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J M Fernández

Publications and source records attributed to J M Fernández.

At least 19 recordsLinked to original sources
PubMed2006

Rotranslational state-to-state rates and spectral representation of inelastic collisions in low-temperature molecular hydrogen.

Inelastic collisions in natural H2 are studied from the experimental and theoretical points of view between 10 and 140 K. Rotational populations and number densities measured by Raman spectroscopy along supersonic expansions of H2 provide the link between experimental and theoretical rotranslational state-to-state rate coefficients of H2 in the vibrational ground state. These rates are calculated in the close-scattering approach with the MOLSCAT code employing a recent ab initio H2-H2 potential. The calculated rates are assessed by means of a master equation describing the time evolution of the experimental rotational populations. The feasibility for obtaining the rates on the sole basis of the experiment is discussed. The dominant processes j(1)j(2)-->j'(1)j'(2) in the investigated thermal range are found to be 21-->01 >30-->12 >31-->11, proving the importance of double processes such as 30-->12. Good agreement is found between theory and experiment, as well as with earlier ultrasonic measurements of relaxation times. A spectral representation is proposed in order to visualize quantitatively the collisional contributions in any nonequilibrium time evolving process.

Journal Article↗
PubMed2006

Six years experience in intracoronary brachytherapy procedures: patient doses from fluoroscopy.

Typical patient dose levels during intracoronary brachytherapy (ICB) procedures using beta sources were determined across a sample of 221 treatments. Dose-area product values, fluoroscopy time and number of frames per procedure, with median values of 62 Gy cm2, 17.0 min and 1493 images, respectively, resulted in a 20% to 50% increase in the values measured for percutaneous transluminal coronary angioplasty procedures in the same medical centre (median values 41 Gy cm2, 14.3 min and 1078 images). Likely reasons for this increase include the additional complexity of ICB, the need for recording and reporting every step of the treatment, getting the essential parameters for the volume determination of the lesion and therapeutic radiation dose calculation and, finally, the learning curve for this kind of procedure. A high concentration skin dose distribution during ICB procedures was measured and in 12% of the patients peak skin doses higher than 1.5 Gy were confirmed. 10 patients were submitted to clinical follow-up and skin injuries were not identified.

Angioplasty, Balloon, Coronary↗
PubMed2005

Autosomal dominant congenital fibre type disproportion: a clinicopathological and imaging study of a large family.

Congenital fibre type disproportion (CFTD) is considered a non-progressive or slowly progressive muscle disease with relative smallness of type 1 fibres on pathological examination. Although generally benign, CFTD has a variable natural course and severe progression has been observed in some patients. The pathogenesis of the disorder is unknown and many authors consider CFTD a syndrome with multiple aetiologies rather than a separate clinical entity. A positive family history has been reported in about 40% of cases, but the inheritance pattern is not clear. Both autosomal recessive and dominant modes of inheritance have been suggested. The present paper describes a large, multigenerational kindred that has an inherited myopathy fulfilling the histological criteria of CFTD, with autosomal dominant transmission and high penetrance. The clinical picture, remarkably similar in all affected family members, started in early infancy with mild limb muscle weakness. There was slow progression of symptoms into adulthood, with moderate to severe, mainly proximal, muscle weakness without loss of ambulation. Muscle biopsy from two affected individuals demonstrated predominance of small type 1 muscle fibres without other significant findings. Nerve conduction studies were normal and needle electromyography showed a myopathic pattern. MRI examination performed on three patients from successive generations showed involvement of proximal limb and paraspinal muscles. The clinical and pathological homogeneity in the present family, together with the lack of additional histological abnormalities after decades of disease progression in two affected individuals, supports this being a distinct myopathy with fibre type disproportion. Whether the disease in this family can be regarded as a form of the congenital myopathy known as CFTD or rather a unique condition sharing histological features with CFTD needs further investigation. This is, to our knowledge, the largest kindred with muscle fibre type disproportion reported to date. Our data confirm autosomal dominant inheritance, and this is the first MRI document of this disorder.

Adult↗
PubMed2005

Inelastic collisions in para-H2: translation-rotation state-to-state rate coefficients and cross sections at low temperature and energy.

We report an experimental determination of the k(00-->02) rate coefficient for inelastic H(2):H(2) collisions in the temperature range from 2 to 110 K based on Raman spectroscopy data in supersonic expansions of para-H(2). For this purpose a more accurate method for inverting the master equation of rotational populations is presented. The procedure permits us to reduce the measured k(00-->02) rate coefficient to the corresponding sigma(00-->02) cross section in the range of precollisional energy from 360 to 600 cm(-1). Numerical calculations of sigma(00-->02) carried out in the frame of the coupled channel method are also reported for different intermolecular potentials of H(2). A good agreement is found between the experimental cross section and the numerical one derived from Diep and Johnson's potential [J. Chem. Phys. 112, 4465 (2000)].

Journal Article↗
PubMed2005

[Bickerstaff's encephalitis].

INTRODUCTION: The clinical and radiological findings in a case of Bickerstaff encephalitis are described and the relationship with Miller Fisher and Guillain Barré syndromes are discussed. CLINICAL CASE: Subsequently to a respiratory infection,a 44-year-old male developed external ophthalmoplegia and cerebellar-like ataxia; his condition deteriorated and he suffered consciousness disturbances and absent tendon reflexes were noted. An MRI scan was performed showing a lesion affecting the brainstem. The cerebrospinal fluid (CSF) revealed albuminocytologic dissociation and the presence of oligoclonal bands. He received high doses of intravenous immunoglobulins and five months later, he had completely recovered. A follow up MRI scan demonstrated complete resolution of the lesion. CONCLUSIONS: The initial condition was diagnosed as Bickerstaff brainstem encephalitis (BBE) with overlapping peripheral nervous system semiology. The presence during the acute phase of oligoclonal bands in CSF, which decreased with the clinical improvement, supports the hypothesis than an autoimmune mechanism may function in its pathogenesis. Our case suggests that intravenous immunoglobulins therapy should be considered in patients with BBE.

Adult↗
PubMed2004

Comparison between experimental and calculated vehicle idle emission factors for Madrid fleet.

Experimental vehicle idle emission factors have been compared with calculated factors for 100 vehicles in Madrid. The vehicles were selected according to the distribution (by age and fuel type) of the official, national car fleet (up to 31 December 1997). They were then clustered following the criteria of the Computer Programme to Calculate Emissions from Road Transport (COPERT III) category classification. NO(x) and CO idle emission factors show a wide range of values in each category and an important deviation between the experimental values and the corresponding parameterised ones. Fifteen percent of tested vehicles in this study have been identified as gross emitters generating approximately 50% of the total CO emission volume.

Journal Article↗
PubMed2004

Raman spectroscopy of small para-H2 clusters formed in cryogenic free jets.

Small para-H2 clusters (pH2)N with N=2,...,8 have been identified by Raman spectroscopy in cryogenic free jets of the pure gas, near the Q(0) Raman line of the H2 monomer. The high resolution in space, time, and number size makes it possible to follow their growth kinetics with distance from the orifice. At lower source temperatures liquid clusters appear early in the expansion and then undergo a gradual phase transition to the solid state. The technique is very promising for exploring superfluidity in pure (pH2)N clusters.

Journal Article↗
PubMed2004

Long-term results of high-dose chemotherapy and autologous stem cell rescue for high-risk neuroblastoma patients: a report of the Spanish working party for BMT in children (Getmon).

The authors retrospectively analyzed the long-term outcome of 67 patients over 1 year of age at diagnosis with high-risk neuroblastoma (stage 4 or stage 3 with N-myc amplification) who were treated with megatherapy and stem cell rescue from 1984 to 1998. Median age at transplant was 4 years (range 1.6-15 years). The source of cells was peripheral stem cells in 29 and bone marrow in 38 patients. In 12 patients, an in vitro purging of bone marrow harvest was performed. Most patients were conditioned with melphalan, BCNU, and VM-26. After transplant 19 patients received complementary treatment with IL-2 (16) or 13-cis-retinoic acid (3). Six patients (8%) died from transplant-related toxicity and 39 from disease progression. Three patients were alive with active disease at the time of analysis. Nineteen patients are alive and disease-free at a median follow-up of 104 months. Five-year event-free survival is 0.30. Survival of patients who received a purged graft was not significantly better than the rest. Post-transplant complementary treatment significantly improved overall and event-free survival (p = .01 and p = .04, respectively).

Adolescent↗
PubMed2004

Minimal residual disease in neuroblastoma: to GAGE or not to GAGE.

We assessed the utility of GAGE gene expression as a marker of minimal residual disease (MRD) in neuroblastoma. The GAGE gene family shows a high degree of homology (>90%), clustering into two subgroups. GAGE-1, -2, and -8 form one subset, almost identical among themselves, while GAGE-3 to -7 constitute the other subset. The entire GAGE family (GAGE-1-8) was studied by RT-PCR followed by Southern blotting to increase both the sensitivity and specificity of the technique. Surprisingly, expression of GAGE was detected in 59% of peripheral blood samples from normal controls (20/35) as well as in a similar proportion from neuroblastoma patients with localized disease (stages 1 and 2). The study of GAGE-1, -2, and -8 with specific primers lowered this percentage to 28% (10/35), of which only two (6%) showed a high level of expression (directly visualized after RT-PCR). We conclude that GAGE genes can show a variable, usually low level of illegitimate expression in normal blood cells, and therefore their use as MRD markers should be taken with caution.

Antigens, Neoplasm↗
PubMed2004

[First non-autologous vascular access for hemodialysis: PTFE fistula].

INTRODUCTION: Since 1999 to 2003 we have tried to perform an antebraquial "loop" PTFE fistula (PTFEa) as first vascular access for hemodialysis in patients without suitable superficial venous system. MATERIAL AND METHODS: We have performed a prospective study to analyze the results (permeability and complications) with this approach. RESULTS: We could perform 44 PTFEa in 46 consecutive patients (in two cases we used the axillary vein as return vessel). Early failure was 0%. One year primary and secondary permeability were 66% and 90% respectively. CONCLUSIONS: PTFEa is a good solution as first vascular access in patients without a suitable superficil venous system.

Aged↗
PubMed2003

[Bone scintigraphy and somatostatin receptor scintigraphy in pediatric patients with bone involvement in Langerhans cell histiocytosis].

Langerhans cell histiocytosis (LCH) is a granulomatous disease which can involve multiples sites of the body. Diagnostic imaging is of utmost importance in the management of these patients. Up to now radiographic skeletal survey and bone scintigraphy (BS) have been used to assess bone involvement (both with low specificity). Magnetic resonance imaging (MRI) and CT have been used to assess visceral involvement but with the limitation that they cannot give information about the functional status. Recently somatostatin receptor scintigraphy (SSRS) has been proposed to detect active lesions and to monitor response to treatment. The aim of this study is to assess bone and somatostatin receptor scintigraphy in the detection of bone involvement in LCH in children. Twenty scintigraphies (12 SSRS and 8 BS) were performed in seven patients (3 girls and 4 boys) aged at diagnosis: 18 month-12 years (mean age 6 years). The findings obtained in the scintigraphies were compared with clinical evolution and other imaging techniques. Bone scintigraphy detected all the LCH bone lesions, and discovered one unknown lesion. SSRS scintigraphy visualised the active lesions in 3 patients (clinical and other imaging techniques were also positive). SSRS was negative in one patient classified as disease free and another in clinical remission. SSRS detected 2 new unknown bone lesions, but could not detect LCH bone lesions confirmed in other imaging techniques in 2 patients. Somatostatin receptor and Bone scintigraphy can be used to detect active LCH bone lesions in children and can help to monitor response to treatment. Further studies with more patients are needed to confirm the diagnostic usefulness of these techniques.

Biomarkers↗
PubMed2003

Pre-test prediction models of BRCA1 or BRCA2 mutation in breast/ovarian families attending familial cancer clinics.

OBJECTIVE: To test whether statistical models developed to calculate pre-test probability of being a BRCA1/2 carrier can differentiate better between the breast/ovarian families to be referred to the DNA test laboratory. STUDY DESIGN: A retrospective analysis was performed in 109 Spanish breast/ovarian families previously screened for germline mutations in both the BRCA1 and BRCA2 genes. Four easy to use logistic regression models originally developed in Spanish (HCSC model), Dutch (LUMC model), Finnish (HUCH model), and North American (U Penn model) families and one model based on empirical data of Frank 2002 were tested. A risk counsellor was asked to assign a subjective pre-test probability for each family. Sensitivity, specificity, negative and positive predictive values, and areas under receiver operator characteristics (ROC) curves were calculated in each case. Correlation between predicted probability and mutation prevalence was tested. All statistical tests were two sided. RESULTS: Overall, the models performed well, improving the performances of a genetic counsellor. The median ROC curve area was 0.80 (range 0.77-0.82). At 100% sensitivity, the median specificity was 30% (range 25-33%). At 92% sensitivity, the median specificity was 42% (range 33.3-54.2%) and the median negative predictive value was 93% (range 89.7-98%). BRCA1 families tended to score higher risk than BRCA2 families in all models tested. CONCLUSIONS: All models increased the discrimination power of an experienced risk counsellor, suggesting that their use is valuable in the context of clinical counselling and genetic testing to optimise selection of patients for screening and allowing for more focused management. Models developed in different ethnic populations performed similarly well in a Spanish series of families, suggesting that models targeted to specific populations may not be necessary in all cases. Carrier probability as predicted by the models is consistent with actual prevalence, although in general models tend to underestimate it. Our study suggests that these models may perform differently in populations with a high prevalence of BRCA2 mutations.

BRCA1 Protein↗
PubMed2002

Apolipoprotein E genotype and schizophrenia: further negative evidence.

OBJECTIVE: To investigate the association between apolipoprotein E (ApoE) genotype and schizophrenia. METHOD: We genotyped 106 schizophrenic out-patients [Diagnostic Statistic Manual IV (DSM-IV) criteria] and 250 healthy volunteers (hospital staff and blood donors) from Asturias (Northern Spain). The ApoE genotypes (epsilon2, epsilon3, epsilon4-alleles) were determined after polymerase chain reaction (PCR) amplification, followed by digestion with the restriction enzyme Cfol and electrophoresis on a 4% agarose gel. RESULTS: No significant differences in ApoE-allele frequencies between patients and controls was found, although an increased 64-frequency was recorded in patients compared with controls [9.0% vs. 6.2%, P = 0.124; odds ratio (OR) = 1.49; 95% confidence interval (CI) = 0.82-2.70]. ApoE-genotype frequencies did not differ between both groups. The mean age of onset for schizophrenic patients that carried the epsilon4-allele was not significantly different from that of patients without this allele. CONCLUSION: Variation in the ApoE gene was not associated with the development of schizophrenia in our population. ApoE-genotypes did not modify the age of onset of the disease.

Adult↗
PubMed2002

Vitamin A, retinol binding protein and lipids in type 1 diabetes mellitus.

OBJECTIVE: A case-control study was conducted to evaluate the effects of type 1 diabetes mellitus (IDDM) on plasma levels of vitamin A (retinol) and serum levels of retinol-binding protein (RBP) and their relationship with the atherogenic indicators. SUBJECTS: A total of 47 randomised IDDM children were recruited from those treated at the Endocrinology Unit of the University Hospital of Granada (Spain). They were matched for age and sex with 16 healthy children. METHODS: The following parameters were measured in all patients: serum concentrations of total cholesterol, triglycerides, high (HDL, spectrophotometry), very low (VLDL) and low (LDL) density lipoprotein cholesterol (Friedewald's formula); serum levels of RBP (kinetic nephelometry); plasma vitamin A and glycosilated haemoglobin (HbA1c; high performance chromatography). RESULTS: Higher RBP concentrations in IDDM children (P=0.05), lower retinol levels (P=0.05) and lower vitamin A/cholesterol ratio (P=0.02) than in the control group were found; no differences in the atherogenic indicators were observed. There was a correlation between RBP and vitamin A (P=0.0001). Relationships between retinol, RBP and atherogenic indicators were demonstrated in the IDDM group (A-LDLc/HDLc (P=0.01); A-(VLDL+LDL)c/HDLc (P=0.007); RBP-LDLc/HDLc (P=0.05); RBP-(VLDL+LDL)c/HDLc (P=0.02)), and an inverse relationship was found between the vitamin A/TG ratio and HbA1c (P=0.004). The children with HbA1c>8% showed increased atherogenic indicators and lower vitamin A/CHOL and vitamin A/TG ratios than those with good control of the illness. CONCLUSIONS: The IDDM children with poor metabolic control face a higher atherogenic risk and vitamin A 'relative deficiency' risk than those with good metabolic control of their illness. Relationships between retinol and RBP with atherogenic indicators were found. The results suggest that vitamin A therapeutic supplements in IDDM children may reduce or prevent atherogenic risk.

Adolescent↗
PubMed2002

Long-term outcome of patients with asystole induced by head-up tilt test.

AIMS: To analyse the long-term outcome of the largest reported cohort of patients presenting asystole during head-up tilt test. METHODS AND RESULTS: Since 1990, 1322 patients with syncope of unknown origin have undergone tilt-table testing. Of those, 330 patients (24 X 9%) presented an abnormal response (syncope or pre-syncope). Furthermore, 58 of those patients (17 X 5%) suffered a period of asystole (> or = 3000 ms) during the test. Asystole (median (interquartile range)) lasted 10 (4, 19 X 2) s (range 3-90). Two different protocols (angles) of tilting (Westminster (60 degrees) n=1124; isoproterenol (80 degrees) n=198)) influenced the time to the syncopal episode (13 (6 X 5, 20 X 5) vs 2 (1, 6 X 5) min, P=0,0005) but not the duration of the asystole. During this period, therapy for asystole featured three different stages: first patients were treated with pacemakers; later drug therapy (metoprolol and/or etilefrine) was recommended; lastly (from 1995), no specific treatment was given. In a cohort age- and gender-matched study, those patients without were compared to those with asystole in a 2:1 basis. During 40 X 7 months of follow-up (17 X 7, 66 X 8), 12 patients (20 X 6%) with asystole had syncopal recurrences. Furthermore, 34 patients (28 X 8%) without asystole presented syncopal episodes during a follow-up of 51 X 6 months (29 X 3, 73 X 1) (P=ns). The Kaplan-Meier analysis in patients with and without asystole showed a mean time free of recurrence of 92 X 6 +/- 6 months vs 82 X 6 +/- 4 X 7 months (P=ns). The previous number of syncopes had a significant relationship with recurrences (P=0 X 002), but not therapy. There were no cardiac related deaths. CONCLUSIONS: (1) Asystole during head-up tilt test does not imply a malignant outcome and syncope recurrence is low; (2) pacemaker or drug therapy do not significantly influence outcome which correlates to the previous number of syncopal episodes but not to gender, age, asystole occurrence, asystole duration and timing to asystole during head-up tilt test; (3) tilting protocol (angle) might influence time to and incidence of asystole during head-up tilt test.

Adult↗
PubMed2001

Anaerobic treatment of fibreboard manufacturing wastewaters in a pilot scale hybrid usbf reactor.

The treatment of fibreboard manufacturing (FBM) wastewaters was carried out in an industrial pilot plant, which consisted of a hybrid upflow sludge bed filter (USBF) anaerobic reactor and a coagulation-flocculation unit as a pre-treatment. COD removal efficiencies of 90-93% were attained in the anaerobic reactor operating at 37degrees C at organic loading rates (OLR) of 6.5-8.5 kg COD/m3 d. Flocculant sludges were used as inoculum, and granulation was observed in the USBF reactor after 120 days of operation. The overall linear upward velocity (result of liquid and gas flow) was the key factor controlling biomass retention and, therefore, a stable operation at high OLR. According to ecotoxicity values (measured by means of bioluminescence assays), the wastewaters were partially detoxified, being EC50 values for the liquid effluent 25 times lower than those corresponding to the influent. Besides, phenolic compounds removal efficiencies of 90% were attained. The hybrid reactor configuration is an interesting alternative to treat these wastewaters since it is less sensitive to biomass clogging or floatation.

Bacteria, Anaerobic↗