Biochemical characterization of various populations of isolated bovine adrenal chromaffin cells

Various populations of bovine adrenal chromaffin cells were isolated first by successive digestions with collagenase (original cell preparation) followed by sedimentation through a stepwise bovine serum albumin gradient (cell layers I, II and III). At the fine structural level, the ratios between the number of adrenaline-cells and noradrenaline-cells were 1.9 in the original cell preparation and 0.9, 2.0 and 4.6 in cell layers I, II and III, respectively. The catecholamine content of each cell population was also measured by spectrofluorometry. The original cell preparation contained 20.1 and 12.2 nmol per 10⁶ cells of adrenaline and noradrenaline, respectively. Each cell layer had similar total amount of catecholamines (from 38.3 to 40 nmol per 10⁶ cells) but their adrenaline/noradrenaline content ratios varied from 0.6 in cell layer 1 to 1.3 and 3.3 in cell layers II and III, respectively. Incubation of the cells in the presence of acetylcholine (50 μM) induced a release of catecholamines which was proportional to the cell content of each amine. However, the percentage of total cell content released was much higher in cell layer I (20%) than in cell layers II (8%) and III (5%). Finally, each cell population was also analyzed for its ability to respond to a muscarinic stimulation of cyclic GMP level and to bind [³H]etorphine, a highly potent opiate agonist. Acetylcholine induced 3.15-, 2.15- and 4.21-fold increases in the levels of cyclic GMP in the original cell preparation, cell layers II and III, respectively, but not in cell layer I. Conversely, the high affinity opiate binding site for [³H]etorphine was almost exclusively confined to cell layer III (B_max of 28.4 fmol per 10⁶ cells as compared with 2.8–7.5 fmol in the other cell preparations). These results indicate that bovine adrenal chromaffin cells can be separated according to their content in adrenaline and noradrenaline and their response to nicotinic, muscarinic and opiate stimuli.     

Osteogenesis imperfecta

Osteogenesis imperfecta (OI) is the most frequently occurring congenital disorder with an increased fracture rate and systemic skeletal involvement. The vast majority of patients have an autosomal dominant form of OI resulting from a mutation in one of the two type I collagen genes COL1A1 or COL1A2. Since 2006, eight genes for autosomal recessive forms of the disorder have been identified, as well as one additional gene for autosomal dominant OI. Our knowledge concerning molecular pathophysiology has been substantially broadened, such that the paradigm of OI as a pure ??collagenopathy?? no longer applies and the clinical classification system will have to be revised. Standard therapy for the more severe forms of OI comprises intravenous administration of bisphosphonates. Additional elements of a multimodal therapeutic concept include surgical intervention for bone deformities or fractures and physiotherapy.     

Health promotion priorities for general practice: constructing and using "indicative prevalences".

OBJECTIVE--To construct indicative prevalences for a range of diseases and risk markers and use them in planning health promotion interventions in primary health care. DESIGN--Indicative prevalences comprised point prevalence, incidence, and mortality measures. Use of data from Office of Population Censuses and Surveys, Northern Regional Health Authority, and Newcastle health and lifestyle survey 1991, and research papers to determine prevalence adjusted for age and sex in a hypothetical practice with a list of 10,000 patients. SETTING--Newcastle upon Tyne, England. RESULTS--Indicative prevalences were highest for common risk markers such as failure to achieve exercise targets (6871), moderate to extreme obesity (2785), and smoking (2689); moderate for overt disease such as angina (175) and stroke (20/year); and low for events such as suicide (1/year) and deaths from malignant melanoma (2/10 years). CONCLUSIONS--Given limited time and resources, brief interventions to reduce smoking and the systematic case finding and management of patients with hypertension, angina, and previous myocardial infarction are likely to be the highest priorities for health promotion in primary care.