The role of the transversal ligament on the atlantoaxial complex - Bending forces at C1/2 flexion limits in the elderly.

INTRODUCTION: Biomechanical functionality as well as trauma mechanisms of the atlantoaxial complex are still an issue of controversy. The transverse atlantal ligament is the strongest stabilizator. The present study aimed to analyze the bending forces of the transverse atlantal ligament and of the base of the odontoid in elderly specimens. METHODS: In this biomechanical study five cadaveric specimen with a mean age of 72 at death and bone mineral density measuring for 555.3 Hounsfield units on average were used. To analyze the strain of the transverse atlantal ligament and the dense base, strain gauges were used. A custom biomechanical setup was used to test each specimen at C1/2 flexion and the strain of the transverse atlantal ligament and the dens base (µm/m) were measured. FINDINGS: In four out of five, a rupture of the transverse atlantal ligament was observed, the mean force required for the ligament to fall was 175 N (min. 99.8 N; 249.2 N; SD 64.7) by a mean strain of 2102.9 µm/m (min. 1953.5 µm/m; max. 2272.3 µm/m; SD 189.7). In one specimen with the lowest Hounsfield units (155), the dens base fractured before the transverse atlantal ligament ruptured and no strain could be measured at the transversal ligament during movement afterwards. INTERPRETATION: The transverse atlantal ligament fails at an average of 175 N in the elderly, which is less than the value reported previously. In osteoporotic specimen the generated force to rupture the transverse atlantal ligament can fracture the dens itself.

Relationships between technique and bat speed, post-impact ball speed, and carry distance during a range hitting task in cricket.

The ability of a batsman to clear the boundary is a major contributor to success in modern cricket. The aim of this study was to identify technique parameters characterising those batsmen able to generate greater bat speeds, ball launch speeds, and carry distances during a range hitting task in cricket. Kinematic data were collected for 20 batsmen ranging from international to club standard, and a series of ball launch, bat-ball impact, and technique parameters were calculated for each trial. A stepwise multiple linear regression analysis found impact location on the bat face in the medio-lateral and longitudinal directions and bat speed at impact to explain 68% of the observed variation in instantaneous post-impact ball speed. A further regression analysis found the X-factor (separation between the pelvis and thorax segments in the transverse plane) at the commencement of the downswing, lead elbow extension, and wrist uncocking during the downswing to explain 78% of the observed variation in maximum bat speed during the downswing. These findings indicate that players and coaches should focus on generating central impacts with the highest possible bat speed. Training and conditioning programmes should be developed to improve the important kinematic parameters shown to generate greater bat speeds, particularly focussing on increased pelvis to upper thorax separation in the transverse plane.

The relationships between impact location and post-impact ball speed, bat torsion, and ball direction in cricket batting.

Three-dimensional kinematic data of bat and ball were recorded for 239 individual shots performed by twenty batsmen ranging from club to international standard. The impact location of the ball on the bat face was determined and assessed against the resultant instantaneous post-impact ball speed and measures of post-impact bat torsion and ball direction. Significant negative linear relationships were found between post-impact ball speed and the absolute distance of impact from the midline medio-laterally and sweetspot longitudinally. Significant cubic relationships were found between the distance of impact from the midline of the bat medio-laterally and both a measure of bat torsion and the post-impact ball direction. A "sweet region" on the bat face was identified whereby impacts within 2 cm of the sweetspot in the medio-lateral direction, and 4.5 cm in the longitudinal direction, caused reductions in ball speed of less than 6% from the optimal value, and deviations in ball direction of less than 10° from the intended target. This study provides a greater understanding of the margin for error afforded to batsmen, allowing researchers to assess shot success in more detail, and highlights the importance of players generating consistently central impact locations when hitting for optimal performance.

Reproductive hormonal patterns in pregnant, pseudopregnant and acyclic captive African wild dogs (Lycaon pictus).

African wild dogs are one of the most endangered canid species, with free-living populations declining as a consequence of habitat loss, disease and human conflict. Captive breeding is considered an important conservation strategy, but is hampered by a poor overall understanding of the reproductive biology of the species. To improve our basic knowledge, we studied hormone patterns in 15 female wild dogs using non-invasive faecal collections. By comparing longitudinal hormone profiles with behavioural and anatomical changes, females could be allocated among three reproductive classes: pregnant (n=1), pseudopregnant (n=9) and acyclic (n=4). We also monitored a single female in which contraception was induced with a deslorelin implant. Comparison of pseudopregnant and acyclic females showed that, in both classes, faecal oestradiol concentrations increased from anoestrus to pro-oestrus then declined into the oestrous and dioestrous phases. Progestagen concentrations rose steadily from anoestrus to the dioestrous phase in both pseudopregnant and acyclic females and, pseudopregnant females had significantly higher concentrations of progestagens than acyclic females in all phases of the oestrous cycle. Most females classed as pseudopregnant were found in female-only groups, suggesting that wild dogs are spontaneous ovulators. Furthermore, only one adult female did not ovulate, so suppression of reproduction in subordinates is likely to be behavioural rather than physiological.

The serological response of working farm dogs to a vaccine containing Leptospira interrogans serovars Copenhageni and Pomona, and L. borgpetersenii serovar Hardjo.

AIMS: To evaluate the serological response in dogs to a commercial vaccine for use in cattle containing cultured strains of Leptospira interrogans serovars Copenhageni and Pomona, and L. borgpetersenii serovar Hardjo. METHODS: Blood samples were obtained from 67 working farm dogs on 12 farms, and the microscopic agglutination test (MAT) was used to measure titres to the Leptospira spp. serovars Pomona, Hardjo, and Copenhageni. Samples with a titre of <1:25 were defined as seronegative. Dogs that were seronegative to both Pomona and Hardjo (n=33) were randomised to either the vaccination (n=20) or control (n=13) groups. Seven of these dogs were seropositive to Copenhageni. Vaccinated dogs were given the three-component vaccine subcutaneously on two occasions, 4 weeks apart. MAT titres were measured again in both groups 2 weeks after the second vaccination. RESULTS: Of the vaccinated dogs, 20/20 (100%) developed titres to serovar Pomona, and 16/20 (80%) had titres >100; for serovar Hardjo, 19/20 (95%) dogs had titres, with 18/20 (90%) being >100; and for serovar Copenhageni, 15/17 (88%) dogs that were initially seronegative had titres, with 6/17 (35%) being >100. The median titres for Pomona and Hardjo (200 (95% CI=179-359) and 200 (95% CI=176-379), respectively) were lower than for Copenhageni (50 (95% CI=26-124)) in dogs originally seronegative (p<0.001). There was no association between titres to the different serovars. Of the 13 unvaccinated dogs, two developed titres to serovar Pomona, and three to Hardjo. All titres were <100. CONCLUSIONS: The tested vaccine was effective in raising antibodies to the three serovars, although the titres do not guarantee protection. CLINICAL RELEVANCE: There has been a recent increase in cases of leptospirosis attributed to the serovar Pomona in dogs in New Zealand, but the vaccines licensed for use in dogs in New Zealand for the prevention of leptospirosis only protect against Copenhageni/Icterohaemorrhagiae. The vaccine tested in this study produced titres to Pomona and Hardjo that suggest the vaccine could be useful for reducing disease caused by these serovars in working dogs in New Zealand.

A serological survey of leptospiral antibodies in dogs in New Zealand.

AIM: To investigate the prevalence of titres to four endemic leptospiral serovars in dog sera from the lower half of the North Island, and the South Island of New Zealand submitted to diagnostic laboratories, and to explore the association between the prevalence of seropositive samples to leptospirosis and breed group, age group and sex. METHODS: Serum samples from 655 dogs residing in the central and lower North Island and from the South Island of New Zealand were sourced from the Massey University Veterinary Teaching Hospital and from submissions to New Zealand Veterinary Pathology in 2005. They were screened by the Microscopic Agglutination Test (MAT) against Leptospira interrogans serovars Copenhageni and Pomona and L. borgpetersenii serovars Hardjo and Ballum. Titres greater or equal to 96 were considered positive. Variables investigated for their association with the prevalence of seropositive samples to leptospirosis included serovar, breed, North vs. South Island, age and sex. RESULTS: Positive MAT titres to Leptospira interrogans serovar Copenhageni were found in 10.3 % of dogs (95% CI=8.1-12.9), and were more common than positive titres to other leptospiral serovars. Small breeds did not have a lower prevalence of Copenhageni titres than other breeds. Positive titres to Leptospira borgpetersenii serovar Hardjo were associated with breeds of dogs used as farm working dogs. There was no significant difference in the prevalence of positive leptospiral titres between dogs from the North or South Islands. Dogs greater than 12 years of age were less likely to have positive titres to Leptospira than younger dogs. No association was found between positive titres and sex. CONCLUSIONS: Breeds of dogs used as farm working were at greater risk of exposure to Leptospira borgpetersenii serovar Hardjo. Small breeds did not have a lower risk of seropositivity to Copenhageni than farm working breeds. Further study should be undertaken to confirm the prevalence of positive titres to leptospirosis in farm dogs and dogs resident in the South Island. CLINICAL RELEVANCE: The risk of dogs being exposed to Leptospira interrogans serovar Copenhageni, and requirement for vaccination against serovar Copenhageni, cannot be determined by geographical location or breed group. Vaccination against Leptospira borgpetersenii serovar Hardjo is likely to be beneficial in working dogs.

Subdural empyema in an HIV positive patient.

A subdural empyema with a Salmonella species as the likely causative organism is presented. We believe that this is the first reported case of such an infection in an HIV positive patient. The difficulties in treatment and diagnosis are discussed.

[Perforation of a temporary transvenous pacemaker electrode in the left hemithorax. Diagnostic value of echocardiography]. / Perforation einer passageren transvenösen Schrittmacherelektrode in den linken Hemithorax. Diagnostische Wertigkeit der Echokardiographie.

We report a rare malposition of a temporary transvenous pacemaker electrode. A pacemaker electrode was inserted in a patient with acute postero-lateral infarction. The correct position of the electrode tip was controlled by fluoroscopy. Capture and sensing functions worked regularly. Four days later, angina-pectoris-like complaints occurred again. Chest x-ray film revealed the tip of the electrode in the left hemithorax. Echocardiographic assessment showed a penetration through the interventricular septum into the left ventricle. The electrode passed the left ventricle, penetrated the anterior-lateral free wall and reached the left pleural space. A thoracotomy was performed immediately. The electrode was retracted under visual control. A spurting arterial bleeding from the left ventricle was secured with a purse-string ligature. This case report emphasizes the value of echocardiography in the evaluation of a malposition of a transvenous pacemaker electrode.

Impediments to the recovery of restitution by crime victims.

Restitution is unique among criminal justice policies by virtue of the widespread support it has attained from many diverse constituencies. Restitution has received such universal praise as a panacea for victims of crime that in recent years a number of American jurisdictions have adopted legislation that creates a presumptive norm that restitution be awarded in appropriate cases. Despite popular support for its increased use and enactment of enabling legislation, restitution continues to be underutilized in actual case dispositions. The authors suggest that the underuse problem will not be cured and the powerful potential that restitution holds as a criminal justice sanction will not be realized until a consensus regarding the definition of restitution is achieved, significant gaps in the technical data about how restitution is effectuated are closed, and practical impediments to awarding and collecting restitution are dissolved. These goals, in turn, cannot be met until policy makers confront and begin to resolve the inherent conflicts posed when a restorative sanction, such as restitution, is pursued in a criminal justice system that is primarily punitive in nature.