Irreversible electroporation: Beyond the limits of tumor ablation.

Irreversible Electroporation (IRE) is a non-thermal tumor ablation technique. High-voltage electrical pulses are applied between pairs of electrodes inserted around and/or inside a tumor. The generated electric current induces the creation of nanopores in the cell membrane, triggering apoptosis. As a result, IRE can be safely used in areas near delicate vascular structures where other thermal ablation methods are contraindicated. Currently, IRE has demonstrated to be a successful ablation technique for pancreatic, renal, and liver tumors and is widely used as a focal therapeutic option for prostate cancer. The need for specific anesthetic management and accurate parallel placement of multiple electrodes entails a high level of complexity and great expertise from the interventional team is required. Nevertheless, IRE is a very promising technique with a remarkable systemic immunological capability and may impact on distant metastases (abscopal effect).

[Postoperative hyponatremia in pediatric patients]. / Hiponatremia postoperatoria en pacientes pediátricos.

Fluid replacement therapy for pediatric patients in the past 50 years has meant the infusion of hypotonic solutions in amounts calculated using the Holliday-Segar formula. Recent studies have focused attention on the incidence of postoperative hyponatremia and associated morbidity and mortality rates, generating debate on the advisability of perioperative fluid therapy and calling into question both the effectiveness of this strategy and the quantities used. We report 3 cases of hyponatremic encephalopathy in children following different types of minor surgery. Free water excretion by the kidneys is known to be a conditioning factor in this therapy, yet the ideal way to provide pediatric fluid therapy is still hotly debated. The question cannot be resolved until large randomized clinical trials are carried out to compare the use of hypotonic and isotonic solutions. Some general recommendations can be offered, however, in the interest of lowering the incidence of electrolyte disturbances and diminishing their repercussions.

Delineation of molecular species of a family of diacyltrehaloses from Mycobacterium fortuitum by mass spectrometry.

A family of 2,3-di-O-acyl trehaloses (DAT), previously identified in Mycobacterium fortuitum, was studied by fast-atom bombardment mass spectrometry to establish the combinations of fatty acyl substituents and, hence, to delineate the molecular species there comprised. The mass spectra indicated the possible existence of 41 molecular species, with a total of 35-40 carbon atoms and 0-4 double bonds in the lipid moiety. The principal components were situated a m/z (M+ +23) 919 (formulated as 2-methyloctadec-2-enoyl,2-methyloctadecadienoyl trehalose and as 2-methylhexadec-2-enoyl,2-methyleicosadienoyl trehalose) and m/z (M+ +23) 921 (formulated as di-2-methyloctadec-2-enoyl trehalose and as 2-methylhexadec-2-enoyl,2-methyleicos-2-enoyl trehalose). The data obtained revealed that DAT was composed of three types of combinations of fatty acyl groups; (i) linear plus linear; (ii) linear plus 2-methyl branched; and (iii) 2-methyl branched plus 2-methyl branched.

Doppler-duplex ultrasound in renal colic.

OBJECTIVE: To determine the role of intrarenal Doppler ultrasound (US) in patients with renal colic and to establish the usefulness of this diagnostic method. MATERIALS AND METHODS: In 121 patients with renal colic and 70 healthy individuals, 382 kidneys were examined with color duplex US. Mean intrarenal-arterial resistive index (RI), and the difference of mean RIs (dRI) between both kidneys were determined. In 64 patients, RI and dRI were compared with urographic findings (time of delay pyelogram between both kidneys). RESULTS: In the 70 healthy individuals, RI was 0.62 +/- 0.045 and dRI 0.018 +/- 0.01. In the 121 patients with renal colic, RI (0.71 +/- 0.06) was significantly superior (P < 0.001) with respect to the opposite kidney, with a dRI of 0.09 +/- 0.055. In a correlation performed in 64 patients with urographic findings among color doppler US, with a RI > or = 0.70 and/or dRI > or = 0.06 as an indicative value of obstruction, sensitivity and specificity were 91.8% for patients with delayed pyelogram (n = 37 patients), and 48.1% for patients with nondelayed pyelogram (n = 27 patients) with a specificity of 92.8% with respect to the group of normal patients. In the group of patients with delayed pyelogram, RI was significantly superior (P < 0.05) in patients with an evolution time greater than 24 hours, in patients with proximal ureteral obstruction and in patients who had signs of pyelonephritis. There were no significant differences in the group of patients with nondelayed pyelograms. CONCLUSION: Color Doppler US is useful to fundamentally evaluate the consequences of the obstruction on renal function. Other factors such as evolution time of the symptomology, obstruction level, or existence of pyelonephritis can alter the US-Doppler values.

Transthoracic aspiration biopsy of pulmonary and mediastinal lesions.

Thoracic aspiration biopsy (TAB) constitutes a useful technique in establishing a diagnosis in diseases of the lungs and mediastinum. Results obtained from 1046 fluoroscopically-guided TABs are presented with review of the most important aspects of the technique. Diagnostic accuracy in malignancy detection was 93.8% in lung lesions (n = 984) and 74.5% in mediastinal lesions (n = 62). Sensitivity was higher in peripheral than in central lesions (96% vs. 87%, respectively). Specificity was 100% in both groups. Sensitivity in lesions smaller than 2 cm was 70% and 94% in larger lesions. Aspiration biopsies performed with Chiba and Franseen needles showed a similar sensitivity (95%) higher than with other types of needles. A pneumothorax developed in 138 patients (13.2%). Only eight of these required the use of an endothoracic tube (0.8% of all biopsies).

[Life-threatening hemoptysis. Treatment with transcatheter embolization]. / Hemoptisis amenazante. Tratamiento mediante embolización transcatéter.

OBJECTIVE: To evaluate the immediate and long-term efficacy of transcatheter embolization of bronchial, systemic and pulmonary arteries to treat life-threatening hemoptysis. Likewise, we propose the systematic treatment of life-threatening hemoptysis by means of transcatheter embolization. MATERIAL AND METHODS: One hundred seven angiographies were performed on the same number of patients experiencing life-threatening hemoptysis with bleeding exceeding 150 ml in 24 hours. Before angiography, we rinsed the vessels with cold saline solution and adrenalin through the catheter. Thirty-three patients were female and 74 were male. Mean age was 52.3 years (range 12 to 75 years). Embolization was performed in 104 (3 in patients with recurrent hemoptysis) using polyvinyl alcohol and micro-coils. Bronchial and systemic arteries of the affected hemithorax (mammary and lateral thoracic arteries) were checked in all patients. If findings were negative or bleeding was recurrent, we also performed pulmonary arteriography. RESULTS: In two cases we were unable to catheterize the artery theoretically responsible for bleeding. Examination of both arterial and systemic vessels proved normal in one patient. The embolization technique was successful in 99% (103/104) of the cases and the rate of immediate clinical success was 95.1% (99/104). The mean time of follow-up was 43.2 months (range 3 to 66 months). Hemoptysis recurred in 15.3% (16 cases) within a mean 8.3 months (range 15 days to 48 months); embolization was repeated in 14 of these patients with satisfactory results, while two underwent surgery. In five patients (4.8%) we observed complications requiring no additional medical treatment: one instance of coil migration to the deep femoral artery, from which the coil was removed in a basket; two cases of bronchial artery extravasation with small mediastinal hematomas; and two hematomas at the points of puncture. CONCLUSION: Selective or supra-selective embolization of the arteries that feed the bronchi provides effective management of life-threatening hemoptysis. No additional medical treatment is usually required.

[Lacrimal duct obstruction treated with lacrimonasal stent]. / Obstrucción de vía lagrimal tratada mediante stent lacrimonasal.

OBJECTIVE: To analyze a series of patients with lacrimal duct obstruction treated with polyurethane stents. MATERIAL AND METHODS: We studied 125 cases of lacrimal duct obstruction corresponding to 115 patients, of whom 30 were males (26.08%) and 85 females (73.91%). The obstruction involved the right side in 51 cases (40.8%) and the left side in 74 (59.2%). Mean age was 65 +/- 14.64 years. Symptoms included chronic epiphora in 65 patients (52%), acute lacrimal sac inflammation in 33 (26.4%), mucocele in 6 (4.8%) and recurrent conjunctivitis in 4 (3.2%). Seventeen patients came to us diagnosed with lacrimal duct obstruction. Time of follow up was one year. RESULTS: Stents were successfully implanted in 120 cases (96%). Surgical complications included pain in 5.83%, eyelid inflammation in 5%, nasal bleeding in 0.83% and false duct in 0.83%. Functional success was achieved in 82 patients (68.3%), and surgical failure occurred in 38 patients (31.7%). Mean time of stent failure was 178 days. In these cases, inner granulation tissue was found in 63.15% of the cases and mucoid material in 36.85%. The most common postoperative complication was mucocele formation, which ocurred in 7.5% of the patients. CONCLUSIONS: In our experience, polyurethane stent implantation is a good alternative for treating nasolacrimal obstruction, but not as effective as endonasal or external dacryocystorhinostomy.

[Anesthetic management of a neonate with esophageal atresia, tracheoesophageal fistula and imperforate anus]. / Tratamiento anestésico del neonato con atresia de esófago asociada a fístula traqueoesofágica y ano imperforado.

Esophageal atresia is a rare condition (1:2,500-4,500), incompatible with life, and a surgical emergency in the neonatal period. It is associated with prematurity in 30% of cases, and to congenital abnormalities in 50% of cases, especially cardiac anomalies. Major congenital heart diseases and low weight are independent predictors of mortality and critical perioperative events. The aim of this article is to describe the most significant anaesthetic challenges presented in a case of a term neonate undergoing emergency surgery after being diagnosed with esophageal atresia, tracheoesophageal fistula type iiib/C, and imperforate anus. The major priorities during the anaesthetic management consist of establishing a safe airway and effective pulmonary ventilation that minimises air leakage to the upper digestive tract.

A family of diacyltrehaloses isolated from Mycobacterium fortuitum.

A trehalose-containing glycolipid was detected in several strains of Mycobacterium fortuitum and characterized as 2,3-di-O-acyltrehalose (DAT) by combined NMR spectroscopy, IR spectroscopy, GLC and GLC-MS. Lipid constituents of the molecule were identified as a mixture of straight-chain (14-18 carbon atoms) and methyl-branched-chain (17-21 carbon atoms) fatty acyl groups. DAT was further fractionated by reverse phase TLC into four fractions that were designated DAT-I-DAT-IV. DAT-I contained 70-75% straight-chain acyl substituents (hexadecanoyl and octadecanoyl predominating) and 25-30% 2-methyl branched substituents (mainly 2-methyl octadecadienoyl). DAT-II was composed of a mixture in which the acyl groups were almost exclusively 2-methyl branched, with 2-methyl octadecadienoyl and 2-methyl octadecen-2-oyl predominating. DAT-III, which was the major isolated fraction, consisted of compounds in which the ratio linear to branched acyl groups varied between 0.8 to 0.9, 2-methyl octadecen-2-oyl, hexadecanoyl and octadecanoyl being the most abundant. Finally, DAT-IV comprised a mixture of DAT molecules containing mostly 2-methyl octadecadienoyl, 2-methyl octadecen-2-oyl, 2-methyl eicosadienoyl and 2-methyl eicosen-2-oyl groups.

Acute colorectal obstruction: treatment with self-expandable metallic stents before scheduled surgery--results of a multicenter study.

PURPOSE: To evaluate the efficacy of treatment with self-expandable metallic stents for acute colonic obstruction before elective surgical resection. MATERIALS AND METHODS: In 71 patients with malignant obstruction seen from October 1993 through December 1996, lesions were located in the transverse colon in one patient, in the descending colon in 22 patients, and in the rectosigmoid region in 48. A total of 72 self-expandable metallic stents were implanted within 24 hours of diagnosis. RESULTS: Technical success was obtained in 64 patients (90%). In two cases (3%), it was not possible to advance across the obstructing mass. In five cases (7%), the prostheses were poorly positioned at the site of obstruction, requiring placement of a new stent in three cases. Clinical improvement and resolution of the obstruction were confirmed in 66 patients (93%) within 96 hours. Minor complications developed in nine cases (13%). One patient (1%) underwent surgery to resolve a colonic perforation caused by wires at the ends of the stent. The mean time between stent placement and surgery was 8.6 days (range, 6-16 days). CONCLUSION: Implantation of colorectal stents is a safe treatment of acute malignant colonic obstruction before resection.

[The clinical efficacy and complications of the transjugular intrahepatic portosystemic shunt-stent]. / Eficacia clínica y complicaciones del shunt-stent portosistémico intrahepático transyugular.

TIPSS is a new therapeutic modality for decompressing the portal tree and its use has broadened in the last five years. From February 1993 to August 1994 a prospective study was performed to evaluate its efficacy and safety. Nineteen cirrhotic patients (Child A-5, B-10, and C-4) with a TIPSS placed were included. The mean follow-up was 7.2 months. The indication was therapy of esophageal variceal bleeding in 18 patients (acutely in 8 and elective in 10 patients) and refractory ascites in one. In all cases could the "stent" be placed and the portocaval gradient decreased from 22.8 +/- 3.71 to 9.3 +/- 2.27 mmHg. In the first thirty days the mortality rate was 10.5%, with the following complications: two portal thromboses, two acute non-lithiasic cholecystitis, one hemoperitoneum, one spontaneous bacterial peritonitis, and one hepatic encephalopathy. During the follow-up period two patients developed hemorrhagic relapses and two additional patients subclinical encephalopathy. TIPSS dysfunction was observed in 57.8%.