Influence of obestatin on the histological development of the small intestine in piglets during the first week of postnatal life.

Obestatin is a gastrointestinal peptide having wide-ranging effects on cell proliferation; however, its mechanism of action remains poorly understood. Thus, the aim of the study was to elucidate the effect of exogenous obestatin on the postnatal structural development of the small intestine. Seven-day-old piglets with an average BW of 1.56 ± 0.23 kg were divided into four groups (n = 10) that received intragastrically obestatin (2, 10 or 15 µg/kg BW) or vehicle. After a 6-day experimental period, morphological analysis of gastrointestinal tract and small intestine wall (mitosis and apoptosis indexes, histomorphometry of mucosa and muscularis layers) was performed. The study revealed a seemingly incoherent pattern of the histological structure of the small intestine among the experimental groups, suggesting that the effect of obestatin is both intestinal segment specific and dose dependent. Histomorphometric analysis of the small intestine showed that higher doses of obestatin seem to promote the structural development of the duodenum while simultaneously hindering the maturation of more distal parts of the intestine. Intragastric administration of obestatin increased the crypt mitotic index in all segments of the small intestine with the strongest pro-mitotic activity following the administration of obestatin at a dose of 10 and 15 µg/kg BW. The significant differences in the number of apoptotic cells in the intestinal villi among the groups were observed only in proximal jejunum and ileum. In conclusion, it seems that obestatin shows a broad-spectrum of activity in the gastrointestinal tract of newborn piglets, being able to accelerate its structural development. However, the varied effect depending on the intestinal segment or the concentration of exogenous obestatin causes that further research is needed to clarify the exact mechanism of this phenomenon.

Bus dynamics for mobility-aid securement design.

Mobility-aid securement on large urban transit buses has been designed without an adequate knowledge of either the accelerations that are likely to occur in normal operations or the maximum accelerations that are possible short of an impact accident. These normal operation accelerations are important because they are the source of motion and corresponding sense of insecurity on the part of the passenger when riding in a mobility-aid on a bus. This paper describes the equipment and procedures used to measure the distribution of accelerations to be expected on large buses in normal transit service and the maximum accelerations possible during extreme maneuvering for six different sizes and types of transit buses. Included in the tests were low-floor buses of different lengths, a high-floor bus, a 40-ft (12.2-m) low-floor double-decker bus, and a 60-ft (18.3-m) low-floor articulated bus. During in-service tests, the accelerations were generally a function of the driver. In maneuvering tests, the mechanics of the bus design were the controlling factors. The results show that, in general, normal driving accelerations were typically less than 0.2 g in all directions and very rarely greater than 0.4 g. In the event of an emergency-driving situation, forward and turning accelerations may reach 0.4 g and stopping may result in 0.8 g.