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H W Li

Publications and source records attributed to H W Li.

14 recordsLinked to original sources
PubMed1991

A Czechoslovakian teenager with Hb E-beta zero-thalassemia [IVS-I-1 (G----A)] complicated by the presence of an alpha-globin gene triplication.

We have examined the molecular basis of three inherited hemoglobin (Hb) disorders present in a Czechoslovakian girl with a severe, transfusion-dependent, hemolytic anemia. She is heterozygous for Hb E (on a genetic background specific for Czechoslovakian families), heterozygous for the beta zero-thalassemia (thal) allele IVS-I-1 (G----A), and heterozygous for an alpha-globin gene triplication. The combination of these three undesirable traits results in a severe chain imbalance that is the basis of the serious hemolytic disorder observed in this teenager.

Adolescent↗
PubMed1991

Beta-thalassemia, HB S-beta-thalassemia and sickle cell anemia among Tunisians.

We analyzed the mutations present in 19 patients with beta-thalassemia major, in 11 patients with Hb S-beta-thalassemia, and the beta S haplotypes of 34 patients with sickle cell anemia. The study included 84 relatives. Dot-blot analysis of amplified DNA with various specific oligonucleotide probes identified 11 different known beta-thalassemia mutations and frameshifts; a new frameshift at codons 25/26 (+T) was detected through sequencing of amplified DNA. The common beta-thalassemia mutations at codon 39 (C----T) and at IVS-I-110 (G----A) were also most prevalent among the Tunisian patients, while the milder T----C mutation at IVS-I-6 was not found. All mutations cause a beta 0-thalassemia or a severe beta + -thalassemia [T----A at -30; IVS-I-5 (G----A); IVS-I-110 (G----A)] which explains the need for regular blood transfusions in the thalassemia major and S-beta-thalassemia patients. Nearly all sickle cell anemia patients carried the beta S mutation on a chromosome with haplotype 19 (or Benin) and all had severe anemia with sickling complications. Identification of the beta S haplotype was through dot-blot analysis with oligonucleotide probes that detect mutations in the G gamma and A gamma promoter sequences, specific for this haplotype.

Adolescent↗
PubMed1991

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.

Adult↗
PubMed1990

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.

Adolescent↗
PubMed1990

Abnormal hemoglobins in the Silk Road region of China.

A review is presented of the occurrence of 24 abnormal hemoglobins (13 alpha-chain variants and 11 beta-chain variants) in populations in the Silk Road area of Northwestern China. Most frequently occurring were Hb D-Punjab [beta 121(GH4)Glu----Gln] in Uygurs, Kazaks, and Khalkhas, Hb G-Taipei [beta 22(B4)Glu----Gly] in persons of the Han nationality, and Hb G-Coushatta [beta 22 (B4)Glu----Ala] in the Uygurs, Kazaks, Hans, and related nationalities. The data suggest that these variants likely originated in Central Asia, in the Han nationality of China, and in the minorities of northern China, respectively. Other variants occurred at considerably lower frequencies and were imported from other countries or arose as independent mutations. Two variants [Hb Tashikuergan or alpha 19(AB1)Ala----Glu; Hb Tianshui or beta 39(C5) Gln----Arg] were observed for the first time. The data from this study of the many variants support the movements of various populations in this area, as reported in numerous historical documents.

China↗
PubMed1990

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.

Adult↗
PubMed1989

Difference spectrophotometric assay of nitrazepam in tablet formulations.

A difference spectrophotometric procedure is described for the assay of nitrazepam in tablet formulations. The method is based on the measurement of absorbance at 282 nm of a solution of the tablet extract in 0.1 M hydrochloric acid (pH 1) relative to that of an equimolar solution in 0.1 M sodium hydroxide (pH 13). The method is precise and selective for nitrazepam in the presence of the tablet excipients and 2-amino-5-nitrobenzophenone, the principal hydrolysis product of nitrazepam. The absence of a constant isosbestic point in the difference spectrum of nitrazepam during hydrolysis in alkaline solution indicates the presence of a previously unrecognized intermediate hydrolysis product.

Hydrogen-Ion Concentration↗
PubMed1988

Thalassemia in the Silk Road region of China.

This paper summarizes data obtained during a screening program involving 11,563 persons from the Silk Road region in China. The mean incidence of thalassemia is 1.62% with an increase from east to west. The incidence in the Hui population (3.01%) is higher than in Kazaks (2.92%), and in Uygur (2.22%). The Han population also has a higher incidence (0.98%) than seen for other regions in Northern China. The thalassemias observed are classified into seven groups; beta-thalassemia accounts for 89.48% of the total, and alpha-thalassemia for 10.52%.

China↗
PubMed1985

Determination of the energetic cost of swimming from the analysis of growth rate and body composition in juvenile chinook salmon, Oncorhynchus tshawytscha.

The standard metabolic rate was estimated to be 19.5 cal X kcal-1 X day-1. The multiple regression of growth on swimming speed and ration size was significant (P less than 0.001). The relationship was as follows: G = 22.22-2.85BL + 6.58 R where G is growth in cal X kcal X day-1, BL represents swimming speed in body lengths X sec-1 and R denotes ration in % body wt X day-1, dry weight. The multiple correlation coefficient, R2, was 0.80. Unlike coho salmon, the net cost of swimming was independent of swimming speed. Fish in all groups experienced reduction of fat with exercise with the exception of the slowest speed-highest ration (1.0-1.9 BL X sec-1, 6% X day-1) group. Nearly all of the explained variation was accounted for by food consumption rate.

Aging↗