Colour Doppler induced streaming: an indicator of the liquid nature of lesions.

As sound waves traverse tissue, interaction with reflecting or absorbing obstacles results in a transfer of momentum from the wave to the medium. This generates a local force in the direction of propagation. If this occurs in a fluid medium, sufficient pressure may be generated to cause flow--"streaming". Generally, it is difficult to demonstrate this streaming in images using the usual diagnostic B-mode intensities, but the increased intensities in a colour Doppler (or power) region of interest enhance the phenomenon. This allows streaming to be both visualized by the motion of small particles and detected by colour change on the colour Doppler B-mode image. Borders of streaming between the simple grey scale image and the colour region may be easily seen, with retrograde flow in the regions subjected to a lower intensity. This phenomenon has been demonstrated in ocular, scrotal, thyroid, breast, ovarian and inflammatory collections or lesions, confirming the liquid nature, occasionally of fluid which is very echogenic due to contained debris. The technique is recommended as another tool which is available to most general ultrasound departments and will assist in the characterization of tissue.

The response of hamsters to primary and secondary infection with Trichinella spiralis and to vaccination with parasite antigens.

The duration of primary infections with T. spiralis was dose-dependent with greater proportional loss of worms from heavily infected hamsters and longer persistence of worms in syngeneic DSN hamsters carrying initially low intensity infections. Intestinal worms were lost more rapidly from challenged immunized animals with over 80% loss of established worms by day 6 post infection, but survival of residual worms for a further 2 weeks. Hamsters carrying initially more than 140 intestinal worms began to lose weight during the second week indicating severe pathology at this stage of infection. Mucosal mast cell numbers increased from 50 cells/20 villus crypt units in uninfected animals to a peak in excess of 150 during week 4 pi, although intestinal mastocytosis persisted long after the loss of the majority of adult worms. Serum antibody responses to muscle stage larval antigen were detected in week 3 and increased subsequently. Both mastocytosis and antibody responses were more intense on secondary exposure to infection. Hamsters vaccinated with muscle stage larval antigen showed only a moderately accelerated loss of the intestinal phase but the fecundity of worms was severely suppressed. Overall it was concluded that the hamster host provided a model of trichinellosis that, in many respects was closer than mice and rats to the pattern of infection seen in economically and clinically important host species.

Energy expenditure of trans-tibial amputees during ambulation at self-selected pace.

The purpose of this investigation was two-fold: 1) to compare the metabolic cost (VO2), heart rate (HR), and self-selected speed of ambulation of trans-tibial amputees (TTAs) with those of non-amputee subjects; and 2) to determine whether a correlation exists between either stump length or prosthesis mass and the energy cost of ambulation at the self-selected ambulation pace of TTAs. Subjects were thirty-nine healthy male non-vascular TTAs between the ages of 22 and 75 years (mean +/- sd = 47 +/- 16). All had regularly used their prosthesis for longer than six months and were independent of assistive ambulation devices. Twenty-one healthy non-amputee males aged 27-47 years (31 +/- 6) served as controls. Subjects ambulated at a self-selected pace over an indoor course, with steady-state VO2, HR, and ambulation speed averaged across minutes seven, eight and nine of walking. Results showed that HR and VO2 for TTAs were 16% greater, and the ambulation pace 11% slower than the non-amputee controls. Significant correlations were not observed between stump length or prosthesis mass, and the energy cost of ambulation. However, when the TTA subject pool was stratified on the basis of long and short stump length, the former sustained significantly lower steady-state VO2 and HR than the latter while walking at comparable pace. These data indicate that stump length may influence the metabolic cost of ambulation in TTAs.

Spontaneous burst fracture of the thoracolumbar spine in osteoporosis associated with neurological impairment: a report of seven cases and review of the literature.

This is a report of seven patients suffering from osteoporosis, who sustained unstable burst fractures in the thoracolumbar spine associated with neurological impairment, without trauma. The manner of presentation, the neurological involvement, the radiological findings, as well as the surgical treatment with respect to functional and neurological recovery are discussed.

The CAT-CAM socket and quadrilateral socket: a comparison of energy cost during ambulation.

Twenty unilateral trans-femoral amputees fitted with either the Contoured Adducted Trochanteric-Controlled Alignment Method (CAT-CAM) socket (n = 10) or the quadrilateral (QUAD) socket (n = 10), and a "non-amputee" control group (n = 10) participated in the study. Subjects meeting the following criteria were studied: healthy males between the ages of 18 and 55 years, amputation due to non-vascular pathology, an unaffected sound limb, at least six months use of the test prosthesis, and a minimal stump length of 15 cm. Subjects ambulated in two randomized trials separated by 20 minutes of rest at 2 assigned speeds: a pace reflecting normal walking speed (97 m/min = 2.5 mph) or a slower speed (48.5 m/min = 1.25 mph). Heart rate (HR) and Oxygen uptake (VO2) measured during steady state walking were analyzed via two-way ANOVA. Differences among means were further analyzed using Tukey post hoc and simple effects tests. Significant differences were observed between the control group and CAT-CAM subjects with respect to VO2 (p < 0.05) and HR (p < 0.01) at the slower speed. The control group and subjects using the QUAD socket also differed with respect to VO2 (p < 0.01) and HR (p < 0.01) at the slower pace. Faster pace required more energy expenditure (p < 0.01) and produced higher HR (p < 0.01) than slower speeds. At faster pace, a significantly higher energy expenditure in the QUAD than the CAT-CAM group was observed (p < 0.01). It is concluded that ambulating at normal pace using the CAT-CAM socket design uses less energy than when using a QUAD socket design.

Femoral artery pseudo-aneurysm: ultrasound guided compression repair.

Pseudo-aneurysm is an uncommon complication of catheterization of the femoral artery. The recently described technique of repair of femoral artery pseudo-aneurysms by ultrasound guided compression is discussed and three cases using this treatment presented.

Complete lateral dislocation of the talus without fracture.

A pure total dislocation of the talus from all its surrounding joints without a concomitant fracture is an extremely rare injury. Because of an inability to reduce this talus dislocation by closed methods, we performed an open reduction and stabilization with Steinmann pins. At 2-year follow-up, our patient had good functional and good roentgenographic results with no posttraumatic avascular necrosis of the talus or posttraumatic arthritis. To our knowledge, this is the first report regarding complete talar dislocation without an associated fracture.

Biomechanical gait analysis in obese men.

The purpose of this study was to identify and compare the kinematic components of the walking gait of obese men to those of nonobese men. Self-paced walking trials of 12 obese volunteers, ranging in age from 30 to 47 years and in obesity from 70% to 99% above ideal body weight, were recorded via cinematography. The following findings were recorded: (1) obese persons (1.09m/sec) walk significantly (p less than .001) slower than nonobese subjects (1.64m/sec); (2) obese persons take significantly (p less than .001) shorter strides (1.25m vs 1.67m) and exhibit step widths (.16m) twice those of nonobese persons (.08m); (3) mean hip abduction angles of the obese are significantly (p less than .001) different at some events of the walking cycle from the hip angles of nonobese persons; (4) mean hip and knee flexion angles are not significantly different for obese and nonobese subjects; and (5) obese individuals demonstrate a walking gait pattern with significantly greater (p less than .001) mean magnitude of ankle dorsiflexion and lesser (p less than .001) mean magnitude of ankle plantar flexion than nonobese subjects throughout the walking cycle. It is concluded that obese individuals display a walking gait that follows a normal pattern but some of the temporal and angular components of their gait are different from those of nonobese persons mainly because of the excessive adipose tissue inside their thighs.

Acetabular protrusion in thalassemia. A report of four cases.

Four female patients with thalassemia intermedia developed secondary acetabular protrusion. These cases could be the first reported cases of nontraumatic acetabular protrusion in patients with thalassemia. The rarified pelvic bone may be due to medullary hyperplasia, iron overload, or disordered calcium metabolism in conjunction with osteomalacia. The fact that currently patients with beta-thalassemia have a longer life expectancy may explain the recent observation of this entity, which should become more familiar to orthopedic surgeons who treat thalassemia patients in the future.