Diffusive liquid propagation in porous and elastic materials: the case of foams under microgravity conditions.

We report the results of fluid transport experiments in aqueous foams under microgravity. Using optical and electrical methods, the capillary motion of the foam fluid and the local liquid fractions are monitored. We show that foams can be continuously wetted up to high liquid fractions ( approximately 0.3), without any bubble motion instabilities. Data are compared to drainage models: For liquid fractions above 0.2, discrepancies are found and identified. These new results on foam hydrodynamics and structure can be useful for other poroelastic materials, such as plants and biological tissues.

Two different forms of homozygous sickle cell disease occur in Saudi Arabia.

Haematological, clinical and some molecular genetic features of homozygous sickle cell (SS) disease in Saudi Arabia have been compared in 33 patients from the Eastern Province (Eastern) and 30 from the South Western Province (Western). Eastern patients all had the Asian beta globin haplotype whereas Western patients were more variable but predominantly of the Benin haplotype. Eastern patients had more deletional alpha thalassaemia, higher total haemoglobin and fetal haemoglobin levels, and lower HbA2, mean cell volume, reticulocytes, and platelet counts. Clinically, Eastern patients had a greater persistence of splenomegaly, a more normal body build and greater subscapular skin fold thickness, and Western patients had more dactylitis and acute chest syndrome. Painful crises and avascular necrosis of the femoral head were common and occurred equally in both groups. The disease in the Eastern province has many mild features consistent with the higher HbF levels and more frequent alpha thalassaemia but bone pathology (painful crises, avascular necrosis of the femoral head, osteomyelitis) remains common. The disease in the West is more severe consistent with the Benin haplotype suggesting an African origin.

The proximal element of the beta globin locus control region is not functionally required in vivo.

In addition to local sequence elements the regulation of the high-level, development- and tissue-specific expression of the human beta globin gene cluster appears to require distant regulatory sequences which have been termed locus control region. In the chromatin of erythroid cells the locus control region is characterized by four DNaseI hypersensitive sites that are located 6-18 kb 5' of the epsilon globin gene. The definition of the sequences minimally required for locus control region activity is likely to further the understanding of its physiology and will be of interest for the development of somatic gene therapy strategies of the hemoglobinopathies. We present here the analysis of a family with a 3,030-bp deletion of sequences upstream of the epsilon globin gene including the most 3' locus control region element and cosegregating beta(0) thalassemia. The deletion is linked in cis to a structurally and functionally normal beta globin gene. The proximal element of the locus control region does not therefore appear to be necessary for beta globin gene activity in vivo.

Thalassemia intermedia: moderate reduction of beta globin gene transcriptional activity by a novel mutation of the proximal CACCC promoter element.

A patient with homozygous beta thalassemia of German/Italian descent was found to be doubly heterozygous for the common IVS1-110 G----A mutation of the beta globin gene and for a novel C----T mutation of the proximal CACCC-box of the beta globin gene promoter at position -87 relative to the transcription start site (cap). Transcription analysis in an HeLa cell transfection assay indicated a 45% to 51% residual activity of the gene with the -87 C----T mutation relative to normal, further underlining the physiologic role of the affected promoter element. The finding of an only moderately reduced transcriptional activity of the beta globin gene with the -87 C----T mutation corresponds well with the clinical phenotype of the reported patient, which is characterized by a late onset of symptoms, moderate anemia, and normal physical development. The ethnically German mother of the propositus has minimal anemia with only slightly changed red blood cell indices, which can also be explained by the relatively high residual activity of the gene with the -87 C----T mutation.

Two different forms of homozygous sickle-cell disease - abstract

Haematological, clinical and some molecular genetic features have been compared in two groups of patients with homozygous sickle-cell (SS) disease in Saudi Arabia, 33 patients from the Eastern Province (eastern) and 30 from the South Western Province (Western). Eastern patients all had the Asian haplotype of DNA polymorphisms within the beta globin gene cluster whereas Western patients were more variable but predominantly of the Benin haplotype. Eastern patients had significantly more deletional alpha thalassaemia, higher levels of total haemoglobin and foetal haemoglobin, and lower of HBA, mean volume reticulocytes, and platelets. Clinically, Eastern patients had a greater persistence of splenomegaly, less dactylitis, less acute chest syndrome, a more normal body build and greater subscapular skin fold thickness. Painful crises occurred with equal frequency in both groups. Avascular necrosis of the femoral head was common in both groups. The disease in the Eastern province has many mild features consistent with the higher HbF levels and more frequent alpha thalassaemia but bone pathology (painful crises, avascular necrosis of the femoral head, osteomyelitis) remains common. The disease in the West is more severe, consistent with the Benin haplotype suggesting an African origin (AU)

Sickle cell-beta+ thalassaemia in Orissa State, India.

The clinical, haematological, and some molecular genetic features of 17 Orissan Indian patients with sickle cell-beta+ thalassaemia (S beta+ thal) are described and compared with those in 131 Indian patients with homozygous sickle cell (SS) disease. Patients with S beta+ thal had higher Hb A2 levels, and lower mean cell volume (MCV) and mean cell haemoglobin (MCH) compared to SS disease but no other haematological difference of statistical significance. High levels of Hb F occurred in both genotypes and the alpha+ thalassaemia gene frequency reached 0.47 in S beta+ thal and 0.32 in SS disease. Clinically there were no significant differences between the genotypes indicating that the low levels of HbA (3-5%) in this condition were insufficient to modify the clinical features. The thalassaemic beta globin gene is inactivated by a G----C mutation at position 5 of the first intron of the beta globin gene (IVS1-5 G----C) in all cases. This finding should facilitate the introduction of a prenatal diagnosis programme aimed at the prevention of beta thalassaemia or S beta+ thalassaemia in that population.

Tin-protoporphyrin suppression of hyperbilirubinemia in the jaundiced Gunn rat.

Suppression of hyperbilirubinemia was studied in jaundiced adult and neonatal Gunn rats following treatment with tin-protoporphyrin. The effects of tin-protoporphyrin treatment on heme oxygenase, NADPH cytochrome c reductase, and biliverdin reductase activities were studied in adult jaundiced Gunn rat renal, hepatic and splenic tissues. Hepatic heme oxygenase activity was studied in nonjaundiced and jaundiced Gunn neonates. Significant decreases in plasma bilirubin levels were observed for both adult and neonatal rats treated with 50 or 100 mumol tin-protoporphyrin/kg body weight. Tin-protoporphyrin-treated rats had significantly lower hepatic and renal heme oxygenase activities, splenic and renal cytochrome c reductase activities, and a significantly higher splenic biliverdin reductase activity. Hepatic heme oxygenase activity was also significantly reduced in the neonatal rats.

Transfer of the heritable nonhemolytic jaundice trait from the Gunn rat to the Sprague-Dawley rat.

Congenital nonhemolytic jaundice as observed in the Gunn rat was transferred successfully to the Sprague-Dawley rat. This jaundice trait occurs as the result of a deficiency of bilirubin glucuronyltransferase and appeared to transfer by simple Mendelian inheritance. A comparison of jaundiced Gunn with jaundiced Gunn-Sprague-Dawley cross rats for plasma bilirubin level, bilirubin glucuronyltransferase activity and female reproductive performance showed no significant difference between the two jaundiced rat groups. The phenotypic expression of the jaundice trait as viewed by the parameters used in this study appeared to be the same for both the Gunn and Gunn-Sprague-Dawley cross rats. The transfer of the jaundice trait to another rat strain enhances the opportunity to characterize this animal model and to determine the possible influence of a long-term closed mating system.