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Biomedical subjects

Y H Liu

Publications and source records attributed to Y H Liu.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Effect of peritoneal dialysis in elderly patients].

OBJECTIVE: To evaluate the effects of peritoneal dialysis in elderly patients. METHOD: One hundred and fifty-five patients were divided into two groups(elder-aged group > or = 60 years, 59 cases; medium aged group < 60 years, 96 cases). The changes of blood pressure, Hb and renal function between the two groups were compared after six months of peritoneal dialysis. The data were processed by SPSS 7.0 software. RESULTS: Primary disease analysis showed 47.4% hypertension and 28.8% diabetes in elder-aged group and 72.9% chronic glomerulonephritis in medium-aged group. The changes of Bp and Hb was not significant in both groups after dialysis. Renal function was improved in both groups. Concentration of total protein and albumin was decreased in elder-aged group and remained nearly unchanged in medium-aged group after dialysis. The survival rates of the two groups had no difference. CONCLUSION: As a simple, safe and effective method, peritoneal dialysis is especially suitable to elderly patients for continuous treatment.

Age Factors↗
PubMed2000

Extraction and characterization of adenovirus proteins from sodium dodecylsulfate polyacrylamide gel electrophoresis by matrix-assisted laser desorption/ionization mass spectrometry.

A new methodology for the extraction and characterization of proteins from Coomassie-stained sodium dodecylsulfate polyacrylamide gel electrophoresis using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been described. The utility of this methodology was demonstrated in the characterization of adenovirus proteins. The key steps in the extraction and destaining process involve washing the excised band with a combination of solvents that include 10% acetic acid, acetonitrile, methanol, and formic acid:water:isopropanol mixture. By using this procedure, we determined adenovirus proteins with molecular weights ranging from 10,000 to 110,000 Da by MALDI-MS, obtaining a detection limit of approximately 6 pmol. Parallel experiments were successfully carried out to analyze adenovirus proteins from Cu-stained gels. It was observed that increase in laser intensity resulted in significant improvements in the quality of MALDI mass spectra for the analysis of inefficiently destained proteins from Cu-stained gels.

Adenoviridae↗
PubMed2000

Bioavailability of iron from purple laver (Porphyra spp.) estimated in a rat hemoglobin regeneration bioassay.

Laver belongs to the genius of Porphyra and is the most valuable seaweed in the aqua-culture industry. It contains higher iron than many other plant foods. The bioavailability of iron from laver was evaluated in a rat hemoglobin regeneration assay. Reagent-grade ferrous sulfate was used as the reference standard, and the relative biological value (RBV) for laver was expressed as a percentage of the response to ferrous sulfate. RBV was calculated by two methods: slope-ratio and ratio of hemoglobin regeneration efficiency, and both yielded RBV of 26 for laver. Amount of available iron from laver estimated from RBV was comparable to many iron-fortified foods.

Animals↗
PubMed2000

Effects of ellagic acid by oral administration on N-acetylation and metabolism of 2-aminofluorene in rat brain tissues.

Numerous studies have demonstrated that the Acetyl Coenzyme A-dependent arylamine NAT enzyme exist in many tissues of experimental animals including humans, and that NAT has been shown to be exist in mouse brain tissue. Increased NAT activity levels are associated with increased sensitivity to the mutagenic effects of arylamine carcinogens. Attenuation of liver NAT activity is related to breast and bladder cancer processes. Therefore, the effects of ellagic acid (EA) on the in vitro and in vivo N-acetylation of 2-aminofluorene (AF) were investigated in cerebrum, cerebellum and pineal gland tissues from male Sprague-Dawley rats. For in vitro examination, cytosols with or without EA (0.5-500 microM) co-treatment decreased 7-72%, 15-63% and 10-78% of AF acetylation for cerebrum, cerebellum and pineal gland tissues, respectively. For in vivo examination, EA and AF at the same time treated groups with all 3 examined tissues did show significant differences (the changes of total amounts of AF and AF metabolites based on the Anova analysis) when compared to the ones without EA cotreatment rats. The pretreatment of male rats with EA (10 mg/kg) 24 hr prior to the administration of AF (50 mg/kg) (one day of EA administration suffice to induce large changes in phase II enzyme activity) resulted in a 76% decrease in total AF and metabolites in pineal gland but did not show significant differences in cerebrum and cerebellum tissues. This is the first demonstration to show that EA decreases the N-acetylation of carcinogens in rat brain tissues.

Acetylation↗
PubMed2000

Conditional inactivation of Fgf4 reveals complexity of signalling during limb bud development.

Development of the vertebrate limb bud depends on reciprocal interactions between the zone of polarizing activity (ZPA) and the apical ectodermal ridge (AER). Sonic hedgehog (SHH) and fibroblast growth factors (FGFs) are key signalling molecules produced in the ZPA and AER, respectively. Experiments in chicks suggested that SHH expression in the ZPA is maintained by FGF4 expression in the AER, and vice versa, providing a molecular mechanism for coordinating the activities of these two signalling centres. This SHH/FGF4 feedback loop model is supported by genetic evidence showing that Fgf4 expression is not maintained in Shh-/- mouse limbs. We report here that Shh expression is maintained and limb formation is normal when Fgf4 is inactivated in mouse limbs, thus contradicting the model. We also found that maintenance of Fgf9 and Fgf17 expression is dependent on Shh, whereas Fgf8 expression is not. We discuss a model in which no individual Fgf expressed in the AER (AER-Fgf) is solely necessary to maintain Shh expression, but, instead, the combined activities of two or more AER-Fgfs function in a positive feedback loop with Shh to control limb development.

Animals↗
PubMed2000

Thoracoscopic removal of intrathoracic neurogenic tumors: a combined Chinese experience.

OBJECTIVE: To review the surgical and clinical results of minimally invasive resection of intrathoracic neurogenic tumors using a video-assisted thoracoscopic technique. SUMMARY BACKGROUND DATA: Thoracoscopy has emerged as a possible means for diagnosing and managing various intrathoracic disorders. Benign intrathoracic tumors often are ideal lesions for resection using a video-assisted technique. The authors report on their combined experience with the thoracoscopic resection of 143 intrathoracic neurogenic tumors. METHODS: Between March 1992 and February 1999, 143 patients with intrathoracic neurogenic tumors were diagnosed and underwent resection using video-assisted thoracoscopic techniques in three teaching centers. Case selection, surgical technique, and clinical results were reviewed. RESULTS: The average age of the patients was 40.8 years; 57.3% were male. Thirty-eight patients (27%) had symptoms attributable to the masses. Seventy-two masses were neurofibromas, 33 were neurilemmomas, 7 were paragangliomas, and 31 were ganglioneuromas. All but seven tumors were located in the posterior mediastinum. The masses were on average 3.5 cm in greatest diameter. The mean surgical time was 40 minutes, and the average hospital stay was 4.1 days. There were no major postoperative complications or recurrences to date. Nine patients reported paresthesias over the chest wall during a mean follow-up of 29 months. CONCLUSIONS: Resection of intrathoracic neurogenic tumors using a thoracoscopic technique based on standard surgical indications would seem to be appropriate. Most of these masses are benign and readily removed. For dumbbell tumors, a combined thoracic and neurosurgical approach is mandatory.

Adult↗
PubMed2000

Effects of ACE inhibitor, AT1 antagonist, and combined treatment in mice with heart failure.

We tested the hypothesis that a combination of angiotensin-converting enzyme inhibitor (ACEi) and angiotensin II type 1 receptor antagonist (AT1-ant) may have an additive cardioprotective effect in mice with heart failure (HF), because these two agents could have other mechanisms of action besides interrupting the renin-angiotensin system. ACEi prevent degradation of bradykinin. During treatment with AT1-ant, increased angiotensin II could activate AT2 receptors, with an antitrophic effect. To test this hypothesis, we used a mouse model of HF induced by myocardial infarction. Seven days after surgery, mice were divided into six groups and treated for 23 weeks: (a) sham ligation; (b) HF-vehicle; (c) HF-ACEi; (d) HF-AT1-ant; (e) HF-ACEi + AT1-ant (half dose of each); and (f) HF-ACEi + AT1-ant (full dose of each). Cardiac function was evaluated in conscious mice during the treatment period. The HF-vehicle group showed significantly decreased left ventricular (LV) ejection fraction (EF), shortening fraction (SF), and cardiac output (CO) and increased LV dimensions, interstitial collagen, and myocyte cross-sectional area (MCSA) compared with controls. Treatment with ACEi or AT1-ant significantly increased EF, SF, and CO and decreased LV dimensions and MCSA in mice with HF. However, a combination of these drugs did not improve cardiac function more than ACEi or AT1-ant alone. We concluded that ACEi and AT1-ant have similar cardioprotective effects and may reach maximal effect when given individually; thus no further improvement can be achieved with combined therapy in mice with HF.

Angiotensin I↗
PubMed2000

Role of kinins in chronic heart failure and in the therapeutic effect of ACE inhibitors in kininogen-deficient rats.

Using Brown Norway Katholiek (BNK) rats, which are deficient in kininogen (kinin precursor) due to a mutation in the kininogen gene, we examined the role of endogenous kinins in 1) normal cardiac function; 2) myocardial infarction (MI) caused by coronary artery ligation; 3) cardiac remodeling in the development of heart failure (HF) after MI; and 4) the cardioprotective effect of angiotensin-converting enzyme inhibitors (ACEI) on HF after MI. Two months after MI, rats were randomly treated with vehicle or the ACEI ramipril for 2 mo. Brown Norway rats (BN), which have normal kininogen, were used as controls. Left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), end-diastolic pressure (EDP), and ejection fraction (EF) as well as myocardial infarct size (IS), interstitial collagen fraction (ICF), cardiomyocyte cross-sectional area (MCA), and oxygen diffusion distance (ODD) were measured. We found that 1) cardiac hemodynamics, function, and histology were the same in sham-ligated BN and BNK rats; 2) IS was similar in BN and BNK; 3) in rats with HF treated with vehicle, the decrease in LVEF and the increase in LVEDV, LVESV, LVEDP, ICF, MCA, and ODD did not differ between BNK and BN; and 4) ACEI increased EF, decreased LVEDV and LVESV, and improved cardiac remodeling in BN-HF rats, and these effects were partially blocked by the bradykinin B(2) receptor antagonist icatibant (HOE-140). In BNK-HF rats, ACEI failed to produce these beneficial cardiac effects. We concluded that in rats, lack of kinins does not influence regulation of normal cardiac function, myocardial infarct size, or development of HF; however, kinins appear to play an important role in the cardioprotective effect of ACEI, since 1) this effect was significantly diminished in kininogen-deficient rats and 2) it was blocked by a B(2) kinin receptor antagonist in BN rats.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Biology of Diaphorina citri (Homoptera: Psyllidae) on four host plants.

The biology of the citrus psyllid Diaphorina citri Kuwayama was studied at 25 degrees C on four commonly grown citrus and related plants [rough lemon, Citrus jambhiri Lush; sour orange, C aurantium L.; grapefruit, C. paradisi Macfadyen; and orange jessamine, Murraya paniculata (L.) Jack] in the laboratory. The biological characteristics of each life stage are described. The average egg incubation periods on orange jessamine, grapefruit, rough lemon, and sour orange varied very little (4.1-4.2 d). The average nymphal developmental periods on these four host plants were essentially the same except the fifth stadium. Survival of immatures on orange jessamine, grapefruit, rough lemon, and sour orange was 75.4, 84.6, 78.3, and 68.6%, respectively. Female adults lived an average of 39.7, 39.7, 47.6, and 43.7 d on these respective host plants. The average number of eggs laid per female on grapefruit (858 eggs) was significantly more than those on other hosts (P < 0.05). The intrinsic rate of natural increase (r(m)) for D. citri on grapefruit was highest. Jackknife estimates of r(m) varied from 0.188 on grapefruit to 0.162 on orange jessamine and rough lemon. The mean population generation time on these hosts ranged from 31.6 to 34.1 d. The continuous flushes produced by orange jessamine could play an important role in maintaining high populations of this vector when the new flushes are not available in the commercial citrus groves.

Animals↗
PubMed2000

Validation of the Yale circumferential quantification method using 201Tl and 99mTc: a phantom study.

UNLABELLED: The Yale circumferential quantification (Yale CQ) method for quantification of SPECT images has been validated previously using empirically derived correction factors. In the present studies, the Yale CQ method was further validated using 2 SPECT gamma cameras and 2 radioisotopes. METHODS: SPECT images were acquired from cardiac phantoms with multiple fillable inserts to simulate myocardial perfusion defects of varying extents and severities. Seventy phantom configurations were created. One hundred and forty SPECT images (70 with 99mTc and 70 with 201TI) were acquired using a triple-head SPECT camera. SPECT defects were quantified using the Yale CQ method, with incorporation of 99mTc- and 201TI-derived normal databases and correction factors. RESULTS: Quantified phantom SPECT defect sizes acquired with 99mTc correlated well with actual calculated defect sizes (r = 0.96, y = 0.92x - 0.41). Bland-Altman analysis of agreement revealed strong agreement over a wide range of defect sizes, with a mean error of 1.2% and 2 SDs of 5.0%. Overall 201TI SPECT defect sizes also correlated well with actual defect sizes (r = 0.92), but there was a systematic underestimation (y = 0.72x - 0.76). Bland-Altman analysis showed underestimation over the entire range of defect sizes, with a mean error of 3.4% and 2 SDs of 7.5%. Implementation of a normal 201TI phantom database improved accuracy of quantification (r = 0.95, y = 0.87x - 1.36). The addition of 201TI-specific correction factors further improved accuracy (r= 0.94, y = 0.98x - 1.52). Reproducibility of SPECT defect sizes quantification for 99mTc using 2 gamma cameras was excellent (r = 0.98, y = 0.98x + 0.84). CONCLUSION: The Yale CQ SPECT quantification method, using the empirically derived correction factors, provides accurate and reproducible quantification of phantom defects over a wide range of defect sizes. Accurate quantification of 201TI and 99mTc SPECT defect sizes requires radiotracer-specific normal databases.

Gamma Cameras↗
PubMed2000

Cost-effective approach of video-assisted thoracic surgery: 7 years experience.

BACKGROUND: Cost containment is the driving force behind current health care reform. While video-assisted thoracic surgery (VATS) permits a less invasive approach to surgical diseases of the chest, cost is one aspect that is seldom discussed. In Asia, cost-effectiveness essential for the survival of this approach. We present our cost-effective experience with VATS in 2300 patients over a 7-year period. METHOD: Between 1992 and 1999, 2300 patients underwent video-assisted thoracic surgery at Chang Gung Memorial Hospital. The mean age was 53.2 years (range, 22 days to 102 years); 67% (1541 patients) were men. The VATS technique was mainly performed based on traditional surgical principles. Conventional instruments and the fundamental surgical techniques of dissection, suturing, hemostasis, and tissue approximation that are familiar in the open setting were modified and used to enhance cost savings during VATS. RESULTS: Surgery was performed on 41 patients on an emergency basis (24 with impending cardiac tamponade and 17 with hemothorax). The mean hospital stay of the patients treated by VATS was 4.5 days. The majority of the patients were operated on successfully using conventional instruments under video vision. The overall operative cost was decreased as compared to common VATS techniques. No delayed morbidity was noted in our patients after a mean follow-up period of 39 months (range, 1 to 68 months). CONCLUSION: It is our experience that VATS procedures should be performed with the same expertise as open surgery. Conventional instruments similar to those used in open thoracotomy can be incorporated in VATS, and with a more natural hand manipulation. Only through stringent use of expensive endoscopic consumables and application of modified techniques based on traditional surgical principles can VATS be performed efficaciously and economically for a wide range of thoracic conditions.

Adolescent↗
PubMed2000

Catamenial hemoptysis: report of a case treated with thoracoscopic wedge resection.

Catamenial hemoptysis is a rare form of hemoptysis. It is a term for the condition of hemoptysis associated with menses. Few cases have been reported in the literature. Only one case, treated by video-assisted thoracoscopic wedge resection, has been described. We report the case of a 26-year-old woman who suffered from catamenial hemoptysis for 7 months and was treated successfully with a video-assisted thoracoscopic (VATS) wedge resection of the lesion. No evidence of recurrence was noted in the postoperative follow-up period of 48 months. We suggest that VATS is the good choice for single focus catamenial hemoptysis.

Adult↗
PubMed2000

Paradoxical cerebral air embolism after removal of a central venous catheter: case report.

Paradoxical cerebral air embolization through a residual tract after the removal of a central venous catheter is a serious complication of central venous cannulation. Air embolisms resulting from residual catheter tracts in general patients and in single lung transplant patients have been reported. The generally accepted mechanism of this complication is failure of a spontaneous collapse or thrombotic obliteration of a well-formed catheter tract. It may be related to the duration of catheter insertion, the patient's nutritional status, the diameter of the indwelling catheter, the upright position of the patient, deep inspiration or coughing, and improper wound dressing and catheter removal. Cardiovascular collapse, pulmonary or neurologic sequelae, and even death, are commonly noted in patients with air embolism. In this article, we report on cerebral air embolization as a complication with the removal with a central venous catheter in a patient with bullous emphysema. A high degree of suspicion and a prompt diagnosis are required for successful application of established therapy. Simple prophylactic procedures and constant awareness of the unusual mechanism of air embolism remain the best treatment.

Aged↗
PubMed2000

Thoracoscopic retrieval of metal rods after penetrating chest injury: case report.

Thoracoscopy has been used for both diagnostic and therapeutic purposes. Its use in the trauma field is rapidly increasing. Here, we present a case of chest trauma that was successfully treated using the thoracoscopic approach. A 43-year-old male patient was brought to our emergency room with a severe right chest wall-penetrating metal-rod injury, which had occurred after falling from a height. The chest X-ray showed an upper right lung lobe injury. Video-assisted thoracoscopic surgery (VATS) was performed for diagnosis of any other associated injury and for management of the penetrating injury. The prognosis was good. We believe that minimal thoracoscopic surgery is an alternative way that provides a more rapid diagnosis, and a less-invasive and safe operation for acute chest trauma patients.

Adult↗