Experimental Malaria Infection Affects Songbirds' Nocturnal Migratory Activity.

Migratory animals encounter multiple parasite communities, raising concerns that migration may aid transport of infectious disease. How migration affects disease spread depends fundamentally on how disease affects migration, specifically whether infection alters individuals' migratory physiology and behavior. We inoculated white-throated sparrows (Zonotrichia albicollis) with avian malaria parasites (Plasmodium sp.), monitored parasite loads for 5 wk as the birds reached spring migratory condition, and compared nocturnal migratory restlessness (Zugunruhe), body composition (fat, lean, and whole-body mass), and hematocrit among experimentally infected birds, sham-inoculated birds, and birds that were exposed to parasites but resisted infection. Migratory restlessness increased over time in the study, but the rate of change varied between sham (control) birds, infected birds, and birds that resisted infection. We were unable to detect any effects of malaria exposure on body condition. Our findings suggest that encountering parasites affects migratory activity, regardless of whether infection occurs or is resisted.

Spatial coding of enantiomers in the rat olfactory bulb.

Because of their unique properties, enantiomers (pairs of mirror-symmetric, nonsuperimposable molecules that differ only in optical activity and their interaction with other chiral molecules) have been instrumental in demonstrating that olfactory perception relies on molecular shape. To investigate how molecular structure is encoded by the olfactory system, we combined behavioral discrimination tasks with optical imaging of intrinsic signals. We found that rats can behaviorally discriminate members of a wide range of enantiomer pairs, and imaging revealed enantiomer-selective glomeruli in the olfactory bulb, indicating that the spatial pattern of glomerular activity provides sufficient information to discriminate molecular shape.

Optical imaging of odorant representations in the mammalian olfactory bulb.

We adapted the technique of intrinsic signal imaging to visualize how odorant concentration and structure are represented spatially in the rat olfactory bulb. Most odorants activated one or more glomeruli in the imaged region of the bulb; these optically imaged responses reflected the excitation of underlying neurons. Odorant-evoked patterns were similar across animals and symmetrical in the two bulbs of the same animal. The variable sensitivity of individual glomeruli produced distinct maps for different odorant concentrations. Using a series of homologous aldehydes, we found that glomeruli were tuned to detect particular molecular features and that maps of similar molecules were highly correlated. These characteristics suggest that odorants and their concentrations can be encoded by distinct spatial patterns of glomerular activation.

The basics of competitive diving and its injuries.

This article reviews the history of competitive springboard and platform diving, the basic rules of competition, and the epidemiology and pathomechanics of diving injuries, with reference to the specific parts of the dive. Injuries are more commonly associated with the entry phase of the dive, and are more frequently associated with back and reverse dives, and with platform rather than springboard diving. The most frequently injured areas are the wrist, shoulder, and lumbar spine. It is crucial that treating medical professionals understand the physical demands of the sport and the pathogenesis of injury to affect successful treatment and prevention strategies, and to determine safe return to participation after injury.

Saline magnetic resonance arthrography in the evaluation of glenohumeral instability.

Sixty-five patients underwent magnetic resonance (MR) shoulder arthrography. Forty-eight of these patients underwent examination under anesthesia (EUA). MR images were retrospectively evaluated for signs felt to be imaging indicators of shoulder instability, including evaluation of various capsular measurements and the presence of glenoid labral tears, as well as Hill-Sachs fractures. Statistical analysis of the results showed that no correlation between capsular indicators with EUA-documented instability was found. However, there was a statistically significant correlation between the presence of a Bankart cartilaginous deformity (p = 0.000) and Hill-Sachs fractures (p = 0.022) with EUA-documented instability. Sensitivity to labral tears was 89% and specificity was 98%, whereas Hill-Sachs fracture detection was 69% and 87%, respectively. We believe that MR saline arthrography is of benefit in the evaluation of the anterior labrum when unenhanced MR imaging is inconclusive, and we speculate on the role of MR arthrography as a primary investigative tool.

Skeletal muscle profiles in elite springboard and platform divers.

This investigation determined the vastus lateralis muscle fiber composition, as well as leg power and strength, in a group of 10 world class divers. Male divers had a low mean percentage of Type I fibers (36%), which was consistent with the functional demands of their sport, whereas females had a mean value of 61%. The ratio of Type I/Type II cross-sectional fiber area was 0.95 in females and 0.82 in males. Angle-specific torque-velocity relationships, derived from Cybex testing of the knee extensors, revealed high torque values in males but not in females. The observed male-female differences have no clear explanation, unless muscle fiber composition has greater importance in the more difficult dives executed by men.

Skeletal muscle profiles among elite long, middle, and short distance swimmers.

Skeletal muscle profiles of fiber composition and leg power and strength were obtained in 30 national caliber swimmers (20 males, 10 females). Subjects were classified into three groups based upon the distance of their primary events [long distance (LDS), middle distance (MDS), and short distance (SDS) swimmers]. Intergroup analyses showed that the LDS group had the highest values of percent Type I muscle fiber composition (percent Type I and percent Type I area), and the lowest values of leg power and strength values (vertical jump and torque-velocity relationships). In addition, when grouped by Type I fiber composition, subjects having greater than or equal to 50% Type I fibers had significantly lower vertical jump and torque values than those having less than 50% Type I fibers. Overall, the compositional and functional measurements were consistent with the specific metabolic and contractile demands of the different swim groups.

Stress Fracture Diagnosis by Computer-Assisted Thermography.

In brief: To compare infrared thermography, radionuclide bone scanning, and routine x-ray in diagnosis, a prospective blind study was conducted on 17 athletes (ten men, seven women) who had exertional leg pain compatible with stress fracture. The athletes with 'hot' patterns were unable to resume their original activity, while those with 'cold' patterns were able to resume activity. Additionally, specific soft-tissue syndromes were identified. The data indicate that thermography may be an accurate, noninvasive new way to distinguish stress fracture from other causes of shinsplint syndromes in runners. Applied repeatedly, this technique could be used to follow the course of bone healing, permitting the earliest safe return to activity.

Chrysosporium, a new causative agent in osteomyelitis. A case report.

A 24-year-old black man presented with a two-month history of swelling of the right ankle. Roentgenograms were initially read as negative. One month later the patient returned with increased pain and swelling, and roentgenograms demonstrated a large lucency involving the distal tibia. Bone scanning revealed extension of the lesion proximally, to 6 cm below the knee. Biopsy of a large tibial abscess demonstrated histocytic giant cells with budding yeasts and septate mycelia. Chrysosporium was isolated from cultures. Amphotericin B was used to treat the patient. Clinically, the infection healed within four months in a short-leg cast. Although Chrysosporium is usually a contaminant, its presence in cultures and histologic sections is evidence of pathogenicity.

Neurological sequelae of cervical spine trauma.

It is estimated that there will be 5,000 new spinal cord injured patients each year. Prolonged survival has resulted from better understanding of the pathophysiology of cord damage, as well as from the advances in antibiotic and ventilatory therapy. Most well-motivated patients with lesions at or below C5 can attain a level of independence which obviates institutional care. Regional spinal injury centers have done much to increase the survival of and quality of life of cord injured patients. These realities make initial care of patients with acute traumatic lesions of the cervical spine of paramount importance. Neurologic function at both the nerve root and cord levels can be adversely affected by excessive motion of the unstable spine. Early evaluation of X-rays must therefore be carried out in an attempt to determine the stability of the spine.

Reconstruction of the posterior cruciate ligament using the semimembranosus tendon.

The semimembranosus tendon was successfully used as a posterior cruciate ligament substitute in a 27-year-old man who sustained an isolated tear of the ligament. Two years after the operation, he has no feeling of instability, and has normal hamstring strength, power, and endurance as tested on the Cybex II dynamometer.

Treatment of interotrochanteric fractures with the Jewett nail: experience with 1,015 cases.

During the period 1957 to 1976, 1,015 Jewett nails were inserted for intertrochanteric hip fractures. This is one of the largest series of intertrochanteric fractures studied at one institution using one method of treatment. Anatomic reduction was attempted in almost all cases regardless of comminution. Medial or valgus displacement was rarely carried out on purpose. The average delay to surgery was 2.1 days after admission. Most parients were on bed-chair status on the first postoperative day and began toe-touching ambulation 10 to 14 days after surgery. Routine anticoagulation was not employed. The reduction and nail placement were critical factors for fracture healing. Only 3.3% of patients with satisfactory nailings had nail-related complications, such as penetration or cutting out. Eighty-seven per cent of patients with poor nailings had these problems. Ninety-eight and seven-tenths per cent of fractures united, 1.3% went to nonunion, and necrosis was seen in 2 united fractures (0.4%).

Surgical repair of the interrupted Achilles tendon.

During the period 1965-1976 44 patients at our institution underwent open repair of ruptured or lacerated Achilles tendons. Patients were evaluated as to delay to surgery, type of repair, wound complications, incidence of rerupture, symptoms, and postoperative range of motion, mobility, and strength. Average followup was 3 years. Functional results were generally good. Rerupture (2.8%) and wound complications (6.8%) were infrequent. We conclude that the benefits of surgical repair appear to outweigh the potential complications, when compared with the reported incidence of rerupture and loss of strength and endurance following conservative management of these injuries.