DDAVP infusion in haemophilia A carriers: different behaviour of plasma factor VIII and von Willebrand factor.

1-desamino-8-D-arginine vasopressin (DDAVP) increases factor VIII (FVIII) and von Willebrand factor (vWF) levels in patients with haemophilia A and in some patients with von Willebrand disease. It is generally held that the increase of FVIII is a consequence of the increase of vWF. Carriers of haemophilia A generally, but not always, show plasma FVIII levels lower than vWF due to an abnormality in one of the two alleles of the FVIII gene. We investigated the time-course of plasma FVIII:C and vWF:Ag levels in 25 obligate carriers of haemophilia A after DDAVP infusion. In carriers with a normal FVIII to vWF ratio (> 0.8), DDAVP induced a progressive ratio decrease that reached levels significantly lower than that taken as cut-off to discriminate between low and normal values (0.68 +/- 0.1 vs before 0.912 +/- 0.18). In carriers with a borderline (0.7-0.8) or reduced (< 0.7) ratio DDAVP induced a further decrease in the FVIII/vWF ratio, albeit with a different kinetic; after an initial increase, values were lower than pre-DDAVP figures. In all subjects, following the post-DDAVP peak, plasma FVIII progressively decreased while vWF contemporaneously continued to increase. In contrast, DDAVP did not induce significant changes in the FVIII/vWF ratio in normal females, and the two molecules appeared to increase similarly throughout the observation period. These findings indicate that after DDAVP, FVIII increases less or for a shorter time than vWF, also in haemophilia A carriers who have a normal FVIII/vWF ratio. Hence, DDAVP may help identify haemophilia A carriers, especially subjects with normal or borderline ratios. Even though molecular biology procedures at present are the best and more reliable tools to identify the carrier state, DDAVP seems to improve the accuracy of haemostatic parameters.

Primary hyperfibrinogenolysis in a patient with anaphylactic shock.

Although systemic hyperfibrino(geno)lysis during hypotensive crisis is known, there do not seem to be recent reports of episodes of primary acute fibrinogenolysis during anaphylactic shock. We report the case of a 61-year-old male admitted to the hospital for anaphylactic shock due to an insect bite who presented a clinical and laboratory picture of severe acute generalized hyperfibrinogenolysis not secondary to disseminated intravascular coagulation (DIC). Without specific therapy, the clinical picture resolved itself spontaneously within 40 hours of onset. Careful clinical examination and the execution of simple laboratory tests permitted a rapid diagnosis and therapeutic success.

Presence of anti-Yta antibody in a Yt(a+) patient.

Since 1956 when Cartwright (Yt) was recognized as a new erythrocyte antigenic system, numerous studies about anti-Yta and anti-Ytb antibodies have been published. A number of these studies described the laboratory techniques utilized in antibody identification, while others investigated the clinical importance of anti-Yta, giving variable results. However, most authors agreed upon the homogeneity of expression in this antigenic system. In our study we have described a case regarding 1 Yt(a+) patient with anti-Yta antibody. Family studies indicated inheritance of a variant/variant expression of the Yta antigen from the father.

Combined factor VIII and factor XI congenital deficiency: a case report.

Combined congenital defect involving both Factor VIII and XI is a very rare disorder. We describe a case of combined Factor VIII and XI deficiency in which the propositus has a mild hemophilia A and inherited a Factor XI deficiency from the father. Moreover, we report on the benefit of DDAVP administration to the patient during a bleeding episode.

Erythrocyte endogenous proteinase activity during blood bank storage.

We studied proteolytic alterations of membrane proteins in ghosts derived from human red blood cells, preserved up to 35 days in the liquid state either as whole blood or with additive solution. The study was carried out by performing sodium dodecyl sulfate polyacrylamide gel electrophoresis of stromal proteins from erythrocytes, either previously treated with proteinase inhibitors or previously incubated in conditions promoting proteolysis. To differentiate the effect of erythrocyte from granulocyte proteinases, the investigation was also carried out in leukocyte-free red cell preparations. The results show: (1) the effects of endogenous proteinases on membrane proteins derived from red cells stored under blood bank conditions; (2) a decrease of proteolytic effects in ghosts derived from red cells which have been submitted to a longer storage; (3) a relevant influence of the red cell resuspending medium before lysis on the time-dependent onset and exhaustion of proteolysis in ghosts. The presence of increased proteolysis in ghosts could be regarded as a marker of molecular lesions induced in red cells by storage under blood bank conditions.

Normal fibronectin levels after surgical treatment of portal hypertension in liver cirrhosis.

We found a significantly higher plasma fibronectin concentration in a group of nine cirrhotic patients who underwent surgical treatment for portal hypertension (either shunting and non shunting procedures) when compared to twenty non operated patients. Significantly shorter prothrombin time and activated partial thromboplastin time in the operated patients were found as well. These results might be related to an increased breakdown of fibronectin during consumption coagulopathy taking place in the extended collaterals and reversed in part by surgical treatment of portal hypertension complicating liver cirrhosis.

Time-related shape control modifications during erythrocyte storage with additive solutions.

To obtain more detailed information on the reversibility of shape alterations in blood bank stored erythrocytes, we have studied shape recovery after chemical crenation and rheological properties in 8 PAGGS-sorbitol preserved erythrocyte concentrates during a five week storage period under blood bank conditions. Our results show that red cell capability to regain a normal discoid shape after chemical crenation decreases during storage but is not lost over a five week period. Moreover there is a significant but weak correlation between red cell ATP content and both shape recovery capability and viscosity. Our results confirm suspicious that red cell shape perturbations following blood bank storage are widely reversible. Two different mechanisms may be involved in reducing shape recovery capability during storage, namely an ATP-dependent mechanism and an energy-independent one. The energy dependent mechanism may be preserved by the previous addition of solutions which maintain higher energy levels during storage.