Biomedical subjects

Mei Wang

Publications and source records attributed to Mei Wang.

154 records · Page 9Linked to original sources

PubMed2002

Evaluation of 70/30 poly (L-lactide-co-D,L-lactide) for use as a resorbable interbody fusion cage.

OBJECT: Titanium lumbar interbody spinal fusion devices are reported to be 90% effective in cases requiring single-level lumbar interbody arthrodesis, although radiographic determination of fusion has been debated. METHODS: Using blinded radiographic, biomechanical, histological, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(L-lactide-co-D,L-lactide) interbody fusion device packed with autograft or recombinant human bone morphogenetic protein-2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologically confirmed fusion was demonstrated at 3 months to 24 months postimplantation. Device degradation was associated with a mild to moderate chronic inflammatory response at all postoperative sacrifice times. CONCLUSIONS: Use of this material in interbody fusion may be a viable alternative to metals.

Absorbable Implants↗

PubMed2002

Expression of p53 and C-myc genes and its clinical relevance in the hepatocellular carcinomatous and pericarcinomatous tissues.

AIM: To investigate the possible roles of p53 and C-myc genes in the primary hepatocellular carcinogenesis and the relationship between the liver hyperplastic nodule (LHN) and hepatocellular carcinoma(HCC). METHODS: The expression of p53 and C-myc genes was detected immunohistochemically in 73 and 60 cases of HCC and pericarcinomatous tissues, respectively. RESULTS: The positive expression of p53 in HCC was significantly higher than that in pericarcinomatous tissues (P<0.05). In pericarcinomatous tissues, the p53 expression was observed only in LHN, but not in liver cirrhosis (LC) and normal liver tissues. The positive expression rate of C-myc in HCC or LHN was significantly higher than that in LC or normal liver tissues (P<0.05 and P<0.01), however, no significant difference was found between HCC and LHN (P>0.05). The positive expression rate of p53 and C-myc in HCC was correlated with the histological differentiation, that in the poorly differentiated was significantly higher than that in well differentiated samples (P<0.05). CONCLUSION: The overexpression of p53 and C-myc genes might play a role in the carcinogenesis of HCC; And LHN seems a preneoplastic lesion related to hepatocarcinogenesis; No evidence supports that LC contribute directly to the hepatocarcinogenesis.

Carcinoma, Hepatocellular↗

PubMed2002

Evaluation of 70/30 D,L-PLa for use as a resorbable interbody fusion cage.

Titanium lumbar interbody spinal fusion devices are reported to be 90% effective for single-level lumbar interbody fusion, although radiographic determination of fusion has been debated. Using blinded radiographic, biomechanic, histologic, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(L-lactide-co-D,L-lactide) (70/30 D,L-PLa) interbody fusion device packed with autograft or rhBMP-2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologic fusion was demonstrated from 3 months to 24 months. Device degradation was associated with a mild to moderate chronic inflammatory response at all postoperative sacrifice times.

Absorbable Implants↗

PubMed2002

Left ventricular long-axis changes in early diastole and systole: impact of systolic function on diastole.

Impaired long-axis motion is a sensitive marker of systolic myocardial dysfunction, but no data are available that relate long-axis changes in systole with those in diastole, particularly in subjects with diastolic dysfunction and a 'normal' left ventricular (LV) ejection fraction. A total of 311 subjects (including 105 normal healthy volunteers) aged 20-89 years with variable degrees of systolic function (LV ejection fraction range 0.15-0.84) and diastolic function were studied using tissue Doppler echocardiography and M-mode echocardiography to determine mean mitral annular amplitude and peak velocity in systole and early and late diastole. The LV systolic mitral annular amplitude (S(LAX), where LAX is long-axis amplitude) and peak velocity (S(m)) correlated well with the respective early diastolic components (E(LAX) and E(m)) and late diastolic (atrial) components (A(LAX) and A(m)). A non-linear equation fitted better than a linear relationship (non-linear model: S(LAX) against E(LAX), r(2)=0.67; S(m) against E(m), r(2)=0.60; S(LAX) against A(LAX) and S(m) against A(m), r(2)=0.42). After adjusting for age, sex and heart rate, linear relationships of early diastolic (E(LAX), r(2)=0.70; E(m), r(2)=0.60) and late diastolic (A(LAX), r(2)=0.61; A(m), r(2)=0.64) long-axis amplitudes and velocities with the respective values for S(LAX) and S(m) were found, even in those subjects with apparently 'isolated' diastolic dysfunction. Long-axis changes in systole or diastole did not correlate with Doppler mitral velocities. We conclude that ventricular long-axis changes in early diastole are closely related to systolic function, even in subjects with diastolic dysfunction. 'Pure' or isolated diastolic dysfunction is uncommon.

Adult↗

PubMed2002

[Two types of event-related brain slow potentials in auditory location discrimination (correction of dicrimination) task].

Objective. To study the difference between two types of event-related brain potentials (ERPs) in auditory location discrimination task. Method. Event-related potentials (ERPs) in auditory location discrimination task were recorded in 14 normal subjects and were compared with head-down tilt (HDT) and head-up tilt (HUT) conditions. Result. 1) The subjects could be divided into group I (n=7) and group II (n =7) according to the feature of the target ERPs component (P3). The difference between the two groups was mainly that there was a negative slow wave after 150 ms in the ERPs of group II subjects, and that the reaction time and error rate in II group was higher than in I group. These data indicated that the psychological load on group II was larger than that on group I. 2) The reduction of mean slow potential amplitude during HDT was more significant in group II than in group I. Conclusion. The slow potential amplitude of ERPs may reflect the psychological load and the brain function state. Attention should be paid to the feature of auditory ERPs in space medical practice.

Acoustic Stimulation↗

PubMed2002

[Results of combined therapy for 1260 patients with small cell lung cancer].

OBJECTIVE: To evaluate the efficacy of combined modality treatment and determine the prognostic factors for small cell lung cancer (SCLC). METHODS: From January 1974 to December 1995, 1260 patients with SCLC treated were retrospectively evaluated, with limited lesions in 732 patients, extensive lesions in 500 and stage unrecorded in 28. 553 patients were alloted into chemotherapy + radiotherapy (C + R) group, 355 into C + R + C group, 97 into R + C group, 126 into C group, 64 into R group and 65 into surgery (S + C + R) group. Patients with limited lesions received 2 - 4 cycles of chemotherapy including COMC, COMP, COMVP and CE-CAP. Radiotherapy was given to a dose of 40 - 70 Gy/4 - 7 w. Radiation portals for patients with limited lesions encompassed the primary tumor, hilar lymphatic drainage areas, partial mediastinum and bilateral supraclavicular regions. Patients with extensive lesions mainly received chemotherapy with or without palliative irradiation. RESULTS: The overall CR and PR rates were 26.7% and 52.3%. Local recurrence and distant metastasis rates were 58.8% and 61.5%. The 1-, 3- and 5-year survival rates were 50.2%, 14.7% and 11.7%, with median survival time of 12 months. The era, sex, age, tumor stage and treatment modality were all significant prognostic factors by both uni-variate and multi-variate analyses (P < 0.05). The result of S + C + R rated the best among these modalities and the result of C + R + C was superior to C + R, though the difference of which was not significant. CONCLUSION: Surgical resection should be considered as one part of comprehensive therapy for small cell lung cancer patients with limited lesions whenever possible. On top of routine chemotherapy early administration of radiotherapy is advisable.

Adult↗

PubMed2002

[Clinical value of prophylactic radiotherapy after curative resection of esophageal carcinoma].

OBJECTIVE: To evaluate the clinical value of prophylactic radiotherapy for esophageal carcinoma after curative operation. METHODS: 495 esophageal squamous cell cancer patients who had undergone radical resection were randomized by the envelope method into a surgery alone group (S, 275) and a surgery plus radiotherapy group (S + R, 220). Radiation treatment was started 3 - 4 weeks after operation. The portals encompassed the whole mediastinum and bilateral supraclavicular areas. A mid-plane dose of 50 approximately 60 Gy in 20 approximately 30 fractions over 5 approximately 6 weeks was delivered. RESULTS: 1. Survival rate: the overall 5-year survival rate was 39.4%. Those of S alone and S + R groups were 37.1% and 41.3% (P = 0.447 4). The 5-year survival rate for Stage III patients were 13.1% in S alone group and 35.1% in R + S group (P = 0.002 7), 2. Pattern of failure: The incidence of local recurrence intra-thoracic lymph node metastasis, anastomotic recurrence and extra-thoracic lymph node metastasis in S + R group (16.2%, 0.5% and 3.1%) were lower than those (25.9%, 5.8% and 13.2%) (P < 0.05) in S alone group and 3. COMPLICATIONS: the anastomotic stricture frequencies were similar in the two groups (S 1.8%; S + R 4.1%). CONCLUSION: 1. Prophylactic radiotherapy is able to improve the survival rate of stage III patients treated by radical resection, 2. Postoperative radiotherapy is able to reduce the incidence of failure by recurrence in the intra-thoracic lymph nodes and anastomotic recurrence to where radiation therapy had been given, 3. Postoperative radiotherapy does not increase the incidence of anastomotic stricture.

Adult↗

PubMed2001

Association of inflammation and malnutrition with cardiac valve calcification in continuous ambulatory peritoneal dialysis patients.

Cardiac valve calcification (VC) has long been regarded as a consequence of aging and abnormal calcium-phosphate metabolism in uremic patients. In view of the recent recognition of association among inflammation, malnutrition, and atherosclerosis, the possible role of inflammation and malnutrition in VC was investigated. Inflammatory markers (including C-reactive protein [CRP], fibrinogen, and basal metabolic rate) and nutritional status (assessed using serum albumin, subjective global nutrition assessment, and handgrip strength) were examined, in addition to calcium phosphate parameters and other traditional cardiovascular risk factors, including gender, smoking habits, BP, and lipid profile, in relation to VC in 137 patients who were on continuous ambulatory peritoneal dialysis. Compared with patients with no VC, patients with VC not only were older (60 [10] versus 54 [12] yr; P = 0.005), had higher plasma phosphate (1.89 [0.52] versus 1.64 [0.41] mmol/L; P = 0.003), and had higher parathyroid hormone (83 [40, 145] versus 38 [16, 71] pmol/L; P = 0.001) but also had higher CRP (4.5 [0.1, 13.4] versus 0.2 [0.1, 4.4] mg/L; P = 0.004), had higher fibrinogen (6.6 [1.9] versus 5.7 [1.3] g/L; P = 0.002), and had lower serum albumin (26 [4] versus 29 [3] g/L; P = 0004). Twenty-three percent of patients with VC versus 17% of patients with no VC were moderately to severely malnourished according to subjective global nutrition assessment (P = 0.05). Even after adjustment for patients' age, duration of continuous ambulatory peritoneal dialysis, diabetes, and calcium x phosphate product, cardiac VC remained strongly associated with CRP (odds ratio, 1.05; P = 0.026) and albumin (odds ratio, 0.85; P = 0.01). The data suggest that VC not only is a passive degenerative process but also involves active inflammation, similar to that seen in atherosclerosis. The presence of uncontrolled hyperphosphatemia and hyperparathyroidism further accelerates the progression of calcification. The data also indicate that VC and atherosclerosis should be considered as associated syndromes, sharing similar pathogenic mechanisms, namely active inflammation.

Adult↗

PubMedDate not supplied

Intradiscal pressure and kinematic behavior of lumbar spine after bilateral laminotomy and laminectomy.

BACKGROUND CONTEXT: Bilateral laminotomy has been proposed as an alternative to laminectomy for decompression of lumbar spinal stenosis. Preservation of the posterior midline ligaments with laminotomy is presumed to maintain spinal segment stability. There have been no previous studies that directly compare the amount of destabilization and increase in disc pressures between the two procedures. PURPOSE: To quantify spinal segmental instability caused by bilateral laminotomy and laminectomy, and to compare the central and peripheral intradiscal pressures after the two procedures. STUDY DESIGN/SETTING: Mechanical testing of the lumbar motion segments of calf spines. METHODS: Nine fresh calf spines were tested under flexion, extension, lateral bending and axial rotation, intact first, then after laminotomy and laminectomy at the level of L4-L5. Four miniature pressure transducers were implanted in the central and peripheral disc at L4-L5 to measure intradiscal pressures. Three-dimensional motion was measured with motion analysis system. RESULTS: Comparing with bilateral laminotomy, laminectomy showed significant increase in segmental motion at the surgical level in flexion (16%, p<.05), extension (14%, p<.04) and right axial rotation (23%, p<.03). In flexion, the stress at the anterior annulus increased a nonsignificant 20% after laminotomy, but significant 130% after laminectomy (p<.02). In the intact spine, the posterolateral annulus experienced the highest stress with lateral bending to the same side when compared with other loading directions. This stress remained unchanged after laminotomy but increased 9% after laminectomy (p<.06). In rotation, axial intradiscal stresses were evenly distributed and unchanged after each procedure. CONCLUSIONS: Laminectomy causes more destabilization of a spinal motion segment than laminotomy and significantly increases disc stress in the anterior annulus.

Animals↗

PubMedDate not supplied

New contributions to two heterotrichous ciliates, Folliculina simplex (Dons, 1917), Condylostoma curva Burkovsky, 1970 and one licnophorid, Licnophora lyngbycola Fauré-Fremiet, 1937 (Protozoa, Ciliophora): descriptions of morphology and infraciliature.

The living morphology and infraciliature of two heterotrichous and one licnophorid ciliates from the north China seas, i.e. Folliculina simplex (Dons 1917), Condylostoma curva Burkovsky, 1970, and Licnophora lyngbycola Fauré-Fremiet, 1937, were investigated using protargol impregnation and in vivo observations. Updated diagnoses and redescriptions of each species are provided. The improved diagnosis of Folliculina simplex is as follows: blue-greyish to blue-greenish Folliculina with broad and unequal-sized peristomial lobes; adoral zone of membranelles comprises about 400 membranelles and forms two-and-half turns within buccal cavity; paroral membrane extends entire length of adoral zone of membranelles; about 50 somatic kineties in mid-body; single ovoid to ellipsoid macronucleus and several micronuclei; lorica vase-shaped, about 150-250 microm long, often with jelly-like covering and inconspicuous neck; marine habitat. Improved diagnosis for Licnophora lyngbycola: marine Licnophora with cup-shaped body and glabrous adhesive disc with which the organism attaches to the filaments of the colourless cyanobacterium Lyngbya; in vivo 80-130 microm long; about 140 adoral membranelles, one micronucleus and a single C-shaped, moniliform macronucleus consisting of about 14 nodules; two specialized dorsal kineties; five peripheral rings on adhesive disc, the 2nd, 3rd, and 5th (outermost) which are incomplete. Based on the Qingdao population, an improved diagnosis for Condylostoma curva is supplied: yellow-brownish Condylostoma with oval to elongated body shape; about 150-350 microm long in vivo; about 68-108 membranelles in adoral zone of membranelles, 4-8 frontal cirri, 22-32 somatic kineties; macronucleus moniliform with 5-13 nodules; with cortical granules; marine habitat.

Animals↗