Rangeland dynamics of southern Ethiopia: (2). Assessment of woody vegetation structure in relation to land use and distance from water in semi-arid Borana rangelands.

The structure and advancement of woody vegetation was studied in a semi-arid rangeland of southern Ethiopia under three land-use systems (communal land, a government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. A total of 54 woody plant species were identified. Based on the subjective opinions of the pastoralists, 85% of the identified woody plants have forage values to livestock. Cadaba farinsoa, Ormocarpum trichocarpum, Rhus natalensis, Acacia brevispica, Cordia gharaf and Hibiscus sparseaculeatus were reported to have fair to good palatability. Tree equivalent (TE) density of all woody plants combined was greater (P <0.01) in the government ranch (1) 188 TE ha(-1)) and the communal land (1083 TE ha(-1)) than in the traditional grazing reserve (419 TE ha(-1)), whereas this did not vary significantly (P >0.05) along the distance gradient from water. The most important encroaching woody plant species in the study areas were in descending order: Commiphora africana, Acacia drepanolobium, A. brevispica, Acacia. tortilis, Grewia tembensis and Lannea floccosa. The density of individual encroaching woody plant species along the distance gradient from water was not consistent. All encroaching woody species had the highest TE density in the communal land. The prevalence of these species followed the pattern of intensity of use within the communal grazing area. Most of the woody species had the highest abundance in the height class >0-2m regardless of land use and distance gradient from water. This study investigated the advance of severe woody encroachment in the communal and government sites as well as along the distance gradient from water. Some of the important contributing factors that can be suggested are heavy grazing pressure (in both the communal and government sites), expansion of cultivation and reduced mobility of livestock due to settlement of the pastoralists in the communal land.

Rangeland dynamics in southern Ethiopia: (1) botanical composition of grasses and soil characteristics in relation to land-use and distance from water in semi-arid Borana rangelands.

The distribution and compositional pattern of the grass layer, as well as soil quality of southern Ethiopian semi-arid rangelands were examined under three land-use systems (communal land, government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. In total, 49 grass species were identified, 65% of which were perennials. Of the most commonly distributed highly desirable species, Chrysopogon aucheri showed the greatest frequency under the traditional grazing reserve (27.6%), and the lowest in the communal land (14.0%). The frequency of Cenchrus ciliaris was similar in all the study sites. The proportion of Lepthotrium senegalensis was low under the land-use systems (3.9%) and increased away from water sources (2.3%). Of the less desirable species, Sporobulus nervosus was extremely more abundant (<0.05) in the communal land (13.3%) than the traditional grazing reserve (3.3%) and the government ranch (1.9%). Sporobolus pyramidalis was dominant in the study sites, with similar (P>0.05) frequency percentages under the land-use systems and along the distance gradients from water. Basal cover was low and similar on all the study sites (3.3%). Concerning the soil texture, sand (71.1%) constituted the largest proportion, followed by silt (21.3%) and lastly, clay (7.7%). With regard to soil exchangeable cations, organic C and total nitrogen were generally low and did not show marked variation in all the study sites. The study showed significant differences for most of the vegetation variables between the communal land and the other land-uses. This suggested that grazing intensity was higher in the communal land and moderate in the government ranch and in the traditional grazing reserves (kallos). The lack of significant differences in most of the studied (vegetation) variables along the distance gradient from water could be ascribed to the fact that grazing disturbance has already exceeded a certain threshold of degradation. Under the present low states of soil nutrients and rainfall, cultivation is neither sustainable nor environmentally friendly and this will lead to further degradation of the soil in these marginal lands.

Rangeland dynamics in southern Ethiopia: (3). Assessment of rangeland condition in relation to land-use and distance from water in semi-arid Borana rangelands.

The condition of the semi-arid Borana rangeland in southern Ethiopia was assessed by studying different land-use systems (communal land, a government ranch and a traditional grazing reserve enclosure) and along a distance gradient (near, middle and far) from water sources. The assessment incorporated the soil, herbaceous and woody plant layers. Two methods were employed to evaluate the grass layer, viz. ecological condition index (ECI) and weighted palatability composition (WPC). The ECI on the government ranch was 21.7% and 26% greater than that of the traditional reserve and the communal land, respectively. The WPC on the government ranch was 83.3% and 48.6% greater than that of the communal area and the traditional reserve, respectively. Both ECI and WPC values were similar for all distance sites from water. Tree equivalent (TE) density, of all encroaching woody plants combined, was higher on the communal land (504 TE ha(-1)) than the government ranch (373 TE ha(-)1) and traditional grazing reserve (118 TE ha(-1)), but with no marked variations in the distance sites from water. Height class distribution of encroaching woody plants in the study areas showed the largest abundance (range: >50-100%) at the height class >0-2m. Tree equivalents per hectare of encroaching woody plants were negatively correlated (r = -0.60) with ECI and WPC and positively correlated (r=0.87) with percentage bare ground. The correlation (r = 0.50) between percentage bare ground and soil compaction was positive and low. Although the government ranch had a greater composition of highly palatable grass species than the other land uses, the rangeland was not in good condition due to severe bush encroachment. The communal land was generally in poor condition. In the traditional grazing reserve, bush encroachment was not a problem, but the productivity of the grass layer was poor when assessed on the basis of ecological and palatability merits. The negative interaction of TE density of all encroaching woody plants combined with ECI or WPC and the positive interaction with bare ground, may suggest that the abundance of these species is more critical in aggravating deterioration in grassland productivity. Therefore, the priority of any bush control program must be towards minimizing the abundance of these woody plants.

Rapid initial gastric emptying and hypersensitivity to gastric filling in functional dyspepsia: effects of duodenal lipids.

OBJECTIVE: Impaired distension-induced gastric accommodation and hypersensitivity to distension have been demonstrated by gastric barostat in patients with functional dyspepsia (FD). In this study we investigated distension-induced responses to gastric filling with water in healthy volunteers and FD patients, using non-invasive ultrasonography. MATERIAL AND METHODS: Eighteen healthy volunteers and 18 FD patients were given infusions of 10 ml saline or lipid (3 kcal/ml) through a nasoduodenal tube. After tube retraction, the stomach was filled with 1000 ml water during 10 min. Intragastric volume was monitored by 3D ultrasonography, and fullness, pain and nausea were assessed. RESULTS: Compared with healthy volunteers, patients with FD had faster gastric emptying at 5 min (p = 0.0008) and reported more fullness (p = 0.006) during gastric filling with water. Prior duodenal lipid exposure reduced initial gastric emptying rate in FD patients to the level seen in healthy volunteers. However, despite similar gastric volumes, the patients still reported greater fullness (p = 0.002) and nausea (p = 0.01). CONCLUSIONS: Patients with FD had abnormally rapid initial gastric emptying of water and hypersensitivity to gastric filling. Though normalizing gastric emptying rate and volumes, duodenal lipid exposure did not improve hypersensitivity. Rapid initial gastric emptying of water might be a sign of impaired distension-induced gastric accommodation.

Pressure-induced gastric accommodation studied with a new distension paradigm. Abnormally low accommodation rate in patients with functional dyspepsia.

OBJECTIVE: A new distension paradigm, by which the gastric volume response to ramp-tonic distension can be analysed in detail, has been developed. The aim of this study was to investigate the applicability of this new paradigm in man, and to compare pressure-induced gastric accommodation in healthy volunteers (HV) and patients with functional dyspepsia (FD). MATERIAL AND METHODS: Ten HV, and 11 FD patients were examined twice; once in the fasting state and once postprandially. Intragastric bag pressure was raised from 1 to 12 mmHg in 4 min (ramp phase) and then kept constant for 5 min (tonic phase). RESULTS: Compared to HV, fasting FD patients had lower gastric accommodation rates (0.9+/-0.2 versus 2.5+/-0.4 ml/s, p=0.002), lower maximum volume (239+/-39 versus 428+/-64 ml, p=0.01) and a longer accommodation time (157+/-26 versus 92+/-15 s, p=0.03). A test meal prior to distension tended to normalize the response in FD patients. CONCLUSIONS: This new barostat paradigm allowed detailed analysis of short-term pressure-induced accommodation in man. Impaired gastric distension-induced accommodation is a novel abnormality in FD.

Octreotide in patients with active ulcerative colitis treated with high dose corticosteroids (OPUS 1).

BACKGROUND: In ulcerative colitis the intestinal somatostatin content is reduced. Somatostatin has several immune-inhibitory effects. In vitro it diminishes activity of intestinal lymphocytes and peripheral blood monocytes. Its long-acting analogue octreotide has beneficial effects on mucosal damage in acute experimental acetic acid colitis in rats. AIMS: To determine the potential benefits of octreotide as a treatment for patients with severe ulcerative colitis treated with high dose corticosteroids. PATIENTS: Forty-two patients with severe ulcerative colitis (more than 10 points on the Powell-Tuck scoring system and mucosal disease Heatly grade III or IV). METHODS: In a multi-centre, double blind, placebo-controlled trial all patients were treated with oral 5-ASA (1.6-2.4 g daily) and high dose corticosteroids (tapering off from 60 to 80 mg daily). They were randomly assigned to receive subcutaneous placebo (n = 22) or octreotide 500 microg (n = 20) thrice daily during 21 days. Clinical and endoscopic disease activity, histology and laboratory parameters were obtained during the study period. RESULTS: Clinical disease activity for both octreotide and placebo were not significantly different at baseline and after 21 days of treatment. Endoscopic disease activities (mean +/- SD) changed from 12.5 +/- 4.7 to 7.2 +/- 5.3 for octreotide, and from 11.5 +/- 5.0 to 5.0 +/- 3.4 for placebo (NS). Seven patients from both groups received additional treatment (colectomy (n = 6), cyclosporin (n = 1)). Adverse events occurred equally in both groups. CONCLUSIONS: Subcutaneous administration of octreotide 500 microg thrice daily is not of additional benefit as adjuvant therapy to high dose corticosteroids in severe ulcerative colitis.