Purified murine hematopoietic stem cells function longer on nonirradiated W41/Wv than on +/+ irradiated stroma

Mouse bone marrow (BM) was separated into low-density, lineage- negative, wheat germ agglutinin-positive (WGA+), Rhodamine-123 bright (Rhbright) or dim (Rhdim) cells to obtain populations that were highly enriched for committed progenitors (Rhbright cells) or for more primitive stem cells (Rhdim). When 2,500 Rhbright or Rhdim cells were seeded onto 6-week-old irradiated (20 Gy) long-term BM cultures (LTBMC), the nonadherent cell production from Rhbright cells was transient and ended after 5 weeks. Production from Rhdim cells did not begin until week 3, peaked at week 5, and ended at week 8, when the irradiated stroma seemed to fail. Termination of cell production from Rhdim cells did not occur in nonirradiated LTBMC from W41/Wv mice. During peak nonadherent cell production, 25% to 30% of the cells in the nonirradiated LTBMC from W41/Wv mice had donor cell markers. Two approaches were tested to try to enhance the proportion or number of donor cells. Addition of Origen-HGF at the time of seeding Rhdim cells caused a nonspecific increase in both host and donor cell production, but a specific increase in production of donor cells was obtained by seeding the cultures at 2 weeks rather than 6 weeks. Limiting dilution of Rhdim cells gave the same frequency of wells producing cells on both irradiated +/+ and nonirradiated W41/Wv or W/Wv cultures.     

Both long-term HIV infection and highly active antiretroviral therapy are independent risk factors for early carotid atherosclerosis

ObjectiveThere is controversy over whether or not chronic HIV infection contributes to atherosclerosis. We investigated the relationship between HIV infection, antiretroviral medication and ultrasound evidence of early atherosclerosis in the context of vascular risk factors.DesignA case–control design with 292 HIV-positive subjects and 1168 age- and sex-matched controls.MethodsWe assessed vascular risk factors, blood pressure, serum lipids and carotid intima media thickness (IMT) in cases and controls. With multivariate regression models, we investigated the effects of HIV status and antiretroviral medication on IMT.ResultsThe common carotid artery (CCA) IMT value was 5.70% (95% confidence interval [3.08–8.38%], p < 0.0001) or 0.044 mm [0.021–0.066 mm] (p = 0.0001) higher in HIV-positives, adjusted for multiple risk factors. In the carotid bifurcation (BIF), the IMT values were 24.4% [19.5–29.4%] or 0.250 mm [0.198–0.303 mm] higher in HIV patients (p < 0.0001). An investigation of antiretroviral substances revealed higher CCA- and BIF-IMT values in patients receiving combination antiretroviral therapy (HAART).ConclusionsHIV infection and HAART are independent risk factors for early carotid atherosclerosis. Assuming a risk ratio similar to that in large population-based cohorts, the observed IMT elevation suggests that vascular risk is 4–14% greater and the “vascular age” 4–5 years higher in HIV-positive subjects. The underlying mechanisms remain to be clarified.     

Xanthogranulomatous Appendicitis - An Incidental Finding of Localized Pathology

The clinical, histopathological, and electron microscopic features of an unusual case of xanthogranulomatous appendicitis are reported. The patient, a 37-year-old female, presented with typical signs of acute appendicitis and the appendix appeared slightly dilated at laparatomy. The histopathological sections showed numerous xanthoma cells mixed with inspissated fecaliths. Electron microscopy disclosed the presence of xanthoma cells filled with electron-lucent lipid droplets of variable size. The ultrastructural characteristics of these cells enabled the distinction of two types of lipid-laden histiocytes, in relationship to the size of the lipid droplets. Since the lipid droplets were seen also in cells other than histiocytes, it appears that these changes are secondary to a common mechanism,comprising factors such as obstruction, hemorrhage, inflammation,and local hypoxia.     

Impact of HIV-1 replication on immunological evolution during long-term dual-boosted protease inhibitor therapy

To explore CD4-cell and viral evolution in relation to different levels of HIV-1 replication, as observed during protease inhibitor (PI)-based antiretroviral therapy. Adult HIV-1 infected cohort patients, receiving historical salvage therapy with daily doses of saquinavir (2,000 mg), ritonavir (200 mg) and either lopinavir (800 mg) or atazanavir (300 mg) for >36 weeks were retrospectively analysed for highest detectable viral load up to week 96 and assigned to groups according to the viral load level: always <50 copies/ml (1), 50–199 copies/ml (2), 200–499 copies/ml (3) and ≥500 copies/ml (4). A total of 126 patients were evaluated; at baseline, median CD4-cell count was 204/mm³, HIV-1 RNA was 5.13 Log10-copies/ml and duration of prior HIV-1 infection was 11.7 years. Patients were assigned by 43, 30, 7 and 20 % to groups 1–4. Median observation time was 136 weeks (range: 38–304); at weeks 48/96, the CD4-cell gains for groups 1–4 were +88/+209, +209/+349, +67/+300 and +114.5/+ 128, respectively. After fitting data in a linear fixed effect model, ascending CD4 slopes were continuously increasing for group 1, similarly for 2 and clearly decreasing for 3–4 (p = 0.0006). Of 25 individuals from group 4, patient number with major IAS-USA protease mutations increased from 5 to 10 before and after failing PI therapy, whereas minor mutations remained stable (n = 18). On double-boosted PI therapy, CD4-cell increases through week 96 were similar for patients at always undetectable or with detection of low viral load. Viral detection >200 copies/ml was associated with decreasing CD4-cell slopes and emergence of major mutations, supporting this as benchmark for virological failure definition on PI therapy.     

Differential regulation of colony-stimulating factors and interleukin 2 production by cyclosporin A.

Stimulation of T lymphocytes with mitogens or antigens is followed by proliferation and lymphokine production. Although cyclosporin A (CsA), an immunosuppressive drug, has been shown to inhibit the production of certain lymphokines, including interleukin 2 (IL-2), interleukin 3 (IL-3), and gamma-interferon, its effect on the production of granulocyte/macrophage colony-stimulating factor (GM-CSF) has not been evaluated. In the current study, concanavalin A (Con A)-stimulated murine spleen cells secreted GM-CSF, IL-3, and IL-2, and in the presence of CsA (0.1-1.0 micrograms/ml), IL-2 and IL-3 activities were inhibited. In contrast, significant activity was detected when the CsA-treated culture supernatants were assayed on a cell line that is dependent on GM-CSF and/or IL-3. Similar CsA-resistant activity was observed when the EL-4 thymoma cells were stimulated with a phorbol ester [phorbol 12-myristate 13-acetate (PMA)] in the presence of CsA. The activity resistant to CsA was identified as GM-CSF by the ability of specific antibodies against murine recombinant GM-CSF to neutralize its activity. These findings indicate that GM-CSF, in contrast to IL-2 and IL-3, was not inhibited by CsA. In additional experiments, transfer blot of poly(A)+ RNA isolated from PMA-induced EL-4 cells in the presence or the absence of CsA was hybridized with GM-CSF and IL-2 cDNA probes. Expression of the GM-CSF gene in EL-4 cells was detected independent of CsA, whereas CsA inhibited the expression of the IL-2 gene. The present data show that production of IL-2 and IL-3, but not that of GM-CSF, is inhibited by CsA and suggest a differential control mechanism for lymphokine synthesis in T lymphocytes.     

Influence of impaired fasting glucose on the incidence and prognosis of atherosclerosis in various vascular regions

Patients with cardiovascular disease have a poorer diagnosis if they are diabetic. The risk for cardiovascular events is already increased in individuals with impaired fasting glucose (IFG). The aim of this study was to evaluate the impact of diabetes mellitus (DM) and IFG on the incidence of atherosclerotic manifestations and on the long-term prognosis of patients with atherosclerosis in various vascular regions. METHODS: In a prospective study we included 906 patients (72.5% men, mean age 62 +/- 9 years) preceding heart catheterization. All patients were evaluated for the presence of peripheral stenosis by carotid duplex sonography (pathologic: stenosis >50%) and evaluation of the ankle-brachial index (pathologic <0.9). Blood samples were drawn from each subject after an overnight fasting period and serum glucose was evaluated. RESULTS: Patients were compared with regard to the presence of DM (known DMor fasting glucose > or =126 mg/dL, N = 283, 31.2%) or IFG (fasting glucose >110 and <126 mg/dL, N = 89, 9.8%). Patients with IFG and DM had a higher prevalence of atherosclerotic manifestations in the coronary, carotid and peripheral vessels. Diabetics had the highest prevalence of atherosclerotic manifestations in multiple vascular regions (=advanced atherosclerosis). Cardiovascular events (death, myocardial infarction and stroke) after a median follow-up of 4.1 years were evaluated in 901 patients (99.4%). Presence of IFG and DM significantly increased the incidence of cardiovascular events (event rate: no DM 10.9%, IFG 13.6%, DM 23.4%, P < 0.0001). Moreover, patients with advanced atherosclerosis suffered significantly more often from cardiovascular events (event rate: no stenosis 4.1%, coronary artery disease without peripheral stenosis 9.7%, advanced atherosclerosis 23.9%). Prognosis was worst in patients with DM and advanced atherosclerosis with an event rate of 35%.Patients with cardiovascular disease have a poorer prognosis if they are diabetic. The risk for cardiovascular events is already increased in individuals with impaired fasting glucose (IFG). The aim of this study was to evaluate the impact of diabetes mellitus (DM) and IFG on the incidence of atherosclerotic manifestations and on the long-term prognosis of patients with atherosclerosis in various vascular regions.