Ecological structure of diversity-dependent diversification in Phanerozoic marine bivalves

Rigorous analysis of diversity-dependence-the hypothesis that the rate of proliferation of new species is inversely related to standing diversity-requires consideration of the ecology of the organisms in question. Differences between infaunal marine bivalves (living entirely within the sediment) and epifaunal forms (living partially or completely above the sediment-water interface) predict that these major ecological groups should have different diversity dynamics: epifaunal species may compete more intensely for space and be more susceptible to predation and physical disturbance. By comparing detrended standing diversity with rates of diversification, origination, and extinction in this exceptional fossil record, we find that epifaunal bivalves experienced significant, negative diversity-dependence in origination and net diversification, whereas infaunal forms show little appreciable relationship between diversity and evolutionary rates. This macroevolutionary contrast is robust to the time span over which dynamics are analysed, whether mass-extinction rebounds are included in the analysis, the treatment of stratigraphic ranges that are not maximally resolved, and the details of detrending. We also find that diversity-dependence persists over hundreds of millions of years, even though diversity itself rises nearly exponentially, belying the notion that diversity-dependence must imply equilibrial diversity dynamics.

Diversity-dependent diversification in the history of marine animals

AbstractBy comparing detrended estimates of diversity (taxonomic richness) and rates of origination, extinction, and net diversification, I show that at the global scale over the course of the Phanerozoic eon, rates of diversification and origination are negatively correlated with diversity. By contrast, extinction rates are only weakly correlated with diversity for the most part. These results hold for both genus- and species-level data and for many alternative analytical protocols. The asymmetry between extinction on the one hand and origination and net diversification on the other hand supports a model whereby extinction is largely driven by abiotic perturbations, with subsequent origination filling the void left by depleted diversity. Diversity dependence is somewhat weaker, but still evident, if the initial Ordovician radiation or rebounds from major mass extinctions are omitted from analysis; thus, diversity dependence is influenced, but not dominated, by these special intervals of Earth history. In the transition from Paleozoic to post-Paleozoic time, diversity dependence of origination weakens while that of extinction strengthens; however, diversity dependence of net diversification barely changes in strength. Despite nuances, individual clades largely yield results consistent with those for the aggregate data on all animals. On the whole, diversity-dependent diversification appears to be a pervasive factor in the macroevolution of marine animal life.

One-year implant survival following lateral window sinus augmentation using plasma rich in growth factors (PRGF): a retrospective study

Background

The aim of this study was to assess one-year implant survival after lateral window sinus augmentation using PRGF combined with various bone grafting materials.

Material and Methods

This was a retrospective chart review and radiographic analysis of patients that had undergone lateral window sinus augmentation with PRGF and had dental implants placed at least 6 months post augmentation. All implants included were followed up for at least one year after placement. Demographic, sinus and implant related characteristics (residual ridge height, sinus membrane perforation, type of graft material, implant length and width and ISQ at placement) were analyzed.

Results

A total of 31 patients with 39 sinus augmentations and 48 implants were included. The mean follow up was 22.8 ± 9.9 months. Implant survival was 95.8%, with 2 implants overall failing. Among all the variables assessed, the only one found to be associated with an increased risk for implant failure was the use of xenograft as bone grafting material in the sinus.

Conclusions

Within the limitations of this study, dental implants placed in maxillary sinuses grafted with PRGF in combination with bone grafting materials, exhibit high implant survival rates after at least one year follow up.

Key words:PRGF, sinus graft, growth factors, implant survival, platelet concentrates.

Identification of Racial Inequities in Access to Specialized Inpatient Heart Failure Care at an Academic Medical Center

BACKGROUND

Racial inequities for patients with heart failure (HF) have been widely documented. HF patients who receive cardiology care during a hospital admission have better outcomes. It is unknown whether there are differences in admission to a cardiology or general medicine service by race. This study examined the relationship between race and admission service, and its effect on 30-day readmission and mortality Methods: We performed a retrospective cohort study from September 2008 to November 2017 at a single large urban academic referral center of all patients self-referred to the emergency department and admitted to either the cardiology or general medicine service with a principal diagnosis of HF, who self-identified as white, black, or Latinx. We used multivariable generalized estimating equation models to assess the relationship between race and admission to the cardiology service. We used Cox regression to assess the association between race, admission service, and 30-day readmission and mortality.

RESULTS

Among 1967 unique patients (66.7% white, 23.6% black, and 9.7% Latinx), black and Latinx patients had lower rates of admission to the cardiology service than white patients (adjusted rate ratio, 0.91; 95% CI, 0.84-0.98, for black; adjusted rate ratio, 0.83; 95% CI, 0.72-0.97 for Latinx). Female sex and age >75 years were also independently associated with lower rates of admission to the cardiology service. Admission to the cardiology service was independently associated with decreased readmission within 30 days, independent of race.

CONCLUSIONS

Black and Latinx patients were less likely to be admitted to cardiology for HF care. This inequity may, in part, drive racial inequities in HF outcomes.

Development and prospective in-patient proof-of-concept validation of a surface photogrammetry + CT-based volumetric motion model for lung radiotherapy

PURPOSE

We develop and validate a motion model that uses real-time surface photogrammetry acquired concurrently with four-dimensional computed tomography (4DCT) to estimate respiration-induced changes within the entire irradiated volume, over arbitrarily many respiratory cycles.

METHODS

A research, couch-mounted, VisionRT (VRT) system was used to acquire optical surface data (15 Hz, ROI = 15 × 20 cm² ) from the thoraco-abdominal surface of a consented lung SBRT patient, concurrently with their standard-of-care 4DCT. The end-exhalation phase from the 4DCT was regarded as reference and for each remaining phase, deformation vector fields (DVFs) with respect to the reference phase were computed. To reduce dimensionality, the first two principal components (PCs) of the matrix of nine DVFs were calculated. In parallel, ten phase-averaged VRT surfaces were created. Surface DVFs and corresponding PCs were computed. A principal least squares regression was used to relate the PCs of surface DVF to those of volume DVFs, establishing a relationship between time-varying surface and the underlying time-varying volume. Proof-of-concept validation was performed during each treatment fraction by concurrently acquiring 30 s time series of real-time surface data and "ground truth" kV fluoroscopic data (FL). A ray-tracing algorithm was used to create a digitally reconstructed fluorograph (DRF), and motion trajectories of high-contrast, soft-tissue, anatomical features in the DRF were compared with those from kV FL.

RESULTS

For five of the six fluoroscopic acquisition sessions, the model out-performed 4DCT in predicting contour Dice coefficient with respect to fluoroscopy-derived contours. Similarly, the model exhibited a marked improvement over 4DCT for patch positions on the diaphragm. Model patch position errors varied from 5 to -15 mm while 4DCT errors ranged between 5 and -22.4 mm. For one fluoroscopic acquisition, a marked change in the a priori internal-external correlation resulted in model errors comparable to those of 4DCT.

CONCLUSIONS

We described the development and a proof-of-concept validation for a volumetric motion model that uses surface photogrammetry to correlate the time-varying thoraco-abdominal surface to the time-varying internal thoraco-abdominal volume. These early results indicate that the proposed approach can result in a marked improvement over 4DCT. While limited by the duration of the fluoroscopic acquisitions as well as the resolution of the acquired images, the DRF-based proof-of-concept technique developed here is model-agnostic, and therefore, has the potential to be used as an in-patient validation tool for other volumetric motion models.

Diversity-dependent evolutionary rates in early Palaeozoic zooplankton

The extent to which biological diversity affects rates of diversification is central to understanding macroevolutionary dynamics, yet no consensus has emerged on the importance of diversity-dependence of evolutionary rates. Here, we analyse the species-level fossil record of early Palaeozoic graptoloids, documented with high temporal resolution, to test directly whether rates of diversification were influenced by levels of standing diversity within this major clade of marine zooplankton. To circumvent the statistical regression-to-the-mean artefact, whereby higher- and lower-than-average values of diversity tend to be followed by negative and positive diversification rates, we construct a non-parametric, empirically scaled, diversity-independent null model by randomizing the observed diversification rates with respect to time. Comparing observed correlations between diversity and diversification rate to those expected from this diversity-independent model, we find evidence for negative diversity-dependence, accounting for up to 12% of the variance in diversification rate, with maximal correlation at a temporal lag of approximately 1 Myr. Diversity-dependence persists throughout the Ordovician and Silurian, despite a major increase in the strength and frequency of extinction and speciation pulses in the Silurian. By contrast to some previous work, we find that diversity-dependence affects rates of speciation and extinction nearly equally on average, although subtle differences emerge when we compare the Ordovician and Silurian.

Diagnostic potential of tumor DNA from ovarian cyst fluid

We determined whether the mutations found in ovarian cancers could be identified in the patients' ovarian cyst fluids. Tumor-specific mutations were detectable in the cyst fluids of 19 of 23 (83%) borderline tumors, 10 of 13 (77%) type I cancers, and 18 of 18 (100%) type II cancers. In contrast, no mutations were found in the cyst fluids of 18 patients with benign tumors or non-neoplastic cysts. Though large, prospective studies are needed to demonstrate the safety and clinical utility of this approach, our results suggest that the genetic evaluation of cyst fluids might be able to inform the management of the large number of women with these lesions.

DOI:http://dx.doi.org/10.7554/eLife.15175.001

More than a third of women develop ovarian cysts during their lifetimes. The vast majority of these cysts are harmless, but a small number are caused by ovarian cancers. These cancers often produce no symptoms until the disease has spread throughout the abdomen or to other organs, so many women go undiagnosed until their chances of being successfully treated are low. Currently, there is no reliable way to determine whether an ovarian cyst is cancerous without performing surgery. As a result, many women undergo unnecessary, invasive surgeries for harmless ovarian cysts.

Tumors shed cells and cell fragments into any fluid that surrounds them. Fluids from cysts in the pancreas, kidney, and thyroid are routinely examined to identify whether they contain cancerous cells. Now, Wang, Sundfeldt et al. show that ovarian cancers also shed DNA into the surrounding cyst fluid. Furthermore, mutations found in this DNA can provide valuable information about whether the cysts are cancerous.

The study was performed by extracting DNA from the fluid in ovarian cysts that had been surgically removed from 77 women. Of these cysts, 10 were harmless cysts, 12 were benign tumors, 31 were invasive cancers, and 24 were so-called borderline tumors, which fall somewhere between the benign tumors and invasive cancers. Only cysts associated with the borderline tumors and invasive cancers need to be surgically removed. Here, Wang, Sundfeldt et al. report that DNA mutations that are characteristic of ovarian cancers were found in 87% of the cysts associated with borderline tumors and invasive cancers. In contrast, these mutations were not found in any of the cysts that do not require surgery.

Fluid can be extracted from an ovarian cyst with a needle during an outpatient visit. Therefore, the results presented by Wang, Sundfeldt et al. suggest a relatively straightforward way of testing the DNA from ovarian cysts before deciding whether surgery is really necessary. First, however, larger studies that follow women with cysts over time will be necessary to confirm that this type of testing is effective and safe.

DOI:http://dx.doi.org/10.7554/eLife.15175.002

Improving DNA double-strand repair inhibitor KU55933 therapeutic index in cancer radiotherapy using nanoparticle drug delivery

Radiotherapy is a key component of cancer treatment. Because of its importance, there has been high interest in developing agents and strategies to further improve the therapeutic index of radiotherapy. DNA double-strand repair inhibitors (DSBRIs) are among the most promising agents to improve radiotherapy. However, their clinical translation has been limited by their potential toxicity to normal tissue. Recent advances in nanomedicine offer an opportunity to overcome this limitation. In this study, we aim to demonstrate the proof of principle by developing and evaluating nanoparticle (NP) formulations of KU55933, a DSBRI. We engineered a NP formulation of KU55933 using nanoprecipitation method with different lipid polymer nanoparticle formulation. NP KU55933 using PLGA formulation has the best loading efficacy as well as prolonged drug release profile. We demonstrated that NP KU55933 is a potent radiosensitizer in vitro using clonogenic assay and is more effective as a radiosensitizer than free KU55933 in vivo using mouse xenograft models of non-small cell lung cancer (NSCLC). Western blots and immunofluorescence showed NP KU55933 exhibited more prolonged inhibition of DNA repair pathway. In addition, NP KU55933 leads to lower skin toxicity than KU55933. Our study supports further investigations using NP to deliver DSBRIs to improve cancer radiotherapy treatment.

Abstract B39: Multitarget approach against PI3K, Aurora kinase, and BRD4 leads to improved antitumor activity in Myc-overexpressing lymphoma cells

Background: Myc has proven extremely difficult to target therapeutically. Therefore, we hypothesized that optimal inhibition of several key targetable pathways involved in Myc signaling could overcome this long-standing problem. We identified phosphoinositide 3-kinase (PI3K), aurora kinase (Aurk), and bromodomain protein (BRD)4 as the primary therapeutic targets to counteract Myc deregulation based on strong evidence that these pathways are essential for tumor maintenance in Myc-driven malignancies.

Methods: Cytotoxicity assays using MTS and trypan blue were used to compare levels of drug sensitivity in lymphoma cell lines with high and low Myc mRNA expression. Apoptosis and cell cycle assays were performed using Annexin V and Propidium Iodide staining. Murine xenograft models were used to assess the efficacy and tolerability of single vs. combined inhibition.

Results: Myc-overexpressing Burkitt lymphoma (Raji) cells were treated with various concentrations of small molecule inhibitors against PI3K (BEZ-235), Aurk (MLN-8237), or BRD4 (I-BET-151) for 48 to 72 hours and cell viability was evaluated. BEZ-235, MLN-8237, and I-BET-151 inhibited cell growth individually with IC-50 of 30 nM, 10 nM, and 650 nM, respectively. Dual treatment with BEZ-235/MLN-8237, BEZ-235/I-BET-151, or MLN-8237/I-BET-151 induced more significant cell growth inhibition as compared to treatment with the single agent alone. The combination index (CI) values were less than 1 at various drug concentrations, indicating that different combinations of BEZ-235, MLN-8237, and I-BET-151 were synergistic in terms of inhibitory effect on tumor cell viability. Superior activity of the dual inhibition was also noted in other Myc-overexpressing lymphoma cells, including Ramos and SUDHL4. Combination treatments also increased apoptosis and induced more pronounced cell cycle arrest compared to the single agent treatment alone. We then analyzed protein expression by Western blot in Myc-overexpressing cells treated with various combinations of BEZ-235, MLN-8237, and I-BET-151. Treatment with BEZ-235 in Myc-overexpressing lymphoma cells resulted in reduced phosphorylated levels of the downstream effector RPS6K, which promotes protein translation and proliferation. MLN-8237 reduced the expression of p-HisH3 and p-Aurk while increasing the expression of p-S6K. Treatment with I-BET-151 resulted in significant reduction of Myc expression. Combined treatments had minimal impact on protein expression patterns compared to individual treatments, and the synergistic effect was independent of depletion of cytoplasmic levels of Myc. Lastly, athymic nude mice bearing Ramos lymphoma xenografts were treated with BEZ-235, MLN-8237, I-BET-151, and various dual-combinations of each agent. The mean tumor volumes in mice treated with negative control, BEZ-235, I-BET-151, and MLN-8237 as single agents were 3480, 2364, 2320, and 671 mm3, respectively, at Day 28. Mice treated with BEZ-235/I-BET-151, MLN-8237/I-BET-151, and BEZ-235/MLN-8237 combinations had mean tumor volumes of 1709, 461, and 166 mm3, respectively, at Day 28. The survival rates for mice treated with negative control, BEZ-235, I-BET-151, and MLN-8237 as single agents were 0%, 10%, 10%, and 70%, respectively, at Day 35. The combination of BEZ-235 and MLN-8237 was associated with significant toxicity with 60% of mice dying from weight loss and failure to thrive despite tumor regression. Mice treated with the MLN-8237 and I-BET-151 combination demonstrated the best survival rate of 100% at Day 35.

Conclusion: Our data demonstrated that Myc-overexpressing tumors can be successfully targeted by inhibiting kinases associated with Myc-signaling. Specifically, MLN-8237, a small molecule inhibitor against AURK, induced apoptosis of Myc-overexpressing tumor cells in vitro and showed the most promising anti-tumor activity in mice bearing Myc-overexpressing lymphoma, especially when combined with I-BET-151, a BRD4 inhibitor.

Citation Format: Steven I. Park, Carolina P. Lin, Michael Foote, Trevor Parton, David B. Darr, Daniel Roth, Aadra P. Bhatt, Dirk P. Dittmer, Norman E. Sharpless, Blossom Damania. Multitarget approach against PI3K, Aurora kinase, and BRD4 leads to improved antitumor activity in Myc-overexpressing lymphoma cells. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr B39.

A systematic review of non-surgical treatments for lentigo maligna

Lentigo maligna (LM) is the most common melanocytic malignancy of the head and neck. If left untreated, LM can progress to lentigo maligna melanoma (LMM). Complete surgical excision is the gold standard for treatment, however, due to the location, size, and advanced age of patients, surgery is not always acceptable. As a result, there is ongoing interest in alternative, less invasive treatment modalities. The objective was to provide a structured review of key literature reporting the use of radiotherapy, imiquimod and laser therapy for the management of LM in patients where surgical resection is prohibited. An independent review was conducted following a comprehensive search of the National Library of Medicine using MEDLINE and PubMed, Embase, Scopus, ScienceDirect and Cochrane Library databases. Data were presented in tabular format, and crude data pooled to calculate mean recurrence rates for each therapy. 29 studies met the inclusion criteria: radiotherapy 10; topical imiquimod 10; laser therapies 9. Radiotherapy demostrated recurrence rates of up to 31% (mean 11.5%), with follow-up durations of 1-96 months. Topical imiquimod recurrence rates were up to 50% (mean 24.5%), with follow-up durations of 2-49 months. Laser therapy yielded recurrence rates of up to 100% (mean 34.4%), and follow-up durations of 8-78 months. in each of the treatment series the I(2) value measuring statistical heterogeneity exceeded the accepted threshold of 50% and as such a meta-analysis of included data were inappropriate. For non-surgical patients with LM, radiotherapy and topical imiquimod were efficacious treatments. Radiotherapy produced superior complete response rates and fewer recurrences than imiquimod although both are promising non-invasive modalities. There was no consistent body of evidence regarding laser therapy although response rates of up to 100% were reported in low quality studies. A prospective comparative trial is indicated and would provide accurate data on the long-term efficacy and overall utility of these treatments.

Kidney paired donation: a payer perspective

Kidney transplantation is the most cost-effective and clinically effective form of renal replacement therapy. Due to long wait times for deceased donors, kidney transplantation is not available to many patients with incompatible living donors. Increased access to kidney transplantation is a shared goal that can be achieved through kidney paired donation (KPD). A single, national system of KPD administered to a set of clinical and ethical standards determined by a consensus of stakeholders including recipients, donors, providers, payers and the United States federal government will provide the best opportunity to offer kidney transplantation to the most people and particularly to those currently unlikely to receive a transplant. We propose that this system will use uniform tissue typing algorithms and a computerized donor and recipient matching program using a national pool of willing donors. The proposed system can be managed best through a single administrative structure that takes advantage of uniform donor evaluation and management with a standardized organ acquisition charge that recognizes that the current lack of standardization contributes to delays in transplantation and payment to programs. This program will use the existing Organ Procurement Organization infrastructure to manage the logistics of organ acquisition, transportation and billing.

Evolutionary dynamics of taxonomic structure

The distribution of species among genera and higher taxa has largely untapped potential to reveal among-clade variation in rates of origination and extinction. The probability distribution of the number of species within a genus is modelled with a stochastic, time-homogeneous birth-death model having two parameters: the rate of species extinction, μ, and the rate of genus origination, γ, each scaled as a multiple of the rate of within-genus speciation, λ. The distribution is more sensitive to γ than to μ, although μ affects the size of the largest genera. The species : genus ratio depends strongly on both γ and μ, and so is not a good diagnostic of evolutionary dynamics. The proportion of monotypic genera, however, depends mainly on γ, and so may provide an index of the genus origination rate. Application to living marine molluscs of New Zealand shows that bivalves have a higher relative rate of genus origination than gastropods. This is supported by the analysis of palaeontological data. This concordance suggests that analysis of living taxonomic distributions may allow inference of macroevolutionary dynamics even without a fossil record.

Modulation of voltage-gated ion channels in rat retinal ganglion cells mediated by somatostatin receptor subtype 4

Somatostatin (somatotropin release-inhibiting factor [SRIF]) is known to modulate the excitability of retinal ganglion cells, but the membrane mechanisms responsible and the extent to which intracellular calcium signaling is affected have not been determined. We show that somatostatin receptor subtype 4 (sst(4)) is expressed specifically in rat ganglion cells and that the generation of repetitive action potentials by isolated ganglion cells is reduced in the presence of L-803,087, a selective sst(4) agonist (10 nM). Under voltage clamp, L-803,087 increased outward K(+) currents by 51.1 ± 13.1% at 0 mV and suppressed Ca(2+) channel currents by 32.5 ± 9.4% at -10 mV in whole cell patch-clamped ganglion cells. The N-type Ca(2+) channel blocker ω-conotoxin GVIA (CTX, 1 μM) reduced L-type Ca(2+) current (I(Ca)) in ganglion cells by 43.5 ± 7.2% at -10 mV, after which addition of L-803,087 further reduced I(Ca) by 28.0 ± 16.0% . In contrast, ganglion cells treated first with nifedipine (NIF, 10 μM), which blocked 46.1 ± 3.5% of the control current at -10 mV, did not undergo any further reduction in I(Ca) in the presence of L-803,087 (-3.5 ± 3.8% vs. NIF), showing that stimulation of sst(4) reduces Ca(2+) influx through L-type Ca(2+) channels. To assess the effects of sst(4) stimulation on intracellular Ca(2+) levels ([Ca(2+)](i)) in ganglion cells, fura-2 was used to measure changes in [Ca(2+)](i) in response to depolarization induced by elevated [K(+)](o). [Ca(2+)](i) was increased to a lesser extent (86%) in the presence of L-803,087 compared with recordings made in the absence of the sst(4) agonist and this effect was blocked by NIF (10 μM). Suppression of spiking and Ca(2+) signaling via sst(4) may contribute to the reported neuroprotective actions of somatostatin and promote ganglion cell survival following ischemia and axonal trauma.

Clinical outcomes of adult patients with primary intracranial germinomas treated with low-dose craniospinal radiotherapy and local boost

The authors document the long term follow up of adult patients with histologically proven primary intracranial germinoma treated with radiotherapy alone using a craniospinal with local boost technique. A retrospective review was conducted on adults diagnosed with intracranial germinoma who received radiotherapy at the Princess Margaret Hospital, Toronto from 1990 to 2007. The study group consisted of 10 males with a median age of 24.1 years. All patients received radiotherapy alone using craniospinal radiotherapy and local boost. There were 10 patients (all male) with a median follow up of 10.9 years (range 2.2-18.9 years). At date of last follow up all patients were still alive, none with relapsed disease. Seven of ten patients (70%) had panhypopituitarianism prior to commencing radiotherapy and hormonal function was not affected in those with an intact pituitary axis. There was no reported cognitive decline in the treated cohort. For adult intracranial germinomas, with long term follow up, low-dose craniospinal radiotherapy with in field boost is highly effective with minimal morbidity.

Reefs as Cradles of Evolution and Sources of Biodiversity in the Phanerozoic

Large-scale biodiversity gradients among environments and habitats are usually attributed to a complex array of ecological and evolutionary factors. We tested the evolutionary component of such gradients by compiling the environments of the geologically oldest occurrences of marine genera and using sampling standardization to assess if originations tended to be clustered in particular environments. Shallow, tropical environments and carbonate substrates all tend to have harbored high origination rates. Diversity within these environments tended to be preferentially generated in reefs, probably because of their habitat complexity. Reefs were also prolific at exporting diversity to other environments, which might be a consequence of low-diversity habitats being more susceptible to invasions.

Vacuum and forceps training in residency: experience and self-reported competency

OBJECTIVE

Determine chief residents' experience with vacuum and forceps deliveries and self-perceived competencies with the procedures.

STUDY DESIGN

Study 1: A written questionnaire was mailed to all fourth year residents in US RRC approved Ob/Gyn programs. Study 2: The study was replicated using a web-based survey the following year. Data were analyzed with chi (2) and Wilcoxon Signed Rank tests using SPSS.

RESULTS

Surveys were received from 238 residents (20%) in Study 1 and 269 residents in Study 2 (23%, representing 50% of all residency programs). In both studies, residents reported performing significantly less forceps than vacuum deliveries. Virtually all residents wanted to learn to perform both deliveries, indicated attendings were willing to teach both, and felt competent to perform vacuum deliveries (Study 1, 94.5%; Study 2, 98.5%); only half felt competent to perform forceps deliveries (Study 1, 57.6%; Study 2, 55.0%). The majority of residents who felt competent to perform forceps deliveries reported that they would predominately use forceps or both methods of deliveries in their practice (Study 1, 75.8%; Study 2, 64.6%). The majority of residents who reported that they did not feel competent to perform forceps deliveries reported that they would predominately use vacuum deliveries in their practice (Study 1, 86.1%; Study 2, 84.2%).

CONCLUSION

Current training results in a substantial portion of residents graduating who do not feel competent to perform forceps deliveries. Perceived competency affected future operative delivery plans.

Increased Longevities of Post-Paleozoic Marine Genera After Mass Extinctions

Cohorts of marine taxa that originated during recoveries from mass extinctions were commonly more widespread spatially than those originating at other times. Coupled with the recognition of a correlation between the geographic ranges and temporal longevities of marine taxa, this observation predicts that recovery taxa were unusually long-lived geologically. We analyzed this possibility by assessing the longevities of marine genus cohorts that originated in successive substages throughout the Phanerozoic. Results confirm that several mass extinction recovery cohorts were significantly longer lived than other cohorts, but this effect was limited to the post-Paleozoic, suggesting differences in the dynamics of Paleozoic versus post-Paleozoic diversification.

Determinants of extinction in the fossil record

The causes of mass extinctions and the nature of biological selectivity at extinction events are central questions in palaeobiology. It has long been recognized, however, that the amount of sedimentary rock available for sampling may bias perceptions of biodiversity and estimates of taxonomic rates of evolution. This problem has been particularly noted with respect to the principal mass extinctions. Here we use a new compilation of the amount of exposed marine sedimentary rock to predict how the observed fossil record of extinction would appear if the time series of true extinction rates were in fact smooth. Many features of the highly variable record of apparent extinction rates within marine animals can be predicted on the basis of temporal variation in the amount of exposed rock. Although this result is consistent with the possibility that a common geological cause determines both true extinction rates and the amount of exposed rock, it also supports the hypothesis that much of the observed short-term volatility in extinction rates is an artefact of variability in the stratigraphic record.

Effects of sampling standardization on estimates of Phanerozoic marine diversification

Global diversity curves reflect more than just the number of taxa that have existed through time: they also mirror variation in the nature of the fossil record and the way the record is reported. These sampling effects are best quantified by assembling and analyzing large numbers of locality-specific biotic inventories. Here, we introduce a new database of this kind for the Phanerozoic fossil record of marine invertebrates. We apply four substantially distinct analytical methods that estimate taxonomic diversity by quantifying and correcting for variation through time in the number and nature of inventories. Variation introduced by the use of two dramatically different counting protocols also is explored. We present sampling-standardized diversity estimates for two long intervals that sum to 300 Myr (Middle Ordovician-Carboniferous; Late Jurassic-Paleogene). Our new curves differ considerably from traditional, synoptic curves. For example, some of them imply unexpectedly low late Cretaceous and early Tertiary diversity levels. However, such factors as the current emphasis in the database on North America and Europe still obscure our view of the global history of marine biodiversity. These limitations will be addressed as the database and methods are refined.

Clinical research strategies in biotechnology

Clinical drug development involves many steps and is extremely costly to the sponsoring company. There is intense pressure on sponsors to be faster, more efficient, and less costly. Sponsors also need to be globally oriented in their drug-development processes. There are several ways in which clinical drug development may be done more quickly and at less cost. These strategies include the use of large contract research organizations (CRO) and site management organizations (SMO). Although there is an estimated 2000 CRO worldwide, the use of SMO is quite limited but growing rapidly. Changes in the US Food and Drug Administration (FDA), especially harmonization between its two divisions Center for Biologics Evaluation and Research (CBER) and Center for Drug Evaluation and Research (CDER), and the use of CRO and SMO will make for interesting and challenging times for sponsors.

Hematopoietic growth factors in cancer chemotherapy

Hematopoietic growth factors have made a significant impact on the treatment of cancer, primarily in the prevention of infections associated with chemotherapy-induced neutropenia, in progenitor cell transplantation, in chemotherapy-induced thrombocytopenia, and in chemotherapy-induced anemia. As seen with this review, our basic understanding of hematopoietic growth factors and their clinical potential continue to expand. Work will need to continue, especially with the new thrombopoietic factors, megakaryocyte growth and developing factor, thrombopoietin, and IL-11, to fully categorize their biology and clinical characteristics.

Megakaryocyte growth and development factor (MGDF): an Mpl ligand and cytokine that regulates thrombopoiesis

Megakaryocyte growth and development factor (MGDF) is a ligand for the Mpl receptor related to thrombopoietin (TPO). MGDF stimulates megakaryocytopoiesis and thrombopoiesis, and is highly selective to cells bearing the Mpl receptor. Studies done in rodents, nonhuman primates, and humans have confirmed that MGDF can increase platelet counts in normal and chemotherapy- or radiotherapy-treated subjects. Platelet function and physiology remain normal after MGDF administration, with no effect on platelet aggregation. Pegylated recombinant human MGDF (PEG-rHuMGDF) was used clinically with initial success. Cancer patients receiving chemotherapy showed dose-dependent increases in platelet counts and increases in bone marrow megakaryocytes. Clinical development of PEG-rHuMGDF was halted owing to the formation of neutralizing antibodies in some patients and normal volunteers who received the drug. The application of exogenous recombinant Mpl ligands should be explored in the setting of randomized clinical trials and the findings extended to mobilization of CD34+ stem cells, ex vivo expansion techniques, and use in platelet abnormalities.

Biopharmaceutical drug development: Filgrastim (r-metHuG-CSF) use in patients with HIV infection

Hematopoietic growth factors are well known to increase neutrophil counts and support the administration of myelotoxic and myelosuppressive therapies, especially chemotherapies. Filgrastim (r-metHuG-CSF) has been used in the setting of HIV disease to treat neutropenia and HIV-associated neutrophil defects. This article reviews the biology, product characteristics, and preclinical and clinical development of Filgrastim. Emphasis is given on the use of Filgrastim in the setting of HIV infection and AIDS.

The use of Filgrastim in AIDS-related neutropenia

Neutropenic individuals are at high risk for bacterial and fungal infections. Filgrastim (r-metHuG-CSF, NEUPOGEN) has been shown to improve chemotherapy-induced neutropenia significantly. Because a high incidence of HIV-infected patients have neutropenia, often associated with myelosuppressive antiretroviral medication, Filgrastim is frequently used as a treatment strategy for this HIV-associated neutropenia. This review summarizes published work related to the use of Filgrastim in HIV-infected patients. Literature bases (EMBASE, MEDLINE, Int. Pharm. Abs., SciSearch, and Aidsline) from 1970 to 1998 were searched for articles describing the relationship of Filgrastim and ANC to bacterial infection rates, bacterial infection outcome, and overall survival. Thirty-five related articles were identified during this search. Filgrastim appears to have a significant role in increasing peripheral ANC and enhancing neutrophil function in patients with HIV infection and AIDS. This may translate into a clinical benefit of delivery of full-dose myelosuppressive antiretroviral therapy and decreased susceptibility to infections and increased survival in this patient population.

Absolute measures of the completeness of the fossil record

Measuring the completeness of the fossil record is essential to understanding evolution over long timescales, particularly when comparing evolutionary patterns among biological groups with different preservational properties. Completeness measures have been presented for various groups based on gaps in the stratigraphic ranges of fossil taxa and on hypothetical lineages implied by estimated evolutionary trees. Here we present and compare quantitative, widely applicable absolute measures of completeness at two taxonomic levels for a broader sample of higher taxa of marine animals than has previously been available. We provide an estimate of the probability of genus preservation per stratigraphic interval, and determine the proportion of living families with some fossil record. The two completeness measures use very different data and calculations. The probability of genus preservation depends almost entirely on the Palaeozoic and Mesozoic records, whereas the proportion of living families with a fossil record is influenced largely by Cenozoic data. These measurements are nonetheless highly correlated, with outliers quite explicable, and we find that completeness is rather high for many animal groups.

Evolutionary and preservational constraints on origins of biologic groups: divergence times of eutherian mammals

Some molecular clock estimates of divergence times of taxonomic groups undergoing evolutionary radiation are much older than the groups' first observed fossil record. Mathematical models of branching evolution are used to estimate the maximal rate of fossil preservation consistent with a postulated missing history, given the sum of species durations implied by early origins under a range of species origination and extinction rates. The plausibility of postulated divergence times depends on origination, extinction, and preservation rates estimated from the fossil record. For eutherian mammals, this approach suggests that it is unlikely that many modern orders arose much earlier than their oldest fossil records.

Filgrastim restores interleukin-2 production in blood from patients with advanced human immunodeficiency virus infection

Filgrastim induces lymphocytosis, including all T cell subsets, and increased ex vivo interleukin (IL)-2 release as well as lymphocyte proliferation. Since Filgrastim is increasingly used in patients with human immunodeficiency virus (HIV) infection, the effect of Filgrastim on ex vivo cytokine production was determined. Whole blood from 8 healthy volunteers, 5 high-risk volunteers, and 31 HIV-infected outpatients was assayed for cytokine production in response to endotoxin (LPS) or staphylococcal enterotoxin B (SEB) in the presence or absence of 100 ng/mL Filgrastim. LPS-inducible blood cytokine release of HIV-infected patients was not different from that of normal or high-risk volunteers. The suppressive effect of Filgrastim on LPS-inducible blood tumor necrosis factor-alpha and interferon-gamma formation in normal volunteers was not found in HIV-infected patients. Patients with advanced HIV infection showed reduced IL-2 and IL-4 release in the presence of SEB. In the presence of Filgrastim, IL-2 production was partially restored.

Managing diabetes through home care

Diabetes management will hold an increasingly larger place in home care services as the population ages. Advocate Home Health Services in Oakbrook, Illinois, has developed a diabetes management program to help people with diabetes live more easily with this chronic disease.

Clinical benefits of improving host defences with rHuG-CSF

Recombinant human granulocyte colony-stimulating factor (rHuG-CSF) has been shown to stimulate the production and function of neutrophils in vitro and in vivo. Clinical studies in patients receiving myelosuppressive chemotherapy showed earlier neutrophil recovery, a reduction in infectious complications of neutropenia, and the use of fewer antibiotics. Its use has also been established for mitigating the infectious complications associated with severe chronic neutropenia (SCN). Data are emerging that neutropenia also contributes to the risk of infections in patients with acquired immunodeficiency syndrome (AIDS) and in neonates with presumed sepsis, and that rHuG-CSF may be a useful adjunct therapy in these patients. More recent studies have focused on enhancing neutrophil number and function in patients with infections not associated with neutropenia. These studies were approached cautiously because of the suggestion that neutrophils might non-selectively amplify the body's inflammatory response in the immunocompetent host and lead to inadvertent tissue injury. Preclinical models have provided a strong rationale for clinical studies to determine whether rHuG-CSF lessens the severity or duration of serious infections or their complications in patients with suboptimal outcome from antibiotics. These studies suggest that elevation of neutrophil levels in these settings is not only safe but has clinical benefit.

Ecological Controls on the Evolutionary Recovery of Post-Paleozoic Crinoids

Analysis of morphological characters of a global sample of post-Paleozoic crinoid echinoderms shows that this group underwent a rapid diversification after the extinction at the end of the Permian to reach maximal morphological disparity by the Late Triassic, which is essentially the same evolutionary pattern seen during the group's early Paleozoic radiation. The accelerated morphological diversification of a single class implies that, even if clades surviving from the Paleozoic represented ecological incumbents that hindered the origin of new higher taxa, species within individual higher taxa rapidly exploited available ecological opportunities in the Mesozoic.