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Biomedical subjects

D P Green

Publications and source records attributed to D P Green.

At least 19 recordsLinked to original sources
PubMed2001

Herniation of the lung after video-assisted thoracic surgery.

We report a case of lung herniation occurring following video-assisted thoracic surgery. Although lung hernias are rare, the widespread application of video-assisted thoracic surgery to patients at risk for lung hernia will likely result in more reports in the future. Consequently, pulmonologists and thoracic surgeons must be aware of this condition, risk factors for development, and potential methods of prevention in order to minimize the occurrence of this complication.

Aged↗
PubMed2001

A set of 840 mouse oocyte genes with well-matched human homologues.

GenBank contains 14 477 expressed sequence tags (EST) derived from mouse oocyte cDNA libraries: 3499 of these are from two unfertilized oocyte libraries and 10 978 are from two fertilized oocyte libraries. Gene expression profiles were obtained for these libraries by matching library EST to UniGene clusters. The 14 477 EST identified 4226 UNIGENES: These were screened using HomoloGene to identify 1386 homologous UniGene clusters in two other species with one of the matches being human. Within these human matches, 840 encoded named proteins, 223 encoded hypothetical proteins, and 323 encoded clustered EST. The set of named genes provides the first step in establishing a database of genes expressed in mouse oocytes and, by extension, human oocytes.

Animals↗
PubMed2001

Meta-analysis of gene expression in mouse preimplantation embryo development.

Mammalian preimplantation development is characterized by a number of major events. These potentially involve significant but transient changes in early embryonic gene expression. We have undertaken a meta-analysis of gene expression in mouse preimplantation development using a set of 71 346 expressed sequence tags (EST) derived from 15 non-normalized cDNA libraries. These libraries span seven stages of development from the unfertilized oocyte to the blastocyst stage. EST were clustered using UNIGENE: The 71 346 EST identified 11 483 separate genes, of which 1585 are not found elsewhere in the mouse. Aggregate sets of EST for each of the seven stages were analysed for differences in gene expression using Fisher's exact test. This analysis identified 109 genes that were differentially expressed. Some of these genes were associated with degradation of transcripts at the 1-cell stage whereas other genes underwent increased expression at the blastocyst stage. The set of 11 483 genes identified in mouse preimplantation embryo development provides the starting point for the design of DNA microarrays targeted at early mammalian embryogenesis. By anchoring the analysis of mouse preimplantation development in UniGene, it will be possible to identify homologous genes that are likely to be involved in human preimplantation embryo development.

Animals↗
PubMed2000

Molecular phenotype of the human oocyte by PCR-SAGE.

Consecutive application of PCR and serial analysis of gene expression (SAGE) was used to generate a catalog of approximately 50, 000 SAGEtags from nine human oocytes. Matches for known genes were identified using the National Institutes of Health SAGEtag database. This database links directly to the UniGene database, providing rapid discrimination between SAGEtags that match known genes and expressed sequence tags and those that currently have no match. Matches in the oocyte SAGE catalog were found for surface receptors, second-messenger systems, and cytoskeletal, apoptotic, and secreted proteins. Many of these proteins were not previously known to be expressed in mammalian oocytes. The relative abundances of transcripts for cytoskeletal proteins and proteins known to be in oocytes are consistent with their documented expression, suggesting an absence of representational distortion by the PCR step. The expression profile of the human oocyte may help identify factors that reprogram somatic cell nuclei to totipotency.

Databases, Factual↗
PubMed1999

Does canvassing increase voter turnout? A field experiment.

This paper reports the results of a randomized field experiment involving registered voters in the city of New Haven. Nonpartisan get-out-the-vote messages were delivered through personal canvassing shortly before the November 1998 election. We find that personal canvassing increased voter turnout by approximately 6. The effect of personal contact seems to be slightly smaller for voters registered with a major political party and higher for unaffiliated voters, although the hypothesis that all voters are equally affected could not be rejected. Study of several alternative political messages provided equivocal evidence suggesting the superiority of a canvassing appeal that emphasizes the closeness of the election.

Journal Article↗
PubMed1999

Static, dynamic, and causative bipolarity of affect.

In what sense are pleasant and unpleasant moods "bipolar"? One must differentiate three types of affective bipolarity: static bipolarity (the zero-order correlation between measures of pleasant and unpleasant affect, net of distortions due to measurement error, tends to be strongly negative), dynamic bipolarity (pleasant and unpleasant feelings generally change in opposite directions and to approximately the same extent), and causative bipolarity (the influence of pleasant and unpleasant affect on other variables is approximately equal and opposite). It is argued that static bipolarity is often attenuated by measurement error, dynamic bipolarity can be masked by asymmetrical scaling artifacts, and causative bipolarity is often obscured by both. The experience and influence of pleasant and unpleasant affect may occur along bipolar lines even if the sources of these feelings are understood as physiologically separable systems with distinct neurological loci.

Affect↗
PubMed1999

Use of mutant strain for evaluating processing strategies to inactivate Vibrio vulnificus in oysters.

Vibrio vulnificus is a ubiquitous marine bacterium frequently isolated from shellfish and associated with severe and often fatal disease in humans. Various control strategies to reduce the disease risk associated with V. vulnificus contamination in shellfish have been proposed. However, evaluating the efficacy of these control strategies is complicated because of the difficulty in distinguishing V. vulnificus from the high levels of background environmental Vibrio spp. The purpose of this research was to develop a model indicator V. vulnificus strain that could be readily differentiated from background microflora and used to facilitate the evaluation of processing efficacy. A spontaneous nalidixic acid-resistant strain of V. vulnificus (Vv-NA) was prepared from a wild-type parent (Vv-WT) using selective plating techniques. Vv-NA was very similar to Vv-WT with respect to biochemical characteristics, appearance on selective plating media, detection limits using most probable number and polymerase chain reaction, and growth rate. In comparative freeze inactivation studies on pure cultures, Vv-WT and Vv-NA had similar freeze inactivation profiles at -20 degrees C (conventional freezing), at -85 degrees C (cold blast freezing), and in liquid nitrogen (cryogenic freezing). In oyster homogenates artificially inoculated with Vv-NA, the organism was inactivated 95 to 99% after freezing, irrespective of freezing temperature. Thermal inactivation comparisons of pure cultures of Vv-WT and Vv-NA using the capillary tube method revealed statistically significant differences in D values at 47 degrees C (2.2 versus 3.0 min, respectively) and 50 degrees C (0.83 versus 0.56 min, respectively), but nearly identical values at 52 degrees C (0.21 versus 0.22 min, respectively). However, these D values were notably higher than those reported by other investigators and hence provided a conservative means by which to evaluate thermal inactivation. In oyster homogenates seeded with Vv-NA, D values of 1.3+/-0.09 min and 0.41+/-0.01 min were obtained at 46 degrees C and 48 degrees C, respectively. This study demonstrated that Vv-NA is readily enumerated and could be used as a surrogate for evaluating the degree of V. vulnificus inactivation provided by freezing and thermal treatments of oyster homogenates.

Animals↗
PubMed1998

From lynching to gay bashing: the elusive connection between economic conditions and hate crime.

Trends in bigoted violence are often explained by reference to frustrations arising from macroeconomic downturns. Historical and recent time-series studies have turned up significant links between economic conditions and lynchings of Blacks in the pre-Depression South (e.g., Hepworth & West, 1988; Hovland & Sears, 1940). However, replicating the time-series analyses of lynching, extending them through the Great Depression, and applying similar techniques to contemporary data fail to provide robust evidence of a link between economic performance and intolerant behavior directed against minorities. The authors speculate that the predictive force of macroeconomic fluctuation is undermined by the rapid rate of decay in the frustration-bred aggressive impulse and the absence of prominent political actors affixing economic blame on target groups.

Adult↗
PubMed1997

The mammalian acrosome reaction: gateway to sperm fusion with the oocyte?

Mammalian sperm undergo discharge of a single, anterior secretory granule following their attachment to the zona pellucida surrounding the oocyte. This secretory discharge is known for historical reasons as the acrosome reaction. It fulfils a number of purposes and without it, sperm are unable to penetrate the zona pellucida and fuse with the oocyte. In this review, we focus on the role of the acrosome reaction in the development of fusion competence in sperm. Any naturally occurring membrane fusion has two major sequential steps: a docking or adhesion step, in which two membranes adhere, and a fusion step, in which their lipid bilayers are destabilized and merged and a cellular compartment is either created or destroyed. Recent evidence suggests that there is an important role for oocyte integrins and sperm-bound disintegrins in mammalian sperm/oocyte adhesion and fusion. The fusion mechanism employed by sperm remains poorly understood, however, and circumstantial evidence suggests it is more complex than the interaction between a single protein species and its target. Sperm/oocyte fusion is probably the most accessible eukaryotic model for intercellular fusion currently available, partly because it is temporally separated from gene expression. Elucidation of the mechanism of sperm/oocyte fusion may throw light on the mechanism of other intercellular fusions such as myoblast fusion, and the evolutionary relationship of intercellular membrane fusion to intracellular membrane fusion.

Acrosome↗
PubMed1997

Three-dimensional structure of the zona pellucida.

The zona pellucida is the extracellular coat that surrounds the mammalian oocyte. It forms a spherical shell of remarkably uniform thickness (5-10 microns in eutherian mammals). The mouse is currently the largest source of data on the zona pellucida and this review is built largely on these data. The zona pellucida is composed of three proteins in both mice and humans: ZP1, ZP2 and ZP3. These proteins are glycosylated and, in mice, have mature relative molecular masses of 200,000, 120,000 and 83,000, respectively. ZP1 is a dimer of two apparently identical subunits. All three mouse proteins have been sequenced and possess transmembrane domains at their C-terminal ends coupled with furin cleavage sites immediately upstream. Sequence data have been used to provide an accurate assessment of the mole ratios of the three proteins. The ratio of ZP2:ZP3 is close to 1:1, whereas ZP1 is approximately 9% of the combined mole amounts of ZP2 and ZP3. Ultrastructural evidence suggests that the mouse zona pellucida is composed of filaments constructed by head-to-tail association of globular proteins. The coordinate synthesis of the three zona pellucida proteins coupled with the near 1:1 stoichiometry of ZP2 and ZP3 is consistent with a model in which ZP2-ZP3 heterodimers are the basic repeating units of the filament, with cross-linking of filaments by dimeric ZP1. This model is also consistent with data from ZP2 and ZP3 gene knockout and antisense experiments. However, the structure remains unproven. The small amount of ZP1 relative to ZP2 and ZP3 may have important implications for the distribution of ZP1 cross-links, since the number of cross-linking sites potentially exceeds the number of ZP1 dimer molecules by a considerable margin. The evidence that ZP1, ZP2 and ZP3 are all synthesized via a membrane-bound step is discussed and two models are proposed for the assembly of the zona pellucida. The cortical reaction and its effect on the zona pellucida are examined in detail. It is shown that the amount of material released by cortical granules could be of the order of 30% by mass of ZP1, and that if this material was distributed predominantly on the inner face of the zona pellucida, its local concentration could approach that of ZP1. A model in which the zona block to polyspermy is caused by direct titration of zona pellucida binding sites is suggested as an alternative to the explanation that relies on enzyme cleavage of ZP2 to ZP2f. Finally, some of the major experimental and structural issues that remain to be addressed are identified.

Animals↗
PubMed1996

Quality characteristics of fresh blue crab meat held at 0 and 4 degrees C in tamper-evident containers.

There has been a regulatory movement toward the required use of tamper-evident containers for fresh blue crab meat. North Carolina passed tamper-evident regulations in 1993. Blue crab processors had little information on possible changes in head-space gases, microbial growth, chemical decomposition, sensory quality, or shelf life caused by the new containers. Chemical, microbiological, physical, and sensory changes in fresh crab meat were monitored during 18 days of storage in ice and 13 days of storage refrigerated at 4 degrees C. "Special" blue crab meat, chosen for the study, is the least expensive commercial form of white crab meat. The crab meat was packaged in four retail containers: copolymer polyethylene cups with polyethylene snap-on lids, copolymer polyethylene cups with snap-on polyethylene lids fastened to the cup with heat-shrink low-density polypropylene seals, copolymer polyethylene cans with aluminum easy-open ends, and copolymer polypropylene cups with a tamper-evident pull-tab on the lid. Control samples packaged in industry standard copolymer polyethylene cups maintained higher oxygen levels than meat stored in tamper-evident containers. No consistent differences in quality or shelf life were detected among the containers. Market shelf life was limited to 6 days for meat held at 4 degrees C and 15 days for meat held at 0 degrees C. Sensory quality deteriorated 6 days earlier for crab meat held at 4 degrees C than meat held at 0 degrees C. Collateral work showed that toxin production by Clostridium botulinum neither occurred following 18 days of storage at 4 degrees C nor after 15 days of storage at 10 degrees C. Definite spoilage occurred before any toxin production. The study suggests that blue crab processors can safely use the new tamper-evident packaging, which has little or no effect on product quality or shelf life. Processors may choose appropriate packaging options using price, packaging quality, market appearance, and ease of production as the deciding criteria.

Animals↗
PubMed1995

Monoclonal antibodies which recognize equatorial segment epitopes presented de novo following the A23187-induced acrosome reaction of guinea pig sperm.

Acrosome-intact mammalian sperm can adhere to zona pellucida-free oocytes but are only capable of fusing if they have previously undergone the acrosome reaction. This suggests that the acrosome reaction results in presentation of at least one novel epitope which plays a role in sperm-oocyte fusion. Monoclonal antibodies were raised against unfixed acrosome-reacted guinea pig sperm and screened by indirect immunofluorescence for binding to the equatorial segment. They were back-screened against unfixed acrosome-intact sperm for absence of binding. Using this approach, two antibodies, G11 and M13, were identified which detect equatorial segment epitopes presented de novo by sperm following an A23187-induced acrosome reaction. The localization of these epitopes to the equatorial segment was confirmed at the ultrastructural level by indirect immunogold-labelling. Fluorescein isothiocyanate-labelled Fab fragments of these two antibodies also localized to the equatorial segment. Affinity chromatography and western blotting established that the two mAbs recognize the same proteins, which have M(r)s of 34, 46, 48 and 51 x 10(3). When sperm were induced to undergo the acrosome reaction with A23187 and incubated with their discharged acrosomal contents, a further band was produced with an M(r) of 30 x 10(3). Production of this band was inhibited in the combined presence of 100 microM phenylmethylsulphonyl fluoride and 100 microM p-aminobenzamidine even though these compounds do not inhibit acrosomal exocytosis. Neuraminidase and O-glycosidase were without effect on the proteins detected by antibodies G11 and M13. Endoglycosidase F, however, eliminated the bands of M(r) 46, 48 and 51 x 10(3) and replaced them with a strong band of M(r) 44 x 10(3) and two minor bands of M(r) 43 and 45 x 10(3). Formaldehyde fixation of acrosome-intact sperm caused partial rupture of the acrosome with loss of the characteristic rouleaux (stacks) of guinea pig sperm. Indirect labelling of these formaldehyde-fixed sperm with fluorescein isothiocyanate- or gold-labelled second antibody, with or without permeabilization with 0.05% Triton X-100, showed dense labelling on the cytoplasmic face of the plasma membrane overlying the convex surface of the acrosome but little labelling elsewhere. Cryosections of acrosome-intact sperm labelled indirectly with immuno-gold showed labelling consistent with the same location, as well as sporadic labelling at other intracellular sites overlying the acrosome. Since there is no evidence that sperm can translocate intact membrane protein from the cytoplasmic face to the extracellular face of the plasma membrane during the acrosome reaction, the evidence suggests that there are two isolated antigen pools.(ABSTRACT TRUNCATED AT 400 WORDS)

Acrosome↗
PubMed1995

Practice variability and transfer of a racket skill.

This study used a forehand hitting task to explore the effect of racket variability on 'out of range' transfer. 48 11-yr.-old girls were randomly assigned to four treatment groups of Random Variability, Blocked Variability, Specific, and Control. The experimental groups had 32 trials for 4 successive days after which all groups were tested on 4 transfer conditions. Retention tests were given after 1, 4, and 8 days and the data were examined for treatment, range, and occasion effects. Analysis showed the superiority of practice over no practice, variable over specific practice, and random over blocked variability for transfer with two 'out of range' dimensions. Accuracy decayed between the transfer tests. These results are consistent with schema theory, and it is recommended that physical education teachers should focus variable practice on task dimensions that are new to their classes.

Child↗
PubMed1994

Fluorescence photooxidation with eosin: a method for high resolution immunolocalization and in situ hybridization detection for light and electron microscopy.

A simple method is described for high-resolution light and electron microscopic immunolocalization of proteins in cells and tissues by immunofluorescence and subsequent photooxidation of diaminobenzidine tetrahydrochloride into an insoluble osmiophilic polymer. By using eosin as the fluorescent marker, a substantial improvement in sensitivity is achieved in the photooxidation process over other conventional fluorescent compounds. The technique allows for precise correlative immunolocalization studies on the same sample using fluorescence, transmitted light and electron microscopy. Furthermore, because eosin is smaller in size than other conventional markers, this method results in improved penetration of labeling reagents compared to gold or enzyme based procedures. The improved penetration allows for three-dimensional immunolocalization using high voltage electron microscopy. Fluorescence photooxidation can also be used for high resolution light and electron microscopic localization of specific nucleic acid sequences by in situ hybridization utilizing biotinylated probes followed by an eosin-streptavidin conjugate.

Animals↗
PubMed1993

Wrist arthrodesis in post-traumatic arthritis: a comparison of two methods.

The Arbeitsgemeinschaft für Osteosynthesefragen arthrodesis technique is compared with the proximal row carpectomy technique with radiocapitohamate arthrodesis for patients with traumatic and degenerative arthritis of the wrist. Both techniques gave satisfactory functional and x-ray film results in 85% of the patients. Grip strength measured on the Jamar dynamometer at settings 1-5 was 77-83% of the opposite in the dominant extremities and 56-82% of the opposite in the nondominant extremities. Despite the decrease in grip strengths after wrist fusion, grip strength curve patterns were similar for operated and nonoperated extremities. There were no statistically significant differences in grip strength between the two groups. Patients who did not have index and long ray carpometacarpal joints fused had pain at that level requiring a second procedure to arthrodese the joints. Index and long finger carpometacarpal joint arthrodesis at the time of wrist arthrodesis is recommended in patients with heavy labor jobs.

Adult↗
PubMed1993

The patchy configuration of scaphoid avascular necrosis.

The proximal poles of five patients with presumed avascular necrosis of the scaphoid, mostly the result of nonunion, were analyzed histologically for true, pathologically confirmed avascular necrosis of bone. Each specimen was reviewed both qualitatively by an experienced bone pathologist and quantitatively with the use of a computerized image analysis system. Avascular necrosis was found to be variable from one specimen to another as well as within each specimen. Midcentral levels showed a statistically significant greater degree of avascular necrosis than either adjacent palmar or dorsal zones. Both viable and nonviable areas of avascular bone were found in an unpredictable, irregular (patchy) distribution, often in direct apposition to one another. It is apparent from this study that random biopsy alone cannot accurately predict the histologic status of the entire specimen; the clinician must rely on other methods to determine scaphoid viability.

Biopsy↗
PubMed1993

Measurement error masks bipolarity in affect ratings.

For years, affect researchers have debated about the true dimensionality of mood. Some have argued that positive and negative moods are largely independent and can be experienced simultaneously. Others claim that mood is bipolar, that joy and sorrow represent opposite ends of a single dimension. The 3 studies presented in this article suggest that the evidence that purportedly shows the independence of seemingly opposite mood states, that is, low correlations between positive and negative moods, may be the result of failures to consider biases due to random and nonrandom response error. When these sources of error are taken into account using multiple methods of mood assessment, a largely bipolar structure for affect emerges. The data herein speak to the importance of a multi-method approach to the measurement of mood.

Adult↗