Bartonella koehlerae, a new cat-associated agent of culture-negative human endocarditis

Bartonella koehlerae is reported for the first time to be a human pathogen that causes culture-negative endocarditis. It is also shown that this species, isolated twice before from domestic cats, can be recovered as well from a stray cat population in Israel. This work follows a recent report of the same case in which the causative agent was misidentified as B. henselae, based on serology and PCR-restriction fragment length polymorphism (RFLP) analysis (A. Schattner, O. Zimhony, B. Avidor, and M. Gilad, Lancet 361:1786, 2003). B. koehlerae was identified in the valvular tissue of an endocarditis patient by DNA sequencing of the PCR products of two Bartonella genes: the genes for citrate synthase (gltA) and riboflavin synthase (ribC). The commonly used PCR-RFLP analysis of the TaqI-digested gltA PCR product did not distinguish between B. koehlerae and B. quintana or between B. elizabethae and B. clarridgeiae. PmlI digestion of the gltA amplification product failed to differentiate between B. quintana, B. clarridgeiae, and B. elizabethae. RFLP analysis of the heat shock protein (htrA) gene by TaqI digestion misidentified B. koehlerae as B. henselae. However, RFLP analysis of the ribC PCR product, digested with TaqI, was able to distinguish between the human endocarditis-associated Bartonella species tested, B. henselae, B. quintana, B. elizabethae, and B. koehlerae, as well as between the cat-associated Bartonella species, B. henselae and B. clarridgeiae. Given the expanding number of Bartonella species emerging as human pathogens, it is suggested that PCR-RFLP analysis for the diagnosis of Bartonella infections target several genes and be coupled with DNA sequencing to avoid species identification.     

GaitaBase: Web-based repository system for gait analysis

The need to share gait analysis data to improve clinical decision support has been recognised since the early 1990s. GaitaBase has been established to provide a web-accessible repository system of gait analysis data to improve the sharing of data across local and international clinical and research community. It is used by several clinical and research groups across the world providing cross-group access permissions to retrieve and analyse the data. The system is useful for bench-marking and quality assurance, clinical consultation, and collaborative research. It has the capacity to increase the population sample size and improve the quality of ‘normative’ gait data. In addition the accumulated stored data may facilitate clinicians in comparing their own gait data with others, and give a valuable insight into how effective specific interventions have been for others.     

Immunology, Autoimmunity, and Autoantibodies in Parkinson’s Disease

Recent revelations of immune alterations in Parkinson??s disease have led to the convergence that an autoimmune mechanism may play a role in the etiopathogenesis of this neurodegenerative disease. In the current study, 77 Parkinson??s disease patients and 77 matched healthy controls were analyzed for the presence of seven autoantibodies previously found to be associated with central nervous system manifestations namely: antineuronal-cells, anti-brain lysate, anti-dsDNA, anti-phosphatidylserine, anti-cardiolipin, anti-serotonin, and anti-melanocytes antibodies. Patients underwent systematic assessments of demographics, clinical, and biochemical manifestations. Three autoantibodies were found to be more prevalent among Parkinson??s disease patients (antineuronal cells10.3% vs. 1.3%, p?=?0.017; anti-brain lysate 9.1% vs. 1.3%, p?=?0.032; anti-dsDNA 10.3% vs. 2.6%, p?=?0.049). Clinical manifestations of Parkinson??s disease, particularly dyskinesia and depression, were found to be associated with the presence of these autoantibodies.     

PI3K pathway regulates survival of cancer stem cells residing in the perivascular niche following radiation in medulloblastoma in vivo

Medulloblastomas are brain tumors that arise in the cerebellum of children and contain stem cells in a perivascular niche thought to give rise to recurrence following radiation. We used several mouse models of medulloblastomas in parallel to better understand how the critical cell types in these tumors respond to therapy. In our models, the proliferating cells in the tumor bulk undergo radiation-induced, p53-dependent apoptotic cell death. Activation of Akt signaling via PTEN loss transforms these cells to a nonproliferating extensive nodularity morphology. By contrast, the nestin-expressing perivascular stem cells survive radiation, activate PI3K/Akt pathway, undergo p53-dependent cell cycle arrest, and re-enter the cell cycle at 72 h. Furthermore, the ability of these cells to induce p53 is dependent on the presence of PTEN. These cellular characteristics are similar to human medulloblastomas. Finally, inhibition of Akt signaling sensitizes cells in the perivascular region to radiation-induced apoptosis.     

Cellular localization of complement C3 and C4 transcripts in intestinal specimens from patients with Crohn's disease

It has been suggested that the increase in C3 and C4 levels in jejunal perfusates of patients with Crohn's disease (CD) results from local intestinal synthesis of complement. The present study evaluated the expression of these complement genes in inflamed tissues from patients with CD. Surgically resected specimens from patients with CD and control tissue obtained from subjects with adenocarcinoma of the colon were evaluated for C3 and C4 gene expression by the use of 35S-labelled anti-sense RNA probes. All tissue samples, diseased and normal tissue, expressed C4 mRNA throughout in the intestinal epithelium. C3 mRNA was not detected in epithelial cells in histologically normal tissue, but in diseased specimens there was a focal distribution of C3 mRNA in epithelial cells of the crypts, but not in villous epithelium. Focal C3 gene expression correlated with crypt abscess formation and the presence of polymorphonuclear leucocytes in the lumen of the crypts. In addition, C3 mRNA was also found in macrophages of the submucosa. These macrophages were CD68+, fusiform with faint cytoplasm and morphologically different from the large rounded lamina propria macrophages, which do not express C3 mRNA. Multinucleated giant cells did not express either C3 or C4 genes. In addition to its presence in intestinal epithelium, C4 mRNA was also expressed in mast cells, which however did not express C3 mRNA. These observations identify cells in the intestinal wall expressing complement genes and support the hypothesis that there is local regulated production of complement in the intestine of patients with CD, and subsequent complement activation may contribute to the inflammatory process.     

Proliferation and differentiation of fetal liver epithelial progenitor cells after transplantation into adult rat liver

To identify cells that have the ability to proliferate and differentiate into all epithelial components of the liver lobule, we isolated fetal liver epithelial cells (FLEC) from ED 14 Fischer (F) 344 rats and transplanted these cells in conjunction with two-thirds partial hepatectomy into the liver of normal and retrorsine (Rs) treated syngeneic dipeptidyl peptidase IV mutant (DPPIV(-)) F344 rats. Using dual label immunohistochemistry/in situ hybridization, three subpopulations of FLEC were identified: cells expressing both alpha-fetoprotein (AFP) and albumin, but not CK-19; cells expressing CK-19, but not AFP or albumin, and cells expressing AFP, albumin, and cytokeratins-19 (CK-19). Proliferation, differentiation, and expansion of transplanted FLEC differed significantly in the two models. In normal liver, 1 to 2 weeks after transplantation, mainly cells with a single phenotype, hepatocytic (expressing AFP and albumin) or bile ductular (expressing only CK-19), had proliferated. In Rs-treated rats, in which the proliferative capacity of endogenous hepatocytes is impaired, transplanted cells showed mainly a dual phenotype (expressing both AFP/albumin and CK-19). One month after transplantation, DPPIV(+) FLEC engrafted into the parenchyma exhibited an hepatocytic phenotype and generated new hepatic cord structures. FLEC, localized in the vicinity of bile ducts, exhibited a biliary epithelial phenotype and formed new bile duct structures or were incorporated into pre-existing bile ducts. In the absence of a proliferative stimulus, ED 14 FLEC did not proliferate or differentiate. Our results demonstrate that 14-day fetal liver contains lineage committed (unipotential) and uncommitted (bipotential) progenitor cells exerting different repopulating capacities, which are affected by the proliferative status of the recipient liver and the host site within the liver where the transplanted cells become engrafted. These findings have important implications in future studies directed toward liver repopulation and ex vivo gene therapy.     

Effect of intermittent fasting on circadian rhythms in mice depends on feeding time

Calorie restriction (CR) resets circadian rhythms and extends life span. Intermittent fasting (IF) also extends life span, but its affect on circadian rhythms has not been studied. To study the effect of IF alongside CR, we imposed IF in FVB/N mice or IF combined with CR using the transgenic FVB/N alphaMUPA mice that, when fed ad libitum, exhibit spontaneously reduced eating and extended life span. Our results show that when food was introduced during the light period, body temperature peak was not disrupted. In contrast, IF caused almost arrhythmicity in clock gene expression in the liver and advanced mPer2 and mClock expression. However, IF restored the amplitudes of clock gene expression under disruptive light condition regardless whether the animals were calorically restricted or not. Unlike daytime feeding, nighttime feeding yielded rhythms similar to those generated during ad libitum feeding. Taken together, our results show that IF can affect circadian rhythms differently depending on the timing of food availability, and suggest that this regimen induces a metabolic state that affects the suprachiasmatic nuclei (SCN) clock.     

Epstein–Barr virus antibodies mark systemic lupus erythematosus and scleroderma patients negative for anti‐DNA

Systemic lupus erythematosus (SLE) is an autoimmune disease that can attack many different body organs; the triggering event is unknown. SLE has been associated with more than 100 different autoantibody reactivities – anti‐dsDNA is prominent. Nevertheless, autoantibodies to dsDNA occur in only two‐thirds of SLE patients. We previously reported the use of an antigen microarray to characterize SLE serology. We now report the results of an expanded study of serology in SLE patients and scleroderma (SSc) patients compared with healthy controls. The analysis validated and extended previous findings: two‐thirds of SLE patients reacted to a large spectrum of self‐molecules that overlapped with their reactivity to dsDNA; moreover, some SLE patients manifested a deficiency of natural IgM autoantibodies. Most significant was the finding that many SLE patients who were negative for autoantibodies to dsDNA manifested abnormal antibody responses to Epstein–Barr virus (EBV): these subjects made IgG antibodies to EBV antigens to which healthy subjects did not respond or they failed to make antibodies to EBV antigens to which healthy subjects did respond. This observation suggests that SLE may be associated with a defective immune response to EBV. The SSc patients shared many of these serological abnormalities with SLE patients, but differed from them in increased IgG autoantibodies to topoisomerase and centromere B; 84% of SLE patients and 58% of SSc patients could be detected by their abnormal antibodies to EBV. Hence an aberrant immune response to a ubiquitous viral infection such as EBV might set the stage for an autoimmune disease.     

Blood pressure reaction to negative stimuli: Insights from continuous recording and analysis

Individuals with a tendency toward abnormally enhanced cardiovascular responses to stress are at greater risk of developing essential hypertension later in life. Accurate profiling of continuous blood pressure (BP) reactions in healthy populations is crucial for understanding normal and abnormal emotional reaction patterns. To this end, we examined the continuous time course of BP reactions to aversive pictures among healthy participants. In two experiments, we showed participants negative and neutral pictures while simultaneously measuring their continuous BP and heart rate (HR) reactions. In this study, BP reactions were analyzed continuously, in contrast to previous studies, in which BP responses were averaged across blocks. To compare time points along a temporal continuum, we applied a multi-level B-spline model, which is innovative in the context of BP analysis. Additionally, HR was similarly analyzed in order to examine its correlation with BP. Both experiments revealed a similar pattern of BP reactivity and association with HR. In line with previous studies, a decline in BP and HR levels was found in response to negative pictures compared to neutral pictures. In addition, in both conditions, we found an unexpected elevation of BP toward the end of the stimuli exposure period. These findings may be explained by the recruitment of attention resources in the presence of negative stimuli, which is alleviated toward the end of the stimulation. This study highlights the importance of continuous measurement and analysis for characterizing the time course of BP reactivity to emotional stimuli.