Simultaneous measurement of gastric emptying of a soup test meal using MRI and gamma scintigraphy

Measurement of gastric emptying is of clinical value for a range of conditions. Gamma scintigraphy (GS) has an established role, but the use of magnetic resonance imaging (MRI) has recently increased. Previous comparison studies between MRI and GS showed good correlation, but were performed on separate study days. In this study, the modalities were alternated rapidly allowing direct comparison with no intra-individual variability confounds. Twelve healthy participants consumed 400 g of Technetium-99m (99mTc)-labelled soup test meal (204 kcal) and were imaged at intervals for 150 min, alternating between MRI and GS. The time to empty half of the stomach contents (T1/2) and retention rate (RR) were calculated and data correlated. The average T1/2 was similar for MRI (44 ± 6 min) and GS (35 ± 4 min) with a moderate but significant difference between the two modalities (p ≤0.004). The individual T1/2 values were measured, and MRI and GS showed a good positive correlation (r = 0.95, p ≤ 0.0001), as well as all the RRs at each time point up to 120 min. Gastric emptying was measured for the first time by MRI and GS on the same day. This may help with translating the use of this simple meal, known to elicit reliable, physiological, and pathological gastrointestinal motor, peptide, and appetite response

Startle-Freeze Behavior in Weaned Pigs

Pigs may express a startle response and then freeze after they have heard an auditory stimulus. The objective of this study was to induce startle-freeze behaviour, describe it and to seek potential variables that might influence it. A startle-freeze response lasting 1 to 12 seconds was produced in 36 pigs 5-6 weeks old penned in 12 groups (3 pigs per group), using a cymbal (26 cm radius) to produce a sound of 1 10 dB intensity. This was repeated at 4 minute intervals for 8 stimuli over 28 minutes. The duration of the startle-freeze response decreased over presentations and all pigs had ceased to respond by the seventh stimulus. The frequencies of social interaction, ingestion and lying or sitting behaviours before freezing decreased after the freeze period, and standing or walking increased. The behaviours shown before and after immobilisation were not independent (x\ = 101.9, p < 0.001). The social status of each group was determined from videotape records. The dominance rank of the pig was significantly related to the onset of immobilization; the most dominant pigs responded to the noise first, often 1 to 2 seconds ahead of lower ranked pigs (x\ = 15.74, p < 0.05). In conclusion, pigs show a clear startle-freeze response to a novel auditory stimulus, they habituate rapidly and the onset of startle-freeze behaviour depends upon their social status

Startle-Freeze Behavior in Weaned Pigs

Pigs may express a startle response and then freeze after they have heard an auditory stimulus. The objective of this study was to induce startle-freeze behaviour, describe it and to seek potential variables that might influence it. A startle-freeze response lasting 1 to 12 seconds was produced in 36 pigs 5-6 weeks old penned in 12 groups (3 pigs per group), using a cymbal (26 cm radius) to produce a sound of 1 10 dB intensity. This was repeated at 4 minute intervals for 8 stimuli over 28 minutes. The duration of the startle-freeze response decreased over presentations and all pigs had ceased to respond by the seventh stimulus. The frequencies of social interaction, ingestion and lying or sitting behaviours before freezing decreased after the freeze period, and standing or walking increased. The behaviours shown before and after immobilisation were not independent (x\ = 101.9, p < 0.001). The social status of each group was determined from videotape records. The dominance rank of the pig was significantly related to the onset of immobilization; the most dominant pigs responded to the noise first, often 1 to 2 seconds ahead of lower ranked pigs (x\ = 15.74, p < 0.05). In conclusion, pigs show a clear startle-freeze response to a novel auditory stimulus, they habituate rapidly and the onset of startle-freeze behaviour depends upon their social status

Collagen biosynthesis in cultured rat testicular Sertoli and peritubular myoid cells

The incorporation of 3H-proline into protein was regarded as a measure of total protein synthesis and the incorporation into hydroxyproline as indicative of collagen synthesis. Relative collagen synthesis (expressed as percent of total protein synthesized) by Sertoli and peritubular myoid cells cultured from 20-22 day old rat testis was estimated. In both secreted and cellular pools, relative collagen synthesis by Sertoli cells was significantly greater than by peritubular myoid cells. Coculture of Sertoli and myoid cells resulted in a significant increase in relative collagen synthesis when compared to monocultures of each cell type. Addition of serum to peritubular myoid cells resulted in a stronger stimulation of relative collagen production. Sertoli cell extracellular matrix inhibited relative collagen synthesis by peritubular myoid cells in the presence or absence of serum. Radioactivity into hydroxyproline as corrected per cellular DNA also showed similar results. Immunolocalization studies confirmed that both cell types synthesize type I and type IV collagens. These results indicate that stimulation of collagen synthesis observed in Sertoli-myoid cell cocultures is due to humoral interactions, rather than extracellular matrix, and Sertoli cell extracellular matrix regulates serum-induced increase in collagen synthesis by peritubular myoid cells

Survival of porcine delipated oocytes and embryos after cryopreservation by freezing or vitrification

The present study examined whether delipated porcine oocytes and embryos at various stages of development can be cryopreserved by conventional slow cooling or vitrification. Most (93%) of the 27 delipated morulae developed to blastocysts after freezing with 1.5 M propanediol + 0.1 M sucrose. Late morulae and early blastocysts delipated at 2-4 cell stage and cultured in vitro survived freezing either with 1.5 M glycerol + 0.25 M sucrose (10/18, 56%) or 1.8 M ethylene glycol + 0.25 M sucrose (14/19, 74%). Delipated 2-4 cell stage embryos and oocytes could be cryopreserved by vitrification with 40% ethylene glycol, 1 M sucrose and 20% fetal calf serum. Half (7/14) of the vitrified, delipated embryos developed to blastocysts after thawing. Of 48 delipated oocytes, 27 (56%) maintained an intact outline of the ooplasm after vitrification and underwent subzonal sperm injection. Fertilization was confirmed in 12 (25%) of these oocytes and 3 (6%) developed to morula stage. This study also aimed at developing a non-invasive method for cryopreserving porcine embryos after reducing their cytoplasmic lipid content without micromanipulation. Morulae and early blastocysts were centrifuged in the presence of cytochalasin B and cryoprotectants and then frozen immediately. More than half (14/24, 58%) of the centrifuged morulae developed to blastocycts after freezing with 1.5 M propanediol + 0.1 M sucrose. Greater than 70% of centrifuged early blastocysts survived freezing either with 1.5 M propanediol (30/31, 97%), 1.5 M glycerol (22/29, 76%) or 1.8 M ethylene glycol (21/29, 72%). These results demonstrated that delipation (lipid removal) from porcine oocytes and embryos at various stages enables their cryopreservation. A new insight into the development of a non-invasive method for cryopreserving porcine embryos was also provided