von Willebrand factor and von Willebrand disease [published erratum appears in Blood 1988 Mar;71(3):830]

Progress has occurred in the past several years in the understanding of the structure and function of von Willebrand factor (vWF). This multimeric glycoprotein exhibits a dual role, that of mediating platelet adhesion and aggregation onto thrombogenic surfaces, and that of functioning as carrier in plasma for the factor VIII procoagulant protein. New insights into the nature of the several functional domains of vWF have led to the identification of the regions of the molecule that interact with factor VIII, heparin, the glycoprotein lb of platelets, and collagen. Alterations of vWF are the cause of von Willebrand disease (vWD), a congenital bleeding disorder. In the majority of patients, the plasma levels of vWF are decreased, but there is no demonstrable structural or functional alteration of the protein. In other patients, however, the structure of vWF is abnormal. This review summarizes the current knowledge on vWF and vWD.     

Enhancement by dimethyl myleran of donor type chimerism in murine recipients of bone marrow allografts

A major problem in using murine models for studies of bone marrow allograft rejection in leukemia patients is the narrow margin in which graft rejection can be analyzed. In mice irradiated with greater than 9 Gy total body irradiation (TBI) rejection is minimal, whereas after administration of 8 Gy TBI, which spares a significant number of clonable T cells, a substantial frequency of host stem cells can also be detected. In current murine models, unlike in humans, bone marrow allograft rejection is generally associated with full autologous hematopoietic reconstitution. In the present study, we investigated the effect of the myeloablative drug dimethyl myleran (DMM) on chimerism status following transplantation of T cell-depleted allogenic bone marrow (using C57BL/6 donors and C3H/HeJ recipients, conditioned with 8 Gy TBI). Donor type chimerism 1 to 2 months post-transplant of 1 to 3 x 10(6) bone marrow cells was markedly enhanced by using DMM one day after TBI and prior to transplantation. Conditioning with cyclophosphamide instead of DMM, in combination with 8 Gy TBI, did not enhance engraftment of donor type cells. Artificial reconstitution of T cells, after conditioning with TBI plus DMM, by adding mature thymocytes, or presensitization with irradiated donor type spleen cells 1 week before TBI and DMM, led to strong graft rejection and consequently to severe anemia. The anti-donor responses in these models were proportional to the number of added T cells and to the number of cells used for presensitization, and they could be neutralized by increasing the bone marrow inoculum. These results demonstrate the potential of DMM to facilitate engraftment in unsensitized mice in which the host stem cells may compete with donor type cells; the use of DMM to create models in which mechanisms of immune rejection can be studied without interference due to stem cell competition; and that bone marrow allograft rejection may be overcome by increasing the bone marrow inoculum in these stringent models.     

Thrombocytopenia in the neonatal lupus syndrome

Thrombocytopenia has been documented infrequently in association with congenital heart block or lupus dermatitis in the neonatal lupus erythematosus syndrome. We report the cases of two infants with transient neonatal thrombocytopenia born to mothers with connective-tissue disease. Both mother/infant pairs were Ro(SS-A) antibody positive. Although the finding of neonatal thrombocytopenia in the presence of maternal connective-tissue disease suggests an autoimmune thrombocytopenia, platelet antibody studies were negative in both mother/infant pairs. We have found the Ro (SS-A) antibody with increased frequency in idiopathic thrombocytopenic purpura and thrombocytopenia associated with Sj?gren's syndrome, but the nature of the association is unknown. We suggest that thrombocytopenia in our patients is a manifestation of the neonatal lupus erythematosus syndrome. This syndrome should be included in the differential diagnosis of neonatal thrombocytopenia.     

Vitamin D Deficiency as a Factor Influencing Asthma Control in Children

Objective

To study the association between asthma control and serum 25OH Vitamin D levels in children with moderate persistent asthma on preventer therapy.

Methods

Children aged 6–18 years, with moderate persistent asthma, on preventer therapy for ≥2 months were included. Control was categorized as good, partial or poor as per GINA guidelines. Serum 25 (OH) Vitamin D levels were measured and their relationship with the level of control was studied.

Results

Out of 50 children enrolled, 22 had well-controlled asthma, and 21 had partially controlled asthma. Vitamin D was deficient in 30 children and insufficient in 18 children. Children with vitamin D deficiency had significantly less wellcontrolled asthma as compared to those with insufficient or sufficient levels of 25 (OH) vitamin D (13.3% vs 88.9 % vs 100%).

Conclusion

Vitamin D deficiency is associated with suboptimal asthma control.

     

Correction: Propensity-matched analysis of patients with intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma and hepatocellular carcinoma undergoing a liver transplant

Rereading the article “Propensity-matched analysis of patients with intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma and hepatocellular carcinoma undergoing a liver transplant” (DOI: 10.5306/wjco.v13.i8.688), published on August 24, we observe, with concern, that figures 3 and 4 are wrong. The authors have attached the correct figures for correction.