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Biomedical subjects

J M Ferrer

Publications and source records attributed to J M Ferrer.

At least 19 recordsLinked to original sources
PubMed2000

Use of ultrasound contrast in the diagnosis of carotid artery occlusion.

OBJECTIVE: The purpose of this study was to evaluate the use of an echo-enhancing agent in patients with carotid artery occlusion to improve the sensitivity and specificity of carotid color flow ultrasonography. METHOD: Between January 1997 and December 1998, a prospective study involving 85 cases of carotid artery occlusion in 84 patients was carried out. After a baseline duplex ultrasonography (DU) diagnosis, a second (DU) along with an echo-enhancement agent (SHU-508-A [Levovist]) study was carried out (echo enhancement ultrasonography diagnosis [DUEE]). In 82 cases, a contrast angiography was performed to confirm the diagnosis, whereas in the other three cases the diagnoses were confirmed with surgery. RESULTS: From the 85 internal carotid artery occlusions diagnosed at the initial DU examination, seven came out to be false occlusions in the DUEE examination (8,2%). There was a 100% correlation of the cases between the DUEE examination and the contrast angiography in the 82 cases in which this had been done. In three of the cases, the diagnosis was confirmed surgically because these displayed severe stenoses according to the DUEE studies in symptomatic patients, and so they required urgent treatment. CONCLUSIONS: The DUEE study is a potent diagnosis tool that allows the differentiation between true carotid artery occlusions and pseudo-occlusions.

Aged↗
PubMed2000

Electron microscopic contrast of the cytoskeleton and junctional complexes of intestinal epithelial cells by ethanolic phosphotungstic acid.

After glutaraldehyde fixation and treatment with ethanolic phosphotungstic acid (E-PTA) before plastic embedding, sections of rat large intestine showed a characteristic electron contrasting pattern in epithelial cells. The axis of microvilli, terminal web, a thin band below the luminal plasma membrane, centrioles and junctional complexes (tight junctions, adherens junctions, and desmosomes) appeared highly contrasted. In addition to protein components of microfilaments and intermediate filaments, proteins from the junctional complexes could also be implicated in the contrasting reaction with E-PTA. Mitochondrial membranes, chromatin masses, and nucleoli of enterocytes showed considerable electron density, whereas no reaction was found in the glycocalyx and mucin content of goblet cells. The clear visualization of cytoskeleton elements and junctional complexes by E-PTA contrasting represents a simple and valuable method for studies on the normal and pathological organization of these structures in epithelial cells.

Animals↗
PubMed1999

Neurologic complications associated with hepatitis C virus infection.

A series of nine patients with neurologic complications of hepatitis C virus infection is reported. Seven patients presented a combination of chronic sensory polyneuropathy, multineuropathy, and encephalopathy related to cryoglobulinemia. The noncryoglobulinemic symptoms consisted of an anterior optic neuropathy and a restless legs syndrome with small-fiber neuropathy. Corticosteroids and cyclophosphamide were useful in controlling vasculitic episodes. Interferon-alpha caused remission in half of the treated patients.

Adult↗
PubMed1999

Increased risk of unintentional dural puncture in night-time obstetric epidural anesthesia.

PURPOSE: To evaluate the experience of the operator and the time of epidural anesthesia as factors contributing to unintentional dural puncture (UDP). METHODS: In a prospective analysis of recorded cases of UDP the following variables were recorded: maternal height, weight, and weight gain, type of personnel providing epidural analgesia, number of attempts, and hour of the epidural procedure. Work time was divided into day-time (8 AM to 7 PM) and night-time (7 PM to 8 AM), according to the change of coverage of the delivery suite. Night-time was divided into first (7 PM to midnight) and second parts (midnight to 8 AM). Relative risk was used to compare the incidence of UDP among different work-times. RESULTS: A total of 1489 consecutive epidural procedures were considered. The incidence of dural puncture was 0.8% (12 cases). The relative risk was higher for night-time than day-time (risk ratio 6.33; 95% confidence interval, 1.39 to 28.80; P = 0.006). Seven cases were caused by three operators with poor expertise, and five by two skilled obstetric anesthesiologists. CONCLUSION: Operator experience and hour of procedure appear to be two important risk factors of UDP The increased risk of UDP in night-work could result from human factors such as fatigue, sleep deprivation or interruption.

Adult↗
PubMed1999

A novel nonsense mutation at Glu-631 in a Spanish family with complement component 7 deficiency.

Deficiency of the seventh component of complement (C7D) is frequently associated with recurrent neisserial infections. We report in the present study the genetic basis for C7D in a Spanish family. We used exon-specific polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) analysis as a screening step for mutations, followed by direct sequencing of the target exon. The mutation in the proband was a homozygous G-to-T transversion at nucleotide 1957, the first nucleotide of the codon GAG for Glu-631, leading to a stop codon TAG (E631X). Our result provides further evidence that the molecular pathogenesis of C7D is heterogeneous.

Adult↗
PubMed1999

A prospective study of adverse drug reactions in hospitalized children.

AIMS: There are few publications of adverse drug reactions (ADRs) among paediatric patients, though ADR incidence is usually stated to be higher during the first year of life and in male patients. We have carried out a prospective study to assess the extent, pattern and profile risk for ADRs in hospitalized patients between 1 and 24 months of age. METHODS: An intensive events monitoring scheme was used. A total of 512 successive admissions to two medical paediatric wards (47 beds) were analysed. The hospital records were screened daily during two periods (summer, 105 days and winter, 99 days), and adverse clinical events observed were recorded. RESULTS: A total of 282 events were detected; of these, 112 were considered to be manifestations of ADRs. The cumulative incidence was 16.6%, no differences being observed between periods. Although there were no differences between patients under and over 12 months of age, risk was found to be significantly higher among girls compared with boys (RR=1.66, 95% CI 1.03-2.52). The gastro-intestinal system was most frequently affected. The therapeutic group most commonly implicated was anti-infective drugs and vaccines (41.5%). The ADRs were mild or moderate in over 90% of cases. A consistent relationship was noted between the number of drugs administered and the incidence of ADRs. CONCLUSIONS: Hospitalized patients exhibited an ADR risk profile that included female sex and the number of drugs administered. No particular age predisposition was observed. The most commonly prescribed drugs are those most often implicated in ADRs in paediatric patients.

Child, Hospitalized↗
PubMed1999

CD95 expression and function on lymphocyte subpopulations in common variable immunodeficiency (CVID); related to increased apoptosis.

Apoptosis is now recognized as a central process of development and disease, and it has been proposed as one of the mechanisms that may account for the lymphopenia seen in some diseases. In this study we measured spontaneous apoptosis and CD95 expression on different cell subpopulations from CVID patients, using flow cytometric techniques. We divided our patients into two groups according to their CD4+ and CD4+CD45RA+ cell counts. Our results clearly show increased spontaneous apoptosis and CD95 expression on the CD4+ and CD4+CD45RA+ subsets from lymphopenic CVID patients compared with normal subjects and disease controls. Interestingly, our lymphopenic CVID patients presented a profound reduction in absolute counts, mainly affecting the CD4+CD45RA+ subpopulation. We also found a statistically significant direct correlation between absolute numbers of CD4+CD45RA+ T cells and spontaneous apoptosis on the same subset in CVID patients, but attempts to induce CD95-mediated apoptosis were unsuccessful despite increased CD95 expression on CD4+ T cells. These findings suggest that apoptosis could be one of the mechanisms implicated in the significant lymphopenia present in these patients.

Agammaglobulinemia↗
PubMed1998

The binding of benzopyranes to human serum albumin. A structure-affinity study.

The binding of several benzopyranes to serum albumin was studied by equilibrium dialysis at pH 7.4 in a 67 mM sodium phosphate buffer at 37 degrees C. The equilibrium data were analyzed using a computer program for curve fitting. The binding isotherm for warfarin, 4-hydroxycoumarin, 4-chromanol, coumarin, 3-acetylcoumarin, and benzoic acid can be described by two stoichiometric dissociation constants. Elimination of the 4-hydroxyl group in the coumarin chemical structures decreases the binding affinity of the compounds on the primary binding site of serum albumin, with 4-chromanol the smallest ligand which binds to seroalbumin with high affinity. Thus, the affinity of 4-benzopyranol and the 4-hydroxybenzopyranones greater than that of benzopyranones. On the other hand, elimination of the 2-oxo group in the benzopyranone chemical structures decreases affinity for the secondary binding site.

Binding Sites↗
PubMed1998

Electrophysiological and neurochemical study of the rat geniculo-cortical pathway. Evidence for glutamatergic neurotransmission.

The projection from the dorsal lateral geniculate nucleus to the primary visual cortex of the rat was studied electrophysiologically. Electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract produced three types of responses on neurons of area 17: excitation followed by inhibition, excitation and inhibition. These results extend and confirm, in adult rats, previous studies done in rat geniculate-visual cortex cocultures preparations in vitro. The role of glutamate in the neurotransmission of the rat geniculo-cortical pathway was also investigated. In a first set of experiments, the effects of kynurenate, an antagonist of glutamate receptors, on visual cortex neurons with a monosynaptic excitatory response to dorsal lateral geniculate nucleus stimulation were studied. Microiontophoresis of kynurenate in area 17 neurons selectively suppressed the excitatory response to dorsal lateral geniculate nucleus and optic tract stimulation. In a second set of experiments, the effects of electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract on the release of amino acids in the rat visual cortex in vivo were studied. Using the push-pull method, we perfused a discrete region of the visual cortex with artificial cerebrospinal fluid (CSF), and the amino acid content of the perfusates was analysed by high performance liquid chromatography (HPLC). Stimulation of either the dorsal lateral geniculate nucleus or the optic tract significantly increased glutamate release in area 17. The rest of the amino acids studied did not show significant changes. The results provide evidence for the participation of glutamate in the neurotransmission of the geniculo-cortical pathway in the rat.

Animals↗
PubMed1998

[Image processing in the primary visual cortex].

INTRODUCTION: Area 17 or the primary visual area forms the first link in the chain of cerebral analysis of a visual image. The neurones forming the primary visual cortex are characterized by the extreme precision of their connections, functional specialization and hierarchic organization. The spatial precision of the connections within the system for vision permit retinotopic representation in the visual cortex, so that each point of the retina is projected into a specific area of the cortex. The cortical neurones which analyze the characteristics of the image situated in a precise zone of the visual field are themselves organized into a basic functional unit known as a hypercolumn. Within each hypercolumn there are various columnar cell systems with receptive fields having similar characteristics. Thus, each hypercolumn is made up of multiple orientation columns, two ocular dominance columns and 'blob' regions. All these systems permit the analysis of different aspects of the image. The neurones belonging to the orientation columns are sensitive to the orientation, spatial frequency and movement of a visual stimulus; those of the 'blob' regions to colour, and the binocular neurones of the ocular dominance columns to depth. Within each column, the hierarchical pattern of neurone interconnections determines the successive appearance of cells with receptive fields having new properties.

Geniculate Bodies↗
PubMed1997

[Transitory episode of laughter as the initial symptom of an ischemic stroke].

INTRODUCTION: Pathological laughter occurs in pseudobulbar paralysis, in psychiatric disorders and as a sign of convulsions (gelastic crisis). An extremely rare form is the "fou rire prodromique' a pathological episode of laughter preceding a stroke. The pathogenesis is unknown and classically differentiated from gelastic crises. "Fou rire prodromique' has been described in subcortical ischaemic or haemorrhagic strokes, not in cortical strokes. CLINICAL CASE: We describe a patient with an ischaemic cerebrovascular accident due to embolism of the left Sylvian artery. The clinical picture started with a short episode of pathological laughter which preceded sensitive aphasia and weakness of the right limbs. CONCLUSIONS: We suggest that in the case described it is impossible to differentiate between the "fou rire prodromique' and a gelastic crisis as a first sign of an embolic cerebrovascular accident.

Aged↗
PubMed1996

Peptidase inhibitors potentiate the effects of neurotensin and neuromedin N on self-stimulation of the medial prefrontal cortex.

The purpose of this study was to examine the possible role of endogenous peptidases in the inhibition of intracranial self-stimulation (ICSS) produced by injections of neurotensin (NT) and neuromedin N (NN) into the medial prefrontal cortex (MPC) of the rat. We studied the effects on ICSS of the MPC of the administration of thiorphan and bestatin, two specific inhibitors of the peptidases that inactivate NT and NN respectively. Microinjections into MPC of thiorphan (10 micrograms) and bestatin (25 micrograms) potentiated in inhibition of ICSS produced by the intracortical administration of NT (10 nmol) and NN (20 nmol) respectively. This potentiation affected both the amplitude and the duration of the inhibition of ICSS produced by the neuropeptides. Our data indicate that endogenous peptidases are involved in the inactivation of NT and NN in the prefrontal cortex.

Animals↗
PubMed1996

Estimates of the convergence of association projections from area 17 to rostral area 18 in the cat depend on injection site size.

To estimate the degree of convergence of corticocortical projections from area 17 to the rostral part of area 18 in the cat, we injected the retrograde tracer diamidino yellow either at single or multiple adjacent sites in area 18. We measured the diameters of the individual or larger composite injections and the diameters of the labelled regions in area 17; from these values we estimated convergence factors. Small injections led to underestimates of the overall convergence of this pathway. A maximal value for convergence (about 3 mm) was obtained with larger composite injections (above about 3 mm in diameter). These results indicate that some area 17-to-18 projections may arborize widely in area 18. Their detection may require that injected tracer covers a large portion of their arbors.

Amidines↗
PubMed1996

A prospective study of adverse drug reactions as a cause of admission to a paediatric hospital.

1. A total of 512 consecutive paediatric hospital admissions of children 2 years old or less were evaluated to assess the extent and pattern of admission caused by suspected adverse drug reactions (ADRs). the proportion of suspected ADRs related to hospital admissions was 4.3%. 2. The organ-systems most commonly implicated were the central nervous system (40.5%), digestive system (16.7%), and skin and appendages (14.3%). Together, they accounted for 71.5% of admissions attributed to ADRs. The most common clinical manifestations inducing admission were convulsions (4 cases), dizziness (4), vomiting (3), and tremor, fever, itching and apnoea (2 cases each). 3. The four classes of drugs most frequently suspected in admissions due to ADRs were respiratory drugs (35%), anti-infective agents (25%), drugs active on the central nervous system (15%) and drugs used in dermatology (10%). The most common drugs related to ADRs were a combination of chlorpheniramine, diphenhydramine, phenylephrine, guaiphenesin and salicylic acid (4 cases), followed by fenoterol, adrenaline, paracetamol, DTP vaccine and antipolio vaccine (2 cases each). 4. There were no significant differences between children older and younger than 1 year (odds ratio 0.89; 95% CI 0.37-2.17) or between the sexes as regards hospital admittance due to suspected ADRs (odds ratio 1.94; 95% CI 0.72-5.42). 5. The results of this kind of study may be influenced by patterns of drug utilization. Nevertheless, the lack of specific studies of drug effects in young children makes it desirable to carry out pharmacoepidemiological studies in this age group.

Child, Preschool↗
PubMed1996

Mediation by neurotensin-receptors of effects of neurotensin on self-stimulation of the medial prefrontal cortex.

1 Intracortical microinjections of neurotensin (NT) selectively decreased intracranial self-stimulation (ICSS) of the medial prefrontal cortex in the rat. 2 To elucidate whether this effect is mediated by NT receptors or by the formation of NT-dopamine complexes, we investigated the effects on ICSS of intracortical microinjections of neurotensin (1-11), an NT fragment that forms extracellular complexes with dopamine but does not bind to NT receptors. 3 We also studied the effects of the peripheral administration of SR 48692, a selective antagonist of NT receptors, on the inhibition of ICSS produced by the intracortical administration of NT. 4 Unilateral microinjections of neurotensin (1-11) at doses of 10, 20 and 40 nmol into the medial prefrontal cortex did not change the basal ICSS rate of this area. 5 The intraperitoneal administration of SR 48692 at doses of 0.08 and 0.16 mg kg-1 30 min before microinjection of 10 nmol of NT into the medial prefrontal cortex, antagonized the inhibition of ICSS produced by the neuropeptide. 6 These results demonstrate that the inhibitory effect of NT on ICSS is mediated by NT receptors.

Animals↗
PubMed1995

Binding of coumarins to site I of human serum albumin. Effect of the fatty acids.

It is known that binding site I on human serum albumin (HSA) consists of a zone of two overlapping regions: the specific binding region represented by warfarin binding and the specific binding region represented by azapropazone and phenylbutazone binding. In this paper binding parameters to defatted HSA and to HSA with fatty acids (molar ratio of fatty acid/HSA = 4) were compared. High-affinity binding sites for warfarin, 4-chromanol, 4-hydroxycoumarin, coumarin, 3-acetylcoumarin and phenylbutazone (759,549 M-1 > Ka > 67,024 M-1) constitute binding site I on HSA. In this binding area defatted HSA can bind two molecules of warfarin, but the presence of fatty acids diminish the binding capacity of warfarin to HSA (2 > n > 1).

Biological Transport↗