Performance of basic manipulation and intracorporeal suturing tasks in a robotic surgical system: single- versus dual-monitor views

Background  Technical advances in the application of laparoscopic and robotic surgical systems have improved platform usability. The authors hypothesized that using two monitors instead of one would lead to faster performance with fewer errors. Methods  All tasks were performed using a surgical robot in a training box. One of the monitors was a standard camera with two preset zoom levels (zoomed in and zoomed out, single-monitor condition). The second monitor provided a static panoramic view of the whole surgical field. The standard camera was static at the zoomed-in level for the dual-monitor condition of the study. The study had two groups of participants: 4 surgeons proficient in both robotic and advanced laparoscopic skills and 10 lay persons (nonsurgeons) who were given adequate time to train and familiarize themselves with the equipment. Running a 50-cm rope was the basic task. Advanced tasks included running a suture through predetermined points and intracorporeal knot tying with 3–0 silk. Trial completion times and errors, categorized into three groups (orientation, precision, and task), were recorded. Results  The trial completion times for all the tasks, basic and advanced, in the two groups were not significantly different. Fewer orientation errors occurred in the nonsurgeon group during knot tying (p = 0.03) and in both groups during suturing (p = 0.0002) in the dual-monitor arm of the study. Differences in precision and task error were not significant. Conclusions  Using two camera views helps both surgeons and lay persons perform complex tasks with fewer errors. These results may be due to better awareness of the surgical field with regard to the location of the instruments, leading to better field orientation. This display setup has potential for use in complex minimally invasive surgeries such as esophagectomy and gastric bypass. This technique also would be applicable to open microsurgery. Presented at the 2008 SAGES meeting.     

Raman spectroscopy detects and distinguishes neuroblastoma and related tissues in fresh and (banked) frozen specimens

Background

Raman spectroscopy has been shown to accurately distinguish different neural crest-derived pediatric tumors. This study tests the ability of Raman spectroscopy to accurately identify cryopreserved tissue specimens using a classification algorithm designed from fresh tumor data and vice versa.

Methods

Fresh specimens of neuroblastoma and other pediatric neural crest tumors were analyzed with Raman spectroscopy. After analysis, the specimens were stored at −80°C. At a later date, the specimens were thawed and reanalyzed by Raman spectroscopy. A computer algorithm was used to classify the spectra from the frozen tissue against a computer model built on the fresh tissue data. This classification process was then reversed, testing fresh spectra against a model built from frozen data.

Results

We collected 1114 spectra (862 fresh and 252 frozen) from 62 tissue samples, including 8 normal adrenal glands, 29 neuroblastomas, 14 ganglioneuromas, 8 nerve sheath tumors, and 3 pheochromocytomas. At the tissue level, frozen neuroblastoma, ganglioneuroma, nerve sheath tumor, and pheochromocytoma were distinguished from normal adrenal tissue with 100% sensitivity and specificity. Fresh tissue had the same results except for the misclassification of one specimen of nerve sheath tumor.

Conclusions

The representative spectra show a high correlation between fresh and frozen tissue, and a clear difference between pathologic conditions. Spectra from frozen tissue can be accurately classified against spectra from fresh tissue and vice versa. This modality makes it possible to determine in a few minutes a result that often takes 12 to 36 hours for tissue processing and consideration by a trained pathologist to achieve.     

Management of pediatric acute appendicitis in the computed tomographic era

BACKGROUND/PURPOSE: The treatment options for complicated appendicitis in children continue to evolve. Optimal management of complicated appendicitis relies on an accurate preoperative diagnosis. We examined the accuracy of our preoperative diagnosis including computed tomography (CT) and the influence on the management of children with perforated and nonperforated appendicitis. METHODS: Following IRB approval, a 6-year review of all patients that underwent an appendectomy for suspected appendicitis was performed. Treatments included immediate operations and initial nonoperative management (antibiotic therapy +/- percutaneous drainage of abscess). Appendicitis was confirmed by histological examination. RESULTS: One thousand seventy-eight patients underwent appendectomy for suspected appendicitis. Preoperative CT scans were performed in 697 (64.7%) patients: 615 (88.2%) positive for appendicitis; 42 (6.0%) negative; and 40 (5.7%) equivocal. One hundred seventy-three (28.1%) positive CT scans further suggested perforation. Initial nonoperative management was initiated in 39 (22.5%) cases of suspected perforated appendicitis with abscess. The positive-predictive value (PPV) for suspected acute appendicitis based on history and physical examination alone was 90.8%. The PPV for positive CT scan for acute appendicitis was 96.4% with a PPV of 91.9% for positive CT scan for perforated appendicitis. CONCLUSIONS: The correct preoperative diagnosis of appendicitis appears statistically more accurate with CT scan compared to history and physical examination alone (PPV 96.4% versus 90.8%, P = 0.045). For those with clinically suspicious complicated appendicitis, CT evaluation may direct therapy toward initial nonoperative management. The efficacy of this regimen warrants further investigation.     

Asymptomatic chronic hepatitis B virus infection in northern India.

BACKGROUND: Chronic infection with hepatitis B virus (HBV) causes a spectrum of diseases ranging from asymptomatic infective state to cirrhosis and hepato-cellular carcinoma. The asymptomatic state has highly variable characteristics. METHODS: Sixty-one incidentally detected asymptomatic HBsAg-positive subjects (IDAHS), in whom HBsAg positivity persisted for > 6 months, were studied for liver biochemistry, HBeAg, anti HBe and HBV DNA levels (in HBeAg-negative subjects). Liver biopsy was done in 29 subjects and scored for histological activity index (HAI) and fibrosis using modified Knodell score. RESULTS: Thirteen (21%) subjects were HBeAg positive. The remaining 48 (79%) were positive for anti HBe, with HBV DNA level of> 105 copies/mL in 15 (31.2%). Transaminase elevation was more frequent in HBeAg-positive subjects (69%; p< 0.05) and in HBV DNA-positive (93%) than in non-replicative (27%) infection. Seroconverted (anti HBe-positive) individuals were a decade older than HBeAg-positive ones and most (93.7%) of them were> 20 years of age. Fifteen of 29 (51.3%) had HAI> 3, more frequently in those with raised ALT (68.4%; p< 0.05) than with normal ALT (20%), but there was no difference in relation to HBeAg status. CONCLUSIONS: Seroconversion to anti HBe was noted in individuals aged 20 years or more. Ongoing liver disease was noted in approximately half of IDAHS, suggesting that a considerable proportion of IDAHS have active infection. In HBeAg-negative subjects, transaminase estimation may be sufficient in planning therapy.     

Fate of alphaGal +/+ pancreatic islet grafts after transplantation into alphaGal knockout mice

BACKGROUND: Important phylogenetic differences between pig and human tissues prevent xenotransplantation from becoming a clinically feasible option. Humans lack the galactose-alpha1,3-galactose (alphaGal) epitope on endothelial cell surfaces and therefore have preformed anti-alphaGal antibodies. The role of these antibodies in rejection of non-vascular xenografts remains controversial. This study investigated the role of anti-alphaGal antibodies in rejection of non-vascularized alphaGal+/+ grafts in alphaGal -/- mice. METHODS: alphaGal +/+ and alphaGal -/- pancreatic islets were transplanted under the renal capsule of streptozotocin-induced diabetic (1) alphaGal -/- mice and (2) alphaGal +/+ mice. alphaGal -/- recepients were immunized with rabbit red blood cell membranes (RRBCs) to produce elevated anti-alphaGal antibody levels. RESULTS: Six of the 18 alphaGal -/- mice rejected the alphaGal +/+ grafts within 68 days whereas indefinite graft survival was achieved in the control groups. Animals with surviving islet grafts were challenged with alphaGal +/+ skin grafts. Although all alphaGal +/+ skin grafts were rejected within 58 days, the islet grafts remained intact. This observation correlated with the level of alphaGal expression (which was very low on islets compared to skin) rather than the actual titre of anti-alphaGal antibody. DISCUSSION: The results suggest that the level of alphaGal expression plays an important role in graft survival. Therefore, its removal is important in the development of a pig islet donor for future clinical therapy.     

Surface-engineered liposomal particles of calcium ascorbate with fenugreek galactomannan enhanced the oral bioavailability of ascorbic acid: a randomized,double-blinded, 3-sequence,crossover study

The antioxidant, anti-inflammatory, immunomodulating, anti-thrombotic, and antiviral effects along with its protective effects against respiratory infections have generated a great interest in vitamin C (vitC) as an attractive functional/nutraceutical ingredient for the management of COVID-19. However, the oral bioavailability and pharmacokinetics of vitC have been shown to be complex and exhibit dose-dependent non-linear kinetics. Though sustained-release forms and liquid liposomal formulations have been developed, only marginal enhancement was observed in bioavailability. Here we report a novel surface-engineered liposomal formulation of calcium ascorbate (CAAS), using fenugreek galactomannan hydrogel in powder form, and its pharmacokinetics following a randomized, double-blinded, single-dose, 3-way crossover study on healthy human volunteers (n = 14). The physicochemical characterization and in vitro release studies revealed the uniform impregnation of CAAS liposomes within the pockets created by the sterically hindered galactomannan network as multilaminar liposomal vesicles with good encapsulation efficiency (>90%) and their stability and sustained-release under gastrointestinal pH conditions. Further human studies demonstrated >7-fold enhancement in the oral bioavailability of ascorbate with a significant improvement in pharmacokinetic properties (C_max, T_max, T_1/2, and AUC), compared to the unformulated counterpart (UF-CAAS) when supplemented at an equivalent dose of 400 mg of CAAS as tablets and capsules.

A green process to modulate the surface properties of liposome was reported using fenugreek galactomannan hydrogel and successfully applied to vitamin C with significant enhancement in human oral bioavailability.     

Overexpression of glutathione peroxidase with two isoforms of superoxide dismutase protects mouse islets from oxidative injury and improves islet graft function

Primary nonfunction of transplanted islets results in part from their sensitivity to reactive oxygen species (ROS) generated during the isolation and transplantation process. Our aim was to examine whether coexpression of antioxidant enzymes to detoxify multiple ROS increased the resistance of mouse islets to oxidative stress and improved the initial function of islet grafts. Islets from transgenic mice expressing combinations of human copper/zinc superoxide dismutase (SOD), extracellular SOD, and cellular glutathione peroxidase (Gpx-1) were subjected to oxidative stress in vitro. Relative viability after hypoxanthine/xanthine oxidase treatment was as follows: extracellular SOD + Gpx-1 + Cu/Zn SOD > extracellular SOD + Gpx-1 > extracellular SOD > wild type. Expression of all three enzymes was the only combination protective against hypoxia/reoxygenation. Islets from transgenic or control wild-type mice were then transplanted into streptozotocin-induced diabetic recipients in a syngeneic marginal islet mass model, and blood glucose levels were monitored for 7 days. In contrast to single- and double-transgenic grafts, triple-transgenic grafts significantly improved control of blood glucose compared with wild type. Our results indicate that coexpression of antioxidant enzymes has a complementary beneficial effect and may be a useful approach to reduce primary nonfunction of islet grafts.