Aplastic crisis as a complication of congenital dyserythropoietic anemia type II.

A transient aplastic crisis (TAC) is a well-known complication in all types of chronic hemolytic anemia but only 2 cases of such an event were described in congenital dyserythropoietic anemias (CDAs). Here, we report a third case, and by retrospective chart review of 78 cases we found evidence of TAC in 8 further patients with CDA II, with serological evidence of previous human parvovirus B19 (B19V) infection in all but one. Although B19V infection results in TAC in only a minority of patients with CDA, physicians responsible for these patients should be aware of such a potentially life-threatening complication. Testing for B19V-specific IgG is recommended in patients with CDA to estimate the risk of a possible future aplastic crisis.

Fatal outcome in a patient developing Epstein-Barr virus-associated lymphoproliferative disorder (EBV-LPD) without measurable disease.

A 51-year-old female patient in the first chronic phase of CML received an allogeneic PBSCT from a matched unrelated donor. The transplant was manipulated by CD34+ cell selection. On day +193 after transplantation the patient was readmitted to the hospital with recurrent fever of unknown origin and cough. Clinical, radiographic and sonographic evaluation revealed no characteristic findings besides a mild splenomegaly. Screening for EBV, CMV, RSV and HSV did not indicate an active infection. On day +203 the patient developed generalized seizures, respiratory failure and died within 24 h in multiorgan failure. The macroscopic postmortem was still not enlightening; the histological examination however, demonstrated diffuse organ infiltration by monoclonal lymphoblastoid cells due to EBV-LPD.

Indolocarbazoles exhibit strong antiviral activity against human cytomegalovirus and are potent inhibitors of the pUL97 protein kinase.

We have analyzed a panel of protein kinase inhibitors (PKIs) and found that some indolocarbazoles (Gö6976, K252a, K252c) proved to be highly effective inhibitors of GCV-sensitive and -resistant human cytomegalovirus (HCMV) strains, but did not show any effect against herpes simplex virus. Antiviral activity was determined by focus reduction assays (IC(50) ranging from 0.009 to 0.4 microM). Other inhibitors of serine/threonine kinases (Gö6850, H-7, roscovitine) were found to be ineffective. Virus yield at 5 days after infection was reduced by three orders of magnitude with nanomolar concentrations of the indolocarbazoles. These compounds were fully effective when added up to 24 h post infection and showed reduced activity up to 72 h post infection. Cytotoxicity assays in proliferating and non-proliferating cells demonstrated that the effective antiviral concentration of these compounds was significantly lower than either antiproliferative (IC(50)/CC(50) ranging from 6.5 to 390) or cytotoxic (IC(50)/CC(50) ranging from 72. 5 to 1000) doses. The effects of PKIs on the virus-encoded protein kinase pUL97 were studied using recombinant vaccinia viruses. Indolocarbazoles strongly inhibited both pUL97 autophosphorylation (IC(50) ranging from 0.0012 to 0.013 microM) and pUL97-dependent ganciclovir phosphorylation (IC(50) ranging from 0.05 to 0.26 microM). Other inhibitors of serine/threonine kinases showed only weak (Gö6850) or no (H-7, roscovitine) effect on these pUL97 functions, while oxoflavone tyrosine kinase inhibitors had no effect at all.

The hepatitis B virus X protein transactivates viral core gene expression in vivo.

The function of the X protein in the life cycle of mammalian hepadnaviruses is unclear. Based on tissue culture experiments it has been suggested that this protein represents a transcriptional transactivator which might be essential for the expression of the viral core gene. Here we have examined whether the activity of the human hepatitis B virus (HBV) core gene in vivo depends on X coexpression. To this end we compared core gene expression between four lineages of transgenic mice carrying the HBV core gene in cis arrangement with the X gene (cex lineage) and six lineages containing a modified construct in which the start codon of the X gene had been deleted (ce lineage). Whereas all cex lineages consistently exhibited a high-level hepatic core gene expression, the liver-specific core gene expression pattern of the ce lineages was heterogenous with four lineages virtually not expressing the core gene. This defect was due to a strongly reduced transcription since no core mRNA could be detected by Northern blotting. To test whether core gene expression could be restored by providing an intact X gene in trans, we crossbred mice of two lines which expressed no core mRNA or core protein with transgenic mice expressing the X-gene product under the transcriptional regulation of the liver-specific major-urinary-protein promoter/enhancer (MUP-X mice). The introduction of the MUP-X transgene induced core mRNA expression and core protein biosynthesis in the livers of the double-transgenic mice. This demonstrates that the X-gene product has the capacity to transactivate HBV core gene expression in vivo.

Local similarity in organic crystals and the non-uniqueness of X-ray powder patterns.

Two new concepts for molecular solids, 'local similarity' and 'boundary-preserving isometry', are defined mathematically and a theorem which relates these concepts is formulated. 'Locally similar' solids possess an identical short-range structure and a 'boundary-preserving isometry' is a new mathematical operation on a finite region of a solid that transforms mathematically a given solid to a locally similar one. It is shown further that the existence of such a 'boundary-preserving isometry' in a given solid has infinitely many 'locally similar' solids as a consequence. Chemical implications, referring to the similarity of X-ray powder patterns and patent registration, are discussed as well. These theoretical concepts, which are first introduced in a schematic manner, are proved to exist in nature by the elucidation of the crystal structure of some diketopyrrolopyrrole (DPP) derivatives with surprisingly similar powder patterns. Although the available powder patterns were not indexable, the underlying crystals could be elucidated by using the new technique of ab initio prediction of possible polymorphs and a subsequent Rietveld refinement. Further ab initio packing calculations on other molecules reveal that 'local crystal similarity' is not restricted to DPP derivatives and should also be exhibited by other molecules such as quinacridones. The 'boundary-preserving isometry' is presented as a predictive tool for crystal engineering purposes and attempts to detect it in crystals of the Cambridge Structural Database (CSD) are reported.