B-cell chronic lymphocytic leukemia with aberrant CD8 expression: genetic and immunophenotypic analysis of prognostic factors

B-cell chronic lymphocytic leukemia (B-CLL) is phenotypically characterized by cell surface co-expression of CD19, CD20, CD5, and CD23. However, the concomitant presence of other antigens distinctive of a particular leukocyte subset, e.g. T cells, is an unusual finding in B-CLL. In the present report, a case of B-CLL with aberrant expression of the T-cell-associated antigen CD8 is described. Flow cytometric analysis of the patient's cells demonstrated lack of CD38 expression, and cytogenetic analysis by FISH did not show any abnormalities of chromosomes 17p, 11q, and 12. Furthermore, the B-CLL cells expressed only low levels of the tyrosine kinase ZAP-70, which was in agreement with the mutated status of the immunoglobulin heavy-chain variable-region gene (IgVH). In summary, the determined profile of prognostic markers together with the highly stable and indolent disease in the described patient suggest a good prognosis of B-CLL with aberrant CD8 expression.     

Visualizing the course of antigen-specific CD8 and CD4 T cell responses to a growing tumor

Spontaneous tumors frequently express antigens that can be recognized by the immune system but nevertheless manage to evade immune surveillance. To better understand the mechanism of evasion, we followed CD8 and CD4 T cells reacting against a subcutaneously growing tumor, modified to express influenza hemagglutinin (HA) as surrogate tumor antigen. Adoptive transfer of 8,000 antigen-specific CD8 T cells was sufficient to protect against challenge with 1x10(6) tumor cells, while larger numbers of T cells rejected established tumors. HA-specific CD4 T cells could not reject tumors on their own but helped rejection by CD8 T cells. Rejection of the tumor coincided with prolonged survival of expanded antigen-specific CD8 and CD4 T cells, while a failing anti-tumor response was accompanied by transient expansion followed by rapid elimination of antigen-specific T cells. Thus, a highly immunogenic tumor can evade immune surveillance because of an insufficient number of tumor-specific T cells and antigen overload, resulting in exhaustion of the immune response. In this scenario, adoptive immunotherapy rather than vaccination promises successful treatment.     

Molecular characterization of ampicillin-resistant Enterococcus faecium isolates from hospitalized patients in Norway

The genetic relationship of 81 ampicillin-resistant and 21 ampicillin-susceptible Enterococcus faecium isolates from clinical infections and rectal screening in hospitalized patients in Norway was studied by pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP). PFGE showed 55 different banding patterns, and 65 of the isolates could be grouped into one large group. With AFLP, 46 patterns were discerned, and 74 isolates clustered in one group. In general, the isolates had a higher degree of similarity than with PFGE. The purK gene, which is one of the targets of the E. faecium multilocus sequence typing scheme, was sequenced. Eleven different purK alleles could be discerned, with the majority of isolates (n = 80) harboring allele 1. With only two exceptions, all strains carrying purK-1 clustered in the same PFGE and AFLP groups, indicating a good correlation between PFGE type, AFLP type, and purK allele. Genetic polymorphism of a 571-bp PCR fragment of the C-terminal domain of the penicillin-binding protein 5 gene (pbp5) was determined, and sequence differences were associated with the level of ampicillin resistance. This study indicates that the majority of ampicillin-resistant E. faecium strains in Norway belong to a distinct genetic lineage of closely related genotypes. Rectal and clinical isolates were generally indistinguishable, and differences in clonal distribution and allele polymorphism were found mainly between ampicillin-resistant and -susceptible isolates.     

Intracochlear insertion of electrodes using hyaluronic acid in cochlear implant surgery

Hyaluronic acid has been proposed as a lubricant for improving the outcome of cochlear implant surgery. We describe a method which includes coating the electrodes with a thin layer of hyaluronic acid as well as using a droplet of the lubricant on the cochleostomy to provide additional magnification, like a lens, that facilitates the insertion of the electrode array. The use of hyaluronic acid reduces trauma to the cochlea and avoids contaminating perilymph by blood or by saline used during the operation. It is an efficacious and reliable method for cochlear implant surgery.     

Clarion 1.2 standard electrode array with partial space-filling positioner: radiological and histological evaluation in human temporal bones

The purpose of this study was to evaluate whether use of a positioner for situating the Clarion 1.29 standard electrode array in close proximity to the modiolus, causes damage to fine intra-cochlear structures, and to provide a comparison with results obtained for insertions of the array performed without a positioner. The study was performed in seven freshly frozen human temporal bones. Electrode location and intra-cochlear trauma was analysed using cross-sectional imaging and histological analysis. Insertion of the Clarion array did not reveal major trauma. The devices inserted with the positioner showed a consistently closer location of the electron array towards the modiolus, however, insertion resulted in significant displacement of both the electrode array and the positioner resulting in severe destruction of the basilar membrane and osseous spiral lamina along the length of the basal and middle turns. The devices inserted with the positioner resulted in major trauma to the basilar membrane and osseous spiral lamina. Therefore, systematic safety studies in larger samples of human temporal bones should be performed and the results carefully evaluated before implantation can be recommended unreservedly.     

Cerebral oxygenation is affected by filling mode and perfluorochemical volume in partial liquid ventilation of healthy piglets

Intrapulmonary administration of perfluorochemicals (PFC) has been suggested for reasons other than respiratory insufficiency. PFC application has been described to affect cerebral Hb concentration, however, data for healthy lungs are missing. Newborn piglets were randomized into 3 groups (30-ml slow-filling, 10-ml slow-filling and 30-ml rapid-filling), orally intubated and mechanically ventilated. Partial liquid ventilation (PLV) was initiated by filling the lung with PF5080 (10 or 30 ml/kg) at a rate of 1.5 ml/min (slow filling) or within 45 s (rapid filling). Vital signs, blood gases, tidal volume (VT) and changes in the cerebral concentration of oxygenated hemoglobin (HbO(2)) and total Hb were determined for up to 20 min. Rapid administration of PFC caused an immediate drop in HbO(2), PaO(2) and VT. The concentration of oxygenated and total Hb increased thereafter and remained high. We found a slow increase in PaCO(2), HbO(2) and total Hb in the 30-ml slow-filling group, but almost no changes in the 10-ml slow filling group (except for a decrease in PaO(2)). According to our data, PLV with 10 ml/kg should be preferred since cerebral alterations are minimal. If complete filling of the lung is needed PFC should be administered slowly to minimize side effects.