Identical genotypes of community-associated MRSA (ST59) and livestock-associated MRSA (ST9) in humans and pigs in rural China.

This study investigated the prevalence of MRSA in samples taken in households, with and without backyard pigs in villages in a rural area of Shandong Province, China. Community-associated MRSA and livestock-associated MRSA, belonging to ST59 and ST9, respectively, were identified in both humans and pigs. The genotypic and phenotypic comparison of isolates indicates that bidirectional transmission of MRSA has occurred between humans and pigs in the villages.

Syndromic surveillance of influenza activity in Sweden: an evaluation of three tools.

An evaluation was conducted to determine which syndromic surveillance tools complement traditional surveillance by serving as earlier indicators of influenza activity in Sweden. Web queries, medical hotline statistics, and school absenteeism data were evaluated against two traditional surveillance tools. Cross-correlation calculations utilized aggregated weekly data for all-age, nationwide activity for four influenza seasons, from 2009/2010 to 2012/2013. The surveillance tool indicative of earlier influenza activity, by way of statistical and visual evidence, was identified. The web query algorithm and medical hotline statistics performed equally well as each other and to the traditional surveillance tools. School absenteeism data were not reliable resources for influenza surveillance. Overall, the syndromic surveillance tools did not perform with enough consistency in season lead nor in earlier timing of the peak week to be considered as early indicators. They do, however, capture incident cases before they have formally entered the primary healthcare system.

Syndromic surveillance for local outbreak detection and awareness: evaluating outbreak signals of acute gastroenteritis in telephone triage, web-based queries and over-the-counter pharmacy sales.

For the purpose of developing a national system for outbreak surveillance, local outbreak signals were compared in three sources of syndromic data--telephone triage of acute gastroenteritis, web queries about symptoms of gastrointestinal illness, and over-the-counter (OTC) pharmacy sales of antidiarrhoeal medication. The data sources were compared against nine known waterborne and foodborne outbreaks in Sweden in 2007-2011. Outbreak signals were identified for the four largest outbreaks in the telephone triage data and the two largest outbreaks in the data on OTC sales of antidiarrhoeal medication. No signals could be identified in the data on web queries. The signal magnitude for the fourth largest outbreak indicated a tenfold larger outbreak than officially reported, supporting the use of telephone triage data for situational awareness. For the two largest outbreaks, telephone triage data on adult diarrhoea provided outbreak signals at an early stage, weeks and months in advance, respectively, potentially serving the purpose of early event detection. In conclusion, telephone triage data provided the most promising source for surveillance of point-source outbreaks.

Web query-based surveillance in Sweden during the influenza A(H1N1)2009 pandemic, April 2009 to February 2010.

At the Swedish Institute for Communicable Disease Control, statistical models based on queries submitted to a Swedish medical website are used as a complement to the regular influenza surveillance. The models have previously been shown to perform well for seasonal influenza. The purpose of the present study was to evaluate the performance of the statistical models in the context of the influenza A(H1N1)2009 pandemic, a period when many factors, for example the media, could have influenced people's search behaviour on the Internet and consequently the performance of the models. Our evaluation indicates consistent good reliability for the statistical models also during the pandemic. When compared to Google Flu Trends for Sweden, they were at least equivalent in terms of estimating the influenza activity, and even seemed to be more precise in estimating the peak incidence of the influenza pandemic.

Practical usage of computer-supported outbreak detection in five European countries.

This paper discusses computer-supported outbreak detection using routine surveillance data, as implemented at six institutes for infectious disease control in five European countries. We give an overview of the systems used at the Statens Serum Institut (Denmark), Health Protection Agency (England, Wales and Northern Ireland), Robert Koch Institute (Germany), Governmental Institute of Public Health of Lower Saxony (Germany), National Institute for Public Health and the Environment (the Netherlands) and Swedish Institute for Infectious Disease Control (Sweden). Despite the usefulness of the algorithms or the outbreak detection procedure itself, all institutes have experienced certain limitations of the systems. The paper therefore concludes with a list of recommendations for institutes planning to introduce computer-supported outbreak detection, based on experiences on the practical usage of the systems. This list--which concerns usability, standard operating procedures and evaluation--might also inspire improvements of systems in use today.

Ultrastructural studies on the effect of transforming growth factor-beta 1 on rat articular cartilage.

The destruction of articular cartilage in degenerative and inflammatory joint disease reflects an imbalance between synthesis and degradation of the structural components of the tissue. In previous, mainly in vitro studies, TGF-beta has been shown not only to play a role in controlling the synthesis of matrix components such as collagen and proteoglycans but also to influence their degradation. To elucidate the effect of local administration of TGF-beta on unloaded articular cartilage in growing rats, three animals were given intraarticular injections of TGF-beta for three consecutive days and sacrificed on the fourth. Perfusion fixation was combined with qualitative and quantitative evaluation (stereology) both at the light and electron microscopic level. Local administration of TGF-beta resulted in a decrease in height of the hypertrophic zone. Furthermore, the volume density of cells decreased and cells with a distinct morphology designated stellate cells appeared in this zone. In the same compartment, TGF-beta administration resulted in decreased pericellular collagen volume density while the volume density increased in the intermediate zone. The results of our investigation support and extend previous observations: TGF-beta does not only modulate the metabolism of articular cartilage in general, but the effect is targeted to specific subcompartments of the matrix. However, the result of this acute effect on the long-term function of the tissue remains to be elucidated.

Effect of transforming growth factor-beta and platelet-derived growth factor-BB on articular cartilage in rats.

The short-term and long-term effects on the growth zone in articular cartilage of transforming growth factor-beta 1 and platelet-derived growth factor-BB injected intraarticularly into the knee joint of growing rats were investigated. The changes induced by five injections of 0.5 micrograms of transforming growth factor-beta 1 included a rapid decrease in the size and number of hypertrophic cells and an enhanced subchondral bone formation. The changes were most marked in the patella but were also apparent in the tibia and femur. The proliferating cells became swollen and lost their normal organization. From the seventh day of the experiment to about 3 weeks, the matrix stained intensely with safranin O for proteoglycans. The alterations induced by transforming growth factor-beta also included synovial fibroplasia and synovitis, consisting predominantly of mononuclear cells. Localised necroses in the cartilage sometimes appeared after 21 days. In long-term studies, destroyed cartilage was found in three of six rats and partial ossification of the joint cartilage was found in two after 90 and 180 days. Ossicles developed in the tendons in all six patellae. Injection of platelet-derived growth factor-BB resulted in an early and transitory minor increase in the osteogenic activity in the zone between cartilage and red bone marrow and later produced an ossicle in one of four tendons. None of the other changes noted after injection of transforming growth factor was observed.

Osteoarthrosis and late growth.

To examine the hypothesis that late growth of bone may occur, pelvic radiographs taken during 1990 to 1992 of patients born between 1901 and 1972 were studied. All radiographs were taken using the same equipment with constant exposure techniques. Films showing osteoarthrosis (obviously decreased joint space) or hip fracture were discarded. The remaining films of 116 women and 100 men divided into 3 age groups (18-39 years old, 40-59 years old, and > 60 years old) were measured. With a millimeter ruler and a circle template, the center and 5 radii of each femoral head, the width of the acetabulum, and the pelvic diameters, the femoral neck, and the height of the superior joint space were determined. Most of the measurements increased significantly with age, including those of the femoral head, the acetabulum, the femoral neck in women, and the pelvic diameters. The increase in superior joint space (the combined heights of the cartilage of the femoral head and acetabulum) with age was not significant, but in men between 50 and 70 years old there were cartilage measurements that were higher than in other age groups, and in women > 80 years of age there were significantly more single high values. The results are discussed against the background that growth of bone and of cartilage can hypothetically cause injuries of the cartilage.

Sequential appearance of macromolecules in bone induction in the rat.

The appearance of noncollagenous proteins and proteoglycans during induction of cartilage and bone by implanted demineralized bone powder was studied by immunohistochemistry with polyclonal antibodies. Three bone proteins (osteopontin, sialoprotein, and a 62 kDa protein) were present in the bone powder grains before implantation. They appeared to be lost slowly from the granulation tissue but reappeared when bone formation started. The raw powder also contained a cartilage protein, biglycan (S1), chondrocalcin, cartilage oligomeric matrix protein, and the large proteoglycan aggrecan. The amounts of these molecules, however, increased significantly both within and outside the grains on cartilage formation. Cartilage matrix protein (148 kDa protein) appeared sparsely. The 58 kDa protein and fibromodulin (59 kDa protein), particularly the latter, were prevalent in fibrillar bundles. Antibodies against the laminin-staining vessel basement membranes showed an abundant occurrence of capillaries within the matrix grains in the granulation tissue and in the precartilaginous tissue. Bone powder made noninductive by 4 M guanidine HCl did not induce cartilage and did not stain for antibodies against bone proteins or for molecules restricted to cartilage.

Does osteoarthrosis depend on growth of the mineralized layer of cartilage?

Osteoarthrosis (OA) cannot be adequately studied in exclusively biologic-biochemical terms or exclusively mechanical terms. A common but unproven theory states that OA is primarily a degenerative disease of the cartilage with secondary bone changes. However, there are reasons to believe that primary OA is actually a disorder of the entire joint end, consisting of a reactivation of growth factors in the mineralized part of the joint cartilage (remnants of the growth cartilage of the joint head in childhood). Some growth occurs normally in loaded joints in elderly people. When the joint head expands, the cartilage is mechanically injured by stiffness gradients or impaired nutrition. Attempts to heal the wounds and phagocytosis of detritus release cytokines, enzymes, and additional growth factors within the joint cavity. The released factors in the joint, together with the continuous loading, produce all the typical osteoarthritic changes in cartilage, subchondral bone, and the joint capsule, with stasis and increased bone marrow pressure.

The occurrence of accessory immunologic cells in bone induction.

The differentiating tissues in fracture healing and in demineralized bone-powder-induced (DBP) bone formation were investigated with monoclonal antibodies with respect to the occurrence of Ia-positive cells, macrophages, and lymphocytes with interleukin-2 receptors (IL-2). Ia refers to molecules on the cell surface belonging to Class II of the major histocompatibility complex and is specific for the species and the individual. In both types of granulation tissues (fracture healing and following DBP implantation), the mesenchymal cells from the surrounding musculature were accompanied by large numbers of Ia-positive cells and common macrophages. The occurrence of IL-2 receptors was sparse in fracture healing but rich in DBP induction, probably because of its immunogenic properties, though weak. On Day 7, almost all existing cells in DBP induction were Ia-positive, signifying an immunologic effector phase apparently directed to the remaining still-passive bone powder in the periphery, while the central part of the inserted bone powder was producing cartilaginous cells and matrix. The presence of accessory immunologic cells in fracture healing is perhaps due to a surveillance function (a standard response on injury), but the cell differentiation might also be dependent on the active mediators emitted from Ia-positive cells and macrophages. This investigation strengthens the concept that induced bone development occurs in experimental fracture healing.

Demonstration of blood-vessellike structures in cartilaginous callus by antilaminin and antiheparin sulfate proteoglycan antibodies.

The vascularization of the callus of experimental nonfixated tibia fractures in rat was investigated with antibodies against two basement-membrane macromolecules, i.e., laminin and the heparin sulfate, low-buoyant-density proteoglycan. The purpose of the investigation was to study the relationship between the appearance of blood vessels and the development of cartilaginous callus. The ages of the callus were three, five, eight, and 11 days after the fracture, that is, from before the cartilage was demonstrable on Day 5 until the enchondral bone formation started on Day 11. The abundant blood vessels in the differentiating granulation tissue, in the periosteal callus, and in the cortical bone itself were stained, as were the endomysia of the surrounding myofibrils. During the whole course, the cartilaginous callus also contained vessellike structures stained by the antibodies. These structures are apparently nonfunctioning vessels. Also, some of the chondrocytes were stained by antilaminin. This study implies that cartilage is not formed as a result of insufficient blood supply, but rather as a natural link in a predetermined course of the migrating mesenchymal cells.

Current concepts of fracture healing.

The current concepts of fracture healing are mainly based on two variables: blood supply and stability. The effect of electricity on delayed union has not been explained. Possible individual differences in the primary osteogenetic activity and the effect of soft-tissue injuries are seldom considered. In recent years, interesting data have revealed how biomechanical forces and electric currents can be translated to biochemical mediators such as prostaglandins (PGE2), morphogens, and growth factors. It is likely that the fracture ends emit osteogenic signal substances (such as bone morphogenetic protein) to the exudate in addition to those mediators (interleukin-1, growth factors) which are released from the blood clot as in wound healing. Movement of the fragments increases the fracture exudate with its migrating cells and sprouting vessels, resulting in exuberant callus. Cartilage is formed in the well-vascularized granulation tissue due to its ability to repel vessels. Rigid fixation minimizes granulation tissue and external callus. Rigid plates may also retard effusion of morphogens and growth factors from bone ends. Reaming of the intramedullary canal and nailing may cause additional bone damage, which may increase the osteogenetic activity. Weight bearing stimulates growth factors and PGE2. The molecular activity of the fracture exudate is the most decisive factor for bone healing. This activity can be impeded by diastasis, infections, and soft-tissue crushing injuries that cause extensive activation of macrophages and activate mediators, disturbing the osteogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

The implantation of demineralized fracture matrix yields more new bone formation than does intact matrix.

The inductive capacity of demineralized/lyophilized bone matrix prepared from fractured tibia ends in rats at different intervals after fracture was compared with matrix from the opposite, intact tibia. Fracture matrix and normal matrix cut in longitudinal strips were implanted in the gluteal muscles of 47 rats and were harvested after 15, 30, and 50 days. Staining was performed with hematoxylin-eosin, toluidine blue, and by monoclonal antibodies against Ia-antigen and collagen II. In comparison to the normal matrix, the fracture matrix brought about a more rapid bone formation counted as mineralization after 30 days and formation of ossicles after 30 and 50 days. Matrix from eight-day-old fracture was the most potent inductor compared to matrix from the other post-fracture intervals (one, five, and 11 days). Typical for the responding cells surrounding the implanted matrix was the abundant occurrence of cells carrying Ia-antigen. The cells penetrating the matrix formed pseudopods and could therefore be characterized as dendritic cells. The higher inductive capacity of fracture matrix might have some importance for the formation of the inductive enchondral callus in normal fracture healing.