Search PubMed⌕ Search

Biomedical subjects

M L Fiorotto

Publications and source records attributed to M L Fiorotto.

At least 55 records · Page 3Linked to original sources
PubMed1993

A semiautomatic device for feeding liquid milk-replacer diets to infant pigs.

We describe the design and use of a device that enables the semiautomatic feeding of various quantities of liquid, milk-replacer diet. The apparatus consists of a programmable fraction collector (with attachments for preparative work) driven by a high-flow peristaltic pump. To reduce bacterial growth and lipid oxidation of the liquid diet, we kept the milk-replacer in an ice bath and bubbled a slow stream of nitrogen through it at all times. The liquid diet was kept in suspension by continuous recirculation and agitation. The device can be used to dispense prespecified amounts of either the same volume of feed, or a different volume to each of two groups of animals at regular intervals over 24 h; alternatively, by using the time-windows feature of the fraction collector, up to 11 different volumes can be dispensed to 11 animals. We present results of a preliminary trial in which we used the equipment to feed 11 pigs, weaned at 1 d of age, for 11 d. Daily maintenance and programming of two systems, including diet preparation and pig weight measurements, were accomplished in approximately 90 min. The feeder is simple to program and enables the feed intake of the pigs to be adjusted accurately for individual BW on a daily basis. The pigs had no diarrhea and grew well on the rations allocated to them.

Animal Feed↗
PubMed1992

Neonatal genetically lean and obese pigs respond differently to dietary cholesterol.

The impact of cholesterol exposure in early life on later cholesterol metabolism is not clearly understood. Sixteen newborn genetically lean and obese pigs were fed 0 or 5.0 g cholesterol/kg diet (0 or 0.5%) (liquid diets for 12 d, dry diets thereafter) for 33 d, after which they were all fed 10.0 g cholesterol/kg diet (1.0%) for 23 d. All animals were killed on d 56 and whole-body protein, fat and water were determined on the ground carcass. Dietary cholesterol had no consistent effect on growth rates or body composition. Mean fat content of lean pigs was 15.1% compared with 22.7% for obese pigs; corresponding values were 14.8 and 14.4% for protein and 65.5 and 58.3% for water. Concentrations of plasma total cholesterol, HDL cholesterol and apolipoproteins B and A-1 were increased by 0.5% dietary cholesterol in obese but not in lean piglets, although dietary cholesterol caused HDL and LDL size distribution profiles to shift toward larger-sized components in both strains. Plasma total cholesterol and apolipoprotein B concentrations rose two- to eightfold in all groups after the 1% cholesterol diet was consumed; these changes were accompanied by shifts in LDL and HDL size distribution profiles towards larger-sized components. With 1.0% cholesterol in the diet of all groups, HDL cholesterol concentration increased by approximately 50% in both groups of lean pigs and in obese pigs previously fed cholesterol, but did not increase further in obese pigs previously fed 0.5% cholesterol. The magnitude of the hypercholesterolemic response in lean pigs was blunted by previous exposure to 0.5% dietary cholesterol, but the response was accentuated in obese animals that had been previously exposed to 0.5% dietary cholesterol. These data provide evidence that genetic differences between obese and lean pigs affect their serum lipoprotein responses to high cholesterol intake.

Animals↗
PubMed1992

Hepatic protein synthesis in suckling rats: effects of stage of development and fasting.

We studied the developmental changes in hepatic protein synthesis in suckling rats between postpartum d 1 and 28 and investigated the effect of fasting for 10 or 18 h on hepatic protein turnover at postpartum d 5, 10, 16, and 28. Fractional protein synthesis rates (KS, %/d) were measured in vivo using a flooding dose of L-[4-3H]phenylalanine. Although hepatic KS and translation efficiency (protein synthesis/unit RNA) were significantly higher at postpartum d 28 than d 1, the pattern of change was biphasic: KS and translational efficiency were higher at d 10 and 28 than at d 5 and 16. The largest increase in KS and translational efficiency occurred during the period normally associated with weaning (between postpartum d 16 and 28). At all stages of development, the KS and translational efficiency in fasted rats were significantly lower than those in control (fed) rats, although the relative decline in both measurements was largest at postpartum d 10. The absolute rates of hepatic protein synthesis declined to similar levels on d 5, 10, and 16 after 10 h of fasting and changed little after 18 h of fasting; this level was significantly higher at postpartum d 28. Our results suggest that postnatal development in suckling rats was marked by a biphasic pattern in the rates of hepatic protein synthesis, which increased during the neonatal and weaning periods. The relative changes in the synthesis and loss of hepatic protein in response to fasting were greater during the neonatal than during the late suckling and weaning periods.

Age Factors↗
PubMed1991

Stage of development and fasting affect protein synthetic activity in the gastrointestinal tissues of suckling rats.

We studied suckling rats from 1 to 28 d of age to determine the normal developmental changes in the protein synthetic activity of gastrointestinal tissue. We also studied the changes that occurred in response to 10 or 18 h of fasting at 5, 10, 16 and 28 d of age. Protein synthesis was measured in vivo using a flooding dose of L-[4-3H]phenylalanine. Fractional protein synthesis rates (FSR, %/d) of stomach and small intestines increased nearly 80% during the period normally associated with weaning (d 18 to 28). Between birth and 28 d, the pancreas FSR increased approximately 6.5-fold from 46 to 302%/d. The increases in stomach, small intestinal and pancreatic FSR were largely due to increases in translational efficiency (gram protein synthesized per gram RNA). At 5, 10, 16 and 28 d postpartum, both the FSR and translational efficiency in pancreatic and small intestinal tissues were decreased after 10 h of fasting; however, measures in stomach tissue were largely unaffected. The magnitude of decline in FSR and translational efficiency in response to fasting was greater during the earlier than in the later stages of development. The results suggest that the FSR in the pancreas, small intestines and stomach of suckling rats increase during the period of development associated with weaning. Fasting affected protein synthetic activity more profoundly in pancreatic and small intestinal tissue in the early stages of development.

Aging↗
PubMed1991

Intake and use of milk nutrients by rat pups suckled in small, medium, or large litters.

We investigated the extent to which the altered weight gain of rat pups suckled in litters of varying sizes (4, 10, and 16 pups/litter) is attributable to differences in milk nutrient intake. Milk intake was estimated from the rate of dilution over 2 days of a dose of 3H2O administered at 4, 8, and 14 days of age after correction for the water and milk carbon deposited in body tissues over the measurement period. Protein and energy intakes were estimated from the volume of milk consumed by individual pups and the composition of milk from each dam. Significant effects of litter size on milk fat and protein concentration were observed. Weight gain was highly correlated with energy intake in pups suckled in litters of 4 and 10 but not 16. These findings were attributed to a higher energy expenditure of pups less than 10 days old suckled in litters of 16; specifically these pups had higher maintenance energy needs than pups suckled in litters of 4 and 10 and a higher energy cost of tissue synthesis. The latter was ascribed to an ability of immature pups to maximize the efficiency of protein utilization, thereby blunting the deleterious effects of a reduced nutrient intake on protein deposition.

Animal Nutritional Physiological Phenomena↗
PubMed1991

Response of muscle protein synthesis to fasting in suckling and weaned rats.

Protein synthetic efficiency (KRNA) is low in immature skeletal muscle of suckling rats and increases toward the end of the suckling period. To determine whether immature skeletal muscle is able to further reduce KRNA in response to fasting, suckling (5, 10, and 16 days of age) and weaned (28 days of age) rats were fed, fasted for 10 h, or fasted for 18 h and injected with a flooding dose of L-[4-3H]phenylalanine for measurement of muscle protein synthesis in vivo. In fed rats, fractional rates of protein synthesis (KS) and protein synthetic capacity decreased during the suckling period. KRNA increased toward the end of the suckling period. In 5-day-old rats, fasting for 10 h produced a 50% decline in KS of extensor digitorum longus and plantaris muscles, but KS did not change further after 18 h of fasting. In older suckled and weaned rats, 10 h of fasting decreased KS of extensor digitorum longus and plantaris muscles 30%; after 18 h of fasting, values had declined to 50% of those in fed animals. The reductions in KS in soleus muscles with 10 and 18 h of fasting were similar to those in other muscles at 5 and 10 days but were less than those in other muscles at 16 and 28 days. Changes in KRNA were similar to those for KS in all muscles from all age groups fasted for 10 and 18 h. Protein synthetic capacity decreased approximately 12% after 18 h of fasting, but this effect did not differ between age groups or muscle types.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxybutyric Acid↗
PubMed1991

Total body electrical conductivity measurements in the neonate.

TOBEC measurements are based on the premise that a conductive object will interact with an electromagnetic field and result in the dissipation of a small quantity of the field's energy. TOBEC instruments provide a measure of this energy loss, which for a given conductor varies according to its size. The conductive component of the body is that part that contains water with dissolved electrolytes, i.e., essentially the FFM. Fat, by definition, is anhydrous and does not contribute to a TOBEC measurement. To interpret TOBEC readings in terms of the quantity of FFM in the body requires the use of a calibration equation that is generated by measuring the FFM of a reference population using an alternative technique and relating this to each individual's TOBEC value. Because no alternative method exists to estimate the FFM of an infant, a calibration equation is used that was generated from measurements of young miniature piglets. The body composition of infants thus derived is consistent with our general understanding of the changes in fat and FFM in human infants in early life. Whether TOBEC can be used as described in premature or older children has yet to be determined. Variations in the composition of the FFM do not seem to compromise the accuracy of the technique. TOBEC measurements are precise, rapid, noninvasive, and safe and cause the subject no discomfort. These features not only make TOBEC a useful tool for the nutritional assessment of a pediatric patient but they also may be a useful diagnostic tool for the clinician.

Adipose Tissue↗
PubMed1991

Body composition in ballet dancers measured by total body electrical conductivity.

The purpose of this study was to describe the body composition of adolescent and young adult ballet dancers using total body electrical conductivity (TOBEC). We studied 112 female and 33 male dancers. The mean ages were 15.0 +/- 2.0 and 18.7 +/- 3.1 yr for females and males, respectively. The mean percent body fat (PBF) values were 20.1 +/- 3.6% for the females and 14.5 +/- 4.2% for the males. Age and pubertal development were not significantly related to PBF in the females. Age and pubertal status were significantly inversely related to PBF in the males. There was no difference in dance history, percent body fat, and abdominal/hip or waist/hip ratios in eumenorrheic vs amenorrheic dancers. Estimated calorie intake indicated that dancers with menstrual abnormalities had lower calorie intake than those with normal menses. This is the largest group of ballet dancers whose body composition has been studied. Our PBF measurements are higher than in previous reports using hydrodensitometry, which may have underestimated body fat by not accounting for the increased bone density in the lower extremities of dancers. Our data suggest that previous measurements of PBF in dancers are underestimates; these new data challenge our concept of PBF values in dancers.

Adipose Tissue↗
PubMed1991

Total body water and fat-free mass in ballet dancers: comparing isotope dilution and TOBEC.

Nine male and seven female high level ballet students had total body water (TBW) measured by two methods: 1) H2(18)O isotope dilution and 2) total body electrical conductivity (TOBEC). TBW from TOBEC measurements was calculated using an equation previously derived from adults, and these new measurements correlated highly with TBW by isotope dilution (r = 0.99, SEE = 0.78 kg). However, the difference between these two methods increased as TBW increased. Therefore, a new equation (ballet equation) was developed which improved the prediction of TBW for individuals (SEE = 0.69 kg) and for which the difference in TBW between isotope dilution and TOBEC was independent of the TBW value. Using age-adjusted hydration constants, the TBW measurements by isotope dilution were converted to fat-free mass, and these values were used to develop an accurate equation for predicting fat-free mass from TOBEC measurements (r = 0.99, SEE = 0.91 kg). In addition, we measured TBW and calculated FFM in ten control adolescents and used these values to develop equations for predicting TBW (r = 0.99, SEE = 1.01 kg) and FFM (r = 0.99, SEE = 1.42 kg) in a combined group of adolescent dancers and non-dancers. Total body water and fat-free mass can be accurately measured in adolescent ballet dancers and non-dancers using TOBEC.

Adipose Tissue↗
PubMed1989

Reliability of fat-free mass estimates derived from total-body electrical conductivity measurements as influenced by changes in extracellular fluid volume.

Our study addresses the concern that the relationship between total-body electrical conductivity (TOBEC) measurements and the fat-free mass (FFM) or total-body water (TBW) of an individual is altered if significant fluid and electrolyte changes occur. Body composition and TOBEC measurements were obtained from 11 healthy miniature piglets before and after an intraperitoneal injection of physiological saline. The procedure expanded the extracellular fluid (ECF) volume by 11.8-34.1%, which represented an average increase in TBW of 7.9%. The linear regressions that related the preinjection and postinjection estimates of TBW or FFM to the corresponding transformed TOBEC signals were the same. Thus, the prediction equations derived for the untreated piglets accurately predicted both TBW and FFM in the piglets whose volume was expanded. These data suggest that prediction equations derived from healthy subjects should be equally valid for subjects with altered fluid status.

Adipose Tissue↗
PubMed1989

Protein turnover in skeletal muscle of suckling rats.

To determine the normal changes in protein turnover of skeletal muscle in vivo during the suckling period of rats, protein synthesis was measured in soleus, plantaris, anterior tibialis, and extensor digitorum longus (EDL) muscles of 1- to 28-day-old rats using a flooding dose of L-[4-3H]phenylalanine. Protein mass of hind-limb muscles increased nearly 100-fold, and RNA increased approximately 20-fold between 1 and 28 days of age. The total amount of protein synthesized per day increased 34-fold. Fractional protein synthesis rates (Ks) decreased two- to threefold between 1 and 28 days postpartum as a result of a decrease in protein synthetic capacity (RNA/protein). Protein synthetic efficiency (total protein synthesized/RNA) increased during this period. Ks were similar among the four muscles at 1-10 days. At 16 days, Ks increased in soleus and plantaris as a result of increases in protein synthetic efficiency; Ks did not increase in anterior tibialis and EDL. These data suggest that, during the suckling period, protein synthetic capacity in skeletal muscles of rats declines, while protein synthetic efficiency increases. The increase in translational efficiency occurred earlier in weight-bearing muscles (soleus, plantaris) than in non-weight-bearing muscles (anterior tibialis and EDL) and was associated with the appearance of mobility.

Aging↗
PubMed1988

Total body water estimated by measuring total-body electrical conductivity.

A second-generation total-body electrical conductivity (TOBEC) instrument for adults (HA-2) was evaluated against isotope dilution of 2H and 18O for its ability to estimate total body water (TBW) in 20 healthy adults. The highest correlation coefficient (0.997) and the lowest standard error of the estimate (0.68 kg) were obtained using the first (FC0) and third (FC2) Fourier coefficients of the transformed TOBEC signals and the variables height (m) times average lean circumference (m) and age (y) in the prediction equation of TBW as follows: TBW (H218O) in kg = 10.8 + (0.0724.FC0) - (0.221.FC2) + (0.0398.age) + (9.2.height.average lean circumference) where average lean circumference is the average of the lean chest, abdomen, and thigh circumferences. The TOBEC instrument for adults provides a suitable alternative for the estimation of TBW.

Adult↗
PubMed1988

Body fat in normal adults estimated by oxygen-18- and deuterium-dilution and by anthropometry: a comparison.

We estimated body fat in 20 normal adults (10 males and 10 females) from 18O- and 2H-dilution spaces and from the equations of Durnin & Womersley and Pollock, Schmidt & Jackson based on skinfold thickness measurements. Differences between methods for body fat estimation were found to be sex-dependent: subsequent analyses indicated significant differences between methods within each sex. Regardless of sex, the highest fat estimates were obtained with the 18O-dilution method, followed by those obtained with the 2H-dilution method or the Durnin & Womersley equation. The lowest fat estimates were obtained using the Pollock, Schmidt & Jackson equation. The 18O-dilution method and the Durnin & Wormersley anthropometric method are both suitable and appropriate for body fat estimation in adults studied under field conditions.

Adipose Tissue↗
PubMed1987

Specific effects of weight loss, protein deficiency and energy deprivation on the water and electrolyte composition of young rats.

Specific effects of weight loss, protein deficiency and energy deprivation on the water and electrolyte content of the body were studied. Longitudinal changes in total body Na and Cl were measured by neutron activation analysis in young rats fed either a low protein diet (LP) ad libitum or a control diet in restricted amounts (ER). Total body Ca was determined to monitor growth of skeletal mass. Four balance periods were defined to represent various stages of protein or energy deprivation. The chemical composition of the rats was determined at the end of the study and compared with that of rats killed at the start of the study. Changes in body composition of LP rats were attributable chiefly to wasting of body cell mass. There was no retention of Na and Cl until severe hypoalbuminemia and edema developed after chronic protein deprivation; at this time, Na and Cl were retained in the same proportion as their molar ratio in extracellular fluid (ECF). The resulting increase in ECF volume accounted for the high total body water values in LP rats. Energy restriction to approximately 80% of maintenance requirements for 20 d resulted in Na retention in a compartment distinct from either the Cl or Ca space. With prolonged ER, there was preferential wasting of cell mass and adipose tissue but relative preservation of the ECF compartment; there was no net retention of Na and Cl, and hydration of fat-free mass was normal. The differences in the body compositions of ER and LP rats suggested that protein and energy deprivation can have separate effects on Na and Cl homeostasis that are distinct from changes induced by a loss of cell mass.

Animals↗
PubMed1987

Total body electrical conductivity measurements: effects of body composition and geometry.

This study used an animal model to analyze the effect of body geometry and chemical composition on the calibration of a total body electrical conductivity (TOBEC) instrument developed to measure the body composition of human infants. The TOBEC signal (adjusted for length) of infant miniature pigs from 10 to 33 days of age correlated highly with their chemically analyzed fat-free mass (FFM; r = 0.998) and total body water contents (TBW; r = 0.998); 95% prediction intervals (approximately +/- 2 SEE) for individual measurements were +/- 0.16 kg FFM and +/- 0.12 liter water. These values were significantly improved (+/- 0.08 kg and +/- 0.06 liter, respectively) by accounting for individual variability in weight/length2. The effect of variations in the composition of FFM on the TOBEC measurements was evaluated by comparing the response of the infant piglets with that of adult rabbits of similar size. The differences in composition, primarily TBW and Na content, were insufficient to alter the electrical properties of FFM appreciably. Thus the TOBEC used under the conditions defined in this study accurately predicted the FFM and TBW content of infant miniature pigs. The calibration derived from the piglets will be applicable to the interpretation of the TOBEC measurements of human infants provided their FFM is of comparable shape to that of the piglets. Differences in composition are likely to be of consequence only if the proportion of fat within the FFM and the FFM density are widely divergent. This, however, does not appear to be the case.

Animals↗
PubMed1987

Fat-free mass and total body water of infants estimated from total body electrical conductivity measurements.

Total body electrical conductivity measurements can be used in conjunction with suitable calibration curves to quantitate fat-free mass and total body water. A study was designed to evaluate whether calibration curves, derived from miniature piglets, can be used to translate total body electrical conductivity measurements of human infants into estimates of total body water and fat-free mass. Thirty-four, healthy 2-, 4-, 8-, and 12-wk-old infants were studied. A comparison of the physical dimensions of infants and piglets indicated no large discrepancies in their body geometries that would invalidate the calibration from this standpoint. Estimates of fat-free mass, fat, and total body water were evaluated by comparison with the body composition of reference infants of comparable description. There was excellent agreement between the total body electrical conductivity-derived estimates and reference body composition values, suggesting that the calibration procedure is adequate. Thus, the total body electrical conductivity technique can be used to estimate the body composition of normal young infants without subjecting them to risk or discomfort.

Adipose Tissue↗