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Biomedical subjects

K Wang

Publications and source records attributed to K Wang.

At least 289 records · Page 16Linked to original sources
PubMed1998

Childhood diabetes in China. Enormous variation by place and ethnic group.

OBJECTIVE: To investigate the incidence rate of IDDM in China. RESEARCH DESIGN AND METHODS: The Chinese IDDM registry was established in 1991 as part of the World Health Organization's Multinational Project for Childhood Diabetes (DiaMond) project. Twenty-two centers were developed to monitor the incidence of IDDM in children < 15 years of age. The population under investigation includes > 20 million individuals, representing approximately 7% of the children in China. Capture-recapture methods were used to estimate the ascertainment. RESULTS: The overall ascertainment-corrected IDDM incidence rate in China was 0.51 per 100,000, the lowest rate ever reported. There was a 12-fold geographic variation (0.13-1.61 per 100,000). In general, the incidence rate was higher in the north and the east. There was a sixfold difference among ethnic groups (highest: Mongol group, 1.82 per 100,000; lowest: Zhuang group, 0.32 per 100,000). CONCLUSIONS: China has an extremely low overall IDDM incidence rate. China also has the greatest geographic and ethnic variation seen for any country.

Adolescent↗
PubMed1998

The comparative biology of latent herpes simplex virus type 1 and type 2 infections: latency-associated transcript promoter activity and expression in vitro and in infected mice.

HSV-1 and HSV-2 express abundant latency-associated transcripts (LATs) without which these viruses reactivate in animals inefficiently. To further characterize the importance of LATs to the comparative biology of latent HSV-1 and -2 infections, we assessed the relative activities of the viral LAT promoters in vitro using transient transfection assays, and the accumulation of LATs in vivo using a mouse ocular infection model. In vitro, the HSV-2 LAT promoter proved to be six to tenfold more potent than the HSV-1 promoter in driving reporter gene expression. In mice HSV-1 and -2 achieved comparable levels of virus replication in the eye, but HSV-2 grew to higher titers than HSV-1 in trigeminal ganglia and brain. Quantitative-competitive DNA and RNA (RT) PCR and in situ hybridization showed that ganglia latently infected with HSV-2 contained sixfold more copies of DNA (P=0.003), eightfold more LATS (P=0.01), and ninefold more LAT in situ-positive neurons. However, the numbers of LATs per latent genome were equivalent for both viruses. Although the HSV-2 LAT promoter is more potent than the HSV-1 promoter in transient expression assays, the accumulation of HSV-1 and 2 LATs in mouse trigeminal ganglia is comparable.

Animals↗
PubMed1998

[Study on the epidemiological characteristics of diabetes mellitus and IGT in China].

A community-based survey on diabetes mellitus (DM) and impaired glucose tolerance (IGT) was carried out in 11 provinces/autonomous regions/municipalities of China from July 1995 to June 1997, using stratified cluster sampling method and diagnostic criteria recommended by WHO. A total number of 42,751 persons aged 20-74 years having lived in the communities longer than 5 years, were selected as research subjects. Results showed that the prevalence rates of DM and IGT standardized by age were 3.21% (95% CI: 3.05%-3.37%) and 4.76% (95% CI: 4.56%-4.96%) respectively; with a ratio of DM to IGT 1:1.5. The prevalence rates of DM and IGT increased parallelly with the increase of age. Among the 20-39 years old, the prevalence rates of DM and IGT were 1.01% and 2.70% respectively, while both of them exceeded 7% and 11% among people aged 50-59 years and above 60 years.

Adult↗
PubMed1998

Changes of skin perfusion after photodynamic therapy for port wine stain.

OBJECTIVE: To obtain an objective assessment of the curative effectiveness of photodynamic therapy (PDT) for port wine stain (PWS), we investigate the relationship between the microvascular perfusion changes of PWS and the blanching of the lesions before and after PDT. METHODS: Twenty-four patients (18 females and 6 males with a total of 28 lesions) suffering from PWS were treated with PDT. The lesions of various extents were located on the face and neck. After intravenous injection of photosensitizer hepatoporphyrin derivative (HpD), the copper vapor laser was adopted as light source and the lesions of PWS were irradiated. The laser Doppler perfusion imager (LDI) was used to measure the microcirculatory perfusion of PWS before and after PDT and comparison with the normal skin was done. RESULTS: All the lesions showed remarkable decrease of tissue perfusion after PDT. It was shown that the mean, maximal and minimal values of tissue perfusion in the pre-treatment group were significantly higher than those in control group (P < 0.01). Six months after PDT, the mean, maximal and minimal values of perfusion with the lesions were reduced, with significant difference from pre-treatment group (P < 0.01), but no significant difference from control's. The colors of lesions were correlated with decrease of microcirculatory perfusion, which became lightened close to normal skin color without causing any scarring. CONCLUSIONS: PDT is one of the most effective modalities for PWS. The microcirculation perfusion can reflect the degrees of PWS objectively. The curative effectiveness of PDT for PWS is due to tissue microcirculation response.

Adolescent↗
PubMed1998

Experimental Evaluation of a New Single Wire Tantalum Coil Coronary Stent (Wiktor-iª).

To improve scaffolding properties, a new more densely woven Wiktor stent, the Wiktor-iª stent, was developed. Although the metal coverage remains still low compared to other stents, increased metal/vessel area raises the concern of increased thrombogenicity and neointimal hyperplasia. In this study we evaluated the Wiktor-i stent in a porcine peripheral and coronary model and compared the thrombogenicity and neointimal hyperplasia with the Wiktor-GX coronary stent. In a first study, a Wiktor-i and a Wiktor-GX coronary stent were implanted symmetrically in a preselected side branch of the right and left iliac artery of 10 healthy pigs. Quantitative vessel analysis showed comparable data before, immediately after and at follow-up. Hyperplasia measured by morphometry was also comparable in both groups (Wiktor-GX: 1.43 mm2 vs. Wiktor-i: 1.17 mm2, NS). Also, area stenosis was very similar (Wiktor-GX: 32% vs. Wiktor-i: 29%, NS). In a second study, 20 Wiktor (Wiktor-i: n=10, Wiktor-GX: n=10) coronary stents were implanted in the right coronary artery of 20 healthy pigs. Quantitative coronary analysis before, immediately after and at follow-up was comparable in both stents. The hyperplasia measured morphometrically was also comparable in both stents. (Wiktor-GX: 1.51 +/- 0.47 mm2 vs. Wiktor-i: 1.46 +/- 0.66 mm2, NS). Also the area stenosis was not significantly different (Wiktor-GX: 31% vs. Wiktor-i: 35%). In conclusion, this study shows that the increased metal/vessel area of the Wiktor-i stent does not result in an increased neointimal hyperplasia. Both stents show to be very biocompatible when implanted in porcine coronary and peripheral vessels.

Journal Article↗
PubMed1998

Stent Deployment Pressure Defines the Stent/Vessel Wall Relationship and has Important Implications for Early and Late Outcome.

OBJECTIVE: This study evaluates the effect of stent deployment pressure on stent deployment, coronary vessel injury, subacute reclosure and foreign body reaction in a porcine coronary model. METHODS: Stainless steel coil stents were deployed in the right coronary artery of 30 pigs either using a deployment pressure of 4 atm (group I), 8 atm (group II), or 14 atm (group III). Serial quantitative angiographic studies together with morphometric analysis of the stented vessels were performed. RESULTS: Three pigs died within 48 hours due to subacute thrombosis (group I: n = 1, group II: n = 0, group III: n = 2). Another 4 stents were found occluded at day 7 (group I: n = 3, group II: n = 0, group III: n = 1). Imperfect stent alignment was found in 8 coronary arteries (group I: n = 7, group II: n = 1, group III: n = 0). Deep protrusion of stent filaments was found in 7 coronary arteries (group I: n = 0, group II: n = 1, group III: n = 6). Area stenosis at 6 weeks of the patent vessels was as follows: 75.7 +/- 15.2% in group I, 31.8 +/- 12.3% in group II, and 66.9 +/- 21.4% in group III, p < 0.001). CONCLUSION: In a porcine coronary model, stent deployment pressure resulting in an optimal alignment and a minimal coronary vessel injury leads to minimal neointimal hyperplasia.

Journal Article↗
PubMed1998

Intravascular Low Power Red Laser Light as an Adjunct to Coronary Stent Implantation Evaluated in a Porcine Coronary Model.

BACKGROUND: It is believed that restenosis following coronary interventions is the result of endothelial denudation that leads to thrombus formation, vascular remodeling, and smooth muscle cell proliferation. We previously demonstrated that low power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo and reduces restenosis in a small animal model. The present study investigated the effectiveness of intravascular LPRLL therapy in the reduction of restenosis following stenting in a porcine model. METHODS AND RESULTS: Stents were placed in the right coronary artery of domestic cross-bred pigs. After stent deployment, an additional inflation was performed with the laser-balloon. In group I (n = 18) no LPRLL was used; group II (n = 10) received LPRLL dosage of 10 mW for 1 minute; group III (n = 10) received LPRLL dosage of 34 mW for 1 minute. Quantitative coronary analysis of the stented vessel was performed before, immediately after stenting, and at 6 weeks. The pigs were sacrificed and histologic and planimetric analysis conducted. At 6 weeks, minimal luminal stent diameter was significantly narrower in the control group compared to the higher dose group (p < 0.05), late loss correlated inversely proportional to the dose used (r = 0.9; p < 0.03), these results were confirmed by morphometric analysis. Neointimal area was also significantly decreased in the higher dose group. CONCLUSIONS: Intravascular LPRLL contributes to reduction of angiographic restenosis and hyperplastic reaction in this animal model and seems to be dose dependent.

Journal Article↗
PubMed1998

Experimental Evaluation of a New Tubular Coronary Stent (V-Flexª).

The safety, efficacy, angiographic and histological effects of a new 316 L, SS seamless stainless steel tubular stent (V-Flexª, Global Therapeutics, Broomfield, Colorado) was evaluated in a porcine coronary and peripheral artery model. Implantation in the right coronary artery was successful in all 16 pigs. Eight pigs were angiographically controlled after 6 weeks and then sacrificed for morphometric analysis. All stented coronary vessels were widely patent at this moment and morphometric analysis showed only a mild fibromuscular neointimal hyperplasia resulting in a neointimal hyperplasia of 1.15 +/- 0.38 mm2. The remaining 8 pigs were controlled and sacrificed at 12 weeks. At that time, all stented vessels were patent and neointimal hyperplasia was 1.22 +/- 0.34 mm2. Comparison with the Palmaz-Schatzª coronary stent (Cordis, Miami, Florida) in a porcine peripheral artery model demonstrated significantly less neointimal hyperplasia at 6 weeks (1.11 +/- 0.73 vs. 2.40 +/- 0.36, p = 0.001) and at 12 weeks (1.53 +/- 0.42 vs. 2.47 +/- 0.63, p = 0.003) for the V-Flex stent. In conclusion, V-Flex coronary stent implantation in a porcine coronary and peripheral arteries results in a high procedural success rate without subacute thrombotic occlusions, despite no further anticoagulation nor antiplatelet therapy. Six and 12 week histopathological and morphometric evaluation demonstrated only a mild fibromuscular neointimal hyperplasia. Comparison with the Palmaz-Schatz coronary stent in a peripheral artery model showed significantly less neointimal hyperplasia in the V-Flex stent.

Journal Article↗
PubMed1998

[Distribution and drug-resistance of 345 strains gram-negative bacilli from hospitalized patients with lower respiratory tract infections diseases].

OBJECTIVE: To investigate the distribution and drug-resistance of gram-negative bacilli in respiratory ward. METHOD: (1) Drug-resistance was tested by Kirby-Bauer disk sensitivity method and MIC by agar doubling dilution. (2) beta-lactanase was tested by nitrocephin. (3) ESBLs was tested by E test. RESULT: (1) Among 345 strains gram-negative bacillus, klebsiella pneumoniae and pseudomonas aeruginoea was about 39.7%, 17.4%, respectively. (2) Drug-resistance rate of cefotaxime dropped from 42.9% (6 years ago) to 8.2%. (3) beta-lactamase positive rate of 345 strains bacilli was 54.5%. (4) ESBLs was negative. CONCLUSION: (1) Klebsiella pneumoniae and pseudomonas aerugries were the main pathogens in lower respiratory tract infection in hospital. (2) Although we didn't find the evidence of ESBLs, we should pay more attention to it in the future.

Bronchiectasis↗
PubMed1998

[Low vacuum as a ground simulation method for studies of gas convection heat transfer inside manned spacecraft].

Owing to reduced gravity on the orbit, the convection model of the environment inside the manned spacecraft becomes complicated, and it is difficult to simulate under 1G condition for related studies on the ground. The author described a method using low vacuum to simulate the effect of reduced gravity on gas convection heat transfer for ground studies of environmental control and lifesupport system of manned spacecraft. It is demonstrated that when suitable experimental vessel and appropriate method are used, it is possible that convection heat transfer of the environment inside the manned spacecraft flying on the orbit may be simulated successfully on the ground.

Air Conditioning↗
PubMed1998

[Production of allochtonic formations in callus cells of Salvia miltiorrhiza Bge].

OBJECTIVE: To study the effect of hormones content in the medium on of allochtonic formations in the callus from Salvia miltiorrhiza. METHOD: Study the development of allochtonic formations in the callus from explants of Salvia miltiorrhiza cultured on hormones of different content ratios in the medium. RESULT AND CONCLUSION: 2,4-D inhibits the production of water-soluble active principles and KT promotes the production of total tanshinone.

Abietanes↗
PubMed1998

[Cleft palate with problems of middle ears].

OBJECTIVE: To gain a clear idea of the function of middle ears and hearing loss in cleft palate. METHODS: 59 cleft palate cases, including 117 ears are investigated by tympanogram and hearing threshold. RESULTS: In 80.4% of patients the function of middle ears are abnormal. 59.4% ears are conductive hearing loss in various degrees. CONCLUSION: Function of middle ears in cleft palate should be regularly examined as early as possible. If it is secretory otitis media, the tympanostomy pressure equalization tubes should be inserted to compensate inadequate function of the eustachian tube so as to avoid adhesive otitis media. The methods for the prevention and reduction of the middle ear problems with cleft palate are also suggested.

Adolescent↗
PubMed1998

[Evaluation of the treatment effect for bruxism by using myomonitor and occlusal splint].

OBJECTIVE: To evaluate the treatment effect of bruxism by using myomonitor and occlusal splint therapy. METHODS: By using EMG, audiocontrolled recorder and myollectronic recording device to record and analyse the muscles functional state before and after treatment. RESULTS: Splint therapy was more effective than the myomonitor did, such as teeth grinding stopped in 12 cases to 1 case, grinding time decreased in 13 cases to 10 cases and no significant effect in 2 cases to 17 cases. SPD and V/T curve slope of muscles decreased. CONCLUSION: This indicates that the functional state of masticatory muscles got improved. Splint therapy is one of the effective treatment method for bruxism.

Adult↗
PubMed1998

[Treatment of old femoral neck fracture with implantation of a vascularized fibular graft].

OBJECTIVE: To investigate the healing of old femoral neck fracture treated with transplantation of vascularized fibula graft accompanied with lag screw, and rehabilitation of and precaution against ischemic necrosis of femoral head. METHOD: Vascularized fibula autograft was transplanted to the anterolateral side of the femoral neck with an internal fixator of lag screw. Fibular artery and vein were anastomosed with lateral circumflex artery and vein. RESULT: 186 of 229 cases subjected to systemic X-ray films and function follow-up (3 to 15 years). The percentage of fracture healing was 93.0% the sulass rate 86.5%. CONCLUSION: Fibula with blood supply and compressed screw have a combined fixation effect of the old femoral neck fracture. Fibula is solid enough for supporting the femoral head and preventing it from collapse. Vascularized fibular grafting provides blood supply to the affected femoral head and neck, promoting femoral head restoration and reconstruction.

Adolescent↗
PubMed1998

[Corneal topography analysis after excimer laser photorefractive keratectomy].

OBJECTIVE: To study the pattern of ablation, evaluate centration and stability following excimer laser photorefractive keratectomy (PRK) for myopia. METHOD: Corneal topography of 312 patients (366 eyes) with a month, 3 months and 6 months of follow-up after PRK was examined. RESULTS: The mean decentration from the pupillary center to ablating center was 0.266 mm. In both eyes, the mean decentration was located supernasally. At one month postoperative examination, uniform ablation was 49.5%, semicircular, keyhole, kidney and dumbbell shaped ablations were 42.9% and central island one was 6.0%. Central island pattern affected the best corrected visual acuity greatly. High myopia began regression at 1-3 months after PRK. CONCLUSION: Corneal topography is essential for evaluating surface changes after PRK. Long-time stability issues are answered with continued topographic follow-up.

Corneal Topography↗
PubMed1998

[Excimer laser in situ keratomileusis for treatment of myopia].

OBJECTIVE: To evaluate the effectiveness of excimer laser in situ keratomileusis (LASIK) for treatment of myopia. METHODS: 928 eyes of 678 myopic patients who received LASIK were studied. The patients were divided into 3 groups according to preoperative diopters (-2.00 - -6.00D, -6.10 - -10.00D & -10.10 - -20.00D). The mean follow-up was 12 months (6 - 18 months) and the results were statistically analyzed. RESULTS: 12 months after surgery, in the first group the mean residual refraction was -0.24 +/- 0.50D in 86% and 92% of eyes were in the ranges of refraction +/- 0.50D and +/- 1.00D, the uncorrected visual acuities of 0.5 and 1.0 were in 99% and 86% of the eyes respectively. In the second group, the mean residual refraction was -0.47 +/- 0.64D, the refraction of 83% and 90% of eyes was in the ranges of +/- 0.50D and +/- 1.00D, and the uncorrected visual acuities in 95% and 79% of eyes were 0.5 and 1.0 respectively. In the third group, the mean residual refraction was -0.89 +/- 1.02D, the refraction of 36% and 62% of the eyes were in the ranges of +/- 0.50D and +/- 1.00D, and the uncorrected visual acuities in 68% and 45% of the eyes were 0.5 and 1.0 respectively. 47 eyes had been retreated with LASIK. 5 eyes lost two or more lines of the best corrected visual acuity due to irregular astigmatism, decentration and progressive myopic maculopathy. CONCLUSION: The results indicate that LASIK can treat myopia in the range of -2.00 - -20.00 D effectively without vision threatening complications. Some modification of the surgical techniques and laser nomogram will help to improve predictability and stability of outcome.

Adolescent↗