Chitinase 3-like 1 expression by human (MG63) osteoblasts in response to lysophosphatidic acid and 1,25-dihydroxyvitamin D3.

Chitinase 3-like 1, otherwise known as YKL-40, is a secreted glycoprotein purported to have a role in extracellular matrix metabolism. The first mammalian cell type found to express YKL-40 was the human osteosarcoma-derived osteoblast, MG63. In that first study the active vitamin D3 metabolite, 1,25-dihydroxycholecalciferol (1,25D), stimulated YKL-40 expression, thereby indicating that a vital factor for skeletal health promoted YKL-40 synthesis by bone forming cells. However, when these MG63 cells were exposed to 1,25D they were also exposed to serum, a rich source of the pleiotropic lipid mediator, lysophosphatidic acid (LPA). Given that 1,25D is now known to co-operate with selected growth factors, including LPA, to influence human osteoblast differentiation we hypothesised that 1,25D and LPA may work together to stimulate osteoblast YKL-40 expression. Herein we report that 1,25D and LPA synergistically promote YKL-40 expression by MG63 cells. Inhibitors targeting AP1, MEK, Sp1 and STAT3 blunted the expression of both alkaline phosphatase and YKL-40 by MG63 cells in response to co-stimulation with 1,25D and LPA. Other ligands of the vitamin D receptor also co-operated with LPA in driving YKL-40 mobilisation. Collectively our findings highlight another important role of 1,25D and LPA in the regulation of human osteoblast function.

Posttraumatic stress and co-morbidity following myocardial infarction among older patients: the role of coping.

This study aimed to investigate co-morbidity and coping strategies among older patients who suffer from different levels of posttraumatic stress disorder (PTSD) following myocardial infarction. Ninety-six older myocardial infarction (MI) patients were recruited from two general practices and completed the Posttraumatic Stress Diagnostic Scale (PDS), the General Health Questionnaire-28 (GHQ-28) and the COPE Scale. Ninety-two older patients with no previous MI experience constituted the control. Using the PDS, 30, 42 and 28% had full, partial and no-PTSD respectively. There were significant differences between the patient groups and the control on all GHQ-28 sub-scales. Significant differences were also identified between the patient groups in the following coping strategies: seeking emotional social support, suppression of competing activities, restraint coping, focusing on and venting of emotion, mental and behavioural disengagement. Controlling for bypass surgery, previous mental health difficulties, angioplasty, heart failure and angina, MANCOVA results did not change the overall results of the GHQ-28 but changed the results of coping in that seeking emotional social support and behavioural disengagement stopped being significant. Coping was a partial mediator between different levels of post-MI PTSD and co-morbidity. Depending on the severity of PTSD symptoms, co-morbidity and coping strategies can vary among older patients. Older patients with full-PTSD tend to use both maladaptive coping strategies as well as problem-focused coping.

Chemicals in the environment.

Synthetic chemicals are now being incorporated into the earth's ecosystems at a rate and in such manners as to alarm environmentalists. These chemicals are the uncontrolled waste products of a technological society. Most prominent among them at the present time are organochlorine, organomercurial and lead compounds. Persistent members of these groups disperse in water, air and animal tissues. Also they have the capacity for concentration in animal food chains, thereby reversing the historical expectation of the dilution and degradation of wastes. Examples of damage from environmental residues to man are at this stage speculative but documentation from effects on wild species is abundant. Already several species of birds seem on their way to extinction. These wild species constitute a gratuitous monitoring system which already has signaled clear warnings for the welfare of man.