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Biomedical subjects

F J Muñoz

Publications and source records attributed to F J Muñoz.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1997

Antibodies to thromboplastin in systemic lupus erythematosus: isotype distribution and clinical significance in a series of 92 patients.

We determined the prevalence and relationship with clinical manifestations of antibodies to thromboplastin (aTP) in 92 patients with systemic lupus erythematosus (SLE). Thirty-two (35%) patients had aTP: 13 (14%) were positive for IgG aTP, 13 (14%) for IgM aTP, and 6 (7%) for both. Patients with aTP had an increased incidence of thrombosis (p = 0.01), thrombocytopenia (p < 0.001), hemolytic anemia (p < 0.001), and fetal losses (p = 0.03). When the IgG and IgM aTP isotypes were analysed separately, the IgG aTP were found to be associated with thrombosis (p < 0.001), thrombocytopenia (p < 0.001), and fetal losses (p = 0.02). The IgM aTP were associated with hemolytic anemia (p < 0.001). A correlation was found between the titers of aTP and those of anticardiolipin antibodies, in both IgG (p < 0.01, r = 0.6) and IgM (p < 0.01, r = 0.64) isotypes, and between the titers of IgG aTP and the diluted Russell's viper venom time used to detect the lupus anticoagulant (p < 0.001, r = 0.42). This test is a reliable, reproducible and sensitive assay for the detection of antiphospholipid antibodies, specially in those patients under anticoagulant therapy.

Adolescent↗
PubMed1997

Two growth-related organ-specific cDNAs from Cicer arietinum epicotyls.

Two cDNAs, CanST-1 and CanST-2, encoding two different growth-related organ-specific sequences have been isolated from a cDNA library from growing epicotyls of Cicer arietinum. An intriguing property of these two clones is the presence in their coding region of a repeated sequence which is highly conserved except for the number of repeats. The corresponding genes of CanST-1 and CanST-2 encode for proteins related to elongation processes. CanST-1 and CanST-2 are up-regulated during epicotyl growth, the transcript levels of both clones decrease when the growth of epicotyls is inhibited by several treatments and their expression increases when epicotyls resume growth. Furthermore, clones CanST-1 and CanST-2 are tissue-specific and are only expressed in epicotyls, mesocotyls, roots and stem tissues whose cells undergo elongation processes. Neither clone was found to be expressed in other organs such as cotyledons, leaves, flowers, pods and immature seeds. The results of auxin (IAA) and brassinolides (BR) treatments suggest that the processes in which the proteins encoded by CanST-1 and CanST-2 are involved are not mediated by these hormones.

Amino Acid Sequence↗
PubMed1997

Hepatitis C virus infection in 'primary' Sjögren's syndrome: prevalence and clinical significance in a series of 90 patients.

OBJECTIVES: To determine the prevalence and clinical significance of hepatitis C virus (HCV) infection in a large cohort of patients with "primary' Sjögren's syndrome (SS). METHODS: 90 consecutive patients (83 female and seven male) were included, with a mean age of 62 years (range 31-80) who prospectively visited our unit. All patients fulfilled the European Community criteria for SS and underwent a complete history, physical examination, as well as biochemical and immunological evaluation for liver disease. Serum from all patients was tested for antibodies to HCV by third generation enzyme linked immunoassay and positivity was confirmed by polymerase chain reaction. RESULTS: Antibodies to HCV were present in 13 (14%) patients with 'primary' SS. When compared with patients without HCV infection, patients with HCV infection presented a higher prevalence of hepatic involvement, (100% v 8%, p < 0.05). Transcutaneous liver biopsy was performed in five patients with HCV infection, and specimens obtained showed in all cases a chronic active hepatitis with varying degrees of portal inflammation. CONCLUSION: HCV infection is frequent in patients with "primary' SS and liver involvement is presented in all these patients. The possible pathogenic role of HCV infection in these patients is still unclear.

Adult↗
PubMed1995

Results of out-patient cataract surgery in patients who live far from the surgeon.

We have performed this prospective study to address the question of whether there is an association between the outcome following cataract surgery and the distance from the patient's home to the place of surgery. Three hundred and forty consecutive out-patient extracapsular cataract extractions were evaluated. According to the distance, the cases were grouped into two categories, 183 cases in the nearest group (Group 1) and 157 cases in the farthest group (Group 2). A best corrected visual acuity of 0.5 or better was achieved in 90% of patients, 6 between the groups. No significant differences in rates for operative and postoperative complications were identified. This study does not show that the distance from the patient's home to the surgical site has had any adverse effect of surgical outcome or in rates of complications.

Aged↗
PubMed1995

Microphthalmos, facial capillary hemangioma and Dandy-Walker malformation.

We present a 6-month-old girl with the unusual combination of microphthalmos, facial capillary hemangioma and Dandy-Walker malformation. This is the fourth case with such an association reported in the literature. On the basis of the experience with our patient and with those previously reported, we stress the importance of performing brain-imaging studies on all infants with large facial hemangiomas, or if unusual ophthalmic findings are present.

Abnormalities, Multiple↗