First trimester prenatal diagnosis of trisomy 21 in fetal cells from maternal blood.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
J Price
Publications and source records attributed to J Price.
The dispersion of neuronal clones across the cerebral cortex.
Explore the source record for details and available documents.
Animals↗
Myosin light chain-2 luciferase transgenic mice reveal distinct regulatory programs for cardiac and skeletal muscle-specific expression of a single contractile protein gene.
To examine the relationship between the cardiac and skeletal muscle gene programs, the current study employs the regulatory (phosphorylatable) myosin light chain (MLC-2) as a model system. Northern blotting, primer extension, and RNase protection studies documented the high level expression of the cardiac MLC-2 mRNA in both mouse cardiac and slow skeletal muscle (soleus). Transgenic mouse lines harboring a 2100- or a 250-base pair rat cardiac MLC-2 promoter/luciferase fusion gene were generated, demonstrating high levels of luciferase activity in cardiac muscle, and only background luminescence in slow skeletal muscle and non-muscle tissues. As assessed by in situ hybridization, immunofluorescence, and luminescence assays of luciferase reporter activity in various regions of the heart, both the endogenous MLC-2 gene and the MLC-2 luciferase fusion gene were expressed exclusively in the ventricular compartment, with expression in the atrium at background levels. Point mutations within the conserved regulatory sites HF-1a and HF-1b significantly cripple ventricular muscle specificity, while mutation of the single E-box site was without effect, suggesting that ventricular muscle-specific expression occurs through an E-box-independent pathway. This study provides direct evidence that the cis regulatory sequences in the cardiac/slow twitch MLC-2 gene which confer cardiac and skeletal muscle-specific expression can be clearly segregated, suggesting that distinct regulatory programs may have evolved to control the tissue-specific expression of this single contractile protein gene in cardiac and skeletal muscle.
Amino Acid Sequence↗
Ontogeny of a biological clock in Drosophila melanogaster.
Drosophila melanogaster born and reared in constant darkness exhibit circadian locomotor activity rhythms as adults. However, the rhythms of the individual flies composing these populations are not synchronized with one another. This lack of synchrony is evident in populations of flies commencing development at the same time, indicating that a biological clock controlling circadian rhythmicity in Drosophila begins to function without a requirement for light and without a developmentally imparted phase. It is possible to synchronize the phases of rhythms produced by dark-reared flies with light treatments ending as early as the developmental transition from embryo to first-instar larva: Light treatments occurring at developmental times preceding hatching of the first-instar larva fail to synchronize adult locomotor activity rhythms, while treatments ending at completion of larval hatching entrain these rhythms. The synchronized rhythmic behavior of adult flies receiving such light treatments suggests that a clock controlling circadian rhythms may function continuously from the time of larval hatching to adulthood.
Age Factors↗
What have tissue culture studies told us about the development of oligodendrocytes?
One major success of studying neural cell development in tissue culture has been the discovery of the O-2A cell. This bipotential cell generates oligodendrocytes or, under certain conditions, a type of astrocyte. This essay considers the evidence that the characteristic properties demonstrated by the O-2A cells in vitro are an accurate reflection of oligodendrocyte development in vivo.
Animals↗
The distribution of clones of neurons in the rat somatosensory cortex.
We have labelled clones of neurons in the cerebral cortex of rats by introducing a retroviral vector, called BAG, into the cerebral vesicles of embryos in utero. BAG encodes the enzyme beta-galactosidase, which acts as a histochemical marker for the subsequent identification of clones derived from infected precursor cells. We have studied the distribution of neuronal clones in the rat somatosensory cortex, and have asked whether clonally-related neurons were dispersed randomly. We have discovered that they are not. Rather, clones disperse predominantly such that the earliest progeny of ventricular zone cell are found posterolateral to later generated cells. This distribution fits with what would be expected were neurons dispersed passively in accordance with the lateral to medial cortical neurogenic gradient.
Aging↗
Neuronal precursor cells in the rat hippocampal formation contribute to more than one cytoarchitectonic area.
We have tested the hypothesis that cell lineage restriction boundaries define the borders between cytoarchitectonic areas in the cerebral cortex. Clonally related cells were identified using a retroviral marking technique, and the dispersion of neuronal clones was examined with respect to the transitions between cortical areas. We chose to study the hippocampal formation because we found that clones of hippocampal neurons, unlike those in neocortex, are compact and readily identifiable in the adult and that transitions between areas in the hippocampus are sharp relative to the spread of a typical clone. We conclude, contrary to the hypothesis, that clones of neurons transgress the boundaries between areas in the hippocampal formation, that border-crossing clones are observed as frequently as would be expected if clones spread freely over the hippocampus with no constraint imposed by area borders, and that different types of pyramidal neurons, characteristic of different areas, may appear to a single clone. different areas, may appear in a single clone.
Animals↗
Raising awareness about reproductive morbidity.
Lack of awareness of the extent and effect of reproductive morbidity on the health and quality of life of women in developing countries is evident at national, community and individual levels. Raising awareness at national level requires population-based, epidemiological information which must be validated. At community level, public opinion mediates women's actions when they are sick and fear of social consequences provides a barrier to treatment. Individually, women find it difficult to talk about sexual reproductive health and its management. Methodologies currently being developed for raising awareness at all levels are described.
Awareness↗
CT appearances of rounded atelectasis.
Five patients examined with CT had lesions fulfilling criteria for a diagnosis of rounded atelectasis (RA) and these were managed without biopsy. In three patients unsuspected contralateral lesions were identified as RA variants, and one of these was biopsied at thoracotomy and proved to be benign. All patients remain well at 6-22 months follow-up. We concur with recent reports that there is a spectrum of CT appearances of RA and that even atypical lesions seldom need further investigation. We also suggest that the appearances of some atypical lesions add support for the fibrosing theory of pathogenesis of RA.
Aged↗
A review of the morphology of human nasal mast cells as studied by light and electron microscopy.
This review discusses the distribution and classification of human nasal mast cells after the use of different fixatives, and some of their staining characteristics, both at the light- and electron-microscopical level. The problems encountered with alcoholic and formaldehyde fixation are discussed as well as the limitations of different stains (including the basic aniline dyes), esterase cytochemistry and immunological techniques. Also, the respective limitations of light and electron microscopy are compared. Cells studied by means of electron microscopy are much more difficult to quantify objectively. It is concluded that classification of mast cells--by means of their morphology, fixation and staining characteristics--into two categories (mucosal vs. connective tissue; T-vs. T/C cells) is simplistic, especially since human nasal mast cells are both heterogeneous and pleomorphic.
Animals↗
Differential diagnosis of otitis media and externa.
Explore the source record for details and available documents.
Child↗
The generation of cellular diversity in the cerebral cortex.
We have studied cell lineage in the rat cerebral cortex using retroviral vectors. With this technique, the virus is used to introduce a marker gene into dividing precursor cells such that their fate can be followed. We have studied cell lineage by using this method in the following ways. First, we have labelled germinal cells of the cerebral cortex in vivo during the period of neurogenesis. Second, we have grown cortical precursor cells in dissociated cell culture, and used the viral labelling technique to follow their development in vitro. Both types of study have shown that by the time neurogenesis is under way, the majority of precursor cells are restricted to the production of a single cell type: neurones, astrocytes, or oligodendrocytes. The only exception is a cell we call the N-O cell because it has the ability to generate both neurones and oligodendrocytes. These data suggest that the ventricular zone, the germinal layer of the embryonic cortex, is a mosaic of different precursor cells each with a different restricted potential. However, this restriction of potential of cortical precursor cells does not extend to their ability to contribute to more than one cortical lamina or cytoarchitectonic area. The precursors of both neurones and grey matter astrocytes contribute cells to multiple layers of the cortex. Moreover, in the hippocampal formation, neuronal precursors can contribute cells to more than one hippocampal field.
Aging↗
Recent advances in methodology for analysis of phytate and inositol phosphates in foods.
This review summarises the methods available for the analysis of phytate and structurally related molecules, i.e., inositol polyphosphates. Phytate has been determined by colorimetry, low pressure ion exchange column chromatography, phosphorus-31 fourier transform nuclear magnetic resonance spectroscopy (31P FT NMR), near-infrared reflectance spectroscopy and high performance liquid chromatography (HPLC). Among these techniques anion exchange column chromatography and HPLC were shown to be best suited for separation of inositol phosphates. Since inositol phosphates do not have a characteristic absorption spectrum, their detection in HPLC analysis is limited to methods employing monitoring of refractive index, post column reaction products, conductivity or indirect detection although other detection methods may be feasible. As refractive index detection under isocratic eluent conditions is relatively easy to manipulate, anion-exchange HPLC methods using a low capacity column or ion-pair HPLC methods are recommended for the analysis of inositol phosphates in nutritional studies.
Chromatography↗
Flow and image cytometric DNA analysis in Ewing's sarcoma.
Ewing's sarcoma is the second most common bone tumor in childhood, with an overall 5-yr survival of 40%. It is one of the poorly differentiated small spherical cell tumors frequently requiring distinction from rhabdomyosarcoma, neuroblastoma, osteosarcoma, primitive neuroectodermal tumor, and lymphoma. The majority of rhabdomyosarcomas, neuroblastomas, and osteosarcomas are aneuploid, whereas Ewing's sarcomas are usually diploid. To determine whether there is any correlation between DNA content, morphology, site, and survival in Ewing's sarcoma and extraosseous Ewing's sarcoma, 21 tumor samples were studied retrospectively (3 extraosseous Ewing's and 18 Ewing's sarcomas). The DNA analysis was performed on disaggregated paraffin-embedded tissue nuclei by flow (FCM) and image (IC) cytometry and correlated with the histology and clinical history. The DNA ploidy by FCM on 17 of 18 Ewing's sarcoma samples was 12 diploid, 1 aneuploid, and 4 tetraploid. By IC, the DNA ploidy on 16 samples was 13 diploid, 1 aneuploid, and 2 tetraploid. Three samples were nonevaluable (1 by FCM and 2 by IC). The agreement between FCM and IC was 12 of 16 (75%). The extraosseous Ewing's sarcoma tumors were 2 diploid and 1 aneuploid by IC. In this study there was no correlation between the DNA ploidy and either the histology, site, or survival.
Adolescent↗
In thiamine deficiency, activation of erythrocyte transketolase by thiamine in vivo exceeds activation by cofactor in vitro.
In 60 thiamine deficient patients, the mean erythrocyte transketolase activity after activation by thiamine diphosphate cofactor in vitro, representing the apparent sum of holoenzyme and apoenzyme activities, was 0.609 (SD 0.166) U/g Hb before thiamine therapy and rose to 0.772 (SD 0.152) U/g Hb immediately after the administration of thiamine to the patients. The difference between these values, 0.163 (SD 0.130) U/g, is the mean activity of transketolase protein which can be activated by thiamine in vivo but not by thiamine diphosphate in vitro. This difference correlated with low initial erythrocyte transketolase activity in these patients, but not with their alcohol intake, liver function or diagnoses.
Alcoholism↗
Antithrombin Cambridge II, 384 Ala to Ser. Further evidence of the role of the reactive centre loop in the inhibitory function of the serpins.
Four unrelated individuals have been identified with an identical antithrombin variant, associated in one of them with episodes of recurrent venous thromboses. In each case, the plasma antithrombin concentration was normal and the only function abnormality was a minor but consistent decrease in the heparin-induced thrombin inhibition suggesting a mutation at or near the reactive centre of the molecule. Amplification and direct sequencing of exon 6 showed a G----T mutation at nucleotide 1246, which corresponds to a substitution of a serine for an alanine at residue 384. This is one of a series of conserved alanines that form the stalk to the reactive centre loop. The observed changes in this variant are compatible with recent structural studies that infer that mobility of this stalk with partial re-entry into the A-sheet of the molecule is necessary for optimal inhibitory activity.
Aged↗
Virus infection triggers insulin-dependent diabetes mellitus in a transgenic model: role of anti-self (virus) immune response.
We investigated the potential association between viruses and insulin-dependent (type 1) diabetes (IDDM) by developing a transgenic mouse model. By inserting into these mice a unique viral protein that was then expressed as a self-antigen in the pancreatic islets of Langerhans, we could study the effect on that expressed antigen alone, or in concert with an induced antiviral (i.e., autoimmune) response manifested later in life in causing IDDM. Our results indicate that a viral gene introduced as early as an animal's egg stage, incorporated into the germline, and expressed in islet cells does not produce tolerance when the host is exposed to the same virus later in life. We observed that the induced anti-self (viral) CTL response leads to selective and progressive damage of beta cells, resulting in IDDM.
Animals↗
Clustering of dendrites in the cerebral cortex begins in the embryonic cortical plate.
In this study, we have asked what organizational features can be detected in the embryonic rat cerebral cortex. We have found evidence using light microscopy, and scanning and transmission electron microscopy, that soon after the first cortical neurons join the cortical plate, their apical dendrites form clusters. These clusters are characterized by the close apposition of dendritic membranes, and by intermediate-type junctions. Clustering occurs within 24 h of cortical plate formation, at a time when the cortical plate is about six cell diameters thick, and before the cortex has any afferent input or the cortical plate any synapses. Thus the clustering of apical dendrites in the cortical plate appears to be a very early organizational feature in the development of the cerebral cortex.
Animals↗