Analysis of the intercondylar notch by computed tomography

The purposes of this study were to document the dimensions and configuration of the intercondylar notch in the normal knee; to compare normal knee intercondylar notches to those of knees with unilateral and bilateral ACL tears to determine if there is a relationship between intercondylar notch stenosis and ACL tears; and to determine if generalized ligamentous laxity is associated with intercondylar notch stenosis and ACL tears. Three groups were compared: Group I, bilateral ACL tears; Group II, unilateral tears; and Group III, normal knees. Notch dimensions were computer-generated from CT scans. All patients were examined for ligamentous laxity. Statistically significant differences were found between normal and ACL-injured knees in regard to opening notch angle, ratio of notch width at two-thirds of the notch length to condylar width, and ratio of maximum notch width to condylar width, suggesting a significant association between anterior outlet stenosis and unilateral and bilateral ACL tears. The shapes of the notches were determined from tracings of the distal CT scan. Shapes ranged from inverted U to cresting wave. Narrow notches tended to be waveshaped, but more study is needed in this area. Notch-plasty is recommended for those with documented stenosis. The ratio of maximum notch width at two-thirds of the notch height to maximum condyle width should not be much less than 0.2, and the opening notch angle should be at least 50 degrees.     

Sonography of acute appendicitis in childhood: perforation versus nonperforation.

We evaluated the sonographic findings in 133 consecutive children referred for suspected appendicitis. Fifty-eight of these patients (44%) ultimately underwent surgery, with 54 of these proved to have acute appendicitis. Thirty-one (58%) of the 54 had nonperforated appendicitis, and 23 (43%) had evidence of perforation. Previously described sonographic findings that have been employed in the diagnosis of appendicitis were evaluated, with the presence or absence of these findings being compared in patients with non-perforated and perforated appendicitis. In those patients who did not undergo surgery, the following findings were documented and compared to the findings in patients with proved appendicitis: (1) an identifiable appendix and its sonographic characteristics, (2) fluid localized to the right peritoneal reflection or periappendiceal region, or both, (3) free pelvic fluid, and (4) right lower quadrant adenopathy. Our results suggest that high-resolution, real-time sonography, using graded compression, is very sensitive in the identification of acute nonperforated appendicitis. Perforated appendicitis, however, can be a more difficult diagnosis because the appendix frequently decompresses with perforation and yet may not "wall off" or form a well-defined abscess. As a result, the appendix can be very difficult to identify.     

T cell-mediated immunity in the lung: a Cryptococcus neoformans pulmonary infection model using SCID and athymic nude mice.

T cells are important in systemic anticryptococcal defenses, but a role in controlling an initial pulmonary infection has not been demonstrated. A murine model with intratracheal inoculation was developed to study the acquisition and expression of pulmonary T cell-mediated immunity against Cryptococcus neoformans. Infections with four strains of C. neoformans (305, 68A, 613D, and 52D) in two strains of mice (BALB/c and C57BL/6) were examined. Unencapsulated strain 305 and slowly growing strain 68A were readily controlled apparently by nonimmune pulmonary defenses, and no extrapulmonary dissemination was detected. Strain 613D grew progressively in the lungs and disseminated to the brain and spleen. Strain 52D initially grew rapidly in the lungs and disseminated to the spleen, but a clearance mechanism developed in the lungs after day 7 postinfection and in the spleen after day 28. SCID and athymic nude mice were unable to clear a strain 52D pulmonary infection, and a lethal disseminated infection occurred. Pulmonary clearance could be adoptively transferred into SCID mice infected with strain 52D by use of immune T cells from the spleen and lungs and hilar lymph nodes of infected immunocompetent donors. Furthermore, pulmonary clearance was almost 100-fold better in SCID mice that received immune T cells from the lungs and hilar lymph nodes than in those that received immune T cells from the spleen, even though equivalent levels of delayed-type hypersensitivity were transferred by both cell populations. These adoptive transfer studies suggested that the lung and hilar lymph node T cells from immune animals either are enriched in such a way as to mediate protective immunity or home to the lungs better than do splenic T cells.     

Murine model of pulmonary anthrax: kinetics of dissemination, histopathology, and mouse strain susceptibility

Bioweapons are most often designed for delivery to the lung, although this route is not the usual portal of entry for many of the pathogens in the natural environment. Vaccines and therapeutics that are efficacious for natural routes of infection may not be effective against the pulmonary route. Pulmonary models are needed to investigate the importance of specific bacterial genes in virulence, to identify components of the host immune system that are important in providing innate and acquired protection, and for testing diagnostic and therapeutic strategies. This report describes the characteristics of host and Bacillus anthracis interactions in a murine pulmonary-infection model. The infective dose varied depending on the route and method of inoculation. The germination process in the lung began within 1 h of inoculation into the lung, although growth within the lung was limited. B. anthracis was found in the lung-associated lymph nodes approximately 5 h after infection. Minimal pneumonitis was associated with the lung infection, but significant systemic pathology was noted after dissemination. Infected mice typically succumbed to infection approximately 3 to 4 days after inoculation. The 50% lethal doses differed among inbred strains of mice, but within a given mouse strain, neither the age nor the sex of the mice influenced susceptibility to B. anthracis.     

A political economic theory of the dental care market.

A theory of the dental care market is introduced which proposes that the vertically integrated (local/state/national) structure of the profession services as an organizational vehicle both for intra-professional debate and for developing provider-oriented dental care policy. We suggest that a special relationship exists between professionalism and professional regulation. Such regulation has functioned simultaneously to limit competition and to foster a prized consumption commodity for providers: professionalism and professional esteem. The organized pursuit of this commodity inherently dampens competition. Professionalism itself plays a crucial role in: 1) securing for organized dentistry a form of state regulation in which the providers themselves are the principal decision-makers; and 2) influencing provider and consumer market behavior in several significant respects, the net result being the formation of maintenance of a type of "leadership cartel" in the local market. Thus, a political-economic theory of the dental care market formally acknowledges professionalism as valued by established dentists and recent graduates as a central determining influence. Traditional models of pure competition and monopoly emerge as special, extreme cases of the general theory. Hypotheses are offered regarding consumer and provider behavior, market dynamics, and health policy and regulation.