[Glycemia and glycorrhachia compared in the healthy Negro and in the Negro with trypanosomiasis].
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Black People↗
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Drinking among Negroes. Inferences from the drinking patterns of selected Negro male collegians.
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Adolescent↗
Effects of water pH and calcium concentration on ion balance in fish of the Rio Negro, Amazon.
We examined the effects of acute low-pH exposure on ion balance (Na+, Cl-, K+) in several species of fish captured from the Rio Negro, a dilute, acidic tributary of the Amazon. At pH 5.5 (untreated Rio Negro water), the four Rio Negro species tested (piranha preta, Serrasalmus rhombeus; piranha branca, Serrasalmus cf. holandi; aracu, Leporinus fasciatus; and pacu, Myleus sp.) were at or near ion balance; upon exposure to pH 3.5, while Na+ and Cl- loss rates became significant, they were relatively mild. In comparison, tambaqui (Colossoma macropomum), which were obtained from aquaculture and held and tested under the same conditions as the other fish, had loss rates seven times higher than all the Rio Negro species. At pH 3.0, rates of Na+ and Cl- loss for the Rio Negro fish increased three- to fivefold but were again much less than those observed in tambaqui. Raising water Ca2+ concentration from 10 micromol L-1 to 100 micromol L-1 during exposure to the same low pH's had no effect on rates of ion loss in the three species tested (piranha preta, piranha branca, aracu), which suggests that either they have such a high branchial affinity for Ca2+ that all sites are saturated at 10 micromol L-1 and additional Ca2+ had no effect, or that Ca2+ may not be involved in regulation of branchial ion permeability. For a final Rio Negro species, the cardinal tetra (Paracheirodon axelrodi), we monitored body Na+ concentration during 5 d of exposure to pH 6.0, 4.0, or 3.5. These pH's had no effect on body Na+ concentration. These data together suggest that exceptional acid tolerance is a general characteristic of fish that inhabit the dilute acidic Rio Negro and raise questions about the role of Ca2+ in regulation of branchial ion permeability in these fish.
Acid-Base Equilibrium↗
A cephalometric evaluation of American Negro women.
A cephalometric study of forty American Negro women with an average age of 24.6 years and a Class I molar and/or canine relationship was performed. When measurements were compared to a control population of twenty Caucasian women, using several standard analyses, significant differences were demonstrated between the sample populations. 1. The maxilla and mandible were more protrusive in the Negro sample. 2. The upper and lower incisors were more proclined and the interincisal angle was more acute in the Negro sample. 3. Middle facial height was shorter and lower facial height was longer in the Negro sample. 4. The projection of the soft-tissue nasal tip was less in the Negro sample. 5. The projection of the upper and lower lips as related to the facial plane was greater in the Negro sample. 6. Lip thickness was approximately the same in the two groups.
Adult↗
The craniofacial skeletal pattern of the South African Negro.
Lateral cephalometric head film measurements on twenty-seven male and twenty-eight female adult craniums and mandibles with excellent occlusions were compared with similar measurements on Caucasoids with excellent occlusions. Among the differences between the two groups is the forward position of the short maxilla relative to the anterior cranial base in the South African Negro. The forward location of point A has the effect of increasing the ANB angle, since the relative position of point B in both groups is much the same. Unlike the American Negro, the labial inclination of the upper incisors in the South African Negro is not pronounced but is similar to the inclination observed in Caucasoids. Because of the large ANB angle, the lower incisors in the S.A. Negro (as in the American Negro) are severely labially inclined. Ramus height in the S.A. Negro is shorter than that of Caucasoids and appears to be related to the steep mandibular plane observed in the former population group.
Black People↗
Hodgkin's disease in American Negroes. Histologic classification of the disease in 143 untreated patients, and age distribution.
The Rye histologic classification of Hodgkin's disease has been applied to 143 previously untreated cases of Hodgkin's disease in Negro patients seen in four hospitals in Washington, D.C.,during a 16-year period (1959-1974). The frequencies and age distributions of histologic subtypes were compared with those in American and two African series. Those histologic subtypes associated with poor prognoses (mixed-cellularity and lymphocytic depletion) predominated in American Negroes and in Negroes from Ibadan, Nigeria, and Kampala, Uganda. In an American series from Connecticut (approximately 98% Caucasian) the histologic subtypes lymphocytic predominance and nodular sclerosis were preponderant. There were statistically significantly less of the nodular sclerosis subtype (P less than 0.005), and more of the mixed-cellularity subtype in American Negroes compared with the Connecticut series (P less than 0.001). In contrast to findings in predominantly Caucasian populations, there was a predilection of the nodular sclerosis subtype for males in American and in African Negroes. This study showed that Hodgkin's disease in American Negroes epidemiologically corresponds to the so-called "intermediate pattern" of the disease.
Adolescent↗
Three examples of anti-Fy3 produced in Negroes.
We present three examples of anti-Fy3 produced by Negroes. Results of serologic studies were similar to those of previously reported examples of Negro produced anti-Fy3, including negative to weak reactivity with cord red blood cells, separable anti-Fya, and the presence of multiple unexpected alloantibodies. These findings reinforce the difference between anti-Fy3 produced by Negroes and that produced by non-Negroes. The rare formation of Duffy antibodies by Negroes may signify the presence of an amorphic gene at the Duffy locus.
Adult↗
Genetic markers and leprosy in South African negroes: Part II. Erythrocyte enzyme polymorphisms.
The phenotype frequencies of the erythrocyte enzyme polymorphisms acid phosphatase (aP), phosphoglucomutase loci 1 and 2 (PGM1 and PGM2), adenylate kinase (AK), adenosine desaminase (ADA), esterase D (EsD) and 6-phosphogluconate dehydrogenase (6-PGD) were determined on a sample of 234-248 South African Negroes with leprosy. These results were compared with data of 841--997 healthy Negro controls of similar geographical and ethnic origin, in order to determine whether or not any association exists between specific phenotypes and the manifestation of leprosy. A part of the data included in the present study were compared with the data of a similar comparative analysis on Mozambican Negroes. With regard to the polymorphisms aP, PGM1 and PGM2, the results derived from South Africa and Mozambique exhibit reverse patterns of deviations from the null hypothesis. From this it does not appear justified to postulate an association between these genetic markers and the occurrence of leprosy. For the enzyme polymorphisms ADA, AK and EsD (data are confined to South African Negroes only) the distribution of phenotypes between patients and controls was very similar. The differences were not statistically significant. However, observations on the 6-PGD polymorphism (data are confined to South African Negroes only) showed an excess of phenotype PGD A among leprosy patients as compared with controls. The difference was statistically highly significant. Further studies based on additional samples are required to substantiate whether or not the statistical outcome reflects a true association between this phenotype and leprosy.
Acid Phosphatase↗
The plasminogen polymorphism in South African Negro populations: genetics and anthropogenetics.
Genetic polymorphism of human plasminogen (PLG) was investigated in 1252 unrelated individuals from eight South African Bantu-speaking Negro tribes. PLG phenotypes were determined by isoelectric focusing (pH 3.5-9.5 and 5-8 gradients) of neuraminidase-treated samples and subsequent detection by caseinolytic overlay or immunoblotting with specific antibody. No significant difference in the distribution of PLG alleles among the eight ethnic groups was observed. The combined allele frequencies of the common alleles in South African Negroes were 0.6977 for PLG*A, 0.2736 for PLG*B. In addition, six rare alleles were seen: PLG*A3, *A1, *M2, *B1, *B2, *B3. The rare variant PLG*B2 was proven to segregate by autosomal Mendelian inheritance in a family. The combined frequency for the rare alleles was 0.0287. The distribution of phenotypes in the total population sample was found to be in Hardy-Weinberg equilibrium. A striking difference in PLG allele distribution between Negroes from South Africa and published Negroid frequencies from North America could be observed. This difference was also seen in comparison with Mongoloid populations; in contrast, PLG frequencies for South African Negroes were similar or almost identical to known Caucasoid distributions.
Alleles↗
An epidemiologic survey of malocclusions among American Negroes and American Hispanics.
The malocclusions of thirty-six Negro and fifty-six Puerto Rican orthodontic patients from a specific area were surveyed. The population was divided according to sex, age, and skeletal classification. The total Negro malocclusion sample was compared to available Negro norms for both Downs and Steiner analyses. The total Hispanic malocclusion group was compared to available Negro and Caucasian norms for the same analyses. Ranges, means, and standard deviations were developed for each measurement recorded. The comparative frequency of individual skeletal classifications was found to be remarkably similar in both groups, and the percentage of open-bites was greater in both groups than in the general population. The need to expand available material to include a Puerto Rican group is noted.
Adolescent↗
Cephalometric standards for American Negro children.
1. Our findings are comparable to the measurements of Drummond and Altemus. 2. Most skeletal measurements of the Alabama Negro are greater than those of Caucasians. 3. There is no difference between Caucasians and Negroes in the mean of the facial plane--SN angle. 4. The maxilla is proportionately more anteriorly placed than the mandible in the Negro. 5. The upper and lower incisors are more procumbent and protrusive in Negroes. 6. Standard deviations are about the same for whites and blacks, other than those for skeletal measurements. 7. Neither Angle's Class II nor Class III malocclusions occur as frequently in the black population as in the white population.
Adolescent↗
A study of the HLA-Dw determinants and their relationship to DR and DQ antigens in three South African population groups: South African Caucasoids, South African Negroes, and Cape coloureds.
The HLA-Dw specificities of a group of 177 unrelated randomly selected healthy individuals consisting of 67 South African Negroes (Xhosa), 57 Cape Coloureds, and 53 South African Caucasoids were determined. HLA-Dw specificities were determined in a mixed lymphocyte culture test using HTCs. Antigen and gene frequencies as well as the association between HLA-DR, DQ, and Dw were established in three populations. HLA-Dw gene frequencies in the South African Caucasoids agreed with these frequencies in other Caucasoid groups. The HLA-Dw1 frequency was decreased in the Cape Coloureds and South African Negroes compared to the Caucasoids. The gene frequency of Dw3 was low in the South African Negroes in spite of the fact that DR3 is a common DR antigen in this group. A high frequency of Dw 'blank' was observed in the South African Negroes and Cape Coloureds, suggesting the existence of undefined HLA-Dw specificities in these populations. Data concerning the HLA-Dw, DR, and DQ relationships showed that once a certain Dw specificity was associated with a particular DR and DQ antigen, this association remained a fixed entity in the different population groups.
Black People↗
Negro alpha-thalassaemia is caused by deletion of a single alpha-globin gene.
Studies in two Jamaican Negro families, including haematological and haemoglobin analysis, haemoglobin synthesis, and globin messenger-RNA assay, have defined two alpha-thalassaemia phenotypes which resemble the severe (alpha-thalassaemia 1) and mild (alpha-thalassaemia 2) forms of the disorder described in Orientals. Genetic analysis suggests that subjects with the alpha-thalassaemia-1 phenotype are homozygous for the alpha-thalassaemia-2 determinant. Restriction-endonuclease mapping shows that alpha-thalassaemia-2 results from the deletion of one of the linked pair of alpha-chain genes. Hence the genotypes of the alpha-thalassaemia heterozygotes and homozygotes in these families are -alpha/alpha alpha and -alpha/-alpha respectively. If these are the usual alpha-thalassaemia genotypes in Negroes, these findings explain the difference in clinical expression of the disorder between Orientals and Negroes--in particular, the absence of haemoglobin Bart's hydrops and the rarity of haemoglobin-H disease in Negroes.
Black People↗
Lower frequency of diabetes among hospitalized Negro than white children: theoretical implications.
A review of the case histories of 471 diabetic children admitted to a children's hospital during the decade 1960 to 1970 showed that the proportion of diabetics among hospitalized Negro children was significantly lower than that among white children (3.8 Negro vs. 10.7 white per 1000 admissions same ethnic group, P less than 0.005). However, the proportion of mild diabetes, characterized by absence of ketosis and no insulin requirement, was higher among Negro (18%) than among white diabetic children (0.5%). These differences could not be explained by differences in environmental factors considered. It is suggested that genetic factors may account for a substantial part of this Negro-white difference.
Adolescent↗
Evidence for a secular trend in the Negro dentition.
Metric changes in the Negro dentition were evaluated in a sample of artificial stone casts of the dental arcades of 106 living South African Negroes (56 males, 50 females) and in 100 Negro crania (50 males, 50 females) drawn from the R. A. Dart Collection. Comparison of the mesiodistal and buccolingual dimensions of these two samples to the published results of a similar study on earlier Negroes revealed a statistically significant trend towards tooth-size enlargement. This positive secular trend was found to be most pronounced in the mesiodistal diameter, with less than half of the teeth considered showing significant buccolingual enlargement. Although the trend was equally pronounced in both sexes and in both arcades, mesiodistal change was found to increase in an antero-posterior direction, while buccolingual change centred around the anterior teeth.
Black People↗
Diverse strategies for ion regulation in fish collected from the ion-poor, acidic Rio Negro.
We measured unidirectional ion fluxes of fish collected directly from the Rio Negro, an extremely dilute, acidic blackwater tributary of the Amazon. Kinetic analysis of Na(+) uptake revealed that most species had fairly similar J(max) values, ranging from 1,150 to 1,750 nmol g(-1) h(-1), while K(m) values varied to a greater extent. Three species had K(m) values <33 micromol L(-1), while the rest had K(m) values >or=110 micromol L(-1). Because of the extremely low Na(+) concentration of Rio Negro water, the differences in K(m) values yield very different rates of Na(+) uptake. However, regardless of the rate of Na(+) uptake, measurements of Na(+) efflux show that Na(+) balance was maintained at very low Na(+) levels (<50 micromol L(-1)) by most species. Unlike other species with high K(m) values, the catfish Corydoras julii maintained high rates of Na(+) uptake in dilute waters by having a J(max) value at least 100% higher than the other species. Corydoras julii also demonstrated the ability to modulate kinetic parameters in response to changes in water chemistry. After 2 wk in 2 mmol L(-1) NaCl, J(max) fell >50%, and K(m) dropped about 70%. The unusual acclimatory drop in K(m) may represent a mechanism to ensure high rates of Na(+) uptake on return to dilute water. As well as being tolerant of extremely dilute waters, Rio Negro fish generally were fairly tolerant of low pH. Still, there were significant differences in sensitivity to pH among the species on the basis of degree of stimulation of Na(+) efflux at low pH. There were also differences in sensitivity to low pH of Na(+) uptake, and two species maintained significant rates of uptake even at pH 3.5. When fish were exposed to low pH in Rio Negro water instead of deionized water (with the same concentrations of major ions), the effects of low pH were reduced. This suggests that high concentrations of dissolved organic molecules in the water, which give it its dark tea color, may interact with the branchial epithelium in some protective manner.
Adaptation, Physiological↗
HLA-A, B, C, DR and DQ polymorphisms in three South African population groups: South African Negroes, Cape Coloureds and South African Caucasoids.
The HLA class I and II phenotypes of the three population groups in the Cape Province of South Africa were determined. The HLA-A,B, and C antigens were tested in 1027 South African Negroes (Xhosa), 3716 Cape Coloureds and 1059 South African Caucasoids. This is the first study which has also included the class II antigens in the Southern African Negroes (Xhosa). The numbers tested for the DR and DQ antigens were smaller, as only typings done after the 8th Histocompatibility Workshop were included. A comparison was made between the frequencies in the Xhosa, the Cape Coloureds and the South African Caucasoids as well as the Nigerians, another group who also belong to the Bantu-speaking division of African Negroes and who were recently studied. The antigen, gene and haplotype frequencies were estimated in all three groups, and the genetic distances calculated. Striking differences in gene and haplotype frequencies between the various populations were seen. For example, Bw42 had a phenotype frequency of 0.062 in the Cape Coloureds, 0.213 in the Xhosa and 0.004 in the South African Caucasoids. The Xhosa showed marked differences in HLA distribution compared to the other Negro group (Nigerians), which can be attributed to a Khoisan admixture, e.g. HLA-DR4 had a phenotype frequency of 0.134 in the Xhosa and only 0.010 in the Nigerians. The haplotype B8,DR3, seen in association with many autoimmune diseases, had a significant delta value in all three populations.
Black People↗
Comparison of IgM and IgG anti-A and anti-B levels in Asian, Caucasian and Negro donors in the North West Thames Region.
This study was undertaken to test the widely held belief that higher levels of immune anti-A and anti-B are characteristic of Negro and Asian populations with a corresponding increased risk factor for AB0 haemolytic disease of the newborn. Overall, 300 serum samples from male and female Asian. Caucasian and Negro blood donors in the North West Thames Region of groups A, B and 0 were collected. The sera were titrated in microplates against pooled group A1 and pooled group B red blood cells. Although the results show that the highest levels for IgG anti-A and anti-B were found in group 0 female Negro donors, statistically these levels are not significantly higher than those of the other group 0 donors tested. We suggest that the potent anti-A and anti-B reported by others in Negro and Asian populations may arise from environmental rather than genetic factors.
ABO Blood-Group System↗