Pharmacological activation of peroxisome proliferator-activated receptor γ (PPAR-γ) protects against hypoxia-associated fetal growth restriction.

The hypoxia of high-altitude (HA) residence increases the risk of intrauterine growth restriction (IUGR) and preeclampsia 3-fold, augmenting perinatal morbidity and mortality and the risk for childhood and adult disease. Currently, no effective therapies exist to prevent these vascular disorders of pregnancy. The peroxisome proliferator-activated receptor γ (PPAR-γ) is an important regulator of uteroplacental vascular development and function and has been implicated in the pathogenesis of IUGR and preeclampsia. Here, we used a model of HA pregnancy in mice to determine whether hypoxia-induced fetal growth restriction reduces placental PPAR-γ protein expression and placental vascularization and, if so, to evaluate the effectiveness of the selective PPAR-γ agonist pioglitazone (PIO) for preventing hypoxia-induced IUGR. Hypoxia resulted in asymmetric IUGR, placental insufficiency, and reduced placental PPAR-γ expression; PIO prevented approximately half of the fetal growth restriction and attenuated placental insufficiency. PIO did not affect fetal growth under normoxia. Although PIO was beneficial for fetal growth, PIO treatment reduced placental vascular density of the labrynthine zone in normoxic and hypoxic (Hx) conditions, and mean vascular area was reduced in the Hx group. Our results suggest that pharmacological PPAR-γ activation is a potential strategy for preventing IUGR in pregnancies complicated by hypoxia, although further studies are needed to identify its likely metabolic or vascular mechanisms.-Lane, S. L., Dodson, R. B., Doyle, A. S., Park, H., Rathi, H., Matarrazo, C. J., Moore, L. G., Lorca, R. A., Wolfson, G. H., Julian, C. G. Pharmacological activation of peroxisome proliferator-activated receptor γ (PPAR-γ) protects against hypoxia-associated fetal growth restriction.

Impact of diet on the persistence of early vascular remodeling and stiffening induced by intrauterine growth restriction and a maternal high-fat diet.

Intrauterine growth restriction (IUGR) and maternal high-fat diet (HFD) independently predispose offspring to hypertension. In a rat model, IUGR more so than maternal HFD increases arterial stiffness with vascular remodeling as early as postnatal day (PND) 21. The trajectory of such early vascular changes remains unknown. We hypothesized that IUGR would increase blood pressure (BP), arterial stiffness, and markers of ongoing detrimental vascular remodeling in adult rats exposed to a maternal HFD regardless of weaning diet. Adult female rats were fed either a regular diet (RD) or an HFD before mating through lactation. IUGR was induced by uterine artery ligation. Offspring were weaned to either a RD or HFD through PND 60. For both control and IUGR rats, this design resulted in the following three diet groups: offspring from RD dams weaned to a RD and offspring from HFD dams weaned to a RD or to an HFD (IHH). In both males and females, only IHH increased systolic BP, but IUGR and HFD both alone and in combination increased arterial stiffness. Aortas contained fewer but thicker elastin bands in IHH rats and IUGR offspring from dams fed an HFD and weaned to a regular diet. IHH increased aortic lysl oxidase protein. In summary, the PND 21 rat mediators of vascular remodeling from IUGR and maternal HFD normalize by PND 60 while changes in elastin and arterial stiffness persist. We speculate that the longer-term risk of hypertension from dietary mediators is augmented by underlying IUGR-induced structural changes to the extracellular matrix.NEW & NOTEWORTHY We report that a combined insult of intrauterine growth restriction and maternal high-fat diet increases the risk of early cardiovascular pathology both independently and in conjunction with a continued high-fat diet in offspring.

Intrauterine growth restriction decreases NF-κB signaling in fetal pulmonary artery endothelial cells of fetal sheep.

Intrauterine growth restriction (IUGR) in premature newborns increases the risk for bronchopulmonary dysplasia, a chronic lung disease characterized by disrupted pulmonary angiogenesis and alveolarization. We previously showed that experimental IUGR impairs angiogenesis; however, mechanisms that impair pulmonary artery endothelial cell (PAEC) function are uncertain. The NF-κB pathway promotes vascular growth in the developing mouse lung, and we hypothesized that IUGR disrupts NF-κB-regulated proangiogenic targets in fetal PAEC. PAECs were isolated from the lungs of control fetal sheep and sheep with experimental IUGR from an established model of chronic placental insufficiency. Microarray analysis identified suppression of NF-κB signaling and significant alterations in extracellular matrix (ECM) pathways in IUGR PAEC, including decreases in collagen 4α1 and laminin α4, components of the basement membrane and putative NF-κB targets. In comparison with controls, immunostaining of active NF-κB complexes, NF-κB-DNA binding, baseline expression of NF-κB subunits p65 and p50, and LPS-mediated inducible activation of NF-κB signaling were decreased in IUGR PAEC. Although pharmacological NF-κB inhibition did not affect angiogenic function in IUGR PAEC, angiogenic function of control PAEC was reduced to a similar degree as that observed in IUGR PAEC. These data identify reductions in endothelial NF-κB signaling as central to the disrupted angiogenesis observed in IUGR, likely by impairing both intrinsic PAEC angiogenic function and NF-κB-mediated regulation of ECM components necessary for vascular development. These data further suggest that strategies that preserve endothelial NF-κB activation may be useful in lung diseases marked by disrupted angiogenesis such as IUGR.

Antenatal Vitamin D Preserves Placental Vascular and Fetal Growth in Experimental Chorioamnionitis Due to Intra-amniotic Endotoxin Exposure.

BACKGROUND: Chorioamnionitis (CA) is associated with a high risk for the development of bronchopulmonary dysplasia (BPD) after preterm birth, but mechanisms that increase susceptibility for BPD and strategies to prevent BPD are uncertain. As a model of CA, antenatal intra-amniotic (IA) endotoxin (ETX) exposure alters placental structure, causes fetal growth restriction, increases perinatal mortality, and causes sustained cardiorespiratory abnormalities throughout infancy. Vitamin D (Vit D) has been shown to have both anti-inflammatory and proangiogenic properties. Antenatal IA treatment with Vit D (1,25-(OH)2D3) during IA ETX exposure improves survival and increases vascular and alveolar growth in infant rats. Whether IA ETX causes decreased placental vascular development and if the protective effects of prenatal Vit D treatment are due to direct effects on the fetus or to improved placental vascular development remain unknown. OBJECTIVE: The objective of this study was to determine if IA ETX impairs placental vascular development and Vit D metabolism, and whether 1,25-(OH)2D3 treatment improves placental vascularity after IA ETX exposure during late gestation in pregnant rats. DESIGN/METHODS: Fetal rats were exposed to ETX (10 mg), ETX + 1,25-(OH)2D3 (1 ng/mL), 1,25-(OH)2D3 (1 ng/mL), or saline (control) via IA injection at E20 and delivered 2 days later. To assess placental vascular development, histologic sections from the placenta were stained for CD31 and vessel density per high power field (HPF) was determined and analyzed using Matlab software. To determine the effects of ETX on placental Vit D metabolism, Vit D receptor (VDR) and activity of the Vit D conversion enzyme, CYP27B1, were assayed from placental homogenates. Angiogenic mediators were measured by reverse transcription polymerase chain reaction by RNA extracted from placental tissue. RESULTS: IA ETX reduced placenta and newborn birth weights by 22 and 20%, respectively, when compared with controls (placental weight: 0.60 vs. 0.47 g; p < 0.0001; birth weight: 4.68 vs. 5.88 g; p < 0.0001). IA 1,25-(OH)2D3 treatment increased birth weight by 12% in ETX-exposed pups (5.25 vs. 4.68 g; p < 0.001). IA ETX decreased placental vessel density by 24% in comparison with controls (1,114 vs. 848 vessels per HPF; p < 0.05). Treatment with IA 1,25-(OH)2D3 increased placenta vessel density twofold after ETX exposure (1,739 vs. 848); p < 0.0001), and increased vessel density compared with saline controls by 56% (1,739 vs. 1,114; p < 0.0001). IA ETX decreased both VDR and CYP27B1 expression by 83 and 35%, respectively (p < 0.01). CONCLUSION: IA ETX decreases placental growth and vessel density and decreases placental VDR and CYP27B1 protein expression, and that antenatal 1,25-(OH)2D3 restores placental weight and vessel density, as well as birth weight. We speculate that 1,25-(OH)2D3 treatment preserves placental function in experimental CA and that these effects may be mediated by increased vascular growth.

Intrauterine growth restriction influences vascular remodeling and stiffening in the weanling rat more than sex or diet.

Intrauterine growth restriction (IUGR) increases the incidence of adult cardiovascular disease (CVD). The sex-specific developmental mechanisms for IUGR-induced and Western high-fat diet (HFD) modification of CVD remain poorly understood. We hypothesized a maternal HFD in the Sprague-Dawley rat would augment IUGR-induced CVD in the offspring through decreased cardiac function and increased extracellular matrix (ECM) remodeling and stiffness in a sex-specific manner. HFD or regular diet (Reg) was given from 5 wk before mating through postnatal day (PND) 21. IUGR was induced by uterine artery ligation at embryonic day 19.5 (term = 21.5 days). At PND 21, echocardiographic assessments were made and carotid arteries tested for vascular compliance using pressure myography. Arterial samples were quantified for ECM constituents or fixed for histologic evaluation. The insult of IUGR (IUGR + Reg and IUGR + HFD) led to increased mechanical stiffness in both sexes (P < 0.05). The combination of IUGR + HFD increased diastolic blood pressure 47% in males (M) and 35% in females (F) compared with the Con + Reg (P < 0.05). ECM remodeling in IUGR + HFD caused fewer (M = -29%, F = -24%) but thicker elastin bands (M = 18%, F = 18%) and increased total collagen (M = 49%, F = 34%) compared with Con + Reg arteries. Remodeling in IUGR + HFD males increased medial collagen and soluble collagen (P < 0.05). Remodeling in IUGR + HFD females increased adventitial collagen and wall thickness (P < 0.05) and decreased matrix metalloproteinase 2 (MMP-2), advanced glycosylation end products (AGE), and receptor AGE (RAGE; P < 0.05). In summary, both IUGR + Reg and IUGR + HFD remodel ECM in PND 21 rats. While IUGR + HFD increases blood pressure, IUGR but not HFD increases vascular stiffness suggesting a specific mechanism of vascular remodeling that can be targeted to limit future disease. NEW & NOTEWORTHY: We report intrauterine growth restriction (IUGR) increases vascular stiffening in both male and female rats through increased collagen content and altered elastin structure more than a high-fat diet (HFD) alone. Our study shows the importance of stiffness supporting the hypothesis that there are physiologic differences and potential windows for early intervention targeting vascular remodeling mechanisms.

Intrauterine endotoxin-induced impairs pulmonary vascular function and right ventricular performance in infant rats and improvement with early vitamin D therapy.

High pulmonary vascular resistance (PVR), proximal pulmonary artery (PA) impedance, and right ventricular (RV) afterload due to remodeling contribute to the pathogenesis and severity of pulmonary hypertension (PH). Intra-amniotic exposure to endotoxin (ETX) causes sustained PH and high mortality in rat pups at birth, which are associated with impaired vascular growth and RV hypertrophy in survivors. Treatment of ETX-exposed pups with antenatal vitamin D (vit D) improves survival and lung growth, but the effects of ETX exposure on RV-PA coupling in the neonatal lung are unknown. We hypothesized that intrauterine ETX impairs RV-PA coupling through sustained abnormalities of PA stiffening and RV performance that are attenuated with vit D therapy. Fetal rats were exposed to intra-amniotic injections of ETX, ETX+vit D, or saline at 20 days gestation (term = 22 days). At postnatal day 14, pups had pressure-volume measurements of the RV and isolated proximal PA, respectively. Lung homogenates were assayed for extracellular matrix (ECM) composition by Western blot. We found that ETX lungs contain decreased α-elastin, lysyl oxidase, collagen I, and collagen III proteins (P < 0.05) compared control and ETX+vit D lungs. ETX-exposed animals have increased RV mechanical stroke work (P < 0.05 vs. control and ETX+vit D) and elastic potential energy (P < 0.05 vs. control and ETX+vit D). Mechanical stiffness and ECM remodeling are increased in the PA (P < 0.05 vs. control and ETX+vit D). We conclude that intrauterine exposure of fetal rats to ETX during late gestation causes persistent impairment of RV-PA coupling throughout infancy that can be prevented with early vit D treatment.

Chronic intrauterine pulmonary hypertension increases main pulmonary artery stiffness and adventitial remodeling in fetal sheep.

Persistent pulmonary hypertension of the newborn (PPHN) is a clinical syndrome that is characterized by high pulmonary vascular resistance due to changes in lung vascular growth, structure, and tone. PPHN has been primarily considered as a disease of the small pulmonary arteries (PA), but proximal vascular stiffness has been shown to be an important predictor of morbidity and mortality in other diseases associated with pulmonary hypertension (PH). The objective of this study is to characterize main PA (MPA) stiffness in experimental PPHN and to determine the relationship of altered biomechanics of the MPA with changes in extracellular matrix (ECM) content and orientation of collagen and elastin fibers. MPAs were isolated from control and PPHN fetal sheep model and were tested by planar biaxial testing to measure stiffness in circumferential and axial vessel orientations. Test specimens were fixed for histological assessments of the vascular wall ECM constituents collagen and elastin. MPAs from PPHN sheep had increased mechanical stiffness (P < 0.05) and altered ECM remodeling compared with control MPA. A constitutive mathematical model and histology demonstrated that PPHN vessels have a smaller contribution of elastin and a greater role for collagen fiber engagement compared with the control arteries. We conclude that exposure to chronic hemodynamic stress in late-gestation fetal sheep increases proximal PA stiffness and alters ECM remodeling. We speculate that proximal PA stiffness further contributes to increased right ventricular impedance in experimental PPHN, which contributes to abnormal transition of the pulmonary circulation at birth.

Thoracic and abdominal aortas stiffen through unique extracellular matrix changes in intrauterine growth restricted fetal sheep.

Intrauterine growth restriction (IUGR) is a fetal complication of pregnancy epidemiologically linked to cardiovascular disease in the newborn later in life. However, the mechanism is poorly understood with very little research on the vascular structure and function during development in healthy and IUGR neonates. Previously, we found vascular remodeling and increased stiffness in the carotid and umbilical arteries, but here we examine the remodeling and biomechanics in the larger vessels more proximal to the heart. To study this question, thoracic and abdominal aortas were collected from a sheep model of placental insufficiency IUGR (PI-IUGR) due to exposure to elevated ambient temperatures. Aortas from control (n = 12) and PI-IUGR fetuses (n = 10) were analyzed for functional biomechanics and structural remodeling. PI-IUGR aortas had a significant increase in stiffness (P < 0.05), increased collagen content (P < 0.05), and decreased sulfated glycosaminoglycan content (P < 0.05). Our derived constitutive model from experimental data related increased stiffness to reorganization changes of increased alignment angle of collagen fibers and increased elastin (P < 0.05) in the thoracic aorta and increased concentration of collagen fibers in the abdominal aorta toward the circumferential direction verified through use of histological techniques. This fetal vascular remodeling in PI-IUGR may set the stage for possible altered growth and development and help to explain the pathophysiology of adult cardiovascular disease in previously IUGR individuals.

Large artery stiffening and mortality in a rat model of early vascular remodeling induced by intrauterine growth restriction and a high-fat diet.

Intrauterine growth restriction (IUGR) and exposure to a high-fat diet (HFD) independently increase the risk of cardiovascular disease (CVD) and hyperlipidemia. In our previous studies, IUGR increased blood pressure and promoted vascular remodeling and stiffness in early life, a finding that persisted and was augmented by a maternal HFD through postnatal day (PND) 60. The impact of these findings with aging and the development of hyperlipidemia and atherosclerosis remain unknown. We hypothesized that the previously noted impact of IUGR on hypertension, vascular remodeling, and hyperlipidemia would persist. Adult female rats were fed either a regular diet (RD) or high fat diet (HFD) prior to conception through lactation. IUGR was induced by uterine artery ligation. Offspring were weaned to either RD or HFD through PND 365. For both control (C) and IUGR (I) and rats, this resulted in the following six groups per sex: offspring from RD dams weaned to an RD (CRR and IRR), or offspring from HFD dams weaned to either an RD (CHR and IHR) or to an HFD (CHH and IHH). IHH male and female rats had increased large artery stiffness, a suggestion of fatty streaks in the aorta, and persistent decreased elastin and increased collagen in the aorta and carotid arteries. Post-weaning HFD intake increased blood lipids regardless of IUGR status. IUGR increased HFD-induced mortality. We speculate that HFD-induced risk of CVD and mortality is potentiated by developmental programming of the ECM.

Pituitary receptor site blockade by a gonadotropin-releasing hormone antagonist in vivo: mechanism of action.

Administration of a potent gonadotropin-releasing hormone (GnRH) antagonist [Nac-L-Ala1,pCl-D-Phe2,D-Trp3,6]GnRH as a single subcutaneous injection to castrated adult male rats reduced, by more than 90 percent, both serum luteinizing hormone concentrations and specific pituitary GnRH receptor binding. This effect persisted for 24 hours. The dissociation rate of the antagonist from pituitary membrane homogenates was fourfold slower than the dissociation rate of a potent agonist. The prolonged in vivo inhibition of pituitary GnRH receptor binding and luteinizing hormone secretion by the GnRH antagonist may be mediated by the slower dissociation rate of the antagonist from its specific pituitary membrane receptor site.

Complete genome sequence of Treponema pallidum, the syphilis spirochete.

The complete genome sequence of Treponema pallidum was determined and shown to be 1,138,006 base pairs containing 1041 predicted coding sequences (open reading frames). Systems for DNA replication, transcription, translation, and repair are intact, but catabolic and biosynthetic activities are minimized. The number of identifiable transporters is small, and no phosphoenolpyruvate:phosphotransferase carbohydrate transporters were found. Potential virulence factors include a family of 12 potential membrane proteins and several putative hemolysins. Comparison of the T. pallidum genome sequence with that of another pathogenic spirochete, Borrelia burgdorferi, the agent of Lyme disease, identified unique and common genes and substantiates the considerable diversity observed among pathogenic spirochetes.

Complete genome sequence of a virulent isolate of Streptococcus pneumoniae.

The 2,160,837-base pair genome sequence of an isolate of Streptococcus pneumoniae, a Gram-positive pathogen that causes pneumonia, bacteremia, meningitis, and otitis media, contains 2236 predicted coding regions; of these, 1440 (64%) were assigned a biological role. Approximately 5% of the genome is composed of insertion sequences that may contribute to genome rearrangements through uptake of foreign DNA. Extracellular enzyme systems for the metabolism of polysaccharides and hexosamines provide a substantial source of carbon and nitrogen for S. pneumoniae and also damage host tissues and facilitate colonization. A motif identified within the signal peptide of proteins is potentially involved in targeting these proteins to the cell surface of low-guanine/cytosine (GC) Gram-positive species. Several surface-exposed proteins that may serve as potential vaccine candidates were identified. Comparative genome hybridization with DNA arrays revealed strain differences in S. pneumoniae that could contribute to differences in virulence and antigenicity.

Complete genome sequence of Neisseria meningitidis serogroup B strain MC58.

The 2,272,351-base pair genome of Neisseria meningitidis strain MC58 (serogroup B), a causative agent of meningitis and septicemia, contains 2158 predicted coding regions, 1158 (53.7%) of which were assigned a biological role. Three major islands of horizontal DNA transfer were identified; two of these contain genes encoding proteins involved in pathogenicity, and the third island contains coding sequences only for hypothetical proteins. Insights into the commensal and virulence behavior of N. meningitidis can be gleaned from the genome, in which sequences for structural proteins of the pilus are clustered and several coding regions unique to serogroup B capsular polysaccharide synthesis can be identified. Finally, N. meningitidis contains more genes that undergo phase variation than any pathogen studied to date, a mechanism that controls their expression and contributes to the evasion of the host immune system.

Genome sequence of the radioresistant bacterium Deinococcus radiodurans R1.

The complete genome sequence of the radiation-resistant bacterium Deinococcus radiodurans R1 is composed of two chromosomes (2,648,638 and 412,348 base pairs), a megaplasmid (177,466 base pairs), and a small plasmid (45,704 base pairs), yielding a total genome of 3,284, 156 base pairs. Multiple components distributed on the chromosomes and megaplasmid that contribute to the ability of D. radiodurans to survive under conditions of starvation, oxidative stress, and high amounts of DNA damage were identified. Deinococcus radiodurans represents an organism in which all systems for DNA repair, DNA damage export, desiccation and starvation recovery, and genetic redundancy are present in one cell.

A single fast radio burst localized to a massive galaxy at cosmological distance.

Fast radio bursts (FRBs) are brief radio emissions from distant astronomical sources. Some are known to repeat, but most are single bursts. Nonrepeating FRB observations have had insufficient positional accuracy to localize them to an individual host galaxy. We report the interferometric localization of the single-pulse FRB 180924 to a position 4 kiloparsecs from the center of a luminous galaxy at redshift 0.3214. The burst has not been observed to repeat. The properties of the burst and its host are markedly different from those of the only other accurately localized FRB source. The integrated electron column density along the line of sight closely matches models of the intergalactic medium, indicating that some FRBs are clean probes of the baryonic component of the cosmic web.

An estrogen-inducible protein binds specifically to a sequence in the 3' untranslated region of estrogen-stabilized vitellogenin mRNA.

The 3' untranslated region (3'-UTR) has been implicated in the estrogen stabilization of hepatic Xenopus laevis vitellogenin mRNA. We used RNA gel mobility shift assays to demonstrate that Xenopus liver contains a factor which binds with very high specificity to a segment of the 3'-UTR of vitellogenin B1 and B2 mRNAs. We detected a single high-affinity binding site in the vitellogenin mRNA 3'-UTR and localized the binding site to a 27-nucleotide region. Since binding was abolished by proteinase K digestion, at least a component of the factor is a protein. Following estrogen administration, binding was induced approximately four- to fivefold in extracts from liver polysomes. The hepatic vitellogenin mRNA-binding protein was found in both polysomes and cytosol. Since the protein was also estrogen inducible in cytosol, this represents a genuine induction, not simply recruitment of the cytosolic protein into polysomes. UV cross-linking studies with the 27-nucleotide recognition sequence revealed bands corresponding to bound proteins with apparent molecular weights of 71,000 and 141,000. This appears to be the first example of steroid hormone-inducible proteins binding to an mRNA 3'-UTR. Its induction by estrogen and its sequence-specific binding to a region of vitellogenin mRNA important in estrogen-mediated stabilization suggest that the protein may play a role in the regulation of mRNA stability.

In vitro genetic analysis of the RNA binding site of vigilin, a multi-KH-domain protein.

The function(s) and RNA binding properties of vigilin, a ubiquitous protein with 14 KH domains, remain largely obscure. We recently showed that vigilin is the estrogen-inducible protein in polysome extracts which binds specifically to a segment of the 3' untranslated region (UTR) of estrogen-stabilized vitellogenin mRNA. In order to identify consensus mRNA sequences and structures important in binding of vigilin to RNA, before vigilin was purified, we developed a modified in vitro genetic selection protocol. We subsequently validated our selection procedure, which employed crude polysome extracts, by testing natural and in vitro-selected RNAs with purified recombinant vigilin. Most of the selected up-binding mutants exhibited hypermutation of G residues leading to a largely unstructured, single-stranded region containing multiple conserved (A)nCU and UC(A)n motifs. All eight of the selected down-binding mutants contained a mutation in the sequence (A)nCU. Deletion analysis indicated that approximately 75 nucleotides are required for maximal binding. Using this information, we predicted and subsequently identified a strong vigilin binding site near the 3' end of human dystrophin mRNA. RNA sequences from the 3' UTRs of transferrin receptor and estrogen receptor, which lack strong homology to the selected sequences, did not bind vigilin. These studies describe an aproach to identifying long RNA binding sites and describe sequence and structural requirements for interaction of vigilin with RNAs.

Dynamic Changes in Aortic Vascular Stiffness in Patients Bridged to Transplant With Continuous-Flow Left Ventricular Assist Devices.

OBJECTIVES: The aim of this study was to measure aortic vascular stiffness from orthotopic heart transplant (OHT) patients exposed to varying types of flow as a result of the presence or absence of left ventricular assist device (LVAD) support pre-OHT. BACKGROUND: The effects of continuous-flow LVADs (CF-LVADs) on vascular properties are unknown, but may contribute to the pathophysiology of CF-LVAD complications such as stroke, hypertension, and bleeding. METHODS: Echocardiograms were reviewed from 172 OHT patients immediately before LVAD and at 3 time points post-OHT: baseline, 6 months, and 1 year. For each study, pulse pressure and aortic end-systolic and end-diastolic dimensions were used to calculate aortic strain, distensibility, and stiffness index. Patients were categorized into 3 groups based on the presence or absence of a LVAD and a pulse pre-OHT: No LVAD (n = 111), LVAD No Pulse (n = 30), and LVAD With Pulse (n = 31). RESULTS: The aortic stiffness index among LVAD No Pulse patients increased from 2.8 ± 1.1 pre-CF-LVAD to 10.9 ± 4.7 immediately post-OHT (p < 0.001). This aortic stiffness index was also significantly higher compared with No LVAD (3.4 ± 1.1; p < 0.001) and LVAD With Pulse (3.7 ± 1.4; p < 0.001) immediately post-OHT with attenuation of these differences by 1 year post-OHT. Similar findings were noted for the other indices of aortic stiffness. CONCLUSIONS: Aortic stiffness is markedly increased immediately post-OHT among patients bridged with CF-LVADs, with attenuation of this increased stiffness over the first year after transplant. These results suggest that aortic vascular properties are dynamic and may be influenced by alterations in flow pulsatility. As more patients are supported with CF-LVADs and as newer pump technology attempts to modulate pulsatility, further research examining the role of alterations in flow patterns on vascular function and the potential resultant systemic sequelae are needed.

Genome sequences of Chlamydia trachomatis MoPn and Chlamydia pneumoniae AR39.

The genome sequences of Chlamydia trachomatis mouse pneumonitis (MoPn) strain Nigg (1 069 412 nt) and Chlamydia pneumoniae strain AR39 (1 229 853 nt) were determined using a random shotgun strategy. The MoPn genome exhibited a general conservation of gene order and content with the previously sequenced C.trachomatis serovar D. Differences between C.trachomatis strains were focused on an approximately 50 kb 'plasticity zone' near the termination origins. In this region MoPn contained three copies of a novel gene encoding a >3000 amino acid toxin homologous to a predicted toxin from Escherichia coli O157:H7 but had apparently lost the tryptophan biosyntheis genes found in serovar D in this region. The C. pneumoniae AR39 chromosome was >99.9% identical to the previously sequenced C.pneumoniae CWL029 genome, however, comparative analysis identified an invertible DNA segment upstream of the uridine kinase gene which was in different orientations in the two genomes. AR39 also contained a novel 4524 nt circular single-stranded (ss)DNA bacteriophage, the first time a virus has been reported infecting C. pneumoniae. Although the chlamydial genomes were highly conserved, there were intriguing differences in key nucleotide salvage pathways: C.pneumoniae has a uridine kinase gene for dUTP production, MoPn has a uracil phosphororibosyl transferase, while C.trachomatis serovar D contains neither gene. Chromosomal comparison revealed that there had been multiple large inversion events since the species divergence of C.trachomatis and C.pneumoniae, apparently oriented around the axis of the origin of replication and the termination region. The striking synteny of the Chlamydia genomes and prevalence of tandemly duplicated genes are evidence of minimal chromosome rearrangement and foreign gene uptake, presumably owing to the ecological isolation of the obligate intracellular parasites. In the absence of genetic analysis, comparative genomics will continue to provide insight into the virulence mechanisms of these important human pathogens.

Administration of 6-methoxybenzoxazolinone (MBOA) does not augment ovulatory responses in St. Croix White ewes superovulated with PMSG.

The objective of this investigation was to examine the effects of 6-methoxy-benzoxazolinone (MBOA), a plant compound that resembles melatonin and alters ovarian function in rodents, in combination with PMSG on superovulatory responses in the cycling ewe. In Experiment I, St. Croix White ewes (n = 44) were synchronized (intra-vaginal progestin sponge) for 14days followed by hCG (750 IU) at 1 day after sponge removal (day 0). Ewes were assigned to one of six treatments administered on day -1: Control (no PMSG or MBOA; n = 7); PMSG (1000 IU i.m.; n = 7); Low MBOA (0.43 mg/kg i.m.; n = 7); High MBOA (1.15 mg/kg i.m.; n = 7); Low MBOA + PMSG (n = 8); High MBOA + PMSG (n = 8). In Experiment II, St. Croix White ewes (n = 24) were synchronized (progestin CIDR) for 14 days followed by hCG on day 1 after CIDR removal (day 0). Ewes were assigned to one of three treatments administered on day -1: Control (n = 8); PMSG (n = 8); Low MBOA+PMSG (n = 8). Laparoscopy was performed on day 9 to assess numbers of corpora lutea (CL) and visible follicles on each ovary. Blood samples were collected on day -13, -1, 0, 1, and days 6 or 7-12 for analysis of serum progesterone (P4) by RIA. Treatment groups receiving PMSG (alone or with MBOA) exhibited greater (P < 0.05) serum concentrations of P4 post-synchrony than Control and MBOA-only groups. Ovulation rate was lower (P < 0.05) for Control and MBOA-only treated ewes than ewes receiving PMSG. Ovulation rate in ewes treated with MBOA alone was similar (P > 0.10) to Controls, and PMSG treatment alone did not differ (P > 0.10) from MBOA + PMSG treatment. Ewes treated with PMSG alone did not differ (P > 0.10) in follicle number from High MBOA + PMSG treated ewes, however, Low MBOA + PMSG treated ewes had greater numbers of follicles at day 9 (P < 0.05) than the PMSG or High MBOA + PMSG groups in Experiment I; although, this was not replicated in Experiment II with numbers of follicles in the Low MBOA + PMSG group being similar (P > 0.10) to PMSG alone. In summary, the addition of MBOA in combination with PMSG as part of a synchronization-superovuation protocol in the ewe did not increase ovulation rate.