Biomedical subjects

A Fernandez

Publications and source records attributed to A Fernandez.

At least 19 recordsLinked to original sources

PubMed2006

Induction of heavy-metal-transporting CPX-type ATPases during acid adaptation in Lactobacillus bulgaricus.

Lactobacillus bulgaricus is a lactic acid bacteria (LAB) that, through the production of lactic acid, gradually acidifies its environment during growth. In the course of this process, L. bulgaricus acquires an improved tolerance to acidity. A survey of the recently established genome sequence shows that this bacterium possesses few of the pH control functions that have been described in other LAB and raises the question of what other mechanisms could be involved in its adaptation to the decreasing environmental pH. In some bacteria other than LAB, ion transport systems have been implicated in acid adaptation. We therefore studied the expression of this type of transport system during acid adaptation in L. bulgaricus by reverse transcription and real-time quantitative PCR and mapped transcription start sites. Intriguingly, the most significantly induced were three ATPases carrying the CPX signature of heavy-metal transporters. Protein homology and the presence of a conserved sequence motif in the promoter regions of the genes encoding these proteins strongly suggest that they are involved in copper homeostasis. Induction of this system is thought to assist in avoiding indirect damage that could result from medium acidification.

Adaptation, Physiological↗

PubMed2006

Tolerance, safety and efficacy of Hedera helix extract in inflammatory bronchial diseases under clinical practice conditions: a prospective, open, multicentre postmarketing study in 9657 patients.

In this postmarketing study 9657 patients (5181 children) with bronchitis (acute or chronic bronchial inflammatory disease) were treated with a syrup containing dried ivy leaf extract. After 7 days of therapy, 95% of the patients showed improvement or healing of their symptoms. The safety of the therapy was very good with an overall incidence of adverse events of 2.1% (mainly gastrointestinal disorders with 1.5%). In those patients who got concomitant medication as well, it could be shown that the additional application of antibiotics had no benefit respective to efficacy but did increase the relative risk for the occurrence of side effects by 26%. In conclusion, it is to say that the dried ivy leaf extract is effective and well tolerated in patients with bronchitis. In view of the large population considered, future analyses should approach specific issues concerning therapy by age group, concomitant therapy and baseline conditions.

Adolescent↗

PubMed2005

Pulmonary amoebiasis presenting as superior vena cava syndrome.

Pulmonary amoebiasis without liver involvement occurs sporadically as a result of haematogenous spread from a primary site, the colon. The case history is presented of a patient who developed superior vena cava syndrome due to a pulmonary amoebic abscess without liver involvement. He was initially suspected of having a neoplasm but a combination of tests including histological examination of the H&E stained excised tissue, immunofluorescence using anti-Entamoeba histolytica antibodies, and serology confirmed the diagnosis of amoebiasis. To our knowledge this is the first description of pulmonary amoebiasis presenting as superior vena cava syndrome.

Adult↗

PubMed2004

Chirped-pulse oscillators: a route to high-power femtosecond pulses without external amplification.

We demonstrate a Kerr-lens mode-locked Ti:sapphire oscillator that generates 130-nJ, 26-fs and 220-nJ, 30-fs pulses at a repetition rate of 11 MHz. The generation of stable broadband, high-energy pulses from an extended-cavity oscillator is achieved by the use of chirped multilayer mirrors to produce a small net positive dispersion over a broad spectral range. The resultant chirped picosecond pulses are compressed by a dispersive delay line that is external to the laser cavity. The demonstrated peak powers, in excess of 5 MW, are to our knowledge the highest ever achieved from a cw-pumped laser and are expected to be scalable to tens of megawatts by an increase in the pump power and (or) a decrease in the repetition rate. The demonstrated source permits micromachining of any materials under relaxed focusing conditions.

Journal Article↗

PubMed2004

Cortical organization for receptive language functions in Chinese, English, and Spanish: a cross-linguistic MEG study.

Chinese differs from Indo-European languages in both its written and spoken forms. Being a tonal language, tones convey lexically meaningful information. The current study examines patterns of neurophysiological activity in temporal and temporoparietal brain areas as speakers of two Indo-European languages (Spanish and English) and speakers of Mandarin-Chinese were engaged in a spoken-word recognition task that is used clinically for the presurgical determination of hemispheric dominace for receptive language functions. Brain magnetic activation profiles were obtained from 92 healthy adult volunteers: 30 monolingual native speakers of Mandarin-Chinese, 20 Spanish-speaking, and 42 native speakers of American English. Activation scans were acquired in two different whole-head MEG systems using identical testing methods. Results indicate that (a) the degree of hemispheric asymmetry in the duration of neurophysiological activity in temporal and temporoparietal regions was reduced in the Chinese group, (b) the proportion of individuals who showed bilaterally symmetric activation was significantly higher in this group, and (c) group differences in functional hemispheric asymmetry were first noted after the initial sensory processing of the word stimuli. Furthermore, group differences in the degree of hemispheric asymmetry were primarily due to greater degree of activation in the right temporoparietal region in the Chinese group, suggesting increased participation of this region in the spoken word recognition in Mandarin-Chinese.

Adolescent↗

PubMed2004

Patient and direct-care staff body mass index in a state mental hospital: implications for management.

OBJECTIVE: Obesity is a major problem among chronically psychotic patients. METHOD: We assessed body mass index (BMI) of chronically psychotic patients on admission to a state mental hospital and in follow-up. We also compared patient BMI to staff BMI. RESULTS: The initial patient BMI (26.4 +/- 5.8 kg/m2) was in the overweight range. The patient BMI (29.1 +/- 5.8 kg/m2) increased (P < 0.0001) on follow-up and almost reached the level of obesity. Staff BMI (35.1 +/- 8.6 kg/m2) was in the obese range with 64.9% meeting criteria of obesity and 29.9% meeting criteria of morbid obesity. African-American women made up 84.5% of clinical-care staff and constitute the race-sex mix most vulnerable to obesity in the US. Morbid obesity (BMI > or = 40 kg/m2) was five times more common among these African-American female clinical-care staff than among African-American women in the general US population. CONCLUSION: Our findings may have treatment implications for chronically psychotic patients at risk for obesity.

Adult↗

PubMed2004

Profiles of brain magnetic activity during a memory task in patients with Alzheimer's disease and in non-demented elderly subjects, with or without depression.

The presence of depression is common among the elderly and it often complicates the early diagnosis of Alzheimer's disease (AD). In this study, we searched for brain activity measures that characterise AD. We compared brain magnetic activity profiles during a memory task, obtained from patients with AD, elderly patients with late onset depression, and age matched volunteers without history of neurological or psychiatric disease. AD patients showed significantly reduced activity in left temporal lobe regions during late portions of the event related magnetic response (400 ms or later after stimulus onset), compared with both groups of patients who did not present with serious cognitive decline. This finding highlights the potential usefulness of MEG protocols supporting the differential diagnosis of AD and major depression related cognitive decline in the elderly.

Age of Onset↗

PubMed2003

Ferromagnetism in fcc twinned 2.4 nm size Pd nanoparticles.

The onset of ferromagnetism has been experimentally observed in small Pd particles of average diameter 2.4 nm. High-resolution studies reveal that a high percentage of the fcc particle exhibits single and multiple twinning boundaries. The spontaneous magnetization close to 0.02 emu/g seems to indicate that only a small fraction of atoms holds a permanent magnetic moment and contributes to ferromagnetism. The possible origin of ferromagnetism is briefly discussed according to different models recently reported.

Journal Article↗

PubMed2003

Aggressive conservative treatment of esophageal perforations in children.

BACKGROUND/PURPOSE: In contrast with adult patients in whom surgical closure of the defect is preferred, nonoperative treatment has been the usual approach for esophageal perforation (EP) in children. This report aims to assess whether this strategy stands the passage of time. METHODS: We reviewed retrospectively the charts of 17 patients aged 5.3 +/- 0.9 years (mean +/- SD) treated at our institution for EP between 1991 and 2001. RESULTS: Nineteen episodes of EP were caused by stricture dilation in 9 cases, foreign body extraction in 3, and blunt trauma and sclerosis of varices in 2 cases each. The remaining child had multiple gastrointestinal perforations in the course of chemotherapy for leukemia. Vigorous treatment, consisting of nasopharyngeal aspiration, wide spectrum antibiotics, prompt drainage of effusions and either parenteral or infraesophageal nutritition, was implemented immediately after diagnosis. Perforations were closed without direct surgery in 18 of 19 episodes (16 of 17 children). One or more pleural drains were inserted in 12 cases, and pericardial drainage was required once. Seven gastrostomies, 2 jejunostomies, and one esophagostomy were performed. Several major abdominal operations were necessary to repair concomitant lesions in a child who sustained severe blunt abdominal trauma and in the patient with leukemic perforations. All patients survived, and all recovered esophageal function. However, 2 with intractable lye strictures ultimately required esophageal replacement. The only patient in whom a direct approach for esophageal necrosis due to variceal endosclerosis was unavoidable, lost her organ and had a retrosternal colonic interposition after a successful portosystemic shunt. Excluding patients with other concomitant lesions and the patient who underwent surgery, median length of stay was 11 days (range, 6 to 47). CONCLUSIONS: Prompt and aggressive nonoperative treatment of esophageal perforations in children allows survival with conservation of the organ in most cases and remains, in the authors' hands, the first therapeutic choice at this age.

Abdominal Injuries↗

PubMed2002

Dalitz plot analysis of the decay D(+)-->K(-)pi(+)pi(+) and indication of a low-mass scalar Kpi resonance.

We study the Dalitz plot of the decay D(+)-->K(-)pi(+)pi(+) with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known Kpi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K(*)(0)(1430) to float, we obtain values consistent with those from PDG but the chi(2) per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797+/-19+/-43 MeV/c(2) and width 410+/-43+/-87 MeV/c(2). The mass and width of the K(*)(0)(1430) become 1459+/-7+/-5 MeV/c(2) and 175+/-12+/-12 MeV/c(2), respectively. Our results provide new information on the scalar sector in hadron spectroscopy.

Journal Article↗

PubMed2002

D-2-Hydroxyglutaric aciduria in a patient with a severe clinical phenotype and unusual MRI findings.

We report an infant with intermittent urinary excretion of D-2-hydroxyglutaric (D-2-OHG) acid who died at the age of 10 months from cardiogenic shock due to cardiomyopathy. High urinary concentrations of D-2-OHG and succinic acid, as well as increased levels of lactic acid were detected on three different occasions, whereas a normal urinary profile of organic acids was found on one occasion. The clinical findings of our patient consisted of generalized hypotonia, irritability, developmental delay, generalized tonic seizures, lethargy, cardiomyopathy, and respiratory distress. Cerebral MRI revealed bilateral lesions in the substantia nigra, the periaqueductal area, the medial part of the thalamus, the hypothalamus, the caudate nucleus, putamen and globus pallidus. This pattern is suggestive of a mitochondriopathy. However, respiratory chain enzyme activities were normal in fibroblasts. Exogenous supplementation of D-2-OHG acid strongly inhibited cytochrome-c oxidase activity in fibroblasts from the patient and from normal controls in vitro. The results suggest that our patient has an unusual form of D-2-hydroxyglutaric aciduria (D-2-OHGA), different from the patients published so far, and that the increase of lactic acid and some citric acid cycle intermediates encountered in some patients with D-2-OHGA may be due to a functional defect of the respiratory chain caused by D-2-OHG acid.

Brain↗

PubMed2002

Immunohistochemical detection of Mycoplasma agalactiae in formalin-fixed, paraffin-embedded tissues from naturally and experimentally infected goats.

Samples from the mammary tissue of 14 lactating goats (12 naturally infected and two experimentally infected) were examined for the presence of Mycoplasma agalactiae. A monoclonal antibody (5G12) was applied to formalin-fixed, paraffin-wax-embedded sections and labelled by the avidin-biotin peroxidase complex (ABC) method. Histological examination of tissue sections revealed strong immunoreactivity in all animals included in the study. Mycoplasma agalactiae antigen was mainly detected in the cellular debris at the periphery of purulent exudates present within lactiferous sinuses, and lactiferous and interlobular ducts. In addition, M. agalactiae organisms appeared in the cytoplasm of the epithelium of ducts, and in infiltrating macrophages and neutrophils within the ducts, alveoli, interstitial tissue and regional lymph node sinuses. It is concluded that this monoclonal antibody-based immunohistochemical technique is an efficient and specific method for the post-mortem detection of M. agalactiae in cases of clinical mastitis as well as being a useful tool for the study of the route of infection and cellular types involved during mastitis caused by this organism.

Animals↗

PubMed2002

Sentinel node localization in patients with non-palpable breast cancer.

The aim of this study was to demonstrate that radionuclide sentinel node detection can be applied to patients with non-palpable breast cancer. One hundred and ten consecutive women with unilateral breast cancer were studied. Group 1 was made up of 80 patients with palpable breast cancer (mean age, 58 years) and group 2 of 30 patients with non-palpable breast cancer detected mammographically (mean age, 55 years). Tc-nanocolloid (111 MBq) was injected peritumorally in palpable tumours, and in the tumour area (ultrasound guided) in non-palpable tumours. At 2 h post-injection, anterior and lateral scintigrams were obtained from patients in the supine position. The location of the sentinel node was marked on the patient's skin. Patients with non-palpable tumours were moved to the surgery room 3 h later, and those with palpable tumours 24 h later. The histopathological study included three haematoxylineosin sections and immunochemistry. All patients underwent axillary lymphadenectomy. The sentinel node was detected in 67 cases (84%) in group 1 and in 28 cases (93%) in group 2. In four patients (5%) in group 1 and two patients (7%) in group 2, no axillary sentinel node was detected in the surgical bed, although it had been seen in scintigraphy. In nine patients (11%) in group 1, neither scintigraphic nor surgical detection was successful. Skip metastasis was seen in six cases (10%) of palpable tumours and in one case (4%) of non-palpable tumours. It can be concluded that non-palpable breast tumours cannot be considered an exclusion criterion for sentinel node localization and biopsy. Ultrasonography-guided injection, followed by scintigraphic and surgical detection of the sentinel node, may help in the management of patients with non-palpable breast tumours.

Adult↗

PubMed2002

Multicenter study on spreading of the tet(M) gene in tetracycline-resistant Streptococcus group G and C isolates in Argentina.

A prospective multicenter study on invasive infections caused by beta-hemolytic streptococci was performed over 6 months and involved 42 centers from 16 cities in Argentina. Among 33 isolates recovered, 9 group G Streptococcus isolates (39.1%) and 2 group C Streptococcus isolates (20%) exhibited resistance to tetracycline and harbored the tet(M) gene. Genealogical analysis revealed that tetracycline resistance has a polyclonal origin in Argentina.

Argentina↗

PubMed2001

A protein G fragment from the salmonid viral hemorrhagic septicemia rhabdovirus induces cell-to-cell fusion and membrane phosphatidylserine translocation at low pH.

The fusion-related properties of segments p9, p3, p4, and p9 + p2 surrounding the p2 phospholipid-binding domain of the protein G (pG) of the salmonid rhabdovirus of viral hemorrhagic septicemia (VHS) (Nuñez, E., Fernandez, A. M., Estepa, A., Gonzalez-Ros, J. M., Gavilanes, F., and Coll, J. M. (1998) Virology 243, 322-330; Estepa, A., and Coll, J. M. (1996) Virology 216, 60-70), have been studied at neutral and fusion (low) pH values by using its derived peptides. Cell-to-cell fusion, translocation of phosphatidylserine, and inhibition of fusion of pG-transfected cells defined the p9 + p2 (fragment 11, sequence 56-110) as a fragment with higher specific activity for anionic phospholipid aggregation than the previously reported p2. While fragment 11, p2, and p3 showed interactions with anionic phospholipids, p9 and p4 showed no interactions with any phospholipids. When added to a cell monolayer model at low pH, fragment 11 induced pH-dependent cell-to-cell fusion and translocated phosphatidylserine from the inner to the outer leaflet of the membrane. At low pH and in the presence of anionic phospholipids, fragment 11 showed more than 80% beta-sheet conformation (IR and CD spectroscopies). Finally, anti-fragment 11 antibodies inhibited low pH-dependent pG-transfected cell-to-cell fusion. All of the data support the conclusion that fragment 11 is a primary determinant of some of the viral cell fusion events in VHSV.

Amino Acid Sequence↗

PubMed2001

Heterogeneity of angiogenic activity in a human liposarcoma: a proposed mechanism for "no take" of human tumors in mice.

BACKGROUND: Tumor cells are known to be heterogeneous with respect to their metastatic activity, proliferation rate, and activity of several enzymes. However, little is known about the heterogeneity of tumor angiogenic activity. We investigated whether heterogeneity of angiogenic activity could be responsible for the well-known observation of "no take" of human tumors transplanted into immunodeficient mice. METHODS: Severe combined immunodeficient (SCID) mice were xenotransplanted subcutaneously with tumor tissue (n = 55) or cell suspension of a human liposarcoma cell line (SW-872) or subclones (n = 28), with varying cell proliferation rates. Xenograft tumor growth was recorded for up to 6 months. Tumor tissues were then removed and analyzed for tumor cell apoptosis, microvessel density, and cell proliferation. All statistical tests were two-sided. RESULTS: Pieces of tumor derived from the parental cell line or its clones gave rise to three kinds of tumors: 1) highly angiogenic and fast-growing (aggressive) tumors, 2) weakly angiogenic and slow-growing tumors, and 3) nonangiogenic and stable tumors. Most tumors retained the original phenotype of their parental tumor. Tumor volume correlated positively with microvessel density (Spearman correlation coefficient [r] =.89; P< or =.0001) and inversely with tumor cell apoptosis (Spearman r = -.68; P =.002). Tumor volume was less strongly but still positively correlated with tumor cell proliferation in vivo (Spearman r =.55; P =.02). CONCLUSIONS: Human liposarcoma cells appear to be heterogeneous in their angiogenic activity. When tumor cells with little or no angiogenic activity are transplanted into SCID mice, a microscopic, dormant tumor results that may not grow further. Because such tiny tumors are neither grossly visible nor palpable, they have previously been called "no take." The finding that an angiogenic tumor can contain subpopulations of tumor cells with little or no angiogenic activity may provide a novel mechanism for dormant micrometastases, late recurrence, and changes in rate of tumor progression.

Animals↗

PubMed2001

Direct measurement of the pion valence-quark momentum distribution, the pion light-cone wave function squared.

We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c pi(-) into dijets from a platinum target at Fermilab experiment E791. The results show that the /q&q> light-cone asymptotic wave function describes the data well for Q2 approximately 10 (GeV/c)(2) or more. We also measured the transverse momentum distribution of the diffractive dijets.

Journal Article↗

PubMed2001

Observation of color-transparency in diffractive dissociation of pions.

We have studied the diffractive dissociation into dijets of 500 GeV/c pions scattering coherently from carbon and platinum targets. Extrapolating to asymptotically high energies (where t(min)-->0), we find that when the per-nucleus cross section for this process is parametrized as sigma = sigma0Aalpha, alpha has values near 1.6, the exact result depending on jet transverse momentum. These values are in agreement with those predicted by theoretical calculations of color-transparency.

Journal Article↗