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C Coronel

Publications and source records attributed to C Coronel.

7 recordsLinked to original sources
PubMed2005

Thymic cyst in the neck.

A rare case of a thymic cyst in the neck containing both thymus and parathyroid tissue in a 7-year-old boy is presented. The clinical presentation, diagnostic evaluation, surgical management and histopathological features are described. The embryology of cervical thymic cysts and the differential diagnosis of cystic neck masses in children are briefly reviewed. The diagnosis is seldom made preoperatively. Surgical resection is the treatment of choice for definitive diagnosis, resolution of symptoms and cure.

Child↗
PubMed2002

[Low-weight syndrome associated with COPD in our setting].

UNLABELLED: The high prevalence of chronic obstructive pulmonary disease (COPD) has considerable economic and health-related impact. The consequences arise largely from limitations on a patient's activity and shortened life expectancy. Low body weight has recently been implicated as a factor affecting limitations. Although the reason is not clear, weight loss appears to affect many patients (from 25 to 35% in different series), at least in Europe and North America. However, the situation is thought to be different in the Mediterranean area. OBJECTIVE: To estimate the prevalence of the low weight syndrome in patients with COPD in our area. METHODS: COPD patient characteristics monitored by our laboratory over the last two years (2000 and 2001) were reviewed. RESULTS: The prevalence of a body mass index (BMI) less than 20 kg/m2 was only 6.6% among the 3,126 patients studied. That percentage fell to 3.1% with a cutoff of 18 kg/m2. The figure was even more striking if we consider that half the patients had severe disease (FEV1 < 50% of reference). BMI was directly related to FEV1/FC and CO transfer. CONCLUSIONS: These results suggest that COPD patients in our geographic area have characteristics that distinguish them from those previously described in other countries. Specifically, the prevalence of low weight syndrome in our area appears to be lower. However, larger studies should be performed to confirm this finding.

Aged↗
PubMed1991

Increased gene expression of Alzheimer disease beta-amyloid precursor protein in senescent cultured fibroblasts.

The pathological hallmark of Alzheimer disease is the accumulation of neurofibrillary tangles and neuritic plaques in the brains of patients. Plaque cores contain a 4- to 5-kDa amyloid beta-protein fragment which is also found in the cerebral blood vessels of affected individuals. Since amyloid deposition in the brain increases with age even in normal people, we sought to establish whether the disease state bears a direct relationship with normal aging processes. As a model for biological aging, the process of cellular senescence in vitro was used. mRNA levels of beta-amyloid precursor protein associated with Alzheimer disease were compared in human fibroblasts in culture at early passage and when the same fibroblasts were grown to senescence after more than 52 population doublings. A dramatic increase in mRNA was observed in senescent IMR-90 fibroblasts compared with early-passage cells. Hybridization of mRNA from senescent and early proliferating fibroblasts with oligonucleotide probes specific for the three alternatively spliced transcripts of the gene gave similar results, indicating an increase during senescence of all three forms. A similar, though more modest, increase in message levels was also observed in early-passage fibroblasts made quiescent by serum deprivation; with repletion of serum, however, the expression returned to previous low levels. ELISAs were performed on cell extracts from senescent, early proliferating, and quiescent fibroblasts, and quiescent fibroblasts repleted with serum for over 48 hr, using polyclonal antibodies to a synthetic peptide of the beta-amyloid precursor. The results confirmed that the differences in mRNA expression were partially reflected at the protein level. Regulated expression of beta-amyloid precursor protein may be an important determinant of growth and metabolic responses to serum and growth factors under physiological as well as pathological conditions.

Alzheimer Disease↗
PubMed1990

Processing of Alzheimer's disease-associated beta-amyloid precursor protein.

Studies were undertaken on the processing of Alzheimer's disease-associated beta-amyloid precursor protein in normal cultured human fibroblasts and a human neuroblastoma cell line. Major differences in processing between the secreted and intracellular forms of the precursor were found. The intracellular form appears to undergo amino-terminal processing yielding many smaller fragments, whereas the secreted form does not show any further proteolytic cleavage after its release from the cell surface. In pulse-chase experiments, antibodies to the A4 region immunoprecipitated bands of Mr = 92,000-128,000, which represent the intact precursor; several smaller intracellular fragments of Mr = 70,000-72,000, 55,000, 33,000 and 6,000 also immunoprecipitated with this antibody. The Mr = 6,000 band cleared from the cell very quickly and is postulated to be the A4-carrying remnant of the secreted protein. The data show that a fragment of Mr = 33,000, which includes the A4 region, is one stable processed end-product of the intracellular precursor protein. It is possible that different posttranslational modifications are the signals responsible for the differences in processing between the secreted and intracellular amyloid precursor protein.

Alzheimer Disease↗
PubMed1981

Properties of alpha-hydroxyacid dehydrogenase isozymes from Trypanosoma cruzi.

Whole cell extracts of culture epimastigotes of Trypanosoma cruzi (Tulahuén strain) have alpha-hydroxyacid dehydrogenase activity which catalyzes the NAD-linked reaction alpha-ketoacid in equilibrium with alpha-hydroxyacid, with a variety of substrates. Two molecular forms of the enzyme have been separated by means of gel electrophoresis. These isozymes were partially purified by DEAE-cellulose chromatography and ammonium sulfate precipitation. Molecular weights were estimated and some catalytic properties were determined with purified isozymes. The faster migrating fraction (isozyme I) has a molecular weight of 85 500 and showed significant activity against linear 3-5 carbon chain substrates. The lowest Km value was obtained for pyruvate. Isozyme II (MW 60 500) utilizes linear and branched chain substrates with 4-6 carbon atoms. Its highest activity and lowest Km value were recorded with alpha-keto-isocarproate as substrate.

Alcohol Oxidoreductases↗