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Biomedical subjects

M T Costa

Publications and source records attributed to M T Costa.

At least 19 recordsLinked to original sources
PubMed2002

A case-control study of the risk factors for cystic echinococcosis among the children of Rio Negro province, Argentina.

In 1984 the prevalence of cystic echinococcosis (CE) in Rio Negro province in central Argentina reached alarming levels, with almost 6% of children aged 7-13 years infected with the causative agent, Echinococcus granulosus. Although the control activities developed between 1980-2000 have now lowered the prevalence of infection in this age-group to 1.1%, transmission of E. granulosus has clearly not ceased. The aim of the present study was to identify possible flaws in the control programme and the risk factors associated with CE. The 24 cases and 66 controls used were identified during a survey of the 1,070 schoolchildren attending 12 schools in Ingeniero Jacobacci, Rio Negro province. In interviews based around a standardized questionnaire, the adult female with responsibility for each subject (usually the mother but sometimes a grandmother or guardian) was asked 70 questions about the child and his or her immediate family, their contact with dogs and relevant environmentmental factors, and their level of contact with the control programme. Univariate and multivariate analyses were used to determine odds ratios (OR) and their 95% confidence intervals (CI). The main risk factors found to be significantly associated with CE were having a family member with the disease (OR = 3.11; CI = 0.92-10.47), spending the first years of life surrounded by a large number of dogs (OR = 2.11; CI = 1.2-3.5), and having a father who slaughtered sheep at his workplace (OR = 1.14; CI = 1.04-1.24). Obtaining drinking water from a tap (OR = 0.28; CI = 0.08-1.01) also remained in the final model, as a protective factor.

Adolescent↗
PubMed2001

Localization, purification and specificity of the full-length membrane-bound form of human recombinant alpha 1,3/4-fucosyltransferase from BHK-21B cells.

Fucosyltransferase III [galactoside 3(4)-L-fucosyltransferase; EC 2.4.1.65] (FT3) is a Golgi type II membrane protein that catalyses the synthesis of fucosylated Lewis motifs that are associated with cell-adhesion events and are differentially expressed during cell differentiation. In the present work, the full-length membrane bound form of FT3 has been expressed in baby hamster kidney cells. The enzyme has been found in the trans-Golgi and trans-Golgi network (TGN) of the transfected cells, where it appeared as monomers and dimers, but not as oligomers with high molecular masses. Therefore oligomerization is not the basis for correct localization of FT3 in the Golgi. The enzyme has been purified, with a final yield of 2% and a total purification of 2900-fold, by DEAE-Sepharose, SP-Sepharose, GDP-Fractogel and Superdex 200 chromatography. The purified enzyme showed a clear preference for the Gal beta 3GlcNAc motif in oligosaccharides conjugated with the hydrophobic tail (CH(2))(3)-NHCO-(CH(2))(5)-NH-biotin. Substitution of galactose with alpha 2-linked fucose or alpha 2,3-linked N-acetylneuraminic acid yielded a 1.9-fold increase or a 43% decrease in activity respectively. The enzyme showed no activity towards asialofetuin, a glycoprotein containing the Gal beta 3GlcNAc acceptor motif. Therefore it has been concluded that the membrane-bound form of FT3 is present in the Golgi and the TGN in an equilibrium of monomers<-->dimers, which might fucosylate glycans from glycolipids, but not from glycoproteins.

Animals↗
PubMed2001

Ovine Echinococcus granulosus transmission dynamics in the province of Rio Negro, Argentina, 1980-1999.

In this work, the impact of a hydatidosis control programme for dogs on the intermediate ovine host was specifically analysed to determine the levels of prevalence achieved and the dynamics of parasite transmission, as well as to evaluate the quality of diagnostic systems in slaughterhouses. A field study was conducted in four slaughterhouses (Valcheta, Los Menucos, Jacobacci, Bariloche) that process animals coming from all the departments within the work area. The control programme for dogs entailed treating dogs with 5 mg/kg praziquantel at 2-month intervals for 20 years. Sample size was determined with a 10% error margin and a 95% significance level. Harvested viscera (liver, lungs, kidneys) were preserved in 5% formaldehyde and sent to the laboratory for diagnostic confirmation of both positive and negative specimens. The 61% initial prevalence dropped to 18.3% at the end of the 10-year period, observed differences proving significant (Chi-square=15.454, P=0.00). There were statistically significant increases in infection prevalence with age (Pearson's Chi-square=133.61, P=0.00). Overall, 37.2% of hydatidosis cases diagnosed in slaughterhouses were considered non-hydatid by histological study. On the other hand, 1.1% of those diagnosed as healthy were found to be infected with hydatidosis. The number of hydatid cysts per animal increased with age: 0.04 in lambs and 1.22 in adults (linear regression equation, -0.0539+0.0127 x age), whereas the average for the whole period was 3.7% in lambs and 20.5% in adults. Viability studies indicated that 63.8% of parasitised animals had viable cysts, out of which 53.3% were fertile. Diagnosis of infection in sheep made by means of an adjusted statistical design and with histological confirmation of the presumptive diagnosis made in slaughterhouses demonstrated the flaws of the official systems for epidemic surveillance of hydatidosis. However, there was no overall significant difference in slaughterhouse and laboratory data.Ro was 0.53 and could imply a decrease in reproductive capacity of the parasite and steady state extinction.

Abattoirs↗
PubMed2000

Rate of infection and of reinfection by Echinococcus granulosus in rural dogs of the province of Rio Negro, Argentina.

Hydatidosis (cystic echinococcosis) constitutes a serious public health problem in the Province of Rio Negro, Argentina. In the present work it was intended to evaluate the prevalence of the canine echinococcosis in rural areas of the Province of Rio Negro and studied the reinfection rate in dogs after treatment with Praziquantel during the period 1980-1997. A total of 496 dogs were studied in 18 canine concentrations in order to establish the initial prevalence rate which was 42.3%. From 1980 onward dogs should have been systematically treated with anthelmintic every 2 months in rural areas and every 6 months in urban areas. We estimated that approximately 65% of dogs were treated. To determine the reinfection rate, 476 dogs (1984) and 598 dogs (1996) were studied after anthelmintic treatment during two sequential time periods (0-45; 46-90 days). In both cases treated animals were compared with untreated dogs. Prevalences were 3.5%, 6.7% and 21.3% in 1984 and 0.8%, 4.0% and 10.0% in 1996. For the purpose of surveillance a total number of 21,444 dogs were studied during 18 years. Prevalence of Echinococcus granulosus decreased significantly in the first year from 42.3% to 6.1%.

Animals↗
PubMed1995

Molecular analysis of three patients with interstitial deletions of chromosome band 14q31.

Two patients and one three generation family with interstitial deletions of distal chromosome band 14q31 are described. The deletions were initially identified by chromosome analysis; we have used highly informative simple sequence repeat polymorphisms to define the deletions at the molecular level. This analysis also establishes the parental origin of the deleted chromosome. One of the patients was initially described as having a terminal deletion of chromosome 14 from 14q31 to 14qter; we show here that this child has instead an interstitial deletion of band 14q31. The smallest deletion involves a single anonymous DNA marker and is associated with an almost normal phenotype. The two patients with larger deletions have phenotypes similar to those seen in previously described cases of interstitial deletions of chromosome 14, including minor dysmorphic features and developmental delay. Delineation of these deletions allows the ordering of markers within the 14q31 region, in which the gene for the degenerative neurological disorder Machado-Joseph disease is localised.

Abnormalities, Multiple↗
PubMed1993

Identification and characterization of sporadic and inherited mutations in exon 31 of the neurofibromatosis (NF1) gene.

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders in humans, and presents with a variety of clinical symptoms, which are highly variable in expression. The mutation rate for NF1 is high, with as many as half of all cases resulting from new mutations. Although the NF1 gene has been cloned and its cDNA sequence determined, the specific role of the NF1 gene product in contributing to the NF1 mutations is one of the first steps in correlating genotype with clinical symptoms of the disease. In this paper we describe two independent mutations in exon 31 of the NF1 gene identified following polymerase chain reaction (PCR) amplification, heteroduplexing, and single strand conformational polymorphism (SSCP) analysis. One is a novel insertion that segregates with the disease phenotype in that particular family (5852insTT), while the other is a further example of the sporadic, recurrent C-->T mutation previously described in the literature (C5842T). The relationship between these mutations and clinical features of NF1 presented by the patients will be discussed.

Adolescent↗
PubMed1989

Contractures in patients with Williams syndrome.

Williams syndrome is a multisystem disorder, including a characteristic facies and habitus. Intellectual, neurologic, and cardiovascular dysfunction occur; vascular disease may be progressive. Joint contractures affected 10 of a group of 20 children and young adults. In 3 of 10 patients, the contractures were severe enough to interfere with daily activities; in 3 the effect was only moderate. The contractures developed in early childhood and usually did not improve or worsen with time. Large and small joints were affected and usually were symmetrical. Their occurrence did not correlate with vascular disease. The contractures could not be attributed to a neurologic cause.

Adolescent↗
PubMed1985

Diamine oxidase content in urine of patients with renal failure.

Diamine oxidase activity was determined in twenty-seven samples collected from normal subjects and from patients with renal failure. The enzyme activity was absent or very low in the urine samples of normal subjects. The highest diamine oxidase activity was found in the patients affected with nephrosis, the Fanconi syndrome and renal transplantation, showing a relationship between urinary enzymatic activity and tubular damage, in accordance with the localization in the convoluted tubules.

Amine Oxidase (Copper-Containing)↗
PubMed1981

Skin reactions to bug bites as a result of xenodiagnosis.

Cutaneous allergic reactions to bites of two bug species Triatoma infestans and Dipetalogaster maxima, were studied in an area where T. infestans is the local domestic vector. While more delayed skin reactions occurred with the indigenous vector, reactions also occurred with D. maxima. Repeated exposure to D. maxima produced more intense immediate skin reactions. First-stage D. maxima bugs produced a lower frequency and intensity of skin reaction. It is concluded that further work on this problem is necessary as it prejudices the use of xenodiagnosis in field surveys.

Animals↗
PubMed1977

Report of large kinship with familial translocation between chromosomes 21 and 22.

This paper reports a large kinship with a familial (21;22) translocation occurring in both the balanced and the unbalanced states. Recurrence risks for the (21;22) translocation in the unbalanced state are high (14%) for the offspring of female carriers as compared with those for the offspring of male carriers (4%), but the offspring of male carriers appear to have a much higher risk (50%) of being balanced carriers than those of female carriers (30%).

Chromosomes, Human, 21-22 and Y↗
PubMed1977

On the nature of chromophore in pig kidney diamine oxidase.

The nature of the 500-nm chromophore in pig kidney diamine oxidase was investigated by absorption spectroscopy and fluorescence in the presence of various chelating or carbonyl-specific reagents. From the spectroscopic measurements the following conclusions can be drawn. First, the 500-nm absorption band is not due to copper, the reduction of which is not related to the disappearance of this band. Second, phenylhydrazine and cycloserine give rise, upon reaction with the enzyme, to absorptions very similar to those of a pyridoxal enzyme, aspartate aminotransferase. Third, these enzyme derivatives are unexpectedly non-fluorescent. Copper removal, obtained after prolonged incubation of cycloserine-treated enzyme in the presence of reducing and chelating agents, leads to a fluorescence similar to that of cycloserine-aspartate transminase. It is proposed that copper is coordinated to the postulated pyridoxal phosphate of diamine oxidase through the pyridine nitrogen.

Amine Oxidase (Copper-Containing)↗