Time to get comfortable with a labour epidural.

Women frequently request regional analgesia during labour, yet little is known about how long it takes before they become comfortable. This prospective observational study aimed to determine various time-points following maternal request for regional analgesia in labour until comfort was achieved. It was conducted in two tertiary referral centres for maternity care in Australia between December 2009 and May 2010.Midwives and anaesthetists recorded times of maternal request for regional analgesia, anaesthetist contact,anaesthetist's arrival in the labour room, local anaesthetic infiltration on starting the procedure, injection of neuraxial local anaesthetic and first report of maternal comfort. Composite median times and interquartile range were recorded for maternal request to anaesthetist arrival, anaesthetist arrival to maternal comfort and total time from request to comfort. Statistical modelling and regression analyses assessed possible factors associated with these time intervals. A P value <0.05 was considered significant. Of the 324 maternal requests, 244 out of 324 (75.3%, 95% confidence interval 70.2% to 79.9%) were recorded as having achieved satisfactory labour analgesia. Median interquartile range times observed were: maternal request to anaesthetist arrival: 20 (10 to 35) minutes; anaesthetist arrival to maternal comfort: 40 (30 to 50) minutes; and total time from request to comfort: 65 (50 to 85) minutes. We have shown that approximately one hour is required for a mother to achieve comfort following her request for epidural analgesia during labour. Our findings are likely to provide useful information for antenatal education, enhance informed consent and improve the provision of anaesthetic services for labour analgesia.

NIMA-related kinase 2 (Nek2), a cell-cycle-regulated protein kinase localized to centrosomes, is complexed to protein phosphatase 1.

The cell cycle-regulated protein serine/threonine NIMA-related kinase 2 (Nek2), which shows a predominant localization at centrosomes, is identified as a protein which interacts with protein phosphatase 1 (PP1) using the yeast two-hybrid system. Complex formation between Nek2 and PP1 is supported by co-precipitation of the two proteins using transfected expression constructs of Nek2 and the endogenous Nek2/PP1 proteins. The sequence KVHF in the C-terminal region of Nek2, which conforms to the consensus PP1-binding motif, is shown to be essential for the interaction of Nek2 with PP1. Nek2 activity increases with autophosphorylation and addition of phosphatase inhibitors and decreases in the presence of PP1. PP1 is a substrate for Nek2 and phosphorylation of PP1gamma(1) on two C-terminal sites reduces its phosphatase activity. The presence of a ternary complex containing centrosomal Nek2-associated protein (C-Nap1), Nek2 and PP1 has also been demonstrated, and C-Nap1 is shown to be a substrate for both Nek2 and PP1 in vitro and in cell extracts. The implications of kinase-phosphatase complex formation involving Nek2 and PP1 are discussed in terms of the coordination of centrosome separation with cell cycle progression.

Protein phosphatase 1 interacts with p53BP2, a protein which binds to the tumour suppressor p53.

The p53 binding protein, termed p53BP2, was identified as a protein interacting with protein phosphatase 1 (PP1) in the yeast two hybrid system. The interaction was confirmed by co-immunoprecipitation of p53BP2 with epitope-tagged PP1 in vitro. The p53BP2-PP1 complex was stable to NaCl at concentrations which dissociate the p53-p53BP2 complex, and the binding of PP1 and p53 to p53BP2 was mutually exclusive. The region required for interaction with PP1 was shown to be contained within amino acids 297-431 of p53BP2, which includes two ankyrin repeats. The phosphorylase phosphatase activity of PP1 was inhibited by p53BP2 at nanomolar concentrations. These results suggest that PP1 may be involved in dephosphorylation and regulation of p53 through interaction with p53BP2.

A novel human protein serine/threonine phosphatase, which possesses four tetratricopeptide repeat motifs and localizes to the nucleus.

A novel human protein serine/threonine phosphatase, PP5, and a structurally related phosphatase in Saccharomyces cerevisiae, PPT1, have been identified from their cDNA and gene respectively. Their predicted molecular mass is 58 kDa and they comprise a C-terminal phosphatase catalytic domain and an N-terminal domain, which has four repeats of 34 amino acids, three of which are tandemly arranged. The phosphatase domain possesses all the invariant motifs of the PP1/PP2A/PP2B gene family, but is not closely related to any other known member (< or = 40% identity). Thus PP5 and PPT1 comprise a new subfamily. The repeats in the N-terminal domain are similar to the tetratricopeptide repeat (TPR) motifs which have been found in several proteins that are required for mitosis, transcription and RNA splicing. Bacterially expressed PP5 is able to dephosphorylate serine residues in proteins and is more sensitive than PP1 to the tumour promoter okadaic acid. A 2.3 kb mRNA encoding PP5 is present in all human tissues examined. Investigation of the intracellular distribution of PP5 by immunofluorescence, using two different antibodies raised against the TPR and phosphatase domains, localizes PP5 predominantly to the nucleus. This suggests that, like other nuclear TPR-containing proteins, it may play a role in the regulation of RNA biogenesis and/or mitosis.

Three genes for protein phosphatase 1 map to different human chromosomes: sequence, expression and gene localisation of protein serine/threonine phosphatase 1 beta (PPP1CB).

Complementary DNA encoding a catalytic subunit of protein phosphatase 1, termed PP1 beta, was isolated from a human teratocarcinoma library. Hybridisation with different cDNA fragments showed that all human tissues examined contained 3.1 kb, 4.0 kb and 5.4 kb PP1 beta mRNAs arising from alternative splicing of the 3' noncoding region. The level of the 5.4 kb mRNA relative to the 3.1 kb mRNA was higher in skeletal muscle than in other tissues and the PP1 beta/PP1 alpha mRNA ratio in rabbit tissues was highest in skeletal muscle. The 3' noncoding region of PP1 beta showed extreme conservation (> or = 90% identity) between man and rodents over 1.7 kb, suggesting that this region is of functional importance. The gene for human PP1 beta (PPP1CB) was localised to chromosome 2 by analysis of somatic cell hybrid DNA and mapped to band q23 by fluorescence in situ hybridization. These data show that the genes for three protein phosphatase catalytic subunits PP1 alpha, PP1 beta, PP1 gamma are all located on different chromosomes.

Sequence of human protein serine/threonine phosphatase 1 gamma and localization of the gene (PPP1CC) encoding it to chromosome bands 12q24.1-q24.2.

Complementary DNA encoding a catalytic subunit of protein phosphatase 1, termed PP1 gamma, was isolated from a human teratocarcinoma library. The sequence suggests that alternative splicing produces two forms of PP1 gamma, designated PP1 gamma 1 and PP1 gamma 2, which differ in their C-termini. The gene for human PP1 gamma (PPP1CC) was localized to chromosome 12 by analysis of somatic cell hybrid DNA and mapped to bands q24.1-q24.2 by in situ hybridisation. These data show that although PP1 gamma 1 and PP1 gamma 2 are 94% and 93% identical to PP1 alpha respectively, the PP1 gamma gene is not closely linked to the PP1 alpha gene, which has been mapped to chromosome 11.

Localization of the genes encoding the catalytic subunits of protein phosphatase 2A to human chromosome bands 5q23-->q31 and 8p12-->p11.2, respectively.

The gene for the alpha isoform of the catalytic subunit of human protein phosphatase 2A (PPP2CA) was localized to chromosome 5 using somatic cell hybrids, and then more finely mapped to chromosome region 5q23-->q31 by in situ hybridization using a tritiated cDNA probe. The gene for the beta isoform of the catalytic subunit of this enzyme (PPP2CB) was mapped by the polymerase chain reaction to human chromosome 8 using somatic cell hybrids. Fluorescence in situ hybridization was then used to localize the PPP2CB gene to 8p12-->p11.2, using a mixture of three genomic probes that ranged from 3.5 to 8 kb in size. Finally, Southern blot analysis of somatic cell hybrid DNA suggested that a PPP2CB catalytic subunit pseudogene (PPP2CBP) is on chromosome 16.

Identification of a third alternatively spliced cDNA encoding the catalytic subunit of protein phosphatase 2B beta.

Complementary DNA coding for a catalytic subunit of protein phosphatase 2B was isolated from a human teratocarcinoma library. It encodes a third isoform of protein phosphatase 2B beta, and differs from the cDNA for the second isoform by a deletion of 30 base pairs in the coding region. The deletion results in the loss of ten amino acids between the putative calmodulin site and a postulated autoinhibitory domain. An identical deletion occurs in one of the two alternatively spliced isoforms of PP2B alpha.

Protein phosphatase 1 activity in Drosophila mutants with abnormalities in mitosis and chromosome condensation.

A Drosophila gene encoding a protein phosphatase 1 (PP1) has been sequenced, and lethal mutations in this locus (87B) analysed. Two mutants (ck19e211 and ck19hs46), which disrupt mitosis, lack the 87B isoenzyme and express only approximately 20% of wild type PP1 activity. The promoter region of the gene is deleted in the ck19e211 mutant. A third mutant (ck19e078), which shows suppression of position effect variegation, but has little effect on mitosis, possesses approximately 35% of wild type PP1 activity. The results indicate that the PP1 87B isoenzyme is involved in regulation of chromosome condensation at interphase as well as mitosis.

Localization of the gene encoding a type I protein phosphatase catalytic subunit to human chromosome band 11q13.

A cDNA encoding one isoform (PP1 alpha) of the catalytic subunit of human protein phosphatase 1 has been isolated and used to map the human PP1 alpha gene (PPP1A) to chromosome band 11q13 by analysis of somatic cell hybrids and in situ hybridization. Neoplasms that map to 11q13 are discussed in the light of the recent findings that PP1 alpha is a putative tumor suppressor and that it plays a key role in the control of mitosis.

The major type-1 protein phosphatase catalytic subunits are the same gene products in rabbit skeletal muscle and rabbit liver.

The catalytic subunit of protein phosphatase-1 (PP1) isolated from rabbit liver had the same electrophoretic mobility as, and yielded peptide maps identical to those of the 33 kDa form of rabbit skeletal muscle PP1. The predicted amino-acid sequences of PP1 obtained from three rabbit liver cDNA clones were identical to that of PP1 alpha from rabbit skeletal muscle. These findings suggest that the distinctive substrate specificities and regulatory properties of hepatic and skeletal muscle type-1 protein phosphatases are not conferred by the catalytic subunits themselves, but by regulatory subunits that are complexed to the catalytic subunits in vivo.

Regulation of the absorption of dietary carbohydrate in man by two new glycosidase inhibitors.

Two new reversible inhibitors of intestinal alpha-glycosidases (BAY m1099 & o1248) have been derived from deoxynojirimycin. Their inhibitory substrate specificity has been investigated in man using test meals of the dietary carbohydrates, sucrose, maltose, and starch. Both inhibitors abolished the postprandial glycaemic rise after sucrose and m1099 50 mg did after maltose and starch, whereas o1248 20 mg had no effect after maltose and only a small effect after starch. Breath hydrogen evolution, as an indirect measure of malabsorption, showed that the reduced glycaemic responses, particularly after sucrose, were associated with considerable substrate malabsorption. Dose response studies showed that lower doses of both inhibitors could reduce postprandial glycaemia significantly without causing malabsorption. Both inhibitors were tolerated well. These two new enzyme inhibitors have different substrate specificity in man and can, in appropriate dose, regulate postprandial glycaemia by selective inhibition of brush border enzymes without causing malabsorption. In addition to their therapeutic importance, they provide a valuable experimental model of specific intestinal enzyme deficiency states.

Chromatographic analysis of sugars in physiological fluids by postcolumn reaction with cuprammonium: a new and highly sensitive method.

A new highly sensitive method of high-performance liquid chromatographic analysis has been used to separate mono-, di-, and oligosaccharides present in jejunal aspirates from experimentally perfused animals. The sugars in the column eluant are detected at 280 to 310 nm after reaction with cuprammonium. No reaction coil is required between the column and uv detector because the reaction is virtually instantaneous. This technique is more sensitive than differential refractometry, so that it is possible to detect 2.5 nmol (450 ng) of glucose routinely, compared to a minimum detection limit of 100 nmol (18 micrograms) using a commercial refractive index detector. Using a suitable postcolumn pump, the technique is not sensitive to changes in solvent composition, as with gradient elution, and is applicable to analysis of other cis-cis glycols.

Relationship between rate of digestion of foods and post-prandial glycaemia.

The amount of carbohydrate released at 1 and 5 h by digestion in vitro of 2 g carbohydrate portions of 14 foods by human digestive juices was compared with the area under the 2-h blood glucose response curve when 50 g carbohydrate portions were fed to groups of five to ten healthy volunteers. A significant relationship was found between the amounts of sugars and oligosaccharides liberated at 1 and 5 h and the food blood glucose area expressed as a percentage of the blood glucose area for 50 g glucose (r = 0.8627 and 0.8618, p less than 0.001). A significant relationship was also found between the glycaemic index and the food fibre content (p less than 0.02) and between the glycaemic index and the glucose trapping capacity of the foods (p less than 0.05). Legumes as a group liberated 56% less sugars and oligosaccharides (p less than 0.01) than the eight cereal foods over 5 h. It is suggested that such studies in vitro may help to identify food of use for diabetic patients, and at the same time throw further light on factors which affect post-prandial glycaemia.

Effect of acarbose on the 24-hour blood glucose profile and pattern of carbohydrate absorption.

Acarbose (Bay g 5421) is a powerful alpha-glucoside hydrolase inhibitor of potential value in the treatment of diabetes and hypoglycemic dumping syndrome after gastric surgery. The extent of its use may be limited by symptoms produced by carbohydrate malabsorption. To minimize these, the action of low doses of acarbose on 24-h blood glucose profiles and hydrogen evolution have been studied on four ambulant volunteers on control diets, after exclusion of sucrose and also after addition of guar in an attempt to enhance the therapeutic effect. Replacement of dietary sucrose by starch abolished significant hydrogen evolution in the morning after low doses of acarbose but did not reduce its effectiveness in decreasing the mean three-meal blood glucose area by 41% (P less than 0.002). Addition of hydrated guar to this diet reduced the mean three-meal glucose area after acarbose further by 72% (P less than 0.001) but increased hydrogen evolution. The results suggest that acarbose will be both effective and acceptable given at low dose when the dietary carbohydrate is starch.

Effect of guar crispbread with cereal products and leguminous seeds on blood glucose concentrations of diabetics.

To compare the effect on blood glucose concentrations of guar incorporated into crispbreads with that of unprocessed high-fibre foods groups of four to six diabetics took a total of seven test breakfasts on separate days. By comparison with a breakfast of wholemeal bread and cheese, guar crispbread combined with bread reduced the area under the glucose response curve to 51% (p < 0.05); bread and soya beans reduced the area to 65% (p < 0.05); guar crispbread with soya beans to 25% (p < 0.002); and soya beans with lentils to 29% (p < 0.002). Porridge and cornflake breakfasts showed no difference. The favourable results with leguminous seeds may not make such meals more acceptable than meals of guar products, but a combination of leguminous seeds and guar may allow smaller and more acceptable amounts of both to be used.