Post-rejection ureteral obstruction owing to ureteral adherence to graft inferior pole

We describe 2 renal transplant patients with increasing plasma creatinine levels after resolution of acute rejection episodes. Antegrade pyelography demonstrated adherence of the ureter to the inferior pole of the kidney with partial obstruction in both cases, which was confirmed at operation.     

Reversible shifts in the Ca2+-dependent release of aspartate and glutamate from hippocampal slices with changing glucose concentrations

It is known that low glucose concentrations increase the aspartate and decrease the glutamate content of brain tissue both in vivo and in vitro. To see whether these changes occur in the transmitter compartment or not, the release of aspartate and glutamate evoked by electrical-field stimulation or by high K+ was followed in slices of rat hippocampus superfused with 5 or 0.2 mM glucose. Superfusion with 0.2 mM glucose increased the evoked release of aspartate about ten times and that of glutamate about threefold. This shift in the ratio of aspartate to glutamate released was accompanied by a similar increase in the relative amount of aspartate contained in the slices. The high evoked release of aspartate and glutamate was well maintained, provided 0.5 mM glutamine was added to the medium. Changing the concentration of glucose after the first period of stimulation rapidly altered the relative amounts of aspartate and glutamate released but not the enhanced release of glutamate. The large evoked release of both aspartate and glutamate in 0.2 mM glucose was almost entirely Ca2+-dependent. The relative amounts of aspartate and glutamate released by 50 mM K+ also changed when the glucose concentration was reduced. Results suggest two effects of low glucose concentrations: an increase in the overflow of synaptically released glutamate due to a decreased uptake and an increase in the proportion of aspartate to glutamate formed and released from the transmitter pool. These observations are consistent with the interpretation that these two transmitters can be released in different proportions from the same terminals.     

Shoulder instability: impact of glenohumeral arthrotomography on treatment

We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.     

Actions of ethanol and acetate on rat cortical neurons: ethanol/adenosine interactions.

Recent studies have suggested that ethanol may exert some of its central depressant actions by increasing the extracellular levels of adenosine in the brain. Ethanol can inhibit the cellular uptake of adenosine, thus increasing its extracellular concentration. After ethanol metabolism by the liver, blood acetate levels are elevated and acetate metabolism in the brain could also lead to the production of adenosine. Rat cerebral cortical cup release experiments failed to reveal any elevation in the extracellular levels of either adenosine or inosine following the intraperitoneal (IP) administration of ethanol (1.5 g/kg) or acetate (2 g/kg). IP-administered ethanol (0.5 and 1.0 g/kg) enhanced the magnitude and duration of the inhibition by iontophoretically applied adenosine of the spontaneous firing of rat cerebrocortical neurons; an action which would be consistent with the block of adenosine uptake. Acetate, applied iontophoretically, depressed the spontaneous firing of 63% of the cerebrocortical neurons tested. 8-p-Sulphophenyltheophylline, an adenosine antagonist, was ineffective at blocking these inhibitions, indicating that adenosine generation is unlikely to have played a major role in the acetate-evoked depression of cerebral cortical neurons.     

Rupture of the posterior tibial tendon: CT and surgical findings

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.