Biomedical subjects

M Fu

Publications and source records attributed to M Fu.

At least 73 records · Page 4Linked to original sources

PubMed2000

Extensive dissection to the right sinus of Valsalva in coronary angioplasty: case report.

Percutaneous transluminal coronary angioplasty was first introduced in 1977 by Gruentzig and now provides the option of nonsurgical revascularization for up to 1/2 of patients who undergo diagnostic catheterization for coronary artery disease. Today, although there have been great improvements in technology and operator experience, complications still occur during coronary angiography and revascularization. Coronary dissection, one of the most frequently occurring complications during angiography and angioplasty, occurs in various forms. However, right coronary dissection and retrograde extension to the aortic sinus of Valsalva is extremely unusual during an interventional procedure. We report such an unusual complication which occurred during balloon angioplasty and which was successfully managed by coronary stenting. This unusual complication may have potential risk of quickly involving the entire aorta, causing acute severe aortic regurgitation, acute myocardial infarction, requiring emergency surgery, and even resulting in death. Therefore, prompt diagnosis and management of this complication are very important.

Angioplasty, Balloon, Coronary↗

PubMed2000

Ischaemic myelopathy presenting as Guillain-Barré syndrome.

Spinal cord stroke is uncommon. We report a woman presenting with paraesthesia followed by tetraparesis and respiratory failure who was initially diagnosed as having Guillain-Barré syndrome. Subsequent clinical and imaging features supported the diagnosis of an anterior spinal cord infarction. We describe the main clinical and imaging features of this condition.

Adult↗

PubMed2000

Rationale for directional atherectomy and adjunctive stenting in a patient with non-Q wave myocardial infarction.

The development of percutaneous transluminal balloon angioplasty (PTCA) is the greatest revolution in the management of stenotic coronary artery disease. However, PTCA is limited in its application to some specific subgroups of complex lesions such as bifurcational, ostial and plaque burden lesions. For this reason, some new strategies including directional atherectomy (DCA) have been developed as advanced modalities in the treatment of these complex lesions, which if treated by PTCA would certainly yield poor outcomes. We report a case of non-Q wave myocardial infarction resulting from obstruction of the ostium of left anterior descending artery. DCA and adjunctive stenting to the lesion were successfully performed and the patient was discharged uneventfully after the procedure. We suggest that DCA is a striking method and has much merit in the treatment of complex lesions with a high rate of success. In view of consideration of restenosis remains an importantly unresolved problem in percutaneous coronary intervention in specific subgroups of complex lesions. In the future, adequate debulking by mean of DCA in combination with adjunctive stenting which recently emerges as a promising treatment in the prevention of restenosis may provide a more consistent and attractive method for prevention of restenosis in these complex lesions.

Aged↗

PubMed2000

The practice of evidence-based medicine in an acute medical ward: retrospective study.

OBJECTIVE: To review the practice of evidence-based medicine with respect to drug treatment given to medical in-patients. DESIGN: Retrospective study. SETTING: Teaching hospital, Hong Kong. PATIENTS: Medical records of 129 consecutive patients who were admitted to the acute adult general medical ward from 1 September 1998 to 30 September 1998 were reviewed. MAIN OUTCOME MEASURES: Primary diagnoses, drug treatments prescribed, and the level of evidence (based on a literature search of randomised controlled trials and relevant studies) that supported the treatment given. RESULTS: For the 129 patients studied, 91 drug interventions had been prescribed on 312 occasions. Treatment that was supported by randomised controlled trials was prescribed in 162 (52.9%) cases. In 121 (38.8%) cases, patients were given standard and commonly used drugs that were not supported by evidence from clinical trials, and in 29 (9.3%) cases, the treatments given had no substantial supporting evidence. The management of some frequently encountered medical conditions was not based on trial data, because the relevant studies had not been conducted. CONCLUSION: Basing treatment on comparative efficacy results is a worthwhile goal, but there are limitations in conducting literature searches to identify relevant trials and studies. Evidence-based medical practice is not applicable in a large number of commonly encountered conditions.

Adult↗

PubMed2000

Three-dimensional echocardiographic image of atrial septal aneurysm: report of two cases.

Atrial septal aneurysm (ASA) is a rare congenital anomaly. It may occur as an isolated pathology or in association with other cardiovascular lesions such as mitral valve disease, atrial septal defect, and others. The diagnosis of ASA became more widely recognized with the use of 2-dimensional echocardiography. Three-dimensional echocardiography is a recently developed imaging technique. It can be used as an adjunct to conventional transesophageal echocardiography. Images of different aspects of cardiac chambers and valves can be obtained with 3-dimensional echocardiography. This paper reports on 2 cases of different types of ASA imaged by 3-dimensional echocardiography. The images were obtained from the left and right atriums, respectively. The 3-dimensional image taken from the left atrium showed the ASA to be a localized concave structure, and the 3-dimensional image taken from the right atrium showed the ASA to be a localized bulging structure. Our pictures are the first reported 3-dimensional echocardiographic images of ASA. We hope this report will allow for a more comprehensive understanding of its pathology.

Aged↗

PubMed2000

Changes in genioglossus muscle activity in obstructive sleep apnea patients with and without snore guard.

OBJECTIVE: To study the effect of Snore Guard on the genioglossus (GG) muscle activity of obstructive sleep apnea (OSA) patients. MATERIALS AND METHODS: Fifteen male patients with mild to severe OSA were diagnosed by overnight polysomnographic studies, and were reexamined after using Snore Guard for 2-6 months. The difference in GG muscle activity was then compared. RESULTS: The overnight GG muscle activity decreased significantly with Snore Guard. The levels of GG muscle activity during awake quiet breath and obstructive sleep apnea were higher than in sleepstate quiet breath without Snore Guard, and significantly decreased with Snore Guard. The increase in GG muscle activity during sleepstate quiet breath with Snore Guard was not statistically significant. The fluctuating GG muscle activity without Snore Guard was effectively improved by treatment with the appliance. CONCLUSION: The effect of Snore Guard on OSA patients is a mechanical enlargement of upper airway volume. The genioglossus muscle is passive during treatment.

Adult↗

PubMed2000

Analysis of the mandibular position in malocclusion patients.

OBJECTIVE: To study the changes of condyle position and occlusion between centric jaw relation (CR) and maximum intercuspation (MI) positions. METHODS: The power centric registration advocated by Roth was used to take centric relation bite registration for 50 patients (25 Angle Class I, and 25 Angle Class II). Diagnostic models were mounted and analyzed with Panadent articulator and condylar position indicator. RESULTS: Nearly all patients had CR-MI difference in all three spatial planes. Seventy percent of the sagittal displacement was within 2.0 mm and 87% of the transverse displacement was within 1.0 mm. Movement of most of the condyles was posterior and inferior. Sixty-five percent of the initial contacts in CR occurred on the most posterior molar on one side. When the mandible moved from CR to MI, overbite deepened, overjet decreased, and molar relationship became mesialized. Correlation was found between some variables of condylar displacement and occlusion changes. No significant difference between Angle Class I and Angle Class II patients was observed in condylar position and occlusion changes. CONCLUSION: The occlusion in centric jaw relation should be analyzed before treatment to reveal the disharmony between occlusion and jaw position.

Adolescent↗

PubMed2000

Overexpression of Bcl-2 partly inhibits apoptosis of human cervical cancer SiHa cells induced by arsenic trioxide.

OBJECTIVE: To study the biological effect of arsenic trioxide (As2O3) on human cervical cancer SiHa cells and SiHa cells overexpressing bcl-2 gene. METHODS: SiHa cells with overexpression of Bcl-2 (SiHa-Bcl2 cells) were established by transfecting SiHa cells with Bcl-2 expression vector. The sensitivities of SiHa and SiHa-Bcl2 cells to As2O3 were determined using MTT (Thiazolyl blue) reduction and colony forming ability assay, morphological analysis, flow cytometric analysis, DNA agarose gel electrophoresis, in situ cell death detection (TUNEL), Northern blot, RT-PCR and Western blot. RESULTS: As2O3 inhibited the growth of SiHa cells and induced G2/M arrest and apoptosis of the cells. RT-PCR and Western blot analysis revealed that As2O3 induced SiHa cell apoptosis possibly via inhibiting the expression of HPV16 E7 and decreasing the expression of c-myc. However, we found that SiHa-Bcl2 cells partly resisted As2O3 induced apoptosis, which might be related to the prevention of the down-regulation of HPV16 E7 and c-myc gene expression. Nevertheless, As2O3 at a high concentration could still induce apoptosis of SiHa-Bcl2 cells mainly via decreasing Bcl-2 expression and slightly inhibiting viral gene expression. CONCLUSION: As2O3 is an inducer of the apoptosis of human cervical carcinoma cells and the cells overexpressing Bcl-2 can partly resist As2O3 induced apoptosis, but the exact mechanism is unclear.

Antineoplastic Agents↗

PubMed2000

[Shear bond strength of glass ionomer cement for orthodontic bracket bonding].

OBJECTIVE: The purpose of this study was to investigate the shear bond strength of resin-modified glass ionomer used for orthodontic bracket bonding. METHODS: 30 extracted premolars were evenly divided into two groups. Edgewise brackets (Orsu) were bonded with resin-modified glass ionomer (Advance) in group one and with composite resin (DM) in group two. The shear bond strengths of two materials were tested by material testing machine after 24 hours. The adhesive remnant index was scored after debonding. RESULTS: The shear bong strengths of resin-modified glass ionomer and composite resin were (6.862 +/- 2.142) MPa and (7.183 +/- 3.205) MPa respectively. There were no statistically significant differences between two groups. CONCLUSIONS: In vitro bond strength of resin-modified glass ionomer had reached the same level of composite resin. It had the prospect of clinic use.

Composite Resins↗

PubMed2000

[Expression of transforming growth factor-beta 1 mRNA and osteopontin mRNA in UMR-106 cells under mechanical stimulation].

OBJECTIVE: To investigate the effects of the mechanical stretching on the expression of osteopontin (OPN) mRNA and transforming growth factor-beta 1 (TGF beta 1) mRNA in a rat osteosarcoma cell line (UMR-106), and to unveil the cellular mechanism of mechanical force-induced bone remodeling. METHODS: An apparatus was designed and fabricated by which force was loaded onto the cultured cells in vitro. Digoxin-labeled cDNA probes were used for in situ hybridization in combination with image analysis technique to relatively quantify the intensities of the hybridization signals. RESULTS: Various magnitudes and durations of the mechanical stretching did exert different influences on the intensities of the mRNAs' expression. Of all the combinations, the low tension/frequency group showed the most remarkable alteration of TGF-beta 1, as increased from 0.0899 to 0.1756 (P < 0.01). Some putative relations lay between the expressions of the OPN mRNA and the TGF-beta 1 mRNA. CONCLUSION: The mechanical stretching can inevitably influence the expression of OPN mRNA and TGF-beta 1 mRNA. The beneficial alteration obtained in using low tension/frequency action mode suggests and verifies the use of relatively constant and light force to move teeth in clinical orthodontics.

Animals↗

PubMed2000

[The detection and analysis of human papillomavirus in infantile respiratory tract papillomas by PCR/RFLP study].

OBJECTIVE: To study the relationship between human papillomavirus (HPV) and pathological characteristics of the patients with infantile respiratory tract papillomas (IRP). METHOD: Thirteen cases of infantile respiratory tract papillomas tissue were analysed for Papillomavirus by the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). RESULT: The amplified products of the HPV-L1 region by PCR by using the consensus primers showed that the presence of HPV was 100 percent. Eight cases(61.5 percent) were positive for HPV6 only. Four cases (30.8 percent) were positive for HPV11 only. One case (7.7 percent) showed the presence of HPV18. None were positive for HPV16, 31, 33, 52, 58. CONCLUSION: Infantile respiratory tract papillomas are associated with HPV6, 11, 18 infection, but the subtypes of HPV are not associated with clinical pathological characteristics.

Child, Preschool↗

PubMed1999

Activation of the cyclin D1 gene by the E1A-associated protein p300 through AP-1 inhibits cellular apoptosis.

The adenovirus E1A protein interferes with regulators of apoptosis and growth by physically interacting with cell cycle regulatory proteins including the retinoblastoma tumor suppressor protein and the coactivator proteins p300/CBP (where CBP is the CREB-binding protein). The p300/CBP proteins occupy a pivotal role in regulating mitogenic signaling and apoptosis. The mechanisms by which cell cycle control genes are directly regulated by p300 remain to be determined. The cyclin D1 gene, which is overexpressed in many different tumor types, encodes a regulatory subunit of a holoenzyme that phosphorylates and inactivates PRB. In the present study E1A12S inhibited the cyclin D1 promoter via the amino-terminal p300/CBP binding domain in human choriocarcinoma JEG-3 cells. p300 induced cyclin D1 protein abundance, and p300, but not CBP, induced the cyclin D1 promoter. cyclin D1 or p300 overexpression inhibited apoptosis in JEG-3 cells. The CH3 region of p300, which was required for induction of cyclin D1, was also required for the inhibition of apoptosis. p300 activated the cyclin D1 promoter through an activator protein-1 (AP-1) site at -954 and was identified within a DNA-bound complex with c-Jun at the AP-1 site. Apoptosis rates of embryonic fibroblasts derived from mice homozygously deleted of the cyclin D1 gene (cyclin D1(-/-)) were increased compared with wild type control on several distinct matrices. p300 inhibited apoptosis in cyclin D1(+/+) fibroblasts but increased apoptosis in cyclin D1(-/-) cells. The anti-apoptotic function of cyclin D1, demonstrated by sub-G(1) analysis and annexin V staining, may contribute to its cellular transforming and cooperative oncogenic properties.

Adenovirus E1A Proteins↗

PubMed1999

Integration of Rac-dependent regulation of cyclin D1 transcription through a nuclear factor-kappaB-dependent pathway.

The small GTP-binding protein Rac1, a member of the Ras superfamily, plays a fundamental role in cytoskeleton reorganization, cellular transformation, the induction of DNA synthesis, and superoxide production. Cyclin D1 abundance is rate-limiting in normal G(1) phase progression, and the abundance of cyclin D1 is induced by activating mutations of both Ras and Rac1. Nuclear factor-kappaB (NF-kappaB) proteins consist of cytoplasmic hetero- or homodimeric Rel-related proteins complexed to a member of the IkappaB family of inhibitor proteins. In the current studies, activating mutants of Rac1 (Rac(Leu-61), Rac(Val-12)) induced cyclin D1 expression and the cyclin D1 promoter in NIH 3T3 cells. Induction of cyclin D1 by Rac1 required both an NF-kappaB and an ATF-2 binding site. Inhibiting NF-kappaB by overexpression of an NF-kappaB trans-dominant inhibitor (nonphosphorylatable IkappaBalpha) reduced cyclin D1 promoter activation by the Rac1 mutants, placing NF-kappaB in a pathway of Rac1 activation of cyclin D1. Specific amino acid mutations in the amino-terminal effector domain of Rac(Leu-61) had comparable effects on NF-kappaB transcriptional activity and activation of the cyclin D1 promoter. The NF-kappaB factors Rel A (p65) and NF-kappaB(1) (p50) induced the cyclin D1 promoter, requiring both the NF-kappaB binding site and the ATF-2 site. Stable overexpression of Rac(Leu-61) increased binding of Rel A and NF-kappaB(1) to the cyclin D1 promoter NF-kappaB site. Activation of Rac1 in NIH 3T3 cells induces both NF-kappaB binding and activity and enhances expression of cyclin D1 through an NF-kappaB and ATF-2 site in the proximal promoter, suggesting a critical role for NF-kappaB in cell cycle regulation through cyclin D1 and Rac1.

3T3 Cells↗

PubMed1999

Arsenic trioxide induces apoptosis of HPV16 DNA-immortalized human cervical epithelial cells and selectively inhibits viral gene expression.

Arsenic trioxide (As2O3), a major ingredient of arsenic compounds in traditional Chinese medicine, exhibits anti-acute promyelocytic leukemic activity. Considering that over 80% of human malignant tumors derive from epithelial cells, we studied the effect of As2O3 on HPV 16 DNA-immortalized human cervical epithelial cells (HCE16/3 cells) in vitro. As2O3 reduced HCE16/3 cell survival, induced apoptosis at a low concentration and selectively inhibited expression of viral early genes. This effect was evidenced by a reduction of cell viability in the MTT assay, G1 arrest and significant apoptosis upon flow-cytometric analysis, presence of apoptotic bodies, formation of DNA ladders upon gel electrophoresis and inhibition of viral early gene expression by RT-PCR and Western blot. There was a good correlation between cell apoptosis and viral early gene inhibition after As2O3 treatment, suggesting that induction of apoptosis of HCE16/3 cells by As2O3 treatment might be associated with down-regulation of viral oncogene expression. In conclusion, our findings indicate that As2O3 induces apoptosis of HCE16/3 cells, which may provide a new approach for treating HPV-associated tumors.

Antineoplastic Agents↗

PubMed1999

Receptor recruitment: a mechanism for interactions between G protein-coupled receptors.

There is a great deal of evidence for synergistic interactions between G protein-coupled signal transduction pathways in various tissues. As two specific examples, the potent effects of the biogenic amines norepinephrine and dopamine on sodium transporters and natriuresis can be modulated by neuropeptide Y and atrial natriuretic peptide, respectively. Here, we report, using a renal epithelial cell line, that both types of modulation involve recruitment of receptors from the interior of the cell to the plasma membrane. The results indicate that recruitment of G protein-coupled receptors may be a ubiquitous mechanism for receptor sensitization and may play a role in the modulation of signal transduction comparable to that of the well established phenomenon of receptor endocytosis and desensitization.

Adrenergic alpha-Agonists↗

PubMed1999

Short- and long-term outcomes after percutaneous transluminal coronary angioplasty in chronic hemodialysis patients.

The aim of this study was to obtain data on the outcomes of chronic hemodialysis patients who underwent percutaneous transluminal coronary angioplasty (PTCA). A retrospective chart analysis identified 31 such patients between August 1992 and October 1996. The mean follow-up period was 12.4 +/- 11.7 months. Angiographic success was achieved in 39 of 41 (95.1%) stenoses attempted. There were three in-hospital deaths. Clinical success was achieved in 28 of 31 patients (90%). Two of the 28 survivors were lost to follow-up. Recurrent angina developed within 6 months in 14 of 26 patients (53.8%). Eleven and 17 of the 26 patients (42.3% and 65.4%) died within 6 and 14 months, respectively, after the PTCA procedure. Ten of the 17 deaths (58.8%) were due to cardiovascular events. Our study suggests that PTCA is technically feasible with high angiographic success rate in chronic hemodialysis patients. In-hospital mortality rate and rate of recurrent angina are high. Long-term prognosis is poor.

Aged↗

PubMed1999

Fish oil decreases macrophage tumor necrosis factor gene transcription by altering the NF kappa B activity.

BACKGROUND: Fish oil-supplemented diets have anti-inflammatory and immunomodulating effects, though the exact mechanism(s) are unknown. This study investigated the effects of eicosapentanenoic acid (EPA), a major component of fish oil, on transcriptional regulation of tumor necrosis factor (TNF) gene in lipopolysaccharide (LPS)-stimulated macrophages (MO). METHODS: RAW 264.7 cells, a mouse MO cell line, were grown in EPA-rich media for 24-48 h. MO were washed and exposed to Escherichia coli LPS (1 microg/ml) for 2 h. TNF mRNA expression was measured by Northern blot assays. Total nuclear extracts were harvested for the measurement of NF kappa B with electrophoretic mobility shift assays. Supershift assays were performed with anti-P50 or anti-P65 antibodies to show components of NF kappa B dimers. TNF production was determined by L929 bioassays. RESULTS: LPS stimulated RAW cell TNF mRNA expression and NF kappa B activity. In contrast, RAW cells grown in EPA-rich media had less TNF mRNA expression and an altered composition of the NF kappa B subunits (P65/P50 dimers) in the presence of LPS. TNF production by LPS-stimulated MO was reduced by EPA. CONCLUSIONS: The inhibitory effect of EPA on LPS-stimulated MO TNF gene transcription and protein elaboration is, in part, mediated through altering NF kappa B activation by reducing the P65/P50 dimers.

Animals↗

PubMed1999

Fish oil augments macrophage cyclooxygenase II (COX-2) gene expression induced by endotoxin.

BACKGROUND: Fish oil-supplemented diets have anti-inflammatory and immunomodulating effects. Although fish oil is readily incorporated into the cell membrane and influences the production of eicosanoids, the exact mechanism is not clear. This study was designed to investigate the effects of eicosapentaenoic acid (EPA), a major component of fish oil, on macrophage (Mphi) cyclooxygenase (COX) gene expression induced by LPS. METHODS: RAW 264.7 cells, a mouse Mphi cell line, were grown in EPA-rich media for 24 h. Mphi were washed and exposed to Escherichia coli LPS (10 microg/ml). Membrane lipid profile was determined by gas chromatographic analysis. COX-1 and COX-2 mRNA expressions were determined by Northern blot assays with mouse-specific cDNA probes. PGE(2) production of Mphi was measured by ELISA. Mphi production of COX-2 protein was determined by Western blot assays with an anti-COX-2 antibody. RESULTS: Incubation in EPA-rich media increased membrane EPA and decreased arachidonic acid (AA) composition. COX-2 mRNA expression was induced by EPA and further augmented by LPS stimulation. EPA also augmented Mphi production of COX-2 protein. In comparison, COX-1 mRNA expression was not affected by either LPS stimulation or EPA incubation. EPA reduced PGE(2) production by LPS-stimulated Mphi. To further support that COX-2 mRNA was regulated by COX product, exogenous PGE(2) was added to Mphi prior to LPS stimulation. PGE(2) reduced COX-2 mRNA of LPS-stimulated Mphi. CONCLUSION: EPA displaces AA and reduces PGE(2) production by LPS-stimulated Mphi. Fish oil inhibition of Mphi PGE(2) production induces COX-2 mRNA expression through a COX-2 product-mediated feedback mechanism.

Animals↗