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Biomedical subjects

A Barletta

Publications and source records attributed to A Barletta.

At least 19 recordsLinked to original sources
PubMed2004

Modulation of hepatic mitochondrial energy efficiency with age.

This study was designed to examine the effect of youth-adulthood transition on hepatic mitochondrial energy efficiency. The changes in basal and palmitate-induced proton leak, which contribute to mitochondrial efficiency, were evaluated in mitochondria isolated from the liver of young and adult rats. Alterations in mitochondrial cytochrome oxidase and aconitase specific activities, and in adenine nucleotide translocator content were also assessed. There was no difference in basal proton leak or thermodynamic coupling and efficiency of oxidative phosphorylation in liver mitochondria between the two rat groups. On the other hand, palmitate-induced proton leak increased significantly in adult rats. The function of this uncoupling could be avoidance of elevated formation of reactive oxygen species, which are known to accelerate ageing.

Aconitate Hydratase↗
PubMed2001

Fat balance and serum leptin concentrations in normal, hypothyroid, and hyperthyroid rats.

OBJECTIVE: To study the influence of thyroid hormones on the relationship between serum leptin and fat mass, as well as on energy and macronutrient balance. DESIGN: Rats with different thyroid states were obtained by 7 and 15 days of treatment with the antithyroid drug propylthiouracil or with triiodothyronine (T3). MEASUREMENTS: Energy balance, macronutrient balance and serum leptin concentrations. RESULTS: In hypothyroid rats we found a decrease in metabolizable energy (ME) intake and energy expenditure together with an increase in lipid gain/lipid intake ratio and a decrease in protein gain/protein intake ratio. Consequently, body lipid percentage significantly increased compared to euthyroid rats. Hyperthyroid rats first increased energy expenditure and later ME intake, so that increased metabolism was balanced by increased intake, and energy gain was similar to that found in euthyroid rats. CONCLUSION: These results indicate that T3 plays a major role in the maintenance of energy and lipid balance. Our results also indicate that an inverse relationship exists between T3 and leptin serum concentrations, and that this relationship is not only the result of changes in body fat stores induced by changed T3 concentrations.

Adipose Tissue↗
PubMed2001

Effect of cold exposure on energy balance and liver respiratory capacity in post-weaning rats fed a high-fat diet.

Variations in energy balance, body composition, and nutrient partitioning induced by high-fat feeding, cold exposure or by concomitant high-fat feeding and cold exposure were studied in young Wistar rats. Changes in hepatic metabolism as well as in serum free triiodothyronine and leptin levels were also evaluated. Rats were exposed to either 24 or 4 degrees C and fed either a low- or high-fat diet (10 % or 50 % energy respectively) for 2 weeks. Relative to low-fat feeding at 24 degrees C, both energy intake and expenditure were increased by high-fat feeding or by cold exposure, and these changes were accompanied by increased serum triiodothyronine levels. In response to concomitant high-fat feeding and cold exposure, serum triiodothyronine tended to be further elevated, but no further increases in energy intake or energy expenditure were observed. Independently of diet, the increased energy expenditure in cold-exposed rats was not completely balanced by adaptive hyperphagia, with consequential reductions in protein and fat gain, accompanied by marked decreases in serum leptin. Furthermore, unlike high-fat feeding at 24 degrees C, cold exposure enhanced hepatic mitochondrial oxidative capacity both in the low-fat- and high-fat-fed groups. It is concluded that in this strain of young Wistar rats, despite similarly marked stimulation of energy expenditure by high-fat feeding at 24 degrees C, by cold exposure and by concomitant high-fat feeding and cold exposure, an increased hepatic oxidative capacity occurred only in the presence of the cold stimulus.

Animals↗
PubMed2000

Effect of long-term high-fat feeding on energy balance and liver oxidative activity in rats.

The purpose of this work was to study the effect of early long-term high-fat feeding on energy balance and liver oxidative activity. To this end, rats aged about 30 d were fed a high-fat or a low-fat diet for 15, 30 or 60 d. Full energy balance and energy partitioning measurements were carried out. In addition, we measured hepatic mitochondrial and peroxisomal oxidative capacities. Serum levels of free triiodothyronine (T3) and leptin were also determined. Rats fed a high-fat diet showed an increase in metabolizable energy intake as well as in energy expenditure, while lipid gain over the whole period was lower than that expected due to a decrease in metabolic efficiency. An increase in serum free T3 levels was also found in rats fed a high-fat diet after 15 and 30 d. Statistically significant correlations between serum leptin levels and body fat mass were found after 15, 30 and 60 d of high-fat feeding. Finally, no variation in hepatic mitochondrial and peroxisomal fatty acid oxidation capacity was found in rats fed a high-fat diet for 15, 30 or 60 d. In conclusion, the results of the present study show that young Wistar rats fed a high-fat diet for up to 60 d are able to counteract, at least in part, obesity development.

Animals↗
PubMed1999

Radiation therapy alone in stage III-B cancer of the uterine cervix--a 17-year old experience in southern Brazil.

PURPOSE: External irradiation followed by intracavitary therapy (EBIC) has been considered the standard treatment for stage III-B cancer of the uterine cervix. For different reasons, some patients are not suited for intracavitary therapy (ICT), and the treatment may be given entirely by external beam irradiation alone (EBRTA). The purpose of our study is to discuss treatment results and complications for patients undergoing EBIC or EBRTA. METHODS AND MATERIALS: A retrospective study was carried out on 202 eligible patients with stage III-B cancer of the uterine cervix admitted for radiotherapy from 1980-1997. Ninety-three patients were able to receive EBIC (50 Gy, 8 MV RX whole pelvis followed by one session of 38-45 Gy ICT to point A). The remaining received EBRTA (50-70 Gy for 5-9 or more weeks). Median follow-up procedure was 18.5 months (range: 4-182) for all patients and 26 months (range 4-147) for the patients at risk. RESULTS: The most frequent reason for precluding ICT was large residual tumor volume (32.1%). Ten-year overall survival rates, relapse free survival, and pelvic failure rate for the EBIC and EBRTA patients were, respectively, 22.5% x 15.6% (p = 0.0087), 23.5% x 14.8% (p = 0.005), and 51.6% x 68.8% (p = 0.005). However, when the same comparisons were performed with EBIC patients x EBRTA patients receiving a high dose schedule (60 Gy/6-8 wk to 70 Gy/7-9 wk), the results of the EBIC group remained higher, but the differences became insignificant: respectively, 22.5% x 18.9% (p = 0.17), 23.5% x 15.3% (p = 0.052), and 51.6% x 60.0% (p = 0.10). The distribution of complications was similar in both groups. CONCLUSIONS: We found that EBIC was the best treatment modality in our patients with stage III-B cancer of the uterine cervix, whereas for patients who were not candidates for ICT, EBRTA with a high dose schedule appears to be an efficient and safe alternative.

Adult↗
PubMed1999

Fat balance and hepatic mitochondrial function in response to fat feeding in mature rats.

OBJECTIVE: To study the effects of fat feeding on fat balance and hepatic mitochondrial function in postpubertal male rats. DESIGN: Rats were fed low fat, medium fat or high fat diet for 15 days. MEASUREMENTS: Energy balance, body composition, resting metabolic rate (RMR), mitochondrial state 3 and state 4 oxygen consumption rates, succinic dehydrogenase (EC 1.3.99.1) and mitochondrial alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) activities. RESULTS: Rats fed medium fat or high fat diet, in comparison with rats fed low fat diet, showed a significantly greater metabolisable energy intake and energy expenditure. In addition, body energy and lipid gains were significantly higher in rats fed medium fat or high fat diet than in rats fed low fat diet. Mitochondrial respiration and enzymatic activities were not affected by fat feeding. CONCLUSION: These results indicate that in postpubertal rats fed high fat diets, the increase in energy expenditure counteracts only in part the excess fat deposition. This is probably due to the impairment in regulatory responses, and enhances thermogenesis.

Adipose Tissue↗
PubMed1999

Energy intake and utilization vary during development in rats.

Energy intake, utilization, and partitioning were determined in male Wistar rats from 25 to 180 d of age. Serum free triiodothyronine, leptin, and free fatty acid concentrations were also measured. Energy balance measurements allowed us to identify a period from 25 to 90 d, characterized by a rapid body growth rate and another from 90 to 180 d, during which body growth rate slowed. From 25 to 180 d, we found decreases in daily energy intake and expenditure, which were faster before 90 d. The first period was characterized by storage of lipid and protein. In the second period, protein deposition approached zero and the excess of ingested energy was entirely stored as fat, so that age-associated obesity began to develop. The inability of rats to maintain a stable body weight after the cessation of growth of lean body mass is not due to decreased resting metabolism but rather to a partial leptin resistance.

Adipose Tissue↗
PubMed1999

In vitro antitumour activity and cellular pharmacological properties of the platinum-iminoether complex trans-[PtCl2[E-HN=C(OMe)Me]2].

The platinum complex trans-[PtCl2¿E-HN=C(OMe)Me¿2] was compared to cisplatin for cytotoxicity towards tumour cells, and for cellular pharmacological properties in A2780 and cisplatin-resistant A2780/Cp8 ovarian cancer cells. Trans-[PtCl2¿E-HN=C(OMe)Me¿2] was comparably cytotoxic to cisplatin (mean IC50 after 72 h exposure = 6. 1 microM and 7 microM, respectively) and did not show cross-resistance in A2780/Cp8 cells (resistance factor = 0.9). Cellular accumulation measurements after treatment with equimolar drug concentrations showed that trans-[PtCl2¿E-HN=C(OMe)Me¿2] entered both A2780 and A2780/Cp8 cells much more efficiently than cisplatin, whose accumulation was reduced in A2780/Cp8 cells. Unlike cisplatin, trans-[PtCl2¿E-HN=C(OMe)Me¿2] induced rapidly cell death and cell cycle modifications of treated cells, thus indicating substantially different mechanistic properties.

Antineoplastic Agents↗
PubMed1998

Rat liver mitochondrial respiratory capacities in the transition from weaning to adulthood.

In the present study we investigated the changes in hepatic mitochondrial function in the transition from weaning to adulthood in the rat. We measured mitochondrial respiration using FAD- and NAD-linked substrates in 25 and 60 day old rats. The results show that adult rats exhibited significantly higher respiratory rates with all the substrates used except pyruvate. Our results indicate that the transition from weaning to adulthood induces important changes in hepatic mitochondrial function.

Aging↗
PubMed1998

Oxidative activity in mitochondria isolated from rat liver at different stages of development.

The purpose of this study was to evaluate the oxidative capacities in hepatic mitochondria isolated from prepubertal, young adult and adult rats (40, 90 and 180 days of age, respectively). In these rats, mitochondrial respiratory rates using FAD- and NAD-linked substrates as well as mitochondrial protein mass were measured. The results show that only the oxidative capacity of FAD-linked pathways significantly declined in mitochondria from 180-day-old rats compared with those from younger animals. When we consider FAD-linked respiration expressed per g liver, no significant difference was found among rats of different ages because of an increased mitochondrial protein mass found in 180-day-old rats. However, when FAD-linked and lipid-dependent respiratory rates were expressed per 100 g body weight, significant decreases occurred in 180-day-old rats. Therefore, the decrease in liver weight expressed per 100 g body weight rather than an impaired hepatic cellular activity may be the cause of body energy deficit in 180-day-old rats.

Animals↗
PubMed1998

Timing of breast cancer surgery within the menstrual cycle: tumor proliferative activity, receptor status and short-term clinical outcome.

We verified the variations of primary tumour steroid receptor status and proliferative activity at different times and phases (follicular vs luteal) of the menstrual cycle and their relationship with short clinical outcome in a cohort of 248 N- breast cancer patients. Steroid receptor content (ER and PgR) was evaluated by DCC assay and proliferative activity by 3H-Thymidine autoradiographic assay (TLI). Median age was 44 years, 60% of tumors were T1, and cytohistological grade was G1-2 in 54% of cases. At surgery, 57% were in the luteal phase while 43% were in the follicular phase. No significant variations were found in mean TLI or ER and PgR characteristics of the primary tumors surgically treated in different periods of the menstrual cycle; however, the ER level resulted significantly higher in 4th with respect to the 3rd week of menstrual cycle, while PgR level was higher in PgR+ cases treated during the 3rd week. The number of relapses and disease-free survival curves after 36 months median follow-up did not differ significantly for patients treated in different periods of the menstrual cycle (12% and 9% of disease relapses in luteal and follicular phases; p=n.s.). We can conclude, therefore, that TLI, ER and PgR expressions could vary significantly during menstrual cycle only in certain specific tumor subgroups.

Adult↗
PubMed1997

Energy balance and liver respiratory activity in rats fed on an energy-dense diet.

In the present study energy balance and liver respiratory activity were studied in rats fed on either a control diet or an energy-dense diet. Liver respiration was assessed both without added substrates and after the addition of hexanoate, glycerol, or sorbitol. The effect of ouabain on hexanoate-supported respiration was also determined. Metabolizable energy intake and energy expenditure increased in rats fed on an energy dense diet, but body-weight gain, as well as lipid and protein content, remained unchanged. When net energy expenditure, obtained excluding the total cost of storage, was expressed as a percentage of metabolizable energy, significant differences were found between the two groups of rats. This finding supports the presence of regulatory mechanisms in rats fed on an energy-dense diet, which are useful to counteract development of obesity. In addition, a significant increase in liver respiratory activity was found in rats fed on an energy-dense diet, both in the basal state and in that stimulated by added substrates. Na/K-pump-dependent O2 consumption also increased in rats fed on an energy-dense diet. The results indicate that a greater production of metabolic heat by the liver can contribute to the increased energy expenditure found in rats fed on an energy-dense diet.

Animal Feed↗
PubMed1997

Effect of a high-fat diet on energy balance and thermic effect of food in hypothyroid rats.

We have carried out measurements of energy balance in hypothyroid rats fed a low-fat or a high-fat diet for eighteen days. We have also measured cephalic and processing thermic effect of food (TEF) after a low-fat or a high-fat meal. Body lipid gain, carcass lipid content and gross efficiency were significantly (P < 0.05) higher in hypothyroid rats fed a high-fat diet compared with hypothyroid rats fed a low-fat diet, while metabolizable energy intake and energy expenditure remained unchanged. Cephalic TEF after a low-fat meal was significantly (P < 0.05) lower in hypothyroid rats fed a high-fat diet compared with hypothyroid rats fed a low-fat diet, while it was significantly (P < 0.05) higher after a high-fat meal than after a low-fat meal in hypothyroid rats fed a high-fat diet. No significant variation was found in processing TEF after a low-fat or a high-fat meal. Our results indicate that hypothyroid rats are unable to develop increased energy expenditure and increased TEF in response to a high-fat diet.

Animals↗
PubMed1996

Syncopal sustained ventricular tachycardia in a patient with right ventricular dysplasia.

A 41-year-old man was hospitalized for syncopal sustained ventricular tachycardia with left bundle branch morphology. Diagnostic screening confirmed a right ventricular dysplasia: fibrofatty replacement of myocardium on endomyocardial biopsy and severe dilation of right ventricle with no left ventricular impairment was documented. His bundle recording showed an abnormally long HV interval, and programmed ventricular stimulation induced high-rate sustained ventricular tachycardia with left bundle branch block morphology associated with reduced systolic blood pressure and dizziness. Right ventricular burst pacing proved to be effective in restoring sinus rhythm. A single lead pectoral cardioverter-defibrillator was implanted and programmed for VVI and antitachycardia pacing, as first ventricular tachycardia therapeutic intervention. During 6-month follow-up, 1 asymptomatic ventricular tachycardia recurrence terminated by antitachycardia pacing was reported by the device. The possible role of the other therapeutic options such as drugs, ablation, and surgery for this specific case is also discussed.

Adult↗
PubMed1996

Hepatic fatty acid-supported respiration in rats fed an energy-dense diet.

The energy balance and hepatic fatty acid-supported respiration were studied in rats fed a control or an energy-dense diet. In addition, state 3 and 4 respiratory rates as well as ketone body production with palmitoylcarnitine as substrate were determined in isolated mitochondria. Metabolizable energy intake and energy expenditure increased in rats fed an energy-dense diet, but the gain in body weight and lipid content remained unchanged. No variation occurred in the mitochondrial palmitoylcarnitine utilization rate and ketone body production, but a significant increase in the mitochondrial content of ketone bodies and the serum levels was found in rats fed an energy-dense diet. Furthermore, we have shown a significant increase in fatty acid-stimulated respiration in hepatocytes from rats fed an energy-dense diet. The enhanced hepatic fatty acid utilization as an energy substrate found in rats fed an energy-dense diet may contribute to reduce the availability of lipids for storage, thus counteracting the development of obesity.

Animals↗
PubMed1996

Thermic effect of food in hypothyroid rats.

The regulatory and obligatory components of cephalic and gastrointestinal phases of the thermic effect of food (TEF) were measured in control and hypothyroid rats. A significant decrease (P < 0.05) in regulatory and obligatory components of cephalic and gastrointestinal TEF, after either a control or energy-dense meal, was found in hypothyroid rats compared with control rats. Our findings indicate that hypothyroidism is associated with a decreased thermogenic response to food which contributes to the reduced energy expenditure of hypothyroid rats. Our results also suggest that tri-iodothyronine is involved in the regulation of postprandial thermogenesis directly as well as through its influence on beta-adrenergic response and insulin release.

Animals↗