Uncovering Differential Item Functioning effects using MIMIC and mediated MIMIC models.

The aim of this study was twofold: first, to examine the presence of bias across gender in a scholastic achievement test named the Academic Achievement Test (AAT) for the Science Track. Second, to understand the underlying mechanism that causes these bias effects by examining the effect of general cognitive ability as a mediator. The sample consisted of 1,300 Saudi high school students randomly selected from a larger pool of 173,133 participants to reduce the effects of excessive power. To examine both goals, the Multiple Indicators Multiple Causes (MIMIC) approach for detecting Differential Item Functioning (DIF) items was used. The results showed that 13 AAT items exhibited DIF effects for different gender groups. In most of these items, male participants were more likely to answer them correctly than their female counterparts. Next, the mediated MIMIC approach was applied to explore possible underlying mechanisms that explain these DIF effects. The results from this study showed that general cognitive ability (i.e., General Aptitude Test - GAT) seems to be a factor that could explain why an AAT item exhibits DIF across gender. It was found that GAT scores fully explain the DIF effect in two AAT items (full mediation). In most other cases, GAT helps account for only a proportion of the DIF effect (partial mediation). The results from this study will help experts improve the quality of their instruments by identifying DIF items and deciding how to revise them, considering the mediator's effect on participants' responses.

The Role of Response Times on the Measurement of Mental Ability.

The goal of the present study was to evaluate the roles of response times in the achievement of students in the following latent ability domains: (a) verbal, (b) math and spatial reasoning, (c) mental flexibility, and (d) scientific and mechanical reasoning. Participants were 869 students who took on the Multiple Mental Aptitude Scale. A mixture item response model was implemented to evaluate the roles of response times in performance by modeling ability and non-ability classes. Results after applying this model to the data across domains indicated the presence of several behaviors related to rapid responding which were covaried with low achievement likely representing unsuccessful guessing attempts.

The impact of carcinoma in situ in ureteral margins during radical cystectomy: A case-controlled study.

BACKGROUND AND OBJECTIVE: The presence of carcinoma in situ (Cis) in association with bladder cancer is associated with a poor prognosis. However, the prognosis associated with the presence of Cis in ureteral margins (CUM) during radical cystectomy has been poorly defined. To assess the prognosis associated with the presence of Cis in ureteral margins in patients with pM0 bladder cancer who have not undergone neoadjuvant chemotherapy. MATERIALS AND METHODS: A retrospective case-control study was conducted between 2001 and 2016 using data from one academic center in France. From 1,450 radical cystectomies, 122 patients (case) who had CUM were matched according to age, sex, pTNM stage and urinary diversion method with a population sample of 122 patients (controls) who did not have Cis in ureteral margins during radical cystectomy. The survival analysis was performed by Kaplan-Meier using a (95%) CI. Multivariate Cox regression analysis was used to test the effect of CUM on cancer-specific survival. Recurrence-free survival was defined as a recurrence of urothelial carcinoma in the upper urinary tract. RESULTS AND LIMITATIONS: The mean follow-up period was 55.43 ± 39.6 months. The rate of Cis in the bladder in the CUM cases group was evaluated at 11.47%. The median overall and specific survival was inferior in the CUM cases group estimated at 43.3 [35.33-56.93] months, 52.43 [42.16-68.93] months respectively compared to the control group with a significant difference (P= 0.001, P= 0.0039). The cumulative probability of urothelial recurrence-free survival was decreased in the case group compared with the control group (63.9% vs. 92.6%, P = 0.0001). Multivariate analysis shown that urothelial recurrence was associated with CUM [(P <0.001), (HR adjusted =11.31), (95% CI): (3.38-37.77)] and the macroscopic appearance of the ureter (thickened, dilated) [(P= 0.003), (HR adjusted =4.62), (95% CI): (3.31-8.84)]. CONCLUSION: CUM is a poor prognostic factor that impacts cancer-specific survival and Recurrence-free survival. The presence of CUM has been independently associated with a significant increase in the risk of urothelial recurrence, and a decrease in both overall and specific survival. This supports the use of frozen section analysis to complete radical cystectomy without CUM.

[Estimated impact of the current colorectal screening program in France]. / Estimation de l'impact du programme actuel de dépistage organisé du cancer colorectal.

BACKGROUND: Colorectal cancer is the third most common cancer and the second most deadly in France. A Cochrane meta-analysis has confirmed the benefits of colorectal cancer screening. A nationwide colorectal screening program was set up in France in 2009 for medium-risk, asymptomatic people aged 50 to 74 years. It has been based, since 2015, on the Fecal Immunochemical Test. The participation rate for 2016-2017 was 34%, which is lower than the European objectives. The objective of this study was to evaluate the impact of the program at the current participation rate and at rates of 45% and 65%. METHODS: The epidemiological impact of the program was estimated from the results of an individual simulation model adapted from the Microsimulation Screening Analysis Colon model, calibrated and transposed to the French context. An initial analysis was conducted to estimate the individual impact of screening and a second for the entire eligible population, at various participation rates. RESULTS: The test is associated with a lifetime reduction in the risk of colorectal cancer of 24% for men and 21% for women, and a reduction in the risk of death from colorectal cancer of 51% and 43% respectively. At the current level of participation, the program reduces incidence by 5% and mortality by 14% compared to no organized screening. The impact would be reduced by an additional 3% and 8% for participation rates of 45% and 65% respectively. Similarly, mortality would decrease by an additional 8% and 22%. CONCLUSION: These results confirm that in a population at medium risk for colorectal cancer, the organised programme is an effective strategy for reducing its incidence. They also confirm that the achievement of European objectives remains a key issue for improving the effectiveness of organized screening. An evolution of immunological test delivery modalities could help to achieve these participation objectives.

Susceptible vessel sign: identification of arterial occlusion and clinical implications in acute ischaemic stroke.

AIM: To determine the accuracy of the susceptible vessel sign (SVS) in the detection of arterial occlusion and its clinical implication in acute ischaemic stroke. MATERIALS AND METHODS: Consecutive ischaemic stroke patients who underwent magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) within 24 hours of symptom onset or time last-seen-well were included. Two independent neuroradiologists reviewed the SWI for evidence of the SVS. Admission stroke severity was determined by the National Institute of Health Stroke Scale (NIHSS) scores, and poor clinical outcome was defined by a 3-months modified Rankin scale (mRS) score >2. RESULTS: The SVS was identified in 26 (12%) of 213 patients with substantial inter-reviewer agreement. The SVS had 99% specificity, 88% negative predictive value (NPV), 51% sensitivity, and 92% positive predictive value (PPV) for detection of acute arterial occlusions. In consecutive stroke patients, the presence of SVS was associated with higher admission NIHSS scores (median 9 versus 3, p<0.001), arterial occlusion (92% versus 12%, p<0.001), larger infarct volume (162±180 ml versus 25±48 ml, p=0.001), and higher rate of poor clinical outcome at 3-months follow-up (58% versus 25%, p=0.001). In the subset of patients with acute arterial occlusion (n=47), the SVS was associated with higher admission NIHSS scores (median of 10 versus 3, p=0.038) and larger infarct volumes (173±184 ml versus 76±112 ml, p=0.034). CONCLUSIONS: The SVS is a highly specific sign of occlusive arterial thrombus, and is associated with larger infarct volume and more severe presentation in a series of consecutive stroke patients, as well as in the subgroup of patients with acute arterial occlusion.

Acute Ischemic Stroke Infarct Topology: Association with Lesion Volume and Severity of Symptoms at Admission and Discharge.

BACKGROUND AND PURPOSE: Acute stroke presentation and outcome depend on both ischemic infarct volume and location. We aimed to determine the association between acute ischemic infarct topology and lesion volume and stroke severity at presentation and discharge. MATERIALS AND METHODS: Patients with acute ischemic stroke who underwent MR imaging within 24 hours of symptom onset or last seen well were included. Infarcts were segmented and coregistered on the Montreal Neurological Institute-152 brain map. Voxel-based analyses were performed to determine the distribution of infarct lesions associated with larger volumes, higher NIHSS scores at admission and discharge, and greater NIHSS/volume ratios. RESULTS: A total of 238 patients were included. Ischemic infarcts involving the bilateral lentiform nuclei, insular ribbons, middle corona radiata, and right precentral gyrus were associated with larger infarct volumes (average, 76.7 ± 125.6 mL versus 16.4 ± 24.0 mL, P < .001) and higher admission NIHSS scores. Meanwhile, brain stem and thalami infarctions were associated with higher admission NIHSS/volume ratios. The discharge NIHSS scores were available in 218 patients, in whom voxel-based analysis demonstrated that ischemic infarcts of the bilateral posterior insular ribbons, middle corona radiata, and right precentral gyrus were associated with more severe symptoms at discharge, whereas ischemic lesions of the brain stem, bilateral thalami, and, to a lesser extent, the middle corona radiata were associated with higher ratios of discharge NIHSS score/infarct volume. CONCLUSIONS: Acute ischemic infarcts of the insulae, lentiform nuclei, and middle corona radiata tend to have larger volumes, more severe presentations, and worse outcomes, whereas brain stem and thalamic infarcts have greater symptom severity relative to smaller lesion volumes.

[Prevalence of overweight and obesity in schoolchildren in Tebessa (eastern Algeria) between 1995 and 2007]. / Prevalence du surpoids et de l'obésité chez des enfants scolarisés a Tébessa (est algérien) entre 1995 et 2007.

This study assessed the prevalence of overweight and obesity among public-school children aged 4 to 13 years in Tebessa, eastern Algeria over 10/12 years. Weight and height measurements of 21,618 schoolchildren were obtained from their health cards for 1995 to 2007 (49.4% girls and 50.6% boys). The prevalence of overweight and obesity in 2005/2007 was 8.49%, down from 17.39% in 1995/1998. Overweight decreased from 12.55% to 6.38% (P = 0.0001) and obesity from 4.48% to 1.80% (P = 0.0001) over the same time period. Children aged 10 to 13 years were the only ones who showed changes during this period. More girls were obese than boys (3.20% versus 2.82%, P = 0.033), while more boys were overweight (8.73% versus 7.94%, P = 0.034). While the rates of overweight and obesity have decreased over 10/12 years, the rates still suggest the need for epidemiological surveillance and the development of a health-oriented strategy for prevention of childhood obesity.

Prevalence of overweight and obesity in school children in Tebessa [eastern Algeria] between 1995 and 2007

This study assessed the prevalence of overweight and obesity among public-school children aged 4 to 13 years in Tebessa, eastern Algeria over 10/12 years. Weight and height measurements of 21 618 schoolchildren were obtained from their health cards for 1995 to 2007 [49.4% girls and 50.6% boys]. The prevalence of overweight and obesity in 2005/2007 was 8.49%, down from 17.39% in 1995/1998. Overweight decreased from 12.55% to 6.38% [P= 0.0001] and obesity from 4.48% to 1.80% [P= 0.0001] over the same time period. Children aged 10 to 13 years were the only ones who showed changes during this period. More girls were obese than boys [3.20% versus 2.82%, P= 0.033], while more boys were overweight [8.73% versus 7.94%, P= 0.034]. While the rates of overweight and obesity have decreased over 10/12 years, the rates still suggest the need for epidemiological surveillance and the development of a health-oriented strategy for prevention of childhood obesity

Castration of dromedary camel through prescrotal midline incision.

A total of 165 camels of different ages were castrated through a small, prescrotal midline incision between January, 2010 and December, 2011. The incision was closed with one interrupted, horizontal mattress suture using USP-2 chromic catgut. In 14/165 animals (8.5%) postoperative infection (sepsis) developed, which healed in two to three weeks after open wound management. The remaining 151 animals had an uneventful recovery, but a slight edematous swelling of the scrotum was observed in 8 of the 151 animals (5.3%), which was self-limiting and of no significance. No primary or secondary postoperative bleeding was noticed in any of the animals. It was concluded that this technique was less time consuming with negligible postoperative care and complications when performed under standard surgical principles.

[Prevalence of overweight and obesity in schoolchildren in Tebessa (Algeria) between 1998 and 2005]. / Prévalence du surpoids et de l'obésité chez les enfants scolarisés a Tébessa (Algérie) entre 1998 et 2005.

We studied the prevalence of obesity and overweight in schoolchildren aged 5-8 years in Tebessa, Algeria between 1998 and 2005. All schoolchildren in 5 primary schools (n = 3396) were included. Age, sex, height and weight were recorded. For classification of obesity and overweight the International Obesity Task Force definitions was used. The prevalence of obesity and overweight for the total sample was 6.36% and fell from 7.44% in 1998 to 5.81% in 2005. The prevalence of obesity was higher in girls than boys (1.58% vs 1.26%) (P = 0.430) while the prevalence of overweight was higher in boys than girls (5.60% vs 4.18%) (P = 0.057).

Prevalence of overweight and obesity in schoolchildren in Tebessa [Algeria] between 1998 and 2005

We studied the prevalence of obesity and overweight in schoolchildren aged 5-8 years in Tebessa, Algeria between 1998 and 2005. All schoolchildren in 5 primary schools [n = 3396] were included. Age, sex, height and weight were recorded. For classification of obesity and overweight the International Obesity Task Force definitions was used. The prevalence of obesity and overweight for the total sample was 6.36% and fell from 7.44% in 1998 to 5.81% in 2005. The prevalence of obesity was higher in girls than boys [1.58% vs 1.26%] [P =0.430] while the prevalence of overweight was higher in boys than girls [5.60% vs 4.18%] [P = 0.057]

Regulatory T-cell immunity and its relevance to atherosclerosis.

Atherosclerosis is a chronic inflammatory disease of the arterial wall where both innate and adaptive immune responses contribute to disease initiation and progression. Recent studies from several groups suggest that subtypes of T cells, called regulatory T cells, previously shown to maintain immunological tolerance, inhibit the development and progression of atherosclerosis. Here, we review the current knowledge on the regulatory T-cell response and the major cytokines involved in its modulation in the context of atherosclerosis.

Comparison of plasma uric acid levels in five varieties of the domestic turkey, Meleagris gallopavo.

Plasma uric acid (PUA) is a consensus physiological biomarker for many phenotypes in vertebrates because it is a reliable indicator for processes such as oxidative stress and tubular function. In birds, it is considered a major antioxidant and is also the primary endproduct of nitrogen metabolism. Despite this importance, knowledge of baseline levels of PUA in physiologically normal birds, including the turkey, Meleagris gallopavo, is limited. Here, we compared PUA levels in a total of 106 apparently normal male and female birds at 8 and 32 wk of age from 5 strains of the domestic turkey, including Bourbon Red, Narragansett, Blue Slate, Royal Palm, and Spanish Black. Though differences in PUA were not significant at 8 and 32 wk of age, BW, variety, and sex effects were highly significant. When adjusted for BW, female birds had, on average, a higher PUA per kilogram of BW than male birds. When adjusted for both sex and BW, Royal Palm birds had the lowest average PUA, and Blue Slate had the highest PUA. Results of these investigations represent the first comparative analysis of PUA in physiologically normal turkey varieties. They suggest that differences in basal plasma levels of uric acid in physiologically normal turkeys are influenced by sex, weight, and genetic background but may be independent of age.

Microarray profiling of human white adipose tissue after exogenous leptin injection.

BACKGROUND: Leptin is a secreted adipocyte hormone that plays a key role in the regulation of body weight homeostasis. The leptin effect on human white adipose tissue (WAT) is still debated. OBJECTIVE: The aim of this study was to assess whether the administration of polyethylene glycol-leptin (PEG-OB) in a single supraphysiological dose has transcriptional effects on genes of WAT and to identify its target genes and functional pathways in WAT. MATERIALS AND METHODS: Blood samples and WAT biopsies were obtained from 10 healthy nonobese men before treatment and 72 h after the PEG-OB injection, leading to an approximate 809-fold increase in circulating leptin. The WAT gene expression profile before and after the PEG-OB injection was compared using pangenomic microarrays. Functional gene annotations based on the gene ontology of the PEG-OB regulated genes were performed using both an 'in house' automated procedure and GenMAPP (Gene Microarray Pathway Profiler), designed for viewing and analyzing gene expression data in the context of biological pathways. RESULTS: Statistical analysis of microarray data revealed that PEG-OB had a major down-regulated effect on WAT gene expression, as we obtained 1,822 and 100 down- and up-regulated genes, respectively. Microarray data were validated using reverse transcription quantitative PCR. Functional gene annotations of PEG-OB regulated genes revealed that the functional class related to immunity and inflammation was among the most mobilized PEG-OB pathway in WAT. These genes are mainly expressed in the cell of the stroma vascular fraction in comparison with adipocytes. CONCLUSION: Our observations support the hypothesis that leptin could act on WAT, particularly on genes related to inflammation and immunity, which may suggest a novel leptin target pathway in human WAT.

[Physicochemical quality of drinking water in Southern Algeria: study of excess mineral salts]. / Qualité physico-chimique des eaux de boisson du Sud algérien: étude de l'excès en sels minéraux.

The aim of this study was to determine the physicochemical composition of water intended for human consumption in several regions of Southern Algeria. Excess minerals in drinking water, including magnesium, calcium, sulfates and fluorides play a fundamental role in the prevention of urinary calculi, which are formed mainly from calcium oxalate. The ever-increasingly prevalence of this disorder and its recurrence make it a real public health problem in Algeria. The most elementary preventive treatment, recommended to all subjects with lithiasis, is to drink 2 to 3 L water distributed throughout the (24-hour) day. This study began by conducting a physicochemical analysis of the principal components of water from several sources. We will subsequently test it to examine the effects of its mineral salts on the crystallization kinetics of the principal component of calculi (calcium oxalate). The results indicate that 77.5 % of the samples had magnesium concentrations ([Mg 2+] > 50 mg/L), 95 % were sulfated, with sulfate ion concentrations exceeding the standard recommended by WHO ([SO4 2-] > 250 mg/L). Moreover, 57.5 % had excess fluoride levels, [F-] > 1.5 mg/L, and 65 % excessive calcium concentrations, with Ca 2+ > 150 mg/L.

[Factitious lithiasis: Case report from Western Algeria]. / Identification de lithiase factice: à propos d'un cas observé dans l'Ouest algérien.

A 19-year-old woman with recurrent lithiasis was admitted to the urology department for renal colic. Although radiologic examinations and laboratory tests were negative, the patient regularly brought into consultations small "stones", resembling gravel, that she said had been spontaneously expelled. These 42 samples were the object of a preliminary morphological analysis under a binocular magnifier to detect their particulate components. A non-metabolic origin was suspected from the organoleptic characteristics of their surfaces and sections. In view of the diversity of the materials of these apparently false calculi, methods of precise physical analysis were necessary to ascertain their exact origin and thereby confirm the diagnosis of factitious lithiasis. The use of two methods of physical analysis, infrared spectrophotometry and x-ray diffraction, enabled us to determine their exact chemical and mineralogical composition. The samples claimed to be of urinary origin actually consisted of exogenous products of various compositions. Some samples were made of pure calcite, others of mixed calcite and silicates. Moreover several samples of the patient's first morning urine showed no correlation between the nature of the crystalluria and the composition of these stones. These tests made it possible to direct the clinician towards useful complementary investigations. This strange case represents 0.1% of the urinary calculi analysed in Western Algeria.

Comparison of different techniques for detection of Gal-GalNAc, an early marker of colonic neoplasia.

The tumor marker, D-galactose-beta [1-3]-N-acetyl-D-galactosamine (Gal-GalNAc, also known as T-antigen) can be identified by a very simple galactose oxidase-Schiff's (GOS) reaction either on tissues or on rectal mucus samples from patients with colorectal neoplasms. Gal-GalNAc is expressed in the neoplastic mucosa as well as the remote non-neoplastic mucosa. It is, however, not expressed in colonic mucosa of normal subjects. We studied the expression of Gal-GalNAc by GOS reaction, lectin reactivity and immunocytochemistry in 10 normal, .45 precancerous [5 Crohn's disease, 15 ulcerative colitis (5 without dysplasia and 10 with dysplasia), 25 tubular adenomas], and 25 adenocarcinoma cases. Normal mucosa remote from tubular adenoma and adenocarcinoma was also studied. The GOS method was compared with reactivity of the lectin jacalin and immunostaining with antibody to T antigen (Anti-Tag Ab). GOS reaction was negative in all of the 10 normal specimens. Of the 5 Crohn's disease specimens, 2 were positive and 3 negative. In the 5 ulcerative colitis cases without dysplasia, positive reaction was seen in 2 cases and negative in 3. Of the 10 cases of ulcerative colitis with dysplasia, 5 showed positivity in dysplastic areas, and 3 of these were also positive in remote non dysplastic mucosa. Twenty of 25 tubular adenomas yielded a positive reaction in the adenoma, 14 of them showing positivity also in remote mucosa; 3 cases showed a positive reaction only in remote mucosa. Of the 25 adenocarcinomas, 21 showed a positive reaction in the adenocarcinoma as well as the remote mucosa. GOS reaction was intense in well differentiated adenocarcinoma and weak in poorly differentiated adenocarcinoma. Intense reaction was also seen in the intracellular mucus of some aberrant crypts and morphologically normal crypts remote from adenocarcinoma and tubular adenoma. GOS reaction showed an overall sensitivity of 75.7% and specificity of 100% for cancer and precancerous lesions. Jacalin reactivity was slightly more sensitive (84.3%) but less specific (80%) and Tag Ab reactivity even less sensitive (50%) but as specific (100%) for neoplastic and dysplastic mucosa. We conclude that the detection of the carbohydrate moiety Gal-GalNAc varies with the technique used. Compared to other techniques, GOS reaction is extremely simple and has a high degree of sensitivity and specificity. It can be used for detection of this tumor marker in remote non-neoplastic mucosa of patients with neoplasia or at risk of developing neoplasia. It, therefore, could be used as a cost effective screening test in rectal biopsy specimens of such patients.

Profile of portal hypertension in hepatosplenic schistosomiasis.

Intrasplenic pressure changes versus ova count in stool of schistosomal portal hypertension in cases of bilharzial hepatic fibrosis were studied before and after 40 mg/kg body weight praziquantel therapy. Praziquantel acts on the vascular level in which it decreases the portal hypertension caused by bilharziasis as detected by decreased size of portal and splenic veins diameter as well as a significant decrease of portal pressure by the decrease of intrasplenic pressure (P less than 0.05). On the other hand, praziquantel decrease bilharzial stool egg count after 3 months of therapy (P less than 0.05).

Some immuno-pathological aspects in bilharzial and amoebic dysentery.

Serum immunoglobulin, secretory IgA in stools and leucocyte migration inhibition test were done for 75 patients suffering from bilharzial and amoebic dysentery as well as 20 normal controls. Sigmoidoscopic examination with immunofluorescent staining of colonic biopsy was done in patients with bilharzial dysentery. Humoral immune response increased significantly as detected by significant increase in serum IgG and IgM. Secretory IgA decreased significantly in bilharzial cases leucocyte migration inhibition test decreased significantly as well as plasma cells secreting IgA. This change in systemic and local immune response may predispose to infection or occur secondary to the disease.