Differences in Transcriptional Dynamics Between T-cells and Macrophages as Determined by a Three-State Mathematical Model

HIV-1 viral transcription persists in patients despite antiretroviral treatment, potentially due to intermittent HIV-1 LTR activation. While several mathematical models have been explored in the context of LTR-protein interactions, in this work for the first time HIV-1 LTR model featuring repressed, intermediate, and activated LTR states is integrated with generation of long (env) and short (TAR) RNAs and proteins (Tat, Pr55, and p24) in T-cells and macrophages using both cell lines and infected primary cells. This type of extended modeling framework allows us to compare and contrast behavior of these two cell types. We demonstrate that they exhibit unique LTR dynamics, which ultimately results in differences in the magnitude of viral products generated. One of the distinctive features of this work is that it relies on experimental data in reaction rate computations. Two RNA transcription rates from the activated promoter states are fit by comparison of experimental data to model predictions. Fitting to the data also provides estimates for the degradation/exit rates for long and short viral RNA. Our experimentally generated data is in reasonable agreement for the T-cell as well macrophage population and gives strong evidence in support of using the proposed integrated modeling paradigm. Sensitivity analysis performed using Latin hypercube sampling method confirms robustness of the model with respect to small parameter perturbations. Finally, incorporation of a transcription inhibitor (F07#13) into the governing equations demonstrates how the model can be used to assess drug efficacy. Collectively, our model indicates transcriptional differences between latently HIV-1 infected T-cells and macrophages and provides a novel platform to study various transcriptional dynamics leading to latency or activation in numerous cell types and physiological conditions.

[Xenon computerized tomography of kidney transplants]

Xenon-CT is an established method for determining cerebral perfusion, while applications in other organs are rare. We evaluated the diagnostic potential of measuring the regional Renal Blood Flow (rRBF) in 10 patients with transplanted kidneys by xenon-CT. We found significant differences in the rRBF between the renal medulla and the cortex. There were no differences between normal renal transplants and transplants with chronic rejection.

Transient cerebral ischaemic attacks and calcium-magnesium imbalance: clinical and paraclinical findings in 106 patients under 50 years of age

One hundred and six selected patients (71 women, 35 men) suffering from transient cerebral ischaemic attacks (TIA) when aged less than 50 years received a comprehensive diagnostic assessment. Patients were classified into three subgroups, into which 9% could be assigned in approximately equal proportions. These were group A; TIA patients with tetanic syndrome (median age of first TIA 32 years, mainly female, 3.2 attacks per year and changing vascular area); group B; TIA patients with migraine (median age of first TIA 26 years, no predominance of male or female sex, 2.0 attacks per year and mostly in the same vascular area); group C: TIA patients suffering from premature arteriosclerosis (median age of first TIA 40 years, no predominance of male or female sex. 0.8 attacks per year and mostly in the same vascular area). Magnesium (P less than 0.001) and calcium (P less than 0.05) in plasma were reduced in group A, and magnesium (P less than 0.05) in group B, versus group C. The increased propensity to vasoconstriction appears to be an important pathogenic factor, particularly in group A, but also in group B.

[Computerized tomography and infusion test as a simultaneous study method in post-traumatic hydrocephalus]

The cerebral compression of a patient with posttraumatic hydrocephalus was measured intraventricularly, and an intrathecas infusion test was made simultaneously with computed tomography. Substractive computed tomography pictures show that continuously increasing volume does not imply uniform enlargement of the ventricular system, the cornua of the lateral ventricles in particular exhibiting a frontal increase in size.