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Adenoviral vectors expressing wild-type p53 (Ad-p53) induce apoptosis in different types of cancer cells. The therapeutic utility of Ad-p53 is now being evaluated in prostate-cancer patients. Bcl-2 is frequently expressed by prostate-cancer cells and has previously been shown to inhibit p53-mediated cell death following genotoxic stress. We studied the impact of bcl-2 on Ad-p53-induced cell death in human prostate-cancer cells. Human prostate-cancer cell lines LNCaP (p53 wt) and PC3 (p53 mut) were stably transfected with bcl-2. After p53 transduction, cell viability, apoptosis induction and modulation of specific apoptosis-regulatory proteins were assessed. LNCaP vector control and bcl-2-expressing cells underwent similar decreases in viability associated with apoptosis induction following Ad-p53 infection. Increased bcl-2 expression provided significant protection to PC3 cells transduced with Ad-p53. These findings are correlated with modulations in bax, bcl-2, bcl-x(L) and p21 protein levels. These data suggest that Ad-p53 may be useful in the treatment of some prostate cancers., (Copyright 2001 Wiley-Liss, Inc.)

Background: Secundum atrial septal defect is a common congenital heart defect that causes right heart volume overload and produces symptoms usually after the third decade of life. Treatment until the last few years has been open heart surgery., Objectives: To review our early experience with transcatheter closure of ASD2 using the Amplatzer septal occluder., Methods: Between November 1999 and February 2000, 20 children and young adults with a median age of 9.1 years (4.2-35.1 years) were referred for transcatheter closure of ASD2. Diagnosis was established by transthoracic echocardiography. Implantation was performed under general anesthesia through the femoral vein with the guidance of transesophageal echocardiography and fluoroscopy. Femoral arterial puncture was performed for blood pressure monitoring during the procedure. The device size chosen was similar to the balloon-stretched diameter of the ASD2., Results: Implantation was completed successfully in 18 patients. Two patients were referred for elective surgery: one had an unsuitable anatomy for transcatheter closure by TEE in the catheterization laboratory and the device could not be implanted properly, the other patient had a large multiperforated septal aneurysm that was retrieved. Mean ASD2 diameter by TTE and TEE was similar (13.9 +/- 3 mm, 13.4 +/- 3.5 mm) and mean stretched diameter was 18.3 +/- 4.3 mm. Mean Qp:Qs (pulmonary flow:systemic flow) was 2.2 +/- 0.6. Mean fluoroscopy time for the procedure was 14.8 +/- 4.8 minutes. The patients were discharged the day after the procedure. Four patients had a tiny leak immediately post-procedure, and none had a leak at one month follow-up. The only complication was a small pseudoaneurysm of the femoral artery in one patient, that resolved spontaneously., Conclusions: Transcatheter closure of ASD2 with the Amplatzer septal occluder is a safe and effective alternative to surgical closure. Long-term outcome has to be evaluated.

The impact of bcl-2 proto-oncogene expression on the pathogenesis and progression of prostate cancer was examined in a transgenic mouse model. Probasin-bcl-2 transgenic mice were crossed with TRAMP (TRansgenic Adenocarcinoma Mouse Prostate) mice that express the SV40 early genes (T/t antigens) under probasin control. Prostate size, cell proliferation, apoptosis, and the incidence and latency of tumor formation were evaluated. The double transgenic, probasin-bcl-2 X TRAMP F1 (BxT) mice exhibited an increase in the wet weight of the prostate. This was associated with an increase in proliferation, attributable to T/t antigens, and a decrease in apoptosis attributable to bcl-2. The latency to tumor formation was also decreased in the BxT mice compared to the TRAMP mice. The incidence of metastases was identical in both the TRAMP and BxT mice. Lastly, the incidence of hormone-independent prostate cancer was reduced in the BxT mice compared to the TRAMP mice. Together, these results demonstrate that bcl-2 can facilitate multistep prostate carcinogenesis in vivo.

Recent biochemical and genetic studies have substantially increased our understanding of death signal transduction pathways, making it clear however, that apoptosis is not a single-lane, one-way street. Rather, multiple parallel pathways have been identified. For instance, analysis of bcl-2, bax, p53, and caspase knockout mice while establishing distinct roles for each of these apoptotic players, they also provided valuable information for the design of specific inhibitors of apoptosis. Thus blocking one pathway, as in caspase knockout mice, what we observe is not a complete suppression of apoptosis but rather a delay in apoptosis induction (Hakem et al., 1998; Kuida et al., 1998). In view of nature's means of ensuring activation of a compensatory apoptotic response, when one pathway fails in developing prostate cancer therapeutic interventions, the challenge remains to further dissect individual apoptotic pathways. Advances in our understanding of the integrated functions governing prostate cell proliferation and cell death, clearly suggest that effective prostate cancer therapies are not only molecularly targeted, but that are also customized to take into account the delicate balance of opposing growth influences in the ageing gland. In this review we discuss the evidence on the significance of molecular deregulation of the key players of this growth equilibrium, apoptosis and cell proliferation in prostate cancer progression, and the clinical implications of changes in the apoptotic response in disease detection and therapy.

Development of effective therapeutic modalities for the treatment of human cancer relies heavily upon understanding the molecular alterations that result in initiation and progression of the tumorigenic process. Many of the molecular changes identified in human prostate tumorigenesis so far play key roles in apoptosis regulation. Apoptosis represents a universal and exquisitely efficient cellular suicide pathway. Since the therapeutic goal is to trigger tumor-selective apoptotic cell death (without clinically significant effects on the host), elucidation of the mechanisms underlying apoptosis deregulation will lead to the identification of specific cellular components for targeting therapeutic interventions. As our understanding of its vital role in the development and growth of the prostate gland has expanded, numerous genes that encode apoptotic regulators have been identified that are severely impaired in prostate cancer cells. In addition, the expression of apoptotic modulators within prostatic tumors appears to correlate with tumor sensitivity to traditional therapies such as hormonal ablation and radiotherapy. No strict correlation between apoptosis induction and a patient's long-term prognosis has emerged, perhaps due to the fact that the ability to achieve initial remission alone does not adequately predict long-term outcome. This review will encompass the known molecular changes intimately involved in the apoptotic pathway which have potential prognostic value in disease progression, as well as therapeutic significance in the enhancement of the apoptotic response to novel and established treatment strategies for the treatment of androgen-dependent and androgen-independent prostatic tumors. The main focus will be on the role of the transforming growth factor-beta (TGF-beta) signaling pathway, bcl-2 and the bcl-2 family members, the caspase cascade (apoptosis executioners), and the Fas pathway in induction and regulation of apoptosis following therapeutic stimuli for the management of advanced prostate cancer.

Prostatic glandular epithelial cells undergo apoptosis in response to androgen-deprivation. The molecular determinants of androgen-responsiveness in these cells are incompletely understood. Recent evidence suggests that bcl-2 gene family members may be important in this context. We used the probasin promoter to target a human bcl-2 transgene specifically to the prostate in order to assess its impact on conferring resistance to androgen withdrawal in, otherwise sensitive, prostatic glandular epithelial cells in vivo. We examined the contribution of bax to mediating androgen-responsiveness in prostatic glandular epithelial cells using bax knockout mice. The histologic appearance of the prostates from probasin-bcl-2 transgenic mice or bax-/- mice did not differ from those of control littermates. There was no evidence of hyperplastic or neoplastic growth. There was no difference between probasin bcl-2 transgenic mice, bax-/- mice, and control littermates in steady-state levels of apoptosis. Following castration our findings suggest that both bax and bcl-2 may each contribute to the androgen-responsiveness of prostatic glandular epithelial cells. It is apparent from these results, however, that bax is not required to mediate cell death in prostatic glandular epithelial cells following castration. A comparison between the apoptotic indices in the ventral prostate from the probasin-bcl-2 and bax-/- mice following castration suggests that the presence of bcl-2 may be a more important indicator of androgen-sensitivity than a deficiency of bax.

Objectives: This study was undertaken to evaluate the long-term results of balloon angioplasty (BA) for postsurgical recoarctation in infants., Background: Balloon angioplasty is a well-accepted modality for the treatment of recoarctation. However, infants remain a group of concern because of their size, risk for complications and the potential for restenosis with growth. Age <12 months has been determined to be a risk factor for the development of recoarctation after angioplasty for native coarctation. Although studies on postsurgical coarctation have found no relationship between age at angioplasty and the development of recoarctation, few studies specifically addressing infants have been performed., Methods: Clinical, echocardiographic, hemodynamic and angiographic data on 22 consecutive children <1 year of age who underwent BA between 1986 and 1996 were reviewed., Results: A successful result, defined as a postprocedure gradient of < or =20 mm Hg, was achieved in 20 of 22 (91%) infants with a reduction in the systolic peak pressure gradient from 48 +/- 27 to 9 +/- 10 mm Hg (p < 0.001) and an increase in coarctation diameter from 2.7 +/- 1.1 to 5.2 +/- 1.5 mm (p < 0.001). At long-term follow-up of a median of 56 months (0.6 to 12 years), the restenosis rate after an initial optimal result was 16% (3 of 19). Five (24%) infants required reintervention (2 initially unsuccessful; 3 recoarctation), with a success rate of 95% after two procedures. Suboptimal long-term outcome correlated with a lower infant weight., Conclusions: Balloon angioplasty can be safely performed in infants, with good long-term results. The risk of restenosis is low and can be successfully managed with repeat angioplasty.

Although the phenomenon of programed cell death, or apoptosis, has been recognized for many years, interest in the clinical implications of apoptotic cell death has not been widely apparent until recently. It is now established that the products of at least some oncogenes and tumor suppressor genes are able to regulate the rates of apoptosis as well as proliferation in tumor cell populations. In fact, it appears that evasion of deletion via apoptotic cell death may be a requisite event in the development of many malignant neoplasms. Molecular alterations that occur at high frequency in the pathogenesis of prostate cancer often involve genes implicated in the regulation of cell death. There is now ample reason to speculate that the susceptibility of individual malignant neoplasms to undergo apoptosis in response to a given therapeutic intervention may be a useful parameter in predicting therapeutic response. This realization has profound implications with respect to the design and implementation of treatment strategies for prostate cancer based on the biology of this disease.

Successful stent implantation for conduit stenosis has been described; however, this procedure may be complicated by compression of adjacent structures during expansion. We report on a rare case of a single right coronary artery system complicating stent implantation for relief of homograft stenosis in tetralogy of Fallot.

A role has been delineated for both bcl-2 and NF-kappa B in mediating an adaptive survival response to the TNF-alpha signaling pathway for apoptosis. Additionally, we and others have demonstrated a role for bcl-2 upregulation during progression of prostate cancer and acquisition of androgen-independent growth (T. J. McDonnell et al., 1992, Cancer Res. 52, 6940-6944). Therefore, the relationship between bcl-2 and NF-kappa B in regulating TNF-alpha-induced apoptosis was investigated in prostate carcinoma cells. Enforced overexpression of bcl-2 protein in prostatic carcinoma cells impaired TNF-alpha-mediated cytotoxicity. Expression of bcl-2 did not impose a block to, or potentiate, TNF-alpha signaling of I kappa B alpha degradation, nuclear import of the RelA p65, or NF-kappa B-dependent transactivation. Expression of two dominant-negative I kappa B alpha mutant proteins significantly enhanced TNF-alpha-induced apoptosis in control cells but not in cells expressing high levels of bcl-2 protein. Similarly, PDTC, a strong antioxidant that interferes with activation of NF-kappa B in these prostate carcinoma cells, also potentiated TNF-alpha-stimulated apoptosis signaling through a bcl-2-regulated mechanism. These findings indicate that modulation of NF-kappa B survival signaling may be used to clinical advantage in the treatment of prostate cancer patients. The efficacy of strategies proposed to enhance TNF-alpha-mediated cytotoxicity by inhibiting NF-kappa B will likely be influenced by context-dependent variables such as bcl-2 expression.

We report the immediate results and the short-term follow-up in a group of selected patients with coarctation of the aorta who underwent endovascular stent implantation. Balloon-expandable stents were implanted in 6 patients (mean age 19.8 +/- 5.1 years) with coarctation of the aorta (4 recurrent and 2 native) who underwent a total of 7 procedures (6 implantation and 1 further expansion). The systolic peak pressure gradient was decreased from 36.7 +/- 16.9 to 13.3 +/- 23.2 mm Hg (P < 0.005). There was a 66% increase in the mean coarctation diameter from 9.3 +/- 1.7 to 15.6 +/- 3.1 mm (P = 0.001) with the ratio of the coarctation to descending aorta diameter, measured at the level of the diaphragm, increasing from 0.49 +/- 0.1 to 0.81 +/- 0.2 (P < 0.005). The dilatation was successful in expanding the stent to an acceptable diameter in 5 of 6 patients. One patient underwent successful further expansion of a stent implanted 22 months previously. There were no immediate complications during balloon expansion and stent implantation. One patient suffered a femoral arterial bleed requiring surgical repair. There was one unrelated death. All patients were hypertensive (systolic blood pressure > 140 mm Hg) prior to stent implantation. At mean follow-up of 8 months, 3 patients are normotensive. There was no recurrence of coarctation, aortic dissection, or aneurysm formation in the patients in whom stent implantation was successful. These findings indicate that balloon-expandable stent implantation for coarctation of the aorta in selected patients is a safe and effective alternative approach for relieving the obstruction with a low complication rate and no recoarctation at short-term follow-up.

Membrane phospholipid asymmetry is an important regulator of cellular function and homeostasis. The activities of lipid transporters are contributing factors to the regulation of membrane lipid composition over the lifespan of the cell. Alterations in the activities of these proteins result in the movement of phosphatidylserine to the cell's outer leaflet. This promotes several physiologic responses including initiation of the coagulation cascade and cell recognition by the reticuloendothelial system.

Cytoskeleton-free vesicles released from human red blood cells (RBC) transport exogenously supplied aminophospholipid analogues from the vesicle's outer to inner leaflet at rates comparable to those of normal RBC (Beleznay et al. (1993) Biochemistry 32, 3146-3152). Because polypeptides associated with the Rh blood group system have been implicated in the transbilayer movement of phosphatidylserine (PS), we investigated the relationship and co-localization of the aminophospholipid translocase and Rh in dilauroylphosphatidylcholine-induced RBC vesicles. The transbilayer movement of fluorescent (NBD-PS) and photoactivatable (125I-N3-PS) PS in RBC vesicles was ATP-and temperature-dependent. Inhibition of PS transport by sulfhydryl reagents could be accomplished by direct vesicle treatment or by treating RBC before vesiculation. In the case of diamide- and pyridyldithioethylamine-mediated inhibition, NBD-PS transport could be restored by reduction with dithiothreitol, indicating that the movement of the PS transporter into the emerging vesicle was independent of the oxidative status of membrane sulfhydryls. The presence of Rh polypeptides in the vesicles was verified by direct immunoprecipitation of isotopically-labeled Rh and semi-quantified by antibody adsorption assays. Similar to the movement of the PS transporter, localization of Rh polypeptides in the vesicle membrane was independent of the red cell's oxidative status. These results show that the PS translocase and Rh-related proteins colocalize in RBC vesicles suggesting that these proteins may be members of a multicomponent complex that plays a role in lipid movement and the generation of membrane lipid asymmetry.