Optimum design of family structure and allocation of resources in association mapping with lines from multiple crosses.

Family mapping is based on multiple segregating families and is becoming increasingly popular because of its advantages over population mapping. Athough much progress has been made recently, the optimum design and allocation of resources for family mapping remains unclear. Here, we addressed these issues using a simulation study, resample model averaging and cross-validation approaches. Our results show that in family mapping, the predictive power and the accuracy of quatitative trait loci (QTL) detection depend greatly on the population size and phenotyping intensity. With small population sizes or few test environments, QTL results become unreliable and are hampered by a large bias in the estimation of the proportion of genotypic variance explained by the detected QTL. In addition, we observed that even though good results can be achieved with low marker densities, no plateau is reached with our full marker complement. This suggests that higher quality results could be achieved with greater marker densities or sequence data, which will be available in the near future for many species.

Kinematic effects of inertia and friction added by a robotic knee exoskeleton after prolonged walking.

The capabilities of robotic gait assistive devices are ever increasing; however, their adoption outside of the lab is still limited. A critical barrier for the functionality of these devices are the still unknown mechanical properties of the human leg during dynamic conditions such as walking. We built a robotic knee exoskeleton to address this problem. Here, we present the effects of our device on the walking pattern of four subjects. We assessed the effects after a short period of acclimation as well as after a 1.5h walking protocol. We found that the knee exoskeleton decreased (towards extension) the peak hip extension and peak knee flexion of the leg with the exoskeleton, while minimally affecting the non-exoskeleton leg. Comparatively smaller changes occurred after prolonged walking. These results suggest that walking patterns attained after a few minutes of acclimation with a knee exoskeleton are stable for at least a couple of hours.

Autogenous auricular cartilage graft for temporomandibular joint repair. A comparison of technique with and without temporary silastic implantation.

Four Macaca fascicularis monkeys underwent bilateral temporomandibular joint surgery including disc removal, condyle recontouring and disc replacement using autogenous auricular cartilage grafts. One side was treated with the cartilage graft alone while the other side was treated with a cartilage graft combined with a temporarily implanted 0.02 inch dacron-reinforced silastic sheet. The silastic sheeting was removed at twelve weeks after the initial surgery. The monkeys were sacrificed at fourteen, twenty-four, thirty-six and fifty-two weeks after the initial disc removal and cartilage grafting. The joints treated with cartilage grafts alone showed significant fibrous connective tissue adhesions which had formed between the inferior surface of the graft and the articulating surface of the condyle. In the joints treated with a cartilage graft and silastic sheeting a joint space was clearly maintained between the cartilage graft and condylar surface without the formation of fibrous connective tissue adhesions. It appears that temporary implantation of a thin silastic sheet combined with autogenous cartilage grafting may prevent the formation of fibrous connective tissue adhesions within the joint.

Stress shielding effect of rigid internal fixation plates on mandibular bone grafts. A photon absorption densitometry and quantitative computerized tomographic evaluation.

The use of rigid internal fixation reconstruction plates in combination with bone grafts provides many advantages in mandibular reconstruction. These advantages include ease of adaptability at the time of surgery as well as immediate postoperative function for the patient. Disadvantages may include a "stress shielding" or disuse osteoporosis effect on the underlying bone graft as a result of the rigidity of the reconstruction plate. This study evaluated the stress shielding effects on bone grafts in primate mandibles. Bilateral bone grafts stabilized with rigid fixation plates were performed in 4 Macaca fascicularis monkeys. Three months after the bone grafting procedure one plate was removed from each monkey. The monkeys were then killed 1, 4, 6 and 8 months after plate removal. Photon absorption densitometry and computerized tomography were used to evaluate stress shielding. The results of this study indicate that the stress shielding effect occurs if the plate is not removed from the area of bone grafting postoperatively.

Histomorphometric evaluation of stress shielding in mandibular continuity defects treated with rigid fixation plates and bone grafts.

Histomorphometric techniques were used to evaluate the stress shielding effect in bilateral bone grafts in 4 Macaca fascicularis monkeys. Bilateral continuity defects were created and grafted by replacing the resected portion of the mandible and iliac crest bone into the defect area. Both sides were plated with rigid internal fixation plates. Three months after bone grafting, the plate was removed from one side while the other plate was left in place. The animals were sacrificed at 1, 4, 6, and 8 months after plate removal and the grafted areas removed for histomorphometric analysis. This study documents decreased bone volume as well as smaller interlabel width on the plated side, suggesting a stress shielding effect as a result of the rigid internal fixation plate.

A comparison of amnesia in outpatients sedated with midazolam or diazepam alone or in combination with fentanyl during oral surgery.

Midazolam is a new, water-soluble benzodiazepine that has been reported to produce a greater degree of amnesia than does diazepam. This study compares the amnesia produced in patients sedated with midazolam or diazepam or in combination with fentanyl during oral surgery. Twenty-four hours after surgery, each patient answered a questionnaire designed to assess his or her recall of events during and after surgery. Patients who received midazolam alone recalled significantly less than did patients in either diazepam group. The addition of fentanyl to midazolam did not produce any significant difference in recall.

Recovery following sedation with midazolam or diazepam alone or in combination with fentanyl for outpatient surgery.

Midazolam is a new water-soluble benzodiazepine with a much shorter pharmacologic half-life than diazepam. Despite this shorter pharmacologic half-life, several reports indicate that patients do not recover more rapidly after sedation with midazolam than with diazepam. The purpose of this study was to compare recovery of patients sedated with either midazolam or diazepam alone or in combination with fentanyl using the digit symbol substitution test (DSST) and Trieger test. Patients were randomly divided into treatment groups and recovery tests were administered to the patients prior to sedation and at 60, 120, and 180 minutes after achieving a standardized sedative endpoint. Patients who received midazolam alone had significantly fewer numbers of correct reponses on the DSST than patients who received midazolam plus fentanyl or diazepam with or without fentanyl. When midazolam was combined with fentanyl there was no significant difference between results obtained on the DSST when compared with either diazepam group. Comparisons between all groups using dots missed or millimeter deviation on the Trieger test showed no statistical difference between any groups. These data indicate that midazolam as a single IV agent has a slightly prolonged recovery phase compared to diazepam. The addition of fentanyl to the sedation regimen allows reduction in the midazolam dose resulting in a recovery time comparable to that of diazepam.

Complex orthodontic problems: the orthognathic patient with temporomandibular disorders.

The diagnosis and treatment of temporomandibular disorders (TMD) remain controversial despite considerable research and publication in this area. The relationship of these problems to dental and skeletal malocclusion is equally debatable. Recent studies suggest that although malocclusion may have a role, it is a small one. Accordingly, treatment of TMD with occlusion-altering therapy, such as orthodontics and orthognathic surgery, should be limited to specific situations. This report discusses the management of patients with coexisting TMD and skeletal malocclusion. Current concepts in clinical and radiographic diagnosis are discussed, as well as an overview of noninvasive therapy. A case report is used to illustrate an approach to diagnosis and treatment planning in an individual with active TMD and a skeletal malocclusion requiring orthognathic surgery for correction.

Orthognathic surgery versus orthodontic camouflage in the treatment of mandibular deficiency.

Surgical correction of Class II malocclusions, when associated with mandibular deficiency, often has improved results with combined orthodontic and surgical correction compared with orthodontic treatment alone. Strong consideration of surgical correction of mandibular deficiency should be based on the following questions: 1) Do the patient's goals for treatment place a high priority on improvement in facial esthetics? As a corollary, even patients who are not particularly concerned with facial esthetics, but who may have a worsening in facial appearance as a result of orthodontic camouflage, should be considered for surgical correction. This may include patients with lack of upper lip support, an obtuse nasolabial angle, a large nose, and a long lower face height, all of which may become more apparent as a result of orthodontic camouflage treatment. 2) Are the orthodontic movements required in excess of the envelope of discrepancy so that adequate orthodontic correction may not be achieved? 3) Could orthodontic-surgical treatment result in a significant decrease in treatment time? An example would be when surgical treatment in combination with orthodontics could be accomplished without extraction, whereas orthodontic treatment alone would require extraction and space closure. 4) Is there adequate patient compliance? Would orthodontic treatment alone be as ineffective without adequate patient cooperation? 5) Are the risks of surgery within acceptable levels? Are the benefits of surgical treatment, as previously described, obvious?

Current concepts in management of facial trauma.

Open reduction and internal fixation have become routine in facial fracture treatment. Methodical evaluation and treatment planning should be based on the patient's injuries, extenuating factors, and the surgeon's experience. After initial treatment, patients with facial trauma may require orthodontic alignment of teeth, endodontic therapy, osteotomies, implants, vestibuloplasties, and scar revisions to achieve an acceptable functional and cosmetic result. The oral and maxillofacial surgeon is best qualified to coordinate and help deliver this interdisciplinary approach to treatment.

Temporary silastic implantation following discectomy in the primate temporomandibular joint.

Silastic (Dow Corning, Midland, MI) has been used in the surgical treatment of a variety of temporomandibular joint (TMJ) disorders as either a permanent or temporary implant. In this study four Macaca fascicularis monkeys underwent bilateral TMJ discectomies and high condylar shaves. The experimental side was treated with a Silastic sheet implant which was removed at 3 months postdiscectomy. The contralateral side was left without an implant and served as a control. Animals were killed at 3, 4, 5, and 6 months postoperatively. A fibrous connective tissue capsule was found around the Silastic implant at all time intervals. This capsule formed a single joint space between the inferior surface of the glenoid fossa and articulating surface of the condyle. Three months following implant removal, the capsule was still present and there was no significant inflammatory cell infiltrate. The severity of the degenerative changes was decreased on the implant side.

[Autogenous auricular cartilage grafts after TMJ discectomy. A comparative study with and without silastic implants]. / Autogener Ohrknorpel nach Diskektomie des Kiefergelenkes. Eine Vergleichsstudie mit und ohne Silastikimplantation.

Following TMJ discectomy an interposed autogenous graft is to be preferred. In our study we examined the effect of short-term Silastic grafts on the surrounding tissue. When the silicone material was removed 12 weeks after surgery, foreign body granulations were present only in those cases where the Silastic surface had been mechanically roughened.

Possible spread of African horse sickness on the wind.

Analyses of outbreaks of African horse sickness showed that movement of infected Culicoides midges on the wind was most likely responsible for the spread of the disease over the sea from Morocco to Spain in 1966, from Turkey to Cyprus in 1960, and from Senegal to the Cape Verde Islands in 1943. The pattern of spread of the epidemic in the Middle East in 1960 could have been laid down by the infected midges carried on spells of south-east winds, and analyses of outbreaks in Algeria in 1965 and India in 1960 also suggested windborne spread of the disease. Each spread occurred when the presence of virus, host and vector coincided either with a spell of winds unusual for a particular time of year (Spain, Cyprus, Cape Verde Islands and Algeria) or with a series of disturbances usual at that time of the year (Middle East and India). Inferred flight endurance of the midge varied up to at least 20 h and flight range from 40 to 700 km. Flight occurred when temperatures were likely to have been in the range of 15-25 degrees C if it was at night or 20 to about 40 degrees C if it was by day.It is suggested that likely movements of midges on the wind can be estimated from synoptic weather charts, and should be taken into account when planning control of the disease in the face of an outbreak. Such control includes a ban on movement of horses, vaccination and spraying of insecticide.The risk of spread to countries outside the endemic areas should be assessed by reference to possible wind dispersal of infected midges.

Lag screw versus position screw techniques for rigid internal fixation of sagittal osteotomies: a comparison of stability.

Both lag screw and position screw techniques have potential advantages and disadvantages when used for securing sagittal osteotomies of the mandible. This study evaluated 56 patients undergoing bilateral sagittal split osteotomies for mandibular advancements. Osteotomies were fixed with either a position screw or lag screw technique using 2-mm self-threading screws. Five cephalometric points and two angles were used to evaluate skeletal changes. There were no statistically significant differences in the postsurgical movement of point B or the mandibular incisor. There were slight statistically significant differences in the horizontal and vertical movements of gonion. Overall, similar postoperative stability existed in both groups. Gonion and gonial angle changes were detected cephalometrically but had no effect on the clinical outcome.

Arterial blood gas levels after midazolam or diazepam administered with or without fentanyl as an intravenous sedative for outpatient surgical procedures.

The purpose of this study was to compare arterial blood gas measurements made during the baseline, initial sedation, maintenance, and recovery periods in patients sedated with midazolam and saline (MS), midazolam and fentanyl (MF), diazepam and saline (DS), and diazepam and fentanyl (DF). During induction both the MF and the DF groups had significantly lower average PO2, pH, and O2 saturations and significantly higher PCO2 values than either the MS or the DS group. While the differences were not as great, the same was also true during the maintenance phase of the procedure. During recovery, patients receiving MF had lower average PO2, pH, and O2 saturation and higher PCO2 values than the MS or the DF group. Patients receiving MF had significantly lower average PO2, pH, and O2 saturation levels and significantly higher average PCO2 levels during all three postsurgical periods than at baseline. Patients receiving DF had significantly lower average PO2, pH, and O2 saturation levels and significantly higher Pco2 levels during both induction and maintenance than at baseline.

Autogenous dermal grafts for repair of temporomandibular joint disc perforations.

In five Macaca fascicularis monkeys bilateral 5-mm perforations of the intra-articular disc were followed by unilateral repair with autogenous dermal grafts. The monkeys were killed at three, six, 12, 24, and 36 weeks after surgery. The temporomandibular joints (TMJs) were removed en bloc, decalcified, and sectioned in the sagittal plane for histologic examination. All of the control untreated disc perforations, with the exception of one, failed to heal. With all of the grafted disc perforations, viable dermis and fibrous connective tissue proliferation were seen in the area of the repaired perforation. Therefore, autogenous dermal grafting appears to be an acceptable technique for repair of the damaged disc in degenerative joint disease of the TMJ.