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Biomedical subjects

J M Fernandez

Publications and source records attributed to J M Fernandez.

At least 19 recordsLinked to original sources
PubMed2006

Antioxidant activity of Haematococcus pluvialis cells grown in continuous culture as a function of their carotenoid and fatty acid content.

The influence of culture conditions on the quality of Haematococcus pluvialis biomass is assessed. Continuously grown cells have been characterised with respect to their astaxanthin, fatty acid content, and antioxidant activity and compared with those of non-growing haematocysts. Moderate limitation of nitrate availability (1.7 mM) under continuous growth conditions favoured the production of reddish palmelloid cells whose extracts possessed antioxidant activity equivalent to that of haematocyst extracts, despite the lower astaxanthin content (0.6%d.wt.), which is compensated by a higher fatty acid level (7.6%d.wt.). Green cells produced under nitrate saturation conditions (>4.7 mM) exhibit only 40% antioxidant activity than palmelloid. In addition, the major fatty acid present in palmelloid cells was oleic acid (40%f.a.), whereas, in both green cells and haematocysts, the main fatty acids were myristic, palmitic, and oleic acid (20-30%f.a. each). Biomass extracts were fractionated and analysed. The antioxidant capacity was a function of both the carotenoid and the fatty acid profiles, the antioxidant capacity of astaxanthin diesters fraction being 60% higher than astaxanthin monoesters fraction and twice than free astaxanthin. In such a way, the evaluation of the quality of H. pluvialis biomass must take into account both variables. When considering the production of H. pluvialis biomass for human consumption, special attention should be paid to the one-step continuous system approach for the generation of cells rich in both astaxanthin and fatty acids, as they have high antioxidant activity but without thick hard cell wall.

Antioxidants↗
PubMed2006

Evaluation of risk of deterministic effects in fluoroscopically guided procedures.

A methodology for the evaluation of skin dose distribution and possible skin injuries on patients undergoing interventional procedures has been developed as part of the European DIMOND programme. Relevant dosimetric data from the procedures are recorded and other specific measurements for skin dose evaluation (slow films for therapy, radiochromic films, thermoluminescence dosemeters and optically stimulated luminescence dosemeters) have been carried out. For non-cardiac and for some cardiac procedures, dose-area product values of 200 and 300 Gy cm2 were proposed, respectively, as a trigger level for further detailed skin dose investigation and possible clinical follow-up. Results from a survey of 191 selected complex procedures are reported. Out of all the patients included in the trial, 16% received skin doses > or =1.5 Gy. No skin injuries were found in any of the patients followed.

Dose-Response Relationship, Radiation↗
PubMed2006

Patient dosimetry and image quality in digital radiology from online audit of the X-ray system.

The present work describes an online patient dosimetry and an image quality system in digital radiology. For the patient dosimetry audit, current mean values of entrance surface dose (ESD) were compared with local and national reference values (RVs) for the specific examination type evaluated. Mean values exceeding the RV trigger an alarm signal and then an evaluation of the technical parameters, operational practice and image quality was begun, using data available in the DICOM header to derive any abnormal settings or performance to obtain the image. The X-ray tube output for different kVp values is measured periodically, to allow for the automatic calculation of ESD. The system allows also for image audit, linking the dose imparted, the image quality and the alarm condition, if produced. Results and the benefits derived from this online quality control are discussed here.

Humans↗
PubMed2006

Influence of patient thickness and operation modes on occupational and patient radiation doses in interventional cardiology.

Patient and staff dose values in an interventional cardiology laboratory for different operational modes and several patient thicknesses (from 16 to 28 cm, simulated using polymethylmethacrylate) are presented. When increasing patient thicknesses and depending on fluoroscopy and cine modes, occupational doses can increase >30 times the baseline level. Scatter dose rates at the cardiologist's position with no radiation protective tools ranged from 1 to 14 mSv h(-1) for fluoroscopy, and from 10 to 47 mSv h(-1) during cine acquisition. Patient entrance surface air kerma rates increased by nearly 3 and staff dose rates by up to 2.6 when fluoroscopy was moved from the low to the high mode, for a typical 20 cm thickness. The respective increase factors were 6 and 4.2 when patient thickness rose from 16 to 28 cm, and by 10 and 8.3, when comparing cine acquisition with the low fluoroscopy mode. The knowledge of typical dose rates for each X-ray system in use in catheterisation laboratories is essential in order to optimise protection of patients and staff.

Body Constitution↗
PubMed2006

Forty years of 90Sr in situ migration: importance of soil characterization in modeling transport phenomena.

In 1960 experiments were carried out on the transfer of (90)Sr between soil, grapes and wine. The experiments were conducted in situ on a piece of land limited by two control strips. The (90)Sr migration over the last 40 years was studied by performing radiological and physico-chemical characterizations of the soil on eight 70 cm deep cores. The vertical migration modeling of (90)Sr required the definition of a triple layer conceptual model integrating the rainwater infiltration at constant flux as the only external factor of influence. Afterwards the importance of a detailed soil characterization for modeling was discussed and satisfactory simulation of the (90)Sr vertical transport was obtained and showed a calculated migration rate of about 1.0 cm year(-1) in full agreement with the in situ measured values. The discussion was regarding some of the key parameters such as granulometry, organic matter content (in the Van Genuchten parameter determination), Kd and the efficient rainwater infiltration. Besides the experimental data, simplifying assumptions in modeling such as water-soil redistribution calculation and factual discontinuities in conceptual model were examined.

Biological Transport↗
PubMed2006

Occupational radiation doses in interventional cardiology: a 15-year follow-up.

This report describes occupational radiation doses of interventional cardiologists over 15 years and assesses action undertaken to optimize radiation protection. Personal dosimetry records of nine staff cardiologists and eight interventional cardiology fellows were recorded using personal dosemeters worn over and under their lead aprons. The hospital in which this study was conducted currently performs 5000 cardiology procedures per year. The hospital has improved its facilities since 1989, when it had two old-fashioned theatres, to include four rooms with more advanced and safer equipment. Intensive radiation protection training was also implemented since 1989. Initially, some individual dose values in the range of 100-300 mSv month(-1), which risked exceeding some regulatory dose limits, were measured over the lead apron. Several doses in the range of 5-11 mSv month(-1) were recorded under the apron (mean = 10.2 mSv year(-1)). During the last 5 years of the study, after the implementation of the radiation protection actions and a programme of patient-dose optimization, the mean dose under the apron was reduced to 1.2 mSv year(-1). Current mean occupational doses recorded under the lead apron are 14% of those recorded during 1989-1992 and those recorded over the apron are 14-fold less than those recorded during 1989-1992. The regulatory dose limits and the threshold for lens injuries might have been exceeded if radiation protection facilities had not been used systematically. The most effective actions involved in reducing the radiation risk were training in radiation protection, a programme of patient-dose reduction and the systematic use of radiation protection facilities, specifically ceiling-suspended protective screens.

Body Burden↗
PubMed2005

Quality and freezing qualities of first and second ejaculates collected from endangered Gulf Coast Native rams.

The Gulf Coast Native sheep, or Louisiana Native sheep, is an endangered previously feral domestic sheep population of European origin that has been under natural selection pressure for reproductive survival in their transplanted range while roaming in the southern Gulf Coast Region of the United States. This sheep population has an increased natural resistance to internal parasites, breeds year-around and has a greater percentage of live lambs as compared with other breeds of sheep raised in similar environments. To preserve the genetic diversity of this important feral sheep population, semen was collected by electro-ejaculation and subjected to cryopreservation for subsequent storage in a genome resource bank. Unrelated rams (n=5) were collected 3 days-a-week, allowing at least 2 days of rest between collections. Two ejaculates were obtained from each ram per collection day, with the second collection conducted 10min after the first ejaculation. Semen was processed using the standard Salamon cryopreservation procedure in a Tris-yolk-glycerol extender, frozen in 0.5ml plastic straws using liquid nitrogen (LN(2)) vapor and stored in LN(2). Each ejaculate was evaluated for volume, sperm concentration/ml (x10(9)/ml), number of spermatozoa/ejaculate (x10(9)), sperm progressive motility (%) for pre-cooled semen, cooled semen and semen after thawing. For the five rams, each semen variable for the first ejaculate was compared with that of the second ejaculate collected 10min later. The mean semen volume, sperm concentration and number of spermatozoa per ejaculate obtained from the first ejaculate were significantly greater (P< or =0.01) than those of the second ejaculate (comparisons being 1.62 and 1.06; 3.2 and 1.5; 5.4 and 1.8, respectively). Overall, the mean motility of pre-cooled (22 degrees Celsius), cooled (5 degrees Celsius) and frozen (-196 degrees Celsius) post-thawed spermatozoa was less (P< or =0.01) in the first ejaculate (71.5, 64.8 and 34.1%, respectively) compared with that of the second ejaculate (75, 72.4 and 44.1%, respectively). Conversely, no differences were detected in loss in the percent progressive motility of sperm from cooled sperm to post-thaw sperm from the first and second ejaculates. In summary, our findings suggest sperm collected during the second ejaculate 10min after the first ejaculate of rams survives thawing with a greater rate of progressive motility than that of the first ejaculate. The ability to collect two consecutive ejaculates in a short period by electro-ejaculation could be valuable for gamete resource banking and preserving genetic diversity of the Gulf Coast Native sheep.

Animals↗
PubMed2005

L-carnitine supplementation does not promote weight loss in ovariectomized rats despite endurance exercise.

In this five-week study, we tested the hypotheses that free access to a maintenance diet supplemented with L-carnitine (L-C) would reduce body fat in adult, sedentary, ovariectomized (OVX) rats, and that there would be an additive effect of L-C on weight reduction in swim-trained animals. As expected, serum carnitine was higher in rats fed the L-C diet, and the OVX-induced weight gain and abdominal fat were counteracted by swimming. L-C supplementation did not reduce the weight gain or abdominal fat in these adult female rats, Moreover, though not reaching statistical significance, rats that were fed L-C demonstrated a tendency for greater weight gain than their basal-fed counterparts despite no difference in energy intake. If the results of this study on ovariectomized rats can be translated to postmenopausal women, moderate intensity exercise may be recommended, but L-C supplementation, with no energy restriction, may be contraindicated as a weight loss method in this cohort.

Abdomen↗
PubMed2005

Effects of dietary cation-anion difference on intake, milk yield, and blood components of the early lactation cow.

Early lactation Holsteins cows (15 primiparous and 18 multiparous) were offered rations with dietary cation-anion difference, calculated as mEq (Na + K - Cl - S)/100 g of feed dry matter (DCAD:S), of 20, 35, or 50 mEq from d 0 (calving) to 42 d postpartum (August 20, 2000 to January 9, 2001) to determine the effects of increasing DCAD:S on dry matter intake (DMI), milk yield, and blood metabolites. For DCAD:S of 20, 35, and 50, DMI was 3.30, 3.38, 2.96 kg/100 kg of body weight (BW); milk yield was 25.5, 24.2, and 22.4 kg/d, respectively. No differences were observed for concentration or yield of milk fat or milk protein. Serum Ca, P, Mg, Na, K, Cl, cation-anion difference, insulin, and glucose did not differ with DCAD. Serum HCO3- was 26.07, 25.88, and 27.64 mEq/L for 20, 35, and 50 DCAD:S. Serum Ca, Mg, Na, and K concentrations were greater for primiparous cows (9.52 mg/dL, 2.35 mg/dL, 140.03 mEq/L, 4.66 mEq/L, respectively) than for multiparous cows (9.27 mg/dL, 2.12 mg/dL, 137.63 mEq/L, 4.46 mEq/ L, respectively). A DCAD:S between 23 and 33 mEq/100 g of dry matter (DM) appears to be adequate during cool weather for the milk yield that occurred in the present study based on DMI (kg/100 kg of BW), whereas DCAD:S of 50 mEq/100 g of DM may be excessive and could be too alkaline or unpalatable, resulting in decreased DMI (kg/100 kg of BW).

Animals↗
PubMed2004

Flow paths of plant tissue residues and digesta through gastrointestinal segments in Spanish goats and methodological considerations.

A sequence of eight twice-daily meals, each marked with different rare earth elements, was fed to 24 Spanish goats (BW = 20.6 +/- 1.94 kg) to produce meal-based profiles of rare earth markers within segments of the gastrointestinal digesta on subsequent slaughter. Accumulative mean residence time and time delay of rare earths and segmental and accumulative mean residence times of indigestible NDF (IDF) were estimated for each sampled segment. Diets consisted of ad libitum access to bermudagrass hay with a limit feeding of one of four supplements: 1) minerals (basal, B); 2) B + energy (E); 3) B + CP (CP); or 4) B + E + CP for 84 d. Mean daily intake (g/kg of BW) during the 5 d before slaughter differed (P < 0.05) via diet for DM but not for IDF (8.0 +/- 0.35 g/kg of BW). Larger estimates of cumulative mean residence time for IDF vs. rare earths were suggested to be the consequence of a meal-induced bias in the single measurement of IDF pool size by anatomical site. The rare earth compartment method was considered more reliable than the IDF pool dilution method because it yielded flow estimates based on the flux of eight meal-dosed rare earth markers over 4 d and was independent of anatomical definitions of pool size. Statistically indistinguishable estimates for gastrointestinal mean residence times for IDF and rare earths conform to assumed indelibility for the specifically applied rare earths and indigestibility of IDF. The potentially digestible NDF (PDF):IDF ratio of dietary fragments (0.8) progressively decreased in the following order: caudodorsal reticulorumen (0.390) > crainodorsal reticulorumen (0.357) approximately reticulum (0.354) > mid-dorsal reticulorumen (0.291) approximately ventral reticulorumen (0.286), to that within the omasal folds and in the abomasum (0.259). Such a gradient of progressively aging mixture of plant tissue fragments is consistent with age-dependent flow paths established in the reticulorumen and flowing to the omasum and abomasum. Such heterogeneity of fragment ages within the reticulorumen is also indicated by the superior fit of marker dose site double dagger marker sampling site model assumptions. Additionally, cyclic meal- and rumination-induced variations in escape rate occur. Estimates of mean escape rates over days, needed for the practice of ruminant nutrition, must consider the complex interactions among plant tissues and the dynamics of their ruminal digestion of PDF.

Abomasum↗
PubMed2004

Effect of nonwaxy and waxy sorghum on growth, carcass traits, and glucose and insulin kinetics of growing-finishing barrows and gilts.

Two experiments were conducted to determine the effect of nonwaxy (amylose and amylopectin starch) or waxy (amylopectin starch) sorghum on growth, carcass traits, and glucose and insulin kinetics of pigs. In Exp. 1 (95-d), 60 crossbred barrows or gilts (initial and final BW of 24 and 104 kg) were allotted to three treatments with five replications of four pigs per replicate pen in a randomized complete block design. The dietary treatments for Exp. 1 were 1) corn-soybean meal (C-SBM) diet, 2) sorghum-SBM (red pericarp, non-waxy), and 3) sorghum-SBM (red pericarp, waxy). In Exp. 2, 28 crossbred barrows (initial and final BW of 24 and 64 kg) were allotted to two treatments with three replications of four or five pigs per replicate pen in a randomized complete block design. Growth data were collected for 49 d, and then 20 barrows were fitted with jugular catheters, and then a glucose tolerance test (500 mg glucose/kg BW), an insulin challenge test (0.1 IU of porcine insulin/kg BW), and a feeding challenge were conducted. The dietary treatments for Exp. 2 were 1) sorghum-SBM (white pericarp, nonwaxy) and 2) sorghum-SBM (white pericarp, waxy). In Exp. 1, ADG (P = 0.10) and ADFI (as-fed basis; P = 0.02) were increased (P = 0.10) and gain:feed was decreased (P = 0.04) in pigs fed the sorghum-SBM diets relative to those fed the C-SBM diet. These responses may have resulted from the lower energy content of sorghum relative to corn. Plasma NEFA concentration (collected after a 16-h fast on d 77) was decreased (P = 0.08) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. Kilograms of carcass fat was decreased (P = 0.07) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. In Exp. 2, there was no effect (P = 0.57 to 0.93) of sorghum starch type on growth performance by pigs. During the glucose tolerance and insulin challenge tests, there were no effects (P = 0.16 to 0.98) of diet on glucose or insulin kinetics. During the feeding challenge, glucose (P = 0.02) and plasma urea N (P = 0.06) area under the response curves from 0 to 90 min were decreased in pigs fed the waxy sorghum-SBM diet. Feeding waxy sorghum had minimal effects on growth and carcass traits relative to pigs fed corn or nonwaxy sorghum. Waxy sorghum vs. nonwaxy sorghum had no effect on glucose or insulin kinetics in pigs.

Amylopectin↗
PubMed2004

Beta-sarcoglycanopathy (LGMD 2E) in a Spanish family.

Out of 10 autosomal recessive limb-girdle muscular dystrophies reported, 4 are caused by mutations in the genes encoding for sarcoglycans (alpha-, beta-, gamma- and delta-SG). Beta-sarcoglycanopathy (limb-girdle muscular dystrophy 2E) is a genetically heterogeneous disorder which usually presents a severe progressive clinical course. A complete immunohistochemical evaluation of the sarcoglycan complex should be carried out to direct the mutation analysis approach. The present report concerns a Spanish family with a genetically confirmed beta-sarcoglycanopathy. The patient, a 16-year-old female, offspring of a consanguineous marriage, developed a severe limb-girdle muscular dystrophy with a Duchenne-like phenotype. Muscle biopsy showed dystrophic changes and complete absence of the four sarcoglycans. Genetic analysis demonstrated homozygosis for the M100K missense mutation in exon 3, encoding for the proximal extracellular domain. The parents and one sister were found to be carriers. Missense mutations affecting this domain result in the instability of the entire sarcoglycan complex and lead to severe phenotypes as seen in non-sense mutations.

Adolescent↗
PubMed2003

Skin dose and dose-area product values in patients undergoing intracoronary brachytherapy.

Entrance skin doses, dose-area product (DAP) values, fluoroscopy times and digital cine acquisition data were measured for 86 patients undergoing intracoronary brachytherapy procedures with beta sources, to estimate risk of skin injuries. Interventions were carried out in three dedicated X-ray interventional cardiology rooms equipped with X-ray systems operating in pulsed modes, with high filtration and edge filter options. Skin dose distribution was analysed in detail in 56 patients using slow films and thermoluminescent dosimetry. Digital recording of Digital Imaging and Communications in Medicine cine images also allowed analysis of the technical parameters used throughout the procedures. A protocol for clinical follow-up of these patients at the cardiology service is also presented, which prescribes special attention when a threshold dose is reached. Median values for DAP, fluoroscopy time and number of frames were 81.2 Gy cm(2), 17.5 min and 1569 frames, respectively, and maximum values were 323.3 Gy cm(2), 46.2 min and 3213 frames, respectively. In two cases, maximum skin doses in a procedure reached 3.5 Gy and 4.6 Gy. Comparing median values in this study, intracoronary brachytherapy involved approximately two-fold the DAP used in percutaneous transluminal coronary angioplasty procedures performed during the same period in the same catheterization laboratories, as a consequence of the need to monitor the radioactive source location used for the treatment of stenoses and the intravascular ultrasound. Special care must be paid in those cases of high dose in relation to potential patient skin injuries and late effects.

Brachytherapy↗
PubMed2003

Short communication: Practical aspects for the evaluation of skin doses in interventional cardiology using a new slow film.

Mapping skin doses in complex fluoroscopy interventions is useful to determine the probability of a possible injury, to detect areas of overlapping irradiation fields and to obtain a permanent register of the most exposed patient skin areas. To fulfil this task, large films with slow X-ray response can be used. Recently, Kodak has introduced a new radiotherapy verification film, named EDR2 (Extended Dose Range). The aim of this paper is to analyse the possibilities of using this new film for estimating skin dose distributions in interventions with potentially higher doses, such as complex percutaneous transluminal coronary angioplasty (PTCA), intravascular brachytherapy procedures (IVB) or cardiac ablations. The EDR2 film by Kodak is an improved option to be used in interventional cardiology to obtain maps of patient skin doses and to estimate maximum skin doses up to 1400 mGy. Film kVp dependence is negligible and the processor conditions can be standardized to obtain skin dose estimations. The linear range for accurate dose measurements is from 50 mGy to 500 mGy.

Angioplasty, Balloon, Coronary↗
PubMed2002

18F-fluoro-2-deoxyglucose-positron emission tomography in the evaluation of nonseminomatous germ cell tumours at relapse.

OBJECTIVES: To compare the performance of 18F-fluoro-2-deoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) in the follow-up of nonseminomatous germ cell tumours (NSGCT) in the retroperitoneum. PATIENTS AND METHODS: FDG-PET was used 25 times in 15 patients diagnosed with NSGCT. At the time of diagnosis five patients each were in stage I, II and III. Five patients had pure embryonal carcinoma, two had yolk sac tumours, one choriocarcinoma and seven had mixed tumours. RESULTS: Eleven patients either presented with retroperitoneal disease or this did not disappear after chemotherapy. The results of both examinations coincided in 18 cases and were contradictory in the other seven, the difference being statistically significant (P=0.042). CONCLUSION: In these patients FDG-PET detected the retroperitoneal relapse of NSGCT, in advanced stages treated with surgery plus chemotherapy, earlier than did CT; it also detected the presence of mature teratoma in residual retroperitoneal masses more accurately than CT. More extensive trials are needed before making conclusions about FDG-PET imaging as a routine method for NSGCT.

Adolescent↗
PubMed2002

Effects of feeding milk replacer once versus twice daily on glucose metabolism in Holstein and Jersey calves.

Eighteen Holstein (experiment 1) and 15 Jersey (experiment 2) heifer calves were fed milk replacer once or twice daily to determine effects of feeding frequency on weight gain, starter intake, and glucose metabolism. Body weights were measured weekly from birth to 8 wk. Blood samples were collected at wk 1 through 6 from all calves before and at 30, 60, 90, 120 and 180 min after the morning feeding. Plasma was analyzed for glucose, insulin, glucagon, and nonesterified fatty acids (NEFA). Urine was collected 90 min postfeeding to measure glucose concentration. Treatment did not affect mean starter intake or body weight. In experiments 1 and 2 mean plasma glucagon, glucose, NEFA, and insulin and urinary glucose concentrations were not affected by treatment. There was an interaction of sampling time and treatment for plasma insulin concentrations but not for glucose concentrations in both experiments. Following feeding, calves fed milk replacer once daily had higher insulin concentrations than those fed twice daily. There was an interaction of sampling time and treatment for plasma NEFA concentrations in Jersey calves only. Jersey calves fed milk replacer once daily had higher plasma NEFA concentrations before the morning milk replacer feeding. At wk 3 and 6, frequently sampled intravenous glucose tolerance tests were performed to assess glucose effectiveness, insulin sensitivity, and acute insulin response. In experiments 1 and 2 glucose effectiveness and insulin sensitivity were similar regardless of milk replacer feeding frequency. In Holstein and Jersey calves fed milk replacer twice daily, acute insulin response was greater than in calves fed once daily. However, insulin sensitivity decreased with age, while acute insulin response increased with age. These data suggest that feeding calves milk replacer once daily did not deleteriously affect performance or glucose metabolism regardless of breed.

Aging↗
PubMed2001

Detection of the 5'-cap structure of messenger RNAs with the use of the cap-jumping approach.

An effective procedure for specific determination of the cap structure at the 5'-terminus of mRNA and for isolation of the corresponding full-length cDNA has been developed. The procedure involves covalent attachment of an oligonucleotide template extender to the 5'-cap structure of mRNA followed by RT-PCR using M-MLV SuperScript II reverse transcriptase. In the course of reverse transcription, the enzyme 'jumps over' the cap structure and includes the sequence complementary to the oligonucleotide template extender into the 3'-end of the first cDNA strand. The cap-jumping method was successfully tested using some mammalian cellular mRNAs, genomic RNAs of tobacco mosaic virus (TMV) U1 and the recently isolated crucifer-infecting tobamovirus. Moreover, cDNA products corresponding to the genomic tobamovirus RNA were obtained from total RNA extracted from tobacco plants infected by crucifer-infecting tobamovirus or tobacco mosaic virus. Using the cap-jumping method, we have shown for the first time that genomic crucifer-infecting tobamovirus (crTMV) RNA contains a 5'-cap structure. This improved method can be recommended for the construction of full-length and 5'-end enriched cDNA libraries, identification of capped RNAs and determination of their 5'-terminal sequences.

5' Untranslated Regions↗