Device model for training of laparoscopic surgical skills

The authors present a especially constructed, lightweight, collapsible, portable and low cost model device for skills training in laparoscopic.

Right ventricular structure and function as possible determinants of surgical outcome 30 years after repair of tetralogy of Fallot

OBJECTIVE: To identify the variables that may be involved in the persistence of symptoms (functional class II, III, or IV vs. I) in patients being followed up for 30 years after surgical repair of tetralogy of Fallot. METHODS: Fifty-three patients (27 women), who underwent corrective surgery for tetralogy of Fallot between 1960 and 1970, were studied. Their ages ranged from 7 months to 26 years. At the end of follow-up, 13 patients were asymptomatic and the remaining were in functional class II (N=24), III (N=15), and IV (N=1). To differentiate asymptomatic from symptomatic patients, the following variables were analyzed: age at surgery, need for widening the pulmonary ring and trunk, need for a second (2nd OP) or 3rd operation, residual defect of the interventricular septum, residual regurgitation of the pulmonary valve, systolic gradient through the right ventricular outflow tract, right ventricular dilation or hypertrophy (RVH), cardiothoracic index (CTI), right and left ventricular ejection fraction (RVEF/LVEF), and arrhythmias. RESULTS: The univariate analysis showed an association between the presence of symptoms and the 2nd OP (P=0.03), an increase in the CTI (P=0.0001), moderate to severe RVH (P=0.002), and dilation (P=0.0003). In the logistic regression model, the combination of the 2nd OP (P=0.008), the RVH (P=0.002), and the reduction in RVEF (P=0.01) determined the presence of symptoms. CONCLUSION: Despite the surgical treatment, right ventricular remodeling and performance were the major determinants in the late follow-up of tetralogy of Fallot.

An alternative experimental model for training in microsurgery

OBJECTIVE: to describe a new model of training in microsurgery with pig spleen after splenectomy performed by undergraduate students of the Discipline of Operative Technique of the UFPR Medical School. METHODS: after the completion of splenectomy we performed dissection of the vascular pedicle, distal and proximal to the ligation performed for removal of the spleen. After complete dissection of the splenic artery and vein with microscope, clamps were placed and the vessels were cut. We then made the anastomosis of the vessels with 9.0 nylon. RESULT: the microsurgical training with a well-defined routine, qualified supervision and using low cost experimental materials proved to be effective in the practice of initial microvascular surgery. CONCLUSION: the use of pig spleen, which would be discarded after splenectomy, is an excellent model for microsurgical training, since besides having the consistency and sensitivity of a real model, it saves the sacrifice of a new animal model in the initial learning phase of this technique.

Celiac artery in New Zealand rabbit: anatomical study of its origin and arrangement for experimental research and surgical practice

Rabbits have been used as an experimental model in many diseases and for the study of toxicology, pharmacology and surgery in many universities. However, some aspects of their macro anatomy need a more detailed description, especially the abdominal and pelvic arterial vascular system, which has a huge variability in distribution and trajectory. Thirty cadaveric adult New Zealand rabbits, 13 male and 17 female, with an average weight and rostrum-sacral length of 2.5 kg and 40cm, respectively, were used. The thoracic aorta was cannulated and the vascular system was filled with stained latex S-65. The celiac artery and its proximal branches were dissected and lengthened in order to evidence origin and proximal ramifications. The celiac artery emerged between the 12th and 13th thoracic vertebra in 11 (36.7%) rabbits; at the level of the 13th thoracic vertebra in 6 (20%) rabbits; between the 13th thoracic vertebra and the 1st lumbar vertebra in 12 (40%) rabbits; and at the level of the 1st lumbar vertebra in only one (3.3%) rabbit. The mean length of the celiac artery was 0.5cm. The celiac artery first branch was the lienal artery, the second branch was the left gastric artery and the hepatic artery arose from the left gastric artery in all the dissected rabbits. No relation was observed between the celiac artery length and the rostrum-sacral length in rabbits. The number of left gastric and lienal artery branches and the distribution of celiac artery origin are not gender dependent.

Evaluation of a model for induction of periodontal disease in dogs

There are several methods for inducing periodontal disease in animal models, being the bone defect one of the most reported. This study aimed to evaluate this model, through clinical, radiographic, tomographic and histological analyzes, thus providing standardized data for future regenerative works. Twelve dogs were subjected to the induction protocol. In a first surgical procedure, a mucoperiosteal flap was made on the buccal aspect of the right third and fourth premolars and a defect was produced exposing the furcation and mesial and distal roots, with dimensions: 5mm coronoapical, 5mm mesiodistal, and 3mm buccolingual. Periodontal ligament and cementum were curetted and the defect was filled with molding polyester, which was removed after 21 days on new surgical procedure. Clinical and radiographic examinations were performed after the two surgeries and before the collection of parts for dental tomography and histological analysis. All animals showed grade II furcation exposure in both teeth. Clinical attachment level increased after induction. Defect size did not change for coronoapical and buccolingual measurements, while mesiodistal size was significantly higher than at the time of defect production. Radiographic analysis showed decreased radiopacity and discontinuity of lamina dura in every tooth in the furcation area. The horizontal progression of the disease was evident in micro-computed tomography and defect content in the histological analysis. Therefore, it is concluded that this method promotes the induction of periodontal disease in dogs in a standardized way, thus being a good model for future work.

Anti-hyperalgesic effect of electroacupuncture in a model of post-incisional pain in rats

Electroacupuncture has been proposed to be a low cost and practical method that allows effective pain management with minimal collateral effects. In this study we have examined the effect of electroacupuncture against the hyperalgesia developed in a model of post-incisional pain in rats. A 1-cm longitudinal incision was made through the skin and fascia of the plantar region of the animal hind paw. Mechanical hyperalgesia in the incision was evaluated 135 min after the surgery with von Frey filaments. The tension threshold was reduced from 75 g (upper limit of the test) to 1.36 ± 0.36 g (mean ± SEM) in control rats. It is shown that a 15-min period of electroacupuncture applied 120 min after surgery to the Zusanli (ST36) and Sanyinjiao (SP6) points, but not to non-acupoints, produces a significant and long-lasting reduction of the mechanical hyperalgesia induced by the surgical incision of the plantar surface of the ipsilateral hind paw. The tension threshold was reduced from 75 to 27.6 ± 4.2 g in animals soon after the end of electroacupuncture. The mechanical threshold in this group was about 64% less than in control. Electroacupuncture was ineffective in rats treated 10 min earlier with naloxone (1 mg/kg, ip), thus confirming the involvement of opioid mechanisms in the antinociceptive effects of such procedure. The results indicate that post-incisional pain is a useful model for studying the anti-hyperalgesic properties of electroacupuncture in laboratory animals.

An experimental model of mycobacterial infection under corneal flaps

In order to develop a new experimental animal model of infection with Mycobacterium chelonae in keratomileusis, we conducted a double-blind prospective study on 24 adult male New Zealand rabbits. One eye of each rabbit was submitted to automatic lamellar keratotomy with the automatic corneal shaper under general anesthesia. Eyes were immunosuppressed by a single local injection of methyl prednisolone. Twelve animals were inoculated into the keratomileusis interface with 1 µl of 10(6) heat-inactivated bacteria (heat-inactivated inoculum controls) and 12 with 1 µl of 10(6) live bacteria. Trimethoprim drops (0.1%, w/v) were used as prophylaxis for the surgical procedure every 4 h (50 µl, qid). Animals were examined by 2 observers under a slit lamp on the 1st, 3rd, 5th, 7th, 11th, 16th, and 23rd postoperative days. Slit lamp photographs were taken to document clinical signs. Animals were sacrificed when corneal disease was detected and corneal samples were taken for microbiological analysis. Eleven of 12 experimental rabbits developed corneal disease, and M. chelonae could be isolated from nine rabbits. Eleven of the 12 controls receiving a heat-inactivated inoculum did not develop corneal disease. M. chelonae was not isolated from any of the control rabbits receiving a heat-inactivated inoculum, or from the healthy cornea of control rabbits. Corneal infection by M. chelonae was successfully induced in rabbits submitted to keratomileusis. To our knowledge, this is the first animal model of M. chelonae infection following corneal flaps for refractive surgery to be described in the literature and can be used for the analysis of therapeutic responses.

Bioeffects of albumin-encapsulated microbubbles and real-time myocardial contrast echocardiography in an experimental canine model

Myocardial contrast echocardiography has been used for assessing myocardial perfusion. Some concerns regarding its safety still remain, mainly regarding the induction of microvascular alterations. We sought to determine the bioeffects of microbubbles and real-time myocardial contrast echocardiography (RTMCE) in a closed-chest canine model. Eighteen mongrel dogs were randomly assigned to two groups. Nine were submitted to continuous intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) plus continuous imaging using power pulse inversion RTMCE for 180 min, associated with manually deflagrated high-mechanical index impulses. The control group consisted of 3 dogs submitted to continuous imaging using RTMCE without PESDA, 3 dogs received PESDA alone, and 3 dogs were sham-operated. Hemodynamics and cardiac rhythm were monitored continuously. Histological analysis was performed on cardiac and pulmonary tissues. No hemodynamic changes or cardiac arrhythmias were observed in any group. Normal left ventricular ejection fraction and myocardial perfusion were maintained throughout the protocol. Frequency of mild and focal microhemorrhage areas in myocardial and pulmonary tissue was similar in PESDA plus RTMCE and control groups. The percentages of positive microscopical fields in the myocardium were 0.4 and 0.7% (P = NS) in the PESDA plus RTMCE and control groups, respectively, and in the lungs they were 2.1 and 1.1%, respectively (P = NS). In this canine model, myocardial perfusion imaging obtained with PESDA and RTMCE was safe, with no alteration in cardiac rhythm or left ventricular function. Mild and focal myocardial and pulmonary microhemorrhages were observed in both groups, and may be attributed to surgical tissue manipulation.

Comparison of pre- versus post-incision administration of intraplantar indomethacin and MK886 in a rat model of postoperative pain

The amplification of pain long after the initial stimulus may be avoided if the treatment of pain is introduced before its initiation. However, conflicting evidence exists about the efficacy of such preemptive analgesia for the management of postoperative pain. This study compares the efficacy of intraplantar administration of indomethacin (a non-selective inhibitor of cyclooxygenase) and MK886 (an inhibitor of 5-lipoxygenase-activating protein), separately or in combination to produce preemptive analgesia in a model of surgical incisional pain in male Wistar rats. All incised rats (5 to 6 rats per group) had allodynia at 2, 6, and 24 h after surgery as evaluated using von Frey filaments. MK886, but not indomethacin (50 to 200 µg/paw), reduced the allodynia when injected either 1 h before or 1 h after surgery. The effect of preoperative MK886 (160 µg/paw) against incisional allodynia had a magnitude apparently similar to that produced by postoperative MK886. Pre-, but not postoperative MK886 (80 µg/paw) reduced the allodynia but the effect was seen only at 6 h after surgery. In contrast, MK886 (40 µg/paw) intensified the allodynia observed 2 h after the incision either injected before or after surgery. MK886 or indomethacin alone did not provide preemptive analgesia in the model of incisional pain. In contrast, the combination of MK886 with indomethacin reduced the allodynia more effectively when used before than after surgery, thus fulfilling the criteria for preemptive analgesia. In conclusion, preoperative inhibition of the local generation of both prostaglandins and leukotrienes by surgical incision may be an alternative to provide preemptive analgesia.

An improved experimental model for peripheral neuropathy in rats

A modification of the Bennett and Xie chronic constriction injury model of peripheral painful neuropathy was developed in rats. Under tribromoethanol anesthesia, a single ligature with 100% cotton glace thread was placed around the right sciatic nerve proximal to its trifurcation. The change in the hind paw reflex threshold after mechanical stimulation observed with this modified model was compared to the change in threshold observed in rats subjected to the Bennett and Xie or the Kim and Chung spinal ligation models. The mechanical threshold was measured with an automated electronic von Frey apparatus 0, 2, 7, and 14 days after surgery, and this threshold was compared to that measured in sham rats. All injury models produced significant hyperalgesia in the operated hind limb. The modified model produced mean ± SD thresholds in g (19.98 ± 3.08, 14.98 ± 1.86, and 13.80 ± 1.00 at 2, 7, and 14 days after surgery, respectively) similar to those obtained with the spinal ligation model (20.03 ± 1.99, 13.46 ± 2.55, and 12.46 ± 2.38 at 2, 7, and 14 days after surgery, respectively), but less variable when compared to the Bennett and Xie model (21.20 ± 8.06, 18.61 ± 7.69, and 18.76 ± 6.46 at 2, 7, and 14 days after surgery, respectively). The modified method required less surgical skill than the spinal nerve ligation model.

Early neonatal echocardiographic findings in an experimental rabbit model of congenital diaphragmatic hernia

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (P<0.005), left lung weight (P<0.005), and lung-to-body ratio (P<0.005). Echocardiography revealed a smaller left-to-right ventricle ratio (LV/RV, P<0.005) and larger diastolic right ventricle size (DRVS, P<0.007). Histologic analysis revealed a larger number of myocytes undergoing mitotic division (186 vs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH.

A network society communicative model for optimizing the Refugee Status Determination (RSD) procedures

This article recommends a new way to improve Refugee Status Determination (RSD) procedures by proposing a network society communicative model based on active involvement and dialogue among all implementing partners. This model, named after proposals from Castells, Habermas, Apel, Chimni, and Betts, would be mediated by the United Nations High Commissioner for Refugees (UNHCR), whose role would be modeled after that of the International Committee of the Red Cross (ICRC) practice.

The international implications of the Chinese model of development in the Global South: Asian Consensus as a network power

This paper analyzes People's Republic of China (PRC) economic and political ascendance in the 21st century focusing on the evolution of the sui generis economic development model and its significances of the evolution of relationship between China and the developing countries in the peripheral "Global South." The objective of this article is to analyze the relationship between China and the Global South (Africa and South America) in the 21st century, characterized as a new Center-periphery global network power based on trade and investment that we call as "Asian Consensus."

Particulate bioglass in the regeneration of alveolar bone in dogs: clinical, surgical and radiographic evaluations

Bone loss, either by trauma or other diseases, generates an increasing need for substitutes of this tissue. This study evaluated Bioglass as a bone substitute in the regeneration of the alveolar bone in mandibles of dogs by clinical, surgical and radiological analysis. Twenty-eight adult dogs were randomly separated into two equal groups. In each animal, a bone defect was created on the vestibular surface of the alveolar bone between the roots of the fourth right premolar tooth. In the treated group, the defect was immediately filled with bioglass, while in the control, it remained unfilled. Clinical evaluations were performed daily for a week, as well as x-rays immediately after surgery and at 8, 14, 21, 42, 60, 90 and 120 days post-operative. Most animals in both groups showed no signs of inflammation and wound healing was similar. Radiographic examination revealed a gradual increase of radiopacity in the region of the defect in the control group. In the treated group, initial radiopacity was higher than that of adjacent bone, decreasing until 21 days after surgery. Then it gradually increased until 120 days after surgery, when the defect became undetectable. The results showed that Bioglass integrates into bone tissue, is biocompatible and reduced the period for complete bone regeneration.