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Biomedical subjects

R Montero

Publications and source records attributed to R Montero.

At least 55 records · Page 3Linked to original sources
PubMed1992

Inorganic arsenic effects on human lymphocyte stimulation and proliferation.

Lymphocyte cultures from individuals exposed to high levels of hydroarsenicism showed a slower cell cycle kinetics than cultures from low-exposed individuals. Since this difference in proliferation could be due to chronic arsenic exposure, the in vitro effects of inorganic arsenic in human whole blood lymphocyte cultures were investigated. When lymphocytes were exposed to concentrations of arsenite and arsenate similar to those found in the blood of exposed subjects (10(-7), 10(-8) and 10(-9) M) during the last 24 h before harvesting, a dose-related inhibition of proliferation was observed. Cultures were also treated with 10(-9) M of arsenite and arsenate for 2, 6 and 24 h at the beginning of the cultures in the presence or absence of phytohemagglutinin (PHA). Inhibition of stimulation and proliferation was directly related to the length of treatment. The results show that, at the concentrations tested, arsenite and arsenate impair lymphocyte stimulation and proliferation and confirm the fact that chronic arsenic exposure can affect the proliferation of whole blood lymphocytes.

Adult↗
PubMed1991

Determination of 6-thioguanine resistant lymphocytes in human blood by immunohistochemical antibromodeoxyuridine staining.

An immunohistochemical method for the determination of 6-thioguanine resistant (TGr) lymphocytes in human blood samples has been developed. The new technique is a modification of the autoradiographic assay and uses labelling of DNA synthesizing cells by bromodeoxyuridine (BrdU) instead of tritiated thymidine. The label is detected immunohistochemically by using a monoclonal antibody against BrdU in single-stranded DNA. Thawed cryopreserved isolated mononuclear cells are cultured with (TG cultures) and without (control cultures) TG for 40 h, the last 16 h with BrdU. The cells are harvested, fixed and put on microscopic slides; for the TG cultures, all material is used, while slides from the control culture are prepared at a dilution of 1:300. The immunohistochemical staining of the slides involves denaturation of DNA in formamide, incubation with anti-BrdU-DNA antibody, followed by a secondary antibody conjugated with peroxidase and staining with diaminobenzidine. Nuclei that have incorporated BrdU appear brown while all other material remains unstained. The number of all labelled nuclei is scored similarly in control and TG slides and the frequency of TGr lymphocytes is obtained by dividing the number of labelled nuclei in TG slides with that (multiplied by the dilution factor) in control slides. The anti-BrdU method will much simplify and speed up the microscopical evaluation of the TG variants and is very suitable for automation.

Bromodeoxyuridine↗
PubMed1990

6-Thioguanine-resistant T-lymphocyte autoradiographic assay. Determination of variation frequencies in individuals suspected of radiation exposure.

We used the autoradiographic assay to assess human in vivo somatic cell gene mutation at the hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus in T-lymphocytes. Cells able to incorporate tritiated thymidine in vitro in the presence of 6-thioguanine were enumerated in order to determine 6-thioguanine-resistance (TGr) variant frequencies in cryopreserved lymphocytes from 17 normal control individuals, from 3 persons suspected to have been exposed to 60Co in an accident in Cd. Juárez (Mexico), studied 24 months after the accident, and from 4 individuals who were in Kiev during the radiation accident in Chernobyl (U.S.S.R.); 2 of them were studied 1 month after the accident, and again 1 year after the first sampling, the other 2 were studied 13 months after the accident. The data obtained indicate that this assay may be useful in any laboratory of cytogenetics for human population monitoring and that its use following accidental exposure to ionizing radiation should be further evaluated.

Accidents↗
PubMed1990

Indirect continuous automatic determination of pharmaceuticals by atomic absorption spectroscopy.

The implementation of continuous separation techniques such as precipitation, liquid-liquid and solid-liquid extraction in FIA manifolds coupled on-line with an atomic absorption spectrometer for the determination of active components (sulphonamides, local anaesthetics, amphetamines, benzodiazepines, chloramphenicol and methadone) in pharmaceuticals and biological fluids is systematically described. The basic features of the analytical methodologies described (sensitivity, selectivity, precision and rapidity) are also discussed and critically compared.

Amphetamines↗
PubMed1986

Susceptibility to genotoxic effects of niclosamide in human peripheral lymphocytes exposed in vitro and in vivo.

Niclosamide added in 2-h pulses to lymphocyte cultures induced a small clastogenic effect in one blood donor, while in two other blood donors it inhibited mitosis. In the presence of the 'S9' metabolic activation system, the antihelminthic drug exhibited a dose-related increase in clastogenicity in 2 of 4 blood samples. A weak dose-related increase in S.C.E. was observed only in the lymphocytes from one of these blood samples. From 5 patients treated with niclosamide, 3 showed an increase in chromosomal aberrations after treatment; in none of them was an induction of S.C.E. observed. These results suggest differences in lymphocyte susceptibility to the genotoxic effects of therapeutic drugs and also underline the need for evaluating chromosomal aberrations as well as SCE in any study of genotoxic substances.

Adult↗
PubMed1986

Imipenem in the treatment of severe bacterial infections in seriously ill patients.

A multicentre, non-comparative study was performed to evaluate the clinical efficacy and safety of imipenem/cilastatin given iv to 53 seriously ill patients with severe bacterial infections, including 16 episodes of UTI, 12 pleuropulmonary, eight intra-abdominal, seven osteoarticular, and two soft tissue infections, three episodes of catheter related sepsis, two primary bacteraemias, one case of endocarditis, one of endophthalmitis, and one of disseminated gonococcal infection. Twenty-five patients were bacteraemic. The overall rate of clinical response was 94% of treated episodes; three cases failed to respond. Adverse reactions were mild and comparable with those reported with other beta-lactams. No patient had clinical superinfection; colonization occurred in seven patients. Imipenem is effective and safe as a single drug therapy for a wide range of infections in seriously ill patients.

Adolescent↗
PubMed1975

Surgical stabilization of traumatic flail chest.

Since 1970 we have stabilized the ribs to correct paradoxical movement of the chest wall in chest injuries, using an original technique, in order to avoid as far as possible the need for long-term chest wall stabilization by intermittent positive pressure respiration (IPPR). The technical details of surgical stabilization are described, and the different types of stainless steel struts are shown. Type I was originally used either as an intramedullary nail or as an external brace. Types II and III were designed for external fixation of the strut to the rib. Treatment of 29 patients with severe flail chest, classified into four groups is shown: group I was treated by IPPR, group II by IPPR plus surgical stabilization, group III by surgical stabilization only, and group IV by surgical stabilization after exploratory thoracotomy. The clinical results are discussed. We conclude that surgical stabilization of the paradoxial movement of the chest wall can avoid the use of the respirator or at least reduce the interval of IPPR to a short period during the initial recovery from trauma. Using type III struts, we have obtained stabilization of the flail chest in all cases even in patients with severe anterior paradoxical movement. The patients' tolerance of surgical stainless steel struts was good.

Humans↗
PubMed1970

A field on Che.

Explore the source record for details and available documents.

Argentina↗
PubMedDate not supplied

Lymphocyte proliferation kinetics and genotoxic findings in a pilot study on individuals chronically exposed to arsenic in Mexico.

In the search for early biological markers to detect genetic damage, a pilot study on a hydroarsenicism-exposed group was designed. Blood and urine samples were taken from 11 individuals chronically exposed and from 13 individuals with lower exposure to the metal. Lymphocyte cultures for cytogenetic studies and HGPRT assay were done with coded peripheral blood samples, while arsenic levels and the "rec assay" in B. subtilis were determined in urine samples. The highly exposed group excreted greater amounts of As, nevertheless the rec assay showed negative results. An interesting finding is that the cell-cycle kinetics exhibited a significant difference between the groups studied, the average generation time (AGT) was longer in the highly exposed group. The percentages of chromosomal aberrations and the frequencies of sister-chromatid exchanges were similar in both populations, although complex aberrations were more frequent in the highly exposed group, which also showed a higher average variation frequency in the HGPRT assay, but the 2 latter observations were not statistically significant. The lag in lymphocyte proliferation could mean an impairment of the immune response due to arsenic exposure.

Adult↗
PubMedDate not supplied

Lymphocyte replicating ability in individuals exposed to arsenic via drinking water.

A human monitoring study was carried out to explore the effect on lymphocyte proliferation of chronic exposure to arsenic (As) via drinking water. Blood and urine samples were taken from volunteers from a town where levels of As in the drinking water averaged 412 micrograms/l, and from a matched group of individuals, with similar socioeconomic status, that drank water with As average levels of 37.2 micrograms/l. Exposure was assessed by questionnaires and by determining the levels of As in urine and water samples. The evaluation of the peripheral blood lymphocyte proliferation was done at different culture times using labelling (LI), mitotic (MI) and replication indexes (RI) as endpoints. No significant differences were seen for either LI or MI, except for MI in 72 h cultures and in LI in males and females with skin lesions vs. those without lesions. Significant differences in RI were seen for exposed females but not for males. Correlations between LI and MI showed that progression from the initial S-to M-phase is altered in exposed individuals. Arsenic exposure as well as lead and mercury affect cellular immune response, making the endpoints of cell proliferation variables of interest in population monitoring study design, since they might provide information in health impairment due to exposure, which is important in risk assessment.

Adult↗
PubMedDate not supplied

[Cauda equina syndrome after intradural anesthesia with bupivacaine].

A 70-year-old man developed pain and functional weakness in the lower limbs with dysesthesia and urinary retention after subarachnoid anesthesia with 0.5% hyperbaric bupivacaine. Neurological and electrophysiological tests and follow-up, as well as diagnostic images (CAT and MR), ruled out spinal cord lesions. The diagnosis was cauda equina syndrome. Cauda equina syndrome is a neurological complication of subarachnoid anesthesia. Associated with use of microcatheters for continuous subarachnoid anesthesia and 5% hyperbaric lidocaine, cauda equina syndrome is rare after a single injection of bupivacaine. Although the pathogenesis of cauda equina syndrome is poorly understood, there is agreement on the neurotoxicity of local anesthetics, particularly of 5% hyperbaric lidocaine.

Aged↗
PubMedDate not supplied

[Lung transplantation for pulmonary fibrosis: perioperative morbidity and mortality].

Lung transplantation has become a valid therapeutic option for patients with pulmonary fibrosis in terminal stage, and the number of such interventions has increased exponentially in recent years. We undertook a retrospective study of 46 pulmonary fibrosis patients who received lung transplants from 1992 through 2002 with the aim of describing the most common intra- and early postoperative complications in the recovery unit. We also aimed to analyze the impact of each complication on mortality during the study period. The most frequent complications during surgery were reperfusion syndrome (47.5%), hemodynamic instability (41%), arrhythmias (23.9%), and pulmonary hypertension (15%), with exitus secondary to reperfusion syndrome. The most common postoperative complications were infection (56.5%), reimplantation response (45.7%), and kidney failure (19.6%). Overall mortality during the study period was 23.9%. The following complications were statistically significant in the univariate analysis of the relation with mortality: reperfusion syndrome (p=0.039), reimplantation response (p=0.039), kidney failure (p=0.013), rejection (p=0.016), and sepsis (p<0.001). The only complication that remained significant in the multivariate analysis was sepsis (p<0.001). In spite of the considerable progress made, intra- and postoperative complications continue to be a real threat for the transplanted lung patient. Sepsis was the strongest predictor of poor prognosis in the early recovery period.

Female↗
PubMedDate not supplied

[Application of continuous positive pressure to the uppermost lung in patients ventilated through a single lung].

We have studied the oxygenation process in a series of 20 patients who underwent thoracic surgery and were ventilated through a single lung. There were 19 men and one woman with a mean age (+/- SD) of 63 +/- 10.5 years, a mean height of 166 +/- 37.9 cm and a mean weight of 67 +/- 14.1 kg. Premedication and anesthesia were comparable among all patients. Endotracheal intubation was performed with a double lumen Robersthaw cannula. After anesthetic induction the radial and pulmonary arteries were catheterized to obtain samples for gasometric investigation in arterial and venous mixed blood before and after exclusion of one lung with continuous positive pressure (CPAP). Gasometric analysis was also performed during the immediate postoperative period. All patients were ventilated with 100% oxygen concentration 20 min before blood sampling in order to remove the alveolar nitrogen. During single lung ventilation and during application of CPAP (5 cm H20) to the upright sided lung we observed a 50% increase in arterial p02 (Pa02) (p less than 0.001) without any change in mean alveolar p02 (PA02). There was also a 17% decrease in alveolo-arterial oxygen difference (D[A-a]02) (p less than 0.001) and a 16.6% reduction in the intrapulmonary shunt (Qs/Qt) (p less than 0.001). Improvement of oxygenation was attributed to a beneficial effect of CPAP applied to the upright sided lung while intermittent positive pressure was maintained in the recumbent lung.

Aged↗
PubMedDate not supplied

6-Thioguanine resistant T-lymphocyte determination as a possible indicator of human ionizing radiation exposure.

We used the autoradiographic assay to assess human in vivo somatic cell gene mutation at the hypoxanthine guanine phosphoribosyl transferase (hgprt) locus in T-lymphocytes. Cells able to incorporate tritiated thymidine in vitro in 6-thioguanine containing short-term cultures were enumerated in order to determine 6-thioguanine resistant (TGr) variant frequencies in cryopreserved lymphocytes from control individuals and 3 persons suspected of 60Co exposure from an accident in Cd. Juárez, México. The data indicate that the lymphocyte TGr variant frequency assay may be potentially usefull for human population monitoring following accidental exposures to ionizing radiation.

Accidents↗