The impact of haptic learning in telemanipulator-assisted surgery

BACKGROUND: The use of a telemanipulator requires special training and surgical performance is associated with a learning curve. The aim of this study was to demonstrate the potential value of Haptic-Visual over Visual-Only passive Training in telemanipulator-assisted surgery. METHODS: Two telemanipulator consoles (da Vinci, Intuitive Surgical) were linked through an Application Programer's Interface allowing the applicant at the training console to register the position and passively follow the motions of the instructor's master telemanipulators (MTMs) at the master console (Haptic-Visual Learning group, HVL). The applicant could not actively interfere with the MTM movements. Both the trainee and the instructor shared the same 3-dimensional vision. Alternatively, subjects received only standard visual training without touching the MTMs (Visual-Only Learning group, VL). A standardized demonstration of tasks and the system was given for both groups. Participants (n=20) without previous experience with telemanipulation performed a set of various tasks in a randomized order. Study end points were time and accuracy required to perform the different task. RESULTS: The first task, with moving items to appropriate locations, showed differences in time to perform the task [mean: 4:06 min (HVL) vs. 5:16 min (VL) (P=0.2)] and accuracy differed among groups [mean number of errors 1.7 (VL) vs. 1.3 (HVL) P=0.38]. With more challenging tasks [cut out round figures (cut) and performing double dot suture lines (sti)] the number of errors was less in the HVL group [mean: 1.1 errors (cut) (P=0.05) and 1.8 errors (sti) (P=0.26)] compared with the VL group [mean: 1.8 errors (cut) and 2.3 errors (sti)]. In addition, the time to perform the tasks decreased in the HVL group with mean: 5.42 minutes (cut) (P=0.26) and 9.41 minutes (sti) (P=0.36) compared with the VL group with mean: 7.09 minutes (cut) and 11.43 minutes (sti). CONCLUSIONS: This study demonstrated the impact of haptic-visual passive learning in telemanipulator-assisted surgery which may alter the training for telemanipulator-assisted endoscopic procedures.     

Diagnostic criteria, classification, and nomenclature for painful bladder syndrome/interstitial cystitis: an ESSIC proposal

OBJECTIVES: Because the term "interstitial cystitis" (IC) has different meanings in different centers and different parts of the world, the European Society for the Study of Interstitial Cystitis (ESSIC) has worked to create a consensus on definitions, diagnosis, and classification in an attempt to overcome the lack of international agreement on various aspects of IC. METHODS: ESSIC has discussed definitions, diagnostic criteria, and disease classification in four meetings and extended e-mail correspondence. RESULTS: It was agreed to name the disease bladder pain syndrome (BPS). BPS would be diagnosed on the basis of chronic pelvic pain, pressure, or discomfort perceived to be related to the urinary bladder accompanied by at least one other urinary symptom such as persistent urge to void or urinary frequency. Confusable diseases as the cause of the symptoms must be excluded. Classification of BPS types might be performed according to findings at cystoscopy with hydrodistention and morphologic findings in bladder biopsies. The presence of other organ symptoms as well as cognitive, behavioral, emotional, and sexual symptoms, should be addressed. CONCLUSIONS: The name IC has become misleading and is replaced by BPS. This name is in line with recent nomenclature recommendations by the European Association of Urology and is based on the axial structure of the International Association for the Study of Pain classification. To facilitate the change of the name, ESSIC agreed to include IC in the overall term (BPS/IC) during this transition period.     

Poly(ADP-ribose) polymerase inhibition improves endothelial dysfunction induced by reactive oxidant hydrogen peroxide in vitro

Reactive oxygen species, such as hydrogen peroxide (H(2)O(2)) induce oxidative stress and DNA-injury. The subsequent activation of poly(ADP-ribose) polymerase (PARP) has been implicated in the pathogenesis of various cardiovascular diseases including ischaemia-reperfusion injury, circulatory shock, diabetic complications and atherosclerosis. We investigated the effect of PARP-inhibition on endothelial dysfunction induced by H(2)O(2). In vascular reactivity measurements on isolated rat aortic rings we investigated the phenylephrine-induced contraction, and endothelium-dependent and -independent vasorelaxation by using cumulative concentrations of acetylcholine and sodium nitroprusside. Endothelial dysfunction was induced by exposing the rings to H(2)O(2) (200 and 400 muM) for 30 min. In the treatment group, rings were preincubated with the potent PARP-inhibitor INO-1001. DNA strand breaks were assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method. Immunohistochemical analysis was performed for poly(ADP-ribose) (the enzymatic product of PARP) and for apoptosis inducing factor (a pro-apoptotic factor regulated by PARP). Exposure to H(2)O(2) resulted in reduced contraction forces and a dose-dependent impairment of endothelium-dependent vasorelaxation of aortic rings (maximal relaxation to acetylcholine: 86.21+/-1.574% control vs. 72.55+/-1.984% H(2)O(2) 200 muM vs. 66.86+/-1.961% H(2)O(2) 400 muM; P<0.05). PARP-inhibition significantly improved the acetylcholine-induced vasorelaxation (77.75+/-3.019% vs. 66.86+/-1.961%; P<0.05), while the contractility remained unaffected. The dose-response curves of endothelium-independent vasorelaxation to sodium nitroprusside did not differ in any groups studied. In the H(2)O(2) groups immunohistochemical analysis showed enhanced PARP-activation and nuclear translocation of apoptosis inducing factor, which were prevented by INO-1001. Our results demonstrate that PARP activation contributes to the pathogenesis of H(2)O(2)-induced endothelial dysfunction, which can be prevented by PARP inhibitors.     

Effects of 7-ketocholesterol on the activity of endothelial poly(ADP-ribose) polymerase and on endothelium-dependent relaxant function

Oxidative and nitrosative stress play an important role in the development of endothelial vascular dysfunction during early atherosclerosis. Oxidative stress activates the nuclear enzyme poly(ADP-ribose) polymerase (PARP) in endothelial cells. In patients with atherosclerosis the level of oxidized LDL in the plasma is elevated. In oxidized LDL various oxysterols have been identified, such as 7-ketocholesterol (7K). 7K has been shown to induce PARP activation in microglial cells. The aim of the current study was to clarify the effects of 7K on the activity of endothelial PARP and on the endothelium-dependent relaxant function of blood vessels. We treated human umbilical vein endothelial (HUVEC) cells with 2-16 microg/ml 7K as well as vascular rings harvested from BALB/c mouse thoracic aorta with 90 microg/ml 7K for 2 h. A group of mice was treated with 7K subcutaneously for 1 week (10 mg/kg/day). We also conducted in vitro and in vivo experiments using pretreatment with buthionine sulphoximine (BSO), a glutathione-lowering agent. The activity of PARP was calculated by measurement of tritiated NAD incorporation. The activity of PARP increased significantly in 7K-treated HUVEC cells. After BSO pretreatment, this increase was higher. Isolated vascular rings demonstrated no change in endothelium-dependent relaxant function after 2 h of incubation with 7K, even after BSO pretreatment. In vivo treatment with 7K for 1 week had no effect on the relaxant function. Our experimental results suggest that although 7-ketocholesterol can activate PARP enzyme in endothelial cells, it is not sufficient on its own to cause impairment in the endothelium-dependent vascular reactivity.     

The Arg16Gly-β2-adrenoceptor single nucleotide polymorphism: exercise capacity and survival in patients with end-stage heart failure

Heart failure (HF) is characterized by impaired myocardial β-adrenergic signal transduction. Single nucleotide polymorphisms (SNPs) within the β₁- (Ser49Gly, Arg389Gly) and β₂-adrenoceptor (Arg16Gly, Gln27Glu, Thr164Ile) have been associated with alterations in adrenoceptor (AR) function sensitivity in vitro and in vivo and possibly contribute to HF progression. The present study evaluated the relation of those SNPs to morbidity and mortality in patients with end-stage HF. A total of 226 patients with end-stage HF (ejection fraction ≤35%) were genotyped for the two β₁AR SNPs and the three β₂AR SNPs. Outcome (death, heart transplantation (HTX)) was determined from May 2003 to June 2004. Heart rate, systolic and diastolic blood pressure, and peak oxygen uptake were measured during graded treadmill exercise. Left ventricular end-diastolic and end-systolic diameters, ejection fraction, and fractional shortening at rest were measured using two-dimensional echocardiography. Minor allele frequencies were 0.12 for Gly49 and 0.27 for Gly389 (β₁AR) and 0.37 for Arg16, 0.43 for Glu27 and 0.01 for Ile164 (β₂AR). During follow-up, 45 patients died (20%), and 27 patients underwent HTX (12%). No significant differences in the incidence or in the time-to-endpoint of death and HTX between genotypes of the different SNPs within the β₁- and β₂AR were detected. However, patients carrying the Arg16-β₂AR tended to have lower exercise capacity and a higher probability for death/HTX within 45 months (survival proportion 46%) than patients carrying the Gly16Gly-β₂AR (survival proportion 64%). In conclusion, the Arg16Gly-β₂AR might impact on exercise capacity and outcome in end-stage heart failure.     

Depletion of autoreactive immunologic memory followed by autologous hematopoietic stem cell transplantation in patients with refractory SLE induces long-term remission through de novo generation of a juvenile and tolerant immune system

Clinical trials have indicated that immunoablation followed by autologous hematopoietic stem cell transplantation (ASCT) has the potential to induce clinical remission in patients with refractory systemic lupus erythematosus (SLE), but the mechanisms have remained unclear. We now report the results of a single-center prospective study of long-term immune reconstitution after ASCT in 7 patients with SLE. The clinical remissions observed in these patients are accompanied by the depletion of autoreactive immunologic memory, reflected by the disappearance of pathogenic anti-double-stranded DNA (dsDNA) antibodies and protective antibodies in serum and a fundamental resetting of the adaptive immune system. The latter comprises recurrence of CD31(+)CD45RA(+)CD4(+) T cells (recent thymic emigrants) with a doubling in absolute numbers compared with age-matched healthy controls at the 3-year follow-up (P = .016), the regeneration of thymic-derived FoxP3(+) regulatory T cells, and normalization of peripheral T-cell receptor (TCR) repertoire usage. Likewise, responders exhibited normalization of the previously disturbed B-cell homeostasis with numeric recovery of the naive B-cell compartment within 1 year after ASCT. These data are the first to demonstrate that both depletion of the autoreactive immunologic memory and a profound resetting of the adaptive immune system are required to reestablish self-tolerance in SLE.     

The influence of various registration procedures upon surgical accuracy during navigated controlled petrous bone surgery

Objective

The goal of this study was to investigate the dependence of surgical accuracy with a navigated controlled (NC) drill on selected registration procedures.

Study design

The target registration error of the instrument and the maximum proximity to a typical high-risk structure (facial nerve) were determined within an artificial petrous bone.

Setting

The studies took place in two groups: group 1, navigation bow with six integrated markers and attachment at the upper jaw, and group 2, landmark registration with four titanium microscrews. Measurement of the target registration error took place at three targets (3 titanium screws) with 20 repeated registration procedures via evaluation of the deviation between a target and the indicated position in the navigation data.

Subjects and Methods

For measurement of the conversion accuracy of the planned cavity, 20 petrous bone models were milled by inexperienced test subjects. The evaluation of 20 cavities was conducted via a microscope by five jurors.

Results

Registration accuracy showed a maximum deviation between the actual position achieved and the computed position in the navigation system of 1.73 mm in group 1 and 0.93 mm in group 2. In group 1, the nerve in five of 20 cases was damaged, and a maximum penetration into the nerve of 1.5 mm (0.25 mm SD; milled beyond) was measured. In group 2, the facial nerve was not damaged at all, and a maximum deviation of 0.5 mm (0.63 mm SD; stopped before) was measured.

Conclusion

The results for registration and conversion accuracy are significantly better for the landmark-based registration than with the registration of the patient model with registration bow on the upper jaw.     

Long-Term Results of Heart Transplantation for End-Stage Valvular Heart Disease

Abstract   Background: In general, heart transplantation for patients with heart failure improves survival. However, the outcomes of heart transplantation for patients with end-stage valvular heart disease are less well reported. This is a substantial group of patients, many of whom have had previous cardiac surgery. They therefore may be considered a subgroup with a poor prognosis. This study reports on the outcomes of heart transplantation for patients with end-stage valvular heart disease. Patients and methods: From March 1989 to December 2004, 75 consecutive adult heart transplantations were performed for end-stage valvular heart disease. Clinical characteristics were retrieved from a computerized database. Results: The early mortality risk in heart transplantation for end-stage valvular heart disease was 13%, compared to 8% for other indications (p = 0.12). The main causes of early death were rejection (20%) and right ventricular failure (20%). The total follow-up time was 415 patient-years. During the follow-up, another 23 patients died (55/1000 patient-years of late mortality rate), mostly due to infection (43%) and multiorgan failure (22%). Multivariable analysis demonstrated that increased waiting time to heart transplantation correlated with increased survival (HR = 0.998, p = 0.04). The survival at 1, 5, 10, and 15 years was 70%, 64%, 56%, and 46% compared to 78%, 68%, 53%, and 41% for other indications, respectively (p = 0.5). Conclusion: The outcomes of heart transplantation for patients with end-stage valvular heart disease are similar to those for other patients. Apparently, the longer the waiting time to heart transplantation the better the outcome becomes.