Optical Density Ratio Research Articles

The influence of simulated cataract on retinal vessel oximetry measurements.

PurposeTo assess the impact of human crystalline lens opacification and yellowing, similar to that observed in patients with cataracts, on retinal vessel blood oxygen saturation measurements using custom manufactured soft contact lenses.MethodsTen healthy, non‐smoking individuals were enrolled for this study. All subjects underwent digital blood pressure measurements, assessment of non‐contact intra‐ocular pressure, pupil dilation and retinal vessel oximetry using dual‐wavelength photography (Oximetry Module, Imedos Systems). To simulate lens changes, three different contact lenses were inserted, one to simulate opacities followed by two more lenses to simulate different levels of lens yellowing (Cantor & Nissel).ResultsThe measurements obtained showed an opposite change in arterial and venous oxygen saturation and optical density ratio across conditions, resulting in a statistically significant difference in arterial minus venous oxygen saturation value (p = 0.003). However, this difference was only significant for the ‘opacity’ condition but not for the ‘yellowing’ conditions.ConclusionLenticular changes such as cataracts can impact on spectrophotometric analysis in particular dual‐wavelength retinal vessel oximetry. Hence, lenticular assessment and cataract grading should be considered when assessing elderly individuals and patient groups developing cataract earlier in life such as those suffering from diabetes mellitus.

Optical Density of Subretinal Fluid in Retinal Detachment.

To investigate the changes over time in optical density (OD) characteristics of subretinal fluid (SRF) in rhegmatogenous retinal detachment (RRD) and their clinical relevance. The study included patients with first-onset RRD and no history of intraocular illness who underwent optical coherence tomography (OCT) and whose OCT scans showed sufficient SRF for sampling (08/2013-09/2014). The highest quality B-scan (as graded by the OCT image acquisition software) containing SRF was analyzed. Optical density measurements were obtained using ImageJ. Optical density ratios (ODRs) were calculated as SRF OD divided by vitreous OD. Time from onset of RRD was determined by first signs of visual loss as described in the patient's anamnesis. Patients were divided into three groups by RRD duration: acute (≤1 week), subacute (between 1 week and 1 month), and chronic (>1 month). Thirty-five eyes (34 patients) met the inclusion criteria. The ODR measurement was significantly associated with RRD duration. The ODR had a significant (P < 0.0001) association with the 3-month postoperative visual acuity (VA). Vitreous OD did not differ significantly between the three groups. The increase over time in the ODR of the SRF in RRD might reflect a change in SRF composition and state of the retina. This, together with a significant association between preoperative ODR values and postoperative VA suggest its potential as a biological prognostic marker.

In Vivo Capillary Loop Hemoglobin Spectroscopy in Labial, Sublingual, and Periodontal Tissues.

Reproducible estimates of hemoglobin absorption spectra from human capillaroscopy images of arterioles, capillaries, and venules in sublingual and labial mucosa in vivo and venules in the tissues lining the periodontal pocket. By reducing the size of both the imaging lens and the light guide to a maximum 1 mm diameter and opposing them with a gap of 600 μm we have been able to transmit light through the loop of tissues which moves into the gap between the lens and light guide when these are placed in contact with the labial and sublingual oral mucosa. This allows in vivo transillumination of the microvessels supplying the mucosa. Images from five volunteers showed similar patterns and the ratio of optical densities at 410 nm and 430 nm had a range from 2.5 at 90-100% saturation to 0.5 at zero % saturation. Measured optical density ratios ranged from 0.5 to 1.6 ± 0.1 in the afferent arm of the capillary loops and 0.5 to 1.1 ± 0.1 in the efferent arm of the capillary loops. In vivo spectroscopic hemoglobin optical density ratios in oral mucosal microvessels show a qualitatively consistent result within the expected in vitro parameters.

Mitochondrial Sirt3 Expression is Decreased in APP/PS1 Double Transgenic Mouse Model of Alzheimer's Disease.

Emerging data suggests that mitochondrial dysfunction is prominently involved in Alzheimer disease (AD) progression. Sirtuin-3 (Sirt3) is a member of the sirtuin family of nicotinamide adenine dinucleotide dependent deacetylases that regulates a variety of mitochondrial functions and suppresses mitochondria-related physiology. Here, we determined sirt3 expression in a mouse model of AD. Spatial learning and memory were tested by Morris water maze in APP/PS1 double transgenic mice. The expression of sirt3 was assayed by real-time quantitative PCR and western blotting. Age-and gender-matched wild-type (WT) littermates were used as controls. Cortical sirt3 localization was assessed using immunohistochemistry. The expression of sirt3 mRNA was significantly lower in the cortex of APP/PS1 double transgenic mice than in WT littermates (0.83 ± 0.24 vs. 1.10 ± 0.21, P < 0.05). A comparable reduction was found in sirt3 protein levels using western blotting. The ratio of mean optical density (MOD) of total sirt3/β-actin in the cortex was 0.77 ± 0.11 in APP/PS1 double transgenic mice and 1.34 ± 0.17 in the WT littermates (P < 0.01). Immunohistochemistry showed the same change as western blotting. The ratio of MOD of integral optical density/total area in APP/PS1 and WT littermates was 0.58 ± 0.02 and 0.71 ± 0.05 (P < 0.01). These data show that sirt3 was depleted in APP/PS1 double transgenic mice. The results suggest that mitochondrial sirt3 might participate in the development of AD via mitochondrial dysfunction.

Effect of light intensity on the correlation between cell mass concentration and optical density in high density culture of a filamentous microorganism

We investigated the effect of light intensity on the correlation between optical density (OD) and cell mass concentration in high cell density culture of Anabaena variabilis. When the light intensity was gradually increased to maintain specific irradiation rate above 10 mmol/s/g dry cell, the dry cell mass concentration to OD ratio changed when the cell density became higher than OD 10, while the correlation was linear when light intensity remained constant after 2.5 days. When the OD was below 10, the dry cell concentration to OD ratio in unicells was the same as that of filaments, indicating that filament length, unicell size, and unicell dry cell concentration did not affect the dry cell concentration to OD ratio. Scanning electron microscope pictures revealed the differences in morphological structures between filaments below and above OD 10. Therefore, we propose that the morphological structures of filaments affected the dry cell concentration to OD ratio.

Peptide-activated gold nanoparticles for selective visual sensing of virus

In this study, we report peptide–gold nanoparticles (AuNP)-based visual sensor for viruses. Citrate-stabilized AuNP (20 ± 1.9 nm) were functionalized with strong sulfur–gold interface using cysteinylated virus-specific peptide. Peptide–Cys–AuNP formed complexes with the viruses which made them to aggregate. The aggregation can be observed with naked eye and also with UV–Vis spectrophotometer as a color change from bright red to purple. The test allows for fast and selective detection of specific viruses. Spectroscopic measurements showed high linear correlation (R 2 = 0.995) between the changes in optical density ratio (OD610/OD520) with the different concentrations of virus. The new method was compared with the hemagglutinating (HA) test for Newcastle disease virus (NDV). The results indicated that peptide–Cys–AuNP was more sensitive and can visually detect minimum number of virus particles present in the biological samples. The limit of detection for the NDV was 0.125 HA units of the virus. The method allows for selective detection and quantification of the NDV, and requires no isolation of viral RNA and PCR experiments. This strategy may be utilized for detection of other important human and animal viral pathogens.

Modelling the spatial distribution of Fasciola hepatica in dairy cattle in Europe.

A harmonized sampling approach in combination with spatial modelling is required to update current knowledge of fasciolosis in dairy cattle in Europe. Within the scope of the EU project GLOWORM, samples from 3,359 randomly selected farms in 849 municipalities in Belgium, Germany, Ireland, Poland and Sweden were collected and their infection status assessed using an indirect bulk tank milk (BTM) enzyme-linked immunosorbent assay (ELISA). Dairy farms were considered exposed when the optical density ratio (ODR) exceeded the 0.3 cut-off. Two ensemble-modelling techniques, Random Forests (RF) and Boosted Regression Trees (BRT), were used to obtain the spatial distribution of the probability of exposure to Fasciola hepatica using remotely sensed environmental variables (1-km spatial resolution) and interpolated values from meteorological stations as predictors. The median ODRs amounted to 0.31, 0.12, 0.54, 0.25 and 0.44 for Belgium, Germany, Ireland, Poland and southern Sweden, respectively. Using the 0.3 threshold, 571 municipalities were categorized as positive and 429 as negative. RF was seen as capable of predicting the spatial distribution of exposure with an area under the receiver operation characteristic (ROC) curve (AUC) of 0.83 (0.96 for BRT). Both models identified rainfall and temperature as the most important factors for probability of exposure. Areas of high and low exposure were identified by both models, with BRT better at discriminating between low-probability and high-probability exposure; this model may therefore be more useful in practise. Given a harmonized sampling strategy, it should be possible to generate robust spatial models for fasciolosis in dairy cattle in Europe to be used as input for temporal models and for the detection of deviations in baseline probability. Further research is required for model output in areas outside the eco-climatic range investigated.

Longitudinal optical density analysis of subretinal fluid after surgical repair of rhegmatogenous retinal detachment.

To investigate optical coherence tomography-derived reflectivity and optical density (OD) characteristics of persistent subretinal fluid (SRF) in eyes after surgical repair of macula-off rhegmatogenous retinal detachment. Retrospective case series of nine eyes with macula-off rhegmatogenous retinal detachment that underwent surgical repair with either scleral buckling or vitrectomy with or without scleral buckling. Major inclusion criteria included 1) availability of high-quality optical coherence tomography scans at 2 or more time points, and 2) sufficient SRF for optical coherence tomography sampling without including tissue edges. Demographic, clinical, and optical coherence tomography imaging data were collected on all eyes. Optical density and SRF height measurements were obtained using a manual image segmentation method with ImageJ. Optical density measurements were standardized by conversion to optical density ratios to facilitate comparison between different visits and eyes. Correlations were assessed for significance through both univariate and multivariate regression analyses. Optical density ratio measurements increased with time after surgery, and this was statistically significant (P = 0.001, R = 0.331). Subretinal fluid height measurements decreased in all eyes. There was a significant correlation between optical density ratios and log of SRF height (P ≤ 0.001, R = 0.485). In multivariate analysis, neither optical density ratios nor SRF height was a statistically significant predictor of visual acuity. Changes in optical density ratios of the residual SRF after retinal detachment repair may be representative of changes in the SRF composition over time. This is in agreement with previous biochemical studies and may serve as a noninvasive method of assessing SRF content in vivo.

Optical Density Ratio in the Subretinal Fluid: Differentiating Chronic Central Serous Chorioretinopathy and Polypodial Choroidal Vasculopathy

To investigate the differences in the optical density ratios between chronic central serous chorioretinopathy (CSC) and polypoidal choroidal vasculopathy (PCV) obtained from subretinal fluid (SRF) analyses to identify the diagnostic role of optical density ratios. Retrospective cohort study. Patients with acute CSC (n = 36), chronic CSC (n = 38), and PCV (n = 32) were included in the study. Spectral-domain optical coherence tomography (SD OCT) images of SRF were analyzed. The optical density measurements were obtained by using ImageJ. The optical density ratios were calculated from the SRF to the vitreous, retinal pigment epithelium (RPE), and retinal nerve fiber layer (RNFL) reflectivity ratios. Optical density ratios of SRF to the vitreous, RPE, and RNFL were significantly higher in patients with PCV than in those with chronic CSC (P = .002, P = .001, P = .001). There was no significant difference between acute and chronic CSC (P = .358, P = .433, P = .774). RPE reflectivity was significantly different between groups (P = .002) but no significant difference in vitreous and RNFL reflectivity were detected between groups (P = .172, P = .171). The optical density ratio differs significantly between chronic CSC and PCV, but not between chronic and acute CSC. This suggests the usefulness of this parameter in differentiating between chronic CSC resembling PCV and PCV itself.

Evaluation of Human Serological Response to Recombinant TB10.4 Antigen of Mycobacterium tuberculosis

Introduction: Development of effective immunodiagnostic methods for detection of Mycobacterium tuberculosis infection is crucial. Serodiagnostic methods, based on antibody response to specific antigens could provide promising approaches for rapid, economical and easy to perform diagnostic tests which are crucial for tuberculosis (TB) control. In this study, the level of IgG antibody responses against recombinant TB10.4 and Bacille Calmette-Guerin (BCG) in sera from TB patients and vaccinated healthy controls were evaluated. Methods: Indirect ELISA was used to assess the anti-TB10.4 IgG levels. Serum samples were obtained from vaccinated healthy controls, confirmed TB positive patients, TB cases under antibiotic treatment, and cases with atypical mycobacteria infection. The ratio of test sera optical density to the optical density of pooled negative control was taken as cut off value. Results: Using indirect ELISA method, anti-TB10.4 was detected in 64.5%, 93.5%, 85.7% and 100% of the sera from vaccinated healthy controls, confirmed TB positive cases, TB cases under antibiotic treatment and cases with atypical mycobacteria infection, respectively. The relative sensitivity for TB10.4 was calculated as 84.32%. Conclusion: In this study, the use of TB10.4 protein showed high sensitivity, but low specificity in detection of anti-M. tb antibodies in TB patients. These results suggest that further studies should be undertaken to identify the optimal combinations of antigens for the sensitive and specific serodiagnosis of TB.

The effect of silver nanoparticles on Staphylococcus epidermidis biofilm biomass and cell viability

Objective(s): Bacterial biofilm has been considered responsible for many deaths and high health costs worldwide. Their better protection against antibacterial agents compared to free living cells leads to poor treatment efficiency. Nanotechnology is promising approach to combat biofilm infections. The aim of the present study was to eradicate Staphylococcus epidermidis biofilm with silver nanoparticles (SNPs). Materials and Methods: SNPs were used at different concentrations (two fold dilutions) and incubation times (24, 48, 72 h). The crystal violet staining and pour plate assays were used to assess biofilm biomass and bacterial viability, respectively. The ability of SNPs on biofilm matrix eradication was assessed through optical density ratio (ODr). Positive control was defined as an ODr =1.0. Results: The crystal violet assay indicated that the biofilm matrixes were intact at different concentrations of SNOs and incubation times. There were no significant differences between these parameters (P >0.05). Bacterial enumeration studies revealed that higher concentrations of SNPs were more effective in killing bacteria than lower ones. Although, longer incubation times led to enhancement of anti-biofilm activity of SNPs. Conclusion: The anti-biofilm activity of SNPs was concentration- and time-dependent. The results of this study highlighted that SNPs were effective against cell viability; however they were ineffective against biomass.

Novel extraction method of genomic DNA suitable for long-fragment amplification from small amounts of milk

Isolation of genomic DNA is a prerequisite for assessment of milk quality. As a source of genomic DNA, milk somatic cells from milking ruminants are practical, animal friendly, and cost-effective sources. Extracting DNA from milk can avoid the stress response caused by blood and tissue sampling of cows. In this study, we optimized a novel DNA extraction method for amplifying long (>1,000 bp) DNA fragments and used it to evaluate the isolation of DNA from small amounts of milk. The techniques used for the separation of milk somatic cell were explored and combined with a sodium dodecyl sulfate (SDS)-phenol method for optimizing DNA extraction from milk. Spectrophotometry was used to determine the concentration and purity of the extracted DNA. Gel electrophoresis and DNA amplification technologies were used for to determine DNA size and quality. The DNA of 112 cows was obtained from milk (samples of 13±1mL) and the corresponding optical density ratios at 260:280 nm were between 1.65 and 1.75. Concentrations were between 12 and 45μg/μL and DNA size and quality were acceptable. The specific PCR amplification of 1,019- and 729-bp bovine DNA fragments was successfully carried out. This novel method can be used as a practical, fast, and economical mean for long genomic DNA extraction from a small amount of milk.

Expression of TFPI-2 gene and its promoter methylation in acute myeloid leukemia

The aim of this study was to detect the mRNA expression of tissue factor pathway inhibitor-2 ( TFPI-2) and its methylation in bone marrow mononuclear cells from acute myeloid leukemia (AML) patients and to explore its significance in AML. Bone marrow mononuclear cells were isolated from newly diagnosed AML patients (n = 33), complete remission AML patients (n = 19), relapsed/refractory AML patients (n = 12) and iron deficiency anemia patients (control group, n = 15). Expression of TFPI-2 mRNA was detected with real-time quantitative PCR (RT-PCR) and the methylation of CpG island in its promoter was detected with methylation-specific PCR (MSP). The results showed that the expression of TFPI-2 mRNA in newly diagnosed AML, complete remission AML and relapsed/refractory AML patients was much lower than that in the controls (P < 0.05). Furthermore, its expression in relapsed/refractory AML patients was lower than that in newly diagnosed AML patients (P = 0.006). Compared with complete remission AML patients, the expression of TFPI-2 mRNA in newly diagnosed AML patients was significantly reduced (P = 0.030). The percentage of TFPI-2 promoter methylation in AML patients was 64.63% (42/64). In newly diagnosed AML group, complete remission AML group and relapsed/refractory AML group,the percentages of TFPI-2 promoter methylation were 66.67% (22/33), 52.63% (10/19) and 83.33% (10/12) (P > 0.05), respectively. The optical density ratio of TFPI-2 mRNA expression was 0.165 (0.005-2.099) in methylated AML patients, and 0.597 (0.011-2.787) in unmethylated AML patients (P < 0.05). Methylation of TFPI-2 gene promoter was not detected in control patients. After 2 courses of chemotherapy, the level of TFPI-2 mRNA was much higher in the CR group than that in the non-CR group (P < 0.05). It is concluded that the down-regulation or silence of TFPI-2 gene potentially results from its promoter methylation, and the expression level of TFPI-2 and the methylation status of its promoter may be used as indicators of risk stratification and evaluation of disease progress.

Annual variation in serum antibody concentrations against gastrointestinal nematodes in beef calves from semi-arid rangelands of western Canada

Sera from calves originating on a 17,000ha ranch in southeastern Alberta, were collected over three consecutive years (2008–2010) at weaning and analysed for the presence of anti-Ostertagia antibodies using the SVANOVIR®Ostertagia ostertagi-Ab ELISA kit. Faecal samples taken at the same time were analysed for presence of nematode eggs using the modified Wisconsin faecal flotation technique. Mean optical density ratio (ODR) values for all calves were similar in 2008 and 2010 while the 2009 values were significantly higher. Similar cumulative frequency distribution profiles were found for 2008 and 2010 while the 2009 profile had an increased number of values in the higher bin categories. This pattern indicates higher nematode transmission on pasture in 2009. There was no significant difference in ODR values between egg positive and egg-negative calves and no significant correlation was detected between individual ODR values and faecal egg output. Significantly higher ODR values in 2009 appear contradictory to general assumptions about the ecological requirements of larval development, as 2009 was a relatively dry year. However, examination of weather data identified 5–6 rainfall events that may have resulted in episodic enhanced survival of nematode larvae.

A tri state mechanism for oxygen release in fish hemoglobin: Using Barbus sharpeyi as a model.

Hemoglobin is a porphyrin containing protein with an α2β2 tetrameric structure and like other porphyrin compounds shows spectral behavior of species specific characteristics. Researchers tend to relate bands in the hemoglobin spectra to certain structural and/or functional features. Given the fact th↔at hemoglobin is the main oxygen carrier in animals functioning through the Oxy↔Deoxy equilibrium, the determination of oxy and deoxy conformations of hemoglobins of different animals may shed light on their oxygen binding properties. Absorption spectra at 280 and 373nm have been widely used to quantitate the formation of hemoglobin deoxy conformation. In the present work, however, we used an optical density ratio of OD373/OD280 as an index for deoxy formation. This ratio was determined for Barbus sharpeyi and human hemoglobins at different SDS concentrations, pH levels and temperatures to compare them from a structure-function point of view. Our data showed that under low concentrations of SDS (<2mM) Barbus sharpeyi hemoglobin folds in a tri-state pattern while human hemoglobin folds through a two-state phenomenon. This finding indicates that in contrast to those of other non aquatic animals, the hemoglobin of Barbus sharpeyi has a loosely folded tetrameric structure with remarkably more oxygen affinity.

Photorelease of La3+ with turn-on fluorescent detection

Abstract Photorelease of La 3+ with turn on fluorescent detection is described. Complex ( 1 ) is synthesized by treatment 2,2′-(((ethane-1,2-diylbis(oxy)bis(2,1-phenylene))bis(methanylylidene)) bis(azanylylidene))diphenol with LaCl 3 ·7H 2 O in 1:1 molar ratio. Upon irradiation with UV light, 1 undergoes La 3+ release and converts to 1,2-bis(2-(benzoxazol-2-yl)phenoxy)ethane ( 2 ). It is found that 2 exhibits strong fluorescence emission and the turn-on fluorescence is detected during the photo-conversion of 1 to 2 , which is beneficial for monitoring the photorelease of La 3+ . Moreover, an excellent ( R = 0.9963) linear correlation between the ratio of optical density (OD 1 /OD 2 ) with irradiation time is obtained when 1 is photo-converted to 2 , which is beneficial for controlling or regulating the quantity of La 3+ -released.

Objective Measurement of Vitreous Inflammation Using Optical Coherence Tomography

To obtain measurements of vitreous signal intensity from optical coherence tomography (OCT) image sets in patients with uveitis, with the aim of developing an objective, quantitative marker of inflammatory activity in patients with this disease. Retrospective, observational case-control series. Thirty patients (30 eyes) with vitreous haze secondary to intermediate, posterior, or panuveitis; 12 patients (12 eyes) with uveitis but without evidence of vitreous haze; and 18 patients (18 eyes) without intraocular inflammation or vitreoretinal disease. Clinical and demographic characteristics were recorded, including visual acuity (VA), diagnosis, and anatomic type of uveitis. In each eye, the anterior chamber (AC) was graded for cellular activity and flare according to standardized protocols. The presence and severity of vitreous haze were classified according to the National Eye Institute system. Spectral-domain OCT images were analyzed using custom software. This software provided an "absolute" measurement of vitreous signal intensity, which was then compared with that of the retinal pigment epithelium (RPE), generating an optical density ratio with arbitrary units ("VIT/RPE-Relative Intensity"). Correlation between clinical vitreous haze scores and OCT-derived measurements of vitreous signal intensity. The VIT/RPE-Relative Intensity was significantly higher in uveitic eyes with known vitreous haze (0.150) than in uveitic eyes without haze or in healthy controls (0.0767, P = 0.0001). The VIT/RPE-Relative Intensity showed a significant, positive correlation with clinical vitreous haze scores (r = 0.566, P = 0.0001). Other ocular characteristics significantly associated with VIT/RPE-Relative Intensity included VA (r = 0.573, P = 0.0001), AC cells (r = 0.613, P = 0.0001), and AC flare (r = 0.385, P = 0.003). Measurement of VIT/RPE-Relative Intensity showed a good degree of intergrader reproducibility (95% limits of agreement, -0.019 to 0.016). These results provide preliminary evidence that OCT-derived measurements of vitreous signal intensity may be useful as an outcome measure in patients with uveitis. If validated in future studies, such measures may serve as an objective, quantitative disease activity end point, with the potential to improve the "signal:noise" ratio of clinical trials in this area, thus enabling smaller studies for the same power. The incorporation of automated vitreous analysis in commercial OCT systems may, in turn, facilitate monitoring and re-treatment of patients with uveitis in clinical practice.

A stochastic frontier approach to study the relationship between gastrointestinal nematode infections and technical efficiency of dairy farms

The impact of gastrointestinal (GI) nematode infections in dairy farming has traditionally been assessed using partial productivity indicators. But such approaches ignore the impact of infection on the performance of the whole farm. In this study, efficiency analysis was used to study the association of the GI nematode Ostertagia ostertagi on the technical efficiency of dairy farms. Five years of accountancy data were linked to GI nematode infection data gained from a longitudinal parasitic monitoring campaign. The level of exposure to GI nematodes was based on bulk-tank milk ELISA tests, which measure the antibodies to O. ostertagi and was expressed as an optical density ratio (ODR). Two unbalanced data panels were created for the period 2006 to 2010. The first data panel contained 198 observations from the Belgian Farm Accountancy Data Network (Brussels, Belgium) and the second contained 622 observations from the Boerenbond Flemish farmers' union (Leuven, Belgium) accountancy system (Tiber Farm Accounting System). We used the stochastic frontier analysis approach and defined inefficiency effect models specified with the Cobb-Douglas and transcendental logarithmic (Translog) functional form. To assess the efficiency scores, milk production was considered as the main output variable. Six input variables were used: concentrates, roughage, pasture, number of dairy cows, animal health costs, and labor. The ODR of each individual farm served as an explanatory variable of inefficiency. An increase in the level of exposure to GI nematodes was associated with a decrease in technical efficiency. Exposure to GI nematodes constrains the productivity of pasture, health, and labor but does not cause inefficiency in the use of concentrates, roughage, and dairy cows. Lowering the level of infection in the interquartile range (0.271 ODR) was associated with an average milk production increase of 27, 19, and 9L/cow per year for Farm Accountancy Data Network farms and 63, 49, and 23L/cow per year for Tiber Farm Accounting System farms in the low- (0–90), medium- (90–95), and high- (95–99) efficiency score groups, respectively. The potential milk increase associated with reducing the level of infection was higher for highly efficient farms (6.7% of the total possible milk increase when becoming fully technically efficient) than for less efficient farms (3.8% of the total possible milk increase when becoming fully technically efficient).

Usefulness of Strongyloides stercoralis Serology in the Management of Patients with Eosinophilia

Strongyloides stercoralis infection is being increasingly diagnosed out of endemic areas. The aim of this study is to evaluate the usefulness of S. stercoralis serology for the management of probable strongyloidiasis in patients presenting with eosinophilia. Overall, 147 patients were included, 89 (60.5%) patients had a positive S. stercoralis serology. Strongyloides stercoralis larvae were detected only in 15 (10.2%) patients. Twenty-eight patients had human immunodeficiency virus infection. Eighty patients received ivermectin 200 mcg/Kg/day for 2 days, and follow-up 6 months after treatment could be performed in 32 patients: 26 (81.3%) patients reached the response to treatment criteria (negative serology 6 months after treatment or when by enzyme-linked immunosorbent assay the optical density ratio of post-treatment to pre-treatment decreased to 0.6), and 11 (34.4%) patients fulfilled the cure criteria (negative serology 6 months after treatment). Strongyloides stercoralis serology is a useful diagnostic tool both in the diagnosis of probable strongyloidiasis and follow-up after treatment.

The effect of nanoliposomal formulations on Staphylococcus epidermidis biofilm

Objective: The aim of the present study was to assess the in vitro antimicrobial activities of nanoliposomal formulations loaded with vancomycin or/and rifampin against the biofilm formed by Staphylococcus epidermidis at 37 °C under aerobic condition.Materials and methods: Liposomal formulations were prepared by dehydration-rehydration (DRV) method and characterized for size, zeta potential and encapsulation efficacy. The ability of different formulations on eradication of bacterial biofilm was assessed through optical density ratio (ODr) and the results implicate higher survival rates of S. epidermidis on biofilm. Positive control was defined as an ODr = 1.0.Results: The zeta potential of anionic, cationic and PEGylated liposomes was −35 ± 2, 35 ± 1 and 27 ± 2 mV whereas the mean sizes of these liposomal formulations were 145 ± 4, 134 ± 1 and 142 ± 6 nm, respectively. Encapsulation efficacy of rifampin and vancomycin was more than 60% and about 25%, respectively. Cationic liposomal rifampin lowered the ODr to 0.61 and was the most effective formulations against S. epidermidis biofilm (p < 0.001). The antibiofilm activity of liposomal formulations was concentration- and time-dependent manner.Conclusion: The results of this study showed that rifampin-loaded liposomes were effective against bacterial biofilm.