Current status of pancreatic cancer with oligometastasis.

BACKGROUND: Pancreatic cancer is the seventh leading cause of death worldwide, with ductal adenocarcinoma as the most frequent neoplasm. Half of the patients who are diagnosed have metastases at the time of diagnosis. OBJECTIVE: A review of the treatment of resectable pancreatic adenocarcinoma with oligometastatic disease was carried out in order to present an overview of the existing evidence. METHOD: A bibliographic search was carried in PubMed/Medline, Clinical Key and Index Medicus vhith MESH terms, from the year 1993 to 2022. RESULTS: Patients with liver or lung metastases due to pancreatic ductal adenocarcinoma who undergo surgery and chemotherapy have a longer survival in carefully selected patients. CONCLUSIONS: The evidence regarding surgery in patients with pancreatic ductal adenocarcinoma and oligometastasis is limited and further randomized controlled trials are needed for both scenarios. As well as established criteria that help the selection of patients who can receive this type of treatment.

ANTECEDENTES: El cáncer pancreático es la séptima causa de muerte en el mundo, siendo el adenocarcinoma ductal del páncreas la neoplasia más frecuente. La mitad de los pacientes que son diagnosticados presentan metástasis al momento del diagnóstico. OBJETIVO: Se realizó una revisión sobre el tratamiento del adenocarcinoma pancreático resecable con enfermedad oligometastásica con el fin de presentar un panorama sobre la evidencia existente. MÉTODO: Se realizó una búsqueda bibliográfica en PubMed/Medline, Clinical Key e Index Medicus con términos MESH desde 1993 hasta 2022. RESULTADOS: Los pacientes con metástasis hepáticas o pulmonares por adenocarcinoma ductal de páncreas que son sometidos a cirugía y quimioterapia tienen una mayor sobrevida en casos cuidadosamente seleccionados. CONCLUSIONES: La evidencia respecto a la cirugía en pacientes con adenocarcinoma ductal de páncreas y oligometástasis es limitada y se necesitan ensayos controlados aleatorizados adicionales para ambos escenarios, así como criterios bien establecidos que ayuden a la selección de los pacientes que pueden recibir este tipo de tratamiento.

Retromer dysfunction in amyotrophic lateral sclerosis.

Retromer is a heteropentameric complex that plays a specialized role in endosomal protein sorting and trafficking. Here, we report a reduction in the retromer proteins-vacuolar protein sorting 35 (VPS35), VPS26A, and VPS29-in patients with amyotrophic lateral sclerosis (ALS) and in the ALS model provided by transgenic (Tg) mice expressing the mutant superoxide dismutase-1 G93A. These changes are accompanied by a reduction of levels of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluA1, a proxy of retromer function, in spinal cords from Tg SOD1G93A mice. Correction of the retromer deficit by a viral vector expressing VPS35 exacerbates the paralytic phenotype in Tg SOD1G93A mice. Conversely, lowering Vps35 levels in Tg SOD1G93A mice ameliorates the disease phenotype. In light of these findings, we propose that mild alterations in retromer inversely modulate neurodegeneration propensity in ALS.

Immune checkpoint inhibition in patients with inactive pre-existing neuromuscular autoimmune diseases.

OBJECTIVES: To evaluate the safety of immune checkpoint inhibitor use in patients with pre-existing neurological autoimmune diseases. METHODS: In this retrospective case-series, we examined exacerbations of underlying disease and the occurrence of immune-related adverse events in 5 patients who had been diagnosed with a neurological autoimmune disease prior to receiving immune checkpoint inhibitor therapy for advanced malignancy. RESULTS: Two patients had a prior diagnosis of myasthenia gravis, two had Guillain-Barré syndrome, and one had chronic idiopathic demyelinating polyneuropathy. Only one patient experienced a flare of neurological autoimmune disease. Four of the five patients experienced immune-related adverse events unrelated to their neurological disease. CONCLUSIONS: In this case-series, exacerbations of neurological autoimmune disease were less common and less severe than expected. Further research is needed to determine which individuals are at greatest risk of neurological autoimmune disease complication while receiving immune checkpoint inhibitor therapy.

Systematic elucidation of neuron-astrocyte interaction in models of amyotrophic lateral sclerosis using multi-modal integrated bioinformatics workflow.

Cell-to-cell communications are critical determinants of pathophysiological phenotypes, but methodologies for their systematic elucidation are lacking. Herein, we propose an approach for the Systematic Elucidation and Assessment of Regulatory Cell-to-cell Interaction Networks (SEARCHIN) to identify ligand-mediated interactions between distinct cellular compartments. To test this approach, we selected a model of amyotrophic lateral sclerosis (ALS), in which astrocytes expressing mutant superoxide dismutase-1 (mutSOD1) kill wild-type motor neurons (MNs) by an unknown mechanism. Our integrative analysis that combines proteomics and regulatory network analysis infers the interaction between astrocyte-released amyloid precursor protein (APP) and death receptor-6 (DR6) on MNs as the top predicted ligand-receptor pair. The inferred deleterious role of APP and DR6 is confirmed in vitro in models of ALS. Moreover, the DR6 knockdown in MNs of transgenic mutSOD1 mice attenuates the ALS-like phenotype. Our results support the usefulness of integrative, systems biology approach to gain insights into complex neurobiological disease processes as in ALS and posit that the proposed methodology is not restricted to this biological context and could be used in a variety of other non-cell-autonomous communication mechanisms.

Deletion of Ripk3 Prevents Motor Neuron Death In Vitro but not In Vivo.

Increasing evidence suggests that necroptosis, a form of programmed cell death (PCD), contributes to neurodegeneration in several disorders, including ALS. Supporting this view, investigations in both in vitro and in vivo models of ALS have implicated key molecular determinants of necroptosis in the death of spinal motor neurons (MNs). Consistent with a pathogenic role of necroptosis in ALS, we showed increased mRNA levels for the three main necroptosis effectors Ripk1, Ripk3, and Mlkl in the spinal cord of mutant superoxide dismutase-1 (SOD1G93A) transgenic mice (Tg), an established model of ALS. In addition, protein levels of receptor-interacting protein kinase 1 (RIPK1; but not of RIPK3, MLKL or activated MLKL) were elevated in spinal cord extracts from these Tg SOD1G93A mice. In postmortem motor cortex samples from sporadic and familial ALS patients, no change in protein levels of RIPK1 were detected. Silencing of Ripk3 in cultured MNs protected them from toxicity associated with SOD1G93A astrocytes. However, constitutive deletion of Ripk3 in Tg SOD1G93A mice failed to provide behavioral or neuropathological improvement, demonstrating no similar benefit of Ripk3 silencing in vivo. Lastly, we detected no genotype-specific myelin decompaction, proposed to be a proxy of necroptosis in ALS, in either Tg SOD1G93A or Optineurin knock-out mice, another ALS mouse model. These findings argue against a role for RIPK3 in Tg SOD1G93A-induced neurodegeneration and call for further preclinical investigations to determine if necroptosis plays a critical role in the pathogenesis of ALS.

Glucocerebrosidase gene therapy prevents α-synucleinopathy of midbrain dopamine neurons.

Diminished lysosomal function can lead to abnormal cellular accumulation of specific proteins, including α-synuclein, contributing to disease pathogenesis of vulnerable neurons in Parkinson's disease (PD) and related α-synucleinopathies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase (GCase), and mutations in GBA1 are a prominent genetic risk factor for PD. Previous studies showed that in sporadic PD, and in normal aging, GCase brain activity is reduced and levels of corresponding glycolipid substrates are increased. The present study tested whether increasing GCase through AAV-GBA1 intra-cerebral gene delivery in two PD rodent models would reduce the accumulation of α-synuclein and protect midbrain dopamine neurons from α-synuclein-mediated neuronal damage. In the first model, transgenic mice overexpressing wildtype α-synuclein throughout the brain (ASO mice) were used, and in the second model, a rat model of selective dopamine neuron degeneration was induced by AAV-A53T mutant α-synuclein. In ASO mice, intra-cerebral AAV-GBA1 injections into several brain regions increased GCase activity and reduced the accumulation of α-synuclein in the substantia nigra and striatum. In rats, co-injection of AAV-GBA1 with AAV-A53T α-synuclein into the substantia nigra prevented α-synuclein-mediated degeneration of nigrostriatal dopamine neurons by 6 months. These neuroprotective effects were associated with altered protein expression of markers of autophagy. These experiments demonstrate, for the first time, the neuroprotective effects of increasing GCase against dopaminergic neuron degeneration, and support the development of therapeutics targeting GCase or other lysosomal genes to improve neuronal handling of α-synuclein.

Sustained Systemic Glucocerebrosidase Inhibition Induces Brain α-Synuclein Aggregation, Microglia and Complement C1q Activation in Mice.

AIMS: Loss-of-function mutations in GBA1, which cause the autosomal recessive lysosomal storage disease, Gaucher disease (GD), are also a key genetic risk factor for the α-synucleinopathies, including Parkinson's disease (PD) and dementia with Lewy bodies. GBA1 encodes for the lysosomal hydrolase glucocerebrosidase and reductions in this enzyme result in the accumulation of the glycolipid substrates glucosylceramide and glucosylsphingosine. Deficits in autophagy and lysosomal degradation pathways likely contribute to the pathological accumulation of α-synuclein in PD. In this report we used conduritol-ß-epoxide (CBE), a potent selective irreversible competitive inhibitor of glucocerebrosidase, to model reduced glucocerebrosidase activity in vivo, and tested whether sustained glucocerebrosidase inhibition in mice could induce neuropathological abnormalities including α-synucleinopathy, and neurodegeneration. RESULTS: Our data demonstrate that daily systemic CBE treatment over 28 days caused accumulation of insoluble α-synuclein aggregates in the substantia nigra, and altered levels of proteins involved in the autophagy lysosomal system. These neuropathological changes were paralleled by widespread neuroinflammation, upregulation of complement C1q, abnormalities in synaptic, axonal transport and cytoskeletal proteins, and neurodegeneration. INNOVATION: A reduction in brain GCase activity has been linked to sporadic PD and normal aging, and may contribute to the susceptibility of vulnerable neurons to degeneration. This report demonstrates that systemic reduction of GCase activity using chemical inhibition, leads to neuropathological changes in the brain reminiscent of α-synucleinopathy. CONCLUSIONS: These data reveal a link between reduced glucocerebrosidase and the development of α-synucleinopathy and pathophysiological abnormalities in mice, and support the development of GCase therapeutics to reduce α-synucleinopathy in PD and related disorders.

Mean platelet volume as a novel predictor of systemic inflammatory response in cirrhotic patients with culture-negative neutrocytic ascites.

AIM: To identify a mean platelet volume (MPV) cutoff value which should be able to predict the presence of bacterial infection. METHODS: An observational, analytic, retrospective study. We evaluated medical records of cirrhotic patients who were hospitalized from January 2012 to January 2014 at the Gastroenterology Department of "Hospital General de México Dr. Eduardo Liceaga", we included 51 cirrhotic patients with ascites fluid infection (AFI), and 50 non-infected cirrhotic patients as control group. Receiver operator characteristic curves were used to identify the best cutoff value of several parameters from hematic cytometry, including MPV, to predict the presence of ascites fluid infection. RESULTS: Of the 51 cases with AFI, 48 patients (94.1%) had culture-negative neutrocytic ascites (CNNA), 2 (3.9%) had bacterial ascites, and one (2%) had spontaneous bacterial peritonitis. Infected patients had greater count of leucocytes and polymorphonuclear cells, greater levels of MPV and cardiac frequency (P < 0.0001), and lower mean arterial pressure compared with non-infected patients (P = 0.009). Leucocytes, polymorphonuclear count, MPV and cardiac frequency resulted to be good or very good predictive variables of presence of AFI in cirrhotic patients (area under the receiving operating characteristic > 0.80). A cutoff MPV value of 8.3 fl was the best to discriminate between cirrhotic patients with AFI and those without infection. CONCLUSION: Our results support that MPV can be an useful predictor of systemic inflammatory response syndrome in cirrhotic patients with AFI, particularly CNNA.

Metadoxine improves the three- and six-month survival rates in patients with severe alcoholic hepatitis.

AIM: To evaluate the impact of metadoxine (MTD) on the 3- and 6-mo survival of patients with severe alcoholic hepatitis (AH). METHODS: This study was an open-label clinical trial, performed at the "Hospital General de México, Dr. Eduardo Liceaga". We randomized 135 patients who met the criteria for severe AH into the following groups: 35 patients received prednisone (PDN) 40 mg/d, 35 patients received PDN+MTD 500 mg three times daily, 33 patients received pentoxifylline (PTX) 400 mg three times daily, and 32 patients received PTX+MTD 500 mg three times daily. The duration of the treatment for all of the groups was 30 d. RESULTS: In the groups treated with the MTD, the survival rate was higher at 3 mo (PTX+MTD 59.4% vs PTX 33.3%, P = 0.04; PDN+MTD 68.6% vs PDN 20%, P = 0.0001) and at 6 mo (PTX+MTD 50% vs PTX 18.2%, P = 0.01; PDN+MTD 48.6% vs PDN 20%, P = 0.003) than in the groups not treated with MTD. A relapse in alcohol intake was the primary independent factor predicting mortality at 6 mo. The patients receiving MTD maintained greater abstinence than those who did not receive it (74.5% vs 59.4%, P = 0.02). CONCLUSION: MTD improves the 3- and 6-mo survival rates in patients with severe AH. Alcohol abstinence is a key factor for survival in these patients. The patients who received the combination therapy with MTD were more likely to maintain abstinence than those who received monotherapy with either PDN or PTX.

Assessing potato tuber diel growth by means of X-ray computed tomography.

The formation and development of belowground organs is difficult to study. X-ray computed tomography (CT) provides the possibility to analyse and interpret subtle volumetric changes of belowground organs such as tubers, storage roots and nodules. Here, we report on the establishment of a method based on a voxel dimension of 240 µm and precision (standard deviation) of 30 µL that allows interpreting growth differences among potato tubers happening within 3 h. Plants were not stressed by the application of X-ray radiation, which was shown both by morphological comparison with control plants and by analysis of lipid peroxidation as a measure of oxidative stress. Diel (24 h) tuber growth fluctuations of three potato genotypes were monitored in soil-filled pots of 10 L. In contrast to the results from previous reports, most tubers grew at similar rates during day and night. Tuber growth was not related to the developmental stage of plants and tubers. Pronounced differences were observed between average growth rates in different tubers within a plant. These results are discussed in the context of restrictions of past methods to study tuber growth and in the context of their potential for the characterization of the formation and development of other belowground plant organs.

Successful function of autologous iPSC-derived dopamine neurons following transplantation in a non-human primate model of Parkinson's disease.

Autologous transplantation of patient-specific induced pluripotent stem cell (iPSC)-derived neurons is a potential clinical approach for treatment of neurological disease. Preclinical demonstration of long-term efficacy, feasibility, and safety of iPSC-derived dopamine neurons in non-human primate models will be an important step in clinical development of cell therapy. Here, we analyzed cynomolgus monkey (CM) iPSC-derived midbrain dopamine neurons for up to 2 years following autologous transplantation in a Parkinson's disease (PD) model. In one animal, with the most successful protocol, we found that unilateral engraftment of CM-iPSCs could provide a gradual onset of functional motor improvement contralateral to the side of dopamine neuron transplantation, and increased motor activity, without a need for immunosuppression. Postmortem analyses demonstrated robust survival of midbrain-like dopaminergic neurons and extensive outgrowth into the transplanted putamen. Our proof of concept findings support further development of autologous iPSC-derived cell transplantation for treatment of PD.

Pharmacological rescue of mitochondrial deficits in iPSC-derived neural cells from patients with familial Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disorder caused by genetic and environmental factors that results in degeneration of the nigrostriatal dopaminergic pathway in the brain. We analyzed neural cells generated from induced pluripotent stem cells (iPSCs) derived from PD patients and presymptomatic individuals carrying mutations in the PINK1 (PTEN-induced putative kinase 1) and LRRK2 (leucine-rich repeat kinase 2) genes, and compared them to those of healthy control subjects. We measured several aspects of mitochondrial responses in the iPSC-derived neural cells including production of reactive oxygen species, mitochondrial respiration, proton leakage, and intraneuronal movement of mitochondria. Cellular vulnerability associated with mitochondrial dysfunction in iPSC-derived neural cells from familial PD patients and at-risk individuals could be rescued with coenzyme Q(10), rapamycin, or the LRRK2 kinase inhibitor GW5074. Analysis of mitochondrial responses in iPSC-derived neural cells from PD patients carrying different mutations provides insight into convergence of cellular disease mechanisms between different familial forms of PD and highlights the importance of oxidative stress and mitochondrial dysfunction in this neurodegenerative disease.

Effect of a commercial pectinmethylesterase on tomato paste consistency

Background: Consistency is one of the main traits that define commercial quality and price of tomato paste. Pectins are partially responsible for consistency in tomato paste, therefore enzymatic pectin modification could be used to increase paste consistency. Results: This work reports the effects of a commercial enzymatic preparation of pectin-methyl-esterase (PME) (NovoShape™) on tomato paste consistency taking into account variables as enzyme/substrate ratio (0,1 percent w/w - 1 percent w/w), reaction time (0 hr - 3 hrs) and reaction temperature (40ºC-60ºC). The results indicate that NovoShape™ increased consistency when reaction temperature ranged from 40 to 50ºC with an enzyme/substrate ratio of 0.5 to 1 (l PME solution/g tomato paste on dry base). On the other hand, enzymatic treatment was not effective at 60ºC with an enzyme/substrate ratio of 0.1 percent. Conclusions: Based on these results, addition of NovoShape™ is a good technological approach to increase tomato paste consistency.

Duodeno-biliary obstruction in Peutz-Jeghers syndrome.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a pathology with autosomal dominant inheritance characterized by the presence of hamartomatous polyposis and mucocutaneous pigmentation. We present a case report from the Hospital General of Mexico. CLINICAL CASE: We present the case of a 28-year-old male. During physical examination we noted hyperpigmented dermatosis of the oral mucosa and lips. The same condition was seen in both palms. The condition evolved with intolerance to oral feeding and progressive obstructive jaundice. Panendoscopy reported pangastric sessile polyps, as well as being pylorus passable. In the second duodenal portion occupying the region of the ampoule of Vater was a sessile polyp that deformed the region. Exit of bile was not observed through the ampoule. Ultrasound and computed tomography of the abdomen corroborated dilatation of the extrahepatic biliary tract. Two endoprostheses were placed in the bile duct by endoscopic cholangiography, with improvement of biliary obstruction. Roux-en-Y astrojejunoanastomosis was performed because of obstruction of the duodenum by polyps between the second and third portion. Jejunal enterotomy was necessary because of the presence of intraluminal injury formed by a conglomerate of polyps. The patient had a satisfactory evolution. Pathological study reported hamartomatous polyps. CONCLUSIONS: Duodenal obstruction secondary to biliary tract obstruction is a rare manifestation associated with PJS. In these cases, the treatment of choice is polyp resection using endoscopic and/or surgical approach as well as management of the biliary tract obstruction.

Differentiation of human ES and Parkinson's disease iPS cells into ventral midbrain dopaminergic neurons requires a high activity form of SHH, FGF8a and specific regionalization by retinoic acid.

The cardinal motor symptoms of Parkinson's disease (PD) are caused by the vulnerability to dysfunction and degeneration of ventral midbrain (VM) dopaminergic (DA) neurons. A major limitation for experimental studies of current ES/iPS cell differentiation protocols is the lack of VM DA neurons with a stable phenotype as defined by an expression marker code of FOXA2/TH/ß-tubulin. Here we demonstrate a combination of three modifications that were required to produce VM DA neurons. Firstly, early and specific exposure to 10(-)(8)M (low dose) retinoic acid improved the regional identity of neural progenitor cells derived from human ES cells, PD or healthy subject-specific iPS cells. Secondly, a high activity form of human sonic hedgehog established a sizeable FOXA2(+) neural progenitor cell population in vitro. Thirdly, early exposure to FGF8a, rather than Fgf8b, and WNT1 was required for robust differentiation of the FOXA2(+) floor plate-like human neural progenitor cells into FOXA2(+) DA neurons. FOXA2(+) DA neurons were also generated when this protocol was adapted to feeder-free conditions. In summary, this new human ES and iPS cell differentiation protocol using FGF8a, WNT1, low dose retinoic acid and a high activity form of SHH can generate human VM DA neurons that are required for relevant new bioassays, drug discovery and cell based therapies for PD.

[Trans- and early postoperative complications in gastric surgery for gastric carcinoma. Experience from the General Hospital of Mexico]. / Morbilidad y mortalidad trans y posoperatoria temprana en cáncer gástrico. Experiencia en el Hospital General de México.

OBJECTIVE: We undertook this study to determine the morbimortality in gastric surgery for gastric carcinoma. METHODS: We carried out a retrospective, observational study performed at the Gastroenterology Service of the General Hospital of Mexico City between January 2004 and October 2005. Variables included sex, age, diagnosis, surgery performed and trans- and postoperative complications. RESULTS: Clinical files of 2208 patients were reviewed: 36 (1.63%) cases with gastric carcinoma were found. Twenty patients fulfilled inclusion criteria; there were nine (45%) females and 11 (55%) males with a median age of 60.3 years. Radiological studies performed were upper gastrointestinal series, esophagogastroduodenoscopy, chest x-ray, and computed tomography (CT). Localization of the tumors was as follows: 15 in the antrum, three in the fundus and body and two in the body portion of the stomach. Clinical staging was T3 N0 M0. Surgical procedures were as follows: 11 partial gastrectomies and 4 gastrojejunostomies. In three cases, total gastrectomy was done and in two cases lymphatic biopsy was done. No mortality was reported. Morbidity was reported in one case (5%) with enterocutaneous fistula. CONCLUSIONS: Surgery is the treatment for gastric carcinoma. Preoperative staging is done with CT and laparoscopy. There was no mortality in our study. Morbidity is similar to that reported by other hospitals.

Morbilidad y mortalidad trans y posoperatoria temprana en cáncer gástrico: experiencia en el Hospital General de México / Trans- and early postoperative complications in gastric surgery for gastric carcinoma: experience from the General Hospital of Mexico

OBJECTIVE: We undertook this study to determine the morbimortality in gastric surgery for gastric carcinoma. METHODS: We carried out a retrospective, observational study performed at the Gastroenterology Service of the General Hospital of Mexico City between January 2004 and October 2005. Variables included sex, age, diagnosis, surgery performed and trans- and postoperative complications. RESULTS: Clinical files of 2208 patients were reviewed: 36 (1.63%) cases with gastric carcinoma were found. Twenty patients fulfilled inclusion criteria; there were nine (45%) females and 11 (55%) males with a median age of 60.3 years. Radiological studies performed were upper gastrointestinal series, esophagogastroduodenoscopy, chest x-ray, and computed tomography (CT). Localization of the tumors was as follows: 15 in the antrum, three in the fundus and body and two in the body portion of the stomach. Clinical staging was T3 N0 M0. Surgical procedures were as follows: 11 partial gastrectomies and 4 gastrojejunostomies. In three cases, total gastrectomy was done and in two cases lymphatic biopsy was done. No mortality was reported. Morbidity was reported in one case (5%) with enterocutaneous fistula. CONCLUSIONS: Surgery is the treatment for gastric carcinoma. Preoperative staging is done with CT and laparoscopy. There was no mortality in our study. Morbidity is similar to that reported by other hospitals.

The role of photochemical quenching and antioxidants in photoprotection of Deschampsia antarctica.

Deschampsia antarctica Desv. (Poaceae) is the only grass that grows in the maritime Antarctic. Constant low temperatures and episodes of high light are typical conditions during the growing season at this latitude. These factors enhance the formation of active oxygen species and may cause photoinhibition. Therefore, an efficient mechanism of energy dissipation and / or scavenging of reactive oxygen species (ROS) would contribute to survival in this harsh environment. In this paper, non-acclimated and cold-acclimated D. antarctica were subjected to high light and / or low temperature for 24 h. The contribution of non-photochemical dissipation of excitation light energy and the activities of detoxifying enzymes in the development of resistance to chilling induced photoinhibition were studied by monitoring PSII fluorescence, total soluble antioxidants, and pigments contents and measuring variations in activity of superoxide dismutase (SOD; EC 1.15.1.1), ascorbate peroxidase (APX; EC 1.11.1.11), and glutathione reductase (GR; EC 1.6.4.2). The photochemical efficiency of PSII, measured as Fv / F m, and the yield of PSII electron transport (ΦPSII) both decreased under high light and low temperatures. In contrast, photochemical quenching (qP) in both non-acclimated and cold-acclimated plants remained relatively constant (approximately 0.8) in high-light-treated plants. Unexpectedly, qP was lower (0.55) in cold-acclimated plants exposed to 4°C and low light intensity. Activity of SOD in cold-acclimated plants treated with high light at low temperature showed a sharp peak 2-4 h after the beginning of the experiment. In cold-acclimated plants APX remained high with all treatments. Activity of GR decreased in cold-acclimated plants. Compared with other plants, D. antarctica exhibited high levels of SOD and APX activity. Pigment analyses show that the xanthophyll cycle is operative in this plant. We propose that photochemical quenching and particularly the high level of antioxidants help D. antarctica to resist photoinhibitory conditions. The relatively high antioxidant capacity of D. antarctica may be a determinant for its survival in the harsh Antarctic environment.

Tratamiento de las lesiones quirúrgicas de las vías biliares / Treatment of biliary tract surgical lesions

Objetivo: dar a conocer la experiencia de los autores en el tratamiento de las lesiones posquirúrgicas de las vías biliares.Material y método: estudio retrospectivo de enero de 1994 a diciembre de 1998, analizando los expedientes de todos los pacientes con lesión transoperatoria de vías biliares, tanto laparoscópica como abierta, se revisaron los datos clínicos, de laboratorio, gabinete y el tratamiento utilizado, así como su evolución. Resultados: se encontraron 13 casos, nueve mujeres (69.2 por ciento) y cuatro hombres (30.8 por ciento). Ocho casos fueron sometidos a colecistectomía abierta, cinco a cirugía laparoscópica. En todos se observó ictericia obstructiva. La bilirrubina directa en promedio fue de 3.3 mg/dL. Los estudios de gabinete incluyeron ultrasonograma, colangiografía endoscópica o percutánea.En cinco casos con lesión Bismuth tipo II y en un caso con tipo I, con estenosis parcial, fueron manejados con colocación de prótesis endobiliar. Un paciente con Bismuth tipo I fue tratado con coledocoduodeno-anastomosis y a seis casos tipo II se les realizó hepatoyeyuno-anastomosis. No se encontró morbimortalidad posterior al tratamiento.Se concluye que las lesiones biliares posquirúrgicas parciales pueden manejarse satisfactoriamente con prótesis endobiliares, reservando la derivación quirúrgica a las lesiones completas.Palabras clave: lesión-vía-biliar, Bismuth, colangiografía, prótesis-endobiliar, coledocoduodenoanastomosis, hepatoyeyunoanastomosis, ictericia-obstructiva.