HIV-1 predisposed to acquiring resistance to maraviroc (MVC) and other CCR5 antagonists in vitro has an inherent, low-level ability to utilize MVC-bound CCR5 for entry

In 2009, a newly discovered human retrovirus, xenotropic murine leukemia virus (MuLV)-related virus (XMRV), was reported by Lombardi et al. in 67% of persons from the US with chronic fatigue syndrome (CFS) by PCR detection of gag sequences. Although six subsequent studies have been negative for XMRV, CFS was defined more broadly using only the CDC or Oxford criteria and samples from the US were limited in geographic diversity, both potentially reducing the chances of identifying XMRV positive CFS cases. A seventh study recently found polytropic MuLV sequences, but not XMRV, in a high proportion of persons with CFS. Here we tested blood specimens from 45 CFS cases and 42 persons without CFS from over 20 states in the United States for both XMRV and MuLV. The CFS patients all had a minimum of 6 months of post-exertional malaise and a high degree of disability, the same key symptoms described in the Lombardi et al. study. Using highly sensitive and generic DNA and RNA PCR tests, and a new Western blot assay employing purified whole XMRV as antigen, we found no evidence of XMRV or MuLV in all 45 CFS cases and in the 42 persons without CFS. Our findings, together with previous negative reports, do not suggest an association of XMRV or MuLV in the majority of CFS cases.     

Effects of hypolimnetic oxygenation on water quality: results from five Danish lakes

Stratified eutrophic lakes often suffer from hypolimnetic oxygen depletion during summer. This may lead to low redox conditions and accumulation of phosphate and ammonia in the hypolimnion. Hypolimnetic oxygenation has been used as a lake management strategy to improve the water quality in five eutrophic dimictic Danish lakes where oxygenation was conducted for 4–20 years. In one lake, the hypolimnetic oxygen concentration clearly improved by oxygenation, whereas the other four lakes still exhibited low mean summer levels (<2.2 mg O₂ l⁻¹). Oxygenation generally increased the hypolimnetic water temperature by 0.5–2°C, but in one lake it increased by 4–6°C. In all lakes, oxygenation significantly reduced the hypolimnetic concentrations of phosphorus and ammonia during stratification. The accumulation of phosphorus and ammonia typically decreased by 40–88%. In two lakes oxygenation was stopped for 1–2 years and here hypolimnion concentrations of both phosphorus and ammonia increased again. Surface water quality only improved in one lake, but was likely also influenced by simultaneously occurring changes in external nutrient loading. Overall, it is concluded that hypolimnetic oxygenation reduces the hypolimnetic accumulation of phosphorus and ammonia and may prevent anoxia in the deeper parts of the lake. However, long-term oxygenation is required and it is uncertain whether the overall lake water quality can be improved by oxygenation. Reduction of the external nutrient loading is still essential to improve lake water quality. Handling editor: Luigi Naselli-Flores     

Lymphocytic Choriomeningitis Virus RNAs

IT has been proposed that lymphocytic choriomeningitis (LCM) virus and immunologically related viruses should be placed in a new taxonomic group, with LCM virus as the prototype virus^1,2. They were called arenoviruses because they contain, as a unique feature, electron-dense, sand-like or ribo-some-like granules². The LCM virus contains RNA and we have previously reported that this RNA can be separated into three components by density gradient centrifugation³.     

Nucleic acid staining with the methyl green-pyronin method. A comparison of the use of pure dyes and commercially available dyes

We compared the staining obtained using commercially available pyronin Y samples with that obtained using pure pyronin Y in a standardized methyl green-pyronin procedure. In addition, the importance of the dye content of the anhydrous dye was investigated by varying the dye content by the addition of pure pyronin Y to one of the commercially available pyronin Y samples. We found that, for routine histological work, commercially available pyronin Y samples may produce acceptable results provided the sample can be shown by spectrophotometry to contain at least 43% pyronin Y.     

Flow cytometric classification of biopsy specimens from cervical intraepithelial neoplasia

The distribution of single-cell DNA content was investigated in biopsy specimens from the human cervix of 121 women suspected of having intraepithelial neoplasia. Comparison of the results of the histopathological examination with the ploidy level showed that all normal specimens were diploid. Thus, no false-positive results occurred. Most of the specimens classified as mild and moderate dysplasia were diploid as well. Aneuploid cell populations occurred in 78% of the lesions classified as severe dysplasia and carcinoma in situ. The ploidy level distribution permitted a natural division of the aneuploid cell populations into two groups with DNA indices either above or below 1.5. The importance of the aneuploidy in carcinogenesis is discussed.     

Characterization of ploidy level in bladder tumors and selected site specimens by flow cytometry

The histopathological grade of atypia was compared with the ploidy level in biopsy specimens from bladder tumors and six grossly normal areas (selected sites). The study included investigation of 303 specimens from 45 patients. The results demonstrated a high correlation between the grade of atypia and the occurrence of aneuploid cell populations. The selected site specimens were diploid in patients with low grade malignant tumors, while high grade malignant tumors were associated with aneuploid selected site specimens in 20% of the cases. The divergence of ploidy level in the tumor and selected site specimens found in some cases clearly demonstrated that the carcinogenic process in the bladder may lead to clonal heterogeneity. Flow cytometric analysis seems suited for mapping of the ploidy levels in different parts of the bladder. The possible importance of the additional information is discussed.     

Loss of cellular immune reactivity during acute Plasmodium falciparum malaria

Sixteen patients suffering from acute Plasmodium falciparum malaria were studied. All were residents of an area of unstable malaria-transmission in Eastern Sudan. Blood-samples were drawn at diagnosis, and 7 and 30 days later. Blood-samples from thirteen donors, drawn outside the malaria transmission season 5 months prior to the attack, were included in the study. Lymphoproliferative responsiveness to purified soluble malarial antigens and to the unrelated antigen PPD was lost during the acute phase of the disease in most donors, but was regained during convalescence, except in four donors recrudescing or reinfected by day 30. In contrast to the suppression of antigenic responses, cellular responses to phytohaemagglutinin (PHA) remained virtually unaffected. All donors showed elevated plasma-levels of soluble IL-2 receptor during the acute phase of the disease which normalized during convalescence. Five donors examined by fluorescence-activated cell sorting (FACS) showed no increase in surface expression of IL-2 receptor on peripheral lymphocytes. The data indicate that acute P. falciparum malaria causes a depletion of antigen-reactive T-cells from the peripheral circulation, probably due to homing of this cell-population to lymphoid tissues. It was also found that acute-phase plasma was suppressive to PPD-induced proliferative responses, indicating an additional suppressive mechanism operating in vivo.     

Correlation of DNA distribution and cytological differentiation of human cervical carcinomas

The DNA distribution of biopsy specimens from 46 patients suffering from cervical carcinoma was analysed by flow cytometry and compared with the cytological differentiation. According to morphological criteria the carcinomas were classified as highly differentiated, moderately differentiated and poorly differentiated. The results demonstrate that highly differentiated tumours contain hyperploid cells predominantly with hyperdiploid DNA content. Hyperploid cell populations in the moderately differentiated tumours are mainly in the hyperdiploid and tetraploid regions. Poorly differentiated tumours contain hypertetraploid and aneuploid cell populations. The significance of these findings is discussed.