Increased thrombogenic potential of human monocyte-derived macrophages spontaneously transformed into foam cells

This study investigated whether spontaneous lipid enrichment of human macrophages affects their thrombogenic potential as measured by increased production of tissue factor (TF) and plasminogen activation inhibitor types 1 and 2 (PAI-1 and PAI-2). Macrophages were obtained following a 7-day culture period of monocytes, isolated from the same donor, in autologous serum (HS) or in fetal bovine serum (FBS). Those cultured in HS underwent marked lipid accumulation relative to those cultured in FBS that was accompanied by increased production of TF and PAI-1, but not of PAI-2, and decreased production of interleukin-1beta. They also contained more arachidonic and linoleic acid and lower amounts of n-3 polyunsaturated fatty acids, particularly docosahexaenoic acid (22: 6). These data indicate that the transformation of macrophages into foam cells results in an increase in their thrombogenic and antifibrinolytic potential and provide a possible explanation of the thrombotic sequelae frequently consequent on plaque fissuring and disruption.     

F-actin levels but not actin polymerization are affected by triphenyltin in HL-60 cells

The toxin triphenyl tin (TPT), Sn(C(6)H(5))(+)(3) caused a rapid decrease in the F-actin content of promyelocytic human leukemia cells (HL-60) chemically differentiated to neutrophils. Prior incubation (2 min) of the cells with 10 μM TPT did not modify the extent of actin polymerization inducible either by a receptor-mediated stimulus (chemotactic peptide fMLP) or by a direct activator of G proteins (AlF(-)(4)). The inorganic tin salts SnCl(2) and SnCl(4) did not affect F-actin content or production of HL-60 cells. Microfilament thiol groups were not reduced by exposure of cells to TPT, but even increased. When F-actin was exposed to 10 |GmM triphenyltin in a cell-free system, the depolymerizing effect was not detectable. Thus, TPT does not affect cytoskeletal protein directly but depends for its toxicity on some other induced change, probably ionic/osmotic in the intact cell.     

Presence of functionally active β-adrenoceptors in rat mast cells

Summary The correlation between the binding of a -adrenoceptor antagonist, (–)[³H]-dihydroalprenolol (DHAP), and the adrenergic inhibition of histamine release by acetylcholine and by compound 48/80 was studied with isolated purified rat mast cells and in rat mast cell crude membrane fractions.Acetylcholine-evoked histamine release was inhibited by catecholamines, in the order isoprenaline > adrenaline > noradrenaline. Pretreatment of cells with (–)alprenolol antagonized the inhibitory effect of isoprenaline on acetylcholine-induced histamine release.40/80-evoked histamine release was bocked by isoprenaline at significantly higher concentrations than those required to inhibit cholinergic histamine release. The inhibitory effect of isoprenaline was equally antagonized by preincubating mast cells with (–)alprenolol.Specific binding sites for DHAP have been demonstrated in rat mast cell membranes. The specific binding of DHAP was inhibited by adrenoceptor agonists and antagonists according to the stereospecificity of these compounds.A close correlation between the binding-inhibitory potency of various adrenergic compounds and the data obtained in the pharmacological experiments was found, thus indicating the presence of -adrenoceptors in rat mast cells.     

Diagnostic reliability of scintigraphy in hepatic metastases of breast cancer

The authors have reviewed their experiences in determining the presence of liver metastases in 103 patients by radiocolloid scanning. The sensitivity of liver scanning proved to be quite low if the presence of focal defects of tracer's distribution was chosen as the diagnostic criterion. The inclusion of less restrictive criteria, such as liver enlargement or irregular distribution of the tracer, resulted in an higher sensitivity without lowering the predictive value of a negative scan. Using the more extensive diagnostic criterion, sensitivity, specificity and accuracy were in the range of 90%. Abnormal liver scans are common in patients classified as T3-T4 or N+ and their chances of to be "true positives" are high. Conversely, abnormal scans are seldom found in patients classified as T1-T2 or N0 and chances of "false positives" are high.     

Imatinib inhibits proliferation of Ewing tumor cells mediated by the stem cell factor/KIT receptor pathway, and sensitizes cells to vincristine and doxorubicin-induced apoptosis.

PURPOSE AND EXPERIMENTAL DESIGN: The stem cell factor/KIT receptor loop may represent a novel target for molecular-based therapies of Ewing tumor. We analyzed the in vitro impact of KIT blockade by imatinib in Ewing tumor cell lines. RESULTS: KIT expression was detected in 4 of 4 Ewing tumor cell lines and in 49 of 110 patient samples (44.5%) by immunohistochemistry and/or Western blot analysis. KIT expression was stronger in Ewing tumors showing EWS-FLI1 nontype 1 fusions. Despite absence of c-kit mutations, constitutive and ligand-inducible phosphorylation of KIT was found in all tumor cell lines, indicating an active receptor. Treatment with KIT tyrosine kinase inhibitor imatinib (0.5-20 micro M) induced down-regulation of KIT phosphorylation and dose response inhibition of cell proliferation (IC(50), 12-15 micro M). However, imatinib administered alone at doses close to IC(50) for growth inhibition (10 micro M) did not induce a significant increase in apoptosis. We then analyzed if blockade of KIT loop through imatinib (10 micro M) was able to increase the antitumor in vitro effect of doxorubicin (DXR) and vincristine (VCR), drugs usually used in Ewing tumor treatment. Addition of imatinib decreased in 15-20 and 15-36% of the proliferative rate of Ewing tumor cells exposed to DXR and VCR, respectively, and increased in 15 and 30% of the apoptotic rate of Ewing tumor cells exposed to the same drugs. CONCLUSIONS: Inhibition of Ewing tumor cell proliferation by imatinib is mediated through blockade of KIT receptor signaling. Inhibition of KIT increases sensitivity of these cells to DXR and VCR. This study supports a potential role for imatinib in the treatment of Ewing tumor.     

CD34+ cells from acute myeloid leukemia, myelodysplastic syndromes, and normal bone marrow display different apoptosis and drug resistance-associated phenotypes.

Myelodysplastic syndromes and acute myeloid leukemia (AML) are heterogeneous disorders in which conflicting results in apoptosis and multidrug resistance (MDR) have been reported. We have evaluated by multiparameter flow cytometry the expression of apoptosis- (APO2.7, bcl-2, and bax) and MDR-related proteins [P-glycoprotein (P-gp), multidrug resistance protein (MRP), and lung resistance protein (LRP)] specifically on bone marrow (BM) CD34+ cells, and their major CD32-/dim and CD32+ subsets, in de novo AML (n=90), high-risk myelodysplastic syndrome (n=9), and low-risk myelodysplastic syndrome (n=21) patients at diagnosis, and compared with normal BM CD34+ cells (n=6). CD34+ myeloid cells from AML and high-risk myelodysplastic syndrome patients displayed higher expression of bcl-2 (P <0.0001) and lower reactivity for APO2.7 (P=0.002) compared with low-risk myelodysplastic syndrome and normal controls. Similar results applied to the two predefined CD34+ myeloid cell subsets. No significant differences were found in the expression of P-gp, MRP, and LRP between low-risk myelodysplastic syndrome patients and normal BM, but decreased expression of MRP (P <0.03) in AML and high-risk myelodysplastic syndromes and P-gp (P=0.008) in high-risk myelodysplastic syndromes were detected. Hierarchical clustering analysis showed that low-risk myelodysplastic syndrome patients were clustered next to normal BM samples, whereas high-risk myelodysplastic syndromes were clustered together and mixed with the de novo AML patients. In summary, increased resistance to chemotherapy of CD34+ cells from both AML and high-risk myelodysplastic syndromes would be explained more appropriately in terms of an increased antiapoptotic phenotype rather than a MDR phenotype. In low-risk myelodysplastic syndromes abnormally high apoptotic rates would be restricted to the CD34- cell compartments.     

Polyunsaturated fatty acid concentrations in human hindmilk are stable throughout 12-months of lactation and provide a sustained intake to the infant during exclusive breastfeeding: an Italian study

While a wealth of data on the fatty acid composition of mature human milk has been published, limited information is available on the quantities of individual fatty acids supplied to the suckling infant with maternal milk, through the whole first year of life. Our aim was to qualitatively and quantitatively evaluate the fatty acid composition of human milk from Italian mothers, throughout extended lactation with particular emphasis on the long-chain polyunsaturated fatty acids. We have thus measured the total fat content and the concentrations of major fatty acids by quantitative GLC in pooled breast hindmilk collected from all feedings over 24 h at colostrum, 1, 3, 6, 9 and 12 months in ten mothers recruited after delivery of full-term infants. Total saturated fatty acids progressively increase and total monounsaturated progressively decrease as percentage levels, while among long-chain polyunsaturated fatty acids, percentages of arachidonic acid and docosahexaenoic acid decrease from colostrum up to the third month. Hindmilk total lipids (mg/dl) rise more than twofold up to 3 months, and then remain stable. The amounts (mg/dl) of linoleic acid and alpha-linolenic acid progressively increase, following the trend of total fat, while arachidonic and docosahexaenoic concentrations (mg/dl) remain stable throughout the whole nursing period. Assessment of the intakes per kg body weight shows different trends for the individual major long-chain polyunsaturated fatty acids supplied to the infant from hindmilk during exclusive breast-feeding (3 months). This information may be useful for the evaluation of infant intakes during extended lactation.     

Reduction in mortality with availability of antiretroviral therapy for children with perinatal HIV-1 infection. Italian Register for HIV Infection in Children and the Italian National AIDS Registry

CONTEXT: Since the introduction of combined antiretroviral therapy, mortality rates in adults with human immunodeficiency virus type 1 (HIV-1) infection have decreased. However, little information is available outside the setting of controlled trials on survival of perinatally HIV-infected children treated with antiretroviral therapy. OBJECTIVE: To assess effect of availability of antiretroviral therapy on decreasing mortality in perinatally HIV-infected children. DESIGN: Population-based, multicenter longitudinal study involving data collected by the Italian Register for HIV Infection in Children. SETTING: A network of 106 pediatric clinical centers. SUBJECTS: A total of 1142 children born between November 1980 and December 1997 with perinatally acquired HIV infection with a median follow-up of 5.9 years. MAIN OUTCOME MEASURE: Time to HIV-related death calculated for birth cohort and calendar period and grouped by distribution of predominant type of antiretroviral therapy administered over time. RESULTS: Survival was longer in the 1996-1997 birth cohort (crude relative hazard [RH] of death, 0.39; 95% confidence interval [CI], 0.15-0.96) and 1996-1998 calendar period (crude RH of death, 0.65; 95% CI, 0.45-0.95) than in birth cohort and calendar period 1980-1995, but not when adjusted for maternal antiretroviral treatment during pregnancy and clinical condition at time of delivery, gestational age, and birth weight (adjusted RH of death, 0.55; 95% CI, 0.20-1.50, for birth cohort; and adjusted RH of death, 0.71, 95% CI, 0.43-1.16, for calendar period). In a multivariate model with 1980-1995 as comparison, the 1996-1997 birth cohort had an RH of 0.57 (95% CI, 0.22-1.47; P=.27) but RH for calendar period 1996-1998 was 0.63 (95% CI, 0.47-0.85; P<. 01). When the effects of birth cohort, calendar period, and type of antiretroviral therapy were evaluated simultaneously in the same model, the RH of death was not significantly different from 1.0 for the 1996-1997 birth cohort (P=.19) and calendar period 1996-1998 (P=. 83) suggesting a causal relationship between decreased risk of death and use of combination therapy. The RH of death in children receiving monotherapy or double or triple combination therapy was 0. 77 (95% CI, 0.55-1.08), 0.70 (95% CI, 0.42-1.17), and 0.29 (95% CI, 0.13-0.67), respectively, vs no antiretroviral therapy. CONCLUSION: Survival of perinatally HIV-infected children improved in 1996-1998 as a result of the introduction of combined antiretroviral therapies. JAMA. 2000;284:190-197     

Videothoracoscopic approach in the treatment of intralobar pulmonary sequestration. Report of a case

The Authors report on the use of a videothorascopic approach in the treatment of a patient with intralobar bronchopulmonary sequestration. The latter is a rare malformation which more often than not manifests itself in young patients with hemophthisis, recurrent infection and cough. The condition is difficult to diagnose and is often diagnosed intraoperatively. The treatment is surgical resection. The videothorascopic approach was used in a young patient presenting a lesion of the left inferior lobe with polycyclic contours suspected of being an intralobar bronchopulmonary sequestration, along with medical history findings of cough and hyperpyrexia. The approach permitted identification of the lesion in the context of the left inferior lobe, safe identification and section of the abnormal systemic vessel supplying the lesion and subsequent inferior lobectomy. The postoperative course was uneventful and the patient was discharged on postoperative day 5 with an excellent esthetic and functional outcome. The videothorascopic approach should be taken into consideration for the diagnosis and treatment of intralobar bronchopulmonary sequestrations.