Low T cell reactivity to combined CD3 plus CD28 stimulation is predictive for progression to AIDS: correlation with decreased CD28 expression

In 219 HIV-1-infected men of the Amsterdam cohort we measured CD4+ T cell numbers and in vitro T cell responses to CD3 MoAbs with or without CD28 costimulation and phytohaemagglutinin (PHA). The value of these markers was estimated for disease progression within 4 years. CD28 expression on T cells has been related to T cell responses. CD28 costimulation considerably enhanced T cell reactivity (approximately 8-10-fold) with lower coefficients of variation compared with reactivity to CD3 MoAb alone (median 5 versus 20). T cell reactivity to CD3 plus CD28 MoAb was decreased during HIV-1 infection and was besides CD4+ T cell numbers the only independent predictor for progression to AIDS. Compared with the group with high CD4+ T cell numbers the relative risk (RR) for the group with intermediate levels was 2.28, with low levels 5.20. In the groups with intermediate and low CD3 plus CD28 responses the RR was 2.04 and 4.16, respectively. The combined RR for both was 4.65 and 21.63. The independence of this marker was confirmed when the group with low CD4+ T cell numbers was subdivided into groups with high, intermediate and low T cell responses. The expansion of CD8+CD28- T cells was already apparent in HIV- homosexual men, but CD8+CD28+ T cells specifically decreased in patients with AIDS. CD28 expression on T cells correlated moderately with T cell responses to CD3 plus CD28 MoAb. T cell reactivity to CD3 MoAb in the presence of CD28 MoAb is a stronger prognostic marker than T cell reactivity to CD3 MoAb alone.     

Characterisation of a novel Drosophila melanogaster testis specific PP1 inhibitor related to mammalian inhibitor-2: identification of the site of interaction with PP1

Paralytic shellfish poisoning (PSP) toxins are produced by certain dinoflagellate species such as Gymnodinium catenatum and Alexandrium tamarensis, during certain periods of the year influenced by several environmental factors, affecting the aquaculture industry and mainly bivalve molluscs. HPLC with fluorescence detection is a powerful analytical technique for the analysis of such toxins; several HPLC alternatives have been developed in order to improve the liquid chromatographic analysis, but due to the complexity of the sample matrix, important work has been focused recently on the clean-up of samples prior to HPLC analysis. Solid-phase extraction procedures offer advantages for this clean-up. In this work we focus on the study of three different clean-up methods prior to HPLC with fluorescence detection analysis of PSP toxin present in contaminated mussel samples; by spiking uncontaminated mussel samples with two different PSP toxin standards and by calculating the recovery values for these experiments. These recoveries must be taken into account in order to quantify the exact amount of PSP toxins present in the contaminated samples.     

Anomalous right coronary artery from the pulmonary artery in Taussig-Bing anomaly

The presence of associated anomalies in patients with double-outlet right ventricle can significantly alter surgical intervention. Preoperative delineation of these anomalies can facilitate surgical planning and improve outcome. We describe a case in which the right coronary artery and anterior descending coronary artery arose from the pulmonary artery in a patient with double-outlet right ventricle with subpulmonary ventricular septal defect (Taussig-Bing anomaly). Recognition of this important anomaly prevented significant intraoperative myocardial damage by altering techniques of cardioplegia administration for myocardial preservation.     

Mathematical models for motile bacterial transport in cylindrical tubes

Mathematical models considering motile bacterial transport within a geometrically restrictive cylindrical tube were developed. Two macroscopic transport parameters, the random motility coefficient as a self-diffusion coefficient of the cell population and the chemotactic velocity as a chemical-induced velocity, were derived. The three-dimensional cell balance equation was reduced to forms similar to Segel's one-dimensional phenomenological cell balance equations with additional modifications for bacteria-wall interactions. Two conceptually different approaches accounting for such interactions were presented. The first approach parallels treatments in the gas kinetic theory by viewing bacterial interactions with walls as collisions and subsequent diffusive/specular reflections, which led to the Bosanquet formula for the bacterial diffusion coefficient. Based on the experimental observation that bacterial swimming motion is guided by a straight tube, the second approach considered modifications in the bacterial swimming orientation as a consequence of various long-range interactions with the tube surface. A phenomenological turning model capable of aligning bacterial motion along a tube axis was proposed. The model predicts that under the geometrical restriction of a small cylindrical tube, the macroscopic bacterial transport resulting from the proposed turning model can exhibit behavior that ranges from dimensionally reduced diffusion to pure wave propagation, depending on the influence of the tube diameter on the reversal probability in the bacterial swimming motion. Our theoretical model provides explicit equations that explain how such a transition can occur. The predicted results were then qualitatively compared with experimental data from the literature. As a preliminary comparison, we concluded that bacterial transport in cylindrical tubes of diameter 10 micrometers remains in the mode of a dimensionally reduced diffusion, and shifts to a wave motion when the tube diameter decreases to 6 micrometers.     

Infertility profile at King Edward VIII Hospital, Durban, South Africa

Interventional MRI is one of the most recent developments of clinical MR imaging. Because of the development of open MR systems and very compact high-field systems, a number of interventional procedures are already possible today under MR control and will be tested in experimental and clinical investigations. The currently commercially available systems differ with respect to their static magnetic field strength, their gradient systems and patient access. In addition, there are differences concerning their space requirements and costs. All systems have components facilitating interventional procedures. In this article we discuss the advantages and shortcomings of these commercially available systems and look at future developments in interventional MR equipment.     

Liver failure associated with mitochondrial DNA depletion

BACKGROUND/AIMS: Liver failure in infancy can result from several disorders of the mitochondrial respiratory chain. In some patients, levels of mitochondrial DNA are markedly reduced, a phenomenon referred to as mitochondrial DNA depletion. To facilitate diagnosis of this condition, we have reviewed the clinical and pathological features in five patients with mitochondrial DNA depletion. METHODS: Cases were identified by preparing Southern blots of DNA from muscle and liver, hybridising with appropriate probes and quantifying mitochondrial DNA relative to nuclear DNA. RESULTS: All our patients with mitochondrial DNA depletion died of liver failure. Other problems included hypotonia, hypoglycaemia, neurological abnormalities (including Leigh syndrome) and cataracts. Liver histology showed geographic areas of fatty change, bile duct proliferation, collapse of liver architecture and fibrosis; some cells showed decreased cytochrome oxidase activity. Muscle from three patients showed mitochondrial proliferation, with loss of cytochrome oxidase activity in some fibres but not in others; in these cases, muscle mitochondrial DNA levels were less than 5% of the median control value. The remaining two patients (from a single pedigree) had normal muscle histology and histochemistry associated with less severe depletion of mitochondrial DNA in muscle. CONCLUSIONS: Liver failure is common in patients with mitochondrial DNA depletion. Associated clinical features often include neuromuscular disease. Liver and muscle histology can be helpful in making the diagnosis. Mitochondrial DNA levels should be measured whenever liver failure is thought to have resulted from respiratory chain disease.     

Pollutant transport during a regional O3-episode in the mid-Atlantic states

Ozone (O3) concentrations in the Baltimore-Washington (B-W) metropolitan area frequently exceed the National Ambient Air Quality Standard (NAAQS) in the summer months. The most extreme O3 events occur in multi-day high O3 episodes. These events can be regional in scale, with O3 concentrations exceeding the NAAQS at numerous locations along the eastern U.S. seaboard, and are typically associated with slow-moving or stagnant high pressure systems. In the B-W region, the most extreme events typically occur with surface high pressure overhead or just west of the region and an upper air high-pressure area (ridge) to the west or northwest. Besides providing conditions conductive to local O3 production (subsidence and strong low-level inversions, weak horizontal winds, little cloud cover), this weather pattern may also result in transport of O3 and its precursors from heavily industrialized areas west and north of the B-W region. In this paper, observations and back trajectories made during the severe regional O3 event of July 12-15, 1995, are used to confirm the hypothesis that significant regional-scale transport of O3 and its precursors occur during extreme O3 events of the standard type in the B-W area.     

CSF testosterone and 5-HIAA correlate with different types of aggressive behaviors

We studied the potential roles of testosterone and serotonin in various forms of aggressive and violent behaviors by measuring each biochemical and behaviour in free-ranging adolescent male nonhuman primates. Our results showed that (1) CSF free testosterone concentrations were positively correlated with overall aggressiveness, but not with measures of impulsivity. (2) CSF 5-HIAA concentrations were negatively correlated with impulsive behavior, and severe, unrestrained aggression, but not with overall rates of aggression. High rates of impulsive behavior were positively correlated with severe, unrestrained aggression, but not overall rates of aggression. (3) Dimensional analyses showed that while subjects with low CSF 5-HIAA exhibited high rates of aggression, high CSF testosterone further augmented rates and intensity of aggression in subjects with low CSF 5-HIAA. We conclude that high CSF free testosterone concentrations are associated with competitive aggression, while low CSF 5-HIAA concentrations are associated with severe aggression which results from impaired impulse control, and perseverance.