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Biomedical subjects

M Macari

Publications and source records attributed to M Macari.

52 records · Page 3Linked to original sources
PubMed1985

Effects of acute heat exposure on respiratory metabolism and blood glucose in freshwater fishes, Prochilodus scrofa (curimbatá) and Cyprinus carpio (carp) acclimatized to tropical winter.

Routine oxygen consumption and blood glucose were determined from freshwater fishes, Prochilodus scrofa and Cyprinus carpio, exposed at high temperatures for 1 hr. Prochilodus scrofa had a significantly higher rate of oxygen consumption at 30 degrees C than at 25 degrees C, and carp higher at 25 degrees C than at 30 degrees C. Blood glucose was significantly higher for Cyprinus carpio than for Prochilodus scrofa at 25 and 30 degrees C; however, after exposure to these temperatures for 1 hr blood glucose did not change significantly for both species. The results suggest that these interspecific variations may be linked to the differences between native and foreign fishes and their way of life.

Animals↗
PubMed1985

Observations on the development of the febrile response to pyrogen in newborn pigs.

The febrile response of newborn pigs to exogenous pyrogen injection was investigated. Lipopolysaccharides (LPS, E. coli) were injected intravenously into the superior vena cava of 1-30-day-old piglets. All the experiments were carried out in littermates half of which were injected with pyrogen and half with pyrogen-free saline. Newborn pigs did not develop a febrile response from 1 to 4 days of age; however, when the animals were 5 days old exogenous pyrogen determined a typical monophasic febrile response. A second intravenous injection of pyrogen into newborn pigs (1 day old) 24 h after the first did not raise body temperature. It is suggested that newborn pigs behave like the newborn of other mammalian species regarding endotoxin-induced thermogenesis.

Aging↗
PubMed1984

Food intake and thermic effect of feeding in thyroid-deficient pigs.

Short and long-term thyroidectomy and Methimazole treatment reduced food intake in young growing pigs. The thermic effect of feeding assessed by the increment in rectal temperature after the beginning of food ingestion was reduced in thyroidectomized animals, but no effect could be observed in Methimazole-treated pigs. Propranolol injection after short-term treatment decreased food intake in sham-operated and treated animals, but reduced the thermic effect of feeding only in thyroidectomized and Methimazole-treated pigs. Long-term treatment inhibited the effect of propranolol in reducing food intake and the thermic effect of feeding. On the basis of these data, it was suggested that the interaction between thyroid hormones and catecholamines (noradrenaline) plays an important role in the regulation of food intake and in the thermic effect of feeding in thyroid-deficient pigs.

Animals↗
PubMed1983

Changes in food intake in response to alterations in the ambient temperature: modifications by previous thermal and nutritional experience.

1. The influence of ambient temperature on ad libitum food intake has been investigated in piglets weaned at 2 weeks and kept in the hot (35 degrees C) or the cold (10 degrees C) on a high or low energy intake for 6 weeks. Further, the extent to which food intake was correlated with fasting body temperatures and resting metabolic rate was also examined. 2. The amount of food eaten in a single meal was recorded daily in two series of tests. In Test I, measurements were made both at the normal living temperature and after 2 and 24 h at thermal neutrality (25 degrees C). In Test II, the animals were examined at 25 degrees C over a 4 day period. Resting metabolic rate and body temperatures were also measured, immediately before the measurement of food intake. 3. Food intake was much greater at 10 than at 35 degrees C, but even at thermal neutrality it was significantly higher for those which had been in the cold. This was true for periods of between 2h and 4 days at 25 degrees C. Although food intake was not correlated with skin or core temperatures, there was an indication of a correlation with metabolic rate, particularly at thermal neutrality. 4. The results show that long-term cold exposure has a lasting effect on food intake, even at thermal neutrality, and it is suggested that this may be related to hormonal changes.

Acclimatization↗
PubMed1983

Influence of thermal and nutritional acclimatization on body temperatures and metabolic rate.

1. An investigation of the influence of previous thermal and nutritional experience on body temperatures and metabolic rate has been carried out with growing piglets. Littermates were kept, from shortly after birth, at either 10 or 35 degrees C and fed either a high (H) or a low (L) energy intake. At 8 weeks of age the animals were exposed to a series of environmental temperatures of 10, 20, 27 and 35 degrees C for 1.5 hr and their rates of oxygen consumption were determined over the last 45 min. At the end of the session body temperatures were measured. 2. Rectal temperatures measured 24 hr after the start of the last meal were higher at each test temperature in piglets which had been living at 35 degrees C than in those at 10 degrees C. Also, rectal temperatures were higher in those on the H intake for animals which had been living in either the hot or the cold environment. 3. Skin temperature on the back was similar in all groups at any given test temperature although there was a tendency for those on an H intake to have the higher temperatures. Skin temperatures of the legs and ears were higher in the 10H and 10L groups than in the 35H or 35L groups at all the test environmental temperatures; energy intake had little effect. 4. Metabolic rate was greater for the animals on the H than the L intake, for those which had been living at either 10 or 35 degrees C at all the test environmental temperatures. The analysis did not reveal any significant difference related to the overall effect of living temperature, which was independent of energy intake. 5. At thermal neutrality (27 degrees C) there was a significant interaction, between energy intake and normal living temperature, on metabolic rate. Living temperature was found to modify the effect of intake: the difference between the two intakes was greater in those from the cold environment than from the hot.

Acclimatization↗
PubMed1983

Effects of fasting, noradrenaline and glucose tolerance test on free fatty acids and blood glucose in thyroid-deficient pigs.

1. This experiment was carried out to study the effects of thyroidectomy or treatment with an anti-thyroid drug (Methimazole) on the lipolytic and glycogenolytic responses to fasting, noradrenaline and glucose tolerance test in young growing pigs. 2. Male and female crossbred pigs weighing 15-30 kg were used. 3. Fasting caused a slight hypoglycemic response but without statistical differences between euthyroid and thyroid-deficient animals. 4. Free-fatty acids mobilization was significantly different between euthyroid and thyroid-deficient pigs and, the lipolytic effect of NA was lower in thyroidectomized animals than in treated or euthyroid pigs. 5. Glucose tolerance test was not different among the groups. However, FFA mobilization during the GTT was significantly different. 6. The results suggest that the interaction between catecholamines-thyroid hormones play an important role in the FFA mobilization in vivo.

Animals↗
PubMed1983

Increase in plasma concentrations of 3,5,3'-triiodothyronine and thyroxine after a meal, and its dependence on energy intake.

Plasma concentrations of 3,5,3'-triiodothyronine (T3) and thyroxine (T4) were measured before, during and for between 2 and 6 hr following a meal, in young growing piglets. T3 increased after a meal and reached a peak at approximately 60 min. The magnitude of the rise was dependent on both the energy content and nutrient composition of the meal. In animals given either a high or low energy intake baseline values of T3 were similar, whereas there was a difference in the response to a meal (P less than 0.01). Average increases in hormone concentration were 120% (P less than 0.001) and 50% (P less than 0.05) on the high and low intakes respectively. Plasma T4 also increased in those on high intake (P less than 0.025), but no change was detected when the intake was low. The response of T3 to a meal high in either glucose, sucrose, fat or protein was statistically significant except for the protein meal. The rise in T4 after each of these four meals was less consistent, although it did increase significantly after meals high in sucrose or fat. Amongst several possibilities, these results suggest that a meal may induce an increase in secretion of T3 and T4 from the thyroid gland.

Animals↗
PubMed1983

Thyroid hormone metabolism after acclimatization to warm or cold temperature under conditions of high or low energy intake.

The separate effects of ambient temperature and energy intake on the metabolism of thyroid hormones in the young pig have been investigated. Piglets were kept singly from 4 weeks of age at 10 or 35 degrees C on a high (H), or low (L) energy intake, such that H = 2L. At the tenth week of age blood samples were taken 16-21 h after the last meal for the determination of plasma concentrations of thyroxine (T4) and 3,5,3'-triiodothyronine (T3). At the end of the tenth week of age the fractional disappearance rate (K) of T4 was determined and finally the K value for T3 was estimated. Plasma concentrations of T4 and T3 were greater in animals on a high intake than in those on a low intake, (P less than 0.02), but the temperature at which the animals lived had no significant effect. The values of K for T4 and T3 were greater at 10 than at 35 degrees C (P less than 0.010 and P less than 0.05), and energy intake had no significant effect. Calculations of the catabolic rates in nmol/kg X h revealed that for T4 the rate was greater at 10 than at 35 degrees C (P less than 0.001) and on a high than on a low intake (P less than 0.01). Similar differences were found between the mean values of T3 with respect to both temperature and energy intake, but the variance was large and they did not reach statistical significance. It is concluded that the metabolism of thyroid hormones is influenced independently by both ambient temperature and energy intake.

Acclimatization↗
PubMed1978

Sexual maturity in rabbits defined by the physical and chemical characteristics of the semen.

Semen was collected weekly from New Zealand white rabbits from the 1st positive mounting test to 43 weeks of age by means of an artificial vagina. The mean values of the results obtained in the 1st and 20th collection weeks were respectively: volume (ml) 0.61 +/- 0.30 and 0.70 +/- 0.19; pH 7.22 +/- 0.50 and 7.19 +/- 0.15; concentration (sperm/mm3 X 10(3)) 750 +/- 207 and 381 +/- 90; fructose (mg/100 ml) 117 +/- 58 and 203 +/- 121; citric acid (mg/100 ml) 256 +/- 90 and 200 +/- 97; sodium ions (mEq/l) 133 +/- 31 and 163 +/- 46; potassium ions (mEq/l) 40 +/- 21 and 29 +/- 14. On the basis of these results, New Zealand white rabbits reach sexual maturity by 6 months of age.

Animals↗
PubMedDate not supplied

Cystic pancreatic masses: cross-sectional imaging observations and serial follow-up.

BACKGROUND: We retrospectively reviewed the imaging features of a series of patients with cystic pancreatic masses, the majority of whom underwent imaging surveillance. METHODS: Imaging data from 30 patients with known cystic pancreatic masses were reviewed. Nine patients had surgical and/or cytologic classification. Of the 21 who were not operated on, all underwent serial imaging surveillance. Of these, five had corroborative endoscopic retrograde cholangiopancreatography and 16 were followed by only computed tomography and/or magnetic resonance imaging. RESULTS: In the nonoperated group, mean follow-up time was 30 months (3-144 months). Two patients demonstrated growth, and the remainder remain stable. In the patients who underwent surgery, invasive carcinoma was found in those with lesions larger than 4 cm, involvement of the main pancreatic duct, or visible solid components on the imaging study. Smaller lesions were benign. CONCLUSION: In patients with suspected cystic pancreatic neoplasms, surveillance might be possible if lesions are smaller than 2.5 cm, spare the main pancreatic duct, and demonstrate no solid components.

Adenocarcinoma↗
PubMedDate not supplied

CT demonstration of infected SVC thrombus.

We report a case in which computed tomography (CT) demonstrated gas within a thrombus in the superior vena cava in a patient with fever of unknown origin (FUO), indicating that the thrombus was infected. This CT finding is important to recognize, as it affects subsequent therapy.

Humans↗
PubMedDate not supplied

CT diagnosis of ileal diverticulitis.

The preoperative diagnosis of ileal diverticulitis has been reported during small-bowel series when inflammatory changes are associated with ileal diverticula. Previous CT reports of this entity have failed to establish the specific diagnosis preoperatively. We report the CT findings in a patient with right lower quadrant pain that enabled the specific diagnosis of ileal diverticulitis to be made.

Diverticulitis↗