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F J Muñoz

Publications and source records attributed to F J Muñoz.

At least 19 recordsLinked to original sources
PubMed2001

Two isoforms of a nucleotide-sugar pyrophosphatase/phosphodiesterase from barley leaves (Hordeum vulgare L.) are distinct oligomers of HvGLP1, a germin-like protein.

Two isoforms of ADPglucose pyrophosphatase/phosphodiesterase (AGPPase) have been characterized using barley leaves (Hordeum vulgare L.). Whilst one of the isoforms, designated as soluble AGPPase1 (SAGPPase1), is soluble in low ionic strength buffers, the other, SAGPPase2, is extractable using cell wall hydrolytic enzymes or high salt concentration solutions, thus indicating that it is adventitiously bound to the cell wall. Both AGPPase isoforms are highly resistant to SDS, this characteristic being utilized to purify them to homogeneity after zymographic detection of AGPPase activity in SDS-containing gels. N-terminal and internal amino acid sequencing analyses revealed that both SAGPPase1 and SAGPPase2 are distinct oligomers of the previously designated HvGLP1, which is a member of the ubiquitously distributed group of proteins of unknown function designated as germin-like proteins (GLPs).

Amino Acid Sequence↗
PubMed2000

Seasonal changes in peripheral blood leukocyte functions of the turtle Mauremys caspica and their relationship with corticosterone, 17-beta-estradiol and testosterone serum levels.

We have studied the most representative functions of lymphocytes such as adherence to substrate, mobility directed to a chemoattractant gradient (chemotaxis), proliferative response to mitogens and antibody-dependent cellular cytotoxicity (ADCC), as well as natural killer (NK) activity in peripheral blood cells from the turtle Mauremys caspica, and the seasonal changes of these functions in both female and male animals. The plasma levels of steroid hormones were determined to study their relationship with the immune functions. Our results show high chemotaxis, lymphoproliferative response and ADCC as well as NK activity in winter when the levels of corticosterone, testosterone and 17-beta-estradiol were depleted. Proliferative responses to phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) were increased in spring correlating with low levels of corticosterone and testosterone in middle and late spring. In summer, the proliferative response was decreased but adherence, chemotaxis, ADCC and NK activity were increased, although steroid hormones showed high plasma levels. In autumn, a depletion of both the hormone levels and the immune response were found except for adherence to substrate. The immune functions studied were strikingly influenced by the seasonal cycle, which induced a different pattern of response depending on the function analyzed. Moreover, these immune cells showed a different degree of dependence on steroids in relation to the function and the season considered, suggesting the existence of other factors that modulate the immune response studied.

Animals↗
PubMed2000

The role of oxidative stress in the toxicity induced by amyloid beta-peptide in Alzheimer's disease.

One of the theories involved in the etiology of Alzheimer's disease (AD) is the oxidative stress hypothesis. The amyloid beta-peptide (A beta), a hallmark in the pathogenesis of AD and the main component of senile plaques, generates free radicals in a metal-catalyzed reaction inducing neuronal cell death by a reactive oxygen species mediated process which damage neuronal membrane lipids, proteins and nucleic acids. Therefore, the interest in the protective role of different antioxidants in AD such as vitamin E, melatonin and estrogens is growing up. In this review we summarize data that support the involvement of oxidative stress as an active factor in A beta-mediated neuropathology, by triggering or facilitating neurodegeneration, through a wide range of molecular events that disturb neuronal cell homeostasis.

Alzheimer Disease↗
PubMed2000

Murine CFTR channel and its role in regulatory volume decrease of small intestine crypts.

Cystic fibrosis (CF) is caused by mutations in the secretory Cl(-) channel CFTR (cystic fibrosis transmembrane conductance regulator). Variation in the severity of disease has been attributed to mutations in the CFTR gene that cause different degrees of dysfunction of the CFTR Cl(-) channel. However, studies of mouse models of CF indicate that the severity of intestinal pathology is not correlated with activity of the CFTR chloride channel. This observation suggests that other 'environmental' factors might be important in determining the severity of disease. In this respect, we have identified and characterised an additional cellular defect in intestinal epithelial cells of CF mice, the inability of these cells to regulate their volume after hypotonic challenge. Here, we review the function of murine CFTR as both a Cl(-) channel and as a regulator of volume-dependent homeostatic cell mechanisms.

Animals↗
PubMed2000

Primary Sjögren's syndrome in men: clinical and immunological characteristics.

OBJECTIVE: To determine the clinical and immunological characteristics of primary Sjögren's syndrome (SS) in men from a large series of unselected patients with this condition. METHODS: We studied 223 consecutive patients (204 women and 19 men; mean age at onset 53 y, range 15-87 y, mean disease duration 77 months) with primary SS visited in our units. All these patients fulfilled 4 or more of the diagnostic criteria for SS proposed by the European Community Study Group in 1993. RESULTS: Nineteen (9%) patients were men and they represent the male group described in this paper. Extraglandular manifestations during the course of their disease were present in 10 (53%) of our male patients with primary SS: articular involvement in 4 (21%) patients, interstitial pneumopathy in 3 (16%) and peripheral neuropathy in 2 (11%). ANA were positive in 13 (68%) patients, RF in 5 (31%), anti-Ro/SS-A in 3 (16%) and cryoglobulins in 1/14 (7%). When compared with women, men with primary SS presented a lower prevalence of articular involvement (21 percent; vs 46%, P=0.03, OR 0.32, CI 0.07-0.97). CONCLUSION: Although primary SS is typically a disease of middle-aged women, clinicians should note that it may be diagnosed in male patients. Except for a lower prevalence of articular involvement, we could no find any notable differences in clinical and immunological characteristics between male and female patients with primary SS.

Adolescent↗
PubMed1999

Peripheral binding site is involved in the neurotrophic activity of acetylcholinesterase.

Acetylcholinesterase (AChE) catalyses the hydrolysis of the neurotransmitter acetylcholine and it has been implicated in several non-cholinergic actions, including neurite outgrowth and amyloid formation. We have studied the trophic function of brain AChE on neuronal cell metabolism and proliferation as well as the enzyme domain involved in such effects. Low AChE concentrations (0.1-2.5 nM) stimulated neurite outgrowth and induced cell proliferation as measured by MTT reduction and [3H]thymidine incorporation. The action of AChE was not affected by edrophonium and tacrine both active site inhibitors, but it was abolished by propidium and gallamine, two peripheral anionic binding site (PAS) ligands. We conclude that the PAS domain of AChE is involved in the neurotrophic activity of the enzyme.

Acetylcholinesterase↗
PubMed1999

Age-related loss of proliferative activity of human vascular smooth muscle cells in culture.

This work studied the proliferation activity in cultures of vascular smooth muscle cells (SMC) from individuals of different ages. The cells derived from arteries of 12 donors of both sexes from 45 to 91 years of age. The main parameter considered was the 'proliferation rate' (cells grown per day in the different culture passages) taking into account the age of the donor. No significant relationship between age of the donor and the cell life in proliferation was found. On the contrary, the mean time of passage duration for reaching the maximum of proliferation as well as its 'efficiency' (maximum of proliferation rate registered/mean time of passage duration) show a statistically significant dependence on the age of the donor. Furthermore, the proliferation rate measured in each passage is statistically significant related to donor age. The regressions obtained show a similar negative slope (VC 4%). Considering the first five culture passages, the regression crosses the x-axis at the age of 105.6+/-11.7 years. This age in which no proliferative activity of human SMC would be expected lies near the limit of maximum life potential for human beings. Our results suggest that with advancing donor age there is an increasing number of senescent SMC either primarily transferred or appeared in the culture. Vascular SMC of individuals whose life is near the end would almost be all senescent and therefore show extremely low proliferation rates in the culture. If the proliferative activity of arterial SMC is a condition for atherogenesis, the proportion of senescent cells would be inversely related to the propensity of developing the atheroma because of the inability of these cells to divide.

Aged↗
PubMed1999

PC12 and neuro 2a cells have different susceptibilities to acetylcholinesterase-amyloid complexes, amyloid25-35 fragment, glutamate, and hydrogen peroxide.

This work addresses the differential effects of several oxidative insults on two neuronal cell lines, PC12 and Neuro 2a cells, extensively used as neuronal models in vitro. We measured cellular damage using the cytotoxic assays for MTT reduction and LDH release and found that acetylcholinesterase (AChE)-amyloid-beta-peptide (Abeta) complexes, Abeta25-35 fragment, glutamate and H2O2 were over 200-fold more toxic to PC12 than to Neuro 2a cells. 17alpha and 17beta estradiol were able to protect both cell types from damage caused by H2O2 or glutamate. By contrast, other insults not related to oxidative stress, such as those caused by the nonionic detergent Triton X-100 and serum deprivation, induced a similar level of damage in both PC12 and Neuro 2a cells. Considering that the Abeta peptide, H2O2 and glutamate are cellular insults that cause an increase in reactive oxygen species (ROS), the intracellular levels of the antioxidant compound, glutathione were verified. Neuro 2a cells were found to have 4- to 5-fold more glutathione than PC12 cells. Our results suggest that Neuro 2a cells are less susceptible to exposure to AChE-Abeta complexes, Abeta25-35 fragment, glutamate and H2O2 than PC12 cells, due to higher intracellular levels of antioxidant defense factors.

Acetylcholinesterase↗
PubMed1999

Neurotoxicity of acetylcholinesterase amyloid beta-peptide aggregates is dependent on the type of Abeta peptide and the AChE concentration present in the complexes.

Alzheimer's disease (AD) is a neurodegenerative disorder whose hallmark is the presence of senile plaques and neurofibrillary tangles. Senile plaques are mainly composed of amyloid beta-peptide (Abeta) fibrils and several proteins including acetylcholinesterase (AChE). AChE has been previously shown to stimulate the aggregation of Abeta1-40 into amyloid fibrils. In the present work, the neurotoxicity of different amyloid aggregates formed in the absence or presence of AChE was evaluated in rat pheochromocytoma PC12 cells. Stable AChE-Abeta complexes were found to be more toxic than those formed without the enzyme, for Abeta1-40 and Abeta1-42, but not for amyloid fibrils formed with AbetaVal18-Ala, a synthetic variant of the Abeta1-40 peptide. Of all the AChE-Abeta complexes tested the one containing the Abeta1-40 peptide was the most toxic. When increasing concentrations of AChE were used to aggregate the Abeta1-40 peptide, the neurotoxicity of the complexes increased as a function of the amount of enzyme bound to each complex. Our results show that AChE-Abeta1-40 aggregates are more toxic than those of AChE-Abeta1-42 and that the neurotoxicity depends on the amount of AChE bound to the complexes, suggesting that AChE may play a key role in the neurodegeneration observed in Alzheimer brain.

Acetylcholinesterase↗
PubMed1999

Audible pops during cyclodiode procedures.

PURPOSE: This study was conducted to determine the incidence of intraocular uveal microexplosions ("pops") during contact diode laser transscleral cyclophotocoagulation (cyclodiode) and to analyze the influence of pop occurrence on results and postoperative complications. METHODS: Cyclodiode treatment (1.5-2 W x 2 seconds over 270 degrees) was performed in 43 consecutive patients (43 eyes) with uncontrolled glaucoma who had not undergone previous ciliary ablation. Mean duration of follow-up evaluation was 12.7 months (range, 9-18 months). These eyes included 31 seeing eyes, in which intraocular pressure (IOP) reduction was indicated to preserve visual acuity (therapeutic group) and 12 blind eyes, in which IOP reduction was advisable to relieve pain (palliative group). Success was defined as a final IOP > or = 5 mmHg and < or = 21 mmHg in seeing eyes, and as the resolution of pain in blind eyes. Potential factors evaluated for intraoperative pop occurrence included patient age, gender, iris color, glaucoma diagnosis, preoperative IOP, and number of previous surgical procedures used to treat glaucoma. RESULTS: In the group receiving therapeutic treatment, mean +/- standard deviation (SD) IOP was 41.8 +/- 12.7 mmHg before surgery and 19.2 +/- 8.3 mmHg after surgery; the success rate in this group was 83.9%. In the group receiving palliative treatment, mean IOP was 55.4 +/- 13.7 mmHg before surgery and 21.1 +/- 13.4 mmHg after surgery; success rate was 83.3% in this group. Intraoperative microdisruptions occurred in 48.8% of the cases during the first laser application; 67.5% of these occurred in the superior half of the eye. No significant difference in rate of intraoperative pop was observed between patients after one cyclodiode session and those eyes that underwent additional sessions. Mean baseline IOP was significantly higher in patients with intraoperative occurrence of pops. An audible pop was more common in the group undergoing palliative treatment. Intraoperative occurrence of pops was associated with a greater severity of postoperative iridocyclitis. All patients with postoperative hyphema also had pops during surgery. No significant difference in the success rate was found between patients in whom intraoperative pops did and did not occur. CONCLUSION: Choroidal vaporization is significantly more common in patients with higher baseline IOP. Occurrence of pops also is associated with more severe postoperative inflammation and with a greater risk of postoperative hyphema.

Aged↗
PubMed1998

Estrogen protects neuronal cells from the cytotoxicity induced by acetylcholinesterase-amyloid complexes.

The senile plaques present in Alzheimer's disease (AD) are composed of a core of amyloid beta-peptide (Abeta) plus several proteins including acetylcholinesterase (AChE). Recently we found that AChE forms complexes with the Abeta peptide in vitro and that these are more cytotoxic than Abeta fibrils alone. Considering that estrogen has been reported to act as a protective agent against Abeta-induced cytotoxicity, the effect of 17beta-estradiol was studied in rat pheochromocytoma (PC12) and mouse neuroblastoma (Neuro 2a) cells exposed to either Abeta alone or AChE-Abeta complexes. Estrogen showed a powerful protective effect in response to the challenge of AChE-Abeta complexes as well as with Abeta fibrils. This was also the case for other cytotoxic agents such as glutamate and H2O2. Our results suggest a common mechanism for cellular protection by estrogen against the toxicity of both Abeta fibrils and AChE-Abeta complexes, likely avoiding the free radical apoptotic pathway.

Acetylcholinesterase↗
PubMed1998

Stable complexes involving acetylcholinesterase and amyloid-beta peptide change the biochemical properties of the enzyme and increase the neurotoxicity of Alzheimer's fibrils.

Brain acetylcholinesterase (AChE) forms stable complexes with amyloid-beta peptide (Abeta) during its assembly into filaments, in agreement with its colocalization with the Abeta deposits of Alzheimer's brain. The association of the enzyme with nascent Abeta aggregates occurs as early as after 30 min of incubation. Analysis of the catalytic activity of the AChE incorporated into these complexes shows an anomalous behavior reminiscent of the AChE associated with senile plaques, which includes a resistance to low pH, high substrate concentrations, and lower sensitivity to AChE inhibitors. Furthermore, the toxicity of the AChE-amyloid complexes is higher than that of the Abeta aggregates alone. Thus, in addition to its possible role as a heterogeneous nucleator during amyloid formation, AChE, by forming such stable complexes, may increase the neurotoxicity of Abeta fibrils and thus may determine the selective neuronal loss observed in Alzheimer's brain.

Acetylcholinesterase↗
PubMed1998

Brassinolides promote the expression of a new Cicer arietinum beta-tubulin gene involved in the epicotyl elongation.

A cDNA clone, CanTUB, encoding a putative beta-tubulin protein was isolated from a cDNA library constructed from 5-day old chickpea (Cicer arietinum) epicotyls. Analysis of its deduced amino acid sequence showed all the typical structural motifs of plant beta-tubulins. Putative sequences for autoregulation and tubulin mRNA stability, GTP and Ca2+/MAPs (microtubule-associated proteins) binding sites were present. Southern blot analysis of chickpea genomic DNA revealed that there are multiple beta-tubulin genes. The level of expression of beta-tubulin genes was correlated with the rate of growth in either seedlings and adult plants. The transcript levels of beta-tubulin genes were higher in actively elongating tissues such as etiolated epicotyls, roots and stem tissues of adult plants. Brassinolide-induced growth in chickpea epicotyls was accompanied by promotion of the expression of the gene coding for beta-tubulin.

Brassinosteroids↗
PubMed1998

Insulin stimulates collagen synthesis in vascular smooth muscle cells from elderly patients.

The process of aging results in an increase in collagen in arterial walls, but the blood levels of insulin-like growth factor 1 (IGF-1) decrease remarkably as adults age. There is an almost simultaneous increase in insulin secretion, particularly in obese individuals. It is not known if, under these hormonal conditions, the enrichment of collagen in the arterial wall is due to insulin. We studied the effect of insulin on the production of collagen in vascular smooth muscle cells (VSMC) from elderly persons with high levels of insulin secretion after blocking the insulin receptors with a monoclonal antibody. Results were compared to those without insulin receptor blockage and to those with IGF-1. Despite the inhibition of 14C-glucose uptake, insulin clearly stimulated the release of procollagen III, and increased the collagen synthesis. The hydroxyproline labelling rate from 3H-proline increased to more than twice the control values. IGF-1 is a more potent effector than insulin, but the effect of insulin on the rate of collagen production became similar to IGF-1 when the specific receptors were blocked. The results indicate that under special conditions that occur with aging, insulin interacts with nonspecific receptors in VSMC, especially IGF-1, stimulating these cells to produce collagen.

Aged↗
PubMed1998

Phenotypic changes in vascular smooth muscle cells during aging: insulin effect on migration.

We examined the mechanisms by which insulin may be atherogenic during aging. We postulated that an increase in insulin secretion during aging produces growth factor effects on vascular smooth muscle cells (VSMCs), promoting these cells to synthesize collagen and to migrate. We have previously demonstrated that insulin stimulates collagen synthesis and release in senescent VSMCs that were obtained from a human organism with high levels of insulin secretion. Using the same experimental model, we now study the effects of insulin on VSMC migration. We demonstrate that insulin has a chemoattractant effect on VSMCs which occurs through insulin binding to its own specific receptors as opposed to its effect on collagen production. Blocking the insulin receptor significantly eliminates the insulin effect on cell migration. At the same molarity, the chemotactic effect of insulin is less pronounced than that of insulin-like growth factor-1. In spite of different mechanisms, there is a remarkable correlation between the insulin effects on collagen secretion and cell migration (r2 = 97%, p < 0.0005). Our results indicate that distinct but closely related mechanisms may exist by which insulin becomes atherogenic. Our results also suggest the importance of normal aging processes in the development of atherosclerosis.

Aged↗
PubMed1998

[Blood levels of soluble ICAM-1 in patients with multiple sclerosis].

INTRODUCTION: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. The Intercellular Adhesion Molecule plays a fundamental part in the migration of T cells to the inflammed tissues. It is known that there is an increase in the expression of endothelial cells and other cells found in lesions of the central nervous system of MS patients. ICAM-I may be detected in its soluble form in serum and it is of interest to understand its behaviour in this liquid since it is easily accessible. MATERIAL AND METHODS: We studied the concentration of soluble ICAM-I in the serum of patients with MS: one group which had clinical attacks were studied whilst in remission; another had the chronic progressive clinical form and a third group had optic neuritis as the probable initial sign of the disorder. Within the different clinical forms, some patients received treatment with beta-interferon or azathioprine and others did not. RESULTS AND CONCLUSIONS: We found a significant increase in the levels of soluble ICAM-I in patients with inactive, untreated MS as compared with normal persons, with no difference found between the different clinical types.

Autoimmune Diseases↗
PubMed1997

[Primary Sjögren's syndrome: clinical and immunologic study of 80 patients].

BACKGROUND: To determine the clinical and immunologic characteristics of a large cohort of patients with primary Sjörgen's syndrome (SS) and to asses if the sex, the age at onset, the time of evolution and the immunologic pattern define different subsets with specific characteristics. PATIENTS AND METHODS: We included 80 patients (76 female and 4 male) that were prospectively studied at our Unit. All patients fulfilled the European Community criteria proposed in 1993 for the diagnosis of SS. RESULTS: Mean age of patients was 62 years with a mean disease duration of 8 years. The most frequently observed clinical manifestations were xerostomia (96%), xerophthalmia (94%) and parotidomegaly (46%). The main extraglandular manifestations were arthritis (45%), Raynaud's phenomenon (20%) and liver involvement (19%). The immunologic study showed antinuclear antibodies in 82% of patients, rheumatoid factor in 45%, anti-Ro/SS-A in 40% and anti-La/SS-B in 20%. In patients with an onset of disease before the age of 40 years, a higher prevalence of parotidomegaly, peripheral neuropathy, cutaneous vasculitis, rheumatoid factor, anti-Ro/SS-A and anti-La/SS-B antibodies was observed. A disease duration longer than 10 years was associated with a higher prevalence of pulmonary involvement and more focus of mononuclear cells in the minor salivary glands. Clinical manifestations associated to any one or more immunologic marker (rheumatoid factor, anti-Ro/SS-A and/or anti-La/SS-B) were Raynaud's phenomenon, arthritis, thyroid disease, cutaneous vasculitis and peripheral neuropathy. CONCLUSIONS: Primary SS is an autoimmune disease characterized by a marked heterogeneity in the clinical presentation and evolution, thus allowing the definition of several subsets of patients with their own clinical and immunological characteristics.

Adult↗