The aim of the present study was to see if varying the rate and pattern of gastric distension affected its motor and sensory responses to distension. A balloon was used to carry out distensions in male volunteers at constant rates of 20, 50, 100, and 200 ml/min. In addition rapid (75 ml/s) intermittent distensions (RID) were carried out with the use of a large hand-held syringe. Subjects were asked to indicate the first perception of the balloon, fullness, and discomfort. Increasing the rate of ramp distension caused all sensations to occur at higher volumes and higher pressures and reduced the frequency and amplitude of phasic oscillations in gastric pressure. During RID, the same sensations were experienced at much reduced volumes but were poorly sustained. These data suggest that ramp and RID are likely to induce gastric sensations by activating different populations of receptors. The responses to ramp distension are compatible with the activation of stretch receptors situated in parallel with the muscle elements, whereas RID appear to be activating a different population of rapidly adapting mechanoreceptors possibly situated in the mucosa.

The structural changes in the hydrocephalic brain suggest that cell death must be a significant factor in the loss of cortical mantle thickness and cell numbers. In the developing hydrocephalic brain a similar conclusion might also be reached. We present data suggesting that in the developing hydrocephalic HTx rat brain, there are at least two processes that underlie the structural deficit in the cortex. The first is abnormal development of the cortex probably resulting from a combination of the genetic defect and blockage of CSF circulation in the fetus. The second is a direct consequence of raised intracranial pressure and is manifested in a lack of development of glial cells in the neonatal brain and in the loss of myelination and neurones as pressure rises after birth, particularly after skull plate fusion. We find little evidence of increased cell death by apoptosis, recording instead a decrease in apoptotic index. There is evidence that necrosis must have occurred.

The effect of hydrocephalus on the nitric oxide system in the brain of the HTx rat brain was investigated. We used NADPH-diaphorase histochemistry to stain neurones containing the enzyme, nitric oxide synthase. Comparison of normal and hydrocephalic HTx rat brains showed a reduction in stained neurones and a greatly depressed staining intensity in those that were labelled in the hydrocephalic brain. Also, there was an apparent reduction in number and length of radiating fibres from stained neurones. In addition to these changes we also observed a clear association between stained neurones and the microvasculature of the brain. This suggests that changes in the activity of these neurones may have a significant impact on the normal perfusion of the brain.

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Background: Idiopathic pseudotumour (IP) is a non-specific, non-neoplastic, inflammatory process without identifiable local or systemic causes. IP in the head and neck region present diagnostic and management issues.Methodology: Retrospective case series and literature review. Results:We describe clinical history, examination, laboratory investigations and image findings of three patients, all males who presented with facial pain and ophthalmoplegia. Scans revealed lesions in the pterygopalatine fossa. The diagnosis of idiopathic pseudotumour was confirmed by histopathology. We discuss their treatment pathways and prognosis.Conclusions: Idiopathic pseudotumours in the head and neck region especially those involving anterior skull base are rare.Understanding their presentation and characteristics might help an unsuspecting otorhinolaryngologist in the diagnosis and treatment of these lesions.