Prenatal muscle development in the pig

The basis for the project was a comparison of the prenatal growth of the largest and smallest pigs within litters. The differential growth rate of these two groups provides a natural experiment for determining factors important in limiting growth. The investigation concentrated on muscle growth because of its agricultural importance, but gross measurements of the fetus and its membranes were also made in an attempt to ascertain the cause of the size difference.The material consisted of 12 gravid uteri of Large White x Landrace gilts sacrificed at approximately 10 days intervals from 38 days gestation until term, together with 2 new born litters. The project can be divided into 3 sections according to the techniques employed.1. Fetal and Placental growthGross measurements of fetal weight, length and position within the uterine horn were taken from each animal together with x-rays of the forelimbs of fetuses from two litters. The results showed that the small littermates, as well as being lighter, were shorter, had a lower ponderal index, had a less well ossified skeleton and tended to be found in the more crowded of the two uterine horns. All but the last characteristic is descriptive of small-for-dates babies in comparison to normal. Mean fetal weight was found to decline with increasing number in a uterine horn but the spacing between fetuses was always even. Examination of farm records (247 pigs) showed a small (80gm.) but significant difference in the birth weights of male and female pigs.The fresh weight, in situ length, circumference and area of all the fetal membranes were measured. All the above parameters were found to increase significantly during gestation except for placental length. This last parameter was found to show a strong position effect with the shortest placentae generally occurring in the middle region of the uterine horn. Macroscopic placental area was found to be an adequate measure of the exchange area as no difference could be demonstrated between placentae in terms of the surface enlargement due to their microscopic ridges. In general, fetal membrane weight and area correlated well with fetal weight, in contrast to placental length and circumference. The endometrium at the site of each fetus was thrown into macroscopic folds of up to 2 cm in height. These folds were found to be significantly greater in more crowded horns so that these placentae partly compensated for their shorter length.2. Muscle histology and histochemistryFrozen sections of the semitendinosus muscle stained with haemotoxylin and eosin were used to calculate fibre number and the mean sizes of primary and secondary fibres. Fibre number increased from 38 days until 85-90 days gestation when total fibre number was about 350,000. The time when fibre hyperplasia ceased was estimated from the time when total fibre number and the secondary/primary fibre ratio became constant. From 60 days onwards the larger littermate had more fibres in the m. semitendinosus than its smaller sibling and the difference at birth was 17%.Primary fibres were observed at 38 days and continued to form until 60 days. Equal numbers of primaries (about 18,000) formed in both large and small littermates. Primary fibre size increased from 38 to 70 days gestation after which these fibres declined in diameter. The initial increase in size was largely caused by the development of a region of myofibril free cytoplasm in the centre of these fibres giving them a tubular shape which was lost in the second half of gestation due to their collapse. Primaries in both large and small were of equal size at 38 days but a significantly greater maximum size was attained by primaries in large littermates (23 ^ m) compared to the small (17 ^ m). This size difference was due to differences in the extent of the myofibril free region, described above, which could account for 60% of the fibre diameter in large as opposed to only 30% in the small.Secondary fibres were formed between 54 and 85 days gestation and there appeared to be no difference in the duration of hyperplasia between the large and small animal. This generation of fibres was found to be formed only on the surface of primary fibres. Secondary fibres showed little change in size until 100 days when hypertrophy started. There was a small but significant difference in their diameter between large and small (7 f* m and 6 j* m respectively for most of gestation). Comparison of the secondary/primary fibre ratio during gestation showed that the difference in fibre number mentioned above was due to fewer secondaries forming on each primary in the small as compared with the large littermate.A hypothesis was put forward that a difference in the available surface area of primary fibres, caused by their different diameters, had resulted in fewer secondaries forming on the surface of primary fibres in small littermates. Sections were taken of the m. semitendinosus of all 13 members of a litter of 70 days gestation. A significant correlation between fetal weight and primary fibre diameter was found, together with a significant correlation between primary fibre diameter and the secondary/primary fibre ratio.Frozen sections of the m. semitendinosus were histochemically stained for Adenozine triphosphatase after acid preincubation. From ^6 days until 102 days only primary fibres in the deep region of the muscle were stained, indicating that there were presumptive slow twitch fibres. After 102 days secondary fibres immediately adjacent to the above primary fibres also started to be stained so that by birth, characteristic bundles of slow twitch fibres were seen in the deep region.3. BiochemistryAssays for DNA, RNA and two fractions of protein (sacroplasmic and fibrillar) were carried out on the semitendinosus muscles of large and small littermates. All the above parameters increased during gestation but significantly lower total amounts were found in small littermates. No significant difference could however be found between large and small in the concentrations of these constituents. DNA concentration increased until 100 days after which it declined. The concentration of nuclei (measured from sections) described a similar pattern but showed a significantly higher concentration of nuclei in small littermates. RNA concentration declined with age while protein concentration, after an initial decline, increased until term. Some of these results were discussed in terms of the histology reported in the previous section. Towards term smaller fetuses had significantly higher sacroplasmic/fibrillar protein ratios which is believed to be a sign of malnutrition. RNA/DNA ratios showed an initial decline but were constant for the rest of gestation. Protein/DNA ratios also showed a similar pattern with an initial decline followed by a constant level until it increased after 100 days. No significant difference could be demonstrated between large and small in the results for either ratio.The conclusion of this project was that the smallest littermates were growth retarded due to prenatal malnutrition. The most important effect of this was the failure of small littermates to form as many secondary fibres as their large siblings. A theory linking this to their low primary fibre size was presented. Other factors affecting fibre number were discussed together with the effect this has on postnatal growth and performance

Expression of the proteolysis-inducing factor core peptide mRNA is upregulated in both tumour and adjacent normal tissue in gastro-oesophageal malignancy

Gastro-oesophageal cancer is associated with a high incidence of cachexia. Proteolysis-inducing factor (PIF) has been identified as a possible cachectic factor and studies suggest that PIF is produced exclusively by tumour cells. We investigated PIF core peptide (PIF-CP) mRNA expression in tumour and benign tissue from patients with gastro-oesophageal cancer and in gastro-oesophageal biopsies for healthy volunteers. Tumour tissue and adjacent benign tissue were collected from patients with gastric and oesophageal cancer (n=46) and from benign tissue only in healthy controls (n=11). Expression of PIF-CP mRNA was quantified by real-time PCR. Clinical and pathological information along with nutritional status was collected prospectively. In the cancer patients, PIF-CP mRNA was detected in 27 (59%) tumour samples and 31 (67%) adjacent benign tissue samples. Four (36%) gastro-oesophageal biopsies from healthy controls also expressed PIF-CP mRNA. Expression was higher in tumour tissue (P=0.031) and benign tissue (P=0.022) from cancer patients compared with healthy controls. In the cancer patients, tumour and adjacent benign tissue PIF-CP mRNA concentrations were correlated with each other (P<0.0001, r=0.73) but did not correlate with weight loss or prognosis. Although PIF-CP mRNA expression is upregulated in both tumour and adjacent normal tissue in gastro-oesophageal malignancy, expression does not relate to prognosis or cachexia. Post-translational modification of PIF may be a key step in determining the biological role of PIF in the patient with advanced cancer and cachexia

Liver Manipulation Causes Hepatocyte Injury and Precedes Systemic Inflammation in Patients Undergoing Liver Resection

Contains fulltext : 51690.pdf (publisher's version ) (Closed access)BACKGROUND: Liver failure following liver surgery is caused by an insufficient functioning remnant cell mass. This can be due to insufficient liver volume and can be aggravated by additional cell death during or after surgery. The aim of this study was to elucidate the causes of hepatocellular injury in patients undergoing liver resection. METHODS: Markers of hepatocyte injury (AST, GSTalpha, and L-FABP) and inflammation (IL-6) were measured in plasma of patients undergoing liver resection with and without intermittent inflow occlusion. To study the separate involvement of the intestines and the liver in systemic L-FABP release, arteriovenous concentration differences for L-FABP were measured. RESULTS: During liver manipulation, liver injury markers increased significantly. Arterial plasma levels and transhepatic and transintestinal concentration gradients of L-FABP indicated that this increase was exclusively due to hepatic and not due to intestinal release. Intermittent hepatic inflow occlusion, anesthesia, and liver transection did not further enhance arterial L-FABP and GSTalpha levels. Hepatocyte injury was followed by an inflammatory response. CONCLUSIONS: This study shows that liver manipulation is a leading cause of hepatocyte injury during liver surgery. A potential causal relation between liver manipulation and systemic inflammation remains to be established; but since the inflammatory response is apparently initiated early during major abdominal surgery, interventions aimed at reducing postoperative inflammation and related complications should be started early during surgery or beforehand

The influence of systemic inflammation, dietary intake and stage of disease on rate of weight loss in patients with gastro-oesophageal cancer

Although weight loss is often a dominant symptom in patients with upper gastrointestinal malignancy, there is a lack of objective evidence describing changes in nutritional status and potential associations between weight loss, food intake, markers of systemic inflammation and stage of disease in such patients. Two hundred and twenty patients diagnosed with gastric/oesophageal cancer were studied. Patients underwent nutritional assessment consisting of calculation of body mass index, measurement of weight loss, dysphagia scoring and estimation of dietary intake. Serum acute-phase protein concentrations were determined by enzyme-linked immunosorbent assay. In all, 182 (83%) patients had lost weight at diagnosis (median loss, 7% body weight). Weight loss was associated with poor performance status, advanced disease stage, dysphagia, reduced dietary intake and elevated serum C-reactive protein (CRP) concentrations. Multiple regression identified dietary intake (estimate of effect, 38%), serum CRP concentrations (estimate of effect, 34%) and stage of disease (estimate of effect, 28%) as independent variables in determining degree of weight loss. Mechanisms other than reduced dietary intake or mechanical obstruction by the tumour appear to be involved in the nutritional decline in patients with gastro-oesophageal malignancy. Recognition that systemic inflammation plays a role in nutritional depletion may inform the development of appropriate therapeutic strategies to ameliorate weight loss, making patients more tolerant of cancer-modifying treatments such as chemotherapy

The SM and NLO multileg working group: Summary report

This report summarizes the activities of the SM and NLO Multileg Working Group of the Workshop "Physics at TeV Colliders", Les Houches, France 8-26 June, 2009.Comment: 169 pages, Report of the SM and NLO Multileg Working Group for the Workshop "Physics at TeV Colliders", Les Houches, France 8-26 June, 200

Nutrition intervention is beneficial in oncology outpatients receiving radiotherapy to the gastrointestinal or head and neck area

Background: Malnutrition occurs frequently in patients with cancer of the gastrointestinal or head and neck area and can lead to negative outcomes. Objective: To determine the impact of early and intensive nutrition intervention on body weight, body composition, nutritional status, global quality of life and physical function compared to usual practice in oncology outpatients receiving radiotherapy to the gastrointestinal or head and neck area. Design: Outpatients commencing at least 20 fractions of radiotherapy to the gastrointestinal or head and neck area were randomised to receive intensive, individualised nutrition counselling by a dietitian using a standard protocol and oral supplements if required, or the usual practice of the centre (general advice and nutrition booklet). Outcome parameters were measured at baseline and four, eight, and twelve weeks after commencing radiotherapy using valid and reliable tools. Results: Sixty patients (51M;9F; mean age 61.9 yr +/- 14.0) were randomised to receive either nutrition intervention (n=29) or usual care (n=31). The nutrition intervention group had statistically smaller deteriorations in weight (p < 0.001), nutritional status (p = 0.020) and global quality of life (p = 0.009) compared with those receiving usual care. Clinically, but not statistically significant differences in fat-free mass were observed between the groups (p = 0.195). Conclusions Early and intensive nutrition intervention appears beneficial in terms of minimising weight loss, deterioration in nutritional status, global quality of life and physical function in oncology outpatients receiving radiotherapy to the gastrointestinal or head and neck area. Weight maintenance in this population leads to beneficial outcomes and suggests that this, rather than weight gain, may be a more appropriate aim of nutrition intervention

Signal transduction pathways involved in proteolysis-inducing factor induced proteasome expression in murine myotubes

The proteolysis-inducing factor (PIF) is produced by cachexia-inducing tumours and initiates protein catabolism in skeletal muscle. The potential signalling pathways linking the release of arachidonic acid (AA) from membrane phospholipids with increased expression of the ubiquitin-proteasome proteolytic pathway by PIF has been studied using C2C12 murine myotubes as a surrogate model of skeletal muscle. The induction of proteasome activity and protein degradation by PIF was blocked by quinacrine, a nonspecific phospholipase A2 (PLA2) inhibitor and trifluroacetyl AA, an inhibitor of cytosolic PLA2. PIF was shown to increase the expression of calcium-independent cytosolic PLA2, determined by Western blotting, at the same concentrations as those inducing maximal expression of 20S proteasome α-subunits and protein degradation. In addition, both U-73122, which inhibits agonist-induced phospholipase C (PLC) activation and D609, a specific inhibitor of phosphatidylcholine-specific PLC also inhibited PIF-induced proteasome activity. This suggests that both PLA 2 and PLC are involved in the release of AA in response to PIF, and that this is important in the induction of proteasome expression. The two tyrosine kinase inhibitors genistein and tryphostin A23 also attenuated PIF-induced proteasome expression, implicating tyrosine kinase in this process. PIF induced phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) at the same concentrations as that inducing proteasome expression, and the effect was blocked by PD98059, an inhibitor of MAPK kinase, as was also the induction of proteasome expression, suggesting a role for MAPK activation in PIF-induced proteasome expression. © 2003 Cancer Research UK