The ‘mirrored’ Bennett fracture of the base of the fifth metacarpal

Fractures of the base of the metacarpals are usually treated conservatively. The intra-articular fracture of the base of the first metacarpal (‘Bennett fracture’) is an exception to this rule because inadequate repositioning and fixation of the dislocated radial fragment lead to permanent deformity of the joint and subsequent degenerative joint disease. The dislocated intra-articular fracture of the base of the fifth metacarpal is similar to a Bennett fracture in many aspects. Repositioning of this ‘mirrored’ Bennett fracture cannot be guaranteed by a plaster cast. Inadequate repositioning will lead to pain, reduced strength and early degenerative joint disease. We present six patients with dislocated intra-articular fractures of the base of the fifth metacarpal to illustrate the necessity of surgical reduction and fixation. Received: 20 June 1999     

Induction of experimental autoimmune arthritis by a public epitope of the T cell receptor variable alpha domain of an arthritogenic T cell clone

T cell receptor (TCR) peptide immunizations have been demonstrated to protect against experimental autoimmune diseases. These findings have led to clinical trials employing TCR peptides in multiple sclerosis and rheumatoid arthritis patients. Previously, we identified a strongly immunogenic region of the TCR alpha chain of an arthritogenic T cell clone (AV11 66-80). In this report, we show that rats immunized with AV11 66-80 developed arthritis with clinical symptoms and histology similar to adjuvant arthritis (AA). Transfer of this disease into naive rats using AV11 66-80-specific T cells proved the T cell-mediated character of the disease. The AV11 66-80 arthritic rats developed resistance to Mycobacterium tuberculosis-induced AA, indicating that both forms of arthritis depended on similar regulatory mechanisms. This first demonstration of TCR peptide-induced arthritis, together with an earlier report on a polymorphism in this very same AV11 66-80 region involved in arthritis resistance in mice, suggests a central role of the public epitope AV11 66-80 in the control of autoimmune arthritis. Although TCR peptide immunizations can be exploited to prevent experimental autoimmunity, caution should be taken in the induction of TCR peptide-specific T cells for immunotherapy to avoid adverse effects as shown here.     

Effets tardifs des radiations ionisantes sur les tissus de la sphère otorhinolaryngologique

Numerous structures are included in the irradiated volume of patients presenting with head and neck cancer: skin, mucosa, bone, teeth, cartilage, muscles, salivary glands, etc. Curative intent treatment of such tumours requires aggressive approach which can lead to severe sequellae. These sequellae are in most cases dose-dependent and volume-dependent. However, an appropriate technique might decrease the severity of such sequellae. Details of these late changes are presented, including their pathophysiology, clinical syndromes, potential treatment, and prevention.     

Ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.     

The STR system in the human phenylalanine hydroxylase gene: true fragment length obtained with fluorescent labelled PCR primers

We present a simple, fast, non-radioactive method for the analysis of the polymorphic short tandem repeat (STR) system in the human phenylalanine hydroxylase gene. Previously, sizing of the STR marker involved radiolabelling of PCR amplified fragments and resolution on denaturing polyacrylamide gels using M13 sequencing ladder as a standard. However, this method consistently gave sizes 2 bp longer than the known sequence. The fluorescent method presented here employs internal lane standards and enables accurate sizing of the fragments. To avoid confusion, we suggest that the true fragment lengths are used as reference values in the future. The analysis of STR alleles is valuable for population genetic studies and for targeted mutation screening in phenylketonuria (PKU). It can replace RFLP-based haplotype analysis for carrier detection, and we report its use for prenatal diagnosis in a Northern Irish family with PKU. The analysis of 250 Northern Irish chromosomes, including 128 PKU alleles, showed no significant difference between normal and PKU alleles, with fragment lengths of 238 and 242 bp most common in both groups.     

Factor VIII-von Willebrand factor requires calcium for facilitation of platelet adherence

The role of divalent cations in platelet adherence to deendothelialized human arteries in flowing blood was investigated in an annular perfusion chamber. Spreading of platelets on the subendothelium was impaired below 30 microM of free Ca2+ ions (Ca2+). When Ca2+ was replaced by Mg2+, adherence was unchanged in perfusates without exogenous factor VIII-von Willebrand factor (FVIII-vWF), but the ability of FVIII-vWF to support platelet adherence was lost. Binding of FVIII-vWF to the vessel wall was independent of divalent cations, but bound FVIII-vWF was only able to mediate adherence after exposure to Ca2+. Pretreatment of FVIII-vWF with the calcium chelator EGTA (10 mM) resulted in loss of the ability to facilitate platelet adherence, while the ristocetin cofactor activity remained intact. Full restoration of the ability to mediate platelet adherence could only be obtained by prolonged dialysis against Ca2+ in the millimolar range. These data indicate that divalent cations have at least two separate roles to play in supporting platelet adherence: (1) platelet spreading on the subendothelium requires Ca2+ or Mg2+; (2) FVIII-vWF should be exposed to Ca2+ to obtain its optimal biologic activity in supporting platelet adherence.