Antithrombin-III-Hamilton: a gene with a point mutation (guanine to adenine) in codon 382 causing impaired serine protease reactivity

Antithrombin-III-Hamilton is a structural mutant of antithrombin III with defective serine protease reactivity, demonstrable in three members of a French Canadian family. The propositus, a 54-year-old man with a history of recurrent thromboembolic events, and his two asymptomatic grown children are heterozygous for the mutant antithrombin III gene. In all three individuals, the immunoreactive antithrombin III level is normal, while the antithrombin and antifactor Xa activity is approximately 50% of the control value. Two dimensional immunoelectrophoresis of antithrombin-III-Hamilton in the presence of heparin is normal. Purified antithrombin-III-Hamilton did not form thrombin-antithrombin III complex when incubated with thrombin for up to 30 minutes. The normal and mutant antithrombin III alleles of the propositus could be distinguished by linkage to Pstl restriction fragment length polymorphisms (RFLP). Genomic DNA from the propositus was cloned into EMBL 3 phage vectors and two clones containing nearly complete copies of the antithrombin-III-Hamilton allele were identified. Exon 6 of both clones was subcloned into M13 phage vector and sequenced, revealing a G----A point mutation in the first base of codon 382. Codon 382 codes for alanine in the normal allele and for threonine in the antithrombin-III-Hamilton allele. Alanine-382, 12 residues from the reactive center, is a highly conserved amino acid in the family of serine protease inhibitors known as the serpins. We postulate that, as a result of the substitution of threonine for alanine in antithrombin-III-Hamilton, either the tertiary structure or the hydrophobicity of the thrombin-binding region is altered, causing aberrant conformation of the Arg-393-Ser-394 bond at the reactive center impairing the interaction between antithrombin-III-Hamilton and the activated serine proteases.     

B cell lymphoma and myeloma in murine Gaucher's disease

Multiple myeloma and B cell lymphoma are leading causes of death in Gaucher's disease but the nature of the stimulus driving the often noted clonal expansion of immunoglobulin‐secreting B cells and cognate lymphoid malignancy is unknown. We investigated the long‐term development of B cell malignancies in an authentic model of non‐neuronopathic Gaucher's disease in mice: selective deficiency of β‐glucocerebrosidase in haematopoietic cells [Gba^{tm1Karl/tm1Karl}Tg(Mx1‐cre)1Cgn/0, with excision of exons 9–11 of the murine GBA1 gene, is induced by poly[I:C]. Mice with Gaucher's disease showed visceral storage of β‐glucosylceramide and greatly elevated plasma β‐glucosylsphingosine [median 57.9 (range 19.8–159) nm; n = 39] compared with control mice from the same strain [median 0.56 (range 0.04–1.38) nm; n = 29] (p < 0.0001). Sporadic fatal B cell lymphomas developed in 11 of 21 GD mice (6–24 months) but only two of eight control animals developed tumours by age 24 months. Unexpectedly, most mice with overt lymphoma had absent or few Gaucher cells but local inflammatory macrophages were present. Eleven of 39 of Gaucher mice developed monoclonal gammopathy, but in the control group only one animal of 25 had clonal immunoglobulin abnormalities. Seven of 10 of the B cell lymphomas were found to secrete a monoclonal paraprotein and the lymphomas stained intensely for pan‐B cell markers; reactive T lymphocytes were also present in tumour tissue. In the Gaucher mouse strain, it was notable that, as in patients with this disease, CD138⁺ plasma cells frequently surrounded splenic macrophages engorged with glycosphingolipid. Our strain of mice, with inducible deficiency of β‐glucocerebrosidase in haematopoietic cells and a high frequency of sporadic lethal B cell malignancies, faithfully recapitulates human Gaucher's disease: it serves as a tractable model to investigate the putative role of bioactive sphingolipids in the control of B cell proliferation and the pathogenesis of myelomatosis—the most prevalent human cancer associated with this disorder. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Correlations among improvements in urgency urinary incontinence, health-related quality of life, and perception of bladder-related problems in incontinent subjects with overactive bladder treated with tolterodine or placebo

Background  

Previous studies demonstrate that tolterodine extended release (ER) significantly improves urgency urinary incontinence (UUI) episodes. Instruments that measure patient-reported outcomes (PROs) provide additional information that is valuable for assessing whether clinical improvements are meaningful to the patient. This study determined the correlation of changes in bladder diary variables and other PROs in subjects with overactive bladder (OAB).     

Genetic diversity of hepatitis A virus in Siberia

The nucleotide sequences of a region of VP1/2A genes of a large group of hepatitis A virus (HAV) isolates circulating in Siberia (the Altai Territory, the Irkutsk and Novosibirsk Regions) were determined. Comparison of these sequences with those of prototype HAV of genotypes IA, IB, and IIA revealed their high similarity to prototype genotype IA strains. The above domains were shown to contain the types of viruses, which were close to both the European subtypes of HAV genotypes IA (78.3%) and the Far Eastern subtypes of this genotype (21.7%). The similar comparison of the derived amino acid sequences suggests that VP1 and 2A contains the amino acid substitutions that are typical of this geographical region.     

Comparison of milk and maize based diets in kwashiorkor

The dual sugar test of intestinal permeability is a reliable non-invasive way of assessing the response of the small intestinal mucosa to nutritional rehabilitation. AIM: To compare a local mix of maize-soya-egg to the standard milk diet in the treatment of kwashiorkor. DESIGN: The diets were alternated three monthly in the sequence milk-maize-milk. There were a total of 533 kwashiorkor admissions of at least five days during the study who received either milk or maize. Intestinal permeability was assessed at weekly intervals by the lactulose-rhamnose test in 100 kwashiorkor cases, including 55 on milk and 45 on the maize diet. RESULTS: Permeability ratios (95% confidence interval) on the milk diet improved by a mean of 6.4 (1.7 to 11.1) compared with -6.8 (-16.8 to 5.0) in the maize group. The improved permeability on milk occurred despite more diarrhoea, which constituted 34.8% of hospital days (29.8 to 39.8) compared with 24.3% (17.8 to 30.8) in the maize group. Case fatality rates for all 533 kwashiorkor admissions were 13.6% v 20.9%, respectively, giving a relative risk of death in the maize group of 1.54 (1.04 to 2.28). The maize group also had more clinical sepsis (60% v 31%) and less weight gain (2.9 v 4.4 g/kg/day) than the milk group. IMPLICATIONS: Milk is superior to a local maize based diet in the treatment of kwashiorkor in terms of mortality, weight gain, clinical sepsis, and improvement in intestinal permeability.