Comparative assessment of the effects of vasodilators on peripheral vascular reactivity in patients with systemic scleroderma and Raynaud's phenomenon: Color Doppler flow imaging study

PubMedID: 8644944The aim of the present study was assessment of peripheral vascular reactivity during cold test and effects of different types of vasodilators on vascular resistance in patients with progressive systemic sclerosis and Raynaud's phenomenon with use of color Doppler flow imaging of upper extremity

Value of duplex and color doppler ultrasonography in the evaluation of orbital vascular flow and resistance in sickle cell disease

PubMedID: 11391712The aim of the present study was to assess and to compare the orbital and retinal vascular flow dynamics and resistance in patients with homozygous sickle cell disease with controls by means of duplex and color Doppler ultrasonography. Forty-six patients with homozygous sickle cell disease (SCD) and 20 healthy subjects were included in the study. None of the patients had objective signs of ocular involvement. Duplex and color Doppler ultrasonography of the ophthalmic, short posterior ciliary, and central retinal arterial flows of the both eyes were performed to assess peak systolic flow velocity (PSFV), end-diastolic flow velocity (EDFV), and mean flow velocity (MFV) through entire cardiac cycle with further calculation of resistive indices (RI) and pulsatility indices (PI). Ophthalmic arterial flow velocities were significantly increased in patients with SCD than in controls (P < 0.0001). Blood flow velocities of the central retinal artery were found to be significantly reduced (P < 0.0001) while RI and PI values were markedly higher (P < 0.02 and P < 0.03) in patients with SCD compared to controls. Reduction of retinal vascular flow velocities and increase of retinal vascular resistance were significantly related to the mean hemoglobin and hematocrit levels, red blood cell count, and mean corpuscular hemoglobin volume (P < 0.009, P < 0.01, P < 0.02, and P < 0.04, respectively). In conclusion, Doppler ultrasonography in patients with SCD who had no objective signs of ocular involvement allowed detection enhancement of ophthalmic flow velocities, reduced retinal flow velocities, and increased retinal vascular resistance, which are associated with haematological features. © 2001 Wiley-Liss, Inc

Prevalence of cardiac arrhythmia and risk factors in chronic kidney disease patients

PubMedID: 29970732Chronic kidney disease (CKD) patients have a high risk for cardiac arrhythmia. This study aimed to investigate the prevalence of cardiac arrhythmia in CKD patients and to evaluate the relationship between arrhythmia and biochemical and echocardiographic parameters. CKD patients between 18 and 80 years of age were enrolled from the nephrology outpatient clinic. Physical examination, complete blood count, urinalysis biochemical analysis, electrocardiogram, echocardiogram, and 24-h Holter electrocardiogram were performed. Patients with and without cardiac arrhythmia were compared regarding their characteristics, laboratory findings, and echocardiographic parameters. Risk factors for cardiac arrhythmia were also evaluated. The carotid intima-media thickness was measured using Doppler ultrasonography. In our study involving 59 patients, 44 (74%) had atrial arrhythmia (AA) and 40 (68%) had ventricular arrhythmia (VA). Atrial and/or VA were diagnosed in 46 patients (78%), of whom six (10.2%) had AA, two (3.4%) had VA and 38 (64.4%) had AA plus VA. Atrial fibrillation (AF) was present in two patients (3.4%) in the form of paroxysmal AF. Risk factors for AA were low calcium level and posterior wall thickness, while factors associated with VA were age, triglyceride level, leukocyte count, and nonusage of angiotensin 2 receptor blockers. Risk factors for AA and/or VA included increased platelet count, age, and leukocyte count. AA and/or VA were found in as high as 78% of CKD patients. Further studies evaluating course of the disease from early stages are needed to identify risk factors

Russian isolates enlarge the known geographic diversity of Francisella tularensis subsp. mediasiatica.

Francisella tularensis, a small Gram-negative bacterium, is capable of infecting a wide range of animals, including humans, and causes a plague-like disease called tularemia-a highly contagious disease with a high mortality rate. Because of these characteristics, F. tularensis is considered a potential agent of biological terrorism. Currently, F. tularensis is divided into four subspecies, which differ in their virulence and geographic distribution. Two of them, subsp. tularensis (primarily found in North America) and subsp. holarctica (widespread across the Northern Hemisphere), are responsible for tularemia in humans. Subsp. novicida is almost avirulent in humans. The fourth subspecies, subsp. mediasiatica, is the least studied because of its limited distribution and impact in human health. It is found only in sparsely populated regions of Central Asia. In this report, we describe the first focus of naturally circulating F. tularensis subsp. mediasiatica in Russia. We isolated and characterized 18 strains of this subspecies in the Altai region. All strains were highly virulent in mice. The virulence of subsp. mediasiatica in a vaccinated mouse model is intermediate between that of subsp. tularensis and subsp. holarctica. Based on a multiple-locus variable number tandem repeat analysis (MLVA), we show that the Altaic population of F. tularensis subsp. mediasiatica is genetically distinct from the classical Central Asian population, and probably is endemic to Southern Siberia. We propose to subdivide the mediasiatica subspecies into three phylogeographic groups, M.I, M.II and M.III

N-acetylcysteine infusion reduces the resistance index of renal artery in the early stage of systemic sclerosis

AIM: To evaluate resistance index (RI) changes in renal artery after N-acetylcysteine infusion in patients with systemic sclerosis. METHODS: In an open-label study 40 patients with systemic sclerosis (SSc) were treated with N-acetylcysteine (NAC) iv infusion over 5 consecutive hours, at a dose of 0.015 g x kg(-1) x h(-1). Renal haemodynamic effects were evaluated by color Doppler examination before and after NAC infusion. RESULTS: NAC infusion significantly reduced RI in a group of sclerodermic patients with early/active capillaroscopic pattern, modified Rodnan Total Skin Score (mRTSS) 14 and severe-end stage score to the vascular domain of DSS. In patients with reduction of RI after NAC infusion, diffusion capacity for carbon monoxide mean value was significantly higher than in those patients with an increase of RI. No significant differences in renal blood flow were found between patients with different subsets of SSc. CONCLUSION: In patients with low disease severity NAC ameliorates vascular renal function

Opportunistic bacteria and mass mortality in ungulates: lessons from an extreme event

Mass mortality events in wildlife are a growing concern. Under conditions of rapid global change, opportunistic responses in bacterial commensals, triggered by environmental stressors, may be increasingly implicated in die-offs. In 2015, over 200,000 saiga antelope died of hemorrhagic septicemia caused by the pathogen Pasteurella multocida serotype B. We use this case to explore die-offs from commensal bacteria more broadly, looking at factors which might favor such extreme events. We review other recorded disease outbreaks caused by Pasteurellaceae organisms, firstly in saiga and secondly in other wild ungulates, and ask whether the 2015 die-off was unprecedented in terms of mortality rates, numbers dead and spatial scale, and in the nature of the predisposing or environmental factors involved. We also compare these outbreaks with mass mortality events associated with commensal bacteria in wildlife more generally. We identify three additional major die-offs in saiga in which Pasteurellaceae organisms may be implicated, of which one in 1988 closely resembles the 2015 hemorrhagic septicemia event. No other recorded cases in wild ungulates approach the magnitude of these cases for any of the metrics considered, possible exceptions being die-offs in Mongolian gazelles, in which the role of these pathogens is poorly substantiated. Environmental triggers were the most commonly suggested factor leading to pathogenesis, with warm humid conditions most commonly associated with hemorrhagic septicemia. Life history may also be significant – saigas are migratory and the largest pasteurellosis outbreaks outside this species also occur in migratory species of bird or other temperate ungulates aggregating in large numbers. Cases provoked by other commensals tend to be small in magnitude. Exceptions involve interactions between multiple pathogens and climatic conditions or sets of climatic conditions acting on different stages of the host-pathogen life cycle, leading to time lags between infection and subsequent disease. Overall, the scale and rapidity of the saiga die-offs appear unprecedented amongst mortality events caused by bacterial commensals in wild mammals. Experimental research into the genetics and micro-biology of host-pathogen interactions upon changes in the external environment, and monitoring of animals and conditions at calving sites, may eventually reveal the underlying causes of these die-offs