm. There were no acute-subacute stent thromboses, bleeding/vascular complications, or major cardiac events such as myocardial infarction, coronary artery bypass surgery, or death during a follow-up period of 2-5 months (mean 3.6 months). In conclusion, our early clinical experience with the Multi-Link stent is very encouraging, with a very high rate of successful delivery and minimal complications.

Case report: lysosomal glycogen storage disease with normal acid maltase: an unusual form of hypertrophic cardiomyopathy with rapidly progressive heart failure

A 14-year-old boy with mild mental retardation, myopathy, and nonobstructive hypertrophic cardiomyopathy (HCM) with clinical and histopathologic features consistent with lysosomal glycogen storage disease with normal acid maltase is described. The case illustrates the aggressive nature of the cardiomyopathy of this syndrome. This condition is associated with malignant ventricular arrhythmias, relentlessly progressive ventricular dilatation, dysfunction, and sudden death. It is important to recognize this unusual and malignant form of HCM to precipitate low early diagnosis by muscle biopsy. Patients with this condition would be excellent candidates for life-saving heart transplant as the myopathy and mental retardation are mild and nonprogressive. The underlying biochemical defect and mode of inheritance of this syndrome are unclear. However, a significant proportion are genetically related and thus, relatives may benefit from family screening.

Site specificity of short-term and long-term habituation in the tail-elicited siphon withdrawal reflex of Aplysia

The study of habituation in animals with relatively simple nervous systems has contributed significantly to the understanding of mechanisms underlying learning and memory. Using the tail-elicited siphon withdrawal reflex of Aplysia, which is mediated in part by bilaterally symmetrical clusters of tail sensory neurons, we found that both short-term and long-term habituation can be restricted laterally, such that habituation produced by stimulation of one side of the tail does not generalize to the other side. Further experiments in this preparation revealed that long-term, laterally restricted habituation is sensitive to the temporal pattern with which stimuli are presented. We also determined that both short-term and long-term habituation can take place in a reduced behavioral preparation, and that short-term habituation can be restricted within relatively small stimulation sites located on the same side of the tail. These results provide insights into the cellular organization of habituation, and they provide a useful preparation for a cellular analysis of this basic form of learning.

Spectrum of electrophysiologic and electropharmacologic characteristics of verapamil-sensitive ventricular tachycardia in patients without structural heart disease

Verapamil-sensitive ventricular tachycardia (VT) is a well-recognized clinical entity that some authorities believe may result from triggered activity. Despite its uniform response to verapamil, however, there is evidence that this uncommon form of VT may not be as homogeneous as first believed. Standard intracardiac electrophysiologic techniques were used to study verapamil-sensitive VT in 32 patients (aged 38 years +/- 20 years) without evidence of structural heart disease. More than half of these patients (69%) exhibited VT with a right bundle branch block-type QRS pattern, with the remainder (31%) displaying VT with a left bundle branch block pattern. In 31% of the patients the VT could be induced by fixed-cycle length atrial pacing, whereas in 59% of patients fixed-cycle length ventricular pacing was necessary. A critical range of cycle lengths for VT induction was required in 66% of the patients. Ventricular tachycardia was initiated with single atrial premature extrastimuli in 16% of patients, single ventricular extrastimuli in 50% of patients, and double ventricular premature extrastimuli in 9% of patients. Ventricular tachycardia displaying cycle-length alternans was observed in 28% of patients. In only 19% of patients was it possible to entrain VT during pacing from the right ventricular apex. Isoproterenol infusion was required for tachycardia induction in 50% of patients, 44% of whom had VT with a left bundle branch block QRS pattern, with the remaining 56% exhibiting VT with a right bundle branch block pattern. Beta-adrenergic blockers suppressed 53% of verapamil-sensitive VT in patients tested, whereas adenosine terminated VT in 50% of patients, with 81% of these patients exhibiting either a left bundle branch block QRS pattern or isoproterenol dependence. Ventricular tachycardia exhibiting a left bundle branch block pattern was more likely to be isoproterenol dependent (p <0.05) and adenosine sensitive (p <0.001). However, verapamil-sensitive, catecholamine-dependent VT was no more likely to be adenosine sensitive than the catecholamine-independent form of the arrhythmia (p >0.5). Verapamil-sensitive VT exhibits properties expected of both a reentrant and triggered arrhythmia, and it is inconsistently dependent on both exogenous catecholamines for induction and intravenous adenosine for termination. Verapamil-sensitive VT encompasses a heterogeneous group of tachycardias that may result from multiple cellular electrophysiologic mechanisms.

Hormonal modulation of neu-induced mammary carcinogenesis: evidence against a single-step induction of mammary cancer by neu

When activated by a point mutation in its transmembrane domain neu is an extremely potent transforming oncogene when expressed in rodent mammary parenchyma. This extreme potency led Muller et al. (13) to suggest the possibility that neu might transform mammary cells by a single step. A corollary to a single-step transformation hypothesis is that transformation efficiency cannot be modulated. Here we test this corollary by introducing mutated neu into in situ rat mammary cells using retroviral vectors and following infection by hormonally modulating recipient rats. Hormonal modulation included raising prolactin levels and lowering glucocorticoid levels. This modulation promotes radiation, chemical and ras initiated mammary carcinogenesis. Here we report that this hormonal promotion protocol also increased the yield of mammary carcinomas following the introduction of the mutated neu gene. We conclude that mutated neu is not a single-step transformer but is a very potent event in the multistage process of mammary carcinogenesis.

Utility of an implantable right ventricular oxygen saturation-sensing pacemaker for ambulatory cardiopulmonary monitoring

Mixed venous oxygen saturation (SvO2) is a physiologic parameter reflecting cardiac output (CO) and tissue oxygen utilization. An implantable oxygen sensor incorporated in a right ventricular pacing lead has been developed to assess the feasibility of ambulatory monitoring of SvO2 to predict cardiorespiratory parameters. Eight patients with a mean age of 62 +/- 2 years and sinoatrial disease received an SvO2-driven dual-chamber rate-adaptive pacemaker capable of continuous SvO2 measurement. During graded maximal exercise with measurement of oxygen consumption (Vo2), arterial oxygen saturation (SaO2), and telemetered derived SvO2 data, CO was assessed using the Fick principle. The accuracy of the derived CO was compared with CO measured directly by continuous-wave Doppler assessment of the ascending aortic flow. The maximum changes in SvO2 and SaO2 during exercise were 25 +/- 5 and 3 +/- 1%, respectively. SvO2 was significantly correlated with Vo2 (r = 0.9 +/- 0.1, p < 0.001), work done (r = 0.8 +/- 0.1, p < 0.05), and minute ventilation (r = 0.9 +/- 0.1, p < 0.05). Doppler-derived CO was significantly correlated with CO estimated from SvO2 measured (r = 0.8 +/- 0.1, p < 0.05) and is expressed as 46x derived CO +300. Although continuous SvO2 sensing was originally developed to increase pacing rate during exercise, its use can be extended for monitoring cardiopulmonary performance on an ambulatory basis. This may be useful as a direct assessment of cardiopulmonary status in diseased states and also as an objective means to evaluate cardiac response to medical therapy in patients with heart failure.

The effects of radiofrequency ablation versus medical therapy on the quality-of-life and exercise capacity in patients with accessory pathway-mediated supraventricular tachycardia: a treatment comparison study

This study aims to evaluate the impact of transcatheter radiofrequency ablation on quality-of-life (QOL) and exercise capacity in patients with paroxysmal supraventricular tachycardia (SVT) on stable medical therapy and the extent of symptomatic benefits of this treatment in patients with SVT of different clinical severity. A total of 55 patients with SVT on stable medications for 3 months were randomly selected for either radiofrequency ablation treatment (46 patients) or continuation of medical therapy (medical control group, 9 patients). Severity of SVT was classified based on the frequency and duration of SVT episodes, hemodynamic disturbance, and the presence of preexcited atrial fibrillation during an episode. Treadmill exercise capacity (Bruce protocol) and QOL (questionnaire study and interview) were assessed before and at 3-month intervals for 1 year after the radiofrequency procedure and at 3 months in the medical control group. Thirty-six of 46 patients were successfully ablated in one session, and a QOL measure before and at 3 months after ablation in these patients showed an improvement in total scores for "General Health Questionnaire" (20.3 +/- 6.2 vs 16.9 +/- 5.3, P < 0.01), "Somatic Symptoms Inventory" (73.0 +/- 6.0 vs 76.1 +/- 4.1, P < 0.02), and "Sickness Impact Profile" (12.6 +/- 1.7 vs 4.9 +/- 3.9, P < 0.01). This improvement in QOL was progressive and sustained over a 1-year period. Major arrhythmia limitations, such as apprehension of strenuous activities and long distance travel, were alleviated after a successful procedure. The extent of improvement in QOL was significant for patients considered to have "mild" or "severe" arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)