Effectiveness of early orthodontic treatment with the Twin-block appliance: a multicenter, randomized, controlled trial. Part 1: Dental and skeletal effects.

This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant.     

A Truly Knotted Cord

Summary: A case of 4 true knots in an umbilical cord, which did not cause any detectable harm, is presented. Careful examination of the placenta, membranes and umbilical cord continues to be encouraged.     

Ontogeny and thymus-dependence of T cell surface antigens in Xenopus : flow cytometric studies on monoclonal antibody-stained thymus and spleen

Recently generated anti-Xenopus T cell monoclonal antibodies (mAbs) to the 120 kDA XTLA-1 determinant and against the putative CD5 and CD8 homologues, together with anti-IgM and anti-MHC class II mAbs, are used in dual colour flow cytometric experiments to characterize cell surface antigenic expression on lymphocytes in thymus and spleen of Xenopus laevis during larval and early adult life and also in metamorphosis-inhibited animals. Histological confirmation of T cell emergence early in larval ontogeny is supplied by cryostat sections stained for CD8. Five-day thymectomy i.e. prior to T-lineage cell differentiation in the thymus, abolishes T cell marker expression in the spleen for up to 1 year. Moreover, late larval (20 days) or early adult (3 months) thymectomy (i.e. removal after peripheralization of T cells has occurred) also leads to severe depletion of mAb-defined T cells in the spleen.     

Gastric outlet obstruction caused by traumatic pseudoaneurysm of superior mesenteric artery

Traumatic pseudoaneurysms of the superior mesenteric artery (SMA) are extremely rare. We describe two cases of posttraumatic proximal SMA pseudoaneurysms with symptoms of gastric outlet obstruction. Repair was accomplished by aorta-SMA bypass with saphenous vein. Injuries to the proximal SMA are easily missed at laparotomy, especially if intestinal ischemia or hematomas are absent. Recognition and repair are stressed to avoid the complications associated with pseudoaneurysm formation.     

Saphenous vein in situ bypass

Revascularization of the ischemic diabetic extremity presents a significant diagnostic and technical challenge. The in situ saphenous bypass provides a conduit that allows revascularization to arteries at the ankle and proximal foot. Evaluation of the distal circulation, the adequacy of the saphenous vein, and routine follow-up after bypass, along with the operative procedure, are described. Balloon inflow occlusion arteriography, duplex mapping of the saphenous vein, operative technique, and follow-up protocol are discussed.     

Mortality league tables: do they inform or mislead?

OBJECTIVE--To examine certain methodological issues related to the publication of mortality league tables, with particular reference to severity adjustment and sample size. DESIGN--Retrospective analysis of inpatient hospital records. SETTING--22 hospitals in North West Thames health region for the fiscal year 1992-3. SUBJECTS--All admissions with a principal diagnosis of aortic aneurysm, carcinoma of the colon, cervical cancer, cholecystectomy, fractured neck of femur, head injury, ischaemic heart disease, and peptic ulcer. MAIN MEASURES--In hospital mortality rates adjusted by disease severity and calculated on the basis of both admissions and episodes. RESULTS--The numbers of deaths from specific conditions were often small and the corresponding confidence intervals wide. Rankings of hospitals by death rate are sensitive to adjustment for severity of disease. There are some differences that cannot be explained using routine data. CONCLUSIONS--Comparison of crude death rates may be misleading. Some adjustment for differences in severity is possible, but current systems are unsatisfactory. Differences in death rates should be studied, but because of the scope for manipulating data, this should be undertaken in a collaborative rather than a confrontational way. Any decision to publish league tables of death rates will be on political rather than scientific grounds.