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Biomedical subjects

Anna Simon

Publications and source records attributed to Anna Simon.

13 recordsLinked to original sources
PubMed2006

Defective apoptosis of peripheral-blood lymphocytes in hyper-IgD and periodic fever syndrome.

Hereditary periodic fever syndromes are characterized by incapacitating attacks of fever and generalized inflammation. While the mutated genes for the major syndromes in this group are known, the pathogenesis remains unclear. The aim of this study was to investigate apoptosis in patients with periodic fever as a possible pathogenic factor. We measured anisomycin-induced apoptosis with annexin-V flow cytometry and caspase-3/7 activity in peripheral-blood lymphocytes from symptom-free patients with hyper-IgD and periodic fever syndrome (HIDS; n = 10), TNF-receptor-associated periodic syndrome (TRAPS; n = 7), and familial Mediterranean fever (FMF; n = 2). HIDS lymphocytes showed a decreased percentage of apoptosis during remission by both methods compared with controls (17.8% vs 55.4%), whereas no difference was observed in TRAPS or FMF lymphocytes. This defective apoptosis of lymphocytes may be a central pathogenic mechanism in HIDS, since dysfunction of one of the inhibitory mechanisms to curtail the immunologic response could cause an unbridled generalized inflammation after a trivial stimulus.

Adolescent↗
PubMed2006

Pathogenesis of familial periodic fever syndromes or hereditary autoinflammatory syndromes.

Familial periodic fever syndromes, otherwise known as hereditary autoinflammatory syndromes, are inherited disorders characterized by recurrent episodes of fever and inflammation. The general hypothesis is that the innate immune response in these patients is wrongly tuned, being either too sensitive to very minor stimuli or turned off too late. The genetic background of the major familial periodic fever syndromes has been unraveled, and through research into the pathophysiology, a clearer picture of the innate immune system is emerging. After an introduction on fever, interleukin-1beta and inflammasomes, which are involved in the majority of these diseases, this manuscript offers a detailed review of the pathophysiology of the cryopyrin-associated periodic syndromes, familial Mediterranean fever, the syndrome of pyogenic arthritis, pyoderma gangrenosum and acne, Blau syndrome, TNF-receptor-associated periodic syndrome and hyper-IgD and periodic fever syndrome. Despite recent major advances, there are still many questions to be answered regarding the pathogenesis of these disorders.

Animals↗
PubMed2005

Gap-junctional coupling between neurogliaform cells and various interneuron types in the neocortex.

Electrical synapses contribute to the generation of synchronous activity in neuronal networks. Several types of cortical GABAergic neurons acting via postsynaptic GABA(A) receptors also form electrical synapses with interneurons of the same class, suggesting that synchronization through gap junctions could be limited to homogenous interneuron populations. Neurogliaform cells elicit combined GABA(A) and GABA(B) receptor-mediated postsynaptic responses in cortical pyramidal cells, but it is not clear whether neurogliaform cells are involved in networks linked by electrical coupling. We recorded from pairs, triplets, and quadruplets of cortical neurons in layers 2 and 3 of rat somatosensory cortex (postnatal day 20-35). Neurogliaform cells eliciting slow IPSPs on pyramidal cells also triggered divergent electrical coupling potentials on interneurons. Neurogliaform cells were electrically coupled to other neurogliaform cells, basket cells, regular-spiking nonpyramidal cells, to an axoaxonic cell, and to various unclassified interneurons showing diverse firing patterns and morphology. Electrical interactions were mediated by one or two electron microscopically verified gap junctions linking the somatodendritic domain of the coupled cells. Our results suggest that neurogliaform cells have a unique position in the cortical circuit. Apart from eliciting combined GABA(A) and GABA(B) receptor-mediated inhibition on pyramidal cells, neurogliaform cells establish electrical synapses and link multiple networks formed by gap junctions restricted to a particular class of interneuron. Widespread electrical connections might enable neurogliaform cells to monitor the activity of different interneurons acting on GABA(A) receptors at various regions of target cells.

Action Potentials↗
PubMed2005

Familial Mediterranean fever--a not so unusual cause of abdominal pain.

Familial Mediterranean fever is a hereditary syndrome characterised by recurrent episodes of fever and serositis, resulting in pain in the abdomen, chest, joints and muscles. It is primarily diagnosed in people of Jewish, Arabic, Turkish or Armenian ancestry and is caused by mutations in the gene encoding for pyrin. Abdominal FMF attacks resemble the clinical presentation of 'acute abdomen', with severe abdominal pain and rigidity, but in FMF symptoms always resolve spontaneously. It is important to distinguish these regular pain episodes from small bowel obstruction due to adhesions to prevent life-threatening bowel strangulation. In most cases, colchicine will prevent new painful attacks. This seminar also discusses other causes of abdominal pain in FMF patients.

Abdominal Pain↗
PubMed2004

Simvastatin treatment for inflammatory attacks of the hyperimmunoglobulinemia D and periodic fever syndrome.

Hyperimmunoglobulinemia D (hyper-IgD) and periodic fever syndrome, a hereditary autoinflammatory syndrome, is characterized by lifelong recurrent episodes of fever and inflammation. No effective treatment is known. It is caused by a defect of mevalonate kinase, an enzyme that follows 3'-hydroxy-3'-methylglutaryl-coenzyme A (HMG-CoA) reductase in the isoprenoid pathway. We wanted to test the hypothesis that inhibition of HMG-CoA reductase would ameliorate the inflammatory attacks. Six patients with hyper-IgD syndrome and proven mevalonate kinase deficiency were followed up for 2 treatment periods with either simvastatin, 80 mg/d, or placebo for 24 weeks, separated by a 4-week washout period in a double-blind fashion. Simvastatin resulted in a drop in urinary mevalonic acid concentration in all patients and decreased the number of febrile days in 5 of 6 patients. No side effects were observed. These data offer preliminary evidence for the hypothesis that simvastatin may improve inflammatory attacks in the hyper-IgD syndrome. This highlights the anti-inflammatory properties of HMG-CoA reductase inhibition.

Adolescent↗
PubMed2003

Increased salt- and nisin-sensitivity of pressure-injured bioluminescent Listeria monocytogenes.

Suspensions of a bioluminescent (luxAB) transformant of Listeria monocytogenes in pH 7.0 phosphate buffer were pressurised and the effect of the pressure treatment was monitored by plate counting. When the bacteria were suspended in NaCl- and nisin-free buffer the number of colony forming units (CFU) decreased by 3 and 6 log cycles after 300 MPA for 10 and 30 min, respectively. Supplementing the plating medium with 5% NaCl did not influence the colony forming capacity of non-pressurised cells, however, CFU of residual populations after respective treatments of 300 MPa for 10 and 30 min were reduced by a further 2 and 3.5 log cycles in case of salt containing plates. Nisin-addition to the plating medium caused less than one log unit decrease in the CFU of the non-pressurised population. However, the CFU of 10 min-pressurised sample was 4 log cycles less in the nisin-containing plates than in the nisin-free ones, whereas no colonies were formed in the nisin-containing plates even when 1 ml was inoculated from the originally 10(10) CFU/ml population after 300 MPa for 30 min. The luciferase activities (bioluminescence intensities) decreased concomitant with the reduction of the viable cell counts, however, they were approx. 0.6-0.8 log units less in the presence of 5% NaCl in the pressurised suspension than those expected from the previously established linear correlation between the logarithmic light outputs and the logarithmic viable cell counts.

Colony Count, Microbial↗
PubMed2003

Neonatal hypernatraemic dehydration and malnutrition associated with inadequate breastfeeding and elevated breast milk sodium.

The advantages of breastfeedng to both the mother and infant are well recognised. In rare instances if breasteding is inadequate or if the sodium content bast milk is high, malnutrition and hypernatraemia can result. A 15 days old exclusively breastfed baby presented with inadequate weight gain. On evaluation, he was found to have hypernatraemia and mother's breast milk showed high sodium concentrations. The infant needed parenteral fluid for correction of dehydration and hypernatraemia. His serum sodium and breast milk sodium of the other of the mother returned to normal gradually. He started gaining weight on exclusive breastfeeds. The present paper describes the case report and brief review of the literature.

Breast Feeding↗