alpha-thalassemia in Bantu population from Congo-Brazzaville: its interaction with sickle cell anemia

Deletional alpha(+)-thalassemia (-alpha(3.7)) was investigated in four groups of unrelated individuals from the Bantu population (newborns, normal adults, sickle cells trait carriers, sickle cell anemia patients) of Brazzaville, Congo. The frequency of the (-alpha(3.7)) chromosome was similar between newborns (f = 0.40) and adult subjects (f = 0.36), and between sicklers and nonsickler subjects. The frequency of the (-alpha(3.7)) chromosome in sickle cell anemia patients (SS patients) did not change when age was stratified. The hematological characteristics of SS patients with (-alpha/alphaalpha, -alpha/-alpha) and without (alphaalpha/alphaalpha) alpha(+)-thalassemia were similar to those reported in Jamaican and US sickle cell anemia patients. alpha(+)-Thalassemia had an effect on the percentage of hemoglobin S in sickle cell trait carriers. Thus, the high frequency of alpha(+)-thalassemia in the Congolese population presumably results from this disorder having a selective advantage favoring survival. However, the frequency of alpha(+)-thalassemia was not affected by age. Although in this selective tropical environment, alpha(+)-thalassemia as elsewhere markedly affects the hematological characteristics of sickle cell anemia patients, however our data provide no evidence that alpha(+)-thalassemia increases survival of SS patients.     

Extremely high frequencies of alpha-globin gene deletion in Madang and on Kar Kar Island, Papua New Guinea.

Extremely high frequencies of the deletion form of alpha(+)-thalassemia (-alpha/), as studied by the DNA mapping technique, were found in the population of Madang, a coastal province in the north of Papua New Guinea (PNG) and in the population of Kar Kar, an island situated near Madang. Ninety-seven percent of the population tested from Madang and 89% of that from Kar Kar Island were either alpha(+)-thalassemia heterozygotes or homozygotes. By contrast, no examples of the deletion form were detected in the Eastern Highlands of PNG. The haplotype frequencies of alpha(+)-thalassemia (-alpha/) in Madang and Kar Kar Island were found to be 81.33% and 66.67%, respectively. A more detailed analysis of the gene deletion revealed that in both populations 96% were of the 4.2 kilobase (kb) type and 4% were of the 3.7-kb type. Thus, this group is the only example in which the 4.2-kb deletion is predominant over 3.7-kb defect. The presence in high frequencies of alpha(+)-thalassemia in the coastal area of Madang and on the neighboring island, where malaria has long been holoendemic or hyperendemic, and its virtual absence from the nonmalarious highlands of PNG suggest the role of malaria as the selective factor in maintaining alpha(+)-thalassemia. If this selective pressure is still operating, and since alpha(+)-thalassemia has no apparent homozygous disadvantage, the abnormal haplotype (-alpha/) will be in the process of fixation in this population.     

Polymorphisms of alpha-1-acid (orosomucoid), alpha-2-HS-glycoproteins and alpha-1-B among the Parsis of India.

Genetic polymorphisms of plasma alpha 1-acid glycoprotein (oro-somucoid, ORM), alpha 2-HS-glycoprotein (A2HS) and alpha 1-B-glycoprotein (alpha 1B) were studied in a group of Parsis in Bombay, India. The frequencies of ORM1*1, ORM1*2 and ORM1*3 were found to be 0.636, 0.356 and 0.008, respectively. A2HS*1, A2HS*2 and A2HS*3 frequencies were 0.855, 0.135 and 0.010, while the frequencies of A1B*1 and A1B*2 were 0.881 and 0.119, respectively. The phenotype distribution at all three loci was at Hardy-Weinberg equilibrium. The ORM2 locus was monomorphic in the Parsis.     

稽留流产患者血清和绒毛中HIF-1alpha和VEGF表达水平及其相关性分析

目的：探讨缺氧诱导因子-1alpha（HIF-1alpha）和血管内皮生长因子（VEGF）在稽留流产患者血清和绒毛中的表达水平及其相关性 分析。方法：选择2014 年8 月至2015 年8 月我院妇产科76 例稽留流产患者为观察组及行人工流产的60 例正常早产孕妇为对 照组;根据患者稽留流产时间将稽留流产患者分为稽留时间<2 周组（12 例）,2~4周组（33 例）,>4周组（31 例）;采用酶联免疫吸 附（ELISA）和免疫组化SP 法检测并分析患者血清与绒毛中HIF-1琢与VEGF的表达水平。结果：观察组血清中HIF-1alpha与VEGF 表达水平均显著低于对照组,差异有统计学意义（P<0.05）;观察组和对照组绒毛VEGF 和HIF-1-alpha均表达,其中VEGF 主要表达 于滋养层细胞细胞质和细胞间质,HIF-1琢主要表达于滋养层细胞的细胞核与细胞质,且观察组患者绒毛HIF-1-alpha与VEGF 表达水 平均显著低于对照组,差异有统计学意义（P<0.05）;不同稽留时间患者绒毛HIF--alpha与VEGF表达水平间比较,差异均无统计学意 义（P>0.05）观察组患者血清HIF-1alpha与VEGF的表达水平呈现正相关关系（r=0.601;P<0.05）;且绒毛HIF-1琢与VEGF的表达水平 也呈现正相关关系（r=0.401;P<0.05）。结论：HIF-1琢和VEGF在血清和绒毛中的低表达可能是稽留流产的发生的重要原因,临床 上可以通过检测患者血清和绒毛组织中HIF-1琢和VEGF的水平,有针对性的对患者进行监护和治疗,预防稽留流产的发生。     

Types of alpha+ thalassemia in Southeast Asia refugees

We have determined alpha+ deletional thalassemia among 143 Southeast Asia refugees (Cambodians, Laotians, and Vietnameses). Gene frequency of alpha+ deletional thalassemia in Vietnameses (0.035) was found lower than in Cambodians and Laotians (0.11). Bam H1 and Bg1 II analysis indicated that both rightward and leftward thalassemias are encountered, the -alpha 3,7 form is being by far more frequent than the -alpha 4.2 one. Only type I cross-over was found by Apa I digestion on -alpha 3.7 chromosomes. The Rsa I polymorphism, 5' to Z alpha 2 block, is associated with -alpha 3.7 type I haplotype and the site is present in 12 out of 23 chromosomes. All these data suggest at least three origins of alpha+-thalassemia in Cambodia and Laos.     

Mating-type control in Saccharomyces cerevisiae: isolation and characterization of mutants defective in repression by a1-alpha 2.

The alpha 2 protein, the product of the MAT alpha 2 cistron, represses various genes specific to the a mating type (alpha 2 repression), and when combined with the MATa1 gene product, it represses MAT alpha 1 and various haploid-specific genes (a1-alpha 2 repression). One target of a1-alpha 2 repression is RME1, which is a negative regulator of a/alpha-specific genes. We have isolated 13 recessive mutants whose a1-alpha 2 repression is defective but which retain alpha 2 repression in a genetic background of ho MATa HML alpha HMRa sir3 or ho MAT alpha HMRa HMRa sir3. These mutations can be divided into three different classes. One class contains a missense mutation, designated hml alpha 2-102, in the alpha 2 cistron of HML, and another class contains two mat alpha 2-202, in the MAT alpha locus. These three mutants each have an amino acid substitution of tyrosine or acid substitution of tyrosine or phenylalanine for cysteine at the 33rd codon from the translation initiation codon in the alpha 2 cistron of HML alpha or MAT alpha. The remaining 10 mutants make up the third class and form a single complementation group, having mutations designated aar1 (a1-alpha 2 repression), at a gene other than MAT, HML, HMR, RME1, or the four SIR genes. Although a diploid cell homozygous for the aarl and sir3 mutations and for the MATa, HML alpha, and HMRa alleles showed alpha mating type, it could sporulate and gave rise to asci containing four alpha mating-type spores. These facts indicate that the domain for alpha2 repression is separable from that for a1-alpha2 protein interaction or complex formation in the alpha2 protein and that an additional regulation gene, AAR1, is associated with the a1-alpha2 repression of the alpha1 cistron and haploid-specific genes.     

Deletional types of alpha-thalassaemia in central Java.

The frequency of deletional alpha-thalassaemia in a Javanese population sample (n = 103) was investigated at three restriction sites of the alpha-globin gene (BamHI, BglII and RsaI). The overall gene frequency of alpha+ deletional thalassaemia was found to be very low (0.03). Leftward (-alpha 4.2) and rightward (-alpha 3.7) deletions and triplicated genes were present in equal frequency (0.015 and 0.005, respectively).     

中国人α珠蛋白基因-α3.7缺失亚型的研究

-α3.7是中国人常见的缺失型α-地中海贫血-2。根据重组位点的不同,-α3.7可分为-α3.7Ⅰ型、-α3.7Ⅱ型和-α3.7Ⅲ型,并且亚型的种类和频率具有种族差异性。本研究在中国人群中用PCR基因分析方法检出具有α珠蛋白基因-α3.7缺失的患者56例,然后用ApalⅠ和BalⅠ限制性内切酶进行分型。 结果表明,在这56例具有-α3.7缺失的患者中,有54例是-α3.7Ⅰ型,有2例是-α3.7Ⅱ型,尚未发现-α3.7Ⅲ型。此结果丰富了我国α地贫基因型谱的资料。 Abstract:-α3.7 is a common deletional α-thalassemia-2 in China.According to different recombination sites,-α3.7 can be divided into -α3.7Ⅰ、-α3.7Ⅱand -α3.7Ⅲ.The frequency and population distribution of these -α3.7 are quite different.In this study,we detected 56 patients among Chinese population of -α3.7 defect in alpha globin gene by PCR method,then the PCR product was digested by the restriction enzyme ApalⅠand BalⅠ.The sub-typing result shows that in the 56 cases of -α3.7 defect,54 out of 56 is -α3.7Ⅰ,2 out of 56 is -α3.7Ⅱ and none of -α3.7Ⅲ is detected.This result enriches the data about the alpha thalassemia genotypes of Chinese people.     

Beta-globin gene haplotypes and alpha-thalassemia analysis in Babinga pygmies from Congo-Brazzaville

We analyzed beta-globin gene cluster haplotypes and deletional alpha+-thalassemia (-alpha3.7kb) in 54 Babinga pygmy subjects from Congo-Brazzaville. The beta(S)-globin gene frequency was 0.065 and that of the deletional alpha-globin gene (-alpha3.7kb) was 0.29. Eighty-five percent of the beta(S) chromosomes and 13% of the beta(A) chromosomes were associated with the Bantu haplotype, 10% of beta(A) chromosomes with the Senegal haplotype, and the remaining beta chromosomes with atypical haplotypes. None of the chromosomes were of the Benin haplotype. These results are clearly of anthropological and evolutionary interest. They also support earlier observations that alpha+-thalassemia is prevalent at a high frequency in African populations.     

Dysfunctional alpha-globin gene in hemoglobin H disease in blacks. A dinucleotide deletion produces a frameshift and a termination codon

alpha-Thalassemia trait is common in Black Americans; the (-alpha) haplotype occurs in 30% of that population. However, hemoglobin H disease (genotype:- -/-alpha) is very uncommon due to the rarity of the (- -) haplotype. A subject with HbH-HbG Philadelphia (alpha 2(68)Asn----Lys) synthesized only alpha G and no alpha A. Digestion of DNA with BamHI produced a single 10-kilobase (kb) alpha-specific fragment. Her son had alpha-thalassemia trait, did not make HbG Philadelphia, and demonstrated 14- and 10-kb alpha fragments upon BamHI digestion. Since the 14-kb fragment could not have been inherited from the mother, the son apparently received from her a chromosome bearing a single nonfunctional (alpha T) gene. Therefore, the two genotypes are: mother (-alpha G/-alpha T), son (-alpha T/alpha alpha). A 16-kb BglII fragment, containing the gene of interest from the son, was cloned into the BamHI site of phage EMBL 3 followed by subcloning of a 1.5-kb PstI alpha-specific fragment into plasmid pBR322. The mutant alpha gene demonstrated a deletion of an AG dinucleotide from the tandem repeat normally occurring in the Glu-Arg codons 30 and 31 at the junction of the first exon with intervening sequence 1. The loss of two nucleotides leads to a reading frameshift and a totally novel amino acid coding sequence in the second exon from codons 31-54 followed by the appearance of a chain termination codon (TAA) at position 55. No complete globin chain can be produced from this gene. HbH disease in this Black family is thus due to the combination of gene deletion and a nonfunctional alpha gene.     

The binding sites for competitive antagonistic, allosteric antagonistic, and agonistic antibodies to the I domain of integrin LFA-1

We explore the binding sites for mAbs to the alpha I domain of the integrin alphaLbeta2 that can competitively inhibit, allosterically inhibit, or activate binding to the ligand ICAM-1. Ten mAbs, some of them clinically important, were mapped to species-specific residues. The results are interpreted with independent structures of the alphaL I domain determined in seven different crystal lattices and in solution, and which are present in three conformational states that differ in affinity for ligand. Six mAbs bind to adjacent regions of the beta1-alpha1 and alpha3-alpha4 loops, which show only small (mean, 0.8 angstroms; maximum, 1.8 angstroms) displacements among the eight I domain structures. Proximity to the ligand binding site and to noncontacting portions of the ICAM-1 molecule explains competitive inhibition by these mAbs. Three mAbs bind to a segment of seven residues in the beta5-alpha6 loop and alpha6 helix, in similar proximity to the ligand binding site, but on the side opposite from the beta1-alpha1/alpha3-alpha4 epitopes, and far from noncontacting portions of ICAM-1. These residues show large displacements among the eight structures in response to lattice contacts (mean, 3.6 angstroms; maximum, 9.4 angstroms), and movement of a buried Phe in the beta5-alpha6 loop is partially correlated with affinity change at the ligand binding site. Together with a lack of proximity to noncontacting portions of ICAM-1, these observations explain variation among this group of mAbs, which can either act as competitive or allosteric antagonists. One agonistic mAb binds distant from the ligand binding site of the I domain, to residues that show little movement (mean, 0.5 angstroms; maximum, 1.0 angstroms). Agonism by this mAb is thus likely to result from altering the orientation of the I domain with respect to other domains within an intact integrin alphaLbeta2 heterodimer.     

Oligonucleotide array for detection of common severe determinants of alpha thalassemia

A simple and an efficient oligonucleotide array was developed to identify common severe determinants of alpha (alpha) thalassemia. A total of 14 probes were designed to detect the most frequently three deletions (-alpha(3.7), -alpha(4.2), -(SEA)) and two non-deletions (alpha(Quong Sze), alpha(Constant Spring)). PCR products were amplified from human genomic DNA and allowed to hybridize with the oligonucleotide array. Hybridization was detected by fluorescence scanning, and alpha globin genotypes were assigned by quantitative analysis of the hybridization results. The efficiency and specificity of identifying alpha globin genotypes using the oligonucleotide arrays was evaluated by blinded analysis of 690 samples from unrelated individuals. The oligonucleotide array method described in this paper provides unambiguous detection of complex combinations of heterozygous, compound heterozygous and homozygous alpha thalassemia genotypes. The experimental results demonstrate that this methodological approach may be applied for screening and for hemological diagnosis in population at large.     

Distribution of plasma alpha-1-B-glycoprotein phenotypes in several Mongoloid populations of East Asia

The distribution of plasma alpha 1B-glycoprotein (alpha 1B) phenotypes was determined by a simple method of two-dimensional electrophoresis followed by protein staining in a group of 1,154 individuals from 8 Mongoloid populations of East Asia. The sample comprised 581 Chinese from different localities (Singapore: 204; Taiwan: 150; Fujien and Hopeh provinces of eastern China: 146 and 81), 155 Koreans, 155 Filipinos, 152 Thais and 111 Malays. Altogether, 6 different alpha 1B phenotypes (1-1, 1-2, 2-2, 1-3, 2-3, and 1-6) were observed. The alpha 1B allele frequencies were very similar in all of the populations. The frequency of A1B*1 varied from 0.89 to 0.91 and that of A1B*2 from 0.08 to 0.10. The A1B*3 allele, reported previously only in American blacks, was observed with a frequency range of 0.003-0.01 in 3 of the Chinese populations, in Koreans and in Malays. A new alpha 1B allele (A1B*6) was observed in 2 Chinese individuals.     

Structural studies on the sialic acid polysaccharide antigen of Escherichia coli strain Bos-12.

A polysaccharide, antigenically related to group C meningococcus, has been isolated from Escherichia coli strain Bos-12 (016; K92; NM). Like groups B and C meningococcal polysaccharide, the Bos-12 antigen is a pure polymer of sialic acid. 13C NMR studies on the meningococcal group B and C polysaccharides have indicated that the former consists of sialic acid units linked 2 leads to 8- alpha, whereas the latter contains the sialic acid residues linked 2 leads to 9-alpha (Bhattacharjee, A.K., Jennings, H.J., Kenny, C.P., Martin, A., and Smith, I.C.P. (1975), J. Biol. Chem. 250, 1926). Comparison of natural abundance 13C NMR spectra of the Bos-12 polysaccharide with group B and C meningococcal polysaccharides established that Bos-12 was either (a) an equimolar mixture of 2 leads to 8-alpha linked sialic acid homopolymers or (b) a 2 leads to 8-alpha/2 leads to 9-alpha heteropolymer. These possibilities were distinguished in the following manner. The fact that Bos-12 polysaccharide precipitated with anti-group C serum but not with anti-group B serum would seem to exclude a. Further, chemical studies (periodate oxidation followed by tritiated NaBH4 reduction) gave saccharides with a radioactive-labeling pattern expected for alternating 2 leads to 8-alpha/2 leads to 9-alpha sialic acid linkages. Bos-12 is thus an 2 leads to 8/2 lead to 9-alpha heteropolymer.     

Collagen IV alpha 3, alpha 4, and alpha 5 chains in rodent basal laminae: sequence, distribution, association with laminins, and developmental switches

Collagen IV is a major component of vertebrate basal laminae (BLs). Studies in humans have revealed a family of genes encoding alpha 1- alpha 6 collagen IV chains and implicated alpha 3-alpha 6 in disease processes (Goodpasture and Alport syndromes and diffuse leiomyomatosis). To extend studies of these components to an experimentally accessible animal, we cloned cDNAs encoding partial collagen alpha 3, alpha 4, and alpha 5(IV) chains from the mouse. Ribonuclease protection assays showed that all three genes were expressed at highest levels in kidney and lung; alpha 5(IV) was also expressed at high levels in heart. We then made antibodies specific for each collagen IV chain. Immunohistochemical studies of several tissues revealed many combinations of collagen IV chains; however, alpha 3 and alpha 4 (IV) were always coexpressed, and only appeared in BLs that were alpha 5(IV) positive. The alpha 3-alpha 5(IV) chains were frequently but not exclusively associated with the S (beta 2) chain of laminin, as were the alpha 1, 2 (IV) collagen chains with laminin B1 (beta 1). An analysis of developing rat kidney BLs showed that newly formed (S-shaped) nephrons harbored collagen alpha 1 and alpha 2(IV) and laminin B1; maturing (capillary loop stage) BLs contained collagen alpha 1-alpha 5(IV) and laminin B1 and S-laminin; and mature glomerular BLs contained mainly collagen alpha 3-alpha 5(IV) and S-laminin. Thus, collagen alpha 1 and alpha 2(IV) and laminin B1 appear to be fetal components of the glomerular BL, and there is a developmental switch to collagen alpha 3-alpha 5(IV) and S-laminin expression.     

Molecular basis for HbH disease in Italy: geographical distribution of deletional and nondeletional alpha-thalassemia haplotypes.

We have investigated the molecular basis for HbH disease in 16 patients from Sardinia, and central and southern Italy. We have shown that HbH disease is produced by the interaction of at least 10 different deletional or nondeletional alpha-thalassemia haplotypes, some of which have been already described in the Mediterranean area (--Med,-(alpha)20.5,-alpha 3.7 type I,-alpha 3.7 type II, alpha 2 NcoI alpha 1, alpha 2 HphI alpha 1). Among the new mutations found in the course of our study, there is a complete deletion of the zeta-alpha cluster and three nondeletional determinants (alpha alpha T), affecting to various extents alpha-globin gene expression. The different alpha-thalassemia haplotypes are not evenly distributed throughout the country. Two alpha 0 determinants [-(alpha)20.5 and the complete deletion of the zeta-alpha cluster] and four alpha + determinants (-alpha 3.7 type II, three nondeletional alpha alpha T mutations) are found exclusively in southern Italy.     

Characterization of four G0-type proteins purified from bovine brain membranes

Recently we reported there were at least four types of G0 or G0-like proteins in bovine brain membranes based on their elution profiles from Mono Q columns and their immunological reactivities; one of the proteins was purified as an alpha-monomeric form, and the others as alpha beta gamma-trimers. The four proteins, of which alpha-subunits were confirmed to be a family of G0-type by an immunoblot analysis, were thus referred to as alpha (0)1, G(0)2, G(0)3 and G(0)4, respectively, in order of their elutions from the column. Immunostained peptide mappings arising from proteolytic digestions of the four alpha-subunits, together with their fragmentation patterns containing radiolabeled ADP-ribose that had been incorporated by pertussis toxin-catalyzed ADP-ribosylation, suggested that the four G0-alpha were classified into either of two groups such as alpha (0)1 and G(0)2-alpha, or G(0)3-alpha and G(0)4-alpha. The kinetic parameters of their GTPase activities, however, revealed that there were different properties between alpha (0)1 and G(0)2-alpha or G(0)3-alpha and G(0)4-alpha. Thus, the four G0-type proteins appeared to be different entities from one another.     

Molecular analysis of alpha/beta-thalassemia in a southern Chinese population

Thalassemia is endemic to many regions in southern China. The screening of severe determinants of thalassemia is of critical importance in management and control of thalassemia. We designed a protocol based on microarray technology to screen for a spectrum of alpha/beta-globin gene mutations in the Chinese population. A total of 38 probes were capable of screening 98% of alpha/beta-globin gene mutations in the China population, including 16 mutations of beta-globin [beta(41-42)(-TCTT), IVSII-654(C-->T), beta17(A-->T), -28(A-->G), beta(71-72)(+A), beta(71-72)(+T), HbE26(G-->A), -29(A-->G), beta(27-28)(+C), IVSI-1(G-->T), IVSI-5(G-->C), beta(14-15)(+G), IVSII-5(G-->C), beta41(+T), 37(G-->A), and beta43(G-->T)] and five mutations of alpha/beta[three deletions of -alpha;(3.7), -alpha(4.2), and --(SEA); two nondeletions of alpha(Quong Sze) codon alpha125(T-->C) and alpha(Constant Spring) codon alpha142(T-->C)]. Multiplex PCR products were amplified from human genomic DNA and allowed to hybridize with the oligonucleotide array. alpha/beta-Globin genotypes were assigned by quantitative analysis of the hybridization results. The protocol, standardized by analysis of 100 thalassemia samples with known mutations and 13 recombinant plasmids, was 100% reliable in genotyping all mutant alleles. In subsequent screening of 2,030 Chinese with unknown mutations, the protocol was 100% accurate. This method provides unambiguous detection of complex combinations of heterozygous, compound heterozygous, and homozygous alpha/beta-thalassemia genotypes. The protocol was also flexible, detecting globin gene mutations from different population groups.     

Increased susceptibility of malaria-infected variant erythrocytes to the mononuclear phagocyte system

The interactions of the mononuclear phagocyte system with Plasmodium falciparum-infected genetically variant erythrocytes may result in a significant protection for the host. Infected hemoglobin (Hb) EE and Hb EA erythrocytes are more susceptible to phagocytosis by monocytes than are infected Hb AA erythrocytes. The increased susceptibility to phagocytosis of infected erythrocytes was also found for a number of genetic variants involving the alpha-globin chain, namely, alpha-thal 1 trait (--/alpha alpha), alpha-thal 2 trait (-alpha/alpha alpha), Hb H (--/-alpha), Hb H/Hb Constant Spring (CS) (--/alpha CS alpha), Hb CS trait, and homozygous Hb CS erythrocytes. In addition, oxidative damage from hydrogen peroxide, produced in simulation of macrophages, led to much more effective killing of parasites in glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes than in normal ones. Parasites infecting Hb H/Hb CS also showed an enhanced sensitivity to hydrogen peroxide.