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Biomedical subjects

E Castaño

Publications and source records attributed to E Castaño.

31 records · Page 2Linked to original sources
PubMed1998

[Importance of Mycoplasma pneumoniae and Chlamydia pneumoniae in children with community-acquired pneumonia].

OBJECTIVES: To determine the importance of Mycoplasma pneumoniae and Chlamydia pneumoniae in community-acquired pneumonia (CAP) of children from different latitudes and to compare clinical outcome using azithromycin (AZM) versus either amoxicillin-clavulanate (A-C) or erythromycin estolate (EE). METHODS: Ambulatory patients with CAP were identified at either the Children's Medical Center of Dallas, Texas or the Hospital del Niño of Panama City, Panama. Children 6 months to 15 years of age were enrolled and randomized to receive either AZM for 5 days or a 10 day course of either A-C or EE, for those younger or older than 5 years of age, respectively. Mycoplasma pneumoniae and C. pneumoniae were identified by measuring acute and convalescent serum antibody titers and by performing nasopharyngeal (NP) and oropharyngeal (OP) swabs for culture and polymerase chain reaction (PCR) testing. RESULTS: Overall 335 patients (168 in Dallas and 167 in Panama) were evaluated from February 1996 through December 1997. Acute M. pneumoniae infection was detected in 12 (7%) patients each in Dallas and Panama. Acute C. pneumoniae infection was observed in 10 (6%) children at each site. Infection caused by these "atypical" microorganisms occurred more frequently in children older than 5 years of age (23% vs 9%, P = 0.001, RR 2.5, 95% CI 1.4-4.3). No distinctive pattern of clinical or radiologic abnormalities was seen in relation to etiology. Clinical cure was achieved in 43 of 44 children infected by these bacteria regardless of treatment assignment. CONCLUSION: Mycoplasma pneumoniae and C. pneumoniae are common etiologic agents of CAP in older children from different latitudes. Children with CAP present with similar clinical and radiologic findings to those caused by other etiologic agents. Outcome was excellent for the three treatment regimens studied.

Adolescent↗
PubMed1998

[Primary ureteral amyloidosis].

OBJECTIVE: Two additional cases of primary ureteral amyloidosis are described. The current literature and clinical classification of the disease are reviewed. METHODS: Over a period of 18 months, we observed two cases of organic ureteral stenosis whose etiology was difficult to determine. The first case warranted a nephroureterectomy due to the condition of the compromised urinary tract. Analysis of the surgical specimen showed histological evidence of ureteral amyloidosis. In the second case, the previous experience allowed a preoperative diagnosis to be made, an exceptional situation that permitted conservative surgery. Characterization of the amyloid proteins was done in both cases with immunochemical study by Western Blot. RESULTS: Two patients with primary ureteral amyloidosis were surgically treated. The first case underwent complete excision of the urinary tract. The second case, who had a single kidney, was treated by conservative surgery. In both cases we identified a fragment of the lambda light chain of immunoglobulin by Western Blot characterization as previously reported in localized amyloidosis. CONCLUSIONS: Although ureteral amyloidosis is an infrequent disease, it should be seriously considered in the differential diagnosis of organic ureteral stenosis in order to avoid unnecessary excision. To our knowledge, these are the first cases of ureteral amyloidosis with immunochemical characterization of the amyloid protein.

Aged↗
PubMed1997

Phosphorylation of serine-167 on the human oestrogen receptor is important for oestrogen response element binding and transcriptional activation.

We have studied the role of phosphorylation of the human oestrogen receptor (hOR; otherwise known as hER) at serine-167, which has been identified previously as the major oestrogen-induced phosphorylation site. We have tested transactivation by the hOR in yeast and cell-free transcription assays, and shown that mutation of serine-167 results in a 70% decrease in hOR-dependent transcription. Furthermore we explored the functional significance of phosphorylation at this site by hormone binding and DNA binding. DNA binding affinity was 10-fold lower when serine-167 was changed to alanine in the hOR. Cell-free transcription experiments showed that casein kinase II is the enzyme responsible for oestradiol-dependent phosphorylation of the hOR at serine-167. This suggests that a conformational change of the hOR must occur upon hormone binding that exposes serine-167 to casein kinase II, resulting in transactivation of oestrogen-responsive genes.

Casein Kinase II↗
PubMed1997

Na+,K(+)-ATPase expression in maleic-acid-induced Fanconi syndrome in rats.

Na+,K(+)-ATPase activity and its alpha 1 subunit protein and mRNA in kidney cortex were monitored in rats developing Fanconi syndrome after the administration of maleate. Na+,K(+)-ATPase activity was significantly lower than in saline-injected controls, although this was partially mediated by a general, non-specific decrease in the cortex protein content. 2. The low activity of the sodium pump correlated with low abundance of alpha 1 subunit mRNA and protein levels. Hsp60 protein levels were also decreased in kidney cortex from maleate-treated rats. 3. Kidney cortex brush-border membrane vesicles from maleate-treated rats showed a marked decrease in Na(+)-dependent alanine and glucose transport, which was not dependent on the Na(+)-transmembrane gradient itself, a finding which is consistent with a more stable effect at the plasma membrane level. 4. The effect of maleate may be partially non-specific and involve a great variety of proteins, but seems to be restricted to selected tissues because alpha 1 subunit Na+,K(+)-ATPase and hsp60 protein amounts were not significantly modified in livers from rats developing Fanconi syndrome. 5. These results show that maleate administration induces a low activity of selected concentrative transport systems and a decrease in Na+,K(+)-ATPase activity and expression. The combination of both effects may explain the increased excretion of most organic solutes present in rats developing Fanconi syndrome.

Alanine↗
PubMed1997

Verrucous carcinoma in association with hypertrophic lichen planus.

Neoplastic transformation of lichen planus is a rare event. However, squamous cell carcinoma may develop in 0.3%-3% of patients with the oral form of the disease. On the other hand, less than 30 cases arising in cutaneous lichen planus have been reported, and only four cases of verrucous carcinoma in association with either form, one with an oral lesion and three with cutaneous lesions (one hypertrophic and one ulcerative). This report describes the unusual progression of a hypertrophic lichen planus plaque of the right leg to a verrucous carcinoma in a 40-year-old woman.

Adult↗
PubMed1997

Glomangiosarcoma of the lower limb: a case report with a literature review.

Glomangiosarcoma (GS) is a very unusual but morphologically distinctive tumor of soft tissue. We report a case of GS which occurred in the subcutaneous tissue of a 56-year-old man. Microscopically, a typical glomus tumor surrounded a central area of sarcoma. Immunohistochemical stains were performed, and there was a strong positive reaction for vimentin, muscle-specific actin and smooth muscle actin. We also review the clinicopathologic findings of the 9 GS that have previously been reported.

Adipose Tissue↗
PubMed1997

Molecular and kinetic basis for the mixed agonist/antagonist activity of estriol.

Estriol acts as a weak estrogen when administered in a single dose into immature or ovariectomized laboratory animals, but produces full estrogenic responses upon chronic administration. However, when estriol is injected together with estradiol it acts as an antiestrogen. We studied the dual agonist/antagonist properties of estriol, using recombinant human estrogen receptor (hER) in ligand-binding assay, cell-free transcription assay, electrophoretic mobility shift assay with cVitII estrogen response element (ERE), and ERE-Sepharose chromatography. We show that the weak estrogenic activity of estriol results from impaired hER-ERE interaction. The antiestrogenic activity of estriol was demonstrated in a cell-free transcription assay where it reduced estradiol-dependent transcription in a dose-dependent manner. Estriol interfered with estradiol-induced positive cooperative binding and receptor dimerization, and binding of hER complexes to ERE. These effects of estriol were maximal at a 10-fold molar excess over estradiol; under these conditions estradiol-dependent transcription was decreased by 85%, although [3H]estradiol binding was reduced by only 50%. We propose that when hER, estradiol, and estriol are coequilibrated, several receptor species are formed: unliganded hER monomers and dimers; estradiol-hER monomers and dimers, estriol-hER monomers and dimers; and presumably mixed estradiol-estriol dimers. Since estrogen-hER complexes bind cooperatively to ERE sequences, the concentrations of transcriptionally active complexes (estriol- and estradiol-hER dimers) are reduced to low levels that fail to bind cooperatively with ERE and initiate transcription. We discuss our results in relation to the massive estriol production during pregnancy and to the "Estriol Hypothesis" on the protective role for estriol in opposing carcinogenic effects of estradiol.

Cell-Free System↗
PubMed1997

Inhibition of DNA synthesis by aspirin in Swiss 3T3 fibroblasts.

In Swiss 3T3 fibroblasts, aspirin inhibited proliferation induced by the complete mitogenic factors platelet-derived growth factor (PDGF) and bombesin. Aspirin decreased the maximum mitogenic effect of bombesin without modifying the concentration necessary to obtain half maximal DNA synthesis stimulation. In contrast, aspirin only decreased mitogenesis at subsaturating PDGF concentrations. The effect of aspirin was found to be concentration dependent. The half-maximal effect occurred at approximately 150 microM. The maximal inhibition was obtained when aspirin was added during the first hour after growth factor addition. At this time, both PDGF and bombesin induced prostaglandin E2 synthesis. PDGF induced much higher levels of prostaglandin E2 than bombesin. The inhibitory effects of aspirin on PDGF or bombesin-stimulated DNA synthesis were counteracted by 280 nM prostaglandin E2. Aspirin effects were overcome by agents that increase cellular cyclic adenosine monophosphate levels but not by activation of protein kinase C. The significance of the antiproliferative action of aspirin might be associated with epidemiological data that show a reduced incidence of colorectal and other cancers after aspirin treatment.

3T3 Cells↗
PubMed1995

Intrapartum prophylaxis with ceftriaxone decreases rates of bacterial colonization and early-onset infection in newborns.

Because of high rates of neonatal gram-negative sepsis in many Latin American countries, we prospectively enrolled 784 high-risk pregnant women in a study designed to evaluate the effect of a single 1-g dose of ceftriaxone (n = 390) vs. that of no antibiotic prophylaxis (n = 394) on oral, rectal, and umbilical colonization and fatality rates among newborn infants. The mean ceftriaxone concentration in cord blood samples was 26 microgram/mL (range, 9-40 microgram/mL). Compared with infants of untreated mothers, children born to women who were given ceftriaxone were colonized at a lesser rate by gram-negative bacilli (54% vs. 35%; P < .001) and by group B streptococci (54% vs. 21%; P = .03) and endured significantly fewer sepsis-like illnesses in the first 5 days of life (8.1% vs. 3.1%; P = .004). There was also a tendency for them to have fewer episodes of culture-proven early-onset sepsis (2.8% vs. 0.5%; P = .06). Sepsis-related case-fatality rates (0.8% and 0.3%, respectively) were not significantly different. Although intrapartum administration of a single dose of ceftriaxone to high-risk mothers could be a safe and potentially useful strategy for reducing early-onset neonatal infections, additional information is required before this approach can be recommended for routine prophylaxis.

Bacterial Infections↗
PubMed1995

Prospective randomized comparison of cefepime and cefotaxime for treatment of bacterial meningitis in infants and children.

Ninety infants and children were prospectively randomized to receive cefepime (n = 43) or cefotaxime (n = 47) for therapy of bacterial meningitis. The two treatment groups were comparable in terms of age, duration of illness before enrollment, history of seizures, clinical status on admission, and etiology. Six (7%) patients died--two treated with cefepime and four treated with cefotaxime. Clinical response, cerebrospinal fluid sterilization, development of complications, antibiotic toxicity, and hospital stay were similar for the two treatment regimens. Concentrations of cefepime in cerebrospinal fluid varied from 55 to 95 times greater than the maximal MIC required by the causative pathogens. Audiologic and/or neurologic sequelae were found in 16% of the cefepime-treated patients and 15% of the cefotaxime-treated patients examined 2 to 6 months after discharge. We conclude that cefepime is safe and therapeutically equivalent to cefotaxime for management of bacterial meningitis in infants and children.

Adolescent↗
PubMed1988

Differences between vascular and plaque core amyloid in Alzheimer's disease.

The predominant protein of cerebrovascular and plaque core amyloid in Alzheimer's disease, Down's syndrome, hereditary hemorrhage with amyloidosis--Dutch type, sporadic cerebral amyloid angiopathy, and age-related amyloidosis is a unique polypeptide, called beta protein. The length of the plaque amyloid protein was reported to be 42-43 residues, but the complete length of the cerebral vascular amyloid is not known. To clarify this issue, amyloid fibrils from the leptomeninges of an Alzheimer's disease patient were isolated and the primary structure determined. The complete sequence of cerebrovascular beta-amyloid protein, although homologous to the plaque core amyloid protein previously reported, has 39 residues instead of 42. Amino terminal heterogeneity is present but minimal, and it is three residues shorter at the carboxy terminus. These differences are similar to those found in two cases of hereditary hemorrhage with amyloidosis--Dutch type. The differences between vascular and plaque beta-amyloid may reflect diverse processing of the beta protein precursor in the vessel wall and brain parenchyma due to tissue-specific endopeptidases.

Alzheimer Disease↗
PubMed1988

Isolation and characterization of amyloid P component from Alzheimer's disease and other types of cerebral amyloidosis.

The presence of amyloid P-component (AP) within cerebral amyloid deposits was investigated by means of biochemical and immunocytochemical methods. Immunoperoxidase on formalin-fixed, paraffin-embedded tissue sections from Alzheimer's Disease, Down's Syndrome, asymptomatic age-related cerebral amyloidosis, sporadic cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis-Icelandic type, and hereditary cerebral hemorrhage with amyloidosis-Dutch type revealed the presence of AP in the affected vessel walls in all cases, and in parenchymal deposits resembling neuritic plaques of Alzheimer's disease, sporadic cerebral amyloid angiopathy, and hereditary cerebral hemorrhage with amyloidosis-Dutch type. A short digestion of tissue sections with pepsin was required for immunodetection of AP in these latter structures. After extraction of leptomeningeal amyloid fibrils, AP was characterized by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis, Western blot, gel chromatography, and partial amino acid sequencing. Our results indicate that: (a) AP from cerebral amyloidosis has similar biochemical properties and homologous amino terminal sequence to AP from systemic amyloidosis; (b) AP is associated to a variety of brain amyloid deposits regardless of their chemical nature. The presence of AP, a serum protein, within the brain parenchyma points to an impairment of the blood-brain barrier in these diseases.

Alzheimer Disease↗