Cytosolic concentrations of actin binding proteins and the implications for in vivo F-actin turnover

Understanding how numerous actin-binding proteins (ABPs) work in concert to control the assembly, organization, and turnover of the actin cytoskeleton requires quantitative information about the levels of each component. Here, we measured the cellular concentrations of actin and the majority of the conserved ABPs in Saccharomyces cerevisiae, as well as the free (cytosolic) fractions of each ABP. The cellular concentration of actin is estimated to be 13.2 µM, with approximately two-thirds in the F-actin form and one-third in the G-actin form. Cellular concentrations of ABPs range from 12.4 to 0.85 µM (Tpm1> Pfy1> Cof1> Abp1> Srv2> Abp140> Tpm2> Aip1> Cap1/2> Crn1> Sac6> Twf1> Arp2/3> Scp1). The cytosolic fractions of all ABPs are unexpectedly high (0.6-0.9) and remain so throughout the cell cycle. Based on these numbers, we speculate that F-actin binding sites are limited in vivo, which leads to high cytosolic levels of ABPs, and in turn helps drive the rapid assembly and turnover of cellular F-actin structures.

Staphylococcus aureus bacteriuria: implications and management

Background

Staphylococcus aureus is isolated in around 0.2%-4% of positive urinary cultures, more commonly in the contexts of long-term care, urological abnormalities and procedures, male sex, older age and comorbidities. Isolation may represent contamination, colonization, urinary tract infection or bacteraemic seeding from another site, and may be linked to S. aureus bacteraemia. However, there is little guidance on investigation and management of S. aureus bacteriuria. We performed a retrospective analysis of cases in our service, including clinical characteristics, investigations and treatment.

Methods

Data were collected on all urine samples taken from adult patients over a 5-year period from which S. aureus was isolated. Detailed analysis including investigations and management was conducted in those collected over a 1-year period.

Results

From 511 patients, 668 urine cultures positive for S. aureus were identified; 6.5% of cases were positive for MRSA. Of 93 patients who had blood cultures taken, there were 6 cases of S. aureus bacteraemia, 4 of which were associated with urological instrumentation. Of 94 cases analysed in detail, 57% were treated with antibiotics, and 49% had repeat urine cultures. Factors associated with recurrence were urinary catheterization, urological abnormality, diabetes and inpatient status.

Conclusions

Our experience does not support the routine taking of blood cultures or treatment of asymptomatic bacteriuria in well patients with S. aureus bacteriuria in this setting. However, repeat urine culture, and investigation and treatment of higher risk patients, for example, prior to bladder instrumentation, may be warranted. We propose a simple algorithm to guide clinicians.

The Genomics Education Partnership: First findings on genomics research in community colleges

The Genomics Education Partnership (GEP), a consortium of diverse colleges/universities, provides support for integrating genomics research into undergraduate curricula. To increase research opportunities for underrepresented students, GEP is expanding to more community colleges (CC). Genomics research, requiring only a computer with internet access, may be particularly accessible for 2-year institutions with limited research capacity and significant budget constraints. To understand how GEP supports student research at CCs, we analyzed student knowledge and self-reported outcomes. We found that CC student gains are comparable to non-CC student gains, with improvements in attitudes toward science and thriving in science. Our early findings suggest that the GEP model of centralized support with flexible CURE implementation benefits CC students and may help mitigate barriers to implementing research at CCs.

Student Attitudes Contribute to the Effectiveness of a Genomics CURE

The Genomics Education Partnership (GEP) engages students in a course-based undergraduate research experience (CURE). To better understand the student attributes that support success in this CURE, we asked students about their attitudes using previously published scales that measure epistemic beliefs about work and science, interest in science, and grit. We found, in general, that the attitudes students bring with them into the classroom contribute to two outcome measures, namely, learning as assessed by a pre- and postquiz and perceived self-reported benefits. While the GEP CURE produces positive outcomes overall, the students with more positive attitudes toward science, particularly with respect to epistemic beliefs, showed greater gains. The findings indicate the importance of a student's epistemic beliefs to achieving positive learning outcomes.

Development and internal validation of clinical prediction models for outcomes of complicated intra-abdominal infection

BACKGROUND

Complicated intra-abdominal infections (cIAIs) are associated with significant morbidity and mortality. The aim of this study was to describe the clinical characteristics of patients with cIAI in a multicentre study and to develop clinical prediction models (CPMs) to help identify patients at risk of mortality or relapse.

METHODS

A multicentre observational study was conducted from August 2016 to February 2017 in the UK. Adult patients diagnosed with cIAI were included. Multivariable logistic regression was performed to develop CPMs for mortality and cIAI relapse. The c-statistic was used to test model discrimination. Model calibration was tested using calibration slopes and calibration in the large (CITL). The CPMs were then presented as point scoring systems and validated further.

RESULTS

Overall, 417 patients from 31 surgical centres were included in the analysis. At 90 days after diagnosis, 17.3 per cent had a cIAI relapse and the mortality rate was 11.3 per cent. Predictors in the mortality model were age, cIAI aetiology, presence of a perforated viscus and source control procedure. Predictors of cIAI relapse included the presence of collections, outcome of initial management, and duration of antibiotic treatment. The c-statistic adjusted for model optimism was 0.79 (95 per cent c.i. 0.75 to 0.87) and 0.74 (0.73 to 0.85) for mortality and cIAI relapse CPMs. Adjusted calibration slopes were 0.88 (95 per cent c.i. 0.76 to 0.90) for the mortality model and 0.91 (0.88 to 0.94) for the relapse model; CITL was -0.19 (95 per cent c.i. -0.39 to -0.12) and - 0.01 (- 0.17 to -0.03) respectively.

CONCLUSION

Relapse of infection and death after complicated intra-abdominal infections are common. Clinical prediction models were developed to identify patients at increased risk of relapse or death after treatment, these now require external validation.

Imaging in the investigation and management of Staphylococcus aureus bacteraemia: a role for advanced imaging techniques

Staphylococcus aureus bacteraemia (SAB) continues to affect ∼25,000 patients in the UK per year with a high crude mortality of 30% at 90 days. Prompt source control improves outcomes in sepsis and SAB and is included in sepsis guidelines. A recent clinical trial of adjunctive antibiotic treatment in SAB found that the majority of recurrences of SAB were associated with a failure of source management. In this condition, the ability to control the source of infection may be limited by the ability to detect a focus of infection. Echocardiogram is now a routinely used tool to detect such unknown foci in the form of unexpected infectious vegetations. We review the literature to explore the utility of advanced imaging techniques, such as [18F]fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and magnetic resonance imaging (including whole-body MRI), to detect foci which may otherwise be missed. As unknown foci are associated with increased mortality, we propose that increasing the detection of foci could enable improved source control and result in improved outcomes in SAB.

Facilitating Growth through Frustration: Using Genomics Research in a Course-Based Undergraduate Research Experience

A hallmark of the research experience is encountering difficulty and working through those challenges to achieve success. This ability is essential to being a successful scientist, but replicating such challenges in a teaching setting can be difficult. The Genomics Education Partnership (GEP) is a consortium of faculty who engage their students in a genomics Course-Based Undergraduate Research Experience (CURE). Students participate in genome annotation, generating gene models using multiple lines of experimental evidence. Our observations suggested that the students' learning experience is continuous and recursive, frequently beginning with frustration but eventually leading to success as they come up with defendable gene models. In order to explore our "formative frustration" hypothesis, we gathered data from faculty via a survey, and from students via both a general survey and a set of student focus groups. Upon analyzing these data, we found that all three datasets mentioned frustration and struggle, as well as learning and better understanding of the scientific process. Bioinformatics projects are particularly well suited to the process of iteration and refinement because iterations can be performed quickly and are inexpensive in both time and money. Based on these findings, we suggest that a dynamic of "formative frustration" is an important aspect for a successful CURE.

Barriers to integration of bioinformatics into undergraduate life sciences education: A national study of US life sciences faculty uncover significant barriers to integrating bioinformatics into undergraduate instruction

Bioinformatics, a discipline that combines aspects of biology, statistics, mathematics, and computer science, is becoming increasingly important for biological research. However, bioinformatics instruction is not yet generally integrated into undergraduate life sciences curricula. To understand why we studied how bioinformatics is being included in biology education in the US by conducting a nationwide survey of faculty at two- and four-year institutions. The survey asked several open-ended questions that probed barriers to integration, the answers to which were analyzed using a mixed-methods approach. The barrier most frequently reported by the 1,260 respondents was lack of faculty expertise/training, but other deterrents—lack of student interest, overly-full curricula, and lack of student preparation—were also common. Interestingly, the barriers faculty face depended strongly on whether they are members of an underrepresented group and on the Carnegie Classification of their home institution. We were surprised to discover that the cohort of faculty who were awarded their terminal degree most recently reported the most preparation in bioinformatics but teach it at the lowest rate.

Bioinformatics core competencies for undergraduate life sciences education

Although bioinformatics is becoming increasingly central to research in the life sciences, bioinformatics skills and knowledge are not well integrated into undergraduate biology education. This curricular gap prevents biology students from harnessing the full potential of their education, limiting their career opportunities and slowing research innovation. To advance the integration of bioinformatics into life sciences education, a framework of core bioinformatics competencies is needed. To that end, we here report the results of a survey of biology faculty in the United States about teaching bioinformatics to undergraduate life scientists. Responses were received from 1,260 faculty representing institutions in all fifty states with a combined capacity to educate hundreds of thousands of students every year. Results indicate strong, widespread agreement that bioinformatics knowledge and skills are critical for undergraduate life scientists as well as considerable agreement about which skills are necessary. Perceptions of the importance of some skills varied with the respondent's degree of training, time since degree earned, and/or the Carnegie Classification of the respondent's institution. To assess which skills are currently being taught, we analyzed syllabi of courses with bioinformatics content submitted by survey respondents. Finally, we used the survey results, the analysis of the syllabi, and our collective research and teaching expertise to develop a set of bioinformatics core competencies for undergraduate biology students. These core competencies are intended to serve as a guide for institutions as they work to integrate bioinformatics into their life sciences curricula.

Translocation of a gut pathobiont drives autoimmunity in mice and humans

Despite multiple associations between the microbiota and immune diseases, their role in autoimmunity is poorly understood. We found that translocation of a gut pathobiont, Enterococcus gallinarum, to the liver and other systemic tissues triggers autoimmune responses in a genetic background predisposing to autoimmunity. Antibiotic treatment prevented mortality in this model, suppressed growth of E. gallinarum in tissues, and eliminated pathogenic autoantibodies and T cells. Hepatocyte-E. gallinarum cocultures induced autoimmune-promoting factors. Pathobiont translocation in monocolonized and autoimmune-prone mice induced autoantibodies and caused mortality, which could be prevented by an intramuscular vaccine targeting the pathobiont. E. gallinarum-specific DNA was recovered from liver biopsies of autoimmune patients, and cocultures with human hepatocytes replicated the murine findings; hence, similar processes apparently occur in susceptible humans. These discoveries show that a gut pathobiont can translocate and promote autoimmunity in genetically predisposed hosts.

Short communication: Typing and tracking Bacillaceae in raw milk and milk powder using pyroprinting

Contamination of fluid and processed milk products with endospore-forming bacteria, such as Bacillaceae, affect milk quality and longevity. Contaminants come from a variety of sources, including the dairy farm environment, transportation equipment, or milk processing machinery. Tracking the origin of bacterial contamination to allow specifically targeted remediation efforts depends on a reliable strain-typing method that is reproducible, fast, easy to use, and amenable to computerized analysis. Our objective was to adapt a recently developed genotype-based Escherichia coli strain-typing method, called pyroprinting, for use in a microbial source-tracking study to follow endospore-forming bacillus bacteria from raw milk to powdered milk. A collection of endospores was isolated from both raw milk and its finished powder, and, after germination, the vegetative cells were subject to the pyroprinting protocol. Briefly, a ribosomal DNA intergenic transcribed spacer present in multiple copies in Bacillaceae genomes was amplified by the PCR. This multicopy locus generated a mixed PCR product that was subsequently subject to pyrosequencing, a quantitative real-time sequencing method. Through a series of enzymatic reactions, each nucleotide incorporation event produces a photon of light that is quantified at each nucleotide dispensation. The pattern of light peaks generated from this mixed template reaction is called a pyroprint. Isolates with pyroprints that match with a Pearson correlation of 0.99 or greater are considered to be in the same group. The pyroprint also contains some sequence data useful for presumptive species-level identification. This method identified groups with isolates from raw milk only, from powdered milk only, or from both sources. This study confirms pyroprinting as a rapid, reproducible, automatically digitized tool that can be used to distinguish bacterial strains into taxonomically relevant groups and, thus, indicate probable origins of bacterial contamination in powdered milk.

Does gender or mode of HIV acquisition affect virological response to modern antiretroviral therapy (ART)?

OBJECTIVES

Previous UK studies have reported disparities in HIV treatment outcomes for women. We investigated whether these differences persist in the modern antiretroviral treatment (ART) era.

METHODS

A single-centre cohort analysis was carried out. We included in the study all previously ART-naïve individuals at our clinic starting triple ART from 1 January 2006 onwards with at least one follow-up viral load (VL). Time to viral suppression (VS; first viral load < 50 HIV-1 RNA copies/mL), virological failure (VF; first of two consecutive VLs > 200 copies/mL more than 6 months post-ART) and treatment modification were estimated using standard survival methods.

RESULTS

Of 1086 individuals, 563 (52%) were men whose risk for HIV acquisition was sex with other men (MSM), 207 (19%) were men whose risk for HIV acquisition was sex with women (MSW) and 316 (29%) were women. Median pre-ART CD4 count and time since HIV diagnosis in these groups were 298, 215 and 219 cells/μL, and 2.3, 0.3 and 0.3 years, respectively. Time to VS was comparable between groups, but women [adjusted hazard ratio (aHR) 2.32; 95% confidence interval (CI) 1.28-4.22] and MSW (aHR 3.28; 95% CI 1.91-5.64) were at considerably higher risk of VF than MSM. Treatment switches and complete discontinuation were also more common among MSW [aHR 1.38 (95% CI 1.04-1.81) and aHR 1.73 (95% CI 0.97-3.16), respectively] and women [aHR 1.87 (95% CI 1.43-2.46) and aHR 3.20 (95% CI 2.03-5.03), respectively] than MSM.

CONCLUSIONS

Although response rates were good in all groups, poorer virological outcomes for women and MSW have persisted into the modern ART era. Factors that might influence the differences include socioeconomic status and mental health disorders. Further interventions to ensure excellent response rates in women and MSW are required.

Gut microbiota. Antimicrobial peptide resistance mediates resilience of prominent gut commensals during inflammation

Resilience to host inflammation and other perturbations is a fundamental property of gut microbial communities, yet the underlying mechanisms are not well understood. We have found that human gut microbes from all dominant phyla are resistant to high levels of inflammation-associated antimicrobial peptides (AMPs) and have identified a mechanism for lipopolysaccharide (LPS) modification in the phylum Bacteroidetes that increases AMP resistance by four orders of magnitude. Bacteroides thetaiotaomicron mutants that fail to remove a single phosphate group from their LPS were displaced from the microbiota during inflammation triggered by pathogen infection. These findings establish a mechanism that determines the stability of prominent members of a healthy microbiota during perturbation.

CMV in the gut: a critical review of CMV detection in the immunocompetent host with colitis

As scientific techniques for the detection of cytomegalovirus (CMV) improve, we are able to detect small amounts of CMV in the mucosal wall. As clinicians, we are unsure how to interpret the results of this novel test. There is controversy in the literature as to the significance of the detection of CMV in the gut. Whilst the importance of CMV and reactivation of the virus is clear in those patients such as allograft recipients with established immune compromise, the role is less clear in patients with less damaged immune systems. We explore whether the detection of CMV in such cases influences outcome and how it should be optimally managed. We discuss the optimal management of such cases, according to current guidelines, with a review of the literature.

Teaching bioinformatics in concert

Can biology students without programming skills solve problems that require computational solutions? They can if they learn to cooperate effectively with computer science students. The goal of the in-concert teaching approach is to introduce biology students to computational thinking by engaging them in collaborative projects structured around the software development process. Our approach emphasizes development of interdisciplinary communication and collaboration skills for both life science and computer science students.

A central support system can facilitate implementation and sustainability of a Classroom-based Undergraduate Research Experience (CURE) in Genomics

In their 2012 report, the President's Council of Advisors on Science and Technology advocated "replacing standard science laboratory courses with discovery-based research courses"-a challenging proposition that presents practical and pedagogical difficulties. In this paper, we describe our collective experiences working with the Genomics Education Partnership, a nationwide faculty consortium that aims to provide undergraduates with a research experience in genomics through a scheduled course (a classroom-based undergraduate research experience, or CURE). We examine the common barriers encountered in implementing a CURE, program elements of most value to faculty, ways in which a shared core support system can help, and the incentives for and rewards of establishing a CURE on our diverse campuses. While some of the barriers and rewards are specific to a research project utilizing a genomics approach, other lessons learned should be broadly applicable. We find that a central system that supports a shared investigation can mitigate some shortfalls in campus infrastructure (such as time for new curriculum development, availability of IT services) and provides collegial support for change. Our findings should be useful for designing similar supportive programs to facilitate change in the way we teach science for undergraduates.

A course-based research experience: how benefits change with increased investment in instructional time

There is widespread agreement that science, technology, engineering, and mathematics programs should provide undergraduates with research experience. Practical issues and limited resources, however, make this a challenge. We have developed a bioinformatics project that provides a course-based research experience for students at a diverse group of schools and offers the opportunity to tailor this experience to local curriculum and institution-specific student needs. We assessed both attitude and knowledge gains, looking for insights into how students respond given this wide range of curricular and institutional variables. While different approaches all appear to result in learning gains, we find that a significant investment of course time is required to enable students to show gains commensurate to a summer research experience. An alumni survey revealed that time spent on a research project is also a significant factor in the value former students assign to the experience one or more years later. We conclude: 1) implementation of a bioinformatics project within the biology curriculum provides a mechanism for successfully engaging large numbers of students in undergraduate research; 2) benefits to students are achievable at a wide variety of academic institutions; and 3) successful implementation of course-based research experiences requires significant investment of instructional time for students to gain full benefit.

Blood-stage malaria vaccines - recent progress and future challenges

Plasmodium falciparum malaria is a major global health problem, responsible for up to 1 million deaths each year. Major efforts have been made to develop an effective vaccine against this disease, to reduce the associated morbidity and mortality. There has already been considerable progress, with the first vaccine against the pre-erythrocytic stages of P. falciparum now en route to licensure. There remains, however, a strong scientific rationale for the development of a highly effective additional vaccine component against the blood stages of the parasite, which could be deployed in conjunction with partially effective control measures against the pre-erythrocytic stages. Here, recent progress in the clinical development of blood-stage vaccines is reviewed, including methods of antigen selection, the limitations of in-vitro assays for selecting vaccines for clinical development, and the results of recently published clinical trials. This review seeks to summarize recent developments in our understanding of immunity to blood-stage parasites, as well as the relevant key advances made in vaccine technologies over the last decade. The future challenges that face this field of vaccine research are also described.

The genomics education partnership: successful integration of research into laboratory classes at a diverse group of undergraduate institutions

Genomics is not only essential for students to understand biology but also provides unprecedented opportunities for undergraduate research. The goal of the Genomics Education Partnership (GEP), a collaboration between a growing number of colleges and universities around the country and the Department of Biology and Genome Center of Washington University in St. Louis, is to provide such research opportunities. Using a versatile curriculum that has been adapted to many different class settings, GEP undergraduates undertake projects to bring draft-quality genomic sequence up to high quality and/or participate in the annotation of these sequences. GEP undergraduates have improved more than 2 million bases of draft genomic sequence from several species of Drosophila and have produced hundreds of gene models using evidence-based manual annotation. Students appreciate their ability to make a contribution to ongoing research, and report increased independence and a more active learning approach after participation in GEP projects. They show knowledge gains on pre- and postcourse quizzes about genes and genomes and in bioinformatic analysis. Participating faculty also report professional gains, increased access to genomics-related technology, and an overall positive experience. We have found that using a genomics research project as the core of a laboratory course is rewarding for both faculty and students.

Undergraduate research. Genomics Education Partnership

The Genomics Education Partnership offers an inclusive model for undergraduate research experiences incorporated into the academic year science curriculum, with students pooling their work to contribute to international data bases.

Undergraduate research. Genomics Education Partnership

The Genomics Education Partnership offers an inclusive model for undergraduate research experiences incorporated into the academic year science curriculum, with students pooling their work to contribute to international data bases.

Coordinated regulation of actin filament turnover by a high-molecular-weight Srv2/CAP complex, cofilin, profilin, and Aip1

BACKGROUND

Dynamic remodeling of the actin cytoskeleton requires rapid turnover of actin filaments, which is regulated in part by the actin filament severing/depolymerization factor cofilin/ADF. Two factors that cooperate with cofilin are Srv2/CAP and Aip1. Human CAP enhances cofilin-mediated actin turnover in vitro, but its biophysical properties have not been defined, and there has been no in vivo evidence reported for its role in turnover. Xenopus Aip1 forms a cofilin-dependent cap at filament barbed ends. It has been unclear how these diverse activities are coordinated in vivo.

RESULTS

Purified native yeast Srv2/CAP forms a high molecular weight structure comprised solely of actin and Srv2. The complex is linked to actin filaments via the SH3 domain of Abp1. Srv2 complex catalytically accelerates cofilin-dependent actin turnover by releasing cofilin from ADP-actin monomers and enhances the ability of profilin to stimulate nucleotide exchange on ADP-actin. Yeast Aip1 forms a cofilin-dependent filament barbed end cap, disrupted by the cof1-19 mutant. Genetic analyses show that specific combinations of activities mediated by cofilin, Srv2, Aip1, and capping protein are required in vivo.

CONCLUSIONS

We define two genetically and biochemically separable functions for cofilin in actin turnover. One is formation of an Aip1-cofilin cap at filament barbed ends. The other is cofilin-mediated severing/depolymerization of filaments, accelerated indirectly by Srv2 complex. We show that the Srv2 complex is a large multimeric structure and functions as an intermediate in actin monomer processing, converting cofilin bound ADP-actin monomers to profilin bound ATP-actin monomers and recycling cofilin for new rounds of filament depolymerization.

Disparate actions of mifepristone (RU 486) on glands and stroma in the primate endometrium

Besides being an antiprogestin, mifepristone (RU 486) was recently shown to antagonize oestrogen-dependent growth in the endometrium. To explore the molecular mechanisms for this phenomenon, we investigated whether or not the morphological effects of mifepristone are mediated by the progesterone receptor (PR) and whether mifepristone has disparate effects on the glandular epithelium and stroma. Six groups of hypogonadal, oestrogen-primed cynomolgus monkeys were treated for 2 weeks with: vehicle only (group I); mifepristone (group II); mifepristone plus progesterone at 0.2 mg/kg (group III), 1.0 mg/kg (group IV) or 5.0 mg/kg (group V); and progesterone only (5.0 mg/kg) (group VI). Histomorphological evaluation showed strikingly compacted stroma in the mifepristone-exposed endometria (group II), which was partially reversible by additional progesterone treatment (groups III-V). Glandular proliferation (pseudostratification, glandular mitoses) in mifepristone-treated monkeys was not significantly different from that in vehicle (oestradiol)-treated monkeys, but was inhibited by progesterone-only treatment. Cells containing vacuoles were scarce in the mifepristone-exposed endometrium, but detected frequently in progesterone-exposed endometria, indicating the strong antisecretory effect of mifepristone on glands. We conclude that oestrogen-dependent oedema in the stroma is antagonized by mifepristone. The reversal of this effect by progesterone suggests a PR-mediated mechanism. In glands, mifepristone is antiprogestogenic, but not antioestrogenic. Thus, stromal cells may be the target of antiprogestin-induced inhibition of oedema and endometrial growth.

Vascular endothelial growth factor in primate endometrium is regulated by oestrogen-receptor and progesterone-receptor ligands in vivo

We investigated hormonal regulation of endometrial angiogenesis in menstruating primates. This study was designed to demonstrate: (i) that cell-specific vascular endothelial growth factor (VEGF) production and expression in monkey endometrium are regulated by steroid receptor ligands; and (ii) mifepristone (RU 486) alters VEGF production even in the absence of a progestin agonist. Endometrial VEGF production was compared by computer-assisted immunohistochemical analysis during induced hypoestrogenism and after oestradiol, progestin, or antiprogestin (mifepristone) treatment. VEGF gene expression was estimated by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) in endometrial samples from castrate cynomolgus monkeys, from intact monkeys in the luteal phase, and from monkeys treated for 20 days with levonorgestrel (LNG) or mifepristone. VEGF staining intensities in glandular epithelium and VEGF mRNA expression were highest in hypoestrogenic monkeys. Progestin treatment induced intense VEGF staining in the stroma. Gene expression of VEGF-189, but not other isoforms, was higher in progesterone- and progestin (LNG)-exposed endometria compared to mifepristone-exposed endometria or endometria from anovulatory cycles (P < 0.04). Mifepristone abolished VEGF staining in glandular epithelium almost completely. We conclude that VEGF protein and VEGF mRNA expression levels in primate endometrium depend on the steroidal milieu. Anti-angiogenic effects of mifepristone via suppression of VEGF production might represent a mechanism for its quelling effects on endometrium.

Ovarian angiogenesis in rabbits: endotheliotrophic chemoattractant activity from isolated follicles and dispersed granulosa cells

To test the hypothesis that angiogenesis is an important variable in ovarian folliculogenesis, we measured endothelial cell migration (chemotaxis) in media conditioned by rabbit ovarian cells. Endothelial cell migration, a reliable predictor of angiogenesis in vivo, was stimulated by media conditioned by isolated intact follicles (0.4-2.2 mm in diameter) from either unstimulated or hCG-stimulated (pseudopregnant) rabbits. In separate experiments, endothelial cell migration was also stimulated by granulosa cell-conditioned media. Follicular chemoattractant activity was associated with a molecular weight greater than 30,000 but was not correlated with follicular size or steroid concentrations in the media, although there was no evidence to suggest that the biological activity detected in media conditioned by either intact follicles or dispersed granulosa cells was the same. Demonstration of nonsteroidal chemoattractant activity in media conditioned by intact follicles or by dispersed granulosa cells provides evidence that follicles secrete a vascular chemotactic factor, and is consistent with a role for angiogenesis in follicle growth.

Evidence for the production of a nonsteroidal endotheliotropic factor by human granulosa cells in culture

OBJECTIVE

To determine the cellular source of the angiogenic activity displayed by follicular fluid (FF).

DESIGN

Human granulosa cells were harvested from 27 follicular aspirates obtained 34 to 36 hours after eight patients, previously treated with human menopausal gonadotropin (hMG), follicle-stimulating hormone plus hMG, or clomiphene citrate and hMG received human chorionic gonadotropin (10,000 IU intramuscularly). Granulosa cells from individual follicles were plated at 50,000 cells/cm2 in Medium 199 (Sigma, St. Louis, MO) supplemented with either 5% calf serum or 0.1% bovine serum albumin; media collected 24 hours later was assayed in vitro measuring endothelial cell migration. Fractions depleted of steroids by reversed phase C1 chromatography were assayed as well.

RESULTS

Granulosa cell-conditioned media from 18 of 27 follicles significantly stimulated endothelial cell migration (P less than 0.05). Chemoattractant activity did not appear to be related to steroid accumulation in the media and was not diminished in steroid depleted fractions.

CONCLUSIONS

These findings suggest that human granulosa cells are a source of (nonsteroidal) endotheliotropic-angiogenic activity in FF.

Preliminary characterization of angiogenic activity in media conditioned by cells from luteinized rat ovaries

Angiogenic activity was detected in media conditioned by ovarian cells from superovulated, pseudopregnant (PMSG/human CG treated) immature Holtzman rats. Media conditioned by cells from luteinized rat ovaries stimulated the directed migration of rabbit endothelial cells or mouse Balb/c3T3 cells, but was not mitogenic to either cell type. That endotheliotropic activity was not associated with a steroid was indicated by the finding that chemoattractant activity was detected in fractions after reversed-phase C18 chromatography, which removes more than 95% of steroids present in the media, and that chemoattractant activity was precipitated by ammonium sulfate and by ethanol. Full chemoattractant activity was recovered after boiling (95 C for 30 min), lyophilization, dialysis, Sephadex G-25 desalting columns, and pH changes from 3-10. After Sephadex G-200 chromatography, chemoattractant activity emerged at elution volumes corresponding to 20,000-30,000 mol wt. Chemoattractant activity was not retained by Concanavalin A-Sepharose or gelatin-Sepharose, and was only partially retained by heparin-agarose. Chemoattractant activity was also partially retained on both cation and anion exchange columns. Our collective findings indicate the presence of a nonsteroidal, heat-stable, pronase-sensitive factor, nominal mol wt of 20,000-30,000, in media conditioned by cells from luteinized rat ovaries; this factor is chemoattractive but not mitogenic to endothelial cells. Ovarian-derived chemoattractant activity appears to be distinct from fibroblast growth factor because it lacked detectable mitogenic activity, and because fibroblast growth factor was not active in our cell migration bioassay. Because stimulation of endothelial cell migration is a key event during angiogenesis, demonstration of an ovarian endotheliotropic chemoattractant is consistent with our hypothesis that angiogenesis factors play a role in the paracrine regulation of ovarian function.

Use of the levator scapulae muscle flap in head and neck reconstruction

There are numerous techniques available for reconstruction of defects following composite resection of oral cavity and oropharyngeal tumors. No single technique is applicable in all situations. The levator scapulae muscle flap is well known for its application in carotid protection. Little attention is paid to its usefulness in other aspects of head and neck reconstruction. We have been using the levator scapulae muscle flap for a variety of reconstructive problems. The flap is useful for buttressing intraoral suture lines, closing intraoral defects, and providing soft tissue to fill in dead spaces and bulk out lateral and anterior oral defects. The levator flap was found to be easy to elevate, safe, and reliable with a minimum of wound complications. A review of 18 patients, representative case studies, and a discussion of surgical technique and relevant anatomy and blood supply is presented.

Thyroid angiogenesis: endotheliotropic chemoattractant activity from rat thyroid cells in culture

Thyroid enlargement in response to chronic hypersecretion of TSH reflects the coordinated growth of both parenchyma and stroma. Because Wollman et al. observed in propylthiouracil-fed rats that enlargement and remodeling of thyroid capillaries were strictly localized around follicles, they hypothesized that growth of perifollicular blood vessels is stimulated by angiogenic factors secreted by neighboring follicular epithelial cells. In support of this hypothesis, we report that media conditioned by rat thyroid cells were very active in an in vitro angiogenesis bioassay that measures stimulation of endothelial cell migration through chemotaxis membranes in microwell Boyden chamber assemblies. Primary cultures of thyroid cells from collagenase-dispersed glands from male or female Holtzman rats fed 0.01% propylthiouracil in the drinking water released activity that produced up to 5-fold increases in endothelial cell migration rates relative to those in identical unconditioned medium. Thyroid-derived activity was primarily chemotactic (i.e. only weakly chemokinetic) to both rabbit aortic and microvascular endothelial cells. That endotheliotropic activity is derived from thyroid parenchyma is indicated by the finding that media conditioned by FRTL cells, a clonally derived thyroid follicular epithelial cell line, produced parallel chemoattractant responses. Thyroid-conditioned media were also chemoattractant to mouse BALB/c-3T3 cells, which have endothelial cell characteristics. In contrast, thyroid-conditioned media did not increase the high spontaneous migration rate of Walker rat sarcoma (WR256) cells. T4, T3, thyroglobulin, bovine fibroblast growth factor (alpha and beta), and media conditioned by rabbit endothelial cells were inactive. Chemoattractant activity in serum containing conditioned media was retained by both 10,000 and 30,000 mol wt cut-off (MWCO) ultrafilters. Activity in serum-free thyroid-conditioned media was largely retained by 10,000 MWCO filters, but only partially retained by 30,000 MWCO filters; activity in the 30,000 filtrate was recoverable in a 10,000 MWCO retentate. These findings support the hypothesis that capillary growth during thyroid enlargement occurs, at least in part, as a result of a parenchymal-stromal (epithelial-mesenchymal) paracrine interaction mediated by specific endotheliotropic (angiogenic) factors released by follicular epithelial cells and distinct from T3, T4, and thyroglobulin.

Sequence of reconstitution of seven basement-membrane components following split-thickness wound induction in primate skin

Recent studies have shown an orderly sequence of expression of structural antigens within the skin basement-membrane zone of the human fetus. Interestingly, these findings differ from those reported following split-thickness would induction in Yorkshire pigs. To readdress this apparent disparity, as well as to further extend such studies to include other basement-membrane antigens more recently identified, we produced split-thickness wounds in a primate species and serially examined the wounds by immunofluorescence technique for the expression of seven antigens normally found in intact primate skin basement membrane. By the fourth day following wounding, laminin, type-IV collagen, and fibronectin were all detectable along the dermoepidermal junction. In contrast, bullous pemphigoid antigen, epidermolysis bullosa acquisita antigen, cicatricial pemphigoid antigen, and KF-1 antigen were undetectable until days 6, 8, 10, and 11, respectively. These latter findings are in complete agreement with those previously reported in the developing human fetus. On the basis of the results of this study, we would suggest that primate rather than pig skin may be a more appropriate animal model for wound-healing studies. These data are consistent with previous reports suggesting that the basement-membrane antigens recognized by bullous pemphigoid and cicatricial pemphigold autoantibodies are indeed distinct. Finally, these data bring into question the functional role of bullous pemphigoid antigen during the early phase of wound healing in humans.

Heterogeneity of rabbit aortic endothelial cells in primary culture

Factor VIII-related antigen (F8-RAg) and angiotensin-converting enzyme (ACE) are accepted diagnostic markers of endothelial cells in culture. However, when we isolated cells from rabbit thoracic aorta (after collagenase treatment and gentle scraping of the intima) and examined them with immunoperoxidase techniques, we observed two cell types which stained specifically for either F8-RAg or ACE, but not both. Each cell type was morphologically distinguishable in primary culture. F8-RAg-positive cells were recognizable in distinct patches as more elongated, tightly apposed, and firmly adherent cells; they exhibited only faint or no staining for ACE and no accumulation of a fluorescent, acetylated low-density lipoprotein probe (DiI-Ac-LDL), another endothelial cell marker. In contrast, ACE-positive cells were more rounded, less closely apposed, and grew as strict monolayers that exhibited a characteristic cobblestone appearance at confluence; ACE-positive cells were F8-RAg negative, but demonstrated intense labeling with DiI-Ac-LDL. Subcultures of ACE-positive cells were also stained by anti-rabbit thrombomodulin.