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Biomedical subjects

C A Costa

Publications and source records attributed to C A Costa.

At least 37 records · Page 2Linked to original sources
PubMed1997

Oxidative tissue response promoted by 5-aminolevulinic acid promptly induces the increase of plasma antioxidant capacity.

The heme precursor 5-aminolevulinic acid (ALA), acting as a prooxidant, has been proposed to underlie the clinical manifestations of various porphyric disorders. Accordingly, ALA-generated oxyradicals where shown to cause oxidative lesions in biomolecules and isolated cell organelles and to release iron from ferritin. In rats, administered ALA triggered oxidative stress in liver, brain and red muscles. We now study the correlation between the plasma antioxidant capacity and tissue oxidative damage, after acute (one and two doses) and prolonged (eight doses) ALA treatment of rats (one dose of ALA = 40 mg/kg body weight). The in situ spontaneous chemiluminescence intensity increased 5-fold in brain, 50% in liver and 4-fold in soleus muscle upon two dose-treatment, indicating tissue response to oxidative injury by ALA. Chemiluminescence reached the highest intensity after one or two doses of ALA and decreased after eight doses in all tissues. The plasma trapping capacity, evaluated by the luminol/2-amidinopropane system, gave a parallel response: maximum values after two doses and decreased values after prolonged treatment. After eight doses, the ALA concentration was found to be 3-fold above the normal value in plasma, 48% higher in liver and 38% higher in total brain. These data indicate that the plasma antioxidant system responds to ALA treatment and is correlated with tissue chemiluminescence. In vitro studies showed that ALA does not interfere with the antioxidant plasma capacity, neither promoting oxidation of plasma elements nor binding to plasma proteins.

Amidines↗
PubMed1997

Correlation between plasma 5-aminolevulinic acid concentrations and indicators of oxidative stress in lead-exposed workers.

5-Aminolevulinic acid (ALA), a heme precursor accumulated in acute intermittent porphyria and lead poisoning, undergoes metal-catalyzed aerobic oxidation at physiological pH to yield reactive free radical species (O2., HO., and ALA.). We analyzed the relationships between plasma ALA concentrations, blood concentrations of lead, protoporphyrin IX (PP-IX), superoxide dismutase (SOD), and methemoglobin (metHb), and urine chemiluminescence (CL) in samples collected from lead-exposed workers. All variables measured were substantially (P < 0.01) higher (2-8-fold) in the lead-exposed workers (n = 60). Plasma ALA concentrations were, on average, 6-fold higher in lead-exposed workers. We observed positive linear relationships between ALA and lead (r = 0.992), ALA and PP-IX (r = 0.891), ALA and metHb (r = 0.984), lead and SOD (r = 0.948), ALA and urine CL (r = 0.987), and lead and PP-IX (r = 0.993). These data are consistent with our free radical hypothesis for lead poisoning, where ALA distribution to and accumulation in several organs may trigger oxidative stress responses.

Adolescent↗
PubMed1995

Placental bed lesions and infant birth weight in hypertensive pregnant women.

Sixty pregnant women with systemic arterial hypertension, whose pregnancies were interrupted by cesarean section at the Maternity Ward of Hospital de Clínicas de Porto Alegre between May 1989 and October 1990, were examined. Specimens of the placental bed were collected by biopsy and the presence of acute atheromatosis and/or fibrinoid necrosis was investigated. The patients were divided into two groups according to the presence or absence of vascular lesions. The biopsy findings of the placental bed were compared with adequate weight at birth related to gestational age, and to the following clinical parameters of the mother: arterial blood pressure, serum creatinine, serum uric acid and proteinuria. Twenty-seven (45%) patients presented vascular lesions in the placental bed compatible with acute atheromatosis and/or fibrinoid necrosis. The presence of vascular changes in the placental bed correlated significantly to diminished weight of the newborn, in terms of the mean weight and in terms of small-for-gestational-age infants, non-nephrotic proteinuria ( > or = 300 mg/24 h) and increased levels of uric acid ( > 5.5 mg/dl).

Adult↗
PubMed1994

Fine needle aspirative biopsy of the liver in HBsAG-positive patients with end-stage renal failure.

HBsAg-positive patients with end-stage renal failure have a high prevalence of asymptomatic chronic hepatitis. In order to determine the usefulness of hepatic cytology in the diagnosis of liver disease, the findings of hepatic needle core biopsy (NCB) and fine needle aspirative biopsy (FNAB) were compared in 15 HBsAg-positive uremic patients. The patients, aged 42 +/- 12 years, 14 males, were on hemodialysis for periods ranging from 13 to 105 months. The NCB was processed by standard histologic and immunohistochemical techniques and FNAB by the conventional technique, using the total corrected increment score (TCI). Plasma samples were collected for evaluation of hepatic function and for viral serologic tests. In 15 patients a diagnosis was made by NCB: normal, 7 cases; chronic persistent hepatitis, 4 cases; and chronic active hepatitis, 4 cases. When the patients were allocated into two groups according to the severity of the liver histologic findings [group I--minor changes (normal+chronic persistent hepatitis), 11 patients; group II--major changes (chronic active hepatitis), 4 patients], statistically higher values were found in the major changes group for alanine aminotransferase (49 +/- 33 vs. 24 +/- 11, p = 0.04), gamma-glutamyl transpeptidase [148 +/- 53 vs. 38 +/- 28, p < (minor) 0.02] and TCI (3.7 +/- 1.2 vs. 2.5 +/- 0.8, p = 0.04). In conclusion, liver FNAB can be useful as a screening procedure for the identification of liver histologic changes (minor or major) in uremic HBsAG-positive patients.

Adult↗
PubMed1994

[Helminth parasites of capybaras (Hydrochaeris hydrochaeris) on sub-region of Nhecolândia, Pantanal, Mato Grosso do Sul].

A sequence of 23 necropsies was carried out on capybaras (Hydrochaeris hydrochaeris) from the central area of Nhecolândia, Pantanal region, state of Mato Grosso do Sul, Brazil, from December 1984 to December 1986. The helminths identified and their respective prevalences and mean intensity were: Trichostrongylus axei--60.9 and 14, Viannella hydrochoeri--95.6 and 1031, Strongyloides chapini--47.8 and 1014, Yatesia hydrochoerus--44.4 and 6, Cruorifilaria tuberocauda--40.0 and 8, Capillaria hydrochoeri--86.9 and 156, Protozoophaga obesa--100.0 and 7212, Taxorchis schistocotyle--56.5 and 43, Hippocrepis hippocrepis--34.8 and 3832, Nudacotyle tertius--8.7 and 133, Monoecocestus hydrochoeri--54.5 and 62, and Monoecocestus hagmanni--80.0 and 75. Y. hydrochoerus was registered for the first time in Brazil. The helminths C. tuberocauda, V. hydrochoeri, S. chapini and H. hippocrepis has characteristics that induce clinical and subclinical parasitosis. Although multiple infections predominated, no interactions among the helminth parasites of the same organ were observed. The prevalences and abundances of S. chapini, Y. hydrochoerus and C. hydrochoeri were influenced by the age of the host. So, S. chapini presented higher values in young animals, while Y. hydrochoerus and C. hydrochoeri showed an opposite tendency.

Animals↗
PubMed1992

Victoria M. Trasko: champion of state-based surveillance of occupational diseases in the United States, 1937 to 1971.

Victoria M. Trasko (1907-1979), a relatively unknown figure to many currently practicing occupational health specialists, was a pioneer in state-based surveillance of occupational diseases in the United States. To highlight her accomplishments during her career with the United States Public Health Service from 1937 to 1971, this report briefly reviews her publications on occupational disease surveillance. Her span of work includes guidelines for state industrial hygiene programs, numbers of workers in state occupational health programs, compilation of state and local laws related to industrial hygiene, proposals for standardized reporting of occupational disease, and analysis of trends in workers' compensation and mortality statistics for occupational diseases. She pilot tested the first state-based model system for occupational disease reporting in the United States. She documented the great difficulty experienced by states in getting physicians to report cases of occupational diseases, and pointed out that surveillance of other existing data sources was worthwhile, at least for some occupational diseases. She was the first to report on the distribution of silicosis cases in the United States by state, industry, and job title. She was the first to comment on mortality trends for the pneumoconioses and to document problems in comparability between different International Classification of Disease (ICD) periods.

History, 20th Century↗
PubMed1992

Haemonchus contortus resistance to ivermectin and netobimin in Brazilian sheep.

Suffolk, Texel, Hampshire Down and Ile de France sheep from the municipalities of Porto Amazonas, Piraquara and Araucaria in the State of Paraná, and Bagé in the State of Rio Grande do Sul were brought to Sobral, State of Ceará, to be used in a cross-breeding project. On arrival they had clinical signs of nematode parasitosis, and one Suffolk female died. The animals were treated orally with ivermectin (0.2 mg kg-1) and fifteen days later with netobimin (20.0 mg kg-1). Neither drug reduced the egg counts (measured in eggs per gram, EPG) significantly, and this suggested that the nematodes in the sheep were resistant to the anthelmintics used. Haemonchus contortus was the species involved. The egg counts were reduced after oral treatment with trichlorfon (100.0 mg kg-1). Haemonchus contortus larvae obtained from these animals before trichlorfon treatment and passaged through two nematode-free sheep were used in a further experiment. Twenty 6- to 9-month-old nematode-free lambs were infected with the H. contortus larvae (10,000 per animal) and after the infection was confirmed, were randomly divided into four groups of five animals. Group I was orally treated with ivermectin at 0.2 mg kg-1, Group II with oral netobimin at 20.0 mg kg-1, Group III with oral trichlorfon at 100.0 mg kg-1 and Group IV was a non-treated control. Egg counts and faecal cultures were taken before dosing on the day of treatment and seven days later when all animals were necropsied and the nematodes were collected from the abomasa and counted.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1986

Longitudinal study of diarrhoeal disease in a peri-urban community in Manaus (Amazon-Brazil).

A 20-month longitudinal study of diarrhoeal disease was carried out in a poor peri-urban community of Manaus (Amazon-Brazil), and the attack rate of this disease ranged from 0.2 to 4.8 episodes of diarrhoea per person per year. The age group most affected was 0 to 35 months old. A probable aetiological agent was identified in 68 of the 110 faecal samples collected. The most frequent enteropathogens isolated were enterotoxigenic Escherichia coli and Giardia lamblia. Enterotoxigenic Escherichia coli was also isolated from stream-water and from flies collected inside a household.

Adolescent↗
PubMed1986

Controlled field trials of a vaccine against New World cutaneous leishmaniasis.

Two controlled, double blind field trials of a non-living promastigote vaccine against New World Cutaneous Leishmaniasis (NWCL) were conducted in 1981 and 1983 in Brazil. Brazilian Army conscripts were randomly assigned to the vaccine or placebo groups and tested during their training in the Amazon jungle, a high risk area for NWCL. The results obtained showed: no significant differences between the vaccine and the placebo groups with respect to a number of characteristics (age, race, previous contact with the jungle, etc.); no significant differences between the participants who got and who did not get NWCL during the trial, with respect to length of exposure, contact with the jungle, etc. and a reduction of 67.3 and 85.7% in the annual incidence rate of NWCL, in 1981 and 1983 respectively (although the difference between incidence rates of the disease in vaccinated and control groups in the 1983 trial was not statistically significant), among those vaccinated who had converted to a positive leishmanin skin test as compared with the placebo groups.

Adolescent↗
PubMed1979

Wild reservoirs of Schistosoma mansoni from Caratinga, an endemic schistosomiasis area of Minas Gerais State, Brazil.

Among 472 small mammals trapped in the Caratinga area of Minas Gerais, Brazil, Schistosoma mansoni infection was demonstrated in 6 of 9 Procyon, 1 of 7 Didelphis, 1 of 1 Philander, 25 of 72 Nectomys, and 16 of 383 various other rodents representing 20 species. The role of Nectomys and Procyon in maintaining endemicity needs further investigation.

Animal Population Groups↗
PubMed1978

Mastomys natalensis as an experimental host for Leishmania mexicana mexicana.

Young multimammate rats (Mastomys natalensis) can be readily infected when inoculated intradermally with the amastigotes of Leishmania mexicana mexicana. Lesions appear at the site of inoculation in the second week of infection and continue to increase in size for the first month; amastigotes can be detected during this period. In the second month, lesions begin to decrease in size and it is more difficult to detect amastigotes. Three months after inoculation, the rats show no sign of infection. The results suggest that M. natalensis could be a useful laboratory host for immunological studies on dermatotropic Leishmania and for chemotherapeutic assays.

Animals↗