Precise carrier diagnosis in families with haemophilia A: use of conformation sensitive gel electrophoresis for mutation screening and polymorphism analysis

Causative mutations in the factor VIII gene of seven unrelated patients with severe haemophilia A were identified using the mutation screening procedure conformation sensitive gel electrophoresis (1) and characterised by direct sequencing. Female family members of all patients had requested either carrier status determination or prenatal diagnosis. However, lack of the factor VIII gene inversion, a prior family history or informative polymorphisms prevented diagnosis in these families. Identification of a mutation in each family enabled female carrier status to be determined in all cases. Six mutations were previously unreported. One Afro-Caribbean patient had two sequence changes; A670 2G and A6769G. The latter, resulting in Met2238Val and previously reported as a FVIII mutation, was shown to be polymorphic with a 42% heterozygosity rate in an Afro-Caribbean population. Conformation sensitive gel electrophoresis was found to be technically simple and efficient at locating previously unknown FVIII gene mutations.

Parvovirus-induced pancytopenia in a child with acquired haemolytic anaemia

A 14-year-old boy, with acquired haemolytic anaemia secondary to paravalvular leak from a prosthetic aortic valve, presented with severe pancytopenia. Subsequent investigation showed serological evidence of recent parvovirus B19 infection. The patient required transfusion and subsequently improved rapidly, with maintenance of pre-infective haemoglobin levels. To our knowledge this is the first reported case in which infection with parvovirus has caused pancytopenia in an acquired chronic mechanical haemolytic anaemia.

The effect of a monoclonal antibody to tumor necrosis factor on survival from childhood cerebral malaria

Tumor necrosis factor (TNF) is thought to play a key role in the pathogenesis of cerebral malaria. A double-blind, placebo-controlled trial of an anti-TNF monoclonal antibody (B-C7) comprised 610 Gambian children with cerebral malaria, with mortality and residual neurologic sequelae as primary study end points. Sixty (19.9%) of 302 children who received B-C7 died compared with 64 (20.8%) of 308 children who received placebo (adjusted odds ratio [OR], 0.90; 95% confidence interval [CI], 0.57-1.42). Residual neurologic sequelae were detected in 15 (6.8%) of 221 survivors from the B-C7 group and in 5 (2.2%) of 225 survivors of the placebo group (adjusted OR, 3.35; 95% CI, 1.08-10.4). The monoclonal antibody used in this study did not improve survival in cerebral malaria and was associated with a significant increase in neurologic sequelae. A possible explanation of the latter observation is that the antibody acts to retain TNF within the circulation and thereby prolongs its effects on vascular endothelium.

Efficacy of recombinant interferon-alpha (rIFN-alpha) in polycythaemia vera: a study of 17 patients and an analysis of published data

The efficacy and tolerability of rIFN-alpha has been evaluated in 17 selected patients with symptomatic polycythaemia vera, diagnosed according to the PRV Study Group criteria. Complete disease control (CR) was achieved, after 1-12 months, in nine patients, with partial control in a further five cases. Three patients failed to respond. Pruritus significantly improved in 83% (10/12) of cases, following 1-28 weeks of treatment. Six patients (35%), however, were unable to tolerate rIFN-alpha, on account of weight loss, myalgia and mental changes. Overall, alpha-interferon therapy significantly improved venesection requirements, MCV and PCV values, platelet counts, pruritus scores and the degree of splenomegaly. Analysis of pooled published data (100 evaluable patients, including the present study) revealed an overall CR of 60%, a PR of 27%, and a failure rate of 13%. Significant pruritus control (> 50% improvement) occurred in 77% of cases. rIFN-alpha appears to be an effective therapy for PV-associated myeloproliferation and/or pruritus, although side-effects remain a concern. Long-term studies are now indicated to determine if the natural history of the disease is altered, in particular whether the incidence of myelofibrosis and/or leukaemic transformation is reduced.

Hepatitis C virus infection in multi-transfused children with haematological malignancy

Transmission of hepatitis C virus (HCV) is an important hazard of blood transfusion and may result in chronic liver disease. 98 children from Nottingham and Sheffield with haematological malignancies were studied to determine the prevalence of HCV infection by enzyme immunoassay and RT/PCR techniques. The children had been exposed to up to 184 donors through red cell and platelet transfusion, the majority prior to routine testing for HCV infection in blood donors. Only one sample showed evidence of HCV infection being both ELISA and RT/PCR positive. None of the samples taken since donor screening were positive. This provides reassurance as to the low rate of HCV acquisition in multi-transfused patients in this part of the U.K. compared to other parts of the world.

Effect of age upon the induction and maintenance of anticoagulation with warfarin

We aimed to examine the effect of age upon the control of anticoagulation with warfarin in ordinary clinical practice, using a retrospective examination of routine anticoagulation clinic records from the University Hospital, Nottingham. Considerable over-anticoagulation (international normalisation ratio (INR) > 6.0) during induction occurred in 54 (11%) of 495 patients and was more likely in older patients (p < 0.05). Lesser degrees of over-anticoagulation during induction (INR > 4.0) were also more common in older patients, occurring in 58% of those aged 75 or above. Loading doses of warfarin were not reduced in older patients. INR in the maintenance phase rose with age (p < 0.001) despite lower maintenance doses of warfarin (p < 0.001). An INR > 6.0 in the maintenance phase was noted in 24 (3%) of 739 patients and again was more likely in older patients (p < 0.05). Patients using ambulance transport to the clinic were older than those who did not (p < 0.01) and those aged over 75 had shorter intervals between clinic visits (p < 0.01). We conclude that doctors using warfarin therapy do not take sufficient account of the increased sensitivity of older people to warfarin. Hospital anticoagulant policies need implementation and evaluation.

Bone marrow and serum connective tissue polypeptides in idiopathic myelofibrosis

The distribution of collagen type VI and tenascin has been determined in both normal and myelofibrotic bone marrow by immunohistological techniques. In normal sections positivity was demonstrated in the periosteum (collagen type VI and tenascin) and in the walls of small blood vessels (tenascin). In contrast, myelofibrotic bone marrow showed an increased deposition of both proteins, especially collagen type VI, although this increase was restricted to the later fibrotic stages of the disease. Serum concentrations of collagen type I (PICP), collagen type III (PIIIP) and laminin (laminin P1) related polypeptides were determined in a further 26 patients. PIIIP levels were significantly raised, in contrast to PICP and laminin P1 concentrations. All three markers, however, were significantly elevated in patients with active/transforming disease. Laminin P1 and PICP levels showed a strong correlation, indicating a relationship between basement membrane and interstitial collagen metabolism, although they do not appear to offer any advantage over PIIIP for the monitoring of disease activity.

Comparison of capillary whole blood, venous whole blood, and plasma concentrations of mefloquine, halofantrine, and desbutyl-halofantrine measured by high-performance liquid chromatography

Whole blood mefloquine, halofantrine, and desbutyl-halofantrine concentrations were measured by high-performance liquid chromatography in capillary blood, venous blood, and venous plasma samples from patients along the Thai/Burmese border with falciparum malaria who were treated with either mefloquine (25 mg/kg) or halofantrine (24 mg/kg or 72 mg/kg). The limits of detection for mefloquine, halofantrine, and desbutyl-halofantrine were 50, 15, and 10 ng/ml, respectively, with 200 microliters whole blood samples. There was a good linear correlation (r > 0.9) between capillary and venous blood and between whole blood and plasma for all three compounds. Mefloquine concentrations in venous and capillary blood were very similar (mean ratio 1.02, 95% confidence intervals [CI] 0.95-1.09, n = 60), but were 1.15 times higher (95% CI 1.03-1.29) in whole blood than in plasma (n = 22). The halofantrine and desbutyl-halofantrine concentrations were 1.27 (1.12-1.45, n = 23) and 1.34 (1.16-1.55, n = 24) times higher in venous compared to capillary blood, while halofantrine but not desbutyl-halofantrine concentrations were lower in whole blood than in plasma (mean ratios: halofantrine: 0.83 [0.72, 0.94], n = 39 and desbutyl-halofantrine: 1.05 [0.96-1.15], n = 41). Measurement of mefloquine, halofantrine, or desbutyl-halofantrine in capillary blood is an accurate and practical alternative to venous blood sampling, and is particularly useful for sampling with children, and under field conditions when technical facilities are limited.

Protein C, antithrombin III and plasminogen: effect of age, sex and blood group

We conducted a cross-sectional study of antithrombin III (ATIII), protein C (PC) and plasminogen (Plg) concentrations in a population of healthy plasma donors in the Trent Region. The distribution of values for protein C was log normal whereas for ATIII and Plg the distributions were positively skewed and differed significantly from normal and log normal. Males had higher antithrombin III concentrations (mean 1.10 iu/ml, range 0.72-1.65) than females (mean 1.07 iu/ml, range 0.75-1.69) (P = 0.001) and levels increased with age in women. Younger women aged 25-34 had significantly lower plasma concentrations of ATIII compared to males of similar age. For protein C, concentrations were higher in males (mean 1.07 u/ml, range 0.37-2.11) than in females (mean 1.01 u/ml, range 0.59-1.61) (P < 0.001) and levels increased with age in both sexes P < 0.001). In women, a novel difference in protein C concentration between ABO blood groups was noted. There was no significant difference in plasminogen concentration between males and females, and in women plasminogen decreased with age (r = -0.205, P < 0.001). We conclude that these variations in ATIII and protein C with age and sex are important considerations in the determination of reference ranges for these proteins.

Single day mefloquine-artesunate combination in the treatment of multi-drug resistant falciparum malaria

The therapeutic efficacy and toxicity of a combination of low dose mefloquine (15 mg/kg) plus artesunate 10 mg/kg in one day (MA) was compared with the currently used regimen of high dose mefloquine (25 mg/kg) (MQ) in 552 patients with uncomplicated falciparum malaria in an area of multi-drug resistance on the Thai-Burmese border. MA gave faster clinical and parasitological responses and prevented early treatment failure; 15 patients in the MQ group (6%) were early failures (< 9 d) compared with none receiving MA (P = 0.0001). Overall failure rates by day 28 were 19% in the MA group and 24% in with MQ group (relative risk (RR) = 0.78, 95% confidence interval (CI) 0.54-1.12). In the subgroup of patients who required re-treatment, MA proved significantly more effective than MQ; failure rates were 25% and 52% respectively (RR = 0.49, 95% CI = 0.29-0.83). Treatment failures were associated with mefloquine treatment in the previous month (RR = 1.72, 95% CI = 1.09-2.70) and diarrhoea (RR = 1.55, 95% CI = 1.05-2.28). Gastrointestinal side-effects and dizziness were more likely in the MQ group. There was no evident adverse effect associated with artesunate. A single day's treatment with artesunate augments the antimalarial efficacy of mefloquine.

Interaction of hepatitis B and hepatitis C infection in haemophilia

The management of haemophilia has been greatly complicated by the clinical sequelae of viral infection acquired through contaminated blood products. Many haemophiliacs have been infected by several viruses and the interaction between these viruses may be complex. In a cohort of 42 anti-HCV positive haemophiliacs, five were also found to be positive for HBsAg. All five were HCV reverse transcriptase/PCR negative compared to the 4/37 (11%) anti-HCV positive haemophiliacs who were HBsAg negative (P = 0.0001). We have identified a striking interaction between hepatitis C (HCV) and hepatitis B (HBV) in haemophiliacs co-infected by these agents, suggestive of the phenomenon of viral interference.

Bed nets for the prevention of malaria and anaemia in pregnancy

A prospective comparison of the antimalarial efficacy of bed nets was conducted with 341 pregnant women living in a mesoendemic malarious area of the Thai-Burmese border. Women in 3 adjacent study sites were allocated at random to receive either a single size permethrin-impregnated bed net (PIB), a non-impregnated bed net (NIB), or to a control group who used either their own family size non-impregnated bed net (FNIB) or no net. In one study site, but not the other 2, PIB significantly reduced parasite densities and, together with FNIB, reduced the incidence of malaria in pregnancy from 56% to 33% (relative risk = 1.67, confidence interval = 1.07-2.61, P = 0.03, allowing for parity). Anaemia proved a more sensitive marker of bed net antimalarial efficacy than parasite rates. The incidence of anaemia (haematocrit < 30%) at all study sites was significantly lower at delivery in the PIB (27%) and FNIB groups (21%) than in the NIB group (41%) or those using no net (56%). This suggests that a significant proportion of the malaria in pregnancy in this mesoendemic area was sub-patent. Both patent Plasmodium falciparum parasitaemia and anaemia were associated with a reduction in birth weight. Infant mortality was high (16%) and strongly associated with prematurity, low birth weight and maternal anaemia. PIB were well tolerated and had no apparent adverse effect on the pregnancy or infant development. Although the overall effect of bed nets on patent parasitaemia was marginal, they were associated with a significant reduction in maternal malaria-associated anaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Halofantrine versus mefloquine in treatment of multidrug-resistant falciparum malaria

The continuing spread of multidrug resistance in Plasmodium falciparum malaria makes the search for alternative treatments ever more urgent. We have investigated the relative efficacy of halofantrine and mefloquine in two paired randomised trials on the Thai-Burmese border, a multidrug-resistant area. In the first trial, 198 patients with acute uncomplicated falciparum malaria were randomly assigned either the standard halofantrine regimen (24 mg/kg) or mefloquine (25 mg/kg). The cumulative failure rates by day 28 were 35% with halofantrine and 10% with mefloquine (p = 0.0002). In the second study of 437 patients, a higher dose of halofantrine (8 mg/kg every 8 h for 3 days = 72 mg/kg) was both more effective and better tolerated than mefloquine 25 mg/kg; the failure rates were 3% and 8% (p = 0.03), respectively, or 1% vs 6% after adjustment for possible reinfections (p = 0.009). The rate of failure was higher after retreatment than after primary treatment in all study groups. Halofantrine 72 mg/kg was especially effective in the retreatment of these recrudescent infections; the failure rate was 44% with mefloquine and 15% with high-dose halofantrine (relative risk 3.0 [95% CI 1.2-7.3], p = 0.008). Thus, high-dose halofantrine is better tolerated and more effective than mefloquine for the treatment of uncomplicated falciparum malaria in this area. However, evidence of possible cardiotoxicity will need to be investigated fully before a role can be established for halofantrine in the treatment of multidrug-resistant malaria.

Characterization of an acute micromegakaryocytic leukaemia: evidence for the pathogenesis of myelofibrosis

The current hypothesis for the pathogenesis of myelofibrosis involves the intramedullary release of growth factors from defective or abnormal megakaryocytes. We describe a case of an acute micromegakaryocytic leukaemia, in a patient with chronic myelofibrosis, that provides additional evidence for this concept. The micromegakaryocytes, which reached 223 x 10(9)/l, were characterized morphologically by both light and electron microscopy, immunocytochemically and by platelet peroxidase activity. The cells were shown to have a mature cytoplasm, containing alpha granules and the associated proteins; vWF:Ag, fibrinogen, fibronectin and protein S. DNA analysis, by both a Seescan Solitaire Plus image analysis system and flow cytometry, revealed nuclear immaturity, with 92% of cells being diploid. Serum markers of connective tissue synthesis, namely carboxy terminal peptide of procollagen I (PICP), procollagen terminal peptide III (PIIIP) and laminin all increased significantly following transformation and were associated with an increase in platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta). These observations support the current hypothesis for bone marrow fibrosis formation and provide, for the first time, a link between in vivo growth factor release, bone marrow stromal turnover and megakaryocyte mass. In addition, the release of biologically active TGF-beta may explain both the increased fibronectin and angiogenesis characteristic of myelofibrotic bone marrow.

Extrapulmonary lymphomatoid granulomatosis presenting as Pancoast's syndrome

We report the case of a 55 year old man who presented as Pancoast's syndrome associated with a left sided Horner's syndrome, a mass in the left supraclavicular fossa and marked weakness with wasting of the left arm consistent with a left sided brachial plexus lesion. Biopsy revealed the typical features of lymphomatoid granulomatosis. Neurological involvement is a rare presenting manifestation of this uncommon disease. Lymphomatoid granulomatosis should be considered as a rare but potentially treatable cause of Pancoast's syndrome.

Congenital sideroblastic anaemia in two girls

Transfusion dependent congenital sideroblastic anaemia occurred in infancy in two unrelated girls. One girl developed early organ failure which was not prevented by standard chelation treatment. The combination of modest iron burden and putative intrinsic mitochondrial dysfunction could have accounted for the clinical picture. The other girl remained well, receiving regular transfusion and standard chelation treatment. She had normal liver function and no other evidence of organ damage. The syndrome is unlikely to be due to extreme lyonisation in carriers of the usual X-linked condition. The contrasting clinical patterns seen in these two patients suggest that transfusion dependent congenital sideroblastic anaemia may comprise a heterogeneous group of disorders. It is suggested that such children be carefully monitored for evidence of increasing iron overload so that organ damage can be prevented.

Value of monoclonal anti-myeloperoxidase (MPO7) for diagnosing acute leukaemia

The expression of myeloperoxidase (MPO) was studied in 100 cases of acute leukaemia (83 with acute myeloid leukaemia (AML) and 17 acute lymphoblastic leukaemia (ALL) by both a conventional cytochemical method and the immunocytochemical antiperoxidase (APAAP) technique using the monoclonal antibody MPO7. In each case the staining was evaluated by light microscopical examination (percentage of positive cells). Of the 83 cases of AML, 78 (93.9%) were positive for MPO7 compared with 70 (84.3%) by cytochemistry. Antibodies against the myeloid markers CD13 and CD33 were positive in 71 (85.5%) and 70 (84.3%) cases, respectively. Importantly, all cases of ALL were negative for both MPO7 and cytochemical MPO staining even when they were positive for CD13 and CD33. These results indicate that the anti-myeloperoxidase antibody MPO7 is the most sensitive and specific reagent for the diagnosis of AML and should therefore be included in routine immunophenotyping panels.

Immunoblastic lymphoma presenting with syncope due to sinoatrial node disease

A 68 year old man presented with syncope associated with episodes of sinus arrest. He responded to insertion of a demand pacemaker. During investigation he was noted to have generalized lymphadenopathy and biopsy revealed that he had an immunoblastic lymphoma. Before further assessment could be made, he developed rapid atrial fibrillation, resistant to several anti-arrhythmic agents and died several days after admission. At autopsy a nodular plaque of lymphoma was found to overly the sinoatrial node which was markedly fibrosed with evidence of lymphomatous infiltration of the surrounding microvasculature.