Alterations in energy balance with exercise

The doubly labeled water method for measuring average daily metabolic rate (ADMR) in combination with resting metabolic rate (RMR) allows one to assess the relation between exercise and energy balance. Three topics were included in an analysis of available data: 1) the limits of energy turnover in relation to physical performance for the achievement of energy balance, 2) the effect of an exercise intervention on daily energy turnover and its components, and 3) the effect of exercise on body composition. In the general population, physical activity level (PAL: ADMR/RMR) ranges between 1.2 and 2.2-2.5. There is no sex difference in the level of physical activity. Higher PAL values can be maintained by training and supplementation of the diet with energy-dense, carbohydrate-rich formulas. Exercise training does not influence spontaneous activity except in the elderly. In sedentary subjects, exercise training does not influence RMR when body weight is maintained. An exercise-induced increase in ADMR is about twice the training load. Exercise induces an increase in fat-free mass, especially in women, and a decrease in fat mass. Women tend to preserve energy balance and consequently loss of fat mass is significantly less.     

Diffusion coefficients in the lateral intercellular spaces of Madin-Darby canine kidney cell epithelium determined with caged compounds

The diffusion coefficients of two caged fluorescent dyes were measured in free solution and in the lateral intercellular spaces (LIS) of cultured Madin-Darby canine kidney (MDCK) cells after photoactivation by illumination with a continuous or pulsed UV laser. Both quantitative video imaging and a new photometric method were utilized to determine the rates of diffusion of the caged fluorescent dyes: 8-((4,5-dimethoxy-2-nitrobenzyl)oxy)pyrene-1,3,6-trisulfonic acid (DMNB-HPTS) and (4,5-dimethoxy-2-nitrobenzyl) fluorescein dextran (10,000 MW) (DMNB-caged fluorescein dextran). The diffusion coefficients at 37 degrees C in free solution were 3.3 x 10(-6) cm2/s (HPTS) and 0.98 x 10(-6) cm2/s (10,000 MW dextran). Diffusion of HPTS within nominally linear stretches of the LIS of MDCK cells grown on glass coverslips was indistinguishable from that in free solution, whereas dextran showed a 1.6 +/- 0.5-fold reduction in diffusivity. Measurements of HPTS diffusion within the LIS of multicellular regions also exhibited a diffusivity comparable to the free solution value. The restriction to diffusion of the dextran within the LIS may be due to molecular hindrance.     

27Al-NMR studies of aluminum transport across yeast cell membranes

Aluminum (Al) transport across yeast cells was studied using Dy(NO3)3 as a shift reagent by 27Al-NMR spectroscopy. The results showed that (a) Al enters the yeast cells at 15 min and over a period of time, within 4 h, an equilibrium sets in between outside and inside Al; (b) citrate does not favor Al going into the yeast cells at pH 5.0; and (c) EDTA brings out all the Al that has entered the yeast cells.     

Endoscopic biopsies and cytologic brushings of the esophagus are diagnostically complementary

Assessment of compliance in drug taking is a problem in a crowded Outpatient Department. Using riboflavin as a urinary marker is a simple and rational method. Identifying riboflavin in the urine by fluorescence on exposure to ultraviolet (UV) rays or torch light is being used in medical practice but not extensively. In this study, the validity and reliability of these methods were assessed. The sensitivity and specificity of this test by UV method was 86% and 82% for Reader I (medical person) and 82% and 94% for Reader II (paramedical person). For Reader I, the accuracy of reading by UV lamp was the same as torch light (85%) whereas for Reader II the accuracy was better with UV lamp (87%) than with torch (79%). In reading the fluorescence by UV lamp the crude agreement between the 2 readers was 82% and chance corrected agreement was 64%. UV lamp method appears to be a reliable way of assessing compliance both by medical and paramedical persons whereas torch method appears to be more reliable when used by a medical person than by a paramedical person.     

Rationale for en bloc vein resection in the treatment of pancreatic adenocarcinoma adherent to the superior mesenteric-portal vein confluence. Pancreatic Tumor Study Group

The enzymatic activity of protein kinase C (PKC) was measured in the cytosol and particulate fraction of parabrachial nucleus, the presumed site of conditioned taste aversion (CTA) engrams. At various time intervals after acquisition of the task (pairing saccharin consumption with subsequent LiCl poisoning) the nucleus was dissected from the frozen coronal sections. An increase (+40%) in the cytosol PKC activity was found 48 h after that pairing in comparison with controls (saline injection instead of LiCl). Particulate enzyme activity virtual did not change (-5%). Thus the total PKC activity increased significantly (21%). Qualitatively similar but less markedly expressed PKC shifts (+18% in cytosol) ere found 24 h following CTA. Twelve hours and 5 days after CTA acquisition the activity and distribution of PKC was similar to that seen in normal rats. The control experiments revealed that 6 h after LiCl injection alone (without previous saccharin consumption) translocation of PKC from the cytosol to the membrane fraction (found previously 1 h after LiCl injection alone) still persisted but did not differ from that found 6 h after its pairing with saccharin drinking (CTA). It is concluded that acquisition of conditioned taste aversion may be followed by synthesis of PKC rather than by its translocation or downregulation.     

Sex difference and testosterone modulation of pheromone-induced NeuronalFos in the Ferret's main olfactory bulb and hypothalamus

A carnivore, the ferret possesses a vomeronasal organ--accessory olfactory bulb (VNO-AOB) projection to the hypothalamus; however, little is known about its function. Pheromones in soiled bedding from estrous female ferrets or an artificial peppermint odor significantly augmented nuclear Fos protein immunoreactivity (Fos-IR), a marker of neural activation, in several main olfactory bulb (MOB) sites but not in the AOB of gonadectomized male and females. Testosterone propionate (TP) significantly augmented the MOB's neuronal Fos responses to estrous females' pheromones, but not to peppermint. Estrous odors, but not peppermint, also augmented neuronal Fos-IR in the medial preoptic area (mPOA) of female, but not male, subjects. Pheromones in soiled bedding from breeding male ferrets significantly augmented neuronal Fos-IR in the MOB and in the medial amygdala of gonadectomized, TP-treated male and female subjects. Again, male pheromones failed to influence neuronal Fos-IR in the AOB of either sex, and only females showed significant increases in neuronal Fos-IR in the lateral aspect of the ventromedial nucleus and mPOA. These results point to an essential role among higher mammals of the main olfactory epithelium-MOB projection to the hypothalamus in detecting and processing pheromones. Gonadectomized ferrets showed significant increases in sniffing behavior when placed on either female or male bedding. This occurred regardless of whether they had received TP or oil vehicle, suggesting that testosterone's facilitation of neuronal Fos responses to estrous females' odors in the MOB of both sexes cannot be attributed to increased scent gathering. Androgen receptor-IR was present in the MOB granule cell layer of male and female ferrets, raising the possibility that testosterone acts directly on these cells to augment their responsiveness to pheromones.