Pyrimidine 5'-nucleotidase deficiency: improved detection of carriers

The activities of pyrimidine 5'-nucleotidase (P5N) and the nucleotide pools in the erythrocytes from 19 members of a Dutch family with P5N deficiency were measured. In the erythrocytes of 5 (out of 6) apparent heterozygotes (based on P5N activities), an increased amount of UDP-N-acetylhexosamines was found. This increase was also found in the erythrocytes of 2 (out of 3) questionable heterozygotes (P5N activity below normal range, but not below normal mean--2 X SD) and not in the erythrocytes of family members with a normal P5N activity nor in erythrocytes from healthy donors. We conclude that analysis of the ribonucleotide patterns, in combination with determination of P5N activity, allows a more accurate diagnosis of heterozygosity for P5N.     

White Cell Count During Maintenance Chemotherapy for Standard-Risk Childhood Acute Lymphoblastic Leukemia: Relation to Relapse Rate

In a retrospective study of 84 children with standard-risk acute lymphoblastic leukemia diagnosed in 1981-1986, mean white cell count (mWBC) during maintenance chemotherapy (MT) was found to be significantly related to risk of hematological relapse, giving patients with the higher m WBC the poorer outcome. The only other significant relapse-related risk factor was white-cell count at diagnosis. mWBC was not significantly related to white cell count at diagnosis, sex, age, or dose of methotrexate or mercaptopurine. Patients with low mWBC also had relatively low white-cell counts after cessation of therapy when compared with patients with high m WBC.     

Pseudoaneurysms complicating organ transplantation: roles of CT, duplex sonography, and angiography

In a retrospective study of proved pseudoaneurysms (PAs) in 15 patients with transplanted organs (11 liver, three kidney, one pancreas), the results of computed tomography (CT), duplex sonography, and angiography were reviewed. Of the 15 cases of PA, eight occurred at the arterial anastomosis and seven were nonanastomotic. Three of the eight anastomotic PAs were caused by infection. Of the seven nonanastomotic PAs, four were caused by percutaneous biopsy, two were caused by infection, and one was of undetermined cause. In nine (60%) of the 15 patients the PAs were incidentally detected at imaging studies performed for other reasons. Diagnosis requires a high degree of suspicion. CT was performed in nine cases and duplex sonography in ten. The diagnosis of PA was made with CT in six (67%) patients and with duplex sonography in five (50%). CT and duplex sonography could not enable diagnosis when the PA was small, when the arterial anastomosis was not included in the field of study, or when enhancement with intravenously administered contract material was suboptimal. Angiography depicted the PAs in all 15 patients. In three liver transplant recipients with gastrointestinal tract bleeding, the causative PAs were detected only with angiography.     

Cyclosporine in steroid-resistant Diamond-Blackfan anaemia

Two siblings with Diamond-Blackfan anaemia (DBA) and several congenital malformations were first treated with corticosteroids and blood transfusions. High steroid doses were needed, but in spite of this haemoglobin values periodically fell below acceptable levels. Cyclosporine was then given in addition to prednisolone. A slow increase in haemoglobin levels was observed over 2-3 months, and the prednisolone doses could be reduced gradually. Two short communications in the literature report similar experiences. Cyclosporine could be tried in DBA when reasonable corticosteroid doses do not give a satisfactory response. Since the main effect of cyclosporine is a specific inhibition of T-lymphocytes, the observed therapeutic effect in DBA indicates that T-lymphocytes may play an important role in the pathogenesis of this disease.     

Spacing of cytochrome oxidase blobs in visual cortex of normal and strabismic monkeys

Some models of visual cortical development are based on the assumption that the tangential organization of V1 is not determined prior to visual experience. In these models, correlated binocular activity is a key element in the formation of visual cortical columns, and when the degree of interocular correlation is reduced the models predict an increase in column spacing. To examine this prediction we measured the spacing of columns, as defined by cytochrome oxidase (CO) blobs, in the visual cortex of monkeys whose binocular vision was either normal or disrupted by a strabismus. The spatial distribution of blobs was examined in seven normal and five strabismic macaques. Tangential sections through the upper layers of the visual cortex were stained to reveal the two-dimensional (2D) pattern of CO blobs. Each blob was localized and their center-to-center spacing, packing arrangement and density were calculated using 2D nearest-neighbor spatial analyses. The mean center-to-center spacing of blobs (590 microm for normally reared and 598 microm for strabismic macaques) and the mean density of blobs (3.67 blobs/mm2 for normally reared and 3.45 blobs/mm2 for strabismic macaques) were not significantly different. In addition, the 2D packing arrangement of the blobs was not affected by strabismus. While it is clear that neural activity plays a key role in the elaboration and refinement of ocular dominance cortical modules, we conclude that it does not determine the spatial period of the pattern of CO blobs. This suggests that aspects of the neural circuitry underlying the columnar architecture of the visual cortex are established prenatally and its fundamental periodicity is not modifiable by experience.      

A Case of Variant Congenital Dyserythropoietic Anemia Revisited

A patient with congenital dysterythropoietic anemia was described in 1975 as variant type II because of negative acidified lysis tests using 12 different fresh sera. Subsequent tests with 2 additional normal sera have been strongly positive.     

Erythrocyte Pyrimidine 5‘-Nucleotidase Deficiency

We present 2 Norwegian siblings who we believe to be the first cases of pyrimidine 5′-nucleotidase deficiency diagnosed in the Scandinavian countries. In addition to the features presented by previously published cases, our patients exhibited signs of intravascular haemolysis with haemoglobinuria and increased loss of iron in the urine. The loss of iron has made iron medication necessary from time to time. A kidney biopsy from the oldest patient revealed accumulation of iron in the epithelium of the proximal tubuli. The kidneys were considerably enlarged in both patients, but with normal function tests.