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

Weekly high-resolution multi-spectral and thermal uncrewed-aerial-system mapping of an alpine catchment during summer snowmelt, Niwot Ridge, Colorado

Alpine ecosystems are experiencing rapid change as a result of warming temperatures and changes in the quantity, timing and phase of precipitation. This in turn impacts patterns and processes of ecohydrologic connectivity, vegetation productivity and water provision to downstream regions. The fine-scale heterogeneous nature of these environments makes them challenging areas to measure with traditional instrumentation and spatiotemporally coarse satellite imagery. This paper describes the data collection, processing, accuracy assessment and availability of a series of approximately weekly-interval uncrewed-aerial-system (UAS) surveys flown over the Niwot Ridge Long Term Ecological Research site during the 2017 summer-snowmelt season. Visible, near-infrared and thermal-infrared imagery was collected. This unique series of 5–25 cm resolution multi-spectral and thermal orthomosaics provides a unique snapshot of seasonal transitions in a high alpine catchment. Weekly radiometrically calibrated normalised difference vegetation index maps can be used to track vegetation health at the pixel scale through time. Thermal imagery can be used to map the movement of snowmelt across and within the near sub-surface as well as identify locations where groundwater is discharging to the surface. A 10 cm resolution digital surface model and dense point cloud (146 points m−2) are also provided for topographic analysis of the snow-free surface. These datasets augment ongoing data collection within this heavily studied and important alpine site; they are made publicly available to facilitate wider use by the research community. Datasets and related metadata can be accessed through the Environmental Data Initiative Data Portal, https://doi.org/10.6073/pasta/dadd5c2e4a65c781c2371643f7ff9dc4 (Wigmore, 2022a), https://doi.org/10.6073/pasta/073a5a67ddba08ba3a24fe85c5154da7 (Wigmore, 2022c), https://doi.org/10.6073/pasta/a4f57c82ad274aa2640e0a79649290ca (Wigmore and Niwot Ridge LTER, 2021a), https://doi.org/10.6073/pasta/444a7923deebc4b660436e76ffa3130c (Wigmore and Niwot Ridge LTER, 2021b), https://doi.org/10.6073/pasta/1289b3b41a46284d2a1c42f1b08b3807 (Wigmore and Niwot Ridge LTER, 2022a), https://doi.org/10.6073/pasta/70518d55a8d6ec95f04f2d8a0920b7b8 (Wigmore and Niwot Ridge LTER, 2022b). A summary of the available datasets can be found in the data availability section below.</p

Induction of cachexia in mice by a product isolated from the urine of cachectic cancer patients.

Urine from cancer patients with weight loss showed the presence of an antigen of M(r) 24,000 detected with a monoclonal antibody formed by fusion of splenocytes from mice with cancer cachexia. The antigen was not present in the urine of normal subjects, patients with weight loss from conditions other than cancer or from cancer patients who were weight stable or with low weight loss (1 kg month(-1)). The antigen was present in the urine from subjects with carcinomas of the pancreas, breast, lung and ovary. The antigen was purified from urine using a combination of affinity chromatography with the mouse monoclonal antibody and reversed-phase high-performance liquid chromotography (HPLC). This procedure gave a 200,000-fold purification of the protein over that in the original urine extract and the material isolated was homogeneous, as determined by silver staining of gels. The N-terminal amino acid sequence showed no homology with any of the recognized cytokines. Administration of this material to mice caused a significant (P<0.005) reduction in body weight when compared with a control group receiving material purified in the same way from the urine of a normal subject. Weight loss occurred without a reduction in food and water intake and was prevented by prior administration of the mouse monoclonal antibody. Body composition analysis showed a decrease in both fat and non-fat carcass mass without a change in water content. The effects on body composition were reversed in mice treated with the monoclonal antibody. There was a decrease in protein synthesis and an increase in degradation in skeletal muscle. Protein degradation was associated with an increased prostaglandin E2 (PGE2) release. Both protein degradation and PGE2 release were significantly reduced in mice pretreated with the monoclonal antibody. These results show that the material of M(r) 24,000 present in the urine of cachectic cancer patients is capable of producing a syndrome of cachexia in mice

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

The presence of the proteolysis-inducing factor in urine does not predict the malignancy of a pancreatic tumour

BACKGROUND: The proteolysis-inducing factor (PIF) was identified as a tumour product in various gastrointestinal cancers. A previous study in pancreatic cancer patients suggested PIF expression as a tumour marker, which is not related to tumour size. We hypothesized that PIF could be a useful marker to exclude benign pancreatic tumors, as chronic pancreatitis with a pancreatic mass. METHODS: Urine of patients with a pancreatic mass of uncertain malignancy was investigated for PIF expression by Western blot. Sufficient urine protein for analysis was available in 59 patients. The diagnosis was established by histology in 54 patients and by follow up in five patients with chronic pancreatitis. In addition, serum CA19-9 was measured. RESULTS: The sensitivity (specifity) for the detection of a malignant pancreatic tumour was 90% (75%) and 54% (71%) for CA19-9 and PIF, respectively. The sensitivity (specifity) for the distinction of pancreatic cancer from chronic pancreatitis was 89% (80%) and 57% (63%) for CA19-9 and PIF, respectively. CONCLUSION: Evaluation of PIF in urine is of no diagnostic value in patients with a pancreatic mass of unknown malignancy