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Recent much-publicized increases in pertussis case reports in some countries with high vaccine coverage have raised concerns about its current and future control. The ubiquity of this trend, however, remains unexamined. In an attempt to paint a global picture, we used case counts to determine which countries experienced statistically significant trends in incidence over the past two decades and to map changes in incidence during this period. These data reveal that pertussis resurgence is not a universal phenomenon. The heterogeneity in incidence trends, even in countries with superficially similar demography, socioeconomic conditions and vaccination programmes, is striking and requires explanation. In this opinion piece, we review and assess the multifaceted proposed explanations incorporating evolution, population dynamics, and the details of immunization programmes. While we do not solve the riddle that is pertussis epidemiology, we highlight critical aspects that are likely to hold the key to understanding its worldwide epidemiology.

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The bulk and retail water companies of the greater Melbourne area are developing the 2009 Metropolitan Sewerage Strategy to provide sustainable sewerage services to 2060. The objective of the strategy is to establish long term principles and near term actions to produce a robust sewage management system for Melbourne. Melbourne's existing sewerage system is largely centralised and discharges to two major treatment plants. Several small satellite treatment plants service local urban areas generally more distant from the centralised system. Decentralised and on-site wastewater systems are options for future sewage management and could play a role in local recycling. A portfolio of 18 on-site and decentralised concept designs was developed, applicable to the full range of urban development types in Melbourne. The concepts can be used in evaluation of metropolitan system configurations as part of future integrated water cycle planning. The options included secondary and tertiary treatment systems incorporating re-use of water for non potable uses, urine separation, black and greywater separation and composting toilets. On-site and cluster treatment systems were analysed. Each option is described by its indicative capital and operating costs, energy use and water and nutrient balances. This paper summarises and compares the portfolio mix of decentralized and on-site options in Melbourne's context.

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OBJECTIVE: This study evaluates the viscosupplementation material Hylan A and B in relation to its: (1) joint distribution, residence time and mechanism of removal and/or degradation, and (2) associated synovial fluid leukocyte response, in a goat model. METHOD: One green fluorophore was covalently bound to the Hylan A low molecular weight (MW) molecule (viscous fluid fraction) and a second red fluorophore was covalently bound to Hylan B high MW molecule (globule gel-like fraction). Goats were anesthetized and the right knee received 0.5 ml of test material or unbound fluorophore dyes. Gross and histological serial evaluations were performed over an 8-week period. RESULTS: By 24 h, the non-covalently linked control labels were not present in the tissues. For the covalently linked labels, the green fluorophore Hylan A diminished rapidly in intensity grossly but persisted to 28 days within the superficial synovial and articular cartilage layers in histologic sections. The red fluorophore linked Hylan B was seen only as globules in the synovial fluid. Mononuclear cells remained attached to these globules for 28 days and showed phagocytosis of the globules as well as the green fluorophore Hylan A. The globules were absent at 56 days after injection. The synovial fluid leukocyte count peaked at 24h (mean 9767 cells/mm(3) +/- 8574 S.D.) and declined by 7 days. CONCLUSIONS: The smaller MW Hylan was removed more rapidly than the higher MW Hylan. The globules were degraded by a different mechanism involving monocytes/macrophages on the surface of the higher MW globules.

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The symptomatic degeneration of articular cartilage and associated arthritis is among the most prevalent chronic conditions in the United States and the population most at risk is increasing. It is the leading cause of limitations in activities of daily living and is second to heart disease in causing work disability. The current and future socioeconomic impact of chronic articular cartilage disease on the healthcare system will be magnified by increasing numbers of patients who will seek relief of their symptoms and their disability to remain active. Because these individuals live longer and remain active, the proportion of their life living with symptoms and disability from articular cartilage degeneration increases. The economic, psychologic, and social impact of degenerative articular cartilage can be enormous for these individuals but it also impacts their family and society. The direct traditional medical costs and indirect economic and wage loss from arthritis in individuals the United States has reached in excess of $65 billion annually and is expected to increase as the population ages. In addition, the expenditures for complementary and alternative professional services and therapies for arthritis is increasing and is also in the billions of dollars annually. Because of these escalating costs, documenting the value of the patient and cost effectiveness to society of prevention and treatment programs for symptomatic articular cartilage degeneration will be required.

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The anterior cruciate ligament (ACL) is frequently injured during both recreational and competitive activity. It is common to see patients who have ruptured both ACLs at different times. Intercondylar notch width, notch morphology, gender, and family history have all been implicated as factors that may predispose an individual to contralateral ACL rupture following unilateral injury. Simultaneous bilateral ACL rupture is a rare occurrence. Only 1 other case has previously been reported. We report the case of a 17-year-old high school cheerleader who sustained simultaneous bilateral ACL ruptures. Some of the commonly implicated risk factors for ACL rupture are examined and a review of the literature is also presented.

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BACKGROUND: Full-thickness defects measuring 3 mm in diameter have been commonly used in studies of rabbits to evaluate new procedures designed to improve the quality of articular cartilage repair. These defects initially heal spontaneously. However, little information is available on the characteristics of repair of larger defects. The objective of the present study was to define the characteristics of repair of 6-mm full-thickness osteochondral defects in the adult Spanish goat. METHODS: Full-thickness osteochondral defects measuring 6 x 6 mm were created in the medial femoral condyle of the knee joint of adult female Spanish goats. The untreated defects were allowed to heal spontaneously. The knee joints were removed, and the defects were examined at ten time-intervals, ranging from time zero (immediately after creation of the defect) to one year postoperatively. The defects were examined grossly, microradiographically, histologically, and with magnetic resonance imaging and computed tomography. RESULTS: The 6-mm osteochondral defects did not heal. Moreover, heretofore undescribed progressive, deleterious changes occurred in the osseous walls of the defect and the articular cartilage surrounding the defect. These changes resulted in a progressive increase in the size of the defect, the formation of a large cavitary lesion, and the collapse of both the surrounding subchondral bone and the articular cartilage into the periphery of the defect. Resorption of the osseous walls of the defect was first noted by one week, and it was associated with extensive osteoclastic activity in the trabecular bone of the walls of the defect. Flattening and deformation of the articular cartilage at the edges of the defect was also observed at this time. By twelve weeks, bone resorption had transformed the surgically created defect into a larger cavitary lesion, and the articular cartilage and subchondral bone surrounding the defect had collapsed into the periphery of the defect. By twenty-six weeks, bone resorption had ceased and the osseous walls of the lesion had become sclerotic. The cavitary lesion did not become filled in with fibrocartilage. Instead, a cystic lesion was found in the center of most of the cavitary lesions. Only a thin layer of fibrocartilage was present on the sclerotic osseous walls of the defect. Specimens examined at one year postoperatively showed similar characteristics. CONCLUSIONS: Full-thickness osteochondral defects, measuring 6 mm in both diameter and depth, that are created in the medial femoral condyle of the knee joint of adult Spanish goats do not heal spontaneously. Instead, they undergo progressive changes resulting in resorption of the osseous walls of the defect, the formation of a large cavitary lesion, and the collapse of the surrounding articular cartilage and subchondral bone. CLINICAL RELEVANCE: As surgeons apply new reparative procedures to larger areas of full-thickness articular cartilage loss, we believe that it is important to consider the potential deleterious effects of a "zone of influence" secondary to the creation of a large defect in the subchondral bone. When biologic and synthetic matrices with or without cells or bioactive factors are placed into surgically created osseous defects, the osseous walls serve as shoulders to protect and stabilize the preliminary repair process. It is important to protect the repair process until biologic incorporation occurs and the chondrogenic switch turns the cells on to synthesize an articular-cartilage-like matrix. It takes a varying period of time to fill a large, surgically created bone defect underlying a chondral surface. The repair of such a defect requires bone synthesis and the reestablishment of a subchondral plate with a tidemark transition to the new overlying articular surface. The prevention of secondary changes in the surrounding bone and articular cartilage and the durability of the new reparative tissue making up the articulating surface are issues that must be addressed in future studies.

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Articular cartilage defects that are symptomatic and refractory to nonoperative treatment represent a clinical management challenge. Although there have been important advances in stimulating intrinsic repair mechanisms, cartilage regeneration, and other substitution techniques, to date none has unlocked the understanding necessary to duplicate normal articular cartilage. The objectives of treatment of cartilage lesions are to obtain pain relief, reduce effusions and inflammation, restore function, reduce disability, and postpone or alleviate the need for prosthetic replacement. As the field of articular cartilage repair continues to evolve rapidly, the most appropriate treatment option for an individual patient should be based on the pathologic characteristics of the lesion and the patient's symptoms and expectations. The orthopaedic surgeon needs to be familiar with both the existing and the newly emerging cartilage treatment techniques in order to best educate patients and meet their expectations for long-term benefits.

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Recent legislation has made captioned television programs common technology; consequently, televised programs have become more accessible to a broader public. In the United States, television captions are generally in written English, yet the English-literacy rates among people who are deaf are low compared to hearing peers. This research tests the accessibility of television by assessing deaf and hearing students' comprehension of captions with and without visuals/video based on their ability to respond correctly to questions about the script and central details. Results indicate that reading grade level is highly correlated with caption comprehension test scores. Across caption conditions, comprehension test scores of students who are deaf were consistently below the scores of hearing students. The captioned video provided significantly better comprehension of the script for students who are deaf, suggesting that visual stimuli provide essential information for viewers who are deaf, which improves comprehension of televised script.

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Advances in the fields of biotechnology and biomaterials offer the orthopaedic surgeon the exciting possibility of repair or regeneration of tissue lost to injury, disease, or aging. The promising area of tissue engineering represents a multidisciplinary approach aimed at solving some of the most perplexing biologic problems, namely, the creation of new tissues and organs similar to the original tissues and organs. In addition, strategies using new synthetic polymer formulations can facilitate tissue replacement and represent alternatives to tissue regeneration in certain conditions. Although biotechnology has broad application over many medical specialties, orthopaedics is receiving a large focus of the research effort devoted to techniques for developing bone, articular cartilage, ligaments, and tendons. Because bioengineered tissue and/or techniques to stimulate tissue regeneration soon may be used clinically, orthopaedic surgeons should have a working knowledge of the basic concepts involved. Terms, such as biomaterial, biotechnology, matrices of synthetic or biologic polymers or both, adhesion, cohesion, porosity, induction, conduction, stem cell, progenitor cell, mesenchymal cell, tissue growth factor, bone morphogenetic protein, mitogenic and chemotactic factors, and numerous other terms will become part of the working language of clinicians of the twenty-first century.

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Bioabsorbable screws composed of poly(L-lactic acid) (PLA) were used for graft fixation and studied prospectively with serial magnetic resonance imaging (MRI) scans at 8, 16, and 24 months after autogenous patellar tendon anterior cruciate ligament (ACL) reconstruction in 10 patients. Conventional spin echo, proton density, and T2-weighted double echo sequences were obtained, as well as T2-weighted fat-saturated fast spin echo sequences. All but one of the screws (19 of 20) were evident in all serial scans. These showed minimal decrease in size over time. The one screw that had completely disappeared 8 months after reconstruction had cracked during insertion. None of the reconstructed ACL grafts showed clinical instability, persistent effusions, or detectable adverse reactions to the screws. Two patients developed abnormal signal in the tibial tunnel: one developed fluid anterior to the graft, and the other developed increased signal within the graft. The abnormal signal resolved with time in both patients. Other than the preceding changes, no abnormalities were detected on conventional sequences. Fat-saturated fast spin echo sequences showed a variable amount of increased signal around the tunnels, suggesting edema or fibrovascular marrow changes. The changes noted near the tunnels on the fat-suppressed scans most probably represent a general reaction to surgical insult rather than a reaction to the bioabsorbable screws, as similar changes were noted at the patellar harvest site.

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Adaptive changes in the menisci and adjacent posterior capsule were documented within anterior cruciate ligament-deficient knee (stifle) joints in the goat model. These physical changes in the menisci and capsule developed over time and were associated with reduction in the initial (time zero) abnormal anterior tibial translation following transection of the anterior cruciate ligament. At 50 N of applied force, the normal goat knee joint has a total anterior-posterior translation of 0.6+/-0.1 mm (+/- SEM) at 45 degrees of flexion and 0.3+/-0.1 mm at 90 degrees. The translation immediately after transection (time zero) with 50 N of force was 8.2+/-0.5 mm at 45 degrees and 4.9+/-0.9 mm at 90 degrees. Within 8 months after transection and at 50 N of force, the treated knees had reduced translation values of 5.3+/-0.6 mm at 45 degrees of flexion and 2.9+/-0.5 mm at 90 degrees, or 35 (p<0.001) and 40% reductions, respectively, compared with the values at time zero. Magnetic resonance images of the ligament-deficient stifle joints, as well as gross measurements and image analysis after dissection, consistently demonstrated increases in cross-sectional area and volume of the menisci compared with the contralateral controls. These secondary changes were most pronounced in the posterior portion of the medial menisci, and histologic evaluation demonstrated hypercellularity with the accumulation of poorly organized collagen, reduced safranin O staining (proteoglycan matrix synthesis), a thickened capsule and capsule attachment, and increased vascularity at the meniscal capsule interface.

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UNLABELLED: The purpose of this study was to characterize the repair tissue that develops after removal of a portion of the patellar ligament for use as a graft. A six-millimeter-wide strip was obtained from the central portion of the patellar ligament with tibial and patellar bone plugs from one knee (stifle joint) of eight goats. The repair tissue that formed in the defect was characterized in terms of its structural, material, histological, and ultrastructural properties twenty-one months after the operation. The contralateral patellar ligament served as a control. Representative specimens were taken from the proximal, middle, and distal portions of the repair tissue and the control tissue for histological study and examination with transmission electron microscopy. The six-millimeter-long defect filled with repair tissue that increased the cross-sectional area by a mean of 42 per cent compared with the control values (p < 0.05). The maximum force to failure and the ultimate stress of the repair tissue were significantly decreased (by a mean of 51 and 65 per cent, respectively) compared with those of the controls (p < 0.001 for both). The stiffness also was reduced, by a mean of 27 per cent, but this was not significant (p > 0.05). Magnetic resonance imaging of the donor site showed slightly increased signal intensity compared with the intensity on the control side. Histological sections from the donor site contained collagenous (scar) tissue that was less organized, more cellular, and more vascular than the control tissue. Evaluation of the ultrastructure revealed that the repair tissue was composed primarily of collagen fibrils with a small diameter (range, fifty to 100 nanometers). CLINICAL RELEVANCE: The results of the present study suggest that the repair tissue that develops after removal of a strip of the patellar ligament for use as a graft is not comparable with normal tissue in terms of its structural, material, histological, and ultrastructural properties by twenty-one months. This should be kept in mind when this repair tissue is considered for use as a graft for revision of a reconstruction of the anterior cruciate ligament.

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This study examined the role of social support and need for support on anxiety among 61 women, graduate students, by administering the Jackson Personality Inventory, the Personality Research Form, and the Social Support Network Inventory. One-way analysis of variance showed a significant effect for source of support on support received. Friends were cited most frequently and graduate advisers the least. Two-way analyses of variance showed significant main effects of need for support and support from adviser on anxiety scores. High scores on anxiety were a function of high need for support and, separately, of low social support. Results are discussed in terms of the need for longitudinal studies of the relationships between these variables to consider implications for adult development.

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