Early detection of metabolic and energy disorders by thermal time series stochastic complexity analysis.

Maintenance of thermal homeostasis in rats fed a high-fat diet (HFD) is associated with changes in their thermal balance. The thermodynamic relationship between heat dissipation and energy storage is altered by the ingestion of high-energy diet content. Observation of thermal registers of core temperature behavior, in humans and rodents, permits identification of some characteristics of time series, such as autoreference and stationarity that fit adequately to a stochastic analysis. To identify this change, we used, for the first time, a stochastic autoregressive model, the concepts of which match those associated with physiological systems involved and applied in male HFD rats compared with their appropriate standard food intake age-matched male controls (n=7 per group). By analyzing a recorded temperature time series, we were able to identify when thermal homeostasis would be affected by a new diet. The autoregressive time series model (AR model) was used to predict the occurrence of thermal homeostasis, and this model proved to be very effective in distinguishing such a physiological disorder. Thus, we infer from the results of our study that maximum entropy distribution as a means for stochastic characterization of temperature time series registers may be established as an important and early tool to aid in the diagnosis and prevention of metabolic diseases due to their ability to detect small variations in thermal profile.

Early detection of metabolic and energy disorders by thermal time series stochastic complexity analysis

Maintenance of thermal homeostasis in rats fed a high-fat diet (HFD) is associated with changes in their thermal balance. The thermodynamic relationship between heat dissipation and energy storage is altered by the ingestion of high-energy diet content. Observation of thermal registers of core temperature behavior, in humans and rodents, permits identification of some characteristics of time series, such as autoreference and stationarity that fit adequately to a stochastic analysis. To identify this change, we used, for the first time, a stochastic autoregressive model, the concepts of which match those associated with physiological systems involved and applied in male HFD rats compared with their appropriate standard food intake age-matched male controls (n=7 per group). By analyzing a recorded temperature time series, we were able to identify when thermal homeostasis would be affected by a new diet. The autoregressive time series model (AR model) was used to predict the occurrence of thermal homeostasis, and this model proved to be very effective in distinguishing such a physiological disorder. Thus, we infer from the results of our study that maximum entropy distribution as a means for stochastic characterization of temperature time series registers may be established as an important and early tool to aid in the diagnosis and prevention of metabolic diseases due to their ability to detect small variations in thermal profile.

Factors influencing the non-recovery of renal function after the relief of urinary tract obstruction in women with cancer of cervix.

OBJECTIVES: To identify factors associated with non-recovery of renal function after the relief of urinary tract obstruction in women with cancer of cervix. PATIENTS AND METHODS: Thirty-seven women with cancer of cervix and obstructive renal failure were prospectively studied. Patients were evaluated in the day before nephrostomy (D0); and in the 1st (D1), 7th (D7), and 30th day (D30) after unilateral nephrostomy. The following parameters were analyzed: age serum urea, and serum creatinine (S(creat)), in D0, D7, and D30. Renal cortical thickness was measured by ultrasonography in D0. During nephrostomy procedure, urine samples for urinalysis and culture were collected and renal biopsy was attempted. Patients were divided in two groups according to S(creat) in D30: patients with S(creat) < 1, 4mg/dL (R group) and those with S(creat) > or = 1, 4mg/dL (nR group). RESULTS: Ten patients died before D30 and were not studied. R group (n = 12) was younger (43 +/- 9 vs. 52 +/- 10 years, p < 0.05) than nR group (n = 15), and presented lower serum urea in D0 (134 +/- 67 vs. 212 +/- 51 mg/dL, p < 0.01) and in D7 (94 +/- 20 vs. 155 +/- 18 mg/dL, p < 0.05). Renal cortex was thicker in R group (17 +/- 1 vs. 13 +/- 1 mm, p < 0.05). Survival was higher in R group (11/12) than in nR group (0/15, p < 0.01). All urine samples showed leukocyturia but culture was positive in only two. In three out of nine biopsy attempts enough material was obtained. Light microscopy revealed interstitial fibrosis plus tubular atrophy, and partial glomerular fibrosis was present in two biopsies. CONCLUSIONS: The non-recovery of renal function after the relief of obstruction in human obstructive renal failure is associated with older age and decreased renal cortical thickness. The complete renal recovery improves patient survival despite malignancy.