Regulation of the Ca2+ Channel CaV1.2 Supports Spatial Memory and Its Flexibility and LTD

Widespread release of norepinephrine (NE) throughout the forebrain fosters learning and memory via adrenergic receptor (AR) signaling, but the molecular mechanisms are largely unknown. The β2 AR and its downstream effectors, the trimeric stimulatory Gs-protein, adenylyl cyclase (AC), and the cAMP-dependent protein kinase A (PKA), form a unique signaling complex with the L-type Ca2+ channel (LTCC) CaV1.2. Phosphorylation of CaV1.2 by PKA on Ser1928 is required for the upregulation of Ca2+ influx on β2 AR stimulation and long-term potentiation induced by prolonged theta-tetanus (PTT-LTP) but not LTP induced by two 1-s-long 100-Hz tetani. However, the function of Ser1928 phosphorylation in vivo is unknown. Here, we show that S1928A knock-in (KI) mice of both sexes, which lack PTT-LTP, express deficiencies during initial consolidation of spatial memory. Especially striking is the effect of this mutation on cognitive flexibility as tested by reversal learning. Mechanistically, long-term depression (LTD) has been implicated in reversal learning. It is abrogated in male and female S1928A knock-in mice and by β2 AR antagonists and peptides that displace β2 AR from CaV1.2. This work identifies CaV1.2 as a critical molecular locus that regulates synaptic plasticity, spatial memory and its reversal, and LTD.SIGNIFICANCE STATEMENT We show that phosphorylation of the Ca2+ channel CaV1.2 on Ser1928 is important for consolidation of spatial memory and especially its reversal, and long-term depression (LTD). Identification of Ser1928 as critical for LTD and reversal learning supports the model that LTD underlies flexibility of reference memory.

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.

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.

Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) Motor Dysfunction Modeled in Mice

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some carriers of the fragile X premutation (PM). In PM carriers, there is a moderate expansion of a CGG trinucleotide sequence (55-200 repeats) in the fragile X gene (FMR1) leading to increased FMR1 mRNA and small to moderate decreases in the fragile X mental retardation protein (FMRP) expression. The key symptoms of FXTAS include cerebellar gait ataxia, kinetic tremor, sensorimotor deficits, neuropsychiatric changes, and dementia. While the specific trigger(s) that causes PM carriers to progress to FXTAS pathogenesis remains elusive, the use of animal models has shed light on the underlying neurobiology of the altered pathways involved in disease development. In this review, we examine the current use of mouse models to study PM and FXTAS, focusing on recent advances in the field. Specifically, we will discuss the construct, face, and predictive validities of these PM mouse models, the insights into the underlying disease mechanisms, and potential treatments.

Inhibition of 14-3-3 Proteins Leads to Schizophrenia-Related Behavioral Phenotypes and Synaptic Defects in Mice

BACKGROUND

The 14-3-3 family of proteins is implicated in the regulation of several key neuronal processes. Previous human and animal studies suggested an association between 14-3-3 dysregulation and schizophrenia.

METHODS

We characterized behavioral and functional changes in transgenic mice that express an isoform-independent 14-3-3 inhibitor peptide in the brain.

RESULTS

We recently showed that 14-3-3 functional knockout mice (FKO) exhibit impairments in associative learning and memory. We report here that these 14-3-3 FKO mice display other behavioral deficits that correspond to the core symptoms of schizophrenia. These behavioral deficits may be attributed to alterations in multiple neurotransmission systems in the 14-3-3 FKO mice. In particular, inhibition of 14-3-3 proteins results in a reduction of dendritic complexity and spine density in forebrain excitatory neurons, which may underlie the altered synaptic connectivity in the prefrontal cortical synapse of the 14-3-3 FKO mice. At the molecular level, this dendritic spine defect may stem from dysregulated actin dynamics secondary to a disruption of the 14-3-3-dependent regulation of phosphorylated cofilin.

CONCLUSIONS

Collectively, our data provide a link between 14-3-3 dysfunction, synaptic alterations, and schizophrenia-associated behavioral deficits.

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.

14-3-3 protein targets misfolded chaperone-associated proteins to aggresomes

The aggresome is a key cytoplasmic organelle for sequestration and clearance of toxic protein aggregates. Although loading misfolded proteins cargos to dynein motors has been recognized as an important step in the aggresome formation process, the molecular machinery that mediates the association of cargos with the dynein motor is poorly understood. Here, we report a new aggresome-targeting pathway that involves isoforms of 14-3-3, a family of conserved regulatory proteins. 14-3-3 interacts with both the dynein-intermediate chain (DIC) and an Hsp70 co-chaperone Bcl-2-associated athanogene 3 (BAG3), thereby recruiting chaperone-associated protein cargos to dynein motors for their transport to aggresomes. This molecular cascade entails functional dimerization of 14-3-3, which we show to be crucial for the formation of aggresomes in both yeast and mammalian cells. These results suggest that 14-3-3 functions as a molecular adaptor to promote aggresomal targeting of misfolded protein aggregates and may link such complexes to inclusion bodies observed in various neurodegenerative diseases.

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.

14-3-3 proteins in neurological disorders

14-3-3 proteins were originally discovered as a family of proteins that are highly expressed in the brain. Through interactions with a multitude of binding partners, 14-3-3 proteins impact many aspects of brain function including neural signaling, neuronal development and neuroprotection. Although much remains to be learned and understood, 14-3-3 proteins have been implicated in a variety of neurological disorders based on evidence from both clinical and laboratory studies. Here we will review previous and more recent research that has helped us understand the roles of 14-3-3 proteins in both neurodegenerative and neuropsychiatric diseases.

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.

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.

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.

Biology and clinical potential of stem-cell factor

Stem-cell factor (SCF) is a hematopoietic growth factor that acts on both primitive and mature progenitor cells. Preclinical studies have shown that recombinant SCF can protect against lethal irradiation, elicit multilineage hematopoietic responses and increases in bone marrow cellularity, and increase the number of circulating peripheral blood progenitor cells (PBPCs) in a dose-dependent manner. Both preclinical and early clinical studies using recombinant methionyl human SCF plus recombinant methionyl human granulocyte colony-stimulating factor (Filgrastim) have demonstrated increased PBPC mobilization as compared with the use of either factor alone. These data suggest a clinical role for the combination.

Calibrating the Ordovician Radiation of marine life: implications for Phanerozoic diversity trends

It has long been suspected that trends in global marine biodiversity calibrated for the Phanerozoic may be affected by sampling problems. However, this possibility has not been evaluated definitively, and raw diversity trends are generally accepted at face value in macroevolutionary investigations. Here, we analyze a global-scale sample of fossil occurrences that allows us to determine directly the effects of sample size on the calibration of what is generally thought to be among the most significant global biodiversity increases in the history of life: the Ordovician Radiation. Utilizing a composite database that includes trilobites, brachiopods, and three classes of molluscs, we conduct rarefaction analyses to demonstrate that the diversification trajectory for the Radiation was considerably different than suggested by raw diversity time-series. Our analyses suggest that a substantial portion of the increase recognized in raw diversity depictions for the last three Ordovician epochs (the Llandeilian, Caradocian, and Ashgillian) is a consequence of increased sample size of the preserved and catalogued fossil record. We also use biometric data for a global sample of Ordovician trilobites, along with methods of measuring morphological diversity that are not biased by sample size, to show that morphological diversification in this major clade had leveled off by the Llanvirnian. The discordance between raw diversity depictions and more robust taxonomic and morphological diversity metrics suggests that sampling effects may strongly influence our perception of biodiversity trends throughout the Phanerozoic.

Fossil preservation and the stratigraphic ranges of taxa

The incompleteness of the fossil record hinders the inference of evolutionary rates and patterns. Here, we derive relationships among true taxonomic durations, preservation probability, and observed taxonomic ranges. We use these relationships to estimate original distributions of taxonomic durations, preservation probability, and completeness (proportion of taxa preserved), given only the observed ranges. No data on occurrences within the ranges of taxa are required. When preservation is random and the original distribution of durations is exponential, the inference of durations, preservability, and completeness is exact. However, reasonable approximations are possible given non-exponential duration distributions and temporal and taxonomic variation in preservability. Thus, the approaches we describe have great potential in studies of taphonomy, evolutionary rates and patterns, and genealogy. Analyses of Upper Cambrian-Lower Ordovician trilobite species, Paleozoic crinoid genera, Jurassic bivalve species, and Cenozoic mammal species yield the following results: (1) The preservation probability inferred from stratigraphic ranges alone agrees with that inferred from the analysis of stratigraphic gaps when data on the latter are available. (2) Whereas median durations based on simple tabulations of observed ranges are biased by stratigraphic resolution, our estimates of median duration, extinction rate, and completeness are not biased.(3) The shorter geologic ranges of mammalian species relative to those of bivalves cannot be attributed to a difference in preservation potential. However, we cannot rule out the contribution of taxonomic practice to this difference. (4) In the groups studied, completeness (proportion of species [trilobites, bivalves, mammals] or genera [crinoids] preserved) ranges from 60% to 90%. The higher estimates of completeness at smaller geographic scales support previous suggestions that the incompleteness of the fossil record reflects loss of fossiliferous rock more than failure of species to enter the fossil record in the first place.

The new generation of recombinant human hematopoietic cytokines

In the past year, the most exciting development in the field of hematopoietic growth factors has been the identification of the platelet-inducing factor Mpl ligand. Administration of recombinant Mpl ligand may alleviate the potential for hemorrhagic complications following cancer therapies. Stem cell factor continues to be studied clinically in the mobilization of peripheral blood cells for transplantation.

The clinical utility of granulocyte colony-stimulating factor: early achievements and future promise

Recombinant granulocyte colony-stimulating factor (rHuG-CSF) is a hematopoietic growth factor that acts selectively on the neutrophil lineage, and has had a major impact on clinical practice. Two forms are in clinical use: filgrastim has been approved for use in more than 45 countries for the amelioration of chemotherapy-induced neutropenia and restoration of granulopoiesis following bone-marrow transplantation and lenograstim has been approved in Europe and Japan. In some countries, rHuG-CSF is also approved for various other indications, such as severe chronic neutropenia. Infection and neutropenia are a major cause of morbidity and mortality following cytotoxic chemotherapy, and there is a known correlation between neutropenia and the risk of infection. Hematopoietic growth factors have been used successfully in the prevention and treatment of neutropenia. There is evidence to suggest that use of rHuG-CSF before the onset of neutropenia allows patients to receive the maximum benefit; however, patients who do not receive rHuG-CSF prophylactically still benefit from the use of rHuG-CSF for the treatment of febrile neutropenia. These patients have an accelerated neutrophil recovery and a shorter duration of febrile neutropenia. These effects seem to translate into a significant reduction in the number of patients requiring prolonged hospitalization. This paper reviews the use of rHuG-CSF in the treatment of febrile neutropenia and describes how it is routinely used by hematologists and oncologists in non-clinical trial settings.

Stem cell factor is a potent synergistic factor in hematopoiesis

Stem cell factor (SCF), a ligand for c-kit, has a broad range of activities including effects on cells at or near the level of the multipotential stem cell as well as on committed cells. Preclinical studies show that SCF can protect against lethal irradiation, elicit multilineage responses in peripheral blood and bone marrow cellularity, and increase circulating peripheral blood progenitor cells (PBPC) in a dose-dependent manner. Recombinant human SCF has major clinical potential through its synergy with other factors, especially recombinant human granulocyte colony-stimulating factor, to enhance mobilization of PBPC.

Paleozoic record of morphologica diversity in blastozoan echinoderms

There has been extensive debate about the magnitude and implications of morphological diversity in early Paleozoic animals, with some workers using apparently rapid initial diversification to infer unusual evolutionary processes. Analysis of discrete morphological characters shows that initial morphological diversification in the echinoderm subphylum Blastozoa was so pronounced that morphological diversity relative to taxonomic diversity was greatest in the Cambrian, whereas morphological diversity itself was greatest in the Middle and Upper Ordovician. Thus, a small number of Cambrian taxa sparsely occupied a large range in morphological space, whereas subsequent diversification involved expansion and filling of morphospace. A measure of clade-shape asymmetry and a method for statistical testing of clade shape are used to show that morphological diversity is significantly concentrated early in the history of the Blastozoa. The subphylum represents the highest biologic level at which temporal patterns of morphological diversity have been analyzed. Because this study is based on explicit morphological analysis, not taxonomic proxies for morphological diversity, the results are not artifacts of taxonomic practice.