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Biomedical subjects

F Díaz

Publications and source records attributed to F Díaz.

At least 19 recordsLinked to original sources
PubMed2006

Autologous bone-marrow mononuclear cell implantation in patients with severe lower limb ischaemia: a comparison of using blood cell separator and Ficoll density gradient centrifugation.

Different studies have provided evidence that implantation of bone-marrow mononuclear cells (BM-MNC) into ischaemic limbs can improve tissue vascularization. Based on these results we performed a pilot study in patients with critical lower limb ischaemia to assess efficacy and safety of implantation of autologous BM-MNC. The amount and efficacy of BM-MNC purified either by an automated method or by a manual procedure were compared. Twelve patients with severe unilateral lower limb ischaemia were entered into this study. They were randomly assigned to be injected with BM-MNC sorted on a blood cell separator or isolated by density gradient on Ficoll-Hypaque. BM-MNC were implanted into the ischaemic legs. Patients were monitored with resting ankle-brachial pressure index (ABI), arterial oxygen saturation (SaO(2)), pain-free walking time and rest pain scale evaluation. The automated and manual methods used for mononuclear cell separation gave results not significantly different. Monitored variables improved in both groups. Improvement of ischaemic condition persisted during 24 weeks follow-up. Limb salvage was achieved in five cases. Our results indicate that BM-MNC implantation into ischaemic limbs is a practical, safe and effective method that may significantly contribute to the management of patients with limb ischaemia. The Ficoll method is a simple and effective procedure for BM-MNC concentration that may be useful, mainly in hospitals without sophisticated facilities.

Aged↗
PubMed2006

Evaluation of voice pathology based on the estimation of vocal fold biomechanical parameters.

Voice disorders are a source of increasing concern as normal voice quality is a social demand for at least one third of the population in developed countries in cases where voice is an essential resource in professional exercise. In addition, the growing exposure to certain pathogenic factors such as smoking, alcohol abuse, air pollution, and acoustic contamination, and other problems such as gastro-esopharyngeal reflux or allergy as well as aging, aggravate voice disorders. Voice pathologies justify the assignment of larger resources to prevention policies, early detection, and less aggressive treatments. Traditional pathology detection relies on perceptive evaluation methods (GRABS), acoustic analysis, and visual inspection (indirect laryngoscopy, and modern fibro-endo-stroboscopy). This article describes a method for voice pathology detection based on the noninvasive estimation of vocal cord biomechanical parameters derived from voice using specific signal processing methods. Preliminary results using records from patients showing four frequent causes of voice pathology (nodules, polyps, chronic laryngitis, and Reinke's edema) are given. The results show that the alteration (distortion, unbalance, or deviation) of cord biomechanical parameters may serve as an indicator of pathology. Statistical methods based on hierarchical clustering and principal component analysis reveal that combining biomechanical estimates with classic perturbation parameters increases the accuracy of acoustic analysis, improving the detection of voice pathology. This research could open new possibilities for noninvasive screening of vocal fold pathologies and could be used in the implantation of e-health voice care services.

Biomechanical Phenomena↗
PubMed2006

Modulation of the anti-inflammatory interleukin 10 and of proapoptotic IL-18 in patients with chronic hepatitis C treated with interferon alpha and ribavirin.

The aim of this work was to analyse apoptosis rate, measured by the serum levels of proapoptotic interleukin (IL)-18 and of soluble Fas (sFas), as well as of anti-inflammatory IL-10, in patients with chronic hepatitis C, at baseline and after treatment with interferon alpha and ribavirin. Twenty-seven patients with biopsy-proven chronic hepatitis C were studied, at baseline and after treatment with interferon alpha (21 cases) or pegylated interferon (6 cases) plus ribavirin. A group of 15 healthy sex- and age-matched individuals was selected as control. Serum concentrations of sFas, IL-10 and IL-18 were determined by ELISA in sandwich. The relationship of these molecules to necro-inflammatory and fibrotic activity was evaluated. Evolution of the serum concentrations of these molecules was analysed after treatment. Significantly increased serum concentrations of sFas were detected in patients with chronic hepatitis, compared with controls. Levels of this molecule were significantly correlated with necroinflammatory activity. Likewise, concentrations of IL-10 were significantly increased in the group of patients, compared with controls. Treatment with interferon and ribavirin induced a significant decrease of IL-18 concentration independently of the viral response. In contrast, levels of sFas decreased only in those patients with sustained response to therapy. Finally, baseline levels of IL-10 were significantly increased in patients without response to treatment, compared with those with sustained response, but the concentration did not change with the treatment. Increased serum levels of IL-10 are a negative prognostic marker of response to hepatitis C treatment. A significant decrease of apoptotic rate, as determined by sFas, can be expected in patients with a response to therapy.

Adult↗
PubMed2005

Influence of gonadal steroids on the glial fibrillary acidic protein-immunoreactive astrocyte population in young rat hippocampus.

It is known that expression of glial fibrillary acidic protein (GFAP) as an astrocyte-specific marker can be regulated by levels of circulating gonadal steroids during postnatal development. In addition, astrocytes play an important role in the physiology of the hippocampus, a brain region considered sexually dimorphic at the neuronal level in rodents. To evaluate the contribution of glial cells to gender-related differences in the hippocampus, we estimated the number of GFAP-immunoreactive (GFAP-IR) astrocytes in the hippocampus (CA1 and CA3 areas, dorsal and ventral regions) of male and female rats aged 30 days. Groups of 30-day-old masculinized females (TP-females; injected with testosterone propionate at birth) and feminized males (FLU-males, castrated and treated with flutamide, an androgen receptor antagonist) were included to assess the effects of gonadal hormones on these hippocampal astrocytes. Using the optical fractionator method, the total number of GFAP-IR cells found in CA1 and CA3 areas was significantly higher in males compared to that in age-matched females. This numerical pattern was reversed in TP-females and FLU-males in both hippocampal areas. In addition, more GFAP-IR cells were found in dorsal hippocampus than in the ventral region in the CA1 area from all experimental groups, whereas this result was found in the CA3 area from males and TP-females. Our results suggest an essential contribution of gonadal hormones to gender differences found in the astrocyte population of the rat hippocampus during development.

Analysis of Variance↗
PubMed2005

In vitro genotoxic evaluation of three alpha-asarone analogues.

alpha-Asarone has shown a significant capacity to reduce the level of lipids, including cholesterol. However, several toxic and genotoxic studies have determined that its use may pose a risk to human health. Therefore, a series of compounds structurally analogous to alpha-asarone were prepared in order to maintain the same pharmacological properties but with low toxicity. In this study we evaluated the potential of three alpha-asarone analogues to induce mutagenicity using the Ames test (strains TA98 and TA100 in the presence of metabolic activation), as well as the induction of sister chromatid exchanges (SCE) in cultured human lymphocytes. The tested compounds were: 1-(2,4,5-trimethoxyphenyl)propan-1-one (D1), 1-(2-chloro-4,5-dimethoxyphenyl)propan-1-one (D2), and 1-(4,5-dimethoxy-2-nitrophenyl)propan-1-ol (D3). The results in the first assay showed no mutagenic effect for the three tested analogues; in the TA100 strain, certain cytotoxicity did appear in the case of D2 and D3 only at high concentrations. In regard to the SCE assay, compounds D1 and D2 presented no statistical differences in comparison with the control culture values; however, the high dose of D3 (300 microg/ml) produced a significant increment in SCE (68% above the control value). With respect to the mitotic index and the cellular proliferation kinetics, we observed a reduction when compounds D2 and D3 were used at the higher concentrations. Our results encourage further preclinical studies of these compounds in both in vitro and in vivo models (particularly for analogues D1 and D2), to determine their toxicological profile and establish the possibility of using them in humans.

Allylbenzene Derivatives↗
PubMed2005

Adhesion molecules as a prognostic marker of liver cirrhosis.

OBJECTIVE: Endothelial activation plays an active role in modifications of the circulatory status of cirrhotic patients. Soluble endothelial adhesion molecules, induced by pro-inflammatory cytokines, could be considered markers of endothelial activation. Their role in the natural history of cirrhosis and portal hypertension has not been reported. Our objective was to analyze the prognostic value of soluble adhesion molecules in cirrhotic patients. MATERIAL AND METHODS: Serum concentrations of soluble CD14, soluble receptors of tumor necrosis factor alpha and adhesion molecules ICAM-1 (intercellular adhesion molecule-1) and VCAM-1 (vascular cell adhesion molecule 1) as well as mean blood pressure, plasma renin activity, aldosterone, vasopressin and norepinephrine concentrations were determined in 64 cirrhotic patients (Child-Pugh class: A 48.4%, B 34.4%, C 17.2%), without any evidence of infection, and in 25 healthy controls. Patients were followed-up for a mean of 36.4 (range 6-60) months. RESULTS: Increased concentrations of soluble CD14, tumor necrosis factor receptors and ICAM-1 and VCAM-1 were detected in cirrhotic patients when compared with healthy controls. Tumor necrosis factor receptors and adhesion molecule concentrations were both significantly higher in advanced phases of cirrhosis (Child Pugh class C and B versus A). Fifteen patients died as a related consequence of liver cirrhosis. Multivariate analysis demonstrated that Child-Pugh score and serum levels of tumor necrosis factor receptor I and ICAM-1 were associated with mortality. CONCLUSIONS: In addition to the classic factor implicated in mortality (Child-Pugh class), alterations in inflammation-related components and soluble adhesion molecules, as representatives of hemodynamic alterations, are of prognostic significance in cirrhotic patients.

Aged↗
PubMed2005

A randomized controlled trial to test an HIV-prevention intervention for Latino gay and bisexual men: lessons learned.

At the time of this writing, no randomized controlled trial (RCT) of an intervention to reduce unsafe sex among Latino gay and bisexual men (LGBM) had been published. We report the results of an RCT conducted in New York City in which 180 LGBM were assigned either to an intervention developed specifically for this population or to a wait-list control group. The intervention was based on empowerment theory and used factors identified in prior research as determinants of unsafe sex. By eligibility criteria, all men had engaged in unprotected anal intercourse (UAI) within two months of the baseline assessment. At first (two months) and second (six months later) follow-up assessments, approximately half of the men in the experimental group reported no UAI. Yet, a similar proportion of the control group also reported no UAI. Baseline data indicate that although the men had been the subject of social oppression and sexual prejudice (homophobia), they did not feel disempowered, externally controlled or fatalistic, and they reported self-efficacy and intentionality to enact safer sex. Lessons learned are discussed, as well as notes of caution for future research employing a similar conceptual framework.

Adolescent↗
PubMed2005

Effects of a non-selective beta-blocker on adult rat anterograde axonal transport and retinal ganglion layer after increased intraocular pressure.

The aim of this study was to examine the effects of timolol in an experimental model of elevated intraocular pressure (IOP). Three episcleral veins of rats with normal IOP were cauterized. Three months later we examined the effects on anterograde axonal transport from the retinal ganglion cells (RGCs) to the superior colliculus (SC) as well as on the number of neurons in the retinal ganglion layer (RGL). These parameters were also studied in a group of rats submitted to treatment with timolol after confirming that their IOP was still raised after two weeks. After the surgical procedure, the mean IOP of the experimental eyes increased to 33.5+/-1.06 mmHg (1.25 fold compared to the control group) and three months later the IOP remained significantly elevated; however, after a long period of treatment with timolol the IOP was 14.05+/-0.81 mmHg, similar to that of the control group. In the group with normal IOP, labelling with horseradish rabbit peroxidase (HRP) at 120 minutes and 24 hours postinjection showed continuous staining from the retina to the SC. In the experimental group the optic nerve head (ONH) was completely negative, although in the group treated with timolol there was partial block of axonal transport in the ONH, in which the staining was slightly more intense. The number of neurons in the RGL, counted by immunohistochemical labelling with Neu-N, showed that in eyes with normal and elevated IOP there were 423+/-11 neurons/mm(2) and 283+/-10 neurons/mm(2), respectively. After treatment with timolol the number of neurons (331+/-10 cells/mm(2) increased compared with elevated IOP eyes, although the number did not reach that of the control group. These results indicate that treatment with timolol, started two weeks after the surgical procedure, was partially neuroprotective because the loss of neurons in the RGL was lower than in untreated animals, though not sufficient to re-establish normal axonal transport.

Adrenergic beta-Antagonists↗
PubMed2005

[Laparoscopic approach for treatement of gastroesophageal reflux in newborns and infants with severe respiratory disorders. When to indicate it?].

Gastroesophageal reflux (GER) is a common finding in the newborn period, which is in general well tolerated, and tends to resolve spontaneously at about 18 months of age. However, a small number of children will present important respiratory manifestations (aspiration and apneic episodes), or increase in the manifestations of pre existing conditions (tracheomalacia, laryngomalacia), which can produce life threatning events. Ph monitoring does not completely discard the possibility of GER and the use of prokinetic drugs, in association with other drugs to protect the esophagus do not prevent serious consecuences produced by reflux to the airway. In this report six children with severe airway disease and marked GER, with no response to initial medical treatment required laparoscopic fundoplication. They have all resolved their airway disease, and are currently well. The laparocopic technique for fundoplication of small children seems to be a secure, well tolerated and definitive treatment in the hands of trained surgeons.

Gastroesophageal Reflux↗
PubMed2004

Ultrastructural and quantitative age-related changes in capillaries of the dorsal lateral geniculate nucleus.

An ultrastructural and quantitative study of age-related changes in the capillaries of the dorsal lateral geniculate nucleus was carried out using male Wistar rats aged 3, 24, and 28 months. The most important structural changes were found in the basal lamina: thickenings either homogeneously distributed or in specific points; spurs towards the astrocyte sheath; and osmiophilic membrane-like inclusions located within the basal lamina. Endothelial cells and pericytes showed an increase in inclusions and dense bodies in the cytoplasm. The quantitative study showed that the most pronounced alteration was the thickening of the basal lamina, which existed at 24 months. Later, at 28 months, thinning of the endothelial cells was observed together with an increase in mitochondria size and the number of pinocytic vesicles. These changes could be an endothelial cell response to compensate for the increasing transport difficulties caused by the thickening of the basal lamina. The progressive age-related changes observed in the structure of the capillaries might have an effect on the regulation of blood and brain tissue exchanges, and thus might contribute to the development of degenerative alterations in surrounding aging neurones.

Age Factors↗
PubMed2004

Excision and V-Y plasty reconstruction for giant condyloma acuminatum.

BACKGROUND: Condyloma acuminata is the most common anorectal lesion in patients infected with human immunodeficiency virus (HIV). Surgical treatment can be challenging in cases where the size and extension into the anal canal make individual excision impossible. These patients require large resections and reconstruction using grafts or local flaps. METHODS: Six patients were treated for giant perianal condylomas between 1999 and 2001. Four patients were HIV-positive, and were selected for surgical intervention after achieving a T4 count >350 and low viral replication. In 5 cases, the lesions were circularly resected up to the pectinate line and the defect was reconstructed using a bilateral V-Y plasty. In the remaining case, fulguration was possible on one side and a unilateral V-Y plasty was performed. RESULTS: There were no infections or healing delays in this series, and the functional and aesthetic results are satisfactory. CONCLUSION: V-Y plasties are a valid method for perianal reconstruction after resection of giant anal condyloma, with good results in selected patients with HIV infection.

Adolescent↗
PubMed2003

Large changes in Pluto's atmosphere as revealed by recent stellar occultations.

Pluto's tenuous nitrogen atmosphere was first detected by the imprint left on the light curve of a star that was occulted by the planet in 1985 (ref. 1), and studied more extensively during a second occultation event in 1988 (refs 2-6). These events are, however, quite rare and Pluto's atmosphere remains poorly understood, as in particular the planet has not yet been visited by a spacecraft. Here we report data from the first occultations by Pluto since 1988. We find that, during the intervening 14 years, there seems to have been a doubling of the atmospheric pressure, a probable seasonal effect on Pluto.

Journal Article↗
PubMed2003

Blood pressure measurement in an ambulatory setting: concordance between physician and patient self-measurement.

The aim of this study was to determine concordance between physician and patient blood pressure (BP) measurements in an ambulatory setting. A diagnostic intervention cross-sectional study using a convenience sample was employed. A total of 106 hypertensive patients were included in the study. Patients who were unable to perform their self-measurement or those with cardiac arrhythmia were excluded. BP was determined nine times in each subject in the medical office in a randomised order: BP was taken three times by the physician using a mercury sphygmomanometer (SPH-Hg), three times by the physician using a validated, automated oscillometer (Omron HEM 705 CP), and three times by the patient himself with the same device. The intraclass correlation coefficient was calculated. In all, 59 women and 47 men aged 65.7 (10) years were analysed. Mean BP measurements for the physician using the mercury sphygmomanometer, the physician using the Omron, and the patient using the same device were: 136 (15.8)/80 (11), 137 (17.9)/80 (10), and 139* (17.6)/80 (10) mmHg, respectively. BP control was 48.1, 48.1, and 36.8*% (*P < 0.05), respectively. Intraclass correlation coefficients for systolic/diastolic pressures were: 0.77/0.65 (physician-sphygmomanometer Hg, physician-Omron; P < 0.001), 0.75/0.64 (physician-sphygmomanometer Hg, patient-Omron, P < 0.001), and 0.83/0.83 (physician-Omron, patient-Omron; P < 0.001). In conclusion, the three types of measurement in the medical office were significantly concordant. Patient office self-measurement showed a tendency to increase systolic BP and worsen BP control.

Blood Pressure Determination↗
PubMed2003

Dose- and time-dependent effects of 17beta-oestradiol on insulin sensitivity in insulin-dependent tissues of rat: implications of IRS-1.

Numerous studies have suggested that ovarian hormones are able to modulate insulin sensitivity, but their exact role remains unclear. We have investigated whether different doses of 17beta-oestradiol mediate changes in insulin sensitivity and if these changes could be related to modifications of insulin receptor substrate-1 (IRS-1). Female rats were ovariectomized and later separated into three groups: untreated; treated with a dose of 17beta-oestradiol sufficient to reproduce gestational plasma concentrations of 17beta-oestradiol (group E); and treated with a dose 100 times greater than that given to group E (group E2). A euglycaemic-hyperinsulinaemic clamp was used to measure insulin sensitivity. Changes in IRS-1 were analysed by Western blotting and RT-PCR assays. In group E we found a decrease in insulin sensitivity between days 11 and 16 of treatment as in late gestation, whereas in the untreated group and group E2, development of insulin resistance was observed throughout the treatment. In contrast, whereas in group E2 insulin resistance throughout the hormonal treatment was related to diminished expression and phosphorylation of IRS-1, in group E the decrease in insulin sensitivity between days 11 and 16 of treatment was not related to a decrease in IRS-1 expression. Our results suggest that the effects of oestradiol on insulin sensitivity were dose-dependent and that the insulin resistance associated with a high dose of 17beta-oestradiol was related to downregulation of IRS-1 expression.

Animals↗
PubMed2002

Systemic lupus erythematosus associated with acute parvovirus B19 infection.

Acute parvovirus B19 infection has been implicated in the pathogenesis of several autoimmune conditions, including systemic lupus erythematosus. Viruses, including human parvovirus B19, may trigger bouts of systemic lupus erythematosus in genetically susceptible individuals. Herein, we report on two patients who developed systemic lupus erythematosus associated with acute parvovirus B19 infection and discuss the possible pathogenetic mechanisms implicated.

Acute Disease↗
PubMed2002

Effects of pregnancy on insulin receptor in liver, skeletal muscle and adipose tissue of rats.

The mechanism responsible for insulin resistance during pregnancy remains unclear. Considerable evidence indicates that the insulin receptor plays an important role in insulin sensitivity. It seems possible that the hormonal milieu during gestation could have an effect on the insulin receptor. In the present study, measurements of tyrosine phosphorylation and protein content of the insulin receptor and expression of its gene in liver, skeletal muscle and adipose tissue indicate that during pregnancy significant changes occur in these parameters. We found that at the end of early gestation (day 10), muscle and adipose tissue are very sensitive to insulin action because the amount, phosphorylation and gene expression of insulin receptor is higher than in late gestation (days 15-20), while the tissue which is most sensitive to insulin action in late gestation is the liver. Our hypothesis is that these results are connected with changes in the concentrations of estradiol and progesterone observed during pregnancy. In conclusion, our previous and present findings seem to demonstrate that the different concentrations of gestational hormones play an important role in insulin sensitivity in this period and that each tissue responds in the most appropriate manner to guarantee the gestation in its entirety.

Adipose Tissue↗
PubMed2002

[Dominant autosomal cerebral arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). A review].

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a familial condition caused by a mutation of the Notch3 gen in chromosome 19. Accumulation of osmiophilic granular material (GOM) on the middle layer of small and medium-sized cerebral arteries leads to progressive narrowing of the blood vessels. As a result, clinical findings include migraine, cerebrovascular ischemic events, vascular dementia and a number of neuropsychiatric disorders associated to an extensive leukoencephalopathy readily shown by MRI studies. GOM deposits, however, are systemic and maybe shown ultrastructuraly on skin vessels by means of a biopsy. Detection of mutations of the Notch3 gen by molecular genetics may also allow accurate diagnosis during life. So far, there is no effective treatment for this disorder.

Adult↗