Biomedical subjects

E Lee

Publications and source records attributed to E Lee.

At least 127 records · Page 7Linked to original sources

PubMed2000

Intactness of zona pellucida does not affect the secretion of a trypsin-like protease from mouse blastocyst.

Assisted hatching (AH), which is known to improve the hatching potential of mammalian embryos, has been used to increase the pregnancy rate in in vitro fertilization cycles. However, the effect of AH on a trypsin-like protease, which is known to be associated with the hatching process, has not been studied. In this study, we evaluate whether the intactness of zona pellucida affects the secretion of a trypsin-like protease from mouse blastocyst. Four- to 8-cell stage mouse embryos were collected at 66- to 68 hr after hCG injection and divided into 3 groups according to the manipulation of zona pellucida. The groups are no treatment (control), drilling of zona pellucida (ZD) and thinning of zona pellucida (ZT). The activity of a trypsin-like protease, blastocyst development and hatching rate were compared among the three groups at 110 and 135 hr after hCG injection, respectively. The protease activity and blastocyst development were not significantly different among control, ZD and ZT groups at 110 and 135 hr after hCG injection, respectively. However, the hatching rate of ZD and ZT groups was significantly higher than that of control group at each time, respectively (p<0.001). Even in the zona pellucida removed embryos, the protease activity did not differ from the control group. In conclusion, the secretion of a trypsin-like protease from mouse blastocyst does not seem to be affected by the intactness of zona pellucida.

Animals↗

PubMed2000

Planning and simulation of neurosurgery in a virtual reality environment.

OBJECTIVE: To report our experience with preoperative neurosurgical planning in our stereoscopic virtual reality environment for 21 patients with intra- and extra-axial brain tumors and vascular malformations. METHODS: A neurosurgical planning system called VIVIAN (Virtual Intracranial Visualization and Navigation) was developed for the Dextroscope, a virtual reality environment in which the operator reaches with both hands behind a mirror into a computer-generated stereoscopic three-dimensional (3-D) object and moves and manipulates the object in real time with natural 3-D hand movements. Patient-specific data sets from multiple imaging techniques (magnetic resonance imaging, magnetic resonance angiography, magnetic resonance venography, and computed tomography) were coregistered, fused, and displayed as a stereoscopic 3-D object. A suite of 3-D tools accessible inside the VIVIAN workspace enabled users to coregister data, perform segmentation, obtain measurements, and simulate intraoperative viewpoints and the removal of bone and soft tissue. RESULTS: VIVIAN was used to plan neurosurgical procedures primarily in difficult-to-access areas, such as the cranial base and the deep brain. The intraoperative and virtual reality 3-D scenarios correlated well. The VIVIAN system substantially contributed to surgical planning by 1) providing a quick and better understanding of intracranial anatomic and abnormal spatial relationships, 2) simulating the craniotomy and the required cranial base bone work, and 3) simulating intraoperative views. CONCLUSION: The VIVIAN system allows users to work with complex imaging data in a fast, comprehensive, and intuitive manner. The 3-D interaction of this virtual reality environment is essential to the efficient assembly of surgically relevant spatial information from the data derived from multiple imaging techniques. The usefulness of the system is highly dependent on the accurate coregistration of the data and the real-time speed of the interaction.

Adult↗

PubMed2000

Home versus hospice inpatient care: discharge characteristics of palliative care patients in an acute care hospital.

This prospective survey was initiated to identify factors that helped and hindered home discharge for 100 consecutive patients who did not require further specialist palliative or acute care. Information was collected on demographics, functional ability (using the Palliative Performance Scale [PPS] and Karnofsky Performance Scale [KPS]), cognitive function at discharge as measured by the Mini-Mental State Examination (MMSE), home support circumstances, and patient and family preference for discharge. 59 patients were discharged home and 41 were transferred to a hospice. Younger patients with younger caregivers were discharged home more often. Patients with better MMSE and better functional ability (PPS and KPS) were also more likely to go home. Patients going home were more likely to be married. Preference for site of discharge was met for 76% of patients and 90% of families. Of the patients going to a hospice, 24% of patients and 7% of families preferred a home discharge. More physical support at home could have facilitated a home discharge for 13 patients. Functionally dependent and cognitively impaired patients were generally unable to return home. To support patients and their families in an environment of their choice, access to increased physical support in the home must be addressed.

Aged↗

PubMed1999

A receptor-based bioassay for quantitative detection of gallium.

The detection of gallium in biological samples is required due to its role in the diagnosis of tumor and for possible treatment of malignancies. However, the use of purely instrumental techniques is unsuitable for detection of low levels of gallium in biological matrixes. We have synthesized new protein conjugates based on 4-(2-pyridylazo) ligands. The conjugates were successfully employed for the detection of gallium in biological matrixes using a nonantibody-based sandwich assay format. The recovery level obtained was between 97 and 101.3 with a relative standard deviation of less than 5%. The assay resulted in a detection limit of 5 x 10(-8) M and a remarkable selectivity for gallium(III) relative to other metals investigated. The new method provided adequate accuracy for gallium applicable for animal physiology and clinical toxicology.

Biological Assay↗

PubMed1999

Arsenic disrupts cellular levels of p53 and mdm2: a potential mechanism of carcinogenesis.

The antitumor protein p53 plays a critical role in DNA repair. Inorganic arsenic exposure is associated with a wide variety of human tumors, particularly of the skin. To investigate how inorganic arsenic might interfere with DNA repair and lead to greater incidence of hyperkeratosis and skin tumors, we exposed human keratinocytes (HaCaT) to environmentally relevant concentrations of arsenite for 14 days. Arsenite reduced p53 levels while concomitantly increasing the p53 regulatory protein mdm2 levels in a dose- and time-dependent manner. We propose the disruption of the p53-mdm2 loop regulating cell cycle arrest as a model for arsenic-related skin carcinogenesis and it may be important in tumors with elevated mdm2 levels.

Arsenates↗

PubMed1999

In situ localization of neuronal nitric oxide synthase (nNOS) mRNA in the rat retina.

We performed a comparative study on the distribution of neuronal nitric oxide synthase (nNOS) immunoreactivity and mRNA in a normal rat retina using immunocytochemistry and in situ hybridization technique. As in previous studies, we found NOS immunoreactive (NOS-IR) cells and fibers in inner and outer plexiform layers (IPL and OPL), inner nuclear layer (INL) and inner photoreceptor segment (IPS). However, very little nNOS-IR could be detected in groups of amacrine cells and ganglion cells localized in ganglion cell layer (GCL). However, in situ hybridization showed that intense NOS mRNA signals were mainly found in the GCL and INL while weak or no mRNA signals were detected in IPL, OPL, outer nuclear layer (ONL) and IPS. This difference suggests that nNOS proteins may be transported through axons into the terminals in the IPL and OPL after they were synthesized with nNOS mRNA templates in the INL. In the case of nNOS mRNA in GCL, synthesizing nNOS proteins may move outside the eyeball and carry out tasks in central nervous system. The difference of nNOS mRNA and nNOS IR means that the complete concurrence of nNOS IR and in situ hybridization results may not always occur in the rat retina.

Animals↗

PubMed1999

In situ localization of p53, bcl-2 and bax mRNAs in rat ocular tissue.

We mapped p53, bcl-2 and bax mRNAs, which are known to have correlation with apoptotic cell death, in the rat ocular tissue. p53 mRNA signals were present in several layers of retina, optic nerve, corneal epithelium, ciliary process and posterior surface of the iris. While almost the same pattern as p53 was recognized in the case of bcl-2 mRNA, bax signals were not found in ocular tissue except for ganglion cell layer (GCL). These results suggest that in the normal ocular tissue, p53 and bcl-2 genes play opposing parts in the physiological control of cell survival and death. A p53 mediated tumor-suppressing action might occur through the induction of transcriptional targets other than bax because only in GCL were p53 and bax mRNA expression co-localized.

Animals↗

PubMed1999

Generation of human T-cell responses to an HLA-A2.1-restricted peptide epitope derived from alpha-fetoprotein.

Alpha-fetoprotein (AFP) is often derepressed in human hepatocellular carcinoma. Peptide fragments of AFP presented in the context of major histocompatibility molecules could serve as potential recognition targets by CD8 T cells, provided these lymphocytes were not clonally deleted in ontogeny. We therefore wished to determine whether the human T-cell repertoire could recognize AFP-derived peptide epitopes in the context of a common class I allele, HLA-A2.1. Dendritic cells genetically engineered to express AFP were capable of generating AFP-specific T-cell responses in autologous human lymphocyte cultures and in HLA-A2.1/Kb transgenic mice. These T cells recognize a 9-mer peptide derived from the AFP protein hAFP(542-550) (GVALQTMKQ). Identified as a potential A2.1-restricted peptide epitope from a computer analysis of the AFP sequence, hAFP(542-550) proved to have low binding affinity to A2.1, but slow off-kinetics. AFP-specific CTL- and IFN-gamma-producing cells recognize hAFP(542-550)-pulsed targets. Conversely, hAFP(542-550) peptide-generated T cells from both human lymphocyte cultures and A2.1/Kb transgenic mice recognized AFP-transfected targets in both cytotoxicity assays and cytokine release assays. These lines of evidence clearly demonstrate that AFP-reactive clones have not been deleted from the human T-cell repertoire and identify one immunodominant A2.1-restricted epitope. These findings also clearly establish AFP as a potential target for T-cell-based immunotherapy.

Amino Acid Sequence↗

PubMed1999

Resveratrol, an antioxidant present in red wine, induces apoptosis in human promyelocytic leukemia (HL-60) cells.

Resveratrol, a triphenolic stilbene present in grapes and other plants, has striking antioxidant and anti-inflammatory activities which have been considered to be responsible for the beneficial effects of red wine consumption on coronary heart disease. Recent studies reveal that resveratrol can inhibit each step of multistage carcinogenesis. However, the molecular mechanisms underlying anti-tumorigenic or chemopreventive activities of this phytochemical remain largely unknown. In the present work, we have found that resveratrol reduces viability and DNA synthesis capability of cultured human promyelocytic leukemia (HL-60) cells. The growth inhibitory and antiproliferative properties of resveratrol appear to be attributable to its induction of apoptotic cell death as determined by morphological and ultrastructural changes, internucleosomal DNA fragmentation, and increased proportion of the subdiploid cell population. Resveratrol treatment resulted in a gradual decrease in the expression of anti-apoptotic Bcl-2. These results, together with previous findings, suggest the cancer therapeutic as well as chemopreventive potential of resveratrol.

Anticarcinogenic Agents↗

PubMed1999

Control of hippocampal morphogenesis and neuronal differentiation by the LIM homeobox gene Lhx5.

The mammalian hippocampus contains the neural circuitry that is crucial for cognitive functions such as learning and memory. The development of such circuitry is dependent on the generation and correct placement of the appropriate number and types of neurons. Mice lacking function of the LIM homeobox gene Lhx5 showed a defect in hippocampus development. Hippocampal neural precursor cells were specified and proliferated, but many of them failed to either exit the cell cycle or to differentiate and migrate properly. Lhx5 is therefore essential for the regulation of precursor cell proliferation and the control of neuronal differentiation and migration during hippocampal development.

Animals↗

PubMed1999

Arsenic binding proteins from human lymphoblastoid cells.

Arsenic is a ubiquitous contaminant of drinking water and food. The mechanisms of the toxic action of inorganic arsenic are unknown. We report the isolation of proteins having a high affinity for arsenic in the +3 oxidation state that are induced by arsenite (AsIII) in human lymphoblastoid cells. The arsenic-binding proteins were isolated using a p-aminophenylarsine oxide affinity column. At least four proteins of 50, 42, 38.5 and 19.5 kDa were isolated by elution with 10 or 100 mM 2-mercaptoethanol. Two proteins were tentatively identified as tubulin and actin on the basis of their molecular weights and previously reported affinity for the arsenic column. The identities of the remaining proteins are unknown. Heme oxygenase 1 was induced by AsIII but did not bind to the arsenic affinity column. We conclude that AsIII induces multiple proteins that have variable affinities for arsenic in the +3 state as judged by the concentration of 2-mercaptoethanol required for their elution. The arsenic binding motif of these proteins may involve three thiol groups arranged 3-6 A apart by the tertiary structure of the protein as suggested by others. These proteins may serve as high affinity binding sites for AsIII and may be involved in the biological action of AsIII.

Actins↗

PubMed1999

Electrophoretic Mobility of a Concentrated Suspension of Spherical Particles.

The electrophoretic behavior of concentrated spherical colloidal particles is analyzed theoretically for all levels of scaled surface potential φa, taking the effect of double-layer polarization (DLP) into account. The result of numerical simulation reveals that for a very small kappaa (<0.01), kappa and a being, respectively, the reciprocal Debye length and the particle radius, or a very large kappaa (>100), using a linearized Poisson-Boltzmann equation (PBE) and neglecting the effect of DLP is reasonable; for an intermediate kappaa, appreciable deviation may result. The deviation is negative if kappaa is small, and positive if kappaa is large. The mobility against kappaa curve may have a local minimum and a local maximum. If φa is low, the mobility increases with the porosity of the system under consideration, and for a fixed porosity, the mobility increases with kappaa. If φa is high and kappaa is small, the effect of φa (i.e., solving a nonlinear PBE) on the mobility of a particle is more significant than that of double-layer polarization, and the reverse is true if kappaa is large. For an intermediate kappaa, the effect of DLP is more significant than that of φa when the porosity is high, and the reverse is true if it is low. Copyright 1999 Academic Press.

Journal Article↗

PubMed1999

Novel mutations in African American patients with glycogen storage disease Type II. Mutations in brief no. 209. Online.

The infantile form of GSD II (an inherited deficiency of the lysosomal enzyme, acid alpha-glucosidase, Pompe disease) is a severe and invariably fatal disease characterized by a rapidly progressive generalized hypotonia, hepatomegaly, and cardiomegaly. We have recently demonstrated that African American patients share a common nonsense R854X mutation in exon 18 (Becker et al., 1998). Two other mutations, D645E and M519V, have been identified in individual African American patients (Hermans et al., 1993a; Huie et al., 1994a). We describe here three novel mutations in this population group: a missense W481R in exon 10, a deletion of a T1441 in exon 10, and a splicing defect at the 5' donor site of intron 8 (IVS g+la) . The splicing defect is shared by two unrelated patients and it is linked to intragenic polymorphic sites identical to those found in patients bearing the common R854X mutation.

Amino Acid Substitution↗

PubMed1999

Costimulatory markers in muscle of patients with idiopathic inflammatory myopathies and in cultured muscle cells.

In an attempt to understand the mechanisms of cell injury in the inflammatory myopathies, we analyzed the expression of costimulatory molecules, CTLA4, CD28, CD86, CD40, and CD154 as well as HLA class I, HLA class II, and ICAM-I in normal muscle and in muscle biopsies from patients with polymyositis (PM) or dermatomyositis (DM). By immunohistochemical staining, DM and PM biopsies showed the presence of CTLA4, CD28, CD86, and CD40 on inflammatory cells. More strikingly, however, low levels of CTLA4 and CD28 were observed on muscle cells. The expression of CTLA4 and CD28 on nonlymphoid cells has not been previously reported. These unexpected findings were confirmed in cultured normal human myoblasts: various proinflammatory cytokines induced the expression of CTLA4 and CD28 on normal human muscle cells. The sequences of the cDNAs were found to be identical to the sequences for these molecules in T cells. The data suggest a novel complexity in the network of cellular interactions between the infiltrated immune cells and the muscle cells in which the normal relationship between infiltrating inflammatory cells and target tissue is under a previously unrecognized set of controls.

Abatacept↗

PubMed1999

Anti-allergic actions of the leaves of Castanea crenata and isolation of an active component responsible for the inhibition of mast cell degranulation.

The anti-allergic actions of the leaves of Castanea crenata (Fagaceae) were studied. The water extract demonstrated potent anti-allergic actions in in vivo and in vitro experiments. The oral or intraperitoneal administration of the extract (100 or 200 mg/kg) caused a significant inhibition of the 48 hr-PCA (up to 90%) and the vascular permeability induced by histamine or serotonin in rats (about 80%). The anaphylactic release of beta-hexosaminidase from RBL-2H3 cells was also significantly inhibited by the extract in a dose-dependent manner with an IC50 value of 230 microg/ml. The activity-guided fractionation of the extract, based on the determination of inhibitory effect upon the release of beta-hexosaminidase, led to the isolation of quercetin as an active principle responsible for the inhibition of degranulation.

Animals↗

PubMed1999

Growth retardation and neonatal lethality in mice with a homozygous deletion in the C-terminal domain of RNA polymerase II.

The C-terminal domain (CTD) of the largest subunit of RNA polymerase II consists of tandem repeats of the consensus heptapeptide YSPTSPS. Deletion studies in tissue culture cells have indicated that the CTD plays an essential role in transcription, although the nature of this essential function remains unclear. About half of the CTD can be deleted without affecting the viability of cells in tissue culture. Paradoxically, the dispensable CTD repeats are precisely conserved among all mammals whose CTD sequences are known. To determine whether the mammalian CTD is important in transcription during mouse development, we developed a gene targeting approach to introduce deletions into the CTD coding region of mouse embryonic stem (ES) cells. To maintain a functional Rpo2-1 gene, the neo marker in the targeting vector was positioned outside of the Rpo2-1 transcribed region, 1.2 kb from the site of the CTD deletion. G418-resistant clones were screened for co-integration of the CTD deletion, and the resulting ES lines were used to create germline chimeric mice. Stable heterozygous lines were established and mated to produce animals homozygous for the CTD deletion. We show here that mice homozygous for a deletion of thirteen of the 52 heptapeptide repeats are smaller than wild-type littermates and have a high rate of neonatal lethality. Surviving adults, although small, appear morphologically normal and are fertile. This result suggests that the CTD plays a role in regulating growth during mammalian development. The gene targeting approach described here should be useful for making further deletions in the CTD and may be of general applicability where it is desirable to engineer specific mutations in the germline of mice.

Amino Acid Sequence↗

PubMed1999

Inhaled and nasal corticosteroids: factors affecting the risks of systemic adverse effects.

There has been increasing concern in the medical literature about the safety of inhaled and nasal corticosteroids, since many patients, both adults and children, are increasingly prescribed these drugs for the long-term prophylactic treatment of asthma and rhinitis. It is well recognised that systemic absorption occurs following inhaled and nasal administration of corticosteroids, but the dose at which clinically relevant side effects occurs is controversial. The controversy stems from the fact that the degree of systemic absorption depends not only upon the prescribed dose, but also upon the mode of delivery and the severity of the underlying disease. From a regulatory view, it is essential that the Product Information (Summary of Product Characteristics and Patient Information Leaflet) reflects the available evidence to enable a doctor to make an informed decision when prescribing these medicines. This article assesses the potential for inhaled and nasal corticosteroids to cause systemic adverse effects by analysing the published literature and spontaneously reported suspected adverse drug reactions reported to the Committee on Safety of Medicines and Medicines Control Agency. Five main areas of concern were reviewed: hypothalamic-pituitary-adrenal axis suppression, osteoporosis or changes in bone mineral density, growth retardation in children, cataracts, and glaucoma. Conclusions regarding these side effects at licensed doses of inhaled and nasal corticosteroids are reached and the clinical relevance is discussed, particularly following long-term therapy. The recommendations of the Committee on Safety of Medicines and Medicines Control Agency are included.

Administration, Inhalation↗

PubMed1999

Injury surveillance in a pediatric emergency department.

In this study we have tried to determine physician success in the collection of injury data during the emergency department visit. Prospective data were collected from all children between the ages of 0 to 18 treated for an injury. Data were collected at the time of the visit and by chart review the next day. At an urban, university-affiliated, children's hospital, data were collected on 2,156 injured children. Fifty-one percent of the data forms were completed by the treating physician. Physician completion rate was lower on the weekends (46%) than on weekdays (52%, P = .02). The most common mechanisms of injury were falls (34%), motor-vehicle crashes or pedestrians struck (13%), and nonintentional struck by blunt object (12%). The most common mechanism of injury in all age groups was falls. Our results demonstrate that emergency physicians are not successful data collectors. However, when physician data collection is combined with next-day review of patient records, virtually 100% of patients are captured. Active emergency department data collection is important because in contrast to studies which use hospital discharge and mortality data, we found that overall falls account for more injuries presenting to the ED than transportation-related causes. An active surveillance system in emergency departments that does not require extra work on the part of the treating physician would be ideal and may give a more comprehensive description of the scope of the injury problem.

Adolescent↗