Activation of apoptosis associated with enforced myc expression in myeloid progenitor cells is dominant to the suppression of apoptosis by interleukin-3 or erythropoietin

The inappropriate expression of c-myc in cells deprived of growth factors has recently been implicated in the activation of programmed cell death (apoptosis). The studies described here examine the ability of interleukin-3 (IL-3) or erythropoietin (Epo) to suppress apoptosis that occurs in association with enforced myc expression during cell cycle arrest of a murine IL-3-dependent myeloid progenitor cell line, 32D. G1 arrest was observed when culturing 32D cells to high density in medium supplemented with IL-3, or at subconfluent densities in medium supplemented with Epo. Under both conditions, endogenous c-myc expression was downregulated and viability was maintained. In clones of cells in which c-myc is constitutively expressed from a retroviral vector, enforced c-myc expression was associated with the activation of apoptosis at high cell densities. Similarly, enforced c-myc expression was deleterious to cell survival when these cells were cultured in Epo, as apoptosis was evident within 6 hours. The results support the concept that inappropriate c-myc expression activates apoptosis and that neither IL-3 nor Epo can suppress this program under these conditions.     

Impact of health care payer type on HIV stage of illness at time of initiation of antiretroviral therapy in the USA

There is evidence that earlier initiation of HIV antiretroviral therapy (ART) is associated with better outcomes, including lower morbidity and mortality. Based on recent studies indicating that Medicaid enrollees are more likely to have suboptimal access to medical care, we hypothesized that HIV severity at time of ART initiation is worse for Medicaid patients than patients with other health care coverage. We conducted a US retrospective analysis of GE Centricity Outpatient Electronic Medical Records spanning 1 January 1997 through 30 September 2009. Subjects included all adult HIV patients initiating first-line ART who had CD4+ results within 90 days pre-initiation. HIV stage was defined using CD4 ranges: >500 (n=520), 351–500 (n=379), 201–350 (n=580), or ≤200 (n=406) cells/mm³, with lower CD4 count being indicative of increased disease severity. Payer type was defined as the patient's primary payer: Medicaid, Medicare, commercial insurance, self-pay or other/unknown. After controlling for demographic and clinical covariates, cumulative logit models assessed the effect of payer type on HIV stage at ART initiation. The study included 1885 subjects with the primary payer being Medicaid (n=218), Medicare (n=330), commercial insurance (n=538), self-pay (n=159) or other/unknown (n=640). Final logit models demonstrated that, compared to patients on Medicaid, the odds of initiating ART at a higher CD4 range were significantly greater for those commercially insured (odds ratio [OR]=1.53; P=0.005), self-paying (OR=1.56; P=0.023) and other/unknown (OR=1.79; P<0.001) and similar for patients enrolled in Medicare (OR=1.11; P=0.521). Medicaid patients initiated ART at a more advanced stage of HIV than patients who were commercially insured, self-paying, or had other/unknown coverage. With HIV treatment guidelines now supporting ART initiation in patients with higher CD4 counts, these findings underscore the need for mitigating barriers, particularly in the Medicaid population, that may delay treatment initiation.     

长鞭红景天化学成分的研究

长鞭红景天化学成分的研究彭江南，葛永潮，李晓晖（军事医学科学院放射医学研究所，北京１００８５０）红景天是滋补强壮药物，目前正引起人们极大的兴趣，现已有一些产品上市。我们曾对数种红景天的化学成分进行过研究［１～４］。长鞭红景天（Ｒｈｏｄｉｏｌａｆａｓｔ...     

Cardiac tamponade in a preterm neonate secondary to a chest tube

In a preterm infant, chest tubes were inserted for treatment of bilateral pneumothoraces. Hemorrhagic pericardial effusion with cardiac tamponade developed, probably resulting from traumatic injury by the left chest tube. The infant survived due to timely diagnostic and therapeutic intervention. No recurrence of pericardial effusion was seen and follow-up showed normal psychomotor development.     

Synthesized MR images: comparison with acquired images

Synthesized and directly acquired spin-echo images were compared in order to assess the validity of magnetic resonance (MR) image synthesis as a method enabling retrospective formation of images by interactive manipulation of scan parameters. Synthetic images subjectively compared favorably in both accuracy and precision with acquired images when formed for the same values of echo (TE) and repetition times (TR) and for interpolated and extrapolated values of both TE and TR. Plots of synthetic and acquired signals within the same pixel sectors quantitatively showed comparable values for several regions of interest in the brain. Percent error and noise-normalized differences between acquired and synthetic images were tested as a quantitative measure of accuracy. Percent error was consistently less than 5% for brain parenchyma, and synthetic signals were accurate to within four times the noise level at acquisition. The apparent signal-to-noise ratio of synthetic images was comparable, superior, or inferior to similar acquired images, depending on the values of TE and TR. Total acquisition time required for synthetic formation of images for arbitrary values of TE and TR was equivalent to that of a single direct acquisition with a TR of 2,500 msec.