The key components of a successful model of midwifery-led continuity of carer, without continuity at birth: findings from a qualitative implementation evaluation.

BACKGROUND: Recent UK maternity policy changes recommend that a named midwife supports women throughout their pregnancy, birth and postnatal care. Whilst many studies report high levels of satisfaction amongst women receiving, and midwives providing, this level of continuity of carer, there are concerns some midwives may experience burnout and stress. In this study, we present a qualitative evaluation of the implementation of a midwife-led continuity of carer model that excluded continuity of carer at the birth. METHODS: Underpinned by the Conceptual Model for Implementation Fidelity, our evaluation explored the implementation, fidelity, reach and satisfaction of the continuity of carer model. Semi-structured interviews were undertaken with midwives (n = 7) and women (n = 15) from continuity of carer team. To enable comparisons between care approaches, midwives (n = 7) and women (n = 10) from standard approach teams were also interviewed. Interviews were recorded, transcribed and analysed using thematic analysis. RESULTS: For continuity of carer team midwives, manageable caseloads, extended appointment times, increased team stability, and flexible working patterns facilitated both care provided and midwives' job satisfaction. Both continuity of carer and standard approach midwives reported challenges in providing postnatal continuity given the unpredictable timing of labour and birth. Time constraints, inadequate staffing and lack of administrative support were reported as additional barriers to implementing continuity of carer within standard approach teams. Women reported continuity was integral to building trust with midwives, encouraged them to disclose mental health issues and increased their confidence in making birth choices. CONCLUSIONS: Our evaluation highlighted the successful implementation of a continuity of carer model for ante and postnatal care. Despite exclusion of the birth element in the model, both women and midwives expressed high levels of satisfaction in comparison to women and midwives within the standard approach. Implementation successes were largely due to structural and resource factors, particularly the combination of additional time and smaller caseloads of women. However, these resources are not widely available within the resources of maternity unit budgets. Future research should further explore whether a continuity of carer model focusing on antenatal and postnatal care delivery is a feasible and sustainable model of care for all women.

Crystal structures of the Dab homology domains of mouse disabled 1 and 2.

Disabled (Dab) 1 and 2 are mammalian homologues of Drosophila DAB. Dab1 is a key cytoplasmic mediator in Reelin signaling that controls cell positioning in the developing central nervous system, whereas Dab2 is an adapter protein that plays a role in endocytosis. DAB family proteins possess an amino-terminal DAB homology (DH) domain that is similar to the phosphotyrosine binding/phosphotyrosine interaction (PTB/PI) domain. We have solved the structures of the DH domains of Dab2 (Dab2-DH) and Dab1 (Dab1-DH) in three different ligand forms, ligand-free Dab2-DH, the binary complex of Dab2-DH with the Asn-Pro-X-Tyr (NPXY) peptide of amyloid precursor protein (APP), and the ternary complex of Dab1-DH with the APP peptide and inositol 1,4,5-trisphosphate (Ins-1,4,5-P3, the head group of phosphatidylinositol-4,5-diphosphate (PtdIns-4,5-P2)). The similarity of these structures suggests that the rigid Dab DH domain maintains two independent pockets for binding of the APP/lipoprotein receptors and phosphoinositides. Mutagenesis confirmed the structural determinants specific for the NPXY sequence and PtdIns-4,5-P2 binding. NMR spectroscopy confirmed that the DH domain binds to Ins-1,4,5-P3 independent of the NPXY peptides. These findings suggest that simultaneous interaction of the rigid DH domain with the NPXY sequence and PtdIns-4,5-P2 plays a role in the attachment of Dab proteins to the APP/lipoprotein receptors and phosphoinositide-rich membranes.

Aspects of the history of nutrition since 1876.

Since 1876, developments in nutritional science have followed those in chemistry, physiology, biochemistry and medicine. The essential relationship between food and body energy has been elucidated. The aetiology of diseases long known in human history has been traced to deficiencies of specific nutrients, the 'vitamins', required in very small amounts. These substances have been isolated, identified and synthesised. Research in infant malnutrition has led to the recognition that comparatively small changes in biochemical programming during growth and development may cause disease later in life. Dietary 'roughage' has been found to have significance in disease prevention and prospects for the very sick have been improved by the development of alternative feeds. Knowledge of the human genome promises exciting new advances for nutrition in relation to public health and clinical medicine.

Dietary advice in the management of diabetes mellitus--history and current practice.

Diet has been recognised for over three thousand years as being vital to the overall management of diabetes mellitus (DM). Today dietary advice for the person with diabetes continues to play just as an important role, not just as regards the day to day control but also in respect of the prevention of complications. The history of dietary advice for diabetes is examined as well as current dietary advice.

Ontogeny of a photic response in the suprachiasmatic nucleus in the Siberian hamster (Phodopus sungorus).

The ontogeny of photic responsiveness in the suprachiasmatic nucleus of the Siberian hamster (Phodopus sungorus) was studied using the enhanced expression of the immediate early gene c-fos as a marker of neuronal activation. c-fos expression was assessed by immunocytochemical localization of its protein product. Hamsters were kept on a 16 h light:8 h dark photocycle. The adult Siberian hamster showed a marked increase in the number of c-fos-immunoreactive (c-fos-ir) cells within the suprachiasmatic nuclei (SCN) in response to a 1 h light pulse delivered 1-3 h after lights off, in comparison to controls kept in the dark. This is consistent with previous studies in the Syrian hamster and rat. The development of the photic response was examined. The first study investigated the effects of a light pulse on c-fos induction in pups at 5, 9, 12 and 24 postnatal days of age (PD). The suprachiasmatic region was identified by immunocytochemical localization of peptide-histidine-isoleucine in adjacent sections, a peptide expressed early in the development of the rodent SCN. The distribution of c-fos-ir cells was also compared with the location of retinal efferents, as determined by intraocular injection of the tract tracer cholera toxin B subunit 24 h previously. At PD 9, 12 and 24, significant increases in the number of c-fos-ir cells occurred in the light pulsed animals in comparison to age-matched control animals which were moved within the non-illuminated room to provide a 'dark' pulse.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuclear light scattering, disulfide formation and membrane damage in lenses of older guinea pigs treated with hyperbaric oxygen.

Nuclear cataract, a major cause of loss of lens transparency in the aging human, has long been thought to be associated with oxidative damage, particularly at the site of the nuclear plasma membrane. However, few animal models have been available to study the mechanism of the opacity. Hyperbaric oxygen (HBO) has been shown to produce increased nuclear light scattering (NLS) and nuclear cataract in lenses of mice and human patients. In the present study, older guinea pigs (Initially 17-18 months of age) were treated with 2.5 atmospheres of 100% O2 for 2-2.5-hr periods, three times per week, for up to 100 times. Examination by slit-lamp biomicroscopy showed that exposure to HBO led to increased NLS in the lenses of the animals after as few as 19 treatments, compared to lenses of age-matched untreated and hyperbaric air-treated controls. The degree of NLS and enlargement of the lens nucleus continued to increase until 65 O2-treatments, and then remained constant until the end of the study. Exposure to O2 for 2.5 instead of 2 hr accelerated the increase in NLS; however, distinct nuclear cataract was not observed in the animals during the period of investigation. A number of morphological changes in the experimental lens nuclei, as analysed by transmission electron microscopy, were similar to those recently reported for human immature nuclear cataracts (Costello, Oliver and Cobo, 1992). O2-induced damage to membranes probably acted as scattering centers and caused the observed increased NLS. A general state of oxidative stress existed in the lens nucleus of the O2-treated animals, prior to the first appearance of increased NLS, as evidenced by increased levels of protein-thiol mixed disulfides and protein disulfide. The levels of mixed disulfides in the experimental nucleus were remarkably high, nearly equal to the normal level of nuclear GSH. The level of GSH in the normal guinea pig lens decreased with age in the nucleus but not in the cortex; at 30 months of age the nuclear level of GSH was only 4% of the cortical value. HBO-induced changes in the lens nucleus included loss of soluble protein, increase in urea-insoluble protein and slight decreases in levels of GSH and ascorbate; however, there was no accumulation of oxidized glutathione. Intermolecular protein disulfide in the experimental nucleus consisted mainly of gamma-crystallin, but crosslinked alpha-, beta- and zeta-crystallins were also present.(ABSTRACT TRUNCATED AT 400 WORDS)

Ascorbic acid, zinc and wound healing.

An examination of the biochemical roles of vitamin C and zinc in wound healing and of circumstances in which supplements may help the process.

Malignant disease: nutritional implications of disease and treatment.

Protein-energy malnutrition (PEM) is common in cancer patients and may develop into the syndrome known as 'cancer cachexia'. This is characterised by complex disturbances in carbohydrate, lipid, protein, and electrolyte metabolism. The aetiology is equally complex, with host and therapeutic factors contributing to the reduced food intake and effects on host tissues. Anorexia is of prime importance, differing in its cause from one patient to another and often presenting a barrier to successful nutritional support. Further research is necessary to elucidate the interaction of central and peripheral factors that may be involved in the aetiology of anorexia. Because of the interplay of biochemical, physiological, and psychological consequences of cancer, the nutritional support of the patient presents a considerable challenge to the caring professions.

Ascorbic acid supplementation and five year survival rates in women with early breast cancer.

The effect of long term ascorbic acid (AA) supplementation (3g per day) on 27 women with early breast cancer has been investigated. For comparison a similar but limited study was carried out in patients with benign breast disease. The responses of leucocyte levels of AA to supplementation provided some evidence to suggest that the metabolism and utilisation of the vitamin may be different in these patients. In addition longitudinal measurements of urinary hydroxyproline/creatinine (OHPro/Cr) ratio were carried out in these patients. The long term ingestion of AA did not appear to affect the prognosis of the disease in the early breast cancer group. Similar 5 year survival rates were seen in the unsupplemented and supplemented cancer groups.

Effect of large doses of ascorbic acid in man on some nitrogenous components of urine.

Base-line values for the excretion of urea N, amine N, creatinine, uric acid and cysteine were measured in three consecutive 24-h urine collections from 16 healthy volunteers. The subjects then took 1 g ascorbic acid three times a day after meals for 7 days. Twenty-four hour urine samples were collected on the 1st, 3rd, 5th and 7th days of the study. Where possible, a further 24-h sample was collected a minimum of 10 d after the end of the study. Administration of 3 g/d of ascorbic acid had no effect on urine volume, pH or the excretion of urea, amino N or creatinine. It caused a transient increase in uric acid excretion but an immediate and sustained increase in the excretion of cysteine. This study provides no evidence for an effect of high doses of ascorbic acid on urinary stone formation but does suggest competition for important co-factors in the metabolism of drugs.

Some effects of a food supplement in elderly hospital patients: a longitudinal study.

The effect of giving a food supplement for 12 weeks to 12 elderly, clinically stable, patients was investigated longitudinally. During the period of supplementation, the mean grip strength, whole blood and plasma ascorbic acid concentration, serum and red cell folic acid and plasma vitamin D concentrations increased, and decreased when the supplement was stopped. Thiamin status, as indicated by the red cell 'TPP value', also increased in response to the supplement and decreased when the supplement was stopped. It is concluded that a food supplement of the type given in this study could be useful in preventing nutrient deficiencies in old people.

Effect of pharmacological doses of ascorbic acid on the hepatic microsomal haemoproteins in the guinea-pig.

1. Ascorbic acid deficiency results in a reduction in the activity of the hepatic mixed function oxidase systems in the guinea-pig. In this study, male Dunkin-Hartley guinea-pigs were given 0, 50, 100, 200 or 300 mg ascorbic acid/d in two equal doses in buffered sucrose solution (200 g/l) for 4 d. Controls received an equal volume of sucrose solution. 2. A dose of 50 mg ascorbic acid/d resulted in a significant rise in the specific activities of both cytochromes P-450 and b5. At doses of 200 and 300 mg ascorbic acid/d the concentration of both haemoproteins was significantly lower than the control values. These effects were mirrored by total microsomal haem concentration. 3. These results suggest that when given in large doses, ascorbic acid ceases to act simply as a vitamin and should be considered a drug competing for substrates and cofactors with co-administered drugs and endogenous substrates such as cholesterol.

Effect of large doses of ascorbic acid on the mixed function oxidase system in guinea pig liver.

Reports of the beneficial effects of large doses of ascorbic acid have stressed its water solubility and non-toxic properties. In this study male guinea pigs, dosed with 150 mg twice daily, ascorbic acid, demonstrated no differences in effect on liver weight, body weight or hepatic total protein when compared with controls. The activities of NADPH-dependent cytochrome c reductase, N-demethylase (Type I) and O-de-ethylase enzymes (Type II) remained unaffected, but the activity of the Type I hydroxylating enzyme, biphenyl-4-hydroxylase, and the amounts of cytochromes P-450 and b5 were significantly reduced. Total microsomal haem proteins were reduced and mirrored the effects in cytochromes P-450 and b5. The rate-limiting enzyme in haem synthesis, delta-amino-laevulinic acid synthetase, rose in the ascorbic acid group and this was associated with a fall in activity of the haem degrading enzyme, microsomal haem oxygenase. Thus, large amounts of ascorbic acid have similar effects to those found in scorbutic animals and appear to interfere with the construction of the cytochrome P-450 molecule.

Effect of corticosterone on the plasma and tissue concentrations of vitamin A in rats.

The administration of large doses of corticosterone to normal adult male rats resulted in a rapid loss of vitamin A from the plasma, liver, adrenals and thymus. Of the organs studied, the thymus appeared to be the most sensitive to treatment. The steroid-mediated depression of plasma and tissue contents of vitamin A was reversed when animals were treated with corticosterone in combination with vitamin A.

Effects of 5-fluorouracil on the thiamin status of adult female rats.

The effect of 5-fluorouracil on the thiamin status of normal female adult rats has been investigated. Pre-treatment of the animals with the cytotoxic drug daily for 3 successive days resulted in a significant decrease in hepatic concentrations of thiamin concomitant with a decrease in thiamin-dependent transketolase enzyme activity and an increase in thiamin-pyrophosphate-(TPP-)stimulating effect in whole blood when compared with those of pair-fed control animals. The TPP effect of transketolase enzyme activity was also increased by 5-fluorouracil in vitro. Furthermore, the treatment with 5-fluorouracil resulted in decreased liver and spleen concentrations without affecting the urinary excretory levels of thiamin in animals supplemented with large doses of the vitamin. Giving a dose comparable to a human therapeutic dose caused a similar increase in the TPP effect. These results indicate that treatment with 5-fluorouracil may be associated with thiamin deficiency by increasing either the utilization or the breakdown of thiamin.

Haematological studies on vegans.

1. The concentrations of vitamin B12 and folate in the serum and folate in the erythrocytes were determined and full blood counts made on a series of caucasian vegans and omnivore controls. 2. The blood counts and films were normal in all the vegans and no subject had a haemoblobin concentration below the lower limit of normality. 3. Although within the normal range, male but not female vegans had lower values for erythrocyte counts and higher values for mean corpuscular volume and mean corpuscular haemoglobin than their controls regardless of whether they were taking vitamin B12 supplements or not. 4. The mean serum vitamin B12 concentration was lower in the vegans not taking vitamin B12 supplements and in those using foods supplemented with the vitamin than in the controls, but in no subject was it below 80 ng/1. 5. The serum folate concentrations were higher in the vegans than in their controls. The mean value for erythrocyte folate tended to be greater in the vegans not taking vitamin B12 supplements. No subject had an erythrocyte folate concentration of less than 100 microgram/1. 6. It is concluded that megaloblastic anaemia is very rare in caucasian vegans and that a diet consisting entirely of plant foods is generally adequate to promote normal blood formation providing it is composed of a mixture of unrefined cereals, pulses, nuts, fruit and vegetables and is supplemented with vitamin B12.