PubMed Health⌕ Search

Biomedical subjects

H Castro

Publications and source records attributed to H Castro.

16 recordsLinked to original sources
PubMed2005

Amphipod acute and chronic sediment toxicity assessment in estuarine environmental monitoring: An example from Ria de Aveiro, NW Portugal.

This paper presents a comprehensive estuarine sediment toxicity survey, using acute and full life-cycle tests with an indigenous species, the amphipod Corophium multisetosum. In the acute test, adult specimens were exposed to sediments from 144 sites for 10 days. In the full life-cycle test, 5-7 days old specimens, obtained in laboratory cultures, were exposed during 21 days to sediments from 56 sites. Three endpoints were considered: survival, for the acute and the chronic test and fecundity (number of gravid females per replicate at the end of the exposure) and growth (weight increase), for the chronic test. In the acute tests, adult survival was high overall and almost no stressed areas could be recognized in the estuary. This image was not reflected by the chronic endpoints, in particular growth and fecundity, which, corrected for the number of survivors, was the most affected descriptor. The chronic data could not be related to the baseline sediment variables analysed (grain-size, total organic content and redox potential), suggesting that these play no part in the biological responses. Results indicate that a tiered sediment bioassessment approach including an initial comprehensive ecotoxicological screening phase should not rely solely upon acute responses, although these are obtained from simpler and more rapid laboratory testing procedures.

Amphipoda↗
PubMed2003

Identification of antibodies to Leishmania silent information regulatory 2 (SIR2) protein homologue during canine natural infections: pathological implications.

Dogs are the domestic reservoir of zoonotic visceral Leishmaniasis caused by Leishmania infantum in the Mediterranean basin and thus constitute an important health problem in both human and veterinary medicine. Until vaccines become available, conventional measures such as epidemiological surveillance including reservoir control will be among the practical options for prevention and containment of the disease. We have recently characterised novel Leishmania sp. genes encoding parasite proteins named (LmS3a: homologous to mammalian ribosomal protein S3a; LmSIR2: homologous to the silent information regulatory 2 protein family; LimTXNPx: homologous to the peroxiredoxin family with N-terminal mitochondrial leader sequence) that may contribute to the host immune dysfunction in murine experimental Leishmaniasis. In the present study we have investigated the humoral responses against the parasite antigens in groups of L. infantum-infected dogs with different clinical status: symptomatic and asymptomatic with DTH positive or negative test. The determination of immunoglobulin (Ig) isotypes revealed high levels of total IgG in both symptomatic and asymptomatic animals when compared to IgM. Furthermore, the IgG2 appeared to be the predominant subclass of Ig present in the sera of infected animals particularly in the case of symptomatic dogs. The IgG subclass reactivity analysis revealed a broad specific recognition range of parasite recombinant antigens. Interestingly, differential profiles of IgG1 and IgG2 antibody reactivity were observed in asymptomatic and symptomatic dogs. The LmSIR2 protein was found to be a highly reactive molecule with IgG2 from most of the asymptomatic and symptomatic animals. Considering the fact that LmSIR2 secreted by the parasites can be bound and taken up by neighbouring cells, the latter could be a target for anti-LmSIR2 antibodies and this may contribute to the immunopathological alterations and host tissue damage. The implications of these observations in the pathogenesis of Leishmaniasis are discussed.

Animals↗
PubMed2003

Cellular localization of calcium, heavy metals, and metallothionein in lobster (Homarus americanus) hepatopancreas.

This investigation combines confocal microscopy with the cation-specific fluorescent dyes Fluo-3 and BTC-5N to localize calcium and heavy metals along the length of intact lobster (Homarus americanus) hepatopancreatic tubules and isolated cells. A metallothionein-specific antibody, developed in mollusks with cross-reactivity in crustaceans, showed the tissue-specific occurrence of this metal-binding protein in several organ systems in lobster and in single cell types isolated from lobster hepatopancreas. Individual lobster hepatopancreatic epithelial cell types were separated into pure single cell type suspensions for confocal and antibody experiments. Intact hepatopancreatic tubules showed high concentrations of both calcium and heavy metals at the distal tips of tubules where mitotic stem cells (E-cells) are localized. In addition, a concentrated distribution of calcium signal within isolated single premolt E-cells in solution was disclosed that might suggest an endoplasmic reticulum compartmentation of this cation within these stem cells. Both E- and R-cells showed significantly (P < 0.05) greater intracellular calcium concentrations in premolt than intermolt, suggesting the accumulation of this cation in these cells prior to the molt. Antibody studies with lobster tissues indicated that the hepatopancreas possessed 5-10 times the metallothionein concentration as other lobster organ systems and that isolated E-cells from the hepatopancreas displayed more than twice the binding protein concentrations of other cells of this organ or those of blood cells. These results suggest that crustacean hepatopancreatic stem cells (E-cells) and R-cells play significant roles in calcium and heavy metal homeostasis in this tissue. Interactions between the four hepatopancreatic cell types in this regulatory activity remain to be elucidated.

Aniline Compounds↗
PubMed2002

A study of relative horn fly, Haematobia irritans (Diptera: Muscidae), abundance on Holstein steers and steers of two Holstein crosses.

A study was performed to determine if the number of horn fly (Haematobia irritans) adults differ significantly on Holstein (black and white coat color), Holstein x Holstein Friesian (black and white coat color) and Holstein x Jersey (black coat color) steers, 10-12 months old at the onset of the study. All steers were run together on lucerne paddocks and the number of flies counted at 30-day intervals from September 2000 to August 2001. No significant differences (P > 0.05, test of Kruskal-Wallis) were found in fly numbers, even in the period April-May 2001 when the infestation reached its peak. We were unable to demonstrate that coat color influenced horn fly abundance in the present study. It appears that none of the biotypes evaluated had any advantage for natural control of H. irritans.

Animals↗
PubMed2001

Methodological development of an index of coastal water quality: application in a tourist area.

With the aim of obtaining an index of coastal water quality, a methodological procedure based on numerical classification and discriminant analysis is presented. The procedure was applied to nutrient data (ammonia, nitrite, nitrate, and phosphate) analyzed along the coastal waters of a Spanish tourist area. Using numerical classification, three levels of nutrient loading were revealed, characterizing oligotrophic, mesotrophic, and potentially eutrophic waters. Discriminant analysis was shown to be an effective methodological tool in the discrimination between trophic groups. For every group, the discriminant procedure generated the centroids. The centroids representing oligotrophic and potentially eutrophic conditions were used to establish the two extremes of the continuum of mesotrophic conditions in these coastal waters: Standardizing values from -1 to 1, the centroids for oligotrophic and potentially eutrophic waters yielded an interval that defined the range of mesotrophic conditions. This interval is proposed as a water quality index. The ability of the coastal water quality index to successfully predict mesotrophic conditions was proved with random samples.

Environmental Monitoring↗
PubMed2001

Application of the Kohonen neural network in coastal water management: methodological development for the assessment and prediction of water quality.

Kohonen neural network (KNN) was applied to nutrient data (ammonia, nitrite, nitrate and phosphate) taken from coastal waters in a Spanish tourist area. The activation maps obtained were not sufficient to evaluate and predict the trophic status of coastal waters. To achieve this aim, a new methodology is proposed which uses as its starting point the activation maps obtained from KNN. Firstly, to evaluate the trophic status of the coastal waters, it consists of the development of a quadrat system which enables a better classification than the traditional classification based simply on standardized data. The new classification allows clear differentiation of water quality within the mesotrophic band. Secondly, and in order to use the activation maps as predictive tools, the trophic classification, obtained from activation maps, was transposed onto new activation maps. To do this, the activation maps of the sampling points which defined each trophic group were superimposed. To avoid unnecessary complexity and to facilitate the process, this superimposition was undertaken only where the frequency exceeded 0.05. In this way, four frequency maps related to the trophic status of coastal waters (potentially eutrophic, high mesotrophic, low mesotrophic and oligotrophic) were obtained. There was no loss of relevant information in the new maps thus obtained. These frequency maps served as the basis for the successful prediction of the trophic status of random samples of coastal waters. This methodology, based on KNN, is proposed as a tool to aid the decision-making in coastal water quality management.

Environmental Monitoring↗
PubMed2001

Chemicals with sweet aroma descriptors found in Portuguese wines from the Douro region: 2,6,6-trimethylcyclohex-2-ene-1,4-dione and diacetyl.

2,6,6-Trimethylcyclohex-2-ene-1,4-dione (TMCHD), a norisoprenoid with a sweet honey aroma descriptor, is reported for the first time as a minor constituent of single-varietal table and fortified wines from the demarcated Douro region. Olfactory gas chromatography (GC-O) of a volatile wine extract, previously isolated by preparative gas chromatography, indicated the presence of a zone containing an intense honey descriptor. The targeted odor compound was identified by GC-MS, GC-O, and Kovats index. Quantitative analysis using a selected characteristic ion (m/z 96) indicated that young Douro fortified wines from the 1997 vintage contained up to 4 microg/L TMCHD. The sweet honey sensory threshold limit for TMCHD in a model Port wine solution was found to be 25 microg/L. TMCHD is therefore only likely to contribute as a collective element to Port wine aroma. The wine volatile diacetyl was identified as a strong contributor to the sweet caramel aroma descriptor often associated with Port.

Chromatography, Gas↗
PubMed1997

Identification of sites of injury in Lactobacillus bulgaricus during heat stress.

Heat resistance of Lactobacillus bulgaricus in skimmed milk at 62 degrees, 64 degrees, 65 degrees and 66 degrees C was studied. The response to increasing temperatures in this range was not linear, with temperatures at 65 degrees C and above giving a lower survival rate than would be predicted from experiments at lower temperatures. To identify sites of injury at these temperatures, chemical markers were used. Heating at 64 degrees C and below resulted in damage to the cytoplasmic membrane. At temperatures of 65 degrees C and above chemical markers also indicated damage in the cell wall and proteins. Using differential scanning calorimetry analysis of whole cells of Lact. bulgaricus seven main peaks were observed (1-51, m1-61, m2-73, n-80, p-89, q-100, r-112 degrees C). Three of these peaks (l(r), m(r) and p(r)) were the result of reversible reactions. Analysis of cell fractions identified the cell structure involved in giving rise to each of the three reversible peaks; l(r), cell membrane lipids, m(r), ribosomes, and p(r), DNA. The evidence presented in this paper shows that irreversible reactions in the cell ribosomes are a critical site of damage in Lact. bulgaricus during heat stress in liquid media at 65 degrees C and above.

Animals↗
PubMed1994

[Mucocutaneous pathology in HIV infection].

Several infectious, neoplastic or inflammatory skin diseases, may be early manifestations of HIV infection. We reviewed the clinical data of 226 HIV seropositive male patients with cutaneous disease, from a total of 337 inpatients at the Infectious Diseases Unit--Department of Medicine 1--Curry Cabral Hospital, from 1985 to 1991. Some considerations are made about the most common dermatological disorders: oral candidiasis, seborrheic dermatitis, Kaposi's sarcoma, herpes simplex infection, drug-related skin disorders, herpes zoster and dermatophytosis. The high prevalence of cutaneous manifestations in HIV infection, the uncommon clinical findings and their occasional therapeutic problems, makes an early diagnosis essential.

AIDS-Related Complex↗
PubMed1989

[Evaluation of the reliability of anthropometric measures].

As part of the Early Malnutrition and Its Effects on Youth Project, a study of the reliability of anthropometric measures was carried out through the re-measurement of 226 adolescents of the rural area of Guatemala. In all anthropometric variables, the intra-measure coefficients of reliability were higher than 0.96 and the inter-measure coefficients of reliability higher than 0.91. A significant effect of the measure was found, suggesting the existence of systematic differences among measures. This information will permit corrections by measure effect in the analysis of data. The effect of different grades of "data editing" and "validity, reliability and agreement check", of measures was evaluated. The conclusion was that even though the persons in charge of measurements were trained and supervised, the deletion of values outside ranks did not result in an appreciable decrease of the technical error of measurement. As expected, data editing and validity carried out through the comparison of two measurements taken from each subject and eliminating those whose differences were classified as error according to statistical criteria, decreased the technical error of measurement, in most of the variables measured. Nevertheless, with the exception of one of the variables, this decrease was not marked. This indicates that the technical error of measurement obtained from all the subjects, many of whom were not re-measured, was within acceptable ranks. Results of the study demonstrate the importance of including re-measurement of a certain percentage of subjects when designing anthropometric studies. This will allow evaluation of the reliability of measurements, identification of bias due to measurements, and their correction.

Adolescent↗
PubMed1982

Cesarean section IUD insertion.

A trial was carried out on 154 selected volunteers who underwent cesarean section and then received an ML Cu 250 IUD during the operation. 56% of the operations were planned while 44% were not. The IUD was inserted in 65, 80, and 9 cases in the 1st, 2nd, and 3rd cesarean section, respectively. The patients were followed-up after 1, 3, 6, 12, and 24 months. Hospitalization time and postoperative morbidity did not increase with device insertion. Maternal lactation was not altered. 8% of the patients had postpartum bleeding which lasted more than 40 days. At the 1 year examination, 52% of the patients were menstruating normally while at 2 years, the percentage had increased to 62.5%. The acceptability, continuity, and efficiency of the contraceptive procedure proved successful. There were only 4 cases (2.6%) in which the device had to be removed for medical reasons (due largely to endometritis) and 8 cases (5.2%) because of patient desire (menstrual abnormalities). Spontaneous expulsion of the IUD occurred in 4 cases (2.6%). As of the present time, no pregnancies have been detected. The cesarean section insertion of an ML Cu 250 IUD produced excellent results and further, more widespread use is suggested.

Endometritis↗
PubMedDate not supplied

[Distribution of capsular types and antimicrobial susceptibility of Streptococcus agalactiae causing infections in Argentina].

Streptococcus agalactiae is an endogenous bacterium that has emerged in the last 20 years as an etiological agent in both neonatal and perinatal infections, and in immunocompromised patients. The differentiation of the capsular polysaccharide, the presence of surface proteins c, X, R, and molecular methods allow classification in serotypes and genotypes. This identification is a useful tool for epidemiological purposes and virulence studies in this bacterium. The objective of this work was to study the serotypes and the antimicrobial susceptibility of isolates recovered from invasive diseases in different areas of Argentina. In the analyzed sample a fair predominance of Ia and III serotypes was recovered, followed by II and IV serotypes. All the isolates were found to be sensitive to penicillin. A 6% of resistance to erythromycin and a 4.5% to clindamycin were detected. In three of the isolates, constitutive MLS phenotype (resistance to macrolides, lincosamins and streptogramins) was founded, while in the remaining one, inducible MLS phenotype was detected. These results stress the importance of conducting a surveillance of the prevalent serotypes in our country with the goal of future prevention of this disease with an effective vaccine. The knowledge of the antimicrobial susceptibility profile will be also important to obtain therapeutic success in the treatment.

Argentina↗