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Biomedical subjects

E Wu

Publications and source records attributed to E Wu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Pericardial devascularization combined with Latarjet's innervation in the treatment of patients with portal hypertension.

OBJECTIVE: To study the effect of pericardial devascularization combined with Latarjet's innervation on portal hypertension. METHODS: Forty-eight patients undergoing pericardial devascularization combined with Latarjet's innervation were compared with 57 patients with devascularization. Clinical results were evaluated by postoperative portal vein pressure, postoperative rebleeding, operative mortality, abdominal distension, sudden diarrhea, and gastric retention. RESULTS: The incidence of rebleeding, mortality, abdominal distension, sudden diarrhea, and gastric retention was 2%, 6.3%, 6.3%, 4.2% and 0% respectively in pericardial devascularization combined with Latarjet's innervation, and 12.5%, 12.3%, 24.6%, 15.6% and 14% respectively in devascularization. CONCLUSIONS: Pericardial devascularization combined with Latarjet's innervation preserves the normal function of gastric emptying. This method plays an important role in maintaining nutritional supply and digestive function.

Adult↗
PubMed1998

Few point mutations in elongation factor-1gamma gene in gastrointestinal carcinoma.

Elongation factor-1 (EF-1) gamma is overexpressed in a high proportion of gastrointestinal cancers. The mechanism of overexpression has not been determined. The purpose of this study was to examine cDNA specimens from pancreatic and colorectal cancer for mutation in this gene, which would allow us to determine whether gene mutations are responsible for overexpression of EF-1gamma. In one colorectal carcinoma, we detected an A-->G transition at amino-acid codon 158 (T-->C in the sense strand) resulting in a change from a leucine to a serine. The base change was not detected in cDNA isolated from normal-appearing tissue from the same patient. We did not find mutations in another five colorectal carcinoma and five pancreatic cancer samples. Thus, although we detected a mutation in one tumor, the frequency of mutations was too low to account for the high frequency of overexpression of the EF-1gamma RNA in colorectal cancer. We also investigated other possible mechanisms of overexpression of the EF-1gamma RNA in this study. Slot-blot analysis of DNA isolated from colorectal cancers showed that the overexpression was not due to gene amplification. Using serum starvation to synchronize cultured cells, we showed that the overexpression was also not due to an increase in the number of cycling cells, as occurs in cancer. Using Southern blot analysis, we were unable to detect genome rearrangements that could have been responsible for the overexpression. In conclusion, the mechanism for overexpression of the EF-1gamma gene in colorectal and pancreatic cancer remains unknown. However, mutations in the coding sequence of the gene, gene amplification, and gene rearrangement do not account for the high frequency of overexpression of this gene, and the overexpression is not due to an increase in the number of cycling cells.

3T3 Cells↗
PubMed1998

Characterization of soybean lipoxygenase immobilized in cross-linked phyllosilicates.

Lipoxygenase (LOX) is an enzyme that regioselectively introduces the hydroperoxide functionality into polyunsaturated fatty acids, such as linoleic acid (LA). Hydroperoxide derivatives of polyunsaturated fatty acids are of interest because they can serve as important intermediates in the synthesis of chemical and pharmaceutical compounds. In this study, LOX was immobilized in dispersed phyllosilicate layers that were cross-linked with silicate polymers formed by the hydrolysis of tetramethyl orthosilicates. The effects of substrate concentration, reaction temperature and solvent participation were studied on the oxidation of LA by LOX. The temperature optimum for the oxidation of LA by immobilized LOX was 25 degrees C and values of Km and Vmax for this reaction were 1.7 mM and 0.023 micromol/min respectively. Enzymic activity was stimulated by the addition of 10% (v/v) iso-octane to the reaction mixture. The immobilized LOX preparation showed a degree of substrate preference that demonstrated that 1,3-dilinolein was a better substrate than LA in the oxidation reaction, followed in order by 1-monolinolein, methyl oleate and trilinolein. In general, LOX immobilized in cross-linked phyllosilicates retained the physical and chemical characteristics of free LOX.

Diglycerides↗
PubMed1998

[Antiretroviral therapy. Announcement of the Advisory Committee of the Chilean Society of Infectology on AIDS].

There are treatments to induce the long term suppression of viral replication and that delays the progression of HIV disease. To be effective, these treatments require the uninterrupted use of a combination of drugs (ideally three), patients must be highly compliant, must be instituted in early stages of the disease and drugs must be used for prolonged periods and given by specialists. These treatments are indicated in all symptomatic patients and in those with early immunologic deterioration or high viral load. Recent infection and acute primary retroviral infections should also be considered for treatment. The treatment sponsored and financed by the ministry of health for its beneficiaries is insufficient at this time, since it is received by a minority of eligible patients due to budgetary reasons, and only two drugs are given which is considered such optimal by most experts. The committee considers that the responsibility for financing, providing and delivering these treatments in proper combination and dosages exceeds the duty of the Ministry of Health and should include all the involved parties. However, the state and its official institutions have a special responsibility to provide with adequate treatments to the poorer segments of our population. They also should promote, supervise and control the proper access of the rest of the population to efficient treatments. The committee also considers that the efforts to prevent new infections must not be neglected and that individuals under successful treatment should not consider themselves as non infectious.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Protein phosphorylation and taurine biosynthesis in vivo and in vitro.

Taurine is known to be involved in many important physiological functions. Here we report that both in vivo and in vitro the taurine-synthesizing enzyme in the brain, namely cysteine sulfinic acid decarboxylase (CSAD), is activated when phosphorylated and inhibited when dephosphorylated. Furthermore, protein kinase C and protein phosphatase 2C have been identified as the enzymes responsible for phosphorylation and dephosphorylation of CSAD, respectively. In addition, the effect of neuronal depolarization on CSAD activity and 32P incorporation into CSAD in neuronal cultures is also included. A model to link neuronal excitation and CSAD activation by a Ca2+-dependent protein kinase is proposed.

Animals↗
PubMed1997

Expression of members of the novel membrane linked metalloproteinase family ADAM in cells derived from a range of haematological malignancies.

ADAMs (A disintegrin and metalloproteinase) are a recently discovered family of proteins with significant primary sequence similarity to the reprolysin family of snake venomases. These ADAMs closest known homologues are the type III reprolysin enzymes which have been demonstrated to be, among other things potent type IV collagenases. ADAMs are putative membrane linked proteins with several domains including a metalloproteinase domain, a potential integrin binding domain, a cysteine rich sequence and an EGF like sequence. They have been implicated in a wide variety of functions including basement membrane degradation and cell-cell and cell-matrix interactions. We have used RT-PCR and Northern blotting to characterise the expression of members of this family in cells derived from a variety of haematological malignancies including leukaemia (HL60 and Jurkat), erythroleukaemia (K562), lymphoma (U937 and Cupillo) and myeloma (U266B1). We find clear expression of four members of this novel family of proteins but note differences in the expression levels of each member. The ADAMs known as MADM (ADAM10), MCMP (ADAM12, MDC9) and Metargidin (ADAM15) which all possess potentially active metalloproteinase domains are expressed in all these cell types to significant levels. The putative tumour suppressor gene MDC (ADAM11) is expressed at very low levels in all cells examined. As ADAMs may have both potential metalloproteinase activity and adhesive domains we wish to explore the role of these proteins with regard to pathophysiology of haematological malignancy such as egression of leukaemic cells from the bone marrow.

Blotting, Northern↗
PubMed1997

Cis-acting elements required for expression of the nonspecific cross-reacting antigen gene in colorectal carcinoma.

BACKGROUND & AIMS: The nonspecific cross-reacting antigen (NCA) is a cell adhesion molecule, and the messenger RNA for NCA is overexpressed in 92% of colorectal carcinomas. The aim of this study was to determine the cis-acting elements that may be responsible for the expression of NCA. METHODS: Deletion mutants of the 5' flanking sequence and first intron were ligated into chloramphenicol acetyltransferase expression vectors, transfected into Chinese hamster ovary (CHO), DiFi, and HT-29 human colorectal carcinoma cells, and BxPC-3 and MDAPanc-28 human pancreatic carcinoma cells. The amount of acetylated chloramphenicol was determined to show the presence and activity of cis-acting sequences. RESULTS: The 5' flanking sequence functions as a promoter in all of cell lines and contains negative regulatory and enhancer sequences. The minimal promoter is active in Chinese hamster ovary and HT-29, though not in MDAPanc-28 cells. The first intron contains a silencer capable of suppressing a heterologous promoter. CONCLUSIONS: The results show cis-acting sequences within and 5' to the NCA gene, which appear to play a role in the expression of this gene in malignant tissues. Some of these sequences function in a cell type-specific manner. Further studies of these elements may provide insight into the mechanisms of the abnormal growth patterns of malignant cells.

Animals↗
PubMed1996

Collaboration using Internet for the development of case-based teaching files: report of the Computer and Instrumentation Council Internet Focus Group.

UNLABELLED: The Internet and particularly the World-Wide-Web is becoming a useful tool for the nuclear medicine community. METHODS: The Computer and Instrumentation Council of the Society of Nuclear Medicine convened an Internet Focus group to discuss collaboration using the Internet. The prototype application considered was development of case-based teaching files using the World-Wide-Web. Teaching file cases (clinical history, images, description of findings and discussion) on World-Wide-Web servers at different institutions are integrated using the Internet. The user can navigate from case to case using point-and-click hypertext linking. RESULTS: The initial experience with collaboration has been encouraging. An etiquette to help foster collaboration has been proposed. Development of quality control mechanisms and introduction of peer review were identified as issues needing further work. CONCLUSION: The World-Wide-Web offers great potential for new forms of collaboration. There is, however, a need to learn how to make best use of this new resource.

Computer Communication Networks↗
PubMed1996

Multiple sclerosis: a protective or a pathogenic role for heat shock protein 60 in the central nervous system?

The stress proteins belonging to the heat shock protein 60 (hsp6O) family of molecular chaperones with known immunogenic properties are expressed at increased levels in a number of autoimmune conditions. Because previous studies from this laboratory suggested that hsp6O may be involved in the pathogenesis of the chronic multiple sclerosis (MS) plaque, we have examined autopsied central nervous system tissue from 10 cases of MS, ranging in clinical history from acute to chronic inactive. MS lesions ranged from acute, actively demyelinating and edematous, to fibrous astrogliotic and chronically demyelinated. As controls, central nervous system tissue from other neurologic diseases and nonneurologic conditions was used. Frozen, paraffin, and epoxy-embedded sections were studied immunocytochemically with the ML30 mAb to hsp6O. Acute MS lesions displayed the greatest reactivity, with particularly prominent staining of hypertrophic astrocytes, reactive macrophages, and hyperplastic oligodendrocytes. In all these cells, elevated expression occurred in the constitutive site for hsp6O (mitochondria) and within the cytosol, which is suggestive of a shift in expression. The hsp6O-reactive oligodendrocytes were structurally intact. Chronic active MS lesions also revealed the highest levels of hsp6O in hypertrophic astrocytes and oligodendrocytes. Chronic silent MS lesions displayed elevated hsp6O in hypertrophic astrocytes only while constitutive expression occurred elsewhere in the central nervous system at levels slightly higher than normal. Other neurologic disease tissue displayed expression elevated above that found in nonneurologic cases, but this was considerably less than that seen in acute MS. Of the other neurologic diseases, AIDS encephalitis revealed the greatest activity for hsp6O, with both mitochondrial and cytosolic staining of astrocytes. It is proposed that the high levels of hsp6O in hyperplastic, structurally intact oligodendrocytes in acute MS lesions may bespeak a protective mechanism, whereas hsp6O in chronic active lesions may serve a pathogenic role in the later depletion of these cells.

Acute Disease↗
PubMed1996

[Pericardial devascularization in the treatment of portal hypertension with Larjet's innervation].

From 1982, 48 cases of portal hypertension were treated by pericardral devascularization with Larjet's innervation. Results were compared with that without preserving the Larjet's nerve in 57 cases. The incidence of rebleeding, mortality, abdominal distension, diarrhea, and gastric retension was 2%, 6.3%, 6.3%, 4.2%, and 0%, respectively in the former; and 12.5%, 12.3%, 24.6%, 15.6%, and 14%, respectively in the later. The authors believe that gastric function remained normal postoperatively when the Larjet's innervation was preserved.

Adult↗
PubMed1995

Elastic properties of osteoporotic bone measured by scanning acoustic microscopy.

A combination of low bone mass and decreased bone quality underlies osteoporotic fracture. We used scanning acoustic microscopy, a nondestructive method for assessing bone elasticity at a resolution of about 60 microns, to estimate the quality of biopsied iliac bones. We compared the acoustic velocities and bone volumes among premenopausal normal (n = 10), osteoporotic (n = 20), and postmenopausal normal (n = 10) subjects, the latter age-matched to the osteoporotic subjects. The acoustic measurements were highly reproducible (coefficient of variation = 0.32%). Bone volume of osteoporotic subjects (BV/TV = 13.3%) was lower than that of premenopausal and age-matched normals (BV/TV = 22.8%, p = 0.0007; BV/TV = 24.8%, p = 0.0004, respectively). Acoustic velocity of osteoporotic bone was 6.2% lower than that of age-matched normal bone (p < 0.02), but 3.4% higher than that of bone from premenopausal normal women. The lower acoustic velocity of osteoporotic bone than that of age-matched normal subjects implies that osteoporosis involves altered tissue elasticity. However, the lowest acoustic velocities were measured in premenopausal normal subjects. This unexpected result may indicate a complex relationship between tissue level properties and fragility in bone.

Aged↗
PubMed1995

Cross-species complementation of the indispensable Escherichia coli era gene highlights amino acid regions essential for activity.

Era is an essential GTP binding protein in Escherichia coli. Two homologs of this protein, Sgp from Streptococcus mutans and Era from Coxiella burnetii, can substitute for the essential function of Era in E. coli. Site-specific and randomly generated Era mutants which may indicate regions of the protein that are of functional importance are described.

Amino Acid Sequence↗
PubMed1995

Experimental renal artery stenosis and angioplasty. The mechanism of the angioplasty.

The mechanism of percutaneous transluminal renal angioplasty (PTRA) was studied in 18 dogs. The dogs were divided into two groups. Seven dogs were in the early group and eleven were within 1-3 weeks after PTRA. A 4/0 resorbable chronic catgut was used to ligate subtotally the renal artery to create fibromuscular dysplasia. PTRA was performed after renal artery stenosis for 6-8 weeks. The changes of ultrastructure of renal artery were studied. A contrary orientation balance hypothesis was proposed to explain the mechanism of PTRA.

Angioplasty, Balloon↗
PubMed1993

Collagen types I and III at the implant/tissue interface.

Collagen composition in tissue capsules around implants has been reported to differ histologically from collagen in subcutaneous connective tissue. In the present study, an immune histochemical analysis of collagen types I and III was undertaken in tissue capsules of various implant materials. The materials included polyvinyl chloride/polyacrylonitrile copolymer, poly(ethylene terephthalate), polysiloxane, titanium, and hydroxyapatite, which had been implanted into the dorsal subcutaneous space of rabbits for various time periods from 28 and to 90 days. The results indicate that collagen type III stained in all capsules independent of the evaluated materials, implantation periods, and material surface roughness. Collagen type I stained only in titanium implant capsules and dominated there over collagen type III. The staining sensitivity was highly specific and reproducible. The presence of collagen type III can be expected because it is the collagen of connective tissue healing. Collagen type I appears to be a response to chemical or electrochemical titanium surface properties but not to surface roughness. The quantitative relationship between the two collagen types may indicate capsule tissue stability and therefore serve as another biocompatibility measure.

Animals↗
PubMed1993

Neuroaxonal dystrophy in HTLV-1-associated myelopathy/tropical spastic paraparesis: neuropathologic and neuroimmunologic correlations.

Detailed neuropathologic and immunohistologic analysis of a case of serologically and polymerase chain reaction-confirmed human immunodeficiency virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is reported in a 73-year-old North American black woman. In addition to the usual neuropathologic features of HAM/TSP, including tractal degeneration of the spinal cord, leptomeningeal and perivascular fibrosis, perivascular demyelination and chronic inflammation, neuroaxonal spheroids were prominent in the spinal cord. Neuroaxonal dystrophy was characterized by neurofilamentous masses that were immunoreactive for phosphorylated neurofilament epitopes, but not ubiquitin. Neuroimmunologic analysis of the inflammatory reaction revealed a prevalence of CD8+ T cells and class I major histocompatibility molecules (MHC) (HLA-ABC and beta 2-microglobulin), but very few CD4+ T cells. Microglia were highly reactive for class II MHC (HLA-DR alpha) and this was attributed to activation, rather than CD4 interaction, since CD4 presence was minimal. Inflammatory cytokine immunoreactivity was also detected in glia. It is concluded that the cumulative effects of cytotoxic T cell (CD8) infiltration and the possible involvement of cytokines were responsible for the unusual degree of neuroaxonal dystrophy and vascular fibrosis, as well as the observed demyelination in this case.

Aged↗
PubMed1993

SP-40,40 immunoreactivity in inflammatory CNS lesions displaying astrocyte/oligodendrocyte interactions.

Immunoreactivity for SP-40,40, a putative complement inhibitor, adhesion or protective molecule, has been examined in a variety of inflammatory CNS lesions that displayed associations between hypertrophic astrocytes and oligodendrocytes, a phenomenon previously suggested to be related to oligodendrocyte phagocytosis or protection. SP-40,40 staining was common and was predominantly limited to hypertrophic astrocytes within lesion areas and diminished beyond the lesion margin. However, there was no consistent relationship between SP-40,40 immunoreactivity and astrocytes associated with oligodendrocytes. Staining for terminal complement complex (C5b-9/SC5b-9) occurred in association with larger vessel walls and microglial cells in the most active lesions, but was never seen in hypertrophic astrocytes. No association between SP-40,40 and complement deposition could be demonstrated. Staining for tumor necrosis factor-alpha showed a few scattered hypertrophic astrocytes to be positive. The findings confirm the presence of these astrocyte/oligodendrocyte interactions in active CNS lesions of varied etiology (multiple sclerosis, stroke and AIDS encephalitis). SP-40,40 immunoreactivity was common to hypertrophic astrocytes regardless of their associations with oligodendrocytes but showed no colocalization with terminal complement complex. Thus, these glial interactions do not apparently involve protection against complement-mediated lysis. Furthermore, the presence of SP-40,40 in astrocytes lacking association with oligodendrocytes did not support a role for this protein functioning as an adhesion molecule in astrocyte/oligodendrocyte associations.

AIDS Dementia Complex↗