Shwachman–Diamond syndrome (SDS) in a preterm neonate

A preterm neonate at 29‐week gestational age was born with intrauterine growth restriction, severe pancytopaenia and gross skeletal dysplasia. Antenatal screening bloods, TORCH/parvovirus tests and karyotype were unremarkable. Postnatally, he had normal microarray comparative genomic hybridization and serum B12/folate levels, and human immunodeficiency virus and cytomegalovirus polymerase chain reaction and antoimmune screening were negative. Targeted gene testing for Shwachman–Diamond syndrome (SDS) revealed the pathognomic mutation (c.183_184delTAinsCT). His postnatal clinical course was complicated by: (i) Ventilator dependency because of a combination of a pathologically compliant chest wall and preterm‐associated chronic lung disease. (ii) Progressive bone marrow failure, resulting in transfusion dependence and profound neutropenia associated with recurrent sepsis. (iii) Gastrointestinal failure and TPN dependency. (iv) Poor postnatal growth with weight/length/head circumference all <3rd centile. (v) Prognostication was complicated by the lack of published literature on the presentation of SDS in a preterm infant. However, because of inexorable progression of multiorgan failure, intensive care was withdrawn on day 54 of life. SDS is a rare autosomal recessive disorder characterised by haematological abnormalities, skeletal dysplasia and exocrine pancreatic dysfunction. Neonatal presentation is thought to be extremely rare. However, with the availability of genetic testing, it has now become clear that because of overlap in clinical presentation, term‐born infants with skeletal dysplasia and severe respiratory distress may initially be misdiagnosed as asphyxiating thoracic dystrophy. This case report highlights the complexities of preterm birth complicating clinical manifestations of SDS.     

Analysis of the premalignant stages of Barrett's oesophagus through to adenocarcinoma by comparative genomic hybridization

OBJECTIVES: Barrett's oesophagus is a pre-neoplastic lesion, which develops as a complication of chronic gastro-oesophageal reflux disease and predisposes the patient to oesophageal adenocarcinoma. Our aim was to characterize karyotypic changes that may occur during the progression of Barrett's metaplasia through low-grade dysplasia and high-grade dysplasia to adenocarcinoma. METHODS: The technique of comparative genomic hybridization was used to characterize genome-wide changes in biopsies from patients with low-grade dysplasia, low-grade dysplasia plus high-grade dysplasia, high-grade dysplasia or adenocarcinoma. Both fresh and archival material was examined. RESULTS: Comparative genomic hybridization revealed a large amount of widespread chromosome instability at the high-grade dysplasia stage. No significant chromosome changes were detectable by comparative genomic hybridization in patients with low-grade dysplasia. Karyotypic changes in the adenocarcinoma patients were more specific than those found in the high-grade dysplasia patients. Chromosome 4 was amplified most often in high-grade dysplasia and chromosome 8q was amplified most frequently in the adenocarcinomas. CONCLUSIONS: These data demonstrate that high-grade dysplasia is the stage exhibiting widespread chromosome instability, which is detectable by comparative genomic hybridization. This instability is undetectable in low-grade dysplasia. The chromosome variation seen at high-grade dysplasia may be the source of more specific karyotypes that progress to adenocarcinoma. Importantly, we have identified chromosome 4 amplification as being heavily involved in the initiation of Barrett's progression. Specific chromosome changes (4 and 8q) may represent important regions on which to focus attention in future studies, with a view to identifying diagnostic markers.     

Embryo fossilization is a biological process mediated by microbial biofilms

Fossilized embryos with extraordinary cellular preservation appear in the Late Neoproterozoic and Cambrian, coincident with the appearance of animal body fossils. It has been hypothesized that microbial processes are responsible for preservation and mineralization of organic tissues. However, the actions of microbes in preservation of embryos have not been demonstrated experimentally. Here, we show that bacterial biofilms assemble rapidly in dead marine embryos and form remarkable pseudomorphs in which the bacterial biofilm replaces and exquisitely models details of cellular organization and structure. The experimental model was the decay of cleavage stage embryos similar in size and morphology to fossil embryos. The data show that embryo preservation takes place in 3 distinct steps: (i) blockage of autolysis by reducing or anaerobic conditions, (ii) rapid formation of microbial biofilms that consume the embryo but form a replica that retains cell organization and morphology, and (iii) bacterially catalyzed mineralization. Major bacterial taxa in embryo decay biofilms were identified by using 16S rDNA sequencing. Decay processes were similar in different taphonomic conditions, but the composition of bacterial populations depended on specific conditions. Experimental taphonomy generates preservation states similar to those in fossil embryos. The data show how fossilization of soft tissues in sediments can be mediated by bacterial replacement and mineralization, providing a foundation for experimentally creating biofilms from defined microbial species to model fossilization as a biological process.     

The effect of pressure bandaging on complications and comfort in patients undergoing coronary angiography: A multicenter randomized trial

OBJECTIVES: To determine the effectiveness of pressure bandaging in reducing bleeding and bruising in patients undergoing coronary angiography and to investigate the contribution that pressure bandages make to patient discomfort after angiography.DESIGN: A prospective multicenter, randomized study.SETTING: Three university hospitals in Melbourne, Australia.PATIENTS: One thousand seventy-five patients undergoing coronary angiography were randomized to receive a pressure bandage (N = 556) or no bandage (N = 519) after manual compression of the right femoral artery puncture site.RESULTS: Patients without pressure bandages had a higher incidence of bleeding (P < 0.05) and bled earlier (mean 2.4 hours; SD 3.6 hours) after catheter removal (P < 0.001) than patients with bandages (mean 5.3 hours; SD 3.8 hours). The incidence of bleeding in patients without pressure bandages was 6.7%. The incidence and extent of bruising was the same for both groups. Patients with pressure bandages experienced a higher incidence of back (P < 0.05), groin (P < 0.001), and leg pain (P < 0.001), nausea (P < 0.05), and urinary difficulty (P < 0.01).CONCLUSIONS: In view of the associated increase in patient discomfort and the delay in time of onset of bleeding, pressure bandages should not be used routinely in the management of patients after coronary angiography, especially in the context of early discharge from the hospital.     

Radioactive choline metabolism in guinea pig gallbladder

Acetylcholine may be released from gallbladder intrinsic nerves in response to cholecystokinin stimulation. This study characterized metabolites of [¹⁴C]choline produced in the gallbladder and released during incubation, with or without cholecystokinin-octapeptide. Radiolabeled [¹⁴C]choline was applied to the mucosal or muscle surface of intact guinea pig gallbladders in an organ bath. After radiolabeling, gallbladders were incubated with or without the contractile agonist cholecystokinin-octapeptide. Metabolites of [¹⁴C]choline were identified in gallbladder tissue and incubation buffers using HPLC and thin-layer chromatography. The major metabolites of [¹⁴C]choline were betaine and phosphocholine. [¹⁴C]Phosphocholine was incorporated slowly into [¹⁴C]phosphatidylcholine. [¹⁴C]Choline was released into buffers during incubation. [¹⁴C]Acetylcholine constituted less than 1% of radiolabel in the gallbladder. There was no identifiable [¹⁴C]acetylcholine released in buffers. Cholecystokinin-octapeptide did not affect choline metabolism. These studies showed that choline in the gallbladder is metabolized along pathways similar to those in the liver. Gallbladders released mostly choline, rather than acetylcholine, even during hormonally induced contraction.This project was supported by the Research and Development Office of the Department of Veterans Affairs.     

The epitopes for some antiphospholipid antibodies are adducts of oxidized phospholipid and β2 glycoprotein 1 (and other proteins)

Circulating autoantibodies to phospholipids (aPLs), such as cardiolipin (CL), are found in patients with antiphospholipid antibody syndrome (APS). We recently demonstrated that many aPLs bound to CL only after it had been oxidized (OxCL), but not to a reduced CL analogue that could not undergo oxidation. We now show that the neoepitopes recognized by some aPLs consist of adducts formed between breakdown products of oxidized phospholipid and associated proteins, such as β₂ glycoprotein 1 (β₂GP1). Addition of human β₂GP1, polylysine, native low-density lipoprotein, or apolipoprotein AI to OxCL-coated wells increased the anticardiolipin antibody (aCL) binding from APS sera that first had been diluted so that no aCL binding to OxCL could be detected. No increase in aCL binding was observed when these proteins were added to wells coated with reduced CL. The ability of β₂GP1, polylysine, or low-density lipoprotein to be a “cofactor” for aCL binding to OxCL was greatly reduced when the proteins were methylated. Incubation of β₂GP1 with oxidized 1-palmitoyl-2-linoleyl-[1-¹⁴C]-phosphatidylcholine (PC), but not with dipalmitoyl-[1-¹⁴C]-PC, led to formation of covalent adducts with β₂GP1 recognized by APS sera. These data suggest that the reactive groups of OxCL, such as aldehydes generated during the decomposition of oxidized polyunsaturated fatty acids, form covalent adducts with β₂GP1 (and other proteins) and that these are epitopes for aCLs. Knowledge that the epitopes recognized by many aPLs are adducts of oxidized phospholipid and associated proteins, including β₂GP1, may give new insights into the pathogenic events underlying the clinical manifestations of APS.     

Foodborne botulism in a six-month-old infant caused by home-canned baby food

Previously reported cases of botulism in infants have been diagnosed as infant botulism; that is, botulism caused by intestinal colonization by Clostridium botulinum with intraluminal production and absorption of toxin. Foodborne botulism is caused by ingestion of preformed toxin. We describe an unusual case of foodborne botulism in a 6-month-old infant caused by the ingestion of improperly prepared home-canned baby food. This represents the youngest age of onset for foodborne botulism in the United States of which we are aware and illustrates the need to rule out foodborne botulism, which represents a public health emergency, regardless of the patient's age. The diagnosis could have been readily missed or delayed in this case because the weakness was rapidly progressive rather than insidious, as is typical of infant botulism.     

Fc receptor gamma-chain activation via hOSCAR induces survival and maturation of dendritic cells and modulates Toll-like receptor responses

We previously reported the characterization of human osteoclast-associated receptor (hOSCAR), a novel Fc receptor gamma-chain (FcRgamma)-associated receptor expressed by myeloid cells. Here we show that ligation of hOSCAR by specific antibodies promotes dendritic cell (DC) survival by an extracellular signal-regulated kinase (ERK)- and phosphatidylinositol 3-kinase (PI3K)-dependent pathway, linked to expression of the Bcl-2 and Bcl-x(L) antiapoptotic molecules. Crosslinking of hOSCAR leads to maturation of DCs, as demonstrated by up-regulation of maturation markers, decrease in dextran uptake capacity, and secretion of immunesystem effectors such as interleukin-8 (IL-8)/CXC chemokine ligand 8 (CXCL8), IL-12 p40, monocyte chemoattractant protein-1 (MCP-1)/chemokine receptor ligand 2 (CCL2) and macrophage-derived chemokine (MDC)/CCL22. Stimulation of hOSCAR acts in conjunction with the Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS), R-848, and polyinosinic-polycytidylic acid (poly(I:C)), to increase the expression of maturation markers, and to modulate cytokine release. A PI3K-dependent up-regulation of IL-10 release is observed with all the TLR ligands used, whereas regulation of IL-12 production is variable depending on the TLR stimulated. hOSCAR engagement on DCs did not significantly increase the proliferation of naive T cells; however, when co-incubated with TLR ligands, an enhanced proliferation was observed. The percentage of interferon (IFN)-gamma-producing T cells is decreased when hOSCAR engagement is combined with LPS stimulation. Altogether, these data suggest that hOSCAR may modulate the responses of both innate resistance and adaptive immunity.