Factors predicting the need for splenectomy in children with blunt splenic trauma.

BACKGROUND/PURPOSE: Non-operative management of blunt splenic trauma (BST) in children is the standard of care with a success rate of greater than 90%. This paper aims to determine the factors which could predict the need for operative intervention in children with BST. METHODS: Prospectively entered data of 69 children with BST, between 1997 and 2008, from a single tertiary level trauma centre, were retrospectively analysed. A radiologist blinded to the outcome reviewed all computed tomography scans retrospectively. RESULTS: Forty-two children had isolated BST (61%) and 27 children had associated injuries (39%). All except one survived the injury and non-operative treatment was successful in 91%. Six of the 69 children (9%) with BST underwent splenectomy. There was no independent correlation to age, gender, mechanism of injury (MOI), injury grade and the need for splenectomy, whereas haemodynamic instability within 6 h of injury defined as failed resuscitation had a 100% correlation. CONCLUSION: Haemodynamic instability, which failed to respond to resuscitation within 6 h, predicted the need for splenectomy in children with BST. Splenic injury grade assessed by computed tomography scan does not predict the need for splenectomy.

Engineered variants of human glutamic acid decarboxylase (GAD) and autoantibody epitope recognition.

Of the two homologous forms of glutamic acid decarboxylase, GAD65 and GAD67, only GAD65 is a common target of autoimmunity. Epitope profiles of autoantibodies to GAD65 (GADA) in 140 type 1 diabetes, adult-onset diabetes mellitus (AODM), and thyroid diseases (TD) were studied. Probes were GAD65, GAD65/67 hybrids (displaying separately GAD65 residues 1-95, 96-444, and 445-585), delta GAD65 (a truncated GAD65 spanning residues 69-585), and GAD67. delta GAD65 and GAD65 detected 137 and 125 positive patients, respectively. The hybrids reacted with 113 sera and in 3 cases disclosed cryptic epitopes. Eighteen patients reacted with GAD67, indicating GAD65-GAD67 cross-reactivity. Most patients recognized both middle and C-terminal epitopes, had low reactivity against N-terminal epitopes, and seldom displayed reactivity limited to the N or C terminus. Compared with type 1 and AODM, TD patients showed a greater prevalence of multiple reactivity and higher incidence of GAD67 positivity.

Replacement of methionine-161 with threonine eliminates a major by-product of human glutamate decarboxylase 65-kDa variant expression in Escherichia coli.

Most insulin-dependent diabetes mellitus patients gen-erate conformational autoantibodies to the islet-cell 65-kDa variant of human glutamate decarboxylase (GAD65), and several immunochemical tests for the early detection of type-1 diabetes rely on GAD65 antibody (GADA) assessment using properly folded recombinant GAD65 as the antigen. In addition, preventive therapies based on tolerization by GAD65 administration may be available in the near future. Therefore, there exists a strong interest in a facile and economically sound expression procedure for this antigen. Several attempts to produce, in native form, wild-type GAD65 in Escherichia coli have failed. However, this difficulty was recently surmounted in our laboratory by expressing GAD65 as a fusion protein with thioredoxin [Papouchado, Valdez, Ghiringhelli, Poskus and Ermácora (1997) Eur. J. Biochem. 246, 350-359]. In this work, a new GAD65 hybrid gene was prepared by joining engineered cDNA obtained from human and rat tissues. The new gene was modified additionally to finally code for human GAD65 with a single amino-acid substitution: Met-161-->Thr. This change impeded the co-expression of a 48-kDa by-product from an internal translation site. Also, a second 58-kDa by-product was identified as a GAD65 C-terminal proteolytic fragment that co-purifies with thioredoxin-M161T GAD65. The new GAD65 variant was expressed and easily purified, yielding an antigen that performed equally or better than wild-type GAD65 in the reference radiobinding assay for GADA. The procedure provides an inexpensive source of large amounts of fully active and immunochemically competent GAD65.