Mitochondrial inhibitors activate influx of external Ca2+ in sea urchin sperm

AbstractSea urchin sperm have a single mitochondrion which, aside from its main ATP generating function, may regulate motility, intracellular Ca2+ concentration ([Ca2+]i) and possibly the acrosome reaction (AR). We have found that acute application of agents that inhibit mitochondrial function via differing mechanisms (CCCP, a proton gradient uncoupler, antimycin, a respiratory chain inhibitor, oligomycin, a mitochondrial ATPase inhibitor and CGP37157, a Na+/Ca2+ exchange inhibitor) increases [Ca2+]i with at least two differing profiles. These increases depend on the presence of extracellular Ca2+, which indicates they involve Ca2+ uptake and not only mitochondrial Ca2+ release. The plasma membrane permeation pathways activated by the mitochondrial inhibitors are permeable to Mn2+. Store-operated Ca2+ channel (SOC) blockers (Ni2+, SKF96365 and Gd2+) and internal-store ATPase inhibitors (thapsigargin and bisphenol) antagonize Ca2+ influx induced by the mitochondrial inhibitors. The results indicate that the functional status of the sea urchin sperm mitochondrion regulates Ca2+ entry through SOCs. As neither CCCP nor dicycloexyl carbodiimide (DCCD), another mitochondrial ATPase inhibitor, eliminate the oligomycin induced increase in [Ca2+]i, apparently oligomycin also has an extra mitochondrial target

Occupational and Environmental Risks from Mancozeb in Aviation Facilities in the Banana Producing Area of Teapa, Tabasco, Mexico

Purpose: To identify occupational risks and practices in the four aerial fumigation facilities in the Sierra banana growing region and to evaluate environmental impacts from Mancozeb use.Methods: Occupational health risks were identified and practices in the four aerial fumigation facilities in the Sierra banana growing region were documented. Semi-structured interviews were conducted with installation managers. To evaluate environmental impact, samples of water and soil were collected and analysed in an acute toxicity bioassay with Vibrio fischeri, using uncontaminated soil and water to establish background levels.Results: Even in the largest and best-equipped facility, serious risks to workers’ health were encountered from inadequate use of protective equipment by workers. Furthermore, excessive use of pesticide, lack of re-use of unused product, poor facility design and poor use of wash-water were observed, resulting in  maximum toxicity of > 5 times background in discharged water. Parallel soil samples were > 20 times  more toxic than background, being most toxic at > 0.5 km from the discharge point.Conclusion: Areas of opportunity to improve worker health and the environment include proper and  consistent use of protective equipment, re-use of unused product, wastewater reduction and appropriate wastewater treatment.Keywords: Black Sigatoka, Ethylene thiourea, Fumigation, Pesticide, Mancozeb, Airports, Microtox, Vibrio fischeri, Occupational health risks, Toxicit

Evaluation of code formulations for NSM CFRP bond strength of RC elements

This paper presents an analytical analysis which intends to verify the accuracy of existing code formulations for predicting the pullout strength of NSM CFRP systems applied to concrete. A database with a limited set of parameters was gathered and two code formulations were tested on it. Then, a new approach was tested. This uses Data Mining algorithms to develop models to predict the pullout strength based on user chosen parameters. The results reveal that existent code formulations aren’t as accurate as expected and that Data Mining can be a sound alternative or, at least, a good complement since it can also help know and understand the key parameters with relevant influence on the pullout strength of such strengthening systems

Growth hormone (GH)‐induced reconstitution of CD8+ CD28+ T lymphocytes in a rare case of severe lymphopenia associated with Juvenile Haemochromatosis and Turner's syndrome.

Clin Endocrinol (Oxf). 2004 Oct;61(4):437-40. Growth hormone (GH)-induced reconstitution of CD8+ CD28+ T lymphocytes in a rare case of severe lymphopenia associated with Juvenile Haemochromatosis and Turner's syndrome. Porto G, Cruz E, Miranda HP, Porto B, Vasconcelos JC, Lacerda R, Roetto A, Daraio F, Bacelar C. Santo António General Hospital, Porto, Portugal. [email protected] Abstract This paper describes a rare case of Turner's syndrome associated with Juvenile Haemochromatosis and severe lymphopenia, followed-up for a period of 5 years. Because of the indication for treatment with growth hormone (GH), this case was observed as a model to analyse the effects of GH on growth, iron mobilization and lymphocyte reconstitution. For this purpose, a serial study of the T lymphocyte subpopulations CD4+, CD8+, CD8+ CD28+ and CD8+ CD28- was performed by immunophenotyping during the follow-up period. Besides the impact of both phlebotomy treatment and GH on the rapid growth and mobilization of 20.8 g of iron in 136 weeks, the most relevant observation was the finding of a significant expansion of CD8+ T lymphocytes expressing the costimulatory marker CD28 in the setting of the severe lymphopenia. These findings constitute new clinical evidence supporting the notion that the GH/IGF-1 system has an important role on the maintenance of T cell homeostasis in vivo, and that GH may be regarded as a putative therapeutic agent in T lymphocyte reconstitution. PMID: 15473875 [PubMed - indexed for MEDLINE

Development of Neurogenic Detrusor Overactivity after Thoracic Spinal Cord Injury Is Accompanied by Time-Dependent Changes in Lumbosacral Expression of Axonal Growth Regulators

Thoracic spinal cord injury (SCI) results in urinary dysfunction, which majorly affects the quality of life of SCI patients. Abnormal sprouting of lumbosacral bladder afferents plays a crucial role in this condition. Underlying mechanisms may include changes in expression of regulators of axonal growth, including chondroitin sulphate proteoglycans (CSPGs), myelin-associated inhibitors (MAIs) and repulsive guidance molecules, known to be upregulated at the injury site post SCI. Here, we confirmed lumbosacral upregulation of the growth-associated protein GAP43 in SCI animals with bladder dysfunction, indicating the occurrence of axonal sprouting. Neurocan and Phosphacan (CSPGs), as well as Nogo-A (MAI), at the same spinal segments were upregulated 7 days post injury (dpi) but returned to baseline values 28 dpi. In turn, qPCR analysis of the mRNA levels for receptors of those repulsive molecules in dorsal root ganglia (DRG) neurons showed a time-dependent decrease in receptor expression. In vitro assays with DRG neurons from SCI rats demonstrated that exposure to high levels of NGF downregulated the expression of some, but not all, receptors for those regulators of axonal growth. The present results, therefore, show significant molecular changes at the lumbosacral cord and DRGs after thoracic lesion, likely critically involved in neuroplastic events leading to urinary impairment