Effect of photobiomodulation on the behaviour of mesenchymal stem cells in three-dimensional cultures

Photobiomodulation (PBM) has been proposed as a strategy to improve the regenerative capacity of human adipose-derived stem cells (hASCs). Yet, this effect has been proved in 2D culture conditions. To analyze the effect of different doses of laser irradiation (660 nm) with different levels of energy (1 J, 2 J and 6 J) on hASCs cultured at 2D and 3D conditions. We used gellan gum spongy-like hydrogels as a biomaterial to 3D culture hASCs. Different doses (1-7 daily irradiations) and energy levels (1-6 J) of PBM were applied, and the metabolic activity, viability, proliferation, and release of ROS and IL-8 was evaluated up to 7 days. In 3D, cell proliferation increased at high energy (6 J) and after a single dose of irradiation, while in 2D, metabolic activity and proliferation was enhanced only after 3 doses and independently of the energy. More than 1 dose was needed to promote ROS secretion both in 2D and 3D culture conditions. Interestingly, a decrease of IL-8 secretion was detected only in 3D after 3-7 daily irradiations. Overall, hASCs response to PBM was not only dependent on the energy level and the number of applied stimuli, but also on the in vitro culture conditions.

Extracellular matrix in skin diseases: The road to new therapies

BACKGROUND

The extracellular matrix (ECM) is a vital structure with a dynamic and complex organization that plays an essential role in tissue homeostasis. In the skin, the ECM is arranged into two types of compartments: interstitial dermal matrix and basement membrane (BM). All evidence in the literature supports the notion that direct dysregulation of the composition, abundance or structure of one of these types of ECM, or indirect modifications in proteins that interact with them is linked to a wide range of human skin pathologies, including hereditary, autoimmune, and neoplastic diseases. Even though the ECM's key role in these pathologies has been widely documented, its potential as a therapeutic target has been overlooked.

AIM OF REVIEW

This review discusses the molecular mechanisms involved in three groups of skin ECM-related diseases - genetic, autoimmune, and neoplastic - and the recent therapeutic progress and opportunities targeting ECM.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This article describes the implications of alterations in ECM components and in BM-associated molecules that are determinant for guaranteeing its function in different skin disorders. Also, ongoing clinical trials on ECM-targeted therapies are discussed together with future opportunities that may open new avenues for treating ECM-associated skin diseases.

Gellan gum spongy-like hydrogel-based dual antibiotic therapy for infected diabetic wounds

Diabetic foot infection (DFI) is an important cause of morbidity and mortality. Antibiotics are fundamental for treating DFI, although bacterial biofilm formation and associated pathophysiology can reduce their effectiveness. Additionally, antibiotics are often associated with adverse reactions. Hence, improved antibiotic therapies are required for safer and effective DFI management. On this regard, drug delivery systems (DDSs) constitute a promising strategy. We propose a gellan gum (GG)-based spongy-like hydrogel as a topical and controlled DDS of vancomycin and clindamycin, for an improved dual antibiotic therapy against methicillin-resistant Staphylococcus aureus (MRSA) in DFI. The developed DDS presents suitable features for topical application, while promoting the controlled release of both antibiotics, resulting in a significant reduction of in vitro antibiotic-associated cytotoxicity without compromising antibacterial activity. The therapeutic potential of this DDS was further corroborated in vivo, in a diabetic mouse model of MRSA-infected wounds. A single DDS administration allowed a significant bacterial burden reduction in a short period of time, without exacerbating host inflammatory response. Taken together, these results suggest that the proposed DDS represents a promising strategy for the topical treatment of DFI, potentially overcoming limitations associated with systemic antibiotic administration and minimizing the frequency of administration.

An optimized mouse model of Staphylococcus aureus infected diabetic ulcers

OBJECTIVE

Diabetic foot infection (DFI) represents a major healthcare burden, for which treatment is challenging owing to the pathophysiological alterations intrinsic to diabetes and the alarming increase of antimicrobial resistance. Novel therapies targeting DFI are therefore a pressing research need for which proper models of disease are required.

RESULTS

Here, we present an optimized diabetic mouse model of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds, that resemble key features of DFI, such as pathogen invasion through wound bed and surrounding tissue, necrosis, persistent inflammation and impaired wound healing. Thus, in a time-efficient manner and using simple techniques, this model represents a suitable approach for studying emerging therapies targeting DFI caused by MRSA.

Inactivation of Aspergillus species in real water matrices using medium pressure mercury lamps

The aim of this work is to understand the inactivation efficiency of medium pressure mercury lamps, measured in terms of growth inhibition as well as cell death, damage and response, using three strains from three different Aspergillus species (A. fumigatus, A. niger and, A. terreus) spiked in filtered surface water. A complete characterization of the effect of the treatment on each strain of the fungal species was assessed considering spores' morphology, cell wall integrity and enzymatic activity, the formation of pyrimidine dimers in the DNA and proteome analysis. Results showed that, when subjected to medium pressure mercury lamps, A. niger is the most resistant to inactivation, that both A. fumigatus and A. niger suffer more morphological changes and present a higher number of damaged spores and A. terreus presented more dead spores. DNA damages detected in A. niger were able to be repaired to some extent, under both light and dark conditions. Finally, proteome analysis showed that the UV radiation treatment triggered different types of stress response, including cell wall reorganization and DNA repair in A. fumigatus and A. terreus, and oxidative stress responses like the increase in production of citric acid and itaconic acid in A. niger and A. terreus, respectively.

The 15-years trajectory of the Health, Well-being and Aging (SABE) study in São Paulo State, Brazil

The Health, Well-being and Aging (SABE - Saúde, Bem-estar e Envelhecimento) study was developed by the Pan American Health Organization (OPAS/OMS) to provide information on the living conditions of the elderly. The multi-center survey on health and well-being of the elderly was carried out in seven urban areas in Latin America and the Caribbean. The study took place between October 1999 and December 2000 in Argentina, Barbados, Brazil, Chile, Cuba, Mexico, and Uruguay. In 2006, only in Brazil, the SABE Study became a longitudinal and multiple cohort study with the aid of the São Paulo Research Foundation (FAPESP) and the Ministry of Health. In each cohort (2006, 2010 and 2015), data was collected among the elderly who were participants in 2000, and new 60 to 64-year-old subjects were inserted. The probabilistic sample of the participating individuals was obtained through the method of multi-stage conglomerates sampling by stratifying the primary units. We also considered the socioeconomic strata of the municipality urban area. The baseline for carrying out the sample calculation was the population count of the Brazilian Institute of Geography and Statistics (IBGE). Data was collected by trained interviewers. They used a standardized questionnaire to retrieve information regarding, for example, cognitive assessment, health status, and use and access to services. At the moment, the SABE Study follows 1,224 elderly individuals. The information collected from the SABE Study is available through the electronic address <http://hygeia3.fsp.usp.br/sabe/>. The aging process occurs differently when factors such as sex and socioeconomic aspects are considered. Thus, accompanying the elderly over time and knowing their living conditions are essential for proposing public policies according to reality.

Key messages

The Health, Well-being and Aging (SABE) study has been monitoring elderly people since 2000 in the city of São Paulo and provides information on their living conditions. The monitoring of the elderly enables the development of public policies that are more focused on the needs presented.

Mitochondria, endoplasmic reticulum and innate immune dysfunction in mood disorders: Do Mitochondria-Associated Membranes (MAMs) play a role?

Mood disorders like major depression and bipolar disorder (BD) are among the most prevalent forms of mental illness. Current knowledge of the neurobiology and pathophysiology of these disorders is still modest and clear biological markers are still missing. Thus, a better understanding of the underlying pathophysiological mechanisms to identify potential therapeutic targets is a prerequisite for the design of new drugs as well as to develop biomarkers that help in a more accurate and earlier diagnosis. Multiple pieces of evidence including genetic and neuro-imaging studies suggest that mood disorders are associated with abnormalities in endoplasmic-reticulum (ER)-related stress responses, mitochondrial function and calcium signalling. Furthermore, deregulation of the innate immune response has been described in patients diagnosed with mood disorders, including depression and BD. These disease-related events are associated with functions localized to a subdomain of the ER, known as Mitochondria-Associated Membranes (MAMs), which are lipid rafts-like domains that connect mitochondria and ER, both physically and biochemically. This review will outline the current understanding of the role of mitochondria and ER dysfunction under pathological brain conditions, particularly in major depressive disorder (MDD) and BD, that support the hypothesis that MAMs can act in these mood disorders as the link connecting ER-related stress response and mitochondrial impairment, as well as a mechanisms behind sterile inflammation arising from deregulation of innate immune responses. The role of MAMs in the pathophysiology of these pathologies and its potential relevance as a potential therapeutic target will be discussed.

Local Tuberculosis Georeference: a tool to define BCG vaccination in high-incidence area in Portugal

Issue

Tuberculosis (TB) incidence in Portugal is < 20/100000 people, with high-incidence municipalities in urban areas such as Amadora. In 2016, the national vaccination programme moved the BCG vaccine from universal to restricted risk groups. Amadora, due to the higher-incidence area, maintained a universal vaccination policy. Recently, it was hypothesized that vaccination could be applied to specific parishes even in high incidence counties.

Description

We aimed to identify specific geographic areas with higher risk of TB to help redefine the local BCG vaccination policy. We proposed to georeference active TB cases between 2015 and 2017, in Amadora, to then assess the incidence per parish and statistical section. We also aimed at identifying geo-clusters and density of cases.

Methods

(1) notified TB cases from 1 January of 2015 to 31 December 2017 were extracted from TB surveillance system; (2) cases of latent TB infection (LTBI), cases out of Amadora’s bounds and without national ID were excluded; (3) ArcGis®Online and associated maps were used to provide populational estimates; (4) cumulative incidence was calculated per year and averaged for the 3-year period; (5) Clusters were determined using distance and simple density of cases was calculated using Kernel algorithm.

Results

Considering the 6 parishes of Amadora, the 3-year cumulative incidence varied from 19.58 to 38.3 per 100000 hab. The highest incidence was found on the parish with the best socio-economic profile. 14 geo-clusters were mapped; 3 matched known deprived neighborhoods. Overall density was higher in these neighborhoods.

Lessons

With this approach we found that deprived neighborhoods had higher levels of case density, but 3-year cumulative incidence was higher on the parish considered to have low occurrence of TB. As such, and due to the intense population flows in Amadora, the local public health unit recommended the persistence of BCG vaccination to all residents of the municipality.

Key messages

Georeferecing supported our recommendation to mantain a universal BCG vaccination policy. Georeferencing associated to surveillance systems is highly useful to ensure evidence based public health practices, even at the local level.

Strategies for the hypothermic preservation of cell sheets of human adipose stem cells

Cell Sheet (CS) Engineering is a regenerative medicine strategy proposed for the treatment of injured or diseased organs and tissues. In fact, several clinical trials are underway using CS-based methodologies. However, the clinical application of such cell-based methodologies poses several challenges related with the preservation of CS structure and function from the fabrication site to the bedside. Pausing cells at hypothermic temperatures has been suggested as a valuable method for short-term cell preservation. In this study, we tested the efficiency of two preservation strategies, one using culture medium supplementation with Rokepie and the other using the preservation solution Hypothermosol, in preserving human adipose stromal/stem cells (hASC) CS-like confluent cultures at 4°C, during 3 and 7 days. Both preservation strategies demonstrated excellent ability to preserve cell function during the first 3 days in hypothermia, as demonstrated by metabolic activity results and assessment of extracellular matrix integrity and differentiation potential. At the end of the 7^th day of hypothermic incubation, the decrease in cell metabolic activity was more evident for all conditions. Nonetheless, hASC incubated with Rokepie and Hypothermosol retained a higher metabolic activity and extracellular matrix integrity in comparison with unsupplemented cells. Differentiation results for the later time point showed that supplementation with both Rokepie and Hypothermosol rescued adipogenic differentiation potential but only Rokepie was able to preserve hASC osteogenic potential.

Pain and quality of life in knee osteoarthritis, chronic low back pain and fibromyalgia: a comparative cross-sectional study

The objective of our study was to compare pain and health-related quality of life among patients with knee osteoarthritis (OA), chronic nonspecific low back pain (CNLBP) and fibromyalgia (FM). This cross-sectional study included 87 subjects, who were divided into three groups according to their diagnosis: knee OA (n=29), CNLBP (n=29) and FM (n=29), between March 2013 and March 2014. Pain intensity was measured using the Numeric Pain Rating Scale (NPRS), quality of pain using the McGill Pain Questionnaire (MPQ) and health-related quality of life using the 36-item Short-Form Health Survey (SF-36). Painful body areas were marked on a pain map. No statistically significant differences between groups were found for NPRS. Regarding MPQ, the knee OA group presented a lower pain-rating index in contrast to the CNLBP and FM groups, and no significant differences were found between the CNLBP and FM groups. A greater number of characteristic pain descriptors and painful locations were found in the FM group than in the CNLBP or knee OA groups. Regarding SF-36, the FM group presented statistically significant lower values for bodily pain in contrast to the knee OA group. Even though the global pain intensity was similar between groups, the findings suggest that the FM group presented the worst pain experience and a lower health-related quality of life than the knee OA group in terms of bodily pain. They also suggest that the pain experience was worse for the CNLBP group than for the knee OA group but health-related quality of life was similar.

Stem Cell-Containing Hyaluronic Acid-Based Spongy Hydrogels for Integrated Diabetic Wound Healing

The detailed pathophysiology of diabetic foot ulcers is yet to be established and improved treatments are still required. We propose a strategy that directs inflammation, neovascularization, and neoinnervation of diabetic wounds. Aiming to potentiate a relevant secretome for nerve regeneration, stem cells were precultured in hyaluronic acid-based spongy hydrogels under neurogenic/standard media before transplantation into diabetic mice full-thickness wounds. Acellular spongy hydrogels and empty wounds were used as controls. Re-epithelialization was attained 4 weeks after transplantation independently of the test groups, whereas a thicker and more differentiated epidermis was observed for the cellular spongy hydrogels. A switch from the inflammatory to the proliferative phase of wound healing was revealed for all the experimental groups 2 weeks after injury, but a significantly higher M2(CD163⁺)/M1(CD86⁺) subtype ratio was observed in the neurogenic preconditioned group that also failed to promote neoinnervation. A higher number of intraepidermal nerve fibers were observed for the unconditioned group probably due to a more controlled transition from the inflammatory to the proliferative phase. Overall, stem cell-containing spongy hydrogels represent a promising approach to enhance diabetic wound healing by positively impacting re-epithelialization and by modulating the inflammatory response to promote a successful neoinnervation.

Stem Cells in Skin Wound Healing: Are We There Yet?

Significance: Cutaneous wound healing is a serious problem worldwide that affects patients with various wound types, resulting from burns, traumatic injuries, and diabetes. Despite the wide range of clinically available skin substitutes and the different therapeutic alternatives, delayed healing and scarring are often observed. Recent Advances: Stem cells have arisen as powerful tools to improve skin wound healing, due to features such as effective secretome, self-renewal, low immunogenicity, and differentiation capacity. They represent potentially readily available biological material that can particularly target distinct wound-healing phases. In this context, mesenchymal stem cells have been shown to promote cell migration, angiogenesis, and a possible regenerative rather than fibrotic microenvironment at the wound site, mainly through paracrine signaling with the surrounding cells/tissues. Critical Issues: Despite the current insights, there are still major hurdles to be overcome to achieve effective therapeutic effects. Limited engraftment and survival at the wound site are still major concerns, and alternative approaches to maximize stem cell potential are a major demand. Future Directions: This review emphasizes two main strategies that have been explored in this context. These comprise the exploration of hypoxic conditions to modulate stem cell secretome, and the use of adipose tissue stromal vascular fraction as a source of multiple cells, including stem cells and factors requiring minimal manipulation. Nonetheless, the attainment of these approaches to target successfully skin regeneration will be only evident after a significant number of in vivo works in relevant pre-clinical models.

Postural control and balance self-efficacy in women with fibromyalgia: are there differences?

BACKGROUND

Fibromyalgia (FM) is a rheumatic disease characterized by chronic widespread pain and symptoms such as fatigue, sleep disturbances, cognitive difficulties, and depression. Postural instability is a debilitating disorder increasingly recognized as part of FM.

OBJECTIVE

To assess and compare postural control and balance self-efficacy in women with and without FM and verify the association of these variables with pain, symptom severity, and strength.

DESIGN

Case-control study

SETTING

Physiotherapeutic Clinical Research and Electromyography Laboratory Department of Physical Therapy, Speech Therapy, and Occupational Therapy, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil.

POPULATION

Case-control study of 117 women ranging from age 35 to 60 years. Of these, 67 had FM.

METHODS

Posture control was assessed with the modified clinical test of sensory interaction on balance with patients in forceplates, balance self-efficacy with the Activities-specific Balance Confidence Scale, pain severity with the Visual Analog Scale, tender point pain threshold with digital algometry, symptom severity with the fibromyalgia impact questionnaire, and lower limb strength with a dynamometer.

RESULTS

Individuals with FM had impaired postural control showing increased speed of oscillation of the center of gravity (P=0.004) and decreased balance self-efficacy (P<0.001). They had moderate to excellent correlations of balance self-efficacy with pain (r=0.7, P<0.01), muscle strength (r=0.52, P<0.01), and symptom severity (r=0.78, P<0.10) compared with the control group. Correlation of postural control with the same variables was weak.

CONCLUSIONS

Patients with FM have impaired postural control and low balance self-efficacy that are associated with pain, muscle strength, and symptom severity.

CLINICAL REHABILITATION IMPACT

Postural control and balance self-efficacy needs to be assessed in patients with FM and the treatment goals should be the improvement of postural control and balance self-efficacy.

A two-component pre-seeded dermal-epidermal scaffold

We have developed a bilayered dermal-epidermal scaffold for application in the treatment of full-thickness skin defects. The dermal component gels in situ and adapts to the lesion shape, delivering human dermal fibroblasts in a matrix of fibrin and cross-linked hyaluronic acid modified with a cell adhesion-promoting peptide. Fibroblasts were able to form a tridimensional matrix due to material features such as tailored mechanical properties, presence of protease-degradable elements and cell-binding ligands. The epidermal component is a robust membrane containing cross-linked hyaluronic acid and poly-l-lysine, on which keratinocytes were able to attach and to form a monolayer. Amine-aldehyde bonding at the interface between the two components allows the formation of a tightly bound composite scaffold. Both parts of the scaffold were designed to provide cell-type-specific cues to allow for cell proliferation and form a construct that mimics the skin environment.

Gellan gum-hyaluronic acid spongy-like hydrogels and cells from adipose tissue synergize promoting neoskin vascularization

Currently available substitutes for skin wound healing often result in the formation of nonfunctional neotissue. Thus, urgent care is still needed to promote an effective and complete regeneration. To meet this need, we proposed the assembling of a construct that takes advantage of cell-adhesive gellan gum-hyaluronic acid (GG-HA) spongy-like hydrogels and a powerful cell-machinery obtained from adipose tissue, human adipose stem cells (hASCs), and microvascular endothelial cells (hAMECs). In addition to a cell-adhesive character, GG-HA spongy-like hydrogels overpass limitations of traditional hydrogels, such as reduced physical stability and limited manipulation, due to improved microstructural arrangement characterized by pore wall thickening and increased mean pore size. The proposed constructs combining cellular mediators of the healing process within the spongy-like hydrogels that intend to recapitulate skin matrix aim to promote neoskin vascularization. Stable and off-the-shelf dried GG-HA polymeric networks, rapidly rehydrated at the time of cell seeding then depicting features of both sponges and hydrogels, enabled the natural cell entrapment/encapsulation and attachment supported by cell-polymer interactions. Upon transplantation into mice full-thickness excisional wounds, GG-HA spongy-like hydrogels absorbed the early inflammatory cell infiltrate and led to the formation of a dense granulation tissue. Consequently, spongy-like hydrogel degradation was observed, and progressive wound closure, re-epithelialization, and matrix remodelling was improved in relation to the control condition. More importantly, GG-HA spongy-like hydrogels promoted a superior neovascularization, which was enhanced in the presence of human hAMECs, also found in the formed neovessels. These observations highlight the successful integration of a valuable matrix and prevascularization cues to target angiogenesis/neovascularization in skin full-thickness excisional wounds.

Effectiveness of high-frequency transcutaneous electrical nerve stimulation at tender points as adjuvant therapy for patients with fibromyalgia

BACKGROUND

Fibromyalgia is a chronic pain syndrome associated with sleep disorders, fatigue and psychological symptoms. Combinations therapies, such as electrotherapy and therapeutic exercises have been used in the clinical practice.

AIM

To assess the efficacy of high-frequency transcutaneous electrical nerve stimulation (TENS) as an adjuvant therapy to aerobic and stretching exercises, for the treatment of fibromyalgia.

DESIGN

Controlled clinical trial.

SETTING

Unit of rehabilitation of a public hospital.

POPULATION

Twenty-eight women aged 52.4±7.5 years, with fibromyalgia.

METHODS

A visual analogue scale measured pain intensity; tender points pain threshold, by dolorimetry; and quality of life, by the Fibromyalgia Impact Questionnaire. All subjects participated in an eight-week program consisting of aerobic exercises, followed by static stretching of muscle chains. In TENS group, high-frequency (150 Hz) was applied on bilateral tender points of trapezium and supraspinatus.

RESULTS

TENS group had a greater pain reduction (mean change score=-2.0±2.9 cm) compared to Without TENS group (-0.7±3.7 cm). There was a difference between mean change scores of each group for pain threshold (right trapezium: 0.2±1 kg/cm² in TENS group and -0.2±1.2 kg/cm² in Without TENS group). In the evaluation of clinically important changes, patients receiving TENS had relevant improvement of pain, work performance, fatigue, stiffness, anxiety and depression compared to those not receiving TENS.

CONCLUSION

It has suggested that high-frequency TENS as an adjuvant therapy is effective in relieving pain, anxiety, fatigue, stiffness, and in improving ability to work of patients with fibromyalgia.

CLINICAL REHABILITATION IMPACT

High-frequency TENS may be used as a short-term complementary treatment of fibromyalgia.

Adipose stem cell-derived osteoblasts sustain the functionality of endothelial progenitors from the mononuclear fraction of umbilical cord blood

Vascularization is the most pressing issue in tissue engineering (TE) since ensuring that engineered constructs are adequately perfused after in vivo transplantation is essential for the construct's survival. The combination of endothelial cells with current TE strategies seems the most promising approach but doubts persist as to which type of endothelial cells to use. Umbilical cord blood (UCB) cells have been suggested as a possible source of endothelial progenitors. Osteoblasts obtained from human adipose-derived stem cells (hASCs) were co-cultured with the mononuclear fraction of human UCB for 7 and 21 days on carrageenan membranes. The expression of vWF and CD31, and the DiI-AcLDL uptake ability allowed detection of the presence of endothelial and monocytic lineages cells in the co-culture for all culture times. In addition, the molecular expression of CD31 and VE-cadherin increased after 21 days of co-culture. The functionality of the system was assessed after transplantation in nude mice. Although an inflammatory response developed, blood vessels with cells positive for human CD31 were detected around the membranes. Furthermore, the number of blood vessels in the vicinity of the implants increased when cells from the mononuclear fraction of UCB were present in the transplants compared to transplants with only hASC-derived osteoblasts. These results show how endothelial progenitors present in the mononuclear fraction of UCB can be sustained by hASC-derived osteoblast co-culture and contribute to angiogenesis even in an in vivo setting of inflammatory response.

Fibroblasts regulate osteoblasts through gap junctional communication

BACKGROUND AIMS

Fibroblasts are present in most tissues of the body, playing an active role in the regulation of homeostasis in such tissues. While fibroblast heterotypic interactions are acknowledged in the regeneration of tissues such as skin and periodontal ligament, their role in bone regeneration is far from being understood. We hypothesized that fibroblasts could influence osteoblasts, and as connexin 43 is the predominant connexin in both cell types, we speculated that those heterotypic interactions could occur through gap junctional communication (GjC).

METHODS

Direct co-cultures of human mesenchymal stromal cell (hMSC)-derived osteoblasts and human dermal fibroblasts (hDFb) were established in the presence and absence of the GjC inhibitor α-glycyrrhetinic acid. Communication between osteoblasts and hDFb via GjC was verified by transference of the gap junction-permeable dye calcein-AM. Cell proliferation was assessed by dsDNA quantification, while osteogenic differentiation was evaluated by measuring alkaline phosphatase (ALP) activity and the expression of osteogenic markers by real-time polymerase chain reaction (PCR).

RESULTS

The amount of calcein-AM transferred between the different cell types decreased when α-glycyrrhetinic acid was used. While the proliferation of the hMSC-derived osteoblasts was not affected by the presence of the hDFb, the level of osteogenic markers such as ALP activity and osteocalcin in transcripts in osteoblasts was severely diminished. This effect was partially reversed by adding α-glycyrrhetinic acid to the co-cultures.

CONCLUSIONS

The results strongly suggest that fibroblasts regulate osteoblast behavior partially through GjC. This information could be critical for predicting the outcome of strategies aimed at promoting bone regeneration as, for example, in bone tissue-engineering approaches.

Using stem cells in skin regeneration: possibilities and reality

Tissue-engineered skin has a long history of clinical applications, yet current treatments are not capable of completely regenerating normal, uninjured skin. Nonetheless, the field has experienced a tremendous development in the past 10 years, encountering the summit of tissue engineering (TE) and the arising of stem cell research. Since then, unique features of these cells such as self-renewal capacity, multi-lineage differentiation potential, and wound healing properties have been highlighted. However, a realistic perspective of their outcome in skin regenerative medicine applications is still absent. This review intends to discuss the directions that adult and embryonic stem cells (ESCs) can take, strengthening the skin regeneration field. Distinctively, a critical overview of stem cells' differentiation potential onto skin main lineages, along with a highlight of their participation in wound healing mechanisms, is herein provided. We aim to compile and review significant work to allow a better understanding of the best skin TE approaches, enabling the embodiment of the materialization of a new era in skin regeneration to come, with a conscious overview of the current limitations.

Osteogenic differentiation of two distinct subpopulations of human adipose-derived stem cells: an in vitro and in vivo study

The first stem cells considered for the reconstruction of bone were bone marrow mesenchymal stem cells (BMSCs). Subsequently, cells with similar marker expression panel and differentiation potential were found in new sources of cells, such as adipose tissue. This source of stem cells has a promising future in tissue-engineering applications, considering the abundance of this tissue in the human body, the easy harvesting and the high number of stem cells that are available from such a small amount of tissue. The isolation of the adipose stem cells is generally performed by means of enzymatic digestion of the tissues, followed by a natural selection of the stem cells based on their capacity to adhere to the culture flasks, leading to a quite heterogeneous population. This constitutes a major drawback for the use of these cells, since the heterogeneity of the cell culture obtained can compromise their proliferation and differentiation potential. In the present study we have analysed the in vitro and in vivo behaviour of two selected subpopulations with high osteogenic potential. For this purpose, ASCs(CD29+) and ASCs (STRO-1+)subpopulations were isolated and in vitro cultured onto a biodegradable polymeric scaffold, using osteogenic medium, before implantation in a nude mice model. The biodegradable polymeric scaffold used is a fibre-mesh structure based on a blend of starch and polycaprolatone (SPCL) that has been successfully used in several bone tissue-engineering studies. The implanted ASCs-scaffold constructs promoted the formation of new bone tissue in nude mice. However, the results obtained show differences in the behaviour of the two ASCs subpopulations under study, particularly regarding their potential to differentiate into the osteogenic lineage, and allowed the indentification of ASCs (STRO-1+) as the best subpopulation for bone tissue-engineering applications.

Effect of frequency of static stretching on flexibility, hamstring tightness and electromyographic activity

We compared the effect of the number of weekly repetitions of a static stretching program on the flexibility, hamstring tightness and electromyographic activity of the hamstring and of the triceps surae muscles. Thirty-one healthy subjects with hamstring tightness, defined as the inability to perform total knee extension, and shortened triceps surae, defined by a tibiotarsal angle wider than 90 degrees during trunk flexion, were divided into three groups: G1 performed the stretching exercises once a week; G2, three times a week, and G3, five times a week. The parameters were determined before and after the stretching program. Flexibility improved in all groups after intervention, from 7.65 +/- 10.38 to 3.67 +/- 12.08 in G1, from 10.73 +/- 12.07 to 0.77 +/- 10.45 in G2, and from 14.20 +/- 10.75 to 6.85 +/- 12.19 cm in G3 (P < 0.05 for all comparisons). The increase in flexibility was higher in G2 than in G1 (P = 0.018), while G2 and G3 showed no significant difference (G1: 4 +/- 2.17, G2: 10 +/- 5.27; G3: 7.5 +/- 4.77 cm). Hamstring tightness improved in all groups, from 37.90 +/- 6.44 to 29 +/- 11.65 in G1, from 39.82 +/- 9.63 to 21.91 +/- 8.40 in G2, and from 37.20 +/- 6.63 to 26.10 +/- 5.72 degrees in G3 (P < 0.05 for all comparisons). During stretching, a statistically significant difference was observed in electromyographic activity of biceps femoris muscle between G1 and G3 (P = 0.048) and G2 and G3 (P = 0.0009). No significant differences were found in electromyographic activity during maximal isometric contraction. Stretching exercises performed three times a week were sufficient to improve flexibility and range of motion compared to subjects exercising once a week, with results similar to those of subjects who exercised five times a week.

Cell interactions in bone tissue engineering

Bone fractures, where the innate regenerative bone response is compromised, represent between 4 and 8 hundred thousands of the total fracture cases, just in the United States. Bone tissue engineering (TE) brought the notion that, in cases such as those, it was preferable to boost the healing process of bone tissue instead of just adding artificial parts that could never properly replace the native tissue. However, despite the hype, bone TE so far could not live up to its promises and new bottom-up approaches are needed. The study of the cellular interactions between the cells relevant for bone biology can be of essential importance to that. In living bone, cells are in a context where communication with adjacent cells is almost permanent. Many fundamental works have been addressing these communications nonetheless, in a bone TE approach, the 3D perspective, being part of the microenvironment of a bone cell, is as crucial. Works combining the study of cell-to-cell interactions in a 3D environment are not as many as expected. Therefore, the bone TE field should not only gain knowledge from the field of fundamental Biology but also contribute for further understanding the biology of bone. In this review, a summary of the main works in the field of bone TE, aiming at studying cellular interactions in a 3D environment, and how they contributed towards the development of a functional engineered bone tissue, is presented.

Silicon-hydroxyapatite bioactive coatings (Si-HA) from diatomaceous earth and silica. Study of adhesion and proliferation of osteoblast-like cells

The aim of this study consisted on investigating the influence of silicon substituted hydroxyapatite (Si-HA) coatings over the human osteoblast-like cell line (SaOS-2) behaviour. Diatomaceous earth and silica, together with commercial hydroxyapatite were respectively the silicon and HA sources used to produce the Si-HA coatings. HA coatings with 0 wt% of silicon were used as control of the experiment. Pulsed laser deposition (PLD) was the selected technique to deposit the coatings. The Si-HA thin films were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) demonstrating the efficient transfer of Si to the HA structure. The in vitro cell culture was established to assess the cell attachment, proliferation and osteoblastic activity respectively by, Scanning Electron Microscopy (SEM), DNA and alkaline phosphatase (ALP) quantification. The SEM analysis demonstrated a similar adhesion behaviour of the cells on the tested materials and the maintenance of the typical osteoblastic morphology along the time of culture. The Si-HA coatings did not evidence any type of cytotoxic behaviour when compared with HA coatings. Moreover, both the proliferation rate and osteoblastic activity results showed a slightly better performance on the Si-HA coatings from diatoms than on the Si-HA from silica.

Effectiveness of muscle stretching exercises with and without laser therapy at tender points for patients with fibromyalgia

OBJECTIVE

To assess the efficiency of a treatment composed of muscle stretching exercises, associated or not to laser therapy at tender points, for patients with fibromyalgia (FM), in view of bettering their quality of life.

METHODS

Twenty FM patients were randomly assigned to two groups: one submitted to laser therapy and stretching (LSG, n=10), and the other only to stretching exercises (SG, n=10). The visual analog scale of pain (VAS) and dolorimetry at tender points were used to assess pain; life quality was evaluated by means of the Fibromyalgia Impact Questionnaire (FIQ) and the 36-item Short-Form Health Survey (SF-36).

RESULTS

After the treatment program, both in LSG and SG were detected pain reduction, higher pain threshold at tender points (all p<0.01), lower mean FIQ scores, and higher SF-36 mean scores (all p<0.05). No significant differences were found between both groups.

CONCLUSION

The stretching exercises program proposed is efficient to reduce pain and painful sensibility at tender points, thus enhancing patients' quality of life. Laser therapy has not shown advantages when added to muscle stretching exercises.

The effect of starch-based biomaterials on leukocyte adhesion and activation in vitro

Leukocyte adhesion to biomaterials has long been recognised as a key element to determine their inflammatory potential. Results regarding leukocyte adhesion and activation are contradictory in some aspects of the material's effect in determining these events. It is clear that together with the wettability or hydrophilicity/hydrophobicity, the roughness of a substrate has a major effect on leukocyte adhesion. Both the chemical and physical properties of a material influence the adsorbed proteins layer which in turn determines the adhesion of cells. In this work polymorphonuclear (PMN) cells and a mixed population of monocytes/macrophages and lymphocytes (mononuclear cells) were cultured separately with a range of starch-based materials and composites with hydroxyapatite (HA). A combination of both reflected light microscopy and scanning electron microscopy (SEM) was used in order to study the leukocyte morphology. The quantification of the enzyme lactate dehydrogenase (LDH) was used to determine the number of viable cells adhered to the polymers. Cell adhesion and activation was characterised by immunocytochemistry based on the expression of several adhesion molecules, crucial in the progress of an inflammatory response. This work supports previous in vitro studies with PMN and monocytes/macrophages, which demonstrated that there are several properties of the materials that can influence and determine their biological response. From our study, monocytes/macrophages and lymphocytes adhere in similar amounts to more hydrophobic (SPCL) and to moderately hydrophilic (SEVA-C) surfaces and do not preferentially adhere to rougher substrates (SCA). Contrarily, more hydrophilic surfaces (SCA) induced higher PMN adhesion and lower activation. In addition, the hydroxyapatite reinforcement induces changes in cell behaviour for some materials but not for others. The observed response to starch-based biodegradable polymers was not significantly different from the control materials. Thus, the results reported herein indicate the low potential of the starch-based biodegradable polymers to induce inflammation especially the HA reinforced composite materials.

Effect of starch-based biomaterials on the in vitro proliferation and viability of osteoblast-like cells

The cytotoxicity of starch-based polymers was investigated using different methodologies. Poly-L-lactic acid (PLLA) was used as a control for comparison purposes. Extracts of four different starch-based blends (corn starch and ethylene vinyl alcohol (SEVA-C), corn starch and cellulose acetate (SCA), corn starch and polycaprolactone (SPCL) and starch and poly-lactic acid (SPLA70) were prepared in culture medium and their toxicity was analysed. Osteoblast-like cells (SaOs-2) were incubated with the extracts and cell viability was assessed using the MTT test and a lactate dehydrogenase (LDH) assay. In addition DNA and total protein were quantified in order to evaluate cell proliferation. Cells were also cultured in direct contact with the polymers for 3 and 7 days and observed in light and scanning electron microscopy (SEM). LDH and DNA quantification revealed to be the most sensitive tests to assess respectively cell viability and cell proliferation after incubation with starch-based materials and PLLA. SCA was the starch blend with higher cytotoxicity index although similar to PLLA polymer. Cell adhesion tests confirmed the worst performance of the blend of starch with cellulose acetate but also showed that SPCL does not perform as well as it could be expected. All the other materials were shown to present a comparable behaviour in terms of cell adhesion showing slight differences in morphology that seem to disappear for longer culture times. The results of this study suggest that not only the extract of the materials but also their three-dimensional form has to be biologically tested in order to analyse material-associated parameters that are not possible to consider within the degradation extract. In this study, the majority of the starch-based biomaterials presented very promising results in terms of cytotoxicity, comparable to the currently used biodegradable PLLA which might lead the biocompatibility evaluation of those novel biomaterials to other studies.

Surface modification of starch based blends using potassium permanganate-nitric acid system and its effect on the adhesion and proliferation of osteoblast-like cells

The surface modification of three starch based polymeric biomaterials, using a KMnO4/HNO3 oxidizing system, and the effect of that modification on the osteoblastic cell adhesion has been investigated. The rationale of this work is as follows--starch based polymers have been proposed for use as tissue engineering scaffolds in several publications. It is known that in biodegradable systems it is quite difficult to have both cell adhesion and proliferation. Starch based polymers have shown to perform better than poly-lactic acid based materials but there is still room for improvement. This particular work is aimed at enhancing cell adhesion and proliferation on the surface of several starch based polymer blends that are being proposed as tissue engineering scaffolds. The surface of the polymeric biomaterials was chemically modified using a KMnO4/HNO3 system. This treatment resulted in more hydrophilic surfaces, which was confirmed by contact angle measurements. The effect of the treatment on the bioactivity of the surface modified biomaterials was also studied. The bioactivity tests, performed in simulated body fluid after biomimetic coating, showed that a dense film of calcium phosphate was formed after 30 days. Finally, human osteoblast-like cells were cultured on unmodified (control) and modified materials in order to observe the effect of the presence of higher numbers of polar groups on the adhesion and proliferation of those cells. Two of the modified polymers presented changes in the adhesion behavior and a significant increase in the proliferation rate kinetics when compared to the unmodified controls.

Quantifying pain threshold and quality of life of fibromyalgia patients

The most typical symptom of fibromyalgia (FM) is diffuse pain, and pain at specific points-tender points-is crucial for its diagnosis. By comparing healthy individuals and FM patients, this study was aimed at assessing pain and quality of life of Brazilian females with FM, while seeking for a correlation between pain threshold and quality of life. A total of 178 women were evaluated: 124 were FM patients and 54 were healthy women. Pain threshold at tender points was quantified by dolorimetry, and diffuse pain by means of the visual analogue scale (VAS); the Fibromyalgia Impact Questionnaire (FIQ) was used to evaluate quality of life. Statistical treatment of the data allowed for proposing two indexes: a pain threshold index (PT) and a quality of life one (QOL). PT is the lowest value among all pain thresholds measured at the 18 tender points; QOL is the mean of responses to the FIQ and VAS. Both indexes were tested and showed significant differences between the test and control groups. By pairing pain threshold values of each tender point in the test and control groups, it was found that the most sensitive points matched between the two groups, that is, the most sensitive anatomic spots in a healthy individual are also likely to be the most sensitive points in a person with FM. This suggests that a stimulus that provokes slight discomfort to a healthy person may produce more pain in FM patients--which may bear implications for FM clinical treatment. In this sample of Brazilian women, FM patients had both lower pain threshold and worse quality of life than healthy women.

Evaluation of the potential of starch-based biodegradable polymers in the activation of human inflammatory cells

The inflammatory response resulting from the implantation of a medical device may compromise its performance and efficiency leading, in certain cases, to the failure of the implant. Thus, the assessment of the behavior of inflammatory cells in vitro, constitutes a key feature in the evaluation of the adverse potential, or not, of new promising biomaterials. The objectives of this study were to determine whether starch-based polymers and composites activated human neutrophils. Blends of starch with ethylene-vinyl alcohol, with cellulose acetate and polycaprolactone, as well as composites based on all these materials filled with hydroxyapatite have been studied. A lysozyme assay was adapted to examine enzyme secretion from human neutrophils incubated with different starch-based materials. Changes in the free radical and degranulation activity of the neutrophil were also determined by measuring the luminescent response of Pholasin, a photoprotein that emits light after excitation by reactive oxygen species. The amount of lysozyme secreted by neutrophils incubated with the polymers did not exhibit significant differences between the tested materials. Results were in all cases similar to those obtained for the control (polypropylene) except for one of the starch blends (corn starch with polycaprolactone reinforced with 30% (w/w) of HA). The chemiluminescence experiments showed that polymers reduce the signal produced by activated neutrophils. Furthermore, for some polymers it was demonstrated that the phenomenon was due to an effect of the surface of the materials in cell adhesion or a simultaneous competition for the photoprotein in solution, which results in the decrease of the intensity of light emitted and detected.

The biocompatibility of novel starch-based polymers and composites: in vitro studies

Studies with biodegradable starch-based polymers have recently demonstrated that these materials have a range of properties. which make them suitable for use in several biomedical applications, ranging from bone plates and screws to drug delivery carriers and tissue engineering scaffolds. The aim of this study was to screen the cytotoxicity and evaluate starch-based polymers and composites as potential biomaterials. The biocompatibility of two different blends of corn-starch, starch ethylene vinyl alcohol (SEVA-C) and starch cellulose acetate (SCA) and their respective composites with hydroxyapatite (HA) was assessed by cytotoxicity and cell adhesion tests. The MTT assay was performed with the extracts of the materials in order to evaluate the short-term effect of the degradation products. The cell morphology of L929 mouse fibroblast cell line was also analysed after direct contact with polymers and composites for different time periods and the number of cells adhered to the surface of the polymers was determined by quantification of the cytosolic lactate dehydrogenase (LDH) activity. Both types of starch-based polymers exhibit a cytocompatibility that might allow for their use as biomaterials. SEVA-C blends were found to be the less cytotoxic for the tested cell line, although cells adhere better to SCA surface. The cytotoxicity test also revealed that SCA and SEVA-C composites have a similar response to the one obtained for SCA polymer. Scanning electron microscopy (SEM) analysis showed that cells were much more spread on the SCA polymer and LDH measurements showed a higher number of cells on this surface.

A comparative study for results obtained using biomonitors and PM10 collectors in Sado Estuary

In 1996 a program was started, financed by the Environmental Ministry of Portugal and IAEA, aiming to study the inorganic atmospheric pollutant dispersion in Sado Estuary. Gent PM10 air samplers were used for air particulate matter sampling. Three sampling sites were chosen, forming a triangle around the fuel power station of Setúbal. Transplants of Parmelia sulcata Taylor were suspended in nylon bags within a rectangle 15 km wide and 25 km long on a 2.5 x 2.5 km grid. Two sets of four transplants were hung in each of the 47 locations, one set facing the wind and the other set opposing the wind. The transplants were suspended in December 1997 for a 1-year period; every 3 months, one transplant of each set was collected. Both lichen transplants and PM10 filters were analysed by INAA and PIXE. A comparative study of results obtained for the two sampling procedures is presented in this work.

Pain evaluation of patients with fibromyalgia, osteoarthritis, and low back pain

The purpose of this study was to evaluate and compare pain as reported by outpatients with fibromyalgia, osteoarthritis, and low back pain, in view of designing more adequate physical therapy treatment.

PATIENTS AND METHODS

A Portuguese version of the McGill Pain Questionnaire - where subjects are asked to choose, from lists of pre-categorized words, one or none that best describes what they feel - was used to assess pain intensity and quality of 64 patients, of which 24 had fibromyalgia, 22 had osteoarthritis, and 18 had low back pain. The pre-categorized words were organized into 4 major classes - sensory, affective, evaluative, and miscellaneous.

RESULTS

Patients with fibromyalgia reported, comparatively, more intense pain through their choice of pain descriptors, both sensory and affective; they also chose a higher number of words from these classes than patients in the other groups and were the only ones to choose specific affective descriptors such as "vicious", "wretched", "exhausting", "blinding".

CONCLUSION

Assuming that each disease presents unique qualities of pain experience, and that these can be pointed out by means of this questionnaire by patients' choice of specific groups of words, the findings suggest that fibromyalgia include not only a physical component, but also a psycho-emotional component, indicating that they require both emotional/affective and physical care.

Growth deficiency, mental retardation and unusual facies

An 8-year-old girl with growth deficiency, mental retardation, unusual facies and hypertrichosis is described. The case is compared with one described by Wiedemann et al. [(1989) Atlas of Clinical Syndromes, 2nd ed. London: Wolfe Publishing pp. 198-199].

Environmental assessment in an industrial area of Portugal

The region of Lisbon and south of Lisbon (Sado estuary) is densely industrialized, and, therefore, air pollution should be studied in a more detailed scale there. The topography of the Sado estuary region and the predominant wind direction from the northwest contribute to the influence in this region of the industries located in the north. The region selected includes a fuel-fired power station. Transplants of the lichen Parmelia sulcata Taylor were suspended in nylon bags within a rectangle 15 km wide and 25 km long on a grid 2.5 km x 2.5 km, centered in the power station. In each of the 47 sites, 2 sets of 4 transplants each were hung. Care was taken (1) in covering the two sets with a polyethylene roof to prevent leaching of elements in the lichen, (2) in building a hanging system that could rotate according to the wind direction, and (3) in orienting one set toward the wind and the other set opposite the wind. For a 1-yr period and every 3 mo, one transplant of each set is collected. In this work, the results of the first campaign (after 3 mo suspension) obtained by instrumental neutron activation analysis and proton-induced X-ray emission are shown. Some elemental contents are mapped and discussed.

Comparison between enzyme-linked immunosorbent assay, indirect fluorescent antibody and rapid conglutination tests in detecting antibodies against Babesia bovis

The performance of an enzyme-linked immunosorbent assay (ELISA), an indirect fluorescent antibody test (IFAT) and a rapid conglutination test (RCT) for the detection of antibodies against Babesia bovis, was evaluated with 462 cattle sera from Bahia State; Brazil. The results showed a concordance of 96.6% between the ELISA and IFAT, 90.5% between the ELISA and RCT, and 91.8% between the IFAT and RCT. Although the prevalence rates determined by ELISA (97.2%) and IFAT (96.8%) were higher than that indicated by the RCT (92.9%), performances of the three serological tests were very similar and characterized the region studied as enzootically stable to B. bovis.

Erythrophagocytosis in the caprine trophoblast

The mechanism of iron transfer by extravasation of maternal blood in the maternal-fetal interface and the subsequent phagocytosis of the erythrocytes by the trophoblast cells was described in ovine, bovine and other species. This research was performed due to the absence of studies on this process in the goat. Fragments of placentomes were obtained from 9 adult goats of an unspecified breed and were separated into Groups A, B and C, based on 90, 120 and 150 d of gestation, respectively. Fragments of 3 placentomes were obtained from each animal of all groups. The first of them was removed from the base, the second from the middle part and the third from the end of the gestational uterine horn. The fragments were fixed in Bouin solution and histologically processed according to the usual paraffin inclusion techniques. The slides were stained by hematoxilin-eosin and potassium ferrocyanide and examined under light microscopy The erythrophagocytosis (EP) process of the trophoblast was identified in all the examined histological sections, throughout the gestation and for each placentome. An accumulation of spots of blood was observed only in the maternal-fetal interface located in the arcade zone of the placentome. The main cells of the trophoblast of these areas presented an intense phagocytic activity and the observation of erythrocytes with hemossiderin pigments in their citoplasm was possible. The trophoblast epithelium of these areas was thicker and with a columnar aspect than the cubic aspect observed in other areas. The trophoblast binucleate cells do not seem to participate in EP. Our findings indicate that the phagocitosis process of the maternal erythrocites by the trophoblast also occurs in caprine species, indicating that this could be a mechanism of transplacentary transfer of iron in this species.

[Severe combined immunodeficiency: description of a clinical case]

A Severe Combined Immunodeficiency (SCID) is a rare disease, with recessive autosomic or X linked inheritance. The clinical phenotype is related to the defect of specific antigen response. The authors describe a patient presenting recurrent infections, affected by SCID, with multiple hospitalizations. Immunologic evaluation was performed and adenosine deaminase deficiency was excluded. The patient was submitted to herniography and he died seven days after the surgery. The preparation for bone marrow transplantation was provided. The anatomo-pathological findings had showed immunologic system alterations. The early clinical diagnosis and the therapy are discussed.

Nutrient intake and dental caries in the primary dentition

An extensive literature has assessed the influence of diet on dental caries, but to date dietary influences on caries of the primary dentition have not been studied widely. This study examined the role of specific nutrients in the caries experience of preschool children. A total of 628 children ages 2 to 6 years received a dental examination, parent interview, and a seven-day diet diary. The diary was completed adequately for 269 children (43%). The average daily intakes of 15 nutrients were computed and compared with recommended dietary allowances (RDA); total sugar consumption and Ca/P ratio were calculated. Each child's gender, age, fluoride history, previous dental experience, and nutrient intakes were examined as independent variables. Stepwise logistic regression showed the combination of categories most predictive of caries was older age, suboptimal fluoride consumption, and recall dental visit. No association was apparent between dental caries and the intake of specific nutrients, total sugar consumption, or Ca/P ratio.

Intraoral etiology of a life-threatening infection in an immunocompromised patient: report of case

Oral infections are one of the major causes of morbidity and mortality in patients with hematologic malignancies. Total body irradiation and chemotherapy suppress the ability of the immune system to respond to the more virulent pathogens that can attack the compromised patient. The case of an 8.5-year-old girl is reported, in which an oral infection and a clinically observed motility resulted in a communication with the submandibular space; a significant hard, brawny edema of her right submandibular area resulted. Surgery, strict oral hygiene, and regular irrigation with a chlorhexidine gluconate solution resulted in successful healing.

Steroid synthesis by the fetal part of the bovine placenta of late pregnancy in vitro: Effect of a low dose of dexamethasone in vivo

Pregnant cows were treated with 5 mg dexamethasone (DEX) (n = 5) or 0.9% saline (n = 3) on Day 255 of gestation. Placentomes were removed on Day 250, Day 260 by laparotomy, and immediately after parturition. Fetal placental tissue (500 mg) was homogenized and frozen for the determination of initial tissue content of progesterone (P(4)) and estrone (E(1)) by radioimmunoassay (RIA). Tissue samples (500 mg) were incubated for 1, 5, or 9 h in the presence of 0, 10, or 100 ng/ml androstenedione (A) or pregnenolone (P(5)). After incubation, tissue was homogenized in the incubation medium (HOM) and P(4) and E(1) content assessed by RIA. Finally, tissue was incubated in medium containing (3)H-A or (3)H-P(5) with or without cortisol (70 ng/ml) to measure conversion of precursors into estrogens (E). Overall initial tissue concentration of P(4) decreased as pregnancy progressed (P < 0.05). An interaction between DEX treatment and stage of gestation (P < 0.05) indicated that P(4) decreased only in tissue from DEX-treated cows, whereas P(4) in tissue from control cows remained constant. Tissue concentrations of E(1) increased from Day 250 to parturition (P < 0.05) and were not influenced by in vivo DEX treatment. Progesterone concentration in HOM increased during incubation indicating P(4) synthesis (P < 0.001). Addition of 100 ng/ml P(5) stimulated P(4) production (P < 0.05). There was a larger increase in P(4) in HOM from DEX-treated cows than in HOM from control cows (P < 0.05). Concentration of E(1) decreased during incubation (P < 0.0001) and was not influenced by the addition of A or P(5). Estrogen synthesis was indicated by the conversion of A or P(5) into E (pmol/g/h). The conversion of precursors (A or P(5)) into E increased during gestation and was not influenced by in vivo DEX treatment. Cortisol application in vitro did not affect E synthesis. It is concluded that treatment with 5 mg DEX in vivo on Day 255 of pregnancy does not seem to influence placental E synthesis in vitro. However, the decrease in initial P(4) tissue concentration and the increase in P(4) synthesis by fetal placental tissue from DEX-treated cows in vitro suggest that DEX treatment in vivo stimulates P(4) synthesis with increased metabolism of P(4) into other metabolites.