The case of a 70-year-old woman with cerebral amyloid angiopathy (CAA) is presented. MRI of the head showed widespread miliary foci of haemorrhage within the cerebrum and cerebellum, with some additional linear lesions within the cerebral cortex and patchy lesions in the white matter. This is in contrast to the more usual pattern of intracranial haemorrhage in CAA, i. e., a lobar haematoma.

AIMS--Children in a United Kingdom national trial for relapsed non-B lymphoblastic leukaemia (ALL) had their diagnostic and relapse marrow cytomorphology compared to see what changes occur during the evolution of the disease. METHODS--Each relapse slide was assessed blindly for French American British (FAB) type and other morphological features by a panel of three independent microscopists without reference to each other or any diagnostic material. Diagnostic slides had been assessed by the same panel on an earlier occasion. RESULTS--A total of 134 consecutive children was studied. Six (5%) were classified as FAB type L2 at diagnosis, compared with 18 (13%) at relapse (a difference of 9%). Twenty two (16%) changed their FAB type, 17 (13%) from L1 to L2 and five (4%) from L2 to L1. The FAB score fell at relapse in 34 children and rose in 14, a difference of 14%. Cell size was the commonest feature to change (increasing in 22 and diminishing in nine) followed by prominent nucleoli (appearing in 21 and disappearing in six). Forty four (33%) children had vacuolated blasts at diagnosis, compared with 48 (36%) at relapse. Twenty five changed their vacuole score substantially, 14 gaining > 10% and 11 falling < 10%. CONCLUSIONS--These findings reflect the variability of lymphoblast cytomorphology, but also show a trend for cells to have more prominent nucleoli and greater size at relapse. Factors controlling these features of the FAB type are unknown, but they may simply be related to the growth fraction of a particular disease and not to any lineage specific biological feature.

Adults who have had repair of an open myelomeningocoele at birth are susceptible to a variant of adult onset tethered cord syndrome (ATCS). Precipitous and profound loss of lower extremity motor function occurred in two postrepair adult patients, but was not seen in any of our 12 cases of adult tethered cord with any other aetiologies. Both postrepair ATCS patients made a good recovery after surgical release of the tether. For the patients with other aetiologies, surgery yielded improvement or recovery of urinary continence in 57%, relief from pain in 78% and improved strength in 80%. Evidence of retethering was observed in 25% of the operated patients at intervals ranging from 1 to 9 years postoperatively. We conclude that surgical release of tether can reverse incontinence in ATCS of any aetiology and that in the post-myelomeningocoele repair patient, both dexamethasone and surgical intervention are helpful in reversing acute neurological deterioration.

AIMS:To assess the prevalence and degree of periodic acid Schiff (PAS) positivity in blast cells from children with lymphoblastic leukaemia (ALL); its association with other disease characteristics; and its clinical importance in predicting the outcome of treatment.METHODS:Marrow slides from entrants to a large United Kingdom multicentre ALL trial (UKALL X) were batch processed and assessed blind for PAS positivity by one morphologist. Patients were classified into groups A, B, and C, corresponding to less than 1% PAS positive cells, 1-10%, and over 10%, respectively. Their PAS pattern was then compared with other clinical and pathological features of ALL and with treatment outcome.RESULTS:Slides from 921 children were examined of which 371 (40%) were categorised as group A, 324 (35%) as group B, and 226 (25%) as group C. There was a clear association between the presence of blast cell vacuoles on Romanowsky staining and PAS positivity. Group A (PAS negative) patients included a disproportionate excess of those with L2 morphology, those under 2 or over 6 years of age, those with an initial white cell count over 50 x 10(9)/l, those with a T or null cell immunophenotype, and those with chromosomal abnormalities other than "high hyperdiploidy". Four years from diagnosis, group C patients had an 8% disease free survival advantage over those in group A (2p = 0.01). This was irrespective of initial white cell count, but not of immunophenotype or the presence of vacuoles.CONCLUSIONS:Strong PAS positivity is a feature of "common" ALL and is particularly associated with blast cell vacuoles. It does occasionally occur in other disease subtypes with or without vacuoles. It predicts a better response to current treatment, but not independently of other cell characteristics.

Blast cell morphology was assessed at diagnosis and subsequent bone marrow relapse in 33 unselected patients with lymphoblastic leukemia (ALL). Each marrow was classified 'blind' according to the French-American-British (FAB) criteria, and it was found that 19 of 24 (79%) patients initially typed as FAB L1 changed to FAB L2 during the course of their disease, but no patient made the reverse morphological change (p is less than 0.001). Five patients retained FAB L1 appearances; these included three of the four who had T-cell markers. One patient typed as FAB L3 did so consistently. This study indicates that FAB L2 ALL frequently emerges as a treatment-resistant offshoot of FAB L1 and provides further evidence that this marks a more aggressive form of the disease.

A semiquantitative assessment of blast cell acid phosphatase activity, expressed as a score, was made in 41 unselected children with newly diagnosed and untreated non-T acute lymphoblastic leukaemia (ALL). Despite a wide range of enzyme activity in both sexes boys had significantly higher scores than girls, and, in view of the known association between males and T ALL on the one hand, and between acid phosphatase and T ALL on the other, these findings raise the possibility that boys may have a predisposition to a type of pre-T ALL which could contribute to the as yet unexplained difference in prognosis between the sexes.

Most of the material sediments directly on to the grid, and large clumps of virus are usually easily seen in the first grid square. Almeida and Waterson4 stated that polio antigen-antibody aggregates require approximately 1 hour of spinning at 15 000 rpm. However, in our study, a large number of virus aggregates were seen after a spinning time of only 5 minutes at 2100 g in a clinical type bench centrifuge, but it is likely that spinning for a full half-hour would be necessary to sediment small clumps of virus into the grids. These aggregates consisted of both empty and core particles, free of cell debris, showing typical electron microscopic antigen-antibody reaction. A further feature of the technique described is that a quite low concentration of antibody may be used; around four times the neutralising titre is optimal. In addition the positive results obtained from diluted virus suspensions (Table 2) suggest that virus may be detected in cultures of low infective titre. It is important to avoid taking too much sample, otherwise an unacceptable quantity of debris, mostly from tissue cul ure cells, is deposited on the grid. It is likely that this method could be used satisfactorily for the typing of other viruses.

Bone marrow smears taken at diagnosis and subsequent haematological relapse from 41 patients with lymphoblastic leukaemia (ALL) were compared to assess the proportion of blast cells showing a positive periodic acid-Schiff (PAS) reaction at different stages of the same disease. 20 patients never displayed more than 10% PAS positive blasts at any stage, and of these 8 never had any PAS positivity at all. 7 patients maintained a proportion of PAS positive cells over 10% of the total but with no loss or gain in the numbers of such cells. 14 patients showed a significant change in the PAS reaction during the course of their disease, 7 showing a marked reduction in PAS positive cells, and 7 showing an equally marked increase. From these results it seems that the PAS reaction does not identify a sub-type of ALL or mark the degree of differentiation of a given case. It could be indicative of a specific stage of the lymphoblast mitotic cycle.

Diagnostic bone marrow smears from 132 patients with acute lymphoblastic leukaemia, (ALL) were stained simultaneously by the periodic acid-Schiff (PAS) reaction, and the blast cell positivity was assessed quantitatively. The patients fell naturally into two unequal groups: those with more than 20% PAS-positive blast cells (44 patients) and those with less (88 patients). There was no relation between the degree of positivity and age, sex, or presenting leucocyte count. Actuarial survival studies showed that the group with more than 20% PAS-positive blast cells survived longer, but that this difference assumed statistical significance only after the exclusion of patients over 14 years old and those with high white cell counts at the time of diagnosis. It appears that the PAS reaction can identify long survivors among patients with ALL, but not in the absence of features strongly associated with a poor prognosis.