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Biomedical subjects

J Sleep

Publications and source records attributed to J Sleep.

At least 37 records · Page 2Linked to original sources
PubMed1992

Research and the practice of midwifery.

During the past decade, the professional journals have contained numerous papers authored by nurses and nurse-researchers describing the gap which persists between research and clinical practice. Problems have been highlighted and challenges explored in the quest to discover ways of encouraging practitioners to become more aware of research evidence as a knowledge base for practice. Many of the identified issues may be transposed into a midwifery setting but other factors may be recognized which are specific to the practice of midwifery. This paper considers both conceptual and pragmatic issues in an attempt to explore the complexity of the influences which may affect the integration of research into midwifery practice.

Attitude of Health Personnel↗
PubMed1992

A randomized controlled trial to compare three types of fetal scalp electrode.

OBJECTIVES: To compare three scalp electrodes in respect of need for reapplication, trace quality and scalp trauma. DESIGN: Randomized controlled trial. SETTING: Maternity Unit, Royal Berkshire Hospital, Reading. PARTICIPANTS: 780 women in labour at term, with cephalic fetal presentation, deemed to require electronic fetal heart rate monitoring using a scalp electrode. INTERVENTIONS: Three types of fetal scalp electrode: Rocket-Rolon (double-helix spiral); Hewlett-Packard (double-helix spiral); and Surgicraft-Copeland (clip). MAIN OUTCOME MEASURES: Need for more than one electrode; reason for replacement; trace quality; scalp trauma; direct financial costs. RESULTS: Reapplication was significantly least likely in the Surgicraft-Copeland group (odds ratio vs Hewlett-Packard = 0.61, 95% CI 0.41-0.90; odds ratio vs Rocket-Rolon = 0.43, 95% CI = 0.29-0.62). This reflected a much lower rate of replacement because of detachment. The Hewlett-Packard was, however, least likely to be replaced because of poor trace quality. Interpretable traces were equally common, but trace quality tended to be superior in the Hewlett-Packard group. There was no serious scalp trauma. Difficulty removing the electrode was least often reported in the Hewlett-Packard group, and a mark on the scalp persisted least often in the Rocket-Rolon group. CONCLUSIONS: The Surgicraft-Copeland performed the best overall, and particularly in respect of attachment to the scalp. It appears to be the electrode of choice of the three tested.

Adult↗
PubMed1991

Nurse Education Tomorrow Conference 1990. The what and how of teaching research.

Within the last decade nurse educators have been required to introduce research into the curriculum of every pre- and post-registration programme. This has lead to a debate concerning what practitioners need to know about research and about the best way to teach the research component of any educational programme. Two main approaches may be identified: facilitating research awareness and learning research by 'doing'. Both approaches raise a number of logistical and ethical problems. Certain of these problems are compounded by the large numbers of nurses who may be required to undertake a research project as a course component. Moreover, the absence of research evidence about the most effective means of educating nurses to become discerning consumers of research leaves the teacher without a sound framework to guide educational practice. In the light of recent educational reforms, this paper considers the unprecedented opportunities for nurse and midwife teachers to explore the role of research in the curriculum and in teaching.

Attitude of Health Personnel↗
PubMed1989

Ultrasound and pulsed electromagnetic energy treatment for perineal trauma. A randomized placebo-controlled trial.

Ultrasound and pulsed electromagnetic energy therapies are increasingly used for perineal trauma sustained during childbirth. The study included 414 women with moderate or severe perineal trauma randomly allocated to receive active ultrasound, or active pulsed electromagnetic energy, or corresponding placebo therapies; the allocation was double-blind for each machine. Overall, more than 90% thought that treatment made their problem better. There were no clear differences between the groups in outcome either immediately after treatment, or 10 days or 3 months postpartum, other than more pain associated with pulsed electromagnetic energy treatment at 10 days. Bruising looked more extensive after ultrasound therapy but then seemed to resolve more quickly. Neither therapy had an effect on perineal oedema or haemorrhoids. The place of these new therapies in postnatal care should be clarified by further controlled trials before they become part of routine care.

Adult↗
PubMed1988

Demembranated muscle fibers catalyze a more rapid exchange between phosphate and adenosine triphosphate than actomyosin subfragment 1.

The rate of ATP in equilibrium with Pi exchange, that is, the incorporation of medium Pi into ATP during the net hydrolysis of ATP, has been measured for rabbit psoas muscle fibers, myofibrils, and actomyosin subfragment 1 (acto-S1). The maximum exchange rate in fibers at saturating [Pi] is 0.04 s-1 per myosin head at 8 degrees C, pH 7, and an ionic strength of 0.2 M. The dependence of the rate on Pi concentration can be approximated by a hyperbola with an apparent dissociation constant (Km) of 3 mM. Myofibrils catalyze ATP in equilibrium with Pi exchange with a similar Km but at a slightly lower rate. In contrast, the soluble acto-S1 system, in which ATP hydrolysis is not coupled to tension generation, catalyzes exchange at a rate 500 times lower than that of fibers at low Pi concentration, and the Km for Pi is greater than 50 mM. The difference between the ATP in equilibrium with Pi exchange of fibers and of acto-S1 is discussed in terms of a model in which Pi binds to a force-generating state AM'-ADP and, due to mechanical constraint, the average free energy of this state is higher in the fiber than in acto-S1.

Adenosine Triphosphate↗
PubMed1987

West Berkshire perineal management trial: three year follow up.

Women who had participated in a randomised controlled trial of policies of restricted (10%) versus liberal (51%) episiotomy during spontaneous vaginal delivery were recontacted by postal questionnaire three years after delivery. Altogether 674 out of 1000 responded, and there was no evidence of a differential response rate between the two trial groups. Similar numbers of women in the two groups reported further deliveries, almost all of which had been vaginal and spontaneous. Fewer women allocated to restrictive use of episiotomy required perineal suturing after subsequent delivery, but this difference was not significant. Pain during sexual intercourse and incontinence of urine were equally reported in the two groups. The similarity in incontinence rates persisted when severity, type of incontinence, and subsequent deliveries were taken into account. Liberal use of episiotomy does not seem to prevent urinary incontinence or increase long term dyspareunia.

Adult↗
PubMed1987

Activation of myosin ATPase by actin isolated from cultured BHK cells and the effect of gelsolin.

Activation of skeletal muscle myosin and myosin subfragment-1 (S1) by actin purified from the cytoplasm of cultured BHK cells was studied using the fluorescence of pyrene-labelled BHK F-actin and its quenching by S1 and by an enzyme-linked ATPase assay. At non-saturating concentrations, both muscle and BHK actin activated skeletal muscle myosin to the same degree: at 30 degrees C and an ionic strength of 108 mM, 1 microM actin approximately doubled the ATPase of myosin or of S1. The association between BHK actin and S1 was also followed in a fluorescence stop flow: the rate of ATP binding monitored by the loss of light scattering upon dissociation of actin was again the same for BHK and muscle actin. The similarity of activation of myosin ATPase by BHK and muscle actin at low actin concentrations (i.e. the similarity of Vmax/Km) suggests that both Vmax and Km are similar for the two types of actin. The effect of varying filament length on actin activation of myosin ATPase was examined using pig plasma or BHK gelsolin to regulate the length. For both types of actin, maximum enhancement of the actomyosin ATPase activity was observed at an actin/gelsolin ratio of about 30:1, whereas inhibition was observed at lower ratios. Both activation and inhibition of actomyosin ATPase were apparent in the absence or presence of calcium; differences were observed only in the extent and the time course of the effect.

Actins↗
PubMed1986

Inhibition of myofibrillar and actomyosin subfragment 1 adenosinetriphosphatase by adenosine 5'-diphosphate, pyrophosphate, and adenyl-5'-yl imidodiphosphate.

Adenosine 5'-diphosphate (ADP), inorganic pyrophosphate (PPi), and adenyl-5'-yl imidodiphosphate (AMPPNP) act as competitive inhibitors of the ATPase of myofibrils and actomyosin subfragment 1 (acto-S1). At I = 0.2 M, pH 7, and 15 degrees C, the inhibition constants for rabbit myofibrils are 0.17, 3, and 5 mM, respectively; the values for frog myofibrils at 0 degrees C are very similar, being 0.22, 1.5, and 2.5 mM. The inhibition constant of AMPPNP is about 2 orders of magnitude larger than the reported dissociation constant for fibers [Marston, S. B., Rodger, C. D., & Tregear, R. T. (1976) J. Mol. Biol. 104, 263-276]. A possible reason for this difference is that AMPPNP binding results in the dissociation of one head of each myosin molecule. The inhibition constants for rabbit acto-S1 cross-linked with 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide measured under the same conditions were 0.12, 2.6, and 3.5 mM for ADP, PPi, and AMPPNP, respectively. The inhibition of cross-linked and native acto-S1 was compared at low ionic strength and was found to be similar. The value for ADP is very similar to reported values of the dissociation constant whereas the inhibition constants for AMPPNP and PPi are an order of magnitude weaker [Greene, L. E., & Eisenberg, E. (1980) J. Biol. Chem. 255, 543-548].

Adenosine Diphosphate↗
PubMed1986

A randomized comparison of glycerol-impregnated chromic catgut with untreated chromic catgut for the repair of perineal trauma.

Glycerol-impregnated chromic catgut and untreated chromic catgut were compared in a randomized controlled trial involving 737 consecutive women who required repair of perineal trauma following spontaneous vaginal delivery. Medical staff preference was equally divided between the two materials. More untreated chromic catgut sutures required removal both by 10 days and by 3 months postpartum. Women whose perineal trauma was repaired with glycerol-impregnated chromic catgut were 10% more likely to have perineal pain at 10 days and 33% more likely to suffer from dyspareunia in the 3 months following delivery. The high rates of maternal morbidity associated with glycerol-impregnated chromic catgut appear to preclude its use for perineal repair.

Catgut↗
PubMed1985

Dependence of adenosine triphosphatase activity of rabbit psoas muscle fibres and myofibrils on substrate concentration.

The rate of hydrolysis of adenosine triphosphate (ATP) by chemically skinned rabbit muscle fibres was measured as a function of Mg ATP concentration in the range 5 microM to 5 mM. Pyruvate kinase and lactate dehydrogenase were used to link adenosine diphosphate formation to oxidation of nicotinamide adenine dinucleotide which was followed by the change in absorption at 340 nm. The ATPase rate of a fully activated fibre (pCa = 4.5) increased monotonically with Mg ATP concentration in a manner that could be readily fitted by a hyperbola. At 15 degrees C, pH 7 and an ionic strength of 0.2 M the rate at saturating Mg ATP (Vm) was 1.78 +/- 0.2 s-1 per myosin head (mean +/- S.D.; n = 6) and the Mg ATP concentration needed for half the maximal rate (Km) was 16.6 +/- 2 microM. The ATPase of fibres that had been stabilized by cross-linking with 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide (EDC) was also investigated. Cross-linking did not significantly affect the Vm or Km and these fibres proved useful for investigating the adequacy of the pyruvate kinase activity for regenerating hydrolysed ATP. Myofibrils were cross-linked with EDC or glutaraldehyde to prevent shortening. Their ATPase properties were investigated: the values of Vm were 0.85 +/- 0.18 (mean +/- S.D.; n = 14) and 0.82 +/- 0.05 s-1 (n = 6) and of Km were 18.0 +/- 2.8 and 12.4 +/- 2.4 microM respectively. The values of Vm and Km for EDC cross-linked myofibrils were fairly insensitive to ionic strength, the Km decreasing 40% and the Vm increasing 50% for a change from 0.2 to 0.3 M. This slight dependence on ionic strength is considered in relation to the ionic strength dependence of the elementary rate constants of the actomyosin subfragment-1 ATPase cycle.

Adenosine Triphosphatases↗
PubMed1984

West Berkshire perineal management trial.

One thousand women were allocated at random to one of two perineal management policies, both intended to minimise trauma during spontaneous vaginal delivery. In one the aim was to restrict episiotomy to fetal indications; in the other the operation was to be used more liberally to prevent perineal tears. The resultant episiotomy rates were 10% and 51% respectively. An intact perineum was more common among those allocated to the restrictive policy. This group experienced more perineal and labial tears, however, and included four of the five cases of severe trauma. There were no significant differences between the two groups either in neonatal state or in maternal pain and urinary symptoms 10 days and three months post partum. Women allocated to the restrictive policy were more likely to have resumed sexual intercourse within a month after delivery. These findings provide little support either for liberal use of episiotomy or for claims that reduced use of the operation decreases postpartum morbidity.

Adult↗