Lymphatic drainage of heart and lungs: comparison between pig and man

In its anatomy and physiology the pig is comparable with humans and its organs can be considered for xenotransplantation. We have studied the lymphatic drainage of the heart and lungs in 15 pigs. A coloured mass was injected into the myocardium and/or beneath the visceral pleura. The first nodes coloured were directly injected again. No lymph node was observed inside the heart and lungs. The first lymph nodes coloured were the peritracheobronchial nodes. There was no node in front of the thoracic trachea (Barety's compartment in man). Left suprabronchial nodes were connected with the thoracic duct in the mediastinum. The lymphatics of the heart and lungs in the pig are similar to those of human. Phylogenesis explains "skipping" metastases and the significance of N1 disease in lung cancer, as well as chylothorax occurring after heart and lung surgery.

Continuous venovenous hemodialysis in a neonate model: a two-pump system

OBJECTIVE

To evaluate the efficiency and tolerance of venovenous hemofiltration, hemodiafiltration, and hemodialysis with a two-pump system in a neonatal animal model of acute renal failure.

DESIGN

Prospective trial.

SETTING

Animal laboratory at a large university-affiliated medical center.

SUBJECTS

New Zealand white rabbits, weighing 3325 +/- 380 g.

INTERVENTIONS

Venovenous hemofiltration, hemodiafiltration, and hemodialysis were performed in anesthetized rabbits with previous bilateral ureteral ligation.

MEASUREMENTS AND MAIN RESULTS

At a blood flow rate of 19 +/- 0.5 mL/min, we determined hematocrit, urea, creatinine, and electrolyte values in blood, at the inlet and outlet of the hemofilter, and in ultrafiltrate at the start and after 15, 30, 60, 90, 120, and 180 mins of hemofiltration (ultrafiltrate flow rate of 1.9 +/- 0.2 mL/min), hemodiafiltration (dialysate plus ultrafiltrate flow rate of 16.9 +/- 0.8 mL/min), and hemodialysis (dialysate flow rate of 15.7 +/- 1.1 mL/min). Arterial blood pressure, heart rate, and body temperature were monitored during the procedures. Urea and creatinine instantaneous clearances were higher with hemodiafiltration (8.0 +/- 0.7 and 6.2 +/- 0.7, respectively, n = 29) and hemodialysis (6.8 +/- 1.1 and 4.8 +/- 0.9, respectively, n = 31) than with hemofiltration (1.8 +/- 0.6 and 1.9 +/- 0.4, respectively, n = 16). Initial and final weights, temperatures, and hematocrit, sodium, and protein blood concentrations of each 180-min procedure were similar.

CONCLUSIONS

Hemodiafiltration had a higher urea removal rate than hemodialysis but the management of hemodiafiltration was more cumbersome and time consuming in the absence of a flow equalizer device. As a result, we recommend continuous venovenous hemodialysis as the therapy of choice.

Route of nutrient delivery affects insulin sensitivity and liver glucose transporter expression in rat

To optimize artificial nutrition (AN) techniques for patients suffering from malnutrition or reduced intestinal absorption, utilization of energy fuels, especially glucose, requires better understanding. Because the liver plays a key role in glucose homeostasis, the aim of this study was to assess the effects of continuous intragastric and intravenous nutrition on insulin secretion and several markers of liver glucose metabolism, especially glucose transporter GLUT-2. Wistar male rats underwent catheterization of either stomach (intragastric) or vena cava (intravenous) and received 24 h/day the same all-in-one formula over 7 to 14 days. The metabolic parameters from intragastrically fed rats did not differ significantly from those from orally fed control rats. Intravenous nutrition induced insulin resistance (marked hyperinsulinemia and/or mild hyperglycemia) and reduced liver GLUT-2 protein and mRNA levels. The decrease in liver GLUT-2 gene expression might be mediated either by an inhibitory role of hyperinsulinemia or by the decrease in gut or portal factors. These results suggest that the route of nutrient delivery influences their utilization by the liver.

Ureteral and bladder lesions after ballistic, ultrasonic, electrohydraulic, or laser lithotripsy

Four techniques of intracorporeal lithotripsy are now available: ballistic, ultrasonic, electrohydraulic, and laser. Their therapeutic efficacies have generally been evaluated and compared, but very few data have been available on their relative risks of iatrogenic trauma to the urothelial wall. We conducted a comparative analysis of this risk by testing the pig ureteral and bladder wall with the EMS Lithoclast, Olympus ultrasonic lithotripter, Walz Lithotron EL 23, and Versa Pulse Ho:YAG Coherent Laser. We measured the number of shockwaves or the energy required to perforate the ureter and bladder by delivering shocks perpendicular to the walls. Ureteral perforation was impossible with the 1.0-mm Lithoclast transducer and the 1.5-mm ultrasound transducer. Perforation was induced after 250 shocks with the 0.8-mm Lithoclast transducer, after 110 shocks with the 3F electrohydraulic electrode, and after 0.02 kJ with the laser. Bladder perforation was impossible with the 2.0-mm Lithoclast device and the 3.4-mm ultrasound transducer but was induced after 0.04 kJ had been delivered with the laser. We evaluated the iatrogenic risk under normal conditions of use by delivering the shocks tangentially to the ureteral wall and perpendicular to the bladder wall. We sacrificed animals on days 0, 1, and 6. The immediate histologic lesions induced by the Lithoclast and the ultrasound lithotripter were similar, consisting of a moderate reduction of the epithelial layers or intraepithelial detachments. Electrohydraulic shocks induced almost complete abrasion of the urothelium, and the laser induced extensive lesions of partial or complete necrosis of the urothelial wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Thoracoscopic ultrasonic localisation of lung nodules: initial results of an in-vitro and in-vivo study

The main problem in thoracoscopic resection of lung nodules is the difficulty in localising the target. In the following we describe the use of an ultrasonographic, deflectable linear array probe of 7.5 MHz which was first tested during an in-vitro study. This study has provided useful information with respect to the US inspection of normal parenchyma and lung nodules. Initial results in clinical use in 14 patients demonstrate some limitations linked to the difficulty in manoeuvering the probe and to the remaining air in the parenchyma. However, endoscopic US is an interesting additional tool during thoracoscopic exploration of the lung.

[Laparoscopic treatment of vesico-ureteral reflux in the pig. Preliminary report]

Laparoscopic urological surgery is currently in a phase of development. In order to evaluate the possibility of treating vesicoureteric reflux by laparoscopy, we performed an elongation of the submucosal ureteric tract via an extravesical approach (Lich-Gregoir) in 4 pigs. After creating a pneumoperitoneum, 4 trocars were introduced into the abdominal cavity. The peritoneum was incised at the level of the iliac vessels and the ureter was released at its middle portion as far as the ureterovesical junction. After coagulation, the detrusor was then incised proximally in relation to the ureterovesical junction, revealing 3 to 4 cm of vesical mucosa. The ureter was buried in the muscular groove, the edges of which were brought together by means of 6 metal staples. In 3 pigs, the bladder and ureter were immediately removed by laparotomy. On macroscopic examination, the staples correctly approximated the muscle layer without transfixing the bladder mucosa or ureter. The patency of the ureter was assessed with a probe. The submucosal tract was sufficiently large, preventing any ureteric compression. In 1 pig, the ureteric meati were incised endoscopically to create reflux. After laparoscopic elongation of the submucosal tract on one side, only the untreated ureter continued to reflux. Correction of vesicoureteric reflux is technically feasible in the pig. Longer studies are necessary before considering the application of this technique to man.