Pituitary fossa: chemical shift effect in MR imaging

The effect of chemical shift on magnetic resonance (MR) imaging of the pituitary fossa was studied. Healthy volunteers underwent conventional MR imaging of the pituitary fossa and then imaging with the frequency-encoding gradient reversed or with the phase- and frequency-encoding gradients interchanged. Comparison of the image pairs in each subject showed that the thin, black stripe evident at the water-fat interface within the pituitary fossa was altered when the gradients were changed. Therefore, the low-intensity signal within the pituitary fossa is a chemical shift misregistration effect.     

Anulus fibrosus in bulging intervertebral disks

In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks.     

B-cell function in patients with chronic lymphocytic leukemia

Summary Using a reverse hemolytic protein A plaque assay, spontaneous and pokeweed mitogen (PWM)-induced immunoglobulin (Ig) secretion was determined in peripheral blood from 22 patients with B₁-chronic lymphocytic leukemia (CLL), one patient with B₂-CLL, and one patient with suppressor T-CLL. Diagnoses were established by cytological and histological criteria as well as several marker analyses. Lymphocytes from B₁- and B₂-CLL patients were unable to secrete Ig either spontaneously or after PWM stimulation. In T-CLL lymphocytes, spontaneous Ig secretion was suppressed very probably by the OKT-8-positive leukemic population, since, after cultivation with PWM, a normal Ig secretion could be demonstrated which was paralleled by a decrease in the OKT-8-positive cells. Cocultivation experiments with freshly isolated, unseparated lymphocytes from normal subjects and lymphocytes from patients were of no informational value, since isolated normal B-cells alone already showed a high rate of Ig secretion. However, coculture experiments with separated subpopulations after PWM stimulation revealed an intrinsic B-cell defect in lymphocytes from B₁-CLL patients, whereas their T-lymphocytes were found to be normal helper cells.

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Abbreviations CLL Chronic lymphocytic leukemia - PWM Pokeweed mitogen - ISC Immunoglobulin-secreting cells - Ig Immunoglobulin(s) Supported by the Deutsche Forschungsgemeinschaft (Ru 215/2)     

Osteopetrosis: MR characteristics at 1.5 T

Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements.     

Behavioral effects of hashish in mice

The acute and subchronic effects of hashish extract (20 mg ⁹-THC/kg) on the social interactions between two drug-treated residents and an untreated intruder male were investigated. In this analysis 28 different behavioral elements were recorded.A single drug application suppressed all categories of behavior, except submissive behavior and flight, in dominant and subordinate residents. Treated animals were less active than controls and immobility was very frequent. An elevated total activity, due to an increase in non-social activities, was observed in the untreated intruder males of this group. Social investigation as well as submissive behavior and flight were reduced in these animals.On introduction of an untreated male after the fourth drug treatment of the residents, the drugged males showed tolerance to the sedative and most of the other behavioral effects of the drug, and intruder males behaved quite normally.The formation of a dominant-subordinate relation within the group was influenced neither by a single nor by repeated drug treatment.The acute and subchronic effects of hashish extract on social, especially aggressive behavior of males are compared to those described in previous papers and the variation in the results of the different studies is discussed.