Stroke Bricks - spatial brain regions to assess ischaemic stroke localisation.

Computer-aided analysis of non-contrast computed tomography (NCCT) images for rapid diagnosis of ischaemic stroke is based on the augmented visualisation of evolving ischaemic lesions. Computerised support of NCCT often leads to overinterpretation of ischaemic areas, thus it is of great interest to provide neurologically verified regions in order to improve accuracy of subsequent radiological assessment. We propose Stroke Bricks (StBr) as an arbitrary spatial division of brain tissue into the regions associated with specific clinical symptoms of ischaemic stroke. Neurological stroke deficit is formally translated into respective areas of possible ischaemic lesions. StBr were designed according to formalised mapping of neurological symptoms and were attributed to the uniquely defined areas of impaired blood supply. StBr concept may be useful for an integrated radiological CT-based assessment of suspected stroke cases or can be included into computer-aided tools to optimise the evaluation of stroke site and its extent. These data in turn are appropriable for further diagnosis, predicting the therapeutic outcome as well as for patients' qualification for an appropriate form of reperfusion therapy. The usefulness of StBr was illustrated in the case studies.

HIV infection of macrophages and pathogenesis of AIDS dementia complex: interaction of the host cell and viral genotype.

AIDS dementia complex (ADC) develops in only a third of HIV-infected patients who progress to AIDS. Macrophages and microglial cells are the major cellular sites of productive HIV replication in brain. Using 11 blood isolates of HIV from asymptomatic patients there was marked variation in tropism and the level of productive infection in recently adherent monocytes and monocyte-derived macrophages cultured in vitro. However, less variation was seen with 19 blood isolates from advanced HIV infection and 11 postmortem tissue isolates from brain, cerebrospinal fluid, spleen, and lung. Newly adherent monocytes expressed CCR5 in all seven patients tested, consistent with their susceptibility to infection but not explaining the above variability. There is, also marked regional variability in neuropathology in the brain of patients with ADC. We have demonstrated that there was marked variation in the V3 sequences of HIV clones from different regions of the cortex of a patient with ADC, suggesting independent evolution of HIV replication in brain. Furthermore, production of the neurotoxin quinolinic acid from HIV-infected macrophages varied, depending on the host and source of HIV isolate. Hence variations in viral genotype, production by infected macrophages, and subsequent toxin production may contribute to the variability in neuropathology between individuals and between different regions of the brain in the same individual.

The inhibition of HIV replication in monocytes by interleukin 10 is linked to inhibition of cell differentiation.

The effect of exogenous recombinant interleukin 10 on the replication of low-passage HIV-1 strains in blood-derived monocytes and monocyte-derived-macrophages (MDMs) was examined at various stages of cell maturation after adherence to the plastic substrate. Interleukin 10 inhibited extracellular production of HIV-1 to a greater degree in monocytes infected within 24 hr of adherence than those infected at 5-7 days. Inhibition of viral production as extracellular p24 antigen was most marked when interleukin 10 was preincubated with monocytes for 24-96 hr (optimum, 48 hr), and increased between 2 and 100 ng/ml. Neutralizing antibody to IL-10 reversed the inhibition. Inhibition of HIV production from monocytes and macrophages was maximal at 1 week after a single addition of cytokine, but then HIV production rose to control levels. Interleukin 10 was also found to inhibit reversibly the normal increase in size and maturation of both uninfected and HIV-infected monocytes during 10-15 days of adherence. In addition, cytoplasmic and membrane expression of CD26, a marker of macrophage maturation, was markedly inhibited but the proportion of detaching, apoptotic, or necrotic cells was also not increased. Hence, interleukin 10 reversibly inhibits both monocyte maturation and HIV production from infected monocytes with similar kinetics, suggesting that inhibition of monocyte maturation by IL-10 may have a marked effect of HIV production by these cells.

Unique HIV type 1 V3 region sequences derived from six different regions of brain: region-specific evolution within host-determined quasispecies.

HIV type 1 viral quasispecies were amplified by polymerase chain reaction (PCR) in the hypervariable V3 region of gp120 from six different regions of the brain (right and left frontal; right and left parietal; and right and left occipital) and from the peripheral blood mononuclear cells (PBMCs) of a patient who died of AIDS dementia complex (ADC). Cloning and sequencing of the entire V3 region suggested the presence of genetically unique sequences in different regions of the brain. In contrast, the blood-derived viral quasispecies carried homogeneous sequences that were characterized by a single octapeptide crest motif (HLGPGSAF), a motif important in viral fusion. The brain-derived viral strains showed extensive sequence heterogeneity and the presence of seven different octapeptide and four different tetrapeptide crest motifs (HIGPGRAF, RIGPGRAF, HIGPGSAI, HLGPGSAF, HIGPESAI, HLGPESAI, and YLRPGSAF). In addition, the brain-derived strains were also characterized by variable net V3 loop charge and hydrophilicity, along with distinct amino acid changes specific to different brain regions. Together, the sequence and phylogenetic analyses are unique in identifying the complexity of a viral quasispecies and its independent regional evolution within the brain compartment. Uniquely divergent viral strains were identified in the frontal regions and their presence was further supported by the presence of multinucleated giant cells (characteristic of HIV encephalopathy) predominantly in the left and right frontal regions. In summary, these analyses suggest that genetically different populations of HIV-1 may be present in different brain compartments and confirm that specific neurotropic variants may exist.

Molecular analyses of human immunodeficiency virus type 1 V3 region quasispecies derived from plasma and peripheral blood mononuclear cells of the first long-term-nonprogressing mother and child pair.

Molecular analyses were done for the V3 region quasispecies of human immunodeficiency virus type 1 (HIV-1) strains from plasma and peripheral blood mononuclear cells of the first HIV-1-infected long-term-nonprogressing mother-child pair whose members have survived for >13 years with stable CD4 T cell counts. There was a predominance of lower V3 loop charge and the absence of genotypic changes that are critical in phenotypic determination and tropism during HIV-1 infection. The intrahost genetic diversity between HIV-1 strains from the mother-child pair compared with HIV-1 strains from slow and rapid progressors suggested that a high genetic heterogeneity in HIV-1 strains from this HIV-1-infected long-term-nonprogressing mother and child pair was directly proportional to the length of their immunocompetent period.