Differences in prevalence of hepatitis B virus infection and genotypes between ethnic populations in Suriname, South America.

Epidemiological data on hepatitis B virus (HBV) are needed to benchmark HBV elimination goals. We recently assessed prevalence of HBV infection and determinants in participants attending the Emergency Department in Paramaribo, Suriname, South America. Overall, 24.5% (95%CI = 22.7-26.4%) of participants had anti-Hepatitis B core antibodies, which was associated with older age (per year, adjusted Odds Ratio [aOR] = 1.03, 95%CI = 1.02-1.04), Afro-Surinamese (aOR = 1.84, 95%CI = 1.52-2.19) and Javanese ethnicity (aOR = 1.63, 95%CI = 1.28-2.07, compared to the grand mean). 3.2% of participants were Hepatitis B surface Ag-positive, which was also associated with older age (per year, aOR = 1.02, 95%CI = 1.00-1.04), Javanese (aOR = 4.3, 95%CI = 2.66-6.95) and Afro-Surinamese ethnicity (aOR = 2.36, 95%CI = 1.51-3.71). Sex, nosocomial or culturally-related HBV transmission risk-factors were not associated with infection. Phylogenetic analysis revealed strong ethnic clustering: Indonesian subgenotype HBV/B3 among Javanese and African subgenotypes HBV/A1, HBV/QS-A3 and HBV/E among Afro-Surinamese. Testing for HBV during adulthood should be considered for individuals living in Suriname, specifically with Javanese and Afro-Surinamese ancestry.

Vertebral body bone strength: the contribution of individual trabecular element morphology.

SUMMARY: Although the amount of bone explains the largest amount of variability in bone strength, there is still a significant proportion unaccounted for. The morphology of individual bone trabeculae explains a further proportion of the variability in bone strength and bone elements that contribute to bone strength depending on the direction of loading. INTRODUCTION: Micro-CT imaging enables measurement of bone microarchitecture and subsequently mechanical strength of the same sample. It is possible using micro-CT data to perform morphometric analysis on individual rod and plate bone trabeculae using a volumetric spatial decomposition algorithm and hence determine their contribution to bone strength. METHODS: Twelve pairs of vertebral bodies (T12/L1 or L4/L5) were harvested from human cadavers, and bone cubes (10 × 10 × 10 mm) were obtained. After micro-CT imaging, a volumetric spatial decomposition algorithm was applied, and measures of individual trabecular elements were obtained. Bone strength was measured in compression, where one bone specimen from each vertebral segment was tested supero-inferiorly (SI) and the paired specimen was tested antero-posteriorly (AP). RESULTS: Bone volume fraction was the strongest individual determinant of SI strength (r(2) = 0.77, p < 0.0001) and AP (r(2) = 0.54, p < 0.0001). The determination of SI strength was improved to r(2) = 0.87 with the addition of mean rod length and relative plate bone volume fraction. The determination of AP strength was improved to r(2) = 0.85 with the addition of mean rod volume and relative rod bone volume fraction. CONCLUSIONS: Microarchitectural measures of individual trabeculae that contribute to bone strength have been identified. In addition to the contribution of BV/TV, trabecular rod morphology increased the determination of AP strength by 57%, whereas measures of trabecular plate and rod morphology increased determination of SI strength by 13%. Decomposing vertebral body bone architecture into its constituent morphological elements shows that trabecular element morphology has specific functional roles to assist in maintaining skeletal integrity.

Beta S haplotypes in various world populations.

We have determined the beta S haplotypes in 709 patients with sickle cell anemia, 30 with SC disease, 91 with S-beta-thalassemia, and in 322 Hb S heterozygotes from different countries. The methodology concerned the detection of mutations in the promoter sequences of the G gamma- and A gamma-globin genes through dot blot analysis of amplified DNA with 32P-labeled probes, and an analysis of isolated Hb F by reversed phase high performance liquid chromatography to detect the presence of the A gamma T chain [A gamma 75(E19)Ile----Thr] that is characteristic for haplotype 17 (Cameroon). The results support previously published data obtained with conventional methodology that indicates that the beta S gene arose separately in different locations. The present methodology has the advantage of being relatively inexpensive and fast, allowing the collection of a vast body of data in a short period of time. It also offers the opportunity of identifying unusual beta S haplotypes that may be associated with a milder expression of the disease. The numerous blood samples obtained from many SS patients living in different countries made it possible to compare their hematological data. Such information is included (as average values) for 395 SS patients with haplotype 19/19, for 2 with haplotype 17/17, for 50 with haplotype 20/20, for 2 with haplotype 3/3, and for 37 with haplotype 31/31. Some information on haplotype characteristics of normal beta A chromosomes is also presented.

The usefulness of sequence analysis of amplified DNA for the identification of delta chain variants.

A method of identifying delta chain variants using relatively small volumes of blood is described. The procedure consists of the amplification of two segments of genomic DNA with two sets of delta chain specific primers and sequencing of the three exons (exons 1, 2, and 3) which are part of the amplified DNA segments. Data for three delta chain variants present in seven adult heterozygotes are presented.

Observations on the levels of Hb A2 in patients with different beta-thalassemia mutations and a delta chain variant.

Hb A2 and its variant B2 (alpha 2 delta 2(16)(A13)Gly----Arg) were quantitated in the blood of subjects with three different types of beta-thalassemia and with the delta-B2 anomaly in cis or in trans to the beta-thalassemia determinant. In one family, the delta-B2 mutation was in cis to a newly discovered codon 47 (+A) frameshift. The levels of Hbs A2 and B2 were nearly the same and approximately 70% higher than those in simple Hb B2 heterozygotes. In two additional families, the delta-B2 variant was in trans to either a deletional beta-thalassemia (1,393 bp) involving part of the beta-globin gene and part of the beta-globin gene promoter, or to the -88 C----T promoter mutation. In both instances, the Hb B2 level was increased by approximately 80%, but the Hb A2 level was increased by approximately 270% and 200%, respectively. These data indicate two mechanisms that will cause an increase in delta chain production. One is consistent with a general mechanism concerning the relative excess of alpha chains in beta chain deficiencies which will combine with delta chains to form variable levels of Hb A2 dependent on the severity of the beta chain deficiency. The second concerns the loss of beta-globin gene promoter activity, perhaps by an absence of (or decreased) binding of specific protein(s) to this segment of DNA and a concomitant increase in delta-globin gene promoter activity in cis.

Hb Icaria-Hb H disease: identification of the Hb Icaria mutation through analysis of amplified DNA.

Hb Icaria-Hb H disease was observed in a Yugoslavian teenager who exhibited moderate anaemia with severe microcytosis and hypochromia and 16% Hb H. Four of his relatives were Hb Icaria heterozygotes; their haematological data were comparable to those with a deletional type of alpha-thalassaemia-2. The patient also had an additional alpha-thalassaemia-1 deletion, an approximately 20.5 kb deletion, common among Mediterranean populations. The Hb Icaria mutation, i.e. the TAA----AAA mutation at codon 142, was identified by hybridization of amplified DNA with specific probes. The mutation is located on the alpha 2-globin gene; the one remaining alpha 1-globin gene is apparently able to compensate sufficiently for the loss of the three alpha-globin genes to maintain a haemoglobin level of 8-9 g/dl.

Hemoglobin Birmingham and hemoglobin Galicia: two unstable beta chain variants characterized by small deletions and insertions.

Two unstable hemoglobins (Hbs) causing rather severe hemolytic anemia have been characterized. The beta chain of Hb Birmingham, found in an adult black man, is characterized by the loss of -Leu-Ala-His-Lys- at positions 141, 142, 143, and 144 and their replacement by one Gln residue. These changes are the result of a deletion of nine nucleotides, namely two base pairs (bp) of codon 141, all of codons 142 and 143, and one bp of codon 144; the remaining CAG triplet (C from codon 141 and AG from codon 144) codes for the inserted glutamine. In the beta chain of Hb Galicia from a Spanish patient, His and Val at positions 97 and 98 are replaced by one Leu residue. This is due to an ACG deletion in codons 97 and 98, which causes the removal of one His and one Val residue, while the remaining CTG triplet (C from codon 97 and TG from codon 98) codes for the inserted leucine residue. Two mechanisms, namely slipped mispairing in the presence of short repeats, and misreading by DNA polymerase due to a local distortion of the DNA helix, are considered in explaining the origin of the small deletions.

Compound heterozygosity for a mild beta (+) and a rare beta(0)-thalassemia allele.

Hematological and hemoglobin composition data are presented for 14 members of a Surinam family (and for 1 unrelated subject) with either a beta-thalassemia heterozygosity [5 with the -29 (A----G) beta + mutation and 5 with the IVS II-849 (A----G) beta(0) mutation] or a compound heterozygosity (the 5 remaining patients). Identification of the mutation was by hybridization of amplified DNA with 32P-labelled synthetic oligonucleotides. The data indicate distinct differences between the two groups of heterozygotes, mainly in degree of microcytosis and hypochromia, in Hb A2 level, and in the level of G gamma (high in the -29 heterozygotes and low in the IVS II-849 heterozygotes). The 5 compound heterozygotes had a thalassemia intermedia with high Hb F levels (high G gamma), elevated Hb A2, and Hb A levels comparable to those seen in patients with a homozygosity for the -29 mutation or with the combination of this beta(+)-thalassemia and Hb S. An alpha-thalassemia-2 heterozygosity (-3.7 kb deletion) was present in 2 patients. Their hematological data were improved over those for the patients with four alpha globin genes; one was the mother of two sets of twins. The high G gamma value in the Hb F of the compound heterozygotes suggests that the high Hb F production in the condition is mainly directed by the chromosome with the -29 (A----G) mutation.

Hb Sun Prairie or alpha(2)130(H13)Ala----Pro beta 2, a new unstable variant occurring in low quantities.

A severe hemolytic anemia with microcytosis and hypochromia was present in a young adopted Indian patient. Reversed phase high performance liquid chromatographic methodology and heat stability tests detected an unstable alpha chain which was present in 3 to 5% of the total hemoglobin. A larger quantity of the alpha X chain was obtained by preparative reversed phase high performance liquid chromatography. Structural analyses identified an Ala----Pro replacement at position 130 of the alpha chain. The instability of the variant, named Hb Sun Prairie, is comparable to that of Hb Bibba [alpha 136 (H19)Leu----Pro]. Gene mapping failed to detect an alpha-thalassemia deletion (alpha alpha/alpha alpha), while dot-blot analysis of amplified DNA with synthetic probes localized a G----C mutation in codon 130 (resulting in the Ala----Pro mutation) of the alpha 2-globin genes of both chromosomes. These results suggest a homozygosity for the G----C mutation and the condition alpha 2(G----C)alpha 1/alpha 2(G----C)alpha 1 adequately explains the rather severe clinical status of this child, including the marked microcytosis and hypochromia. Unfortunately, family studies to exclude the presence of a large deletion involving all zeta- and alpha-globin genes were not possible.

Hb A2-Wrens or alpha 2 delta 2 98(FG5) Val----Met, an unstable delta chain variant identified by sequence analysis of amplified DNA.

Data are reported for an 85-year-old black make who had an HPFH condition on one chromosome and a suspected 'delta-thalassemia' on the other. Sequence analysis of amplified DNA of an appropriate segment of the delta-globin gene identified a GTG to ATG mutation for codon 98 and thus a Val----Met replacement in the delta chain. This abnormality was confirmed by hybridization of amplified DNA with 32P-labeled synthetic probes and by the amino-acid composition of the isolated tryptic peptide delta T-11. Thus, the 'delta-thalassemia' is caused by the presence of an Hb A2 variant that is considered to be unstable to a similar extent as is Hb Köln, its beta chain counterpart.

Hb Chad or alpha 223(B4)Glu----Lys beta 2 observed in members of a Surinam family in association with alpha-thalassemia-2 and with Hb S.

Three different hemoglobinopathies, i.e. Hb S, Hb Chad [alpha 23 (B4)Glu----Lys], and alpha-thalassemia-2 (-3.7) have been observed in eight members of a family from Surinam. The proposita had all three abnormalities, while her mother and four of her half-brothers had Hb Chad together with an alpha-thalassemia-2 heterozygosity or homozygosity. Gene mapping and dot-blot analysis of amplified DNA identified a G----A mutation in codon 23 of the alpha 2 alpha 1 hybrid gene resulting in the Glu----Lys substitution. The quantity of the alpha-Chad chain averaged 31.5% in its carriers with an additional alpha-thalassemia-2 heterozygosity [-alpha Chad(-3.7 kb)/alpha alpha], and 43% in the two carriers with an additional alpha-thalassemia-2 homozygosity [-alpha Chad (-3.7 kb)/-alpha (3.7 kb)]. These quantities are considerably higher than those reported for families from Chad, China, and Japan; the low levels of 14.5-24% Hb Chad in members of previously reported cases suggest a mutation on a chromosome with two alpha-globin genes [alpha alpha Chad/alpha alpha or alpha Chad alpha/alpha alpha].

Screening urine specimen populations for normality using different dipsticks: evaluation of parameters influencing sensitivity and specificity.

The reagent test strip Combur-9 Test-RL (Boehringer Mannheim) and the 8-SG Multistix (Ames) were simultaneously evaluated as a rapid method for screening urines for normality. Differences between the two methods are for a considerable part determined by adjustment of the lowest detection limits of the leukocyte and erythrocyte dipstick fields. Patient populations (243 specimens presented to the routine laboratory and 230 specimens submitted for microbiological culture), sediment analysis (routine or standardized) and composition of the screening protocol strongly influence values obtained for the sensitivity, specificity and predictive values, whereas use of a different dipstick is of minor importance on the final results. Higher sensitivity and specificity are observed when relating positive dipstick screening to positive culture than when relating positive standardized sediment to positive culture. Evaluation of dipstick method, using microscopic sediment analysis as a reference parameter appears to be very dependent on the quality of the latter, which is therefore relatively unsuitable for this purpose. Apart from standardization, additional clinically significant findings are obtained using dipstick screening.