The effect of explicit cultural bias on lateral preferences in Tunisia

Hand, eye and foot preferences in Tunisia were examined in relation to age, gender and geographic location. We analyzed 1291 questionnaires from 653 men and 638 women, aged 8 to 74 years. Despite the cultural pressure against the use of the left hand for food-related activities, the overall frequency of left-hand writers (10.9%) was comparable to that found in the Western world. The frequency of left-hand writers was higher for subjects with one left-handed parent, and even higher for subjects with two left-handed parents than for subjects whose parents were right handed. The frequency of left-hand writers dropped to 5.9% in the older age-group; it was found to be higher in Tunis, the largest and most Occidental city, than in other cities, while left-hand eating was lower in the South than in the Center or in the North. The frequency of left-footers also dropped in the older age groups and was higher in Tunis than in other cities. Eye preference, consistency of preferred-hand use, crossed hand-eye laterality, crossed hand-foot laterality and gender-related differences in lateral preferences were all comparable to Western results. These data suggest that lateral preferences are partly influenced by a genetic factor, but that handedness (and to a lesser degree footedness) emerges from the intricate interaction of several factors including genetic and cultural influences.     

Health risks of electromagnetic fields. Part III: Risk analysis

The management of potential health risks from electromagnetic (EM) fields presents both scientific and nonscientific challenges. When the scientific evidence is ambiguous, as is the case with EM fields, expert judgment of this evidence becomes particularly important. This article provides biomedical researchers with a comprehensive assessment of the status of EM health risk based on our two previous articles [Parts I and II, Critical Reviews in Biomedical Engineering, Volume 31, Issue 3]. Ambiguous evidence also necessitates rigorous public debate. This article also discusses effective risk communication approaches that play a key role in the EM risk issue. Because of uncertainty about health risks associated with EMF exposure, the public is more likely to experience difficulty in evaluating the available information and rely more on perceptions than facts when drawing conclusions. Even the most effective risk communication approaches are not likely to clarify all of the subtleties surrounding EM fields as a population health issue. Thus it is essential that all stakeholders involved in this issue participate in developing consensus solutions.     

Health risks of electromagnetic fields. Part II: Evaluation and assessment of radio frequency radiation

The increasing use of different radio frequency (RF)-emitting devices in residential and occupational settings has raised concerns about possible health effects of RF energy emitted by such devices. The debate about the potential risks associated with RF fields will persist with the prevalent network-connected wireless products and services targeting the marketplace for all kinds of consumer use. The aim of this article is to provide biomedical researchers with a review and critical evaluation of the current literature on acute and long-term health risks associated with RF radiation (RFR). Issues examined include safety standards for RFR; dosimetry and measurement surveys; and toxicological, epidemiological, and clinical studies of health outcomes that may be associated with RFR. Overall, the existing evidence for a causal relationship between RFR and adverse health effects is limited. Additional research is needed to clarify possible associations between RFR and biological effects noted in some studies. Particular attention should be directed toward long-term, low-level exposure to RFR.     

Lack of nephrotoxicity following 15-day therapy with high doses of colistin in rats.

BACKGROUND: Recent studies suggest that the incidence and severity of systemic toxicity due to colistin administration appear to be overstated. The objective of this study was to investigate colistin-induced nephrotoxicity in Wistar rats. MATERIAL/METHODS: Eighteen adult Wistar rats were divided into three groups: group I (controls, vehicle, n=6) rats were injected intramuscularly (i.m.) with physiological sodium chloride solution and groups II and III (colistin, n=6 each) rats were treated with colistin at a dose of 150,000 or 300,000 IU/kg body weight per day i.m, respectively. The drug injections were applied for 15 days. Twelve hours after the last injection the rats were sacrificed. The kidneys were quickly removed and blood samples were collected. Microscopic examination of the kidneys and measurements of serum creatinine and blood urea nitrogen concentrations were performed. RESULTS: The mean urea nitrogen concentrations were 5.95+/-0.58, 5.75+/-0.61, and 5.77+/-0.87 mmol/l and the mean serum creatinine concentrations were 45.5+/-1.87, 43+/-1.79, and 44+/-2.19 micromol/l in groups I, II, and III, respectively, without any statistical differences between the groups. Exposure to colistin did not cause any histological change in the kidney structure. CONCLUSIONS: These results suggest that colistin, when administered alone at usual doses, may not cause nephrotoxicity.     

About a short series of Swanson arthroplasty

The authors report a series of 12 patients who underwent digital arthroplasty using a swanson implant. Six patients had the sequellae of an injured hand, and the other six patients had rheumatoid arthritis. The majority of patients were men with an average age of 33 years. The patients were examined again about 4 years later on average. The lateral stability of the operated finger was considered to be satisfactory in 11 cases. The mean movement gain was 40 degrees. There was no sign of silicone particle synovitis, because it was fixed arthroplasty.     

The sacrified of sacrifice day

This prospective study was carried out in the plastic and reconstructive surgery department of Kassab's hospital in Tunis and the hospital of Monastir (Tunisa) during the sacrifice day (A?d el kebir). The study involved 50 patients. Our purpose was to identify the injuries of the hand occurring during this religions festival. The average age of patients was 39 years with sex ratio of 1.17. All socials and occupational sectors were affected. The lesions concern the dorsal face of non dominant hand (72%) with a peak in the frequency for the thumb (40%) and the index (37%). Extensor system of the radial finger on the non dominant hand was the main delicate element witch is most exposed during such festival. The thumb is being worthy of special mention, for it is the most serious lesions (amputation 10%) The lesions of flexor tendons are generally associated with nerve and vascular injury. 46% of patients had to undergo surgery.     

Cultural influences on the development of lateral preferences: a comparison between French and Tunisian children

We compared the development of laterality in two cultures that differ in pressure against left-handedness. Tunisian children, who are discouraged by their parents from using their left hand for all food-related activities, were compared to French children, who are allowed to use either the left or right hand. The subjects were 5, 7, and 9 years of age. To check the development of laterality, we tested hand preference (for writing and for performing 14 other manual activities), right-left performance difference, eye preference, and foot preference. The results showed that the frequency of left-handedness and left-eyedness was lower among Tunisian than among French children; this was particularly clear at age 5. Group difference almost disappeared in primary school children. Footedness did not differ between the two groups. Tunisian right-hand writers, although they probably included some children who might not have been right-handed without the cultural pressure, were not less consistent than French right-hand writers on the 14-item scale; they even showed a greater performance difference in favour of the right hand than the French on the pegboard task. These results may indicate that cultural pressure influences handedness at an early age, perhaps by leading towards right-handedness in children whose genetic background might otherwise have induced a chance-determined pattern of handedness.     

The effects of reading-writing direction on the asymmetry of space perception and directional tendencies: a comparison between French and Tunisian children

We compared the influence of reading and writing habits on the asymmetry of space perception and the directional tendencies of French and Tunisian right-handers, aged 5, 7, and 9 years. By comparing two groups of children who use the opposite direction for writing (from left to right for French, from right to left for Arabic), before and after being taught to read in school, we evaluated the impact of writing direction on these asymmetries. A bisection task, a circle-drawing task, and a dot-filling task were used to assess spatial asymmetries and directional tendencies. On the bisection task, a group difference emerged at 9 years, with the French children bisecting the line to the left of the true centre, and the Tunisian children showing no bias. On the circle-drawing task, there was a group difference from 7 years on, as the French children, but not the Tunisian children, used increasing counterclockwise movements. Finally, on the dot-filling task performed with the right hand, the French children filled in significantly more dots when going from left to right from 7 years on, whereas Tunisian children filled in more dots when going from right to left. These results show the impact of basic tendencies in younger children (ipsilateral bias in line bisection, clockwise direction in circle drawing, outward tendency for horizontal displacement in dot filling), as well as the impact of writing direction on spatial asymmetries after learning to read. The results are also discussed in reference to the differences between the two languages, the closeness of the French direction of writing to spontaneous neural-based tendencies, and the influence of learning French at age 8 for the Tunisian children.