Interventions Developed with the Intervention Mapping Protocol in Work Disability Prevention: A Systematic Review of the Literature.

Purposes Intervention mapping (IM) is a protocol for developing effective behavior change interventions. It has been used for 10 years to develop work disability prevention (WDP) interventions, but it is not known to what extent and with what success. The main objective of this study was to review the effectiveness of these interventions. Secondary objectives were to review their fidelity to the IM protocol, their theoretical frameworks and their content. Methods A search strategy was conducted in MEDLINE, Web of Science, PsycINFO, Pascal, Francis, and BDSP. All titles and abstracts were reviewed. A standardized extraction form was developed. All included studies were reviewed by two reviewers blinded to each other. Results Eight WDP interventions were identified aimed at return to work (RTW; n = 6) and self-management at work (n = 2). RTW interventions targeted workers with stress-related mental disorders (n = 1), low back pain (n = 1), musculoskeletal disorders (n = 1), cancer (n = 2) and gynecological surgery (n = 1). The fidelity to the IM protocol was weaker for the participatory planning group. Matrices of change, change methods, and applications were systematically reported. The main theoretical frameworks used were the attitude-social influence-self efficacy model (n = 4) and the theory of planned behavior (n = 2). Half of the interventions included a workplace component (n = 4). Two interventions were reported as effective, and one partially effective. Conclusion The IM protocol is used in WDP since 2007. The participative dimension appears underused. Few theoretical frameworks were used. Implications are to better consider the stakeholders involvement, and mobilize theoretical frameworks with greater attempts to intervene on the work environment.

[Isolated gallbladder agenesis mimicking biliary colic: A difficult preoperative diagnosis]. / Coliques hépatiques révélant une agénésie de la vésicule biliaire : un diagnostic préopératoire difficile.

Isolated gallbladder agenesis is a very rare and unrecognized congenital anomaly. Patients are usually asymptomatic, but 23% present with symptoms suggestive of biliary colic. Ultrasound investigation often fails to diagnose this malformation, misinterpreted as scleroatrophic gallbladder, leading to unnecessary and potentially dangerous surgery. We report on a case of a 9-year-old child who complained of biliary colic. Ultrasound showed a possible scleroatrophic gallbladder. This diagnosis was in doubt, however, because the patient had no previous history of cholecystitis. Finally, magnetic resonance cholangiopancreatography failed to show any gallbladder. The absence of the visualization of the gallbladder in a context of right upper quadrant pain should suggest gallbladder agenesis. Pain can be explained by the so-called postcholecystectomy syndrome.

Pharmacological Inhibition of PKCθ Counteracts Muscle Disease in a Mouse Model of Duchenne Muscular Dystrophy.

Inflammation plays a considerable role in the progression of Duchenne Muscular Dystrophy (DMD), a severe muscle disease caused by a mutation in the dystrophin gene. We previously showed that genetic ablation of Protein Kinase C θ (PKCθ) in mdx, the mouse model of DMD, improves muscle healing and regeneration, preventing massive inflammation. To establish whether pharmacological targeting of PKCθ in DMD can be proposed as a therapeutic option, in this study we treated young mdx mice with the PKCθ inhibitor Compound 20 (C20). We show that C20 treatment led to a significant reduction in muscle damage associated with reduced immune cells infiltration, reduced inflammatory pathways activation, and maintained muscle regeneration. Importantly, C20 treatment is efficient in recovering muscle performance in mdx mice, by preserving muscle integrity. Together, these results provide proof of principle that pharmacological inhibition of PKCθ in DMD can be considered an attractive strategy to modulate immune response and prevent the progression of the disease. RESEARCH IN CONTEXT: Duchenne muscular dystrophy (DMD) is a severe muscle disease affecting 1:3500 male births. DMD is caused by a mutation in dystrophin gene, coding for a protein required for skeletal and cardiac muscle integrity. Lack of a functional dystrophin is primarily responsible for the muscle eccentric contraction-induced muscle damage, observed in dystrophic muscle. However, inflammation plays a considerable role in the progression of DMD. Glucocorticoids, which have anti-inflammatory properties, are being used to treat DMD with some success; however, long term treatment with these drugs induces muscle atrophy and wasting, outweighing their benefit. The identification of specific targets for anti-inflammatory therapies is one of the ongoing therapeutic options. Although blunting inflammation would not be a "cure" for the disease, the emerging clue is that multiple strategies, addressing different aspects of the pathology, which may eventually converge, may be successful. In this context, we previously showed that genetic ablation of Protein Kinase C θ (PKCθ), an enzyme known to be involved in immune response, in mdx, the mouse model of DMD, improves muscle healing and regeneration, preventing massive inflammation. To establish whether pharmacological targeting of PKCθ in DMD can be proposed as a therapeutic option, in this study we treated young mdx mice with the PKCθ inhibitor Compound 20 (C20). We show that C20 treatment led to a significant reduction in muscle damage associated with reduced immune cells infiltration, reduced inflammatory pathways activation, and maintained muscle regeneration. Importantly, C20 treatment is efficient in recovering muscle performance in mdx mice, by preserving muscle integrity. Together, these results provide proof of principle that pharmacological inhibition of PKCθ in DMD can be considered an attractive strategy to modulate immune response and prevent the progression of the disease.

Platinum(iv) N-heterocyclic carbene complexes: their synthesis, characterisation and cytotoxic activity.

Platinum(ii) N-heterocyclic carbene complexes have been oxidized by bromine or iodobenzene dichloride to provide the fully characterised corresponding platinum(iv) NHC complexes. Antiproliferative activities of Pt(iv) NHC complexes were assayed against several cancer cell lines and the results were correlated with respect to their stability. Mechanistic investigations revealed that mitochondrial dysfunction and ROS production were associated with the cytotoxic process induced by these compounds.

[The intervention mapping protocol: A structured process to develop, implement and evaluate health promotion programs]. / Le protocole de l'intervention mapping : un processus méthodique pour élaborer, implanter et évaluer des programmes en promotion de la santé.

BACKGROUND: Health promotion programs are expected to improve population health and reduce social inequalities in health. However, their theoretical foundations are frequently ill-defined, and their implementation faces many obstacles. The aim of this article is to describe the intervention mapping protocol in health promotion programs planning, used recently in several countries. METHODS: The challenges of planning health promotion programs are presented, and the six steps of the intervention mapping protocol are described with an example. Based on a literature review, the use of this protocol, its requirements and potential limitations are discussed. RESULTS: The intervention mapping protocol has four essential characteristics: an ecological perspective (person-environment), a participative approach, the use of theoretical models in human and social sciences and the use of scientific evidence. It comprises six steps: conduct a health needs assessment, define change objectives, select theory-based change techniques and practical applications, organize techniques and applications into an intervention program (logic model), plan for program adoption, implementation, and sustainability, and generate an evaluation plan. This protocol was used in different countries and domains such as obesity, tobacco, physical activity, cancer and occupational health. Although its utilization requires resources and a critical stance, this protocol was used to develop interventions which efficacy was demonstrated. CONCLUSION: The intervention mapping protocol is an integrated process that fits the scientific and practical challenges of health promotion. It could be tested in France as it was used in other countries, in particular to reduce social inequalities in health.

Protein kinase Cθ is required for cardiomyocyte survival and cardiac remodeling.

Protein kinase Cs (PKCs) constitute a family of serine/threonine kinases, which has distinguished and specific roles in regulating cardiac responses, including those associated with heart failure. We found that the PKCθ isoform is expressed at considerable levels in the cardiac muscle in mouse, and that it is rapidly activated after pressure overload. To investigate the role of PKCθ in cardiac remodeling, we used PKCθ(-/-) mice. In vivo analyses of PKCθ(-/-) hearts showed that the lack of PKCθ expression leads to left ventricular dilation and reduced function. Histological analyses showed a reduction in the number of cardiomyocytes, combined with hypertrophy of the remaining cardiomyocytes, cardiac fibrosis, myofibroblast hyper-proliferation and matrix deposition. We also observed p38 and JunK activation, known to promote cell death in response to stress, combined with upregulation of the fetal pattern of gene expression, considered to be a feature of the hemodynamically or metabolically stressed heart. In keeping with these observations, cultured PKCθ(-/-) cardiomyocytes were less viable than wild-type cardiomyocytes, and, unlike wild-type cardiomyocytes, underwent programmed cell death upon stimulation with α1-adrenergic agonists and hypoxia. Taken together, these results show that PKCθ maintains the correct structure and function of the heart by preventing cardiomyocyte cell death in response to work demand and to neuro-hormonal signals, to which heart cells are continuously exposed.

Bisperoxovanadium, a phospho-tyrosine phosphatase inhibitor, reprograms myogenic cells to acquire a pluripotent, circulating phenotype.

Satellite cells are the main source of myogenic progenitors in postnatal skeletal muscle, but their use in cell therapy for muscle disorders is limited because these cells cannot be delivered through circulation and they are rapidly exhausted in severe myopathies. The search for alternative donor cells is ongoing, but none of the candidates so far show all the features required for successful colonization and repair of diseased muscle. In this study, we show that bisperoxovanadium, a phospho-tyrosine phosphatase inhibitor, induces myogenic cells to acquire a gene expression profile and a differentiation potential consistent with the phenotype of a circulating precursors, while maintaining their myogenic potential. These effects are mediated, at least in part, by NF-kappaB activation through the Tyr42-IkappaB-alpha phosphorylation, as shown by the expression of the dominant negative mutant form of the p50 NF-kappaB subunit. Moreover, when bisperoxovanadium-treated cells are injected into the femoral artery of alpha-sarcoglican null dystrophic mice, they are able to circulate and to reach muscle tissue; importantly, they contribute to muscle regeneration, as shown by the expression of alpha-sarcoglican in some fibers. Our observations indicate that bisperoxovanadium, or similar compounds, may prove very valuable to obtain and to expand, from committed cells, multipotent cell populations suitable for gene-cell therapy applications and may help to understand the molecular basis of genome reprogramming and "stem-ness."

Protein kinase C theta co-operates with calcineurin in the activation of slow muscle genes in cultured myogenic cells.

Adult skeletal muscle fibers can be divided into fast and slow twitch subtypes on the basis of specific contractile and metabolic properties, and on distinctive patterns of muscle gene expression. The calcium, calmodulin-dependent protein phosphatase, calcineurin, stimulates slow fiber-specific genes (myoglobin (Mb), troponin I slow) in cultured skeletal muscle cells, as well as in transgenic mice, through the co-operation of peroxisome-proliferation-activator receptor gamma co-activator 1alpha (PGC1alpha) myocyte enhancer factor 2 (MEF2), and nuclear factor of activated T cells (NFAT) transcription factors. Specific protein kinase C isoforms have been shown to functionally co-operate with calcineurin in different cellular models. We investigated whether specific protein kinase C isoforms are involved in calcineurin-induced slow skeletal muscle gene expression. By pharmacological inhibition or exogenous expression of mutant forms, we show that protein kinase C theta (the protein kinase C isoform predominantly expressed in skeletal muscle) is required and co-operates with calcineurin in the activation of the Mb promoter, as well as in the induction of slow isoforms of myosin and troponin I expression, in cultured muscle cells. This co-operation acts primarily regulating MEF2 activity, as shown by using reporter gene expression driven by the Mb promoter mutated in the specific binding sites. MEF2 activity on the Mb promoter is known to be dependent on both PGC1alpha and inactivation of histone deacetylases (HDACs) activity. We show in this study that protein kinase C theta is required for, even though it does not co-operate in, PGC1alpha-dependent Mb activation. Importantly, protein kinase C theta regulates the HDAC5 nucleus/cytoplasm location. We conclude that protein kinase C theta ensures maximal activation of MEF2, by regulating both MEF2 transcriptional complex formation and HDACs nuclear export.

Health-related interests of Georgian adolescents.

The aim of the study was to find out what adolescents in Georgia would like to know about health. Pupils of 6-10 grades (11-17 years old) (n=524) of the focus schools (secondary schools where FRESH program is being implemented) were investigated. A method of participatory research (so called social anthropologic approach) was applied. The study was anonymous. It yielded 3756 questions in total. The questions dedicated to health-related issues made up 36.8% for group I (11-13y.o.), 45,75% for group II (14-17y.o.), 40.5% -- total. The interest in different somatic and psychological problems and diseases was the same in both age groups (14,3%). Interest in sexual items was higher in later adolescents (group I -- 10.58+/-0.66%, group II -- 14.97+/-0.90%, p<0.05). Girls have shown more interest in diseases and common medical problems (M -- 27.3+/-3.2%, F - 45.2+/-2.6%; p<0.05). Boys were more interested in sexual behavior (M -- 40.2+/-3.6%, F -- 25.2+/-2.3%; p<0.05). There was shown a purposefullness of applied research methodology.

Production of compound A and carbon monoxide in circle systems: an in vitro comparison of two carbon dioxide absorbents.

Two new generation carbon dioxide absorbents, DrägerSorb Free and Amsorb Plus, were studied in vitro for formation of compound A or carbon monoxide, during minimal gas flow (500 ml x min(-1)) with sevoflurane or desflurane. Compound A was assessed by gas chromatography/mass spectrometry and carbon monoxide with continuous infrared spectrometry. Fresh and dehydrated absorbents were studied. Mean (SD) time till exhaustion (inspiratory carbon dioxide concentration >or= 1 kPa) with fresh absorbents was longer with DrägerSorb Free (1233 (55) min) than with Amsorb Plus (1025 (55) min; p < 0.01). For both absorbents, values of compound A were < 1 ppm and therefore below clinically significant levels, but were up to 0.25 ppm higher with DrägerSorb Free than with Amsorb Plus. Using dehydrated absorbents, values of compound A were about 50% lower than with fresh absorbents and were identical for DrägerSorb Free and Amsorb Plus. With dehydrated absorbents, no detectable carbon monoxide was found with desflurane.

Compound A production from sevoflurane is not less when KOH-free absorbent is used in a closed-circuit lung model system.

In an in vitro study, less compound A was formed when a KOH-free carbon dioxide absorbent was used. To confirm this observation we used a lung model in which carbon dioxide was fed in at 160 ml min(-1) and sampling gas was taken out for analysis at 200 ml min(-1); ventilation aimed for a PE'CO2 of 5.4 kPa. The soda lime canister temperatures in the inflow and outflow ports (Tin and Tout) were recorded. In six runs of 240 min each, a standard soda lime, Sodasorb (Grace, Epernon, France) was used and in eight runs KOH-free Sofnolime (Molecular Products, Thaxted, UK) was used. Liquid sevoflurane was injected using a syringe pump to obtain 2.1% E'. Compound A was measured by capillary gas chromatography combined with mass spectrometry. Median (range) compound Ainsp increased to a maximum of 22.7 (7.9) ppm for Sodasorb and 33.1 (20) for Sofnolime at 60 min and decreased thereafter; the difference between groups was significant (P<0.05) at each time of analysis up to 240 min. The canister temperatures were similar in both groups and increased to approximately 40 degrees C at 240 min. Contrary to expectation, compound A concentrations were greater with the KOH-free absorbent despite similar canister temperatures with both absorbents.

Only carbon dioxide absorbents free of both NaOH and KOH do not generate compound A during in vitro closed-system sevoflurane: evaluation of five absorbents.

BACKGROUND: Insufficient data exist on the production of compound A during closed-system sevoflurane administration with newer carbon dioxide absorbents. METHODS: A modified PhysioFlex apparatus (Dräger, Lübeck, Germany) was connected to an artificial test lung (inflow at the top of the bellow approximately/= 160 ml/min CO2; outflow at the Y piece of the lung model approximately/= 200 ml/min, simulating oxygen consumption). Ventilation was set to obtain an end-tidal carbon dioxide partial pressure of approximately 40 mmHg. Various fresh carbon dioxide absorbents were used: Sodasorb (n = 6), Sofnolime (n = 6), and potassium hydroxide (KOH)-free Sodasorb (n = 7), Amsorb (n = 7), and lithium hydroxide (n = 7). After baseline analysis, liquid sevoflurane was injected into the circuit by syringe pump to obtain 2.1% end-tidal concentration for 240 min. At baseline and at regular intervals thereafter, end-tidal carbon dioxide partial pressure, end-tidal sevoflurane concentration, and canister inflow (T degrees(in)) and canister outflow (T degrees(out)) temperatures were measured. To measure compound Ainsp concentration in the inspired gas of the breathing circuit, 2-ml gas samples were taken and analyzed by capillary gas chromatography plus mass spectrometry. RESULTS: The median (minimum-maximum) highest compound Ainsp concentrations over the entire period were, in decreasing order: 38.3 (28.4-44.2)* (Sofnolime), 30.1 (23.9-43.7) (KOH-free Sodasorb), 23.3 (20.0-29.2) (Sodasorb), 1.6 (1.3-2.1)* (lithium hydroxide), and 1.3 (1.1-1.8)* (Amsorb) parts per million (*P < 0.01 vs. Sodasorb). After reaching their peak concentration, a decrease for Sofnolime, KOH-free Sodasorb, and Sodasorb until 240 min was found. The median (minimum-maximum) highest values for T degrees(out) were 39 (38-40), 40 (39-42), 41 (40-42), 46 (44-48)*, and 39 (38-41) degrees C (*P < 0.01 vs. Sodasorb), respectively. CONCLUSIONS: With KOH-free (but sodium hydroxide [NaOH]-containing) soda limes even higher compound A concentrations are recorded than with standard Sodasorb. Only by eliminating KOH as well as NaOH from the absorbent (Amsorb and lithium hydroxide) is no compound A produced.

Quantitative determination of vapor-phase compound A in sevoflurane anesthesia using gas chromatography-mass spectrometry.

BACKGROUND: During low-flow or closed-circuit anesthesia with the fluorinated inhalation anesthetic sevoflurane, compound A, an olefinic degradation product with known nephrotoxicity in rats, is generated on contact with alkaline CO(2) adsorbents. To evaluate compound A formation and thus potential sevoflurane toxicity, a reliable and reproducible assay for quantitative vapor-phase compound A determination was developed. METHODS: Compound A concentrations were measured by fully automated capillary gas chromatography-mass spectrometry with cryofocusing. Calibrators of compound A in the vapor phase were prepared from liquid volumetric dilutions of stock solutions of compound A and sevoflurane in ethyl acetate. 1,1,1-Trifluoro-2-iodoethane was chosen as an internal standard. The resulting quantitative method was fully validated. RESULTS: A linear response over a clinically useful concentration interval (0.3-75 microL/L) was obtained. Specificity, sensitivity, and accuracy conformed with current analytical requirements. The CVs were 4.1-10%, the limit of detection was 0.1 microL/L, and the limit of quantification was 0.3 microL/L. Analytical recoveries were 100.6% +/- 10.1%, 102.5% +/- 7.3%, and 99.0% +/- 4.1% at 0.5, 10, and 75 microL/L, respectively. The method described was used to determine compound A concentrations during simulated closed-circuit conditions. Some of the resulting data are included, illustrating the practical applicability of the proposed analytical approach. CONCLUSIONS: A simple, fully automated, and reliable quantitative analytical method for determination of compound A in air was developed. A solution was established for sampling, calibration, and chromatographic separation of volatiles in an area complicated by limited availability of sample volume and low concentrations of the analyte.

Fatal 4-MTA intoxication: development of a liquid chromatographic-tandem mass spectrometric assay for multiple matrices.

The case history and toxicological findings of an overdose fatality involving 4-methylthioamphetamine (4-MTA) and 3,4-methylenedioxymethamphetamine (MDMA) are reported along with a description of the analytical method. Detection and quantitation of 4-MTA and MDMA were performed by liquid chromatography-tandem mass spectrometry using phentermine as internal standard. Application of this technique to a variety of matrices allowed an insight in the distribution of 4-MTA. Several blood samples including femoral vein blood (5.23 mg/L), urine (95.5 mg/L), vitreous humor (1.31 mg/L), bile (36.4 mg/L), and numerous tissue samples such as liver (30.8 mg/kg), spleen (4.10 mg/kg), and frontal lobe (31.7 mg/kg) were assayed. These values indicated that 4-MTA could be identified as the cause of this fatality, whereas the concentrations of MDMA, also described, are less important because the concentrations found are lower. This case reports, for the first time, an extensive toxicological analysis of 4-MTA, by which the data presented may shed some light on the distribution of 4-MTA.

Determination, diversification and multipotency of mammalian myogenic cells.

In amniotes, myogenic commitment appears to be dependent upon signaling from neural tube and dorsal ectoderm, that can be replaced by members of the Wnt family and by Sonic hedgehog. Once committed, myoblasts undergo different fates, in that they can differentiate immediately to form the myotome, or later to give rise to primary and secondary muscle fibers. With fiber maturation, satellite cells are first detected; these cells contribute to fiber growth and regeneration during post-natal life. We will describe recent data, mainly from our laboratory, that suggest a different origin for some of the cells that are incorporated into the muscle fibers during late development. We propose the possibility that these myogenic cells are derived from the vasculature, are multi-potent and become committed to myogenesis by local signaling, when ingressing a differentiating muscle tissue. The implications for fetal and perinatal development of the whole mesoderm will also be discussed.

In vitro compound A formation in a computer-controlled closed-circuit anesthetic apparatus. Comparison with a classical valve circuit.

BACKGROUND: Few data exist on compound A during sevoflurane anesthesia when using closed-circuit conditions and sodalime with modern computer-controlled liquid injection. METHODS: A PhysioFlex apparatus (Dräger, Lübeck, Germany) was connected to an artificial test lung (inflow approximately 160 ml/min carbon dioxide, outflow approximately 200 ml/min, simulating oxygen consumption). Ventilation was set to obtain an end-tidal carbon dioxide partial pressure (Petco2) approximately 40 mmHg. Canister inflow (T degrees in) and outflow (T degrees out) temperatures were measured. Fresh sodalime and charcoal were used. After baseline analysis, sevoflurane concentration was set at 2.1% end-tidal for 120 min. At baseline and at regular intervals thereafter, Petco2, end-tidal sevoflurane, T degrees in, and T degrees out were measured. For inspiratory and expiratory compound A determination, samples of 2-ml gas were taken. These data were compared with those of a classical valve-containing closed-circuit machine. Ten runs were performed in each set-up. RESULTS: Inspired compound A concentrations increased from undetectable to peak at 6.0 (SD 1.3) and 14.3 (SD 2.5) ppm (P < 0.05), and maximal temperature in the upper outflow part of the absorbent canister was 24.3 degrees C (SD 3.6) and 39.8 degrees C (SD 1.2) (P < 0.05) in the PhysioFlex and valve circuit machines, respectively. Differences between the two machines in compound A concentrations and absorbent canister temperature at the inflow and outflow regions were significantly different (P < 0.05) at all times after 5 min. CONCLUSION: Compound A concentrations in the high-flow (70 l/min), closed-circuit PhysioFlex machine were significantly lower than in conventional, valve-based machines during closed-circuit conditions. Lower absorbent temperatures, resulting from the high flow, appear to account for the lower compound A formation.

Toxic effects and bioaccumulation of cadmium in the aquatic oligochaete Tubifex tubifex.

Although Tubifex tubifex (Oligochaeta, Tubificida) has been proposed as a test organism for ecotoxocological studies, very few data concerning sublethal toxicity and bioaccumulation are available on this worm. The aims of this work were to assess the toxicity of cadmium, one of the most toxic metals frequently encountered in polluted areas, on T. tubifex and the ability of the worm to accumulate this metal. Acute toxicity was analyzed by measurement of the 96-h LC(50) and daily survival rates. Results indicated that T. tubifex undergoes an adaptation period to Cd, the duration of which decreases with increasing Cd concentration. The various parameters affecting toxicity are discussed. Sublethal toxicity was studied by scanning electron microscopy. Observations revealed that Cd induced autotomy of the caudal region and mucus production. Autotomy is proposed as a criterion for sublethal toxicity. The results of bioaccumulation studies revealed that Cd is highly and rapidly taken up by the worm, suggesting involvement of efficient detoxification mechanisms. Consequently, the ability to accumulate large amounts of Cd may represent a potential toxicological risk to predators of the worm if Cd is accumulated in bioavailable forms.

TGF-beta autocrine loop regulates cell growth and myogenic differentiation in human rhabdomyosarcoma cells.

Transforming growth factor beta (TGF) is a well-known inhibitor of myogenic differentiation as well as an autocrine product of rhabdomyosarcoma cells. We studied the role of the TGF-beta autocrine loop in regulating growth and myogenic differentiation in the human rhabdomyosarcoma cell line, RD. We previously reported that the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) induces growth arrest and myogenic differentiation in these cells, which constitutively express muscle regulatory factors. We show that TPA inhibits the activation of secreted latent TGF-beta, thus decreasing the concentration of active TGF-beta to which the cells are exposed. This event is mediated by the TPA-induced alteration of the uPA/PAI serine-protease system. Complete removal of TGF-beta, mediated by the ectopic expression of a soluble type II TGF-beta receptor dominant negative cDNA, induces growth arrest, but does not trigger differentiation. In contrast, a reduction in the TGF-beta concentration, to a range of 0.14-0.20 x 10(-2) ng/ml (which is similar to that measured in TPA-treated cells), mimics TPA-induced differentiation. Taken together, these data demonstrate that cell growth and suppression of differentiation in rhabdomyosarcoma cells require overproduction of active TGF-beta; furthermore, they show that a 'critical' concentration of TGF-beta is necessary for myogenic differentiation to occur, whereas myogenesis is abolished below and above this concentration. By impairing the TGF-beta autocrine loop, TPA stabilizes the factor concentration within the range compatible for differentiation to occur. In contrast, in human primary muscle cells a much higher concentration of exogenous TGF-beta is required for the differentiation inhibitory effect and TPA inhibits differentiation in these cells probably through a TGF-beta independent mechanism. These data thus clarify the mechanism underlying the multiple roles of TGF-beta in the regulation of both the transformed and differentiated phenotype.

Isolation and characterization of the murine zinc finger coding gene, ZT2: expression in normal and transformed myogenic cells.

In the context of a project aimed at the identification of zinc finger proteins involved in skeletal muscle histogenesis and differentiation, we isolated a murine gene, named ZT2. The 2.44kb partial cDNA clone corresponds to the 3' region of the gene, and contains a 0.54kb open reading frame encoding four C2H2-like zinc finger domains, organized in tandem. This cDNA hybridizes with multiple transcripts (2, 4.5 and 7kb), whose expression levels vary in different tissues and at different developmental stages in the same tissue. At least in skeletal muscle we observed differences in the polyadenylation state of the transcripts at different stages of development. Moreover, ZT2 expression is correlated with cell proliferation and transformation. Sequence analysis and genetic mapping indicate that ZT2 is the homologue of ZNF125, one of the linked zinc finger encoding genes localized on human Chr 11q23. In humans, a high frequency of tumor-associated translocations is found in this chromosome region. As expected, ZT2 maps to the corresponding region on chromosome 9 in the mouse.