Does sequential balloon expulsion test improve the screening of defecation disorders?

BACKGROUND: A defecation disorder (DD) is a difficulty in evacuation documented by physiological exams. However, this physiological evaluation can be cumbersome, inaccessible and costly. Three "low-cost" tools to evaluate DD-a clinical DD score, the balloon expulsion test (BET) and a digital rectal examination (DRE) score were evaluated as separate or combined tests for DD screening. METHODS: This prospective study occurred between January 2015 and March 2019 in the Gastroenterology Department of a tertiary hospital. Besides the gold standard physiological tests, constipated patients answered the clinical DD score and were evaluated by DRE and BET [standard and variable volume (VV)]. RESULTS: From 98 constipated patients, 35 (38.9%) were diagnosed with DD according to Rome IV criteria, mainly female (n = 30, 86%) with a median age of 60 years old. The clinical DD score revealed an AUC of 0.417 (SE = 0.07, p = 0.191). The DRE score displayed an AUC of 0.56 (SE = 0.063, p = 0.301). The standard BET displayed a sensitivity of 86%, specificity of 58%, positive predictive value (PPV) of 57% and negative predictive value (NPV) of 86%. The sequential VVBET followed by standard BET improved the BET performance regarding the evaluation of DD, with a sensitivity of 86%, specificity of 67%, PPV of 63% and NPV of 87%. The sequential BET had an OR 8.942, p > 0.001, CI 3.18-25.14, revealing to be the most significant predictor for DD screening. CONCLUSION: The sequential BET is a low cost, well-performing DD screening tool, appropriate to the Primary Care Setting.

Transanal total mesorectal excision: a pure NOTES approach for selected patients.

BACKGROUND: The concept of natural orifice transluminal endoscopic surgery (NOTES) has stimulated the development of various "incisionless" procedures. One of the most popular is the transanal approach for rectal lesions. The aims of this study were to report how we standardized NOTES technique for transanal mesorectal excision without abdominal assistance, discuss the difficulties and surgical outcomes of this technique and report its feasibility in a small group of selected patients. METHODS: Three consecutive female patients underwent transanal NOTES rectal resection without transabdominal laparoscopic assistance for rectal lesions. Functional results were assessed with the Fecal Incontinence Quality of Life scale and the Wexner score. RESULTS: The technical steps are described in details and complemented with a video. All procedures were completed without transabdominal laparoscopic help. The mesorectal plane was entirely dissected without any disruption, and distal and circumferential margins were tumor-free. No major complications were observed. Functional results show a significant impairment after surgery with improvement at 6 months to levels near those of the preoperative period. CONCLUSIONS: The performance and publication of NOTES procedures are subject to much discussion. Despite the small number of patients, this procedure appears feasible and can be accomplished maintaining fecal continence and respecting oncologic principles.

CycleGAN-Based Image to Image Translation for Realistic Surgical Training Phantoms.

Training in surgery is essential for surgeons to develop skill and dexterity. Physical training phantoms provide excellent haptic feedback and tissue properties for stitching and operating with authentic instruments and are easily available. However, they lack realistic traits and fail to reflect the complex environment of a surgical scene. Generative Adversarial Networks can be used for image-to-image translation, addressing the lack of realism in physical phantoms, by mapping patterns from the intraoperative domain onto the video stream captured during training with these surgical simulators. This work aims to achieve a successful I2I translation, from intra-operatory mitral valve surgery images onto a surgical simulator, using the CycleGAN model. Different experiments are performed - comparing the Mean Square Error Loss with the Binary Cross Entropy Loss; validating the Fréchet Inception Distance as a training and image quality metric; and studying the impact of input variability on the model performance. Differences between MSE and BCE are modest, with MSE being marginally more robust. The FID score proves to be very useful in identifying the best training epochs for the CycleGAN I2I translation architecture. Carefully selecting the input images can have a great impact in the end results. Using less style variability and input images with good feature details and clearly defined characteristics enables the network to achieve better results.Clinical Relevance- This work further contributes for the domain of realistic surgical training, successfully generating fake intra operatory images from a surgical simulator of the cardiac mitral valve.

Transesophageal pulmonary lobectomy with single transthoracic port assistance: study with survival assessment in a porcine model.

BACKGROUND AND STUDY AIMS: Thoracoscopic pulmonary lobectomy is being performed in an increasing number of patients. The aims of the current study were to assess natural orifice transluminal endoscopic surgery (NOTES) as an alternative to transthoracic endoscopic surgery, and to test the feasibility of peroral transesophageal right upper pulmonary lobectomy with the assistance of a single transthoracic trocar. METHODS: In 10 acute and 4 survival pigs, right upper pulmonary lobectomy was performed using a forward-viewing double-channel gastroscope and an operative thoracoscope with a 5-mm working channel inserted through a single transthoracic 12-mm) port. Time, safety, and feasibility of the following steps were recorded in all animals: esophagotomy, hilar dissection, individual ligation of the hilum elements, pulmonary lobectomy, and specimen retrieval. In the survival experiments, esophagotomy was closed using a reticulated laparoscopy suture device and an esophageal stent was placed. These animals were kept alive and monitored for 2 weeks. RESULTS: Esophagotomy was performed safely in all animals (mean procedure duration 5.4 ± 1.7 minutes). Dissection of the right upper lobe hilum elements (bronchus, arteries, and veins) was carried out without adverse events. Individual ligation of the hilum elements was performed in all but two cases (time for dissection and ligation 44.2 ± 14.8 minutes). Lobectomy and specimen retrieval were completed in all animals (9.5 ± 3.1 minutes). Esophagotomy closure and stent placement were carried out in 20.0 ± 2.8 minutes in the survival animals. These animals fed normally and gained weight postoperatively without signs of disease. Endoscopic examination before necropsy revealed a pseudo-diverticulum in one animal, and wound dehiscence with confined collection/recess in the remaining animals. CONCLUSIONS: Transesophageal right upper pulmonary lobectomy using single transthoracic trocar assistance is feasible and may represent a step towards scar-free pulmonary lobectomy.

Peroral esophageal segmentectomy and anastomosis with single transthoracic trocar: a step forward in thoracic NOTES.

BACKGROUND AND STUDY AIMS: A transesophageal natural orifice transluminal endoscopic surgery (NOTES) approach has been proposed for thoracic and mediastinal access. Similarly to transgastric surgery, serious limitations remain related to creating an esophagotomy and its safe closure. A hybrid approach in thoracic NOTES could work as an intermediate step before pure transesophageal NOTES. We assessed the benefit of hybrid thoracic NOTES for peroral segmental esophagectomy and subsequent complete esophageal anastomosis with a single transthoracic port. METHODS: Two protocols were used to attempt esophago-esophageal anastomosis: ex vivo using a phantom model (n = 5), and in vivo after esophageal mobilization, and segmental esophagectomy achieved using either a gastroscope (flexible) (n = 5) or thoracoscope (rigid) instruments (n = 5). A forward-viewing double-channel endoscope and a transthoracic operative thoracoscope with a working channel were coordinated in order to create a complete single-layer, end-to-end esophageal anastomosis ex vivo as well as in vivo. Feasibility and anastomosis quality were evaluated by inside and outside assessment of: patency, the incorporation of mucosa in all stitches, and a leak test. RESULTS: Anastomosis was achieved in all ex vivo experiments and thoracoscopically-led in vivo procedures. All anastomoses were patent, allowing distal passage of the endoscope, with mucosa incorporation. In in vivo experiments, a leak was detected in three animals and corrected with additional stitching. CONCLUSIONS: Peroral esophageal anastomosis with a single transthoracic trocar is feasible, which may represent a step forward in thoracic NOTES.

Transvesical peritoneoscopy with rigid scope: feasibility study in human male cadaver.

BACKGROUND: Transvesical port refers to the method of accessing the abdominal cavity through a natural orifice (i.e., urethra) under endoscopic visualization. Since its introduction in 2006, various reports have been published describing different surgical interventions using a rigid ureteroscope in a porcine model. The aim of this study was to test the access and feasibility of peritoneoscopy by using a rigid ureteroscope in a human male cadaver. METHODS: Two adult male cadavers were used to perform the procedures. A rigid ureteroscope was used for the creation of transvesical access into the peritoneal cavity. Peritoneoscopy, liver biopsy, and identification and manipulation of the ileocecal appendix were performed. RESULTS: Transvesical access into the peritoneal cavity was quickly established. The rigid ureteroscope easily allowed visualization of the abdominal cavity with good image quality. Liver biopsy and manipulation of ileocecal appendix were carried out without difficulties. CONCLUSIONS: Peritoneoscopy, liver biopsy, and ileocecal appendix manipulation using a rigid ureteroscope through a transvesical port is feasible in a cadaver model. The development of a specific rigid scope for the transvesical port might herald a promising future for this NOTES access.

Congenital diaphragmatic hernia - the neonatal period (part I).

AIM: The aim of the study was to review our experience in the management of newborns with congenital diaphragmatic hernia (CDH). METHODS: A retrospective study including all infants with CDH at the Hospital de São João, a center that does not provide ECMO support, for the period from 1997 to 2006. Since 2003, a new treatment protocol has been used. RESULTS: There were 61 newborns (30 male/31 female) with a birth weight of 2800 g (880 - 3770), and a gestational age of 38 weeks (28 - 41); 46 (75 %) were inborn and 42 (69 %) had a prenatal diagnosis of CDH. There were 2 (3 %) chromosomal anomalies, 3 (5 %) with other congenital anomalies and 1 (2 %) with nonimmune hydrops fetalis. The diaphragmatic defect was left sided in 55 (90 %) cases. Corrective surgery was performed in 43 (70 %) patients. New therapies were used: HFOV 13 % (n = 8); inhaled nitric oxide 13 % (n = 8); and sildenafil 7 % (n = 4). We found that systemic arterial hypotension (p = 0.001), the severity of pulmonary hypertension (p = 0.001), prenatal diagnosis (p = 0.006), birth weight (p = 0.022), female gender (p = 0.029), inborn birth (p = 0.030), arterial pH < 7.35 at admission (p = 0.030), right-sided defect (p = 0.033) and pneumothorax (p = 0.033) to be predictive of mortality. The overall survival rate was 43 % (n = 26), and since 2003 this rate has improved to 61 % for term neonates without other congenital or chromosomal anomalies. CONCLUSIONS: Our survival rate for infants with CDH has improved over the last ten years, and this improvement is associated with the use of new therapies such as HFOV, inhaled nitric oxide and sildenafil.

Congenital Diaphragmatic Hernia. The Post-neonatal period. Part II.

AIM: The aim of the study was to review our experience in the management of newborns with congenital diaphragmatic hernia (CDH). METHODS: A retrospective study including all infants with CDH at the Hospital de São João, a center that does not provide ECMO support, for the period from 1997 to 2006. Since 2003, a new treatment protocol has been used. RESULTS: There were 61 newborns (30 male/31 female) with a birth weight of 2800 g (880 - 3770), and a gestational age of 38 weeks (28 - 41); 46 (75 %) were inborn and 42 (69 %) had a prenatal diagnosis of CDH. There were 2 (3 %) chromosomal anomalies, 3 (5 %) with other congenital anomalies and 1 (2 %) with nonimmune hydrops fetalis. The diaphragmatic defect was left sided in 55 (90 %) cases. Corrective surgery was performed in 43 (70 %) patients. New therapies were used: HFOV 13 % (n = 8); inhaled nitric oxide 13 % (n = 8); and sildenafil 7 % (n = 4). We found that systemic arterial hypotension (p = 0.001), the severity of pulmonary hypertension (p = 0.001), prenatal diagnosis (p = 0.006), birth weight (p = 0.022), female gender (p = 0.029), inborn birth (p = 0.030), arterial pH < 7.35 at admission (p = 0.030), right-sided defect (p = 0.033) and pneumothorax (p = 0.033) to be predictive of mortality. The overall survival rate was 43 % (n = 26), and since 2003 this rate has improved to 61 % for term neonates without other congenital or chromosomal anomalies. CONCLUSIONS: Our survival rate for infants with CDH has improved over the last ten years, and this improvement is associated with the use of new therapies such as HFOV, inhaled nitric oxide and sildenafil.

Effects of TNF-alpha blockade in monocrotaline-induced pulmonary hypertension.

INTRODUCTION: TNF-alpha blockade in ischemic heart failure is still the subject of debate since clinical trials show conflicting results. However, its benefit in heart failure secondary to pulmonary hypertension has yet to be determined. It has been reported that transgenic rats overexpressing TNF-alpha develop pulmonary hypertension. The aim of this study was to assess the morphologic and hemodynamic effects of administration of an anti-TNF-alpha monoclonal antibody (etanercept) in rats with monocrotaline (MCT)-induced pulmonary hypertension. METHODS: Adult Wistar rats were injected with MCT (60 mg/Kg sc), or vehicle only (day 0). Beginning one day later, the animals were randomly treated with etanercept (ETC, 0.03 mg/Kg sc, three times a week) or with a similar volume of vehicle. The study thus had four groups: Ctrl (n = 6), Ctrl + ETC (n = 6), MCT (n = 6) and MCT + ETC (n = 6). On days 22-23, the rats were instrumented to record right ventricular systolic and end-diastolic pressures, dP/dtmax and tau. At the end of each experiment the heart and lungs were weighed. RESULTS AND CONCLUSIONS: Chronic administration of etanercept induced only a slight increase in relaxation velocity, with no effect on other hemodynamic parameters, including pulmonary hypertension, and no reduction in right ventricular hypertrophy. These results suggest that etanercept does not lead to a significant improvement in heart failure secondary to pulmonary hypertension.

Differential right and left ventricular diastolic tolerance to acute afterload and NCX gene expression in Wistar rats.

This study evaluated right ventricular (RV) and left ventricular (LV) diastolic tolerance to afterload and SERCA2a, phospholamban and sodium-calcium exchanger (NCX) gene expression in Wistar rats. Time constant tau and end diastolic pressure-dimension relation (EDPDR) were analyzed in response to progressive RV or LV afterload elevations, induced by beat-to-beat pulmonary trunk or aortic root constrictions, respectively. Afterload elevations decreased LV- tau, but increased RV-tau. Whereas LV- tau analyzed the major course of pressure fall, RV- tau only assessed the last fourth. Furthermore, RV afterload elevations progressively upward shifted RV EDPDR, whilst LV afterload elevations did not change LV-EDPDR. SERCA2a and phospholamban mRNA were similar in both ventricles. NCX-mRNA was almost 50 % lower in RV than in LV. Left ventricular afterload elevations, therefore, accelerated the pressure fall and did not induce diastolic dysfunction, indicating high LV diastolic tolerance to afterload. On the contrary, RV afterload elevations decelerated the late RV pressure fall and induced diastolic dysfunction, indicating small RV diastolic tolerance to afterload. These results support previous findings relating NCX with late Ca(2+) reuptake, late relaxation and diastolic dysfunction.

Minimally invasive repair of Morgagni hernia - A multicenter case series.

Children may benefit from minimally invasive surgery (MIS) in the correction of Morgagni hernia (MH). The present study aims to evaluate the outcome of MIS through a multicenter study. National institutions that use MIS in the treatment of MH were included. Demographic, clinical and operative data were analyzed. Thirteen patients with MH (6 males) were operated using similar MIS technique (percutaneous stitches) at a mean age of 22.2±18.3 months. Six patients had chromosomopathies (46%), five with Down syndrome (39%). Respiratory complaints were the most common presentation (54%). Surgery lasted 95±23min. In none of the patients was the hernia sac removed; prosthesis was never used. In the immediate post-operative period, 4 patients (36%) were admitted to intensive care unit (all with Down syndrome); all patients started enteral feeds within the first 24h. With a mean follow-up of 56±16.6 months, there were two recurrences (18%) at the same institution, one of which was repaired with an absorbable suture; both with Down syndrome. The application of MIS in the MH repair is effective even in the presence of comorbidities such as Down syndrome; the latter influences the immediate postoperative recovery and possibly the recurrence rate. Removal of hernia sac does not seem necessary. Non-absorbable sutures may be more appropriate.

Afterload induced changes in myocardial relaxation: a mechanism for diastolic dysfunction.

BACKGROUND: Diastolic left ventricular (LV) dysfunction manifests as an upward shift of the diastolic pressure-volume relation. One of the possible causes of diastolic LV dysfunction is incomplete myocardial relaxation. It is well known that high afterload slows myocardial relaxation. This contribution investigated to what extent afterload elevation could also affect LV filling pressures including end-diastolic LV pressure (LVP). METHODS: Selective, beat-to-beat elevations of afterload were induced in anaesthetised open-chest rabbits (n = 9) by abrupt narrowing of the ascending aorta during the diastole of the preceding heartbeat. This was performed with physiological heart rate and blood pressure. RESULTS: These interventions increased systolic LVP from 90 +/- 3 mm Hg at baseline to 103 +/- 4, 123 +/- 5, 139 +/- 5 and 154 +/- 6 mm Hg. The last intervention was a total aortic occlusion inducing a first beat isovolumetric contraction. Smaller afterload elevations decreased tau (accelerated LVP fall) and did not elevate diastolic pressure-internal diameter relation (P-ID). Larger afterload elevations increased tau (decelerated LVP fall), induced an upward shift of the diastolic P-ID and increased end-diastolic LVP. Effects of afterload on end-diastolic LVP were correlated with effects on tau (r = 0.89; P < 0.01). Incomplete relaxation or load-dependent residual active state appeared to be the mechanism for this diastolic dysfunction. Similar findings were made retrospectively in dogs instrumented with circumferential segment length gauges (n = 16). CONCLUSIONS: Diastolic LV dysfunction was induced by elevated afterload in healthy hearts of rabbits and dogs. If this mechanism could be shown to be operative in the failing heart, reversal of diastolic dysfunction should contribute to the beneficial effects of vasodilating and inotropic therapy on pulmonary congestion.

Scarless laparoscopic repair of epigastric hernia in children.

BACKGROUND: Despite the small size of the incision, the scar left by open repair of epigastric hernia in children is unaesthetic. Few laparoscopic approaches to epigastric hernia repair have been previously proposed, but none has gain wide acceptance from pediatric surgeons. In this study, we present our experience with a scarless laparoscopic approach using a percutaneous suturing technique for epigastric hernia repair in children. METHODS: Ten consecutive patients presenting with epigastric hernia 15 mm or further from the umbilicus were submitted to laparoscopic hernia repair. A 5-mm 30º-angle laparoscope is introduced through a umbilical trocar and a 3-mm laparoscopic dissector is introduced through a stab incision in the right flank. After opening and dissecting the parietal peritoneum, the fascial defect is identified and closed using 2-0 polyglactin thread through a percutaneous suturing technique. Intraoperative and postoperative clinical data were collected. RESULTS: All patients were successfully submitted to laparoscopic epigastric hernia repair. Median age at surgery was 79 months old and the median distance from the umbilicus to the epigastric defect was 4 cm. Operative time ranged from 35 to 75 min. Every hernia was successfully closed without any incidents. Follow-up period ranges from 2 to 12 months. No postoperative complications or recurrence was registered. No scar was visible in these patients. CONCLUSION: This scarless laparoscopic technique for epigastric hernia repair is safe and reliable. We believe this technique might become gold standard of care in the near future.

Pattern of right ventricular pressure fall and its modulation by afterload.

Pattern of right ventricular pressure (RVP) fall and its afterload dependence were examined by analyzing ventricular pressure curves and corresponding pressure dP/dt phase planes obtained in both ventricles in the rat heart in situ. Time and value of dP/dt(min), and the time constant tau were measured at baseline and during variable RV afterload elevations, induced by beat-to-beat pulmonary trunk constrictions. RVP and left ventricular pressure (LVP) decays were divided into initial accelerative and subsequent decelerative phases separated by corresponding dP/dt(min). At baseline, LVP fall was decelerative during 4/5 of its course, whereas only 1/3 of RVP decay occurred in a decelerative fashion. During RV afterload elevations, the absolute value of RV-dP/dt(min) and RV-tau increased, whilst time to RV dP/dt(min) decreased. Concomitantly, the proportion of RVP decay following a decelerative course increased, so that in highly RV afterloaded heartbeats RVP fall became more similar to LVP fall. In conclusion, RVP and LVP decline have distinct patterns, their major portion being decelerative in the LV and accelerative in the RV. In the RV, dP/dt(min), tau and the proportional contribution of accelerative and decelerative phases for ventricular pressure fall are afterload-dependent. Consequently, tau evaluates a relatively much shorter segment of RVP than LVP fall.

Neonatal perforation of a Y-shaped sigmoid duplication.

Tubular colonic duplications are exceedingly rare; the "Y"-shaped forms are exceptional. In the absence of associated low vertebral or urogenital malformations (often fistulas), the tubular colonic malformations frequently stay hidden for several years until a complication develops. The authors report a case of a spontaneous perforation of a Y-shaped tubular colonic duplication during the neonatal period.

Heart-related indices in experimental diaphragmatic hernia.

BACKGROUND: Heart-related indices have been suggested as useful tools to evaluate left ventricular (LV) hypoplasia, which might predict the outcome of fetuses and infants with congenital diaphragmatic hernia (CDH). The current study analyzed the behavior of such indices in the nitrofen-induced CDH rat model. METHODS: Dated pregnant Wistar rats received at day 9.5 of gestation either a dose of 100 mg of nitrofen or just the vehicle. Body, lung, and heart weights were measured in 12 newborn rats not exposed to nitrofen (Ctrl group) and 68 animals exposed to nitrofen: 30 without CDH (non-CDH group) and 38 with left CDH (CDH group). Each heart was fragmented in 7-microm thick sections. Only hearts with no evidence of cardiac morphologic defects (CMD) were studied further to estimate right and left ventricular cavity volumes, septal, right, and left ventricular free wall masses. These parameters allowed the calculation of the cardio-ventricular (CVindex) and LV mass indices. The aorta-to-pulmonary artery ratio also was calculated. RESULTS: Excluding fetuses with CMD, the heart-to-body weight ratio was reduced significantly in animals exposed to nitrofen, whereas no significant differences were observed between non-CDH versus CDH groups. Although the left and right ventricular cavity volumes were both reduced significantly in nitrofen-treated rats, they were not changed significantly by the existence of CDH, and the calculated CVindex was similar in the 3 groups. Estimated septal and LV masses were reduced markedly in the nitrofen-treated animals and further reduced by the presence of CDH. However, when LV mass was normalized (LV mass index) the difference became restricted to the animals exposed to nitrofen but was not influenced by the presence of CDH. Finally, the aorta-to-pulmonary artery ratio was similar in all studied groups. CONCLUSIONS: The results of the current study suggest that, although nitrofen had been responsible by global heart hypoplasia, the presence of CDH was not associated with significant underdevelopment of the heart or of the LV in rat fetuses without CMD. Based on these results, we think that the evidence for prenatal counseling based on heart-related indices should be critically reconsidered.

A new fetal rat model of gastroschisis: development and early characterization.

BACKGROUND/PURPOSE: The perinatal management and pathophysiology of gastroschisis remain controversial. Large animal experimental models of gastroschisis are inherently limited by expense and length of gestation, making multiple studies and statistical analysis difficult. To address these limitations the authors have developed a model of gastroschisis in the fetal rat. METHODS: Twenty-one time-dated pregnant rats underwent laparotomy at 18 (1/2) day's gestational age. The exposed uterus was bathed in ritodrine for tocolysis. The right posterior leg was exteriorized through a hysterotomy, and under a dissecting microscope (16x) the fetal small bowel was exteriorized through a small incision performed on the right lower abdominal quadrant. The amniotic fluid was restored with saline solution and the hysterotomy closed with a purse-string suture. Control fetuses underwent hysterotomy and leg manipulation only. The surgical time was uniformly less than 60 minutes. Fetuses were harvested by cesarean section at 21 (1/2) days' gestational age. Fetal intestine was assessed by microscopic examination, and fetal weight, intestinal length, and intestinal weight per unit length were evaluated. RESULTS: There was a significant surgical and anesthetic learning curve, which is not included in this report. After this, the authors achieved a maternal survival of 100% (n = 21). We created gastroschisis in 64 fetuses (58 survivors, 90.6%), and 33 fetuses were only manipulated (30 survivors, 90.9%). The number of induced gastroschisis per pregnant rat varied between 2 and 5 with median of 3. On gross examination, eviscerated intestine appeared dilated, edematous, and covered by peel when compared with control intestine. Fetuses with gastroschisis had significantly reduced body weight (4.1+/-0.5 v 5.6 g +/- 0.5 g) and intestinal length (102+/-19 v 210+/-17 mm) relative to controls, whereas the intestinal weight per unit length (1.75+/-0.29 v 0.71 +/- 0.1 mg/mm) was markedly increased (P<.001). CONCLUSIONS: The pathophysiology observed in this experimental model appears to resemble human gastroschisis. In comparison with large animal models, the rat model offers the advantages of low expense, short gestation, littermate controls, and high maternal and fetal survival rates. In addition, there are specific probes and reagents available for application of molecular methodology to clarify the mechanisms responsible for the intestinal damage. This model appears appropriate for future experimental studies on gastroschisis.

Neonatal splenic necrosis not related to wandering spleen.

Splenic necrosis is extremely rare in neonates, the cases recorded so far being secondary to torsion of wandering organs. A newborn with an abdominal mass who underwent exchange transfusions through an umbilical catheter is presented here. Comprehensive investigation led to the suspicion of enteric duplication, but a splenic necrosis with no features of wandering spleen was found at laparotomy. The pathogenesis and preoperative diagnostic work-up of splenic necrosis are emphasised.

[Diastolic function modulation by load. Physiological basis and clinical implications]. / Modulação da função diastólica pela carga. Bases fisiológicas e implicações Clínicas.

INTRODUCTION AND OBJECTIVES: Diastolic heart failure has emerged over the last decade as a separate clinical entity, but its pathophysiology is still largely unknown. Left ventricular (LV) relaxation is considered an important determinant of early, but not late, LV filling. We recently showed that a substantial afterload elevation induces a marked slowing of relaxation. In this study we investigated the repercussion of such slowing on late LV filling. METHODS: The study was carried out on 7 open-chest, anaesthetised, New Zealand white rabbits, fully instrumented to evaluate cardiac function. The load was manipulated by transient occlusions of the ascending aorta and/or of the inferior vena cava. RESULTS: We observed that the afterload elevations had a biphasic effect on the relaxation rate and diastolic pressure-dimension (P-D) relation: small elevations accelerated relaxation and did not affect the diastolic P-D relation, while greater elevations progressively decreased the relaxation rate and induced a divergent upward shift of the diastolic P-D. The magnitude of this upward shift was related to the relaxation rate and the time available for the ventricle to relax. CONCLUSIONS AND IMPLICATIONS: Small to moderate afterload elevations are easily compensated by the normal ventricle, while greater elevations induce diastolic dysfunction even in normal hearts, which leads us to the concept of afterload reserve. This concept helps explain why diastolic dysfunction and pulmonary congestion, present in heart failure, may be reverted by decreasing the load (e.g. vasodilators and diuretics).

[Interaction between load and beta-adrenergic stimulation in the modulation of diastolic function]. / Interacção da carga com a estimulação beta-adrenérgica na modulação da função diastólica.

INTRODUCTION AND OBJECTIVES: Excessive afterload induces an upward shift of the diastolic pressure-volume relation. This diastolic dysfunction was attributed to the concomitant slowing of relaxation. The present study investigated to what extent beta-adrenergic stimulation could influence this effect. METHODS: Beat-to-beat afterload elevations were induced in anaesthetised open-chest rabbits (n = 7) by narrowing the ascending aorta, to increase peak left ventricular pressure (LVPmax) from control up to isovolumetric. Afterload elevations were performed at baseline and during infusion of isoproterenol (0.15 mg/kg/min). RESULTS: At baseline, LVPmax increased from 84 +/- 7 in the control beat to 154 +/- 10 mmHg in the isovolumetric beat, while during isoproterenol it increased from 88 +/- 4 to 184 +/- 11 mmHg (p < 0.01). After an isovolumetric beat, diastolic dysfunction was 7.9 +/- 1.5 mmHg at baseline and 2.6 +/- 0.5 mmHg during isoproterenol (p < 0.01). At all afterload levels, isoproterenol accelerated LVP fall (decreased the time constant tau), decreased the predicted time to completion of relaxation but did not influence the time available for the ventricle to relax. CONCLUSIONS AND IMPLICATIONS: Afterload induced diastolic dysfunction was attenuated by beta-adrenergic stimulation. These results, along with the inotropic and lusitropic effects of isoproterenol, may contribute to the acute improvement of cardiac function induced by beta-adrenergic stimulation. It may also help to explain the response to physical exercise and the pathophysiology of diastolic dysfunction in heart failure.