Mechanics of the anterior drawer and talar tilt tests: A cadaveric study of lateral ligament injuries of the ankle

We analyzed the changes in lateral ligament forces during anterior drawer and talar tilt testing and examined ankle joint motion during testing, following an isolated lesion of the anterior talofibular ligament (ATFL) or a combined lesion of the ATFL and calcaneofibular ligament (CFL). 8 cadaver specimens were held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantarflexion and supination-pronation) could be varied in a controlled manner. Ligament forces were measured with buckle transducers, and joint motion was measured with an instrumented spatial linkage. An anterior drawer test was performed using an 80 N anterior translating force, and a talar tilt test was performed using a 5.7 Nm supination torque with intact ligaments, after sectioning of the ATFL, and again after sectioning of the CFL. The tests were repeated at 10° dorsiflexion, neutral, and 10° and 20° plantarflexion. In the intact ankle, the largest increases in ATFL force were observed during testing in plantarflexion, whereas the largest increases in CFL force were observed in dorsiflexion. Isolated ATFL injury caused only small laxity changes, but a pronounced increase in laxity was observed after a combined CFL and ATFL injury.     

The use of post-embedding immunoelectron microscopy in the diagnosis of glomerular diseases. Comparison of immunoelectron microscopic and immunofluorescence studies.

Fifty renal biopsies were studied by immunoelectron microscopy after embedding in a partly hydrophilic polyacrylic resin (LR White). Immunofluorescence studies were carried out on frozen sections of parallel tissue samples. Polyacrylic embedding gave good preservation of the renal ultrastructure and precise localization of immunoglobulin and C3c antibodies within glomerular electron-dense deposits. Non-specific staining of plasma proteins within vascular lumina could easily be detected. There was good correlation between immunoelectron and immunofluorescence microscopy. Immunoelectron microscopy is a very sensitive method, which can detect small amounts of antigen. More cases were, however, positive by immunofluorescence than by immunoelectron microscopy. This discrepancy may be explained by difference in sample size, and by difference in resolution of morphological details (electron microscopy versus fluorescence microscopy).     

Dyssynchrony of segment shortening in the anterior wall of the feline left ventricle.

Non-uniformity of regional contraction may be both spatial and temporal. This study was undertaken to deal with the temporal aspects of shortening and to quantify non-uniformity with regard to timing. Nine cats were anaesthetized and artificially ventilated. Two pairs of ultrasonic crystals were situated in the anterior midwall of the left ventricle to measure regional shortening. One pair, longitudinal segment, was oriented to align with midwall fibres. The other pair, transverse segment, was placed perpendicular to the first one. Registrations in control state, during caval occlusion, and during aortic constriction were carried out with and without isoprenaline infusion. Cyclic events were analysed in terms of phase angle, 0-2 pi representing one heart cycle. Transverse segments showed marked shift of duration of shortening, from 1.19 pi +/- 0.06 pi (mean +/- SEM) in the control state to 0.40 pi +/- 0.14 pi during caval occlusion with isoprenaline infusion. Duration of shortening of longitudinal segments showed less prominent shift with mean values between 1.38 pi and 1.11 pi. Regional uniformity of timing, expressed as synchronization index, varied markedly with interventions (P less than 0.0005). Dyssynchrony was most prominent during caval occlusion with mean values less than 0.6. A simple model of force generation for the two segments visualizes that segment shortening of the transverse segment is of shorter duration than the longitudinal segment and a common mechanism for temporal and spatial non-uniformity within a region could be elaborated. This study quantifies both the time course of shortening and temporal non-uniformity of two cross-oriented segments within the same myocardial region.     

Histopathology training in Europe: a lesson for other specialties?

Critical shortages of trained histopathologists limit the capacity of cancer and other clinical services. A survey of histopathology training in 18 European countries conducted by the European Union of Medical Specialists Section of Pathology/European Board of Pathology revealed a considerable shortage of both trained and trainee histopathologists in several of the responding countries. Demographic data indicate a high preponderance of trained histopathologists over 55 years of age and a notable proportion of part-time personnel. Although the training capacity in some countries has been increased, the immediate future of histopathology and the clinical services dependent on the specialty is worrisome. The histopathology workload is growing, and, in some countries, recruitment of trainees is insufficient for future needs. To avert the serious consequences for dependent clinical specialties and their patients, there should be a concerted European action to promote and expand histopathology training.     

High levels of Lp(a) lipoprotein in a family ith cases of severe pre-eclampsia

We report a family with two cases of severe pre-eclampsia/eclampsia in which very high levels of Lp(a) lipoprotein were found. The serum level of Lp(a) lipoprotein is genetically determined and the Lp(a) apolipoprotein has a close homology to plasminogen. Very high levels of Lp(a) lipoprotein might interfere with the fibrinolytic/thrombolytic process in man. A previous report suggested that a high maternal serum Lp(a) lipoprotein level can cause fetal growth retardation, and it is proposed that very high levels might lead to increased deposition of fibrin in the uterine spiral arteries in pregnancy, which is central in the pathogenesis of pre-eclampsia. If confirmed, a very high Lp(a) lipoprotein level could be one risk factor for pre-eclampsia that is genetically determined.     

The effect of AVP‐V1 receptor stimulation on local GFR in the rat kidney

Aim: Arginine vasopressin (AVP) might influence urinary concentration ability by altering the intrarenal distribution of glomerular filtration rate (GFR). Methods: To study this possibility we have measured the intracortical distribution of GFR following acute AVP‐V₁ receptor stimulation in anaesthetized female Sprague–Dawley (SPD) rats during euvolemia and water diuresis by the aprotinin method, allowing two consecutive measurements of zonal GFR in the same kidney. Results: Acute i.v. bolus injection of 50 ng V₁ receptor agonist ([Phe², Ile³, Orn⁸]‐vasopressin) followed by a continuous infusion of 5 ng min^?1 in euvolemic rats reduced GFR by 25% in outer cortex (OC), 20% in middle cortex (MC) and 19% in inner cortex (IC) relative to vehicle infusion (all P < 0.05). In water diuretic rats V₁ receptor agonist reduced GFR by 22% in OC, 10% in MC and 11% in IC relative to vehicle infusion (P < 0.05). GFR decreased slightly more in OC than in MC and IC in both euvolemic and water diuretic rats (P < 0.05) indicating a distribution of GFR towards MC and IC. Acute infusion of the selective non‐peptide V₁ receptor antagonist OPC‐21268 in euvolemic rats reduced GFR by 14% in OC, 13% in MC and 11% in IC relative to vehicle infusion (P < 0.05), with no significant difference between the layers. Conclusions: The change in distribution of GFR not only between OC and IC, but also between OC and MC suggests that the afferent/efferent arterioles and not the medullary vasa recta is the main site of resistance change. We conclude that acute i.v. infusion of V₁ receptor agonist in high doses reduces GFR more in superficial than in deep cortex in both euvolemic and water diuretic rats and that this may be of some importance for water conservation, adding to the V₂‐ receptor effect on water permeability of the collecting ducts.     

Fibre orientation in the left ventricle and its influence on local pressure-length loop analysis in cats

Deviation from local fibre orientation may seriously affect quantification of myocardial segment work, as measured by implanted ultrasound crystals. Crystal pairs were positioned in mid-wall layers with known directions to the long axis of the heart. One transmitter and four receiving crystals covered a sector on the anterior ventricular wall of 100 degrees. The results show a strong influence of alignment to fibre direction on the pressure-length loop area; the relation followed a cos2 psi function where psi denotes the angle between the crystal pair direction and fibre direction established by microscopy. The angle between the mid-wall muscle fibres on the anterior aspect of the left ventricle and the long axis of the heart varied between 62 degrees and 90 degrees with a mean value of 76 degrees. This study shows that pressure-length loop quantitation depends strongly on crystal alignment to cardiac muscle fibres through which the ultrasound passes.     

IgG subclass antibodies to serogroup B meningococcal outer membrane antigens following infection and vaccination

IgG and IgG subclass antibodies to the outer membrane antigens from Neisseria meningitidis (serogroup B, serotype 15:P1.16) were quantitated by an enzyme-linked immunosorbent assay (ELISA) in sera from 40 patients with group B:15:P1.16 meningococcal disease and 24 volunteers immunized with a serotype 15:P1.16 outer membrane vesicle vaccine. A second injection was given 6 weeks after the first immunization. Patient sera obtained two and six weeks after onset of the disease had significantly higher levels of total IgG, IgG1, IgG2, and IgG3 antibodies to the outer membrane antigens than acute sera, convalescent sera from patients with systemic non-meningococcal bacterial infections and sera from healthy controls. The levels of total IgG and IgG1 remained high one and three years later. Sera from the vaccinees showed high levels of total IgG and IgG1 6, 12 and 26 weeks after the first immunization and high levels of IgG3 6 weeks after the second immunization. No increase of IgG2 or IgG4 levels was observed in the postimmunization sera. Immunoblotting of three convalescent sera demonstrated individual patterns of IgG subclass binding to various outer membrane antigens with most distinct binding of IgG1 and IgG3 antibodies to the class I protein, the H.8 lipoprotein and the lipopolysaccharide. Since IgG1 and IgG3 are the most effective antibodies for complement activation and phagocytosis, group B meningococcal disease and immunization with the serotype 15:P1.16 outer membrane vesicle vaccine stimulate production of those IgG subclasses which have the strongest opsonic and bactericidal activity.     

Residual effects of prior exercise and recovery on subsequent exercise-induced metabolic responses

Abstract Data on the metabolic responses to repeated endurance exercise sessions are limited. Thus, the aims of this study were to examine (1) the impact of prior exercise on metabolic responses to a subsequent exercise session and (2) the effect of different recovery periods between two daily exercise sessions on metabolic responses to the second bout of exercise. Nine male elite athletes participated in four 25-h trials: one bout of exercise (ONE), two bouts of exercise separated by 3 h of rest and one meal (SHORT), two bouts of exercise separated by 6 h of rest and two meals (LONG), and a trial with no exercise (REST). All exercise bouts consisted of 10 min cycling at 50% followed by 65 min at 75% of maximal O₂ uptake. Compared to no prior exercise (ONE), a previous bout of exercise (SHORT) was followed by higher mean O₂ uptake, heart rate (HR), rectal temperature (T_R), excess post-exercise oxygen consumption and lower respiratory exchange ratio (R) during and after a similar exercise session 3 h later. A longer rest interval between the two exercise bouts (6 h versus 3 h) and an additional meal resulted in a decrease in O₂ uptake, HR, T_R and an increase in R during the second bout of exercise, but no effects on post-exercise metabolism were found. Thus, augmented metabolic stress was observed when strenuous exercise was repeated after only 3 h of recovery, but this was attenuated when a longer recovery period including an additional meal was provided between the exercise sessions.