Biomedical subjects

I Sierra

Publications and source records attributed to I Sierra.

At least 19 recordsLinked to original sources

PubMed2005

Preparation of 2-mercaptobenzothiazole-derivatized mesoporous silica and removal of Hg(ii) from aqueous solution.

Mesoporous silicas (SBA-15 and MCM-41) have been functionalized by two different methods. Using the heterogeneous route the silylating agent, 3-chloropropyltriethoxysilane, was initially immobilized onto the mesoporous silica surface to give the chlorinated mesoporous silica Cl-SBA-15 or Cl-MCM-41. In a second reaction a multifunctionalized N,S donor compound (2-mercaptobenzothiazol) was incorporated to obtain the functionalized silicas denoted as MBT-SBA-15-Het and MBT-MCM-41-Het. Using the homogeneous route, the functionalization was achieved via the one step reaction of the mesoporous silica with an organic ligand containing the chelating functions, to give the modified mesoporous silicas denoted as MBT-SBA-15-Hom or MBT-MCM-41-Hom. The functionalized mesoporous silicas were employed as adsorbents for the regeneration of aqueous solutions at pH 6 contaminated with Hg(ii) at room temperature. Results obtained indicate that mercury adsorption was higher in the mesoporus silicas prepared by the homogeneous method, and the maximum adsorption value (0.24 +/- 0.02 mmol Hg(ii) g(-1)) was obtained for MBT-SBA-15-Hom. The chemically stability in acid medium of the functionalized silicas, possibility its regeneration washing with concentrate HCl, resulting in the reuse of the adsorbent material for several cycles.

Adsorption↗

PubMed2005

Phylogenetic relationships among Spanish goats breeds.

We partially sequenced the mitochondrial hypervariable region 1 (HVR1) in 60 goats belonging to six Spanish breeds. The analysis of these and previously published sequences reveals a weak phylogeographical structure in the Iberian Peninsula breeds. Individuals from a single breed did not group into a single cluster. Furthermore, individuals from different breeds often shared single phylogenetic tree branches after UPGMA analysis. This could reflect the non-existence of breed isolation because of traditional seasonal pastoralism and annual long-distance migrations. Three goats belonging to the C maternal lineage were found, demonstrating a wider than previously thought distribution for this lineage.

Animals↗

PubMed2003

Guidance on individual monitoring programmes for radioisotopic techniques in molecular and cellular biology.

The radioisotope techniques used in molecular and cellular biology involve external and internal irradiation risk. The personal dosemeter may be a reasonable indicator for external irradiation. However, it is necessary to control the possible internal contamination associated with the development of these techniques. The aim of this project is to analyse the most usual techniques and to establish programmes of internal monitoring for specific radionuclides (32P, 35S, 14C, 3H, 125I and 131I). To elaborate these programmes it was necessary to analyse the radioisotope techniques. Two models have been applied (NRPB and IAEA) to the more significant techniques, according to the physical and chemical nature of the radionuclides, their potential importance in occupational exposure and the possible injury to the genetic material of the cell. The results allowed the identification of the techniques with possible risk of internal contamination. It was necessary to identify groups of workers that require individual monitoring. The risk groups have been established among the professionals exposed, according to different parameters: the general characteristics of receptor, the radionuclides used (the same user can work with one, two or three radionuclides at the same time) and the results of the models applied. Also a control group was established. The study of possible intakes in these groups has been made by urinalysis and whole-body counter. The theoretical results are coherent with the experimental results. They have allowed guidance to individual monitoring to be proposed. Basically, the document shows: (1) the analysis of the radiosotopic techniques, taking into account the special containment equipment; (2) the establishment of the need of individual monitoring; and (3) the required frequency of measurements in a routine programme.

Cell Biology↗

PubMed2001

Critical points in the transport of cattle to slaughter in Spain that may compromise the animals' welfare.

The welfare of cattle depends greatly on the attitudes and training of stockpersons and on the availability of appropriate facilities. Much has been learned about stress during transport, but less attention has been paid to identifying and correcting critical points, partly because they vary widely both nationally and internationally. A survey of cattle transport in Spain was made in an effort to determine which parts of the process most compromised the animals' welfare. Data were collected on the methods and facilities for loading and unloading, transport times, types of vehicle and slaughterhouse practices. Loading facilities were adequate and loading times generally short but some farms continued to use an electric goad and weather-proofing was generally poor. The average journey time within Spain was three-and-a-half hours, but many trips were made abroad (especially to Italy), few drivers received specific training courses and the types and quality of vehicles varied widely. The average unloading time was very short but the animals were not always inspected for injuries or dirtiness. Lairage times were normally more than eight hours but few slaughterhouses had air-conditioning equipment to prevent excessive heat or dehydration. Almost all stockpersons avoided either regrouping animals or housing or transporting animals at high densities.

Abattoirs↗

PubMed2001

Determination by capillary electrophoresis of total and available niacin in different development stage of raw and processed legumes: comparison with high-performance liquid chromatography.

The available and total niacin evolution during maturation of yellow pea lupine (Lupinus luteus L., cv. Juno), pea (Pisum sativum L., cv. Ergo), faba bean (Vicia faba sp. minor Harz, cv. Tibo) and in germinated and high-pressure heated peas (Pisum sativum L., cv. Esla) have been determined by capillary electrophoresis (CE). The results have been compared with those obtained by high-performance liquid chromatography (HPLC). The values obtained by CE were similar to those obtained by HPLC. Maturation of seeds significantly reduced the available and total niacin content in legumes. The available/total niacin ratio during seed maturation depends on the type of legume. In faba beans and peas, a reduction was observed which was more pronounced in the case of peas. For lupine seeds, the ripening produced an increase (34%) in the available/total niacin ratio 50 days after flowering (DAF). Pea germination produced an overall increase in available and total niacin content although the available/total niacin ratio decreased. High pressure heating of pea yielded an increase in the available niacin content and available/total niacin ratio but the total niacin content did not change.

Chromatography, High Pressure Liquid↗

PubMed2001

Determination of iron and molybdenum in a dietetic preparation by flame AAS after dry ashing.

Methods for the determination of iron and molybdenum in a dietetic pharmaceutical preparation by flame atomic absorption spectrometry (FAAS) after dry ashing at 600 degrees C have been validated. Linearity, precision, accuracy, detection and quantification limits, specificity and robustness have been determined. Linearity of response was verified for concentrations ranging from 0.50 to 4.00 mg l(-1) of iron and 1.00 to 6.00 mg l(-1) of molybdenum. Precision of the methods, performed under conditions of repeatability and reproducibility, gave relative standard deviations of 0.4 and 1.1%, respectively, for the iron determination and of 1.0 and 6.5%, respectively, for the molybdenum determination. Mean recoveries determined after spiking dietetic preparation placebos ranged from 97.1 to 102.6% for iron and 95.2 to 102.9% for molybdenum. The limit of detection for iron was 126 microg g(-1) and for molybdenum 129 microg l(-1). Quantification limits were 420 and 433microg l(-1) for iron and molybdenum, respectively. No interference in the iron and molybdenum determination due to other components present in the dietetic capsules was found. Day-to-day and analyst-to-analyst variability was less than 1.1% for iron and 4.5% for molybdenum. Results show the suitability of the method for measurement of iron and molybdenum in a complex matrix sample such as a dietetic pharmaceutical preparation.

Dietetics↗

PubMed2001

A validated flame AAS method for determining magnesium in a multivitamin pharmaceutical preparation.

A rapid method for determining magnesium in a multivitamin pharmaceutical preparation has been validated. This element is analysed by flame atomic absorption spectrometry after dissolution of the sample in acid medium. Linearity, precision, accuracy and robustness of the method have been determined, and detection and quantification limits have been calculated. Linearity of response was verified for concentrations ranging from 0.05 to 0.40 mg x l(-1) of magnesium. Correlation coefficient of the calibration straight lines was always > or =0.9999. Repeatability of the method gave relative standard deviation (R.S.D.) of 0.6%. Reproducibility of the method calculated after analysis of samples by the same analyst in different days (day-to-day fluctuation) and by two different analysts in different days (analyst-to-analyst fluctuation) gave relative standard deviation of 1.1 and 1.6%, respectively. Mean recoveries of magnesium obtained after spiking sample placebos with increasing amounts of magnesium chloride ranged from 98.9 to 100.8%. Robustness of the method evaluated by changing different experimental conditions under which analyses were performed, gave relative standard deviation from 0.2 to 0.5%. Limits of detection and quantification were 3.8 and 7.0 microg of Mg per gram of sample, respectively. Results show the suitability of the method for direct measurement of magnesium in a water-soluble multivitamin pharmaceutical preparation.

Magnesium↗

PubMed2001

Nutritional evaluation of ethanol-extracted lentil flours.

Lentil flours were extracted with 80% ethanol at 25 and 50 degrees C for 1, 2, or 3 h. The various nitrogen fractions, soluble carbohydrates, three amino acids (Lys, His, and Tyr), available lysine, protein digestibility, and vitamins B(1) and B(2) were analyzed to evaluate the effect of extraction. Extraction resulted in an increase in the total nitrogen content of the extracted flours, with extraction temperature affecting the nature of the nitrogen (protein or nonprotein) content. There was also a large reduction in the oligosaccharides of the raffinose family, although the effect of temperature was appreciable only in the case of stachyose. There was hardly any effect on the concentrations of the amino acids analyzed or on protein digestibility; however, a positive correlation between protein digestibility and the available lysine was recorded in the samples. The vitamin B(1) and B(2) contents underwent variable decreases depending on extraction temperature.

Amino Acids↗

PubMed2001

Vitamin B1 and B6 retention in milk after continuous-flow microwave and conventional heating at high temperatures.

The effect of continuous-flow microwave treatment at high temperatures on the retention of vitamins B1 and B6 in raw milk with different fat content was evaluated. Results were compared with those obtained using a conventional system (tubular heat exchanger) with the same heating and cooling phases. Heat treatment of whole (3.4% fat) and skim (0.5% fat) milk at 90 degrees C produced no losses of vitamin B1 or vitamin B6 (pyridoxamine and pyridoxal). However, at 110 and 120 degrees C, while vitamin B1 content of milk remained constant, pyridoxamine increased (4 to 5% and 9 to 11%, respectively) and pyridoxal decreased (5 to 6% and 9 to 12%, respectively). Under the assayed conditions, no differences were observed between the content of these vitamins in conventionally and continuous-flow microwave-treated milk.

Animals↗

PubMed2001

Determination of lumbar muscular activity in helicopter pilots: a new approach.

BACKGROUND: Discomfort in the lumbar region is a frequent complaint of helicopter pilots. Two factors that helicopter crewmembers relate to back pain are exposure to vibration and poor posture during flight, because during flight the seat and controls force the pilot to adopt an asymmetric posture. Repeated exposure to these adverse flight conditions could cause pathological changes in the spine. The purpose of this study was to compare right and left sided lumbar muscular activity in helicopter pilots under real flight conditions, using surface electromyography (SEMG) to demonstrate the effects of asymmetrical posture on the musculoskeletal system. An attempt was also made to correlate lumbar muscular activity with environmental factors and such variables as type of flight, type of helicopter, duration of flight, age, physical fitness, and height. METHODS: Right- and left-sided lumbar electrical activity were measured using two-channel SEMG during 35 flights in 2 types of helicopter and a cockpit mock-up. RESULTS: There was a statistically significant increase in right-sided lumbar activity when related to the duration of flight. CONCLUSIONS: The data showed that when the pilot used the manual controls during flight, he did not maintain a symmetrical posture and contracted one side more than the other. We think the relationship between the greatest right-sided contraction and flight duration is due to maintaining an asymmetric posture over a long period. We also noted a tendency towards greater right lumbar musculature activity in older pilots.

Adult↗

PubMed1996

[Ataxia telangiectasia: review of 13 new cases].

We report the review of 13 patients who were diagnosed of ataxia telangiectasia before 6 years of age. All of them manifested cerebelous ataxia, oculocutaneus telangiectasias (11), sinopulmonary infections (9), dystonia (9), oculomotor apraxia (9) and Burkitt linfoma (1). We analyse the most common presentation of the disease in early stages and the complementary studies performed. The prompt diagnosis allow us a better control of infections, malignant process and finally the possibility of genetic counseling.

Adolescent↗

PubMed1992

Invasive maxillary aspergillosis after dental extraction. Case report and review of the literature.

Paranasal sinus aspergillosis has usually been considered a rare disease, but it is seen more frequently in both immunocompromised and immunocompetent persons. Invasion may reach the sinuses via the nose or from the mouth after dental procedures. Even though the infection is usually limited to one or more sinuses, it may in certain cases extend to vascular or intracranial structures with a fatal outcome. In these cases, aggressive treatment is justified. We report a case of maxillary sinus aspergillosis that developed after dental extraction. Attention should be given to this possibility even after an apparently uncomplicated dental extraction.

Adult↗

PubMed1992

Polymorphous low-grade adenocarcinoma of the oral cavity: a report of 14 cases.

The clinicopathologic characteristics of 14 new cases of low-grade polymorphous adenocarcinoma of the oral cavity are presented. Tumors were located in the palate in 10 cases, and in one case each in the base of the tongue, buccal mucosa, tonsil, and retromolar pad. Nine cases were previously diagnosed as other categories of benign and malignant tumors. The tumors were classified as terminal-duct and low-grade papillary adenocarcinomas. Three cases developed local recurrence and four cases had lymph nodes metastasis, two on admission and two during the course of the disease. Two of the local recurrences and all cases with metastasis were salvaged with further surgery with or without irradiation. Recurrence and metastasis occurred only with the terminal duct adenocarcinoma. There was no death related to the neoplasm, although one patient is living with advanced disease.

Adenocarcinoma↗

PubMed1991

Temporalis myofascial flap for maxillofacial reconstruction.

To date, the temporalis myofascial flap has been used only to a limited extent for reconstruction in the maxillofacial region. Experience gained with 26 temporalis flaps in reconstruction of tissue defects in the periorbital region, skull base, maxilla, and oral cavity is presented. Only one patient developed total necrosis of the flap; significant necrosis did not occur in any other patient. The anatomy of the flap and surgical technique are briefly presented.

Adult↗

PubMed1991

AIDS-related lymphoma of the oral cavity.

Six new cases of non-Hodgkin's lymphoma (NHL), primarily located in the oral cavity, in patients infected by the human immunodeficiency virus (HIV), are presented. They all had a voluminous fungous tumoral mass, that extended from the gingiva to the buccal vestibule or palate. All were intravenous drug abusers. The diagnosis of AIDS was known in one patient, 2 patients presented with AIDS-related complex symptomatology, and in 3 cases NHL was the first manifestation of the HIV infection. All presented advanced stages (IV). Histologically, all were considered high grade NHL. It is recommended to determine the HIV status in all young patients affected with oral NHL. All intraoral lesions in AIDS patients or in patients that belong to a risk group should have a biopsy to rule out NHL or any other manifestations of AIDS.

AIDS-Related Complex↗

PubMed1991

Acinic cell carcinoma of the salivary glands. A review of 20 new cases.

Twenty patients with acinic cell carcinoma of the salivary glands are presented. Seventeen tumours were located in the parotid and three in minor salivary glands, one being considered intraosseous. According to the growth patterns, they were classified as solid-acinar in 8 patients, microcystic in 5 patients, follicular in 3 patients and papillocystic in 4 patients. 9 cases were considered high grade malignant tumours and among the 11 well-differentiated, 2 suffered dedifferentiation in local recurrences. Local recurrence appeared in 9 cases. Three cases had nodal disease on admission while 5 developed this during the course of the disease. Distant metastasis appeared in 2 cases. Local recurrence and nodal disease correlated with the degree of differentiation and state of the margins in the surgical specimen. We recommend an aggressive surgical approach followed by postoperative radiotherapy for the undifferentiated tumours and extensive ones. For the limited and better differentiated, a more limited excision, such as total parotidectomy preserving the facial nerve is suggested.

Adult↗

PubMed1991

Maxillofacial malignant peripheral nerve sheath tumours.

The clinical and pathological features of 7 patients with MPNST in the maxillofacial area are reviewed. They occurred in five men and two women; ages ranged from seven to eighty years. The parotid area and infratemporal fossa were the commonest sites (two cases each), followed by the lower lip, cheek and central mandible (one case each). Two had the antecedent of an excised neurofibroma, one with von Recklinghausen's disease and radiotherapy, that had recurred many times. Pathological slides were revised. Immunohistochemistry with S-100 protein was positive in 6 of 7 cases; electron microscopy confirmed the diagnosis in 3 cases. None showed divergent differentiation. Surgical treatment was performed in all, with or without radiotherapy. Surgical margins were positive in five cases. Recurrence took place in six and was multiple in three. Surgical salvage of the local recurrences produced satisfactory results in 3 of the 6 cases. One patient developed lung metastasis.

Adolescent↗

PubMed1989

[Benign hemophagocytic syndrome. First confirmed case in Panama].

The authors present the clinical history of the first case of benign hemophagocytic syndrome diagnosed in Panama. The patient, a 4 year old girl, presented with fever, anemia, cervical lymphadenitis, hepatomegaly, lymphocytosis and histophagocytosis of red cells, lymphocytes, neutrophils and platelets. Spontaneous remission of the fever occurred sixty days after the onset of the disease. Although it was not possible to demonstrate serologically that the syndrome was due to acute toxoplasmosis, she was treated with sulfadiazine and pyrimethamine for fifteen days, on the 37th hospital day, and with clindamycin for ten days, consecutively. Remission occurred seventy days after the onset of fever. A second serological examination for toxoplasmosis (immunofluorescent antibodies) was positive in a titer of 1:2048 again, nine months after the first serology.

Child, Preschool↗