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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 1,333 records · Page 74Linked to original sources
PubMed1997

Infectious endocarditis and sudden unexpected death: incidence and morphology of lesions in intravenous addicts and non-drug abusers.

BACKGROUND: Intravenous drug (IVD) use is a wellknown risk factor for infectious endocarditis (IE), but there are few morphologic and epidemiologic data comparing IVD-related and non-IVD-related IE in cases of sudden death. MATERIAL AND RESULTS: Between 1992 and 1994, acute IE was diagnosed in 13 IVD users at the Office of the Chief Medical Examiner in Maryland, indicating a yearly incidence of IE-related sudden unexpected deaths of 12 per 100,000. Eleven (85%) cases of acute IE occurred on apparently previously normal valves, and there was one unicuspid valve and one infected porcine prosthesis. There were three right-sided (tricuspid) lesions (23%), nine left-sided lesions (69%), and one multivalvular lesion (8%). During the same period, there were five cases of healed IE in IVD abusers, three of which involved the tricuspid valve. The prevalence of incidental healed lesions in autopsies of IVD users was 0.2%. The healed tricuspid lesions consisted of smooth-edged defects in the valve leaflet without perforations characteristic of mitral or aortic IE. The mean age of the deceased with healed lesions was 45 +/- 6 years versus 34 +/- 10 years for those with acute endocarditis (p = 0.03). During the same time period, there were six cases of acute IE among non-drug users, indicating a yearly incidence of sudden unexpected death of 0.04 per 100,000. Acute IE occurred on congenitally malformed (n = 5) or prosthetic (n = 1) valves. There were two cases of incidental healed IE (mitral and aortic valves), indicating a prevalence of 0.02%. CONCLUSION: IVD users are 300 times more likely to die suddenly with IE than non-IVD users, and healed lesions are 25 times more common. Healed IE of the tricuspid valve is associated with IVD abuse, and has a characteristic gross appearance that differs from healed left-sided IE.

Adult↗
PubMed1997

A mixture model for duration data: analysis of second births in China.

In this paper we introduce a mixture model in which we combine logistic regression and piecewise proportional hazards models for analysis of duration data. The model allows simultaneous estimation of two sets of effects of covariates: one of the probability of an event and the other of the timing of the event. We illustrate the application of the model through an analysis of the effects of women's characteristics and of the acceptance of a one-child certificate on the birth of second children in China. Both factors affect the probability of having a second child, but only the acceptance of a one-child certificate has a significant and strong effect on the second-birth interval.

Algorithms↗
PubMed1997

New computer-based tools for empiric antibiotic decision support.

Since 1995 we have been developing a decision-support model, called Q-ID, which uses a series of infectious disease knowledge bases to make recommendations for empirical treatment or to check the appropriateness of current antibiotic therapy. From disease manifestations and risk factors, a differential diagnosis for the patient is generated by a diagnostic medical expert system. The resulting probability of each: disease is multiplied by the expected benefit in improved mortality and morbidity from optimal antibiotic treatment of each disease. To generate empirical treatment recommendations, site-specific data on sensitivity to antibiotics of each organism is used as an estimate of the likelihood of achieving maximum benefit for each disease on the patient's differential. Combining this data with drug and patient specific factors, the model recommends the antibiotic(s) most likely to produce the optimal benefit in this patient with the least risk and expense. In this paper the model is described, excerpts from each of the knowledge bases are presented, and performance of the model in a real case is shown for illustration.

Aged↗
PubMed1997

A case-cohort study of an early biomarker of lung cancer in a screening cohort of Yunnan tin miners in China.

We initiated the present study to evaluate the accuracy of a new epithelial biomarker of early lung cancer. We tested the hypothesis that expression of a tumor-associated antigen by exfoliated sputum epithelial cells has greater accuracy (sensitivity and specificity) for the detection of preclinical, localized lung cancer than do routine clinical detection methods. Monoclonal antibody (MAb) 703D4 recognizes heterogeneous nuclear ribonuclear protein (hnRNP) A2/B1. We compared the accuracy of hnRNP up-regulation with cytology and radiographic screening for lung cancer detection in miners who were highly exposed to tobacco smoke, radon, and arsenic in southwestern China. The results showed that MAb 703D4 detection of hnRNP expression by sputum epithelial cells had greater accuracy for the detection of lung cancer than did routine screening methods, particularly for early (localized) disease. Among 57 cases and 76 noncases at the first screening, overall MAb detection of hnRNP was more sensitive (74 versus 21% for cytology and 42% for chest x-ray) but had lower specificity (70 versus 100% for cytology and 90% for chest x-ray) than standard methods. Recognizing hnRNP up-regulation resulted in detection of approximately one-third more early cases than did the combination of X-ray and cytology. Detection of hnRNP A2/B1 expression appears to be a good initial screening test for lung carcinogenesis, as it identified 74% of those who developed subsequent clinical lung cancer. Future studies might separate individuals with high lung cancer risk by MAb detection, confirming the positives with markers having greater specificity (e.g., clinical studies that become positive later in the morphological progression).

Adult↗
PubMed1997

The prognosis of biopsy-proven lupus nephritis in chinese patients: long term follow-up of 86 cases.

OBJECTIVE: To investigate the prognosis of lupus nephritis (LN) and its influencing factors in patients with lupus nephritis in China. METHODS: A retrospective study was carried out in 86 patients followed up for at least 5 years. Clinical features, serological and immunological tests were investigated. Renal biopsies were performed at the beginning of the study and repeated in some cases during the follow-up period. All the 86 patients had serum creatinine (Scr) level less than 132.6 mumol/L at the initial presentation and were divided into three groups according to the level of Scr at the end of the study. Group I: the patients with normal renal function (Scr < 132.6 mumol/L); Group II: the patients with mild-moderate renal insufficiency (132.6 mumol/L < or = SCR < or = 530.4 mumol/L); Group III: the patients with end stage renal failure (ESRF) (Scr > or = 530.4 mumol/L). RESULTS: Forty-seven patients reached clinical remission with normal renal function, 11 had with stabilization of renal function, although the systemic lupus erythematosis (SLE) activity relapsed repeatedly, while 28 subjects developed renal insufficiency after 60-170 (mean 88.12 +/- 28.23) months of observation. ESRF rate was 11.6% in this group of patients. Eight patients died (2 died of infections and 6 died of ESRF) during the follow-up period. At the beginning of the study the rates of hypertension, persistent anemia and hematuria in Group II were 50%, 70%, and 70% respectively, being much higher than those in Group I. The calculation of AI and CI in 60 patients revealed that there were 65% of patients with AI > or = 7 and 70% of patients with CI > or = 3 in Groups II and III, while in Group I there were only 32% of patients with AI > or = 7 and 19% of patients with CI > or = 3. Sixteen cases had pathologic class changed in 48 repeated biopsies. Seven cases changed to Class IV, 5 to Class II, 3 to Class V from other classes and one to class III from Class II. CONCLUSIONS: Factors associated with the development of renal insufficiency in these lupus patients included hypertension, anemia and hematuria. Renal biopsy evaluation offered additional prognostic information and showed that patients with severe active and chronic histologic changes were at risk for developing renal insufficiency. During the clinical course, the renal classification of LN changed in certain patients, thus the histologic classification of renal morphology at initial presentation did not fully predict the outcome. Renal involvement is very common in systemic lupus erythematosis (SLE) patients. Lupus nephritis (LN) is the most common form of secondary renal disease in China. It has various and unpredictable clinical features. The risks associated with its treatment have challenged investigators to detect the factors which may influence the survival rate of patients with LN and to develop the rational approaches to therapy. Decades of intensive investigation at many centers around the world had underscored the predictive value of demographic, clinical and laboratory data prior to treatment. Controversies still existed due to the difference in environment, race and the selection criteria of patients as well as the method used to evaluate the outcome. There are still some factors which are thought to have an impact on the prognosis of LN. Most of the articles on the prognosis of patients with LN were reported from Europe and America either about Caucasian or African-American patients. The prognosis of LN and its influence in Chinese patients need more elucidation.

Adult↗
PubMed1997

Hemofiltration or hemodiafiltration with on-line production of substitution fluid: clinical observation of safety and effectiveness.

OBJECTIVE: To observe the safety and cardiovascular stability of on-line hemofiltration (HF) or hemodiafiltration (HDF) and evaluate the clinical effectiveness of one HF or HDF session in addition to two hemodialysis (HD) sessions weekly. METHODS: Forty patients were randomly divided into four groups: group predilutional (PRD) HF (filtration rate: 259-333 ml/min) group predilutional HDF (filtration rate: 167 ml/min) group postdilutional (POD) HDF (filtration rate: 83 ml/min) and group bicarbonate HD. The reduction rate of parathyroid hormone (PTH), beta 2-microglobulin (beta 2MG), alpha 1-microglobulin (alpha 1MG) and KT/V in the initial treatment of every month was observed, and the incidence of hypotension and pyretic reaction during each treatment was evaluated. RESULTS: After 4-month observation, the KT/V for Group POD HDF is better than that for the other three groups, and for Group PRD HDF is better than that for Group HF and HD. Serum level of PTH and beta 2MG was not decreased after every treatment in Group HD, and so was serum level of alpha 1MG in all groups. Significant removal of PTH and beta 2MG was observed in Group HF, PRD HDF and POD HDF. The monthly serum level of beta 2MG and KT/V were stable in all groups, but the monthly serum level of PTH tended to be decreased in Group HF, PRD, HDF, and POD HDF. The incidence of pyretic reaction in HF or HDF was the same as in HD. Although the ultrafiltration volume was significantly higher during HF or PRD HDF than during HD, the incidence of hypotension in HF or PRD HDF was similar to that in HD. CONCLUSIONS: On-line HF or HDF proved to be a safe and reliable method. POD HDF mode seems to have the best KT/V, HF or PRD HDF offers a better choice for preventing intradialytic hypotension. One HF or HDF session in addition to two HD sessions weekly is similarly effective to decrease the serum level of PTH and the proof of the clinical effectiveness of such a therapy awaits a long-term observation.

Adult↗
PubMed1997

The tension-stress effects on growth of the external anal sphincter: animal experiment and its application on treatment of anorectal stenosis.

OBJECTIVE: To evaluate the effect of continuous balloon distension on the treatment of anorectal stenosis. METHODS: Animal experiment on 17 guinea pigs and clinical study on 13 patients with anorectal stenosis were carried out. The procedure of the continuous balloon distension was followed to stimulate the growth of the anus or stenotic segment. RESULTS: In animal experiment, the procedure induced muscle growth of the external anal sphincter at a rate of 2 mm per day. The grown muscle showed good contractile ability. By histological examination, it was found that the muscle cells were hypertrophic and Schwann's cells of the nerve fibers in the muscle became hyperplastic. Under electron-microscope, the muscle sarcomeres were found splitting both transversely and longitudinally. Twelve of the 13 patients were successfully treated by continuous balloon distension within 5 to 15 days (average: 6.7 days). During 4 to 14 months follow-up, all patients defecated without difficulty. CONCLUSIONS: Continuous balloon distension may induce growth of the external anal sphincter. This procedure is an acceptable therapy for anorectal stenosis.

Adult↗
PubMed1997

Production of rhEPO with a serum-free medium in the packed bed bioreactor.

Recombinant CHO (C2) cells producing human erythropoietin (rhEPO) were cultured with DMEM:F12 media containing 5% FBS for 8-10 days in a packed bed bioreactor, then rhEPO was produced with a serum-free medium (SFM-p) which was prepared in our laboratory. The SFM-p medium can support the growth of C2 cells and the production of rhEPO, and furthermore, it easily separates rhEPO from the culture supernatant. The cell culture in a packed bed bioreactor system using SFM-p was maintained in a stable condition for 20-25 days. The expression level of rhEPO was 12-28.4 mg/L. The bioreactor productivity was 71.0 mg/L.d and increased by 12-14 fold over that of the roller bottle. The glucose consumption rate was 21 g/L.d. At the end of 30 days of perfusion circulation, a final cell density of over 3.0 x 10(7)/ml of culture volume was achieved. Since the cells were entrapped in the polyester disk, the culture supernatant contained only a few detachment cells. Variations in lactate and ammonia production in the reactor were observed, and results showed that the productions of lactate and ammonia by the bioreactor were 3.5 g/L and 5 mmol/L, respectively, and did not affect the expression of interest protein. This experiment demonstrates that SFM-p is suitable for the growth and rhEPO production of recombinant C2 in the packed bed bioreactor.

Animals↗
PubMed1997

[Changes of concentrations of umbilical blood monoamines in low birth weight infant and their clinical significance].

OBJECTIVE: To investigate the changes of concentrations of umbilical blood monoamines in low birth weight (LBW) infants and their clinical significance. METHODS: By fluorescence spectrophotometry, the concentrations of umbilical plasma norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in 18 LBW before and after delivery were measured and compared with 20 normal birth weight (NBW) infants. RESULTS: The concentration of all monoamines, especially of the 2 catecholamines, i.e. NE and DA, were markedly lower in LBW than that in NBW (P < 0.05-0.01), regardless of prepartus or postpartus; the concentrations of all monoamines in postpartal umbilical plasma in both of LBW and NBW were higher than those in prepartal, and the increase of NE in NBW showed significant difference (P < 0.05). CONCLUSIONS: The decrease of all monoamines, especially of catecholamines in LBW could be one of the reasons causing the increase of mortality and the decrease of mental and physical development in LBW.

Dopamine↗
PubMed1997

Effects of cyclosporine A on serum and urinary soluble interleukin-2 receptor in patients with lupus nephritis.

OBJECTIVE: To evaluate the association of the level of urine and serum soluble interleukin-2 receptor (sIL-2R) with disease activity and response to cyclosporine A (CsA) therapy in patients with lupus nephritis (LN). METHODS: Sixteen hospitalized patients with LN were studied. At admission, fifteen patients had type IV-LN and one had type V-LN. All patients received CsA 6 mg/kg per day for 6-8 weeks, then tapered off gradually to 2 mg/kg per day. The levels of urinary and serum sIL-2R were determined by enzyme-linked immunosorbent assay (ELISA). Serum antinuclear antibody (ANA), anti-dsDNA antibody (A-ds-DNA), complement C3 and C4, total IgG, creatinine, urinary red blood cells and protein excretion, and lymphocyte subpopulations in the peripheral blood were also measured before and after CsA treatment. RESULTS: In LN patients, both urinary (534 +/- 101 U/ml) and serum SIL-2R levels (326 +/- 148 U/ml) were higher than those in normal controls. These findings were associated with higher levels of peripheral blood CD4 + and CD8 + lymphocytes (29.3 +/- 4.24 and 28.6 +/- 9.12%), higher titer of serum anti-ds-DNA, lower levels of serum complement C2 and C4 (0.98 +/- 0.23 and 0.24 +/- 0.12 g/L), as well as more proteinuria (Upro 2.99 +/- 0.76 g/24 hrs) and hematuria (URBC 83.9 +/- 95.2 10(4)/ml). These abnormalities were gradually ameliorated by CSA therapy. The changes in the levels of both serum (116 +/- 58.6 U/ml) and urine (136 +/- 43.2 U/ml) SIL-2R induced by CsA (at 8 weeks) were correlated with the changes in the levels of CD4 + and CD8 + cells (23.2 +/- 3.30 and 26.7 +/- 3.54%), degrees of immune abnormalities (serum C3 and C4 1.28 +/- 0.14 and 0.42 +/- 0.06 g/L), and renal injuries (Upro 1.07 +/- 0.46 g/24 hrs, URBC 5.82 +/- 3.15 10(4)/ml). CONCLUSIONS: These results suggest that serum and urinary sIL-2R are sensitive markers for the disease activity in patients with LN. CsA, a powerful immunosuppressive agent, significantly improves both immunologic disorders and renal functional impairments, the mechanism of which on patients with LN appears to inhibit the lymphocyte activation in the peripheral blood and renal tissues as indicated by the decrease in sIL-2R levels.

Adolescent↗
PubMed1997

Serological investigation on human trichinellosis spiralis in Hubei Province of PR China.

PVC-ELISA for detection of human trichinellosis and its value of field application was explored during 1988-1994. Sera of 56 cases of clinically confirmed trichinellosis were tested for serum Trichinella antibodies by way of PVC-ELISA, and the positive rate was 100%. When the sera of 80 cases of healthy persons from non-endemic areas were tested for trichinellosis, they were all negative. For the purpose of exploring the cross-reaction of PVC-ELISA used for detection of trichinellosis, sera from 144 cases of other parasitoses were tested. Among them, the sera of 80 cases of schistosomiasis japonica for trichinellosis were negative; 30 cases of paragonimiasis and 30 cases of clonorchiasis were also negative. Among sera of 4 cases of cysticercosis, there was only one positive. The results showed that PVC-ELISA for trichinellosis had a high sensitivity and specificity. For field application, a population of 800 from endemic areas were examined by PVC-ELISA, 85 (10.63%) were positive. The infected persons were mainly in Xiangfan region of Hubei Province. The percentage of the positive of trichinellosis in Xiangfan region was 64.71% (55/85). The positive rate of males and females was 13.41% (57/425) and 7.47% (28/375), respectively. There was a difference among the age groups, with the highest in those > or = 20 years. The findings of this field investigation suggested that the infection rate of trichinellosis spiralis was high in this province, especially in the Xiangfan region; and that PVC-ELISA was suitable for field application. The emphasis of trichinellosis control and research of this province should be in the Xiangfan region.

China↗
PubMed1997

[A correlation study on homocysteine metabolism in pregnant women and neural tube defects in urban and rural areas].

Serum levels of homocysteine, folic acid and vitamin B12 in pregnant women in urban and rural areas were compared to study the relationship between homocysteine metabolism and neural tube defects. Four hundred and eleven serum specimens were sampled randomly from a serum bank for women with early pregnancy in Beijing area, 195 from urban and 216 from rural. Their levels of homocysteine were determined by high performance liquid chromatography combined with electrochemical methods, and those of folic acid and vitamin B12 by radioimmunoassay. Results showed that level of homocysteine was significantly higher in rural pregnant women than that in urban, with 9.31 mumol/L and 5.73 mumol/L, respectively, level of vitamin B12 was lower in rural than that in urban women, with 210.09 pmol/L and 233.35 pmol/L, respectively, and level of folic acid was higher in rural than that in urban women, but no significant difference in deficiency of folic acid between rural and urban was found. The average ratio of folic acid to homocysteine and that of vitamin B12 to homocysteine were higher in rural than those in urban women. It suggests that abnormal metabolism of homocysteine usually correlates with high incidence of neural tube defects in rural area.

Adult↗
PubMed1997

Strong correlation between c-erbB-2 overexpression and overall survival of patients with oral squamous cell carcinoma.

Overexpression of c-erbB-2 (also known as HER-2/neu) has been found in many human cancers, including head and neck squamous cell carcinoma (SCC). We therefore examined expression of the oncoprotein in oral SCC primary tumor samples and compared its relationship with clinical stages and survival rate. Out of 80 cases of oral SCC, high expression level (++ or +++) of c-erbB-2 was found in 41 cases. Of the 80 cases with follow-up information, 39 were further investigated for the correlation of expression level of c-erbB-2 and survival rate. Overexpression of the oncoprotein was significantly correlated with shorter overall survival, and the patients with low and no expression of c-erbB-2 had much higher survival rates. Overexpression of c-erbB-2 was also significantly correlated with nodal stage and metastasis. We found that high expression level of c-erbB-2 was frequently detected in oral cancer cell lines but not in the other head and neck SCC cell lines. Thus, we conclude that overexpression of c-erbB-2 is a frequent event in oral SCC and is correlated with poor survival and may be used as a poor prognostic factor.

Adolescent↗
PubMed1997

[Wavelet transform and its application to brain evoked potentials].

Evoked potentials (EP) is an important bioelectric signal for studying the neural processes, but it is immersed in very strong background noise. Extraction of EP from a single trial has been a topic of great theoretical and clinical interest. In this paper, a new signal processing method--wavelet transform is introduced and several applications are given.

Animals↗
PubMed1997

[Effects of vasoactive intestinal peptide, alpha-chymotrypsin, pancreozymin, lipase, phospholipase A2 and collagenase on the viscoelasticity properties of red blood cell suspension].

Using Low Shear-30 Rheometer, we studied the effects of vasoactive intestinal peptide, alpha-chymotrypsin, pancreozymin, lipase, phospholipase A2 and collagenase on the viscoelasticity properties of RBC suspension. The result showed that these drugs could increase the values of eta 0.512 and A. I. It suggests that these drugs could increase the degree of RBC aggregation. Among the drugs and concentrations, there is no significant difference.

Blood Viscosity↗
PubMed1997

[A study on familial aggregation of hepatitis virus infection in Fujian province].

In nine disease surveillance points of Fujian Province, positive serum antibody against hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAg), antibody against hepatitis Cvirus (anti-HCV) and antibody against hepatitis E virus (anti-HEV) in people of 1,237 families were determined and their distribution was analyzed to study familial aggregation of hepatitis virus infection by fitting to binomial distribution. Results showed that chi 2 of goodness-of-fit to binomial distribution was 49.89, 217.91 and 27.39 for anti-HAV, HBsAg and anti-HEV respectively, all with P < 0.001, indicating very obvious familial aggregation in HAV, HBV and HEV infection, with aggregation rates of 84.13%, 34.83% and 35.23% respectively. It suggests that familial aggregation is mainly caused by mother to infant transmission and horizontal transmission in families, and HEV infection can be transmitted through sex.

Binomial Distribution↗