Relevance of HIV-1-specific CD4+ helper T-cell responses during structured treatment interruptions in patients with CD4+ T-cell nadir above 400/mm3

OBJECTIVES: To analyze the dynamics of both HIV-1-specific CD4 and CD8 T-cell responses during structured treatment interruptions (STIs) in chronically HIV-1-infected (CHI) patients and to correlate them with the viral set point achieved. METHODS: Forty-five early-stage CHI patients who were on highly active antiretroviral therapy (HAART) for at least 1 year and underwent STI were included. Plasma viral load (VL), peripheral blood mononuclear cell (PBMC) lymphoproliferative (LPR) response to HIV p24 protein, and HIV-1 epitope-specific interferon-gammarelease from CD8 T cells were measured over a minimum study period of 2 years. RESULTS: VL set point during final STI was both significantly lower than, and positively correlated to, baseline VL (P < 0.0001: mean VL reduction 0.77 log10, and r = 0.42, P = 0.004, respectively). CD4 LPRs to p24 increased significantly (P = 0.001) between day 0 of the first STI cycle and 4th STI but decreased thereafter. VL set point during final STI was significantly and negatively correlated with LPRs to p24 at both 2nd STI and 4th STI. Nevertheless, at week 52, 12 weeks after the end of the last STI, LPRs were weak and transient in all patients and were not correlated with VL set point. Moreover, the magnitude and breadth of HIV-1-specific CD8 T-cell responses increased significantly (P < 0.0001) between day 0 and week 52. The largest increases occurred during the final STI. Even though VL reached set point by week 12 of the final STI, HIV-1-specific CD8 T-cell responses did not stabilize but rather increased until the end of the follow-up and did not correlate with plasma VL (r = 0.01, P = 0.88). CONCLUSIONS: STIs do not lead to control of viral replication in CHI patients, probably due to the fact that boosted CTL responses lack strong and durable helper T-cell responses. To reset the VL set point, new approaches that effectively augment and preserve helper T-cell responses should be investigated.     

ErbB2 and the antimetastatic nm23/NDP kinase in regulating serum induced breast cancer invasion

The erbB2 gene is often found amplified and/or overexpressed in breast cancer in which it has clinical relevance as prognostic and predictive factor. It is involved in growth regulation and has a role in the initial phases of cell proliferation, while in vivo and in vitro studies have suggested an involvement also in cell invasion and metastases. It is not clear if these two roles are mutually exclusive and little is known about the mechanisms by which erbB2 may be involved in the control of these processes. Our previous data on patient series suggested that erbB2 might be regulated in different ways depending on the neoplastic status of the cells and that it might be involved in different regulatory pathways. To test this hypothesis we have measured the serum-dependent regulation of erbB2 as a function of the expression of the antimetastatic gene, nm23, in a panel of breast cancer cell lines. The experimental model consisted of three cell lines having different proliferative and invasive potentials: a non-metastatic estrogen receptor (ER) positive cell line, MCF-7; a highly metastatic ER negative cell line, MDA-MB435; and the MDA-MB435 cell line transfected with the nm23-H1 antimetastatic gene (clone H1-177) which has lost the ability to invade and metastasize. We first analysed the serum concentration dependence of invasion and proliferation after 3-4 days of serum deprivation confirming the proliferative and invasive potential of the three cell lines. Modulation of erbB2 expression by different concentrations of serum was then studied. ErbB2 expression in MCF-7 cells showed a complex pattern due to serum modulation, whereas, it was not longer regulated by serum in the MDA-MB435 cell line. In H1-177 cells the erbB2 response to serum was restored and it was very similar to that observed in MCF-7. These data showed a tight association between nm23 and the regulation of erbB2 expression by serum factors suggesting that the role of erbB2 in invasion might be dependent on nm23 expression.     

Estimates of global research productivity in virology

The quantity and quality of published research in the field of Virology by different world regions was estimated in this study. Using the PubMed database, articles from journals included in the "Virology" category of the "Journal Citation Reports" database of the Institute for Scientific Information for the period 1995-2003 were retrieved. The world was divided into nine regions based on geographic, economic, and scientific criteria. Data on the country of origin of the research was available for 33,425 out of 33,712 articles (99.2% of all articles from the included journals). USA exceeds all other world regions in research production for the period studied (42% of total articles), with Western Europe ranking second (35.7%). The mean impact factor in articles published in Virology journals was highest for the USA (4.60), while it was 3.90 for Western Europe and 3.22 for the rest of the world (seven regions combined). USA and Canada ranked first in research productivity when both gross national income per capita (GNIPC) and population were taken into account. The results of this analysis show a distressing fact; the absolute and relative production of research in the field of Virology by the developing regions is very low, although viral diseases cause considerable morbidity and mortality in these areas. It is evident from this study that developing regions need more help from the developed regions to enhance research infrastructure.     

Morphological features in human cortical brain microvessels after head injury: a three-dimensional and immunocytochemical study

We studied the morphology of cortical microvessels in the brains of 10 patients who had died after receiving a traumatic head injury (THI). Scanning electron microscopy (SEM) of vascular corrosion casts, confocal microscopy of histological sections after immunocytochemistry, and detection of apoptosis by terminal dUTP nick end labeling (TUNEL) were used. Microvascular casts showed an angioarchitectonic distribution that was defined as normal according to results obtained in a previous, nontraumatic series of subjects. However, when we compared them with previous works, the cast surface of some of the microvessels showed three types of morphological alterations: longitudinal folds, sunken surfaces with craters, and a significant flattening with reduction of lumen. The vessels that were primarily affected were the arterioles and capillaries of the middle and deep cortical vascular zones. Immunostaining with the monoclonal antibody MAS-336 against endothelial cells also showed the presence of longitudinal folds with a thinning of the vascular lumen, cytoplasmic round bodies, and a thickening of the endothelial cell membrane. The TUNEL technique revealed a positive staining of some endothelial cells. The structural alterations we observed indicate that microvessels undergo endothelial cell damage after THI. We suggest that this kind of lesion and the secondary functional injury to the blood-brain barrier (BBB) could play an important role in the development of the secondary lesions that these patients show in the subacute phase.     

Controlling the statistics of action: obstacle avoidance

Task optimization in the presence of signal-dependent noise (TOPS) has been proposed as a general framework for planning goal-directed movements. Within this framework, the motor command is assumed to be corrupted by signal-dependent noise, which leads to a distribution of possible movements. A task can then be equated with optimizing some function of the statistics of this distribution. We found the optimal trajectory for obstacle avoidance by minimizing the mean-squared error at the end of the movement while keeping the probability of collision with the obstacle below a fixed limit. The optimal paths accurately predicted the empirical trajectories. This demonstrates that controlling the statistics of movements in the presence of signal-dependent noise may be a fundamental and unifying principle of goal-directed movements.     

A quantitative ELISA for antigen-specific IgG subclasses using equivalence dilutions of anti-kappa and anti-subclass specific secondary reagents Application to the study of the murine immune response against the capsular polysaccharide of Neisseria meningitidis serogroup B

We have developed an enzyme-linked immunosorbent assay (ELISA) to measure murine antigen-specific IgG antibodies of defined subclass using precalibrated equivalence dilutions of anti-κ (in the standard) and each anti-IgG subclass-specific polyclonal secondary antibody (in the test sample). The calibration of secondary reagents could be carried out easily with a set of monoclonal antibodies (MoAbs) specific for all IgG subclasses. These MoAbs do not require purification or standardization. In addition the MoAbs can be of different antigenic specificity. Once the equivalence dilutions have been determined, they can be applied in a quantitative ELISA using the same antigen in the standard and sample, and using only one IgG subclass standard for the determination of all the IgG subclasses. The method is easy to standardize for many antigenic systems. It is particularly useful when the only standard available is one standardized MoAb of the appropriate specificity, and it could be adapted to use with standard polyclonal antibodies having a known content of total antigen-specific IgG bearing κ chains but unknown IgG subclass composition. The use of this method to quantitate IgG specific for the capsular polysaccharide of Neisseria meningitidis serogroup B (CpsB) gave highly reproducible measures with an interbatch CV of 5–6% similar for all IgG subclasses and low detection limits ranging from 0.3 ng/well for IgG3 to 0.8 ng/well for IgG2a. The IgG subclass response observed after immunization with live meningococci was mainly IgG2a (74%) and IgG2b (18%). Hyperimmunization modified this IgG distribution to one of mainly IgG3 (62%) and IgG1 (28%) which was maintained in the response to a single immunization 4 weeks later, possibly indicating the generation of resting B cells during continuous stimulation.     

Diagnosis of Ovarian Cancer Using Decision Tree Classification of Mass Spectral Data

Recent reports from our laboratory and others support the SELDI ProteinChip technology as a potential clinical diagnostic tool when combined with $n$ -dimensional analyses algorithms. The objective of this study was to determine if the commercially available classification algorithm biomarker patterns software (BPS), which is based on a classification and regression tree (CART), would be effective in discriminating ovarian cancer from benign diseases and healthy controls. Serum protein mass spectrum profiles from 139 patients with either ovarian cancer, benign pelvic diseases, or healthy women were analyzed using the BPS software. A decision tree, using five protein peaks resulted in an accuracy of 81.5% in the cross-validation analysis and 80%in a blinded set of samples in differentiating the ovarian cancer from the control groups. The potential, advantages, and drawbacks of the BPS system as a bioinformatic tool for the analysis of the SELDI high-dimensional proteomic data are discussed.     

Circulating antibodies to peripheral nerve in American trypanosomiasis (Chagas' disease).

An antibody reacting with Schwann sheaths of myelinated somatic and unmyelinated autonomic peripheral nerve was found in sixty-one out of seventy-one chronic, and nine out of ten acute, Chagas' disease sera. Indirect immunofluorescence (IFL) was carried out on rat, mouse and human somatic nerves and rat sympathetic nerves with initial serum dilutions of 1 : 10, and the staining reached a final titre of 1 : 320 in some cases. The antibodies fixed complement and were absorbed out by lyophilized epimastigotes of T. cruzi. Lipid extraction of the tissue sections enhanced the staining of myelinated nerve, whereas unfixed unmyelinated sympathetic nerve was strongly reactive. Central nervous tissue did not display any positive staining on neurons, glial cells or periaxonal sheaths. Furthermore, by using a double-labelled IFL technique, it was possible to show that a rabbit antiserum raised against guinea-pig spinal cord and the chagasic anti-nerve antibodies reacted with different structures in the rat sciatic nerve. These findings suggest that the reactive antigen(s) could be located on Schwann cells. The majority, but not all, of the chagasic individuals with anti-nerve antibodies also showed the sarcolemmal and endothelial staining (EVI) previously described in Chagas' disease. The possible recognition of Schwann cell antigens by circulating antibodies in Chagas' disease could be relevant, since an autonomic denervation has been postulated as a pathogenic mechanism of cardiomyopathy and megaviscera in this condition.