Radiographic assessment of instability of the knee due to rupture of the anterior cruciate ligament. A quadriceps-contraction technique

We compared the results of a radiographic technique for the measurement of instability of the knee with those obtained with a KT-1000 arthrometer. The study was conducted on both knees of sixty patients who had a ruptured anterior-cruciate ligament in one knee, as well as in ten control subjects. The radiographic technique included the examination of a true lateral radiograph, made while the knee was in full extension and the quadriceps was maximally contracted, with a 66.7-newton downward force produced by a 6.8-kilogram weight suspended from the ankle. As demonstrated by both techniques, the maximum difference between the displacements of the right and left knees in the control subjects was 2.5 millimeters and the mean difference between the displacements in the two knees in the patients was 7.5 millimeters. In fourteen of the sixty knees in which the ligament was ruptured, the injury was acute. The forward translation of the medial side in these fourteen knees was compared with that in the forty-six knees in which the injury was chronic. The mean difference in the displacement of the medial side in the right and left knees was 3.5 millimeters in the fourteen patients who had an acute injury and 5.0 millimeters in the forty-six patients who had a chronic injury. Thirteen of the sixty patients had disruption of the posteromedial corner of the injured knee, and the translation of the medial side in these knees was significantly increased compared with that in the intact knees of the same patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Succinylcholine pharmacodynamics in peripartum patients

Serum cholinesterase activity decreases 30% during pregnancy and remains depressed during the postpartum period. However, succinylcholine recovery is not prolonged in term-pregnant patients. This contrasts with results obtained in other patients with decreased serum cholinesterase activity. To better understand this paradox, the authors compared serum cholinesterase activity and recovery from succinylcholine, 1 mg/kg, in nonpregnant (with and without oral contraceptive use), in term-pregnant, and in postpartum patients. Serum cholinesterase activity was lower in both term-pregnant (3.66 +/- 0.39 U/ml, means +/- SE) and postpartum (2.84 +/- 0.35 U/ml) patients than in nonpregnant patients not taking oral contraceptives (5.01 +/- 0.33 U/ml, P less than 0.05). Cholinesterase activity in postpartum patients also was significantly lower than in nonpregnant patients taking oral contraceptives (4.81 +/- 0.63, P less than 0.05). In contrast, the time to 25% twitch-height recovery did not differ between term-pregnant (470 +/- 56 s) and nonpregnant patients taking (499 +/- 29 s) or not taking (501 +/- 21 s) oral contraceptives, but was significantly increased in postpartum patients (685 +/- 22 s, P less than 0.001). The similar duration of action of succinylcholine in term-pregnant patients (with decreased serum cholinesterase activities) and nonpregnant patients may be related to the increased volume of distribution of succinylcholine at term.     

Effect on fetal mouse development of exposure to MR imaging and gadopentetate dimeglumine

Pregnant mice were exposed to one of five regimens at 9.5 days of gestation: no treatment (group 1), intraperitoneal injection of normal saline (group 2), intraperitoneal injection of gadopentetate dimeglumine (group 3), intraperitoneal injection of gadopentetate dimeglumine and magnetic resonance (MR) exposure (group 4), and MR exposure alone (group 5). At 18 days of gestation, the mice were sacrifice and fetuses were removed and examined for the following end points: litter size, number alive or dead, fetal weight, extremity morphology, eye and ear development, and appearance of the head. A total of 739 fetuses were analyzed: group 1 (n = 161), group 2 (n = 149), group 3 (n = 142), group 4 (n = 136), and group 5 (n = 151). The only statistically significant difference was a lower mean fetal weight in the saline-injection group compared with the control group. The results show that MR exposure with and without gadopentetate dimeglumine had no adverse effect on the end points analyzed.     

Pituitary volume in pediatric obsessive-compulsive disorder.

BACKGROUND: Abnormalities in the limbic-hypothalamic-pituitary-adrenal (LHPA) axis have been implicated in the pathogenesis of obsessive-compulsive disorder (OCD). To our knowledge, however, no prior study has measured pituitary gland volume in OCD. METHODS: Volumetric magnetic resonance imaging studies were conducted in 31 psychotropic drug-na?ve children (10 boys, 21 girls) aged 8-17 years and 31 case-matched healthy comparison subjects. RESULTS: Pituitary volume was significantly smaller in patients with OCD as compared with healthy control subjects (11% smaller). Smaller pituitary volume in patients with OCD was associated with increased compulsive but not obsessive symptom severity. Boys with OCD had smaller pituitary gland volumes compared with control boys (20% smaller). No significant differences in pituitary volume were observed between girls with OCD and control girls. Boys with OCD had significantly smaller pituitary volumes than girls with OCD (31% smaller), whereas control boys also had smaller pituitary gland volumes compared with control girls (21% smaller). CONCLUSIONS: These findings provide new evidence of reduced pituitary volume in pediatric OCD that seems to be more prominent in male patients. The observed alterations in pituitary volume are consistent with neuroendocrine studies that have reported abnormalities in the LHPA axis in OCD.     

Modulation of GABA-stimulated Cl- flux by a benzodiazepine agonist and an 'inverse agonist' after chronic flurazepam treatment

Rats treated one week with flurazepam were killed while still on the drug or 48 h after termination of drug treatment. The brain 'microsac' preparation derived from the cerebral cortices was used for studying the GABA-stimulated chloride influx. There was no significant change in the basal or GABA-stimulated influx between control and treated groups. However, the effect of flunitrazepam to enhance 10 microM GABA-stimulated influx was significantly reduced, indicating tolerance. Methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3- carboxylate (DMCM), an 'inverse agonist' at benzodiazepine receptors, dose dependently inhibited 50 microM GABA-stimulated influx; chronic treatment did not alter the effect of DMCM. This study demonstrates that one week treatment with flurazepam produces tolerance to benzodiazepines without any change in the effect of GABA or DMCM. This indicates that GABA and benzodiazepine sites are differently modulated after chronic treatment with benzodiazepines. However, since both benzodiazepine and DMCM act on the same receptors it appears that the different 'domains' on the benzodiazepine receptor are differently altered during chronic treatment.     

Progressive hind limb paralysis in mice carrying a v-Mos transgene.

To study the function of the protooncogene Mos in mouse brain development we have created a transgenic mouse model system in which an activated form of the gene, the murine retroviral v-Mos gene, is highly overexpressed in the brain. Six transgenic founder animals and mice of one established transgenic line (line TG66) displayed a progressive hind limb paralysis with onset between 18 days and 9 months. The severity of the neurological phenotype correlated with pathological alterations and the degree of v-Mos expression in the brain which varied between individual animals of line TG66. The most striking feature of the brain pathology was the presence of large, abnormal astrocytes in the cerebellum, medulla, thalamus and in the dorsal horn of the spinal cord. These areas also contained shrunken and basophilic neurons whose cytoplasm was abnormally immunoreactive for phosphorylated epitopes of neurofilaments. In addition to neuropathologic changes, these mice also displayed aberrant eye lens differentiation and absence of hair cells in the inner ear. These results establish v-Mos transgenic mice as a model system to study progressive neurodegenerative disease and provide further evidence that the Mos protein-serine/threonine kinase has a function in brain development.     

Improvement in mammography interpretation skills in a community radiology practice after dedicated teaching courses: 2-year medical audit of 38,633 cases.

The authors conducted a complete audit of results of 38,633 mammographic examinations performed by 12 general radiologists during a 2-year period with a computerized reporting system. During this period, 11 group members attended 17 dedicated mammography courses. Audit results were analyzed for each radiologist and the entire group. In the 2nd year, the number of breast cancers diagnosed increased 50% (from 121 to 181), with a 6.5% increase in patient volume. Sensitivity increased from 80% to 87%, and there was no change in the positive predictive value of 32%. Median tumor size and node positivity decreased. Most major variables of population and technical factors were unchanged. Diagnostic approach was altered during the 2nd year, as shown by a 50% increase in the use of spot compression, magnification views, and sonography. Analysis of each radiologist's performance before and after attending mammography courses showed similar changes. These data suggest that dedicated mammography courses can help improve radiologists' performance and alter their interpretive approach.     

Hodgkin disease: CT of the thymus

The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.