DNA Sequence Analysis of an Inversion Hot Spot in Lobeliaceae Plastomes.

The evolution of plastid genomes (plastomes) in land plants is typically conservative, with extensive structural rearrangements present in only a few groups. Early Southern blot analysis identified two Lobelia species that minimally required deletion of the plastid gene accD and five inversions to account for their plastome arrangement relative to the ancestral organization. Sixty alternative 5-step inversion scenarios could account for the observed arrangement, but only one scenario was consistent with the criterion of 'common cause' attributable to a putative rearrangement hot spot at the accD deletion-site. Plastome sequencing demonstrated that this previously hypothesized inversion order is historically accurate. Detailed reconstructions of the ancestral plastome organization before and after each inversion are presented herein. Stem-loop and disruption-rescue models were evaluated for each inversion. One inversion has an obvious stem-loop basis, but the other four inversions were primarily caused by serial insertion of foreign (extra-plastid) DNA bearing large open-reading frames that disrupted plastome organization at the accD deletion-site, and complete plastomes were rescued by seemingly arbitrary ligation or fortuitous recombination at the other inversion endpoint. Transposed copies of DNA segments from elsewhere in the plastome are frequently inserted at inversion junctions, and four junctions are consistent with the stem-loop ligation model.

Do Genetic Drift and Gene Flow Affect the Geographic Distribution of Female Plants in Gynodioecious Lobelia siphilitica?

Variation in population sex ratio is particularly pronounced in gynodioecious angiosperms. Extremely high female frequencies in gynodioecious populations cannot be readily explained by selective forces alone. To assess the contributions of drift and gene flow to extreme sex-ratio variation, we documented sex ratio and population size in 92 populations of Lobelia siphilitica across its range and genotyped plants using plastid and nuclear genetic markers. Similarity in spatial patterns of genetic and demographic variables may suggest that drift and/or gene flow have contributed to population sex-ratio variation in L. siphilitica. We found strong spatial structuring of extremely high female frequencies: populations with >50% female plants are restricted to the south−central portion of the range. However, we did not detect any spatial structuring in population size nor metrics of genetic diversity, suggesting that extreme variation in female frequency is not strongly affected by drift or gene flow. Extreme sex-ratio variation is frequently observed in gynodioecious plants, but its causes are difficult to identify. Further investigation into mechanisms that create or maintain the spatial structure of sex ratios in gynodioecious species will provide much needed insight.

Duplication and expression patterns of CYCLOIDEA-like genes in Campanulaceae.

BACKGROUND: CYCLOIDEA (CYC)-like transcription factors pattern floral symmetry in most angiosperms. In core eudicots, two duplications led to three clades of CYC-like genes: CYC1, CYC2, and CYC3, with orthologs of the CYC2 clade restricting expression dorsally in bilaterally symmetrical flowers. Limited data from CYC3 suggest that they also play a role in flower symmetry in some asterids. We examine the evolution of these genes in Campanulaceae, a group that contains broad transitions between radial and bilateral floral symmetry and 180° resupination (turning upside-down by twisting pedicle). RESULTS: We identify here all three paralogous CYC-like clades across Campanulaceae. Similar to other core eudicots, we show that CamCYC2 duplicated near the time of the divergence of the bilaterally symmetrical and resupinate Lobelioideae. However, in non-resupinate, bilaterally symmetrical Cyphioideae, CamCYC2 appears to have been lost and CamCYC3 duplicated, suggesting a novel genetic basis for bilateral symmetry in Cyphioideae. We additionally, utilized qRT-PCR to examine the correlation between CYC-like gene expression and shifts in flower morphology in four species of Lobelioideae. As expected, CamCYC2 gene expression was dorsoventrally restricted in bilateral symmetrical flowers. However, because Lobelioideae have resupinate flowers, both CamCYC2A and CamCYC2B are highly expressed in the finally positioned ventral petal lobes, corresponding to the adaxial side of the flower relative to meristem orientation. CONCLUSIONS: Our sequences across Campanulaceae of all three of these paralogous groups suggests that radially symmetrical Campanuloideae duplicated CYC1, Lobelioideae duplicated CYC2 and lost CYC3 early in their divergence, and that Cyphioideae lost CYC2 and duplicated CYC3. This suggests a dynamic pattern of duplication and loss of major floral patterning genes in this group and highlights the first case of a loss of CYC2 in a bilaterally symmetrical group. We illustrate here that CYC expression is conserved along the dorsoventral axis of the flower even as it turns upside-down, suggesting that at least late CYC expression is not regulated by extrinsic factors such as gravity. We additionally show that while the pattern of dorsoventral expression of each paralog remains the same, CamCYC2A is more dominant in species with shorter relative finally positioned dorsal lobes, and CamCYC2B is more dominant in species with long dorsal lobes.

The East Asian origin of the giant lobelias.

PREMISE OF THE STUDY: Rapid radiations are difficult to reconstruct when organismal diversification and biogeographic movement outpace the evolution of genes typically used in phylogenetic analyses. The 125 kb of unique sequence from complete plastid genomes (= plastomes) largely solves the molecular sampling problem, and taxon sampling that triangulates the base of each major subclade largely solves the long-branch attraction problem. This combination of molecular and phylogenetic sampling is used to reconstruct the cosmopolitan radiation of lobeliads, with special focus on the origin of the giant lobelias. METHODS: An alignment of 18 previously generated and 61 new plastomes was analyzed to produce the phylogenetic estimate upon which the biogeographic reconstruction was based. KEY RESULTS: Originating in southern Africa, the Lobeliaceae underwent a spectacular cosmopolitan radiation about 20 million years ago. One lineage colonized Madagascar and eastern Asia, which was the source area for the evolution of the giant lobelias. A second lineage colonized the Mediterranean and North America, in quick succession. South America and Australia were also colonized from South Africa, most likely as independent events, but detailed biogeographic reconstruction is limited by inferred extinction events. The south Pacific segregate genera Apetahia and Sclerotheca are inferred to have Hawaiian ancestry. The East African radiation independently reached Ethiopia, West Africa, and Brazil. CONCLUSIONS: With adequate molecular and taxon sampling, many details of rapid radiations can be accurately inferred. However, not all lineages survived, and analyses of extant species cannot recover details that have been lost due to extinction.

The dynamic history of plastid genomes in the Campanulaceae sensu lato is unique among angiosperms.

Why have some plants lost the organizational stability in plastid genomes (plastomes) that evolved in their algal ancestors? During the endosymbiotic transformation of a cyanobacterium into the eukaryotic plastid, most cyanobacterial genes were transferred to the nucleus or otherwise lost from the plastome, and the resulting plastome architecture in land plants confers organizational stability, as evidenced by the conserved gene order among bryophytes and lycophytes, whereas ferns, gymnosperms, and angiosperms share a single, 30-kb inversion. Although some additional gene losses have occurred, gene additions to angiosperm plastomes were previously unknown. Plastomes in the Campanulaceae sensu lato have incorporated dozens of large ORFs (putative protein-coding genes). These insertions apparently caused many of the 125+ large inversions now known in this small eudicot clade. This phylogenetically restricted phenomenon is not biogeographically localized, which indicates that these ORFs came from the nucleus or (less likely) a cryptic endosymbiont.

Horizontal transfer of entire genomes via mitochondrial fusion in the angiosperm Amborella.

We report the complete mitochondrial genome sequence of the flowering plant Amborella trichopoda. This enormous, 3.9-megabase genome contains six genome equivalents of foreign mitochondrial DNA, acquired from green algae, mosses, and other angiosperms. Many of these horizontal transfers were large, including acquisition of entire mitochondrial genomes from three green algae and one moss. We propose a fusion-compatibility model to explain these findings, with Amborella capturing whole mitochondria from diverse eukaryotes, followed by mitochondrial fusion (limited mechanistically to green plant mitochondria) and then genome recombination. Amborella's epiphyte load, propensity to produce suckers from wounds, and low rate of mitochondrial DNA loss probably all contribute to the high level of foreign DNA in its mitochondrial genome.

High uterine contraction rates in births with normal and abnormal umbilical artery gases.

OBJECTIVE: To determine if the incidence of high contraction (HC) rates and associated decelerations were different in term births with metabolic acidemia (MA) compared to those with normal gases (N) over the last 4 h of labor. METHODS: MA included 316 babies with cord base deficits (BD) over 12 mmol/L N - 3,320 babies with BD under 8 mmol/L. HC rates were defined as >5/10 min. RESULTS: One or more episodes of HC occurred in 43.7% of MA and 36.6% of N. (p = 0.015) In both groups the HC rates rose from about 1 in 30 patients at the beginning to 1 in 7 to 9 patients at the end. MA showed a different transition of the deceleration response over time. At the beginning the average ratio of decelerations to uterine contractions was similar in both groups but over the final 140 min MA showed a consistently higher ratio. CONCLUSIONS: Although HC rates were more frequent in the MA, it was not uncommon in N. On average MA showed more decelerations at every level of contractions and had a persistently higher level of decelerations per contraction for more than 2 h before birth.

Implementation of a system-wide policy for labor induction.

Standardization of key clinical protocols and policies in the inpatient obstetric setting has the potential to improve care processes, ultimately resulting in better patient outcomes and decreased professional liability. Increasingly hospitals and healthcare systems are realizing benefits with adoption of standardization as a strategy for quality care improvement. We describe successful system-wide development and implementation of a policy for labor induction including avoidance of elective births before 39 completed weeks of gestation and standardization of various aspects of the labor induction process, with the goal of providing safer care.

Rapid radiation of Impatiens (Balsaminaceae) during Pliocene and Pleistocene: result of a global climate change.

Impatiens comprises more than 1000 species and is one of the largest genera of flowering plants. The genus has a subcosmopolitan distribution, yet most of its evolutionary history is unknown. Diversification analyses, divergence time estimates and historical biogeography, illustrated that the extant species of Impatiens originated in Southwest China and started to diversify in the Early Miocene. Until the Early Pliocene, the net diversification rate within the genus was fairly slow. Since that time, however, approximately 80% of all Impatiens lineages have originated. This period of rapid diversification coincides with the global cooling of the Earth's climate and subsequent glacial oscillations. Without this accelerated diversification rate, Impatiens would only have contained 1/5th of its current number of species, thereby indicating the rapid radiation of the genus.

Clinical outcomes of unstable pelvic fractures in skeletally immature patients.

BACKGROUND: The orthopaedic literature contains few studies evaluating the long-term outcomes of unstable pelvic fractures in skeletally immature patients. The purpose of this study was to determine the factors that may influence the clinical and functional outcomes of such fractures. METHODS: A retrospective review of all patients with open triradiate cartilages and an unstable pelvic (Tile type-B or C) fracture treated, from 1986 to 2000, at one of two level-I trauma centers was performed. Patients were evaluated with a review of their medical records, the Modified Injury Severity Score (MISS), standardized physical examination, standardized radiographic evaluation, and the Short Musculoskeletal Function Assessment Questionnaire (SMFA). The outcomes were then used to assess the difference between patients who had been treated operatively and those who had been treated nonoperatively. RESULTS: Of 230 pelvic fractures treated during the study period, twenty-three in twenty-three patients were unstable. Of the twenty-three patients, twenty, with a mean age of 9.5 years at the time of injury, were evaluated. The mean duration of follow-up was 6.5 years. There were four type-B and sixteen type-C fractures according to the Tile classification system. The four patients with a type-B fracture had a mean of 1.4 cm of pelvic asymmetry at the time of union and the last follow-up, whereas the sixteen patients with a type-C fracture had a mean of 1.5 cm of pelvic asymmetry at those times. Pelvic asymmetry did not remodel even in younger patients. Eighteen patients were treated operatively with external fixation, internal fixation, or a combination of both, and pelvic asymmetry of < or =1 cm was achieved in ten of them. Patients who had < or =1 cm of pelvic asymmetry had no lumbar or sacroiliac pain, no or mild sacroiliac tenderness, no Trendelenburg sign, no lumbar scoliosis, and lower (better) bother and dysfunction scores on the SMFA compared with patients with more pelvic asymmetry. All patients with > or =1.1 cm of pelvic asymmetry had three or more of the following: nonstructural scoliosis, lumbar pain, a Trendelenburg sign, or sacroiliac joint tenderness and pain. Patients with fewer associated injuries and pelvic asymmetry of < or =1 cm had better clinical results. CONCLUSIONS: Unstable pelvic fractures in children can result in long-term morbidity and functional problems. Fractures associated with > or =1.1 cm of pelvic asymmetry following closed reduction should be treated with open reduction and internal or external fixation in order to improve alignment and the long-term functional outcome.

Influence of surface hardener on gypsum abrasion resistance and water sorption.

STATEMENT OF PROBLEM: Abrasion is a major concern when gypsum products are used for dies, leading to the frequent recommendation that surface hardeners should be used before waxing or scanning. PURPOSE: This study evaluated abrasion resistance and water sorption with 4 commonly used gypsum die materials with and without the application of surface die hardeners. MATERIAL AND METHODS: Three ADA Type IV (Vel-Mix, ResinRock, and Silky-Rock) and 1 Type V die material (Die-Keen) were evaluated for abrasion resistance after application of 2 surface hardeners (Permabond 910 cyanoacrylate and Clear Coat). Thirty specimens of each material were fabricated using an impression of a standard brass die machined with 1-mm high ridges, sloped 45 degrees. Gypsum materials were mixed according to manufacturers' recommendations and allowed to set 1 hour before separating. All replicated dies were allowed to bench set for 14 days before testing. One hour before testing, specimens were arbitrarily assigned to 1 of 3 treatment subgroups (n=10/group): no treatment (control), coated with Permabond 910, or coated with Clear Coat. In the coated groups, die hardener was painted over the grooves and air dried. Abrasion resistance (measured by weight loss) was evaluated using a reciprocal abrasion device in which a stylus applied a 50-g mass perpendicular to the ridges. Mass loss was determined using an analytical balance before and after each test cycle. Five sets of 20 unidirectional passes were made on each specimen. A scanning electron microscope was used to evaluate the surface of specimens in each treatment subgroup. Water sorption was also evaluated using 2 Type IV (Silky-Rock, ResinRock) and 1 Type III (Microstone) gypsum materials. Specimen dies were separated 1 hour after pouring the impression and allowed to bench set 1 week before testing. Five specimens from each material group received a coating of a surface hardener 1 hour before testing. Specimens were placed in distilled water for 15 minutes and differences in mass were determined using an analytical balance before and after each test. A 2-way analysis of variance was completed followed by a Tukey post hoc test (alpha=.05). RESULTS: The 2-way analysis of variance revealed an interaction between product and surface coating (P=.0459). Given this interaction, the 12 combinations determined by surface treatment and material type were considered individually using the Tukey method. Vel-Mix, control (2.62 +/- 2.64 mg) had the most material loss and Vel-Mix, Clear Coat (0.48 +/- 0.29 mg) had the least material loss. Water sorption results indicated an interaction between the gypsum material and the surface treatment (P<.0001). The control groups of Microstone (299.2 +/- 49.6 mg) and Silky-Rock (159.0 +/- 8.5 mg) showed the most water sorption compared with the other treatment groups. CONCLUSIONS: This study demonstrated that a significant improvement in abrasion resistance occurred only with specific gypsum/surface hardener material combinations. Also, water sorption decreased significantly for Microstone and Silky-Rock gypsum materials when a surface hardener was used.

Does antenatal corticosteroid therapy affect birth weight and head circumference?

OBJECTIVE: To determine whether antenatal corticosteroid use is associated with weight and head circumference at birth. METHODS: We conducted a retrospective analysis of nonanomalous newborns admitted to 100 neonatal intensive care units from 23 to 34 6/7 weeks of gestation using multivariable analysis of variance that controlled for several potentially confounding variables. RESULTS: There were 14,338 cases of birth weight and 13,670 for head circumference available for analysis. Independent variables included maternal age, race, nulliparity, poor prenatal care, multiple gestation, obstetric complications, alcohol, smoking, illicit drugs, presentation, gestational age at birth, and method of delivery. The mean (+/-SD) birth weight was 1671 +/- 574 g and head circumference was 289 +/- 33 mm. The multivariable effect of antenatal corticosteroid on birth weight (mean +/- SE) was -63 +/- 5.7 g and on head circumference was -3.1 +/- 0.4 mm. Even after controlling for birth weight, a significant reduction in head circumference (-1.2 +/- 0.3 mm; 95% CI = -1.8, -0.6) was associated with antenatal corticosteroid use. This suggested that antenatal corticosteroids were associated with a greater reduction in brain growth than somatic growth. CONCLUSION: Antenatal corticosteroid may be associated with a reduction in birth weight and head circumference, independent of other major predictive factors. The reduction in head circumference persists even after controlling for the reduction in birth weight. The clinical significance of these findings is unknown.

Effect of antenatal and postnatal corticosteroid therapy on weight gain and head circumference growth in the nursery.

OBJECTIVE: To assess the effect of antenatal and postnatal corticosteroids on head circumference growth and weight gain from birth to discharge. METHODS: We conducted a retrospective analysis of nonanomalous newborns admitted to the neonatal intensive care unit from 23 to 34 6/7 weeks of gestation. Independent variables included maternal age, race, nulliparity, poor prenatal care, multiple gestation, obstetric complications, alcohol, tocolytic drugs, smoking, illicit drugs, gestational age at birth, presentation, method of delivery, 5-minute Apgar score < 7, surfactant use, severe intracranial hemorrhage, and length of stay. RESULTS: Antenatal and postnatal corticosteroids were given in 62% and 14% of the newborns, respectively, and 10% of newborns received both. The mean (+/-SD) weight gain and head circumference growth in the nursery was 440 +/- 582 g (n = 14,217) and 2.54 +/- 3.42 cm (n = 12,808), respectively. After multivariable analysis, use of antenatal corticosteroids did not affect weight gain (3.6 +/- 4.6 g) and head circumference growth (0.05 +/- 0.04 cm) compared with no exposure to perinatal corticosteroids, but postnatal corticosteroids were associated with significant reductions in weight gain and head circumference growth (-120 +/- 12.2 g and -0.53 +/- 0.11 cm, respectively). CONCLUSIONS: Antenatal corticosteroid therapy did not affect weight gain or head circumference growth in the nursery, even when used in conjunction with postnatal corticosteroid therapy.