Free-floating thrombus of the extracranial internal carotid artery

Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.     

A chemically defined medium for the culture of mature oligodendrocytes

A new chemically defined medium consisting of equal parts of Dulbecco modified Eagle's and Ham's F-12 media supplemented with insulin, sodium selenite, putrescine, and D+ galactose, which allows the long-term survival of mature oligodendrocyte pure cultures, is described. Immunohistochemical staining has shown that over 90% of the cells become positive for myelin proteins shortly following subculture. Contaminating astrocytes (2%) do not survive in this medium. Biochemical data have indicated that these purified oligodendrocytes express 2'3'-cyclic nucleotide 3'-phosphohydrolase and UDP-galactose ceramide galactosyltransferase activities. Electron microscopical examination revealed that the oligodendrocytes were mostly of medium-dark type and appeared to be identical to cells cultured in serum-containing medium. The ability to maintain pure oligodendrocyte cultures in such a defined medium will allow investigations concerning exogenous and endogenous factors involved in oligodendrocyte metabolism.     

Ultrastructural reversible changes in fish neuromuscular junctions after chronic exercise

Neuromuscular junctions (NJs) of fin muscles of teleostean fishes, Lebistes reticulatus, were ultrastructurally analyzed during 60 min of chronic exercise and a subsequent period of 90 min of induced recovery. NJs from 30-min-exercised fishes showed an almost complete depletion of synaptic vesicles (SVs), corresponding to 83% of SV consumption; 76% of axon terminals were branched at the end of this period. During the recovery period, it was possible to observe the reversibility of the changes induced by the exercise and the transitory events that lead to the reacquirement of the normal NJ morphology. After 15 min of rest, SV population increased to a value of 54.6 SVs/micron2 and the percentage of branched axons was 66.5%. At 60 min of recovery the number of SVs reached a value of 84.6 SVs/micron2. The SV population was fully reestablished at 80 min of rest, while the percentage of branched axons was found within normal ranges after 90 min of recovery. These results demonstrate that chronic exercise induced physiological depletion of NJ SVs and other axon terminal morphological changes, as well as that postexercise rest induces the reestablishment of the normal NJ morphology.     

Multimodality evoked potentials and early prognosis in comatose patients

In 112 comatose patients somatosensory, visual and auditory evoked potentials were registered within 36 hours after the onset of coma or admission. Main causes of coma were head injury, and intracerebral and subarachnoid haemorrhage. The initial bilateral loss of any evoked potential was associated with a mortality of 98%. Normal somatosensory evoked potentials were associated with a survival rate of 74%, while normal visual and normal auditory evoked potentials had a survival rate of 60% and 66%, respectively. It is concluded that SEPs can be valuable for the prognosis of coma after primary brain lesions.     

Reduction of reticulata neuronal activity by zolpidem and alpidem, two imidazopyridines with high affinity for type I benzodiazepine receptors

Zolpidem and alpidem, two imidazopyridines with high affinity for the type I benzodiazepine recognition site, have recently been proposed as preferential hypnotic (zolpidem) and anxiolytic (alpidem) drugs notable for the minor incidence of side-effects. To further characterize the molecular mechanism involved in the action of these drugs, we studied their effects in comparison with those of diazepam on the spontaneous electrical activity of substantia nigra pars reticulata (SNR) neurons. These cells have been shown to be extremely sensitive to various positive and negative modulators of GABAergic transmission. All three drugs consistently produced a dose-dependent (0.03-8.0 mg/kg i.v.) inhibition of the firing of SNR cells when administered as a single bolus. However, zolpidem was more potent and efficacious than diazepam or alpidem. The ID50s were 0.076, 0.492 and 0.821 mg/kg, respectively. When the drugs were injected in exponentially (ratio 2) increasing doses up to 8.0 mg/kg, the rank order for tachyphylaxis was zolpidem much greater than diazepam greater than alpidem. Since the effects of the drugs were abolished and prevented by a small dose (0.5 mg/kg i.v.) of flumazenil (Ro 15-1788), it is likely that the effects were mediated through activation of benzodiazepine receptors. The results indicate that the hypnotic, zolpidem, has a more potent inhibitory action on SNR cell activity than the anxiolytics, alpidem and diazepam.     

A modified algorithm for the management of ureteral calculi: 100 consecutive cases

We treated 100 consecutive ureteral calculi requiring intervention with a previously described algorithm. There were 16 ureteropelvic junction, and 18 upper, 22 mid and 44 lower ureteral calculi. Treatment was by a stent and extracorporeal shock wave lithotripsy in 10 ureteropelvic junction, 10 upper ureteral and 3 mid ureteral calculi, ureteroscopy and extracorporeal shock wave lithotripsy in 6 upper and 6 mid ureteral calculi, and ureteroscopy alone in 5 ureteropelvic junction, 2 upper and 12 mid ureteral calculi. All 44 lower ureteral calculi were treated successfully by ureteroscopy. Of the 100 patients studied 98 were treated by endourological methods (extracorporeal shock wave lithotripsy or ureteroscopy), while 2 required an operation (1 with a ureteropelvic junction calculus and 1 with a mid ureteral calculus). Over-all, 100 patients required a total of 125 procedures to accomplish successful stone removal. An algorithm is developed in which lower ureteral calculi are treated by ureteroscopy, mid ureteral calculi (large and dense) by stent bypass and extracorporeal shock wave lithotripsy or (lucent and fragile) by ureteroscopy, upper ureteral calculi by stent bypass and extracorporeal shock wave lithotripsy without manipulation, and impacted ureteral stones initially by ureteroscopy and, if necessary, then by extracorporeal shock wave lithotripsy.     

Primary tangential excision for hand burns

The article describes the correct technique of primary tangential excision in deep dermal and third-degree hand burns. The operation performed under tourniquet facilitates the preservation of viable tissue, which is of utmost importance in hand burns. The therapeutic results depend on the extent of destroyed tissue. Primary tangential excision prevents fibrosis due to prolonged infection and impaired circulation, thus creating much more favorable conditions for reconstruction and rehabilitation.     

Differences in the kinetic properties and sensitivity to inhibitors of human placental, erythrocyte, and major hepatic aldehyde dehydrogenase isoenzymes

(i) The characteristics of the major human hepatic isoenzymes of aldehyde dehydrogenase (ALDH), ALDH I and ALDH II, were compared with the ALDH activities found in human placenta and erythrocytes, (ii) In human liver biopsies, the Km of ALDH I was approximately 7 mumol/L whereas it was 32 mumol/L for ALDH II. The Vmax for ALDH I was 2-3 times greater than the ALDH II Vmax. Human liver ALDH I and II also differed in their sensitivity in inhibitors. Namely, ALDH I was less sensitive to disulfiram than the ALDH II isoenzyme. (iii) ALDH activity in human placenta and erythrocytes was much lower than in liver tissue. Kinetic data showed that placental ALDH isoenzyme had a high Km (in the millimolar range) and increased its activity raising the pH from 7.4 to 8.8, more than the hepatic ALDH I and ALDH II isoenzymes did. Erythrocyte ALDH activity presented a dual component; the smaller one was characterized by a low Km (micromolar range), whereas most of the ALDH activity showed a high Km (millimolar range). (iv) Placental ALDH was resistant to nitrefazole inhibition and was inhibited by disulfiram in a manner similar to the hepatic ALDH I isoenzyme; erythrocyte ALDH was more sensitive to the inhibitory action of disulfiram and nitrefazole. (v) It is concluded that erythrocyte and placental ALDH isoenzymes are different from the hepatic ALDH I and ALDH II forms. It is also suggested that placental and erythrocyte ALDH isoenzymes are different high-Km isoenzymes.     

Increased (L+)-lactic acid production in lysozyme-inactivated suspensions of human dental plaque

The effect of lysozyme-inactivation on L(+)-lactic acid (LA) production in dental plaque suspensions was evaluated. From 10 children 24-h plaque was collected and lysozyme activity inhibited by addition of goat antiserum to human lysozyme. Acid production was stimulated by addition of glucose. The results showed significantly increased LA levels (50-150%) in lysozyme-inactivated plaque suspensions from 8 of the subjects compared to untreated controls. The increase in acid production activity was not related to plaque lysozyme levels. The findings indicate that the presence of lysozyme may be limiting on acid production in the early dental plaque.