Expulsion Phase Research Articles

Decolonizing the 1862 Death Marches

In November of 1862 approximately 2,10o Dakota men, women, and children were forcibly moved in two groups from the Lower Sioux Agency to concentration camps at either Fort Snelling or Mankato, events which marked the first phase of expulsion of our Dakota people from our homeland of Minisota Makoce (Land Where the Waters Reflect the Skies).' These two groups were paying the severest of penalties for the retributive actions of Dakota people who dared to fight the Wasicu (white) invaders, who dared to fight because they could not take any more offenses, who dared to fight because they were pushed to desperation and there appeared to be no other options. This article will examine existing accounts regarding these removals from a critical perspective within the broader framework of colonialism. Furthermore, it will discuss the necessity of truth telling and remembering in our commemoration of the removals to the achievement of healing and restoration of well-being among Dakota people. When examined within a framework of colonization, the U.S.-Dakota War of 1862 is just one point on a continuum that carries through to the present day, but it also provides a possibility of change for the future. At the most basic level it challenges the narrative that seeks to justify policies of invasion, forced removal, and genocide. In doing so the narrative immediately shifts from one of white innocence and Dakota guilt to one of white oppression and Dakota subjugation. On the topic of violence and oppression, Brazilian liberationist educator Paulo Freire wrote:

The role of oxytocin in parturition

Oxytocin and the oxytocin receptor have two important roles in labour. Evidence in all mammalian species suggests that neurohypophysical oxytocin plays a role in the expulsive phase and, although there are less supporting data, a role for oxytocin in the initiation of labour is likely. The initiation of labour may be mediated in women and rhesus monkeys by paracrine rather than endocrine mechanisms. Although initial characterisation of the oxytocin knockout mouse suggested that oxytocin is not important in this species, subsequent investigations have demonstrated that oxytocin is important for the precise timing of the onset of labour. Studies in knockout mice also confirm important interrelationships between oxytocin and prostaglandins. Oxytocin stimulates prostaglandin release in many species, mainly in the decidua/uterine epithelium. The effects of oxytocin are mediated by tissue‐specific oxytocin receptor expression, which leads directly to contraction in the myometrium and prostaglandin formation in the decidua. There is a dramatic increase in oxytocin receptor expression in these tissues in late pregnancy and pharmacological inhibition delays delivery, which suggests that, in contrast to oxytocin, the oxytocin receptor is essential for normal labour.

The role of oxytocin in parturition

Oxytocin and the oxytocin receptor have two important roles in labour. Evidence in all mammalian species suggests that neurohypophysical oxytocin plays a role in the expulsive phase and, although there are less supporting data, a role for oxytocin in the initiation of labour is likely. The initiation of labour may be mediated in women and rhesus monkeys by paracrine rather than endocrine mechanisms. Although initial characterisation of the oxytocin knockout mouse suggested that oxytocin is not important in this species, subsequent investigations have demonstrated that oxytocin is important for the precise timing of the onset of labour. Studies in knockout mice also confirm important interrelationships between oxytocin and prostaglandins. Oxytocin stimulates prostaglandin release in many species, mainly in the decidua/uterine epithelium. The effects of oxytocin are mediated by tissue-specific oxytocin receptor expression, which leads directly to contraction in the myometrium and prostaglandin formation in the decidua. There is a dramatic increase in oxytocin receptor expression in these tissues in late pregnancy and pharmacological inhibition delays delivery, which suggests that, in contrast to oxytocin, the oxytocin receptor is essential for normal labour.

FRANK STARLING MECHANISM ON ALTERNATING PUMP VENTRICULAR MODELS

An alternating pump system simulating the left ventricle in a mechanical cardio-vascular model, has been modified to show Frank Starling regulating mechanism. An inextensible thin plastic wall chamber has been put around the syringe's core and connected to the internal syringe's chamber by two lateral holes. During the filling and the expulsion phases the external chamber changes his volume and the net output depends on the filling pressure. The regulating mechanism shows a beat to beat response and the dependence of systolic aortic pressure, systolic ventricular work, stroke output with respect ventricular filling pressure show a "physiological" behavior. This solution will be introduced in the mechanical whole model to study the changes of aorto-ventricular interaction by changing aortic compliance.

Korrelation zwischen sonographischen und klinischen Befunden in der Plazentarperiode - Lösungszeiten, Lösungszeichen und Lösungsmodus

Objective: We analyzed the duration and phases of the third stage of labor with gray-scale and color Doppler sonography. We also compared ultrasound findings with the clinical signs of placental separation and the mode of placental delivery. Methods: The third stage of labor was recorded by color Doppler sonography in 57 patients after vaginal delivery. Results: The third stage of labor can be broken down into three distinct phases. The latent phase consists of the interval between delivery of the newborn and beginning placental separation (median duration 141 sec, range 5 - 790 sec). The beginning of this phase was marked by cessation of blood flow between the myometrium and the placenta. The detachment phase is characterized by shearing off of the placenta from the myometrium (median duration 50 sec, range 15-100 sec). The expulsion phase begins with completed separation and ends with the vaginal delivery of the placenta (median 80.5 sec, range 2-385 sec). Kustner's sign (absent umbilical cord retraction on suprapubic pressure) was positive and Schroder's sign (fundal elevation) in 98% of women with sonographically separated placentae. Clinically, placental separation by the Schultze mechanism was present in 45 cases (79%). In contrast, sonography showed that placental separation began from the inferior pole of the placenta without retroplacental hematoma in all cases. Conclusion: The third stage of labor consists of three distinct phases. The duration of the third stage is determined mainly by the latent phase, in which blood flow between the myometrium and the placenta ceases. Clinical and sonographic signs of placental separation correlate closely. The lower part of the placenta usually separates first, so that the mechanism described by Schultze is only of theoretical interest.

Savaging gilts are more restless and more responsive to piglets during the expulsive phase of parturition

Piglet-directed aggression by farrowing pigs seriously threatens the welfare of the piglets and also results in economic waste within the pig industry. Pre-weaning piglet mortality in the UK is around 11% with savaging accounting for up to 25% of deaths. The aim of this study was to investigate whether gilts that savage piglets behave differently to non-savaging gilts during the expulsive phase of parturition. The behaviour of the gilts during the 8 h following the birth of the first piglet was recorded. The gilts were categorised as savagers ( n=4) or non-savagers ( n=15) depending on their response to piglets during farrowing, and then behaviour during farrowing was compared between the two groups. The maternal behaviour during the first 8 h of farrowing differed significantly between the savagers and non-savagers. Savaging gilts were significantly more restless and more responsive towards their piglets during farrowing as characterised by increased posture changing, higher frequency of walking and time spent investigating piglets that approached their head. Overall the results of this study suggest that aberrant maternal behaviour during farrowing involves increased restlessness and responsiveness to piglets, particularly in the early stages of the expulsive phase, which are opposite to the inactivity and passivity suggested to reflect good maternal care in the pig. It is suggested that this restlessness and responsiveness of savaging gilts may not necessarily reflect poor maternal ability, but may be related to the individual’s inability to cope with restrictive environments around farrowing.

Effect of manually assisted cough and mechanical insufflation on cough flow of normal subjects, patients with chronic obstructive pulmonary disease (COPD), and patients with respiratory muscle weakness

BACKGROUNDIt has been suggested that cough effectiveness can be improved by assisted techniques. The effects of manually assisted cough and mechanical insufflation on cough flow physiology are reported in this...

Effect of manually assisted cough and mechanical insufflation on cough flow of normal subjects, patients with chronic obstructive pulmonary disease (COPD), and patients with respiratory muscle weakness

BACKGROUNDIt has been suggested that cough effectiveness can be improved by assisted techniques. The effects of manually assisted cough and mechanical insufflation on cough flow physiology are reported in this study.METHODSThe physiological actions and patient self-assessment of manually assisted cough and mechanical insufflation were investigated in 29 subjects (nine normal subjects, eight patients with chronic obstructive pulmonary disease (COPD), four subjects with respiratory muscle weakness (RMW) with scoliosis, and eight subjects with RMW without scoliosis).RESULTSThe peak cough expiratory flow rate and cough expiratory volume were not improved by manually assisted cough and mechanical insufflation alone or in combination in normal subjects. The median increase in peak cough expiratory flow in subjects with RMW without scoliosis with manually assisted cough alone or in combination with mechanical insufflation of 84 l/min (95% confidence interval (CI) 19 to 122) and 144 l/min (95% CI 14 to 195), respectively, reflects improvement in the expulsive phase of coughing by these techniques. Manually assisted cough and mechanical insufflation in combination raised peak expiratory flow rate more than either technique alone in this group. The abnormal chest shape in scoliotic subjects and the fixed inspiratory pressure used made effective manually assisted cough and mechanical insufflation difficult in this group and no improvements were found. In patients with COPD manually assisted cough alone and in combination with mechanical insufflation decreased peak expiratory flow rate by 144 l/min (95% CI 25 to 259) and 135 l/min (95% CI 30 to 312), respectively.CONCLUSIONSManually assisted cough and mechanical insufflation should be considered to assist expectoration of secretions in patients with RMW without scoliosis but not in those with scoliosis.

Clozapine inhibits micturition parameters and the external urethral sphincter during cystometry in anesthetized rats

Clozapine therapy has been associated with a high degree of urinary disturbances. The purpose of this study is to examine the effect of clozapine on urodynamic parameters and on the activity of the external urethral sphincter in anesthetized rats. Single cystometrograms (CMG) were performed on urethane-anesthetized female Sprague–Dawley rats, while also recording the EMG from the external urethral sphincter. Clozapine (0, 0.1, 1, 10 mg/kg) was administered intravenously. In addition, the peripheral end of the pudendal nerve was stimulated in order to determine if clozapine was exerting peripheral effects directly on the external urethral sphincter. Clozapine increased the bladder capacity while reducing the micturition volume thus resulting in a marked increase in the residual volume. The pressure threshold was increased but the peak pressure during contraction remained unchanged. The expulsion time and contraction time were decreased and the amplitude of the high frequency oscillations (HFO) seen during the expulsion phase were markedly reduced and even abolished. The EMG from the external urethral sphincter also showed marked decreases after clozapine, and the bursting pattern seen during HFO was abolished. Clozapine had no effect on the activity elicited from electrical stimulation of the pudendal nerve. Clozapine inhibits several urodynamic parameters and inhibits the activity of the external urethral sphincter in anesthetized rats. These effects may help explain the urinary disturbances reported in the clinical literature.

Assessment of aspiration risk in stroke patients with quantification of voluntary cough.

Dysphagia and subsequent aspiration are serious complications of acute stroke that may be related to an impaired cough reflex. It was hypothesized that aspirating stroke patients would have impaired objective measures of voluntary cough as compared with both nonstroke control subjects and nonaspirating stroke patients. Swallowing was evaluated by standard radiologic or endoscopic methods, and stroke patients were grouped by aspiration severity (severe, n = 11; mild, n = 17; no aspiration, n = 15). Airflow patterns and sound pressure level (SPL) of voluntary cough were measured in stroke patients and in a group of normal control subjects (n = 18). Initial stroke severity was determined retrospectively with the Canadian Neurological Scale. All cough measures were altered in stroke patients as a group relative to nonstroke control subjects. Univariate analysis showed that peak flow of the inspiration phase (770.6 +/- 80.6 versus 1,120.1 +/- 148.4 mL/s), SPL (90.0 +/- 3.1 versus 100.2 +/- 1.6 dB), peak flow of the expulsive phase (875.1 +/- 122.7 versus 1,884.1 +/- 221.6 mL/s), expulsive phase rise time (0.34 +/- 0.1 versus 0.09 +/- 0.01 s), and cough volume acceleration (5.5 +/- 1.3 versus 27.8 +/- 3.9 mL/s/s) were significantly impaired in severe aspirators as compared with nonaspirators. Aspirating patients had more severe strokes than nonaspirators (mean Canadian Neurological Scale score 7.7 +/- 0.7 versus 9.8 +/- 0.3). Multivariate logistic regression found only expulsive phase rise time values during cough correlated with aspiration status. Objective analysis of cough may provide a noninvasive way to identify the aspiration risk of stroke patients.

Effects of two atypical neuroleptics, olanzapine and risperidone, on the function of the urinary bladder and the external urethral sphincter in anesthetized rats

BackgroundA previous report showed that the atypical neuroleptic clozapine resulted in marked changes in urodynamic parameters and greatly inhibited the activity of the external urethral sphincter in anesthetized rats. Such findings may help explain the high incidence of urinary disturbances reported during clozapine therapy. In an effort to extend our observations to other atypical neuroleptic agents, the present study investigated the effects of two newer atypical antipsychotics, olanzapine and risperidone, on the bladder and external urethral sphincter during cystometry in anesthetized rats.ResultsAt a dose of 0.1 mg/kg (i.v.), olanzapine decreased the micturition volume and increased the residual volume. In addition, olanzapine decreased the expulsion time and the amplitude of the high frequency oscillations observed during the expulsion phase. Larger doses (1 mg/kg) had a greater effect. Olanzapine also reduced the activity recorded from the external urethral sphincter, and the bursting observed during the expulsion phase was abolished by 1.0 mg/kg. Risperidone had similar effects although the maximal effects were smaller than those observed with olanzapine. The amplitude of bladder contractions elicited by electrical stimulation of the pelvic nerve was reduced by olanzapine but not risperidone suggesting a possible anti-muscarinic peripheral effect of olanzapine.ConclusionsOlanzapine and risperidone significantly altered several voiding parameters and decreased the activity of the external urethral sphincter in the anesthetized rat. We propose that these effects are due to the central action of these drugs and not to peripheral effects. These findings may explain some of the clinical reports of urinary incontinence with risperidone and may predict similar occurrences with olanzapine therapy.

The effect of gas loss on the formation of bound stellar clusters

The effect of gas ejection on the structure and binding energy of newly formed stellar clusters is investigated. The star formation efficiency (SFE), necessary for forming a gravitationally bound stellar cluster, is determined. Two sets of numerical N-body simulations are presented: As a first simplified approach we treat the residual gas as an external potential. The gas expulsion is approximated by reducing the gas mass to zero on a given timescale, which is treated as a free parameter. In a second set of simulations we use smoothed particle hydrodynamics (SPH) to follow the dynamics of the outflowing residual gas self-consistently. We investigate cases where gas outflow is induced by an outwards propagating shock front and where the whole gas cloud is heated homogeneously, leading to ejection. If the stars are in virial equilibrium with the gaseous environment initially, bound clusters only form in regions where the local SFE is larger than 50% or where the gas expulsion timescale is long compared to the dynamical timescale. A small initial velocity dispersion of the stars leads to a compaction of the cluster during the expulsion phase and reduces the SFE needed to form bound clusters to less than 10%.

The effect of opioid antagonism and environmental restriction on plasma oxytocin and vasopressin concentrations in parturient gilts.

Oxytocin plays an important role at parturition due to its involvement in uterine contractions, foetal expulsion and the onset of maternal behaviour. The role of the related neurohypophysial hormone, vasopressin, is less clear; however, there is some evidence that it is also involved in maternal behaviour and its role in osmotic regulation is well established. The aim of this study was to investigate the inhibitory effects of endogenous opioids on these hormones during the expulsive phase of parturition in the pig, and to examine how opioid restraint interacts with environmental restriction. The subjects of this study were 31 Large Whitex Landrace primiparous sows (gilts). An indwelling jugular catheter was implanted under general anaesthesia at 12 days before the expected parturition day (EPD). From 5 days before the EPD 15 of the gilts were individually housed in a restrictive parturition crate without straw and 16 were individually housed in a straw-bedded pen. Blood samples were taken with increasing frequency towards and during parturition through a catheter extension to reduce disturbance. At 7.5 min after the birth of the first piglet half of the gilts in each environment received a dose of the opioid receptor antagonist naloxone (1 mg/kg, i.v.) with the remaining gilts receiving saline as a control. Overall, there was no effect of environment on either circulating oxytocin or vasopressin. However, both oxytocin and vasopressin were inhibited by endogenous opioids during the expulsive phase. The inhibitory effects of opioids on these hormones did not appear to have any adverse effects on the progress of parturition as judged by cumulative piglet birth intervals. The regulation of the opioid inhibition of oxytocin and vasopressin during parturition is discussed in relation to other neurotransmitters and whether opioid inhibition of these neurohypophysial hormones is part of the 'normal' physiological response to parturition or whether it is stress-induced.

Paleozoic Petroleum System of Central Saudi Arabia

ABSTRACT An integrated geochemical model was developed to reconstruct the history of expulsion, migration and entrapment of Paleozoic oil and gas in the main regional Permian Unayzah Sandstone Reservoir in Central Saudi Arabia. The model indicates that by the Late Jurassic, approximately 140 million years ago (Ma), the principal Paleozoic source rock, the Lower Silurian Qusaiba “hot” shale, was mature in the deepest hydrocarbon “kitchens”. Hydrocarbon expulsion started during the Aptian and Albian (late Early to early Middle Cretaceous, 100 to 120 Ma). Expulsion of oil and gas is linked to three geochemical events. Primary kerogen cracking led to a first episode of expulsion about 120 Ma. Secondary heavy component and oil cracking resulted in a second episode of expulsion at approximately 100 Ma. Between 20 to 10 Ma, later uplift, and the resulting pressure drop in the source rock, led to a third expulsion phase. The first two expulsion episodes were gradual, whereas the third was more rapid and related to uplift of the Arabian Arch, opening of the Red Sea and the Zagros Orogeny during the Miocene. Expulsion of oil nearly terminated after the Late Cretaceous, while gas continued to be expelled, though at a lower rate, in the Tertiary. Peak gas expulsion occurred post Early Eocene with significant gas generation from secondary cracking of oil retained in the source rock. Gas was sourced either directly from kerogen, or from secondary cracking of heavy absorbed components or non-migrated oils. The expulsion of gas coincides with oil expulsion for the first two episodes because the gas and oil formed as a single phase. As a result of Tertiary Uplift, gas separated from the oil and re-migrated in the final episode (20 to 10 Ma).

SEAL CAPACITY AND HYDROCARBON ACCUMULATION HISTORY IN DYNAMIC PETROLEUM SYSTEMS: THE EAST JAVA BASIN, INDONESIA AND THE TIMOR SEA REGION, AUSTRALIA

The East Java Basin, Indonesia, and the Timor Sea area and Yampi Shelf of the North West Shelf, Australia, are examples of dynamic petroleum systems where the processes of hydrocarbon generation, explusion, migration, accumulation and leakage are occurring today. Understanding the importance and relative balance of some or all these processes is a key step in reducing exploration uncertainty. In particular, seal effectiveness is a key factor controlling the prospectivity of traps within these petroleum systems.The seals in the East Java Basin are dynamic, rather than absolute, barriers to fluid flow. Empirical and experimental data from the largest producing gas field in the region, Pagerungan, suggest that it is a dynamically filling and leaking capillary trap, which may have been volumetrically larger at some time in the past.In the Timor Sea area, Neogene tectonism has caused both extensional faulting and basin formation. The faulting caused the partial to complete breaching of many of the traps in the region, whereas the subsidence in the newly created Neogene depocentres was the drive for a renewed phase of hydrocarbon expulsion and migration consisting principally of gas. In traps with high seal capacities, this charge of gas flushed preexisting oil accumulations. In other cases, completely breached traps were refilled with gas over periods as short as perhaps 2–3 My.On the Yampi Shelf, dry thermogenic gas is migrating actively across the shelf. Leakage rates to the sea floor are high, particularly as the regional seal thins against basement highs, and as the seal becomes thinner and sandier toward the margin. The risk of gas flushing of low-relief, oil-bearing traps in this area is ameliorated somewhat in a zone where seal capacity is low for gas (favouring gas leakage), but adequate for oil.

Two-phase responses of acid expulsion triggered by alpha-1a adrenoceptor in CHO cell

Using microphysiometer, we have investigated acid expulsion from CHO cells expressing human alpha-1a adrenoceptor. Time course of extracellular acidification rate after noradrenaline stimulation had two phases; one with a peak within 10 s reached several folds of base rate, and another increased gradually to two folds of base rate and reached plateau around two min. Both phases showed concentration-dependent increase of acidification rates in response to noradrenaline but had distinct pEC50 values; 6.0 for rapid phase and 6.6 for late phase. Amiloride and its analogs inhibited both phases entirely, suggesting that Na/H exchanger mainly mediated these acid expulsion responses. Elimination of Ca by BAPTA/EGTA treatment resulted in extensive reductions of the rapid phase response but small decrease of the late phase response. Several Ca channel blockers, Ni and LOE908 also suppressed the rapid phase while nifedipine, verapamil, SKF96365 and omega-conotoxin GIVA did not. Repeated stimulation with noradrenaline enhanced inhibitory effect of blockers. These results indicate that Ca is one of the elements in the rapid phase but not in the late phase of acid expulsion from CHO cells in response to alpha-1 adrenoceptor stimulation and suggest that Ca from both intracellular storage and some type of Ca channel dominantly participates in the rapid phase.

3H-spiperone binds with high affinity to a non-dopaminergic site on human B-lymphocytes, EBV transformed lymphoblasts and macrophages

In addition to serotonin, dopamine within the CNS is known to play a primary role in the control of ejaculation. However, whether D2 and/or D3 dopamine receptor subtypes mediate this effect is still unclear. In order to clarify this issue, a pharmacological competitive study using the preferential D3 agonist 7-hydroxy-2-(di-N-propylamino)tetralin (7-OH-DPAT) alone or in combination with competitive nonpreferential or preferential D2 and D3 antagonists delivered intracerebroventricularly (i.c.v.) was undertaken in anesthetized rats. Urethane-anesthetized male rats were implanted into the cerebral ventricle with a cannula for i.c.v. injections, and recording electrodes were placed within the bulbospongiosus (BS) muscle to monitor BS muscle contractions, which were used as a marker for the expulsion phase of ejaculation. Following i.c.v. injection, 7-OH-DPAT induced ejaculation and rhythmic BS muscle contractions. Co-injected i.c.v. with 7-OH-DPAT, the nonselective D2/D3 antagonist (raclopride), and the preferential D3 antagonist (S(−)-N[n-butyl-2-pyrrolidinyl)methyl]-1-methoxy-4-cyanonaphtalene-2-carboxamide; nafadotride) but not the preferential D2 antagonist ((±)-3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole; L 741,626) inhibited the occurrence of ejaculation and BS muscle contractions. These results suggest that i.c.v. delivery of 7-OH-DPAT does represent a pertinent model to investigate the physio-pharmacology of ejaculation. It is inferred that targeting brain D3 receptors may provide a therapeutic approach for treating ejaculatory disorders in humans.

Upper airway motor outputs during sneezing and coughing in decerebrate cats

The purposes of the present study were to determine which upper airway movements cause a difference in the expiratory airflow pathway between sneezing and coughing, and to develop a new animal model for studying the neural mechanism of sneezing in paralyzed animals, i.e. fictive sneezing. We compared the upper airway motor patterns of sneezing and coughing, induced by electrical stimulation of the anterior ethmoidal nerve (AEN) and superior laryngeal nerve, respectively, in non-paralyzed decerebrate cats. Respiratory and laryngeal motor patterns that consisted of an inspiration phase, compression phase, and expulsion phase were observed for both sneezing and coughing. The main difference was observed in the activity of the elevator of the back of the tongue, styloglossus (SG) muscle, which was explosively activated during the expulsion phase of sneezing, whereas it was virtually silent during coughing. The nasopharyngeal closers were weakly to moderately activated during sneezing. Their activities during coughing were weaker than during sneezing. Furthermore, the AEN-induced activities of the phrenic and abdominal nerves and the lateral branch of the hypoglossal nerve (lat-XII), which innervates the SG muscle, in paralyzed cats were consistent with the activities of the diaphragm, abdominal, and SG muscles during actual sneezing in non-paralyzed cats. Thus, we conclude that tongue movement is the main difference in the motor outputs between sneezing and coughing, which probably causes greater nasal airflow in sneezing, and that it is necessary to record the activity of the lat-XII to identify fictive sneezing in paralyzed cats.

Risk factors of inadequate pain relief during epidural analgesia for labour and delivery.

To determine the causes of failure of epidural analgesia during labour and delivery. During six months, pregnant patients receiving epidural analgesia and delivering vaginally were studied prospectively. Bupivacaine 0.125% was used for the initial bolus dose and subsequent continuous infusion. Top-ups of the same solution were used for inadequate pain relief assessed using a visual analogue pain score (VAPS) and/or by clinical examination. Inadequate pain relief was defined as the need for > or = 2 top-ups in addition to epidural infusion and failure during delivery as VAPS > or = 30 mm during the expulsion phase. 1009 patients delivered during this period, 596 had epidural analgesia for vaginal delivery of a live infant and data were complete in 456. Inadequate pain relief during labour and during delivery were found in 5.3% and 19.7% of patients. Risk factors of inadequate pain relief included: inadequate analgesic efficacy of the first dose (Odds ratio: 3.5, P = 0.001) and posterior presentation (Odds ratio: 5.6, P = 0.001). Radicular pain during epidural placement was associated with failure during labour (Odds ratio: 3.9, P = 0.05). Duration of epidural analgesia > six hours (Odds ratio: 9.1, P = 0.001) was a risk factor for insufficient pain relief during labour whereas duration of epidural analgesia < one hour was associated with pain during delivery (Odds ratio: 18.3, P = 0.001). Several obstetrical and epidural-related factors increase the risk of inadequate epidural analgesia. For some, simple changes of practice pattern may lead to improved pain relief.

Paracrine regulation of human placenta: control of hormonogenesis

There is much evidence indicating that the human placenta plays a very important role in modulating the endocrinology of pregnancy. Placental tissue produces cytokines, hormones and growth factors that are essential in the regulation of the feto-maternal unit. The production of these substances is regulated by a network of interactions within and between intra-uterine through paracrine and/or autocrine mechanisms. Communication between the gestational intra-uterine tissues is critical for successful pregnancy, from the earliest stage of implantation until the expulsive phase of delivery. This is confirmed by the demonstration that the human placenta directly controls the release of substances such as hCG, hPL, steroid hormones and prostoglandins. Furthermore, there is evidence that intra-uterine tissues also can regulate ACTH release and have effects on the hypothalamus–pituitary–gonadal axis and the hypothalamus–pituitary–adrenal axis. The set of data reported in this article confirms that the placenta must be considered an organ that is essential for the initiation, maintenance and successful conclusion of pregnancy and that an imbalance between the complex network of placental regulating systems may cause serious gestational disorders.