Cathepsin D primes caspase-8 activation by multiple intra-chain proteolysis

During the resolution of inflammatory responses, neutrophils rapidly undergo apoptosis. A direct and fast activation of caspase-8 by cathepsin D was shown to be crucial in the initial steps of neutrophil apoptosis. Nevertheless, the activation mechanism of caspase-8 remains unclear. Here, by using site-specific mutants of caspase-8, we show that both cathepsin D-mediated proteolysis and homodimerization of caspase-8 are necessary to generate an active caspase-8. At acidic pH, cathepsin D specifically cleaved caspase-8 but not the initiator caspase-9 or -10 and significantly increased caspase-8 activity in dimerizing conditions. These events were completely abolished by pepstatin A, a pharmacological inhibitor of cathepsin D. The cathepsin D intra-chain proteolysis greatly stabilized the active site of caspase-8. Moreover, the main caspase-8 fragment generated by cathepsin D cleavage could be affinity-labeled with the active site probe biotin-VAD-fluoromethyl ketone, suggesting that this fragment is enzymatically active. Importantly, in an in vitro cell-free assay, the addition of recombinant human caspase-8 protein, pre-cleaved by cathepsin D, was followed by caspase-3 activation. Our data therefore indicate that cathepsin D is able to initiate the caspase cascade by direct activation of caspase-8. As cathepsin D is ubiquitously expressed, this may represent a general mechanism to induce apoptosis in a variety of immune and nonimmune cells.

Deficiency in SLC25A1, encoding the mitochondrial citrate carrier, causes combined D-2- and L-2-hydroxyglutaric aciduria

The Krebs cycle is of fundamental importance for the generation of the energetic and molecular needs of both prokaryotic and eukaryotic cells. Both enantiomers of metabolite 2-hydroxyglutarate are directly linked to this pivotal biochemical pathway and are found elevated not only in several cancers, but also in different variants of the neurometabolic disease 2-hydroxyglutaric aciduria. Recently we showed that cancer-associated IDH2 germline mutations cause one variant of 2-hydroxyglutaric aciduria. Complementary to these findings, we now report recessive mutations in SLC25A1, the mitochondrial citrate carrier, in 12 out of 12 individuals with combined D-2- and L-2-hydroxyglutaric aciduria. Impaired mitochondrial citrate efflux, demonstrated by stable isotope labeling experiments and the absence of SLC25A1 in fibroblasts harboring certain mutations, suggest that SLC25A1 deficiency is pathogenic. Our results identify defects in SLC25A1 as a cause of combined D-2- and L-2-hydroxyglutaric aciduria.

The feasibility, efficacy and functional outcome of local anaesthetic repair of anterior and posterior vaginal wall prolapse

INTRODUCTION: Urogenital prolapse is a very common condition in women with a prevalence of 30%. If conservative therapy fails or is not desired by the patient, prolapse repair is usually performed under general or regional anaesthetic. The aim of the study was to evaluate feasibility, efficacy and functional outcome after fascial prolapse repairs under local anaesthetic (LA). PATIENTS AND METHODS: Between November 1999 and December 2000, 130 consecutive patients presenting with anterior or posterior prolapse or both were invited to have their procedure performed under LA. All patients with a symptomatic minimum stage II prolapse were included. Prior to surgery all women completed a standardized questionnaire examining the specific and non-specific symptoms of prolapse and their situation was classified using the ICS Pelvic Organ Prolapse (POP-Q) system. Follow up was 30 months. Objective success was defined as a stage 1 or less and no symptoms of bulge, subjective success was defined as lack of specific or non-specific symptoms of prolapse. RESULTS: There were 128 patients who agreed to have their operations performed under LA: 68 in the anterior group, 52 in the posterior group and 8 with a combined anterior and posterior repair. Objective cure rate was 88% for posterior repair, 87% for anterior repair and 63% for combined repair. Success rates were no different in primary from recurrent cases. There were no intraoperative complications and operating time was 21 min (anterior repair) or 23 min (posterior repair). There was no de novo postoperative urinary or stool incontinence and all patients but two would have the operation performed again under the same circumstances. The two remaining refused due to embarrassment but for no other reason. CONCLUSION: Local anaesthetic prolapse repair is feasible and effective in middle term results. It is well accepted by the patients who benefit from less side effects and short hospital stay.

Steam pops during irrigated radiofrequency ablation: feasibility of impedance monitoring for prevention

BACKGROUND: Steam pops are a risk of irrigated radiofrequency catheter ablation (RFA) and may cause cardiac perforation. Data to guide radiofrequency (RF) energy titration to avoid steam pops are limited. OBJECTIVE: This study sought to assess the frequency and consequence of audible pops and to determine the feasibility of using the magnitude of impedance change to predict pops. METHODS: We reviewed consecutive endocardial open-irrigated RFA for ventricular tachycardia (VT) with continuously recorded ablation data in 142 patients with structural heart disease. Steam pops were defined as an audible pop associated with a sudden spike in impedance. Ablation lesions before or after pops served as controls. RESULTS: From a total of 4,107 ablation lesions, 62 (1.5%) steam pops occurred in 42 procedures in 38 patients. Perforation with tamponade occurred with 1 of 62 (2%) pops. Applications with pops had a greater impedance decrease (22 +/- 7 Omega vs. 18 +/- 8 Omega, P = .001) and a higher maximum power (45 +/- 5 W vs. 43 +/- 6 W, P = .011), but did not differ in maximum catheter tip temperature (40 degrees C +/- 4 degrees C vs. 40 degrees C +/- 4 degrees C, P = .180) from applications without pops. Eighty percent of pops occurred after impedance decreased by at least 18 Omega. CONCLUSION: During VT ablation with open irrigation, audible pops are infrequent and do not usually cause perforation. Limiting RF power to achieve an impedance decrease of <18 Omega is a feasible method of reducing the likelihood of a pop when perforation risk is of concern.

Sexual function after sacrospinous fixation for vaginal vault prolapse: bad or mad?

BACKGROUND: The main indication for sacrospinous ligament suspension is to correct either total procidentia, a posthysterectomy vaginal vault prolapse with an associated weak cardinal uterosacral ligament complex, or a posthysterectomy enterocele. This study aimed to evaluate sexual function and anatomic outcome for patients after sacrospinous ligament suspension. METHODS: For this study, 52 patients who had undergone sacrospinous ligament fixation during the preceding 5 years were asked to complete the Female Sexual Function Index (FSFI) questionnaire. The patients were vaginally examined using the ICS POP score, and the results were compared with their preoperative status. For statistical analysis, GraphPad for Windows, version 4.0, was used. RESULTS: The 52 patients were examined during a follow-up period of 38 months. No major intraoperative complications were noted. Recurrence of symptomatic apical descent was noted in 6% of the patients and de novo prolapse in 13.5%. Only one patient was symptomatic. Three patients experienced de novo dyspareunia, which resolved in two cases after stitch removal. Sexual function was good, rating higher than three points for each of the domains including satisfaction, lubrication, desire, orgasm, and pain. CONCLUSION: Sacrospinous ligament fixation still is a valuable option for the treatment of vaginal vault prolapse. Sexual function is satisfactory, with few cases of de novo dyspareunia.

Sexual function after suburethral sling removal for dyspareunia

INTRODUCTION: Impact on sexual function has received little attention in the medical literature for a long time. Because of the site of insertion of permanent tension free vaginal tape (TVT) the G spot might be affected or the tape might interfere with arousal and sensory stimulation. Recent studies have reported varying degrees of sexual impairment after TVT insertion ranging from 0% to 15% including dyspareunia. AIM: The aim of this study was to evaluate sexual function before and after suburethral sling removal due to postoperative female de novo dyspareunia. As a secondary outcome, general patients' satisfaction with their overall continence situation was assessed. PATIENTS AND METHODS: Between December 2005 and December 2007, we included 18 female patients who complained of de novo dyspareunia after suburethral sling insertion for urinary stress incontinence. All patients filled in an FSFI questionnaire prior to sling removal and at 3 months postoperatively. Additionally, all women were asked to estimate their general satisfaction regarding their continence situation using a Visual Analogue Scale (VAS) from 0 to 10, with 0 being the least satisfying situation and 10 being the most satisfying situation. All patients underwent gynaecological examination including ICS-pelvic organ prolapse staging (ICS-POP score). RESULTS: Of the 18 slings, ten were transobturator tapes (6 x TVT-O, 2 x Monarch, 2 x unknown) and eight were retropubic tapes (7 x TVT, 1 x SPARC). Desire, arousal, lubrication, satisfaction, and pain improved statistically significant. Orgasm scores were low with median scoring of 1.5 scores before and 1.0 scores after sling removal, and they did not change significantly after sling removal. The satisfaction rate deteriorated from a median of 7 (95% confidence interval [CI] 6.3-7.7) to a median of 4 (95% CI 3.7-5.1; p=0.99) but not statistically significant. CONCLUSIONS: Sexual function in patients with de novo dyspareunia is likely to improve after sling removal but not in all domains. Bladder function may deteriorate.