Signs of acute carpal instability associated with distal radial fracture

The posteroanterior and lateral wrist radiographs of 52 adults who sustained acute distal radial fractures were reviewed to determine the incidence of radiographic signs of concomitant acute scapholunate ligamentous injury. Three radiographic criteria, either separately or in concert, were used to identify scapholunate ligamentous injury. They are (a) scapholunate angle >60°; (b) widening of the scapholunate space >2 mm; and (c) the cortical ring sign (also called the scaphoid or signet ring sign). Thirty-six of 52 cases (69%; 95% confidence interval =52.1–82.2%) showed evidence of scapholunate ligamentous injury; 16 of 52 cases (31%; 95% confidence interval =16.8–46.6%) showed no evidence of scapholunate ligamentous injury. Statistical analysis suggests that a minimum of 52.1% of all adult distal radial fractures are associated with signs of concurrent acute scapholunate ligamentous injury. The analysis also suggests that independent variables such as age, gender, severity of radius fracture, or mechanism of injury do not significantly alter the incidence of associated carpal ligamentous instability. This study has established a greater than 52.1% incidence of radiographic signs of scapholunate instability in adults with acute distal radial fractures. It is incumbent upon radiologists to search for the signs of scapholunate dissociation in all adult cases of distal radius fracture, regardless of age, gender, severity of radius fracture, or mechanism of injury.     

DISSOCIATION,AGGREGATION OF SESAME α-GLOBULIN IN NONIONIC DETERGENT SOLUTION

Nonionic detergents Triton X-100 and Brij 36T induce dissociation and aggregation of the protein sesame α-globulin above the critical micelle concentrations (cmc) of the detergents. Spectrophotometric titration in Triton shows no change in the pK_Int value of the tyrosyl groups at 1 × 10^-3M detergent where both dissociation and aggregation of the protein are observed. Fluorescence measurement does not indicate any change in the environment of the tryptophan groups of the protein in Brij. Viscosity measurements show no major conformational change of the protein in the detergent solution. Binding measurements suggest that perhaps micelles of the detergent predominantly bind to the protein. The detergent micelles preferentially bind to the exposed hydrophobic surfaces of the protein subunits. The association of the protein detergent complex through electrostatic interaction is probably responsible for the formation of the aggregates.     

Acknowledgement of referees

Interaction of tamoxifen, trioxifene and LY117018 with cytosol-estrogen receptors from immature rat uteri was compared. Determination of relative binding affinity (RBA) by competition with [³H] estradiol under various assay conditions revealed that the RBA of LY117018 increased with temperature while that of tamoxifen and trioxifene declined. Furthermore, the RBA values of tamoxifen and trioxifene observed after 24 h of incubation at 4°C were significantly lower than those obtained with 1-h incubations. However RBA values obtained with 1- or 24-h incubations of LY117018 at 4°C were similar. The complex formed by estradiol or LY117018 at 4°C was relatively stable for 24 h, while significant dissociation of tamoxifen and trioxifene was detected under these conditions. At 30°C estradiol displayed a biphasic pattern of dissociation, but tamoxifen and trioxifene dissociated rapidly and little evidence of a stable phase was apparent. By contrast, the complex formed by LY117018 exhibited greater stability than that of estradiol at 30°C. These results establish a relationship between shifts in competition curves (RBA) and rates of dissociation relative to estradiol; and clearly reveal that LY117018 has different binding characteristics than tamoxifen and trioxifene.     

Adenosine 3',5'-monophosphate-dependent protein kinase from normal human adrenal.

The protein kinase of normal human adrenal cytosol has been resolved by DEAE-cellulose chromatography into two major components, the protein kinases I and II, which are both adenosine 3',5'-monophosphate (cAMP) dependent. Both enzymes have similar substrate specificities, cAMP-dependency, and sensitivity to the stimulation by this nucleotide, but differ in their states of activation after preincubation with histone. The DEAE--cellulose charomatography of dissociated cytosol protein kinase reveals only one peak of kinase activity and two peaks of cAMP binding activity (A and B). Both binding proteins are able to inhibit the kinase activity of the catalytic subunit. Recombination experiments suggest that the regulatory subunit A originated from protein kinase I and subunit B from protein kinase II. The phosphorylation of histone by adrenal protein kinases is inhibited by a heat-stable protein inhibitor isolated from human fetal brain and human adult adrenal.     

Changes in patterns of scaphoid and lunate motion during functional arcs of wrist motion induced by ligament division

PURPOSE: To determine the in vitro motion of the scaphoid and lunate during wrist circumduction and wrist dart-throw motions and to see how these motions change after the ligamentous stabilizers of the scaphoid and lunate are sectioned in a manner simulating scapholunate instability. METHODS: Twenty-one fresh-frozen cadaver forearms were moved through a dart-throw motion and a circumduction motion using a wrist joint simulator. Scaphoid and lunate motion were measured with the wrist ligaments intact and after sectioning of the scapholunate interosseous ligament, the scaphotrapezium ligament, and the radioscaphocapitate ligament. RESULTS: In the intact wrist the scaphoid and lunate moved more during circumduction than during the dart-throw motion. With ligamentous sectioning the scaphoid flexed more and the lunate extended more during both the circumduction and dart-throw motions. During the circumduction motion both before and after sectioning the global motion of the scaphoid was greater than that of the lunate. After sectioning the scaphoid motion increased and the lunate motion decreased. CONCLUSIONS: The scaphoid and lunate motions were observed to change remarkably after ligamentous sectioning. The observed changes in carpal motion correlate with the clinical observation that after ligamentous injury arthritic changes occur in the radioscaphoid joint and not in the radiolunate joint. Analysis of the injured wrist in positions that combine flexion-extension and radial-ulnar deviation may allow noninvasive diagnosis of specific wrist ligament injuries.     

Dissociation of the Factor-VIII complex during clotting: role of thrombin and phospholipids

Abstract. To study the dissociation of the two moieties of the factor-VIII complex during clotting, plasma, concentrate and serum were chromatographed on 4% agarose. In plasma and concentrate factor-VIII coagulant activity (VIII C), factor-VIII coagulant antigen (VIII C:Ag), and factor-VIII-related antigen (VIII R:Ag) eluted together in the void volume, but some VIII C: Ag eluted after the void volume. The amount of VIII C:Ag eluting after the void volume was made smaller by adding proteinase inhibitors. In serum nearly all VIII C:Ag eluted after the void volume.
From factor-VIII complex immunoadsorbed by means of an antibody against VIII R:Ag no VIII C:Ag was dissociated by thrombin or by thrombin and physiologic CaCl₂ concentrations. Radiolabelled human thrombin did not bind to the VIII C:Ag of immunoadsorbed factor-VIII complex. VIII C:Ag displaying VIII C was dissociated from immunoadsorbed factor-VIII complex by human brain thromboplastin or by phosphatidyl-serine.
Our results suggest that VIII C:Ag and VIII R:Ag dissociate during clotting. This dissociation seems not to be mediated by thrombin, but may be mediated by phospholipids.     

Pharmacokinetics of topically applied ophthalmic drugs

Pharmacokinetic applications in recent years have led to significant advances in systemic drug therapy, but applications to topical, ophthalmic therapy have been far less numerous. Pharmacokinetics is the study of the time course of the absorption, distribution, metabolism, and elimination of an administered drug. Thus, it includes the quantitation of such elements of drug bioavailability as tear dilution, drug binding, and vehicle effects; factors affecting corneal absorption and subsequent tissue distribution; dosage form effects; and pathways of elimination. These factors are important because they significantly influence the clinical responses to administered drugs, in some instances to a profound degree. These elements and their clinical implications are discussed along with some recent applications, exemplified with data from studies on frequently prescribed drugs.     

Predictors of acute distress among young adults injured by community violence

Acute reactions to trauma are examined in 267 individuals severely injured via community violence. Respondents were interviewed about pretrauma, peritraumatic, and acute posttraumatic factors. A series of bivariate and multivariate analyses were conducted. We found few factors related to peritraumatic dissociation (PD): only injury severity and neuroticism emerged as multivariate predictors and the effects were small. PD was strongly related to acute PTSD symptoms, and partially mediated the relationship between other factors and acute PTSD and general distress symptoms. Different patterns of predictors emerged for acute PTSD symptoms vis-à-vis general distress symptoms. Future research on predictors of PD is indicated to develop prevention and early intervention programs.     

Carpal bone postures and motions are abnormal in both wrists of patients with unilateral scapholunate interosseous ligament tears

PURPOSE: The recent ability to measure 3-dimensional in vivo carpal kinematics has facilitated the noninvasive study of complex carpal bone motion. METHODS: In this study we examined the flexion/extension carpal kinematics of both wrists in 8 patients with unilateral scapholunate interosseous ligament (SLIL) tears by using computed tomographic (CT) imaging and a markerless bone registration technique. Carpal bone neutral posture and flexion/extension motion of both wrists of the injured patients were compared with the same parameters in wrists of 10 uninjured male and female volunteers (normals). RESULTS: The neutral posture of the injured scaphoid and lunate were significantly more extended than those of normals. In these patients, however, the postures of the scaphoid and lunate in the contralateral uninjured wrists also were abnormal and were similar to those of the injured wrist. In addition, extension of the lunate and flexion of the scaphoid in both the injured and uninjured wrist were significantly different from normal but not different from each other. CONCLUSIONS: This study was unable to attribute altered carpal posture and motion to SLIL tears because abnormalities were found in both wrists of patients with unilateral injury. The etiology of abnormal wrist kinematics in the asymptomatic wrist of patients with unilateral tears of the scapholunate ligament is not known.     

Hypophosphatemia and acute respiratory failure in a diabetic patient

A previously healthy 48-year-old male developed diabetic ketoacidosis and severe hypophosphatemia. Within a few hours, acute respiratory insufficiency developed with a marked discrepancy between the pulmonary pathology and the very poor oxygenation seen. We argue that this was due to the effect of hypophosphatemia on respiratory muscle- and heart function and P₅₀, leading to impaired oxygen delivery.