Possible intervention of insulin, cyclic AMP, and glucocorticoids in protein-sparing action of dietary carbohydrate in rats

Real-World Diagnostic Accuracy of the On-Site Cytopathology Advance Report (OSCAR) Procedure Performed in a Multidisciplinary One-Stop Breast Clinic

Fine-needle aspiration (FNA) cytology has been widely used for the diagnosis of breast cancer lesions with the objective of differentiating benign from malignant masses. However, the occurrence of unsatisfactory samples and false-negative rates remains a matter of concern. Major improvements have been made thanks to the implementation of rapid on-site evaluation (ROSE) in multidisciplinary and integrated medical settings such as one-stop clinics (OSCs). In these settings, clinical and radiological examinations are combined with a morphological study performed by interventional pathologists. The aim of our study was to assess the diagnostic accuracy of the on-site cytopathology advance report (OSCAR) procedure on breast FNA cytologic samples in our breast OSC during the first three years (April 2004 till March 2007) of its implementation. To this goal, we retrospectively analyzed a series of 1820 breast masses (1740 patients) radiologically classified according to the American College of Radiology (ACR) BI-RADS lexicon (67.6% being either BI-RADS 4 or 5), sampled by FNA and immediately diagnosed by cytomorphology. The clinicoradiological, cytomorphological, and histological characteristics of all consecutive patients were retrieved from the hospital computerized medical records prospectively registered in the central information system. Histopathological analysis and ultrasound (US) follow-up (FU) were the reference diagnostic tests of the study design. In brief, we carried out either a histopathological verification or an 18-month US evaluation when a benign cytology was concordant with the components of the triple test. Overall, histology was available for 1138 masses, whereas 491 masses were analyzed at the 18-month US-FU. FNA specimens were morphologically nondiagnostic in 3.1%, false negatives were observed in 1.5%, and there was only one false positive (0.06%). The breast cancer prevalence was 62%. Diagnostic accuracy measures of the OSCAR procedure with their 95% confidence intervals (95% CI) were the following: sensitivity (Se) = 97.4% (96.19-98.31); specificity (Sp) = 94.98% (92.94-96.56); positive predictive value (PPV) = 96.80% (95.48-97.81); negative predictive value (NPV) = 95.91% (94.02-97.33); positive likelihood ratio (LR+) = 19.39 (13.75-27.32); negative predictive ratio (LR-) = 0.03 (0.02-0.04), and; accuracy = 96.45% (95.42-97.31). The respective positive likelihood ratio (LR+) for each of the four categories of cytopathological diagnoses (with their 95% CI) which are malignant, suspicious, benign, and nondiagnostic were 540 (76-3827); 2.69 (1.8-3.96); 0.03 (0.02-0.04); and 0.37 (0.2-0.66), respectively. In conclusion, our study demonstrates that the OSCAR procedure is a highly reliable diagnostic approach and a perfect test to select patients requiring core-needle biopsy (CNB) when performed by interventional cytopathologists in a multidisciplinary and integrated OSC setting. Besides drastically limiting the rate of nondiagnostic specimens and diagnostic turn-around time, OSCAR is an efficient and powerful first-line diagnostic approach for patient-centered care.

Lack of toxicity by medium chain triglycerides (MCT) in canines during a 90-day feeding study

Dietary fats in food are natural energy sources to animals and are included in the American Association of Feed Control Officials (AAFCO) manual as a requirement for dog food. Medium chain triglycerides are comprised of a glycerol backbone esterified to medium chain length (8-12 carbon) fatty acids (FA) and, in the context of this report, are all saturated FA. Unlike esterified long chain (>12 carbons) FA (long chain triglycerides or LCT), MCT are lower in caloric value, and are eliminated from the body more quickly than LCT. The objective of this study was to determine the safety of MCT when fed to beagles for 90 days at levels of 0%, 5%, 10%, and 15% MCT added to conventional feed. The beagles were monitored for signs of toxicity by clinical observations, body weight measurements, food consumption level, physical examinations, hematology and serum chemistry, ophthalmic examinations, and urinalysis. There were no signs of toxic effects observed in any of the animals that were related to feed, and the animal viability was 100% at the end of the study. Some animals exhibited significant increased blood urea nitrogen, potassium and cholesterol levels in the 10% and 15% MCT-fed groups. Also, in the same groups with elevated nitrogen, there were concomitant reductions in total blood protein and urine volumes. These changes in serum chemistry may be the result of protein sparing effects due to the high levels of MCT intake, and are not deemed to be pathological in nature. Animals receiving 15% MCT in feed had lower levels of food intake due to palatability issues. From the other examination parameters, there were no significant changes noted between groups receiving MCT and vehicle feed. No safety concerns were noted at any dose level, although an issue with palatability precluded identifying 15% as the highest dose level tested.

Urea synthesis and leucine turnover in growing pigs: changes during 2 d following the addition of carbohydrate or fat to the diet

1. Studies have been made of the time-sequence of protein metabolic and hormonal changes following an abrupt increase in carbohydrate or fat intake. [3H]leucine and [14C]urea were infused for 72 h, via the aorta, into fourteen female pigs (30-38 kg body-weight). At 24 h after the start of the infusion their feed was either changed to one of two isonitrogenous diets containing additional starch (group BS, five animals) or fat (group BF, five animals), or remained unaltered (group BB, four animals). The distribution space of urea was measured by the dilution of a single dose of [14C]urea given both 48 h before and 48 h after the change in diet. The changes in the concentration and specific radioactivity of blood leucine were used to infer changes in protein turnover and those of plasma urea to measure total amino acid catabolism. The concentrations of blood glucose and plasma insulin and cortisol were also measured at approximately two-hourly intervals for the 48 h period following the change in diet. 2. Within 4 h of either change in diet blood leucine concentration was lowered and the leucine specific radioactivity was raised above that in group BB, but after 24 h both the concentration and specific radioactivity of leucine returned to values similar to those in group BB. Eventually the blood leucine specific radioactivity was slightly but not significantly reduced below that of group BB. 3. The addition of starch to the diet significantly reduced the synthesis and concentration of urea within 4 h but, although the addition of fat to the diet eventually lowered the urea concentration and synthesis, both changes were delayed for 18-24 h. 4. In group BS plasma glucose and insulin rose after the addition of starch, but after 24-36 h both returned to values that were the same as those in the animals that received the same diet throughout (group BB). The addition of fat to the diet altered neither blood glucose nor plasma insulin concentrations. The addition of either carbohydrate or fat to the diet eventually reduced plasma cortisol concentrations, but the change did not occur until 24 h after the change in diet. 5. The results suggest that alterations in non-protein energy supply exert their immediate effect on the degradation of whole-body protein. They do not exclude the possibility that these early changes may reflect opposing changes at different sites.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of changes in the intakes of protein and non-protein energy on whole-body protein turnover in growing pigs

1. The relationships between the intakes of protein and of non-protein energy (NPE), nitrogcn retention and body protein synthesis have been studied in female pigs weighing 30 and 35 kg.

2. Four animals were assigned to three regimens and given a conventional (basal) diet supplemented with fat, carbohydrate or protein. After 1 week, measurements of N excretion in urine and faeces (7 d collection) and gaseous exchange (3–4 d) were made. At the end of the balance period a solution of [l-14C]leucine was infused at a constant rate. Body protein synthesis was then calculated as the difference between the apparent irreversible loss of blood leucine and the loss of 14C in expired air.

The animals were then offered the basal diet without supplement for 10 d and the measurements of N retention, energy retention and protein synthesis were repeated.

3. The intakes of metabolizable energy (ME; MJ/kg body-weight (W)0.75per d) were 1.75 for fat, 1.58 for carbohydrate, 1–25for protein and 1.18 for the basal diet; corresponding intakes of apparently digestible N (ADN; g N/kgW0.75 per d) were 2.30,2.31,4.35 and 2–17. Daily N retention, which during the period of basal feeding was 13.6 g was increased by between 3.4 and 7.2 g by the supplements. Daily fat deposition was also increased in the animals that received the diets supplemented with carbohydrate and fat.

4. The rate of leucine catabolism was significantly reduced in the animals receiving the diets that were supplemented with W Eand increased by the addition of protein to the diet.

5. When based on the specfic radioactivity of blood leucine both the synthesis and breakdown of body protein (per unit metabolic body-weight) were increased by 30% in the animals receiving the high-protein diet but the increases in protein synthesis associated with the addition of carbohydrate (+14%) and fat (+12%) were much less marked. Consideration of these results together with previous observations (Reeds et al. 1980) suggested that body protein synthesis(g N/d) increased by 0.88 for each g increase in daily ADN and by 0.93 for each MJ increase in daily ME intake.

6. Comparison of the results obtained with the animals given high-carbohydrate diets and those given high-protein diets suggested an increase in heat production of 14 KJ/g of additional fat deposition. A similar comparison of animals receiving the high-protein and basal diets suggested a heat increment of 23.5KJ/g additional protein deposition. The changes in heat production and protein synthesis in the animals given the protein supplement were compatible with a heat increment of 5.3 KJ/g additional protein synthesized. Because of the large proportion of heat production associated with the deposition of fat this could not be confirmed with either of the other supplements, but it is possible that the energy cost of protein accretion varies with the relative proportions of protein and NPE in the diet.

The protein-sparing effect of carbohydrate. 2. The role of insulin

1. In five experiments with growing female pigs of 38-63 kg, insulin (2 mU/kg) per min) and glucose (9-17 mg/kg per min) were infused continuously for 3-7 d. In three further experiments, glucose (9 mg/kg per min) was infused alone for 5 d. 2. In response to the combined infusion, plasma insulin increased 2-7-fold, plasma glucose decreased, on average, by 50% and plasma urea concentration was reduced by 40%. Urinary excretion of urea and nitrogen decreased after the first day of infusion to values averaging 70% of control levels. 3. The infusion of glucose alone provoked only a small increase in plasma insulin. The reduction of urinary urea and of N excretion were approximately 25% of those observed with the combined infusions.

The problem of human protein requirements: some kinetic and metabolic considerations

Estimated human protein requirements have been substantially lowered by FAO/WHO expert committees over the past two decades. The estimates and methods of calculation are considered in the light of the kinetics of response to protein intake, body protein turnover, amino acid flows in the body, and the concept of nitrogen (N) steady state. Whereas traditional methods of estimation have assumed an essentially linear (first order) response of N retention to absorbed N, animal studies show that response to graded protein intakes obeys saturation kinetics. Corrections for protein quality have also assumed a linear relation between response and supply of limiting amino acid, while animal experiments indicate that this response likewise follows saturation kinetics. Evidence is lacking that the present minimum protein standards for humans can support acceptable internal nitrogen steady states at any age above infancy or foster normal growth in the child. New research approaches to determination of protein requirements are suggested , including study of the kinetics of human response to graded protein intakes and graded variations of quality; development of indicators of nitrogen steady state and correlation with clinical status; and determination of optimum protein-energy ratios by age and sex.