Search

Although Mozambique's infertility prevalence is one of the highest in southern Africa, there are very few studies on the subject. Anthropological research carried out from September 2001 to February 2002 in the rural area of the Magude district revealed various cultural and behavioural patterns relevant to the problem of childlessness. These patterns are related to the sexual and marital norms of polygyny and to the system of patrilineality. Patrilineal descent, polygamy and massive male labour migration to South Africa have created a contradictory mix of situations involving women and their reproductive role in society. The pressure on women to become pregnant and give birth, combined with the prolonged absence of their migrant husbands, leads them into conditions of vulnerability, which impel them to seek partners outside the marriage in order to conceive. In this context, extra-conjugal relations constitute the main channel for STDs, which are a major cause of infertility. [ABSTRACT FROM AUTHOR]

Eight dogs, four with intact vagi and four with vagotomy, were studied to see if the gastric secretory effect of intravenously administered L-amino acids is mediated by a gastrointestinal (GI) hormone or hormones. Intravenous infusion of amino acids produced a significant secretory response in denervated and in innervated stomachs. When the known sites of formation of GI hormones were removed by resection of antrum, duodenum, pancreas, jejunum, ileum, and colon, the gastric stimulatory effect of amino acids was not changed significantly in denervated stomachs but was greatly increased in innervated stomachs. We conclude that amino acids have a direct effect on parietal cell secretion that is not dependent on the intermediary release of a stimulatory hormone, and that evisceration enhances this effect in dogs with intact vagi.

To determine if the secretory response to protein in the gut is due to direct effects of absorbed amino acids on the parietal cells, to hormonal effects, or to a combination of both, Heidenhain pouch secretion and plasma amino nitrogen levels were measured during enteral infusions of casein or liver extract, as well as during intravenous infusions of amino acids, in three dogs with and three dogs without portacaval transposition. In the dogs without portacaval transposition, gastric secretory responses were slight and did not differ significantly; secretory responses were seen only during infusions in which elevations of plasma amino nitrogen values occurred. In dogs with portacaval transposition, secretory responses to both casein and liver extract were significantly higher (P less than 0.02) than was the response to intravenous amino acids, while plasma amino nitrogen levels rose to virtually identical levels during all three kinds of infusion. These data support the hypothesis that absorbed amino acids contribute to the intestinal phase of gastric secretion. The finding that casein and liver extract in the gut evoked greater gastric secretion responses than did intravenous amino acids, even though increases in plasma amino nitrogen levels were similar, suggests that the intestinal phase results form the combined effects of absorbed amino acids and hormonal influences rather than from the effects of amino acids alone.

The effect of intravenous administration of a fat emulsion on canine gastric secretion stimulated by intravenous infusion of amino acids, pentagastrin or insulin was studied. The fat preparation was given at a rate of 30 ml/hour for 2 hours, and its effects were compared with those of a comparable amount of saline solution, each given on three separate occasions in each dog. Fat did not alter the Heidenhain pouch secretion stimulated by intravenous amino acids (1.10 versus 1.11 mmol of hydrogen ion, p greater than 0.9) or the gastrostomy secretion stimulated by intravenous insulin (9.22 versus 9.54 mmol of hydrogen ion, p greater than 0.7) but had a modest inhibitory effect on Heidenhain pouch secretion stimulated by pentagastrin (2.75 versus 3.54 mmol of hydrogen ion, p less than 0.05). These data provide indirect support for the contention that the inhibition of gastric secretion by fat in the gut is mediated by the release of an enterogastrone rather than by a direct effect of absorbed fat. Because gastric stimulation by intravenous fat was not observed in the dog, it seems likely that intravenous fat emulsion can be given to seriously ill patients without fear of an increased likelihood of peptic ulceration due to induced gastric hypersecretion.

The intestinal phase of gastric secretion has been thought to be due to the release of a hormone from the gut mucosa, and several properties have been attributed to this as-yet unidentified hormone. An amino acid solution, known to stimulate gastric secretion, was tested to see if it possesses several of these properties, i.e., inactivation by the liver, and the ability to augment the maximum responses to pentagastrin and histamine. In six dogs with Heidenhain pouches the gastric secretory responses to peripheral and portal intravenous administration of a solution of mixed L-amino acids were measured. The mean peak response of three such separate peripheral infusions in each dog was 370 microEq/30 minutes while the peak response to intraportal infusion was only 45 microEq/30 minutes (p < .05). In three dogs with Heidenhain pouches the intravenous administration of amino acids together with pentagastrin resulted in significant augmentation of the peak response to pentagastrin alone (p < .025). Similarly, administration of amino acids with histamine resulted in augmentation of the peak response to histamine alone (p < .05). Because amino acids mimic the actions of the "intestinal phase hormone" in these respects it is suggested that they may account, at least in part, for the intestinal phase of gastric secretion. In addition, amino acids absorbed during protein digestion may contribute to the gastric hypersecretion which is regularly seen with portosystemic shunts.