Biomedical subjects

D R Campion

Publications and source records attributed to D R Campion.

At least 37 records · Page 2Linked to original sources

PubMed1986

Adipocyte development in primary rat cell cultures: a scanning electron microscopy study.

This study utilized scanning electron microscopy (SEM) techniques to observe primary cultures of stromal-vascular (SV) cells derived from postnatal rat inguinal adipose tissue. Cells were grown on collagen-coated, fibronectin-coated, or uncoated glass coverslips. Coverslips were normally fixed in glutaraldehyde, osmium tetroxide, dehydrated, and critical-point-dried. Other coverslips were frozen in isopentane (cooled in LN2) and dried or fixed in Baker's formalin for demonstration of inosine diphosphatase (IDPase) by X-ray microprobe analysis (XRMA). Adipocyte morphologies were similar on all substrates. At 2 days of culture, actin cables were detected extending from developing adipocytes. No difference in actin cable structure, cellular shape, or lipid accumulation was observed among the different substrates. Some stromal cells did not accumulate lipid but proliferated into a multilayer by 9 days in culture. Inosine diphosphatase was detected in the Golgi apparatus of developing adipocytes utilizing the technique of XRMA. This study demonstrates the potential for using SEM and XRMA techniques to define morphological features and cytochemical markers of adipocytes in vitro and the response of primary cultured rat SV cells to other attachment substrates.

Adipose Tissue↗

PubMed1986

Development of semitendinosus muscle in pig fetuses with spinal cord lesions.

The effect of upper motor neuron regulation on the development of the semitendinosus muscle was studied in the fetus. A region of the fetal spinal cord at the level of the upper cervical vertebrae was destroyed by cauterization at 45 days of gestation. Fetuses with intact spinal cords served as controls. One cauterized fetus and one control fetus were obtained from each of six crossbred sows at 110 days of gestation. From each fetus one semitendinosus muscle was removed for histochemistry and the contralateral muscle was removed, weighed and utilized for biochemical analyses. Body weights and muscle weights were not significantly different (p greater than 0.05) between the two groups. Transverse sections (cryostat) of muscle were stained for lipid and the following enzymes: acid ATPase, NADH-TR, and esterase. Lipid and enzyme cytochemistry showed that sections from cauterized and control fetuses had identical fiber type patterns. Motor endplates, as studied with esterase reactions, were not affected by spinal cord cauterization. Mean values for percentage of muscle dry weight, DNA, RNA, protein, glycogen content and minimum fiber diameters were similar for cauterized and control fetuses (p greater than 0.05). These data illustrate that in the porcine fetus the central nervous system proximal to the alpha-motoneuron exerts little control over muscle cell development.

Adenosine Triphosphatases↗

PubMed1986

Effect of growth hormone-secreting tumours on skeletal muscle cellularity in the rat.

Tumours secreting GH (GH1) or GH plus prolactin (GH3) were induced in young (1-week-old) and mature (17-week-old) female Wistar-Furth rats. Young animals were killed at 11 weeks and mature rats at 30 weeks of age. Induction of tumours increased serum GH concentrations and body and soleus muscle weights when compared with those of control rats. The soleus and extensor digitorum longus (EDL) muscles were examined in transverse section by electron microscopy. The percentages of myofibres with myonuclei and with satellite cell nuclei present in both the soleus and EDL muscles were generally greater in young rats with tumours than in young control rats. The percentage of myofibres in the EDL muscle with myonuclei present was higher in mature rats with GH1 tumours compared with age-matched controls. The presence of tumours did not affect the number of fibres in the soleus muscle of either young or mature rats. It was concluded that increased GH concentrations increased muscle weight by increasing the DNA content of myofibres and by myofibre hypertrophy. The rate of proliferation of satellite cells apparently exceeded the rate of incorporation of daughter nuclei into the fibres of the young tumour-bearing rats when compared with that of young controls. Thus, the factors regulating satellite cell proliferation and nuclear incorporation into the myofibre do not appear to be directly coupled.

Animals↗

PubMed1986

Effect of growth hormone-secreting tumors on body composition and feed intake in young female Wistar-Furth rats.

Growth hormone (GH) was elevated in young growing, intact female Wistar-Furth rats bearing growth hormone (GH1) or growth hormone and prolactin (GH3) secreting tumors. Animals were injected with GH1 or GH3 cells at 1 wk of age. Total feed intake was measured for the 8-wk period from weaning until killed at 11 wk of age. Animals were fed a commercial chow diet throughout the trial. Body composition and composition of the liver and tibialis anterior muscle were determined. Tumor-bearing rats were about 65% heavier than control rats at 11 wk of age: most of the difference in body weight gain was obtained during the last 4 wk of the trial. Total feed intake during the 8 wk after weaning was increased in both GH1 and GH3 tumor-bearing rats when compared with controls. Overall feed efficiency (grams feed consumed/gram body weight gain) was improved in tumor-bearing animals when compared with controls. The GH1 tumor-bearing rats were slightly hyperphagic during wk 8, 9 and 10 (grams feed consumed/gram body weight) when compared with controls. The total amount of body dry matter, protein and ash was increased in tumor-bearing rats when compared with controls. There was no effect on total body fat. Tumor-bearing rats had increased liver weight and increased fat, protein, RNA, DNA and dry matter content when compared with controls. Tumor induction increased the weight, total RNA and total fat content of the tibialis anterior muscle when compared with controls. There was no effect on muscle protein content.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Effect of fasting neonatal piglets on blood hormone and metabolite profiles and on skeletal muscle metabolism.

A pair of weight-matched piglets was identified at birth in each of six litters. One member of the pair was allowed to suckle for 24 h while the other was fasted. Serum concentrations of insulin, thyroxine (T4), somatomedin-C (RIA) and somatomedin-like activity (bioassay) were non-detectable or lower in non-suckled piglets when compared with suckled piglets. The converse situation was found for serum growth hormone (GH) levels, i.e., GH levels were higher (P less than .01) in non-suckled piglets. Triiodothyronine (T3) concentration was not influenced by nutritional status. Serum concentrations of fructose and of free fatty acids were not influenced by fasting (P greater than .05), but glucose and triacylglycerol serum levels were lower (P less than .01, P less than .05, respectively) in the non-suckled group. The biceps femoris muscle of the non-suckled group weighed less (P less than .05) and contained less RNA (P less than .01) and protein (P less than .07), but DNA and dry matter were similar between groups. Rates of glucose oxidation to CO2 (with [1-14C] glucose tracer, P less than .01; with [6,14C] glucose tracer, P less than .09) and incorporation into glycogen (P less than .01) and of palmitate esterification into triacylglycerol (P less than .01) were reduced by fasting. However, the rates of glycolytic flux and of palmitate oxidation to CO2 (expressed per mg protein) were not affected by fasting. The rate of glucose incorporated into glycogen was reduced (P less than .05) by the presence of palmitate in the muscle of suckled piglets. A dose-dependent decrease in somatomedin-like activity with increased concentration of serum from non-suckled piglets in the cartilage disc bioassay suggested that the production of growth inhibitors accompanied the loss of nutrient availability. The biceps femoris muscle responded to the fast by conserving fatty acid for oxidation as an energy source rather than for incorporation into triacylglycerol or phospholipid. The reduction in glucose oxidation to CO2, but maintenance of glycolytic flux rates, may be important to production of lactate, which can be used by the brain and heart as an energy source. It was suggested that the metabolic adaptations of pig skeletal muscle to the fasted state may be critical to survival.

Animals↗

PubMed1986

Substrate utilization by fetal pig skeletal muscle.

The ability of fetal pig skeletal muscle (biceps femoris) to metabolize glucose, fructose, lactate, acetate and palmitate in vitro was examined at 70, 90 and 110 d of gestation. Even though succinate dehydrogenase activity increased as fetal age increased (P less than .01), the rate of oxidation of glucose, fructose, acetate and palmitate to CO2 was not influenced by fetal age (P greater than .05), but each rate was dose-dependent (P less than .01). At higher concentration, lactate oxidation to CO2 proceeded at a faster rate in the muscle of 70-d fetuses when compared with 90- or 110-d fetuses. Muscle glycogen content increased (P less than .01) from 70 to 110 d of gestation. The rate of glucose incorporation into glycogen increased over this same time frame (P less than .06). Glucose-6-phosphate dehydrogenase activity did not change with age when activity was expressed per unit wet weight of muscle (P greater than .05). The ratio [1-14C]glucose/[6-14C]glucose oxidized to CO2 was independent of age and substrate concentration, and indicated significant pentose cycle activity in fetal muscle. Incorporation of lactate and palmitate into phospholipid was greatest at 70 d of gestation, a time period that coincides with establishment of mature muscle fiber number and fiber hypertrophy. The rate of palmitate incorporation into triacylglycerol was dependent on concentration of substrate (P less than .01) but not on age (P greater than .05). The rate of fructose oxidation to CO2 was lower than the rate for glucose, lactate and acetate when compared at similar concentrations. Acetate carbons were not incorporated into free fatty acids or lipid.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗

PubMed1986

Adipose tissue cellularity and growth characteristics of unselected and selected broilers: implications for the development of body fat.

Chicks from large and small eggs were used to increase body weight range within samples of unselected Athens-Canadian (AC) and commercial Cobb (C) broilers. At 54 days of age, representatives of each sex and broiler stock obtained from the large and small eggs were killed. Indices of whole body, muscle, fat, and bone growth were taken. Samples of abdominal fat were fixed with osmium tetroxide for electronic quantification of adipocyte number and size distribution. Broiler stock, egg size, and sex affected all indices of muscle and bone growth on an absolute basis, but only broiler stock significantly affected abdominal fat pad development. Muscle and fat weight, expressed as a proportion of body weight, were larger in C broilers. Abdominal adipocyte number was greater in C than AC (126.0 +/- 10.0 vs. 90.9 +/- 7.7 million, P less than .01), but the greater adiposity of C was associated with an increase in adipocyte size. If the mean adipocyte volume of C (120.4 +/- 8.5 pl) was reduced to the mean adipocyte volume of AC (53.8 +/- 6.5 pl), proportional weight of the abdominal pad of C would have been smaller than proportional pad weight of AC. The problem of excessive abdominal fat deposition in the selected broiler stock appears related to factors that affect control of adipocyte size and body composition.

Adipose Tissue↗

PubMed1986

Skeletal muscle cellularity and histochemistry in young lean and obese pigs.

The cellularity and histochemistry of the semitendinosus muscle was studied in lean and obese pigs at 14 days of age. Muscles from lean animals had lower (P less than .05) muscle weights and minimum fiber diameters and had reduced (P less than .05) percentages of dry matter and protein when contrasted to obese muscles. Concentrations of RNA and glycogen were independent of animal strain but DNA levels were severely depressed (P less than .01) in obese muscle. Histochemistry for lipid, NADH-TR, acid ATPase, esterase and glycogen (PAS) indicated no strain effects. Regardless of strain, sections from larger animals showed histochemical patterns indicative of more mature muscles. These studies demonstrate abnormalities in muscle cellular characteristics in the young obese animal. Furthermore, these abnormalities may accelerate muscle maturation and hasten the fattening phase of growth.

Adenosine Triphosphatases↗

PubMed1986

Effect of growth hormone-secreting tumors on adipose tissue cellularity in young and mature rats.

Growth hormone, GH1, or growth hormone and prolactin, GH3, secreting tumors were induced in 1 week old female Wistar-Furth rats and 17 week old female Wistar-Furth rats. At 11 or 30 weeks of age the parametrial fat pad (PFP) was weighed and a portion fixed with osmium tetroxide for cell quantitation by a Coulter counter technique. Tumor induction increased the body weight of both young and mature rats by 50 and 100% respectively when compared to age matched controls. Serum GH was elevated about 100 fold in both young and old treated rats when compared to controls. Tumor induction decreased the weight of the PFP in both young and old rats when compared to controls but the effect was only significant in the GH3 tumor bearing rats weights. The PFP made up a much smaller percentage of the body weight in all the treated groups when compared to respective age matched controls. Mean PFP adipocyte number was not affected by treatment or age. Tumor induction decreased the mean diameter and mean volume of adipocytes in both young and old rats of both treatment groups compared to age matched controls. The distribution of adipocytes by cell diameter was shifted toward smaller cells in the tumor-bearing rats. In conclusion, induction of GH1 or GH3 tumors elevated serum GH concentrations, increased body weight and decreased relative fat pad weight but did not affect adipocyte cell number. Hence, the proposed adipogenic function of GH does not appear to function in this model in vivo.

Adipose Tissue↗

PubMed1985

Plasma hormone levels in growth-retarded rats with dorsomedial hypothalamic lesions.

Rats with lesions in the dorsomedial hypothalamic nuclei (DMNL rats) are hypophagic and growth-retarded. Since previous work had shown normal plasma growth hormone and insulin levels in DMNL rats we investigated the diurnal patterns of these and other hormones involved in growth. Trial 1: Rats received electrolytic DMNL or sham operations (SCON). The DMNL rats exhibited no differences from SCON rats in plasma triiodothyronine (T3), growth hormone (GH), insulin and somatomedin (SM) concentrations, Trial 2: kainic acid, a neurotoxin, was used for lesion production. Again, DMNL rats showed no deficiencies in plasma levels of T3, GH or insulin. Trial 3: In this experiment, diurnal hormone profiles were assessed. The GH profile and mean 24-hour secretion of both DMNL and SCON groups did not differ significantly. Both groups exhibited a diurnal release of T3, with the DMNL rats showing slightly higher levels. Plasma insulin rose after dark, i.e., at the onset of feeding, in SCON but not in DMNL rats; the later have a previously reported disrupted feeding rhythm. Glucose patterns were in keeping with insulin profiles. Controls showed a normal plasma corticosterone rhythm whereas DMNL rats had an altered pattern. The data suggest that deficiencies in the principal anabolic and growth-promoting hormones cannot be responsible for the retarded growth of DMNL rats.

Animals↗

PubMed1985

Enzyme histochemical studies in an ontogeny study of muscle development in Ossabaw and decapitated fetuses: cellular reactions.

Fetuses were decapitated in one uterine horn in each of 14 sows at 45 d of gestation. Control (C) and decapitated (D) fetuses were removed by Caesarean section from three sows at 65 d of gestation (total of 10 D and 10 C fetuses), two sows at 85 d (six D and six C fetuses) and nine sows at 110 d (nine C and nine D fetuses) of gestation (Exp. 1). In Exp. 2, four to six fetuses were removed from each of two Ossabaw (O) gilts and three crossbred (C, Landrace X Yorkshire) gilts at 70 d of gestation, from three C and O gilts at 90 d of gestation and from three C and two O gilts at 110 d of gestation. In Exp. 1, one semitendinosis muscle was removed for histochemistry, whereas the contralateral muscle was removed and weighed. A medial portion of biceps femoris muscle was removed and used for histochemistry in Exp. 2. In both experiments, transverse sections (cryostat) of muscle were stained for lipid, glycogen (PAS) and the following enzymes: acid ATPase, NADH-TR, NADPH-TR, malate dehydrogenase (NAD- and NADP-dependent reactions; MDH), succinate dehydrogenase (SDH), alpha-glycerol phosphate dehydrogenase (with and without NAD; alpha-GPDH), isocitrate dehydrogenase (NAD dependent; ICDH), esterase, lipoprotein lipase and lipase. In Exp. 1, body and muscle weights of the two groups were not significantly different (P greater than .05) at 65 d of gestation, whereas D fetuses were smaller and had lighter weight muscles (P less than .05) at 85 d of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Growth, carcass composition and selected hormone concentrations of restricted-and ad libitum-fed pigs.

Two barrows and two gilts were selected from each of five different crossbred litters and allotted to either ad libitum- or restricted-fed treatments. Pigs fed at a level of 81% ad libitum intake grew slower (P less than .05), had less tenth-rib backfat (P less than .05), more percent muscle (P less than .05), an increased growth hormone (GH) secretion in response to glucose challenge at 50 kg (P less than .05) and decreased insulin secretion in response to glucose challenge at 50 and 100 kg (P less than .05) than ad libitum fed pigs. Hormone secretion response was also significantly affected by weight, with growth hormone decreasing and insulin increasing as pigs grew from 50 to 100 kg. No sex effects of sex X treatment interactions were found for hormone response (P greater than .10). There were no differences between treatments in feed efficiency, total feed intake on test, loin eye area, dressing percentage, or carcass length (P greater than .10). Carcass composition of barrows and gilts was affected differently by restricted nutrient intake.

Animals↗

PubMed1985

Blood parameters and body composition in fetuses from reciprocal crosses of genetically lean and obese swine.

Lines of swine previously selected for either high backfat (obese) or low backfat (lean) were investigated to determine the effect of maternal obesity and the relationship between serum parameters and body composition. Fetal weight, percentage body protein, fat, fat-free organic matter and ash, and serum concentrations of albumin, growth hormone, triiodothyronine, and cortisol were compared in fetuses from straight line and reciprocal crosses at 110 days of gestation. Fetuses from the obese line weighed less but had a greater percentage body protein, fat, and fat-free organic matter than did fetuses from the lean line. Serum concentrations of albumin and triiodothyronine were less whereas those of growth hormone were greater in fetuses from the lean line compared to fetuses from the obese line. Values for these parameters in fetuses from the reciprocal crosses were generally intermediate to those of fetuses from the lean and obese lines. Comparisons of fetuses from the reciprocal and line crosses by linear contrast showed that the observed differences were mainly due to the average genetic effect of individual fetal genotypes and not due to maternal effects. Correlations computed from the residual variance showed a positive relationship between percentage body protein, serum albumin, and triiodothyronine while percentage body fat was not correlated with any of the other traits. Serum growth hormone was negatively correlated with fetal weight. We conclude that there is no apparent maternal effect of obesity or relationship of fetal fat content with any of the other variables measured in these lines of swine at the stage of fetal development at which these determinations were made.

Animals↗

PubMed1985

Fetal hormone and metabolite levels in lean and obese pigs.

Early development changes in hormone levels were investigated in strains of pigs with genetic propensities for excessive lipid deposition. Fetal serum growth hormone was lowest in the preobese pigs (Ossabaw and high backfat). Fetal serum triiodothyronine was significantly elevated in the fetal pigs from obese strains. Fetal serum cortisol was highest in the high backfat pigs. There were no statistically significant differences in fetal serum glucagon. Ossabaw (obese) sows have higher serum glucose levels during gestation than low backfat or high backfat sows. This hyperglycemia is reflected in higher serum glucose levels in 110 day old Ossabaw fetal pigs. High backfat sows have higher serum triglyceride levels that low backfat or Ossabaw sows. The Ossabaw fetal pig has lower serum triglycerides than either the high backfat or the low backfat fetuses. These studies characterize early changes in serum metabolites and hormones in pigs which have the genetic propensity for obesity. At 110 days of gestation these pigs are similar in body at content (less than 1%). It is proposed that the lower level of growth hormone in the preobese fetal pig promoted a lower rate of lean body growth and a higher rate of lipid deposition postnatally.

Adipose Tissue↗

PubMed1984

The muscle satellite cell: a review.

Since the first reports of satellite cells in 1961, considerable knowledge has accumulated concerning their phylogenetic distribution and their location, morphology, and function. There is no doubt that satellite cells are capable of undergoing mitosis and that they have considerable motility. These cells function as the progenitors of the myofiber nuclei that must be added during normal (postnatal) growth of muscle. In muscle undergoing or attempting to undergo regeneration, the satellite cell functions as a myogenic stem cell to produce myoblasts that line up and fuse within the scaffolding of the remnant basal lamina or migrate into the interstitium to produce neofibers . A number of problems remain to be solved concerning the regulation of satellite cell function. At this time it is equivocable whether or not the presumptive myoblast and the satellite cell are functionally identical and at the same stage of myogenic differentiation. Apparently there is species variation in terms of the ability of myotubes from embryonic myogenic cells and satellite cells to synthesize protein. The mechanism(s) by which a wide variety of stimuli activate satellite cells is not known, nor is the mechanism(s) by which satellite cells become inactive during the latter stages of growth and adulthood known. Mitogenic factors are present in damaged muscle; but the specific characteristics of these factors and their mechanism of activation are also unknown. Hormones are certainly involved in the regulation of proliferation and differentiation of myogenic cells, but whether presumptive myoblasts and satellite cells or their myotubes respond similarly to hormones in culture has not been adequately examined. Greater understanding of these mechanisms will increase the possibility of total muscle recovery from severe injury or disease. Such knowledge would also have particular application to the production of meat animals and to a greater understanding of the growth process in general.

Animals↗

PubMed1984

Effect of maternal dietary fat on skeletal muscle cellularity and satellite cell content of the porcine fetus at 110 days of gestation.

Crossbred gilts and sows were fed isocaloric diets that contained 0, 2.3, 12.8 or 29.7% poultry fat beginning at day 80 of gestation. At day 110 of gestation, fetuses were removed by Caesarean section. Maternal dietary fat did not influence fetal weight, sartorius muscle weight, length, composition, cellularity or satellite cell content. It was concluded that feeding diets high in fat during the last trisemester as exercised in this study did not influence the satellite cell content or cellularity of skeletal muscle.

Animals↗

PubMed1984

Effect of fetal decapitation on the composition and metabolic characteristics of pig skeletal muscle.

The effect of fetal decapitation on the compositional and metabolic characteristics of the biceps femoris muscle of the pig was studied. Fetuses were decapitated at 45 days of gestation and sampled at 110 days of gestation. Muscle wet weight was greater and total dry matter was lower in decapitated (D) than in control (C) fetuses. Total muscle triglyceride content was not influenced by decapitation, but the triglyceride concentration was lower in D when compared to C fetuses. Muscle cell number (total muscle DNA) was not influenced by decapitation, but protein/DNA was greater in the muscle of D than C fetuses. Aerobic metabolism, as measured by oxidation of pyruvate, isoleucine, and palmitate to CO2, was not influenced by decapitation. The rate of palmitate esterified and the ratio of palmitate oxidized/esterified was normal in decapitated fetuses. While the tricarboxylic acid cycle appeared to function normally, pentose shunt activity was higher in the decapitated fetal muscle than in control muscle. Although the rate of decarboxylation of leucine was lower in the muscle of D than in C fetuses, the net rate of leucine transaminated was similar between C and D fetuses.

Amino Acids↗

PubMed1984

Effect of maternal diet on skeletal muscle composition and metabolism and on bone dimensions and composition of the fetal pig.

The purpose of the present study was to determine the effect of addition of fat to sow diets on selected muscle and bone traits of the fetus. Crossbred dams were assigned to receive one of four dietary treatments at 80 d of gestation. Percentage added poultry fat in the diet was 0, 2.3, 12.7 or 29.6%. Isocaloric-isonitrogenous diets (7,000 kcal ME) were fed once daily. At 110 d of gestation, sows were anesthetized with fluothane and nitrous oxide. Fetuses were removed by Caesarean section. Fetal body weight, biceps femoris muscles and femur wet weights and blood (concentration of protein, free fatty acids and triacylglycerol), muscle (percentage dry matter, concentration of DNA, RNA, protein and lipid) and bone (percentage dry matter, lipid, ash and length) traits were not influenced by maternal dietary fat content. The rates of oxidation of palmitate and of lipid to CO2 and the rates of incorporation of palmitate into triacylglycerol and into phospholipid by fetal pig muscle also were not influenced by maternal dietary fat content. It was suggested that fetal skeletal muscle can mobilize glycogen and, to a limited extent, lipid stores.

Animals↗