Hb Dartmouth [alpha66(E15)Leu-->Pro (alpha2) (CTG-->CCG)]: a novel alpha2-globin gene mutation associated with severe neonatal anemia when inherited in trans with Southeast Asian alpha-thalassemia-1.

We report a novel mutation at alpha66(E15)Leu-->Pro (alpha2) (CTG-->CCG), that we have named Hb Dartmouth for the medical center at which the patients were cared for, in monozygotic twins who also inherited the Southeast Asian alpha-thalassemia-1 deletion. The mother, of Khmer ancestry, is heterozygous for alpha-thalassemia-1. The father, who is of Scottish-Irish ancestry, is a silent carrier of the codon 66 mutation. The twins had severe neonatal anemia requiring transfusion.     

Incidence and mortality of acute and chronic pancreatitis in the Netherlands:A nationwide record-linked cohort study for the years 1995-2005

AIM:To analyze trends in incidence and mortality of acute pancreatitis(AP) and chronic pancreatitis(CP) in the Netherlands and for international standard populations.METHODS:A nationwide cohort is identified through record linkage of hospital data for AP and CP,accumulated from three nationwide Dutch registries:the hospital discharge register,the population register,and the death certificate register.Sex-and age-group specific incidence rates of AP and CP are defined for the period 2000-2005 and mortality rates of AP and CP for the period 1995-2005.Additionally,incidence and mortality rates over time are reported for Dutch and international(European and World Health Organization) standard populations.RESULTS:Incidence of AP per 100000 persons per year increased between 2000 and 2005 from 13.2(95%CI:12.6-13.8) to 14.7(95%CI:14.1-15.3).Incidence of AP for males increased from 13.8(95%CI:12.9-14.7) to 15.2(95%CI:14.3-16.1),for females from 12.7(95%CI:11.9-13.5) to 14.2(95%CI:13.4-15.1).Irregular patterns over time emerged for CP.Overall mean incidence per 100000 persons per year was 1.77,for males 2.16,and for females 1.4.Mortality for AP fluctuated during 1995-2005 between 6.9 and 11.7 per million persons per year and was almost similar for males and females.Concerning CP,mortality for males fluctuated between 1.1(95%CI:0.6-2.3) and 4.0(95%CI:2.8-5.8),for females between 0.7(95%CI:0.3-1.6) and 2.0(95%CI:1.2-3.2).Incidence and mortality of AP and CP increased markedly with age.Standardized rates were lowest for World Health Organization standard population.CONCLUSION:Incidence of AP steadily increased while incidence of CP fluctuated.Mortality for both AP and CP remained fairly stable.Patient burden and health care costs probably will increase because of an ageing Dutch population.     

Kringle glycosylation in a modified human tissue plasminogen activator improves functional properties

Native tissue plasminogen activator (ntPA) has a variable glycosylation site on its kringle-2 domain. We have examined the effects of kringle glycosylation on functional properties by studying the simplified tPA molecule, tPA-6. tPA-6 is composed of kringle-2 and the serine protease domains and, like ntPA, cells expressing tPA-6 process it into two glycoforms: the monoglycosylated tPA-6-primary (tPA-6P, type II) with N- linked glycosylation at Asn-448 in the serine protease domain and diglycosylated tPA-6-variant (tPA-6V, type I) with glycosylation at Asn- 448 and at Asn-184 in kringle-2. When the two glycoforms were separated, we found that purified tPA-6V had reduced fibrin-stimulated plasminogenolytic activity toward Glu-plasminogen when compared to purified tPA-6P. However, in the presence of fibrin, tPA-6V unexpectedly exhibited a sixfold increase in selectivity toward Lys- plasminogen. In addition, tPA-6V was less susceptible than tPA-6P to plasmin-mediated conversion to the two-chain form. By site-directed mutagenesis of tPA-6, we eliminated variable glycosylation at Asn-184 and engineered a new glycosylation signal at a remnant site in the kringle. This derivative, designated tPA-6D, was secreted with complete kringle glycosylation. Like the naturally occurring tPA-6V, tPA-6D had lower rates of fibrin-stimulated Glu-plasminogen activation, increased specificity toward Lys-plasminogen, and greater resistance to plasmin digestion. Although the activity of tPA-6D could be stimulated by fibrin, its activity was not stimulated significantly by fibrinogen, and in human plasma the rate of fibrinogen depletion was reduced threefold. Although fibrin binding to kringle-2 of tPA-6D was slightly improved, there was a substantial increase in the dissociation constant (kd) for lysine binding, demonstrating a lack of correlation between these ligand-binding sites. Overall, our data demonstrate the marked effect of kringle glycosylation on functional properties. In addition, we have generated a derivative with properties that potentially improve clot specificity and single-chain half-life and reduce the potential for plasminogen activation in the plasma.