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C Alvarado

Publications and source records attributed to C Alvarado.

At least 19 recordsLinked to original sources
PubMed2006

Nutritional evaluation of commercial dry dog foods by near infrared reflectance spectroscopy.

Near infrared reflectance spectroscopy (NIRS) was used to predict the nutritional value of dog foods sold in Chile. Fifty-nine dry foods for adult and growing dogs were collected, ground and scanned across the visible/NIR range and subsequently analysed for dry matter (DM), crude protein (CP), crude fibre (CF), total fat, linoleic acid, gross energy (GE), estimated metabolizable energy (ME) and several amino acids and minerals. Calibration equations were developed by modified partial least squares regression, and tested by cross-validation. Standard error of cross validation (SE(CV)) and coefficient of determination of cross validation (SE(CV)) were used to select best equations. Equations with good predicting accuracy were obtained for DM, CF, CP, GE and fat. Corresponding values for and SE(CV) were 0.96 and 1.7 g/kg, 0.91 and 3.1 g/kg, 0.99 and 5.0 g/kg, 0.93 and 0.26 MJ/kg, 0.89 and 12.4 g/kg. Several amino acids were also well predicted, such as arginine, leucine, isoleucine, phenylalanine-tyrosine (combined), threonine and valine, with values for and SE(CV) (g/kg) of 0.89 and 0.9, 0.94 and 1.3, 0.91 and 0.5, 0.95 and 0.9, 0.91 and 0.5, 0.93 and 0.5. Intermediate values, appropriate for ranking purposes, were obtained for ME, histidine, lysine and methionine-cysteine. Tryptophan, minerals or linoleic acid were not acceptably predicted, irrespective of the mathematical treatment applied. It is concluded that NIR can be successfully used to predict important nutritional characteristics of commercial dog foods.

Amino Acids↗
PubMed2005

Anti-Listeria monocytogenes bacteriocin-like inhibitory substances from Enterococcus faecium UQ31 isolated from artisan Mexican-style cheese.

Artisan fresh Mexican-style cheeses are commonly made from raw milk that provides not only rich flavors, but also a diversity of associated lactic acid bacteria (LAB) strains. Enterococcus faecium UQ31 was isolated from panela cheese and produced bacteriocin-like inhibitory substances (BLIS) with a strong anti-Listeria activity. A modified pH-mediated adsorption-desorption purification process resulted in (after SDS-PAGE) two bands showing antimicrobial activities, where most of the activity corresponded to the band with an estimated molecular weight of 7.5 kDa. The BLIS produced by E. faecium UQ31 were heat resistant, stable at ambient storage conditions, and active in the pH range 5--9. The BLIS antimicrobial activities were detected during logarithmic growth phase and remained constant until the end of incubation time (19 h). These BLIS showed a wide anti-Listeria monocytogenes spectra. The E. faecium UQ31 strain or their BLIS represent a promising potential as antimicrobial food preservatives.

Animals↗
PubMed2004

Changes with age in peritoneal macrophage functions. Implication of leukocytes in the oxidative stress of senescence.

The age-related deterioration of the immune cells contributes to the increased morbidity and mortality of the aged populations. Since ageing is the result of oxidative stress and macrophages are an important source of oxidation, which is produced in order to carry out many of their functions, the changes with age of several macrophage functions as well as of oxidative stress parameters (oxidants, inflammatory mediators and antioxidants) of peritoneal leukocytes have been investigated using young (4 months), adult (7 months), mature (12 months) and old (20 months) female ICR (CD-1) mice. With age the macrophage functions suffer deterioration. Thus, chemotaxis, phagocytosis and intracellular superoxide anion production decrease in old animals. Moreover, the levels of antioxidant defenses, such as superoxide dismutase activity, decrease with ageing. However, the adherence capacity and the release of oxidant and inflammatory mediators, such as extracellular superoxide anion, TNF-alpha and PGE2, as well as oxidized glutathione/ reduced glutathione ratio, increase with age. These results show that these cells suffer oxidative stress with ageing, which results in an increase of the oxidative damage to nuclear DNA. These changes in peritoneal immune cells could contribute to the chronic oxidative stress state linked to senescence.

Animals↗
PubMed2000

Reconciliation of FDA and societal guidelines for endoscope reprocessing.

Chemical sterilants are used to high-level disinfect semicritical medical devices such as flexible endoscopes. For the chemosterilant to obtain a high level disinfection claim, The Food and Drug Administration requires demonstration of a 6-log reduction of myobacterial inoculum under worst case conditions (2% horse serum added to test sterilant). This testing requirement has led to label product claims of 45 minutes immersion times at 25 degrees C. Review of the scientific data suggests that at least an 8-log reduction in contamination with thorough instrument cleaning, followed by chemical disinfection for 20 minutes immersion at 20 degrees C will achieve high-level disinfection.

Disinfection↗
PubMed1999

Pleuropulmonary blastoma and ovarian teratoma.

We report a patient with pleuropulmonary blastoma who had a benign teratoma as a second primary tumor. The radiology, clinical course, and the biological importance of this rare neoplasm are discussed.

Adolescent↗
PubMed1998

Spinobulbar muscular atrophy: polyglutamine-expanded androgen receptor is proteolytically resistant in vitro and processed abnormally in transfected cells.

The neuronotoxicity of genes with expanded CAG repeats is most likely mediated by their respective polyglutamine (Gln)-expanded gene products. Gln- expanded portions of these products may be sufficient, or necessary, for pathogenesis. We tested whether a Gln-expanded human androgen receptor (AR) is structurally altered, so that it allows for the proteolytic generation of a potentially pathogenic portion that may be resistant to further degradation. We found, in vitro , that a Gln-expanded AR is more proteolytically resistant than normal, and that it yields a distinct set of Gln-expanded fragments even after extended proteolysis in the presence of 2 M urea. Furthermore, COS cells transfected with CAG-expanded AR cDNA generate an aberrant, nuclear-associated 75 kDa derivative containing the Gln-expanded tract. They are also twice as likely to die by 24 h apoptotically than those transfected with normal AR cDNA. Our data support the notion that an unconventional derivative of the Gln- expanded AR is a component of the proximate motor neuronopathic agent in spinobulbar muscular atrophy. They also focus attention on two ways in which neuronotoxic derivatives may originate from various Gln-expanded proteins: (i) generation of an unusual derivative that is pathogenic de novo ; and (ii) the toxic accumulation of a normal derivative because of an inability to dispose of it.

Animals↗
PubMed1998

Prognostic significance of age, MYCN oncogene amplification, tumor cell ploidy, and histology in 110 infants with stage D(S) neuroblastoma: the pediatric oncology group experience--a pediatric oncology group study.

PURPOSE: Although a high rate of spontaneous regression is observed in infants with stage D(S) neuroblastoma (NB), survival is not uniform. To determine the prognostic relevance of age at diagnosis, therapy, and tumor biology in infants with stage D(S) NB, we reviewed the Pediatric Oncology Group (POG) experience. PATIENTS AND METHODS: A review of patients diagnosed with stage D(S) NB registered on POG protocols was performed. Survival according to age at diagnosis, treatment, and tumor biology was determined. RESULTS: Between 1987 and 1996, 110 infants with stage D(S) NB had an estimated 3-year survival rate of 85% +/- 4%; survival rate was 71% +/- 8% for infants 2 months of age or younger, and 68% +/- 12%, 44% +/- 33%, and 33% +/- 19% for patients with diploid, MYCN-amplified, and unfavorable histology tumors, respectively. Survival rates were similar for patients who received adjuvant chemotherapy versus those who did not (82% +/- 5% v 93% +/- 6%, respectively; P = .187). Furthermore, there was no statistical difference in survival rate for patients who underwent complete resection of their primary tumor compared with those who underwent partial resection or biopsy only (90% +/- 5% v 78% +/- 7%, respectively; P = .083). CONCLUSION: Our review confirmed that the survival of infants with stage D(S) NB is excellent. However, subsets of patients with poor prognosis can be identified by young age and unfavorable biologic factors. More effective therapy is needed for the group of stage D(S) infants who show unfavorable clinical and biologic features.

Age Factors↗
PubMed1997

Autoantibody production in healthy elderly people is not promoted by interleukin-10 although this cytokine is expressed in them by a peculiar CD8+CD3+ large granular cell subpopulation.

Healthy elderly people tend to have autoantibodies in their sera. These antibodies, not being associated with any clinical manifestation, have been considered as natural autoantibodies. In systemic lupus erythematosus, as well as in rheumatoid arthritis, the presence of autoantibodies characteristic of these disease (anti-dsDNA and rheumatoid factor, respectively) depends on the endogeneous production of IL-10. The same could hold true for autoantibodies found in healthy elderly individuals. In the present work, the authors analysed whether an increased production of IL-10 contributed to the production of autoantibodies in elderly people. The authors found that there is neither increased in vivo gene expression nor augmented production of IL-10 by peripheral blood mononuclear cells from elderly women even if they do produce autoantibodies. The authors further sought to determine if the production of autoantibodies is inhibited in vitro by adding an anti-IL-10 MoAb to cell cultures and found that it is not. Despite these negative findings of a role for IL-10 in the production of autoantibodies in elderly people, the authors investigated which cells produce IL-10. In so doing they found that intracellular IL-10 expression occurred exclusively in monocytes in young female controls, but in elderly females it involved also CD8+CD3+ large granular cells. These results indicate that autoantibody production in healthy aged individuals is IL-10 independent.

Adult↗
PubMed1997

Protein degradation in red cells exposed to 2,2'-azo-bis(2-amidinopropane) derived radicals.

Extensive proteolysis is observed when red blood cells are exposed to free radicals produced in the thermolysis of 2,2'-azo-bis(2-amidinopropane). It is evaluated that nearly one amino terminal group is produced by each free radical introduced into the system. These groups are considered to arise mainly from band 3 fragmentation due to the action of red cell proteinases. Protein fragmentation takes place prior to significant hemolysis or lipid peroxidation, as evaluated by thiobarbituric acid-reactive substances measurements.

Amidines↗
PubMed1997

Elevated Th1 cytokine mRNA in skin biopsies and peripheral circulation in patients with erythema nodosum.

It is generally believed that erythema nodosum is the result of an immunologic attack centered within the subcutaneous fat. This belief, however, is based on indirect evidence. The aim of this study was to analyze whether erythema nodosum could represent an example of a polarized Th1 or Th2 immune response. We have studied herein, by semiquantitative coupled reverse transcription-polymerase chain reaction the Th1 (IL-2, IFN-gamma) and Th2 (IL-4, IL-10) cytokine gene expression in skin biopsies and peripheral blood from eleven patients with erythema nodosum. As controls, we studied skin and peripheral blood from nine healthy subjects. We found expression of Th1 cytokines in most erythema nodosum skin lesions as well as in their peripheral blood. Both Th1 and Th2 cytokine gene expressions were scarcely or not detected in the skin and peripheral blood of control subjects. These results directly demonstrate that a polarized Th1 immune response occurs in the skin lesions of erythema nodosum patients regardless of the wide variety of provoking agents.

Adolescent↗
PubMed1995

Characterization of normal and point-mutated human androgen receptors expressed in the baculovirus system.

The baculovirus system is able to generate large amounts of a protein, permitting detailed analysis of structure-function relations. We have used this system to overexpress and characterize normal human androgen receptors (hAR) and mutant hARs from humans with complete or partial androgen insensitivity. Maximum specific binding of [3H]mibolerone (MB) in recombinant baculovirus-infected Spodoptera frugiperda (Sf9) cells varied from 15 to 40 pmol/mg protein, about 1000-fold higher than in genital skin fibroblasts, and peaked 48-72 h after infection. In contrast, Coomassie blue staining and Western blotting revealed maximum accumulation of 100-120 kDa hAR proteins 96 h post-infection. Normal and mutant hARs were specifically photo-affinity-labeled with [3H]methyltrienolone (MT), and had normal steroid-binding selectivity: the order of competition was androgen > estrogen > progestin > glucocorticoid. Normal hAR was phosphorylated in Sf9 cells, reacted with antibodies against phosphoserine and phosphothreonine after purification using testosterone-biotin, and transactivated a transfected androgen response element-luciferase reporter in infected Sf9 cells. Two mutant hARs had increased rates of dissociation from MB and MT that were in accord with the associated degree of clinical androgen insensitivity: complete, Pro903Ser > partial, Leu820Val; the third, Ile663Asn, was not abnormal. Our data extend the characterization of normal hAR produced by baculovirus-infected Sf9 cells, and demonstrate, for the first time, that point-mutated hARs so produced can display distinctive biochemical phenotypes.

Amino Acid Sequence↗
PubMed1994

Effect of CD28 antibody on T cells from patients with systemic lupus erythematosus.

CD28 is a 44-kDa glycoprotein that contributes to T cell activation and proliferation. To elucidate the functional role of CD28 in T cell proliferation and IL-2 production in SLE, we studied its effects in cells from untreated patients with active (n = 10) or inactive disease (n = 10) as compared with normal subjects. Mean percentages of CD4+ CD28+ and CD8+ CD28+ T cells were decreased in SLE patients (P < 0.01). SLE patients had significantly decreased absolute CD8+ CD28+ T cells. To investigate whether CD28 antibody affects T cell proliferation, we stimulated peripheral blood T cells from SLE patients and normal controls with anti-CD28, anti-CD3 and/or Interleukin-2 (IL-2) during 3 days of culture. We found that T cells from SLE patients had significantly higher responses to CD28 than did cells from normal controls. This effect was higher in cells from patients with active disease than in those with inactive disease. Conversely, IL-2 had no significant effect on the proliferative response of SLE T cells. However, when it was used for co-stimulating with anti-CD28, there was an increase in the secretion of IL-2 which was greater in the cells of patients with active disease. Thus, on average, there was an 81% increase in the production of IL-2 in T cells from patients with active SLE, 48% in those from patients with inactive disease and 40% in T cells from healthy controls, as compared with the production in response to stimulus by anti-CD3 or with anti-CD3 and anti-CD28. Lymphocytes from patients with active disease showed increased gene expression of CD28 when compared with normal subjects. These data suggest that CD28 might play a central role in the defective immune response observed in SLE patients.

Adult↗
PubMed1994

Complete androgen insensitivity due to mutations in the probable alpha-helical segments of the DNA-binding domain in the human androgen receptor.

We describe different single-amino acid aberrations in the DNA-binding domain (DBD) of the human androgen receptor (hAR) in three families with complete androgen insensitivity. No additional alteration was found in the translated portion of each mutant gene. In one family, an in-frame 3 nt deletion removes codon 581-(or 582) and, thereby, one of two phenylalanines that invariably occupy adjacent positions in the N-terminal alpha-helical region of the DBD in the steroid/thyroid/vitamin D receptor superfamily. In the second, an in-frame 3 nt loss deletes Arg614, an invariant residue in the C-terminal alpha-helix of the DBD. In the third, a G-->A transition causes Arg614His. Following transient transfection of COS cells with each mutant AR plasmid, there is a normal concentration of specific androgen-binding activity that has a reduced ability to bind two types of androgen response element (ARE), and to transregulate an androgen-responsive human growth hormone reporter gene. In genital skin fibroblasts with delta Phe581 or Arg614His, androgen-binding, AR protein and AR mRNA are markedly reduced; in gonadal fibroblasts with delta Arg614, AR mRNA may be reduced. Our data substantiate the primary contributions of Phe581 and Arg614 to normal hAR-ARE binding, and expose important secondary effects of the mutations affecting each residue.

Amino Acid Sequence↗
PubMed1992

Androgen resistance due to mutation of the androgen receptor.

The androgen receptor (AR) is a 'one-stop' signal transduction system that is the core of the intracellular androgen-response apparatus. It is an androgen-regulated, DNA-binding protein that regulates the expression of certain target genes, primarily at the transcriptional level. Mutations at the X-linked AR locus cause deficient or defective AR activity and, thereby, an extraordinarily wide spectrum of clinical androgen resistance. At one extreme, the affected 46,XY person is an infertile phenotypic female; at the other, he is a phenotypic male who may even be fertile, yet have gynecomastia or other focal signs of postpubertal subvirilization. We have identified 32 proven or putatively pathogenic alterations in the AR gene of 38 androgen-resistant families. This permits heterozygote detection and prenatal diagnosis whenever relevant. Most of the mutations affect the AR's androgen-binding domain, partly because our search has been targetted on those whose genital skin fibroblasts have impaired androgen-binding activities. The AR is a prototypic member of a subfamily that includes the receptors for progesterone, glucocorticoid, and mineralocorticoid. Observations that correlate AR genotype with clinical and receptor phenotypes of androgen resistance will help to generate a fine structure-function map of the AR and its close relatives. Constitutional variation in androgen sensitivity, that may be restricted to an organ (or organ system), could contribute to the pathogenesis of certain diseases whose sex ratio departs significantly from one.

Amino Acid Sequence↗
PubMed1992

The kallikrein-kinin system in early state of diabetes.

The kallikrein-kinin system was studied in 9 normals, healthy subjects (6 men, 3 women, age range 1 to 14 years) and 15 diabetic patients (9 men, 6 women age range 2 to 14 years) with an evolution of the disease between 1 to 14 years. Diabetic patients with low microalbuminuria (6.62 +/- 0.97 mg/24 h) show increased total and pre-kallikrein respect to control (3 and 2 fold respectively). On the other hand patients with high microalbuminuria (44.7 +/- 13.2 mg/24 h) show a total and pre-kallikrein of more than 4 and 8 fold increased respectively, compare with the control. According with these results we can concluded: 1) The total kallikrein and pre-kallikrein is increased in the diabetic state. 2) When microalbuminuria is high, the total and pre-kallikrein correlates with those increasing. 3) These changes could modified the renal hemodynamic in diabetes.

Adolescent↗
PubMed1991

The t(1;22) (p13;q13) is nonrandom and restricted to infants with acute megakaryoblastic leukemia: a Pediatric Oncology Group Study.

We report the nonrandom occurrence and frequency of the t(1;22)(p13;q13) in acute myeloid leukemia (AML) and its close association with the French-American-British M7 subtype of AML in infants (less than 1 year). This chromosomal abnormality occurred in 6 of 252 (2.4%) children and adolescents with AML (6 of 28 infants, 22%; 6 of 18 M7 AML cases overall, 33%; and 6 of 6 M7 cases in infants). Infants with AML of M7 subtype and the t(1;22) often presented with prominent abdominal masses. Two of these infants were not treated and died early. Three of four treated infants entered complete remission with therapy for AML; the remaining infant died of hemorrhage on day 8. Of the three infants who entered remission, only one remains alive and disease free at 5+ months. The other two infants relapsed in the bone marrow at 5 and 2 months from the start of therapy, respectively. We conclude that M7 AML with the t(1;22) usually presents in infants with extensive infiltration of abdominal organs by leukemic cells and may confer a poor prognosis despite intensive AML-directed treatment. Identification of this nonrandom translocation exclusively in infants with acute megakaryoblastic leukemia (AMkL) implies that it may serve as an additional diagnostic marker for this disease and links it to the pathogenesis of AMkL in infants.

Antigens, CD↗
PubMed1990

Toxicity of high-dose cytosine arabinoside in the treatment of advanced childhood tumors resistant to conventional therapy. A Pediatric Oncology Group study.

Experience with high-dose cytosine arabinoside (HDAC) in pediatric solid tumors is limited. Sixteen children with solid tumors resistant to conventional therapies were registered in a pilot Pediatric Oncology Group (POG) study that required the administration of HDAC at 3 g/m2 every 12 hours for four doses. There were four cases of rhabdomyosarcoma, two cases of fibrosarcoma, four cases of neuroblastoma, and one case each of germ cell tumor, Wilm's tumor, retinoblastoma, hepatocellular carcinoma, Ewing's sarcoma, and Burkitt's lymphoma. All eligible patients had advanced diseases and had previously received extensive chemotherapy. Thirteen patients received one course of HDAC and three patients received two courses of HDAC. Due to prior treatments, patients had less than normal marrow reserves. Short-term toxicity included nausea, vomiting, suppression of hemopoiesis, drug fever, and increased blood urea nitrogen (BUN), creatinine, and liver enzymes. All evaluable patients recovered from their toxicities. There were no drug-related deaths. None of the patients had neurologic problems, including the only patient with prior irradiation to the skull. With the above schedule, HDAC appears to have manageable toxicity.

Child↗