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Biomedical subjects

J B Morgan

Publications and source records attributed to J B Morgan.

At least 73 records · Page 4Linked to original sources
PubMed1991

Using calcium chloride injection to improve tenderness of beef from mature cows.

The objective of this investigation was to determine the effect of calcium chloride (CaCl2) injection on Warner-Bratzler shear force (WBS), sensory panel ratings, and collagen traits of mature cow beef. Within 30 min of exsanguination, subprimals (top round, TR; top sirloin, TS; strip loin, SL) from alternate sides of the carcass were injected with a .3 M CaCl2 solution (10% of the subprimal weight) and aged for 1, 7, or 14 d. The corresponding cold-boned cuts of the other side served as a control. Injecting CaCl2 eliminated the requirement for extended postmortem storage, as indicated by d 1 WBS. During the 14-d aging period, WBS of noninjected cuts decreased by 2.59 kg, whereas WBS of CaCl2-injected samples decreased by only .35 kg. Compared with control cuts, CaCl2 injection improved (P less than .05) d-14 WBS of steaks from SL, TS, and TR by 41.1, 40.1, and 15.3%, respectively. Additionally, CaCl2-injected subprimals exhibited higher (P less than .05) sensory panel tenderness ratings, lower (P less than .05) amounts of detectable connective tissue, and shorter (P less than .05) sarcomere lengths. No differences (P greater than .05) were observed in any quantitative collagen traits between CaCl2-injected and control cuts. These results indicate that CaCl2 injection improved ultimate tenderness and sensory ratings of meat from mature cow cuts.

Age Factors↗
PubMed1991

National beef tenderness survey.

To determine the average tenderness and sensory ratings of beef subprimal cuts sold in retail cases across the United States, retail cuts were purchased through typical retail outlets in 14 metropolitan cities and transported to Texas A&M University for sensory and Warner-Bratzler shear analysis. The overall mean shear force for all cuts was 3.65 kg, and the mean shear force values for chuck, rib, loin, and round cuts were 3.72, 3.36, 3.17, and 4.31 kg, respectively. No difference (P greater than .05) in tenderness was detected among the cuts from the rib. Mean palatability ratings and shear force values of top loin steaks were similar to those of rib cuts. Top sirloin steaks were tougher (P less than .05) and received the lowest sensory ratings compared with other loin cuts. Approximately two to three times as many round and chuck steaks had shear force values in excess of 4.6 kg compared with their roast counterparts. In all cases, roasts tended to be more tender than steaks from the same subprimal source. USDA Choice chuck retail cuts, compared to Select and No-roll chuck cuts, had approximately 10% fewer cuts with shear force values in excess of 4.0 kg. More work is needed to improve meat tenderness, primarily for retail cuts from the round and chuck primals. Future research must investigate the interaction of antemortem and postmortem factors associated with variation in beef tenderness.

Animals↗
PubMed1990

Circulating and secretory antibodies to specific food proteins in adults.

Indirect enzyme-linked immunosorbent assays (ELISA) for the detection of antibodies to gliadin, beta-lactoglobulin and ovalbumin have been developed. Specific antibody immunoglobulin levels were quantified. Serum and saliva samples were collected from twenty normal subjects and measured for the presence of specific antibodies. For each subject food intake was calculated from a 7-d weighed food inventory record. The total IgG level was 14.2 +/- 4.3 mg/ml (mean +/- s.d.). Levels of beta-lactoglobulin IgG were significantly lower than ovalbumin IgG levels (130 +/- 130 micrograms/ml versus 637 +/- 703 micrograms/ml, P less than 0.01). Gliadin IgG levels were also significantly lower than ovalbumin IgG levels (262 +/- 398 micrograms/ml versus 637 +/- 703 micrograms/ml, P less than 0.05). However, no significant difference was observed between gliadin and ovalbumin IgA levels in the subjects (29 +/- 39 per cent versus 56 +/- 122 per cent). A significant correlation was observed between ovalbumin IgG levels in serum and dietary intake of egg protein (r = 0.46, P less than 0.05). No other significant correlations were observed.

Adult↗
PubMed1989

Early parenteral feeding of amino acids.

Serial 24 hour balance studies of nitrogen and energy were carried out over 10 days in two groups of ventilator dependent preterm infants, of comparable weight and gestational age. In one group (n = 10) a parenteral amino acid source (Vamin 9) was started within 24 hours of birth, and in the other group (n = 11) it was not started until 72 hours. The feeding protocol was otherwise identical. The nitrogen intake (286 compared with 21 mg/kg/day), energy intake (188 compared with 151 kJ), and nitrogen retention (120 compared with -133 mg/kg/day), were all significantly higher during the first three days of life in the group in which the amino acid solution was started early. There were no differences by 7-10 days. The early introduction of amino acids improves the early nutritional state of sick preterm infants.

Amino Acids↗
PubMed1989

Insulin-like growth factor-I in the parenterally fed low birth weight infant.

Postnatal change in insulin-like growth factor-1 (IGF-I) was studied longitudinally in 9 very low birth weight infants (less than 1,200 g, less than 30 weeks at birth) who were receiving 85% or more of their nutrient intake via the parenteral route. There was no apparent relationship between IGF-I, nitrogen intake, energy intake, or nitrogen retention. In 6/9 infants IGF-I decreased with postnatal age. A low IGF-I may reflect the poor nutritional status and growth rate commonly seen in sick preterm infants.

Energy Intake↗
PubMed1989

Muscle protein turnover and tenderness in broiler chickens fed cimaterol.

To investigate the impact of cimaterol (CIM) on muscle protein turnover, carcass and muscle composition, muscle cathepsin B + L activity and meat tenderness, 21-d-old broiler chickens (n = 88) were assigned to dietary treatments of either 0 or 1 ppm CIM. Fractional synthesis rates (FSR), fractional accretion rates (FAR), proximate composition and collagen content were determined in the breast muscle (BM); pectoralis major) and a group of leg muscles (LM; gastrocnemius and peroneous longus) from groups of six birds per treatment within each of two time periods (age = 38 or 56 d). Whole body composition, serum hydroxyproline content and BM cathepsin B + L activity also were measured. Fractional degradation rates (FDR) were calculated as the difference between FSR and FAR. Feeding CIM increased (P less than .01) whole body protein content. Weights of LM and percentage of body weight as BM and LM were increased (P less than .05) when CIM was included in the diet. Although FSR was not significantly reduced by CIM feeding it decreased (P less than .05) with increasing age. Due to decreases in FAR, FDR thereby was reduced by CIM 31.5% and 11.9% in BM and 38.2% and 37.4% in LM at 38 d and 56 d of age, respectively. Cathepsin B + L activities also were reduced 33.6% (P less than .01) and shear forces were increased by 41% (P less than .05) by CIM feeding. For chickens fed CIM, the correlation between cathepsin B + L activity and shear force was -.63 (P less than .01). Feeding CIM improved carcass leanness and muscling due to reductions in FDR and proteolytic enzyme activity. Feeding CIM also reduced meat tenderness.

Administration, Oral↗
PubMed1989

The sick very low birthweight infant fed by parenteral nutrition: studies of nitrogen and energy.

Nine ventilator-dependent intravenously-fed very low birthweight infants with a mean birthweight of 938 (range 760-1100)g and mean gestation of 27 (range 25-29) weeks were studied provided they continued to receive more than 85 per cent of their nutritional needs intravenously. Metabolic balance studies of nitrogen over 72h were undertaken between 2 and 45d postnatal age. The average number of balances performed on each infant was three. The balances were performed at a mean postconceptional age of 5, 15, 25 and 37d. The data were compared to postconceptional age-matched fetal values and to published data from well enterally-fed infants at equivalent postnatal ages and matched for postconceptional age. There was a steady increase in length, weight and head circumference throughout the study period. The mean (range) nitrogen retention was 340 (229-415) mg/kg/d and was similar to intrauterine accretion after 200d postconceptional age, and comparable to nitrogen retention rates seen in well and enterally-fed premature infants. We conclude that parenteral nutrition can sustain growth and support nitrogen retention in the small preterm infant requiring intensive care.

Anthropometry↗
PubMed1986

Influence of propranolol on the acute thermic effect of feeding in man.

The influence of a beta-adrenergic blocker on the thermic effect of feeding (TEF) a meal was investigated in 7 healthy male volunteers. Metabolic rate (MR) was measured before and for 180 min after the consumption of 2.0 MJ 'Ensure' (Abbott Laboratories, Queensborough, Kent, UK); there were 14, 33 and 53% of energy from protein, fat and carbohydrate, respectively. On one occasion propranolol (ICI plc, Macclesfield, Ches., UK) was administered intravenously at 0.1 mg/kg body weight at meal feeding. On the second occasion a similar volume of saline was infused. Serial blood samples (10 ml) were collected before and at 30-min intervals for 180 min after meal feeding. Mean (+/- SD) resting MR was 104 (13) and 116 (11) kJ/kg and MR increased by 12.8% and 10.8% after the test meal with and without propranolol, respectively. These differences were not significant. The postprandial changes in serum glucose and triiodothyronine were similar in the two trials. The magnitude of the rise of serum insulin was similar in the two trials, but the pattern was not. beta-Adrenergenic blockade resulted in an early peak in insulin output at 30 min compared with 60 min for the control trial. We conclude that propranolol had no influence on TEF in this study.

Adult↗
PubMed1986

Use of non-absorbable markers in studies of human nutrient absorption.

Neutron activation analysis signifies a new era in the methodology of studies on nutrient utilization in humans. Yet the classical metabolic balance technique incorporating inert, non-absorbable markers will continue to be an invaluable tool for such studies. This review describes the use and abuse of a number of 'classical' inert markers, and describes the potential use of radioactive and naturally-occurring isotopes, and of heavy metals. The paucity of data critically appraising markers in infant balance trials is apparent. The comparative merits of conventional markers--carmine, polyethylene glycol 4000, chromium oxide--should be assessed. Indeed, it might be argued that the advancing knowledge on the use of naturally occurring isotopes in adults should make similar studies on infants a priority.

Absorption↗
PubMed1984

Association of hydrogen metabolism with unitrophic or mixotrophic growth of Methanosarcina barkeri on carbon monoxide.

Methanosarcina barkeri was adapted to grow on carbon monoxide by sequential transfer of the culture in medium that contained CO (100% of culture headspace). These experiments document the ability of the organism to grow slowly (65-h doubling time) and to produce methane and CO2 either on CO as the sole carbon and energy source or by the simultaneous consumption of methanol and CO. During growth on CO as carbon and energy source, net hydrogen formation occurred when the CO partial pressure in the culture headspace was greater than 20% CO, but hydrogen was consumed when the CO concentration was below this value.

Carbon Monoxide↗
PubMed1984

Weight-reducing diets, the thermic effect of feeding and energy balance in young women.

Six healthy women participated in a longitudinal study. In session one baseline data collection was made: (1) a record of customary food intake by the weighed inventory method; (2) the measurement of resting metabolic rate (RMR) and the thermic effect of feeding (TEF) a meal (2.09 MJ Ensure) together with the collection of blood samples; (3) the measurement of weight, height and assessment of body composition. On three subsequent occasions similar data were collected following periods of energy intake restriction, or free diet. Group mean (range) energy intake for session one (7 days) was 8.97 MJ (6.93-12.24); for session two (14 days) was 4.06 MJ (3.61-4.66); for session three (4 days) 1.75 MJ (1.15-2.20). No record was made for session four (free diet for 21 days). Subjects were 98-118 percent of ideal body weight at the study onset. All lost weight in sessions two and three, mean (range) 2.4 kg (1.0-3.7) and 1.4 kg (0.7-2.6) respectively. A mean of 2.2 kg (1.3-2.7) was gained in session four. Mean RMR was 122 kJ per 30 min in session one and fell by 12 percent of the mean baseline value in session two. Thereafter values returned to basal levels. TEF in session one increased mean (range) 30 percent (13-45) over RMR. There were no changes in session two. In session three TEF was 17 percent (10-28) and similar results were recorded in session four. The study suggests that TEF can be sensitive to alterations in energy intake and that this adaptive mechanism is highly variable among individuals. This has implications for the prediction of changes in body weight in response to varying levels of food intake.

Adult↗