Ecotoxicology of synthetic pyrethroids.

In this chapter we review the ecotoxicology of the synthetic pyrethroids (SPs). SPs are potent, broad-spectrum insecticides. Their effects on a wide range of nontarget species have been broadly studied, and there is an extensive database available to evaluate their effects. SPs are highly toxic to fish and aquatic invertebrates in the laboratory, but effects in the field are mitigated by rapid dissipation and degradation. Due to their highly lipophilic nature, SPs partition extensively into sediments. Recent studies have shown that toxicity in sediment can be predicted on the basis of equilibrium partitioning, and whilst other factors can influence this, organic carbon content is a key determining variable. At present for SPs, there is no clear evidence for adverse population-relevant effects with an underlying endocrine mode of action. SPs have been studied intensively in aquatic field studies, and their effects under field conditions are mitigated from those measured in the laboratory by their rapid dissipation and degradation. Studies with a range of test systems have shown consistent aquatic field endpoints across a variety of geographies and trophic states. SPs are also highly toxic to bees and other nontarget arthropods in the laboratory. These effects are mitigated in the field through repellency and dissipation of residues, and recovery from any adverse effects tends to be rapid.

Growth patterns in the growth-retarded premature infant.

Approximately 10% of all infants are born prematurely. A large proportion of these infants show evidence of postnatal growth impairment irrespective of whether birth weight was appropriate or small for gestational age. The timing and magnitude of catch-up growth is very variable, with the most immature infants showing markedly delayed catch up which is often incomplete. Long-term studies suggest that final stature may be affected significantly. Growth impairment in itself is of concern and there are suggestions that this group of infants should be eligible for growth hormone treatment. However, in addition, there is increasing evidence to suggest that there should be additional concerns in this group of infants, as abnormal early growth may influence disease susceptibility in adult life. This review assesses the patterns of postnatal growth and the possible later implications of early aberrant growth patterns in later life.

Evaluation of osseointegration of dental implants coated with collagen, chondroitin sulphate and BMP-4: an animal study.

Various studies have shown type I collagen (coll) to increase bone-implant contact (BIC) compared to uncoated implants. The aim of this animal study was to test whether the integration of chondroitin sulphate (CS) and the growth factor rhBMP-4 into a collagenous coating could further increase the measured BIC compared to collagen coated implants alone. The experimental implants had two recesses along the length axis. 120 implants with the surface modifications: coll, coll/CS, coll/CS/rhBMP-4 were inserted into the mandible of 20 minipigs. Six months after implantation, BIC was measured histomorphometrically on the surface and within the recesses. Due to the specific animal model and strict criteria in placement, 39.2 % of the implants were considered as failure and not included in the analysis. Of the successfully gained 73 implants, the highest percentage of BIC was obtained for coll/CS (40%), followed by coll (30%) and coll/CS/rhBMP-4 (27%), P=0.013. BIC within the recesses was highest for coll/CS (51%), followed by coll (43%) and coll/CS/rhBMP-4 (34%), P=0.025. The result suggests that the inclusion of CS slightly increases the BIC compared to collagen coated implants. The further inclusion of a low amount rhBMP-4 had a detrimental effect on bone formation compared to coll/CS, P<0.05.

An experimental study of the biomechanical stability of ultrasound-activated pinned (SonicWeld Rx+Resorb-X) and screwed fixed (Resorb-X) resorbable materials for osteosynthesis in the treatment of simulated craniosynostosis in sheep.

We compared a conventional resorbable screw osteosynthesis with a resorbable, ultrasound-activated pin osteosynthesis, and studied mechanical load capacity and operative handling. This new form of osteosynthesis aims to reduce operation times, and to avoid torque loads and screw fractures to achieve stability. A sheep craniotomy model simulated an operation for dysmorphia on an infant skull. Two rectangular craniotomies of equal size were created in 13 lamb skulls, and each refixed by different means: the first by mesh and 20 screws, and the second by mesh with 20 pins inserted with ultrasound activation. All osteosynthesis material consisted of resorbable amorphous poly-(d,l)-lactide (PDLLA) (Resorb-X, KLS Martin, Tuttlingen, Germany). The insertion time was recorded. The animals were killed at different times, and areas of the healing skull including the plates and pins or screws were removed and divided into sections, which were then tested. In total 74 pin-fixed and 77 screw-fixed samples were obtained. Bending and tensile tests were used to simulate different forms of loading. The time required for the insertion of pins was significantly shorter than for screws. The mechanical tests showed differences in the stability of the bond between the osteosynthesis plate and bone that depended on the osteosynthesis system and the length of time it was in the animal. The pin osteosynthesis gave a stable mechanical load capacity, which was significantly different from that of screw osteosynthesis. Advantages of ultrasound-assisted, resorbable, pin osteosynthesis, include optimum operative handling, reduced insertion time, avoidance of fractures of the fixation elements and higher three-dimensional load capacity.

An experimental in vivo analysis of the resorption to ultrasound activated pins (Sonic weld) and standard biodegradable screws (ResorbX) in sheep.

We compared the healing and reaction in the mandibles of 11 sheep of a conventional bioresorbable screw osteosynthesis with the newly developed ultrasound-activated pin osteosynthesis. The thermal stress caused by insertion of the ultrasound-aided pins leads to no cellular reaction around the pin. There is neither clinical nor histological evidence of any initial inflammation that could have been induced by the insertion. Adequate attachment of fibrous tissue to the pin head and the absence of any inflammation are important preconditions for the introduction of this new method of osteosynthesis into clinical practice. Further advantageous characteristics are easy intraoperative handling and a reduction in operating time, because cutting the thread is not required. There must be sufficient interlinkage of the polymer and the trabecular structures to ensure stability.

[Conventional tomographic investigations of the reconstructed middle ear in temporal bone specimen]. / Röntgentomografische Untersuchungen des rekonstruierten Mittelohres am Felsenbeinpräparat.

BACKGROUND: In modern reconstructive middle ear surgery imaging plays an essential role as a diagnostic tool, especially in pre-operative planning. Nowadays imaging of surgical results as a matter of quality control in post-operative follow-up becomes more important. MATERIAL AND METHODS: Conventional tomography was performed in 10 temporal bone specimen using the CommCat IS 2000-system in order to evaluate anatomical structures and inserted middle ear prostheses (PORP/TORP). This imaging technique has not been used in middle ear surgery beforehand. RESULTS: Using conventional tomography characterization of anatomical structures of the temporal bone as e. g. the semicircular canals appeared to be of superior quality to comparable conventional radiographic imaging. Concerning imaging quality (contrast; resolution) conventional tomography allowed similar findings like computed tomography (CT)-scans in some of the investigated specimen while showing inferior sharpness quality due to technical reasons. Further advantages of conventional tomography in contrast to CT were the requirement of just 2.5 % of the CT's irradiation exposure, lack of metallic artefacts caused by implanted prostheses and the feasibility of distance- and angle-measurement of inserted prostheses towards the tympanic membrane which coincided extensively with the temporal bone preparation. CONCLUSIONS: Conventional tomography enables detailed anatomical imaging of the temporal bone region which outperforms conventional radiographic imaging, requires less irradiation dose than CT and helps avoid problems like metallic artefacts. This technique enhances immediate quality-control and seems to be therefore a promising tool for postoperative evaluation after reconstructive middle ear surgery.

[Custom moldable hydroxyapatite collagen composite for repair of osseous defects]. / Frei modellierbare Hydroxylapatit-Kollagen-Komposite zur Sanierung ossärer Defekte.

AIM: In the following study we evaluated the biological response of a new freely moldable bone substitute in an animal model. MATERIAL AND METHODS: Critically sized defects were created surgically in the lower jaw of ten adult minipigs. The drill defects were filled with hydroxyapatite collagen paste. After observation periods of 1, 3, 6, 12, and 18 months the mandibles were harvested without wound healing defects for histological evaluation of resorption and bone ingrowth with a sawing and grinding technique. RESULTS: The result of the remodeling process was a complete degradation of hydroxyapatite collagen implants after 12-18 months with reorganization of vital trabeculae oriented in a mature pattern. CONCLUSION: The hydroxyapatite collagen cement works as an osteoconductor and shows signs of direct osseointegration and resorption.

[Preoperative determination of the position of mandibular canal for planning sagittal ramus osteotomy of the mandible]. / Präoperative Lagebestimmung des Canalis mandibulae vor sagittaler Ramusosteotomie des Unterkiefers.

BACKGROUND: In the literature the incidence of permanent nerve lesions ranges from 3 to 39%. Therefore, we think that it is necessary to discuss the procedure of individual risk assessment and management. Standard imaging techniques for the preoperative planning and preparation of a sagittal split osteotomy usually include a panoramic radiograph and lateral cephalometric radiograph. If an assessment of the transversal thickness of the lower jaw and cortical substance is required, or the position of the inferior alveolar nerve needs to be determined for preoperative planning, computed tomography of the viscerocranium has to be performed. By employing the conventional computed tomographic X-ray imaging system CommCAT, we are able to determine preoperatively both the transversal thickness of the lower jaw including the cortical substance and the diameter of the ascending ramus of the mandible at the proximal osteotomy site. PATIENTS AND METHOD: We examined prospectively the value of these additional investigations and compared them with the intraoperative findings in 29 patients. With these tomograms, the relation between the position of the inferior alveolar nerve and the vestibular cortical bone was metrically evaluated. In 17 of 58 jaw sides we detected the nerve at a distance from the outer cortical bone of 2 mm or less. The situation for the upper osteotomy was critical in eight cases where the thickness of the mandibular ramus was only 3 mm. RESULTS: By using of the conventional computed tomography system CommCAT, we have the preoperative opportunity to determine the transversal thickness of the mandibular ramus as well as the exact position of the inferior alveolar nerve and its distance from the cortical bone of the mandibular corpus. By predicting the nerve's position and its relation to the osteotomy site, we are able to individualize the operation procedure so that a high standard of safety can be achieved.

A randomised controlled trial comparing two methods of teaching medical students trauma and orthopaedics: traditional lectures versus the "donut round".

OBJECTIVE: To assess whether a new form of teaching, the 'donut round', is as good at imparting factual knowledge as interactive lectures in both the short-term and the long-term. DESIGN: Randomised controlled trial. SETTING: University of Oxford Medical School. PARTICIPANTS: 106 fifth year clinical medical students taught half of their A&E/trauma course by donut round and half by lecture. MAIN OUTCOME MEASURES: The results of multiple choice questions (MCQs) divided according to how the material was taught. Three MCQ papers were set: one at the end of a four-week course, one approximately 10 weeks later and a final exam approximately 17 months after the first. RESULTS: At the first MCQ, the average result for questions taught by donut round was 41.0 (out of 50) and for those taught by conventional lecture was 40.1. At 10 weeks these averages fell to 36.3 and 37.3 and at 17 months they were 38.7 and 38.1, respectively. None of these pairs were significantly different. Ratios were calculated for each candidate by dividing their donut round score by their lecture score. The average ratios for the first, second and third MCQ papers were: 1.029, 1.007 and 1.027, respectively, and were not significantly different. The individual ratios of all candidates in all three MCQs were plotted against their equivalent total mark. The calculated linear regression showed a statistically significant advantage of donut rounds over lectures in those candidates who scored a total mark less than 89 (n=260, p=0.02). CONCLUSIONS: Donut rounds are at least as good as lectures in imparting factual knowledge and may provide a selective advantage to weaker students.

[Gunshot injuries in the head-neck area--basic principles, diagnosis and management]. / Schussverletzungen im Kopf-Hals-Bereich--Grundlagen, Diagnostik und Versorgung.

Bullet wounds are a rare occurrence during times of peace. Recently, however, there has been a general increase in the number and severity of this type of trauma in our case load. First, the possible firearms and the individual types of ammunition will be discussed. Based on this background, the possible types of wounds are presented. Principally, one distinguishes ricocheting shots from grazing ones, and those leaving bullets lodged in the body from those with perforating wounds. The extent of tissue damage depends on internal lacerations, on the compression of the tissue and on the temporary cavitation along the projectile path. In contrast to other types of injuries, which are caused by a blow or impact to the face or skull, gunshot traumas are characterized by an irregular path, as well as, by localized destruction of bones with associated effects. In this connection, the severity of the bullet wound also depends upon the extent of involvement of the viscerocranium. As causes of gunshot wounds during times of peace, suicidal intent, the negligent handling of firearms and especially brutal crimes are those which come into consideration first and foremost. The diagnostic aspect of firearm wounds, beside anamnesis, comprises comprehensive X-ray diagnostics for a complete picture. From the therapeutic side, tetanus serum and antibiotics as a prophylactic are recommended initially. The operative treatment should take place depending on the injury with the removal of a possible projectile. Bullet wounds always require an interdisciplinary approach to treatment.

[Diagnostic and therapeutic problems in gunshot wounds]. / Diagnostische und therapeutische Probleme bei Schussverletzungen.

BACKGROUND: Bullet wounds are a rare occurrence during times of peace. Recently, however, there has been a general increase in the relative number and severity of this type of trauma. In times of peace, gunshot wounds may be mainly caused by suicide attempts, negligent handling of firearms and especially violent conflicts. Bullet wounds, in contrast to wounds caused by a blow or impact to the viscerocranium, are characterised by an irregular path, entry and exit wounds, as well as localised demolition of bones with the associated defects. PATIENTS: 30 patients with gunshot wounds were treated during the past 35 years. Basing on four case reports, problems of interdisciplinary treatment approach to gunshot wounds are discussed, as well as the diagnostic and therapeutic consequences. RESULTS AND CONCLUSIONS: The first case concerns a retained missile in the left fossa pterygopalatina. Intraoperative removal caused a rupture of the A. maxillaris. Preoperative angiography could have provided valuable information. In the second case, an injury caused by a shot from a blank cartridge pistol in the left facial area resulted in extensive wounds with several surgical revisions. The third case was a shot injury to the tongue with an unexpected wound and bleeding. The fourth case describes a child with a bullet in a hyperplastic adenoid tonsil. Primary careful treatment is of greatest significance for functional and cosmetic results due to extensive rupturing and wounds.

Comparison of visual-discrimination ability of brain-injured and non-brain-injured children of normal intelligence.

A set of 106 multiple-choice geometric designs were administered to 23 children diagnosed as minimally brain-damaged and 23 control children. All children were between the ages of 4 and 12 yr. and were matched for age and intelligence. Differences between the two groups suggest that, although rotation and reversal errors significantly discriminate the groups, factors which lead to distractions are more discriminative. The data suggest the possibility of an easily administered and objectively scored instrument which is relatively independent of motor development in children.