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Biomedical subjects

R Montero

Publications and source records attributed to R Montero.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of three microtube column agglutination systems for antibody screening: DG Gel, DiaMed-ID and Ortho BioVue.

The aims of the present study were to evaluate the estimated diagnostic accuracy of a new microtube column agglutination system (DG Gel, Diagnostic Grifols, Barcelona, Spain), to analyse the antibody reactivity and to compare the data with the two well-established DiaMed-ID and Ortho BioVue systems. We collected 3024 consecutive samples from blood donors, transfusion recipients and pregnant women, and 100 samples containing antibodies of known specificity. All these samples were tested in parallel by the three microtube agglutination systems. The estimated sensitivity was 100% for DG Gel and Ortho BioVue and 97.58% for DiaMed-ID. The estimated specificity was 99.93% for Ortho BioVue and 100% for DiaMed-ID and DG Gel. The score mean and range of the antibody titration of DG Gel, DiaMed-ID and Ortho BioVue were 34.31 (5-119), 30.3 (3-121) and 37.38 (3-112), respectively. All three column agglutination systems work well showing a high estimated diagnostic accuracy.

Agglutination Tests↗
PubMed2005

Spontaneous collapse of the tibial plateau: radiological staging.

OBJECTIVE: This paper proposes a radiological staging system for necrosis of the tibial plateau, similar to those already developed for the hip and the medial femoral condyle. DESIGN AND PATIENTS: We retrospectively studied the clinical case histories and radiographic findings of 14 patients (15 affected knees) with histologically proven osteonecrosis of the tibial plateau. RESULTS: Stage I was marked by normal radiograph, but increased uptake in bone scan and subchondral areas of abnormal marrow signal intensity in magnetic resonance imaging (MRI), as reported in other osteonecrosis sites. Stage II was characterised by cystic and sclerotic changes, and stage III fracture of the medial rim of the medial tibial plateau and tibial plateau collapse were present. Stage IV was marked by joint narrowing. These changes appeared earlier and were more pronounced when there was genu varum/valgum or involvement of the lateral tibial plateau. CONCLUSIONS: The radiological evolution of the disease appears to follow a four-stage course over a period of roughly one year from the onset of symptoms.

Aged↗
PubMed2005

Muscle coenzyme Q10 concentrations in patients with probable and definite diagnosis of respiratory chain disorders.

Coenzyme Q(10) (CoQ) deficiency syndrome is a disorder of unknown ethiology that may cause different forms of mitochondrial encephalomyopathy. In the present study our aim was to analyse CoQ concentration and mitochondrial respiratory chain (MRC) enzyme activities in muscle biopsies of patients with clinical suspicion and/or biochemical-molecular diagnosis of a mitochondrial disorder. We studied 36 patients classified into 3 groups: 1) 14 patients without a definitive diagnosis of mitochondrial disease, 2) 13 patients with decreased CI + III and II + III activities of the MRC, and 3) 9 patients with definitive diagnosis of mitochondrial disease. Only 1 of the 14 patients of group 1 showed slightly reduced CoQ values in muscle. Six of the 13 patients from group 2 showed partial CoQ deficiency in muscle and 1 of the 9 cases from group 3 presented a slight CoQ deficiency. Significantly positive correlation was observed between CI + III and CII + III activities with CoQ concentrations in the 36 muscle homogenates from patients (r = 0.555; p = 0.001; and r = 0.460; p = 0.005, respectively). In conclusion, measurement of MRC enzyme activities is a useful tool for the detection of CoQ deficiency, which should be confirmed by CoQ quantification.

Adolescent↗
PubMed2004

[General anesthesia by infusion of remifentanil for debridement and grafting of large burns in 3 pediatric patients].

Three 13-year-olds with burns on 30%, 70%, and 75% of their body surface areas and with related respiratory tract lesions underwent multiple surgical interventions for debridement, graft placement, and topical treatments. Balanced general anesthesia was provided with sevoflurane and an infusion of remifentanil and cisatracurium. Each patient underwent 41 procedures over a period of 6 months. All interventions were carried out without complications other than the difficulty of establishing an access to veins and monitoring because of the scarcity of intact surfaces. Remifentanil is an effective analgesic for meeting the needs of patients with severe burns. The combination of remifentanil, sevoflurane, and cisatracurium provides good hemodynamic stability and is very appropriate for patients who must undergo a large number of surgical interventions.

Adolescent↗
PubMed2002

[Lung transplantation in patients in mechanical ventilation before transplantation].

Mechanical ventilation before lung transplantation has been identified as a risk factor for early death after surgery. However, several studies have reported patient series in which ventilation assistance was given preoperatively without increasing the rates of postoperative complications and death, apart from increasing time of postoperative intubation. The present retrospective analysis of the postoperative course of patients who had been mechanically ventilated before transplantation encompasses a period of 5 years in our hospital. Eight transplants (7 double- and 1 single-lung procedures) were performed. Six patients (75%) required extracorporeal oxygenation during surgery. Three patients (37.5%) died within 30 days of receiving the transplanted lung. The mean time of intubation after the operation was 10.3 days and the mean stay in the postoperative recovery and intensive care unit was 27.5 days. The most common postoperative complications were respiratory colonization (100%), with infection in 3 patients, and reimplantation injury (50%). Pretransplant mechanical ventilation was associated with high risk in the patient series we report; however, the survival rate observed suggest that such patients should be considered acceptable candidates to receive grafts if indicated.

Adolescent↗
PubMed2001

[Refractory hypotension sustained during general anesthesia due to chronic treatment with angiotensin-converting enzyme inhibitors].

Perioperative management of angiotensin-converting enzyme inhibitors (ACEI) is controversial because of associated hypertensive episodes during induction and maintenance of anesthesia. A 71-year-old woman with a non-functioning thyroid node was scheduled for thyroid lobectomy. Her medical history included high blood pressure and she was being chronically treated with ACEI, which were taken until the morning of surgery. After induction of anesthesia, arterial hypotension refractory to crystalloid therapy developed and worsened in spite of administration of a gelatin-type colloid (Gelafundina). The patient did not respond to ephedrine or dopamine and required stabilization with adrenalin in continuous perfusion for 12 hours. Later evolution was satisfactory and recovery took place without sequelae. We discuss the anesthetic implications of chronic ACEI treatment and possible hemodynamic repercussions of associated administration with gelatin-type solutions or human albumin.

Aged↗
PubMed2000

Dietary habits and cardiovascular risk in the Spanish population: the DRECE study (I). Diet and Cardiovascular Events Risk in Spain.

BACKGROUNDS/AIMS: To investigate dietary habits and their evolution with regard to cardiovascular risk status in Spain. METHODS: Cross-sectional study performed in two phases in 1991 and 1996 in 43 primary care clinics. One thousand and two hundred people classified as 'with cardiovascular risk' and 600 'without risk' were studied. Each participant answered a food frequency questionnaire. RESULTS: The risk group did not change oil, cereals and dairy products consumption, decreased egg, legume and meat, and increased fish, fruits and vegetables intake. The control group differed in increasing dairy products and not decreasing eggs and vegetables consumption. A small decrease in energy intake happened, from 11,315. 1 to 10,941.5 kJ in the risk group (p < 0.05). Carbohydrates intake showed a not statistically significant falling trend from 41.3 to 40.6% in people at risk and 41.8 to 40.7% in those without risk. Protein intake increased in both groups up to 16.5% and fat consumption kept at around 42.9% in both groups. The decrease in saturated fat and increase in polyunsaturated fat were statistically significant in people at risk (p = 0.000). High cholesterol intakes were found. CONCLUSION: People with cardiovascular problems changed their dietary habits in a 'healthier' way than people without risk.

Adolescent↗
PubMed2000

Dietary habits and cardiovascular risk in the Spanish population: the DRECE study (II) micronutrient intake. Dieta y Riesgo de Enfermedades Cardiovasculares en España.

OBJECTIVE: To evaluate the dietary micronutrient intake in the adult Spanish population participating in the DRECE study. METHODS: The cross-sectional study was performed in two stages in 1991 and 1996 in 43 primary care clinics. One thousand two hundred people 'with cardiovascular risk' and 600 'without risk' answered a food frequency questionnaire. RESULTS: Significant increases in vitamin C, retinol, lycopenes, beta-cryptoxanthin and vitamin E intakes were found. Vitamin A, alpha-carotenoid and lutein intakes decreased. Vitamin B(12), B(6) and folic acid intakes increased in people with cardiovascular risk, whereas only the last two increased in the control group. Nearly 100% of the people consumed the recommended dietary allowances for vitamins B(12) and B(6) and >70% for folic acid. Calcium, iron, and zinc intake increased in both groups, but magnesium and selenium intake increased only in people at risk. Vitamin A, B(1) and zinc intakes have decreased, and >50% of the people do not consume the recommended dietary allowance. CONCLUSION: Antioxidant vitamins and vitamin B(12), B(6) and folic acid intakes seem to be adequate in the adult Spanish population, no significant differences appear regarding their cardiovascular risk status. Vitamin A, B(1) and zinc intakes are not appropriate.

Adolescent↗
PubMed2000

[Lesion caused by ischemia-reperfusion in lung transplantation].

OBJECTIVES: To assess the existence or not of a relation between the characteristics of lung donor and/or recipient and the development of ischemia-reperfusion injury (IRI). We also review the latest experimental findings on the biophysical conditions pf graft preservation. PATIENTS AND METHOD: A retrospective study of 74 lung transplants performed in our hospital from 1993 to 1998. Donor and recipient screening and anesthetic and surgical techniques were performed following established protocols. Various degrees of IRI were determined according to hemodynamic and gasometric criteria. We analyzed the statistical relation between donor and recipient variables and IRI. Statistical significance was set at p < 0.05. RESULTS: The incidence of IRI was 70.2% (52 cases), with 12 cases categorized as mild, 22 as moderate and 18 as severe. IRI was significantly related only to the start of extracorporeal circulation. CONCLUSIONS: The development of IRI in lung transplantation is linked to such donor and/or recipient characteristics as the biophysical conditions of graft preservation. At present, greater prevention of this type of early dysfunction of the lung graft requires not only use of adequate screening criteria for donors and receivers but also adequate measures for graft preservation with the use of drugs and handling that have been shown to be effective.

Adolescent↗
PubMed2000

[Lung transplantation and hemophilia. Preoperative considerations].

Lung transplantation is indicated in certain patients with terminal pulmonary disease. We report a case in which a single lung (left) was transplanted to a 16-year-old girl with hemophilia B; she also suffered idiopathic pulmonary fibrosis and had a history of malnutrition, osteoporosis, severe scoliosis, hepatitis C positivity and recurrent bilateral pneumothorax. Treatment with pure factor IX was started the moment the donor lung was available and was continued for 37 days after surgery. Plasma levels of factor IX were kept at 100% during surgery and in the early postoperative period, and over 40% after that time. Correct hemostasis was thus achieved throughout the procedure, with no need for blood products. Patient outcome was satisfactory. The stay in the intensive care recovery ward was 17 days and discharge was 40 days after transplantation. We discuss aspects of hemophilia and lung transplantation, and the influence on malnutrition, chronic steroid treatment and osteoporosis.

Adolescent↗
PubMed1999

Induced expression of CYP2A5 in inflamed trematode-infested mouse liver.

Trematode infections have long been associated with specific types of cancer. We investigated the ability of the liver fluke Fasciola hepatica to alter host enzymes in a manner that might provide insight into the phenomenon of biologically associated cancers. Our data demonstrate an increased activity of the CYP2A5 isozyme in male mouse liver infected with F.hepatica. Induction of this enzyme was further assessed immunohistochemically. The infection affected CYP2A5 distribution in hepatic tissue. Inflammation and proliferation in liver tissue were observed at the same time that CYP2A5 activity increased. This enzyme is known to participate in the metabolism of several carcinogens which are common contaminants in environments of developing countries where parasitic infections may be prevalent.

Animals↗
PubMed1999

[Paraplegia after surgery for aneurysm of the descending thoracic aorta].

Postoperative paraplegia caused by ischemic injury of the spinal cord is the most disabling complication of thoracoabdominal surgery, particularly when repair of the descending thoracic aorta is involved. We describe the case of a 59-year-old man who underwent emergency surgery for placement of a Dacron prosthesis to repair a ruptured descending thoracic aorta aneurysm, using an aortic cross-clamping technique plus aortic-femoral partial bypass with normothermia and an ischemic time of 165 minutes. The early postoperative course included complete spinal syndrome with motor and sensory loss below T5, with consequent respiratory insufficiency of neuromuscular origin. The result was a difficult postoperative course including prolonged mechanical ventilation and recurrent respiratory infections. Possible causes include prolonged time of ischemia, inadequate monitoring of distal aortic pressure and inappropriate surgical technique related to the absence of angiographic data on spinal vascularization. We conclude that ischemic time should be kept to under 30 minutes whenever possible. In cases of prolonged ischemia, bypass techniques with outflow to the distal aortic segment are more effective whenever mean blood pressure at this point rises to 60 mmHg or more. Vasodilator use should be reserved for cases of severe arterial hypertension and left ventricular failure and/or life-threatening increases in aortic wall stress even if not leading to dangerous decreases in distal aortic pressure. Finally, angiographic study to obtain anatomical details of spinal blood flow is advisable.

Aortic Aneurysm, Thoracic↗
PubMed1998

Enhanced liver cell mutations in trematode-infected Big Blue transgenic mice.

Parasite infections in humans have long been associated with specific types of cancers. Schistosoma hematobium is a known inducer of urinary bladder cancer, Helicobacter pylori is a gastric carcinogen, and hepatitis B virus and Opisthorchis viverrini are causative agents of liver cell cancers. Another liver fluke, Fasciola hepatica, has also been identified as a neoplastic risk agent, primarily in animals. We used F. hepatica as a model agent to determine if the presence of an aggressive liver fluke could induce mutagenic events in mammalian tissue. Using the Big Blue(R) transgenic mouse assay, we found a two-fold increase in lacI mutations in cells harvested from mice harboring F. hepatica worms when compared to uninfected control animals. These data indicate that biological infections can cause increased genetic damage in surrounding host tissue.

Animals↗
PubMed1997

Altered profile of urinary arsenic metabolites in adults with chronic arsenicism. A pilot study.

Relationships between alterations in the profile of urinary arsenic (As) species and the presence of cutaneous signs of arsenicism were studied in Region Lagunera, Mexico. The use of urinary concentrations of putative substrates and products of the As metabolism pathway, as indicators of metabolic efficiency is also discussed. Arsenic was determined by hydride generation atomic absorption spectrophotometry and separation of As species was performed by ion exchange chromatography. The exposed group had an average of 0.408 mg As/l of total As (TAs) in their drinking water, whereas "control' individuals had 0.031 mg/l. Urinary concentrations of arsenic species and TAs were 20 to 95 times higher in the exposed group. Significant increases in the relative proportions of inorganic arsenic (Asi) and monomethylarsonic acid (MMA), accompanied by decreases of dimethylarsinic acid (DMA) were also found in exposed individuals. Therefore, significant decreases in the value of the MMA/Asi, DMA/MMA and DMA/ Asi ratios were observed, suggesting a decreased As methylating ability. Exposed individuals bearing cutaneous signs had a significantly longer time of exposure, higher urinary concentrations and proportions of MMA and MMA/Asi values, and significantly lower DMA/ MMA than exposed individuals without cutaneous signs. Further research is needed to identify better parameters for assessing the efficiency of As metabolism in chronically exposed populations and to confirm the potential relationship between metabolic alterations and overt signs of As toxicity.

Adult↗
PubMed1997

Cytogenetic effects in human exposure to arsenic.

The cytogenetic effects of arsenic exposure were studied among rural populations that live in the same geographical area and have similar socioeconomic status, but different degree of exposure to inorganic arsenic (As) via drinking water. A group of inhabitants of Santa Ana (408.17 micrograms/l of As in drinking water) were considered the exposed individuals and a group of inhabitants of Nazareno (29.88 micrograms/l) were considered as controls. Blood and urine samples were obtained from volunteers. Past and current exposure, health, and nutritional status as well as the presence of arsenic skin lesions were ascertained in study participants through questionnaires and physical examination. The frequencies and types of chromosomal aberrations in first-division metaphases were studied in whole blood lymphocyte cultures while the presence of micronuclei (MN) was studied in exfoliated epithelial cells obtained from the oral mucosa and from urine samples. Total arsenic (TAs) content, and the relative proportions of inorganic arsenic (IAs), and the metabolites monomethylarsonic (MMA) and dimethylarsinic (DMA) acid were determined in urine samples. Exposed individuals showed a significant increase in the frequency of chromatid and isochromatid deletions in lymphocytes and of MN in oral and urinary epithelial cells. Males were more affected than females, and a higher number of micronucleated oral cells were found among those individuals with skin lesions. The type of cytogenetic damage observed gives evidence of arsenic as a clastogenic/aneugenic carcinogen.

Adult↗
PubMed1997

Genotoxic activity of praziquantel.

Praziquantel is a synthetic drug with a remarkable activity against parasites, particularly treamatodes and cestodes. Initial genotoxicity tests used a spectrum of endpoints including tests in bacteria, yeasts, mammalian cells and Drosophila and each one gave negative results. Effects on reproductive cells of mice were negative as well. However, host mediated studies in mice and humans were contradictory and a comutagenic effect with several mutagens and carcinogens was found. Later studies, including monitoring in humans and pigs have shown that Praziquantel induces a greater frequency of hyperploid lymphocytes as well as structural chromosomal aberrations, but not in all the individuals treated. In vitro studies have demonstrated that Praziquantel can induce micronuclei in syrian hamster embryonic (SHE) cells and in lymphocytes of some individuals. The same was found about structural chromosomal aberrations. Fetal death and fetal resorption were found when Praziquantel was administered in high doses to pregnant rats between the 6th and 10th day of gestation. Due to its efficiency as a parasiticide, Praziquantel is in use in Latin-American, Asiatic, African and East-European countries where infections by trematodes and cestodes are frequent. However, the extensive use of Praziquantel in multiple reinfections, in non-infected and non-diagnosed individuals for prevention, in higher doses or repeated doses for cysticercosis treatment and in individuals exposed to environmental mutagens, in conjunction with new findings about its metabolism and genotoxic properties, make it necessary to further evaluate the potential of this drug not only to be mutagenic per se, but to contribute in the development of neoplasm.

Animals↗