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PubMed2002

Removal of dissolved organic matter from water by adsorption-flocculation using organobentonite.

Bentonite modified with short chain cationic surfactant might be the basis of a new approach to removing dissolved organic matter (DOM) from water. The treatment process involves dispersing bentonite to the DOM-containing water and then adding a small cationic surfactant to result in flocs which are agglomerates of organobentonite and bound DOM. The flocs are then removed from the solution by sedimentation. Experimental results indicate that Benzyltrimethylammonium bromide (BTMA)-bentonite displays a high affinity for DOM, most likely due to aromatic groups in the DOM molecule interacting with the benzene ring in the BTMA ion through increased pi-pi type interactions. Under appropriate operating conditions, 75% DOM removal and nearly 100% bentonite recovery could be achieved by the adsorption-flocculation process using BTMA-bentonite. Additionally, the rapid adsorption kinetics made adsorption-flocculation with BTMA-bentonite attractive for continuous treatment of large volumes of raw water. The bentonite may function as a recyclable surfactant medium for the adsorption and subsequent combustion of organic pollutants.

Adsorption↗

PubMed1988

[The feed value of pasto estrella (Cynodon nlemfuensis) of Panamanian origin in Cuba. 2. Relation of easily determined parameters of feed value and the digestibility of organic substances].

The relations between nutrient content and the digestibility of the organic matter (DOM) was to be studied in the tropical grass pasto estrella p. (Cynodon nlemfuensis) in order to draw conclusions as to the causes of changes of the feed value and to estimate DOM with the help of easily determinable parameters. Comparative studies of cellulase solubility from the organic matter also served this purpose. Grass samples from three continuous digestibility studies were used as test material. There is a strong negative dependence of DOM on the content of cell wall substances (crude fibre, lignin) which is characterized by regression coefficients (-1.68, -4.00). Due to a low average protein content changes in the crude protein content had a particularly positive influence on DOM. Regression equations are recommended for the estimation of DOM, the content of metabolizable energy and NEFUcattle from the content of crude fibre, lignin, crude protein and cellulase solubility of the organic matter (biostatistical residual dispersion = 2.1-2.3% DOM; 0.35-0.36 MJ metabolizable energy or 0.2-0.21 MJ NEFUcattle).

Animal Feed↗

PubMed2003

Efficacy of transdermal ketoprofen for delayed onset muscle soreness.

OBJECTIVE: To determine the efficacy of transdermal ketoprofen in reducing delayed-onset muscle soreness (DOMS), limiting systemic absorption, and improving postexercise function following repetitive muscle contraction. DESIGN: Double-blind, placebo-controlled clinical trial. SETTING: OrthoMed, University of California at San Diego, La Jolla, CA, U.S.A. PARTICIPANTS: Thirty-two healthy males 18 to 35 years old. INTERVENTIONS: Subjects performed a leg extension and flexion exercise program designed to create DOMS in quadriceps muscles. Subjects were randomly assigned to receive any combination of transdermal ketoprofen or placebo cream, applied TID, to their right and left quadriceps. MAIN OUTCOME MEASURES: Subjective measure of DOMS in quadriceps muscles, serum ketoprofen levels, strength index scores (a measure of postexercise function), and adverse reactions were assessed at baseline, 24 hours, and 48 hours. RESULTS: Within-subjects analysis (n = 16) showed a significant reduction in DOMS scores in legs receiving transdermal ketoprofen compared with legs receiving placebo cream (P = 0.002 at 48 hours and 0.000 at 24 and 48 hours combined). Between-subjects analysis (n = 16) showed a marginally significant reduction in DOMS scores at 48 hours (P = 0.05 in right legs and 0.053 in left legs). Systemic absorption was minimal, with serum ketoprofen levels in the ng/mL range. No differences in strength index scores were observed. No adverse reactions were reported. CONCLUSIONS: Transdermal ketoprofen appears to be effective in reducing self-reported DOMS after repetitive muscle contraction, particularly after 48 hours. Systemic absorption of the drug was minimal. Treatment did not appear to have any effect on postexercise function, and there were no reported adverse reactions.

Administration, Cutaneous↗

PubMed2006

Strong coupling between natural Planctomycetes and changes in the quality of dissolved organic matter in freshwater samples.

Dilution-regrowth experiments coupled to fluorescence in situ hybridization were conducted with samples from two humic reservoirs in order to examine how inorganic nutrients (N, P) affect free-living bacterioplankton phylogenetic groups and subsequently the quality of dissolved organic matter (DOM). The experiments were complemented by analyses of the empirical relationships between the targeted bacteria, nutrients, DOM and grazers. The ratio of absorbance of waters (A) at 250 and 365 nm (A(250 nm):A(365 nm)), which has been found to increase with the proportion of small molecules in the DOM pool in other humic waters, was used as an index of DOM quality. When nutrient stimulated bacteria, both the responses of bacterial groups (in the absence of grazers) and the ratio A(250 nm):A(365 nm) were generally different between treatments (+N, +P, +NP), suggesting that in nutrient-poor systems, differences in the type of inorganic nutrient supply will ultimately cause differences in DOM quality. The ratio A(250 nm),:A(365 nm) peaked in the +N treatments where members of the Planctomycetes (PLA) were the most stimulated group, and across treatments, PLA best explained (positive relationship) variations in this ratio. Consistent with this, the in situ data showed that the removal of the negative effects of flagellates on PLA yielded the highest R(2) in attempts to use bacterial groups to explain variations in A(250 nm):A(365 nm). These findings provide lines of evidence, not previously demonstrated in natural waters, that Planctomycetes may be an important factor changing the DOM quality, particularly in nutrient-poor systems when supplied with inorganic N.

Animals↗

PubMed2005

The effect of delayed-onset muscle soreness on stretch reflexes in human low back muscles.

The aim of the study was to investigate the effect of moderate delayed-onset muscle soreness (DOMS) on the short latency stretch reflex (SLR) and long latency stretch reflex (LLR) response i.e. electromyographic (EMG) onset latencies and EMG amplitudes in erector spinae (ES). Nine males with muscle soreness (DOMS group) were tested 24, 48 h, and 7 days post-exercise. Eight males (control group) were tested likewise. EMG was measured from ES bilaterally at the level of L3/L4. The SLR was elicited by mechanically tapping the ES at L3/L4, and the LLR was elicited by sudden loadings of the spine. Significant reductions in force during maximal voluntary contractions and range of motion, and a significant increase in muscle soreness (measured by pressure algometry) and subjective experience of soreness in the low back indicated DOMS 24, and 48 h post-exercise in the DOMS group. No changes were observed in the control group. The SLR and LLR response were unaffected by DOMS, i.e. no changes in EMG latencies and amplitudes were observed. In conclusion, despite changes in DOMS indicators, the reflex system protecting the stability of the lumbar spine is apparently capable of maintaining an appropriate triggering of SLR and LLR.

Adult↗

PubMed2004

Leukocytes, cytokines, growth factors and hormones in human skeletal muscle and blood after uphill or downhill running.

Muscular adaptation to physical exercise has previously been described as a repair process following tissue damage. Recently, evidence has been published to question this hypothesis. The purpose of this study was to investigate inflammatory processes in human skeletal muscle and epimysium after acute physical exercise with large eccentric components. Three groups of subjects (n= 19) performed 45 min treadmill running at either 4 deg (n= 5) or 8 deg (n= 9) downhill or 4 deg uphill (n= 5) and one group served as control (n= 9). One biopsy was taken from each subject 48 h post exercise. Blood samples were taken up to 7 days post exercise. Compared to the control group, none of the markers of inflammation in muscle and epimysium samples was different in any exercised group. Only subjects in the Downhill groups experienced delayed onset of muscle soreness (DOMS) and increased serum creatine kinase activity (CK). The detected levels of immunohistochemical markers for T cells (CD3), granulocytes (CD11b), leukaemia inhibitory factor (LIF) and hypoxia-inducible factor 1beta (HIF-1beta) were greater in epimysium from exercised subjects with DOMS ratings >3 (0-10 scale) compared to exercised subjects without DOMS but not higher than controls. Eccentric physical exercise (downhill running) did not result in skeletal muscle inflammation 48 h post exercise, despite DOMS and increased CK. It is suggested that exercise can induce DOMS by activating inflammatory factors present in the epimysium before exercise. Repeated physical training may alter the content of inflammatory factors in the epimysium and thus reduce DOMS.

Adolescent↗

PubMed2005

Effects of dietary carbohydrate on delayed onset muscle soreness and reactive oxygen species after contraction induced muscle damage.

BACKGROUND: Delayed onset muscle soreness (DOMS) occurs after unaccustomed exercise and has been suggested to be attributable to reactive oxygen species (ROS). Previous studies have shown increased ROS after lengthening contractions, attributable to invading phagocytes. Plasma glucose is a vital fuel for phagocytes, therefore carbohydrate (CHO) status before exercise may influence ROS production and DOMS. OBJECTIVE: To examine the effect of pre-exercise CHO status on DOMS, ROS production, and muscle function after contraction induced muscle damage. METHOD: Twelve subjects performed two downhill runs, one after a high CHO diet and one after a low CHO diet. Blood samples were drawn for analysis of malondialdehyde, total glutathione, creatine kinase, non-esterified fatty acids, lactate, glucose, and leucocytes. DOMS and muscle function were assessed daily. RESULTS: The high CHO diet resulted in higher respiratory exchange ratio and lactate concentrations than the low CHO diet before exercise. The low CHO diet resulted in higher non-esterified fatty acid concentrations before exercise. DOMS developed after exercise and remained for up to 96 hours, after both diets. A biphasic response in creatine kinase occurred after both diets at 24 and 96 hours after exercise. Malondialdehyde had increased 72 hours after exercise after both diets, and muscle function was attenuated up to this time. CONCLUSIONS: Downhill running resulted in increased ROS production and ratings of DOMS and secondary increases in muscle damage. CHO status before exercise had no effect.

Adult↗

PubMed2006

Influence of vibration on delayed onset of muscle soreness following eccentric exercise.

UNLABELLED: Delayed onset muscle soreness (DOMS), which may occur after eccentric exercise, may cause some reduction in ability in sport activities. For this reason, several studies have been designed on preventing and controlling DOMS. As vibration training (VT) may improve muscle performance, we designed this study to investigate the effect of VT on controlling and preventing DOMS after eccentric exercise. METHODS: Fifty healthy non-athletic volunteers were assigned randomly into two experimental, VT (n = 25) and non-VT (n = 25) groups. A vibrator was used to apply 50 Hz vibration on the left and right quadriceps, hamstring and calf muscles for 1 min in the VT group, while no vibration was applied in the non-VT group. Then, both groups walked downhill on a 10 degrees declined treadmill at a speed of 4 km/hour. The measurements included the isometric maximum voluntary contraction force (IMVC) of left and right quadriceps muscles, pressure pain threshold (PPT) 5, 10 and 15 cm above the patella and mid-line of the calf muscles of both lower limbs before and the day after treadmill walking. After 24 hours, the serum levels of creatine-kinase (CK), and DOMS level by visual analogue scale were measured. RESULTS: The results showed decreased IMVC force (P = 0.006), reduced PPT (P = 0.0001) and significantly increased mean of DOMS and CK levels in the non-VT group, compared to the VT group (P = 0.001). CONCLUSION: A comparison by experimental groups indicates that VT before eccentric exercise may prevent and control DOMS. Further studies should be undertaken to ascertain the stability and effectiveness of VT in athletics.

Adult↗

PubMed1993

Domperidone treatment enhances corticotropin-releasing hormone stimulated adrenocorticotropic hormone release from the dog pituitary.

While dopamine (DA) is known to inhibit pituitary intermediate lobe proopiomelanocortin (POMC) peptide secretion and synthesis in most species, its influence on anterior-lobe (AL) POMC peptide synthesis and secretion is less clear. We, therefore, sought to determine the effects of daily treatment with the DA receptor antagonist, domperidone (DOM), on secretion of the POMC peptides adrenocorticotropic hormone (ACTH) and alpha-melanocyte-stimulating hormone (alpha-MSH) from the dog pituitary, and on concentrations of another pituitary hormone regulated by DA, prolactin (PRL). Dogs treated for 7 days with DOM had significantly higher peak ACTH concentrations in response to corticotropin-releasing hormone (CRH) injection (329 +/- 37 pg/ml, mean +/- SD) than did controls (164 +/- 42 pg/ml). PRL was also significantly (p < 0.05) increased in samples collected on a daily basis after DOM injections (9.5 +/- 4.6 vs. 4.3 +/- 3.3 ng/ml in controls). However, plasma alpha-MSH concentrations were unaffected by DOM. In a subsequent study, dogs were again treated daily with DOM or vehicle (controls), and additionally were given dexamethasone (DEX) to block AL ACTH release. DEX-treated controls showed low daily and CRH-stimulated ACTH and cortisol concentrations (generally below assay sensitivity). In contrast, DEX + DOM-treated dogs had daily mean ACTH concentrations ranging from 10 +/- 8.1 to 32 +/- 26 pg/ml and mean peak post-CRH ACTH concentrations of 174 +/- 16 pg/ml. Although daily cortisol concentrations were below assay sensitivity, the mean peak post-CRH cortisol concentration was 6.7 +/- 1.8 micrograms/dl, indicating that the immunoreactive ACTH was biologically active.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

PubMed1989

A sex-specific endogenous stimulatory rhythm regulating prolactin secretion.

In the rat, PRL secretion is under inhibitory control by tuberoinfundibular dopaminergic neurons. The levels of dopamine (DA) in hypophysial portal blood decline during surges of PRL secretion (e.g. suckling and cervical stimulation). However, this decline alone is not sufficient to account for the amount of PRL released. In this study we investigated the possible existence of an endogenous stimulatory rhythm for PRL secretion that may be masked by the tonic inhibitory tone of DA and unmasked by the DA-lowering effects of cervical stimulation. The PRL secretory response to pharmacological depression of DA-ergic tone was studied in ovariectomized (OVX) female, adult castrated (AC) male, neonatally androgen-sterilized (TP) female, and neonatally castrated (NC) male rats. Since mated rats have serum PRL surges at 0300 and 1700 h, these groups were treated with 200 micrograms/kg domperidone (DOM), iv, at 0300 h, 1700 h, or the intersurge interval, 1200 h. Serial blood samples were collected immediately before and at frequent intervals after DOM injection. OVX female rats had significantly greater serum PRL responses to DOM at 0300 and 1700 h than at 1200 h. AC male rats secreted significantly less PRL in response to DOM compared to OVX rats, and their PRL responses to DOM were similar at all three times. TP female rats had PRL secretory responses similar to those of the OVX rats at 1200 h, and the responses at 0300 and 1700 h were similar. NC male rats had PRL secretory responses similar to those of AC male rats. There was no difference between the PRL secretory profiles at any time after DOM injection in NC rats. These data provide evidence for an endogenous stimulatory rhythm for PRL secretion that is specific to female rats. They further suggest that the neonatal steroid environment is critical for differentiation of some sexually specific characteristics.

Animals↗

PubMed1989

Hypothalamic factors involved in the endogenous stimulatory rhythm regulating prolactin secretion.

We recently reported that acute pharmacologic depression of dopaminergic tone at different times of day unmasks a sex-specific endogenous stimulatory rhythm regulating PRL secretion. The PRL secretory responses of ovariectomized rats to the dopamine antagonist domperidone (DOM) were higher at 0300 and 1700 h than at 1200 h. These are the times during which surges of PRL appear in mated rats. This experimental paradigm was used to investigate the roles of the putative PRL-releasing factors (PRFs) oxytocin (OT), vasoactive intestinal peptide (VIP), and serotonin (5-HT) in this rhythm. The role of OT was studied by infusion of the OT antagonist 1-deamino-2-D-Trp-4-Val-8-Orn-Oxytocin (OT-A, 0.5 microgram/kg min) for 6 h. Two hours after beginning the OT-A infusion DOM was administered, as a single injection of 200 micrograms/kg iv at either 0300, 1200, or 1700 h. Serial blood samples were collected immediately before and 5, 10, 20, 30, 60, 120, 180, and 240 min after DOM administration. Infusion of OT-A attenuated the heightened PRL secretory responses to DOM given at both 0300 and 1700 h but did not affect the response at 1200 h. The role of VIP was studied by infusing the VIP antagonist [D, 4-Cl-Phe6,Leu17] VIP (VIP-A, 0.1 microgram/kg.min) as described above. VIP-A infusion had no effect on the PRL secretory responses to DOM given at 1200 or 1700 h but attenuated the heightened response at 0300 h. In order to study the role of 5-HT in the rhythm, rats were pretreated with p-chlorophenylalanine (250 mg/kg sc) 48 and again 24 h before the experiment. Pretreatment with p-chlorophenylalanine had no effect on the PRL secretory responses to DOM given at 0300 or 1200 h, but it attenuated the augmented PRL secretory response at 1700 h. These data suggest that both VIP and OT act as endogenous PRFs at 0300 h and 5-HT and OT act as PRFs at 1700 h. We propose that VIP and 5-HT are continuously active oscillatory neurotransmitters regulating OT release into pituitary portal blood and that these daily events only eventuate in PRL release when the mating stimulus has release the lactotroph from the inhibitory effects of dopamine.

Animals↗

PubMed1991

Ontogeny of the endogenous stimulatory rhythm regulating prolactin secretion in immature female rats.

PRL secretion in the female rat is regulated by an endogenous stimulatory rhythm (ESR). This rhythm consists of two components: a nocturnal (N) component whose activity is greatest by 0300 h and a diurnal (D) component that peaks at approximately 1700 h. This periodicity coincides with the periods of the N and D surges of PRL in responses to the mating stimulus. Furthermore, we have shown that the ESR is involved in the regulation of mating-induced PRL surges. Mating causes a lowering of dopaminergic tone which reveals the ESR for PRL. The ability of immature female rats to express PRL surges induced by copulomimetic stimuli begins at 25 days of age. In this study we investigated the ontogeny of the ESR in immature female rats in order to observe the relationship between the onset of PRL secretion induced by copulomimetic stimuli and the development of the ESR. Immature female rats were raised in our colony and kept with their dams until used in an experiment or weaned at 23 days of age where appropriate. At 15, 20, 23, 24, 25, or 30 days of age female rats received a single ip injection of domperidone (DOM; 5 mg/kg) or saline vehicle at 0300, 1200, or 1700 h. Thirty minutes after the injection the rats were decapitated, and trunk blood was collected. PRL was measured by RIA. DOM had no effect on PRL secretion as compared to that in saline-treated controls at 15 days of age. However, in all other age groups DOM induced a significant increase in PRL levels compared to those in saline-treated animals regardless of the time of injection. In addition, there was no time of day difference in the PRL secretory response to DOM in rats 15-23 days of age. However, rats treated with DOM at 0300 h at 24 days of age secreted approximately 2-fold greater PRL than rats treated similarly at 1200 or 1700 h. Moreover, at 25 and 30 days of age, rats treated with DOM at either 0300 or 1700 h secreted significantly greater PRL than rats treated similarly at 1200 h. These results suggest that the ESR for PRL secretion begins by 24 days of age. In addition, they indicate that the hypothalamic developmental event preceding and required for expression of mating-induced surges of PRL is the establishment of the ESR.

Aging↗

PubMedDate not supplied

Comparison of changes in metal toxicity following exposure of water with high dissolved organic carbon content to solar, UV-B and UV-A radiation.

This study examines the effects of natural solar radiation on the metal-binding capacity of dissolved organic matter (DOM). Newington Bog water (35.5 mg L(-1) dissolved organic carbon [DOC]) was irradiated for 20 days under UV-B lamps in the laboratory and under natural solar radiation. In the presence of irradiated DOM, IC(50) (contaminant concentration required to reduce algal growth by 50%) was significantly decreased with UV-B treatment for four metals: Pb, 64%; Cu, 63%; Ni, 35% and Cd, 40%. Solar radiation also significantly decreased IC(50) of Pb (58%) and Cu (49%), DOC concentration (11%), DOM fluorescence (DOMFL, 33%) and DOC-specific UV absorbance. Further experiments on Raisin River water (20.7 mg DOC L(-1)) exposed to 20 days of artificial UV-A and UV-B radiation produced significant decreases in IC(50) for Cu (48%) with UV-A and for Pb (43%) with UV-B. DOC concentration was decreased 20% by UV-B and 24% by UV-A. DOMFL decreased 51.5% in the first 5 days of UV-A exposure, an effect that was not observed with the UV-B treatment. The UV-A treatment decreased UV absorbance more at longer wavelengths and over a broader wavelength band than did the UV-B treatment. Change in toxicity with UV irradiation was inconsistent among the metals tested in this study, indicating that some organic metal-binding ligands were more quickly removed or altered than others. The DOM remaining after irradiation appears to be qualitatively different from the unirradiated DOM. The much greater irradiance of UV-A makes its contribution to the removal and/or alteration of DOM at least as important as the influence of higher energy UV-B.

Biological Assay↗

PubMedDate not supplied

Interactions of organic compounds with wastewater dissolved organic matter: role of hydrophobic fractions.

The role of structural fractions of dissolved organic matter (DOM) from wastewater in the sorption process of hydrophobic organic compounds is still not clear. In this study, DOM from two wastewater treatment plants (Lachish and Netanya, Israel) was fractionated to hydrophobic acid (HoA) and hydrophobic neutral (HoN) fractions. The fractions were characterized and their sorptive capabilities for s-triazine herbicides and polycyclic aromatic hydrocarbons (PAHs) were studied. For all sorbates, the binding to the HoN fractions was much higher than to HoA fractions. The HoA fractions were more polar than the HoN fractions, containing a higher level of carboxylic functionalities. However the higher binding coefficients of atrazine (2-chloro-4-ethylamine-6-isopropylamino-s-triazine) and ametryn [2-(ethylamino)-4-isopropylamino-6-methyl-thio-s-triazine] obtained for the HoN fractions suggest that their sorption is governed by hydrophobic-like interactions rather than H bonding. The values of binding coefficients of PAHs measured for the HoN fractions were within the range reported for humic acids and much higher than other fractions, suggesting that this fraction plays an important role in the overall sorption of these compounds by DOM. Higher sorption coefficients were measured for the Netanya DOM sample containing higher level of hydrophobic fractions (HoA + HoN) than the Lachish DOM, suggesting that the sorption of hydrophobic organic compounds by DOM is governed by the level of these structural substances. The evaluation of mobility of organic pollutants by wastewater irrigation requires not only assessment of the total carbon concentration but also, more importantly, the content of the hydrophobic fractions.

Adsorption↗

PubMed2006

Wastewater dissolved organic matter: characteristics and sorptive capabilities.

An evaluation of the mobility of organic pollutants with wastewater dissolved organic matter (DOM) is essential to better understanding their fate and toxicity to the environment. In this study, DOM from two wastewater treatment plants (in Lachish and Netanya, Israel) were fractionated to hydrophobic-acid (HoA) and hydrophobic-neutral (HoN) fractions. The fractions were characterised and their sorptive capabilities for s-triazine herbicides and polycyclic aromatic hydrocarbons (PAHs) were studied. For all sorbates, binding to the HoN fractions was much higher than to HoA fractions. The high binding coefficients obtained for the studied triazines by the HoN fractions suggested that their sorption is governed by hydrophobic-like interactions rather than H-bonding. The binding coefficients of PAHs measured for the HoN fractions were within the range reported for humic acids and much higher than for the HoA fraction, suggesting that the HoN fraction plays an important role in the overall sorption of these compounds by DOM. Higher sorption coefficients were measured for the Netanya DOM sample containing a higher level of hydrophobic fractions (HoA + HoN) than the Lachish DOM, suggesting that the sorption of hydrophobic organic compounds by DOM is governed by the relative content of these structural substances.

Humic Substances↗

PubMed1988

The effect of dopamine antagonists and/or VIP on TRH- or VIP-induced prolactin release in estrogen- and progesterone-treated ovariectomized rats.

These experiments were conducted to test the hypothesis that the effectiveness of VIP in releasing prolactin is, like TRH, enhanced when preceded by a short period of dopamine receptor antagonism. Chronically catheterized, ovariectomized rats pretreated with estradiol benzoate and progesterone to mimic early pregnancy were used throughout these studies. In the first experiment, animals were injected either with the dopamine (DA) antagonist domperidone (DOM, 0.01 mg/rat, iv) or with vehicle (acetic acid in saline). Five minutes later, all animals were treated with the DA agonist 2-Br-alpha-ergocryptine maleate (CB-154, 0.5 mg/rat, iv) followed 60 min later by the administration of thyrotropin-releasing hormone (TRH, 1.0 micrograms/rat iv) or vasoactive intestinal peptide (VIP, 25 micrograms/rat, iv). The injection of TRH following DOM treatment increased mean plasma PRL levels 100 ng/ml above levels found in vehicle-injected rats. VIP administration, however, increased PRL levels in the blood in DOM-treated rats only 6 ng/ml above the levels in vehicle-injected animals. The same treatment protocol was used in the second experiment except that the DA antagonist, sulpiride (0.01 mg/rat, iv) was administered instead of DOM, and CB-154 was not given. In this experiment both TRH and VIP released PRL. The response to TRH, but not to VIP, was significantly greater following sulpiride than in animals treated with sulpiride vehicle. In the third experiment animals were treated with DOM, VIP, DOM plus VIP, or vehicle. Five minutes later all rats received CB-154 injections, followed 60 min later by TRH administration. The final experiment was a replicate of the third except that sulpiride was substituted for domperidone and no CB-154 was given. The resulting data revealed that (1) dopamine antagonism enhanced the effectiveness of TRH but not VIP and (2) that VIP augmented the effectiveness of DA blockade on PRL release and was additive with domperidone (but not sulpiride) on increasing the responsiveness to TRH. However, VIP administration without concurrent administration of domperidone or sulpiride did not increase the effectiveness of TRH compared to vehicle-injected animals. From these data we concluded that VIP is a PRL-releasing hormone the effect of which is not affected by interruption in dopamine tone as is observed for TRH. Second, VIP can potentiate the stimulatory actions of at least one DA receptor antagonist and TRH on PRL release. This later finding suggests that VIP may play a modulatory role in the neuroendocrine regulation of PRL secretion in the female rat.

Animals↗

PubMed1993

Microscale characterization of dissolved organic matter production and uptake in marine microbial mat communities.

Intertidal marine microbial mats exhibited biologically mediated uptake of low molecular weight dissolved organic matter (DOM), including D-glucose, acetate, and an L-amino acid mixture at trace concentrations. Uptake of all compounds occurred in darkness, but was frequently enhanced under natural illumination. The photosystem 2 inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU) generally failed to inhibit light-stimulated DOM uptake. Occasionally, light plus DCMU-amended treatments led to uptake rates higher than light-incubated samples, possibly due to phototrophic bacteria present in subsurface anoxic layers. Uptake was similar with either 3H- or 14C-labeled substrates, indicating that recycling of labeled CO2 via photosynthetic fixation was not interfering with measurements of light-stimulated DOM uptake. Microautoradiographs showed a variety of pigmented and nonpigmented bacteria and, to a lesser extent, cyanobacteria and eucaryotic microalgae involved in light-mediated DOM uptake. Light-stimulated DOM uptake was often observed in bacteria associated with sheaths and mucilage surrounding filamentous cyanobacteria, revealing a close association of organisms taking up DOM with photoautotrophic members of the mat community. The capacity for dark- and light-mediated heterotrophy, coupled to efficient retention of fixed carbon in the mat community, may help optimize net production and accretion of mats, even in oligotrophic waters.

Amino Acids↗

PubMedDate not supplied

Evaluation of the Drug-O-Matic automated dispensing system.

OBJECTIVE: To compare the time savings and accuracy rates of a manual dispensing system with the Drug-O-Matic (DOM), an automated tablet and capsule counter. DESIGN: In part one, phase A of this two-part study, a time trial measured the time of the prescription-filling process using the manual method. In part one, phase B, a time trial measured the time of that process using the DOM system. Part two of the study measured the accuracy of the DOM. RESULTS: The DOM requires 9 hours 42 minutes less per day than does the manual system. However, its accuracy causes some concern because we found a 14 percent discrepancy rate in terms of over- and underfills. CONCLUSIONS: Our initial experience with the DOM suggests significant time-savings potential compared with the manual method of prescription filling, and our institutional goal is to translate the time saved into other activities that will allow us to function as a free-standing pharmacy. A concern is the DOM's 14 percent discrepancy rate. Further studies are needed to confirm or challenge our initial findings.

Automation↗