Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 222
Filter
Add more filters

Publication year range
1.
Nature ; 625(7996): 760-767, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38092039

ABSTRACT

GDF15, a hormone acting on the brainstem, has been implicated in the nausea and vomiting of pregnancy, including its most severe form, hyperemesis gravidarum (HG), but a full mechanistic understanding is lacking1-4. Here we report that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to the risk of HG. We confirmed that higher GDF15 levels in maternal blood are associated with vomiting in pregnancy and HG. Using mass spectrometry to detect a naturally labelled GDF15 variant, we demonstrate that the vast majority of GDF15 in the maternal plasma is derived from the feto-placental unit. By studying carriers of rare and common genetic variants, we found that low levels of GDF15 in the non-pregnant state increase the risk of developing HG. Conversely, women with ß-thalassaemia, a condition in which GDF15 levels are chronically high5, report very low levels of nausea and vomiting of pregnancy. In mice, the acute food intake response to a bolus of GDF15 is influenced bi-directionally by prior levels of circulating GDF15 in a manner suggesting that this system is susceptible to desensitization. Our findings support a putative causal role for fetally derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by prepregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.


Subject(s)
Growth Differentiation Factor 15 , Hyperemesis Gravidarum , Nausea , Vomiting , Animals , Female , Humans , Mice , Pregnancy , beta-Thalassemia/blood , beta-Thalassemia/metabolism , Fetus/metabolism , Growth Differentiation Factor 15/blood , Growth Differentiation Factor 15/metabolism , Hormones/blood , Hormones/metabolism , Hyperemesis Gravidarum/complications , Hyperemesis Gravidarum/metabolism , Hyperemesis Gravidarum/prevention & control , Hyperemesis Gravidarum/therapy , Nausea/blood , Nausea/complications , Nausea/metabolism , Placenta/metabolism , Vomiting/blood , Vomiting/complications , Vomiting/metabolism
2.
Mol Pharm ; 16(5): 1827-1838, 2019 05 06.
Article in English | MEDLINE | ID: mdl-30702301

ABSTRACT

Hyperlipidaemia is considered as one of the main risk factors associated with cardiovascular diseases (CVDs). Among different lipid-lowering agents used to manage hyperlipidaemia, statins are highly prescribed for management of hyperlipidaemia with simvastatin being one of the most common. Simvastatin is susceptible to extensive metabolism by CYP450 3A4 and 3A5, which are expressed both in the liver and the gastrointestinal tract. Nevertheless, the localization of these enzymes is site-dependent with lower concentration at the distal/proximal regions of the small intestine/colon. In addition to statins, medications such as antihypertensive agents and anticoagulants are introduced as adjuvants, for the treatment of cardiovascular disease. The aim of this study was to design a bilayer delivery system capable of delivering biphasic release of simvastatin and aspirin, within a fixed dose combination. A delayed release platform based on a combination of anionic polymers prepared using hot-melt extrusion was developed to delay the release of simvastatin. An optimized formulation tested for dissolution performance clearly demonstrated an ability to delay the release of simvastatin. In addition, an immediate release layer based on Kollidon VA64 was successfully developed to deliver aspirin. Both formulations were then manufactured as a bilayer drug delivery system (tablets and coextrudates), and the release performance was examined. On the basis of the obtained results, these formulations may be used as a platform for delivering a wide range of medications in a biphasic manner.


Subject(s)
Cardiovascular Diseases/complications , Cardiovascular Diseases/drug therapy , Drug Compounding/methods , Drug Delivery Systems/methods , Drug Design , Hyperlipidemias/complications , Hyperlipidemias/drug therapy , Aspirin/administration & dosage , Aspirin/chemistry , Dosage Forms , Drug Combinations , Drug Liberation , Hot Melt Extrusion Technology/methods , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Hydroxymethylglutaryl-CoA Reductase Inhibitors/chemistry , Polyethylene Glycols/chemistry , Polyvinyls/chemistry , Pyrrolidines/chemistry , Simvastatin/administration & dosage , Simvastatin/chemistry , Solubility , Vinyl Compounds/chemistry
3.
Mol Hum Reprod ; 21(3): 296-308, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25391298

ABSTRACT

Early human placental and embryonic development occurs in a physiologically low oxygen environment supported by histiotrophic secretions from endometrial glands. In this study, we compare the placental metabolomic profile in the first, second and third trimesters to determine whether the energy demands are adequately met in the first trimester. We investigated whether hypoxia-inducible factors, HIF-1α and/or HIF-2α, might regulate transcription during the first trimester. First and second trimester tissue was collected using a chorionic villus sampling-like (CVS) technique. Part of each villus sample was frozen immediately and the remainder cultured under 2 or 21% O2 ± 1 mM H2O2, and ±the p38 MAPK pathway inhibitor, PD169316. Levels of HIF-1α were assessed by western blotting and VEGFA, PlGF and GLUT3 transcripts were quantified by RT-PCR. Term samples were collected from normal elective Caesarean deliveries. There were no significant differences in concentrations of ADP, NAD(+), lactate, and glucose, and in the ATP/ADP ratio, across gestational age. Neither HIF-1α nor HIF-2α could be detected in time-zero CVS samples. However, culture under any condition (2 or 21% O2 ± 1 mM H2O2) increased HIF-1α and HIF-2α. HIF-1α and HIF-2α were additionally detected in specimens retrieved after curettage. HIF-1α stabilization was accompanied by significant increases in VEGFA and GLUT3 and a decrease in PlGF mRNAs. These effects were suppressed by PD169316. In conclusion, our data suggest that first trimester placental tissues are not energetically compromised, and that HIF-1α is unlikely to play an appreciable role in regulating transcriptional activity under steady-state conditions in vivo. However, the pathway may be activated by stress conditions.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Chorionic Villi/drug effects , Energy Metabolism/drug effects , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Oxygen/pharmacology , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Adult , Basic Helix-Loop-Helix Transcription Factors/genetics , Cell Hypoxia , Chorionic Villi/growth & development , Chorionic Villi/metabolism , Energy Metabolism/genetics , Female , Gene Expression Regulation, Developmental , Glucose Transporter Type 3/genetics , Glucose Transporter Type 3/metabolism , Humans , Hydrogen Peroxide/pharmacology , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Imidazoles/pharmacology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Placentation/physiology , Pregnancy , Pregnancy Trimesters , Primary Cell Culture , Signal Transduction , Transcription, Genetic , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
4.
Mol Pharm ; 11(10): 3471-83, 2014 Oct 06.
Article in English | MEDLINE | ID: mdl-25105340

ABSTRACT

The objective of this work was to investigate the feasibility of using a novel granulation technique, namely, fluidized hot melt granulation (FHMG), to prepare gastroretentive extended-release floating granules. In this study we have utilized FHMG, a solvent free process in which granulation is achieved with the aid of low melting point materials, using Compritol 888 ATO and Gelucire 50/13 as meltable binders, in place of conventional liquid binders. The physicochemical properties, morphology, floating properties, and drug release of the manufactured granules were investigated. Granules prepared by this method were spherical in shape and showed good flowability. The floating granules exhibited sustained release exceeding 10 h. Granule buoyancy (floating time and strength) and drug release properties were significantly influenced by formulation variables such as excipient type and concentration, and the physical characteristics (particle size, hydrophilicity) of the excipients. Drug release rate was increased by increasing the concentration of hydroxypropyl cellulose (HPC) and Gelucire 50/13, or by decreasing the particle size of HPC. Floating strength was improved through the incorporation of sodium bicarbonate and citric acid. Furthermore, floating strength was influenced by the concentration of HPC within the formulation. Granules prepared in this way show good physical characteristics, floating ability, and drug release properties when placed in simulated gastric fluid. Moreover, the drug release and floating properties can be controlled by modification of the ratio or physical characteristics of the excipients used in the formulation.


Subject(s)
Excipients/chemistry , Calorimetry, Differential Scanning , Cellulose/analogs & derivatives , Cellulose/chemistry , Chemistry, Pharmaceutical , Drug Compounding , Fats/chemistry , Fatty Acids/chemistry , Metronidazole/chemistry , Models, Theoretical , Oils/chemistry , Sodium Bicarbonate/chemistry , Thermogravimetry
5.
mBio ; 14(1): e0311622, 2023 02 28.
Article in English | MEDLINE | ID: mdl-36598261

ABSTRACT

Chronic gastric infection with Helicobacter pylori can lead to progressive tissue changes that culminate in cancer, but how H. pylori adapts to the changing tissue environment during disease development is not fully understood. In a transgenic mouse gastric metaplasia model, we found that strains from unrelated individuals differed in their ability to infect the stomach, to colonize metaplastic glands, and to alter the expression of the metaplasia-associated protein TFF3. H. pylori isolates from different stages of disease from a single individual had differential ability to colonize healthy and metaplastic gastric glands. Exposure to the metaplastic environment selected for high gastric colonization by one of these strains. Complete genome sequencing revealed a unique alteration in the frequency of a variant allele of the putative adhesin sabB, arising from a recombination event with the related sialic acid binding adhesin (SabA) gene. Mutation of sabB in multiple H. pylori strain backgrounds strongly reduced adherence to both normal and metaplastic gastric tissue, and highly attenuated stomach colonization in mice. Thus, the changing gastric environment during disease development promotes bacterial adhesin gene variation associated with enhanced gastric colonization. IMPORTANCE Chronic infection with Helicobacter pylori is the primary risk factor for developing stomach cancer. As disease progresses H. pylori must adapt to a changing host tissue environment that includes induction of new cell fates in the cells that line the stomach. We tested representative H. pylori isolates collected from the same patient during early and later stages of disease in a mouse model where we can rapidly induce disease-associated tissue changes. Only the later-stage H. pylori strains could robustly colonize the diseased stomach environment. We also found that the ability to colonize the diseased stomach was associated with genetic variation in a putative cell surface adhesin gene called sabB. Additional experiments revealed that SabB promotes binding to stomach tissue and is critical for stomach colonization by the late-stage strains. Thus, H. pylori diversifies its genome during disease progression and these genomic changes highlight critical factors for bacterial persistence.


Subject(s)
Helicobacter Infections , Helicobacter pylori , Stomach Neoplasms , Mice , Animals , Helicobacter pylori/genetics , Helicobacter pylori/metabolism , Persistent Infection , Adhesins, Bacterial/genetics , Adhesins, Bacterial/metabolism , Helicobacter Infections/microbiology , Gastric Mucosa/microbiology , Mice, Transgenic , Stomach Neoplasms/microbiology , Metaplasia/complications , Metaplasia/metabolism
6.
bioRxiv ; 2023 Jun 04.
Article in English | MEDLINE | ID: mdl-37398065

ABSTRACT

Human pregnancy is frequently accompanied by nausea and vomiting that may become severe and life-threatening, as in hyperemesis gravidarum (HG), the cause of which is unknown. Growth Differentiation Factor-15 (GDF15), a hormone known to act on the hindbrain to cause emesis, is highly expressed in the placenta and its levels in maternal blood rise rapidly in pregnancy. Variants in the maternal GDF15 gene are associated with HG. Here we report that fetal production of GDF15, and maternal sensitivity to it, both contribute substantially to the risk of HG. We found that the great majority of GDF15 in maternal circulation is derived from the feto-placental unit and that higher GDF15 levels in maternal blood are associated with vomiting and are further elevated in patients with HG. Conversely, we found that lower levels of GDF15 in the non-pregnant state predispose women to HG. A rare C211G variant in GDF15 which strongly predisposes mothers to HG, particularly when the fetus is wild-type, was found to markedly impair cellular secretion of GDF15 and associate with low circulating levels of GDF15 in the non-pregnant state. Consistent with this, two common GDF15 haplotypes which predispose to HG were associated with lower circulating levels outside pregnancy. The administration of a long-acting form of GDF15 to wild-type mice markedly reduced subsequent responses to an acute dose, establishing that desensitisation is a feature of this system. GDF15 levels are known to be highly and chronically elevated in patients with beta thalassemia. In women with this disorder, reports of symptoms of nausea or vomiting in pregnancy were strikingly diminished. Our findings support a causal role for fetal derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by pre-pregnancy exposure to GDF15, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

7.
AAPS PharmSciTech ; 13(4): 1197-211, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22965662

ABSTRACT

Sustained-release matrix tablets based on Eudragit RL and RS were manufactured by injection moulding. The influence of process temperature; matrix composition; drug load, plasticizer level; and salt form of metoprolol: tartrate (MPT), fumarate (MPF) and succinate (MPS) on ease of processing and drug release were evaluated. Formulations composed of 70/30% Eudragit RL/MPT showed the fastest drug release, substituting part of Eudragit RL by RS resulted in slower drug release, all following first-order release kinetics. Drug load only affected drug release of matrices composed of Eudragit RS: a higher MPT concentration yielded faster release rates. Adding triethyl citrate enhanced the processability, but was detrimental to long-term stability. The process temperature and plasticizer level had no effect on drug release, whereas metoprolol salt form significantly influenced release properties. The moulded tablets had a low porosity and a smooth surface morphology. A plasticizing effect of MPT, MPS and MPF on Eudragit RS and Eudragit RL was observed via DSC and DMA. Solubility parameter assessment, thermal analysis and X-ray diffraction demonstrated the formation of a solid solution immediately after production, in which H-bonds were formed between metoprolol and Eudragit as evidenced by near-infrared spectroscopy. However, high drug loadings of MPS and MPF showed a tendency to recrystallise during storage. The in vivo performance of injection-moulded tablets was strongly dependent upon drug loading.


Subject(s)
Delayed-Action Preparations/chemistry , Drug Carriers/chemistry , Metoprolol/chemistry , Tablets/chemistry , Acrylic Resins/chemistry , Biological Availability , Chemistry, Pharmaceutical/methods , Citrates/chemistry , Drug Compounding/methods , Drug Stability , Kinetics , Plasticizers/chemistry , Polymers/chemistry , Porosity , Solubility , Temperature
8.
Nat Med ; 7(5): 575-83, 2001 May.
Article in English | MEDLINE | ID: mdl-11329059

ABSTRACT

Vascular endothelial growth factor (VEGF) stimulates angiogenesis by activating VEGF receptor-2 (VEGFR-2). The role of its homolog, placental growth factor (PlGF), remains unknown. Both VEGF and PlGF bind to VEGF receptor-1 (VEGFR-1), but it is unknown whether VEGFR-1, which exists as a soluble or a membrane-bound type, is an inert decoy or a signaling receptor for PlGF during angiogenesis. Here, we report that embryonic angiogenesis in mice was not affected by deficiency of PlGF (Pgf-/-). VEGF-B, another ligand of VEGFR-1, did not rescue development in Pgf-/- mice. However, loss of PlGF impaired angiogenesis, plasma extravasation and collateral growth during ischemia, inflammation, wound healing and cancer. Transplantation of wild-type bone marrow rescued the impaired angiogenesis and collateral growth in Pgf-/- mice, indicating that PlGF might have contributed to vessel growth in the adult by mobilizing bone-marrow-derived cells. The synergism between PlGF and VEGF was specific, as PlGF deficiency impaired the response to VEGF, but not to bFGF or histamine. VEGFR-1 was activated by PlGF, given that anti-VEGFR-1 antibodies and a Src-kinase inhibitor blocked the endothelial response to PlGF or VEGF/PlGF. By upregulating PlGF and the signaling subtype of VEGFR-1, endothelial cells amplify their responsiveness to VEGF during the 'angiogenic switch' in many pathological disorders.


Subject(s)
Capillary Permeability , Endothelial Growth Factors/physiology , Lymphokines/physiology , Neoplasms, Experimental/blood supply , Neovascularization, Pathologic , Pregnancy Proteins/physiology , Animals , Base Sequence , DNA Primers , Embryonic and Fetal Development , Mice , Placenta Growth Factor , Plasma , Pregnancy Proteins/genetics , Reverse Transcriptase Polymerase Chain Reaction , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors , Wound Healing/physiology
9.
Appl Environ Microbiol ; 76(17): 5902-10, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20639361

ABSTRACT

We performed a microbial community analysis of biofilms inhabiting thermal (35 to 50 degrees C) waters more than 60 m below the ground surface near Acquasanta Terme, Italy. The groundwater hosting the biofilms has 400 to 830 microM sulfide, <10 microM O(2), pH of 6.3 to 6.7, and specific conductivity of 8,500 to 10,500 microS/cm. Based on the results of 16S rRNA gene cloning and fluorescent in situ hybridization (FISH), the biofilms have low species richness, and lithoautotrophic (or possibly mixotrophic) Gamma- and Epsilonproteobacteria are the principle biofilm architects. Deltaproteobacteria sequences retrieved from the biofilms have <90% 16S rRNA similarity to their closest relatives in public databases and may represent novel sulfate-reducing bacteria. The Acquasanta biofilms share few species in common with Frasassi cave biofilms (13 degrees C, 80 km distant) but have a similar community structure, with representatives in the same major clades. The ecological success of Sulfurovumales-group Epsilonproteobacteria in the Acquasanta biofilms is consistent with previous observations of their dominance in sulfidic cave waters with turbulent water flow and high dissolved sulfide/oxygen ratios.


Subject(s)
Bacteria/classification , Bacteria/isolation & purification , Biofilms/growth & development , Biota , Hot Springs/microbiology , Sulfides/analysis , Water/chemistry , Animals , Bacteria/genetics , Cluster Analysis , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Electric Conductivity , In Situ Hybridization, Fluorescence , Italy , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA
10.
Lupus ; 19(2): 130-7, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19919973

ABSTRACT

beta2-glycoprotein I is the best-characterized antigenic target for antiphospholipid autoantibodies. We synthesized a tetrameric conjugate of the domain 1 of beta2-glycoprotein I (LJP 993) aimed at developing the conjugate as a Toleragen to suppress antiphospholipid syndrome. The present studies focused on determining the stability, tissue distribution, plasma concentration-time profile and excretion of the LJP 993 in mice. The stability of LJP 993 in mouse plasma was quantitatively evaluated using strong cation-exchange high performance liquid chromatography. ( 125)I-labeled LJP 993 was intravenously injected to mice, and levels of (125)I-labeled LJP 993 in plasma, tissues, urine and feces were determined at known intervals. Incubation of LJP 993 with mouse serum at 37 degrees C for 8 h resulted in a decrease by 34% of LJP 993 concentration. No degradation fragment was observed during the incubation. After a single intravenous administration of (125)I-LJP 993 (0.5 and 5 mg/kg) to mice, both C(max) and area-under-curve values increased in a dose-proportional manner, and blood radioactivity disappeared in a bi-exponential manner with the distribution half-lives equal to 1.7 min, and the elimination half-lives 188 and 281 min, respectively. The (125)I-LJP 993 was moderately distributed into organs and tissues with the exception that brain level of ( 125)I-LJP 993 was negligible. The major sites of (125)I-LJP 993 uptake were the kidney (at 30 min post dosing), and kidney, lung, liver, heart, spleen, skin, muscle and fat tissues (at 4 h post dosing). Cumulative urinary and fecal radioactivity for 0-48 h post dosing accounted for 44.7% and 4.2% of the administered dose, respectively, with the fast rate of urinal excretion occurring within the first 8 h. In summary, LJP 993 was fairly stable in mouse plasma. After administration to mice, (125)I-LJP 993 was taken up mainly by kidney and then distributed extensively to tissues except brain. Both C(max) and area-under-curve values increased in a dose-proportional manner. It was predominantly excreted in the urine with an elimination half-life longer than 3 h. Kidney is a major route to excrete the tetrameric conjugate.


Subject(s)
Chromatography, High Pressure Liquid/methods , Ethers/pharmacokinetics , Ketones/pharmacokinetics , Animals , Antiphospholipid Syndrome/drug therapy , Area Under Curve , Chromatography, Ion Exchange/methods , Dose-Response Relationship, Drug , Ethers/administration & dosage , Female , Half-Life , Iodine Radioisotopes , Ketones/administration & dosage , Male , Mice , Mice, Inbred BALB C , Tissue Distribution
11.
Placenta ; 30 Suppl A: S43-8, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19081132

ABSTRACT

The pregnancy complications of unexplained intrauterine growth restriction and early onset preeclampsia are thought to share a common aetiology in placental malperfusion secondary to deficient maternal spiral artery conversion. A key question is whether the contrasting clinical manifestations reflect different placental pathologies, or whether they are due to altered maternal responses to a common factor derived from the placenta. Recently, molecular evidence of protein synthesis inhibition secondary to endoplasmic reticulum stress has provided an explanation for the small placental phenotype in both conditions. However, other pathways activated by more severe endoplasmic reticulum stress are only observed in placentas from pregnancies associated with early onset preeclampsia. Here, we review the literature and conclude that there is evidence of greater maternal vascular compromise of the placenta in these cases. We speculate that in cases of normotensive intrauterine growth restriction the placental pathology is centred predominantly around endoplasmic reticulum stress, whereas in cases complicated by preeclampsia oxidative stress is further superimposed. This causes the release of a potent mix of pro-inflammatory cytokines, anti-angiogenic factors and trophoblastic aponecrotic debris into the maternal circulation that causes the peripheral syndrome. Maternal and fetal constitutional factors may modulate how the placenta responds to the maternal vascular insult, and how the mother is affected by the placental factors released. However, the principal conclusion is that the difference between these two conditions lies in the severity of the initiating deficit in spiral arterial conversion, and the relative degrees of endoplasmic reticulum stress and oxidative stress induced in the placenta as a result.


Subject(s)
Fetal Growth Retardation/etiology , Oxidative Stress , Placental Insufficiency/physiopathology , Pre-Eclampsia/physiopathology , Endoplasmic Reticulum/physiology , Female , Humans , Pre-Eclampsia/etiology , Pregnancy , Protein Folding , Signal Transduction/physiology , Uterus/blood supply
12.
Reproduction ; 138(6): 895-902, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19470597

ABSTRACT

During the course of 9 months, the human placenta develops into a highly vascular organ. Vasculogenesis starts during the third week post-conception. Hemangioblastic cell cords differentiate in situ from mesenchymal cells in the villous cores, most probably under the influence of vascular endothelial growth factor (VEGFA) secreted by the overlying trophoblast. The cords elongate through proliferation and cell recruitment, and connect with the vasculature of the developing fetus. A feto-placental circulation starts around 8 weeks of gestation. Elongation of the capillaries outstrips that of the containing villi, leading to looping of the vessels. The obtrusion of both capillary loops and new sprouts results in the formation of terminal villi. Branching and non-branching angiogenesis therefore play key roles in villous morphogenesis throughout pregnancy. Maternal circulating levels of VEGFA and placental growth factor vary across normal pregnancy, and in complicated pregnancies. Determining the impact of these changes on placental angiogenesis is difficult, as the relationship between levels of factors in the maternal circulation and their effects on fetal vessels within the placenta remains unclear. Furthermore, the trophoblast secretes large quantities of soluble receptors capable of binding both growth factors, influencing their bioavailability. Villous endothelial cells are prone to oxidative stress, which activates the apoptotic cascade. Oxidative stress associated with onset of the maternal circulation, and with incomplete conversion of the spiral arteries in pathological pregnancies, plays an important role in sculpting the villous tree. Suppression of placental angiogenesis results in impoverished development of the placenta, leading ultimately to fetal growth restriction.


Subject(s)
Blood Vessels/growth & development , Blood Vessels/physiology , Placenta/blood supply , Placental Circulation/physiology , Animals , Blood Vessels/anatomy & histology , Blood Vessels/ultrastructure , Female , Humans , Models, Biological , Neovascularization, Physiologic/physiology , Placenta/anatomy & histology , Placenta/physiology , Placentation , Pregnancy , Vascular Endothelial Growth Factor A/metabolism , Vascular Endothelial Growth Factor A/physiology
13.
Reproduction ; 138(2): 357-70, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19439560

ABSTRACT

Progesterone is essential for endometrial receptivity in primates. In studies previously performed using global gene profiling based on microarray technology, attempts have been made to identify changes in gene expression between early luteal-phase and mid-luteal-phase endometria. However, the issue of the putative impact of preimplantation embryo-derived signal in the process of endometrial receptivity was missing in the previous studies. In the present study, an attempt has been made to delineate the transcripts profile in implantation-stage endometrium under combinatorial regulation of progesterone and embryo-derived signal in the rhesus monkey. To this effect, we have compared transcript profiles for 409 known genes between control receptive stage (n=13), and mifepristone-induced desynchronized and non-receptive stage (n=12) monkey endometrial samples collected on days 4 (n=12) and 6 (n=13) after ovulation from mated, potential conception cycles, using cDNA arrays containing sequence-verified clones. Statistical analysis of correlation of estimated transcript abundance between arrays and qRT-PCR for nine selected gene products yielded significant (P<0.05) concordance. Of 409 genes, a total of 40 gene transcripts were seen to be affected, nine gene transcripts in endometrial samples were found to progressively increase between days 4 and 6 following mifepristone treatment, while an additional five genes showed differential expression profile depending on the day after treatment. Additionally, different sets of 12 and 14 gene products showed changes in days 4 and 6 post-ovulation samples respectively. A new cohort of 28 gene products in implantation-stage endometrium was seen to be affected by luteal-phase mifepristone.


Subject(s)
Embryo Implantation/drug effects , Endometrium/metabolism , Hormone Antagonists/administration & dosage , Mifepristone/administration & dosage , Transcription, Genetic/physiology , Animals , Female , Gene Expression , Gene Expression Profiling , Hormone Antagonists/pharmacology , Immunohistochemistry , Janus Kinase 1/analysis , Janus Kinase 1/metabolism , Luteal Phase , Macaca mulatta , Mifepristone/pharmacology , Oligonucleotide Array Sequence Analysis , Pregnancy , Progesterone/metabolism , Reverse Transcriptase Polymerase Chain Reaction/methods , STAT3 Transcription Factor/analysis , STAT3 Transcription Factor/metabolism , Transcription, Genetic/drug effects
14.
Science ; 211(4478): 165-7, 1981 Jan 09.
Article in English | MEDLINE | ID: mdl-17757267

ABSTRACT

Systematic variations in annual growth increments, formed over a 16-year period in shells of the marine bivalve mollusc Spisula solidissima, reveal more growth in some years than others. Favorable years are indicated by larger than expected annual growth increments and successful recruitment of juveniles. Variations in the size of growth increments correlate negatively with sea surface temperatures. The results suggest that the annual growth increments in the shells of certain molluscs record changes in the marine environment and may be useful monitors of pollution and indicators of paleotemperatures.

15.
Science ; 231(4733): 46-8, 1986 Jan 03.
Article in English | MEDLINE | ID: mdl-17819230

ABSTRACT

Stable isotopic and shell-growth banding studies of the symbiont-bearing giant clam Tridacna maxima reveal the existence of two growth phases related to sexual maturity that can be discerned in the shells of extinct and extant mollusks. The changeover from the first to second growth phase at an age of approximately 10 years is accompanied by a decrease in rate of calcification and suggests a reordering of energy priorities between biomineralization and reproduction. The carbon-13 to carbon-12 ratio of Tridacna maxima is systematically depleted relative to symbiont-barren mollusks, making it possible to determine the importance of algal-molluscan symbiosis to the functional morphology and paleoecology of mollusks in the geologic record.

16.
Science ; 152(3720): 381-2, 1966 Apr 15.
Article in English | MEDLINE | ID: mdl-17775175

ABSTRACT

In some dogs there are preganglionic fibers leaving the cervical spinal cord through the ventral roots of the lower cervical nerves. When these fibers are stimulated electrically in the anesthetized dog with skeletal muscle paralysis (induced by decamethonium), the effects are vasoconstriction in the front footpad, cardiac acceleration and augmentation, and a rise in arterial blood pressure.

17.
Int J Pharm ; 566: 476-487, 2019 Jul 20.
Article in English | MEDLINE | ID: mdl-31085253

ABSTRACT

Currently in the pharmaceutical industry, continuous manufacturing is an area of significant interest. In particular, hot-melt extrusion (HME) offers many advantages and has been shown to significantly reduce the number of processing steps relative to a conventional product manufacturing line. To control product quality during HME without process interruption, integration of inline analytical technology is critical. Vibrational spectroscopy (Raman, NIR and FT-IR) is often employed and used for real-time measurements because of the non-destructive and rapid nature of these analytical techniques. However, the establishment of reliable Process Analytical Technology (PAT) tools for HME of thermolabile drugs is challenging. Indeed, the Raman effect is inherently weak and might be subject to interference. Moreover, during HME, heating and photodecomposition can occur and disrupt spectra acquisition. The aim of this research article was to explore the use of inline Raman spectroscopy to characterise a thermolabile drug, ramipril (RMP), during continuous HME processing. Offline measurements by HPLC, LC-MS and Raman spectroscopy were used to characterise RMP and its main degradation product, ramipril-diketopiperazine (RMP-DKP, impurity K). A set of HME experiments together with inline Raman spectroscopic analyses were performed. The feasibility of implementing inline Raman spectroscopic analysis to quantify the level of RMP and RMP-DKP in the extrudate was addressed. Two regions in the Raman spectrum were selected to differentiate RMP and RMP-DKP. When regions were combined, a principle component analysis (PCA) model defined by these two main components (PC 1 = 50.1% and PC 2 = 45%) was established. Using HPLC analyses, we were able to confirm that the PC 1 score was attributed to the level of RMP-DKP, and the PC 2 score was related to the RMP drug content. Investigation of the PCA scatterplot indicated that HME processing temperature was not the only factor causing RMP degradation. Additionally, the plasticiser content, feeding speed and screw rotating speed contributed to RMP degradation during HME processing.


Subject(s)
Hot Melt Extrusion Technology , Quality Control , Spectrum Analysis, Raman/methods , Chromatography, High Pressure Liquid , Citrates/chemistry , Drug Combinations , Plasticizers/chemistry , Polymethacrylic Acids/chemistry , Ramipril/chemistry
18.
Int J Pharm ; 545(1-2): 183-196, 2018 Jul 10.
Article in English | MEDLINE | ID: mdl-29730176

ABSTRACT

The purpose of this work was to investigate the application of different advanced continuous processing techniques (hot melt extrusion and spray drying) to the production of fixed-dose combination (FDC) monolithic systems comprising of hydrochlorothiazide and ramipril for the treatment of hypertension. Identical FDC formulations were manufactured by the two different methods and were characterised using powder X-ray diffraction (PXRD) and modulated differential scanning calorimetry (mDSC). Drug dissolution rates were investigated using a Wood's apparatus, while physical stability was assessed on storage under controlled temperature and humidity conditions. Interestingly both drugs were transformed into their amorphous forms when spray dried, however, hydrochlorothiazide was determined, by PXRD, to be partially crystalline when hot melt extruded with either polymer carrier (Kollidon® VA 64 or Soluplus®). Hot melt extrusion was found to result in significant degradation of ramipril, however, this could be mitigated by the inclusion of the plasticizer, polyethylene glycol 3350, in the formulation and appropriate adjustment of processing temperature. The results of intrinsic dissolution rate studies showed that hot-melt extruded samples were found to release both drugs faster than identical formulations produced via spray drying. However, the differences were attributable to the surface roughness of the compressed discs in the Wood's apparatus, rather than solid state differences between samples. After a 60-day stability study spray dried samples exhibited a greater physical stability than the equivalent hot melt extruded samples.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/chemistry , Antihypertensive Agents/chemistry , Diuretics/chemistry , Hot Temperature , Hydrochlorothiazide/chemistry , Ramipril/chemistry , Technology, Pharmaceutical/methods , Calorimetry, Differential Scanning , Crystallography, X-Ray , Drug Carriers , Drug Combinations , Drug Compounding , Drug Liberation , Drug Stability , Kinetics , Microscopy, Electron, Scanning , Particle Size , Plasticizers/chemistry , Polyethylene Glycols/chemistry , Polyvinyls/chemistry , Powder Diffraction , Pyrrolidines/chemistry , Solubility , Surface Properties , Vinyl Compounds/chemistry
19.
Placenta ; 63: 45-52, 2018 03.
Article in English | MEDLINE | ID: mdl-29183631

ABSTRACT

INTRODUCTION: Birth weight to placenta weight (BWPW)-ratio is an indicator of the ability of the placenta to maintain adequate nutrient supply to the fetus. We sought to investigate the relationship between BWPW-ratio with fetal growth, utero-placental Doppler and neonatal and maternal morbidity. METHODS: We studied a group of 3311 women recruited to a prospective cohort study of nulliparous women (Rosie Hospital, Cambridge, UK) who delivered a live born infant at term and whose placental weight and birth weight were known. Ultrasonic indices and BWPW ratio were converted to gestational age adjusted z scores. Analysis of continuous variables was by multivariable linear regression. BWPW ratio was also categorized (lowest or highest quintile, both referent to quintiles 2 to 4) and associations with adverse outcomes analyzed using multivariable logistic regression. RESULTS: Lowest quintile of BWPW-ratio was associated (adjusted odds ratio [95% CI], P) with both neonatal morbidity (1.55 [1.12-2.14], 0.007) and maternal diabetes (1.75 [1.18-2.59], 0.005). Highest quintile of BWPW ratio was associated with a reduced risk of maternal obesity (0.71 [0.53 to 0.95], 0.02) and preeclampsia (0.51 [0.31 to 0.84], 0.008), but higher (adjusted z score [95% CI], P) uterine artery Doppler mean pulsatility index (PI) at 20 weeks of gestation (0.09 [0.01-0.18], 0.04) and umbilical artery Doppler PI at 36 weeks of gestation (0.16 [0.07-0.25], <0.001). CONCLUSION: BWPW-ratio is related to ultrasonic measurements and both neonatal and maternal morbidity. Therefore, this ratio may be an indicative marker of immediate and longer term health risks for an individual.


Subject(s)
Birth Weight/physiology , Parity/physiology , Placenta/anatomy & histology , Adult , Female , Humans , Organ Size/physiology , Placenta/diagnostic imaging , Pregnancy , Prospective Studies , Ultrasonography, Prenatal , Umbilical Arteries/diagnostic imaging , Uterine Artery/diagnostic imaging
20.
J Clin Invest ; 98(2): 482-9, 1996 Jul 15.
Article in English | MEDLINE | ID: mdl-8755660

ABSTRACT

Angiogenesis is important in the pathophysiology of endometriosis, a condition characterized by implantation of ectopic endometrium in the peritoneal cavity. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor involved in physiological and pathological angiogenesis, and elevated levels of VEGF are found in peritoneal fluid of patients with endometriosis. Our aim was to investigate the site of expression and regulation of VEGF in endometriosis. VEGF immunoreactivity was found in tissue macrophages present in ectopic endometrium and in activated peritoneal fluid macrophages. Macrophage activation was highest in women with endometriosis, and media conditioned by peritoneal fluid macrophages from these women caused a VEGF-dependent increase in endothelial cell proliferation above that seen from normal women. Peritoneal fluid macrophages secreted VEGF in response to ovarian steroids, and this secretion was enhanced after activation with lipopolysaccharide. Peritoneal fluid macrophages expressed receptors for steroid hormones. VEGF receptors flt and KDR (kinase domain receptor) were also detected, suggesting autocrine regulation. During the menstrual cycle, expression of flt was constant but that of KDR was increased in the luteal phase, at which time the cells migrated in response to VEGF. KDR expression and the migratory response were significantly higher in patients with endometriosis. This study demonstrates that activated macrophages are a major source of VEGF in endometriosis and that this expression is regulated directly by ovarian steroids.


Subject(s)
Endometriosis/physiopathology , Endothelial Growth Factors/biosynthesis , Endothelium, Vascular/cytology , Estradiol/pharmacology , Lymphokines/biosynthesis , Macrophages, Peritoneal/physiology , Progesterone/pharmacology , Adult , Base Sequence , Biological Assay , Cells, Cultured , Culture Media, Conditioned , DNA Primers , Endometriosis/immunology , Endothelial Growth Factors/analysis , Endothelial Growth Factors/pharmacology , Endothelium, Vascular/drug effects , Female , Flow Cytometry , Humans , Lipopolysaccharides/pharmacology , Lymphokines/analysis , Lymphokines/pharmacology , Macrophage Activation , Macrophages, Peritoneal/drug effects , Molecular Sequence Data , Peritoneal Cavity , Polymerase Chain Reaction , Receptor Protein-Tyrosine Kinases/analysis , Receptor Protein-Tyrosine Kinases/biosynthesis , Receptors, Estrogen/biosynthesis , Receptors, Growth Factor/analysis , Receptors, Growth Factor/biosynthesis , Receptors, Progesterone/biosynthesis , Receptors, Vascular Endothelial Growth Factor , Reference Values , Umbilical Veins , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
SELECTION OF CITATIONS
SEARCH DETAIL