RNA expression bcl-w, a new related protein Bcl-2 family, and caspase-3 in isolated sertoli cells from pre-pubertal rat testes

Apoptosis has a major role in molding the embryo, in the maintenance of tissue homeostasis, and in the defense against pathogens, while its disgregulation is strongly implicated in cancer as well as in autoimmune and degenerative diseases. The opposite action of anti-apoptotic proteins (Bcl-2 family) and pro-apoptotic proteins (p53, Bax, Bak) regulates the activation of caspases that are the effectors proteases of the cell suicide. Bcl-W is a pro-survival protein, recently discovered, related to the Bcl-2 family. The presence of Bcl-W is fundamental for spermatogenesis in rats. Caspases are cysteine-dependent aspartate-specific proteases, and their over-expression can result in apoptotic cell death. Normally, caspases exist in cells as inactive pro-enzymes and can be activated by 2 distinct mechanisms: the FADD/caspase 8 cascade, and the Apaf-1/caspase 9 cascade. These 2 mechanisms are used extensively by cells for the activation of the effectors caspases: caspase 3, caspase 6, and/or caspase 7. Bcl-W and caspases might have a pivotal role in maintenance of Sertoli cells integrity. In this study, we demonstrate that both Bcl-W mRNA and caspase 3 mRNA are expressed in isolated Sertoli cells of pre-puberal rat testes. This finding might be crucial in clarifying whether Sertoli cells die by an apoptotic mechanism. Further studies are required to understand whether the expression of Bcl-W and caspases is different before and after puberty in rat testis and/or in pathological conditions, that lead to an increased cell apoptosis.

Effects of balloon injury on neointimal hyperplasia in streptozotocin-induced diabetes and in hyperinsulinemic nondiabetic pancreatic islet-transplanted rats

BACKGROUND

The mechanisms of increased neointimal hyperplasia after coronary interventions in diabetic patients are still unknown.

METHODS AND RESULTS

Glucose and insulin effects on in vitro vascular smooth muscle cell (VSMC) proliferation and migration were assessed. The effect of balloon injury on neointimal hyperplasia was studied in streptozotocin-induced diabetic rats with or without adjunct insulin therapy. To study the effect of balloon injury in nondiabetic rats with hyperinsulinemia, pancreatic islets were transplanted under the kidney capsule in normal rats. Glucose did not increase VSMC proliferation and migration in vitro. In contrast, insulin induced a significant increase in VSMC proliferation and migration in cell cultures. Furthermore, in VSMC culture, insulin increased MAPK activation. A reduction in neointimal hyperplasia was consistently documented after vascular injury in hyperglycemic streptozotocin-induced diabetic rats. Insulin therapy significantly increased neointimal hyperplasia in these rats. This effect of hyperinsulinemia was totally abolished by transfection on the arterial wall of the N17H-ras-negative mutant gene. Finally, after experimental balloon angioplasty in hyperinsulinemic nondiabetic islet-transplanted rats, a significant increase in neointimal hyperplasia was observed.

CONCLUSIONS

In rats with streptozotocin-induced diabetes, balloon injury was not associated with an increase in neointimal formation. Exogenous insulin administration in diabetic rats and islet transplantation in nondiabetic rats increased both blood insulin levels and neointimal hyperplasia after balloon injury. Hyperinsulinemia through activation of the ras/MAPK pathway, rather than hyperglycemia per se, seems to be of crucial importance in determining the exaggerated neointimal hyperplasia after balloon angioplasty in diabetic animals.

Membrane-bound protein kinase A inhibits smooth muscle cell proliferation in vitro and in vivo by amplifying cAMP-protein kinase A signals

cAMP-dependent protein kinase is anchored to discrete cellular compartments by a family of proteins, the A-kinase anchor proteins (AKAPs). We have investigated in vivo and in vitro the biological effects of the expression of a prototypic member of the family, AKAP75, on smooth muscle cells. In vitro expression of AKAP75 in smooth muscle cells stimulated cAMP-induced transcription, increased the levels of the cyclin-dependent kinase-2 inhibitor p27(kip1), and reduced cell proliferation. In vivo expression of exogenous AKAP75 in common carotid arteries, subjected to balloon injury, significantly increased the levels of p27(kip1) and inhibited neointimal hyperplasia. Both the effects in smooth muscle cells in vitro and in carotid arteries in vivo were specifically dependent on the amplification of cAMP-dependent protein kinase (PKA) signals by membrane-bound PKA, as indicated by selective loss of the AKAP75 biological effects in mutants defective in the PKA anchor domain or by suppression of AKAP effects by the PKA-specific protein kinase inhibitor. These data indicate that AKAP proteins selectively amplify cAMP-PKA signaling in vitro and in vivo and suggest a possible target for the inhibition of the neointimal hyperplasia after vascular injury.

A new rat model of small vessel stenting

OBJECTIVES

Restenosis is the major complication of coronary angioplasty and stenting. In addition, the small vessel diameter represents a major limitation to the wide use of the technology. The aim of this study was to assess the feasibility and the vascular response of stent deployment in rat small vessels.

METHODS

In 40 Wistar rats (500-550 g) a Nir stent crimped on a 1.5 mm Comet angioplasty balloon catheter was deployed at high pressure in the common carotid artery. Neointimal area, neointima/media ratio and the arterial dimension were assessed immediately and at 7, 14, 21, and 28 days after stenting.

RESULTS

After stent deployment, the neointimal area and the neointima/media ratio increased progressively and peaked at 14 days (p < 0.05 vs 0 and 7 days). Alpha-actin-positive cells were found circumferentially organized on the lumen surface. At 21 and 28 days after stenting, the neointima and the neointima/media ratio were not statistically different compared with the results obtained fourteen days after stent deployment. No significant differences in the area of external elastic lamina were observed during the study period. In contrast, the internal lumen area was reduced significantly at 14, 21, and 28 days after the stent deployment. Subacute thrombosis rate after stent implantation was 26.5 %.

CONCLUSIONS

The results of this study demonstrated that the balloon expandable stents can be safely placed into rat arteries and the reduction of the internal arterial lumen observed after stent deployment was only due to the neointima formation whereas remodeling did not occur.

Gene therapy for restenosis after balloon angioplasty and stenting

Percutaneous coronary revascularization is an increasingly attractive alternative to medical therapy and surgical revascularization for coronary artery disease. The leading drawback of this procedure continues to be restenosis-the process of late arterial renarrowing at the site of initially successful intervention. Restenosis after balloon angioplasty seems to be determined primarily by the direction and magnitude of vessel wall remodeling. In contrast, the major limitation of stent implantation is the initiation of neointimal tissue proliferation within and adjacent to the stent. The goal of this review is to summarize recent laboratory and clinical investigations of the transmission of mitogenic signals from the membrane to the nucleus in smooth muscle cells. The mechanisms responsible for restenosis after balloon angioplasty and stenting and the possibility of transferring specific genes into somatic vascular cells with molecular tools to inhibit smooth muscle cell proliferation also will be reviewed.

Limb shortening for the management of leg length discrepancy

Limb shortening is an option to manage leg length discrepancy (LLD). Before skeletal maturity, a LLD between 2 and 5 cm can be corrected by epiphyseodesis (open or closed) or stapling. All these procedures require exact timing of surgery. In skeletally mature patients, shortening of the femur is considered safer than tibial shortening. Subtrochanteric and supracondylar osteotomies fixed with a blade-plate can be used to correct associated deformity. Mid-shaft shortening can be performed by a closed or open method. Closed shortening has been widely used, but frequent malrotation, loss of function and acute respiratory distress syndrome following reaming have been reported. Therefore, the use of a nail locked proximally and distally, and caution in reaming the canal, are strongly recommended. For LLDs greater than 10 cm, lengthening should be considered, although a one-stage two-limb procedure can be used, whereby shortening is performed on the longer limb, and the excised bone segment is implanted in the contralateral limb to be lengthened. However, when shortening procedures are performed in skeletally immature patients, they require precise timing, and indications and technical details must be strictly observed.

Secretion of cytokines upon allogeneic stimulation: effect of aging

The aim of the present study was to investigate the in vitro mitotic response and cytokine production after allogeneic stimulation of peripheral blood mononuclear cells (PBMC) from healthy elderly subjects. Interleukin-1 (IL-1), interleukin-2 (IL-2), gamma-Interferon (gamma-IFN), and Tumor Necrosis Factor alpha (TNF-alpha) were detected in the supernatants of mixed lymphocyte cultures (MLC). The in vitro proliferative response was significantly reduced in the elderly subjects. The amount of IL-2 detected in the supernatant from cultures of cells from elderly donors was higher than for young controls, as were the production of cytokines predominantly secreted by the macrophage population (IL-1 and TNF-alpha). There was no difference in the production of gamma-IFN by cells of elderly and young subjects.

An acyl-coenzyme A chain length dependent assay for 3-oxoacyl-coenzyme A thiolases employing acetyldithio-coenzyme A

An assay for 3-oxoacyl-coenzyme A (3-oxoacyl-CoA) thiolases is described. The reaction utilizes acetyldithio-CoA as the nucleophile and variable chain length saturated acyl-CoA's as the electrophiles. The properties of the 3-oxoacyl-CoA dithioester product, notably a pKa of 6.6 +/- 0.1 and an extinction coefficient of 21,600 cm-1 M-1 for the enethiolate at 357 nm, make it possible to spectrophotometrically follow the reaction in the thermodynamically unfavorable carbon-carbon bond-forming direction. These properties eliminate both the background decomposition and the dependence on Mg2+, chain length, and pH that complicate assays with 3-oxoacyl-CoA substrates. Purified thiolase I from pig liver was 140-fold more active with butyryl-CoA as the electrophile than with acetyl-CoA and 38-fold more reactive with hexanoyl-CoA than with myristoyl-CoA. Beef liver homogenate showed a much greater relative activity with myristoyl-CoA as the electrophile than either purified pig heart thiolase I or pig heart homogenate. The analysis of the separation of thiolases by anion-exchange chromatography is simplified and further suggests the existence of isozymes with varying chain length specificities.

[Correlation of positivity for serum anti-chlamydia antibodies and tubal damage as a cause of infertility. Preliminary study]

Chlamydia Trachomatis is one of the most frequently bound aetiological agents in acute salpingitis. Chlamydia infection often runs asymptomatically or with slight symptomatology, so patients do not call in their doctor. This hypothesis is backed by the observation that serum antibody positivity for Chlamydia and tubal infertility are often found together. The purpose of the present study was to determine the positivity of serum antibodies for Chlamydia in infertile women observed at this Centre and compare it with a control group of non-sterile patients. Further, in those patients in whom antibody positivity exists, it was also proposed to seek tubal lesions at hysterosalpingography or coelioscopy. The antibody titre in infertile women is compared with that of the control group. The study was carried out in 30 sterile women and in 30 patients in the definitely fertile control group. The "Ipazyme" (Sorin) immunoperoxidase test was used to seek IgG and IgA anti-Chlamydia antibodies. The geometric mean of the antibody titre was calculated in those women with a titre equal to or greater than 64 for IgG antibodies and equal to or greater than 16 for IgA antibodies. It is now intended to study whether the titre is higher in infertile women compared to the control group and if positivity is more significant in these patients.

Effects of cyclosporin A on in vitro lymphocyte response to autologous or allogeneic stimulation: influence of HLA phenotypes

In this study we investigated whether the interindividual variability of lymphocyte sensitivity to cyclosporin A (CsA) could be controlled by the HLA region. The models used were the in vitro primary and secondary autologous (AMLR) and allogeneic mixed lymphocyte (MLR) cultures of cells from 32 healthy subjects from our HLA reference panel. Our results show that CsA inhibited primary allogeneic MLR to a much greater extent than primary AMLR (-81 +/- 2% vs -38 +/- 8%, P less than 0.001). The same pattern was observed when cells harvested from CsA-treated primary cultures were rechallenged in secondary cultures with the original sensitizing stimulator cells (-40 +/- 6% vs -17 +/- 9%, P less than 0.05). No differences were observed in primary autologous and allogeneic cultures among responders of different HLA phenotypes. In contrast, the secondary responses did vary according to the HLA types: in secondary AMLR, CsA-priming did not lower, or even enhance, the proliferative responses of DR5+ and/or DR2+ lymphocytes (+7 +/- 13%), whereas it significantly lowered the responses of DR2-5- cells (-46 +/- 8%). In secondary MLR, lymphocytes proliferation was lowered by CsA-priming in all but DRW11(5)+ subjects (-45 +/- 7% vs +2 +/- 23%, P less than 0.05). It is concluded that the individual HLA phenotype influences the pattern of lymphocyte sensitivity to CsA.

[Determination of anti-core antibodies with the immunoenzymatic method. Comparison with the radioimmunological method]

The authors tested 366 samples for the detection of HBcAb using enzyme-linked immunosorbent assay (ELISA) and radioimmuno assay (RIA). Twenty samples were titered to compare the sensitivity of the two tests. The results showed that the two methods gave very similar results, with only a few doubtful cases for RIA. ELISA seems to be more sensitive than RIA for the titration of the positive samples. The authors conclude that the ELISA method is easier than RIA and does not require any apparatus in particular.