Porcine Animal Model Research Articles

Feasibility of endoscopic transgastric distal pancreatectomy in a porcine animal model

In contrast to laparoscopic tubal ligation, oophorectomy, and appendectomy, laparoscopic distal pancreatectomy is associated with a morbidity rate of more than 50% and a mortality rate of more than 3%. To develop a minimally invasive, transgastric endoscopic technique for distal pancreatectomy in a nonsurvival series in swine. Experimental study. Animal trial at a tertiary-care academic hospital. Six healthy Yorkshire swine under general anesthesia. A double-channel gastroscope was introduced into the stomach, and a gastric incision was created by using a triple-lumen, 4-mm, cutting-wire needle knife. The peritoneal cavity was accessed. An Endoloop was placed endoscopically around the distal aspect of the pancreas, and the tail of the pancreas was transected by using a diathermic snare. One to 3 hemoclips were placed across the pancreatic duct. The pancreatic specimen was retrieved, and the gastrotomy was closed endoscopically with metal clips. The animals were euthanized after the procedure. The abdominal cavity was examined grossly, and the resected pancreas was examined histologically. Feasibility of endoscopic transgastric distal pancreatectomy and rate of complications. The pancreatic tail was successfully resected via a transgastric endoscopic approach in all animals. The procedure took an average (standard deviation) of 77.3 +/- 18.9 minutes. There was 1 complication, an episode of bleeding from a splenic laceration, which resulted in the loss of 250 mL of blood. Nonsurvival series, animal study. Transgastric endoscopic distal pancreatectomy is technically feasible and can be performed in the porcine animal model.

Notes: The Hybrid Technique

Natural orifice translumenal endoscopic surgery (NOTES) has gained much interest by minimal invasive surgeons and gastroenterologists. Performing abdominal operations without any abdominal wall incisions may offer all the advantages of minimally invasive surgery (MIS) and eliminate the complications associated with these wounds. The NOTES technique is rapidly being developed, but one of the major issues involved in the procedure that has to be addressed prior to implementation is in obtaining adequate spatial orientation. The aim of this study was to combine the standard laparoscopic vision together with the endoscopic surgery procedure in order to acquire an independent satisfactory vision source. The hybrid technique was performed in 6 porcine animal models. Among the procedures performed were tubal ligation, liver biopsies, oophorectomy, and cholecystectomy. All procedures were performed under general anesthesia, and all animals were euthanized at the termination of the procedure. The laparoscopic vision offers substantial advantages over the endoscopic vision. Spatial orientation is achieved in the same manner and quality as in MIS, and furthermore, the laparoscopic vision increases the safety of the NOTES procedure. The hybrid technique offers a superior vision source independent to the working endoscope. It may be an interim technique for developing NOTES until a novel imaging device will be available, or serve as the final solution for acquiring an adequate vision for this approach.

Functional and Histological Changes after Myoblast Injections in the Porcine Rhabdosphincter

ObjectiveTransurethral ultrasound-guided injection of autologous myoblasts has recently been shown to cure urinary stress incontinence. In the present study, the dose-dependent changes in maximal urethral closure pressures after application of myoblasts were investigated in a porcine animal model. MethodsMyoblast cultures were grown from a porcine muscle biopsy. The biopsy was enzymatically dissociated by using a modified cell dispersion technique. Single myoblasts in suspension were manually collected with a micropipette under microscopic control. Next a clonal myoblast culture was prepared. Before the cells were applied, fluorescence labelling (PKH) was used to assess integration of the injected myoblasts into the rhabdosphincter. With the help of a transurethral ultrasound probe (23 F, 11MHz) and a special injection system, the myoblasts were injected into the rhabdosphincter of five pigs under direct sonographic control. Into two different areas of the rhabdosphincter, increasing different cell counts were injected (total volume 1.5ml). At each area, 10 depots of 150μl volume were injected all along the rhabdosphincter. The following cell counts were used: 1.5×106, 2.1×106, 4.2×106 (low range) 5.69×106, 8.1×106, 1.13×107, 1.6×107 (mid range) 2.26×107, 4.4×107, and 7.8×107 (high range). To avoid possible cell rejection, we immunosuppressed the pigs with daily cortisone (1g Solu Dacortin) because allogenic myoblasts were used. Urethral pressure profiles (UPPs) were measured before and 3 wk postoperatively before the pigs were put to sleep. The lower urinary tract was removed in all pigs for histological analysis. ResultsHistological examination of the specimens revealed that the injected cells had survived at the injection site and had formed new myofibres. Overall the UPP curves revealed dose-dependent changes. Statistically significant increased pressure values of up to more than 300% could be observed in all cases in which higher concentrations of cells had been applied. Increases were also noted in mid range concentrations although not to such a high extent (approximately 150%). Pressure values had even diminished (approximately 50%) after injecting the three lowest concentrations (1.5×106, 2.1×106, 4.2×106). ConclusionsThe present results show that the effects after application of myoblasts into the rhabdosphincter are dose-dependent.

The effect of osmotic stress on the cell volume, metaphase II spindle and developmental potential of in vitro matured porcine oocytes

Porcine animal models are used to advance our understanding of human physiology. Current research is also directed at methods to produce transgenic pigs. Cryobanking gametes and embryos can facilitate the preservation of valuable genotypes, yet cryopreserving oocytes from pigs has proven very challenging. The current study was designed to understand the effects of anisotonic solutions on in vitro matured porcine oocytes as a first step toward designing improved cryopreservation procedures. We hypothesized that the proportion of oocytes demonstrating a normal spindle apparatus and in vitro developmental potential would be proportional to the solution osmolality. Oocytes were incubated for 10 min at 38 °C in various hypo- or hypertonic solutions, and an isotonic control solution and then assessed for these two parameters. Our results support the hypothesis, with an increasing proportion of spindles showing a disrupted structure as the levels of anisotonic exposure diverge from isotonic. Only about half of the oocytes maintained developmental potential after exposure to anisotonic solutions compared to untreated controls. Oocyte volume displayed a linear response to anisotonic solutions as expected, with an estimated relative osmotically inactive cell volume of 0.178. The results from this study provide initial biophysical data to characterize porcine oocytes. The results from future experiments designed to determine the membrane permeability to various cryoprotectants will allow predictive modeling of optimal cryopreservation parameters and provide a basis for designing improved cryopreservation procedures.

Comparative Study of Degree of Renal Trauma Between Amplatz Sequential Fascial Dilation and Balloon Dilation During Percutaneous Renal Surgery in an Animal Model

To compare two commonly used methods of dilation, the Amplatz sequential fascial (ASF) and the balloon dilator, in a porcine model. Fourteen kidneys from 9 female pigs were used for this experiment. One kidney of each pig underwent ASF dilation and the other underwent balloon dilation using the Nephromax balloon. This was achieved after percutaneous renal puncture with an 18-gauge needle under fluoroscopic guidance. The effects of both methods of dilation were assessed immediately in 1 pig, after 24 hours in 3 pigs, at 4 weeks in 4 pigs, and at 6 weeks in 1. The animals were killed, and the kidneys were removed for gross and histologic examination. Grossly, the ASF dilated tracts appeared rounded and the balloon dilated tracts appeared V-shaped with lateral fragmentation within 24 hours. No obvious gross differences were noted at 4 to 6 weeks between the two methods of dilation, with both appearing as fine scars. Histologically, minor differences were seen at 4 to 6 weeks, with slightly more abscesses and larger scar formation in the kidneys that underwent ASF dilation than in the balloon dilation group. In this porcine animal model, the degree of renal trauma induced by the ASF dilators and the balloon dilators during percutaneous renal surgery seems to be comparable. The acute and chronic renal parenchyma effects of both methods of tract dilation were almost similar. The choice of nephrostomy tract dilation should be by physician preference.

An In Vivo Mobile Robot for Surgical Vision and Task Assistance

Current laparoscopic surgical robots are expensive, bulky, and fundamentally constrained by the small entry incisions. A potential new approach to minimally invasive surgery is to place the robot completely within the patient. We have developed several such miniature mobile robots and conducted tests during animal surgeries. These robots can provide vision and task assistance to the surgeon without being constrained by the entry port. We used a mobile biopsy and camera robot to sample hepatic tissue from an anesthetized porcine animal model. This successful test demonstrated the capability of performing a single port laparoscopic biopsy procedure. In the future, a family of such robots could be remotely controlled and used to perform surgical procedures without the need for conventional laparoscopic tools.

Analysis of apoptotic cell death, Bcl-2, and p53 protein expression in freshly fixed and cryopreserved ovarian tissue after exposure to warm ischemia

To evaluate the effect of ischemia time on the expression of Bcl-2 and p53 proteins on freshly fixed and cryopreserved-thawed ovarian tissue. Experimental study using porcine animal model. Biological Resources Unit, Cleveland Clinic Foundation. Eight nonpregnant adult sows. Bilateral oophorectomy was performed in eight sows and the ovaries were subjected to time-dependent (1, 10, 20, and 30 min) warm ischemia (room temperature). Each specimen was divided into two parts, One was fixed as a fresh tissue (freshly fixed) and the other was subjected to cryopreservation, thawing, and fixation (cryopreserved). Apoptosis (TUNEL assay) and Bcl-2 and p53 protein expression (immunoperoxidase method) were assessed. At 1, 10, 20, 30 min of warm ischemia the apoptotic indices were: 1) statistically significantly higher in the atretic (1.36 +/- 0.20, 1.59 +/- 0.20, 1.67 +/- 0.22, and 1.67 +/- 0.24, respectively) than in the nonatretic follicles (0.69 +/- 0.06, 0.69 +/- 0.06, 0.76 +/-, and 0.06, 0.71 +/- 0.06, respectively; P<.05); 2) not significantly different between freshly fixed and cryopreserved tissues; and 3) nonsignificantly higher with the increased duration of ischemia. Bcl-2 expression was seen in the granulosa but not in the theca cells of most of the healthy and occasional atretic follicles. p53 expression was seen only in few atretic follicles. Increased duration of ischemia was associated with insignificant incremental rise of the number of follicles with Bcl-2 expression (1.82 +/- 0.30, 2.01 +/- 0.44, 2.02 +/- and 0.35, 2.05 +/- 0.42 for healthy follicles at 1, 10, 20, and 30 min, respectively; P=.99). (1) Apoptosis is involved in follicular atresia; (2) Bcl-2 is induced by warm ischemia; and (3) cryopreservation insult does not alter the apoptotic signals with short tissue preparation time.

Evaluation of a bioresorbable polylactide sheet for the reduction of pelvic soft tissue attachments in a porcine animal model

In an adult porcine model, the effectiveness of a bioresorbable film to minimize soft tissue attachment to the pelvic viscera was evaluated at 4-week and 12-week endpoints. Following a transperitoneal laparotomy through a midline incision, the bladder and uterus were abraded in all animals to promote soft tissue attachment to the viscera. Control animals received no further treatment. The experimental group animals were treated with bioresorbable polylactide (PLa) sheets, 0.02 mm thick, one between the bladder and the abdominal wall, and a second sheet between the bladder and the uterus. Quantitative assessment of the severity and location of soft tissue attachments, and qualitative histologic assessment were performed at 4 and 12 weeks post-operatively. Statistically significant differences in the quantitative soft tissue attachment scores were observed in comparing the PLa film treated animals versus the control animals, at both the 4-week and 12-week time points. In the control animals, the formation of numerous thick fibrous bands was observed at both time points. Histology revealed no adverse reaction to the bioresorbable PLa barrier film. The bioresorbable PLa sheet provided an effective barrier between adjacent anatomical structures and minimized soft tissue attachments to the device when in contact with the viscera as compared to the control groups. Surgical dissection planes between the abdominal wall and adjacent soft tissues were maintained with the use of the PLa sheet at both time points.

Elicitation of strong immune responses by a DNA vaccine expressing a secreted form of hepatitis C virus envelope protein E2 in murine and porcine animal models

To characterize the immunogenicity of a hepatitis C virus (HCV) E2 DNA vaccine alone or with a protein vaccine boost in murine and porcine animal models. A DNA vaccine expressing a secreted form of HCV E2 protein was constructed and used to vaccinate mice and piglets with or without boosting with a recombinant E2 protein vaccine formulated with CpG ODN and 10% Emulsigen. The immunogenicity of HCV E2 vaccines was analyzed by ELISA for antibody responses, MTT assay for lymphocyte proliferation, ELISPOT for the number of interferon-gamma secreting cells, and cytotoxic T lymphocyte assays. Intradermal injection of E2 DNA vaccine induced strong Th1-like immune responses in mice. In piglets, E2 DNA vaccine elicited moderate and more balanced immune responses. A DNA vaccine prime and protein boost vaccination strategy induced significantly higher E2-specific antibody levels and shifted the immune response towards Th2-like ones in piglets. A DNA vaccine expressing a secreted form of HCV E2 protein elicited E2-specific immune responses in mice and piglets. Recombinant E2 protein vaccination following DNA immunization significantly increased the antibody response in piglets. These HCV E2 vaccines may represent promising hepatitis C vaccine candidates for further investigations.

Nitinol Carbofilm coated stents for peripheral applications: Study in the porcine model

Testing the safety and foreign body reaction (FBR) of a nitinol self-expandable carbon-coated stent system in the porcine animal model at different follow-up (FU) periods. Fifteen minipigs received 30 carbon-coated self-expandable nitinol stents in iliac arteries. Explants were carried out at 7 (3 animals), 30 (4 animals), 90 (4 animals) and 180 (4 animals) day FU, for evaluation of acute, sub-acute and chronic biological response to the implanted devices. Histological, immunohistochemical, histomorphometric and scanning electron microscopy (SEM) analyses were performed to assess inflammatory reaction, endothelialization process, neointimal growth and cellular composition. Thirty stents were successfully implanted. No mural thrombi were observed at gross examination or by angiography. Histologically no significant inflammatory reaction was detected: the stents appeared covered by a thin monolayer of endothelial cells even at 7 day FU. The neointima presented homogeneous growth and moderate thickness after 30, 90 and 180 days explants (0.38+/- 0.36 mm, 0.33+/- 0.30 mm, 0.27+/- 0.25 mm respectively). Internal and external elastic laminae were intact in 95% of stented arteries. Histological data validations of vessel endothelialization was obtained with SEM for the seven day follow-up group. This study showed good remarkable technical performances, minimal FBR and biocompatibility comparable with other available pre-clinical experimentations.

1203 Strain and strain rate imaging to monitor the effect of intracoronary transplantation of labelled mesenchymal stem cells post myocardial infarction in a porcine animal model

1203 Strain and strain rate imaging to monitor the effect of intracoronary transplantation of labelled mesenchymal stem cells post myocardial infarction in a porcine animal model

A Portable Cardiopulmonary Bypass/Extracorporeal Membrane Oxygenation System for the Induction and Reversal of Profound Hypothermia: Feasibility Study in a Swine Model of Lethal Injuries

The Cleveland Clinic Foundation's (CCF) cardiopulmonary bypass/extracorporeal membrane oxygenation (CPB/ECMO) system capabilities were tested in a hypothermia trauma management feasibility study in a porcine animal model at the Uniformed Services University of the Health Sciences (USUHS, Bethesda, MD, U.S.A.). In this survival series, the CCF system was used in a simulated forward lines combat casualty application where lethal uncontrolled hemorrhage from major vascular injuries was repaired under a state of profound hypothermic arrest (suspended animation), followed by recovery and monitoring in an intensive care unit (ICU) setting. The animals were monitored for survival, neurological impact, cognitive functions, organ damage, and delayed complications over 3 weeks. A survival rate of 83% matched rates previously found using conventional equipment. Neurological findings, organ dysfunction, and complication rates also were no different from previous studies using standard equipment. Successful survival results demonstrated that the CCF CPB/ECMO system could be used to induce a period of profound hypothermic arrest for the repair of lethal traumatic injuries. The logistical advantages of this system make it an attractive choice for use in austere settings and during transport.

No Magic Bullet: Tungsten Alloy Munitions Pose Unforeseen Threat

Vol. 113, No. 6 EnvironewsOpen AccessNo Magic Bullet: Tungsten Alloy Munitions Pose Unforeseen Threatis accompanied byEmbedded Weapons-Grade Tungsten Alloy Shrapnel Rapidly Induces Metastatic High-Grade Rhabdomyosarcomas in F344 Rats Charles W. Schmidt Charles W. Schmidt Search for more papers by this author Published:1 June 2005https://doi.org/10.1289/ehp.113-a403aCited by:2AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit In response to concerns about the human and environmental health effects of materials used to produce munitions, countries including the United States have begun replacing some lead- and depleted uranium–based munitions with alternatives made of a tungsten alloy. But this solution may not be the “magic bullet” it was once envisioned to be. Researchers from the Armed Forces Radiobiology Research Institute and the Walter Reed Army Institute of Research now report that weapons-grade tungsten alloy produces aggressive metastatic tumors when surgically implanted into the muscles of rats [EHP113:729–734]. These findings raise new questions about the possible consequences of tungsten exposure, and undermine the view that tungsten alloy is a nontoxic alternative to depleted uranium and lead.In the study, male F344 rats were implanted with pellets in each hind leg, an exposure protocol that mimicked shrapnel wounds received in the field. The rats were split into four treatment groups: a negative control implanted with 10 pellets of tantalum (an inert metal), a positive control implanted with 10 pellets of nickel (a known carcinogen), a high-dose group implanted with 10 pellets of tungsten alloy, and a low-dose group implanted with 4 pellets of tungsten alloy and 16 pellets of tantalum. The alloy used in this research was the same as that used in weapons: 91.1% tungsten, 6.0% nickel, and 2.9% cobalt.By 6 months after implantation all the rats in the high-dose, low-dose, and positive control groups had developed leg tumors. None of the rats in the negative control developed tumors, and all survived beyond 12 months with no apparent health effects. All remaining rats were sacrificed at 24 months.At sacrifice, blood samples were assessed for a range of hematologic parameters. The high-dose group exhibited statistically significant increases in levels of white blood cells, red blood cells, hemoglobin, and hematocrit as compared to the low-dose and control groups.The rats also underwent a pathology exam, and tissues were collected for histology. Whereas the tantalum pellets in the low-dose group were surrounded by normal tissue, all of the tungsten alloy and nickel pellets were surrounded by tumors. Tumors in the tungsten alloy–treated animals metastasized to the lung. Histology further indicated that tungsten alloy pellets were surrounded by invasive neoplastic cells that had infiltrated into skeletal muscle tissue. No metastasis was observed in the positive controls.Organ measurements identified significant increases in both spleen and thymus body-to-weight ratios in the high-dose group only. Both these organs are components of the immune system, leading the authors to suggest that embedded tungsten alloy may be immunotoxic at certain concentrations.The authors write that the amounts of cobalt (a suspected human carcinogen) and nickel in the tungsten alloy material likely were too small to produce the effects seen in the two groups implanted with the alloy. However, they do cite recent evidence indicating that the combination of these metals may produce synergistic effects. The biological mechanism by which embedded tungsten alloy produces tumors is unclear, they add, and warrants further study.“Better” bullets? New data show that tungsten alloy, used in munitions in hopes it would be an environmentally friendlier alternative to lead and depleted uranium, causes tumors in animals.FiguresReferencesRelatedDetailsCited by Griffiths M (2021) The geontological time-spaces of late modern war, Progress in Human Geography, 10.1177/03091325211064266, 46:2, (282-298), Online publication date: 1-Apr-2022. Sarber K, O’Connor P, Weitzel E, Stevens J, Aden J and Breeze J (2022) Local Effect of Ballistic Fragments Embedded Along the Carotid Sheath of a Porcine Animal Model, Military Medicine, 10.1093/milmed/usac276 Related articlesEmbedded Weapons-Grade Tungsten Alloy Shrapnel Rapidly Induces Metastatic High-Grade Rhabdomyosarcomas in F344 Rats15 February 2005Environmental Health Perspectives Vol. 113, No. 6 June 2005Metrics About Article Metrics Publication History Originally published1 June 2005Published in print1 June 2005 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

The Miniature Pig as an Animal Model in Biomedical Research

Crucial prerequisites for the development of safe preclinical protocols in biomedical research are suitable animal models that would allow for human-related validation of valuable research information gathered from experimentation with lower mammals. In this sense, the miniature pig, sharing many physiological similarities with humans, offers several breeding and handling advantages (when compared to non-human primates), making it an optimal species for preclinical experimentation. The present review offers several examples taken from current research in the hope of convincing the reader that the porcine animal model has gained massively in importance in biomedical research during the last few years. The adduced examples are taken from the following fields of investigation: (a) the physiology of reproduction, where pig oocytes are being used to study chromosomal abnormalities (aneuploidy) in the adult human oocyte; (b) the generation of suitable organs for xenotransplantation using transgene expression in pig tissues; (c) the skin physiology and the treatment of skin defects using cell therapy-based approaches that take advantage of similarities between pig and human epidermis; and (d) neurotransplantation using porcine neural stem cells grafted into inbred miniature pigs as an alternative model to non-human primates xenografted with human cells.

Single cell electrophoresis in determining cell death: Potential for use in organ transplant research

Viability of donor tissues is essential for the success of organ transplantation. Although much work has been done in the field of organ preservation, currently there are few objective methods for evaluating transplant organ viability, and thus preservation efficiency. In the field of cancer biology, single-cell gel electrophoresis (SCGE) is a technique commonly used to measure the efficacy of anti-tumor treatments by measuring the breakdown of tumor cell deoxyribonucleic acid (DNA). This assay has recently been applied to various organs from a postmortem porcine animal model, and cells were found to undergo postmortem breakdown in a way similar to apoptosis-induced DNA fragmentation. Collections of cells from each organ reached levels indicative of non-viability as the postmortem interval (PMI) progressed. The rates of cellular DNA degradation were found to be specific to each organ type at a given ambient temperature. We believe that following the application of various preservation techniques, SCGE assay has the potential to provide a clear indication of cell viability in an organ destined for transplant. As a readily available viability assay, this technique could provide transplant researchers with a useful tool to quantify the efficacy of their experimental organ preservation techniques.

Comparison of the ovine and porcine animal models for biocompatibility testing of vascular prostheses

Evaluation of the pig and sheep models for biocompatibility investigations of vascular prostheses (VP). Comparative analysis of animal experimental investigations involving two different animal models. Commercially available polyester vascular prostheses (PET-VP) were implanted into two different animal models (infrarenal porcine aorta and ovine carotid artery). The costs, surgical handling, patency rate, and healing on the basis of macroscopic, microscopic, and immunohistochemical criteria were analyzed over a period of 3 months. Handling and operating times (63 +/- 10 versus 76 +/- 16 min; P = 0.125) did not differ significantly. The cost of the two animal models was comparable. Integration of the VP was complete in the sheep model, but varied in the pig model (two complete, four incomplete). Complete endothelialization of all VPs was observed in the pig, which contrasted with the sheep with complete (circular) endothelialization only in the region of the anastomosis. The thickness of neointima in the region of the anastomosis differed insignificantly; immunohistochemically, only periprosthetic Ki67 was significantly reduced (28.7 +/- 9.9 versus 6 +/- 0.9%; P = 0.002) in the sheep. In the porcine model, extremely good endothelialization of the VP was observed, with formation of a rapid neointimal hyperplasia. The ovine model was characterized by the fact that postoperative follow-up investigations were easy to perform. Complete endothelialization was not observed.

Predicting baseline laparoscopic surgery skills

Laparoscopic surgery requires specialized dexterity even beyond that required for open surgery. Decreased tactile feedback, different eye-hand coordination, and translation of a two-dimensional video image into a three-dimensional working area are just some of the obstacles in the performance of laparoscopic surgery. Possession of certain nonsurgical skills may help in overcoming some of these obstacles. Prediction of baseline laparoscopic surgery skills may help further to refine the education of basic laparoscopic surgery skills. This investigation explores whether nonsurgical skills and demographic data can predict baseline laparoscopic surgery tasks. First- and second-year students were given a survey regarding nonsurgical dexterity skills. The survey inquired about typing skills, play with computer games, ability to sew, skill with music instruments, use of chopsticks, and experience operating tools. Demographic data were requested as well. All the students underwent four tasks: placing a piece of bowel in a retrieval bag, placing a stapler on the bowel, measuring a piece of bowel, and performing a liver biopsy in a porcine animal model. Both objective (time and error) and subjective evaluation were assessed for all the tasks. Statistical analysis using analysis of variances (ANOVA) Kruskal-Wallis test with post hoc tests, two-tailed unpaired t-tests/Mann-Whitney test, and Fischer's exact tests/chi-square tests was performed when appropriate. There were 68 students in this investigation. Gender, medical student year, ethnicity, desire to enter a surgical field, and age were not associated with increased performance in any of the tasks. Chopstick use was associated with statistically significantly better mean time in placing a piece of bowel in a retrieval bag and measuring a piece of bowel (p < 0.04). The other nonsurgical dexterity skills did not statistically increase performance, as indicated by time, errors, or subjective scores, for the four tasks. It is difficult to predict baseline laparoscopic surgery skills.

Detection of changes in articular cartilage proteoglycan by T1 ρ magnetic resonance imaging

The purpose of this work is to demonstrate the feasibility of T 1 ρ -weighted magnetic resonance imaging (MRI) to quantitatively measure changes in proteoglycan content in cartilage. The T 1 ρ MRI technique was implemented in an in vivo porcine animal model with rapidly induced cytokine-mediated cartilage degeneration. Six pigs were given an intra-articular injection of recombinant porcine interleukin-1β (IL-1β) into the knee joint before imaging to induce changes in cartilage via matrix metalloproteinase (MMP) induction. The induction of MMPs by IL-1 was used since it has been extensively studied in many systems and is known to create conditions that mimic in part characteristics similar to those of osteoarthritis. The contralateral knee joint was given a saline injection to serve as an internal control. T 1 ρ -weighted MRI was performed on a 4 T whole-body clinical scanner employing a 2D fast spin-echo-based T 1 ρ imaging sequence. T 1 ρ relaxation parameter maps were computed from the T 1 ρ -weighted image series. The average T 1 ρ relaxation rate, R 1 ρ (1/ T 1 ρ ) of the IL-1β-treated patellae was measured to be on average 25% lower than that of saline-injected patellae indicating a loss of proteoglycan. There was an average reduction of 49% in fixed charge density, measured via sodium MRI, of the IL-1β-treated patellae relative to control corroborating the loss of proteoglycan. The effects of IL-1β, primarily loss of PG, were confirmed by histological and immunochemical findings. The results from this study demonstrate that R 1 ρ is able to track proteoglycan content in vivo.

PARTIAL NEPHRECTOMY WITH FIBRIN GLUE REPAIR: MEASUREMENT OF VASCULAR AND PELVICALICEAL HYDRODYNAMIC BOND INTEGRITY IN A LIVE AND ABBATOIR PORCINE MODEL

Some of the challenges during partial nephrectomy include control of bleeding and repair of the pelvicaliceal system. Fibrin tissue sealants have recently been used to achieve hemostasis and collecting system closure in open and laparoscopic partial nephrectomy. However, there exist little data regarding the intrinsic strength of the bond, especially when applied to the vasculature and the urinary collecting system of the transected kidney. We examined the hydrodynamic bond integrity of a commercially available fibrin tissue sealant in a live porcine animal model undergoing partial nephrectomy. Open partial nephrectomy was performed in 19 porcine renal units. Collecting system entry was confirmed by methylene blue instillation into the proximal ureter. Fibrin tissue sealant was used to repair 16 renal units, that is 8 kidneys hardened in vivo for 10 minutes and 8 hardened in vivo for 60 minutes. In an additional 3 renal units monopolar electrocautery was used to achieve hemostasis (no fibrin glue used). The strength of vasculature repair was performed by infusing saline into the renal artery (renal vein ligated) and measuring pressure at bond rupture. Similarly the integrity of pelvicaliceal repair was evaluated by retrograde infusion of saline into the collecting system via the proximal ureter and measurement of pressure at bond rupture. Fibrin tissue sealant was successful in achieving prompt hemostasis and it was subjectively superior to cautery alone with regard to bleeding control. Mean renal vascular and pelvicaliceal burst pressure for fibrin sealant treated kidneys was 378 (median 420) and 166 mm Hg (median 170), respectively. There was no significant difference in 10 vs 60-minute hardening times in treated kidneys. In comparison, vascular and pelvicaliceal burst pressure for nontreated (cautery alone) kidneys was 230 (median 220) and 87 mm Hg (median 90), respectively. Commercially available fibrin tissue sealants can provide supraphysiological renal parenchyma and collecting system sealing pressures after partial nephrectomy. This information supports the potential use of fibrin sealants during open and laparoscopic partial nephrectomy.

Estratégia de capacitação em cirurgia palpebral baseada em modelo animal

OBJETIVO: Desenvolvimento de método de treinamento prático em cirurgia palpebral baseado em modelo animal, orientado para o oftalmologista geral e para o iniciante em cirurgia palpebral. MÉTODOS: O modelo porcino foi selecionado devido à semelhança com relação à pálpebra humana. Após breve estudo dirigido com material didático abordando aspectos básicos em cirurgia palpebral e roteiro prático detalhado dos procedimentos a serem realizados, passou-se ao treinamento prático. As técnicas de cirurgia palpebral abordadas foram ressecção pentagonal com reconstrução direta e por planos da pálpebra e técnica original de Bick. O treinamento foi monitorizado cuidadosamente por instrutores com ampla experiência no assunto. Cada aluno tinha à disposição 4 pálpebras. RESULTADOS: Quatorze oftalmologistas foram treinados por meio deste modelo no 1º Curso de Cirurgia Palpebral em Animal em dezembro de 2001. Ao final do treinamento, os alunos se mostraram mais confiantes na realização dos procedimentos realizados, acreditando que a experiência havia contribuído positivamente para o desenvolvimento prático em cirurgia palpebral. CONCLUSÃO: O modelo animal porcino de treinamento pode ser etapa valiosa na transição da esfera teórica para a habilitação prática em Plástica Ocular, e pode ser utilizado como estratégia eficaz na capacitação em ressecção pentagonal com reconstrução direta e por planos da pálpebra e técnica original de Bick.