What Does It Mean for a Case to be 'Local'?: the Importance of Local Relevance and Resonance for Bioethics Education in the Asia-Pacific Region.

Contemporary bioethics education has been developed predominately within Euro-American contexts, and now, other global regions are increasingly joining the field, leading to a richer global understanding. Nevertheless, many standard bioethics curriculum materials retain a narrow geographic focus. The purpose of this article is to use local cases from the Asia-Pacific region as examples for exploring questions such as 'what makes a case or example truly local, and why?', 'what topics have we found to be best explained through local cases or examples?', and 'how does one identify a relevant local case?' Furthermore, we consider the global application of local cases to help extend the possible scope of the discussion, opening new avenues for the development of practical bioethics educational materials. We begin with a background description and discussion of why local cases enhance bioethics education, move to an overview of what is currently available and what is not for the region, and then outline a discussion of what it means to be local using example cases drawn from Hong Kong, Australia, Pakistan, and Malaysia. We are not creating a casebook but rather constructing by example a toolbox for designing active and dynamic learning cases using regional diversity as contextualised cases with generalised principles.

Age-related changes in adrenomedullin expression and hypoxia-inducible factor-1 activity in the rat lung and their responses to hypoxia.

Male rats aged 3 months, 12 months and 20 months were subjected to breathing 8% oxygen for 6 hours. Lung preproadrenomedullin (AM) messenger RNA (mRNA) levels were measured by solution hybridization-RNase protection assay while AM was measured by radioimmunoassay. The binding of hypoxia-inducible factor-1alpha (HIF-1alpha) to DNA was determined by electrophoretic mobility shift. There was an age-related increase in basal levels of preproAM mRNA and AM and of the binding of hypoxia-inducible factor (HIF) to DNA. Upon hypoxic stimulation, HIF binding to DNA increased in the young and middle-aged rats, but not in the old rats. AM gene expression increased in response to hypoxia in rats of all ages, but the increase was much less in the old rats. AM peptide levels in the lung decreased with age in hypoxia. In a separate experiment, male rats aged 3 months and 20 months were subjected to hypoxia as described above. PreproAM, calcitonin receptor-like receptor (CRLR), receptor activity modifying protein (RAMP) mRNA, HIF-1 and peptidyl-glycine-amidating monooxygenase (PAM) mRNA levels were measured by reverse transcription-polymerase chain reaction. All except PAM showed a decrease in basal levels and a diminished response to hypoxia in the old rats. Polysome profiling demonstrated decreases in the percentages of translatable preproAM mRNA in response to hypoxia, with a greater decrease in the old than the young rats. It is concluded that an age-dependent decrease in the hypoxic response of the AM system in the lung was associated with high basal levels of HIF activity and AM expression in the old rats, and a lower proportion of translatable preproAM mRNA in the old rats in response to hypoxia. Thus, the HIF-AM pathway may be impaired in the aged lung, and other mechanisms may be present to maintain an AM response to hypoxia.

Adrenomedullin and its receptor components in adipose tissues: Differences between white and brown fats and the effects of adrenergic stimulation.

Male Sprague-Dawley rats were subcutaneously injected with 2.5mg/kg phenylephrine or 2.5mg/kg isoproterenol or both (2.5mg/kg for each drug) for 4 days, twice a day. Samples of scapular brown adipose tissue (BAT) and epididymal white adipose tissue (WAT) were collected for the measurement of adrenomedullin (AM) levels and the gene expression of preproAM, calcitonin receptor like receptor (CRLR) and its activity modifying proteins (RAMPs) by radioimmunoassay and RT-PCR. These values were compared with those in the rats that received 0.9% saline. The gene expression of AM and AM receptor components in BAT are much less than that in epididymal WAT. In BAT there were an increase in AM peptide level after a combined treatment of alpha(1) and beta adrenoceptor agonists and increases in preproAM mRNA levels for rats treated with alpha(1) and beta receptor agonists alone or in combination. Both CRLR and RAMP2 mRNA levels of alphabeta group were increased significantly. In WAT, AM peptide level, RAMP1 and RAMP2 mRNA expression levels were augmented in the alpha group while CRLR mRNA level was enhanced in the beta group. The levels of AM, its receptor and RAMPs are much less in BAT than in WAT but adrenergic stimulation has a greater effect on the AM and its receptor components in BAT than those in WAT. AM stimulates lipolysis and increases the level of uncoupling protein-1 (UCP-1) in BAT. It may therefore enhance thermogenesis by increasing the availability of free fatty acids substrate as well as the UCP-1 level on the mitochondrial membrane.

Differential regulation of adrenomedullin gene expression in the fundic and pyloric regions of the rat stomach during acute and chronic starvation.

Adrenomedullin (AM) has been shown to be present in the stomach but the role of gastric AM is obscure. To investigate the effects of starvation on AM in the stomach, we studied the changes in gene expression of preproadrenomedullin (preproAM) and AM receptors by reverse transcription-polymerase chain reaction (RT-PCR), and tissue AM concentrations by radioimmunoassay (RIA) in the fundus and pylorus of the stomach of rats subjected to either acute (1-day) or chronic (4-day) starvation. An up-regulation of preproAM gene expression was observed in the fundus after acute starvation, and in the pylorus after chronic starvation. Immunoreactive AM (ir-AM) levels were increased in both fundus and pylorus after chronic starvation. In addition, marked reductions in the gene expression of fundic calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein (RAMP) 3 as well as the pyloric CRLR and RAMP2 were observed in the chronically starved rats. The present study suggests that the gene expression of preproadrenomedullin mRNA is differentially regulated by starvation in the different parts of the stomach.

Adrenomedullin gene expression and levels in the cardiovascular system after treatment with lipopolysaccharide.

To study the effect of septicaemia, the temporal changes in tissue adrenomedullin (AM) and preproAM mRNA levels were studied in the heart and blood vessels after lipopolysaccharide (LPS) injection. Radioimmunoassay and solution hybridization-RNase protection assays were used to follow the changes in AM and its mRNA levels respectively after intraperitoneal injection of 10 mg/kg LPS in rats. The preproAM mRNA levels increased at 1 h in the right atrium after LPS injection, while the AM contents decreased at 1 h in the left atrium. The preproAM mRNA levels increased at 3 and 6 h in the left ventricle, whereas it increased at 6 h in the right ventricles after LPS injection. There was an increase in preproAM mRNA levels at 1 and 3 h in the mesenteric artery, while AM levels were increased at 1, 3 and 6 h. However, there were no such changes in the thoracic aorta. There were also increases in tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta and IL-6 in the heart, and in the mesenteric artery (TNF-alpha and IL-1beta) and in thoracic aorta (IL-1beta and IL-6). The present results suggest that the biosynthesis and secretion of AM may be increased in cardiovascular tissues of rats injected with LPS, and that AM may play multiple roles in inflammation.

Increase in adrenomedullin gene expression in the left atrium and ventricle in the two-kidney one-clip renovascular hypertensive rats.

The 2-kidney 1-clip rat model was set up by clipping the left renal artery. At 5 weeks after clipping, there was an increase in preproadrenomedullin mRNA levels in both the left atria and the left ventricle. Adrenomedullin (AM) contents, however, increased in the left ventricle but decreased in the left atrium. These changes were not observed at 2 weeks after clipping. There were no changes in AM or preproadrenomedullin mRNA levels in the thoracic aorta and the mesenteric artery, and in plasma AM levels at 2 weeks or 5 weeks after clipping. We concluded that there was an increase in the secretion of AM in the left ventricle and the left atria in the 5 week renovascular hypertensive rat. The lack of change in plasma AM level suggests a paracrine function for the peptide in this setting.

Differential induction of adrenomedullin, interleukins and tumour necrosis factor-alpha by lipopolysaccharide in rat tissues in vivo.

The aim of the present study was to determine the temporal changes in tissue adrenomedullin (AM) and cytokine contents and cytokine and preproAM mRNA levels in the kidney, liver, adrenal gland and spleen of lipopolysaccharide (LPS)-treated rats. Rats were injected with LPS (10 mg/kg, i.p.). Radioimmunoassay and solution hybridization-RNase protection assays were used to follow the changes in AM and its mRNA levels, respectively; ELISA and reverse transcription-polymerase chain reaction were used to follow the changes in cytokines and their mRNA levels, respectively. In the kidney, the preproAM mRNA levels were increased 1 and 3 h after LPS treatment, whereas AM levels were decreased at 3 h. Interleukin (IL)-6 and IL-1beta levels were increased at 3 and 6 h, respectively. The preproAM mRNA levels were elevated in the liver 3 h after LPS injection. Concentrations of tumour necrosis factor (TNF)-alpha and IL-1beta were increased at l and 6 h, respectively. There were no changes in the levels of either preproAM mRNA or AM in the adrenal gland and the spleen. In the spleen, TNF-alpha levels were elevated at 1 and 3 h after LPS injection and IL-1beta was elevated at 1 and 6 h after LPS injection, whereas in the adrenal gland IL-1beta was elevated at 6 h after injection. The mRNA levels of the three cytokines were elevated at all three time intervals examined in the kidney, liver, adrenal gland and spleen, with the exception that TNF-alpha mRNA was not elevated in the adrenal gland at 6 h after LPS injection and IL-1beta mRNA was not elevated in the spleen at 3 and 6 h. The plasma concentrations of TNF-alpha were increased at 1 and 3 h after LPS injection, whereas plasma concentration of IL-1beta and IL-6 were elevated at 3 and 6 h for both. The present results suggest that the biosynthesis and secretion of AM may be differentially regulated in various tissues of rats injected with LPS and that AM may interact with cytokines during inflammation.

The inhibitory effect of adrenomedullin in the rat ileum: cross-talk with beta3-adrenoceptor in the serotonin-induced muscle contraction.

In contrast to vascular muscles, the contribution of a hypotensive peptide adrenomedullin (AM) to the regulation of visceral smooth muscles is obscure. The content, synthesis, and effects of AM on the muscular tone in rat ileum were explored. It was found that there was immunoreactive AM (301 pg/mg of protein) and AM mRNA expression (162 fg/pg actin mRNA) in the ileum and that AM evoked relaxation in ileal strips (Ki = 0.85 nM) precontracted with serotonin. Antagonists of both AM (AM(22-52)) and calcitonin gene-related peptide (CGRP(8-37)) receptors did not affect this AM-induced relaxation, whereas it was suppressed by a selective blocker of beta3-adrenoreceptor (SR 59230A). The AM-induced relaxation was accompanied by a production of cAMP. Antagonists of protein kinases A (KT 5720 and H-7) and an inhibitor of the ATP-dependent K(+)-channels (glibenclamide) attenuated the effect of AM. We suggest that AM is a local regulator of the ileal tone, with an inhibitory action on muscle contraction. AM may activate the beta3-adrenoceptors, resulting in protein kinase A activation, which in turn opens the ATP-dependent K(+)-channels.

Co-expression of adrenomedullin and adrenomedullin receptors in rat epididymis: distinct physiological actions on anion transport.

Adrenomedullin (AM) has been found in the brain as well as in various peripheral tissues, including reproductive organs such as the testis and the prostate. Here, we report the expression of AM in the rat epididymis and its role in anion secretion. Whole-epididymal extracts had 35.3 +/- 1.4 fmol of immunoreactive AM per mg of protein, and immunocytochemical studies showed positive AM immunostaining in the epithelial cells. By solution-hybridization-RNase protection assay, preproAM mRNA was detected at high levels in the epididymis. Gel filtration chromatography of AM showed two peaks, with the predominant one eluting at the position of authentic rat AM (1-50). Specific binding of AM to the epididymis, which could be displaced by calcitonin gene-related peptide, was observed. The epididymis also bound to calcitonin gene-related peptide, and this was displaceable by AM. Furthermore, the epididymis was shown to co-express mRNA encoding the calcitonin receptor-like receptor and receptor activity-modifying proteins, RAMP1/RAMP2. The corpus region had the highest AM level and gene expression and the lowest active peptide:precursor ratio. However, mRNA levels of the receptor and the receptor activity-modifying proteins were similar in all regions. In monolayer cultures derived from the rat epididymal cells, AM stimulated short-circuit current on the luminal side in a dose-dependent manner. Our results demonstrate the presence of AM, preproAM mRNA, AM receptors, and specific-binding sites in the rat epididymis as well as the possible role of AM in the regulation of electrolyte and fluid secretion in the epididymis.