Alpha Globin Gene Mutation: A Major Determinant of Hydroxyurea Response in Transfusion-Dependent HbE-ß-Thalassaemia.

Thalassaemias are the most common inherited autosomal recessive single gene disorders characterised by chronic hereditary haemolytic anaemia due to absence or reduced synthesis of one or more of the globin chains. Haemoglobin E (HbE)-ß-thalassaemia is the genotype responsible for approximately one-half of all cases of severe ß-thalassaemia worldwide. This study proposes to evaluate response of hydroxyurea in reducing transfusion requirements of severe HbE-ß-thalassaemia patients, and its correlation with foetal haemoglobin (HbF) level and α-mutation. Hydroxyurea was started at a baseline dose in 82 transfusion-dependent HbE-ß-thalassaemia patients. HbF levels and %F-cells were measured. ß-Thalassaemia mutations and α-globin gene deletions and triplications were detected by amplification refractory mutation system (ARMS)-polymerase chain reaction (PCR) and Gap-PCR, respectively. Patients were categorised as good (41.5%), moderate (31.7%), and poor responders (26.8%) based on their decrease in transfusion requirements. Nine patients were excellent responders who became transfusion independent. The mean increase in HbF levels and %F-cells after therapy was correlated with decrease in transfusion requirements. Patients having a deletion of the α-globin gene were better responders. The response was proportional to the number of α-globin gene deletions. We conclude that hydroxyurea treatment decreases transfusion requirements, and the response correlates with α-globin gene deletions.

Genetic determinants related to pharmacological induction of foetal haemoglobin in transfusion-dependent HbE-ß thalassaemia.

Thalassaemia are the most common inherited autosomal recessive single gene disorders characterized by chronic hereditary haemolytic anaemia due to the absence or reduced synthesis of one or more of the globin chains. Haemoglobin E-ß thalassaemia is the genotype responsible for approximately one half of all severe beta-thalassaemia worldwide. This study proposes to evaluate the effect of various molecular parameters on the response of hydroxyurea. Hydroxyurea was started at an initial dose of 10 mg/kg of body weight/day on 110 transfusion-dependent HbE-ß thalassaemia patients. HbF level was measured by HPLC analysis. ß-Thalassaemia mutations, XmnI and five other SNPs, and α-globin gene deletions and triplications were detected by ARMS-PCR, RFLP-PCR and Gap-PCR, respectively. Based on the factors for evaluating hydroxyurea-response, 42 patients were responders as they showed an increment of Hb from a mean baseline value of 6.45 g/dl (± 0.70) to 7.78 g/dl (± 0.72) post-therapy. Based on increase in HbF above the median value (14.72%) post-therapy, 78 patients were found to be responders. All the 78 responders showed mean decrease in transfusion of 74.26% (± 8.32) with a maximum decrease of 98.43%. There was a significant correlation between decrease in transfusion and increase in HbF level for all 78 responders. XmnI polymorphism showed the strongest association (p < 0.0001) with increase in HbF levels and Hb levels. Patients with α-globin gene deletions were better responders. It was concluded that hydroxyurea treatment is effective in transfusion-dependent HbE-ß thalassaemia patients and the response is best in patients having both XmnI polymorphism and α-deletion.

Discovery of pyrazole carboxylic acids as potent inhibitors of rat long chain L-2-hydroxy acid oxidase.

Long chain L-2-hydroxy acid oxidase 2 (Hao2) is a peroxisomal enzyme expressed in the kidney and the liver. Hao2 was identified as a candidate gene for blood pressure (BP) quantitative trait locus (QTL) but the identity of its physiological substrate and its role in vivo remains largely unknown. To define a pharmacological role of this gene product, we report the development of selective inhibitors of Hao2. We identified pyrazole carboxylic acid hits 1 and 2 from screening of a compound library. Lead optimization of these hits led to the discovery of 15-XV and 15-XXXII as potent and selective inhibitors of rat Hao2. This report details the structure activity relationship of the pyrazole carboxylic acids as specific inhibitors of Hao2.

Potent and Selective Inhibitors of Long Chain l-2-Hydroxy Acid Oxidase Reduced Blood Pressure in DOCA Salt-Treated Rats.

l-2-Hydroxy acid oxidase (Hao2) is a peroxisomal enzyme with predominant expression in the liver and kidney. Hao2 was recently identified as a candidate gene for blood pressure quantitative trait locus in rats. To investigate a pharmacological role of Hao2 in the management of blood pressure, selective Hao2 inhibitors were developed. Optimization of screening hits 1 and 2 led to the discovery of compounds 3 and 4 as potent and selective rat Hao2 inhibitors with pharmacokinetic properties suitable for in vivo studies in rats. Treatment with compound 3 or 4 resulted in a significant reduction or attenuation of blood pressure in an established or developing model of hypertension, deoxycorticosterone acetate-treated rats. This is the first report demonstrating a pharmacological benefit of selective Hao2 inhibitors in a relevant model of hypertension.

Cascade synthesis of (E)-2-alkylidenecyclobutanols.

A facile, one-pot reaction cascade condenses 1,1,1-trichloroalkanes with alpha,beta-unsaturated ketones to unexpectedly furnish moderate to good yields of (E)-2-alkylidenecyclobutanols.

Stereospecific cross-coupling of alpha-(thiocarbamoyl)organostannanes with alkenyl, aryl, and heteroaryl iodides.

Racemic and scalemic PTC-protected alpha-hydroxystannanes cross-couple with alkenyl/aryl/heteroaryl iodides in moderate to good yields using copper(I) thiophene-2-carboxylate (CuTC) in THF at or below room temperature. Simple aryl iodides and 1-iodocyclohexene, two classes of electrophiles that typically react sluggishly, are also good substrates. Cross-couplings proceed with retention of configuration at the alkenyl- and stannyl-substituted stereocenters.

Fe(0)-mediated synthesis of tri- and tetra-substituted olefins from carbonyls: an environmentally friendly alternative to Cr(II).

Fe(0) was investigated as a cost-effective, environmentally friendly alternative to Cr(II) for the olefination of carbonyls by activated polyhalides. In many instances, Fe(0) was equivalent or superior to Cr(II). Notably, Fe(0), but not Cr(II), proved compatible with a wide range of functionality, inter alia, unprotected phenol, aryl nitro, carboxylic acid, and alkyl nitrile. A surprising reversal of stereoselectivity for aldehydes versus ketones was observed using both metals. The resultant alpha-halo-alpha,beta-unsaturated or alpha,beta-unsaturated carboxylic acids, esters, and nitriles are common structural elements in numerous compounds of interest as well as key intermediates in the preparation of other functionality.