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Biomedical subjects

Y F Yu

Publications and source records attributed to Y F Yu.

13 recordsLinked to original sources
PubMed1992

Determination of plutonium-239 + plutonium-240 and plutonium-241 in environmental samples using low-level liquid scintillation spectrometry.

A radiochemical method for the simultaneous determination of 239Pu + 240Pu and 241Pu in environmental samples has been developed. In the course of the analysis a 236Pu tracer was used for estimating the chemical yield of plutonium isotopes. After suitable pre-treatment of the sample, the plutonium nuclides in solution were coprecipitated with iron(III) hydroxide and calcium oxalate and isolated further from impurities and interfering radionuclides by means of anion-exchange chromatography. Plutonium isotopes in the eluate (NH4I-HCI) were converted into nitrate form and then extracted with 20 ml of 5% bis(2-ethylhexyl) hydrogen phosphate extractive cocktail. The final organic solution was measured spectrometrically using an ultra-low-level liquid scintillation spectrometer, Quantulus (LKB, 1220 Wallac). The chemical yields of plutonium range from 25 to 50% for 100 I of sea-water and 30 to 60% for 40 g of dried soil sample. The counting efficiencies are nearly 100% for 239Pu + 240Pu and 48.8% for 241Pu, respectively. The detection limits were estimated to be 0.20 mBq for 239Pu + 240Pu and 2.2 mBq for 241Pu, respectively. The proposed procedure has been tested for the simultaneous determination of 239Pu + 240Pu and 241Pu in sea-water (Irish Sea, North Sea) and soils (Cumbrian coast, UK; Byelorussia, USSR).

Europe↗
PubMed1992

[Surgical treatment of mitral prolapse with chordae plasty].

Surgical treatment of 8 cases of anterior mitral leaflet prolapse was reported. Of the 8 cases, chordae elongation was occurred in 2, chordae rupture in 6, and congenital in 6, rheumatic in 2. Chordae reimplanting was performed in 5 cases, chordae shortening in 2, chordae prosthesis with surgical suture in 1, and combined annuloplasty in 7 of the 8 cases. The result of mitral plasty was better in congenital mitral prolapse. Indications of this technique and postoperative management were listed.

Adolescent↗
PubMed1992

[Re-open heart surgery in congenital heart disease. An analysis of 23 cases].

The authors reported 23 cases of re-open heart surgery in 1473 patients with congenital heart disease treated surgically in the last ten years. The incidence was 1.6%. In 13 cases of the 23 re-open heart procedure was performed before closing the chest during the operation because of missed diagnosis in 5, incomplete correction of the anomaly in 5, and injure to important organ in 3. All of the 13 patients were recovered and discharged. Of the 23 cases re-open heart surgery was performed during the early postoperative period in 8 cases, including 4 cases of misdiagnosis, and 4 incomplete correction. 1 patient with VSD had still residual ventricular septal shunt post reintervention and died of circulatory failure. Re-open heart surgery was performed during the late postoperative period in 2 of the 23 cases. There was 1 missed diagnosis, and another incomplete correction. 1 patient died of massive bleeding during the reoperation. The anthers pointed out that accurate diagnosis and error-free operation is of most importance in avoiding re-open heart surgery. Through exploration to the heart after resuscitation during the operation and positive re-opening of the heart when necessary were emphasized. Indication of early and late postoperative re-open heart surgery and methods to prevent its complication were listed.

Cardiopulmonary Bypass↗
PubMed1991

[Pathological analysis of renal osteodystrophy in 194 cases].

Renal osteodystrophy is a metabolic bone disease resulted from chronic renal failure. The long-standing alterations in a mineral metabolism generated by renal failure have a profound effect on the skeleton and induce severe systemic metabolic bone disease. Iliac crest biopsies of 194 patients of chronic renal failure were taken and among them 10 cases were examined for Calcium(Ca), phosphorus (p), parathyroid hormone (PTH), 1,25(OH)2D3 and aluminium (Al). The histological bone changes are characterized by development of osteitis fibrosa, increase of bone resorption and the number of osteoclast, increase of osteoid volume (osteoblastic osteoid and acellular osteoid), active remodelling of bone and aluminum deposition in the bone. According to histological appearance, advanced renal bone disease could be subdivided into three groups namely: Secondary hyperparathyroid bone disease (high turnover uremic osteodystrophy), osteomalacia (low turnover uremic osteodystrophy) and mixed uremic osteodystrophy consisting of mild to moderate hyperparathyroid bone disease and defective mineralization. Aluminum-related bone changes might be obtained in various extent in all these groups. Although this classification does not fully represent all the separated entities, and there is also transformation from one form to another, it seems no less significant as a reference for clinical considerations.

Adolescent↗
PubMed1991

[Fungal endocarditis after open-heart surgery. Report of 4 cases].

Four patients with fungal endocarditis after open-heart surgery were confirmed microbiologically. Two of them died, and the other 2 were treated with intravenous administration of miconazole. Clinical symptoms of the disease were similar to those of bacterial endocarditis, but headache and sweating were more predominant. This complication was likely to be found and treated with effective anti-fungi drugs. We suggest that reoperation is the only possible way to cure those with residual shunt or vegetation, and that prevention of postoperative fungal endocarditis is of great importance because of its refractoriness. Measures of preventing fungal endocarditis after open-heart surgery are discussed.

Adolescent↗
PubMed1990

Electronmicroscopic observation on chronic cardiopathy in spontaneous diabetic biobreeding rats.

The ultrastructural changes of chronic cardiopathy in diabetic biobreeding rats were observed electronmicroscopically. The thickness of the myocardial capillary basement membrane (CBM) and volume fraction of myofilaments in the myocardium were quantitatively measured with a video interactive display system III (VIDS-III). The effect of metabolic control on chronic diabetic cardiopathy was also investigated.

Actin Cytoskeleton↗
PubMed1990

[Ultrastructural studies on effects of colchicine in treating hepatic fibrosis of schistosomiasis rabbits].

8 rabbits were infected percutaneously with the cercariae of Schistosoma japonicum. After hepatic fibrosis had developed in these rabbits 4 months after infection, 4 out of the 8 infected rabbits were given colchicine orally at a dosage of 40 micrograms/kg per day for 7 weeks. Another uninfected rabbits were used as controls. The therapeutic effects of colchicine on hepatic fibrosis were studied by transmission electron microscopy and morphometry, in which the area of collagen microfibrils in the space of disse and liver cells was measured. The results showed that colchicine relieved ultrastructural injury of liver cells and reduced the number of active fibroblasts and collagen microfibrils. The area of collagen microfibrils measured in the liver of the infected rabbits and colchicine-treated rabbits accounted for 42.5% and 0.2%, respectively (P less than 0.01), suggesting that colchicine has therapeutic effect against schistosomal liver fibrosis.

Animals↗
PubMed1989

The use of nickel-titanium alloy in orthopedic surgery in China.

A new biomaterial made of nickel and titanium with its shape-memory characteristics has been manufactured, investigated, and used in Shanghai, China. Since 1981, this biomaterial has been used in 265 cases clinically, among which 71 involved orthopedic surgery. Results are satisfactory without failure in our short-term follow up. This preliminary report of the use of this new biomaterial with the unique characteristic of being able to recover to its original shape with particular transformation temperatures indicates its potential for opening a new field for investigation in surgery. Research to discover appropriate ratios of nickel and titanium for specific usage is underway. The interest and cooperation between the medical and engineering professions may eventually solve the problems through mutual efforts and result in improved shape-memory biomaterials.

Alloys↗
PubMed1989

[Studies on the fine structure of Toxoplasma gondii tachyzoite].

Toxoplasma gondii tachyzoite was crescent-shaped. The pellicle of the parasite consisted of two membranes. The anterior end contained the polar ring and conoid, the former being the thickened inner membrane and the latter a cylindrical organelle which was made up of about 10 filaments arranged in an oblique row. The subpellicular microtubules numbering 22 originated at the polar ring and extended to the posterior end. The rhoptries extended from the conoid and terminated anterior to the nucleus with a narrow dense neck and an enlarged posterior portion with a glandular structure. The rhoptries perhaps had a secretory function and the conoid might be related to the invasion of the tachyzoite into the host cell.

Animals↗
PubMed1989

[Effect of berberine on slow inward ionic current in guinea pig ventricular papillary muscle].

Using a single sucrose gap voltage clamp technique, it was found that berberine hydrochloride (Ber-HCl) had a dose-dependent biphasic effect on Isi of guinea pig papillary muscle. It was more difficult to wash out the inhibitory effect of Ber-HCl on Isi. In the initial stage of the experiment, Ber-HCl 72 mumol/L and 365 mumol/L greatly improved the influx of extracellular Ca2+ and increased the amplitude of Isi. As the drug perfusion was prolonged, however, Ber-HCl dramatically blocked Ca2+ channels and decreased the influx of extracellular Ca2+ consequently, Isi was reduced in amplitude and later disappeared. This experiment further revealed the mechanisms of action of Ber on cardiac contractility and for the treatment of arrhythmias.

Animals↗