Simultaneous measurement of urinary albumin and total protein may facilitate decision-making in HIV-infected patients with proteinuria

OBJECTIVE

We recently showed that a urine albumin/total protein ratio (uAPR) <0.4 identifies tubular pathology in proteinuric patients. In tubular disorders, proteinuria is usually of low molecular weight and contains relatively little albumin. We tested the hypothesis that uAPR is useful in identifying tubular pathology related to antiretroviral use in HIV-infected patients.

METHODS

We retrospectively identified urine protein/creatinine ratios (uPCRs) in HIV-infected patients. A subset of samples had uPCR and urine albumin/creatinie ratio (uACR) measured simultaneously. We classified proteinuric patients (uPCR >30 mg/mmol) into two groups: those with predominantly 'tubular' proteinuria (TP) (uAPR <0.4) and those with predominantly 'glomerular' proteinuria (GP) (uAPR ≥ 0.4).

RESULTS

A total of 618 of 5244 samples from 1378 patients had uPCR ≥ 30 mg/mmol. uAPRs were available in 144 patients: 46 patients (32%) had TP and 21 (15%) GP; the remainder had uPCR <30 mg/mmol. The TP group had a higher fractional excretion of phosphate compared with the GP group (mean 27% vs. 16%, respectively; P<0.01). Patients with TP were more likely to be on tenofovir and/or a boosted protease inhibitor compared with those with GP. In 18 patients with heavy proteinuria (uPCR >100 mg/mmol), a renal assessment was made; eight had a kidney biopsy. In all cases, the uAPR results correlated with the nephrological diagnosis.

CONCLUSIONS

In HIV-infected patients, measuring uAPR may help to identify patients in whom a renal biopsy is indicated, and those in whom tubular dysfunction might be an important cause of proteinuria and which may be related to antiretroviral toxicity. We suggest that this would be useful as a routine screening procedure in patients with proteinuria.

Increased expression of Syne1/nesprin-1 facilitates nuclear envelope structure changes in embryonic stem cell differentiation

We found by electron microscopy that the inter-membrane space of embryonic stem cells is irregular and generally wider than in differentiated cells. Among a panel of nuclear envelope structural proteins examined, the expression of Syne1/nesprin-1 was found to be greatly induced upon differentiation. Down-regulation of Syne1 by siRNA in differentiated embryonic stem cells caused the nuclear envelope to adopt a configuration resembling that found in undifferentiated embryonic stem cells. Suppression of Syne1 expression did not produce a detectable impact on the retinoic acid-induced differentiation of embryonic stem cells; however, forced expression of Syne1 enhanced the tendency of the cells to lose pluripotency. Thus, we found that low expression of Syne1 splicing isoforms accounts for the wider and irregular nuclear envelope inter-membrane space in embryonic stem cells. We conclude that the nuclear envelope structural change accompanying differentiation likely participates in promoting the differential chromatin organization of the differentiated cells.

The equivalence between volume averaging and method of planes definitions of the pressure tensor at a plane

It is shown analytically that the method of planes (MOP) [Todd, Evans, and Daivis, Phys. Rev. E 52, 1627 (1995)] and volume averaging (VA) [Cormier, Rickman, and Delph, J. Appl. Phys. 89, 99 (2001)] formulas for the local pressure tensor, P(α, y)(y), where α ≡ x, y, or z, are mathematically identical. In the case of VA, the sampling volume is taken to be an infinitely thin parallelepiped, with an infinite lateral extent. This limit is shown to yield the MOP expression. The treatment is extended to include the condition of mechanical equilibrium resulting from an imposed force field. This analytical development is followed by numerical simulations. The equivalence of these two methods is demonstrated in the context of non-equilibrium molecular dynamics (NEMD) simulations of boundary-driven shear flow. A wall of tethered atoms is constrained to impose a normal load and a velocity profile on the entrained central layer. The VA formula can be used to compute all components of P(αβ)(y), which offers an advantage in calculating, for example, P(xx)(y) for nano-scale pressure-driven flows in the x-direction, where deviations from the classical Poiseuille flow solution can occur.

Tick communities at the expanding wildlife/cattle interface in the Eastern Cape Province, South Africa: implications for Corridor disease

Corridor disease, transmitted by the brown ear tick (Rhipicephalus appendiculatus), is one of Africa's most pathogenic tick-borne diseases for cattle. With a focus on this species, we investigated the community parameters (richness, diversity and abundance) of ticks in the Eastern Cape, South Africa, and how this may be linked to the increasing wildlife/cattle interface in the region. There were significantly more ticks of a greater diversity and richness at sites positioned at the wildlife/cattle interface ('treatment sites') compared to sites where wildlife was absent (controls). Significantly, R. appendiculatus was only found at the treatment sites. Therefore, it is believed that the wildlife/cattle interface may be playing a crucial role in increasing the occurrence, abundance and distribution of R. appendiculatus in the Eastern Cape. The implications of a Corridor disease outbreak in the region are discussed.

Complex spinal-paraspinal fast-flow lesions in CLOVES syndrome: analysis of clinical and imaging findings in 6 patients

CLOVES syndrome is a complex disorder of congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal/scoliosis/spinal anomalies. We report the occurrence of spinal-paraspinal fast-flow lesions within or adjacent to the truncal overgrowth or a cutaneous birthmark in 6 patients with CLOVES syndrome.

Nuclear entry of activated MAPK is restricted in primary ovarian and mammary epithelial cells

Background

The MAPK/ERK1/2 serine kinases are primary mediators of the Ras mitogenic signaling pathway. Phosphorylation by MEK activates MAPK/ERK in the cytoplasm, and phospho-ERK is thought to enter the nucleus readily to modulate transcription.

Principal Findings

Here, however, we observe that in primary cultures of breast and ovarian epithelial cells, phosphorylation and activation of ERK1/2 are disassociated from nuclear translocalization and transcription of downstream targets, such as c-Fos, suggesting that nuclear translocation is limited in primary cells. Accordingly, in import assays in vitro, primary cells showed a lower import activity for ERK1/2 than cancer cells, in which activated MAPK readily translocated into the nucleus and activated c-Fos expression. Primary cells express lower levels of nuclear pore complex proteins and the nuclear transport factors, importin B1 and importin 7, which may explain the limiting ERK1/2 import found in primary cells. Additionally, reduction in expression of nucleoporin 153 by siRNA targeting reduced ERK1/2 nuclear activity in cancer cells.

Conclusion

ERK1/2 activation is dissociated from nuclear entry, which is a rate limiting step in primary cells and in vivo, and the restriction of nuclear entry is disrupted in transformed cells by the increased expression of nuclear pores and/or nuclear transport factors.

A novel association between RASA1 mutations and spinal arteriovenous anomalies

BACKGROUND AND PURPOSE

CM-AVM is a recently recognized autosomal dominant disorder associated with mutations in RASA1. Arteriovenous lesions have been reported in the brain, limbs, and the face in 18.5% of patients. We report a novel association between RASA1 mutations and spinal arteriovenous anomalies.

MATERIALS AND METHODS

In a collaborative study, 5 index patients (2 females, 3 males) with spinal AVMs or AVFs and cutaneous multifocal capillary lesions were investigated for the RASA1 gene mutation.

RESULTS

All 5 patients were found to have RASA1 mutation (2 de novo, 3 familial), and all had multifocal capillary malformations at birth. Neurologic deficits developed at ages ranging from infancy to early adulthood. All spinal anomalies (2 AVMs at the conus, 1 AVM at the lumbosacral junction, and 1 cervical and 1 cervicothoracic AVF) were complex, extensive, and fast-flow lesions. All patients required treatment based on the clinical and/or radiologic appearance of the lesions.

CONCLUSIONS

To our knowledge, an association of RASA1 mutation and spinal AVM/AVF has not been described. MR imaging screening of patients with characteristic CMs and neurologic symptoms presenting at a young age may be useful in detecting the presence of fast-flow intracranial or intraspinal arteriovenous anomalies before potentially significant neurologic insult has occurred.

Environmental integrated assessment via Monte Carlo simulation with a case study of the Mid-Atlantic region, USA

Environmental integrated assessments are often carried out via the aggregation of a set of environmental indicators. Aggregated indices derived from the same data set can differ substantially depending upon how the indicators are weighted and aggregated, which is often a subjective matter. This article presents a method of generating aggregated environmental indices in an objective manner via Monte Carlo simulation. Rankings derived from the aggregated indices within and between three Monte Carlo simulations were used to evaluate the overall environmental condition of the study area. Other insights, such as the distribution of good or bad values of indicators at a watershed and/or a subregion, were observed in the study.

Loss of GATA4 and GATA6 expression specifies ovarian cancer histological subtypes and precedes neoplastic transformation of ovarian surface epithelia

BACKGROUND

The family of zinc finger-containing GATA transcription factors plays critical roles in cell lineage specification during early embryonic development and organ formation. GATA4 and GATA6 were found to be frequently lost in ovarian cancer, and the loss is proposed to account for dedifferentiation of the cancer cells.

METHODOLOGY/PRINCIPAL FINDINGS

We further investigated the expression of GATA4 and GATA6 in ovarian surface epithelial lesions and histological subtypes of ovarian carcinomas by immunostaining. GATA4 and GATA6 were found to be absent in high percentages (80 to 90%) of serous, clear cell, and endometrioid ovarian cancer examined. In contrast, both were found positive in 11 out of 12 cases of mucinous carcinomas, suggesting the expression of the GATA factors can distinguish mucinous cancer from other histological subtypes. GATA4 was frequently lost in preneoplastic lesions such as morphologically normal inclusion cysts and epithelial hyperplasia adjacent to malignant cells. The loss of GATA6 correlates closely with neoplastic morphological transformation of ovarian surface epithelia. In culture, GATA4 expression was progressively reduced upon passaging primary ovarian surface epithelial cells, which correlated with changes in histone modification of the GATA4 locus. A reduced GATA6 gene dosage as in GATA6 (+/-) mice led to an increased pre-neoplastic changes and inclusion cysts in the ovaries, suggesting the loss of GATA6 contributes to ovarian cancer development.

CONCLUSIONS/SIGNIFICANCE

This study suggests that the expression status of GATA4 and GATA6 may dictate distinct pathologic pathways leading to serous or mucinous ovarian carcinomas. The readily loss of GATA4 expression through changes in chromatin conformation suggests a potential non-phenotypic initiating event, leading to subsequent loss of GATA6, morphological transformation, and ultimate tumorigenesis.

C-Fos elimination compensates for disabled-2 requirement in mouse extraembryonic endoderm development

Disabled-2 (Dab2) is expressed in primitive endoderm cells as they are differentiating from the inner cell mass and dab2 deficiency in mice results in lethality at E5.5-E6.5 due to the disorganization of the endoderm layers. Here we show that Dab2 suppresses c-Fos expression in endoderm cells. A morphological normal primitive endoderm layer was observed in putative E5.5 dab2 (-/-):c-fos (-/-) embryos, indicating that the primitive endoderm defect due to the loss of Dab2 is rescued by deletion of the c-fos gene. The lethality of the double knockout embryos was delayed until E9.5-E10.5 and the defective embryos failed to undergo organogenesis. We conclude that Dab2 plays a role in epithelial organization by suppression of c-Fos expression and suggest that unsuppressed c-Fos can lead to disruption of primitive endoderm epithelial organization, yet an additional dab2 function is required for later organogenesis.

Infantile hemangiomas involving the neuraxis: clinical and imaging findings

BACKGROUND AND PURPOSE

The neuroradiology and neurosurgery literature is replete with references to "hemangioma" involving the central nervous system (CNS). However, the number of cases of true infantile hemangiomas in the CNS reported to date is 15. Our purpose was to delineate the definition of infantile hemangiomas, determine their prevalence in the neuraxis, and describe their imaging characteristics and associations in this location.

MATERIALS AND METHODS

We reviewed our Vascular Anomalies Center data base from 1999 through May 2008 to assess the prevalence of intracranial or intraspinal involvement within the total cohort of infantile hemangiomas. Fifteen patients were identified with infantile hemangiomas that involved the neuraxis. Two board-certified neuroradiologists reviewed the available imaging of these 15 patients, and a board-certified pathologist reviewed the available histopathology. Clinical records of all 15 patients were reviewed to identify the type of treatment and the treatment response.

RESULTS

Of the 1454 patients listed with infantile hemangioma, 15 (approximately 1.0%) had involvement of the CNS. Eight patients had intracranial infantile hemangioma, 6 had intraspinal hemangioma, and 1 had both. In most instances, there was continuous extension into the neuraxis from an extracranial or extraspinal lesion. There were no cases of a CNS hemangioma without an accompanying extra-CNS tumor. Two patients had findings consistent with posterior fossa anomalies, cervicofacial hemangioma, arterial anomalies, cardiac defects, ocular abnormalities, and associated sternal or ventral defect. Of note, there were no brain or spinal parenchymal signal-intensity abnormalities, and there was no evidence of parenchymal invasion.

CONCLUSIONS

CNS involvement by infantile hemangiomas is an unusual occurrence, which, when recognized, can help optimize patient management.

Ovarian ageing, follicle depletion, and cancer: a hypothesis for the aetiology of epithelial ovarian cancer involving follicle depletion

The association between ovarian cancer risk and reproductive factors has been well established, and two main theories, incessant ovulation and gonadotropin stimulation, have been proposed to explain the mechanism. Recent studies using animal models of ovarian tumorigenesis, and analysis of ovarian tissues from prophylactic oophorectomies, suggest that depletion of ovarian follicles might underlie the epidemiological findings linking reproductive history and ovarian cancer risk.

Effects of subthalamic deep brain stimulation on noun/verb generation and selection from competing alternatives in Parkinson's disease

BACKGROUND AND AIMS

Impaired generation of verbs relative to nouns has been reported in Parkinson's disease (PD) and has been associated with the frontal pathophysiology of PD. The aim of the present study was to measure noun/verb generation abilities in PD and to determine whether noun/verb generation is affected by stimulation of the subthalamic nucleus (STN).

PATIENTS AND METHODS

8 participants who had been diagnosed with PD and had received surgery for deep brain stimulation (DBS) of the STN as well as 15 control participants completed a noun/verb generation task with four probe-response conditions-namely, noun-noun, verb-noun, noun-verb and verb-verb conditions. Patients with PD were assessed while receiving STN stimulation and without stimulation.

RESULTS

During the off stimulation condition, patients with PD presented with a selective deficit in verb generation compared with control participants. However, when receiving STN stimulation, patients with PD produced significantly more errors than controls during the noun-noun and verb-verb conditions, supporting evidence from previous studies that STN stimulation modulates a frontotemporal network associated with word generation. Finally, errors during verb generation were significantly correlated with item selection constraint (ie, the degree to which a response competes with other response alternatives) in the on stimulation condition, but not the off stimulation condition.

CONCLUSION

Our results suggest that STN stimulation affects the ability to select from many competing lexical alternatives during verb generation.

Cell autonomous sorting and surface positioning in the formation of primitive endoderm in embryoid bodies

The differentiation and formation of the primitive endoderm in early embryos can be mimicked in vitro by the aggregation of embryonic stem cells to form embryoid bodies. We present morphological evidence that primitive endoderm cells often first locate in the interior of embryoid bodies and subsequently migrate to the surface. Cell mixing experiments indicate that surface positioning is an intrinsic property of endoderm epithelial cells. Moreover, Disabled-2 (Dab2) is required for surface sorting and positioning of the endoderm cells: when Dab2 expression was eliminated, the differentiated endoderm epithelial cells distributed throughout the interior of the embryoid bodies. Surprisingly, E-cadherin is dispensable for primitive endoderm differentiation and surface sorting in embryoid bodies. These results support the model that primitive endoderm cells first emerge in the interior of the inner cell mass and are subsequently sorted to the surface to form the primitive endoderm.

A reduction of cyclooxygenase 2 gene dosage counters the ovarian morphological aging and tumor phenotype in Wv mice

Menopausal ovaries undergo morphological changes, known as ovarian aging, which are implicated in the high incidence of ovarian cancer occurring during the perimenopausal and immediate postmenopausal periods. The germ cell-deficient Wv mice recapitulate these postmenopausal alterations in ovarian morphology and develop tubular adenomas. We demonstrate that a reduction of cyclooxygenase 2 gene dosage rescued the ovarian aging phenotype of the Wv mice, whereas homozygous deletion was accompanied by a compensatory increase in ovarian cyclooxygenase 1 expression and prostaglandin E(2) synthesis. Cyclooxygenase inhibitors also reduced the tumor phenotype in a preliminary study. These findings suggest that increased cyclooxygenase activity contributes to the preneoplastic morphological changes of the ovarian surface epithelium, which can be reversed by a reduction of gene dosage achieved by either genetic or pharmacological approaches.

Sensitivity analysis of aggregated indices for integrated assessment with a case study of the Mid-Atlantic region

Environmental indicators are often aggregated into a single index for various purposes in environmental studies. Aggregated indices derived from the same data set can differ, usually because the aggregated indices' sensitivities are not thoroughly analyzed. Furthermore, if a sensitivity analysis is carried out, it is not presented in a transparent fashion to policy decision-makers. This paper presents a method of generating various aggregated environmental indices and analyzing their sensitivities via the use of the fuzzy set concept. Results show that several insights into the environmental conditions of the study area (e.g., the distribution of good or bad values of indicators at a watershed and or across the region) can be revealed in the sensitivity analysis of aggregated indices.

Disabled-2 is an epithelial surface positioning gene

The formation of the primitive endoderm layer on the surface of the inner cell mass is one of the earliest epithelial morphogenesis in mammalian embryos. In mouse embryos deficient of Disabled-2 (Dab2), the primitive endoderm cells lose the ability to position on the surface, resulting in defective morphogenesis. Embryonic stem cells lacking Dab2 are also unable to position on the surface of cell aggregates and fail to form a primitive endoderm outer layer in the embryoid bodies. The cellular function of Dab2, a cargo-selective adaptor, in mediating endocytic trafficking of clathrin-coated vesicles is well established. We show here that Dab2 mediates directional trafficking and polarized distribution of cell surface proteins such as megalin and E-cadherin and propose that loss of polarity is the underlying mechanism for the loss of epithelial cell surface positioning in Dab2-deficient embryos and embryoid bodies. Thus, the findings indicate that Dab2 is a surface positioning gene and suggest a novel mechanism of epithelial cell surface targeting.

Disabled-2 heterozygous mice are predisposed to endometrial and ovarian tumorigenesis and exhibit sex-biased embryonic lethality in a p53-null background

Disabled-2 (Dab2) is a phosphoprotein involved in cellular signal transduction and endocytic trafficking. The expression of Dab2 is frequently lost or suppressed in several epithelial tumors, and studies of its cellular function and growth suppressive activity when re-expressed in cancer cells led to the suggestion that Dab2 is a tumor suppressor. A role for Dab2 in epithelial cell positioning organization was derived from study of knockout mice: homozygous deletion of dab2 results in early embryonic lethality due to the disorganization of the primitive endoderm, the first epithelium in early embryos. We now report that dab2 heterozygous mice develop uterine hyperplasia and ovarian preneoplastic morphological changes at a high frequency. Crossing into a p53(-/-) background unexpectedly produced few female dab2(+/-):p53(-/-) mice, while the male dab2(+/-):p53(-/-) were born at the expected Mendelian frequency. The tumor-prone phenotype of dab2(+/-) mice provides additional support for a role of human Dab2 as a tumor suppressor, and the sex-biased embryonic lethality suggests a genetic interaction between p53 and dab2 genes in female mice.

Diagnosis and treatment frequency for overweight children and adolescents at well child visits

Obesity in children is a rapidly growing problem and may be underrecognized by pediatricians. We reviewed 473 consecutive well child visits to assess frequency of correctly identifying overweight children. Of children with a body mass index greater than the 95th percentile for gender and age, only 27 (29%) were diagnosed as overweight by the physician. Our results suggest that the frequency of diagnosing children as overweight at well child visits is critically low.

Integrated environmental assessment of the Mid-Atlantic region with analytical network process

A decision analysis method for integrating environmental indicators was developed. This was a combination of Principal Component Analysis (PCA) and the Analytic Network Process (ANP). Being able to take into account the interdependency among variables, the method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic Region of the United States, we were able to point out areas which were in relatively poor condition and/or vulnerable to future deterioration regarding various environmental aspects. The method offered an easy and comprehensive way to combine the strengths of conventional multivariate statistics (PCA) and decision-making science tool (ANP) for integrated environmental assessment.

An overview of data integration methods for regional assessment

The U.S. Environmental Protections Agency's (U.S. EPA) Regional Vulnerability Assessment(ReVA) program has focused much of its research over the last five years on developing and evaluating integration methods for spatial data. An initial strategic priority was to use existing data from monitoring programs, model results, and other spatial data. Because most of these data were not collected with an intention of integrating into a regional assessment of conditions and vulnerabilities, issues exist that may preclude the use of some methods or require some sort of data preparation. Additionally, to support multi-criteria decision-making, methods need to be able to address a series of assessment questions that provide insights into where environmental risks are a priority. This paper provides an overview of twelve spatial integration methods that can be applied towards regional assessment, along with preliminary results as to how sensitive each method is to data issues that will likely be encountered with the use of existing data.

Using science to assess environmental vulnerabilities

Beginning in 1995, the U.S. Environmental Protection Agency (U.S. EPA), Office of Research and Development has focused much of its ecological research in the Mid-Atlantic as part of the Mid-Atlantic Integrated Assessment (MAIA). The goal of MAIA is to improve the assessability of scientific information in environmental decision-making. Following the Environmental Monitoring and Assessment Program (EMAP) whose goal is to guide monitoring that effectively reflects current ecosystem condition and trends, MAIA's second, current, phase of research under the Regional Vulnerability Assessment (ReVA) program is designed to target risk management activities using available data and models. The papers presented here are from a conference held in May 2003 that presented results of research in this second phase of MAIA. The conference was organized into the following topics: 1. Assessing Current Impacts and Vulnerabilities 2. Forecasting Environmental Condition and Vulnerabilities 3. Developing Management Strategies to Optimize the Future, and 4. Assessing and Responding to Environmental Vulnerability.

Regulation of Ras-MAPK pathway mitogenic activity by restricting nuclear entry of activated MAPK in endoderm differentiation of embryonic carcinoma and stem cells

In response to retinoic acid, embryonic stem and carcinoma cells undergo differentiation to embryonic primitive endoderm cells, accompanied by a reduction in cell proliferation. Differentiation does not reduce the activation of cellular MAPK/Erk, but does uncouple mitogen-activated protein kinase (MAPK) activation from phosphorylation/activation of Elk-1 and results in inhibition of c-Fos expression, whereas phosphorylation of the cytoplasmic substrate p90RSK remains unaltered. Cell fractionation and confocal immunofluorescence microscopy demonstrated that activated MAPK is restricted to the cytoplasmic compartment after differentiation. An intact actin and microtubule cytoskeleton appears to be required for the restriction of MAPK nuclear entry induced by retinoic acid treatment because the cytoskeletal disrupting agents nocodazole, colchicine, and cytochalasin D are able to revert the suppression of c-Fos expression. Thus, suppression of cell proliferation after retinoic acid–induced endoderm differentiation of embryonic stem and carcinoma cells is achieved by restricting nuclear entry of activated MAPK, and an intact cytoskeleton is required for the restraint.

Self-organizing maps for integrated environmental assessment of the Mid-Atlantic region

A new method has been developed to perform environmental assessment at regional scale. This involves a combination of a self-organizing map (SOM) neural network and principal component analysis (PCA). The method is capable of clustering ecosystems in terms of environmental conditions and suggesting relative cumulative environmental impacts of multiple factors across a large region. Using data on land-cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, the method was able to indicate areas that are in relatively poor environmental condition or vulnerable to future deterioration. Combining the strengths of SOM with those of PCA, the method offers an easy and useful way to perform a regional environmental assessment. Compared with traditional clustering and ranking approaches, the described method has considerable advantages, such as providing a valuable means for visualizing complex multidimensional environmental data at multiple scales and offering a single assessment or ranking needed for a regional environmental assessment while still facilitating the opportunity for more detailed analyses.

Disabled-2 is essential for endodermal cell positioning and structure formation during mouse embryogenesis

The signal transduction adapter protein Disabled-2 (Dab2) is one of the two mammalian orthologs of the Drosophila Disabled. The brain-specific Disabled-1 (Dab1) functions in positional organization of brain cells during development. Dab2 is widely distributed and is highly expressed in many epithelial cell types. The dab2 gene was interrupted by in-frame insertion of beta-galactosidase (LacZ) in embryonic stem cells and transgenic mice were produced. Dab2 expression was first observed in the primitive endoderm at E4.5, immediately following implantation. The homozygous Dab2-deficient mutant is embryonic lethal (earlier than E6.5) due to defective cell positioning and structure formation of the visceral endoderm. In E5.5 dab2 (-/-) conceptus, visceral endoderm-like cells are present in the deformed primitive egg cylinder; however, the visceral endoderm cells are not organized, the cells of the epiblast have not expanded, and the proamniotic cavity fails to form. Disorganization of the visceral endodermal layer is evident, as cells with positive visceral endoderm markers are scattered throughout the dab2 (-/-) conceptus. Only degenerated remains were observed at E6.5 for dab2 (-/-) embryos, and by E7.5, the defective embryos were completely reabsorbed. In blastocyst in vitro culture, initially cells with characteristics of endoderm, trophectoderm, and inner cell mass were observed in the outgrowth of the hatched dab2 (-/-) blastocysts. However, the dab2 (-/-) endodermal cells are much more dispersed and disorganized than those from wild-type blastocysts, the inner cell mass fails to expand, and the outgrowth degenerates by day 7. Thus, Dab2 is required for visceral endodermal cell organization during early mouse development. The absence of an organized visceral endoderm in Dab2-deficient conceptus leads to the growth failure of the inner cell mass. We suggest that Dab2 functions in a signal pathway to regulate endodermal cell organization using endocytosis of ligands from the blastocoel cavity as a positioning cue.

Ras/MAPK pathway confers basement membrane dependence upon endoderm differentiation of embryonic carcinoma cells

The formation of extraembryonic endoderm is one of the earliest steps in the differentiation of pluripotent cells of the inner cell mass during the early stages of embryonic development. The primitive endoderm cells and the derived parietal and visceral endoderm cells gain the capacity to produce collagen IV and laminin. The deposition of these components results in the formation of basement membrane and epithelium of the endoderm, with polarized cells covering the inner surface of the blastocoels. We used retinoic acid-induced endoderm differentiation of stem cell-like F9 embryonic carcinoma cells to study the role of the Ras pathway and its regulation in the formation of the visceral endoderm. Upon endoderm differentiation of F9 cells induced by retinoic acid, c-Fos expression, the downstream target of the Ras pathway, is suppressed by uncoupling Elk-1 phosphorylation/activation to MAPK activity. However, attachment to matrix gel greatly enhances the activation of MAPK in endoderm cells but not in undifferentiated F9 cells. Enhanced MAPK activation as a result of contact with basement membrane is able to compensate for reduced Elk-1 phosphorylation and c-Fos expression. We conclude that endoderm differentiation renders the activation of the Ras pathway basement membrane dependent, contributing to the epithelial organization of the visceral endoderm.

Dynamic alterations of the extracellular environment of ovarian surface epithelial cells in premalignant transformation, tumorigenicity, and metastasis

BACKGROUND

Ovarian surface epithelial cells are positionally organized as a single cell layer by a sheet of basement membrane. It is believed that the contact of the ovarian surface epithelial cells with the basement membrane regulates cell growth and ensures the organization of the epithelium. Disabled-2 (Dab2), a signal transduction protein and a candidate tumor suppressor of ovarian carcinoma, functions in positional organization of ovarian surface epithelial cells. In ovarian carcinomas, genetic and epigenetic changes enable the tumor cells to escape positional control and proliferate in a disorganized fashion. Alterations in the extracellular environment may also be critical for tumor initiation and progression.

METHODS

We analyzed and compared the presence of collagen IV and laminin, the scaffold proteins of the basement membrane, and Dab2 in 50 ovarian tumors that are restricted to the ovaries and in 50 metastases of ovarian tumors by immunohistochemistry. Expression of collagen IV, laminin, and Dab2 was also analyzed by Northern blotting in a panel of human ovarian surface epithelial and cancer cell lines.

RESULTS

The basement membrane is often absent in morphologically benign ovarian surface and cyst epithelium and low-grade tumors and collagen IV and laminin are absent in the extracellular matrix of most of the primary tumors tested. Of the 50 ovarian tumors confined to the ovaries, 6% (3 of 50) were collagen IV positive and 24% (12 of 50) were laminin positive tumors. Of the 50 metastatic tumors, 16% (8 of 50) are collagen IV positive and 86% (43 of 50) are laminin positive. In addition, even in the metastatic ovarian tumors that are largely collagen IV negative, there are pockets of local areas in which the tumor cells are surrounded by collagen IV-positive staining. Dab2 is absent in the majority of ovarian tumors found in both ovaries and metastatic sites. In both nontumorigenic human ovarian surface epithelial and cancer cell lines, collagen IV, laminin, and Dab2 are expressed aberrantly.

CONCLUSIONS

Loss of the basement membrane may be an early event in the preneoplastic transformation of ovarian surface epithelium and in the early stages of tumorigenesis before tumor invasion and metastasis. The majority of primary ovarian tumors examined lack collagen IV and laminin in their extracellular matrix. However, expression of laminin is restored in the majority of metastatic tumors. Reexpression of collagen IV may also contribute to tumor metastasis. The ability of tumor cells to dynamically alter the expression of collagen IV and laminin may facilitate the shedding of cancer cells into the peritoneal spaces and subsequent attachment to the metastatic sites. We propose that loss of collagen IV and laminin may be an initial event in ovarian tumorigenicity and that restoration of collagen IV and laminin expression in the later stages of tumor development may promote metastasis of ovarian tumors.

Fuzzy decision analysis for integrated environmental vulnerability assessment of the mid-Atlantic Region

A fuzzy decision analysis method for integrating ecological indicators was developed. This was a combination of a fuzzy ranking method and the analytic hierarchy process (AHP). The method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, we were able to point out areas that were in relatively poor condition and/or vulnerable to future deterioration. The method offered an easy and comprehensive way to combine the strengths of fuzzy set theory and the AHP for ecological assessment. Furthermore, the suggested method can serve as a building block for the evaluation of environmental policies.

Molecular events associated with dysplastic morphologic transformation and initiation of ovarian tumorigenicity

BACKGROUND

Disabled-2 (Dab2), a candidate tumor suppressor of ovarian carcinoma, frequently (around 80%) loses its expression in ovarian tumors. Expression of exogenous Dab2 in tumor cell lines negatively regulates growth and suppresses the downstream signal of the Ras/mitogen activated protein kinase mitogenic pathway. The inactivation of Dab2 is believed to be an early event in ovarian tumorigenicity.

METHODS

The authors analyzed the correlation among expression of Dab2, presence of basement membrane (collagen IV and laminin), morphologic alteration of the surface epithelial cells, and expression of the mitotic index marker Mib-1 in 50 archived ovarian tumors by an immunohistochemical approach. The stainings of Dab2, Mib-1, collagen IV, and laminin in premalignant lesions bordering both normal and neoplastic ovarian surface epithelium from adjacent slides were analyzed in 50 ovarian tumors.

RESULTS

In these 50 ovarian tumors, the percentage of Mib-1 positive tumor cells distributed in a wide range, from 1% to 75%, and there has no strong correlation with the expression of Dab2. However, in the premalignant regions bordering tumor and normal ovarian surface epithelium, the loss of Dab2 expression closely correlated with the dysplastic morphologic transition and Mib-1 expression of the ovarian surface epithelial cells. In 20 foci in 12 out of the 50 tumors, a transition from normal to neoplastic morphology within a contiguous epithelium was observed, and in all cases the morphologic change correlated with the loss of Dab2 staining. In addition, the collagen and laminin staining of the basement membrane were absent or weakened in pre-malignant epithelium prior to loss of Dab2 expression in all these 20 cases. Nevertheless, collagen IV and laminin were detectable in established adenomas on the same tumor slides.

CONCLUSIONS

The loss of Dab2 is closely associated with the transition of ovarian surface epithelial cells to premalignant states and is likely involved in the initiation of ovarian tumorigenicity. Transient loss of collagen IV and laminin in the basement membrane of the premalignant epithelium and subsequent inactivation of Dab2 are common early events associated with tumorigenicity of the ovarian surface epithelium.

Disabled-2 mediates c-Fos suppression and the cell growth regulatory activity of retinoic acid in embryonic carcinoma cells

F9 embryonic stem cell-like teratocarcinoma cells are widely used to study early embryonic development and cell differentiation. The cells can be induced by retinoic acid to undergo endodermal differentiation. The retinoic acid-induced differentiation accompanies cell growth suppression, and thus, F9 cells are also often used as a model for analysis of retinoic acid biological activity. We have recently shown that MAPK activation and c-Fos expression are uncoupled in F9 cells upon retinoic acid-induced endodermal differentiation. The expression of the candidate tumor suppressor Disabled-2 is induced and correlates with cell growth suppression in F9 cells. We were not able to establish stable Disabled-2 expression by cDNA transfection in F9 cells without induction of spontaneous cell differentiation. Transient transfection of Dab2 by adenoviral vector nevertheless suppresses Elk-1 phosphorylation, c-Fos expression, and cell growth. In PA-1, another teratocarcinoma cell line of human origin that has no or very low levels of Disabled-2, retinoic acid fails to induce Disabled-2, correlating with a lack of growth suppression, although PA-1 is responsive to retinoic acid in morphological change. Transfection and expression of Disabled-2 in PA-1 cells mimic the effects of retinoic acid on growth suppression; the Disabled-2-expressing cells reach a much lower saturation density, and serum-stimulated c-Fos expression is greatly suppressed and disassociated from MAPK activation. Thus, Dab2 is one of the principal genes induced by retinoic acid involved in cell growth suppression, and expression of Dab2 alone is sufficient for uncoupling of MAPK activation and c-Fos expression. Resistance to retinoic acid regulation in PA-1 cells likely results from defects in retinoic acid up-regulation of Dab2 expression.

Ventricular interaction and external constraint account for decreased stroke work during volume loading in CHF

The slope of the stroke work (SW)-pulmonary capillary wedge pressure (PCWP) relation may be negative in congestive heart failure (CHF), implying decreased contractility based on the premise that PCWP is simply related to left ventricular (LV) end-diastolic volume. We hypothesized that the negative slope is explained by decreased transmural LV end-diastolic pressure (LVEDP), despite the increased LVEDP, and that contractility remains unchanged. Rapid pacing produced CHF in six dogs. Hemodynamic and dimension changes were then measured under anesthesia during volume manipulation. Volume loading increased pericardial pressure and LVEDP but decreased transmural LVEDP and SW. Right ventricular diameter increased and septum-to-LV free wall diameter decreased. Although the slopes of the SW-LVEDP relations were negative, the SW-transmural LVEDP relations remained positive, indicating unchanged contractility. Similarly, the SW-segment length relations suggested unchanged contractility. Pressure surrounding the LV must be subtracted from LVEDP to calculate transmural LVEDP accurately. When this was done in this model, the apparent decrease in contractility was no longer evident. Despite the increased LVEDP during volume loading, transmural LVEDP and therefore SW decreased and contractility remained unchanged.

An infectious transfer and expression system for genomic DNA loci in human and mouse cells

The recent completion of the human genome sequence allows genomics research to focus on understanding gene complexity, expression, and regulation. However, the routine-use genomic DNA expression systems required to investigate these phenomena are not well developed. Bacterial artificial chromosomes (BACs) and P1-based artificial chromosomes (PACs) have proved excellent tools for the human genome sequencing projects. We describe a system to rapidly and efficiently deliver and express BAC and PAC library clones in human and mouse cells by converting them into infectious amplicon vectors. We show packaging and intact delivery of genomic inserts of >100 kilobases with efficiencies of up to 100%. To demonstrate that genomic loci transferred in this way are functional, the complete human hypoxanthine phosphoribosyltransferase (HPRT) locus contained within a 115-kilobase BAC insert was shown to be expressed when delivered by infection into both a human HPRT-deficient fibroblast cell line and a mouse primary hepatocyte culture derived from Hprt-/- mice. Efficient gene delivery to primary cells is especially important, as these cells cannot be expanded using antibiotic selection. This work is the first demonstration of infectious delivery and expression of genomic DNA sequences of >100 kilobases, a technique that may prove useful for analyzing gene expression from the human genome.

Influence of insulin and testosterone on adrenocortical steroidogenesis in vitro: preliminary studies

OBJECTIVE

The mechanisms underlying the adrenal androgen (AA) excess of polycystic ovary syndrome (PCOS) remain unclear, although it is possible that the adrenocortical dysfunction may be a response to other, extraadrenal factors. Consistent with the pathophysiology of PCOS and with in vivo data in normal and PCOS women, we have hypothesized that insulin inhibits and that T stimulates AA secretion in vitro.

DESIGN

In vitro experimental study.

SETTING

University medical center.

PATIENT(S)

Normal human adrenals (n = 4 women, ages 25-57 years) were obtained with consent at the time of organ donation.

INTERVENTION(S)

Fresh adrenal tissue minces were incubated in serum-free medium with 10-microM pregnenolone substrate and 1-microM ACTH-(1-24). Challenge doses of 0.2, 1, 5, 20, and 100 nM of insulin and 1, 10, 100, 1,000, and 10,000 nM of T were added, and the media were sampled after 8 hours of incubation at 37 degrees C, 4% CO2. Dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEAS), and cortisol (F) were measured by radioimmunoassay (significant effects compared with the case of zero-dose control).

MAIN OUTCOME MEASURE(S)

The production of DHEA, DHEAS, and F in the media of the adrenal minces was compared between different subjects and at different concentrations of T and insulin.

RESULT(S)

Analysis of the combined data from all donors indicated that insulin stimulated DHEAS and suppressed DHEA production but had no consistent effect on F. Similar analyses of the combined data indicated that T had no significant predictable effect on the production of DHEAS, DHEA, or F. When examining donor data individually, insulin and T did elicit significant increases and/or decreases in steroid production within subjects, although no consistent trends were observed.

CONCLUSION(S)

On the basis of these data, it is clear that extra-adrenal factors such as insulin and T have some adrenal regulatory capacity. In general, insulin stimulated DHEAS and decreased DHEA production, suggesting that it increases adrenocortical sulfotransferase activity. However, although in the individual subjects studied, both insulin and T frequently altered the production of DHEAS, DHEA or F, these effects did not appear to be uniform or consistent from subject to subject. Expanded studies are required to confirm these results.

A diagnostic dilemma of fever and back pain postpartum

A 26-year-old woman presented with fever, chills, and back pain 6 weeks postpartum. An infused CT scan of the abdomen and pelvis with IV contrast confirmed septic pelvic vein thrombophlebitis as the diagnosis. To the best of our knowledge, this is the first case report describing such a massive thrombophlebitis extending from the superior vena cava to the femoral vein inferiorly responsive to conventional anticoagulation therapy. This exceptional case reminds us to entertain septic pelvic thrombophlebitis in the differential of any patient who presents with fever and back pain of unknown etiology.

Linking global histone acetylation to the transcription enhancement of X-chromosomal genes in Drosophila males

It has become well established for several genes that targeting of histone acetylation to promoters is required for the activation of transcription. In contrast, global patterns of acetylation have not been ascribed to any particular regulatory function. In Drosophila, a specific modification of H4, acetylation at lysine 16, is enriched at hundreds of sites on the male X chromosome due to the activity of the male-specific lethal (MSL) dosage compensation complex. Utilizing chromatin immunoprecipitation, we have determined that H4Ac16 is present along the entire length of X-linked genes targeted by the MSL complex with relatively modest levels of acetylation at the promoter regions and high levels in the middle and/or 3' end of the transcription units. We propose that global acetylation by the MSL complex increases the expression of X-linked genes by facilitating transcription elongation rather than by enhancing promoter accessibility. We have also determined that H4Ac16 is absent from a region of the X chromosome that includes a gene known to be dosage-compensated by a MSL-independent mechanism. This study represents the first biochemical interpretation of the very large body of cytological observations on the chromosomal distribution of the MSL complex.

Disassociation of MAPK activation and c-Fos expression in F9 embryonic carcinoma cells following retinoic acid-induced endoderm differentiation

Retinoic acid induces cell differentiation and suppresses cell growth in a wide spectrum of cell lines, and down-regulation of activator protein-1 activity by retinoic acid contributes to these effects. In embryonic stem cell-like F9 teratocarcinoma cells, which are widely used to study retinoic acid actions on gene regulation and early embryonic differentiation, retinoic acid treatment for 4 days resulted in suppression of cell growth and differentiation into primitive and then visceral endoderm-like cells, accompanied by a suppression of serum-induced c-Fos expression. The MAPK (ERK) pathway was involved in mitogenic signaling in F9 cells stimulated with serum. Surprisingly, although c-Fos expression was reduced, the MAPK activity was not decreased by retinoic acid treatment. We found that retinoic acid treatment inhibited the phosphorylation of Elk-1, a target of activated MAPK required for c-Fos transcription. In F9 cells, the MAPK/MEK inhibitor PD98059 suppressed Elk-1 phosphorylation and c-Fos expression, indicating that MAPK activity is required for Elk-1 phosphorylation/activation. Phosphoprotein phosphatase 2B (calcineurin), the major phosphatase for activated Elk-1, is not the target in the disassociation of MAPK activation and c-Fos expression since its inhibition by cyclosporin A or activation by ionomycin had no significant effects on serum-stimulated c-Fos expression and Elk-1 phosphorylation. Thus, we conclude that retinoic acid treatment to induce F9 cell differentiation uncouples Ras/MAPK activation from c-Fos expression by reduction of Elk-1 phosphorylation through a mechanism not involving the activation of phosphoprotein phosphatase 2B.