Effect of oxytocin on the pattern of electromyographic activity in the oviduct and uterus of the ewe around oestrus

1992 ◽  
Vol 4 (2) ◽  
pp. 193 ◽  
Author(s):  
CL Gilbert ◽  
PJ Cripps ◽  
DC Wathes
Keyword(s):  
Reproductive Tract ◽  
Muscular Activity ◽  
High Amplitude ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Free Standing ◽  
Late Luteal Phase ◽  
Before And After ◽  
First Time

This study tested the hypothesis that the administration of oxytocin in doses equivalent to endogenous concentrations at and around oestrus could affect uterine and oviductal muscular activity at the time of gamete transport. Four ewes were fitted with recording electrodes in the left ampulla, ampullary-isthmic junction, utero-tubal junction and uterine horn. After surgical recovery, recordings from conscious free-standing animals were made for up to 10 h per day from Day -3 to Day +3 relative to oestrus in each ewe. Daily blood samples were taken for progesterone radioimmunoassay, and a vasectomized ram used to assess oestrus. A range of physiological doses of oxytocin (10-100 mU), or control saline injections were given intravenously. Electromyographic (EMG) activity was measured before and after injections. Spontaneous activity throughout the reproductive tract was low on Day -3 but increased to peak at oestrus (P < 0.05), when the pattern of activity consisted of short (2-10 s) co-ordinated high amplitude bursts (2-5 min-1). After oestrus, as overall activity declined, longer episodes of activity appeared but these occurred with a much slower frequency (1-4 h-1). Responsiveness to oxytocin was greatest on the day of oestrus at all electrode sites. Elevated responsiveness (relative to Day -3, the late luteal phase) was seen from Day -1 to Day +2 at the ampullary-isthmic junction and uterus, but on the day of oestrus only at the ampulla and utero-tubal junction. Duration of increased EMG activity after oxytocin injection ranged from 5 to 20 min. These results show for the first time that the uterine and oviductal musculatures of the ewe in vivo reached a peak in sensitivity to physiological concentrations of oxytocin at oestrus. When combined with information on oxytocin receptor populations and endogenous circulating concentrations, this suggest that endogenous oxytocin could influence oviduct and myometrial activity at this time.

Bone Elastometric Measurements by Ultrasound Reflectometry: Observations on Physiology and Functional Organization of Bone

2000 ◽  
Author(s):  
Shreefal S. Mehta ◽  
Peter P. Antich ◽  
Billy Smith ◽  
Matthew A. Lewis ◽  
Edmond Richer
Keyword(s):  
Mechanical Properties ◽  
Functional Organization ◽  
Muscular Activity ◽  
Diagnostic Techniques ◽  
Rate Of Change ◽  
Activity Levels ◽  
Bone Material ◽  
Clinical Observations ◽  
First Time

Abstract Bone mechanical properties are strongly dependent on orientation and optimally adapted to the directional stresses induced by load bearing and muscular activity. Spatial and directional homogeneity and a slow rate of change of material mechanical properties are commonly assumed in the literature. The assumptions are based on limitations of widespread diagnostic techniques but are contradicted by results from several established techniques, including ultrasound reflectometry. A device based on the ultrasound reflectometry technique measures the mechanical elasticity of bone noninvasively at multiple sites and orientations, making it possible to carry out longitudinal studies at any chosen location in vivo. In vivo elastometric measurements over the length of a tibia were obtained with this device, demonstrating quantitatively for the first time the spatial and directional heterogeneity of bone material properties in vivo. Clinical observations made on two subjects also suggest that bone does exhibit rapid changes in response to altered activity levels.

Overestimation of Bispectral Index in Sedated Intensive Care Unit Patients Revealed by Administration of Muscle Relaxant

2003 ◽  
Vol 99 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Benoît Vivien ◽  
Sophie Di Maria ◽  
Alexandre Ouattara ◽  
Olivier Langeron ◽  
Pierre Coriat ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Neuromuscular Blockade ◽  
Bispectral Index ◽  
Muscle Relaxant ◽  
Muscular Activity ◽  
Electromyographic Activity ◽  
Adductor Pollicis Muscle ◽  
Number Of Patients ◽  
Before And After

Background Electromyographic activity has previously been reported to elevate the Bispectral Index (BIS) in patients not receiving neuromuscular blockade while under sedation in the intensive care unit. This study aimed to investigate the magnitude of the decrease of BIS following administration of muscle relaxant in sedated intensive care unit patients. Methods The authors prospectively investigated 45 patients who were continuously sedated with midazolam and sufentanil to achieve a Sedation-Agitation Scale value equal to 1 and who required administration of muscle relaxant. BIS (BIS version 2.10), electromyography, and acceleromyography at the adductor pollicis muscle were recorded simultaneously before and after neuromuscular blockade. Sixteen of these 45 patients were also studied simultaneously with the new BIS XP. Results After administration of a muscle relaxant, BIS (67 +/- 19 vs. 43 +/- 10, P &lt; 0.001) and electromyographic activity (37 +/- 9 vs. 27 +/- 3 dB, P &lt; 0.001) significantly decreased. Multiple regression analysis showed that the decrease of BIS following administration of myorelaxant was significantly correlated to BIS and electromyographic baseline values. Using standard BIS range guidelines, the number of patients under light or deep sedation versus general anesthesia or deep hypnotic state was markedly overestimated before administration of myorelaxant (53 vs. 2%, P &lt; 0.001). Conclusions The BIS in sedated intensive care unit patients may be lower with paralysis for an equivalent degree of sedation because of high muscular activity. The magnitude of BIS overestimation is significantly correlated to both BIS and electromyographic activity before neuromuscular blockade. The authors conclude that clinicians who determine the amount of sedation in intensive care unit patients only from BIS monitoring may expose them to unnecessary oversedation.

scholarly journals Electromyographic activity of the vastus medialis and gastrocnemius implicates a slow stretch-shortening cycle during rowing in the field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Steffen Held ◽  
Tobias Siebert ◽  
Lars Donath
Keyword(s):  
Performance Enhancement ◽  
Muscular Activity ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Vastus Medialis ◽  
Leg Muscles ◽  
Rowing Performance ◽  
Specific Muscle ◽  
Two Phases ◽  
Activation Phase

Abstract The consideration of the temporal and electromyographic (EMG) characteristics of stretch-shortening cycles (SSC) are crucial for the conceptualization of discipline-specific testing and training. Since leg muscles are first stretched (eccentric) and then contracted (concentric) during rowing, it can be assumed that the entire muscle tendon complex performs a SSC. Thus, it should be elucidated whether the rowing cycle can be attributed to either a slow or fast SSC. Therefore, EMG of the vastus medialis and gastrocnemius were captured (n = 10, 22.8 ± 3.1 years, 190 ± 6 cm, 82.1 ± 9.8 kg) during (single scull) rowing and subsequently compared to typical slow (countermovement jump, CMJ) and fast (drop jump, DJ) SSCs. The elapsed time between the EMG onset and the start of the eccentric phase was monitored. The pre-activation phase (PRE, before the start of the eccentric phase) and the reflex-induced activation phase (RIA 30–120 ms after the start of the eccentric phase) have been classified. Notable muscular activity was observed during DJ before the start of the eccentric phase (PRE) as well as during RIA. In contrast, neither CMJ nor rowing revealed any EMG-activity in these two phases. Interestingly, CMJ and race-specific rowing showed an EMG-onset during the eccentric phase. We conclude that rowing is more attributable to a slow SSC and implies that fast SSC does not reflect discipline specific muscle action and could hamper rowing-performance-enhancement.

In vivo perspective study about the effects of weekly low dose administration of zoledronic acid (ZA) on angiogenesis

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 3558-3558
Author(s):  
D. Santini ◽  
B. Vincenzi ◽  
F. Battistoni ◽  
S. Galluzzo ◽  
L. Rocci ◽  
...  
Keyword(s):  
Zoledronic Acid ◽  
Cancer Patients ◽  
Serum Levels ◽  
Vascular Endothelial ◽  
Low Doses ◽  
Dose Administration ◽  
Before And After ◽  
Endothelial Growth Factor ◽  
First Time

3558 Purpose: Recent data have demonstrated in preclinical tumor models an antiangiogenic and antitumor activity of low weekly doses of ZA. As a consequence, the purpose of this study was to confirm these data, evaluating in cancer patients the modifications in angiogenic cytokines levels following repeated weekly low doses of ZA. Experimental Design: 26 consecutive cancer patients with bone metastases treated, for the first time, with four weekly doses of 1 mg of ZA followed by standard doses (4 mg every 28 days) were prospectively evaluated for circulating levels of vascular endothelial growth factor (VEGF) at different time points: just before and after 1, 7, 14, 21, 28, 56 and 84 days following the first disphosphonate infusion. Results: Basal serum VEGF median levels were significantly decreased just after 7 days (-29.7%) (with only one weekly infusion) (P=0.038), This significant decrease of circulating VEGF levels persisted 14(-33.2%), 21 (-39.4%), 28(-31.8%), 56(-33.6%) and 84(-27.9%) days after the first infusion (respectively, P=0.002, P=0.001, P=0.008, P=0.002, P=0.014). Conclusions: This study confirms, for the first time in humans, that weekly low doses of zoledronic acid could have antiangiogenic properties through a significant and long lasting decrease of VEGF serum levels. No significant financial relationships to disclose.

scholarly journals Uterine progesterone signaling is a target for metformin therapy in PCOS-like rats

2018 ◽  
Vol 237 (2) ◽  
pp. 123-137 ◽  
Author(s):  
Min Hu ◽  
Yuehui Zhang ◽  
Jiaxing Feng ◽  
Xue Xu ◽  
Jiao Zhang ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Target Genes ◽  
Polycystic Ovary ◽  
Metformin Therapy ◽  
Before And After ◽  
Elevated Expression ◽  
Targeted Gene Expression ◽  
First Time

Impaired progesterone (P4) signaling is linked to endometrial dysfunction and infertility in women with polycystic ovary syndrome (PCOS). Here, we report for the first time that elevated expression of progesterone receptor (PGR) isoforms A and B parallels increased estrogen receptor (ER) expression in PCOS-like rat uteri. The aberrant PGR-targeted gene expression in PCOS-like rats before and after implantation overlaps with dysregulated expression of Fkbp52 and Ncoa2, two genes that contribute to the development of uterine P4 resistance. In vivo and in vitro studies of the effects of metformin on the regulation of the uterine P4 signaling pathway under PCOS conditions showed that metformin directly inhibits the expression of PGR and ER along with the regulation of several genes that are targeted dependently or independently of PGR-mediated uterine implantation. Functionally, metformin treatment corrected the abnormal expression of cell-specific PGR and ER and some PGR-target genes in PCOS-like rats with implantation. Additionally, we documented how metformin contributes to the regulation of the PGR-associated MAPK/ERK/p38 signaling pathway in the PCOS-like rat uterus. Our data provide novel insights into how metformin therapy regulates uterine P4 signaling molecules under PCOS conditions.

scholarly journals Uterine progesterone signaling is a target for metformin therapy in PCOS-like rats

2017 ◽  
Author(s):  
Min Hu ◽  
Yuehui Zhang ◽  
Jiaxing Feng ◽  
Xue Xu ◽  
Jiao Zhang ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Target Genes ◽  
Polycystic Ovary ◽  
Metformin Therapy ◽  
Before And After ◽  
Elevated Expression ◽  
Targeted Gene Expression ◽  
First Time

AbstractImpaired progesterone (P4) signaling is linked to endometrial dysfunction and infertility in women with polycystic ovary syndrome (PCOS). Here we report for the first time that elevated expression of progesterone receptor (PGR) isoforms A and B parallels increased estrogen receptor (ER) expression in PCOS-like rat uteri. The aberrant PGR-targeted gene expression in PCOS-like rats before and after implantation overlaps with dysregulated expression of Fkbp52 and Ncoa2, two genes that contribute to the development of uterine P4 resistance. In vivo and in vitro studies of the effects of metformin on the regulation of the uterine P4 signaling pathway under PCOS conditions showed that metformin directly inhibits the expression of PGR and ER along with the regulation of several genes that are targeted dependently or independently of PGR-mediated uterine implantation. Functionally, metformin treatment corrected the abnormal expression of cell-specific PGR and ER and some PGR-target genes in PCOS-like rats with implantation. Additionally, we documented how metformin contributes to the regulation of the PGR-associated MAPK/ERK/p38 signaling pathway in the PCOS-like rat uterus. Our data provide novel insights into how metformin therapy regulates uterine P4 signaling molecules under PCOS conditions.

Actions of oxytocin and vasopressin on oestrogen-induced electromyographic activity recorded from the uterus and oviduct of anoestrous ewes

1994 ◽  
Vol 6 (2) ◽  
pp. 203 ◽  
Author(s):  
VJ Ayad ◽  
CL Gilbert ◽  
SA McGoff ◽  
EL Matthews ◽  
DC Wathes
Keyword(s):  
Binding Sites ◽  
Jugular Vein ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
High Affinity ◽  
Oestradiol Treatment ◽  
Cardiovascular Side Effects ◽  
Oxytocin Receptors ◽  
Order Of Magnitude

Oxytocin and the related peptide [Arg8]vasopressin (AVP) have previously been shown to bind with equally high affinity to oxytocin binding-sites (presumed oxytocin receptors) present within the uterus and oviduct of oestrous ewes. There is a possibility, therefore, that AVP mediates oxytocic actions through these binding sites. For the present study, ewes in seasonal anoestrus were treated with oestradiol-17 beta (50 micrograms subcutaneously, daily for 2-4 days). It was shown initially that this treatment stimulated the development of high-affinity oxytocin binding-sites (Kd 4.4 +/- 0.8 nmol L-1) which had similar affinity for AVP (Kd 4.2 +/- 0.9 nmol L-1) in the myometrium. The efficacy of oxytocin and AVP in vivo were compared by recording electromyographic (EMG) activity from the ampullary-isthmic junction of the left oviduct and the left uterine horn of four conscious ewes. Before oestradiol treatment there was no EMG response to oxytocin even at supraphysiological (1000 mU) doses. During oestradiol treatment, EMG activity was consistently increased in response to injections of 25 mU and 100 mU oxytocin via the jugular vein, but not to saline or 100 mU AVP. Higher doses of AVP were not investigated because of the possibility of cardiovascular side effects. A subsequent blood sampling experiment showed that maximal concentrations of oxytocin and AVP (achieved in peripheral plasma during the first 2 min following injection into the jugular vein) were of a similar order of magnitude after injection of equivalent doses of the two peptides. It is concluded that AVP probably does not mediate biological activity through the oxytocin receptor in non-pregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Component Permeabilities and Water Contents in periplaneta Integument: Role Of The Epidermis Re-Examined

1985 ◽  
Vol 117 (1) ◽  
pp. 155-169 ◽  
Author(s):  
J. MACHIN ◽  
G. J. LAMPERT ◽  
M. J. O'DONNELL
Keyword(s):  
In Vitro Techniques ◽  
Linear Relationships ◽  
Before And After ◽  
Pressure Lowering ◽  
First Time ◽  
Water Contents

Improved in vivo and in vitro techniques for measuring cuticular water permeability are described. Air flowing over a cuticle disc mounted in a holder, permitted elimination of unstirred layers, or corrections for them, for the first time. Conditions inside the holder were incompatible with the long-term health of the epidermal cells. Significantly, mean permeabilities of these discs did not differ from values obtained in vivo on the same cuticular plate. Overall cuticular permeability was apportioned between endocuticle and combined epicuticle and exocuticle on the basis of measurements made before and after solvent extraction of lipids. Under identical activity gradients, endocuticle permeability was 35 to 40 times greater than the value for the other layer. Permeability of both component layers showed strongly non-linear relationships with ambient activity, with empirical proportionality to the reciprocal of vapour pressure lowering. Cuticle water contents measured in activity gradient conditions showed significantly higher values in vivo than in vitro. The amount of water contained in the combined epicuticle and exocuticle was too small to measure. We conclude that neither permeability nor water content data support the existence of a significant water barrier in the region of the epidermis.

scholarly journals Influence of artificial insemination time period relative to ovulation on fertility of mares

2016 ◽  
Vol 18 (2) ◽  
Author(s):  
A. V. Tkachev ◽  
V. I. Sheremeta ◽  
O. L. Tkacheva
Keyword(s):  
Artificial Insemination ◽  
Reproductive Tract ◽  
Optimal Time ◽  
Dominant Follicle ◽  
Horse Breed ◽  
Time Period ◽  
Before And After ◽  
The Impact ◽  
First Time

The results of the study of the effect of artificial insemination of horses by the cooled and thawed semen which was prepared by Kharkiv technology depending on the time of the dominant follicle ovulation using the atraumatic tool developed for insemination of mares have been presented in the article. In modern practice of artificial insemination of horses, there are two opposing views on the timing of insemination of mares (before or after ovulation) so we decided to investigate the impact of this factor on sperm, obtained, chilled and kriokonse–rvovana for Kharkiv technology. The time of semen administration into the reproductive tract of mares depending on the ovulation of the dominant follicle is the least investigated factor that effects the efficiency of mare insemination. The artificial insemination of the horses by the semen that was prepared by Kharkiv technology with the use of the atraumatic instrument developed by us for artificial insemination of mares depending on the time of ovulation of the dominant follicle was conducted for the first time. It has been stated that the optimal time for the insemination of mares by the cooled or thawed semen of stallions depending on the ovulation with the use of the atraumatic instrument developed by us is the time period for 4 hours before and after ovulation. When insemination of mares Ukrainian horse breed tools we have and the sperm that chilled by Kharkivtion technology for 4 hours before and after ovulation received about the same output foals. When artificial insemination Ukrainian horse breed mares we developed noninvasive device after 4 or more hours of ovulation foals output decreased by 50.77% (P < 0.01) compared with insemination to ovulation and the 50.12% (P < 0.01) compared with insemination after ovulation. When artificial insemination of mares Ukrainian horse breed tools we have and sperm cryopreserved for that Kharkov Technologies for 4 hours after ovulation received incredibly more foals out at 3.47% compared with insemination before ovulation. When artificial insemination of mares Ukrainian horse breed developed our noninvasive device after 4 or more hours of ovulation foals output decreased by 35.23% (P < 0.01) compared with insemination to ovulation and the 38.70% (P < 0,01) compared to the insemination after ovulation. When carrying out the artificial insemination of the mares of Ukrainian horse breed for more than 4 hours after the ovulation the fertility decreased by 50,12 – 50.77% (P < 0.01) and by 35,23 – 38,70% (P < 0.01) by  cooled and thawed semen, respectively.

A comparison of treadmill locomotion in adult cats before and after spinal transection

1996 ◽  
Vol 76 (1) ◽  
pp. 471-491 ◽  
Author(s):  
M. Belanger ◽  
T. Drew ◽  
J. Provencher ◽  
S. Rossignol
Keyword(s):  
Muscular Activity ◽  
Swing Phase ◽  
Cycle Duration ◽  
Electromyographic Activity ◽  
Step Cycle ◽  
Initial Portion ◽  
Emg Amplitude ◽  
Flexor Muscles ◽  
Before And After ◽  
Treadmill Locomotion

1. The aim of this study was to document the kinematics and the electromyographic activity recorded from several muscles during treadmill locomotion in the same cat (N = 4), before and after spinalization by using a chronic implantation method. Because identical experimental and control conditions were used, it was possible to establish similarities and differences in the timing and amplitude of the muscular activity and kinematics under the intact and spinal conditions in the same animal. The data presented in this paper were collected when the cats had fully recuperated a stable locomotor pattern, walking at a constant speed of approximately 0.4 m/s. 2. The adult spinal cats retained many of the general locomotor features and electromyographic (EMG) characteristics seen before transection. However, there were also important differences. 3. There was a reduction in the step length that was principally due to the forward placement of the paw at the onset of the stance. Similarly, there was a decrease in the step cycle duration which was attributed to a reduction of both the stance and swing phases. 4. The overall angular excursions of the hip, knee, and ankle were generally similar, although joints were sometimes more flexed at all phases of the step cycle. In contrast, the overall excursions of the metatarsophalangeal joints was much greater in all four cats after spinalization due to a paw drag during the initial portion of the swing phase that exaggerated the plantarflexion. 5. There was an increase in the EMG amplitude of the flexor muscles at two of three joints (i.e., hip, knee, and ankle) in each cat after spinalization. The change in the EMG amplitude of the extensors did not appear to be as consistent as that observed in the flexor muscles. When looking at each cat individually, the postspinalization extensor activity decreased at two of three joints in two cats, whereas the opposite was true for the other two cats. 6. There was a delay in the onset of the knee flexor (semitendinosus) activity while the ankle dorsiflexor (tibialis anterior) activity started earlier with respect to the beginning of the swing phase. The onset of hip flexors was somewhat more variable. This change in the timing of flexor activity was most probably responsible for the paw drag at the onset of the swing phase. 7. The present results reveal that despite the few differences, the spinal cord and the hindlimbs afferents are capable of generating very good locomotor patterns with almost normal kinematics and EMG characteristics.

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