Cell cycle kinetic changes induced by interleukin-3 and interleukin-6 during ex vivo expansion of mobilized peripheral blood CD34 cells

The long-term repopulating capacity of mobilized peripheral blood (MPB) CD34+ cells can be abrogated during ex vivo expansion due to cell-cycle related changes. In this study, we traced cell cycle kinetic and quiescent status of CD34+ cells during ex vivo expansion with exogenous cytokines. The addition of interleukin-3 (IL-3) and interleukin-6 (IL-6) to early acting cytokines resulted in a significantly lower percentage of cells remaining undivided or in quiescent G0 phase when compared to the use of early acting cytokines alone. We conclude that ex vivo expansion of MPB CD34+ cells with a cocktail of five cytokines yields a highly cycling offspring, which could impair long-term repopulating capacity.     

Cultural Values and Caregiver Preference for Mexican-American and Non-Latino White Elders

This study examined caregiver preferences in the event of hip fracture between Mexican-American and non-Latino White elders. The differential effects of ethnicity and a cultural factor were also examined to elucidate the role of culture on caregiver preference.Data came from a cross-sectional survey of 89 Mexican-American and 30 non-Latino White elders. Hierarchical binary logistic regression was used to examine the differential impact of ethnicity and a cultural factor on caregiver preference. Fewer Mexican-American elders than non-Latino White elders preferred to rely on a formal/professional helper, and a greater proportion of Mexican-Americans than non-Latino Whites would turn to informal caregivers when faced with care needs following a hip fracture. The cultural factor significantly mediated the ethnic effect on caregiver preference. The need for culturally-relevant services based on caregiver preference for long-term care is discussed in addressing health disparities for ethnically diverse elders.     

An outbreak of Burkholderia cepacia associated with contamination of albuterol and nasal spray

BACKGROUND: Species within the Burkholderia cepacia complex (Bcc) can contaminate medications and disinfectants and cause severe pneumonia in critically ill patients or persons with cystic fibrosis. In March 2004, we investigated a hospital outbreak of Bcc possibly associated with a contaminated nasal spray. METHODS: We conducted a matched case-control study, environmental sampling, and observations of infection control practices. Case patients had infection or colonization with Bcc, and control patients had sputum culture not yielding Bcc. Isolates from patients and environmental samples were compared by pulsed-field gel electrophoresis (PFGE). RESULTS: Bcc was recovered from sputum in 18 patients. Compared with matched control patients (n = 18), case patients were more likely to be receiving mechanical ventilation (p = 0.01), to have been hospitalized > 6 days (p = 0.01), and to have received antimicrobial treatment within 7 days before sputum collection (p = 0.03). Bcc was cultured from opened, but not unopened, multidose albuterol bottles, a nebulizer attached to a ventilator, and opened and unopened nasal spray bottles from contaminated lots. PFGE showed that isolates from albuterol samples and from patients were indistinguishable but unrelated to the nasal spray strain. Observations revealed improper aseptic techniques during respiratory therapy procedures and inadequate nebulizer cleaning. CONCLUSIONS: Despite a temporal association with use of a contaminated nasal spray, this outbreak was caused by extrinsic contamination of multidose albuterol used for nebulization treatments and lack of adherence to infection control precautions. Implementation and re-enforcement of infection control measures successfully terminated the outbreak.     

Myeloperoxidase Is an Early Biomarker of Inflammation and Cardiovascular Risk in Prepubertal Obese Children

OBJECTIVE

Obesity is associated with a state of chronic low-grade inflammation. Myeloperoxidase (MPO) plays an important role in the initiation and progression of acute and chronic inflammatory diseases, such as cardiovascular disease (CVD). The objectives of the current study were to evaluate plasma MPO levels in prepubertal obese children and to determine whether MPO could be an early biomarker of inflammation and CVD risk.

RESEARCH DESIGN AND METHODS

In a prospective multicenter case-control study paired by age and sex of 446 Caucasian prepubertal children ages 6–12 years, 223 normal-weight and 223 obese children were recruited. Blood pressure, waist circumference, weight, and height were measured. In addition to MPO, glucose, insulin, metabolic lipid parameters, oxidized low-density lipoproteins, adiponectin, leptin, resistin, C-reactive protein (CRP), interleukin 6, tumor necrosis factor α, matrix metalloproteinase-9 (MMP-9), and plasminogen activator inhibitor 1 were determined.

RESULTS

We found that MPO was elevated in prepubertal obese children and that this enzyme was associated with such proinflammatory and cardiovascular risk biomarkers as CRP, MMP-9, and resistin. Insulin resistance calculated by the homeostatic assessment model was the best predictor of MPO.

CONCLUSIONS

MPO is an early biomarker of inflammation associated with CVD risk in obese children at the prepubertal age.Obesity is characterized by a chronic low-grade inflammation (1). Obese children have been shown to develop many proinflammatory and proatherogenic changes associated with vascular diseases in adults, including high plasma levels of C-reactive protein (CRP) (2), interleukin 6, and tumor necrosis factor-α (TNF-α) (3). In addition, it has been demonstrated that some factors involved in vascular homeostasis, such as plasminogen activator inhibitor 1 (PAI-1) (4), and in angiogenesis, such as matrix metalloproteinase 9 (MMP-9) (5), are elevated in the plasma of obese children, whereas others, such as adiponectin, are decreased.Myeloperoxidase (MPO) is an enzyme most abundantly expressed in neutrophils and, to a lesser extent, in monocytes (6). This enzyme has long been viewed as functioning primarily as a bactericidal agent (7), generating reactive oxygen species that contribute to the destruction and killing of the engulfed pathogens (6). It has been demonstrated that MPO is involved in cellular homeostasis and plays an important role in the initiation and progression of acute and chronic inflammatory diseases, fundamentally cardiovascular diseases (CVD). Recent studies have reported elevated MPO levels in obese adults (8,9). Furthermore, some studies in children have shown that MPO is elevated in subjects with diabetes mellitus type 1 (10) and with hypercholesterolemia (11), although as far as we know, no data have been reported in obese children at the prepubertal period. The objectives of the current study were therefore to evaluate plasma MPO levels in prepubertal obese children and to determine whether MPO could be an early biomarker of inflammation and CVD risk.     

Fatigue symptoms relate to systemic inflammation in patients with type 2 diabetes

Fatigue is frequent in patients with diabetes and this symptom appears to be more prominent in type 2 rather than type 1 diabetic subjects. Chronic inflammation represents one characteristic of type 2 diabetes that may contribute to fatigue symptoms. This possibility was assessed in a sample of 20 type 2 diabetic patients relatively to a group of 20 type 1 diabetic subjects. Specific dimensions of fatigue, including general fatigue, physical fatigue, reduced activity, mental fatigue and reduced motivation, were assessed using the Multidimensional-Fatigue-Inventory (MFI). Biological assays comprised the measurement of serum inflammatory markers [high-sensitive C-reactive-protein (hsCRP), high-sensitive interleukin-6 (hsIL-6), high-sensitive tumor-necrosis-factor-α (hsTNF-α) and neopterin]. Clinical parameters including indexes of adiposity were collected. In comparison to type 1 diabetic subjects, patients with type 2 diabetes exhibited higher fatigue scores, notably in the dimensions of general fatigue, physical fatigue and reduced activity, together with greater levels of inflammatory markers that correlated with indexes of adiposity. Regression analyses controlling for diabetes duration, insulin treatment status, glycemic control and fasting status, indicated that levels of inflammatory markers, in particular hsIL-6, hsCRP and neopterin, were associated with MFI fatigue dimensions in type 2 diabetic patients. Mediation analyses revealed that adiposity did not significantly account for the relationship of inflammatory markers with fatigue scores albeit coefficient regressions decreased somewhat when this variable was controlled for in regression models. These findings indicate that systemic low-grade inflammation relates to fatigue symptoms in patients with type 2 diabetes and suggest the involvement of inflammatory processes in the pathophysiology of diabetes-related fatigue.     

Remote cerebellar hemorrhage after lumbar spinal surgery

Remote cerebellar hemorrhage (RCH) is a rare complication after supratentorial or spinal surgery. RCH is poorly known and hence probably underdiagnosed. Diminished consciousness and headache are the most common clinical features. Computed tomography and magnetic resonance reveal a characteristic pattern of linear bleeding between the cerebellar folia. The pathophysiological mechanism is disputed but is probably venous bleeding secondary to significant intraoperative or postoperative loss of cerebrospinal fluid. Multiple risk factors have been described, but postsurgical negative pressure drainage of cerebrospinal fluid is the only clearly predisposing factor. We present a case of RCH after spinal surgery with a literature review.     

Tests for genetic interactions in type 1 diabetes: linkage and stratification analyses of 4,422 affected sib-pairs

OBJECTIVE

Interactions between genetic and environmental factors lead to immune dysregulation causing type 1 diabetes and other autoimmune disorders. Recently, many common genetic variants have been associated with type 1 diabetes risk, but each has modest individual effects. Familial clustering of type 1 diabetes has not been explained fully and could arise from many factors, including undetected genetic variation and gene interactions.

RESEARCH DESIGN AND METHODS

To address this issue, the Type 1 Diabetes Genetics Consortium recruited 3,892 families, including 4,422 affected sib-pairs. After genotyping 6,090 markers, linkage analyses of these families were performed, using a novel method and taking into account factors such as genotype at known susceptibility loci.

RESULTS

Evidence for linkage was robust at the HLA and INS loci, with logarithm of odds (LOD) scores of 398.6 and 5.5, respectively. There was suggestive support for five other loci. Stratification by other risk factors (including HLA and age at diagnosis) identified one convincing region on chromosome 6q14 showing linkage in male subjects (corrected LOD = 4.49; replication P = 0.0002), a locus on chromosome 19q in HLA identical siblings (replication P = 0.006), and four other suggestive loci.

CONCLUSIONS

This is the largest linkage study reported for any disease. Our data indicate there are no major type 1 diabetes subtypes definable by linkage analyses; susceptibility is caused by actions of HLA and an apparently random selection from a large number of modest-effect loci; and apart from HLA and INS, there is no important susceptibility factor discoverable by linkage methods.Type 1 diabetes is an autoimmune disease in which the insulin-producing β-cells are destroyed. The defective immune mechanisms in type 1 diabetes have not been identified, although clearly both genes and environmental factors contribute to risk (1,2). Many studies have been performed on the genetics of type 1 diabetes, and identification of the risk genes is ongoing. The Type 1 Diabetes Genetics Consortium (T1DGC) was established in response to the need to identify type 1 diabetes risk genes (3).The T1DGC has assembled DNA, sera, cell lines, and data from 17,129 individuals in 3,892 affected–sib-pair (ASP) families, representing the largest family collection in any immune-mediated disease. Using these resources, the T1DGC performed smaller genome-wide linkage studies (4,5) and association studies, finding 21 new loci (6). In addition, the T1DGC conducted the most detailed investigation of the HLA complex in disease, characterizing over 3,000 single nucleotide polymorphisms (SNPs), and independently tested all previously reported type 1 diabetes susceptibility genes (7,8; and associated special reports).From these and other studies, over 50 loci have been identified that affect the risk of developing type 1 diabetes (6) (www.t1dbase.org). Foremost among these is the HLA complex, which is long recognized as the most important risk factor in type 1 diabetes and other immune diseases. The second locus identified was INS, but this and other non-HLA loci have relatively minor risk effects comparable to loci mapped in other common diseases, with risk estimates typically between 1.05 and 2.0 (6).Despite the T1DGC’s success, not all the estimated familial heritability for type 1 diabetes has been found. Twin studies suggest ~80% of clustering is a result of sharing of susceptibility alleles at multiple loci. This issue of “missing heritability” also arises in other complex genetic diseases (9). A number of other issues pertaining to type 1 diabetes remain unresolved. For example, can it be subdivided into disease subtypes with different genetic etiology? Can we identify major genetic interactions in susceptibility? Are there loci with multiple rare risk alleles that may have gone undetected in association studies? Does genomic instability in the form of structural variants play a role?Motivated by these issues, we report here the genotyping of the final 1,583 T1DGC ASPs and perform linkage analyses on a total of 3,892 families and 17,129 individuals. The T1DGC family collection provides 80% power to search for loci undetectable by genome-wide association SNP scanning with effects of the same magnitude as the insulin gene with allelic odds ratio of ~2 and an allele frequency of 0.3. If there is residual “missing heritability” (i.e., loci that were not found by the SNP studies), this large dataset is a valuable resource to search for it. In this report, we describe a linkage search for genetic interactions in type 1 diabetes.     

Dronedarone,an Amiodarone Analog with Improved Anti-Leishmania mexicana Efficacy

Dronedarone and amiodarone are cationic lipophilic benzofurans used to treat cardiac arrhythmias. They also have activity against the parasitic protozoan Trypanosoma cruzi, the causative agent of Chagas'' disease. They function by disrupting intracellular Ca²⁺ homeostasis of the parasite and by inhibiting membrane sterol (ergosterol) biosynthesis. Amiodarone also has activity against Leishmania mexicana, suggesting that dronedarone might likewise be active against this organism. This might be of therapeutic interest, since dronedarone is thought to have fewer side effects in humans than does amiodarone. We show here that dronedarone effectively inhibits the growth of L. mexicana promastigotes in culture and, more importantly, has excellent activity against amastigotes inside infected macrophages (the clinically relevant form) without affecting the host cell, with the 50% inhibitory concentrations against amastigotes being 3 orders of magnitude lower than those obtained previously with T. cruzi amastigotes (0.65 nM versus 0.75 μM). As with amiodarone, dronedarone affects intracellular Ca²⁺ homeostasis in the parasite, inducing an elevation of intracellular Ca²⁺ levels. This is achieved by rapidly collapsing the mitochondrial membrane potential and inducing an alkalinization of acidocalcisomes at a rate that is faster than that observed with amiodarone. We also show that dronedarone inhibits parasite oxidosqualene cyclase, a key enzyme in ergosterol biosynthesis known to be vital for survival. Overall, our results suggest the possibility of repurposing dronedarone as a treatment for cutaneous, and perhaps other, leishmaniases.