Changes In Excretion Rates Research Articles

Prospective investigation and literature review of tolerance dose on salivary glands using quantitative salivary gland scintigraphy in the intensity-modulated radiotherapy era.

The purpose of this study was to prospectively evaluate the scintigraphic results on patients who undergo intensity-modulated radiotherapy (IMRT) to investigate the tolerance doses for the salivary glands. Salivary scintigraphy was performed on 35 patients with head and neck cancer before the beginning of radiotherapy (RT), and then at 6 weeks and again at 3 months after the completion of RT. Xerostomia was recorded according to the Radiation Therapy and Oncology Group (RTOG) grade. Salivary function was evaluated by calculating the excretion rate changes (ΔF) for each salivary gland before and after RT. The parotid mean dose was significantly related to parotid ΔF and the submandibular gland mean dose to the submandibular gland ΔF. The parotid mean dose of 23 Gy was best correlated with the RTOG grades. The submandibular gland mean dose significantly related to ΔF ≤-50% and ≤-75% was 42 Gy. The parotid mean dose of 23 Gy and the submandibular gland mean dose of 42 Gy is feasible for salivary function preservation in the IMRT era. © 2016 Wiley Periodicals, Inc. Head Neck 38: E1746-E1755, 2016.

The Fourth Dimension

Albuminuria is a powerful predictor of cardiovascular disease and death in health and a variety of disease states.[1][1],[2][2] However, once albuminuria has been detected, the value of monitoring changes in excretion rates over time is unclear and has not been tested rigorously. Furthermore,

Land use controls nutrient excretion by stream invertebrates along a gradient of agriculture

We examined the relationship between land use in the watershed and nutrient release by mayflies in streams in southcentral Ontario (Canada). Mayfly excretion rates and molar ratios of dissolved organic C (DOC), NH4+, and soluble reactive P (SRP) were measured in 6 streams flowing through watersheds with contrasting agricultural land use. Mass-specific release rates of NH4+ and SRP by mayflies and % agricultural land use (% agriculture) in the watershed were strongly positively related (r2 = 0.48, p < 0.01 and r2 = 0.58, p < 0.05, respectively). Changes in excretion rates and ratios probably were caused by lower periphyton C:N and C:P ratios associated with elevated total dissolved N and total P concentrations (r2= 0.30, p < 0.05 and r2= 0.38, p < 0.001, respectively) in streams in watersheds with high % agriculture. Mayfly mass-specific excretion rates and periphyton elemental composition were related to % agriculture, but the relatively constant body C, N, and P content in mayflies across all streams suggests strong homeostasis in these consumers. Watershed land use alters nutrient loading, which influences periphyton elemental composition and, ultimately, stoichiometry of nutrient fluxes through invertebrate consumers.

Changes in excretion rates of stress hormones in medical staff exposed to electromagnetic radiation

The aim of this paper is to study the effect of electromagnetic radiation (EMR) on the excretion rates of stress hormones of medical staff in physiotherapy. The excretion rates of stress hormones cortisol, adrenaline and noradrenaline were followed during morning shift in 15 female physiotherapists using RIA kits and a spectrofluorimetric method. The mean number of treatments with EMR emitting devices per month and the emission of each device was assessed. A control group of nurses, matched by age, sex and work task was used. The psychosocial factors were evaluated and no differences between the two groups was found. Calculations of the individual EMR exposure show levels above the ICNIRP guidelines. Significantly higher excretion rates of cortisol, adrenaline and noradrenaline among the studied physiotherapists in comparison with the control group of nurses were found. In conclusion, our data showed that EMR influenced the excretion rates of stress hormones of medical staff in physiotherapy.

Phosphorus cycling by mussels (Unionidae : Bivalvia) in Lake St. Clair

The role of mussels in cycling phosphorus in Lake St. Clair during the May–October period was examined by measuring concentrations in the water column and in mussel tissue, and by measuring rates of biodeposition and excretion. Mean rates of biodeposition and excretion for Lampsilis radiata siliquoidea, the most abundant species, were 6.3 µg P (g shell-free dry wt)-1 h-1 and 1.3 µg P (g shell-free dry wt)-1 h-1, respectively; body tissue phosphorus content was 2.7 percent of dry wt. Seasonal changes in excretion rates appeared to be related to the gametogenic cycle of the organism, but seasonal changes in biodeposition rates were not apparent. Phosphorus assimilation efficiency for this species was about 40 percent. Overall, the mussel population in Lake St. Clair filtered about 210 MT of phosphorus, or about 13.5 percent of the total phosphorus load for the May–October study period. Of this amount, about 134 MT was sedimented to the bottom via biodeposition. Mussel biodeposition may be an important source of nutrients to other biotic components in the lake such as macrophytes and invertebrate deposit-feeders.

Catecholamines during therapeutic abortion induced with intra-amniotic prostaglandin F2α

Serial plasma, amniotic fluid, and urine samples were analyzed for epinephrine (E) and norepinephrine (NE) in eight subjects during midtrimester abortion induced by intra-amniotic prostaglandin F2α (PGF2α). After PGF2α administration, plasma E increased and there was no change in plasma NE levels. Amniotic fluid levels of E and NE decreased initially. During the course of abortion the mean level of E in the amniotic fluid increased after fetal distress and decreased after fetal death, indicating that the midtrimester fetus may respond to stress by the urinary excretion of E. The maternal urinary excretion rates of both E and NE increased following PGF2α. The observation that mean plasma levels and urinary excretion rate changes correlated better with the course of abortion and uterine contractility rather than with the time of PGF2α administration was consistent with the hypothesis that the catecholamine response may be due to the stress of labor rather than to the PGF2α per se.

Effects of alpha-adrenergic blockade on renal function in hemorrhagic shock.

This study was undertaken to determine whether alpha-adrenergic blockade would reverse the altered kidney function in hemorrhagic shock. Urinary excretion of Na+, K+, and total solute were studied in 10 anesthetized dogs before and after administration of phenoxybenzamine (PBZ) in shock. Five of the 10 dogs were used to evaluate the effect of shock on renal hemodynamics. Another group of five dogs was used as controls. Normovolemic shock caused a reduction in renal blood flow (RBF) from 9.0 +/- 1 to 6.0 +/- 0.6 ml/min per kg, and an increase in renal vascular resistance (RVR) (P less than .05). When compared to the untreated shock animals, phenoxybenzamine caused an 83% increase in RBF and a 53% decrease in RVR. Treatment of control animals with phenoxybenzamine resulted in a 10-fold increase in urinary [Na+], while urinary [K+] remained unchanged. Neither urinary [K+] nor urinary [Na+] was affected significantly by PBZ in the shock group. Although the excretion rate for Na+ was increased severalfold in the untreated shocked animals when compared to controls (14.0 +/- 3 vs. 1.7 microneq/min) the excretion rates for K+ (P less than .05) and total osmotically active substances (P less than .01) diminished. Phenoxybenzamine caused significant increases in the excretion rates for Na+ and K+ in both the control and shocked dogs. The observed changes in excretion rates when PBZ was given most likely reflect drug-induced changes in renal hemodynamics.

Some observations of the effects of stress upon cortico-steroid excretion rates in the urine of scuba divers

Urine samples were obtained from scuba divers before and after dives, and on a control day. The samples were analyzed for 17-keto steroids, ketogenic (.17-OH) corticosteroids, and for K, Cl and Na. Changes in excretion rates for these were correlated with various stress measures. Only two of these were significant (p <.05), and it is concluded that excretion rates of these cortico-steroids do not constitute a sufficiently sharp measure for moderate degrees of stress.

The effect of food ingestion on the urinary excretion of calcium and magnesium

1. 1. The ingestion of a standard breakfast by normal adults resulted in a rapid increase in the rate of urinary excretion of calcium and magnesium but there was no detectable change in the levels of total or ultrafilterable calcium or magnesium in the serum. 2. 2. Similar results were observed after the ingestion of 100 g of glucose, or calcium and magnesium chloride but there was no detectable change in excretion rates after the ingestion of methyl cellulose or calcium and magnesium phosphate. 3. 3. The ingestion of a standard meal or glucose resulted in increased renal clearances of creatinine ranging from 8 to 15 ml per min. 4. 4. It is suggested that the increased excretion of calcium and magnesium following a meal is due, at least in part, to an increase in glomerular filtration rate and a consequent increase in the filtered load; this effect appears to be due mainly to the carbohydrate in the meal.

The renal excretion of hydrogen ion in renal tubular acidosis: II. Quantitative response to the carbonic anhydrase inhibitor, acetazolamide

A single test dose of the carbonic anhydrase inhibitor, acetazolamide, was given to ten normal non-acidotic subjects, two normal subjects made acidotic with ammonium chloride, four patients with renal tubular acidosis, and four patients with generalized renal disease. Changes relative to the control level were measured in the renal excretion of bicarbonate and of total hydrogen ion during the second and third hour after the administration of the drug, and the changes in the tubular reabsorption of bicarbonate were calculated. Changes in the rate of excretion of bicarbonate and in the tubular reabsorption of bicarbonate per unit of glomerular filtrate were diminished relative to the non-acidotic normal subjects in most of the patients with both types of renal disease; there was no difference relative to the normal subjects made acidotic with ammonium chloride. The change in rate of excretion of bicarbonate following enzyme inhibition varied with the filtered load of bicarbonate, and to the same extent in all groups; the same was true with respect to the relation of the serum bicarbonate concentration to the amount of bicarbonate reabsorbed per unit of glomerular filtrate. It is concluded that these observations are consistent with, but neither rule in nor rule out, deficient activity of carbonic anhydrase as one factor in the tubular impairment of proton donation in renal tubular acidosis.

THE CLOSE CORRELATION OF ANDROGEN AND CREATININE EXCRETION IN NORMAL CHILDREN1

IN A PREVIOUS STUDY (1, 1a), the urinary excretions of the 17-ketosteroids (some of which are androgenic) and estrogens in boys and girls were determined. It was shown that the 17-ketosteroids increase gradually with advancing years in both sexes; boys having a somewhat higher level than girls particularly after 11 years of age. However, the difference in the levels between the sexes was not very great. The estrogens also increase gradually with age, with a higher level in girls, especially after 10 or 11 years of age, when a marked distinction between the sexes develops, due to the appearance of a cyclic excretion in the female. The 17-ketosteroids, as far as can be ascertained, do not have cyclic changes in excretion rates, but remain at a fairly constant level at any given age period in both sexes. In order to determine the ac curacy of the collection of the 24-hour urine specimens in these cases, analyses of creatinine were also made.