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PubMed1999

The effect of a prophylactic dose of flurbiprofen on muscle soreness and sprinting performance in trained subjects.

The aim of this study was to examine the effects of a prophylactic dose of a local, transcutaneously administered, non-steroidal anti-inflammatory drug on muscle soreness, muscle damage and sprinting performance in young trained males. Twenty-five subjects aged 19+/-3 years, actively participating in rugby union and field hockey, were familiarized with the test procedure and then divided at random into an experimental group (n = 13) and a control group (n = 12). The experimental group received two patches, each containing 40 mg flurbiprofen (TransAct LAT), 12 h before an exercise bout designed to produce delayed-onset soreness (DOMS). The control group received identical non-medicated placebo patches at the same time. Delayed-onset muscle soreness was induced by an exercise protocol consisting of drop jumps (seven sets of 10 repetitions). Serum creatine kinase activity, muscle soreness, muscle girth and acceleration in a maximal sprint over 30 m were measured before the induction of DOMS and at 12, 24, 48 and 72 h thereafter. Plasma lactate concentration was measured 3 min after the 30-m sprint tests. Subjects in both groups had significantly more pain at 24 and 48 h compared with at 12 and 72 h (P < 0.05; Friedman two-way analysis of variance). Thigh girth and serum creatine kinase did not change throughout the experiment. Although plasma lactate concentrations were elevated after the 30-m sprint, there were no differences between groups or as a result of DOMS. The greatest acceleration occurred between 5 and 10 m. This was not affected by the anti-inflammatory drug or DOMS. In conclusion, the aetiology of the DOMS induced in the trained subjects in this study seems to be independent of inflammatory processes or, more specifically, of increases in prostaglandin synthesis in the muscles.

Adult↗

PubMed1993

The effects of static and ballistic stretching on delayed onset muscle soreness and creatine kinase.

The purpose of this study was to determine if static and ballistic stretching would induce significant amounts of delayed onset muscle soreness (DOMS) and increases in creatine kinase (CK). Twenty males were randomly assigned to a static (STATIC) or ballistic stretching (BALLISTIC) group. All performed three sets of 17 stretches during a 90-min period, the only group difference being that STATIC remained stationary during each 60-s stretch while BALLISTIC performed bouncing movements. Subjective ratings of DOMS (scale: 1-10) and serum CK levels were assessed before and every 24 hours post stretching, for 5 days. A repeated measures ANOVA revealed a significant main effect due to time (p < 0.05), with peak soreness occurring at 24 hours after (M = 2.8 +/- 1.6). Surprisingly, a group effect (p < .05) demonstrated that DOMS was significantly greater for STATIC than for BALLISTIC. At 24 hours there was a 62% (p < .05) increase in CK for combined groups. These findings indicate that similar bouts of static and ballistic stretching induce significant increases in DOMS and CK in subjects unaccustomed to such exercise. Furthermore, static stretching induced significantly more DOMS than did ballistic.

Adult↗

PubMed1983

[Factors altering allantoin excretion by sheep and goats].

We have studied the factors of variation of the urinary allantoin excretion with sheep billy goats and goats during digestibility trials. The urinary excretion of nitrogen allantoin (Nal) is highly correlated with the intake of digestible organic matter (DOM) and soluble nitrogen (Ns) for the sheeps billy goats and goats. By multiple regression we have estimated the daily endogenous excretion of Nal at 160 mg (goats) and 60 mg (sheeps and billy goats) respectively 8.5 and 2.6 mg/kg W0.75. The differences observed between sheeps and billy goats (Nal = 27.3 +/- 11.3 and 32.2 +/- 9.4 mg/kg W0.75) agree with the differences observed in the DOM and Ns intakes. The dairy goats eat more than the billy goats (69.5 against 52.0 DOM/kg W0.75 and 412 against 315 mg Ns/kg W0.75) but they excrete less Nal (36.3 mg against 42.3/kg W0.75). During the first two weeks of lactation the goats with negative N balance excrete more Nal than the goats with positive N balance (78 mg Nal against 57 mg/100 g DOM). Although large variations of DOM and Ns, the amount of Nal excreted before and after kidding doesn't vary. In these last conditions the general relation between Nal and intake of DOM and Ns no longer holds. Since the disponible energy (MOD) and soluble nitrogen intake supplies for the rumen microorganisms influence the amount of synthetised microbials protein (and so the amount of nucleic acids entering the duodenum) our regressions confirm the assumption that the excretion of Nal is related with the nucleic acids metabolism. However when Nal is utilised as an index of the nucleic acids catabolism, the factors that are able to create the variations either in the endogenous production of allantoin (uterine involution, bodily mobilisation, foetus growth, mammary gland development) or in the nucleic acids valorization must be taken into account.

Allantoin↗

PubMed2006

Effect of phototherapy on delayed onset muscle soreness.

OBJECTIVE: The purpose of this study was to investigate the effects of phototherapy on delayed onset muscle soreness (DOMS) as measured using the Visual Analog Scale (VAS), McGill Pain Questionnaire, Resting Angle (RANG), and girth measurements. BACKGROUND DATA: Previous research has failed to prove the beneficial effects of phototherapy on DOMS. METHODS: This was a randomized double-blind controlled study with 27 subjects (18-35 years) assigned to one of three groups. The experimental group received 8 J/cm2 of phototherapy each day for five consecutive days using super luminous diodes with wavelengths of 880 and visible diodes of 660 nm at three standardized sites over the musculotendinous junction of the bicep. The sham group received identical treatment from a dummy cluster. The controls did not receive treatment. The study was completed over five consecutive days: on day one baseline measurements of RANG and upper arm girths were recorded prior to DOMS induction. On days 2-5, RANG, girth, and pain were assessed using VAS and the McGill Pain Questionnaire. RESULTS: The experimental group exhibited a significant decrease in pain associated with DOMS compared to the control (p=0.01) and sham groups (p=0.03) based upon the VAS at the 48-h period. The McGill Pain Questionnaire showed a significant difference in pain scores at the 48-h period between the experimental and the sham groups (p=0.01). There were no significant differences day to day and between the groups with respect to girth and RANG. CONCLUSION: The results of this study provide scientific evidence that phototherapy as used in this study provides a beneficial effect to patients who may experience DOMS after a novel exercise session.

Adolescent↗

PubMed1994

Effect of somatotropin and/or equine chorionic gonadotropin on serum and follicular insulin-like growth factor I and insulin-like growth factor binding proteins in cattle.

We investigated the effect of administration of somatotropin (ST) and/or eCG on insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBP) in serum and follicular fluid (FFL) of cattle actively immunized against growth hormone-releasing factor (GRF). Cyclic beef cattle, previously immunized against GRF-(1-29)-Gly-Gly-Cys-NH2 conjugated to human serum albumin (synthesized and provided by Hoffmann-LaRoche, Inc., Nutley, NJ; GRFi, n = 31) or to human serum albumin alone (HSAi, n = 26), received (i.m.): 1) 25 mg recombinantly derived methionyl somatotropin (rbST, n = 14; sometribove provided by Monsanto Co., St. Louis, MO); 2) 1100 IU eCG (n = 10); 3) rbST and eCG (rbST-eCG, n = 15); or 4) vehicle (VEH, n = 17) at 0 and 24 h after receiving prostaglandin F2 alpha (PGF2 alpha). Serum samples were collected at 0 and 40 h after PGF2 alpha, and the ovary bearing the largest follicle (DOM) was removed 44.0 +/- 0.5 h after PGF2 alpha; FFL was harvested from DOM and the subordinate follicle (SUB). Before treatment (0 h), GRFi cows had lower serum ST (0.6 +/- 0.2 vs. 2.2 +/- 0.2 ng/ml; p < 0.01) and IGF-I (26 +/- 4 vs. 72 +/- 4 ng/ml; p < 0.01), but greater IGFBP-2 (594 +/- 48 vs. 384 +/- 52 ng/ml; p < 0.01) than HSAi cows. Serum and FFL concentrations of IGF-I or IGFBP-2 were not different between rbST- and rbST-eCG-treated cows or between VEH- and eCG-treated cows at Hour 40 after the initial treatment injection; therefore, data were combined and designated as rbST and VEH, respectively. Serum IGF-I was increased to a greater extent (percentage increase above 0 h) by rbST treatment in GRFi (362 +/- 24) than in HSAi (176 +/- 16) cows (immunization by treatment, p < 0.01). Across GRFi and HSAi, rbST lowered serum IGFBP-2 (342 +/- 31 vs. 541 +/- 27 ng/ml, rbST vs. VEH; p < 0.01). Diameters of DOM or SUB were not affected by immunization or treatment. Concentrations of IGF-I and IGFBP-3 (determined by ligand blot analysis) in FFL from both DOM and SUB were lower (p < 0.05) in GRFi than in HSAi cows. In contrast, IGFBP-2 in FFL was elevated in SUB, but not DOM, in GRFi compared to HSAi cows.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗

PubMed1985

Prolactin and TSH responses to both domperidone and TRH in normal and hyperprolactinaemic women after dopamine synthesis blockade.

A study of the effect of alpha-methyl-1-tryosine (metyrosine) blockade (2 g/d for 2 d) of dopamine (DA) synthesis on the PRL and TSH response to domperidone (DOM) and TRH in normal women and subjects with pathological hyperprolactinaemia is reported. In the normal subjects, there was a marked increase in basal PRL (51.7 +/- 11.1 vs 5.7 +/- 1.0 ng/ml) and the PRL and TSH responses to DOM were abolished. The PRL response to TRH was also reduced. In the hyperprolactinaemic subjects, metyrosine had no effect on basal PRL nor on the virtually non-existent PRL response to DOM, whereas it abolished the exaggerated TSH response. The conclusion is drawn that the response of both PRL and TSH to DA receptor blockers is really dependent upon DA inhibitory tone. A fall in this tone can also be postulated as responsible for the hyporesponsiveness of PRL to DOM frequently observed in pathological hyperprolactinaemia. In addition, the fact that metyrosine also abolished the exaggerated TSH response to DOM shows that the latter is totally dependent on enhanced DA inhibition of the thyrotrophs. Lastly, the reduced PRL response to TRH after metyrosine indicates that DA partly determines the ability of the lactotrophs to respond to TRH.

Adult↗

PubMed2004

Inadequate carbohydrate intake following prolonged exercise does not increase muscle soreness after 15 minutes of downhill running.

In Delayed Onset Muscle Soreness (DOMS), muscles become sore 24 to 48 hours after eccentric and unaccustomed activity. Fiber stiffness, due to decreased muscle glycogen, may predispose muscle to greater damage during eccentric exercise. This study sought to determine if inadequate carbohydrate intake following a protocol to decrease muscle glycogen would increase DOMS after 15 min of downhill running. Thirty-three male subjects (age, 18-35 years) were randomized into 3 groups for testing over a 7-day period. The depletion (DEP) group (n= 12) underwent a glycogen depletion protocol prior to a 15-min downhill run designed to induce DOMS. The repletion (FED) group (n = 10) underwent a glycogen depletion protocol followed by a carbohydrate repletion protocol (>80% CHO) prior to downhill running. The third (ECC) group (n = 11) performed only the downhill running protocol. Subjective muscle soreness, isometric force production, relaxed knee angle, and thigh circumference were measured pretreatment and on days 1, 2, 3, 4, and 6 post treatment. Subjective muscle soreness for all groups increased from 0 cm pretreatment to 3.05 +/- 0.72 cm (on a 10-cm scale) on day 1 post treatment (p<.05). All groups were significantly different from baseline measurements until day 4 post treatment. Each group experienced a decline in isometric force from 281 +/- 45 N pre- to 253 +/- 13 N on day 1 post treatment (p <.05). The decrease in isometric force persisted in all groups for 4 days post treatment. Increases in thigh circumference and relaxed knee angle elevations in all 3 groups were statistically different (p <.05) from pretreatment until day 4. No differences were noted between groups for any of the parameters examined. In the current study, 15 min of downhill running is sufficient to cause DOMS with the associated functional and morphological changes; however, inadequate carbohydrate intake after a glycogen depleting exercise does not appear to exacerbate DOMS and the associated symptoms.

Adolescent↗

PubMed2001

Production of refractory dissolved organic matter by bacteria.

Most of the oceanic reservoir of dissolved organic matter (DOM) is of marine origin and is resistant to microbial oxidation, but little is known about the mechanisms of its formation. In a laboratory study, natural assemblages of marine bacteria rapidly (in <48 hours) utilized labile compounds (glucose, glutamate) and produced refractory DOM that persisted for more than a year. Only 10 to 15% of the bacterially derived DOM was identified as hydrolyzable amino acids and sugars, a feature consistent with marine DOM. These results suggest that microbial processes alter the molecular structure of DOM, making it resistant to further degradation and thereby preserving fixed carbon in the ocean.

Amino Acids↗

PubMed1998

Distribution and life strategies of two bacterial populations in a eutrophic lake

Monoclonal antibodies and epifluorescence microscopy were used to determine the depth distribution of two indigenous bacterial populations in the stratified Lake Plusssee and characterize their life strategies. Populations of Comamonas acidovorans PX54 showed a depth distribution with maximum abundances in the oxic epilimnion, whereas Aeromonas hydrophila PU7718 showed a depth distribution with maximum abundances in the anoxic thermocline layer (metalimnion), i. e., in the water layer with the highest microbial activity. Resistance of PX54 to protist grazing and high metabolic versatility and growth rate of PU7718 were the most important life strategy traits for explaining the depth distribution of the two bacterial populations. Maximum abundance of PX54 was 16,000 cells per ml, and maximum abundance of PU7718 was 20,000 cells per ml. Determination of bacterial productivity in dilution cultures with different-size fractions of dissolved organic matter (DOM) from lake water indicates that low-molecular-weight (LMW) DOM is less bioreactive than total DOM (TDOM). The abundance and growth rate of PU7718 were highest in the TDOM fractions, whereas those of PX54 were highest in the LMW DOM fraction, demonstrating that PX54 can grow well on the less bioreactive DOM fraction. We estimated that 13 to 24% of the entire bacterial community and 14% of PU7718 were removed by viral lysis, whereas no significant effect of viral lysis on PX54 could be detected. Growth rates of PX54 (0.11 to 0.13 h-1) were higher than those of the entire bacterial community (0.04 to 0.08 h-1) but lower than those of PU7718 (0.26 to 0.31 h-1). In undiluted cultures, the growth rates were significantly lower, pointing to density effects such as resource limitation or antibiosis, and the effects were stronger for PU7718 and the entire bacterial community than for PX54. Life strategy characterizations based on data from literature and this study revealed that the fast-growing and metabolically versatile A. hydrophila PU7718 is an r-strategist or opportunistic population in Lake Plusssee, whereas the grazing-resistant C. acidovorans PX54 is rather a K-strategist or equilibrium population.

Journal Article↗

PubMed2005

Seasonal response of stream biofilm communities to dissolved organic matter and nutrient enrichments.

Dissolved organic matter (DOM) and inorganic nutrients may affect microbial communities in streams, but little is known about the impact of these factors on specific taxa within bacterial assemblages in biofilms. In this study, nutrient diffusing artificial substrates were used to examine bacterial responses to DOM (i.e., glucose, leaf leachate, and algal exudates) and inorganic nutrients (nitrate and phosphate singly and in combination). Artificial substrates were deployed for five seasons, from summer 2002 to summer 2003, in a northeastern Ohio stream. Differences were observed in the responses of bacterial taxa examined to various DOM and inorganic nutrient treatments, and the response patterns varied seasonally, indicating that resources that limit the bacterial communities change over time. Overall, the greatest responses were to labile, low-molecular-weight DOM (i.e., glucose) at times when chlorophyll a concentrations were low due to scouring during significant storm events. Different types of DOM and inorganic nutrients induced various responses among bacterial taxa in the biofilms examined, and these responses would not have been apparent if they were examined at the community level or if seasonal changes were not taken into account.

Biofilms↗

PubMed2005

Biomass production and assimilation of dissolved organic matter by SAR11 bacteria in the Northwest Atlantic Ocean.

Members of the SAR11 clade often dominate the composition of marine microbial communities, yet their contribution to biomass production and the flux of dissolved organic matter (DOM) is unclear. In addition, little is known about the specific components of the DOM pool utilized by SAR11 bacteria. To better understand the role of SAR11 bacteria in the flux of DOM, we examined the assimilation of leucine (a measure of biomass production), as well as free amino acids, protein, and glucose, by SAR11 bacteria in the Northwest Atlantic Ocean. We found that when SAR11 bacteria were >25% of total prokaryotes, they accounted for about 30 to 50% of leucine incorporation, suggesting that SAR11 bacteria were major contributors to bacterial biomass production and the DOM flux. Specific growth rates of SAR11 bacteria either equaled or exceeded growth rates for the total prokaryotic community. In addition, SAR11 bacteria were typically responsible for a greater portion of amino acid assimilation (34 to 61%) and glucose assimilation (45 to 57%) than of protein assimilation (< or = 34%). These data suggest that SAR11 bacteria do not utilize various components of the DOM pool equally and may be more important to the flux of low-molecular-weight monomers than to that of high-molecular-weight polymers.

Alphaproteobacteria↗

PubMed1984

Isolation and characterization of Bordetella pertussis phenotype variants capable of growing on nutrient agar: comparison with phases III and IV.

Unsupplemented nutrient agar (NA) was used to select spontaneous phenotype variants (PVs) of Bordetella pertussis Tohama I and 3779 which, by their growth on NA, could possibly be considered equivalent to phase IV in the system of Leslie and Gardner (P.H. Leslie and A.D. Gardner, J. Hyg. 31:423-434, 1931) or phase III in the system of Kasuga et al. (T. Kasuga, Y. Nakase, K. Ukishima, and K. Takatsu, Kitasato Arch. Exp. Med. 26:121-134, 1953). NA growers (Gna+) were selected from the flat, nonhemolytic, non-NA grower (Dom- Hly- Gna-) PV of both strains at a rate of between 10(-7) to 10(-8) per cell per generation. When cultured on Bordet-Gengou agar (BGA), more than one colony type was observed in strain 3779; these all retained the Gna+ characteristic during 10 to 30 passages on BGA. Analysis of 125I-surface-labeled whole cells by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed no major changes between the Dom- Hly- Gna+ PV and their Dom- Hly- Gna- PV parents in polypeptide profile (by Coomassie stain), in surface exposure of proteins (by autoradiography), or in lipopolysaccharide profile (by silver stain). Increased resistance to oleic acid, tetracycline, erythromycin, rifampin, and penicillin G, however, was characteristic for the Dom- Hly- Gna+ PV. Five phase IV strains and a phase III B. pertussis strain had similar antibiotic and oleic acid sensitivity profiles as the Dom- Hly- Gna+ isolates and plated with similar efficiency on NA, despite heterogeneity in BGA colonial morphology and lipopolysaccharide profile.

Agar↗

PubMed2006

Influence of dissolved organic matter and inorganic nutrients on the biofilm bacterial community on artificial substrates in a northeastern Ohio, USA, stream.

Stream bacteria may be influenced by the composition and availability of dissolved organic matter (DOM) and inorganic nutrients, but knowledge about how individual phylogenetic groups in biofilm are affected is still limited. In this study, the influence of DOM and inorganic nutrients on stream biofilm bacteria was examined. Biofilms were developed on artificial substrates (unglazed ceramic tiles) for 21 days in a northeastern Ohio (USA) stream for five consecutive seasons. Then, the developed biofilm assemblages were exposed, in the laboratory, to DOM (glucose, leaf leachate, and algal exudates) and inorganic nutrients (nitrate, phosphate, and nitrate and phosphate in combination) amendments for 6 days. Bacterial numbers in the biofilms were generally higher in response to the DOM treatments than to the inorganic nutrient treatments. There were also apparent seasonal variations in the response patterns of the individual bacterial taxa to the nutrient treatments; an indication that limiting resources to bacteria in stream biofilms may change over time. Overall, in contrast to the other treatments, bacterial abundance was generally highest in response to the low-molecular-weight DOM (i.e., glucose) treatment. These results further suggest that there are interactions among the different bacterial groups in biofilms that are impacted by the associated nutrient dynamics among seasons in stream ecosystems.

Bacteria↗

PubMed1989

Integumental nutrient uptake by aquatic organisms.

Integumental nutrient transport is a widespread characteristic of soft-bodied marine invertebrates. These processes, which are qualitatively similar to the Na-dependent transporters of intestinal epithelia, have kinetic and energetic characteristics that make them particularly well suited for accumulating materials from the extremely low substrate concentrations found in seawater. Despite the low concentrations of DOM in natural waters, rates of DOM uptake are large and clearly capable of supporting a significant fraction of the metabolic needs of some species. Indeed, recent studies with larval invertebrates suggest that integumental uptake of DOM may play a pivotal role in animal nutrition. Current and future studies on the mechanism and regulation of these processes, on the metabolic fate of accumulated DOM, and on the distribution of DOM in natural waters, promise to resolve the remaining issues on the role of integumental transport in the nutrition of aquatic organisms.

Adaptation, Physiological↗

PubMed1996

Hospital charges for stroke patients.

BACKGROUND AND PURPOSE: Stroke is a common disease with a yearly cost in the United States of approximately $30 billion. The increasing prevalence of managed care and cost-containment measures may affect the delivery of stroke care now and in the future. This study was performed to determine (1) hospital charges and test utilization for stroke patients and (2) the effectiveness of educational efforts in modifying test utilization and related hospital charges. METHODS: Patients with a diagnosis of stroke who were discharged from either the neurology service or another service of the Department of Medicine (DOM) were identified. Data on test utilization and hospital charges were collected and analyzed. Following this analysis, educational sessions were held in an effort to reduce the use of specific diagnostic tests. The effectiveness of these methods was studied in a second group of stroke patients. RESULTS: In the baseline period there were 303 stroke patients, of which 262 (86%) were discharged from the neurology service and 41 (14%) were discharged from other services of the DOM. Patients on the neurology service had a lower mean length of stay than patients on the other services of the DOM (9.2 days versus 10.5 days) and lower mean total charges per case ($13,149 versus $15,727), although the respective differences were not statistically significant. Patient on the neurology service were more likely to have both brain CT and MRI performed (82 of 262 patients, 31.3%) than patients on the other services of the DOM (4 of 41, 9.8%, P = .005). In addition, patients on the neurology service were more likely to undergo a transthoracic echocardiogram than patients on the other services of the DOM (71.8% versus 53.7%, P = .025). After educational sessions, the percentage of stroke patients on the neurology service having both CT and MRI fell from 31.3% to 17.7% (P = .005), and the number of stroke patients having a transthoracic echocardiogram fell from 71.8% to 60.3% (P = .025). However, the overall charges for stroke patients on the neurology services did not decrease. CONCLUSIONS: Education can be successful in reducing the utilization of and associated charges for specific diagnostic tests for some stroke patients. A multidisciplinary approach to case management, using tools such as care maps, may be necessary to realize significant cost savings in certain groups of stroke patients.

Aged↗

PubMed1990

Interactions of dopaminergic and peptidergic factors in the control of prolactin release.

Oxytocin (OT) has been shown to play a role in the control of physiological PRL release and has been demonstrated to have a direct effect on the pituitary to stimulate PRL secretion. Administration of OT into the third ventricle, however, lowers PRL levels. This reduction could be mediated by either an inhibition of the release of endogenous OT into the hypohysial portal circulation or via an alteration in the release of some other PRL releasing (PRF) or PRL release-inhibiting (PIF) factor. In order to determine if centrally administered OT lowers PRL levels by increasing secretion of dopamine (DA) into the portal circulation, endogenous dopaminergic tone was blocked by injection of the DA antagonist domperidone (DOM). Subcutaneous administration of DOM resulted in elevated PRL levels which could be further augmented by iv infusion of OT (at 0.01 or 0.1 microgram OT/kg.min) or partially, but significantly, reduced by pretreatment with anti-OT antiserum (0.75 ml) indicating that under conditions of DA blockade, OT (which has little PRF activity during conditions of normal dopaminergic tone) can stimulate PRL secretion by a direct pituitary action. Treatment with DOM did not prevent, however, the reduction in PRL levels produced by central administration of OT (2 micrograms). This suggests that the effect of OT to alter PRL secretion when administered into the third ventricle was not mediated via an increase in DA release into the portal circulation. Furthermore, central administration of the OT antagonist CAV-259 (1-deamino-2-D-Trp-4-Val-8-Orn-OT) after DOM treatment resulted in a significant increase in PRL secretion indicating that endogenous levels of OT within the hypothalamus inhibit PRL secretion through a nondopaminergic mechanism. This stimulatory effect of the OT antagonist was not blocked by pretreatment with anti-OT antiserum (iv) which had been demonstrated previously to reduce the PRL surges in lactating mothers and steroid-primed ovariectomized rats, as well as to block the increase in PRL secretion seen after central administration of vasoactive intestinal peptide (VIP). Thus the central effect of OT to alter PRL secretion was probably not due to a change in the release of OT into the portal circulation. Intravenous administration of a VIP antagonist (D-4-Cl-6-Phe-17-Leu-VIP, previously demonstrated to be capable of reducing the PRL surge seen in lactating mothers) into DOM-treated rats does not alter PRL levels but blocks the ability of central administration of the OT antagonist CAV-259 to increase PRL levels under these conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1983

Defective regulation of prolactin secretion after successful removal of prolactinomas.

The PRL response to nomifensine (Nom), an indirect DA agonist; domperidone (Dom), a DA receptor antagonist; and TRH, which directly stimulates the PRL-secreting cells, was evaluated 2-53 months after surgery in 13 patients in whom successful removal of a prolactinoma had resulted in normal serum PRL levels and return of regular menses or libido and potency. In addition, the pattern of TSH secretion in response to Dom and the spontaneous rise in plasma PRL of 6 cured patients during pregnancy were evaluated. Nom induced an inconsistent decrease in basal PRL levels, a pattern contrasting with that in healthy women in whom plasma PRL was markedly suppressed after administration of the drug. Dom and TRH elicited a significant rise of basal PRL levels, but the rise was markedly lower than that occurring in the control group. The TSH increment after Dom treatment was lower than that before surgery, though higher than that in the controls. Evaluation of individual patients showed that only one patient had a normal PRL response to either Nom or Dom, while the TSH response to the latter returned to normal in five of seven patients. During pregnancy, plasma PRL rose inconsistently in the patients, and PRL levels were generally lower than those in normal pregnant women. These results suggest the presence of an abnormality in the dopaminergic mechanism(s) of PRL control before and after adenomectomy or, less likely, the existence of impaired pituitary function or reserve.

Adenoma↗

PubMed2003

Effects of delayed onset muscle soreness on selected physiological responses to submaximal running.

This study examined the effects of delayed-onset muscle soreness (DOMS) on selected physiological responses to submaximal exercise. Seven male and four female subjects (Ss) aged 21-37 years completed two submaximal running sessions at an individualized pace corresponding to a blood lactate concentration (bLa) of approximately 2.5 mmol x L(-1). Following the first session (T1), Ss performed a series of lower extremity resistance exercises designed to induce DOMS. Subjects were then retested (T2) 24-30 hours later, during which time all Ss experienced DOMS. Oxygen uptake, heart rate (HR), respiratory exchange ratio, rating of perceived exertion (RPE), and bLa were measured every 6 minutes. Significant trial effects (p < 0.05) were observed for HR and RPE. HR was significantly higher during T1 at minutes 6 and 12 (p < 0.05), and RPE values were significantly higher at T2 during all recording periods (p < 0.05). Results from this study suggest that DOMS does not affect submaximal oxygen uptake. However, DOMS does appear to affect one's perception of effort.

Adult↗