Ultrasonography of masseter muscle size in normal young adults.

The present study was planned to determine the relationship between linear dimensions of human masseter muscle cross-section and cross-sectional area (CSA), and to assess symmetry between the two sides in normal young adults. Cross-sectional images of the masseter muscle were measured bilaterally by real-time ultrasound imaging in 39 healthy dentate subjects, 19 males and 20 females, aged 21-47. From stored images, CSA and two linear measurements of muscle cross-section were obtained (the shortest and the longest distance through the muscle group). Correlation and regression analyses were performed to examine the relationship between CSA and the linear dimensions (both individually and with the linear dimensions multiplied). Symmetry of CSA between the two sides of the face was examined using the paired t-test. The significance of correlation coefficients (r) and the difference between the slopes of the regression lines were also examined. Masseter CSA was larger in males than in females. All correlation values between CSA and linear measurements were significant but muscle CSA was most accurately predicted when the linear measurements were multiplied (r = 0.97; P < 0.001). Although the correlation in this regard was high, the linear dimensions consistently overestimated the actual CSA by approximately 25%. Males showed more symmetry of CSA than females. The range of values for symmetry of masseter CSA was too large to assess abnormal asymmetry in patients with unilateral symptoms.

Intraosseous lipomas.

Intraosseous lipomas are considered to be rare tumours. We describe four cases and discuss their appearances and diagnosis. It is likely with the increasing frequency of computed tomography and magnetic resonance examinations of the lumbar spine that many more asymptomatic lesions will present to the radiologist and that these tumours are not as rare as the literature would suggest.

A case report: cervical pregnancy with placenta percreta an ultrasonic assisted diagnosis.

A rare cervical pregnancy is reported, discussing the difficulty differentiating this condition from the cervical phase of an incomplete abortion. Placenta percreta further complicates this case. Ultrasound will give a firm diagnosis of cervical pregnancy and associated placenta percreta. Conservative and radical surgical care determined by vital signs are discussed.

A clinical sign of low grade astrocytoma.

A useful sign in diagnosing an astrocytoma is described. It consists simply of observing whether the patient moves on to the CT table of his own accord. A case is presented where the CT findings were of a large, low attenuation lesion in the cerebral white matter and where the sign was positive. This indicated that the diagnosis was a low grade astrocytoma rather than infarction, cerebritis or oedema of another cause.

Adrenoleukodystrophy. A case report demonstrating unilateral abnormalities.

Adrenoleukodystrophy is a hereditary disorder characterized by progressive demyelination of cerebral white matter and adrenal insufficiency. Typical CT and MRI findings in the brain have been documented recently and consist of bilateral white matter abnormalities. We report the case of an 8-year-old boy whose CT and MRI scans showed unusually florid unilateral abnormalities.

Transient gyriform brightness on non-contrast enhanced computed tomography (CT) brain scan of seven infants.

Spontaneous gyriform brightness seen on CT scan is an unusual finding unless associated with arteriovenous malformations (AVM). There are sporadic case reports in the literature of its occurrence in association with herpex simplex virus encephalitis (HSVE), purulent meningitis, following chemotherapy for leukaemia, in a child with chronic renal failure, and in a child with folic acid deficiency. We present a series of seven cases exhibiting this phenomenon, none of whom have AVMs, who have been scanned at this hospital in the first 2 1/2 years following the installation of a CT scanner. Four of the cases had congenital heart disease requiring corrective surgery or cardiac catheterisation. The other three had probable meningo-encephalitis. In all cases the gyriform brightness followed an ischaemic insult to the child's brain. We hypothesise that this phenomenon is an ischaemic response in the immature brain and that its occurrence is not so rare as the literature may suggest.

Testis specific phosphoglycerate kinase B in mouse.

Mammals possess two genetically distinct forms of phosphoglycerate kinase (PGK). Only the X-linked PGK-A isozyme is detectable by electrophoresis of somatic and ovarian tissues of the mouse and of most other eutherian mammals studied to date. The PGK-B isozyme is highly active in testes and epididymides which contain spermatozoa, as well as in semen. PGK-B activity is first detectable in testes of 22-day-old mice and shows rapid increase concomitant with germ cell proliferation until day 40,after which activity increases only slightly. Two allelic isozymes (F and S) in mice express equal enzyme activity and are inherited in an autosomal codominant manner. One is equally as heat stable as PGK-A; the other is heat labile. Two of the 33 strains tested express neither F nor S, but do express a faintly staining PGK band which is of slightly faster mobility than F and which is absent from the other stains. This may represent a third allelic isozyme of PGK-B with reduced enzyme activity.