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Biomedical subjects

F Marín

Publications and source records attributed to F Marín.

At least 37 records · Page 2Linked to original sources
PubMed2000

Changes in left ventricular filling pattern during dobutamine stress Doppler echocardiography.

AIMS: To study the left ventricular filling pattern during stress Doppler echocardiography and its utility in the detection of myocardial ischaemia. METHODS AND RESULTS: Fifty-seven consecutive patients underwent dobutamine stress echocardiography. The left ventricular filling pattern (E-wave velocity; A-wave velocity; E/A ratio; E-wave deceleration time) was analysed at baseline and at maximum heart rate reached. The percentage increase in these parameters from baseline to peak heart rate was also determined. Myocardial ischaemia (regional contractility worsening) was induced in 19 cases (ischaemic group) but not in 38 cases (non-ischaemic group). There were no differences between both groups at baseline. E-wave deceleration time decreased in the non-ischaemic group (197+/-63 vs. 167+/-65 ms, P=0.01) and increased in the ischaemic group (203+/-42 vs. 315+/-135 ms, P<0.0001). A percentage increase in E-wave deceleration time of >30% showed a positive predictive value of 93% and a negative predictive value of 86% for detecting ischaemia, and in the multivariate analysis it was the only Doppler parameter (P<0.0001) that predicted the induction of ischaemia. CONCLUSION: We conclude that myocardial ischaemia provokes an increase in E-wave deceleration time. Analysis of left ventricular filling could help in the identification of those cases which are positive for ischaemia.

Dobutamine↗
PubMed2000

Hindbrain patterning: FGFs regulate Krox20 and mafB/kr expression in the otic/preotic region.

Krox20 and mafB/kr are regulatory genes involved in hindbrain segmentation and anteroposterior (AP) patterning. They are expressed in rhombomeres (r) r3/r5 and r5/r6 respectively, as well as in the r5/r6 neural crest. Since several members of the fibroblast growth factor (FGF) family are expressed in the otic/preotic region (r2-r6), we investigated their possible involvement in the regulation of Krox20 and mafB/kr. Application of exogenous FGFs to the neural tube of 4- to 7-somite chick embryos led to ectopic expression in the neural crest of the somitic hindbrain (r7 and r8) and to the extension of the Krox20- or mafB/kr-positive areas in the neuroepithelium. Application of an inhibitor of FGF signalling led to severe and specific downregulation of Krox20 and mafB/kr in the hindbrain neuroepithelium and neural crest. These data indicate that FGFs are involved in the control of regional induction and/or maintenance of Krox20 and mafB/kr expression, thus identifying a novel function for these factors in hindbrain development, besides their proposed more general role in early neural caudalisation.

Animals↗
PubMed2000

[Plasma levels of insulin and leptin in patients with morbid obesity and anorexia nervosa after weight loss or gain, respectively].

The present study was conducted in order to analyze the relationship existing between leptin and insulin levels in massive weight loss and weight recovery. Thirteen patients with severe obesity, 14 patients with anorexia nervosa and 13 healthy control subjects were studied. The patients with severe obesity underwent a vertical banded gastroplasty followed by an 800 kcal/day diet for 12 weeks. They were evaluated prior to (body mass index [BMI] 51.2 +/- 8.8 Kg/m2) and after drastic weight loss (BMI 40.6 +/- 6.7 Kg/m2). Patients with anorexia nervosa were treated exclusively with nutritional therapy during 12 weeks, and they were evaluated at their lowest weight status (BMI 16.2 +/- 2.2 Kg/m2) and after weight recovery (BMI 17.9 +/- 2.3 Kg/m2). The BMI of the normal subjects was in the normal range of 20 to 27 Kg/m2 (average 22.8 +/- 2.6 Kg/m2). BMI, percentage of body fat, waist circumference, and serum levels of leptin, insulin, and C-peptide were determined in each patient and normal subject. In severely obese patients, serum leptin and insulin decreased significantly after drastic weight reduction (leptin: from 51.8 +/- 22.3 to 23.7 +/- 10.2 ng/ml; insulin: from 27.1 +/- 13.3 to 17.2 +/- 7.2 mU/ml). In patients with anorexia nervosa, the mean serum leptin levels were significantly higher after weight recovery (5.5 +/- 3.2 vs 7.6 +/- 6 ng/ml). Serum leptin in the severe obesity group correlated positively with BMI, percentage body fat and waist circumference before and after weight loss. In those patients suffering from anorexia nervosa, serum leptin correlated positively with the BMI, percentage of body fat, and waist circumference in the low weight state and after weight recovery. In addition, their serum insulin correlated with BMI and waist circumference after weight recovery. These data reveal that serum leptin concentration correlates significantly with the BMI and body fat content 1) in subjects with a range of weight and caloric intake, 2) in obese patients after drastic weight loss; 3) in anorexic patients after weight gain; and that hyper- or normoinsulinemia do not seem to have any influence on the leptin changes caused by weight loss or gain.

Adipose Tissue↗
PubMed1999

Ebf1 controls early cell differentiation in the embryonic striatum.

Ebf1/Olf-1 belongs to a small multigene family encoding closely related helix-loop-helix transcription factors, which have been proposed to play a role in neuronal differentiation. Here we show that Ebf1 controls cell differentiation in the murine embryonic striatum, where it is the only gene of the family to be expressed. Ebf1 targeted disruption affects postmitotic cells that leave the subventricular zone (SVZ) en route to the mantle: they appear to be unable to downregulate genes normally restricted to the SVZ or to activate some mantle-specific genes. These downstream genes encode a variety of regulatory proteins including transcription factors and proteins involved in retinoid signalling as well as adhesion/guidance molecules. These early defects in the SVZ/mantle transition are followed by an increase in cell death, a dramatic reduction in size of the postnatal striatum and defects in navigation and fasciculation of thalamocortical fibres travelling through the striatum. Our data therefore show that Ebf1 plays an essential role in the acquisition of mantle cell molecular identity in the developing striatum and provide information on the genetic hierarchies that govern neuronal differentiation in the ventral telencephalon.

Animals↗
PubMed1999

Widespread atypical cutaneous Leishmaniasis caused by Leishmania (L.) Chagasi in Nicaragua.

Leishmania chagasi, the causative agent of visceral leishmaniasis (VL) in the Americas, has recently been associated with atypical cutaneous leishmaniasis (ACL) in Central America; however, little comprehensive information about this disease is available. Clinical, epidemiologic, and parasitologic characteristics of 252 ACL cases and 44 VL cases in Nicaragua were analyzed. Visceral leishmaniasis is primarily associated with malnourished children less than five years of age, whereas ACL is found predominantly in children greater than five years of age and young adults. Genetically similar parasites are associated with both disease manifestations. The sand fly Lutzomyia evansi, in addition to Lu. longipalpis, may be involved in transmission of L. chagasi to humans. Our results indicate that ACL is more prevalent than previously thought, affecting up to 10% of a local population. The fact that the same parasite appears to cause both ACL and the potentially fatal visceral disease suggests that the host immune response is critical in determining the outcome of L. chagasi infection. The public health implications of the wide-spread presence of L. chagasi are discussed.

Animals↗
PubMed1998

The relationship between rhombomeres and vestibular neuron populations as assessed in quail-chicken chimeras.

The aim of this study was to evaluate the role segmentation plays in the determination of neuronal identity in the hindbrain. We focused on two specific sets of hindbrain neurons, namely, the vestibulospinal and vestibulo-ocular neurons, which comprise distinct groups that can be identified and distinguished by virtue of their axonal projection pathways. The relationship between rhombomeres and the vestibular neuron groups was assessed by a combination of quail-chicken chimeric grafting and selective retrograde axonal tracing. Individual quail hemirhombomeres were transplanted homotopically and isochronically into a chicken embryo host. Subsequently, vestibulospinal and vestibulo-ocular neurons with specific axon trajectories were labeled retrogradely with biotin-conjugated dextran-amines. The relationship between the spatial domains of the vestibular neuron groups and rhombomere-derived domains had the following features: (1) some groups were derived from single rhombomeres; (2) some groups were derived from multiple contiguous rhombomeres; (3) two groups occupied domains that could not be defined in terms of whole rhombomere lengths; (4) some groups spanning multiple rhombomeres exhibited an internal cytoarchitectonic organization that related to individual rhombomeres; and (5) some groups exhibited limited boundary violation. These results support the notion that positional information within defined domains of the neural tube provides a groundplan for the regional determination of neuronal identity and axon pathfinding, and that hindbrain segmentation contributes to this process. But they also indicate that segmentation is not the only mechanism that defines the rostrocaudal domains of neuron types. Moreover, they emphasize that the relationship between rhombomeres and neuronal determination cannot be couched simply in terms of segmental iteration or of bimeric (paired rule) specification.

Animals↗
PubMed1998

Hypofibrinolysis in atrial fibrillation.

BACKGROUND: There is a high incidence of systemic embolism in patients with chronic atrial fibrillation. A hypercoagulable state has been demonstrated, but the fibrinolytic system is rarely studied. METHODS: Plasma levels of modified antithrombin III (ATM), tissue plasminogen activator (TPA), its inhibitor (PAI-1), TPA-PAI-1 complexes and plasmin-antiplasmin complexes (PAP), d -dimer, and fibrinogen were measured in plasma from 36 patients with chronic atrial fibrillation. Fifteen patients had rheumatic mitral stenosis and 21 had nonrheumatic atrial fibrillation. Levels were compared with those found in the plasma of 20 healthy subjects. Transthoracic echocardiographic studies were done. RESULTS: Patients with atrial fibrillation had higher plasma levels of ATM, d -dimer, PAI-1, and TPA-PAI-1 complexes than controls (P <.001). The rheumatic atrial fibrillation group also showed elevated levels of fibrinogen (P <. 05). No significant differences were found in TPA and PAP. There were no differences between rheumatic and nonrheumatic atrial fibrillation. CONCLUSIONS: Atrial fibrillation shows a hypofibrinolytic state caused by elevated PAI-1 levels with no increase in PAP complex concentration. Elevated plasma d -dimer levels suggest increased intravascular thrombogenesis. This may contribute to increased risk of thrombosis.

Aged↗
PubMed1997

Family of Ebf/Olf-1-related genes potentially involved in neuronal differentiation and regional specification in the central nervous system.

Two novel mouse genes, Ebf2 and Ebf3, have been identified which show high similarity to the rodent Ebf/Olf-1 and the Drosophila collier genes. The strong conservation of the protein regions corresponding to the DNA binding and dimerisation domains previously defined in Ebf strongly suggests that Ebf2 and Ebf3 also constitute DNA sequence-specific transcription factors. Determination of the chromosomal locations of the two genes indicated that the different members of this novel mouse multigene family are not clustered. A detailed analysis of the expression of each of the three Ebf genes in the developing central nervous system revealed partially overlapping patterns with two salient features: 1) In the region extending from the midbrain to the spinal cord, the expression of the three genes correlated with neuronal maturation, with a general activation in early post-mitotic cells, followed by specific patterns of extinction also consistent with the neurogenic gradient. 2) In the forebrain area, although the patterns of expression of the Ebf genes also reflected neuronal maturation, they appeared in addition to be region specific. These data suggest that Ebf genes may be involved in the control of neuronal differentiation in the CNS and in enforcing regional diversity in populations of post-mitotic forebrain neurons.

Amino Acid Sequence↗
PubMed1996

[Heart disease in acromegaly. Study of 27 patients].

BACKGROUND: The patients with acromegaly have an increased propensity to develop cardiovascular complications. The aim of this study was to evaluate the most relevant clinic, echocardiographic and Holter recording findings in acromegaly and its correlation with the growth hormone (GH) levels and duration of the disease. PATIENTS AND METHODS: 27 patients with acromegaly were evaluated. The basal levels of GH and insulin-like growth factor 1 (IGF-1) were measured at the time of cardiological study and compared with the spontaneous GH secretion during 12-24 hours previously studied. Echocardiogram was made using complete M-mode, two dimensional and spectral Doppler ultrasound mechanical system. Additionally an standard EKG and a Holter recording were performed during 24 hours. RESULTS: There was a strong correlation between basal levels of GH and integrated concentration of GH during the study of spontaneous secretion (r = 0.92; p < 0.01). The prevalence of symptomatic cardiovascular complications in this study was 49%, including 3 patients who died for cardiovascular events. The echocardiographic study showed a high prevalence of left ventricular hypertrophy (66.7%), diastolic dysfunction (63%) and impaired systolic function (18.5%). There was no correlation between GH and IGF-1 levels and echocardiographic findings. Conversely the degree of hypertrophy was related to the duration of the disease and the presence of arterial hypertension. The diastolic function only was related with the presence of hypertension. We found supraventricular arrhythmic events and malignant premature ventricular complexes in 6 and 6 patients, respectively. The EKG showed a high fiability to detect ventricular hypertrophy but no rhythm events. CONCLUSIONS: The high prevalence of cardiovascular complications in acromegaly, most of them asymptomatic, and its clinical relevance, advise the necessity to perform systematic cardiovascular evaluation in these patients.

Acromegaly↗
PubMed1996

Scientific research on the pineal gland and melatonin: a bibliometric study for the period 1966-1994.

By means of teledischarge techniques from the database MEDLINE we selected those documents that contained in their title one or several of the following descriptors: pineal*, epiphys*, or melatonin*, in addition to the descriptor pineal-body in the MESH (Medical Subject Headings) section. A total of 7,617 original documents published between 1966 and 1994 were extracted that dealt with any aspect related with the pineal gland or its main secretary product, melatonin. The main bibliometric laws were applied: Price's Law on the increase in scientific literature, Bradford's Law on the dispersion of the scientific literature, and Lotka's Law on the author's productivity. Furthermore, we have analyzed the participation index (PaI) of the main countries within the global production, the productivity index of the authors (PI), and the number of authors/paper index. Our results demonstrate an exponential increase of the scientific literature on the pineal gland ("r" value = 0.983, in contrast with a "r" value = 0.966 after the linear adjustment). The number of publications on melatonin was less than those on other aspects of pineal research until 1991, when this situation was reversed. The journal with the largest number of original papers is Journal of Pineal Research (1st Bradford's zone) with 533 articles, followed by Journal of Neural Transmission (258) and Neuroendocrinology (221), which constituted the 2nd Bradford's zone. The total number of authors is 9,140, responsible for 23,524 authorships. 3.8% of the authors present a PI > or = 1 (large producers), and 64.9% a PI = 0 (occasional authors). Lotka's Law was widely fulfilled in this material since 10.3% of the authors are responsible of 50.2% of all the papers. The average number of authors per paper has changed from 2.29 in 1966 to 3.85 in 1994. The most productive country (during the interval between 1988-1994) was USA (PaI = 30.6), followed by Japan (7.15), United Kingdom (6.45), Germany (6.37), France (6.26), Italy (6.15) and Spain (5.34). Of the total number articles published, 86.9% are in English.

Bibliometrics↗
PubMed1996

[Percutaneous extraction of intravascular foreign bodies: a series of 38 cases].

BACKGROUND AND OBJECTIVES: Retained foreign bodies or embolization in cardiac chambers is a relatively common clinical problem. As experience was acquired, it became apparent that failure to remove such fragments could result in morbility or mortality. In the past, surgical removal was the only method available. We present our experience of percutaneous extractions of embolized foreign bodies. The technical aspects are discussed. PATIENTS AND METHODS: Twenty eight cases (age between 1 and 80 years) of cardiac and intravascular foreign bodies seen in two hospitals are reported. Seventeen were plastic catheters or fragments (two were radiotransparent), 5 guide wires in vena cava, right atrial and ventricle, pulmonary artery and abdominal aorta, 4 patients had pacemaker electrodes in the right atrium or ventricle. Stent embolization was observed in two patients. The stents were stripped from the delivery catheter and removed from iliac artery. A pigtail catheter was sometimes used to remove the fragment found in the right ventricle. In 8 cases the capture and extraction was made using a loop snare with a 0.025 inch guide J-wire device folded in half at its midsection and inserted through a long introducer, and in another 20 cases a Dormia basket system was used. In all four patients with pacemaker electrodes, simple counteraction was used with a 10 F left coronary directional atherectomy guide catheter. RESULTS: In two patients removal was impossible--in one the pacemaker electrode was caught but not retrieved because was densely adhered to the endocardium for several years; in another a guide wire was found in a child one year old--. In the other 26 patients, foreign body extraction was performed percutaneously without any complication with a basket or snare; only in one case (a radiotransparent catheter) both systems were used. CONCLUSIONS: Percutaneous removal of centrally embolized foreign bodies, cardiac or vascular, is a safe and successful procedure. The basket system needs to be used more carefully.

Adult↗
PubMed1996

[Chylopericardium after acute pericarditis].

We present an 18 year-old man with chylopericardium after acute pericarditis with severe pericardial effusion and cardiac tamponade secondary to Mycoplasma pneumoniae infection. We review the etiology, diagnostic procedures and therapeutic possibilities for chylopericardium.

Acute Disease↗
PubMed1996

[Bibliometric evaluation of the Spanish scientific output in neurosciences. Analysis of the publication with international readership between 1984 and 1993].

A bibliometric study was made of the Spanish scientific output in the Neurosciences between 1984 and 1993. The material studied was selected in accordance with the Science Citation Index (SCI) for the year 1993 (Neurosciences section) and from the journals considered to be a "priority' by the data base Excepta Medica CD: Neurosciences. The usual bibliometric rules were used: price's law of scientific literature growth, Bradford's law of scientific literature dispersal and Lotka's law of author productivity. The national participation indices (IPa) in the leading publications with an international readership, the % SUP index (% of documents included in 10% of the world top quality production), the authors/articles index, institutional contributions and the geographical origin of these were all analyzed also. Our results showed an exponential growth in the Spanish neuroscientific literature (correlation coefficient: 0.981) and increasing IPa (period 1984-1988; 0.88; period 1989-1993: 1.59). A total of 1,488 original documents were analyzed. There was an impact factor (FI) of over 3 in 20.8% of the articles, with an average FI of 2.701. The % SUP was 6.07. The journal with the largest numbers of original papers in Brain Research (Bradford's first zone) with 186 articles and the largest IPa was in the Journal of Pineal Research (8.403). The total number of authors was 2,470, total signatures of authors were 5,958 (3.04% of the authors had a productivity index (IP) > or = 1 and 57% an IP = 0. The average number of authors/article was 4.02. The origin of the articles was: University (56.77%), Hospital (26.73%) and CSIC (14.95%). Scientific production was concentrated in the CCAA of Madrid and Cataluña 55.93%, followed by Andalucia, Castilla-León and Valencia (22.57%).

Bibliometrics↗
PubMed1996

[The fibrinolytic system in patients with dilated myocardiopathy].

OBJECTIVES: To study the fibrinolytic system in dilated cardiomyopathy (DCM) patients, and the relationship between the degree of severity (NYHA degree), and the presence of complications (atrial fibrillation, intracavity thrombus, and peripheral embolism). We also analyzed the influence of the antithrombotic therapy on the fibrinolysis's proteins. PATIENTS AND METHODS: We included 18 patients, stratified in two etiologic groups: 9 with idiopathic and 9 with ethyl DCM. The fibrinolytic system was investigated through the plasma levels of antigenic and functional t-PA and PAI-1. We also carried out a venous occlusion test to investigate the fibrinolytic the fibrinolytic activity in t-PA secretion. The clinical aspects were recorded. We included 30 healthy individuals matched for age and sex, as controls. RESULTS: The antigenic levels of t-PA and PAI-1, were significantly higher in the DCM group than in the control group (p < 0.01). The venous occlusion test responses were normal. No relationship between the fibrinolytic parameters and clinical data were observed. DISCUSSION: The high levels of antigenic t-PA found in DCM patients were considered as a vascular injury marker, and a atherothrombotic risk factor. Furthermore, there is a hypofibrinolytic condition shown by a PAI-1 augmentation. In conclusion, we are prone to consider long term oral anticoagulation in the management of DCM patients.

Adult↗
PubMed1995

Morphological fate of rhombomeres in quail/chick chimeras: a segmental analysis of hindbrain nuclei.

Quail rhombomeres two to six (r2-r6) were individually grafted homotopically into the hindbrain of chick embryos at 2 days of incubation. Nine to 10 days after the operation the chimeric embryos were fixed and processed for parallel cytoarchitectural and immunocytochemical study (with an anti-quail antibody) in order to map the anatomical fate of the grafted tissue. Emphasis was placed on conventionally identified and distinct neuronal populations composing the sensory and motor longitudinal columns. Grafted rhombomeres consistently developed as complete transverse slices of the chimeric hindbrain. Interrhombomeric cell migration was either sparse or restricted to specific nuclei. The cranial nerve motor nuclei showed rhombomeric origins consistent with the patterns described in early embryos. Unexpectedly, alar r2 was found to form the auricular part of the cerebellum. As regards the cochlear nuclei, we found that nucleus angularis derives from r3 to r6, nucleus laminaris from r5 to r6, nucleus magnocellularis from r6 to r7 and nucleus olivaris superior from r5. The nuclei of the lateral lemniscus originated between r1 and r3. We also delimited the respective rhombomeric subdivisions of the sensory vestibular and trigeminal columns, both of which extend from r1 caudalwards throughout the hindbrain. There were consistently some interrhombomeric neuronal migrations inside the vestibular column, some motor nuclei and the reticular formation, involving only one rhombomere length. The pontine nuclei, which extended from r1 to r7, showed neuronal migrations that crossed several rhombomeres. On the whole, these results represent the first anatomical analysis of the mature avian hindbrain in terms of rhombomere-derived domains.

Animals↗
PubMed1995

Induction of ectopic engrailed expression and fate change in avian rhombomeres: intersegmental boundaries as barriers.

We tested the possibility of inducing ectopic expression of the gene Engrailed-2 (En-2) in the rhombomeres of the 2-days-old chick embryo. The experimental procedure consisted of grafting En-2-expressing neuroepithelium (prospective isthmocerebellum) from a quail or a mouse embryo into different rostrocaudal levels in the hindbrain of a host chick embryo. The graft replaced a given excised host rhombomere, the rostral and caudal limits of which were either also excised or left intact in different experiments. Induction of En-2 occurred in the host hindbrain, but only when the graft did not contact with host interrhombomeric boundaries and only in the alar plate of the rhombomeres immediately contacting the graft. Long survival experimental embryos showed that induced rhombomeres give rise to a cerebellar phenotype in their transformed alar plates. We thus demonstrate here a pluripotential state of the early rhombomeres as well as a possible role of the interrhombomeric limits as barriers to morphogenetic influences.

Animals↗