Rendimiento diagnóstico de un nuevo software de aprendizaje profundo para corrección de atenuación en la imagen de perfusión miocárdica utilizando una cámara CZT cardiodedicada. Experiencia en la práctica clínica / Diagnostic performance of a novel deep learning attenuation correction software for MPI using a cardio dedicated CZT camera: Experience in the clinical practice

Objetivo Evaluar el rendimiento diagnóstico de un nuevo software de aprendizaje profundo para corrección de atenuación (SAPCA) en imágenes de perfusión miocárdica (IPM) utilizando una cámara cardiodedicada de cadmio-cinc-telurio (CZT) con correlación con angiografía coronaria (AC) para el diagnóstico de enfermedad arterial coronaria (EAC) en una población de alto riesgo. Métodos Estudio retrospectivo de 300 pacientes (196 varones [65%], edad media de 68 años) desde septiembre de 2014 hasta octubre de 2019. Posteriormente realizaron una IPM, seguida de AC dentro de los 6 meses posteriores a la IPM. La probabilidad media pretest para EAC según los criterios de la Sociedad Europea de Cardiología fue del 37%. La IPM se realizó en una cámara CZT cardio dedicada (D-SPECT® Spectrum Dynamics) usando un protocolo de 2 días, de acuerdo con las guías de la Sociedad Europea de Medicina Nuclear (EANM). La IPM fue evaluada con y sin el SAPCA. Resultados La precisión diagnóstica global de la IPM sin el SAPCA para identificar pacientes con cualquier EAC obstructiva en la AC fue del 87%, sensibilidad del 94%, especificidad del 57%, valor predictivo positivo del 91% y valor predictivo negativo del 64%. Utilizando el SAPCA, la precisión diagnóstica global fue del 90%, la sensibilidad del 91%, la especificidad del 86%, el valor predictivo positivo del 97% y el valor predictivo negativo del 66%. Conclusión El uso del novel SAPCA mejora el rendimiento diagnóstico de la IPM usando la cámara CZT D-SPECT®, especialmente reduciendo el número de resultados falsos positivos al reducir los artefactos (AU)

urpose To evaluate the diagnostic performance of a novel deep learning attenuation correction software (SAPCA) for myocardial perfusion imaging (MPI) using a cadmium-zinc-telluride (CZT) cardio dedicated camera with invasive coronary angiography (ICA) correlation for the diagnosis of coronary artery disease (CAD) in a high-risk population. Methods Retrospective study of 300 patients (196 males [65%], mean age 68 years) from September 2014 to October 2019 undergoing MPI, followed by ICA and evaluated by means of quantitative angiography software, within six months after the MPI. The mean pre-test probability score for coronary disease according to the European Society of Cardiology criteria was 37% for the whole cohort. The MPI was performed in a dedicated CZT cardio camera (D-SPECT® Spectrum Dynamics) with a two-day protocol, according to the European Association of Nuclear Medicine guidelines. MPI was retrospectively evaluated with and without the SAPCA. Results The overall diagnostic accuracy of MPI without SAPCA to identify patients with any obstructive CAD at ICA was 87%, Sensitivity 94%, Specificity 57%, positive predictive value 91% and negative predictive value 64%. Using SAPCA the overall diagnostic accuracy was 90%, sensitivity 91%, specificity 86%, positive predictive value 97% and negative predictive value 66%. Conclusion Use of the novel SAPCA enhances performance of the MPI using the CZT D-SPECT® camera and achieves improved results, especially avoiding artefacts and reducing the number of false positive results (AU)

Prevalence of herpes simplex virus type 1 glycoprotein G (gG) and gI genotypes in patients with herpetic keratitis.

AIM: Recent phylogenetic analyses on the herpes simplex virus type 1 (HSV-1) genes US4, encoding glycoprotein G (gG) and US7, encoding gI, of clinical HSV-1 isolates have led to the classification of HSV-1 into three genotypes, arbitrarily designated as A, B and C. The prevalence of the HSV-1 gG and gI genotypes and their potential disease association was determined in a large cohort of patients with herpetic keratitis (HK). METHODS: Primary corneal HSV-1 isolates of 178 HK patients were genotyped by a PCR-based restriction fragment length polymorphism method targeting the viral genes US4 and US7. RESULTS: Genotype B was more frequently expressed by the corneal HSV-1 isolates compared with genotypes A and C. Fifty-five of 178 corneal isolates (31%) had different genotypes in both loci. No clinically relevant associations were observed between the HSV-1 genotypes and disease outcome in the HK patients studied. CONCLUSIONS: The data presented demonstrate a high frequency of recombinant corneal HSV-1 isolates and suggest that clinical outcome of HSV-1-induced keratitis is independent of a gG or gI genotype.

New upper limit on the total neutrino mass from the 2 degree field galaxy redshift survey.

We constrain f(nu) identical with Omega(nu)/Omega(m), the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2 Degree Field Galaxy Redshift Survey with power spectra for models with four components: baryons, cold dark matter, massive neutrinos, and a cosmological constant. Adding constraints from independent cosmological probes we find f(nu)<0.13 (at 95% confidence) for a prior of 0.1

A measurement of the cosmological mass density from clustering in the 2dF Galaxy Redshift Survey.

The large-scale structure in the distribution of galaxies is thought to arise from the gravitational instability of small fluctuations in the initial density field of the Universe. A key test of this hypothesis is that forming superclusters of galaxies should generate a systematic infall of other galaxies. This would be evident in the pattern of recessional velocities, causing an anisotropy in the inferred spatial clustering of galaxies. Here we report a precise measurement of this clustering, using the redshifts of more than 141,000 galaxies from the two-degree-field (2dF) galaxy redshift survey. We determine the parameter beta = Omega0.6/b = 0.43 +/- 0.07, where Omega is the total mass-density parameter of the Universe and b is a measure of the 'bias' of the luminous galaxies in the survey. (Bias is the difference between the clustering of visible galaxies and of the total mass, most of which is dark.) Combined with the anisotropy of the cosmic microwave background, our results favour a low-density Universe with Omega approximately 0.3.

A summary of reported foodborne disease incidents in Sweden, 1992 to 1997.

Reports of foodborne disease incidents in Sweden from 1992 to 1997 are summarized. The results are based on reports from the municipal environmental and public health authorities to the National Food Administration and from medical authorities to the Swedish Institute for Infectious Diseases Control. A total of 555 incidents, of which 84% were outbreaks, were reported, involving 11,076 ill people. In 66% of the incidents, no disease agent was determined. Bacterial agents were implicated in 25% and viruses in 8% of the incidents. Calicivirus was the most reported agent both in terms of incidents and cases. Mixed dishes was the food category most often implicated in outbreaks, and smorgasbord and casserole or stews were the subcategories that caused the most cases. The place of consumption was unknown in 8% of the incidents. In about 60% of the incidents, the implicated food was consumed in commercial food establishments; in approximately 20% of incidents, it was consumed at home. The average annual incidence of reported foodborne disease in Sweden was estimated to be 21 cases per 100,000. The average annual incidence of reported foodborne salmonellosis and campylobacteriosis was estimated to be 2.0 and 0.6 cases per 100,000, respectively. The awareness and motivation to report foodborne diseases need to be improved, but additional sources of information are needed to counteract some of the limitations of reporting discussed in this work.

Tropospheric ozone decreases biomass production in radish plants (Raphanus sativus) grown in rural south-west Sweden.

Potted plants of radish (Raphanus sativus L., cv. Cherry Belle) were grown in the ambient air for 5 weeks, with or without the application of a soil drench of the anti-ozonant ethylenediurea (EDU). The 24-h mean ozone concentration during the experimental period was 31 nl l(-1). Towards the end of the experiment two ozone episodes, with maximum concentrations around 70 and 115 nl l(-1), occurred. No visible injury that could be attributed to ozone was observed on any of the plants. Shoot and hypocotyl biomass were significantly lower in the non-EDU-treated plants than in the EDU-treated plants. The non-EDU-treated plants had a 32% lower hypocotyl biomass and a 22% lower shoot biomass. The shoot:hypocotyl ratio of the non-EDU-treated plants was higher than that of the EDU-treated plants, although the difference was not statistically significant. EDU treatment increased the leaf area and decreased the chlorophyll content of the leaves. These differences were, however, not statistically significant. It is suggested that the ambient rural ozone climate in southern Sweden has the potential to decrease biomass production in Cherry Belle radishes in the absence of visible injury.

Detection of Yersinia enterocolitica in food by PCR amplification.

A polymerase chain reaction (PCR) assay was developed for detection of pathogenic, virulent strains of Yersinia enterocolitica. By using both virulence loci virF and ail as markers for pathogenicity, detection of species with a virulence factor present was possible. DNA preparation in the presence of hexadecyl trimethy ammonium bromide (CTAB) was followed by two 44 cycle amplification reactions, one for each of the markers. As few as 10(2) Y. enterocolitica cells were detected in ground pork in the presence of 10(5)-10(6) bacteria of other species. The described PCR assay provides a sensitive robust assay for the detection of virulent Y. enterocolitica in food.

A comparison between a PCR method and a conventional culture method for detecting pathogenic Yersinia enterocolitica in food.

The aim of this study was to develop a polymerase chain reaction (PCR) method for the detection of pathogenic Yersinia enterocolitica and to compare it with an official culture method (NMKL-117). Primers were selected for nested PCR directed at the attachment invasion locus, ail, on the bacterial chromosome, as well as at a sequence on the pathogenic marker plasmid, termed virulence factor, virF. The final results obtained by the two methods were similar. However, while the conventional method yielded contradictory data for some steps the PCR method provided unambiguous results. Considerable advantages, i.e. higher sensitivity and specificity of the PCR method, compared with the conventional method for detecting pathogenic Y. enterocolitica, were demonstrated in this study.

Comparison between a cultural procedure using Rappaport-Vassiliadis broth and motility enrichments on modified semisolid Rappaport-Vassiliadis medium for Salmonella detection from food and feed.

Motility enrichment on modified semisolid Rappaport-Vassiliadis (MSRV) medium was evaluated for a rapid Salmonella detection in naturally contaminated food- and feed samples. The results of this procedure were compared with a conventional cultural procedure using Rappaport-Vassiliadis (RV) broth as selective enrichment and modified brilliant green-, xylose lysine desoxycholate- and mannitol lysine crystal violet brilliant green agar for selective plating. The productivity of motility enrichment was 87% compared to a productivity of 99% for the cultural procedure. Statistical analysis showed that there was a significant difference at the 5% level. The present study shows that a combination of direct motility enrichment with the cultural procedure could be used as a very rapid and highly cost-efficient method for Salmonella detection.

Glucosylceramides of oat root plasma membranes--physicochemical behaviour in natural and in model systems.

Glucosylceramides from oat root plasma membranes have been characterized using HPLC-particle beam-mass spectrometry, differential scanning calorimetry, low angle X-ray diffraction and surface balance technique. 24:1-OH was dominating fatty acid (90%) together with 24:0-OH and 22:1-OH. The sphingosine base was sphingadienine isomers and the monosaccharide alpha and beta glucose. Differential scanning calorimetry of an aqueous dispersion of glucosylceramide revealed during heating an endothermic gel-liquid crystalline transition with double peaks at 47 degrees and 51 degrees C, the lowest known for naturally occurring glucosylceramides. A cooling scan after the endothermic gel-liquid transition showed one exotherm at 15 degrees C and if this was followed by another heating scan a large exotherm appeared with a peak at 18 degrees C. During the second heating the matrix was hydrated and the exotherm at 18 degrees C reflects then the transition between the supercooled metastable gel phase and the corresponding hydrated form. The calorimetric data indicate a lamellar phase which during the cooling scan appeared as an supercooled liquid crystalline phase. Low angle X-ray diffraction confirmed these calorimetric data. The surface pressure-area-curves of pure oat glucosylceramides were more expanded than those of bovine origin. Mixtures of oat glucosylceramides and phosphatidylcholine species similar to those present in oat root plasma membranes showed molecular miscibility but no interaction.

Phase behaviour and molecular species composition of oat root plasma membrane lipids. Influence of induced dehydration tolerance.

Tolerance to dehydration induced by repeated water-deficit stress is well correlated to changes in the lipid composition of oat root cell plasma membranes. The molecular species of the two dominant phospholipids phosphatidylcholine and phosphatidylethanolamine were determined. The four major species were 16:0/18:2, 16:0/18:3, 18:2/18:2 and 18:2/18:3. In contrast to the large changes in plasma membrane lipid composition in other respects, induced tolerance resulted in very weak alterations concerning the phospholipid molecular species pattern. Only minor alterations, appearing as a decrease in the 18:3-containing lipids, occurred. Total lipids of microsomes and isolated plasma membranes of root cells were analysed by X-ray crystallography at different degrees of hydration. The lipid phase behaviour at different degrees of hydration was further confirmed by polarization microscopy. In the presence of excess water all membrane lipids adopted a reversed micellar configuration. The plasma membrane lipids from root cells with induced dehydration tolerance formed upon dehydration two coexisting lamellar structures. The importance of the phase behaviour at different degrees of hydration for the membrane properties and the relation to membrane composition is discussed.

Lipids of plasma membranes prepared from oat root cells : effects of induced water-deficit tolerance.

Plasma membranes were isolated from oat (Avena sativa) roots by the phase-partitioning method. The membranes were exposed to repeated periods of moderate water-deficit stress, and a water-deficit tolerance was induced (acclimated plants). The plasma membranes of the controls (nonacclimated plants) were characterized by a high phospholipid content, 79% of total lipids, cerebrosides (9%) containing hydroxy fatty acids (>90% 24:1-OH) and free sterols, acylated sterylglucosides, sterylglucosides, and steryl esters, together amounting to 12%. Major phospholipids were phosphatidylcholine and phosphatidylethanolamine with lesser amounts of phosphatidylglycerol, phosphatidylinositol, and phosphatidic acid. After the membranes were acclimated to dehydration, the lipid to protein ratio decreased from 1.3 to 0.7 micromoles per milligram. Furthermore, the cerebrosides decreased to 5% and free sterols increased from 9% (nonacclimated plants) to 14%. Because the total phospholipids did not change significantly, the free sterol to phospholipid ratio increased from 0.12 to 0.19. There was no change in the relative distribution of sterols after acclimation. The ratio of phosphatidylcholine to phosphatidylethanolamine changed from 1.1 in the nonacclimated plants to 0.69 in the acclimated plants. The results show that acclimation to dehydration implies substantial alterations in the lipid composition of the plasma membrane.

Characterization of glucosylceramide from plasma membranes of plant root cells.

Plasma membranes of oat root cells were isolated from intracellular membranes by subfractionation of the microsomal fraction using an aqueous polymer two-phase system. The plasma membranes originated from oat plants which were acclimated to dehydration by exposure to a repeated water-deficit stress program. Glucosylceramides was a major component of the plasma membrane lipids and amounted to 9% of the lipid of control plants and 5% of the lipid of acclimated plants. Structural analysis using FAB-MS showed only one type of glucosylceramides. The constituent monosaccharide was exclusively glucose and the sphingosine base was 4,8-sphingadienine. The fatty acid composition was determined to 24:1-OH, with only trace levels of non-hydroxy acids. The decrease in the level of glucosylceramides during acclimation to dehydration was accompanied by a corresponding decrease in phospholipids and increase in free sterols.

The effect of incubation temperature and magnesium chloride concentration on growth of salmonella in home-made and in commercially available dehydrated Rappaport-Vassiliadis broths.

Growth rate of salmonellas in Rappaport-Vassiliadis broth (RV) decreased with higher temperature when incubated at 40, 42 and 43 degrees C. Home-made RV and RV-Merck were less inhibitory than RV-Oxoid and RV-lab m. At 43 degrees C growth of all strains of Salmonella dublin were almost completely inhibited in all types of RV. In home-made RV and RV-Merck incubated at 42 degrees C, Salm. dublin was not inhibited any more than other serotypes tested. Variations in growth rate between different types of RV could be explained by differences in concentration of MgCl2. RV with higher MgCl2-concentration were most inhibitory. It is proposed that RV should be incubated at 41.5 +/- 0.5 degrees C (42.0 +/- 0.1 degrees C in a waterbath) and that the amount of MgCl2.6H2O should be approximately 28.6 g/l of the ready-to-use medium, which corresponds to the formula in the original description.

Freeze-dried mixed cultures as samples for proficiency tests and collaborative studies in food microbiology.

A method is presented for preparing samples of freeze-dried mixtures of microorganisms for proficiency tests and collaborative studies. The samples may include most microorganisms that are found in routine analysis in food laboratories. Transport of samples during 48 h did not decrease the number of microorganisms, nor was the variability among samples significantly affected by transport. The standard deviation of counts after 5 weeks of storage varied from 0.04 (Staphylococcus aureus) to 0.17 (Clostridium perfringens) log unit. Storage of samples for 10 weeks decreased the number of viable organisms by 0.02-0.43 log unit. Variability among samples increased for Providencia alcalifaciens and Bacillus cereus after 10 weeks of storage. No significant increase was found for the other organisms.

Enteropathogenic bacteria in frozen chicken.

Eighty-two samples of frozen chicken from retail stores were examined for the presence of Campylobacter, Yersinia enterocolitica, and salmonellae. Aerobic plate counts and numbers of coliform bacteria at 37 degrees C were determined. Campylobacter fetus subsp. jejuni was found in 22% of the samples, Y. enterocolitica was found in 24.5% and Salmonella typhimurium was found in one sample (1.2%). The isolated strains of Y. enterocolitica belonged to serotypes 4, 5b, 6, and 8. Aerobic plate counts and numbers of coliform bacteria at 37 degrees C were not found to be noticeably higher in samples containing pathogens than in pathogen-free samples. This investigation showed that chicken does contain other pathogenic bacteria than salmonellae. Campylobacter and Y. enterocolitica were isolated in much higher frequencies than Salmonella.

Kinetics and regulation of the salt-dependent aspartate transcarbamylase of Halobacterium cutirubrum.

Properties of the aspartate transcarbamylase of the extremly halophilic bacterium Halobacterium cutirubrum, an enzyme that needs high salt concentrations for activity and regulation, were studied in cell-free extracts. The enzyme was stable on prolonged incubation at 4 C in concentrated extracts (50 mg of protein per ml) but not in diluted extracts. Mg(2+) ions and beta-mercaptoethanol stabilized enzyme activity. At salt concentrations below the maximum for activity (3.5 m), the enzyme was rapidly inactivated. Carbamyl phosphate stabilized the enzyme under these conditions; aspartate had a smaller effect. The enzyme was most stable at 0 C; raising or lowering the temperature from this point increased the rate of inactivation. On exposure to lowered salt concentrations, enzyme activity was more sensitive than feedback inhibition. Hyperbolic substrate saturation curves were found for carbamyl phosphate. The K(m) obtained varied with the salt concentration used. With aspartate, sigmoidal curves were found when extracts were assayed immediately after preparation, but hyperbolic curves were obtained with extracts allowed to stand 1 to 2 hr. The presence of cytidine triphosphate (CTP) decreased the V(max) but did not change the K(m); this is thus a V-type enzyme. Low concentrations of succinate activated the enzyme, in the presence and absence of CTP; higher concentrations did not affect its activity. CTP increased the activation energy of the enzyme in 3.5 m salt but decreased it in 2.0 m salt. At both salt concentrations, the sensitivity of the enzyme to feedback inhibition diminished with increasing temperatures. Gel chromatography suggested that the enzyme in crude extracts had a molecular weight of 160,000. Precipitating the enzyme with polyethylene glycol decreased the molecular weight to 34,000, and this activity was no longer sensitive to CTP. The presence of either substrate of the enzyme during polyethylene glycol treatment prevented dissociation of the enzyme and loss of feedback inhibition. Thus, as with other aspartate transcarbamylases, association of subunits seems to be required for regulation of activity by end product.