A mutation in the peroxisome proliferator-activated receptor γ-binding site in the gene for the cytosolic form of phosphoenolpyruvate carboxykinase reduces adipose tissue size and fat content in mice

Regulation of the turnover of triglycerides in adipose tissue requires the continuous provision of 3-glycerophosphate, which may be supplied by the metabolism of glucose or by glyceroneogenesis, the de novo synthesis of 3-glycerophosphate from sources other than hexoses or glycerol. The importance of glyceroneogenesis in adipose tissue was assessed in mice by specifically eliminating the expression of the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK-C), an enzyme that plays a pivotal role in the pathway. To accomplish this, we mutated the binding site for the peroxisome proliferator-activated receptor gamma (PPAR gamma) called the peroxisome proliferator-activated receptor element (PPARE), in the 5' flanking region of the PEPCK-C gene in the mouse by homologous recombination. The mutation abolished expression of the gene in white adipose tissue and considerably reduced its expression in brown adipose tissue, whereas the level of PEPCK-C mRNA in liver and kidney remained normal. Epididymal white adipose tissue from these mice had a reduced triglyceride deposition, with 25% of the animals displaying lipodystrophy. There was also a greatly reduced level of lipid accumulation in brown adipose tissue. A strong correlation between the hepatic content of triglycerides and the size of the epididymal fat pad in PPARE(-/-) mice suggests that hepatic triglyceride synthesis predominantly utilizes free fatty acids derived from the adipose tissue. Unlike other models, PPARE(-/-) mice with lipodystrophy did not exhibit the lipodystrophy-associated features of diabetes and displayed only moderate hyperglycemia. These studies establish the importance of the PPARE site for PEPCK-C gene expression in adipose tissue and the role of PEPCK-C in the regulation of glyceroneogenesis, a pathway critical for maintaining the deposition of triglycerides in adipose tissue.     

Reliability and validity of the center for epidemiologic studies depression scale in patients with systemic sclerosis

OBJECTIVE: Reported rates of depressive symptoms in patients with systemic sclerosis (SSc) are high. No depression assessment tools, however, have been validated for patients with SSc. Our objective was to assess the internal consistency reliability, convergent validity, and structural/construct validity of the Center for Epidemiologic Studies Depression Scale (CES-D) in patients with SSc. METHODS: We conducted a cross-sectional, multicenter study of 470 SSc patients. Internal consistency reliability was assessed with Cronbach's alpha and structural/construct validity with confirmatory factor analysis. RESULTS: Internal consistency reliability was good for the overall CES-D scale (alpha = 0.88) and for its 4 factors (alpha = 0.67-0.88). Correlations of the CES-D total score were -0.73 with mental health, -0.36 with physical health, 0.41 with disability, and 0.44 with pain. The 4-factor model originally found in the general population and validated for patients with rheumatoid arthritis (depressed affect, somatic/vegetative, [lack of] positive affect, and interpersonal factors) fit the data well, as did a second-order version of the same model with an overarching depression factor that loaded onto each of the 4 first-order factors. The 4-factor model fit the SSc data better than alternative models. CONCLUSION: Internal consistency reliability and convergent validity were good, the 4-factor structure reported in the general population was replicated, and a second-order model with an overarching depression factor fit well. These findings indicate that the CES-D is a valid and reliable measure of depressive symptoms for patients with SSc.     

Large-scale, polymerase chain reaction-based surveillance of Schistosoma haematobium DNA in snails from transmission sites in coastal Kenya: a new tool for studying the dynamics of snail infection

Levels of prepatent Schistosoma haematobium infection were monitored in intermediate host snails (Bulinus nasutus) collected from transmission sites in coastal Kenya, using a polymerase chain reaction (PCR) assay amplifying the Dra I repeated sequence of S. haematobium. The timing and number of prepatent and patent infections were determined for each site and, where the time of first appearance was clear, the minimal prepatent period was estimated to be five weeks. High, persistent, prepatency rates (range = 28-54%), indicated a significant degree of repeated area contamination with parasite ova. In contrast, rates of cercarial shedding proved locally variable, and were either low (range = 0.14-3.4%) or altogether absent, indicating that only a small proportion of infected snails reach the stage of cercarial shedding. Given the apparently strong focal effects of environmental conditions, implications of these new data are discussed regarding the estimation of local force of transmission and the design of control activities.     

Oxidative stress causes telomere damage in Fanconi anaemia cells - a possible predisposition for malignant transformation

Fanconi anaemia (FA) is an autosomal recessive and X-linked disease characterized by severe genetic instability and increased incidence of cancer. One explanation for this instability may be the cellular hypersensitivity to oxidative stress leading to chromosomal breaks. This study explored the possible oxidative damage to telomeres of FA lymphocyte cell line, HSC536/N, and its possible effect on telomere function. We postulated that combination of oxidative damage with overexpression of telomerase may provide a possible model for malignant transformation in FA. The cells were grown in the presence of telomerase inhibitor and exposed for 1 month to H₂O₂ combined with various antioxidants. This exposure caused shortening of telomere length and damage to the telomere single stranded overhang, which was prevented by several oxidants. This shortening was associated with development of severe telomere dysfunction. Control cells did not exhibit this sensitivity to H₂O₂. Telomere dysfunction did not evoke damage response in FA cells, in contrast to normal P53 upregulation in control cells. Reconstitution of telomerase activity protected FA telomeres from further oxidative damage. These results suggest a scenario in which oxidative stress causes telomere shortening and ensuing telomere dysfunction may form the basis for malignant transformation in FA cells. Upregulation of telomerase activity in sporadic FA cells may perpetuate that process, thus explaining the malignant character of FA cells in vivo .     

The accuracy of Gram stain of respiratory specimens in excluding Staphylococcus aureus in ventilator-associated pneumonia

Objective

To evaluate the Gram stain of deep tracheal aspirate as a tool to direct empiric antibiotic therapy, and more specifically as a tool to exclude the need for empiric antibiotic coverage against Staphylococcus aureus in ventilator-associated pneumonia (VAP).

Design

A prospective, single-center, observational, cohort study.

Setting

All wards at a community hospital.

Patients

Adult patients requiring mechanical ventilation, identified as having VAP in a 54-month prospective surveillance database.

Interventions

Sampling of lower airway secretions by deep endotracheal aspiration was taken from each patient who developed VAP. Samples were sent immediately for Gram stain and qualitative bacterial cultures. Demographic and relevant clinical data were collected; Gram stain, culture, and antibiotic susceptibility results were documented; and outcome was followed prospectively.

Measurements and Main Results

The analysis included 114 consecutive patients with 115 episodes of VAP from June 2007 to January 2012. Sensitivity of Gram stain compared with culture was 90.47% for gram-positive cocci, 69.6% for gram-negative rods, and 50% for sterile cultures. Specificity was 82.5%, 77.8%, and 79%, respectively. Negative predictive value was high for gram-positive cocci (97%) and sterile cultures (96%) but low for gram-negative rods (20%). Acinetobacter baumanii (45%) and Pseudomonas aeruginosa (38 %) were the prevailing isolates. S aureus was found in 18.3% of the patients. Most isolates were multiresistant.

Conclusions

Absence of gram-positive bacteria on Gram stain had a high negative predictive value. These data can be used to narrow the initial empiric antibiotic regimen and to avoid unnecessary exposure of patients to vancomycin and other antistaphyloccocal agents.     

Compound heterozygosity of HLA‐DRB3*01:01 and HLA‐DRB4*01:01 as a potential predictor of fetal neonatal alloimmune thrombocytopenia

BACKGROUND: Fetal neonatal alloimmune thrombocytopenia (FNAIT) is a life‐threatening bleeding disorder in the fetus or neonate caused by maternal alloantibodies directed against fetal platelet (PLT) antigens inherited from the father. The immune‐dominant antigen leading to severe FNAIT is the human PLT antigen (HPA)‐1, whose polymorphism constitutes an epitope for human leukocyte antigens (HLAs), usually DRB3*0101 leading to an immune response. STUDY DESIGN AND METHODS: In this study our aims were to find whether other allele variants of the β subunit of the HLA‐DR family specifically focused on the HLA residues that bind Position 33 of the HPA‐1 integrin contribute to FNAIT development and affect response to treatment and whether coexistence of both anti‐HPA‐1a and anti‐HLA Class I specific against the father's antigens leads to a more severe thrombocytopenia in the newborn. We examine the genotype of 23 mothers to newborns with FNAIT compared to a control group. RESULTS: Our results suggested that, when HPA‐1 incompatibility with the husband is found, the presence of two HLA alleles (DRB3*01:01 and DRB4*01:01) in the mother increases the risk and severity of FNAIT and reduces the success of a preventive immunoglobulin G treatment. We provide a structural model for the molecular basis of the rational effects of the different HLA alleles. In addition, we found that the presence of both anti‐HPA‐1 and anti‐HLAs did not aggravate FNAIT in comparison to mothers harboring only anti‐HPA‐1. CONCLUSION: Overall, we suggest that a specific genotyping of the mother in relation to HLA‐DRB as well as HPA‐1 can serve as an antenatal diagnostic tool, particularly in siblings of women who gave birth to neonates with FNAIT.     

Focal liver necrosis appears early after partial hepatectomy and is dependent on T cells and antigen delivery from the gut

Introduction: Progressive liver failure may develop following removal of a large part of the liver or transplantation of a small for size liver graft. The pathophysiology of this clinical syndrome is only partially understood. Methods: We assessed liver damage and hepatocyte 5‐bromo‐2′‐deoxyuridine (BrdU) incorporation following partial hepatectomy (PH) in C57BL/6, BALB/C and immune‐deficient mice. Hepatic lymphocyte subpopulations were characterized. Lipopolysaccharide (LPS) treatment and bowel decontamination determined the role of gut antigens. Results: Discrete, round necrotic lesions were observed as early as 2 h following 70%, but not 30% PH. In immune competent mice the extent of hepatocyte necrosis inversely correlated with BrdU incorporation. T, natural killer and natural killer T cells were recruited to the liver early after PH; however, only T‐cell depletion abrogated hepatic necrosis. Hepatic injury was significantly reduced in non‐obese diabetic/severe combined immunodeficient mice undergoing PH, while BrdU incorporation was not affected. Liver injury was augmented by LPS injection and reduced by gut decontamination. Conclusions: A distinct pattern of early focal hepatic necrosis is observed following extensive PH in mice. T cells infiltrating the liver immediately after PH and gut‐derived antigens are indispensable for the observed liver necrosis and may thus provide therapeutic targets to ameliorate liver damage following PH.     

Spontaneous activity in premature infants affects bone strength.

OBJECTIVE: Determination of bone strength of lower extremities in very low birth weight (VLBW) premature infants with central nervous system pathology resulting in reduced unilateral spontaneous leg movements. STUDY DESIGN: Quantitative ultrasound (QUS) measurements of speed of sound (SOS) of the tibiae of both legs in three VLBW premature infants with brain insult and unilateral reduced spontaneous activity. Results were compared to QUS measurements of both legs in healthy premature infants. Measurements were performed by the same investigator who was blinded to the clinical course of the participants. RESULTS: Reduced spontaneous activity of one leg due to brain pathology resulted in decreased tibial SOS in the affected side. There was no difference in bone SOS between the legs of the healthy controls. CONCLUSION: Spontaneous movements (mainly antigravity flexion and extension) are important for bone structure and mineralization in VLBW premature infants. QUS may become an important diagnostic modality for the evaluation, treatment, and follow-up of bone strength and osteopenia in this unique population.     

Improved survival and marrow engraftment of mice transplanted with bone marrow of GM-CSF-treated donors

Abstract: Recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) administered to bone marrow (BM) transplant recipients is associated with earlier recovery. We have investigated the possibility of stimulating normal donor mice in vivo with GM-CSF. Donor balb/c mice were injected i.p. with GM-CSF (5000 u) or saline. Seventy-two hours later 5 × 10⁵ BM cells from either GM-CSF-treated or control donors were infused into lethally irradiated (850 R) recipients. In the recipients of BM from GM-CSF-treated donors, significantly higher CFU-S and significantly higher survival rate (57% [n = 65]; vs. 30% [n = 63]; p<0.05) were noted. Donor mice of the GM-CSF group did not differ in bone-marrow cellularity and composition from their controls. However, recipients of BM from GM-CSF-treated mice had higher blood counts of haemoglobin, leukocytes and platelets compared to controls. These data demonstrate that pretreatment of BM donors with GM-CSF may be of benefit in improving survival and marrow engraftment in mice.     

Heat labile enterotoxin of E. coli: a potential adjuvant for transcutaneous cancer immunotherapy

Escherichia coli heat labile enterotoxin (LT) has been shown to penetrate intact skin and to activate adaptive immunity. A nontoxic mutant, nLT, and its B subunit (LTB), have been evaluated separately for their potential use as a tool for transcutaneous delivery of antigens for cancer immunotherapy. We have shown that FITC-labeled nLT is taken up by human dendritic cells (hDC) in vitro and in mouse skin, and induces maturation and activation of hDC in vitro. hDC matured with nLT enhanced nonspecific melanoma antigen uptake and presentation to autologous CD8+ T cells. In mouse in vivo studies, nLT or LTB were applied on the skin either mixed with recombinant gp100 or genetically fused with a multiepitope polypeptide (MEP). Fused LTB-MEP induced antibody production that was dependent on LTB cell binding. We conclude that LT derivatives may be useful for the transcutaneous delivery of tumor antigens for cancer immunotherapy.