Loss of cutaneous microbial diversity during first 3 weeks of life in very low birthweight infants

Neonatal sepsis (NS) is a frequent problem in neonatal intensive care, especially in preterm and very low birthweight (VLBW) infants. The objective of the study was to characterize the cutaneous bacterial microbiome in VLBW infants treated in the neonatal intensive care unit (NICU). Non‐invasive skin microbiome specimens were taken repeatedly from 12 VLBW infants during treatment in NICU starting on the first day of life. All infants received benzylpenicillin and netilmicin during the first 1‐5 postnatal days. Samples were also collected from incubators. High cutaneous microbial diversity was present at birth in 11 of 12 of the infants, but the diversity decreased substantially after the first weeks of life in all infants regardless of their infection status. After the loss of diversity, one Staphylococcus operational taxonomic unit dominated the skin microbiome. Recovery of microbial diversity was seen in six of 12 neonates. The microbiome of incubators showed typical environmental bacterial genera. Maternal antibiotic treatment, the aetiology of the preterm birth or being born by C‐section did not appear to affect the diversity of skin microbiota at birth, and no correlation was found between cutaneous microbiome and NS.     

Extensive allelic sequence variation in the J region of the human immunoglobulin heavy chain gene locus

During the initial stages of B lymphocyte differentiation heavy chain variable (VH), diversity (DH) and joining (JH) gene segments recombine to form a functional heavy chain variable region (VDJ) gene. Evidence for genetic polymorphism of the human JH gene segments has been obtained from mature rearranged VDJ sequences. We conducted an analysis of the published rearranged JH gene sequences and found that the JH alleles present in the two published germ-line JH region sequences were rare (approx. 2%) in the rearranged sequences. As an attempt to explain this discrepancy a 2.5-kb strech of DNA containing all the six heavy chain JH region genes and the most 3' DH gene segment, DHQ52, was amplified by the polymerase chain reaction from 39 individuals and analyzed for restriction fragment length polymorphism. Five new JH region haplotypes were found and sequenced. These new haplotypes contained the coding segment alleles that were frequent in antibody genes. Surprisingly, a high number of interallelic differencies in the non-coding sequence was found between the new and the two previously published haplotypes implying that the haplotypes had been separated early in evolution. In this respect the JH locus resembles HLA loci.     

Transient transfection of the enteric parasite Entamoeba histolytica and expression of firefly luciferase.

Development of DNA-mediated transfection in Entamoeba histolytica will facilitate basic research toward the control of this protozoan parasite. A transient transfection system was established by using the firefly luciferase gene ligated to the 5' and 3' flanking regions of the amebic hgl1 gene. The optimal construct tested encoded an hgl1-luciferase fusion protein and contained 1 kb of 5' flanking sequence with 16 bases of coding sequence from the hgl1 gene ligated in-frame to the luciferase start codon and 2.3 kb of 3' flanking sequence from hgl1 ligated 3' to the luciferase stop codon. Optimal electroporation conditions in strain HM-1:IMSS trophozoites when using this construct were 500 microF and 500 V/cm, which resulted in luciferase activity up to 5000-fold above background 9-12 hr after electroporation. Constructs that contained the luciferase gene without amebic flanking sequences or that contained a simian virus 40 promoter, enhancer, and polyadenylylation signal produced only background levels of luciferase activity. The ability to introduce and express genes in amebae will now permit a genetic analysis of the virulence of this organism, which remains a serious threat to world health.     

A role of peripheral myelin protein 2 in lipid homeostasis of myelinating schwann cells

Peripheral myelin protein 2 (Pmp2, P2 or Fabp8), a member of the fatty acid binding protein family, was originally described together with myelin basic protein (Mbp or P1) and myelin protein zero (Mpz or P0) as one of the most abundant myelin proteins in the peripheral nervous system (PNS). Although Pmp2 is predominantly expressed in myelinated Schwann cells, its role in glia is currently unknown. To study its function in PNS biology, we have generated a complete Pmp2 knockout mouse (Pmp2^‐/‐). Comprehensive characterization of Pmp2^‐/‐ mice revealed a temporary reduction in their motor nerve conduction velocity (MNCV). While this change was not accompanied by any defects in general myelin structure, we detected transitory alterations in the myelin lipid profile of Pmp2^‐/‐ mice. It was previously proposed that Pmp2 and Mbp have comparable functions in the PNS suggesting that the presence of Mbp can partially mask the Pmp2^‐/‐ phenotype. Indeed, we found that Mbp lacking Shi^‐/‐ mice, similar to Pmp2^‐/‐ animals, have preserved myelin structure and reduced MNCV, but this phenotype was not aggravated in Pmp2^‐/‐/Shi^‐/‐ mutants indicating that Pmp2 and Mbp do not substitute each other's functions in the PNS. These data, together with our observation that Pmp2 binds and transports fatty acids to membranes, uncover a role for Pmp2 in lipid homeostasis of myelinating Schwann cells. GLIA 2014;62:1502–1512     

Myocardial perfusion,oxidative metabolism,and free fatty acid uptake in patients with hypertrophic cardiomyopathy attributable to the Asp 175Asn mutation in the α-tropomyosin gene: A positron emission tomography study

Background  The relationship between myocardial metabolic changes and the severity of left ventricular (LV) hypertrophy in patients with hypertrophic cardiomyopathy (HCM) is largely unknown. We characterized metabolic abnormalities in patients with a genetically identical cause for HCM but with variable LV hypertrophy. Methods and Results  Eight patients with HCM attributable to the Asp175Asn mutation in the α-tropomyosin gene underwent myocardial perfusion, oxidative, and free fatty acid (FFA) metabolism measurements via positron emission tomography and oxygen 15-labeled water, carbon 11 acetate, and fluorine 14(R,S)-[18F] Fluoro-6-thia-heptadecanoic acid (18 FTHA). LV mass, work, and efficiency were assessed by echocardiography. Thirty-six healthy volunteers served as control subjects. Compared with control subjects, HCM patients had increased myocardial oxidative metabolism and FFA uptake (P<.05). However, in patients, LV mass was inversely related to global myocardial perfusion, oxidative metabolism, and FFA uptake (all P<.03), and regional wall thickness was inversely related to regional perfusion (P<.01), oxidative metabolism (P<.001), and FFA uptake (P<.01). Therefore patients with mild (LV mass less than median of 177 g) but not advanced LV hypertrophy were characterized by increased perfusion, oxidative metablism, and LV efficiency as compared with control subjects (P<.05). Conclusions  In HCM attributable to the Asp 175Asn mutation in the α-tropomyosin gene, myocardial oxidative metabolism and FFA metabolism are increased and inversely related to LV hypertrophy at both the whole heart and regional level. Increased metabolism and efficiency characterize patients with mild myocardial hypertrophy. These hypermetabolic alterations regress with advanced hypertrophy. Dis Tuunanen and Kuusisto contributed equally to this work This study was financially supported by an EVO grant (Kuopio University Hospital), as well as the Turunen Foundation, Instrumentarium Foundation, and Finish Cultural Foundation.     

Intravenous isosorbide dinitrate in acute left ventricular failure--a dose--response study

The haemodynamic effects of intravenous isosorbide dinitrate(Cedocard) in patients with severe acute left ventricular failurehave been assessed using incremental infusion rates from 50to 800µmin^–1. For most patients most of the fallin pulmonary arterial diastolic pressure occurred by 200µgmin^–1, with little further fall at higher doses. At 200µgmin^–1pulmonary arterial diastolic pressure fell from 29 to 23 mgHg(P<0.001), there was no significant change in cardiac index(1.9 to 2.0Lmin^–1m^–2) or heart rate (108 to 108beats min^–1). Despite high doses, no side effects wereobserved. Intravenous isosorbide dinitrate is effective and safe in themanagement of acute severe left ventricular failure. In mostpatients an infusion rate of about 200µg min^–1 producesoptimal haemodynamic effects.     

Intraspinal administration of human spinal cord‐derived neural progenitor cells in the G93A–SOD1 mouse model of ALS delays symptom progression,prolongs survival and increases expression of endogenous neurotrophic factors

Neural stem or progenitor cells are considered to be a novel therapeutic strategy for amyotrophic lateral sclerosis (ALS), based on their potential to generate a protective environment rather than to replace degenerating motor neurons. Following local injection to the spinal cord, neural progenitor cells may generate glial cells and release neurotrophic factors. In the present study, human spinal cord‐derived neural progenitor cells (hscNPCs) were injected into the lumbar spinal cord of G93A–SOD1 ALS transgenic mice. We evaluated the potential effect of hscNPC treatment by survival analysis and behavioural/phenotypic assessments. Immunohistological and real‐time PCR experiments were performed at a defined time point to study the underlying mechanisms. Symptom progression in hscNPC‐injected mice was significantly delayed at the late stage of disease. On average, survival was only prolonged for 5 days. Animals treated with hscNPCs performed significantly better in motor function tests between weeks 18 and 19. Increased production of GDNF and IGF‐1 mRNA was detectable in spinal cord tissue of hscNPC‐treated mice. In summary, treatment with hscNPCs led to increased endogenous production of several growth factors and increased the preservation of innervated motor neurons but had only a small effect on overall survival. Copyright © 2015 John Wiley & Sons, Ltd.     

Association between TNF-�� and Entamoeba histolytica Diarrhea

An association between tumor necrosis factor α (TNF-α) and Entamoeba histolytica diarrhea was assessed in a cohort of 138 non-related Bangladeshi children who have been prospectively followed since 2001. Peripheral blood mononuclear cells (PBMCs) obtained at study entry were purified, cultured, and stimulated with soluble amebic antigen before cytokine measurement from supernatant. Higher levels of TNF-α were associated with increased risk of first (P = 0.01) and recurrent E. histolytica-related diarrheal episodes (P = 0.005). Children who developed E. histolytica diarrhea had significantly higher TNF-α protein levels than those who experienced asymptomatic E. histolytica infection (P value = 0.027) or no infection (P value = 0.017). Microarray studies performed using RNA isolated from acute and convalescent whole blood and colon biopsy samples revealed higher but non-significant TNF-α messenger RNA (mRNA) levels in subjects with acute E. histolytica diarrhea compared with convalescence. We conclude that there is an association between higher TNF-α production and E. histolytica diarrhea.