Parturition and the perinatal period: can mode of delivery impact on the future health of the neonate?

Caesarean section and instrumental delivery rates are increasing in many parts of the world for a range of cultural and medical reasons, with limited consideration as to how 'mode of delivery' may impact on childhood and long-term health. However, babies born particularly by pre-labour caesarean section appear to have a subtly different physiology from those born by normal vaginal delivery, with both acute and chronic complications such as respiratory and cardio-metabolic morbidities being apparent. It has been hypothesized that inherent mechanisms within the process of labour and vaginal delivery, far from being a passive mechanical process by which the fetus and placenta are expelled from the birth canal, may trigger certain protective developmental processes permissive for normal immunological and physiological development of the fetus postnatally. Traditionally the primary candidate mechanism has been the hormonal surges or stress response associated with labour and vaginal delivery, but there is increasing awareness that transfer of the maternal microbiome to the infant during parturition. Transgenerational transmission of disease traits through epigenetics are also likely to be important. Interventions such as probiotics, neonatal gut seeding and different approaches to clinical care have potential to influence parturition physiology and improve outcomes for infants.

Maternal obesity programs offspring non-alcoholic fatty liver disease through disruption of 24-h rhythms in mice.

BACKGROUND: Maternal obesity increases offspring propensity to metabolic dysfunctions and to non-alcoholic fatty liver disease (NAFLD), which may lead to cirrhosis or liver cancer. The circadian clock is a transcriptional/epigenetic molecular machinery synchronising physiological processes to coordinate energy utilisation within a 24-h light/dark period. Alterations in rhythmicity have profound effects on metabolic pathways, which we sought to investigate in offspring with programmed NAFLD. METHODS: Mice were fed a standard or an obesogenic diet (OD), before and throughout pregnancy, and during lactation. Offspring were weaned onto standard or an OD at 3 weeks postpartum and housed in 12:12 light/dark conditions. Biochemical and histological indicators of NAFLD and fibrosis, analysis of canonical clock genes with methylation status and locomotor activity were investigated at 6 months. RESULTS: We show that maternal obesity interacts with an obesogenic post-weaning diet to promote the development of NAFLD with disruption of canonical metabolic rhythmicity gene expression in the liver. We demonstrate hypermethylation of BMAL-1 (brain and muscle Arnt like-1) and Per2 promoter regions and altered 24-h rhythmicity of hepatic pro-inflammatory and fibrogenic mediators. CONCLUSIONS: These data implicate disordered circadian rhythms in NAFLD and suggest that disruption of this system during critical developmental periods may be responsible for the onset of chronic liver disease in adulthood.

A molecular phylogeny of bryozoans.

We present the most comprehensive molecular phylogeny of bryozoans to date. Our concatenated alignment of two nuclear ribosomal and five mitochondrial genes includes 95 taxa and 13,292 nucleotide sites, of which 8297 were included. The number of new sequences generated during this project are for each gene:ssrDNA (32), lsrDNA (22), rrnL (38), rrnS (35), cox1 (37), cox3 (34), and cytb (44). Our multi-gene analysis provides a largely stable topology across the phylum. The major groups were unambiguously resolved as (Phylactolaemata (Cyclostomata (Ctenostomata, Cheilostomata))), with Ctenostomata paraphyletic. Within Phylactolaemata, (Stephanellidae, Lophopodidae) form the earliest divergent clade. Fredericellidae is not resolved as a monophyletic family and forms a clade together with Plumatellidae, Cristatellidae and Pectinatellidae, with the latter two as sister taxa. Hyalinella and Gelatinella nest within the genus Plumatella. Cyclostome taxa fall into three major clades: i. (Favosipora (Plagioecia, Rectangulata)); ii. (Entalophoroecia ((Diplosolen, Cardioecia) (Frondipora, Cancellata))); and iii. (Articulata ((Annectocyma, Heteroporidae) (Tubulipora (Tennysonia, Idmidronea)))), with suborders Tubuliporina and Cerioporina, and family Plagioeciidae each being polyphyletic. Ctenostomata is composed of three paraphyletic clades to the inclusion of Cheilostomata: ((Alcyonidium, Flustrellidra) (Paludicella (Anguinella, Triticella)) (Hislopia (Bowerbankia, Amathia)) Cheilostomata); Flustrellidra nests within the genus Alcyonidium, and Amathia nests within the genus Bowerbankia. Suborders Carnosa and Stolonifera are not monophyletic. Within the cheilostomes, Malacostega is paraphyletic to the inclusion of all other cheilostomes. Conopeum is the most early divergent cheilostome, forming the sister group to ((Malacostega, Scrupariina, Inovicellina) ((Hippothoomorpha, Flustrina) (Lepraliomorpha, Umbonulomorpha))); Flustrina is paraphyletic to the inclusion of the hippothoomorphs; neither Lepraliomorpha nor Umbonulomorpha is monophyletic. Ascophorans are polyphyletic, with hippothoomorphs grouping separately from lepraliomorphs and umbonulomorphs; no cribrimorphs were included in the analysis. Results are discussed in the light of molecular and morphological evidence. Ancestral state reconstruction of larval strategy in Gymnolaemata revealed planktotrophy and lecithotrophy as equally parsimonious solutions for the ancestral condition. More comprehensive taxon sampling is expected to clarify this result. We discuss the extent of non-bryozoan contaminant sequences deposited in GenBank and their impact on the reconstruction of metazoan phylogenies and those of bryozoan interrelationships.

Islets in early life are resistant to detrimental effects of a high-fat maternal diet: a study in rats.

Offspring of rats fed high-fat diets during pregnancy and lactation develop glucose intolerance and islet dysfunction in adulthood. Because other models of developmental programming of glucose intolerance are associated with defective islet development, we investigated whether high-fat exposure during fetal or neonatal life impairs islet development and function, thereby contributing to islet dysfunction in later life. Female rats were fed control or high-fat diets and their pups cross-fostered after birth to represent 4 groups with each combination of control and high-fat diet for the natural and foster mother. In a time course study, pups were kept with the natural mother until weaning. Pancreases were analysed for insulin content, beta cell mass, and islet number. Isolated islets were studied for insulin secretory responses and susceptibility to palmitate-induced apoptosis assessed by caspases 3/9 activity. Pancreatic insulin content and beta cell mass were increased in pups exposed to maternal high-fat diets after birth, whereas glucose-stimulated insulin secretion from islets of high-fat offspring at 5 and 11 days of age was lower than controls. Islets from control rats of 2-14 days of age were resistant to the pro-apoptotic effects of palmitate seen in older animals. The immature beta cell is therefore insensitive to toxic effects of palmitate and may compensate for the inhibitory effects on insulin secretion by increasing beta cell mass. The data suggest that susceptibility to glucose intolerance in offspring of dams fed high-fat diets may not be a consequence of deleterious effects on beta cell mass in early life.

Decoupled temporal patterns of evolution and ecology in two post-Paleozoic clades.

Counts of taxonomic diversity are the prevailing standards for documenting large-scale patterns of evolution in the fossil record. However, the secular pattern of relative ecological importance between the bryozoan clades Cyclostomata and Cheilostomata is not reflected fully in compilations of generic diversity or within-fauna species richness, and the delayed ecological recovery of the Cheilostomata after the mass extinction at the Cretaceous-Tertiary boundary is missed entirely. These observations demonstrate that evolutionary success and ecological dominance can be decoupled and profoundly different, even over tens of millions of years.

Synthesis of human plasminogen by the liver.

Genetic types of plasminogen were determined from a donor and a recipient before and after hepatic homotransplantation. Examination of the plasminogen types demonstrated that the liver is the principal site of synthesis of human plasminogen.

Cheilostome Bryozoa of the northern Persian Gulf, Iran.

This paper describes 15 cheilostome bryozoan species obtained from 15 sampling sites along the northern coast of the Persian Gulf in Iran. Two of the cheilostomes are described as new species: Parasmittina cryptoavicularia n. sp. and Trematooecia persica n. sp. The majority of species found in this study (67%) have a tropical to subtropical Indo-Pacific distribution, while the remainder are more widely distributed. Several are fouling species known from warmer seas around the globe. Further sampling efforts are needed to obtain a better estimate of the true bryozoan diversity in the region which is almost certainly much greater than the 15 species described in this study.

Overlapping generations can promote altruistic behavior.

We use an inclusive fitness model to study the evolution of altruism in a patch-structured population in which there is positive probability of breeder survival from one generation to the next. We find first that breeder survival promotes altruism and second that there is a marked difference between benefits of fecundity and benefits of survival. Under the first altruism is more strongly favored, and under the second altruism is less strongly favored than in a randomly mixing population.

Novel 3-hydroxy-2(1H)-pyridinones. Synthesis, iron(III)-chelating properties, and biological activity.

The synthesis of a range of novel bidentate and hexadentate ligands containing the chelating moiety 3-hydroxy-2(1H)-pyridinone is described. The pKa values of the ligands and the stability constants of their iron(III) complexes have been determined. The stability constant of the iron(III) complex of one of the hexadentate ligands is comparable to that of desferrioxamine B. The distribution coefficients of the ligands and their iron(III) complexes were also determined. One of the novel hexadentate compounds has been shown to markedly enhance iron(III) excretion from both hepatocytes and iron-overloaded mice.

Synthesis, physicochemical properties, and biological evaluation of N-substituted 2-alkyl-3-hydroxy-4(1H)-pyridinones: orally active iron chelators with clinical potential.

The synthesis of a range of novel bidentate ligands containing the chelating moiety 3-hydroxy-4(1H)-pyridinone is described. The pKa values of the ligands and the stability constants of their iron(III) complexes have been determined. The crystal structures of one of the ligands and one of the iron(III) complexes are presented. The distribution coefficients of the ligands are reported and are related to the ability of the ligands to remove iron from hepatocytes. The influence of 3-hydroxy-4(1H)-pyridinones on oxidative damage to cells is described. In contrast to the iron chelator in current therapeutic use, desferrioxamine-B, many of the bidentate ligands described in this study are orally active in iron-overloaded mice.

The effect of hyperglycaemia on function of rat isolated mesenteric resistance artery.

1. Noradrenaline sensitivity and acetylcholine-induced relaxation were investigated in mesenteric resistance arteries from female Wistar rats (220-250 g) following exposure to isotonic supraphysiological glucose solutions (20 and 45 mM, in physiological buffer, 2 h incubation). 2. Arteries incubated in 20 mM glucose demonstrated enhanced noradrenaline sensitivity compared with those in physiological buffer. 3. Profoundly impaired endothelium-dependent relaxation to acetylcholine was observed in arteries incubated in 20 and 45 mM glucose. 4. Indomethacin (10 microM) normalized noradrenaline sensitivity in 20 mM glucose, but unmasked an enhanced maximum response in 20 and 45 mM glucose relative to controls. 5. Addition of L-arginine (0.1 mM) prevented the abnormality of acetylcholine-induced relaxation in the 20 mM glucose medium and significantly improved relaxation in 45 mM glucose. 6. The aldose reductase inhibitor, ponalrestat (10(-5) M, ZENECA Pharmaceuticals), prevented impaired acetylcholine-mediated relaxation in 20 mM glucose and significantly improved relaxation in 45 mM glucose. 7. Indomethacin (10 microM) improved maximum relaxation but did not alter impaired sensitivity to acetylcholine in the high glucose media (20 and 45 mM). 8. Superoxide dismutase (SOD, 150 u ml-1) also prevented impaired acetylcholine-induced relaxation in 20 mM glucose but not in 45 mM glucose. 9. Endothelium-independent relaxation to sodium nitroprusside (SNP, 10(-9)-10(-5) mM) was normal in 20 mM glucose but was slightly, although significantly impaired by 45 mM glucose. 10. Enhanced responsiveness of rat isolated mesenteric resistance arteries to noradrenaline caused by elevated glucose would appear to be mediated through abnormal cyclo-oxygenase activity and the reduced tonic release of nitric oxide. 11. Hyperglycaemia may lead to abnormal endothelium-dependent relaxation in these arteries through several mechanisms which include a role for increased free radical production, polyol pathway activation and altered L-arginine metabolism.

Endothelium-dependent relaxation and noradrenaline sensitivity in mesenteric resistance arteries of streptozotocin-induced diabetic rats.

1. Noradrenaline sensitivity and acetylcholine-induced relaxation were investigated in mesenteric resistance arteries of control and streptozotocin-induced diabetic rats. 2. The diabetic rats demonstrated enhanced vascular sensitivity to noradrenaline compared with age-matched controls (pEC50 5.99 +/- 0.06 for diabetic rats, n = 25, versus 5.82 +/- 0.03 for controls, n = 45, P < 0.05). 3. Significant impairment of acetylcholine-induced relaxation was observed in arteries from the diabetic animals compared with controls (pEC50 6.81 +/- 0.17 for diabetic rats, n = 21, versus 7.54 +/- 0.17 for controls, n = 45, P < 0.001). 4. The difference between acetylcholine-induced relaxation in diabetic and control arteries remained in the presence of 10 microM indomethacin (pEC50 6.41 +/- 0.11 for diabetic rats, n = 16, versus 7.59 +/- 0.08 for controls, n = 20, P < 0.001). 5. The nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA, 1 mM) produced profound inhibition of acetylcholine-induced relaxation in diabetic arteries but partial inhibition in controls. The incomplete inhibition of acetylcholine-induced relaxation by L-NMMA in the control arteries was the result of ineffective inhibition of nitric oxide synthase since an alternative inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 0.1 mM), led to similar inhibition to that seen in the diabetic arteries with L-NMMA. The endothelium-derived relaxing factor (EDRF)-mediated component of acetylcholine-induced relaxation determined by use of the nitric oxide synthase inhibitors was, therefore, apparently reduced in diabetic rats compared with control animals.6. In further experiments L-NAME was found to enhance the response to noradrenaline in control rats but not in diabetic animals, suggesting that the abnormal response to noradrenaline in the diabetic animals was also due to reduced EDRF release.7. Nitroprusside-induced relaxation (endothelium-independent) was similar in arteries from control anddiabetic rats (pEC5o 7.61 +/- 0.13 for diabetic arteries, n = 18, versus 7.68 +/- 0.15 in the controls, n = 20, P not significant).8. These results suggest that endothelial function is abnormal in mesenteric resistance arteries of streptozotocin-induced diabetic rats and that this is predominantly due to reduced EDRF release.

Prevention by insulin treatment of endothelial dysfunction but not enhanced noradrenaline-induced contractility in mesenteric resistance arteries from streptozotocin-induced diabetic rats.

1. Streptozotocin-induced diabetic rats (Wistar) were implanted with sustained release insulin pellets (release rate = 4 u day-1) or with placebo pellets (palmitic acid) from the onset of glycosuria. 2. Noradrenaline sensitivity, endothelium-dependent relaxation to acetylcholine and endothelium-independent relaxation to sodium nitroprusside were assessed in mesenteric resistance arteries from the insulin-treated (IT) diabetic animals and compared to placebo-implanted (PI) diabetics and age-matched controls. 3. Arteries from PI-diabetic rats (8-10 weeks) demonstrated an enhanced maximal response to noradrenaline compared to controls, which was not prevented by insulin treatment (control 2.65 +/- 0.17 mN mm-1, n = 18 arteries versus PI-diabetic 3.73 +/- 0.40 mM mm-1, n = 5, P < 0.05; control versus IT-diabetic 4.02 +/- 0.19 mN mm-1, n = 22, P < 0.001). Sensitivity to noradrenaline was similar between the three groups. 4. In the presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), IT and PI arteries were more sensitive to noradrenaline than control arteries (pEC50: control 5.75 +/- 0.08, n = 17, versus PI-diabetic 6.14 +/- 0.09, n = 8, P < 0.05; control versus IT-diabetic 6.38 +/- 0.08, n = 20, P < 0.001). 5. The maximum contractile response to depolarizing 125 mM K+ was significantly enhanced in IT-diabetic arteries but not PI-diabetic when compared to control arteries (maximum response: control 3.74 +/- 0.15 mN mm-1, n = 18, versus PI-diabetic 3.61 +/- 0.19 mN mm-1, n = 11, NS; control versus IT-diabetic 4.66 +/- 0.18 mN mm-1, n = 22, P < 0.001). 6. Endothelium-dependent relaxation to acetylcholine was profoundly impaired in the PI-diabetic arteries, but in the IT-diabetic arteries was not significantly different from controls (pEC50: control 7.64 +/- 0.19, n = 17, versus PI-diabetic 6.07 +/- 0.12, n = 8, P < 0.001; control versus IT-diabetic 7.36 +/- 0.09, n = 22, NS). 7. Endothelium-independent relaxation to sodium nitroprusside was slightly but significantly impaired in the PI-diabetic arteries, but was not significantly different in the IT-diabetic arteries compared to controls (pEC50: control 7.78 +/- 0.10, n = 13, versus PI-diabetic 7.31 +/- 0.13, n = 13, P <0.05; control,versus IT-diabetic 7.64 +/- 0.09, n = 16, NS).

Endothelial function in the isolated perfused mesentery and aortae of rats with streptozotocin-induced diabetes: effect of treatment with the aldose reductase inhibitor, ponalrestat.

1. Noradrenaline sensitivity and relaxation to acetylcholine were investigated in the isolated perfused mesentery and in aortic rings of control and streptozotocin (STZ)-induced (50 mg kg-1) diabetic Charles River rats. 2. In addition, noradrenaline sensitivity and acetylcholine relaxation were similarly assessed in streptozotocin-induced diabetic rats treated from the time of onset of diabetes with the aldose reductase inhibitor, ponalrestat (100 mg kg-1 day-1). 3. The untreated diabetic rats (2-10 weeks after injection of STZ) demonstrated enhanced vascular sensitivity to noradrenaline in the perfused mesenteric arterial tree, compared with age matched controls (pEC50 [-log concentration (M)]: diabetic 5.62 +/- 0.09, n = 18, versus control 5.23 +/- 0.07, n = 16, P < 0.01). 4. Acetylcholine-induced relaxation was significantly impaired in the perfused mesentery of the diabetic animals compared to controls (pED50 [-log dose (mol)]: diabetic 9.87 +/- 0.10, n = 20, versus controls, 10.29 +/- 0.09, n = 20, P < 0.05). 5. In contrast, the aortic ring preparations demonstrated no significant functional differences between the diabetic and control groups in response to either noradrenaline (pEC50: diabetic 7.66 +/- 0.08, n = 15, versus controls 7.55 +/- 0.06, n = 15, NS), or acetylcholine (pEC50: diabetics 7.30 +/- 0.06, n = 15, versus controls 7.40 +/- 0.09, n = 15, NS). 6. Treatment with the aldose reductase inhibitor, ponalrestat, did not affect the increased vascular reactivity to noradrenaline, or impaired relaxation to acetylcholine in the perfused mesentery.

Effects of GnRH antagonist treatment on follicular development and angiogenesis in the primate ovary.

Angiogenesis is required for normal follicular development but the role of gonadotrophins in the control of follicular angiogenesis remains to be elucidated. This study investigated the effects of treatment with GnRH antagonist in vivo on follicular development and angiogenesis in the marmoset. GnRH antagonist was administered on either follicular day 0 or day 5 of the 10-day follicular phase with ovaries collected on day 10. Ovaries from control marmosets were studied at day 5 (mid follicular phase) and day 10 (periovulatory period). Ovaries were fixed, serial sectioned and subjected to morphological analysis and immunocytochemistry to determine cell proliferation and follicular endothelial cell area and in situ hybridization to assess changes in expression of vascular endothelial growth factor (VEGF). Treatment with GnRH antagonist from day 0-10 resulted in an absence of dominant preovulatory follicles seen in controls. In the remaining tertiary follicles granulosa, theca and endothelial cell proliferation was reduced, resulting in a minor reduction in vascular density. However, VEGF mRNA expression was unaffected by treatment. Treatment from day 5-10 did not prevent development of ovulatory size follicles, but they were atretic and lacked VEGF mRNA. These results suggest that while VEGF expression in the preovulatory follicle is under gonadotrophic control it is not dependent on normal gonadotrophin secretion in tertiary follicles, indicating that there are other paracrine factors regulating VEGF expression in the developing ovarian follicle.

Facilitated uptake of zinc into human erythrocytes. Relevance to the treatment of sickle-cell anaemia.

The ability of a number of heterocyclic metal chelators to deliver zinc into red cells, to release the liganded zinc to haemoglobin and thereby cause a left shift in the oxygen dissociation curve of intact red cells has been investigated. Incubation of neutrally charged zinc-pyrone and zinc-pyridin-2-one complexes with red cells led to the rapid accumulation of zinc within cells, whereas unliganded zinc in the form of zinc acetate, zinc chloride or zinc sulphate accumulated only slowly. The rate at which zinc was delivered to red cells by pyrone and pyridin-2-one ligands increased with increasing lipid solubility of the ligands. The uptake of zinc into both normal adult and sickle red cells was associated with a dose-dependent increase in the oxygen affinity of haemoglobin. The degree of left shift in the oxygen dissociation curve following the incubation of red cells with zinc-pyrone and -pyridin-2-one complexes suggests that these complexes may find application as agents to increase the oxygen affinity of haemoglobin in sickle cell disease and thereby decrease the probability of intravascular sickling at low tissue oxygen tensions. Ethylmaltol appears to be a particularly useful agent due to its known low toxicity.

Urinary excretion of essential metals following intravenous calcium disodium edetate: an estimate of free zinc and zinc status in man.

Ethylenediaminetetraacetic acid (EDTA) is a powerful metal chelating agent used in the treatment of lead poisoning. EDTA also binds strongly to other metals. Thus, following intravenous infusion of CaNa2EDTA in healthy subjects the urinary excretion of calcium, copper, iron, magnesium and zinc were assessed. CaNa2EDTA significantly increased the urinary excretion of all metals except magnesium with greatest increases for iron (x 3.8 above baseline) and zinc (x 22). In addition, an in vitro dialysis study with a simplified serum showed that zinc (4.1 X 10(-3) mumol/h) was taken up more rapidly than iron (2.9 X 10(-3) mumol/h) by EDTA. The degree of binding of iron and zinc by EDTA depends on two factors: namely, the affinity of EDTA for Zn2+ and Fe3+, and the levels of unbound hydrated Zn2+ and Fe3+ ('free' ions). Despite differences in the rate of chelation of Zn2+ and Fe3+ by EDTA we show that the measurements of (a) circulating free iron, from routine clinical measurements of transferrin bound iron, and (b) the ratio of zinc:iron excreted in urine could provide an estimate of circulating free zinc, and thereby of zinc status, in man. In addition, EDTA treatment should be evaluated for patients with iron overload.

Release of iron from ferritin molecules and their iron-cores by 3-hydroxypyridinone chelators in vitro.

Ferritin molecules contain 24 subunits forming a shell around an inorganic iron-core. Release of iron(III) from ferritin and its isolated iron-cores by a series of hydroxypyridinone chelators with high affinities for iron(III) has been compared. The results collectively suggest that the chelators act by penetrating the protein shell and interacting directly with the iron-core in ferritin. Iron(III) is probably removed bound to a single ligand, but once outside the protein shell, the trihydroxypyridinone iron(III) complex predominates. The order of effectiveness of a group of pyridinones found for iron removal from ferritin molecules in solution differs from that obtained with hepatocytes in culture or with whole animals, where membrane solubility and other factors may modulate the response.