Responses of the isolated, perfused human spleen to sympathetic nerve stimulation, catecholamines and polypeptides.

1. The responses of the smooth muscle of the capsule and blood vessels of the isolated, perfused human spleen to sympathetic nerve stimulation, adrenaline, noradrenaline, angiotensin, oxytocin, vasopressin, isoprenaline and acetylcholine have been investigated and compared with those of dog spleen.2. Stimulation of the postganglionic sympathetic nerves to the human spleen at frequencies of 3-10 Hz evoked graded vasoconstriction but very small changes in spleen volume.3. The injection of adrenaline and noradrenaline in doses of 0.25-25 mug to the human spleen produced graded increases in splenic vascular resistance with very small decreases in spleen volume.4. Administration of the alpha-adrenoceptor blocking drug phenoxybenzamine completely abolished or considerably reduced the vascular responses of the human spleen to sympathetic nerve stimulation or the injection of noradrenaline.5. The vascular action of adrenaline was often reversed to elicit a vasodilatation after phenoxybenzamine suggesting the presence of beta-adrenoceptors in the vascular bed. This was confirmed by the administration of isoprenaline which induced a marked reduction in vascular resistance of the human spleen.6. The polypeptides angiotensin and vasopressin induced a marked vasoconstriction in the human spleen without changes in the spleen volume. These effects were uninfluenced by the administration of phenoxybenzamine.7. The polypeptide oxytocin caused a slight vasodilatation in the human spleen, an effect almost exactly mimicked by the preservative chlorobutanol.8. Preliminary experiments suggest that noradrenaline is the transmitter released by the postganglionic nerves to the human spleen.9. These results provide direct evidence that the normal human spleen, unlike that of the dog, does not have a reservoir function. It is suggested that contractions of the enlarged human spleen may occur in various pathological conditions.

Magnetic resonance renography: optimisation of pulse sequence parameters and Gd-DTPA dose, and comparison with radionuclide renography.

The aim of this study was to assess the feasibility of magnetic resonance renography (MRR) using gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) in comparison with conventional radionuclide renography (RR) using technetium-99m-DTPA (99mTc-DTPA). MRR has many advantages over RR, including lack of ionising radiation, increased spatial resolution, and visible background anatomy. By optimising the pulse sequence, we developed an MRR protocol in which signal intensity is linear with Gd-DTPA concentration over a clinically relevant range. Twenty-nine patients and a volunteer were studied using this protocol. Magnetic resonance renography was performed using three different doses of Gd-DTPA: 0.1 mmol kg-1 (n = 13), 0.05 mmol kg-1 (n = 7), and 0.025 mmol kg-1 (n = 9). Each patient was also assessed using radionuclide renography. The resulting renograms were assessed in terms of time to peak signal intensity, signal decrease after peak, and kidney function ratios calculated from both the areas underneath and the slopes of the uptake curves. We have shown that the MR renograms obtained using low dose Gd-DTPA correlate best with the radionuclide renograms. Remaining discrepancies may be explained by variations in the injection procedures (hence in arterial input functions) and the limited coverage of the three MRR slices compared to the whole body projection of RR. Furthermore, at high local concentrations, signal becomes independent of T1 and is dominated by T2.

Posterior pituitary ectopia and hypopituitarism--magnetic resonance appearances of four cases and a review of the literature.

In four patients presenting in childhood with varying degrees of hypopituitarism, magnetic resonance imaging (MRI) showed a reduction in size of the normal pituitary fossa contents and an absent or very narrow stalk. A high signal intensity, enhancing area at the base of the stalk, having the appearances and signal characteristics of the posterior pituitary, was seen in each case. We discuss the case histories and MR findings in our patients and review the relevant literature.

Evaluation of head examinations produced with a mobile CT unit.

Recent years have seen the development of mobile CT units, designed for use in operating theatres, intensive care units and accident and emergency departments. One such unit is the Tomoscan M (Philips, Utrecht, The Netherlands). It operates with a maximum tube voltage of 130 kV, and a maximum tube current of only 50 mA. This study tested whether acceptable quality CT images of the brain could be produced on the mobile unit with these parameters. 44 consecutive normal head examinations performed on the mobile scanner were compared with 35 examinations from two conventional CT units. Two independent readers scored the examinations for noise and artefact. CT dose index (CTDI) values for the three CT units were obtained in free air as an estimate of patient dose. Differences in artefact score between CT units were generally small, but noise scores were worse when using the Tomoscan M with a 2 s slice time. The lowest CTDI values were obtained with the Somatom DRH (Siemens, Erlangen, Germany) unit and the highest with the SR 7000 (Philips, Utrecht, The Netherlands), with values from Tomoscan M, in all except one case, falling between these values for the protocols used in the study. The measured scattered radiation doses from the Tomoscan M are presented.

Computed tomography in the evaluation of cutaneous T-cell lymphoma.

The computed tomography (CT) scans performed in 28 patients with cutaneous T-cell lymphoma (CTCL) were reviewed. Fifteen patients had clinically advanced cutaneous mycosis fungoides, six patients Sézary syndrome and seven variant CTCL. Of the 40 scans available 12 were normal, 15 indeterminate and 13 abnormal. Indeterminate and abnormal nodes showed a predilection for inguinal and axillary sites with a relative sparing of deep nodal regions. Visceral involvement was infrequent. In six patients CT detected abnormalities not obvious clinically and upstaged the disease. CT should be performed as part of the initial staging and as a baseline for follow-up in patients with advanced mycosis fungoides, Sézary syndrome and variant CTCL.

Symptomatic intracranial involvement by mycosis fungoides.

Involvement of the central and peripheral nervous system by mycosis fungoides is rare and usually occurs in the presence of widespread cutaneous and visceral disease. We describe a patient with mycosis fungoides, previously confined to the skin, who developed intracranial parenchymal disease with no evidence of systemic involvement.

Imaging the thoracic manifestations of AIDS.

Pulmonary complications occur in over half of patients with AIDS at some point in their illness. A chest X-ray is a valuable first-line investigation. The plain film and computed tomographic features of these complications are described and several examples illustrated. The role of computed tomography, including high resolution scanning techniques in further investigation and management, is discussed.

Pulmonary digital subtraction angiography: a screening tool for vascular lung lesions.

Pulmonary digital subtraction angiography offers a further method of distinguishing vascular from avascular lesions in the lung. The computerised (digitised) recording allows versatility of data manipulation and post-processing and is of particular value in identifying a vascular component in complex lung masses. In the five cases described, digital subtraction angiography provided useful information; in three, it was the definitive diagnostic procedure.

The role of transvaginal ultrasound in the assessment of the female pelvis.

Transabdominal ultrasound of the female pelvis has been compared with transvaginal ultrasound, using a 7.5 MHz transducer, in 80 women. Transvaginal ultrasound required less patient time and was preferred in 56% of patients. Image quality was superior in 72% of cases, and visualisation of the pelvic organs was equivalent with each technique. Transabdominal ultrasound gives a more global view of the pelvis, and is of more value in assessing large pelvic masses. Transvaginal ultrasound is of more value in assessing early pregnancy, ectopic pregnancy, ovarian abnormalities, and for visualising the ovaries following hysterectomy.

Phospholipase D1 is required for efficient mating projection formation in Saccharomyces cerevisiae.

Phospholipase D1 (PLD1) is an important enzyme involved in lipid signal transduction in eukaryotes. A role for PLD1 in signaling in Saccharomyces cerevisiae was examined. Pheromone response in yeast is controlled by a well-characterized protein kinase cascade. Loss of PLD1 activity was found to impair pheromone-induced changes in cellular morphology that result in formation of mating projections. The rate at which projections appeared following pheromone treatment was delayed, suggesting that PLD1 facilitates the execution of a rate-limiting step in morphogenesis. Mutants were found to be less sensitive to pheromone, again arguing that PLD1 is acting at a rate-limiting step. The fact that morphogenesis is most dramatically affected indicates that PLD1 functions primarily in the morphogenic branch of the pheromone response pathway.

Lymphocytic adenohypophysitis: magnetic resonance imaging features of two new cases and a review of the literature.

Lymphocytic adenohypophysitis can cause pituitary expansion and hypopituitarism closely mimicking the features of a pituitary adenoma. Discrimination between these two conditions is of importance since, despite the similarity of their presentation, there are significant differences in pathophysiology. In contrast to pituitary adenoma, lymphocytic adenohypophysitis occurs almost exclusively in young women in relation to pregnancy, there is a preference for destruction of ACTH and TSH secreting cells and computed tomographic scanning shows uniform contrast enhancement in a proportion of cases. There is, as yet, no proven specific non-surgical treatment. There are anecdotal reports of a beneficial effect of steroids but there is also evidence that spontaneous resolution may occur. We have reviewed the literature and report two new cases of lymphocytic adenohypophysitis both of whom exhibited early striking diffuse homogeneous contrast enhancement on magnetic resonance imaging scanning which we suggest may be a diagnostic feature of this condition.

Pictorial review: the imaging features of lower limb Klippel-Trenaunay syndrome.

The Klippel-Trenaunay syndrome is a rare mesodermal abnormality causing venous anomalies, cutaneous capillary naevi with bone and soft tissue hypertrophy of one or more limbs. In this pictorial review we illustrate the plain film, venographic, ultrasound and magnetic resonance imaging features of Klippel-Trenaunay syndrome affecting the lower limb.

Fracture of the sella turcica: a report of three cases.

Fractures of the sella turcica are rare. Recognition of fractures in this area is very important as serious immediate and delayed neurological, endocrine and vascular complications may occur. Most of these patients will develop at least one cranial nerve palsy; a significant number will develop hypopituitarism and a few will develop local vascular abnormalities.