The diagnostic value of ultrasonography to determine the temporomandibular joint disk position

Objective. Temporomandibular joint (TMJ) arthrography and magnetic resonance imaging are the imaging techniques of choice in patients presenting with signs and symptoms of TMJ disorders suggesting soft tissue pathosis. With the disadvantage of arthrography as an invasive procedure and magnetic resonance imaging posing a problem in clinical availability and cost, the purpose of this study was to determine whether ultrasonography could be used to assess the presence or absence of disk displacement in patients with TMJ disorders.Study design. In 17 patients, 100 TMJ positions were investigated by static and dynamic ultrasonography to analyze the diskcondyle relationship. To compare the respective findings with those of a diagnostic method offering high accuracy, coronal and sagittal magnetic resonance imaging was carried out immediately afterwards.Results. With static ultrasonography showing a sensitivity of 0.41 and a specificity of 0.70 and dynamic ultrasonography a sensitivity of 0.31 and a specificity of 0.95, the data revealed that static and dynamic ultrasonography are marginal in detecting the presence of disk displacement, but dynamic ultrasonography is sensitive in detecting the absence of disk displacement. However, with a positive predictive value of 0.61 and a negative predictive value of 0.51 for static ultrasonography, and a positive predictive value of 0.88 and a negative predictive value of 0.55 for the dynamic technique, the results indicate that both modalities are insufficient in establishing a correct diagnosis for the presence or absence of disk displacement.Conclusion. In view of the fact that dynamic ultrasonography proved to be a reliable diagnostic aid for the detection of normal disk position, the results of this study should be of further interest and encourage research in its potential uses and diagnostic capabilities.     

Comparison of the antispermatogenic effects of a new D-homo-steroid and testosterone in rabbits

In comparison to testosterone, 18β-hydroxy-18α-methyl-16α, 17α-methylene-D-homo-5α-androstane-3-one (D-homo-S) shows more pronounced anti-gonadotrophic than androgenic properties in rats. The present study was initiated in rabbits to investigate the potential of D-homo-S to suppress spermatogenesis. D-homo-S in sesame oil was administered at the doses of 0.1 (DI), 3 (D II) or 10 mg (D III) per rabbit each day for 8 weeks. During treatment serum testosterone, sperm concentration and quality of sperm motility decreased, whereas sex drive, semen volume and seminal plasma concentrations of fructose and zinc were not changed in any of the groups. Testicular weight and intratesticular testosterone concentration decreased significantly in groups D II and DIII, while weights of accessory sex glands increased in those groups. Testosterone in the same dose regimen did not suppress sperm count, motility or serum testosterone, however, seminal plasma zinc concentration in group TIII and fructose in group TI increased. Testicular weight and intratesticular testosterone concentration decreased in group TIII only. On the other hand, the weight of the accessory sex glands increased in the same group.
In conclusion, D-homo-S suppresses spermatogenesis and increases accessory sex gland weights at doses, when testosterone is still ineffective. Thus, in rabbits D-homo-S appears to be a more potent androgen than testosterone but a dissociation between antigonadotrophic and androgenic properties could not be observed.     

High-frequency Components of Auditory Evoked Potentials Are Detected in Responsive but Not in Unconscious Patients

Background: The dose-dependent suppression of midlatency auditory evoked potentials by general anesthetics has been proposed to measure depth of anesthesia. In this study, perioperatively recorded midlatency auditory evoked potentials were analyzed in a time-frequency space to identify significant changes induced by general anesthesia.

Methods: Perioperatively recorded auditory evoked potentials of 19 patients, recorded at varying levels of anesthesia, were submitted to a multiscale analysis using the wavelet analysis. Energy contents of the signal were calculated in frequency bands 0-57.1 Hz, 57.1-114.3 Hz, 114.3-228.6 Hz, and 228.6-457.1 Hz. A Friedman test and a Dunn multiple comparisons test were performed to identify significant differences.

Results: Statistical evaluation showed a highly significant decrease of the wavelet energies for the frequency bands 57.1-114.3 Hz (P < 0.0001), 114.3-228.6 Hz (P < 0.0001), and 228.6-457.1 Hz (P < 0.0001) for the measuring points representing deep general anesthesia. This decrease is accompanied by a decrease in the wavelet energy of the frequency band 0-57.1 Hz of no statistical significance (P = 0.021) (level of significance set to P = 0.01). The changes are most prominent in the poststimulus interval between 10 and 30 ms.     

Volumetric Magnetic Resonance Imaging Evidence of Bilateral Hippocampal Atrophy in Mesial Temporal Lobe Epilepsy

Summary: Purpose : We measured absolute volumes and volume differences of hippocampi in patients with mesial temporal lobe epilepsy (MTLE) using volumetric magnetic resonance imaging (MRI) to determine the extent of bilateral atrophy in MTLE and to relate hippocampal volumes (HV) to outcome of temporal lobectomy.
Methods : HV and hippocampal differences (HD) were measured in 40 patients with MTLE determined by pathology of hippocampal sclerosis (HS) and compared with those of age-matched controls. Results were matched with surgical outcome.
Results : Hippocampi contralateral to lobectomy (right hippocampi 2.96 ± 0.49 cm³, left 3.14 ± 0.51 cm³) were significantly smaller than those of controls (right hippocampi 3.73 ± 0.52 cm³, left 3.60 ± 0.51 cm³ but were significantly larger than hippocampi ipsilateral to lobectomy (right hippocampi 2.63 ± 0.61 cm³, 2.18 cm³) as compared across groups by analysis of variance (ANOVA: F = 27.2, p < 0. 0001). The smaller hippocampus was ipsilatera1 to lobectomy in 39 of 40 cases. Seven of 40 MTLE patients (18%) had bilateral atrophy, defined by volumes of each hippocampi 2 SD lower than control means. Surgical outcome was independent of hippocampal asymmetry and bilateral atrophy measured by chi-square and Fisher's exact tests.
Conclusions : We determined that most patients with MTLE have some degree of bilateral, asymmetric hippocampal pathology. However, asymmetry and bilateral atrophy have no clear relation to surgical outcome.     

Perceptual and Cognitive Visual Functions of Parietal and Temporal Cortices in the Cat

We used reversible cooling deactivation to compare the functionsof cortices lining the middle suprasylvian (MS) sulcus and formingthe ventral portion of the posterior suprasylvian (vPS) gyrus.A battery of attentional, motion and mnemonic processing taskswere used and performance was examined during deactivation ofeach region. The results show a clear dissociation of functions.Deactivation of MS cortex resulted in profound deficits on avisual orienting task and on the discrimination of directionof motion, whereas deactivation of vPS cortex severely impairedboth retention and learning of novel and overlearned objectdiscriminations. In addition, deactivation of either MS or vPScortex impaired discrimination of learned patterns when componentsof the patterns were in motion, whereas only deactivation ofvPS cortex impaired the discrimination when all components werestatic. Together, these results show that a region of parietalcortex contributes to the processing of visual motion and toattentional processes, whereas a region of temporal cortex contributesto the learning and recognition of three-dimensional objectsand two-dimensional patterns. This functional dissociation islinked to differences in underlying visual pathways, which havemany features in common with the parietal and temporal visualprocessing streams previously identified in monkeys and humans.Furthermore, the broad similarity in neural operations carriedout in parietal and temporal cortices of cats, monkeys and humanssuggests the existence of a common plan for cortical processingmachinery within mammals with well developed cerebral cortices.     

Survival and aging of a small laboratory population of a marine mollusc, Aplysia californica

In a investigation of the postmetamorphic survival of a population of 112 Aplysia californica, five animals died before 100 days of age and five after 200 days. The number of survivors among the 102 animals which died between 100 and 220 days declined approximately linearly with age. The median age at death was 155 days. The animals studied were those that died of natural causes within a laboratory population that was established to provide Aplysia for sacrifice in an experimental program. Actuarial separation of the former group from the latter was justified by theoretical consideration.Age-specific mortality rates were calculated from the survival data. Statistical fluctuation arising from the small size of the population was reduced by grouping the data in bins of unequal age duration. The durations were specified such that each bin contained approximately the same number of data points. An algorithm for choosing the number of data bins was based on the requirement that the precision with which the age of a group is determined should equal the precision with which the number of deaths in the groups is known.The Gompertz and power laws of mortality were fitted to the age-specific mortality-rate data with equally good results. The positive values of slope associated with the mortality-rate functions as well as the linear shape of the curve of survival provide actuarial evidence that Aplysia age. Since Aplysia grow linearly without approaching a limiting size, the existence of senescence indicates especially clearly the falsity of Bidder's hypothesis that aging is a by-product of the cessation of growth.     

Effect of somatostatin analogue and cholecystokinin receptor antagonist on bile-induced acute canine pancreatitis.

To determine whether a synthetic somatostatin analogue, octreotide, and a cholecystokinin receptor antagonist, L-364,718, may be beneficial in acute pancreatitis, 33 dogs were assigned to four groups. Each dog underwent laparotomy with injection of autologous bile into the dorsal pancreatic duct. Thirty minutes after the induction of pancreatitis, Group 1 received a subcutaneous injection of octreotide (200 micrograms/kg), Group 2 received an equal volume of the octreotide carrier, Group 3 received an hourly intravenous bolus of L-364,718 (60 micrograms/kg), and Group 4 received an equal volume of the L-364,718 carrier. Hemodynamic profiles, arterial blood gases, plasma glucose, and serum amylase were obtained before laparotomy, at bile injection, and at hourly intervals. The pancreas was removed after 8 hours for gross evaluation, measurement of water content, and histologic examination. A significant decrease in cardiac index and a significant increase in serum amylase and pancreatic edema occurred in all four groups 8 hours after the induction of pancreatitis (P less than 0.05), but there was no statistical difference between any group. Likewise, there was no difference in gross or histologic changes in the pancreas of any group. The somatostatin analogue, octreotide, and the cholecystokinin receptor antagonist, L-364,718, did not ameliorate the effects of severe, bile-induced pancreatitis in dogs.