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Biomedical subjects

M Montoya

Publications and source records attributed to M Montoya.

At least 19 recordsLinked to original sources
PubMed2006

Risk factors of acute renal failure after liver transplantation.

The objective of this study was to determine the risk factors of postoperative acute renal failure (ARF) in orthotopic liver transplantation (OLT). We reviewed 184 consecutive OLT. Postoperative ARF was defined as a persistent rise of 50% increase or more of the S-creatinine (S-Cr). The patients were classified as early postoperative ARF (E-ARF) (first week) and late postoperative ARF (L-ARF) (second to fourth week). Preoperative variables were age, sex, comorbidity, indication for OLT, Child-Pugh stage, united network for organ sharing status, analysis of the blood and urine, and donor's data. Intraoperative variables were systolic arterial pressure, mean arterial pressure, pulmonary capillary wedge pressure, cardiac index, and systemic vascular resistance index. Surgical technique, number of blood products transfused, need for adrenergic agonist drugs, and intraoperative complications were also important. Postoperative variables were duration of stay in the intensive care unit, time on mechanic ventilation, liver graft dysfunction, need for adrenergic agonist drugs, units of blood products infused, episodes of acute rejection, re-operations, and bacterial infections. Firstly we carried out a univariate statistical analysis, and secondly a logistic regression analysis. The risk factors for E-ARF were: pretransplant ARF (odds ratio (OR)=10.2, P=0.025), S-albumin (OR=0.3, P=0.001), duration of treatment with dopamine (OR=1.6, P=0.001), and grade II-IV dysfunction of the liver graft (OR=5.6, P=0.002). The risk factors for L-ARF were: re-operation (OR=3.1, P=0.013) and bacterial infection (OR=2.9, P=0.017). The development of E-ARF is influenced by preoperative factors such as ARF and hypoalbuminemia, as well as postoperative factors such as liver dysfunction and prolonged treatment with dopamine. The predicting factors of L-ARF differ from E-ARF and correspond to postoperative causes such as bacterial infection and surgical re-operation.

Acute Kidney Injury↗
PubMed2005

Attitude toward living related donation of patients on the waiting list for a deceased donor solid organ transplant.

INTRODUCTION: Spain is the country with the highest rate of donation from deceased individuals. However, given the deficit in organs, living donation is being encouraged. Our objective was to analyze attitudes toward living donation among patients on the waiting list for a transplant. MATERIALS AND METHODS: Patients on the waiting list for a kidney or liver transplant (n = 96; 46 kidney and 50 liver) in the last year had their attitudes toward living donation evaluated through a psychosocial survey performed in a direct interview with an independent health professional from the transplant unit and analyzed by Student t test and the chi-square test. RESULTS: Ninety-one percent were in favor of donating their organs when they die, 6% had doubts, and the remaining 3% were against it. Twenty percent would accept living donation from a family member (32% in liver vs 7% in kidney; P < .05), despite 89% of them accepting that there would be a risk to the family member. Twenty percent reported that a family member had suggested donating, but the patient was opposed. Finally, only 6% considered living donation to be their first choice, 42% did not consider this option. Up to 96% would donate an organ to a family member if they were requested to do so. CONCLUSION: Patients on the waiting list are not favorable to living related donation for themselves, although members of their family have proposed it to them. However, the liver patient is more prepared to accept it, possibly because that patient has no other alternative as do kidney patients have dialysis. Even so, they are favorable toward donating a living organ if a family member were to request one. In general, living donation is not being proposed to these patients as a real option, partly because of their doctors.

Adult↗
PubMed2005

Attitude toward xenotransplantation in kidney and liver patients on the transplant waiting list.

INTRODUCTION: The deficit in transplant organs is encouraging research into stem cells and xenotransplantation. However, many studies have shown that using animals for human transplantation could be rejected by society. The objective here was to analyze the attitude of patients on the waiting list toward a possible transplant of an organ of animal origin. MATERIALS AND METHODS: Patients on the waiting list for kidney and liver transplants including last year (n = 96) underwent a direct interview by an independent health professional from the transplant unit. Using a psychosocial survey, an evaluation was made of attitudes toward donation of organs of animal origin and its various options. Student t test and the chi-square test were used for analysis. RESULTS: If results from xenotransplantation could be superimposed onto those of human transplantation, 71% would accept such an organ. In the case of the kidney, 83% would accept, 4% would not, and 13% have doubts; as opposed to 60%, 12%, and 28%, respectively, of liver cases (P < .05). Supposing that the results were worse than in human organs, only 26% would accept an animal organ. Thus, for kidney, 33% would accept it, 48% would not, and 20% would have doubts; and for liver, it would be 20%, 50%, and 30%, respectively. In a life-threatening situation 98% would accept an animal organ as a bridge of hope in the wait for a human organ. In addition, if the organ functioned correctly, 98% would keep the animal organ, thus avoiding an intervention to substitute a human organ. CONCLUSION: If xenotransplantation became a clinical reality, acceptance of an animal organ by patients on the waiting list would be low, especially if the results could not be superimposed onto human ones. Only its use as a bridge until the arrival of a human organ would increase its acceptance.

Animals↗
PubMed2005

Pathology findings in a model of auxiliary liver transplantation with portal vein arterialization in pigs.

OBJECTIVE: To determine the histological findings and temporal evolution that occur in auxiliary liver grafts as a consequence of arterialization of the portal vein (PVA). MATERIALS AND METHODS: We evaluated 10 auxiliary heterotopic liver transplants with arterialization of the PVA. The histological study was performed using an optical microscope to process liver samples with staining using hematoxylin and eosin. A biopsy of native liver tissue was used as a control. RESULTS: Two animals were excluded from the study, one due to ischemic necrosis of the graft and one that died 4 hours after transplant. All of the remaining eight animals underwent a histological study at 1 day, 7 days, and 14 days. The most significant histological findings were: (1) dilation of portal areas and sinusoids, which were detected at 24 hours and persisted; (2) thickening of the interlobular septum, which was observed after day 7 and progressively increased to day 14; (3) bile duct hyperplasia detected at the seventh day. CONCLUSIONS: The consistent, early findings in a pig liver with PVA included vascular dilation of the portal area and the sinusoids, with bile duct hyperplasia extending progressively and the thickening of interlobular connective tissue septa with a generalized perilobular connective tissue reaction, which did not seem to alter the internal structure of the lobule, which showed histologically normal hepatocytes. The fibrous reaction may be the first stage in chronic hepatopathy. Further long-term studies are required in this model.

Animals↗
PubMed2003

Increased gap junctional intercellular communication is directly related to the anti-tumor effect of all-trans-retinoic acid plus tamoxifen in a human mammary cancer cell line.

Additive effects against tumor cells might be achieved by combining anti-neoplastic agents directed against one or more altered mechanisms in cancer. We investigated the participation of gap junctional intercellular communication (GJIC), which is commonly dysfunctional in tumor cells as a possible mediating mechanism of the effect of all-trans-retinoic acid (RA) and tamoxifen (Tx) in MCF-7 human breast cancer cell lines. The combination of RA + Tx stimulated GJIC in approximately 53 +/- 3% of MCF-7 cells as early as after 6 h of treatment remaining communicated through 144 h of culture. The GJIC enhancement occurred along with immunolocalization of Cx26 and 43 at the membrane of contacting cells and correlated with higher protein levels. Cx40 immunoreactive plaques were detected at cell-to-cell contacts during 48 h of RA + Tx treatment that did not involve higher protein expression, to the contrary, a downregulation occurred after 72 h of treatment. Cell proliferation inhibition upon RA + Tx exposure was observed with optimal effects at 96-120 h of culture with an accumulation of cells primarily in G2/M and G0/G1 cell cycle boundaries. An enhancement of the pre-existing E-cadherin levels was observed after drug exposure along with a downregulation of Bcl-2 and C-myc protein levels and a reduction of telomerase activity, suggesting partial tumor phenotype reversion. Blockage of the RA + Tx-induced GJIC with 18-beta-glycyrrhetinic acid (beta-Gly) prevented in 34% the inhibition of MCF-7 proliferation and the E-cadherin increment in 30% at 96 h of culture. GJIC blockage did not alter the downregulation of Bcl-2, c-Myc, or telomerase activity induced by RA + Tx. Our results showed the participation of GJIC as a mediator mechanism of the combined action of RA and Tx in MCF-7 cells. The chemopreventive modulation of GJIC might represent an approachable alternative for the improvement of cancer therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

Does the standard vs piggyback surgical technique affect the development of early acute renal failure after orthotopic liver transplantation?

The objective of this study was to evaluate the effect of the surgical technique on postoperative renal function during the first week after liver transplantation (OLT). We performed a retrospective study of 184 consecutive OLT. Criteria for acute renal failure were: serum creatinine >1.5 mg/dL, an increase by 50% in the baseline serum creatinine, or oliguria requiring renal replacement therapy. The distribution of patients according to the surgical technique was: standard (n=84), venovenous bypass (n=20), and piggyback (n=80). Other variables analyzed were: intraoperative requirement for blood products, treatment with adrenergic agonists, intraoperative complications, and postreperfusion syndrome. Univariate analysis showed the following parameters to be significantly related to postoperative renal failure: intraoperative fresh frozen plasma and cryoprecipitate requirements, intraoperative complications, postreperfusion syndrome, need for noradrenaline or dobutamine, standard surgical technique versus piggyback (39% vs 18%, P<.01) and venovenous vs piggyback (50% vs 18%, P<.01). Logistic regression analysis identified the following variables as having independent prognostic value: (1) Standard surgical technique vs piggyback (OR=3.3, P=.01); (2) venovenous vs piggyback (OR=4.7, P=.02); and (3) >20 U cryoprecipitate requirement (OR=1.04, P=.01). In conclusion, compared with the piggyback technique, the standard surgical technique appears to be an independent risk factor for postoperative acute renal failure. When venovenous bypass is used in patients who do not tolerate trial clamping of inferior vena cava, it does not reduce the incidence of postoperative renal failure. Finally, the piggyback technique significantly reduces the probability of acute renal failure after liver transplantation.

Acute Kidney Injury↗
PubMed2003

Description of a new auxiliary heterotopic partial liver transplantation technique with portal vein arteriolization of applicability in heterotopic liver xenotransplantation.

OBJECTIVE: The aim of this study was to describe a new model of auxiliary heterotopic partial liver transplantation with portal vein arterialization. MATERIALS AND METHODS: Three standard hepatectomies were performed in pigs. The left lateral lobe was surgically resected and portal vein arteriolization constructed by an end-to-side "Y" anastomoses between the distal to the celiac axis aorta and the portal vein. RESULTS: The graft was placed in the left iliaca fossa using anastomoses of the donor infrahepatic inferior cava vein end-to-side to the host infrarenal inferior vein and the donor aortic stump with portal vein arteriolization end-to-side to the left iliac artery. After graft reperfusion, the 3 recipients showed intraoperative hypotension, which was treated with fluid administration and vasoactive drugs. At the end of the operation, the graft displayed normal arterial blood flow and good venous drainage. The donor liver graft appeared more red than the host liver, which was due to the increased arterial blood flow. One pig of 3 died at 24 hours after surgery, probably due to hypothermia. However, the other 2 pigs survived the procedure and remained stable. Echographic monitoring showed intrahepatic arterial expansion, which may be the result of high blood pressure due to the arteriolization procedure. CONCLUSIONS: We have developed a novel and easy to perform technique that diminishes the number of anastomoses and does not involve vessels from other organs.

Anastomosis, Surgical↗
PubMed2003

Diagnosis and treatment of oculopharyngeal dystrophy: a report of three cases from the same family.

Oculopharyngeal muscular dystrophy is a hereditary pathology transmitted in an autosomal dominant manner. The clinical symptoms are palpebral ptosis, oropharyngeal dysphagia and proximal limb weakness. Upper gastro-esophageal endoscopy is recommended to study the dysphagia, a video-radiology study with barium and an esophageal manometry to study the pharyngeo-esophageal motor disorder. Muscle biopsy reveals the presence of atrophic fibers substituted by an increase in fat and connective tissue. In 1998 Brais described the genetic alteration responsible for this pathology, a limited expansion of the triplet of GCG nucleotides in PABP2 gene on chromosome 14q11. Normal individuals have the homozygotic form (GCG)6 of this triplet, whereas patients with the described syndrome have the heterozygotic form (GCG)6-(GCG)9 or (GCG)6-(GCG)10. We present three siblings from the same family with diagnoses and genetic confirmations of oculopharyngeal dystrophy. Two of the patients underwent cricopharyngeal myotomy to relieve the dysphagia.

Aged↗
PubMed2003

Characterization of secreted and intracellular forms of a truncated hepatitis C virus E2 protein expressed by a recombinant herpes simplex virus.

A replication-defective herpes simplex virus type 1 (HSV-1) recombinant lacking the glycoprotein H (gH)-encoding gene and expressing a truncated form of the hepatitis C (HCV) E2 glycoprotein (E2-661) was constructed and characterized. We show here that cells infected with the HSV/HCV recombinant virus efficiently express the HCV E2-661 protein. Most importantly, cellular and secreted E2-661 protein were both readily detected by the E2-conformational mAb H53 and despite the high expression levels, only limited amounts of misfolded aggregates were detected in either the cellular or secreted fractions. Furthermore, cell-associated and secreted E2-661 protein bound to the major extracellular loop (MEL) of CD81 in a concentration-dependent manner and both were highly reactive with sera from HCV-infected patients. Finally, BALB/c mice immunized intraperitoneally with the recombinant HSV/HCV virus induced high levels of anti-E2 antibodies. Analysis of the induced immunoglobulin G (IgG) isotypes showed high levels of IgG2a while the levels of the IgG1 isotype were significantly lower, suggesting a Th1-type of response. We conclude that the HSV-1 recombinant virus represents a promising tool for production of non-aggregated, immunologically active forms of the E2-661 protein and might have potential applications in vaccine development.

Adolescent↗
PubMed2001

Evolution of the need for operation for peptic pyloric stenosis over a period of 24 years (1976-1999).

OBJECTIVE: To analyse the need for operation for pyloric stenosis caused by duodenal ulcer over a period of 24 years (1976-1999). DESIGN: Retrospective study. SETTING: University hospital, Spain. SUBJECTS: 156 patients operated on for peptic pyloric stenosis. MAIN OUTCOME MEASURES: The number of patients operated on yearly were grouped into 4-year periods for statistical comparison. RESULTS: The number of cases operated on each year steadily decreased between 1976 and 1999. In the 1988-1991 period there was a significant reduction (p <0.05), which continued over the next two 4-year periods, particularly the last (p <0.01). CONCLUSION: Although we cannot use this study to establish a direct relation between the decrease in the indication for operations for peptic pyloric stenosis and the use of H2 antagonists, proton pump inhibitors, or treatment to eradicate Helicobacter pylori, we did find a significance difference between the years before and after the introduction of these drugs.

Adult↗
PubMed2000

The estrogen replacement therapy of the Women's Health Initiative promotes the cellular mechanisms of memory and neuronal survival in neurons vulnerable to Alzheimer's disease.

OBJECTIVES: The current study investigated the neurotrophic and neuroprotective action of the complex formulation of conjugated equine estrogens (CEEs), the most frequently prescribed estrogen replacement therapy in the United States and the estrogen replacement therapy of the Women's Health Initiative. METHODS: Videomicroscopic, morphologic and biochemical analyses were conducted in primary cultures of hippocampal neurons to determine the neurotrophic and neuroprotective properties of CEEs. RESULTS: Results of these analyses demonstrated that CEEs significantly increased hippocampal neuronal outgrowth, a cellular marker of memory formation. Dose response analyses indicated that the lowest effective concentration of CEEs exerted the maximal neurotrophic effect. Results of neuroprotection studies demonstrated that CEES induced highly significant neuroprotection against beta amyloid(25-35), hydrogen peroxide and glutamate-induced toxicity. CONCLUSIONS: CEEs induced cellular markers of memory function in neurons critical to memory and vulnerable to negative effects of aging and Alzheimer's disease. In addition, CEEs significantly and potently protected neurons against toxic insults associated with Alzheimer's disease. Because CEEs are the estrogen replacement therapy of the Women's Health Initiative, results of the current study could provide cellular mechanisms for effects of CEEs on cognitive function and risk of Alzheimer's disease derived from this prospective clinical trial.

Alzheimer Disease↗
PubMed2000

Effect of Salmonella typhi wild type and O-antigen mutants on human natural killer cell activity.

We investigated the effect of glutaraldehyde-fixed Salmonella typhi Ty2 (Vi(-)) wild-type (World Health Organization's vaccine strain) and mutant strains MEI028 (rough, O-antigen(-)) and MEI012 [smooth (O-antigen(+)95%), immunomagnetically isolated NK cell preparations. Incubation of PBMC with each and every one of the S. typhi strains studied consistently and significantly, increased this cellular immune function, as well as the supernatant level of the various cytokines tested e.g. IFN-gamma, TNF-alpha, IL-10 and IL-12 (ELISA). In similar experiments, a significant increase in the cytolytic activity of HPNK cells was elicited by S. typhi Ty2 but not by mutant strain MEI028; neither of the cytokines assayed (IFN-gamma and TNF-alpha) was detected in the supernatant. Our results suggest that S. typhi O-antigen plays an essential role in a mechanism resulting in the direct activation of NK cell activity in HPNK cell preparations. However, the relative quantitative significance of this antigen in the direct stimulation of NK cell cytotoxicity expression in PBMC samples is less clear, as it appears that in this case bacterial-induced monocyte-released cytokines plays a most important role. Incubation with S. typhi Ty2 or MEI028 elicited significant expression of CD69, an early marker of NK cell activation, in PBMC but not in HPNK cell samples (flow cytometry); in similar experiments, the expression of CD16/56 and activation marker CD25 remained essentially unchanged.

Adult↗
PubMed2000

Human antibody response to a 56-kDa purified excretory/secretory product of Dirofilaria immitis.

Canine dirofilariasis is widespread in urban areas of central and northern Colombia. Previously we detected specific antibodies against complex antigens from Dirofilaria immitis adult worms in individuals from an isolated Tikuna Indian community in the Colombian Amazon. In this study a 56 kDa polypeptide from the adult D. immitis excretory/secretory (E/S) products is identified by Western blot, isolated by elution from polyacrilamide gels and applied in an ELISA-based test for the detection of specific IgG. Eleven of 74 serum samples analysed were positive by ELISADi56. Positive individuals came from five different areas of Colombia. The highest number of positives was found in the Amazon (4), followed by Bogotà (3). The physicians of the area must be alerted regarding the existence of human D. immitis infections and include dirofilariasis in the differential diagnosis of pulmonary nodules.

Animals↗