Microwave Thermoablation of Colorectal Liver Metastases Close to Large Hepatic Vessels Under Pringle Maneuver Minimizes the "Heat Sink Effect".

BACKGROUND: Liver resection and thermoablation are the mainstay of the surgical management of colorectal liver metastases (CRLM). The main limitation of thermoablation is the "heat-sink" effect for nodules next to large vessels. Herein, we report the preliminary results of microwave ablation (MWA) with associated Pringle maneuver to overcome this flaw. METHODS: From November 2017, we performed intraoperative MWA with Pringle maneuver for nodules ≤3 cm with immediate proximity to large vessels (distance ≤ 5 mm, diameter ≥ 3 mm). We collected characteristics of nodules, surgical procedures and postoperative morbidity. Diameter of the ablation area, especially the ablative minimal margin, was calculated for each nodule. Recurrence was also evaluated. RESULTS: Nineteen patients underwent MWA with Pringle maneuver for 23 nodules. Nineteen (83%) ablated nodules were located in segments VI, VII and VIII, and one nodule was in segment I. Median size of nodules was 15 mm (10-21). No deaths occurred. Six patients (38%) experienced complications, among them only one was subsequent to the thermal ablation. Ablative minimal margin was ≥5 mm for 19 (83%) nodules. Margin was not sufficient for four nodules, among them only 2/23 cases (8.7%) of in situ recurrence occurred after 12 months of median follow-up. CONCLUSIONS: In this preliminary study, MWA with Pringle maneuver was associated with a low related morbidity rate and favorable oncological outcome, especially when the radiological minimal margin was sufficient.

[Effects of met-enkephalin on the testis. I. Structural study]. / Efectos de la met-encefalina sobre el testículo. I. Estudio estructural.

We performed a structural study on rat testis using the hematoxylin-eosin and azocarmine staining methods. For the study, we utilized 105 male Wistar rats weighing 280-300 gms. Thirty rats comprised the control group, and 75 comprised the study group. Rats in the study group received a single, acute intracardiac dose of met-enkephalin (100 microliters of 50% met-enkephalin solution) and were sacrificed at 15, 30 and 60 minutes following injection, or a chronic intramuscular dose (50 microliters of 40% met-enkephalin solution) for 10 or 20 days. We observed marked numeric and morphologic changes in Leydig cells, as well as a blockade of spermatogenesis that led to a fall in spermatozoids and secondary spermatocytes. These changes were observed in all rats that had been submitted either to acute or chronic treatment, and were more marked in those where the interval between commencement of treatment and sacrifice was longer. These findings demonstrate that enkephalins (endogenous opiates) can cause profound endocrine and seminal lesions in the rat testis.

[Effects of met-enkephalin on the testis. III. Histoenzymatic study]. / Efectos de la met-encefalina sobre el testículo. III. Estudio histoenzimológico.

We studied the testis of Wistar rats weighing 280-300 gms. following the administration of a single, acute intracardiac dose of methionine-enkephalin (100 microliters of 50% met-enkephalin solution), or a chronic intramuscular dose (50 microliters of 40% met-enkephalin solution). Rats were sacrificed at 15, 30 and 60 minutes following acute injection. Those on chronic treatment were injected once daily for 10 or 20 days. For the study, we utilized 105 male Wistar rats; 30 comprised the control group, and 75 comprised the study group. The following staining methods were used: 1) succinate dehydrogenase, 2) lactate dehydrogenase, 3) ATPase, 4) acid phosphatase, 5) alkaline phosphatase. We observed marked histoenzymological changes in the rat testis. Particularly noteworthy was a marked change in the energy pathways consisting of a decreased activity of aerobic pathways (decreased SDH activity), increased anaerobic activity (increased LDH activity), and consequently, decreased cellular energy stores (decreased ATPase activity). Similarly, changes were observed in other nonspecific enzymes that led to a fall in acid phosphatase activity and a rise in alkaline phosphatase activity.