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A number of reports have shown that the peripheral blood neutrophil count in many negroes is considerably lower than in white populations. This neutropenia has been ascribed previously to both genetic and nutritional causes. We have studied bone marrow reserve function and myelopoiesis in 3 negroes with neutropenia, and found these to be normal.
Glucose-6-phosphate dehydrogenase in erythrocytes of the Negro type associated with enzyme deficiency (A(-)) was separated by chromatography on a carboxymethyl-Sephadex column from the electrophoretically indistinguishable Negro variant with normal enzyme activity (A(+)). Quantitative immunologic neutralization tests indicated that the A(-) enzyme had about the same enzymatic and serological activity as the A(+) and the normal (B(+)) enzymes. The enzyme activity of the A(-) variant in young erythrocytes was similar to that in young cells from normal individuals, although the activity of the A(-) variant in unfractionated red cells was 10 to 15 percent of normal. These data indicate that the basic defect in the variant enzyme (A(-)) is a structural mutation which causes more rapid degradation of the enzyme during erythrocyte aging.
Development of a rapid screening test for atypical cholinesterase in serum enabled large-scale surveys of populations. The frequency of the heterozygous trait among Greeks, Yugoslavs, and East Indians was similar to that among United States Caucasians (2.8 to 3.3 percent). In trait frequency, U.S. Negroes were intermediate (1.05 percent) between Congolese Africans (0.29 percent) and U.S. Whites (3.3 percent). The gene was absent from or very rare in populations originating in East Asia (Taiwanese, Japanese, Filipinos, and Eskimos). Prolonged apnea during anesthesia from administration of succinylcholine caused by homozygosity for this gene, is expected to be extremely rare among populations of Negroes and East Asians.
Visual evoked potential testing was performed on 15 Negro carriers of the gene for tyrosinase positive oculocutaneous albinism in order to detect whether they have the same visual pathway decussation anomalies as do homozygotes. No subject showed 01-02 asymmetry on monocular testing, indicating that decussation follows the normal pattern. It is concluded that visual evoked potential testing is probably not useful in the detection of Negroes heterozygous for the gene for tyrosinase positive oculocutaneous albinism.
The gamma-chain structure of a homozygote for HPFH Negro type, previously described by Acquaye and co-workers, and of 3 heterozygotes of the same family has been evaluated. G gamma and A gamma chains were present in a ratio of fetal type (7/3) in the homozygote and in ratios of 2/3 and 1/1 in the heterozygotes, in agreement with data of the literature. T gamma chains were absent in all the cases. Our results, compared with those previously reported for Negro and Greek HPFH, suggest that the T gamma gene is never linked with the HPFH determinant.
The haematological indices of cord bloods from 430 South African Negro babies were determined by electronic cell counting and their haemoglobin (Hb) patterns examined by alkaline cellulose acetate electrophoresis. A fast-moving, anodal band, identified as Hb Bart's, was found in 7 (1,6%) of the specimens, this being the lowest incidence of the variant yet found in an indigenous African population. The levels of Hb Bart's ranged from 1.3 to 5.5% of the haemoglobin. These findings were confirmed by alkaline-starch gel electrophoresis and at the same time absence of the slow-moving haemoglobin, Hb Constant Spring was established. Subsequent follow-up of 4 of the infants at 4 months of postnatal life showed that the abnormal component had disappeared. The babies with Hb Bart's had a marked microcytosis and low mean corpuscular haemoglobin levels whilst their parents showed no haematological or electrophoretic signs of alpha-thalassaemia. The significance of these findings is discussed in the light of previously reported studies on various Negro groups.
In Italian and Chinese patients with the alpha-thalassemia syndromes the production of alpha-chain of normal hemoglobin is decreased relative to that of beta-chain in reticulocytes. In this study the relative rates of alpha- and beta-chain synthesis were determined in members of three Negro families with alpha-thalassemia. Two of the families had members with hemoglobin H disease and alpha-thalassemia trait, while the mother of several children with alpha-thalassemia trait in the third family was doubly heterozygous for alpha-thalassemia and an alpha-chain mutant. The alpha/beta ratios of globin synthesis in the patients with hemoglobin H disease and alpha-thalassemia trait indicated less severe biochemical defects in the peripheral blood than those previously determined in Italian and Chinese patients. In the third family, there was a heterogeneity of expression of the gene for alpha-thalassemia, including patients with normal red cell indices and synthesis ratios. These findings differ from those previously described in patients with alpha-thalassemia from other racial groups. Hydrops fetalis due to homozygous alpha-thalassemia may not occur in the Negro because of the relatively mild thalassemic defect.
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.
Stingrays of the family Potamotrygonidae are the only stenohaline freshwater elasmobranchs. Potomotrygon sp. collected from the ion-poor blackwaters ([Na(+)], [Cl(-)] and [Ca(2+)]=10-30 micro mol l(-1), pH 6.1) of the Rio Negro, Amazonas, Brazil, were ammoniotelic (91% ammonia-N, 9% urea-N excretion) and exhibited blood chemistry (Na(+), Cl(-), urea, ammonia and glucose levels and osmolality) typical of freshwater teleosts. Unidirectional Na(+) and Cl(-) influx rates, measured with radiotracers, displayed saturation kinetics. The relationships for Cl(-) and Na(+) had similar K(m) values (300-500 micro mol l(-1)), but J(max) values for Cl(-) (approximately 950 micro mol kg(-1) h(-1)) were almost twice those for Na(+) (approximately 500 micro mol kg(-1) h(-1)). Cl(-) efflux rates varied with external concentration, but Na(+) efflux rates did not. There were no differences in the kinetic variables (K(m), J(max)) for influx between animals acclimated to their native ion-poor blackwater or to ion-rich hard water, but efflux rates for both Na(+) and Cl(-) were lower in the former, yielding much lower balance points (external Na(+) or Cl(-) levels at which influx and efflux were equal). Na(+), Cl(-) and Ca(2+) uptake were all strongly inhibited by acute exposure to pH 4.0, but efflux rates and Ca(2+) binding to the body surface did not change. Na(+) influx was inhibited by amiloride (10(-4) mol l(-1)) and by two of its analogs, phenamil (4 x 10(-5) mol l(-1)) and HMA (4 x 10(-5) mol l(-1)), with the latter being slightly more potent, while Cl(-) fluxes were unaffected. Cl(-) fluxes were insensitive to DIDS (2 x 10(-5) mol l(-1) or 10(-4) mol l(-1)) and SITS (10(-4) mol l(-1)), but both influx and efflux rates were strongly inhibited by DPC (10(-4) mol l(-1)) and thiocyanate (10(-4) mol l(-1)). Ammonia excretion was unresponsive to large changes in water Na(+) concentration, but was elevated by 70% during acute exposure to pH 4.0 and transiently inhibited by approximately 50% by amiloride and its analogues. The strategy of adaptation to ion-poor blackwater appears similar to that of some Rio Negro teleosts (Cichlidae) in which low-affinity transport systems are relatively sensitive to inhibition by low pH but are complemented by low diffusive loss rates. Ionic transport systems in these freshwater elasmobranchs, although superficially similar to those in some freshwater teleosts, may bear more resemblance to their presumed evolutionary precursors in marine elasmobranchs.
The Sardo Negro cattle (SN) is the only zebu cattle breed developed in Mexico. Since its development, the selection could have led to an increase in the homozygosity level in some regions of the genome and made differentiation with other cattle populations. We aimed to identify and characterize selection signatures in SN using medium-density SNP data using four approaches: 1) Runs of homozygosity (ROH) 2) Nucleotide Diversity 3) Tajima's D and 4) the Wright's fixation index (FST). A sample of 555 SN animals genotyped for 65k SNPs was used to obtain ROH segments considered regions under selection. The FST values were estimated by comparing the sample of genotyped SN animals with samples of genotyped animals from the Gir, Brahman, and Ongole breeds. Only one region mapped to 35.78-42.51 Mb on BTA6 was considered a selection signature by the ROH method. This selection signature overlapped with the lowest diversity, negative values of Tajima's D and a diversification region between SN and the other Zebu breeds by FST. We found several candidate genes (LCORL, NCAPG, and SLIT2) related to growth and other economically important productive traits in this common region. Using the FST method, different regions, such as regions on BTA8 (8:93.4-93.9 Mb), BTA11 (11:99.2-99.7), and BTA14 (14: 26.1-26.8) related to growth and milk traits also were defined as candidate selection signatures. The selective signals identified in this study reflected the direction of the selection pressure that primarily involves the increase of live weight traits in the Sardo Negro cattle breeding program.
Early in 1995 the first case of Hantavirus Pulmonary Syndrome was serologically confirmed in El Bolsón (Province of Río Negro, Argentina), corresponding to the third outbreak reported in Argentina. A total of 26 cases of HPS related to the Andean region of Rio Negro Province, were reported from 1993 to 1996, 17 in El Bolsón, 4 in San Carlos de Bariloche, and 5 in Buenos Aires. The incidence rate was 5.03 x 100,000 with a mortality rate of 51.85 x 100. The occurrence of cases was mainly seasonal, with a significantly greater number in the spring, and the persons affected mainly lived in urban or periurban areas. In four cases, the affected individuals were members of a couple, spouses or live-in contacts. Seven cases were Health workers (physicians, nurses or administrative staff). Twelve cases were related among them, due to an outbreak of 80 days. Two of them did not visit the Andean region. A total of 139 rodents were captured and seven of them, Olygoryzomys longicaudatus, were found to be serologically positive. The possibility of infection by contact with rodents or fecal matter is being analyzed and also hypothesis related with interhuman transmission.
We report three new autochthonous cases of chronic chagasic cardiomyopathy from Rio Negro, Amazon State, confirmed by serology (indirect immunofluorescence, ELISA and Western-blot for Trypanosoma cruzi infection), clinical examination, chest X-rays, electro- and echocardiography. The three patients were born and lived all their lives in the Rio Negro region working as piaçaba gatherers, where they were bitten several times by sylvatic triatomine bugs. The clinical feature was congestive heart failure and intraventricular conduction impairment in the three cases (right bundle branch block with left anterior hemiblock in two cases, left bundle branch block of 3rd degree in one), polymorphic ventricular extrasystoles in two cases and primary T wave inversion in another one. The echocardiographic evaluation showed a significant increasing of the left ventricular diameters with ejection fraction lesser than 36%, and myocardial segmental impairment pattern, including apical aneurysm and postero-inferior akinesia in the three patients. These are the first autochthonous cases of chronic Chagasic cardiomyopathy from the Brazilian Amazon state with echocardiographic pattern suggestive of Chagas' disease.
The aim of this study was to investigate the effect on an increase of temperature on the net ion fluxes on Metynnis hypsauchen, a teleost species from the Rio Negro. Fish were collected in the Anavilhanas archipelago, Rio Negro, Amazon. After 24 h adaptation fish were placed in individual chambers served with a steady flow of recirculated water. Na+ and Cl- fluxes were determined at 26 and 33 degrees C. After 18 h in the chambers, fish presented an influx of Na+ and Cl-, and the temperature raise to 33 degrees C led to an efflux of both ions, which remained even after 6 h in this temperature. Six hours were not enough to promote a significant reduction of net ion effluxes, but certainly the fluxes would be in net balance after a longer period of time, since this species can be exposed to this temperature in its natural environment.
PURPOSE: This study was carried out in Monte Negro (state of Rondônia), a village in the Brazilian western Amazon region, where a University of São Paulo Medical School program for medical student training in rural assistance took place. It aimed to determine the prevalence of hepatitis B virus and hepatitis C virus, to investigate risk factors for infection, and to evaluate the State immunization program against hepatitis B virus in the region. METHODS: The study is a cross-sectional seroprevalence survey, comprising 267 volunteers who answered a comprehensive questionnaire and had blood samples collected, which were analyzed in São Paulo for the presence of antibodies against hepatitis B virus (Hbs Ag, anti-Hbs, and anti-Hbc) and hepatitis C virus using commercial kits. Data were stored in a specific data bank, and the association between seropositivity and potential risk factors was analyzed by means of uni-, bi-, and multi-variate analysis, considering +/- 5%. RESULTS: The seroprevalence of hepatitis B virus was 61.79% and of hepatitis C virus was 0.38%. Statistical analysis on the data bank showed that the prevalence of hepatitis B virus rose significantly with age, especially after adolescence. Infection was higher in those coming from outside the state of Rondônia. Exposure to vaccination against hepatitis B virus was higher in younger individuals and in those who were born in Rondônia. CONCLUSION: Monte Negro is a highly endemic region for hepatitis B virus but not for hepatitis C virus. Our results also provide indirect evidence indicating a significant improvement in the immunization program in Rondônia in recent years.
A study of two hundred and fifty secondary school children (125 males and 125 females) in Ibadan metropolis was done, to determine mean tooth sizes for the population. The data obtained in Nigerians were then compared with a similar data obtained in American Negros by Richardson and Malhotra (1975). This was done on computer using the Student T-test and taking a probability value greater than 1% (P>0.01) as not significant. The results showed that there was no significant difference in tooth sizes of Nigerians and American Negroes. This could be genetically linked, signifying that Black Americans may have originated from Africa.
The prevalence of osteo-arthrosis of the hip, the knee, the small joints of the hand and the metatarsophalangeal joint of the big toe, has been studied in a South African Negro population. The pattern of joint involvement differed considerably from that expected in a White population. Interphalangeal osteo-arthrosis was much less common in Black women than in White, and Heberden's nodes were seen in only 3 of 93 respondents who were over 65 years of age. Osteo-arthrosis of the metacarpophalangeal joints also, was less common in Black women than in White, but the Black men showed a much greater involvement than that seen in White men. As in White peoples, osteo-arthrosis of the metatarsophalangeal joint of the big toe was commoner in women than in men, but the over-all prevalence did not reach the high levels in Whites. Osteo-arthrosis of the knee was much commoner in the women than in the men; this was associated with a marked tendency to obesity in the older women. The hip joint which is a common site for osteo-arthrosis in Whites, was seldom affected in this Black population. It is clear from this study that the apparent rarity of certain forms of degenerative arthritis in the South African Negro is not owing to any inherent resistance to the disease, because osteo-arthrosis of certain joints, such as the knee in women and the metacarpophalangeal joints in men, is even more common in Blacks than in Whites. The differences encountered can, in many instances, be attributed to differences in occupation and life style in the two populations; but genetic factors, may also play a part in the sense that certain predisposing disorders, such as congenital subluxation of the hip, appear to be far less common in Blacks than in Whites.
Two fatal cases of human chronic chagasic cardiomyopathy are reported, for the first time, in autochthonous patients from Rio Negro, Amazonas state. Both cases, (45 year old man and 44 year old woman) who were born and lived their whole lives in the Rio Negro region, in the northern part of the state of Amazonas, reported having been bitten several times by triatomine bugs in their camping huts while gathering pia ava fibers. The patients, who had confirmed positive serology for Trypanosoma cruzi antibodies (indirect immunofluorescence, ELISA and Western blot), developed in the last 5-7 years a progressive cardiac failure, with global enlargement of the heart, atrioventricular and left bundle branch block, ventricular extrasystoles, both dying from irreversible cardiac insufficiency. The histopathology of a post-mortem surgical cardiac biopsy performed in one of the cases showed chronic myocarditis with diffuse mononuclear cell infiltrates, with areas of focal cell accumulation, fibrosis, lytic necrosis of myocardial fibers, suggestive of chronic chagasic myocarditis. An in situ PCR was positive for Trypanosoma cruzi.
OBJECTIVE: To determine whether the increase in the percentage of stunted growth in Bush Negro infants in the interior of Surinam is related to an absolute food (i.e. energy) shortage or to a shortage of protein. DESIGN: Descriptive. METHOD: In the villages of Dan and Botopasi, children aged 2-5 years from two schools and their mothers were examined. Growth during the first year of life, duration of breastfeeding, age of introduction of and composition of complementary feeding and current nutritional status of mother and child were determined. RESULTS: Sixteen children and their mothers were included. Compared to the Dutch growth charts, birth weight was significantly lower (p = 0.03). After the age of 6 months there was a significant dropping off in weight gain (p = 0.018). Five of the 16 children received protein-poor complementary feeding, which did not lead to catch-up growth. Between the ages of 2-5, 6 of the 16 children showed stunted growth but none of the children or their mothers was wasted. Five of the 16 mothers had a body mass index > 25. CONCLUSION: The nutritional status of the mothers showed that there was no absolute shortage of energy. The protein content coming from the complementary food for the Bush Negroes in our research group was below recommended levels. Stunted growth in these children is better explained by a shortage of well-balanced complementary feeding rather than by an absolute shortage of energy. Education about food recommendations for the young child is of great importance in the prevention of chronic malnutrition.