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H J Wu

Publications and source records attributed to H J Wu.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Segmental analysis of hair from meperidine abusers and evaluation of the results].

Using meperidine abusers as subjects for this study, we detected in hair meperidine and its metabolites normeperidine, N-OCH3-meperidine and N-AC-meperidine. The content of meperidine and normeperidine of 60 abusers were 103 +/- 130 ng/mg and 117 +/- 143 ng/mg respectively. Meperidine was stably present in hair for at least 20 months. Normeperidine level decreased from hair root to tip. The segmental analysis of hair revealed that there were correlations between the drug abuse history and the distribution of drug along the hair shaft, and between the dose of meperidine and its content presented in hair.

Female↗
PubMed1999

[Determination of heroin metabolites in biological fluids, tissues and hair of heroin addicts using GC/MS-SIM].

Using GC/MS-SIM, we examined morphine distribution in human bodies of 2 delayed death cases and analyzed content of morphine and 6-acetylmorphine (MAM) in hair specimens of 7 cases. After hydrolysis and extraction, MOR and 6-MAM were derived with acetic anhydride or BSTFA and then the derivatives were qualitatively and quantitatively analyzed by GC/MS-SIM. The results indicated that urine, bile and liver were the best samples to reveal the heroin-related deaths. Hair analysis has its unique advantage for its long time of abusing monitor, compared to biological fluids.

Female↗
PubMed1998

Crystallization and preliminary X-ray studies of allophycocyanin from red alga Porphyra yezoensis.

Allophycocyanin from red alga Porphyra yezoensis has been crystallized in three crystal forms. Form 1 crystals with space group P4132 or P4332 and cell parameters a = 286 A, alpha = 90 degrees were obtained by using isopropanol as precipitant. These crystals did not diffract beyond 5.8 A and could not be used in structure analysis. Form 2 crystals were obtained when crystallization conditions were slightly changed by adding 0.2 M magnesium chloride. The space group of form 2 was not determined because it was difficult to get large single crystals. Form 3 crystals were obtained by using ammonium sulfate as precipitant. The space group of form 3 is R32 with cell dimensions a = b = 105.3, c = 189.4 A and one alpha beta unit in the asymmetric unit. These crystals diffract up to 2.06 A resolution and are suitable for structure determination by molecular-replacement methods.

Crystallization↗
PubMed1996

Coherence, cardinal directions and higher-order mechanisms.

Our initial purpose was to develop a quantitative method of estimating the cardinal directions of color space. The method is based on the finding that patterns consisting of pairs of drifting gratings modulated along different cardinal axes appear to slip with respect to one another, while the same patterns appear as a single coherent plaid if the modulation directions of the patterns are rotated by 45 deg in color space [Krauskopf & Farell (1990). Nature, 348,328-331]. A forced-choice procedure was used in which observers were asked to choose which of two successively presented patterns appeared less coherent. The patterns consisted of pairs of drifting gratings; the direction of modulation of one of the gratings was fixed and that of the other varied. For example, an estimate of an individual's isoluminant plane could be obtained by fixing the modulation of one grating in the luminance direction and finding the elevation of the modulation of the other grating that resulted in minimum perceived coherence. We found it important to take into consideration individual differences in the tilt of the isoluminant plane in color space and in the detectability of targets in the nominal cardinal directions. When this was done we found that reliable measurements could be made. The method effectively provided quantitative estimates of the cardinal directions. However, the most important result was the inadequacy of the generalization that patterns appear coherent when they share similar components along cardinal directions (Krauskopf & Farell, 1990) to account for the new results. The present results suggest that patterns appear not to cohere to the extent that they fail to stimulate common chromatic mechanisms, but the assumption that these mechanisms are tuned only along cardinal axes can be rejected. Along with other data the results point to the existence of higher-order mechanisms tuned to different isoluminant chromatic directions.

Color Perception↗
PubMed1996

[The expression of c-myc protein in uterine cervical cancer: a possible prognostic indicator].

Forty-eight cases of human uterine cervical cancer were examined for the expression of c-myc protein by immunohistochemical staining. The overexpression of c-myc was detected in 17 of 48 cases (35%), which is consistent with previous reports. The frequency of c-myc overexpression was not associated with the clinical stage. Relapse was observed in 7 of 15 cases (47%) which had overexpression of c-myc (mean follow-up period: 35 months), whereas relapse was observed in only 3 of 30 cases (10%) which did not overexpress c-myc (mean follow-up period: 33 months). The five-year survival rate was significantly lower in the cases overexpressing c-myc than in those not overexpressing it. This indicates that the overexpression of c-myc may be associated with a high risk of relapse and poor prognosis. We also analysed the correlation between lymph node metastasis, cervical stromal invasion and c-myc overexpression, and did not find any correlation between them. These results suggest that the overexpression of c-myc in cervical cancer may be a prognostic indicator for predictive testing.

Adenocarcinoma↗
PubMed1996

Sequencing and mapping the Arabidopsis genome: a weed model for real crops.

Arabidopsis is a crucifer weed with a small genome of about 120 Mbp which has been chosen as a model species for plant molecular genetics. Four years ago, a consortium of nine French laboratories, including ours, initiated a project aimed at mapping the transcribed regions of the genome. The strategy employed was to systematically and randomly sequence cDNA clones isolated from libraries made from different tissues and organs of plants grown under various physiological conditions. The consortium released about 7,000 expressed sequenced tags (ESTs) in the dbEST database corresponding to approximately 3,500 unique genes. In the next phase of the programme, a YAC library with average inserts of 500 kbp has been prepared. We have now started to use the EST information to map the cDNA clones on these YACs. The most recent aspect of Arabidopsis sequencing is the ESSA (European Scientists Sequencing Arabidopsis) project, in which the aim is to describe 2.5 Mbp by the end of 1996. Genomic sequencing has revealed a very high gene density. Comparison of present genomic sequencing results with the EST data suggests that up to half of the genes might already be tagged with an EST. In collaboration with Carlos Quiros' group in Davis we have also analysed the conservation of a 30 kbp locus (Em 1, a late embryogenesis abundant protein gene) on chromosome 3 between Arabidopsis and several Brassica species. Progress on these various aspects will be reviewed. We shall also present some sequence comparisons between Arabidopsis and rice ESTs. These results suggest that it should be possible in the very near future to map a pool of common genes onto many different plant genomes. This should provide a common framework to integrate maps from different species and facilitate mapbased cloning of genes of agronomical importance.

Arabidopsis↗
PubMed1995

A chlorophyll synthetase gene from Arabidopsis thaliana.

During the course of an Arabidopsis thaliana genome sequencing project, we identified a gene, G4, with a derived amino acid sequence showing homology to the product of the Rhodobacter capsulatus bchG locus which is involved in the esterification of bacteriochlorophyllide with geranylgeraniol. The relationship between this gene and bchG was confirmed by the isolation and analysis of a corresponding full-length cDNA. Comparison of genomic and cDNA sequences indicated that the gene is made up of 14 exons, some of them being very short. Southern and Northern analyses showed that this sequence represents a single-copy gene and its transcript is detected only in green or greening tissues. Both homologies and expression data suggest that this gene encodes a chlorophyll synthetase, one of the last enzymes of chlorophyll biosynthesis, and thus represents a new example of a nuclear gene encoding an enzyme of this pathway in higher plants.

Amino Acid Sequence↗
PubMed1993

Processing of chromaffin granule proteins: a profusion of proteases?

Evidence suggests that proenkephalin and members of the chromogranin/secretogranin family of proteins are prohormone precursors, giving rise to a variety of peptides with biologic activity. However, the specific proteases responsible for cleaving these proteins in vivo have not been fully established. Several candidate proteases have been described, some of which have been shown to cleave these proteins in vitro. Proteolytic processing of the chromogranins may be particularly complex, occurring in specific tissue-dependent patterns. To account for this level of complexity several protease systems may be operative, either alone or in concert, both within the neurosecretory granule and in the extracellular space. Specific proteases which are available within neurosecretory cells or in the local extracellular environment, and which may cleave these prohormones include PC1 and PC2 (recently described members of the Kex2/furin family of endoproteases), as well as kallikrein, acetylcholinesterase, and, more recently, the plasminogen/plasmin protease system. The potential role of these specific proteases in the processing of proenkephalin and the chromogranins is discussed, in particular, in the context of possible processing clues available from recent analysis of cDNA and genomic intron/exon structure.

Animals↗
PubMed1993

Secretory protein traffic. Chromogranin A contains a dominant targeting signal for the regulated pathway.

Secretory proteins are targeted into either constitutive (secreted upon synthesis) or regulated (stored in vesicles and released in response to a secretagogue) pathways. To investigate mechanisms of protein targeting into catecholamine storage vesicles (CSV), we stably expressed human chromogranin A (CgA), the major soluble protein in human CSV, in the rat pheochromocytoma PC-12 cell line. Chromaffin cell secretagogues (0.1 mM nicotinic cholinergic agonist, 55 mM K+, or 2 mM Ba++) caused cosecretion of human CgA and catecholamines from human CgA-expressing cells. Sucrose gradients colocalized human CgA and catecholamines to subcellular particles of the same buoyant density. Chimeric proteins, in which human CgA (either full-length [457 amino acids] or truncated [amino-terminal 226 amino acids]) was fused in-frame to the ordinarily nonsecreted protein chloramphenicol acetyltransferase (CAT), were expressed transiently in PC-12 cells. Both constructs directed CAT activity into regulated secretory vesicles, as judged by secretagogue-stimulated release. These data demonstrate that human CgA expressed in PC-12 cells is targeted to regulated secretory vesicles. In addition, human CgA can divert an ordinarily non-secreted protein into the regulated secretory pathway, consistent with the operation of a dominant targeting signal for the regulated pathway within the peptide sequence of CgA.

Amino Acid Sequence↗
PubMed1993

Total ankle replacement: preliminary report of 3 cases.

Total Ankle Replacement has been quite limited used currently and ankle arthrodesis is still the treatment of choice for most disabling arthritic disease of the ankle because of the generally poor long term results of ankle replacement. In spite of its popularity, ankle arthrodesis has many disadvantages, including long immobilization, high pseudoarthrosis rate, and load shift with increased stress on the neighboring joints of ankle. Total ankle replacement may be tried on some selected cases, such as on older patients or on patients with bilateral ankle lesions, multiple joints involved arthritis, such as rheumatoid arthritis etc. This paper reports three ankle replacements with a two year follow up, and they all have encouraging short term results. In the future, the development of a more effective ankle replacement seems to be likely. But at the present time, only carefully choosing the available prosthesis and strictly selecting the indicated patient can make the total ankle replacement acceptable.

Adult↗
PubMed1991

Structure and function of the chromogranin A gene. Clues to evolution and tissue-specific expression.

Chromogranin A is the index member of a family of acidic proteins stored and released throughout the neuroendocrine system with peptide hormones and neurotransmitters. To better understand its functional domains, its evolutionary lineage, and the basis of its tissue-specific pattern of expression, we obtained a mouse chromogranin A cDNA and used it to isolate the chromogrannin A gene from the mouse genome. We then characterized the gene's exon/intron structure, and the structure and function of its 5'-regulatory region (promoter/enhancer). The chromogranin A gene was complex, its eight exons and seven introns spanning about 11 kilobase pairs. The eight exons displayed some correspondence to putative functional domains suspected within the cDNA-deduced primary structure of the protein. Three exons also displayed both length and sequence homology to exons in another member of the chromogranin/secretogranin family, chromogranin B, suggesting an evolutionary relationship. A 1.2-kilobase pair genomic fragment just 5' of the coding region was able to program cell type-specific gene expression in a transfection/reporter system. Both pituitary corticotropes and adrenal chromaffin cells recognized this promoter. The promoter possessed some known consensus transcriptional control elements (TATA box, cyclic AMP-response element, and Sp1 site), but otherwise novel transcriptional control elements seem to be operative. The results suggest that this complex gene is encoded by exon modules with evolutionary links to homologous modules in other chromogranin/secretogranin protein family members, and that the 5'-flanking region of the gene is sufficient to confer neuroendocrine tissue-specific expression of the chromogranin A gene.

Amino Acid Sequence↗
PubMed1991

Crystal growth kinetics of theophylline monohydrate.

The crystal growth kinetics of theophylline monohydrate from aqueous buffered supersaturated solutions were investigated at 10, 20, 30, and 40 degrees C. Crystallization experiments were carried out isothermally at pH 6. During growth the crystal count and size distributions were monitored in situ. The growth rate was evaluated from the rate of change of the size with time at a constant value of the size distribution. The growth rate is independent of the stirring rate and the activation energy for growth is higher than the value for simple diffusion, 14.3 and 4.4 kcal/mol, respectively. This indicates that crystal growth of theophylline monohydrate is controlled by a surface reaction mechanism rather than by solute diffusion in the bulk. The growth-rate dependence on the supersaturation was compared with crystal growth theories. The data are described by the screw dislocation model and by the parabolic law, suggesting a defect-mediated growth mechanism rather than a surface nucleation mechanism.

Crystallization↗
PubMed1991

Digital skin bloodflow of patient rested on different positions--a laser Doppler study.

Brachial plexus injuries resulting from malposition of the patient during general anesthesia have been described in the medical literature for nearly a century. However, concerning the brachial vessels which were accompanying the nervous plexus, few papers can be found discussing the changes that also occur when malpositing. In this study, an attempt was made to measure changes of digital skin bloodflow among patients resting in different postures simulating the operating postures in orthopaedic surgery. Laser doppler was found to be a sensitive indicator of skin bloodflow and peripheral vascular diseases. The results show that axillary pad used with patients resting in decubital positions does not change digital skin bloodflow or elbow flexion which could serve to reduce nervous tension among those patients whose digital skin bloodflow remains unchanged by hyperabductive shoulder positions. These findings do not support the preferred shoulder positions which are suggested in most papers discussing brachial plexus. From this it may be concluded that digital bloodflow is not occluded in healthy persons either by body postures or by the positions of the shoulders and elbows.

Adult↗
PubMed1990

Platelet-fibrin interaction in the suspension and under flow conditions.

Interactions between platelets and fibrin are important in hemostasis but often confused with platelet-fibrinogen interactions. A stirred mixture of solubilized fibrin and washed platelets at neutral pH range showed drastic reduction in turbidity and concomitant platelet adhesion onto newly formed fibrin strands. This platelet-fibrin interaction did not require platelet activation nor did it cause platelet aggregation. A device consisting of a parallel-plate flow chamber mounted on a fluorescence microscope has been constructed to allow direct visualization and recording of platelet-fibrin interaction under flow conditions. Platelets in whole blood adhered to the fibrin-coated portion but not to the uncoated portion of the flow chamber. Slow motion playback of video tapes indicated that the adhesion phenomenon was a dynamic process that involved attaching, detaching, relocation and transient contact. The fibrin coating influenced platelet adhesion both by increasing the number of cells making short-term attachments to the surface and by increasing the duration of cells attached to the surface. These observations provided basic characteristics of platelet-fibrin interaction.

Blood Platelets↗
PubMed1990

Molecular cloning, structure, and expression of dopamine-beta-hydroxylase from bovine adrenal medulla.

Dopamine-beta-hydroxylase (DBH), the enzyme that catalyzes the conversion of dopamine to norepinephrine, remains the topic of many unanswered questions. We isolated DBH cDNA clones from a bovine adrenal medulla cDNA library in the vector lambda gt10. The longest cDNA had an open reading frame encoding an entire mature DBH 578 amino acid (64,808 dalton) polypeptide chain, though lacking a portion of the signal peptide. Additional 5' clones, obtained by the polymerase chain reaction, established the sequence of a 19 amino acid signal peptide. The mature protein sequence was 84% homologous to that of human pheochromocytoma DBH, including preservation of four potential copper ligand sites (HH or HXH) and substrate binding domains. There were no hydrophobic (putative membrane spanning) domains, other than the signal peptide. All available DBH peptide and protein sequence data can be accounted for by the cDNA-deduced 578 amino acid mature protein primary structure. Prokaryotic DBH expression yielded a 65-kilodalton DBH-immunoreactive peptide that differed from eukaryotic adrenal DBH only in N-linked, endoglycosidase F-sensitive glycosylation in the latter. Southern analysis suggested one DBH gene, whereas Northern analysis suggested a single 2.6 kbp tissue-specific DBH transcript. Comparison of the DBH primary structure with other reported sequences [Protein Identification Resource (PIR), New Atlas (NEWAT)] did not indicate that DBH is a member of any known gene family. The results suggest that a single DBH gene encodes a message specifying a single DBH polypeptide chain.

Adrenal Medulla↗
PubMed1990

Correction osteotomy of flexion deformity of cervical spine in ankylosing spondylitis--a case report.

It is well known that severe flexion deformities of the spine may occur in patients suffering from ankylosing spondylitis. The prevention of these deformities by early recognition of the disease process should be the main aim of the medical profession in handling patients with specific spinal involvements. Yet, we still see all too often patients with advanced kyphotic deformities of the trunk who are very grossly disabled and thus present a major problem to definitive surgical correction of their deformities. Correction of rigid kyphosis by establishing a compensatory lordosis can be carried out in the lumbar or cervical area. Surgical intervention in the cervical region enables the chin to be lifted off the sternum, but great care has to be taken of the relatively bulky spinal cord, which practically fills the spinal canal. Excessive correction runs the risks of fatally damaging the nerves and vertebral vessels. Therefore, most centers perform correction osteotomies of the cervical spine progressively, with day-by-day adjustment of the external fixators. We present a case of cervical osteotomy in which, under local anesthesia and with the aid of S.S.E.P., cervical kyphosis was corrected by a one-stage procedure. The results and difficulties are described here-in.

Adult↗
PubMed1990

Ipsilateral hip and femoral shaft fractures treated with compression hip screw and long side-plate.

Complex femoral fractures involving the hip and shaft are not rare findings in the emergency room. The primary problem in the care of these patients is the preservation of their lives. The fracture combination under discussion is only a part of the injury complex sustained by these individuals. After the acute problems have been brought under control, care of the fractured femur and hip must be planned. Recently, most centers have favored giving priority to hip fractures, rigid fixation and early mobilization. However, for the fixation implants, variable fixation methods have been reported but are imperfect. In the past 5 years we have had some experience using compression hip screws with long side-plate to fix the different injured parts of these dual shaft and hip fractures at the same time. It seemed that application of these devices in dual hip and proximal shaft fractures, which are devoid of physiological bowing of the shaft, would get the best results. But when they are applied to dual fractures of the hip and the middle portion of the shaft, certain techniques, like adequate distal fixation, the prebending of the plate, primary bone graft and mobilization of the non-weight bearing pattern should be strictly adhered to for assurance of early callus formation and prevention of implant failure.

Adult↗