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Biomedical subjects

N Christofides

Publications and source records attributed to N Christofides.

10 recordsLinked to original sources

The value of advocacy in promoting social change: implementing the new Domestic Violence Act in South Africa.

South Africa's first democratic government passed the Domestic Violence Act (DVA) into law in 1998 as part of local and international commitments to protecting the human rights of women. Although the Act was welcomed as groundbreaking legislation, delays in implementing it led to increasing frustration. This paper describes an advocacy campaign conducted by the Soul City Institute for Health and Development Communication in partnership with the National Network on Violence against Women, to ensure the effective implementation of the DVA. Lessons from the campaign stress the importance of coalition building to draw on diverse strengths, and the use of a combination of advocacy tools, including lobbying, media advocacy and social mobilisation to achieve campaign goals. Given the critical role NGOs dealing with victims/survivors of domestic violence and the justice system played in lobbying for change and drafting the new law, their exclusion from the implementation process was ironic. While many advocacy efforts focus on the development of policy and legislation, ongoing efforts are needed to ensure effective implementation, the commitment of adequate resources and monitoring to identify gaps and propose new solutions. Our experience highlights the important role of policy advocates in connecting the multiple streams at play in the policy and legislative arena.

Communication↗

The new pariahs: discourse on the tobacco industry in the Sydney press, 1993-97.

OBJECTIVE: To review the principal sub-texts contained in all press coverage and references to the tobacco industry in a major Sydney newspaper over five years. METHOD AND SAMPLE: After excluding value-neutral financial page reports, thematic analysis of all value-laden references to the tobacco industry in the Sydney Morning Herald, January 1993 to December 1997. RESULTS: Some 155 articles containing 221 separate references to the tobacco industry were identified. Eight sub-texts (callous merchants of death; conspiracy/cover-up; blood money; toxic pied pipers; corporate leviathans; beleaguered/legitimate industry; index case of unethical or corrupt practice; and bumbling fools) accounted for all 221 references. Eighty-nine per cent of references to the industry framed it negatively. Journalists or regular newspaper columnists authored 56% of the references. Only 5% of comments were attributed to tobacco company sources. CONCLUSIONS: In press reports, the tobacco industry is routinely framed as a corporate pariah by journalists, the public, government spokespeople and tobacco control advocates. IMPLICATIONS: Routine negative publicity about the tobacco industry is likely to significantly reduce its public credibility and political influence.

Humans↗

Determination of free triiodothyronine by six different methods in patients with non-thyroidal illness and in patients treated with amiodarone.

We performed a methodological comparison of free triiodothyronine (FT3) estimates in patients with liver cirrhosis and renal failure. Patients were classified in terms of severity of illness on the basis of their total triiodothyronine, total thyroxine and reverse triiodothyronine profiles. FT3 levels, measured in direct dialysis, microchromatography, labelled analogue and two-step immunoextraction assays were significantly (P < 0.01) lower than the control group in all patient categories. However, FT3 measured by a labelled antibody radioimmunoassay was significantly reduced only in the most severely ill sub-group of patients. In a further group of patients on long-term amiodarone therapy for cardiac disease all FT3 methods, with the exception of the labelled antibody radioimmunoassay and an analogue method, yielded significantly (P < 0.01) reduced levels. A significant negative association between FT3 and subject age was demonstrated for all methods except the labelled antibody radioimmunoassay, and a weak but significant negative correlation between log thyrotropin and FT3 was only seen with this assay. Three methods demonstrated a correlation (P < 0.02) with albumin levels in patients with the 'low T3 syndrome'. In this group, albumin had a predictive value (P < or = 0.02) for four out of six assays as determined by stepwise variable selection. Our findings suggest that users of FT3 assays should exercise caution in interpreting results in non-thyroidal illness and amiodarone treated patients, as there are method-related differences in the profiles obtained.

Adult↗

Atrial natriuretic peptide: an endogenous factor enhancing sodium excretion in man.

For many years experimental evidence has suggested the existence of a circulating factor able to enhance sodium excretion. Very recently peptides with natriuretic activity in experimental animals have been isolated from mammalian and human cardiac tissue. In order to determine whether this natriuretic activity has relevance to man we have studied the effects of an infusion of alpha-human atrial natriuretic peptide (alpha-h-ANP) in normal subjects. Sodium excretion trebled (P = less than 0.005) during the infusion of a calculated dose of 15 pmol of alpha-h-ANP min-1 kg-1 and there was an accompanying diuresis; radioimmunoassay of plasma alpha-h-ANP during the natriuresis indicated a mean peak incremental concentration of 203 +/- 78 (SEM) pmol/l. The infusion of a calculated dose of 1.5 pmol min-1 kg-1 did not affect sodium excretion. There were no haemodynamic changes and no side effects were noted.

Adult↗

Peptide-containing nerves in human urinary bladder.

Nerves containing immunoreactive vasoactive intestinal polypeptide (VIP), substance P and two newly discovered peptides, neuropeptide tyrosine (NPY) and PHI (peptide having N-terminal histidine and C-terminal isoleucine), have been found in the human urinary bladder by immunocytochemistry and radioimmunoassay. Somatostatin immunoreactivity was detected by radioimmunoassay. The VIP-immunoreactive nerves were widely distributed in all regions, but were particularly dense beneath the epithelium and in the muscle layer. Scattered intramural ganglia were found to be reactive to VIP antiserum. Higher concentrations of extractable VIP were detected in the trigone than in the dome. VIP- and PHI-immunoreactive nerves were similarly distributed, the latter being less numerous. NPY-immunoreactive nerves were seen mainly in the muscle layer, particularly in the trigonal area. The distribution patterns of VIP- and NPY-immunoreactive nerves resembled those of the previously reported cholinergic and adrenergic nerves, respectively. Many blood vessels were found to be innervated by both types of immunoreactive nerves. Scattered substance P-immunoreactive fibers were occasionally seen, being present in the submucosa and around the detrusor muscles. The significance of these nerves remains to be elucidated.

Fluorescent Antibody Technique↗

Pancreatic polypeptide is not involved in the regulation of the migrating motor complex in man.

The role of pancreatic polypeptide (PP) and motilin in the regulation of the migrating motor complex (MMC) was studied in normal subjects. Both plasma motilin and PP levels changed cyclically in the fasted state and were highest in the late phase II period preceding the activity front in the duodenum. A continental breakfast invariably disrupted the MMC and induced a fed pattern of motility. After the meal plasma motilin levels decreased whereas PP levels rose significantly. Infusion of pure porcine motilin during the fasted state induced an activity front and a rise in plasma PP levels. Infusion of bovine PP in doses producing plasma PP levels above the postprandial values neither induced an activity front nor prevented its occurrence. During PP infusion, however, plasma motilin levels were low, although the activity front was not inhibited. PP seems to have no clear role in the regulation of the motor component of the MMC of man. The role of motilin in the production of the activity front of the MMC is discussed.

Duodenum↗

Plasma motilin, gastrin, and enteroglucagon and feeding in the human newborn.

Plasma concentrations of motilin, gastrin, and enteroglucagon were measured in cord blood and during the first 24 days of life before feeding in 45 term and 63 preterm, healthy infants. Levels of these hormones rose steeply after birth, reaching concentrations that were much higher than those in fasting adults. These increases in hormone concentration were not present in a group of 10 preterm infants who had received only intravaenous dextrose from birth because of hyaline membrane disease. Our findings suggest that early enteral feeding may trigger the postnatal increase in plasma concentrations of gut hormones and that this could play an important role in the physiologaical adaptations to extrauterine nutrition.

Fetal Blood↗

Release of VIP, secretin and motilin after duodenal acidification in man.

Plasma VIP, secretin and motilin were measured in 9 volunteers following intraduodenal instillation of 50 ml of 0.1 mol/1 HCl over 3 minutes. VIP rose from 1.7 +/- 0.7 pmol/1 to a peak at 6 minutes of 6.6 +/- 0.9 pmol/1 and was still significantly elevated at 30 minutes. By comparison the elevation of secretin was more transitory rising from a basal value of 2.5 +/- 0.4 pmol/1 to a peak of 10 +/- 1.5 pmol/1 at 3 minutes and returning to baseline by 10 minutes. The rise of motilin, from a higher baseline, was intermediate in pattern, from 23 +/- 7 pmol/1 basally to a 4 minute peak of 40 +/- 10 pmol/1. Thus the elevation of VIP was the most longlasting, and while probably not of sufficient magnitude to stimulate pancreatic bicarbonate secretion via the circulation, could reflect a significant local role in regulating the response of the intestinal mucosa to acid.

Bicarbonates↗

Release of motilin in man.

The effects on motilin release of various stimuli including an ordinary hospital lunch and ingestion of equicaloric amounts of protein (steamed cod), fat (double cream), or carbohydrate (glucose solution), and intraduodenal instillation of acid (0.1M HCl) and alkali (0.3M tris buffer, pH 10.2) have been investigated in healthy volunteers. Duodenal acidification resulted in a 90% rise of plasma motilin while after intraduodenal instillation of alkali motilin fell. No significant change was seen after a normal hospital lunch and the protein meal, and a small fall was observed after glucose. By contrast, after ingestion of 60 g fat motilin showed a peak increase of 65% at 30 minutes and was still significantly elevated at 60 minutes. Exogenous motilin has been reported to delay gastric emptying and this is also seen after duodenal acidification and fat ingestion. We conclude that motilin may be released physiologically by these stimuli and mediate their effects on gastric emptying in man.

Adult↗