Effect of antioxidant protection by p-coumaric acid on low-density lipoprotein cholesterol oxidation

Mechanisms in which p-coumaric acid (CA) acts as an antioxidant are not well understood. This study investigated whether CA can act as a direct scavenger of reactive oxygen species (ROS) and whether it minimizes the oxidation of low-density lipoprotein (LDL). Rats were administered CA in drinking water at low or high doses for 10, 21, and 30 days (uptakes were 29 and 317 mg/day, respectively). Blood levels of 8-epiprostaglandin F(2alpha) were monitored as a marker of LDL oxidation. Oral administration of CA (317 mg/day) for 30 days significantly inhibited LDL oxidation. CA also reduced LDL cholesterol levels in serum but had no effect on levels of high-density lipoprotein cholesterol. In vitro studies that used electron spin resonance in combination with spin trapping techniques were used to determine the ability of CA to scavenge ROS and alter LDL oxidation. CA effectively scavenged.OH in a dose-dependent manner. IC(50) and maximum velocity for CA scavenging of.OH were 4. 72 microM and 1.2 microM/s, respectively, with a rate constant of 1. 8 x 10(11) M(-1). s(-1). Our studies suggest that the antioxidant properties of CA may involve the direct scavenging of ROS such as.OH.

Modes of regulation of laminin-5 production by rat astrocytes

Astrocytes have a prominent role in central nervous system-specific microvascular growth and function. Extracellular matrix molecules (ECMs) bind to specific adhesion molecules - integrins. These adhesion complexes are responsible for tissue integrity and cellular signalling. We have examined astrocyte-endothelial cell interactions in relation to expression of the ECM laminin-5. Astrocytes produce laminin-5 in cell culture. The production is enhanced by endothelial cells. Direct cellular contact possibly involving a beta1 integrin or an insoluble matrix compound detected by the astrocytes is responsible for the induction of astrocytic laminin production by endothelial cells. Hypoxia also influences ECM production. The described regulation goes in concert with the known effects of astrocyte-endothelial cell interaction and stresses its importance for microvascular integrity.

Reduced gut intraepithelial lymphocytes in VLA1 null mice

Very late antigen 1 (VLA1) is an integrin collagen receptor that is expressed by lymphocytes in several disease states. VLA1 blockade has been shown to ameliorate gut disease in experimental graft-versus-host disease. Here we show that in the VLA1 null mouse, which is generally healthy, there is a 50% reduction in gut intraepithelial lymphocytes (IELs) despite an otherwise normal lymphocyte distribution in peripheral blood and lymphoid organs. The gammadelta to alphabeta ratios of IELs are unchanged. We also find that IL2-stimulated splenocytes from VLA1 null animals show a deficiency in adhesion to fibrillar and basement membrane collagen as well as reduced proliferation in response to collagen substratum. These results suggest that some, but not all, intraepithelial lymphocytes require VLA1 to survive or proliferate within the gut epithelium or possibly to traverse the basement membrane.

Regulation of inflammation by collagen-binding integrins alpha1beta1 and alpha2beta1 in models of hypersensitivity and arthritis

Adhesive interactions play an important role in inflammation by promoting leukocyte attachment and extravasation from the vasculature into the peripheral tissues. However, the importance of adhesion molecules within the extracellular matrix-rich environment of peripheral tissues, in which cells must migrate and be activated, has not been well explored. We investigated the role of the major collagen-binding integrins, alpha1beta1 and alpha2beta1, in several in vivo models of inflammation. mAb's against murine alpha1 and alpha2 were found to significantly inhibit effector phase inflammatory responses in animal models of delayed-type hypersensitivity (DTH), contact hypersensitivity (CHS), and arthritis. Mice that were alpha1-deficient also showed decreased inflammatory responses in the CHS and arthritis models when compared with wild-type mice. Decreased leukocyte infiltration and edema formation accompanied inhibition of antigen-specific models of inflammation, as nonspecific inflammation induced by croton oil was not inhibited. This study demonstrates the importance in vivo of alpha1beta1 and alpha2beta1, the collagen-binding integrins, in inflammatory diseases. The study also extends the role of integrins in inflammation beyond leukocyte attachment and extravasation at the vascular endothelial interface, revealing the extracellular matrix environment of peripheral tissues as a new point of intervention for adhesion-based therapies.

Strategies for assessing the implications of malformed frogs for environmental health

The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state level. Discussions highlighted possible causes and recent findings directly related to frog deformities and provided insight into problems and strategies applicable to continuing investigation in several areas. Possible causes of the deformities were evaluated in terms of diagnostics performed on field amphibians, biologic mechanisms that can lead to the types of malformations observed, and parallel laboratory and field studies. Hydrogeochemistry must be more integrated into environmental toxicology because of the pivotal role of the aquatic environment and the importance of fates and transport relative to any potential exposure. There is no indication of whether there may be a human health factor associated with the deformities. However, the possibility that causal agents may be waterborne indicates a need to identify the relevant factors and establish the relationship between environmental and human health in terms of hazard assessment.

Scavenging of superoxide anion radical by chaparral

Chaparral is considered to act as an antioxidant. However, the inhibitory effects of chaparral on specific radical species are not well understood. Using electron paramagnetic resonance (EPR) spectroscopy in combination with spin trapping techniques, we have found that chaparral scavenges superoxide anion radical (O2*-) in a dose-dependent manner. 5,5-dimethyl-lpyrroline-N-oxide (DMPO) was used as a spin trapping agent and the reaction of xanthine and xanthine oxidase as a source of O2*-. The kinetic parameters, IC50 and Vmax, for chaparral scavenging of O2*- were found to be 0.899 microg/mL and 8.4 ng/mL/sec, respectively. The rate constant for chaparral scavenging O2*- was found to be 1.22 x 10(6) g(-1) s(-1). Our studies suggest that the antioxidant properties of chaparral may involve a direct scavenging effect of the primary oxygen radical, O2*-.

Transplantation of related and unrelated umbilical cord blood stem cells in Austria. Austrian Working Party for Stem Cell Transplantation. Austrian Society of Hematology and Oncology

Allogeneic bone marrow transplantation is limited by the availability of suitable HLA-matched donors and the risk of graft versus host disease (GvHD). In an attempt to overcome these limitations umbilical cord blood (UCB), has become a further alternative. UCB transplantations in Austria were started in 1991. As of September 31, 1998, six patients have been transplanted. Diagnoses were severe aplastic anaemia (SAA) (n = 2), acute lymphoblastic leukaemia (ALL) (n = 1), familial hemophagocytic syndrome (FHL) (n = 2) and chronic myelomonocytic leukaemia (CMML) (n = 1). Three patients received UCB grafts from HLA-identical siblings and three patients from unrelated donors, of whom two were disparate at two HLA loci (A/B) and one mismatched at one locus (C). Five patients were engrafted with complete donor hematopoiesis, with a median time of 26.5 days (range 14 to 39 days) to an ANC count of > or = 0.5 x 10(9)/L and a median time of 42.5 days (range 24 to 67 days) to a platelet count of > or = 20 x 10(9)/L. One patient with FHL had partial engraftment and died due to reactivation of cytomegalovirus (CMV) infection and CMV pneumonia on day +25. Of the five patients surviving the post-transplant period, one with CMML had a relapse on day +128 and died after a HLA-matched bone marrow transplantation from the same sibling donor in the second relapse. Another patient with ALL relapsed on day +200 but is still alive under palliative treatment; one patient with SAA showed graft rejection and autologous hematopoietic reconstitution and later had a successful CD34(+)-selected allogeneic peripheral stem cell transplant from a C-locus mismatched unrelated donor. Two patients (one with SAA and one with FHL) are alive with complete remission of the underlying disease. This report reflects the experience and results of UCB transplantation in Austria and discusses the position of UCB transplantation in the context of the other stem cell alternatives available today.

Mammalian immunoassays for predicting the toxicity of malathion in a laboratory fish model

This study describes the use of a panel of immune assays, originally developed by the National Toxicology Program for assessing xenobiotic-induced immunotoxicity in mice, to quantify the effects of sublethal malathion exposure on the immune responses of fish. For this study, Japanese medaka (Oryzias latipes) were exposed subchronically to the organophosphate pesticide malathion in a series of two experiments. In the first set of studies, fish were exposed for 7 or 14 d to untreated well water (i.e., controls) or to waterborne malathion at 0.2 or 0.8 mg/L. Following exposure, fish from each group were sacrificed and their kidneys (primary organ of leukopoiesis in fish and equivalent to mammalian bone marrow) were used to provide cells for assessing any malathion-induced effects upon nonspecific and acquired immune defense mechanisms. Effects upon humoral-mediated immunity were determined by enumerating antibody plaque-forming cell (PFC) numbers from a subset of fish exposed to malathion for 14 d and then injected intraperitoneally (ip) with sheep erythrocytes (sRBC). Results of these studies demonstrated that while malathion exposure had no significant effect upon hematocrit/leukocrit values or upon mitogen-stimulated T-cell lymphoproliferation, PFC numbers in the kidney of exposed fish were significantly reduced (compared to control fish) in a dose-dependent manner. In addition, total recoverable kidney cell numbers and viability, as well as superoxide anion production by kidney phagocytes, were reduced slightly (compared to control values) in fish exposed for 14 d to the highest malathion concentration tested. In the second set of experiments, medaka exposed for up to 21 d to either 0.1 or 0.3 mg malathion/L were challenged ip with an LD50 dose of the bacterial fish pathogen Yersinia ruckeri. Results from these infectivity studies demonstrated that exposure to either malathion concentration, for 14 or 21 d reduced host resistance against Yersinia infection. Taken together, these findings demonstrate the applicability of mammalian immune assays for predicting malathion-induced immunosuppression in a teleost fish, as well as the potential utility of a small laboratory fish to serve as an alternate model for mammals in immunotoxicological studies.

Absence of integrin alpha1beta1 in the mouse causes loss of feedback regulation of collagen synthesis in normal and wounded dermis

Integrin alpha1beta1 is a collagen receptor predominantly found in mesenchymal tissues. Mice lacking this receptor are viable. We have previously suggested that alpha1beta1 might participate in the down-regulation of collagen gene expression observed in cells suspended inside collagen gels. The results presented here demonstrate that integrin alpha1beta1 acts as a feedback regulator of collagen synthesis both in vitro and in vivo. Firstly, alpha1 null animals show a higher rate of collagen synthesis in the dermis in vivo. Secondly, fibroblasts derived from alpha1 null cutaneous wounds show a reduced sensitivity to collagen gel induced downregulation of collagen mRNA synthesis, as compared to their wild-type counterparts. An increase in collagenase synthesis is also seen in the alpha1 null dermis and in collagen gel suspended fibroblasts. While dermal thickness is normal in the alpha1 null animals, an increase is seen in skin thickness of alpha1 null but not alpha1 heterozygote animals on a background of collagenase resistant collagen. Increased expression of both collagen and collagenase mRNA are seen in experimental granulation tissue in alpha1 null animals, but their ultimate accumulation of collagen is normal, probably due to non alpha1 dependent paracrine regulators of collagen turnover.

Scavenging of reactive oxygen species by melatonin

The direct effects of the neurohormone melatonin on reactive oxygen species (ROS) were investigated. Melatonin was found to inhibit DMPO-O-2 formation in a dose-dependent manner. At the level of 1. 7+/-0.07 mM, melatonin caused 50% inhibition of EPR signal intensity of DMPO-O-2 during the reaction of xanthine and xanthine oxidase. The reaction rate constant of melatonin with O2- was found to be 1.25+/-0.07x103 M-1 s-1. However, melatonin (up to 1.2 mM) did not exhibit significant effect toward OH radical, produced by the Fenton reaction. In addition, we found no evidence for the formation of the melatonin indolyl cation radical that presumably precedes conversion of melatonin to its stable N1-acetyl-N2-5-methoxykynuramine (AMK) metabolite following sequential reactions of melatonin with O2- and OH. On the other hand, melatonin was capable of scavenging H2O2 in a dose-dependent manner with an IC50=0.5+/-0.02 mM. The reaction rate constant of melatonin with H2O2 was found to be 2.52+/-0.19x105 M-1 s-1. Furthermore, melatonin was also found to inhibit 1O2-dependent 2,2,6,6-tetramethylpiperidine oxide (TEMPO) radical formation during rose bengal photodynamic reaction. The results suggest that melatonin's antioxidant properties, in part, may involve a direct effect on scavenging of ROS.

The concept of family: perceptions of adults who were in long-term out-of-home care as children

The author presents findings from a study in which adults fostered as children identified current family members. Those who included biological parents among their family members reported conflicted relationships, but also spoke of love. In contrast, those who omitted their biological parents seemed angrier, were more likely to have been abused, and were visited less by their biological parents. Those who included their foster parents described feeling loved, said they were not discriminated against, and received ongoing support after leaving care. Those who omitted members of their foster families overwhelmingly described feeling unloved and uncared for; said they were abused, devalued, and discriminated against; and received no continuing support.

Smad6 functions as an intracellular antagonist of some TGF-beta family members during Xenopus embryogenesis

BACKGROUND

Bone morphogenetic proteins (BMPs) transmit signals via the intracellular protein Smad1, which is phosphorylated by ligand bound receptors, translocates to the nucleus, and functions to activate BMP target genes. Recently, a subclass of Smad proteins has been shown to inhibit, rather than transduce, BMP signalling, either by binding to the intracellular domain of BMP receptors, thereby preventing phosphorylation-mediated activation of Smad1, or by binding directly to Smad1, thereby inhibiting its ability to activate gene transcription.

RESULTS

We have identified a Xenopus Smad (Smad6) that is 52% identical to mammalian Smad6, an inhibitory Smad. The spatial pattern of expression of Smad6 changes dynamically during embryogenesis and is similar to that of BMP-4 at the tailbud stage. Overexpression of Smad6 in Xenopus embryos phenocopies the effect of blocking BMP-4 signalling, leading to dorsalization of mesoderm and neuralization of ectoderm. Xenopus Smad6 completely blocks the activity of exogenous BMP-4, and, unlike human Smad6, partially blocks the activity of activin, in a mesoderm induction assay. We also find that Smad6 protein accumulates at the membrane in some cells but is partially or completely restricted to nuclei of most overexpressing cells.

CONCLUSIONS

We have identified an inhibitory Xenopus Smad, Smad6, that functions as an intracellular antagonist of activin and BMP-4 signalling. Our finding that Smad6 protein is partially or completely restricted to nuclei of most overexpressing cells suggests that it may employ a novel or additional mechanism of action to antagonize TGF-beta family signalling other than that reported for other inhibitory Smads.

Zfx mutation results in small animal size and reduced germ cell number in male and female mice

The zinc-finger proteins ZFX and ZFY, encoded by genes on the mammalian X and Y chromosomes, have been speculated to function in sex differentiation, spermatogenesis, and Turner syndrome. We derived Zfx mutant mice by targeted mutagenesis. Mutant mice (both males and females) were smaller, less viable, and had fewer germ cells than wild-type mice, features also found in human females with an XO karyotype (Turner syndrome). Mutant XY animals were fully masculinized, with testes and male genitalia, and were fertile, but sperm counts were reduced by one half. Homozygous mutant XX animals were fully feminized, with ovaries and female genitalia, but showed a shortage of oocytes resulting in diminished fertility and shortened reproductive lifespan, as in premature ovarian failure in humans. The number of primordial germ cells was reduced in both XX and XY mutant animals at embryonic day 11.5, prior to gonadal sex differentiation. Zfx mutant animals exhibited a growth deficit evident at embryonic day 12.5, which persisted throughout postnatal life and was not complemented by the Zfy genes. These phenotypes provide the first direct evidence for a role of Zfx in growth and reproductive development.

HMOs, moral hazard and cost shifting in workers' compensation

Previous research has shown that workers respond to the economic incentives provided in workers' compensation. In particular, claim frequency rises with increased benefits, and claim duration, on net, seems to increase. Here we provide additional evidence of another incidence of behavioral responses to incentives. We find that doctors in health maintenance organizations (HMOs) have a greater tendency to classify claims as compensable under workers' compensation than do other physicians. Our evidence suggests that the rapid expansion of HMOs over the 1980-1990 period resulted in a significant increase in workers' compensation claim frequency.

Autologous stem cell transplantation for solid tumors in children

The dose-effect relationship in pediatric oncology conventional chemotherapy is emphasized. Rationales for the use of megatherapy protocols with stem cell support and associated procedures are given. It has been more than 15 years since this approach was used in neuroblastoma, and it has subsequently been applied to most of advanced, common childhood solid tumors. The ongoing use of new strategies for dose intensification with peripheral blood stem cell or autologous purged bone marrow rescue has raised expectations for cure. To date, results of megatherapy followed by autologous stem cell reinfusion are encouraging in metastatic neuroblastoma and Ewing's sarcoma, with an increase in event-free survival rates of about 30% as compared with that of conventional treatments. However, with the exception of metastatic neuroblastoma, there is still no proven role for this treatment strategy. Thus, there is still an urgent need for international collaboration to design randomized studies that could rapidly address the issue of these expensive and high-morbidity procedures in childhood cancer.

Are your minimal pairs too neat? The dangers of phonemicisation in phonology therapy

Using Conversation Analysis (CA) to look at the interactional dynamics of therapy repair sequences, this paper shows exactly what happens for children when idealised misrepresentations of their phonology are used in therapy. The primary video extract involves a 4-year-old phonologically disordered boy and his therapist. It is not new to warn of the dangers of overlooking any subtle phonetic distinctions that the phonologically disordered child may have but this paper adds something new to the debate. The child's interpretation of the adult's prior turn in the sequence is made explicit and the likelihood of the child producing phonetic revision following an error is seen to be affected by the way the therapist chooses to initiate repair. This is especially true where a 'redoing' of the error is incorporated into such an initiation, when the child's phonetic output is 'tidied up' so that it fits in with the neat minimal pair which forms part of the therapy programme. This is one factor that can be seen to militate against appropriate phonetic repair by the child, especially when used in certain turn structures that are routinely associated with lexical rather than phonetic matters. When the adult 'redoing' more accurately reflects the child's output phonetic revision is more likely to occur. Implications for assessment and therapy are drawn from this evidence, with accurate phonological assessment and continuing interactional error analysis being recommended.

Cyclin D2 is an FSH-responsive gene involved in gonadal cell proliferation and oncogenesis

THE D-type cyclins (D1, D2 and D3) are critical governors of the cell-cycle clock apparatus during the G1 phase of the mammalian cell cycle. These three D-type cyclins are expressed in overlapping, apparently redundant fashion in the proliferating tissues. To investigate why mammalian cells need three distinct D-type cyclins, we have generated mice bearing a disrupted cyclin D2 gene by using gene targeting in embryonic stem cells. Cyclin D2-deficient females are sterile owing to the inability of ovarian granulosa cells to proliferate normally in response to follicle-stimulating hormone (FSH), whereas mutant males display hypoplastic testes. In ovarian granulosa cells, cyclin D2 is specifically induced by FSH via a cyclic-AMP-dependent pathway, indicating that expression of the various D-type cyclins is under control of distinct intracellular signalling pathways. The hypoplasia seen in cyclin D2(-/-) ovaries and testes prompted us to examine human cancers deriving from corresponding tissues. We find that some human ovarian and testicular tumours contain high levels of cyclin D2 messenger RNA.

Deletion of integrin alpha 1 by homologous recombination permits normal murine development but gives rise to a specific deficit in cell adhesion

Integrin alpha 1 is a receptor for laminin and collagen which is expressed widely and dynamically in embryogenesis and has been implicated in various developmental processes including establishment of the placenta and formation of the central and peripheral nervous system. In the adult it is the sole collagen receptor in smooth muscle and liver and is thought to be important for the stability of these tissues. We have generated a null allele of the alpha 1 gene in the germline of mice by homologous recombination in embryonic stem cells. Mice homozygous for the mutation are viable and fertile and have no overt phenotype, demonstrating that the molecule is not required for development. Embryonic fibroblasts derived from mutant animals are unable to spread on or migrate into substrata of collagen IV and are deficient in spreading on and migrating into laminin. Further in vitro analysis of cell spreading and migration suggests that alpha 1 beta 1 is not required for binding to collagen I and implicates a third receptor, possibly integrin alpha 3 beta 1, in collagen I binding.

The concept of family: perceptions of children in family foster care

Forty-three children in family foster care and 42 matched controls completed the Kvebaek Family Sculpture Technique, choosing figures to represent family members and placing these on a board to indicate how close they felt to each. Each child's ideal family representation was also obtained. The children in care consistently related to their foster family, rather than their biological kin, as "family." There was no evidence that these children in care preferred to live with their biological family. These findings are limited to children in long-term care, and may be further restricted because the family foster care sample consisted of children aged eight to 15 who had no disabilities. Nevertheless, the results have implications for family foster care policy.

Cyclin D1 provides a link between development and oncogenesis in the retina and breast

Mice lacking cyclin D1 have been generated by gene targeting in embryonic stem cells. Cyclin D1-deficient animals develop to term but show reduced body size, reduced viability, and symptoms of neurological impairment. Their retinas display a striking reduction in cell number due to proliferative failure during embryonic development. In situ hybridization studies of normal mouse embryos revealed an extremely high level of cyclin D1 in the retina, suggesting a special dependence of this tissue on cyclin D1. In adult mutant females, the breast epithelial compartment fails to undergo the massive proliferative changes associated with pregnancy despite normal levels of ovarian steroid hormones. Thus, steroid-induced proliferation of mammary epithelium during pregnancy may be driven through cyclin D1.

The effect of testicular nongerm cell tumors on local spermatogenesis

OBJECTIVE

To assess ipsilateral spermatogenesis in men with malignant and benign nongerm cell tumors of the testis.

DESIGN, PATIENTS

Histologic review of radical orchiectomy specimens performed for 20 men with malignant nongerm cell tumors and 15 with benign testicular lesions, including five Leydig cell tumors with benign clinical features.

MAIN OUTCOME MEASURES

Degree of spermatogenesis was determined on a 1 to 10 scale, with 10 representing mature sperm within a seminiferous tubule. For each patient "near" and "far" scores were determined by obtaining the mean score of 50 tubules adjacent (< 3 mm) to the tumor and 50 tubules distant (> 3 mm) from the tumor, respectively.

RESULTS

Total, near, and far scores were all lower for malignant tumors than for benign lesions. Scores for Leydig cell tumors were similar to benign lesions. Malignant tumors demonstrated a gradient effect, with greatest impairment of spermatogenesis occurring adjacent to tumor. In contrast, a distinction between near and far scores was not observed for benign lesions or Leydig cell tumors.

CONCLUSIONS

Malignant nongerm cell tumors of the testis were associated with significant impairment of ipsilateral spermatogenesis, particularly in areas adjacent to tumor. These findings are similar to those observed for testicular germ cell tumors, suggesting a generalized negative influence on ipsilateral spermatogenesis by malignant tumors.

Influence of testicular carcinoma on ipsilateral spermatogenesis

A histological review of radical orchiectomy specimens was performed to assess the impact of testicular cancer on spermatogenesis. Slides from 28 patients with testicular cancer were available for review, consisting of 14 pure seminomas, 12 embryonal carcinomas and 2 mixed tumors. For each specimen tubules adjacent (less than 3 mm.) to the tumor and distant (more than 3 mm.) from the tumor were evaluated. This study indicates that marked impairment of ipsilateral spermatogenesis is associated with testicular carcinoma, particularly in the vicinity of the tumor. The quality of distant spermatogenesis appears to be influenced by tumor type and not by elevation of known serum tumor markers, such as human chorionic gonadotropin and alpha-fetoprotein, nor by the presence of carcinoma in situ.