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Background: Recent evidence suggests that there may be an increased risk of infection for patients undergoing a corticosteroid injection before, during, or after knee arthroscopy. Purpose: To systematically review the literature to evaluate the risk of postoperative infection in patients undergoing intra-articular corticosteroid injections (CSI) before, during, or after knee arthroscopy. Study Design: Systematic review; Level of evidence, 3. Methods: A systematic review was performed by searching the PubMed, Cochrane Library, and Embase databases to identify studies that evaluated the rate of postoperative infection in patients undergoing knee arthroscopy who received an intra-articular CSI during the perioperative period. The search phrase used was “knee AND arthroscopy AND injection AND (infection OR revision).” A subanalysis was also performed to analyze infection rates based on the timing of the corticosteroid injection in relation to arthroscopy. Results: Four studies met the inclusion criteria, representing 11,925 patients undergoing knee arthroscopy with an intra-articular CSI administered during the perioperative period (mean follow-up, 5.3 months) and 247,329 patients without a corticosteroid injection during the perioperative period (mean follow-up, 5.9 months). Patients who received an injection experienced a statistically significantly higher rate of postoperative infection (2.2%) when compared with patients who did not receive an injection (1.1%; P < .001). When analyzed by the timing of the injection, patients receiving an injection preoperatively or intraoperatively experienced a statistically significantly higher rate of postoperative infection (3% and 2.6%, respectively) when compared with patients receiving an injection postoperatively (1.4%; P = .001 for both). Conclusion: Patients undergoing knee arthroscopy who receive an intra-articular CSI during the perioperative period can be expected to experience significantly higher postoperative infection rates when compared with patients not receiving an injection. Furthermore, patients receiving a corticosteroid injection pre- or intraoperatively may experience significantly higher rates of postoperative infection when compared with patients receiving an injection postoperatively.

To assess the impact of mammography capacity on appointment wait times.We surveyed by telephone all mammography facilities federally certified in 2008 in California, Connecticut, Georgia, Iowa, New Mexico, and New York using a simulated patient format. County-level mammography capacity, defined as the number of mammography machines per 10,000 women aged 40 and older, was estimated from FDA facility certification records and US Census data.1,614 (86%) of 1,882 mammography facilities completed the survey. Time until next available screening mammogram appointment was1 week at 55% of facilities, 1-4 weeks at 34% of facilities, and1 month at 11% of facilities. Facilities in counties with lower capacity had longer wait times, and a one-unit increase in county capacity was associated with 21% lower odds of a facility reporting a wait time1 month (p0.01). There was no association between wait time and the availability of evening or weekend appointments or digital mammography.Lower mammography capacity is associated with longer wait times for screening mammograms.Enhancement of mammography resources in areas with limited capacity may reduce wait times for screening mammogram appointments, thereby increasing access to services and rates of breast cancer screening.

The objective of our study was to assess the experiences and preferences of radiology residents with respect to breast imaging.We surveyed radiology residents at 26 programs in New York and New Jersey. Survey topics included plans for subspecialty training, beliefs, and attitudes toward breast imaging and breast cancer screening and the likelihood of interpreting mammography in the future.Three hundred forty-four residents completed the survey (response rate, 62%). The length of time spent training in breast imaging varied from no dedicated time (37%) to 1-8 weeks (40%) to more than 9 weeks (23%). Most respondents (97%) agreed that mammography is important to women's health. More than 85% of residents believed that mammography should be interpreted by breast imaging specialists. Respondents shared negative views about mammography, agreeing with statements that the field was associated with a high risk of malpractice (99%), stress (94%), and low reimbursement (68%). Respondents endorsed several positive attributes of mammography, including job availability (97%), flexible work schedules (94%), and few calls or emergencies (93%). Most radiology residents (93%) said that they were likely to pursue subspecialty training, and 7% expressed interest in breast imaging fellowships.Radiology residents' negative and positive views about mammography seem to be independent of time spent training in mammography and of future plans to pursue fellowship training in breast imaging. Systematic assessment of the plans and preferences of radiology residents can facilitate the development of strategies to attract trainees to careers in breast imaging.

Screening mammography rates vary geographically and have recently declined. Inadequate mammography resources in some areas may impair access to this technology. We assessed the relationship between availability of mammography machines and the use of screening.The location and number of all mammography machines in the United States were identified from US Food and Drug Administration records of certified facilities. Inadequate capacity was defined as1.2 mammography machines per 10,000 women age 40 or older, the threshold required to meet the Healthy People 2010 target screening rate. The impact of capacity on utilization was evaluated in 2 cohorts: female respondents age 40 or older to the 2006 Behavioral Risk Factor Surveillance System survey (BRFSS) and a 5% nationwide sample of female Medicare beneficiaries age 65 or older in 2004-2005.About 9% of women in the BRFSS cohort and 13% of women in the Medicare cohort lived in counties with1.2 mammography machines per 10,000 women age 40 or older. In both cohorts, residence in a county with inadequate mammography capacity was associated with lower odds of a recent mammogram (adjusted odds ratio in BRFSS: 0.89, 95% CI: 0.80-0.98, P0.05; adjusted odds ratio in Medicare: 0.86, 95% CI: 0.85-0.87, P0.05), controlling for demographic and health care characteristics.In counties with few or no mammography machines, limited availability of imaging resources may be a barrier to screening. Efforts to increase the number of machines in low-capacity areas may improve mammography rates and reduce geographic disparities in breast cancer screening.

Objective. We investigate the causes of the stability of Swedish business confidence in the early 1930s. Surprisingly, investors seemed unruffled by the Social Democrats’ heterodox “Crisis Program,” a proto-Keynesian response to the Great Depression. This research allows a productive modification of the argument that the state is dependent on private capital formation. Methods. Analysis of stock markets, currency prices, patterns of domestic investment, as well as written primary sources in Swedish and English. Results. The cross-class cooperation practiced by the Social Democrats, and the lack of a threat of radicalization, had an important calming effect on investors. Conclusions. To avoid capital flight and resulting economic dislocation, reformist governments must cooperate with business and conservatives, and turn away from workers and revolutionaries.

A subfossil fragment of the deep-sea gorgonian coral Primnoa resedaeformis was 14C AMS dated along a radial growth transect. Dates ranged from 2600±50 at the outside, to 2920±60 14C years BP near the interior, suggesting an age of

Using a model recombinant retrovirus encoding the Escherichia coli lacZ gene, we have found that medium conditioned with NIH 3T3 cells and packaging cell lines derived from NIH 3T3 cells inhibits infection. Most of the inhibitory activity was greater than 100 kDa and was sensitive to chondroitinase ABC digestion, which is consistent with the inhibitor being a chondroitin sulfate proteoglycan. Proteoglycans secreted by NIH 3T3 cells and purified by anion-exchange chromatography inhibited amphotropic retrovirus infection. Pretreatment of amphotropic retrovirus stocks with chondroitinase ABC boosted the level of transduction efficiency by more than twofold. The implications of these findings with respect to retrovirus-cell interactions and the production of high-titer retroviral stocks are discussed.

Background. During cardiopulmonary bypass anasopharyngeal temperature greater than 38°C at the end of rewarming may indicate cerebral hyperthermia. This could exacerbate an ischemic brain injury incurred during cardiopulmonary bypass. Methods. In a cohort of 150 aortocoronay bypass patients neuropsychologic test scores of 66 patients whose rewarming temperature exceeded 38°C were compared with those who did not. There were no differences between groups with respect to demographic and intraoperative variables. Results. A trend was seen for hyperthermic patients to do worse on all neuropsychologic tests in the early postoperative period but not at 3-month follow-up. By analysis of covariance hyperthermic patients did worse on the visual reproduction subtest of the Weschler memory scale at 3 months ( p = 0.02), but this difference was not found by linear regression ( p = 0.10). Conclusions. We were unable to demonstrate any significant deterioration in patients rewarmed to greater than 38°C in the early postoperative period. The poorer performance in the visual reproduction subtest of the Wechsler memory scale at 3 months in the group rewarmed to more than 38°C is interesting but far from conclusive. Caution with rewarming is still advised pending more in-depth study of this issue.

BACKGROUND: Patient navigation can increase colorectal cancer screening rates. The net economic impact of a colonoscopy patient navigator program was evaluated in an urban public hospital setting. METHODS: Cost, cost-effectiveness, and cost-benefit analyses were performed of a colonoscopy patient navigation program at 3 urban public hospitals in the period from 2003 to 2007. Program effectiveness was assessed in a 2-group, pre- and post-program, nonrandomized evaluation, comparing program hospitals with comparison hospitals that served similar populations. Costs were assessed from the provider's perspective. Outcomes included colonoscopy volume, colonoscopy completion rate, program cost, incremental cost-effectiveness, and net monetary benefit. RESULTS: Patient navigation was associated with a 61% increase in average monthly colonoscopy volume at program hospitals, from 114 procedures to 184 procedures, compared with a 12% increase at comparison hospitals. Adjusted for other factors, the navigator program increased colonoscopy volume by 44 to 67 additional procedures per month. Average program cost varied from $50 to $300 per patient referred to a navigator. Incremental cost-effectiveness varied from $200 to $700 per additional colonoscopy. At 2 hospitals, net revenue associated with increased colonoscopy volume exceeded the program cost per additional colonoscopy, yielding a net financial benefit; at the third hospital, the program yielded a net cost. Variation between hospitals in the program's economic impact was primarily attributable to differences in personnel costs. CONCLUSIONS: Economic evaluation of this colonoscopy patient navigator program in an urban public hospital setting suggests that such programs can be a cost-effective use of limited resources and yield a net financial benefit for providers. Cancer 2012. © 2012 American Cancer Society.

It is often felt that poorly controlled epileptic patients, who are taking anticonvulsant medication, are over represented in A&E departments compared to the general population. This A&E based study set out to determine whether such patients do have inadequate serum anticonvulsant levels, when they present following a seizure, to A&E departments. All epileptic patients, taking medication, who presented to the A&E departments of St. Bartholomew's and Hackney Hospitals, London, over a 4-month period were studied. Serum anticonvulsant concentrations were measured on their arrival in the departments. Forty-six patients were studied. Only 21% of anticonvulsant drug concentrations were within 'therapeutic' ranges. A total of 66% were below 'therapeutic' ranges and 13% were potentially toxic. The implication of these findings is discussed.

We performed two semen analyses in each of a small cohort of 11 GH-deficient (GHD) adolescents (mean age 18.1 +/- 0.6 yrs), previously treated (mean 29 months prior) with either GH alone or GH and an aromatase inhibitor (anastrozole) for 12 months and compared their data with those of 10 healthy controls (mean age 18.7 +/- 1.8 yrs). Although some adolescents had lower sperm parameters as compared to adult reference values, mean sperm concentrations, motility, and morphology were comparable among the 3 groups, suggestive that this small group of GHD adolescents previously treated with anastrozole has descriptively similar sperm parameters as other GHD and GH-sufficient adolescent controls.

A field thermal test was conducted by the Yucca Mountain Site Characterization Project to observe changes in the Topopah Spring Tuff middle nonlithophysal zone geohydrologic system due to thermal loading. A laboratory-scale crushed-tuff hydrothermal column test was used to investigate the tuff as a potential construction material within a nuclear-waste repository. Results of similar column tests have been cited as indications that silica deposition would plug the rock fractures above a repository and create unfavorable drainage conditions. Data from field and laboratory tests are used here to predict the magnitude of fracture sealing. For the crushed-tuff column test, a one-meter-high column was packed with crushed tuff to a porosity of about 50%. Water filling the lowermost 10 cm of the column was boiled and the vapor condensed at the top of the column, percolating down to the boiling zone. After 100 days, intergranular pore space in the saturated portion of the column was almost filled with amorphous silica. The Drift Scale Test at Yucca Mountain is a heating test in the unsaturated zone. It consists of a four-year heating phase, now complete, followed by a four-year cooling phase. Heaters in a 60-m-long drift and in the adjacent rock have heatedmore » the drift walls to 200 C. As the rock was heated, fluids naturally present in the rock migrated away from the heat sources. A boiling zone now separates an inner dry-out zone from an outer condensation zone. A heat-pipe region exists in the outer margin of the boiling zone above the heated drift. Amorphous silica coatings up to a few micrometers thick were deposited in this region. Deposits were observed in less than 10% of the fractures in the heat pipe region. Drift-scale test results yield a silica deposition rate of about 250 {micro}m/1000 years in 10% of the fractures in the heat-pipe region. We did not calculate deposition rates from our column test, but a rate of 9.1 mm/1000 years in all fractures of the heat-pipe region is predicted by Sun and Rimstidt (2002) from the results of a similar test. We believe the rate based on field-test observations is a better prediction because the field test more closely resembles the expected environment in a repository. Rates based on column-test results may be reasonable for local zones of preferred fluid flow.« less

Background Alzheimer disease (AD) and vascular dementia are among the most frequently occurring causes of dementia in the world, and their accurate differentiation is important because different pharmaceutical strategies may modify the course of each disease. Objective To determine which of 10 neuropsychological test scores can accurately differentiate patients with probable AD from those with subcortical ischemic vascular dementia (SIVD) for use in evidence-based clinical practice. Design Patients with suspected dementia were referred to the study by family physicians, geriatricians, and neurologists. All participants received a thorough assessment according to standard diagnostic guidelines. Diagnoses of probable AD (n = 31) and probable SIVD (n = 31) were made according to consensus criteria. The diagnosticians were blind to the results of the 10 neuropsychological test scores. Results There were no significant differences between the groups in age or Mini-Mental State Examination scores. Logistic regression analyses identified 2 neuropsychological tests that best distinguished the groups (sensitivity = 81%; specificity = 84%; positive likelihood ratio = 5.1). These were the recognition memory subtest of the Rey Auditory Verbal Learning Test and the Controlled Oral Word Association Test. The AD group performed better on the oral association test, whereas the SIVD group did better on the recognition memory test. Conclusion Patients with probable AD and probable SIVD can be distinguished with a high degree of accuracy using these 2 neuropsychological tests.

SUMMARY The goal of this study was to examine the changes in lymphocyte populations in rectal mucosa during HIV infection and to study their relationship to mucosal immunity and to systemic depletion of CD4 lymphocytes. Rectal biopsies from 58 HIV-infected subjects and eight controls were studied. Frozen rectal tissue sections were stained with antibodies to CD4, CD3, CD8, and markers for macrophages. HIV-infected subjects were divided into early stage (no opportunistic infections) and AIDS groups. There was profound depletion of rectal lamina propria CD4 lymphocytes (16% and 6% of normal content in early and AIDS groups, respectively). However, lymphoid aggregate CD4 lymphocytes were far less severely depleted (69% and 40% of normal content, respectively). The extent of lymphoid aggregate CD4 lymphocyte depletion generally parallelled the CD4 lymphocyte depletion in the blood. CD8 lymphocyte content in both the lamina propria and lymphoid aggregates usually were increased, particularly in early-stage patients. Macrophage contents were usually normal in the HIV-infected groups. We conclude that rectal lamina propria and lymphoid aggregates are distinct compartments differing markedly in their CD4 lymphocyte content during HIV infection. In light of this and an increased number of apoptotic cells which were noted in rectal lamina propria in HIV-infected subjects, we hypothesize that intestinal lamina propria could be a site of rapid CD4 lymphocyte destruction during HIV infection.

Somatomedin C/insulin-like growth factor-I (IGF-I) is required for the proliferation of keratinocytes in vitro. In skin, the cells known to synthesize IGF-I are melanocytes and fibroblasts of the dermis. To investigate the role of IGF-I as a mediator of keratinocyte proliferation, we have used retroviral-mediated gene transfer to introduce the gene encoding human IGF-I into diploid human keratinocytes, thus causing these cells to produce a growth factor they normally do not express. Modified cells synthesized and secreted significant levels of IGF-I (560 ng/10(7) cells/24 h) in vitro. Cells expressing IGF-I were no longer dependent on exogenously added IGF-I or insulin for their sustained growth in vitro under serum-free conditions. The growth of these cells did require added epidermal growth factor (EGF) and bovine pituitary extract. The addition of an antibody that neutralizes IGF-I inhibited cell growth, suggesting that IGF-I must be secreted by the cells to promote cell proliferation. To investigate the role of IGF-I in vivo, we grafted modified keratinocytes expressing IGF-I onto athymic mice. Grafts of epithelial sheets of modified cells formed a stratified epithelium comparable to control grafts of unmodified cells. When analyzed for keratin 16 expression and by quantitative staining for the nuclear proliferation antigen Ki-67, however, modified epithelia showed an increase in these markers of proliferation when compared with grafts of unmodified cells. This study demonstrates that genetic modification can be used to modify the autocrine control of keratinocyte proliferation. The de novo synthesis of IGF-I by keratinocytes could sustain keratinocytes growth in vitro and stimulate proliferation in vivo without significantly altering epidermal differentiation. These data further support the role of IGF-I as a paracrine mediator of epidermal proliferation and as a potential signal of mesenchymal-epithelial interactions.

Using a model amphotropic recombinant retrovirus encoding the Escherichia coli lacZ gene and quantitative assays to measure virus infection, we have determined the effects of time and target cell number on infectivity. Infection of various numbers of NIH 3T3 fibroblasts showed that the extent of lacZ virus infection was dependent on virus concentration and independent of target cell number. These results demonstrate that multiplicity of infection is not an accurate predictor of the efficiency of retroviral infection. Varying the time of viral infection revealed that maximal infection occurred after greater than 24 h of exposure of the cells to the lacZ virus. Half-maximal infection occurred after 5 h of exposure. After 2 h of adsorption at 37 degrees C, the majority of infectious virus was not adsorbed to cells but was unbound and able to infect other cells. These results are discussed in terms of both their relevance to the fundamental biology of retrovirus infection and the use of recombinant retroviruses for retrovirus-mediated gene transfer with purposes of gene therapy.

Neurological injury is an important cause of morbidity and mortality after cardiac surgery. With the advent of warm heart surgery, the neuroprotective role of hypothermic cardiopulmonary bypass (CPB) has come under increasing scrutiny. Preliminary work by us in the area found no increased risk of neurological morbidity with normothermic CPB in a small group of patients and suggested a possible benefit. The purpose of the present study is to compare the incidence of neurological and neuropsychological dysfunction in a larger number of patients randomized to warm or cold aortocoronary bypass surgery.With the approval of the institutional research ethics committee, 201 aortocoronary bypass patients were randomized to normothermic or moderate hypothermic CPB and subjected to neurological and neuropsychological evaluation. These subjects were a subset of patients enrolled in a large multicenter trial comparing warm versus cold heart surgery. The examinations took place preoperatively, 5 days after operation, and a 3-month follow-up. The examination consisted of a clinical neurological examination and a brief neuropsychological test battery. The neuropsychological tests included the Buschke selective reminding procedure, the Wechsler memory scale-revised visual reproduction subtest, the trial making test (parts A and B), the Wechsler adult intelligence scale-revised digit symbol subtest, and the grooved pegboard test. The examiner and subjects were unaware of the CPB temperature allocation (warm,34 degrees C; cold,or = 28 degrees C). Statistical analysis was performed using the SAS statistical software package. Two hundred one patients were enrolled in the study. Of these, 155 patients completed the entire protocol and were included in the final analysis (warm group, n = 78; cold group, n = 77). One patient in the warm group died perioperatively from a massive hemispheric stroke. Another warm group patient was unable to complete neuropsychological evaluation because of a perioperative stroke. Thus, 153 patients completed the entire series of neuropsychological tests. A total of 6 patients (warm group, n = 2; cold group, n = 4; P = NS) suffered from perioperative focal neurological deficits. There was a consistent deterioration in scores from tests of psychomotor speed/coordination (trial making, digit symbol, pegboard) in the early postoperative period, which resolved by the 3-month follow-up. Tests of memory (Buschke, Wechsler memory scale) showed no evidence of patient deterioration in the postoperative period. No difference was seen between the warm and cold groups.In this randomized trial of normothermic versus hypothermic CPB, we found deterioration in scores of tests of psychomotor speed but not of memory in the early postoperative period. We were unable to demonstrate any neuroprotective effect from moderate hypothermia in this patient population.

Natural rock-forming minerals and many synthetic materials have traditionally been characterized by electron microprobe analysis (EMPA). However, recent advances in technology have created attractive alternatives to EMPA that focus instead on bulk chemistry and high-resolution surface studies. The purpose of this abstract is to demonstrate the continued usefulness of careful electron microprobe analysis as part of a well-coordinated analytical study. To this end, a brief summary is presented of the role the electron microprobe played in the recent discovery of yoshiokaite, a new Ca, Al-silicate mineral and one of only three new minerals discovered on the Moon.[l]Regolith breccias returned by several Apollo missions were subjected to extensive bulk chemical studies at the University of California, Los A n geles.[2] These bulk chemical studies focused particularly on key trace elements that might identify exotic regolith breccias.

This research report analyzes the evolution of the bond between a charismatic leader and his mass following. Its empirical focus is the case of Juan Peron and the Peronist movement in Argentina. After discussing stages in the evolution of charisma, we review our earlier findings showing that by 1965 there was clear separation between those Peronists devoted to the movement and those Peronists devoted to the man. We note distinctive features in the social and attitudinal profiles of each and then turn to our principal concern, the recruitment of new blood into each Peronist camp. Personalist youth turn out to be much like their older counterparts, but organizationalist youth demonstrate social and attitudinal features that set them dramatically apart from the personalists and apart from the older organizationalists as well. We discuss the implications of this ever widening rift.

Students of Latin American political parties have long assumed a strong correlation between social class and party identification, yet this assumption has never been tested empirically in any of the Latin American nations. This is probably due in large part to the lack of reliable survey data; however, even the mass of aggregate voting data has seldom been analyzed systematically. As a result, most of what we know—or think we know—about voting behavior in Latin America is based upon the intuitive assumptions of North American scholars. “If I were a member of the Chilean middle class, I would probably vote for the Radicals or Christian Democrats, but on the other hand if I were quite wealthy I would probably vote for the Conservatives.”Students of Argentine politics assume that the Conservative parties, always representing the interests of the nation's aristocracy, have received the bulk of their votes from the large landowners; that the interests of this group consistently have been opposed by the Radical parties who receive their electoral support from the urban middle classes; and that the more recently formed Peronist parties have championed the cause of, and been supported at the polls by, the industrial workers. It is the purpose of this article to test these assumptions, primarily through analysis of aggregate voting data, but also by examining the social backgrounds of party leaders and their actions while in power.

Seeds of loblolly pine, Pinus taeda L., and of white pine, P. strobtus L., which require a long moist treatment at a low temperature (stratification) for complete germination, were chosen for this study. Seeds of the former species require 30 to 90 days at 2 to 3 C and those of the latter 30 days at 10 C or 60 days at 4 C (27). The purpose of the work was to investigate responses of these seeds to red and far-red radiation, which controls germination (4) through the phytochrome pigment (13). Phytochrome exists in two interconvertible forms (4). The P660 form absorbs red light and is converted to the P730 form believed to be active biologically. The P730 form absorbs far red and is converted to the inactive P660 form. The P730 form also reverts in darkness to the P660 form (13). Most seeds in which the action of phvtochrome has been demonstrated germinate promptly and completely after one brief exposure to light (23). A few seeds in a sample of seed of Virginia pine, P. virginiana Mill., also germinate in response to a single brief irradiation, but most of them require a short period at a low temperature before they germinate in response to light (26). This change in light requirement of Virginia pine seeds after a short period at a low temperature made it important to measure similar changes in loblolly and white pine seeds, which reportedly require appreciable stratification.

The responses to light of lettuce and Lepidium seeds depend on the reversible red, far-red photoreaction (3,5). These light-sensitive seeds are rather small in comparison with seeds of several species of southern pines reported by Nelson (4) to be stimulated to germinate by light. The current experiments were conducted to determine whether seeds of Pinus virginiana respond to the reversible red, far-red photoreaction in the same way as lettuce and Lepidiunm seeds, and how the responses are modified by temperature and condition of imbibition.

The age-old turpentine industry is being modernized by a three-fold research attack involving advances in extraction techniques through chemical stimulation procedures; the selection, breeding and propagation of high-yielding turpentine pines; and engineering research on equipment used in woods operations.

The Peronist victories in the 1962 elections, the subsequent military coup, and the nationalistic platform of the President elected in 1963 have again focused attention on the Argentine political scene. Much has been written about these and other aspects of contemporary Argentine politics; however, one major factor that has been almost completely ignored is the split within Argentine Radicalism that produced two separate Radical Parties. This article attempts to point out some of the reasons for the formation of these parties and also to trace their evolution through July, 1963.The 1957 split was not the first to occur within theUnión Cívica Radical(Radical Civic Union or UCR); in fact the party was born of the 1891 split of the Civic Union into Nationals and Radicals. Although the UCR had definite internal factions as early as 1897, the first real split in the party came in 1922, when many Radicals left to form the Anti-personalist UCR under the leadership of President Marcelo T. Alvear.

We investigated the hypothesis that keratinocyte-produced platelet-derived growth factor-AA (PDGF-AA) is involved in epidermal-dermal interactions and that PDGF-AA is an important mediator of the temporal and spatial events of tissue repair. Retroviral-mediated gene transfer was used to introduce the gene encoding human PDGF-A into cultures of human diploid keratinocytes. Genetic modification boosted the endogenous in vitro level of PDGF-AA secretion by over 300 fold. When PDGF-secreting cells were transplanted as epithelial sheets to athymic mice, modified keratinocytes underwent terminal differentiation and generated a stratified epithelium comparable to unmodified cells. Seven days after grafting the newly synthesized connective tissue layer subjacent to the PDGF-A-modified grafts was significantly thicker, was rich in mononuclear cells and fibroblasts, and had increased numbers of blood vessels when compared to control grafts of unmodified cells. These results suggest that PDGF-AA secreted by the epidermis is an important mediator of epithelial-mesenchymal interactions and helps to promote growth and vascularization of the underlying dermal tissue. Further, these data demonstrate the feasibility of using genetically modified cells to modulate tissue regeneration.

A series of hyperkinetic children (Minimal Brain Dysfunction) is presented, who in part or whole responded to therapy for chronic constipation.

This study provides demographic and medical information about patients admitted with head injuries to Sunnybrook Medical Centre, Toronto, Ont., in 1978 and in 1982. Data are presented about patient age and sex, type and cause of accident, length of stay, extracranial complications, severity of head injury, frequency of use of various neurodiagnostic techniques and type of discharge placement. The costs of hospitalization for such patients, both in the Sunnybrook Medical Centre and for Canada as a whole, are estimated.

The alleged beneficial effect of selenium (Se) on fibromuscular rheumatism in residents of low soil-Se areas of New Zealand has been explored. Three dosing trials, two of them double blind trials, using physiological daily supplements (100 micrograms Se) of sodium selenite or selenomethionine and a placebo have been carried out. Blood Se and glutathione peroxidase (EC 1.11.1.9; GSHPX) activities were monitored and clinical assessment of the efficacy of the treatment was made during the trials. Blood Se and GSHPX activities rose in all patients who received Se whereas those in control groups remained more or less constant throughout the study. Clinical assessment of muscular symptoms showed that approximately half of the patients in both trial groups and placebo groups responded to treatment. Thus we have been unable to give conclusive evidence of a response to Se supplementation for relief of muscular complaints.

Trees, like other plants, contain many natural chemicals of the sort that we call hormones. Research is gradually revealing that, in the behavior of a tree, these chemicals may be almost as important as the basic influences of heredity and environment.