Effects on the buoyant density of rabbit platelets of ADP and agents that increase the concentration of cyclic AMP

Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.     

Primary sphincter repair in anorectal trauma

Two patients who sustained severe anorectal trauma from "fist fornication" were treated by irrigation, colostomy, drainage, antibiotics, and primary repair of the rectum and anal sphincters without complications. Both had complete return of continence. Primary sphincter repair is advocated for these and similar anorectal injuries.     

Number of burr holes as independent predictor of postoperative recurrence in chronic subdural haematoma

Chronic subdural haematoma (cSDH) is one of the most frequent neurosurgical entities. Current treatment options include burr hole craniostomy, twist drill craniostomy or craniotomy. While burr hole craniostomy is the most often used technique, there are no studies analysing the use of one vs. two burr holes in respect to recurrence rates and complications. This retrospective study included 76 (age: 60 +/- 12 years) patients presenting with cSDH admitted in our institution from January 2004 to December 2005. A total of 21 (27%) patients underwent bilateral craniostomy. The patients were assessed using the Markwalder Scale (2 +/- 0.71), Glasgow Coma Scale (14 +/- 1) and measuring the haematoma thickness (1.8 +/- 0.7 cm). The decision to perform one or two burr hole was made according to the personal preference of the treating neurosurgeon. All patients underwent irrigation and placement of closed-system drainage. Out of the 97 haematoma, 63 (65%) haematomas were treated with two burr holes, whereas 34 (35%) were treated with one burr hole. Patients with one burr hole had a statistically significant (p < 0.05) higher recurrence rate (29 vs. 5%), longer average hospitalization length (11 vs. 9 days) and higher wound infection rate (9% vs. 0%). A multivariate regression analysis identified the number of holes as single predictor for postoperative recurrence rate (r(2) = 0.12; p < 0.001). In this study, the treatment of cSDH with one burr hole only is associated with a significantly higher postoperative recurrence rate, longer hospitalization length and higher wound infection rate.