A review and p-curve analysis of research on the menstrual cycle correlates of consumer preferences and economic decisions.

A number of studies have been claimed to show that ovarian hormones, whose levels fluctuate throughout the menstrual cycle, affect consumer preferences and financial decisions. The present article aims to critically analyze the literature examining associations between the phases of the menstrual cycle (peri-ovulatory vs. non-ovulatory) with particular consumer preferences (especially regarding clothing choices) and economic decisions (especially in regards to economic games and risk-taking). A search for studies was conducted in Web of Science and Scopus between 2004 and 2022, by combining keywords of the menstrual cycle, consumer preferences, and economic decisions. Once articles were selected, we identified the main findings, the characteristics of the population, and the methods for determining the phases of the cycle. We performed a p-curve analysis on previously reported statistically significant effects. These analyses find evidence for associations between peri-ovulatory status and specific consumer preferences, most strongly for appearance-enhancing products. They yield no compelling evidence for associations between peri-ovulatory status and financial decisions and risk-taking. We offer provisional conclusions and call for additional studies that possess sufficient statistical power to detect true meaningful effects, especially in the domain of financial decisions.

Functions of Astrocytes under Normal Conditions and after a Brain Disease.

In the central nervous system (CNS) there are a greater number of glial cells than neurons (between five and ten times more). Furthermore, they have a greater number of functions (more than eight functions). Glia comprises different types of cells, those of neural origin (astrocytes, radial glia, and oligodendroglia) and differentiated blood monocytes (microglia). During ontogeny, neurons develop earlier (at fetal day 15 in the rat) and astrocytes develop later (at fetal day 21 in the rat), which could indicate their important and crucial role in the CNS. Analysis of the phylogeny reveals that reptiles have a lower number of astrocytes compared to neurons and in humans this is reversed, as there have a greater number of astrocytes compared to neurons. These data perhaps imply that astrocytes are important and special cells, involved in many vital functions, including memory, and learning processes. In addition, astrocytes are involved in different mechanisms that protect the CNS through the production of antioxidant and anti-inflammatory proteins and they clean the extracellular environment and help neurons to communicate correctly with each other. The production of inflammatory mediators is important to prevent changes in brain homeostasis. On the contrary, excessive, or continued production appears as a characteristic element in many diseases, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and in neurodevelopmental diseases, such as bipolar disorder, schizophrenia, and autism. Furthermore, different drugs and techniques have been developed to reverse oxidative stress and/or excess of inflammation that occurs in many CNS diseases, but much remains to be investigated. This review attempts to highlight the functional relevance of astrocytes in normal and neuropathological conditions by showing the molecular and cellular mechanisms of their role in the CNS.

Family still matters: Human social motivation across 42 countries during a global pandemic.

The COVID-19 pandemic caused drastic social changes for many people, including separation from friends and coworkers, enforced close contact with family, and reductions in mobility. Here we assess the extent to which people's evolutionarily-relevant basic motivations and goals-fundamental social motives such as Affiliation and Kin Care-might have been affected. To address this question, we gathered data on fundamental social motives in 42 countries (N = 15,915) across two waves, including 19 countries (N = 10,907) for which data were gathered both before and during the pandemic (pre-pandemic wave: 32 countries, N = 8998; 3302 male, 5585 female; M age  = 24.43, SD = 7.91; mid-pandemic wave: 29 countries, N = 6917; 2249 male, 4218 female; M age  = 28.59, SD = 11.31). Samples include data collected online (e.g., Prolific, MTurk), at universities, and via community sampling. We found that Disease Avoidance motivation was substantially higher during the pandemic, and that most of the other fundamental social motives showed small, yet significant, differences across waves. Most sensibly, concern with caring for one's children was higher during the pandemic, and concerns with Mate Seeking and Status were lower. Earlier findings showing the prioritization of family motives over mating motives (and even over Disease Avoidance motives) were replicated during the pandemic. Finally, well-being remained positively associated with family-related motives and negatively associated with mating motives during the pandemic, as in the pre-pandemic samples. Our results provide further evidence for the robust primacy of family-related motivations even during this unique disruption of social life.

Stress-deprivation induces an up-regulation of versican and connexin-43 mRNA and protein synthesis and increased ADAMTS-1 production in tendon cells in situ.

Purpose: The proper function of the tenocyte network depends on cell-matrix as well as intercellular communication that is mechanosensitive. Building on the concept that the etiopathogenic stimulus for tendon degeneration is the catabolic response of tendon cells to mechanobiologic under-stimulation, we studied the pericellular matrix rich in versican and its predominant proteolytic enzyme ADAMTS-1, as well as Connexin-43 (Cx43), a major gap junction forming protein in tendons, in stress-deprived rat tail tendon fascicles (RTTfs).Materials and Methods: RTTfs were stress-deprived for up to 7 days under tissue culture conditions. RT-qPCR was used to measure mRNA expression of versican, ADAMTS-1, and Cx43. Protein synthesis was determined using Western blotting and immunohistochemistry.Results: Stress-deprivation (SD) caused a statistically significant up-regulation of versican, ADAMTS-1, and Cx43 mRNA expression that was persistent over the 7-day test period. Western blot analysis and immunohistochemical assessment of protein synthesis revealed a marked increase of the respective proteins with SD. Inhibition of proteolytic enzyme activity with ilomastat prevented the increased versican degradation and Cx43 synthesis in 3 days stress-deprived tendons when compared with non-treated, stress-deprived tendons.Conclusion: In the absence of mechanobiological signaling the immediate pericellular matrix is modulated as tendon cells up-regulate their production of ADAMTS-1, and versican with subsequent proteoglycan degradation potentially leading to cell signaling cues increasing Cx43 gap junctional protein. The results also provide further support for the hypothesis that the cellular changes associated with tendinopathy are a result of decreased mechanobiological signaling and a loss of homeostatic cytoskeletal tension.

Validation of a Minor Modification to the Soleris® Direct Yeast and Mold Vial and Selective Supplement.

Here we describe results of a study to validate minor reagent formulation changes to the Soleris Direct Yeast and Mold (DYM) automated growth-based method for semi-quantitative detection of yeast and mold in food products. In order to reduce the maximum concentration of the selective agent chloramphenicol in the Soleris reagents, chloramphenicol was removed from the selective supplement and added to the vial growth medium itself. Therefore, both the vial medium and supplement have been reformulated in an alternative version of the method. A probability of detection (POD) statistical model was used to compare Soleris results at multiple test thresholds (dilutions) with plate counts determined using the U.S. Food and Drug Administration Bacteriological Analytical Manual dilution plating procedure. Three matrixes were tested; yogurt, tomato juice, and cocoa powder. POD analysis showed that the percentage of positive Soleris tests at various test thresholds were within the limits predicted by the reference method plate counts for all matrixes evaluated. Real-time stability data on three manufactured lots showed that the modified Soleris vial and supplement are stable for at a minimum of 10 months when stored at 2-8°C. In sum, results presented here demonstrate that the modifications to the Soleris DYM vial and supplement do not impact method performance. The modified Soleris DYM method can be used as an accurate alternative to conventional dilution plating procedures for semi-quantitative determination of yeast and mold at threshold levels, while saving as much as 3 days in analysis time.

Validation of Modifications to the ANSR® Salmonella Method for Improved Ease of Use.

This paper describes the results of a study to validate minor reagent formulation and procedural changes to the ANSR® Salmonella method, AOAC Performance Tested Method™ 061203. In order to improve ease of use and diminish risk of amplicon contamination, the lyophilized reagent components were reformulated for increased solubility, thus eliminating the need to mix by pipetting. In the alternative procedure, an aliquot of the lysate is added to lyophilized ANSR reagents, immediately capped, and briefly mixed by vortex. Results of the validation study with ice cream, peanut butter, dry dog food, raw ground turkey, raw ground beef, and sponge samples from a stainless steel surface showed no statistically significant differences in performance between the ANSR method and the U.S. Food and Drug Administration Bacteriological Analytical Manual or U.S. Department of Agriculture-Food Safety and Inspection Services Microbiology Laboratory Guidebook reference culture procedures. Results of inclusivity and exclusivity testing were unchanged from those of the original validation study; exclusivity was 100% and inclusivity was 99.1% with only a single strain of Salmonella Weslaco testing negative. Robustness testing was also conducted, with variations to lysis buffer volume, lysis time, and sample volume having no demonstrable effect on assay results.

Validation of the NeoFilm for Yeast and Mold Method for Enumeration of Yeasts and Molds in Select Foods.

NeoFilm Yeast and Mold (Y&M), also known as Sanita-kun Yeasts and Molds, is a simple, effective device used for the enumeration of yeasts and molds. It consists of a nonwoven fabric on which a layer of microbial nutrients is deposited in a film. A 1 mL sample homogenate is applied to the membrane and this, in turn, is incubated for 48-72 h at 25°C. Sample homogenates were prepared using two different diluents for customer convenience: phosphate buffered saline (PBS) and 0.1% peptone water. In comparative testing of breaded chicken nuggets, dry pet food, orange juice concentrate, yogurt, and cake mix, there were statistically significant differences in the counts obtained by the NeoFilm Y&M and U.S. Food and Drug Administration Bacteriological Analytical Manual reference culture methods only in the following instances: medium level for orange juice with PBS as diluent and low level for pet food with 0.1% peptone water as diluent, where reference method counts were higher than those of NeoFilm; medium level for cake mix with PBS, and low and medium levels for cake mix with 0.1% peptone water, where NeoFilm produced higher counts than the reference method. In addition to the method comparison study with five matrixes, robustness and stability/lot-to-lot testing were also performed. Results of robustness testing showed no significant effect on results even with perturbation to three assay parameters simultaneously. Results of testing of three lots of devices ranging in age from 2 to 26 months post-manufacture showed no significant differences in performance.

Validation of the ANSR® Listeria Method for Detection of Listeria spp. in Selected Foods.

ANSR® Listeria was previously certified as Performance Tested Method(SM) 101202 for detection of Listeria spp. on selected environmental surfaces. This study proposes a matrix extension to the method for detection of Listeria spp. in selected food matrixes. The method is an isothermal nucleic acid amplification assay based on the nicking enzyme amplification reaction technology. Following single-step sample enrichment for 16-24 h, the assay is completed in less than 50 min, requiring only simple instrumentation. Inclusivity testing was performed using a panel of 51 strains of Listeria spp., representing the species L. grayi, L. innocua, L. ivanovii, L. monocytogenes, L. seeligeri, and L. welshimeri. All strains tested were detected by the ANSR assay. Exclusivity testing of 30 strains representing non-Listeria Gram-positive bacteria yielded no evidence of cross-reactivity. Performance of the ANSR method for detection of Listeria spp. was compared to that of reference culture procedures for pasteurized liquid egg, pasteurized 2% milk, Mexican-style cheese, ice cream, smoked salmon, lettuce, cantaloupe, and guacamole. Data obtained in these unpaired studies and analyzed using a probability of detection model demonstrated that there were no statistically significant differences in results between the ANSR and reference culture methods, except for milk at 16 h and cantaloupe. In milk and smoked salmon, ANSR sensitivity was low at 16 h and therefore the recommended incubation time is 24 h. In cantaloupe, ANSR was found to be more sensitive than the reference culture method at both 16 and 24 h in independent laboratory testing. The ANSR Listeria method can be used as an accurate, rapid, and simple alternative to standard culture methods for detection of Listeria spp. in selected food types.

Validation of the ANSR Salmonella method for detection of Salmonella spp. in a variety of foods. Performance Tested Method 061203.

This study represents a proposal to extend the matrix claims for the ANSR Salmonella test, Performance Tested Method 061203. The test is based on the nicking enzyme amplification reaction (NEAR) isothermal nucleic acid amplification technology. The assay platform features simple instrumentation, minimal labor, and following a single-step 16-24 h enrichment (depending on sample type), an extremely short assay time of 30 min including sample preparation. Detection is real-time using fluorescent molecular beacon probes. ANSR Salmonella was originally validated for detection of Salmonella spp. in chicken carcass rinse, raw ground turkey, raw ground beef, hot dogs, and oat cereal, and on stainless steel, plastic, sealed concrete, ceramic tile, and rubber surfaces. The matrixes tested in this study include pet food, ice cream, soy flour, raw almonds, peanut butter, spinach, black pepper, raw frozen shrimp, cocoa powder, and pasteurized dried egg. In unpaired comparative testing there were no statistically significant differences in the number of positive results obtained with the ANSR and the reference culture methods. Enrichment for 16 h was effective for all commodities tested except ice cream, black pepper, dried pasteurized egg, and 375 g samples of dry pet food, for which enrichment for 24 h is indicated.

Validation of the Soleris direct yeast and mold method for semiquantitative determination of yeast and mold in a variety of foods.

A study was carried out to determine the efficacy of the Soleris Direct Yeast and Mold (DYM) automated growth-based method for semiquantitative detection of yeast and mold in a variety of food products. A probability of detection (POD) statistical model was used to compare Soleris results at multiple test thresholds (dilutions) with plate counts determined using the U.S. Food and Drug Administration Bacteriological Analytical Manual, Chapter 18, dilution plating procedure. Fourteen naturally contaminated food products were tested, with Soleris testing performed at three or more threshold levels for each food. Using the POD model, the majority of Soleris test results were in statistical agreement with the reference plating procedures. The exceptions included a single threshold level in yogurt, black pepper, dried fruit, and dry pet food, and two levels in nonfat dry milk and saw palmetto powder. In all but one of these instances, the exception being pet food, the statistical disagreement was due to Soleris estimating a higher level of contamination than the reference method. Results of ruggedness testing showed that the Soleris method produced accurate results even when significant variances in a critical operating parameter, incubation temperature, were introduced. Results of the internal and independent laboratory validation studies showed that the Soleris DYM method can be used as an accurate alternative to conventional dilution plating procedures for evaluation of yeast and mold counts at threshold levels, while saving as much as 72 h in analysis time.

Evaluation of the ANSR for Salmonella assay for identification of Salmonella spp. from colony picks from selective/differential agar media: first action 2013.14.

A collaborative study was conducted to evaluate performance of the ANSR for Salmonella assay for identification of Salmonella spp. from colony picks taken from selective/differential agar media. The ANSR Salmonella assay is an isothermal nucleic acid amplification test based on the nicking enzyme amplification reaction chemistry. The test can be completed in less than 40 min including sample preparation. A total of 18 laboratories representing industry, government, academic, and commercial testing laboratories participated in the study. Each collaborator tested up to 84 samples, comprised of colony picks of six Salmonella spp. and six non-salmonellae taken from six selective/differential agar media as well as tryptic soy agar. A total of 1441 analyses were performed, 1416 of which gave the correct identification, for overall accuracy of 98.3%. For identification of Salmonella spp., 755 of 756 tests (99.9%) produced the correct result. For identification of non-salmonellae as such, 661 of 685 assays (96.5%) produced the correct result. Of the 18 laboratories, 15 produced data sets with 99-100% accuracy. The majority of false-positive results were clustered in three laboratories; analysis of raw data suggests procedural difficulties in at least two cases, which may explain the atypical data from these collaborators. The ANSR Salmonella assay can be used as a rapid, accurate adjunct or alternative to biochemical testing for identification of presumptive Salmonella spp. isolates.

Validation of the ANSR Salmonella method for detection of Salmonella spp. in selected foods and environmental samples.

ANSR Salmonella is a new molecular diagnostic assay for detection of Salmonella spp. in foods and environmental samples. The test is based on the nicking enzyme amplification reaction (NEAR) isothermal nucleic acid amplification technology. The assay platform features simple instrumentation, minimal labor, and, following a single-step 10-24 h enrichment (depending on sample type), an extremely short assay time of 30 min, including sample preparation. Detection is real-time using fluorescent molecular beacon probes. Inclusivity testing was performed using a panel of 113 strains of S. enterica and S. bongori, representing 109 serovars and all genetic subgroups. With the single exception of the rare serovar S. Weslaco, all serovars and genetic subgroups were detected. Exclusivity testing of 38 non-salmonellae, mostly Enterobacteriaceae, yielded no evidence of cross-reactivity. In comparative testing of chicken carcass rinse, raw ground turkey, raw ground beef, hot dogs, and oat cereal, there were no statistically significant differences in the number of positive results obtained with the ANSR and the U.S. Department of Agriculture-Food Safety and Inspection Service or U.S. Food and Drug Administration/Bacteriological Analytical Manual reference culture methods. In testing of swab or sponge samples from five different environmental surfaces, four trials showed no statistically significant differences in the number of positive results by the ANSR and the U.S. Food and Drug Administration/ Bacteriological Analytical Manual reference methods; in the trial with stainless steel surface, there were significantly more positive results by the ANSR method. Ruggedness experiments showed a high degree of assay robustness when deviations in reagent volumes and incubation times were introduced.

Economic Decisions, Attractiveness, and Intrasexual Competition during Menstrual Cycle in the Ultimatum Game.

Introduction: it seems that, in the phase of greatest fertility, women's intrasexual competition (toward attractive women who live nearby) increases due to access to resources, status, and biologically desirable partners. Objective: to compare the economic decisions (ED) during the ovulatory (OP) and luteal (LP) phases of the menstrual cycle (MC) with exposure to two stimuli: a photograph of a more attractive woman and a photograph of a less attractive woman, through the ultimatum game (UG). Methodology: the research followed a cross-sectional design between subjects to see group differences by contrasting hypotheses. The sampling was probabilistic, with a sample of 100 heterosexual women, students at a public university with an age range of 18 to 24 years, with regular MC, who did not use hormonal contraceptive methods and did not have any endocrine condition. The inverse counting method with confirmation was applied to identify CM phases; and the UG to evaluate the DE. Results: the phases of the MC had no effect on the ED; the women behaved similarly in their decisions, regardless of the phase of the cycle they were in or the type of stimulus to which they were exposed. Conclusion: OP and LP do not affect the ED of women when they are exposed to an attractive stimulus. The discussion is made considering the evolutionary theory of the ovulatory shift hypothesis.

Introducción: parece ser que, en su fase de mayor fertilidad, la competencia intrasexual de la mujer (con mujeres atractivas y que viven cerca) aumenta por el acceso a recursos, estatus y parejas biológicamente deseables. Objetivo: comparar las decisiones económicas (DE) en las fases ovulatoria (FO) y lútea (FL) del ciclo menstrual (CM) con exposición a dos estímulos: fotografía de una mujer de mayor atractivo y fotografía de una mujer de menor atractivo, a través del juego del ultimátum (UG). Metodología: la investigación tuvo un diseño cross-sectional entre sujetos para ver diferencia de grupos mediante contraste de hipótesis. El muestreo fue probabilístico, con una muestra de 100 mujeres heterosexuales, estudiantes de una universidad pública con un rango de edad de 18 a 24 años, con CM regulares, que no usaran métodos anticonceptivos hormonales y no tuvieran ninguna afección endocrina. Resultados: las fases del CM no tuvieron efectos sobre las DE; las mujeres se comportaron de forma similar en sus decisiones, sin importar la fase del ciclo en la que se encontraban o el tipo de estímulo al que fueron expuestas. Conclusión: las FO y FL no afectan las DE de las mujeres cuando son expuestas a un estímulo atractivo. La discusión se hace a la luz de la teoría evolutiva de la hipótesis del cambio ovulatorio.

Fundamental social motives measured across forty-two cultures in two waves.

How does psychology vary across human societies? The fundamental social motives framework adopts an evolutionary approach to capture the broad range of human social goals within a taxonomy of ancestrally recurring threats and opportunities. These motives-self-protection, disease avoidance, affiliation, status, mate acquisition, mate retention, and kin care-are high in fitness relevance and everyday salience, yet understudied cross-culturally. Here, we gathered data on these motives in 42 countries (N = 15,915) in two cross-sectional waves, including 19 countries (N = 10,907) for which data were gathered in both waves. Wave 1 was collected from mid-2016 through late 2019 (32 countries, N = 8,998; 3,302 male, 5,585 female; Mage = 24.43, SD = 7.91). Wave 2 was collected from April through November 2020, during the COVID-19 pandemic (29 countries, N = 6,917; 2,249 male, 4,218 female; Mage = 28.59, SD = 11.31). These data can be used to assess differences and similarities in people's fundamental social motives both across and within cultures, at different time points, and in relation to other commonly studied cultural indicators and outcomes.

Platelet-rich fibrin constructs elute higher concentrations of transforming growth factor-ß1 and increase tendon cell proliferation over time when compared to blood clots: a comparative in vitro analysis.

OBJECTIVE: To compare the concentration of a representative growth factor (transforming growth factor-beta [TGF-ß]1) eluted from a platelet-rich fibrin matrix (PRFMatrix), a platelet-rich fibrin membrane (PRFMembrane), and a whole blood clot (BC) over time, and to compare the mitogenic effect of the eluents from each construct. STUDY DESIGN: In vitro study. SAMPLE POPULATION: PRFMatrix, PRFMembrane, and BC (n=4/construct/time point). METHODS: Each construct was placed in tissue culture wells containing media for 7 days. The media was collected and replenished on days 1, 3, 5, and 7 and the concentration of eluted TGF-ß1 was measured by enzyme-linked immunosorbent assay. Canine tendon cells were subjected to additional aliquots of the conditioned media and the amount of cell proliferation compared. RESULTS: The media from both PRFM (PRFMatrix and PRFMembrane) constructs contained significantly more (P≤.026) TGF-ß1 at days 1 and 3 and produced a significant increase (P≤.044) in cell proliferation at all time points compared with the BC. The PRFMembrane media contained significantly more (P≤.05) TGF-ß1 at days 1 and 3 and produced a significant increase (P≤.002) in cell proliferation at all time points compared with the PRFMatrix. CONCLUSIONS: Both PRFM constructs are comprised of a dense fibrin scaffold that contains increased concentrations of TGF-ß1 and are capable of increasing tendon cell proliferation over time when compared with a BC. CLINICAL RELEVANCE: The sustained increase in growth factor availability in PRFM constructs may be beneficial in the healing of biologically compromised tissues.

Loss of homeostatic tension induces apoptosis in tendon cells: an in vitro study.

Apoptosis (programmed cell death) has been identified as a histopathologic feature of tendinopathy. While the precise mechanism(s) that triggers the apoptotic cascade in tendon cells has not been identified, it has been theorized that loss of cellular homeostatic tension following microscopic damage to individual tendon fibrils could be the stimulus for initiating the pathologic events associated with tendinopathy. To determine if loss of homeostatic tension following stress deprivation could induce apoptosis in tendon cells, rat tail tendons were stress-deprived or cyclically loaded (3% strain at 0.17 Hz) for 24 hours under tissue culture conditions. Caspase-3 (an upstream mediator of apoptosis) mRNA expression was evaluated using quantitative polymerase chain reaction and caspase-3 protein synthesis was identified using immunohistochemistry. Apoptotic cells were identified histologically using an antibody for single-stranded DNA. Stress deprivation for 24 hours resulted in an increase in caspase-3 mRNA expression when compared to fresh controls or cyclically loaded tendons. Stress deprivation also increased the percentage of apoptotic cells (10.59% +/- 2.80) compared to controls (1.87% +/- 1.07) or cyclically loaded tendons (3.73% +/- 0.87). These data suggest loss of homeostatic tension following stress deprivation induces apoptosis in rat tail tendon cells.

Loss of homeostatic strain alters mechanostat "set point" of tendon cells in vitro.

Tendon cells respond to mechanical loads. The character (anabolic or catabolic) and sensitivity of this response is determined by the mechanostat set point of the cell, which is governed by the cytoskeleton and its interaction with the extracellular matrix. To determine if loss of cytoskeletal tension following stress deprivation decreases the mechanoresponsiveness of tendon cells, we cultured rat tail tendons under stress-deprived conditions for 48 hours and then cyclically loaded them for 24 hours at 1%, 3%, or 6% strain at 0.17 Hz. Stress deprivation upregulated MMP-13 mRNA expression and caused progressive loss of cell-matrix contact compared to fresh controls. The application of 1% strain to fresh tendons for 24 hours inhibited MMP-13 mRNA expression compared to stress-deprived tendons over the same period. However, when tendons were stress-deprived for 48 hours and then subjected to the same loading regime, the inhibition of MMP-13 mRNA expression was decreased. In stress-deprived tendons, it was necessary to increase the strain magnitude to 3% to achieve the same level of MMP-13 mRNA inhibition seen in fresh tendons exercised at 1% strain. The data suggest loss of cytoskeletal tension alters the mechanostat set point and decreases the mechanoresponsiveness of tendon cells.

The effect of stress-deprivation and cyclic loading on the TIMP/MMP ratio in tendon cells: an in vitro experimental study.

PURPOSE: To determine the effect of stress deprivation and cyclic loading on TIMP-1/MMP-13 mRNA expression ratio in rat tail tendon (RTT) cells. METHOD: Adult RTTs were stress-deprived for 0, 24, 48, or 72 hours in the presence or absence of a MMP inhibitor (ilomastat), or subjected to 1%, 3%, or 6% strain for 24 h under tissue culture conditions. TIMP-1 and MMP-13 (rat interstitial collagenase) mRNA expression were measured using quantitative PCR and TIMP/MMP ratios were calculated for each group. RESULTS: The ratio of TIMP-1 to MMP-13 in control RTTs was 3.73:1 +/- 0.73. Stress deprivation for 24 h significantly decreased the TIMP-1/MMP-13 ratio (0.25:1 +/- 0.04) and MMP-13 expression continued to increase significantly with time of stress deprivation. Inhibition of MMP-13 mRNA expression with ilomastat in stress-deprived samples did not alter TIMP-1 expression when compared to normal controls. Cyclic loading significantly increased TIMP-1/MMP-13 expression at all strain levels examined. CONCLUSIONS: RTTs normally have a positive TIMP-1/MMP-13 expression ratio. While cyclic loading increased the TIMP-1/MMP-13 ratio, loss of cellular homeostatic tension inversed this ratio through a significant increase in MMP-13 mRNA expression rather than a decrease in TIMP expression. A negative TIMP/MMP ratio has been implicated in the pathogenesis of tendinopathy. Increasing the TIMP/MMP ratios in these patients through exercise may be beneficial in the management of tendinopathy.

The location in cartilage of infectious retrovirus in cats infected with feline leukemia virus.

BACKGROUND: Previous studies have suggested that articular cartilage allografts were not likely to transmit infectious retrovirus since viral DNA could not be isolated from chondrocytes of infected individuals. However, the ability of the extracellular matrix of articular cartilage to harbor and transmit a retrovirus has not been examined. We hypothesized that articular cartilage fragments, but not isolated chondrocytes, from cats systemically infected with feline leukemia virus (FeLV) are capable of transmitting infectious retrovirus. METHODS: Fresh cartilage segments and chondrocytes isolated from cats systemically infected with feline leukemia virus were used in this study. Feline embryonic fibroblast cells were cocultured with segments of cartilage, isolated chondrocytes, or fragments of cortical bone from each infected cat. The FeLV p27 antigen was measured in the coculture media by enzyme-linked immunosorbent assay. In addition, FeLV proviral nucleic acids were quantified by real-time quantitative polymerase chain reaction with use of DNA extracted from feline embryonic fibroblast cell cocultures as well as isolated chondrocytes. Immunohistochemistry was used to assess for FeLV p27 antigen in both intact cartilage fragments and isolated chondrocytes. RESULTS: Feline embryonic fibroblast cells cocultured with cartilage fragments from each of the five FeLV-infected cats all demonstrated high levels of proviral DNA, indicating transmission of infective virus. In addition, media from all cocultures of feline embryonic fibroblast cells and chondral fragments became positive for p27 antigen, indicating active viral replication. In contrast, cocultures of feline embryonic fibroblast cells and isolated chondrocytes from all FeLV-infected cats were negative for proviral DNA and p27 antigen. Likewise, no proviral nucleic acids could be detected in isolated chondrocytes from any infected cats. Cocultures of feline embryonic fibroblast cells with cortical bone fragments were positive for proviral DNA and p27 antigen. Immunohistochemical staining of cartilage fragments from FeLV-infected cats demonstrated the presence of p27 antigen throughout the extracellular matrix, but the p27 antigen was not detected in isolated chondrocytes. CONCLUSIONS: Articular cartilage fragments can readily transmit infectious retrovirus, but isolated chondrocytes were likely not the source of the infectious virus because they did not harbor proviral DNA or p27 antigen.

Matrix metalloproteinase inhibitors prevent a decrease in the mechanical properties of stress-deprived tendons: an in vitro experimental study.

BACKGROUND: An increase in matrix metalloproteinases (MMPs) and the resulting degradation of the extracellular matrix have been implicated in the pathogenesis of tendinopathy. Studies have documented the beneficial effects of MMP inhibitors used to treat pathologic conditions in which MMP activity has had a negative effect on connective tissues. HYPOTHESIS: Matrix metalloproteinase inhibitors will prevent the decrease in material properties associated with tendon stress deprivation by inhibiting MMP activity. STUDY DESIGN: Controlled laboratory study. METHODS: Rat tail tendons were subjected to 7 days of in vitro stress deprivation with and without the addition of 1 of 2 broad-spectrum MMP inhibitors (doxycycline and ilomastat). The material properties (ultimate tensile stress, strain, and tensile modulus) of the tendons were compared with each other and with fresh control tendons. In addition, tendons from each group were evaluated for MMP-13 messenger RNA expression, MMP-13 protein synthesis, MMP-13 activity, and pericellular matrix morphology. RESULTS: Both MMP inhibitors resulted in a statistically significant reduction in MMP activity in 7 day stress-deprived tendons when compared with nontreated, stress-deprived tendons. Similarly, tendons treated with either ilomastat or doxycycline had significantly improved material properties. MMP-13 messenger RNA expression and protein synthesis were not significantly affected by either MMP inhibitor. Both MMP inhibitors were able to maintain the integrity of the pericellular matrix when compared with nontreated, stress-deprived tendons. CONCLUSION: Matrix metalloproteinase inhibitors prevented the activation of MMP-13 and significantly inhibited pericellular matrix degeneration and the loss of material properties associated with stress deprivation. CLINICAL RELEVANCE: Matrix metalloproteinase inhibitors may play a supportive role in the treatment of tendinopathy by limiting the MMP-mediated degradation of the extracellular matrix.