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Biomedical subjects

A Arribas

Publications and source records attributed to A Arribas.

18 recordsLinked to original sources
PubMed2002

Inhibitory effects of whole and parotid saliva on immunomodulators.

Based on the presence of cytokines in whole saliva and their association with resistance and susceptibility to infectious disease, the present study was designed to evaluate the diagnostic potential of a large panel of cytokines and chemokines in saliva. Despite the endogenous presence of Th1/Th2 and pro-inflammatory cytokines and several chemokines in whole and parotid saliva of most individuals tested, the detection of known concentrations of several recombinant cytokines and chemokines was inhibited immediately following their addition to each type of saliva. In contrast, purified immunoglobulins were unaffected by either whole or parotid saliva. Further studies revealed that the inhibition of immunoreactivity involved sequestration of the majority of cytokines affected and degradation of chemokines. These results suggest that absolute concentrations of cytokines/chemokines may not be fully detectable in saliva. Therefore, the diagnostic value of any cytokine/chemokine is questionable and should be evaluated independently as such.

Adjuvants, Immunologic↗
PubMed2001

[Ventricular tachycardia and cardiac hemochromatosis].

Hemochromatosis is characterized by an excessive iron deposit in different tissues. Cardiac involvement may be observed in one third of the patients due to hemochromatosis and occurs as a consequence of ferritin accumulation in the heart which on one hand induces alterations in systolic and diastolic ventricular function and on the other hand, an arrythmogenic substrate. The clinical manifestations can be indistinctly related to atrial tachyarrhythmia, ventricular tachyarrhythmia, atrio-ventricular blockade and congestive heart failure, with the first being the most frequent. We present the case of one patient with secondary hemochromatosis to repeated transfusions due to sideroblastic anemia with cardiac involvement, whose initial heart manifestations were recurrent atrial tachyarrhythmia and sustained ventricular tachycardia with syncope for which an automatic defibrillator was implanted.

Adult↗
PubMed2000

In vivo virulence of Candida albicans isolates causing mucosal infections in people infected with the human immunodeficiency virus.

Mucosal candidiasis is common in human immunodeficiency virus (HIV) infection. Susceptibility to such infections may be attributed to reduced host defense mechanisms and/or virulence of the organism. In the present study, we compared the virulence of mucosal Candida albicans isolates from HIV-infected people, with and without fluconazole-refractory infection, in established murine models of systemic and vaginal candidiasis. Compared with the mortality rate ( approximately 70%) after intravenous challenge with 2 virulent reference isolates, challenge with most clinical isolates (66%-77%) resulted in prolonged survival. In contrast, fungal burden induced by intravaginal challenge of nearly all (97%) isolates was similar to that of the virulent controls. There were no differences in in vitro growth rates for any of the isolates, and there was no association between reduced mortality and clinical failure to fluconazole, in vitro antifungal susceptibility, site of infection, or other host factors. These results suggest that virulence of C. albicans is tissue specific and is not a factor in the development of fluconazole-refractory infections in advanced HIV disease.

AIDS-Related Opportunistic Infections↗
PubMed2000

[Perforating epicardial lead: atypical evolution].

Endocarditis related to pacemaker lead is a rare complication of permanent transvenous pacing, of which the diagnosis is carried out with the presence of verrucae in echocardiography and positive blood cultures, its treatment being mixed -medical and surgical- because the isolated medical treatment is rarely successful and the lead should be extracted. We present the case of recurrent endocarditis of several years of evolution, in the which it was not possible to extract of the electrode due to the special characteristics of the patiente (epicardial lead perforating into right atrial).

Aged↗
PubMed1999

[Atrial standstill and rheumatic mitral valvulopathy].

Atrial standstill is a very rare form of bradyarrhythmia and consists of a transitory or permanent loss of the electrical and mechanical activity of the atria. We report a series of 8 patients, all of them with rheumatic valve disease (5 of them with a prosthetic valve) with symptomatic bradyarrhythmia secondary to atrial standstill, requiring an implantable pacemaker.

Aged↗
PubMed1998

Thromboangiitis obliterans (Buerger's disease) with intestinal involvement--a case report.

Thromboangiitis obliterans (TAO) or Buerger's disease is a nonatherosclerotic vascular disease of unknown etiology that occurs almost exclusively in young male tobacco users. The involvement of the medium-sized and small arteries and veins leads to ischemic complaints and trophic changes in the limbs. The authors report a case of Buerger's disease in a 29-year-old man, a heavy smoker, affecting the lower limbs and mesenteric vessels.

Adult↗
PubMed1997

Control of early cell death by BDNF in the chick retina.

The developing chick retina undergoes at least two discrete periods of programmed cell death. The earlier period coincides with the main onset of neuron birth and migration (embryonic day 5-7), whereas the latter one corresponds to the well-documented process of retinal ganglion cell death following tectal innervation (embryonic day 10-14; Rager, G. H. (1980) Adv. Anat. Embryol. Cell Biol. 63, 1-92). In the early period, apoptosis is induced by nerve growth factor (NGF) acting via its p75 receptor (Frade, J. M., Rodríguez-Tébar, A. and Barde, Y.-A. (1996) Nature 383, 166-168). Here, we show that the application of brain-derived neurotrophic factor (BDNF) to chick embryos in ovo prevented retinal cell death in the early period, whereas exogenously applied NGF and neurotrophin-3 had no such effect. The addition of BDNF to embryos resulted in about 70% increase in the number of retinal ganglion cells in both E6 and E9 retinas relative to controls. BDNF is first expressed in both the pigment epithelium and neural retina of embryonic day 4 embryos, and at the same stage of development, its TrkB receptor is expressed in the neural retina. Our data indicate that early cell death is an important process in the neurogenesis of retinal ganglion cells and is regulated by locally produced BDNF.

Animals↗
PubMed1994

Role of neurotrophins in the control of neural development: neurotrophin-3 promotes both neuron differentiation and survival of cultured chick retinal cells.

The effects of neurotrophins brain-derived neurotrophic factor and neurotrophin-3 on cultured dissociated cells from chick retina were studied at several embryonic ages from day 4 to day 13. Precursor cells from days 4-7 retinas proliferated in vitro and, after 20 h in culture, a proportion of them underwent spontaneous differentiation, as judged by both [3H]thymidine uptake and acquisition of neuronal morphology and neuron-specific markers. Brain-derived neurotrophic factor did not affect neuronal differentiation, although this factor supports survival of differentiated retinal ganglion cells [Rodríguez-Tébar et al. (1989) Devl Biol. 136, 296-303]. However, in cultures from young undifferentiated retinas, neurotrophin-3 produced up to a 2.5-fold increase in the number of [3H]thymidine-positive neurons, i.e. those that in vitro replicated their DNA. Moreover, in older retinas, neurotrophin-3, like brain-derived neurotrophic factor, supported the survival of differentiated retinal ganglion cells over a short developmental period. This effect was negligible at embryonic day 5, maximal at day 9, decreased at day 11 and was absent at embryonic day 13. Neurotrophin-3 also supported the survival of a population of amacrine neurons. This effect was modest at embryonic day 9, and increased at days 11 and 13. Our results show that, whereas the action of brain-derived neurotrophic factor is restricted to differentiated neurons, neurotrophin-3 exerts two distinct successive actions on retinal cells in vitro: first, this factor promotes either differentiation of neuroepithelial cells or maturation of recently differentiated neurons, and later in development, this factor supports the survival of differentiated retinal ganglion and amacrine cells but only during a discrete post-differentiation period.

Animals↗
PubMed1994

[The "arrhythmic pattern": a new method with prognostic significance in myocardial infarct].

OBJECTIVES: To establish a score or arrhythmic pattern for the prediction of long-term cardiac deaths on patients who have survived to the first acute myocardial infarction. PATIENTS AND METHODS: We studied prospectively 200 patients that survived at a first myocardial infarction and in whom ambulatory ECG monitoring during 24 hours between days 7th and 18th (mean 12th) from the infarction was performed. The mean follow-up time was 51 +/- 18 months. The number and type of ventricular arrhythmias were analyzed and a score was measured, accordingly with Castellanos and Lown's classifications. An "arrhythmic pattern" or "total punctuation" was defined and compared among two groups: group 1 > 65 points and group 2 < 65 points. RESULTS: The differential characteristics of both groups were: age (60 +/- 9 versus 56 +/- 10 years old; p = 0.004); hypertension (63% versus 29%; p < 0.001); clinic stage II-III (23% versus 11%; p = 0.02); echocardiographic ejection fraction (45 +/- 11% versus 50 +/- 10%; p = 0.04); positive exercise testing (73% versus 56%; p = 0.01); arrhythmias on the exercise test (15% versus 25%; p = 0.006). The long-term cardiac mortality was 25% versus 6% (p = 0.01), with an incidence of sudden death of 11% versus 3% (p < 0.05). Specificity, sensibility, positive predictive value and negative predictive value (reference cut point of 100) were 94, 65, 71 and 91%, respectively. CONCLUSIONS: The use of a score of arrhythmic pattern may identify 2 groups of patients with different clinic profiles that probably justify a different long-term prognosis after a first acute myocardial infarction.

Cardiac Complexes, Premature↗
PubMed1993

Neurotrophin-3 receptors in the developing chicken retina.

Neurotrophin 3 (NT-3) had specific high-affinity receptors (HNT-3R) in the developing chick retina at all ages between embryonic day (E) 4 and E14. The affinity of HNT-3R for 125I-NT-3 did not change with the developmental state. A dissociation constant (kd) of 13 pM was obtained. However, the amount of HNT-3R appeared to be developmentally regulated; the number of receptors/cell increased from E4 up to E6-7 (coinciding with the main onset of neuronal differentiation), then decreased until E9 and increased again by E12, when all retinal cells were differentiated. Kinetic and cross-linking experiments showed that HNT-3R from two prototypical developmental ages, E7 and E14, were different. E7 and E14 HNT-3R could be distinguished from each other on the basis of different inhibition patterns of 125I-NT-3 binding in the presence of nerve growth factor or brain-derived neurotrophic factor. Chemical cross-linking of increasing concentrations of 125I-NT-3 to its receptors showed (a) one 100-kDa band corresponding to neurotrophin low-affinity receptors in both E7 and E14 cells; (b) one 130-kDa band also present in both E7 and E14 cells. Densitometric measurements showed that this 130-kDa band behaved as HNT-3R in E14 cells (kd approximately 10 pM) but not in E7 cells (kd > or = 0.2 nM). Furthermore, the 130-kDa band in both E7 and E14 retinal cells displayed a trk-like immunoreactivity. Our data show that, in neurons, one particular neurotrophin may induce different actions mediated through distinct and specific receptors.

Animals↗
PubMed1993

Coronary steal syndrome.

A patient who suffered recurrent myocardial ischaemia and cerebrovascular symptoms 56 months after a quadruple coronary bypass is reported. Three coronary arteries had been bypassed using reversed saphenous vein and the other using the left internal mammary artery (IMA). Coronary angiography demonstrated patency of al bypasses but the presence of an obstruction of the left subclavian artery proximal to the origin of the left IMA, with angiographic criteria of the steal syndrome. The patient's symptoms were relieved by bypass from the left common carotid artery to the distal left subclavian artery. The pathophysiology, diagnosis, prevention and treatment of coronary steal syndrome are discussed.

Aged↗
PubMed1989

[Asymptomatic common truncus arteriosus in a 25-year-old patient with paroxysmal tachycardia and truncal valve insufficiency].

We present an adult patient (25-years old), free of symptoms with a congenital heart disease very infrequent and survival to adulthood is exceptional, the truncus arteriosus. Who entered to the Emergency Care Unit because of paroxysmal tachycardia. We describe the case with special reference to echocardiographic findings and we detached the rarity of this congenital heart disease in adulthood.

Adult↗