Role of wing color and seasonal changes in ambient temperature and solar irradiation on predicted flight efficiency of the Albatross.

Drag reduction of the wings of migrating birds is crucial to their flight efficiency. Wing color impacts absorption of solar irradiation which may affect drag but there is little known in this area. To this end, the drag reduction induced by the thermal effect of the wing color of migrating birds with unpowered flight modes is presented in this study. Considering this natural phenomenon in the albatross as an example of migrating birds, and applying an energy balance for this biological system, a thermal analysis is performed on the wings during the summer and winter to obtain different ranges of air density, viscosity, and wing surface temperature brought about from a range of ambient temperatures and climatic conditions seen in different seasons and to study their effects. The exact shape of the albatross wing is used and nine different wing colors are considered in order to gain a better understanding of the effect different colors' absorptivities make on the change in aerodynamic performances. The thermal effect is found to be more important during the summer than during the winter due to the higher values of solar irradiation and a maximum drag reduction of 7.8% is found in summer changing the wing color from light white to dark black. The obtained results show that albatrosses with darker colored wings are more efficient (constant lift to drag ratio and drag reduction) and have better endurance due to this drag reduction.

Thermal impact of migrating birds' wing color on their flight performance: Possibility of new generation of biologically inspired drones.

The thermal impact of the birds' color on their flight performance are investigated. In most of the large migrating birds, the top of their wings is black. Considering this natural phenomenon in the migrating birds, such as albatross, a thermal analysis of the boundary layer of their wings is performed during the year depending on the solar insulation. It is shown that the temperature difference between the bright and dark colored top wing surface is around 10°C. The dark color on the top of the wing increases the temperature of the boundary layer over the wing which consequently reduces the skin drag force over the wing. This reduction in the drag force can be considered as one of the effective factors for long endurance of these migrating birds. This research should lead to improved designs of the drones by applying the inspired colors which can help drones increase their endurance.

[Ileocecal ameboma: a case diagnosed by pathology and molecular biology]. / Amoebome iléocaecal: un cas diagnostique par l'anatomie pathologique et la biologie moléculaire.

Colonic ameboma is a rare benign inflammatory tumor due to the infection by Entamoeba histolytica and poses frequently the problem of colon cancer. We report a case of a 52 year-old patient who presented a cecal amoeboma revealed by a painful mass in the right iliac fossa. Radiologic and endoscopic examinations depicted a parietal thickening of the right colon and the cecum. A presumptive diagnosis of colon cancer was firstly discussed. Confirmation of ameboma was made on pathological examination, PCR and serology.

[The intestinal parasites in the food handlers of Tunis area: study of 8502 stool samples (1998-2008)]. / Les parasites intestinaux chez les manipulateurs de denrees alimentaires de la Region de Tunis: etude de 8502 prelevements de selles (1998-2008).

The food handlers control is one of the major measures of the National program against intestinal parasitoses in Tunisia. The collected data allow regular updates of the prevalence and profile of the involved parasitic species and note possible evolutions in time. From 1998 to 2008, 8502 stool samples of food handlers working in Tunis area were examined in the laboratory of Parasitology, Pasteur Institute of Tunis. The mean prevalence of intestinal parasites was 13.5% (1152 positive samples). The protozoa were the most detected parasites (93% of the species observed). Among the pathogenic or potentially pathogenic parasites, Dientamoeba fragilis (15.5%) and Giardia intestinalis (7.6%) were the most frequently encountered. Entamoeba (E.) histolytica/dispar was diagnosed in 41 subjects (a prevalence of 05%). Hymenolepis nana was the most frequent helminth (45% of the whole parasites). Therapeutic failures were noticed in 43.8% of infection by this cestode because of the lack of the appropriate antihelminthic. The identification using PCR of cysts and/or vegetative forms of E. histolytica/dispar revealed the exclusive presence of E. dispar.

[Cardiac biomarkers for diagnosis of myocardial infarction]. / Marqueurs biologiques de l'infarctus du myocarde.

Diagnosis of postoperative myocardial infarction is often difficult, based on tools with a low sensitivity (clinical symptoms, EKG), or with a low specifity (old biomarkers, echocardiographic abnormalities) or inadequate for clinical practice (scintigraphy). Since 1995, clinicians may use more cardiospecific markers (troponin) allowing to modify strategy for postoperative myocardial infarction diagnosis. The aim of this review is to resume such an attitude.

Molecular differentiation of Entamoeba histolytica and Entamoeba dispar from Tunisian food handlers with amoeba infection initially diagnosed by microscopy.

The purpose of the study was to obtain more reliable epidemiological data concerning Entamoeba (E.) histolytica infection in Tunisian food handlers using established molecular tools able to differentiate E. histolytica from E. dispar. From 2002 to 2005, 4,266 fresh stools specimens received in the setting of the National program of food handlers' control were analysed by optical microscopy. Twelve (2.8 per thousand) were positive for the presence of four nuclei cysts identified as E. histolytica/E. dispar. Extraction of DNA from the 12 samples, followed by specific amplifications of E. histolytica and E. dispar SSU rDNA, showed that 11 samples (92%) were positive for E. dispar and negative for E. histolytica. Sequencing analysis of 8 PCR products permitted to verify the results obtained with conventional PCR. The remaining sample was negative by PCR amplifying E. histolytica DNA or E. dispar DNA specifically, although it did not show any inhibition. It probably contains protozoan cysts genetically distinct from these two species but morphological similar. Estimation of relative proportions between E. histolytica and E. dispar in cyst carriers showed that all explored individuals harboured the non pathogenic E. dispar strains. This result highlights the need of use in this population of complementary tests that allow specific diagnosis and obviate unnecessary chemotherapy.

Accessory gene regulator (agr) typing of Staphylococcus aureus isolated from human infections.

Staphylococcus aureus is a major hospital and community acquired pathogen. A total of one hundred strains were investigated. They were collected from January 2004 to July 2006 in the laboratory of microbiology at Charles Nicolle University hospital of Tunis. The isolates were identified by conventional methods. Methicillin resistance was confirmed by amplification of mecA gene by PCR. The agr groups were identified by multiplex PCR. The agr groups were distributed as follows: 19 strains belonged to group I, 16 to group II and 65 to group III. Among methicillin resistant S. aureus (MRSA), 9 (16.4%) belonged to group 1, 8 (14.5%) to group II and 38 (69.1%) to group IlI. For methicillin susceptible S. aureus (MSSA), only 10 strains (22.2%) belonged to group I, 8 (17.8%) to group II and 27 (60%) to group III. A preferential link was observed between agr group I and invasive infections (P=0.003) especially bacteremia (P=10(-4). Besides, agr groups II and III were closely related with non invasive infections (P=0.003). No association was found between other types of infections and agr groups. Likewise, no correlation was observed between agr groups, age or sex of patients and type of infections.

Prevalence of agr specificity groups among methicilin resistant Staphylococcus aureus circulating at Charles Nicolle hospital of Tunis.

Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen with many clinical aspects. In S. aureus, the accessory gene regulator (agr) globally controls the production of virulence factors. There are four agr groups. Our study was done to define the agr specificity of MRSA circulating at Charles Nicolle hospital and to investigate a possible relationship between agr groups and human disease types. From January 2004 to June 2005, a total of 57 MRSA isolated from individual hospitalized patients were collected, representing 12% of the total S. aureus isolates. The isolates were identified by conventional methods. Methicillin resistance was detected by oxacillin and cefoxitin disks and confirmed by the amplification of mecA gene by PCR. The agr groups were identified by multiplex PCR. All the strains were recovered from different wards: medicine (57.8%) especially from dermatology (56.2%), surgery (28%) and pediatrics (7%). Cutaneous pus (36.84%) and blood culture (35.08%) represented the main specimens. The agr groups were distributed as follow nine (15.7%) belonged to group I, two (3.5%) belonged to group II and 23 (40.3%) belonged to group III. For 23 strains, the agr group was not identified. A relationship between agr group and type of disease was observed: agr group III strains were associated with non invasive infections (P=0.02) and agr group I strains with invasive infections especially bacteremia (P=0.002).

Cardiac troponin I is reliable with immediate but not medium-term cardiac complications after abdominal aortic repair.

BACKGROUND: The diagnosis of cardiac complications is particularly challenging in the postoperative course of non-cardiac surgery. Follow-up of patients suggests that silent or symptomatic postoperative myocardial infarction have similar short-term outcomes. Cardiac troponin I (cTnI) has been reported as being a sensitive and specific marker of these complications. METHODS: We conducted a prospective study to determine the cut-off values of cTnI which may predict cardiac complications, i: in the postoperative period until discharge, and ii: during a 1-year period after aortic surgery. Three hundred and twenty-nine consecutive patients undergoing infrarenal aortic surgery were included over a 2-year period in a single center. cTnI was measured at recovery and on the 1st, 2nd and 3rd postoperative days. The presence or absence of cardiac complications was classified by reviewers who had no knowledge of cTnI. For evaluation of the ideal discrimination value of cTnI between the complicated and uncomplicated patient groups, we calculated receiver-operator characteristics for the mean values of the peak of cTnI. RESULTS: Thirteen patients (4%) developed 19 postoperative cardiac complications. Thirteen patients (4%) died in the postoperative period. Nine patients (3%) developed 10 cardiac complications during the 1-year follow-up in 316 patients. In 280 patients, cTnI was below 0.5 ng/ml, in 22 patients between 0.5 and 1.5 ng/ml and the 27 remaining patients had a cTnI higher than 1.5 ng/ml. The area under the curve for postoperative cardiac complications was 0.84 (SD=0.21). A limit value of 0.54 ng/ml yielded a sensitivity of 75% and a specificity of 89%. The area under the curve for late cardiac complications was 0.45 (SD= 0.13). CONCLUSION: A cTnI level greater than 0.54 ng/ml appears to be correlated with the occurrence of cardiac complications in the period until discharge, but no value of cTnI is predictive of late cardiac complications occurring in the 1st year after aortic surgery.

Cardiac troponin I cutoff values to predict postoperative cardiac complications after circulatory arrest and profound hypothermia.

OBJECTIVE: Cardiac failure and myocardial infarction are complications of thoracic aorta, thoracoabdominal aorta, or aortic arch surgery, especially when surgery is performed using profound hypothermia and circulatory arrest (PHCA). Moreover, the diagnosis of non-Q-wave postoperative myocardial infarction (PMI) is challenging because there is no gold standard. The aims of this study were to determine values for cardiac troponin I (cTnl) in patients undergoing aortic arch or thoracoabdominal aortic surgery with PHCA who were free of cardiac complications in the postoperative period, and to test the validity of cutoff values of cTnl to predict postoperative cardiac complications in such patients. DESIGN: Prospective, nonrandomized study. SETTING: Single university hospital; Departments of Anesthesiology, Biochemistry and Vascular Surgery. PARTICIPANTS: Fifty-two consecutive patients were studied over a 2-year period. None was excluded, even patients who underwent emergency surgery. INTERVENTIONS: Patients undergoing aortic arch or thoracoabdominal aortic surgery with PHCA were studied. Thirty patients undergoing coronary artery bypass grafting (CABG) in the same period constituted a control group. MEASUREMENTS AND MAIN RESULTS: The cTnl concentrations were determined using an immunoenzymofluorometric assay on a Stratus analyzer (Dade, Massy, France) on blood samples obtained at recovery and on day 1 (D1) and D2. Seventeen patients developed a cardiac complication, which was lethal in 10 patients. In patients without cardiac complication, the peak level for cTnl was observed on D1. Cutoff values of cTnl were identical in both the CABG control group (11 .6 microg/mL) and the sternotomy group (12.2 microg/mL), but were significantly greater (20.5 microg/mL) in patients with a thoracotomy approach. Sensitivity and specificity of these cutoff values were high in both groups (control group, sensitivity = 100%, specificity = 100%; sternotomy group, sensitivity = 78%, specificity = 100%; thoracotomy group, sensitivity = 100%, specificity = 94%). CONCLUSION: In patients who underwent surgery using PHCA for aortic arch or descending aorta repair, myocardial damage related to cardiac arrest, vents or fibrillation explains the increased cutoff value (12.2 microg/mL). This value is similar to patients undergoing CABG surgery through a sternotomy approach with cardioplegia administration. In contrast, and probably related to the absence of cardioplegia, patients undergoing surgery through a left thoracotomy approach had a greater cutoff value (20.5 microg/mL). Values of cTnl greater than these respective cutoff values were closely related to cardiac complications during the postoperative period.

Does the enhancement of cholinergic neurotransmission influence brain glucose kinetics and clinical symptomatology in progressive supranuclear palsy?

Cholinergic systems are markedly affected both in cortical and subcortical cerebral areas of patients with progressive supranuclear palsy (PSP). To determine whether it is possible to modify the clinical picture of PSP through the enhancement of brain cholinergic neurotransmission, we studied the effects of physostigmine, an anticholinesterase reference drug, on symptoms and brain glucose metabolism using [18F]fluorodeoxyglucose (FDG) and PET. Patients were evaluated blind in a randomized order with both placebo and physostigmine infusions after an individual determination of maximal tolerated dose. Under steady-state physostigmine infusions, although glucose consumption was not significantly modified, the entry of glucose from blood to brain was regionally increased from 8 to 32% of placebo values suggesting an increase in cerebral blood flow (CBF) or an increase in the activity of brain glucose transporter. Following physostigmine administration in the same patients: the errors in antisaccades during ocular movement testing were significantly reduced, a significant reduction in errors or performance was found in four out of seven neuropsychological tests, and motor disability was not significantly altered. Although the precise pathophysiology of these physostigmine-induced effects needs further investigations, our study suggests that part of the clinical symptomatology in PSP could be relieved by the enhancement of brain cholinergic neurotransmission.

On some glycosidases (beta-D-mannosidase, alpha-L-fucosidase, N-acetyl-beta-D-glucosaminidase) of human seminal plasma.

The glycosidase activities (beta-D-mannosidase, alpha-L-fucosidase and N-acetyl-beta-D-glucosaminidase) have been compared in whole and split ejaculate samples from men whose couple suffers from infertility. The site of secretion of enzymatic activities is either prostatic or epididymal. The three enzymatic activities have possibly different origin and should constitute new biochemical markers of male genital tract.