The experience with central venous implantable devices (portacaths) has been reviewed in children attending the Auckland Hospital Haemophilia Centre. Fourteen children had 23 portacaths inserted. Thirteen had severe Haemophilia A, of whom five had high responding inhibitors to factor VIII. All the children were HIV negative. Ages ranged from 4 months to 13 years at the time of initial placement and 12 were under 5 years. Indications for portacath placement included primary and secondary prophylaxis, induction of immune tolerance, prophylactic therapy post intracranial haemorrhage and poor venous access. Catheter-related infections occurred in 48% of cases. Staphylococcal species were the most common organisms isolated followed by gram-negative bacilli. 63% of the infections were successfully cleared with antibiotics. Haematoma formation occurred in 17% of catheters, primarily in patients who had high factor VIII inhibitor levels. Mechanical problems including blockage, leakage and extrusion of the portacath occurred less frequently (13%). The significant rate of infection in this immunocompetent population is consistent with other reports. Despite the obvious benefits of portacaths this complication is potentially serious and causes appreciable morbidity. In contrast, bleeding complication rates were relatively low.

Chromosome analyses of bone marrow cells prepared by the direct method were carried out on 32 male patients, who had no primary haematological disease. One patient was found to have a pericentric inversion of the Y chromosome, which was also present in a skin fibroblast culture and in a lymphocyte culture. Three cases were found to have a high percentage of bone marrow cells with a 45,X chromosome constitution and one case had a 45,X?Yor Gcell line. The high degree ofaneuploidy was not found on examination of cells from leucocyte cultures. This observation is discussed in relation with other similar findings in patients with haematological diseases. The remaining 27 patients had a normal male karyo-

SummaryThe Gray platelet syndrome is a rare disorder characterised by the absence of platelet a-granules and their contents. We describe a new patient and the effects of infusions of l-deainino-8-aiginine vasopressin (DDAVP). The patient had a prolonged skin bleeding time and his platelets had reduced numbers of a-granules, increased vacuolation and reduced retention on glass beads. Flatelet von Willebrand factor antigen (vWf:Ag) was undetectable and levels of platelet fibrinogen, p-thioniboglobulin, platelet factor 4 and thrombospondin were reduced. All tests of plasma coagulation factors were normal, including Factor VIII (F. VIII: C), vWf: Ag, ristocetin cofactor (R: CoF) and botrocetin cofactor. Platelet ATP, ADP, platelet albumin, surface membrane glycoproteins and 14C-serotonin uptake were also normal. Infusions of DDAVP increased plasma F.VIII:C, vWf:Ag and R.CoF and sliuitened the bleeding time un two occasions. This suggests that DDAVP shortens the bleeding time by releasing vWf: Ag and/or other proteins from cellular storage sites other than the platelet.

Many patients in Australia and New Zealand with inhibitors to human factor VIII presently show a low or absent level of cross-reactivity to porcine factor VIII. These may respond to treatment with this concentrate at least in the short term. There remains a group of patients with high cross-reactivity who will respond only to recombinant factor VIIa or prothrombin complex concentrates.

Haemophilia B Leyden is characterized by severe factor IX deficiency during childhood with partial resolution at puberty or following the administration of anabolic steroids. The disorder has recently been associated with point mutations in the putative factor IX promoter region, which contains an imperfect direct repeat spanning a possible start site of transcription. We have identified a T to C transition at position +8 in the promoter region of a patient with the haemophilia B Leyden phenotype. A mutation at this site has not been previously reported and occurs within the repeat consensus sequence in the transcribed but untranslated portion of the gene. There is no family history of haemophilia and sequence analysis of his mother and other family members indicates that the mutation has arisen de novo in this patient. This observation provides further support for a causal relationship between point mutations in the presumptive promoter region of the factor IX gene and the Leyden phenotype.

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Cytogenetic studies of marrow cell lines were done in 10 cases of erythroleukemia and in 6 cases of potentially preleukemic refractory megaloblastic anemia. Abnormalities consisting of aneuploidy, increased polyploidy and chromosome breakage were found in 9 cases, 6 in the erythroleukemia group and 3 in the refractory anemia group. Observations in these cases support the concept that erythroleukemia is a clinical variant of acute granulocytic leukemia. They also indicate that marrow chromosome analysis can assist in the diagnosis of cases where leukemia is suspected but not clinically proven.

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