Newcastle disease virus fusion and haemagglutinin-neuraminidase gene motifs as markers for viral lineage.

Reverse transcriptase polymerase chain reaction was used to generate sequence data for 91 Australian Newcastle disease viruses (NDV) isolated from 1932 to 2000 covering the cleavage site of the fusion (F) protein and the C-terminus of the haemagglutinin-neuraminidase (HN) protein. Comparison of sequences at these two sites indicates distinct evolutionary relationships between these viruses. Typically, HN gene relationships revealed by phylogenetic analyses were also maintained in comparisons between F gene cleavage sites; however, the former analyses appeared to give a clearer indication of the lineage of a virus isolate. This data supports and extends earlier observations in that there is no evidence for gene exchange by recombination but that different strains appear to have evolved through synonymous mutations. Inter-relationships, especially between Australian NDV isolates, appear to be associated with lineages having the same C-terminal HN extensions rather than associated with virulence of the virus. A proposed mechanism for this observation is discussed.

Urinary vascular endothelial growth factor concentrations in women undergoing gonadotrophin treatment.

A recently identified cytokine, vascular endothelial growth factor (VEGF, vascular permeability factor) has been implicated in ovarian hyperstimulation syndrome in women undergoing assisted reproduction. We postulate that circulating and urinary VEGF values increase following gonadotrophin stimulation, in parallel with the increased ovarian vascularity. A VEGF radioimmunoassay was developed using iodinated VEGF as tracer, a goat anti-VEGF serum as antiserum and recombinant human VEGF as standard. The specificity of the assay was confirmed by comparing the reverse phase high-performance liquid chromatography (HPLC) pattern of VEGF immunoactivity in urine and urine spiked with recombinant VEGF. Urine was concentrated 5-fold prior to measurement by the radioimmunoassay. VEGF:creatinine ratios in early morning urine samples were used to monitor daily urinary VEGF concentrations based on its high correlation (r = 0.77, P < 0.001) with VEGF concentrations in 24 h urine collections. No diurnal variation in VEGF:creatinine ratios was detected. VEGF:creatinine ratios were determined daily from nine women undergoing gonadotrophin-releasing hormone (GnRH) agonist/gonadotrophin treatment. In a further 16 women, early morning urine samples were collected in the peri-ovulatory period. A significant increase (P < 0.005, n = 25) was observed in VEGF:creatinine ratios following human chorionic gonadotrophin (HCG) administration. VEGF:creatinine ratios correlated poorly (r < 0.34) with plasma oestradiol, follicle number and size. It is concluded that urinary VEGF/creatinine ratios increase following HCG stimulation.

Effect of low and high amounts of a structured lipid containing fish oil on protein metabolism in enterally fed burned rats.

To determine the optimal fat intake and source in nutritional support, we measured the protein-sparing effects of a structured lipid (SL) derived from 60% medium-chain triglyceride (MCT) and 40% fish oil and a 50:50 soybean to safflower oil emulsion (long-chain triglyceride, LCT). Male Sprague-Dawley rats received an enteral diet for 7 d with either all nonprotein energy as dextrose (control diet) or 10% or 35% nonprotein energy as SL or LCT. The rats were burned on day 3. Indirect calorimetry and nitrogen balance were measured on day 2 (preburn) and days 4 and 6 (postburn). Respiratory quotient decreased postburn. There was a significant increase in total energy expenditure postburn, particularly with 35% LCT. Nitrogen balance was best without fat and 10% fat compared with 35% fat and with SL compared with LCT. These results confirm previous studies that fish oil-containing SLs possess protein-sparing effects in burn injury and that 10% SL seems optimal for nutritional support in burn injury.

Effect of treatment of dairy cows with slow-release bovine somatotropin during the periparturient period on minerals in plasma and milk and on parathyroid hormone-related protein in milk.

Slow-release bST was given to dairy cows as a single injection prior to calving to determine whether such treatment prevented parturient hypocalcemia or modified the concentrations of Ca and parathyroid hormone-related protein in milk during the periparturient period. Cows were treated about 1 wk prepartum, and serial blood and milk samples were taken from these and similar prepartum control cows over a 3-wk period. Plasma growth hormone concentrations in the bST-treated group reached a peak 2 d after administration and then declined linearly to control concentrations over a 14-d period. Plasma Ca was unaffected by bST treatment 1 d prior to parturition, on the day of parturition, and at 1 and 6 to 9 d postpartum. Plasma P was higher, and plasma Mg was lower, in the bST-treated group on the day of parturition and 1 d postpartum. Concentrations of Ca, P, Mg, and protein in milk were lower in bST-treated cows than in controls at parturition. Milk production of the bST-treated and control groups was similar when measured at d 6 to 9 postpartum. Concentrations of parathyroid hormone-related protein in milk were substantial at parturition and remained high thereafter, although at parturition the concentration in the milk of the bST-treated group was lower than that of the control group.

Long-term feeding with structured lipid composed of medium-chain and N-3 fatty acids ameliorates endotoxic shock in guinea pigs.

The metabolic and physiologic responses to 7-hour endotoxin infusion (5.0 mg/kg h) were evaluated in guinea pigs following 6 weeks of dietary enrichment with diets containing either chemically structured lipid (SL) composed of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT) in the form of N-3 polyunsaturated fatty acids (PUFAs), or safflower oil (SO), which is high in N-6 fatty acids. Plasma phospholipid fatty acid profiles, arterial blood pH, PCO2, PO2, HCO3, lactate, blood pressure, oxygen consumption, and energy expenditure were examined. Plasma phospholipid fatty acids profiles reflected dietary intake with SL-fed animals demonstrating a significantly higher N-3 to N-6 fatty acid ratio compared with SO-fed animals. SL-fed animals responded to endotoxemia with a mild metabolic acidosis with respiratory compensation, which was associated with moderate lactatemia (3 mmol/L). SO-fed animals developed a severe metabolic acidosis with acidemia and respiratory compensation, which was associated with hyperlactatemia (8 mmol/L, P less than .05 v SL). No differences were observed in blood pressure, oxygen consumption, energy expenditure, or respiratory quotient during endotoxemia between dietary groups compared with controls. We conclude that diets enriched with structured lipid composed of medium-chain and N-3 fatty acids can attenuate the sequelae of endotoxemia.

Persistence of metabolic effects after long-term oral feeding of a structured triglyceride derived from medium-chain triglyceride and fish oil in burned and normal rats.

The persistence of metabolic effects following long-term oral feeding of a structured triglyceride rich in omega-3 fatty acids was studied in burned and normal rats, and compared with controls fed safflower oil, a long-chain triglyceride high in omega-6 fatty acid content. Male Sprague-Dawley rats were pair-fed a high fat diet as either structured triglyceride or safflower oil for 42 days. On day 43, a jugular catheter was placed, and rats received either a dorsal surface scald or sham injury. Following a 48-hour fast, body weight, nitrogen loss, energy metabolism, and liver weight were measured, and whole-body and tissue-specific protein kinetics were studied by constant intravenous infusion of [1-14C]leucine. Plasma albumin, free fatty acids, glucose, insulin, and triglyceride fatty acid composition were determined. Urinary nitrogen loss, energy expenditure, and plasma leucine concentration were elevated in burned rats, confirming the presence of an injury response. Rats previously fed structured triglyceride had greater liver weight, total liver protein, and percentage of leucine flux oxidized, and plasma levels of glucose and insulin were increased. Plasma leucine concentration was decreased in rats previously fed structured triglyceride. Plasma triglyceride and phospholipid fatty acid analysis showed a reduction in arachidonic acid and an increase in omega-3 fatty acids in rats previously fed structured triglyceride. Long-term feeding of structured triglyceride induced major systemic metabolic changes related to the dietary fatty acid composition that persist after the diet is discontinued.

Parenteral infusion of long- and medium-chain triglycerides and reticuloendothelial system function in man.

Previous study demonstrated that patients who received total parenteral nutrition (TPN) with standard intermittent infusion of long chain triglyceride (LCT) at 0.13 g kg-1hr-1 over 10 hr for each of three days showed a significant decline in 99Tc-sulfur colloid (TSC) clearance rate by the reticuloendothelial system (RES). The present studies evaluated eight patients who received the same total lipid dose of LCT infused continuously as in a three-in-one admixture, and another nine patients receiving the same amount of fat as a medium chain triglyceride (MCT)/LCT (75%/25%) emulsion intermittently over 10 hr at 0.13 g kg-1hr-1 for three consecutive days. Patients were given continuous total parenteral nutrition (TPN) comprised of protein, 1.5 g kg-1day-1, and dextrose, 4.5 g kg-1day-1. RES function was examined by measuring the clearance rates of intravenously injected TSC while receiving TPN containing only protein and dextrose, and again after three days of fat infusion. Mean (+/- SEM) clearance rate constants before and after continuous LCT infusion were 0.38 +/- 0.09 and 0.41 +/- 0.08 min-1, respectively, while those before and after intermittent MCT/LCT infusion were 0.50 +/- 0.18 and 0.73 +/- 0.24 min-1, respectively. In contrast to intermittent LCT infusion, the administration of continuous LCT or an intermittent MCT/LCT mixture does not impair TSC clearance by the RES. These findings suggest that condensing the daily period of LCT infusion at standard dosage may exceed the rate of metabolic utilization, resulting in increased fat removal and diminished TSC uptake by the RES.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of long-chain triglyceride emulsions on reticuloendothelial system function in humans.

Parenteral administration of long-chain triglyceride emulsions has been shown to have deleterious effects on reticuloendothelial system function in animal models. It is unknown whether this interference occurs in humans with clinically relevant doses of intravenous fat. Two studies were done. Eighteen patients were prospectively enrolled for study. Patients received full feeding by continuous total parenteral nutrition (amino acids 1.5 g/kg/day and dextrose 4.5 g/kg/day) with 33.1 kcal/kg/day. Forty-three % of the nonprotein calories were provided as soybean oil emulsion (Travamulsion 20%) and was administered intravenously over 10 hr (0.130 g/kg/hr). Reticuloendothelial system function was determined by measuring the change in the clearance rate of intravenously injected 99mTc-sulfur colloid (TSC) in each patient. In study 1 (n = 10), one day of lipid (10 hr) was infused, with the clearance of 99mTc-sulfur colloid measured before the lipid was infused and then during the last hour of the 10-hr infusion. In study 2 (n = 8), the clearance rates were measured before the lipid emulsion was begun, and then during the last hour of the infusion on the 3rd day. Clearance rates for TSC after 10 hr of lipid infusion in study 1 did not differ (0.27 +/- 1/min to 0.26 +/- 0.1/min, p greater than 0.10). However, after 3 days of lipid infusion (10 hr/day), a statistically significant reduction in TSC was seen (0.46 +/- 0.08/min-0.27 +/- 0.03/min, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration of structured lipid composed of MCT and fish oil reduces net protein catabolism in enterally fed burned rats.

The effects of enteral feeding with safflower oil or a structured lipid (SL) derived from 60% medium-chain triglyceride (MCT) and 40% fish oil (MCT/fish oil) on protein and energy metabolism were compared in gastrostomy-fed burned rats (30% body surface area) by measuring oxygen consumption, carbon dioxide production, nitrogen balance, total liver protein, whole-body leucine kinetics, and rectus muscle and liver protein fractional synthetic rates (FSR, %/day). Male Sprague-Dawley rats (195 +/- 5g) received 50 ml/day of an enteral regimen containing 50 kcal, 2 g amino acids, and 40% nonprotein calories as lipid for three days. Protein kinetics were estimated by using a continuous L-[1-14C] leucine infusion technique on day 2. Thermally injured rats enterally fed MCT/fish oil yielded significantly higher daily and cumulative nitrogen balances (p less than or equal to 0.025) and rectus muscle (39%) FSR (p less than or equal to 0.05) when compared with safflower oil. MCT/fish oil showed a 22% decrease (p less than or equal to 0.005) in per cent flux oxidized and a 7% (p less than or equal to 0.05) decrease in total energy expenditure (TEE) versus safflower oil. A 15% increase in liver FSR was accompanied by a significant elevation (p less than or equal to 0.025) in total liver protein with MCT/fish oil. This novel SL shares the properties of other structured lipids in that it reduces the net protein catabolic effects of burn injury, in part, by influencing tissue protein synthetic rates. The reduction in TEE is unique to MCT/fish oil and may relate to the ability of fish oil to diminish the injury response.