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Biomedical subjects

A Díaz

Publications and source records attributed to A Díaz.

At least 55 records · Page 3Linked to original sources
PubMed2000

Collection, processing and cryopreservation of umbilical cord blood for unrelated transplantation.

Umbilical cord blood (UCB) transplantation is being used as an alternative source of hematopoietic stem cells for bone marrow reconstitution. Separation and processing of UCB samples in large numbers for storage in cord blood banks ideally needs to be partially automated. The aim of this study was to establish and standardize a method for unrelated cord blood banking as well as the biological characterization of the samples. Up to October 1999, a total of 938 UCB units (mean volume 84.6 +/- 23.6 ml, nucleated cell (NC) count 0.90 +/- 0.37 x 109, total CFU-GM 79 +/- 72 x 104, CD34+ cell count 2.46 +/- 2.72 x 106) had been collected. Twenty-three per cent of all UCB samples had a NC count below 0.4 x 109 and were discarded. The initial bacterial contamination rate was reduced to less than 5% as a result of extensive training in collection procedures. Using a modification of a triple bag system and adding a solution of 6% hydroxyethyl starch, the UCB was separated by two centrifugation steps into three components: buffy coat, red cell and plasma fractions. The overall recoveries for NC, CFU-GM and CD34+ cells were 87.4 +/- 8.5%, 88.8 +/- 6.6% and 90.3 +/- 12.4%, respectively, in a mean final volume of 27 +/- 4.2 ml.

Blood Banks↗
PubMed2000

Expression of the proteinase specialized in bone resorption, cathepsin K, in granulomatous inflammation.

BACKGROUND: The cysteine proteinase cathepsin K has aroused intense interest as the main effector in the digestion of extracellular matrix during bone resorption by osteoclasts. The enzyme is not a housekeeping lysosomal hydrolase, but is instead expressed with striking specificity in osteoclasts. In this work, we present evidence for the association of cathepsin K with the granulomatous reaction. Granulomas are inflammatory tissue reactions against persistent pathogens or foreign bodies. We came across cathepsin K while working on Echinococcus granulosus, a persistent tissue-dwelling, cyst-forming parasite that elicits a granulomatous response. MATERIALS AND METHODS: The walls of hydatid cysts from infected cattle were solubilized. Strong proteolytic activity was detected in the extracts. The proteinase responsible was purified by anion exchange and gel filtration. The purified protein was subjected to N-terminal sequencing, and its identity further confirmed by Western blotting, with a cathepsin K-specific antibody. The same antibody was used to localize the proteinase in paraffin-embedded sections of the parasite and the local host response. RESULTS: A proteinase was purified to near homogeneity from hydatid cyst extracts. The enzyme was unequivocally identified as host cathepsin K. Both the proenzyme and the mature enzyme forms were found. Cathepsin K was then immunolocalized both to the parasite cyst wall and to the epithelioid and giant multinucleated cells of the host granulomatous response. CONCLUSIONS: In the granulomatous response to the hydatid cyst, cathepsin K is expressed by epithelioid and giant multinucleated cells. We propose that, by analogy with bone resorption, cathepsin K is secreted by the host in an attempt to digest the persistent foreign body. Both processes, bone resorption and granulomatous reactions, therefore tackle persistent extracellular material (the bone matrix or the foreign body), and utilize specialized cells of the monocytic lineage (osteoclasts or epithelioid/giant cells) secreting cathepsin K as an effector.

Amino Acid Sequence↗
PubMed1999

Differential effects of biotin deficiency and replenishment on rat liver pyruvate and propionyl-CoA carboxylases and on their mRNAs.

Although the role of vitamins as prosthetic groups of enzymes is well known, their participation in the regulation of their genetic expression has been much less explored. We studied the effect of biotin on the genetic expression of rat liver mitochondrial carboxylases: pyruvate carboxylase (PC), propionyl-CoA carboxylase (PCC), and 3-methylcrotonyl-CoA carboxylase (MCC). Rats were made biotin-deficient and were sacrificed after 8 to 10 weeks, when deficiency manifestations began to appear. At this time, hepatic PCC activity was 20% of the control values or lower, and there was an abnormally high urinary excretion of 3-hydroxyisovaleric acid, a marker of biotin deficiency. Biotin was added to deficient primary cultured hepatocytes. It took at least 24 h after the addition of biotin for PCC to achieve control activity and biotinylation levels, whereas PC became active and fully biotinylated in the first hour. The enzyme's mass was assessed in liver homogenates from biotin-deficient rats and incubated with biotin to convert the apocarboxylases into holocarboylases, which were detected by streptavidin blots. The amount of PC was minimally affected by biotin deficiency, whereas that of the alpha subunits of PCC and of MCC decreased substantially in deficient livers, which likely explains the reactivation and rebiotinylation results. The expression of PC and alphaPCC was studied at the mRNA level by Northern blots and RT/PCR; no significant changes were observed in the deficient livers. These results suggest that biotin regulates the expression of the catabolic carboxylases (PCC and MCC), that this regulation occurs after the posttranscriptional level, and that pyruvate carboxylase, a key enzyme for gluconeogenesis, Krebs cycle anaplerosis, and fatty acid synthesis, is spared of this control.

Animals↗
PubMed1999

A randomized blinded clinical trial of two antivenoms, prepared by caprylic acid or ammonium sulphate fractionation of IgG, in Bothrops and Porthidium snake bites in Colombia: correlation between safety and biochemical characteristics of antivenoms.

A randomized blinded clinical trial was performed in 53 patients bitten by Bothrops sp. and Porthidium sp. in Antioquia and Chocó, Colombia, in order to compare the efficacy and safety of two antivenoms made of whole IgG obtained by either ammonium sulphate (monovalent anti-B. atrox) or caprylic acid (polyvalent) fractionation. Additionally, antivenoms were compared by electrophoretic and chromatographic analyses and anticomplementary activity in vitro. With a protocol of 2, 4 and 6 antivenom vials for the treatment of mild, moderate and severe envenomings, respectively, both antivenoms were equally efficient to neutralize the most relevant signs of envenoming and to clear serum venom levels in patients from the first hour and later on. Three patients with severe envenoming and initially treated with less than six vials on admission had persistent or recurrent venom antigenemia within 12-48 h. Monovalent antivenom fractionated by ammonium sulphate precipitation had higher amounts of protein aggregates and nonimmunoglobulin proteins than polyvalent antivenom fractionated by caprylic acid precipitation. Both antivenoms presented anticomplementary activity in vitro, being higher in the monovalent product. In agreement, monovalent antivenom induced a significantly higher incidence of early antivenom reactions (52%) than polyvalent antivenom (25%).

Adolescent↗
PubMed1999

Control of host complement activation by the Echinococcus granulosus hydatid cyst.

Cystic hydatid disease is caused by the multicellular parasite Echinococcus granulosus. The hydatid cyst, being a long-lived, large, antigenic structure lodged in the host's internal organs, could potentially elicit major inflammatory responses. However, in practice, the cyst causes only minimal local inflammation. The complement system is a major pathway to immune-mediated inflammation. Recent results have shown that the host-exposed structure of the cyst, the hydatid cyst wall (HCW), fails to trigger the complement system strongly. We have carried out a wide survey for the mechanisms making the cyst wall relatively complement-inert. The results of those studies are summarised in this work, with emphasis on the most recently identified of the complement inhibitory mechanisms. This is based on a non-protein heat-stable, parasite inhibitor of the activation of host complement factor B.

Animals↗
PubMed1999

Attempted suicide: repetition and survival--findings of a follow-up study.

OBJECTIVE: This was a prospective follow-up study of suicidal patients to assess the influence over time of different risk factors, whether on completed suicides or reattempts. Survival analysis makes it possible to weigh the influence of variables that increase or decrease a patient's life span or that make reattempts less likely. METHOD: A cohort of 150 patients admitted to a psychiatric department after a suicide attempt was followed up over 10 years. The study protocol used standardized criteria, and periodic controls were carried out in all patients. RESULTS: In total, 12% of patients completed suicide, 10% died from natural causes, 75% were still alive and 25% reattempted. In the survival analysis the risk for completed suicide or reattempting was highest during the first 2 years after the index attempt admission. Global Assessment of Functioning (GAF) was the factor that most increased survival time. The number of previous attempts decreased survival time and increased the risk of reattempts. CONCLUSION: Since suicidal risk varied over time, intensifying contact with patients during periods of psychopathological change or life events could prolong their survival.

Adolescent↗
PubMed1999

Adaptive strategies of edaphic arthropods.

For those arthropod species adapted for living below the soil surface, the soil is a refuge from the biotic and abiotic perturbations existing above ground. Convergent morphological, physiological, and behavioral adaptations of epedaphic, euedaphic, and hemiedaphic arthropods to selective aspects of subterranean existence are examined in light of overlapping ecological niches. The abiotic impact of the soil environment and its relationship to arthropod evolution, radiation, and ecology are discussed as well. Specific areas addressed include the invasion of land by marine arthropods, the impact of morphology on arthropod mobility, osmoregulatory/respiratory systems, and defensive strategies.

Journal Article↗
PubMed1999

Differential effects of respiratory syncytial virus and adenovirus on mononuclear cell cytokine responses.

Respiratory syncytial virus (RSV) and adenovirus (Advs) serotype 3 (Adv3) and 7h (Adv7h) are associated with mild to severe respiratory infection and are indistinguishable during the acute phases of the illnesses. However, outcome and long-term prognosis are different with both infections. RSV infection is associated with later development of asthma, and Adv, mainly Adv7h, with severe lung damage, bronchiectasis, and hyperlucent lung. We hypothesized that this difference could be partly due to different immune responses induced by these viruses. To test this hypothesis we quantified TCD4+, TCD8+, and BCD19+ expressing the interleukin-2 receptor-alpha chain (CD25) and interferon-gamma (IFN-gamma), interleukin (IL)-10, and IL-4 in the supernatant of peripheral blood mononuclear cells (PBMC) from school children infected in vitro with and without RSV, Adv7h, and Adv3 and after phytohemagglutinin (PHA) stimulation in the presence or absence of these viruses at a multiplicity of infection (MOI) of 1. PBMC from every child produced more IL-10 (p </= 0.05) when infected with RSV than with Advs and noninfected control, and Adv induced more (p </= 0.05) IFN-gamma than did RSV and control. The IL-10/IFN-gamma ratio was significantly higher (p </= 0.05) in RSV-infected and significantly lower (p </= 0.05) in Adv-infected PBMC, than in noninfected cells. PHA-stimulated BCD19+ RSV- infected cells expressed more (p </= 0.05) IL-2R than did Adv-infected cells. These results suggest that Advs induce a Th-1-type immune response that is not seen with RSV. These patterns persist despite intersubject variation in the absolute quantity of cytokine produced.

Adenovirus Infections, Human↗
PubMed1999

[Adrenal oncocytoma].

OBJECTIVE: To describe an additional case of adrenocortical oncocytoma that had been incidentally discovered. METHODS/RESULTS: A case of adrenocortical oncocytoma in a 30-year-old male is presented. Patient evaluation by US, CT and arteriography revealed a well-defined mass between the upper pole of the left kidney, spleen and stomach, that appeared to be of adrenal origin. Histopathological and ultrastructural studies revealed a benign adrenocortical oncocytoma with moderate cell atypia but with no signs of infiltration. CONCLUSION: Adrenocortical oncocytoma must be included in the differential diagnosis of solid adrenal tumors.

Adenoma, Oxyphilic↗
PubMed1999

Concordance between hip ultrasonography and hip arthrography in the assessment of developmental dysplasia of the hip.

Controversy exists regarding the possibility of predicting hip reducibility in the congenitally dislocated hip, with arthrography still regarded as the gold standard in this situation. This study aims at assessing the degree of concordance between ultrasonography and arthrography in the detection of anatomic elements obstructing hip reduction. Forty-nine hips were studied both by ultrasonography and arthrography. Three anatomic sources of obstruction to reduction were assessed in each hip: ligamentum teres hypertrophy, inverted labrum, and the presence of soft tissue in the acetabulum. For each variable, congruence between ultrasound and arthrography was measured by kappa analysis. Values > 0.40 expressed sufficient concordance, and they were detected with regard to inverted labrum and the presence of soft tissue in the acetabulum. The results of this study suggest that ultrasonography may be considered a reliable technique for the prediction of the main causes of obstruction in the congenitally dislocated hip, such as inverted labrum and soft tissue in the acetabulum.

Arthrography↗
PubMed1998

Dynamics of antigenemia and coproantigens during a human Fasciola hepatica outbreak.

In the present study the dynamics of antigenemia and coproantigens were studied in patients with Fasciola hepatica infection during an outbreak occurring in La Palma, Pinar del Río, in the West Province of Cuba. Stool and serum samples were collected from 67 patients and 40 healthy subjects. Stool samples were studied by a simple gravity sedimentation technique and an ES78 sandwich enzyme-linked immunosorbent assay (ELISA) for observation of eggs and detection of parasite coproantigens, respectively. Serum samples were also studied by the ES78 sandwich ELISA and an indirect ELISA to detect circulating antigens and antibodies, respectively. At the beginning of the study, 8 of 67 patients had patent infections and 59 had prepatent infections, which was determined by the recent consumption of lettuce contaminated with metacercariae of F. hepatica, the presence of clinical symptoms, and the absence of Fasciola eggs in their stools. Patients with prepatent infections were monitored by all techniques until patency. Circulating antigens were not detected in patients with patent infections. However, coproantigens were clearly detected in all patients with patent infections. On the other hand, 28.8% of patients with prepatent infections tested positive for circulating antigens and 81.4% tested positive for coproantigens in the first stool sample studied. Only two other coproantigen determinations were necessary to diagnose 93.2% of the patients. While circulating antigen levels diminished in all patients during the infection, coproantigen levels increased. The present study demonstrates that the ES78 sandwich ELISA is a better tool than parasitological examination for diagnosis of active early infection, since by the combination of the circulating-antigen detection assay and the coproantigen detection assay 91% of patients were able to be diagnosed at the beginning of the study. In contrast, a coprologic analysis repeated over several weeks was necessary to diagnose 100% of the patients.

Animals↗
PubMed1998

Cocaine use among heroin users in Spain: the diffusion of crack and cocaine smoking. Spanish Group for the Study on the Route of Administration of Drugs.

STUDY OBJECTIVE: To describe the prevalence and patterns of use of crack and cocaine hydrochloride among heroin users in Spain. To explore if the expansion of heroin smoking is accompanied by a similar phenomenon for cocaine. DESIGN: Cross sectional study in 1995. Face to face interviews using a structured questionnaire. SETTING: Three cities with different prevalences of heroin use by smoking: high (Seville), intermediate (Madrid), and low (Barcelona). PARTICIPANTS: 909 heroin users, 452 in treatment and 457 out of treatment. MAIN RESULTS: Last month prevalence of crack use was 62.3% in Seville, 19.4% in Madrid, and 7.7% in Barcelona. Most users in Madrid (86.5%) and Barcelona (100%) generally prepared their own crack, usually with ammonia as alkali; in Seville most users (69.7%) bought preprocessed crack. The proportion of users who began taking cocaine (crack or cocaine hydrochloride) by smoking has increased progressively since the seventies, rising to 74.1% in Seville, 61.5% in Madrid, and 28% in Barcelona in 1992-1995, with the earliest increase in Seville. The factors associated with crack use were: residence in Seville (odds ratio (OR) = 16.3), cocaine hydrochloride use mainly by smoking (OR = 5.0), by sniffing (OR = 2.7) or by injecting (OR = 2.5), heroin use mainly by smoking (OR = 2.8) and weekly use of cannabis (OR = 1.9). CONCLUSIONS: In Spain smoking cocaine may be progressively diffusing from the south west to the north east, similar to what has happened with smoking heroin, but beginning later in time. The factors associated with smoking cocaine are basically ecological or cultural in nature (characteristics of the available drugs and the main route of heroin administration in each city).

Administration, Inhalation↗
PubMed1998

Parotid metastasis from renal clear cell adenocarcinoma. An unusual site for metastasis.

Metastasis to the parotid region is rare, and originates primarily from head and neck squamous cell carcinoma and melanoma of the skin. Renal clear cell adenocarcinoma has considerable metastatic potential and the parotid gland is one possible destination. Histopathologic study is important to differentiate this entity from primary clear cell parotid neoplasm.

Biopsy, Needle↗
PubMed1998

Partial characterization of the epitope on excretory-secretory products of Fasciola hepatica recognized by monoclonal antibody ES78.

This report contains a partial characterization of the epitope recognized by monoclonal antibody (MAb) ES78 produced against excretory-secretory (ES) antigens of Fasciola hepatica. ES78 is currently used for the detection of ES antigens in serum and stool samples of cattle and humans with fasciolosis, using a highly sensitive and specific sandwich enzyme-linked immunosorbent assay (ELISA). The epitope was characterized by periodate oxidation, alkaline borohydride reduction, trichloroacetic acid precipitation, beta-mercaptoethanol treatment, and enzymatic proteolysis. These results, together with those of the 2-site ELISA, lectin immunoassays, and beta-galactosidase digestion, showed that MAb ES78 reacts with a partly protein/partly carbohydrate antigenic determinant that is found on several ES molecules of adult specimens of F. hepatica and contains at least 1 disulfide bond and beta-galactose probably as galactose-beta(1-3)-N-acetylgalactosamine disaccharide.

Animals↗