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Biomedical subjects

L Li

Publications and source records attributed to L Li.

At least 1,747 records · Page 97Linked to original sources
PubMed1993

[Establishment of two cell lines secreting monoclonal antibodies against pathogenic free-living amoeba in Shanghai].

Taking Naegleria australiensis, a species of pathogenic free-living amoeba (isolated in Shanghai in 1986), as antigen, two cell lines which provided potentially permanent source of monoclonal antibodies were established by lymphocytic hybridoma technique. The results of identification showed that: (1) the two cell lines could secret two different kinds of McAbs; (2) both of the McAbs were IgG (by gel diffusion); (3) McAbs produced in BALB/c mice were at high concentrations. One of them had a titer of > or = 1:8,192 and the other > or = 1:1,024 (by enzyme linked immunosorbent assay). A decline of the titers after purification by salting-out method was shown. One of the purified McAbs had a titer of > or = 1:2,024 and the other > or = 1:128. We have adopted two ways of recovering cryopreserved cells: ordinary recovering and "direct" recovering. The latter way was more practical because it could reduce the cycle of antibody production, and avoid contamination and chromosome variation. Experiments with different doses of cells revealed that, if the latter way was used, the optimal dose was 3 to 5 x 10(6) cells per mouse.

Animals↗
PubMed1993

[Synthesis and bio-activity of coumarin derivatives and studies on its relationships between activity and lipophilicity].

4-Methyl-7-hydroxy-6 or 8-allylcoumarin, a new type of radioprotectors, has poor solubility in water and in oil, which influences markedly its absorption in body and effectiveness of peroral administration. For improving its solubility, 14 coumarin derivatives were synthesized on the basis of increasing its hydro- or lipophilicity, and studied preliminarily on their toxicities, radioprotective activities, and relations between their hydro- or lipophilicity and activities. It is found that both compounds (5a, 6a), can be dissolved in ethyl oleate and the latter in water partially as well, retain the radioprotective activities basically, and improve the survival of 65% (P < 0.01) of mice exposed to 9.0 Gy 60Co gamma-ray when administered before irradiation. In synthesis, von Pechmann reaction was improved; 6-allyl intermediate was synthesized by the method of blocking the 8-position by iodine, and the process was studied. Mannich base was synthesized under high pressure by using CH2Cl2 as C1 synthon.

Animals↗
PubMed1993

Effect of esophageal intraluminal mechanical and chemical stressors on salivary epidermal growth factor in humans.

Although various animal and clinical studies have demonstrated the significant effect of salivary epidermal growth factor (sEGF) on esophageal morphology and function, its secretory patterns still remain inadequately explored. Therefore, we have studied the impact of esophageal mechanical and chemical stimuli on sEGF in humans. sEGF was measured in saliva collected during basal conditions, chewing of parafilm, placement of esophageal tubing, inflation of intraesophageal balloons, and perfusion with NaCl, HCl, and HCl/pepsin solutions. The concentration of sEGF was measured with a radioimmunoassay kit from Amersham (Arlington Heights, IL). The concentration of sEGF in basal saliva was (mean +/- SEM) 2.08 +/- 0.22 ng/ml. Chewing the parafilm resulted in a significant decline of sEGF concentration to the value of 1.39 +/- 0.16 ng/ml (p < 0.0005). Similar decline in sEGF concentration also prevailed after placement of intraesophageal tubing (p < 0.03), and inflation of intraesophageal balloons (p < 0.01). This decline intensified significantly when prolonged esophageal perfusion with saline was implemented (p < 0.03 vs. tubing). Substitution of NaCl with HCl in the second and third perfusion periods prevented the decline in sEGF concentration, whereas HCl accompanied by pepsin enhanced sEGF concentration. The rate of sEGF output was 0.90 +/- 0.13 ng/min during basal conditions and increased significantly during parafilm chewing (1.53 +/- 0.25 ng/min; p < 0.05). However, sEGF secretion during both placement of esophageal tubing and inflation of balloons increased 4.1- and 4.9-fold, respectively (p < 0.002 and < 0.00005), over the basal value, and 2.4- and 2.9-fold, respectively, over the parafilm stimulated secretion. Subsequently, we observed a further significant decline of sEGF output (p < 0.05) which was sustained during perfusion of the esophagus with saline. Interestingly, esophageal perfusion with HCl prevented the decline of sEGF secretion observed during perfusion with saline. sEGF output during esophageal perfusion with HCl/pepsin exhibited a strong increase, reaching the value of 5.86 +/- 0.70 ng/ml. This value corresponds to a 58% increase over the secretory rate observed during mechanical stimulation by placement of esophageal tubing (3.71 +/- 0.47; p < 0.05). HCl/pepsin-induced potentiation of sEGF secretion was also highly significantly increased over both the value recorded during basal (p < 0.0005) and parafilm-stimulated (p < 0.002) conditions. Subsequent substitution of HCl/pepsin solution with a final saline perfusate still maintained enhanced sEGF output, compared with both basal (p < 0.02) and parafilm-stimulated conditions (p < 0.02).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

Exercise therapy of non-insulin dependent diabetes mellitus. Effects of acute exercise loading.

The dynamic changes of 15 parameters (divided into 6 sections in this study) relating to metabolism, platelet function, blood coagulation and hemorrheologic situation under acute exercise loading with the intensity of VO2 max 60% were observed in noninsulin dependent diabetes mellitus (NIDDM) patients. The advantage, safety and feasibility of exercise therapy were discussed.

Adult↗
PubMed1993

Organ-association phenomena during sepsis. TNF and IL-6 in different macrophages.

Sepsis was induced in rats by cecal ligation and perforation (CLP). Five and 15 hours post CLP, alveolar macrophage (AM), Kupffer cell (KC), and peritoneal macrophage (PM) were isolated and cultured for 18 hours. Culture supernatant was examined for bioactivity of tumor necrosis factor (TNF) and interleukin 6 (IL-6) and response to lipoplysaccharide (LPS) stimulation in vitro. Results showed that AM produced more TNF during sepsis as compared with KC and PM. Stimulation with LPS in vitro was responded only by AM at 15 hr after CLP. Pattern of IL-6 production was different from TNF while KC produced the highest level of IL-6 after induction of sepsis.

Animals↗
PubMed1993

Seroprevalence of parenterally transmitted viruses (HIV-1, HBV, HCV, and HTLV-I/II) in forensic autopsy cases.

HIV, HBV, HCV, and HTLV show similar modes of transmission and infection is frequently identified in certain population groups. The seroprevalence of these infectious agents and interrelation in forensic autopsy populations are described here. A total of 414 serum samples were collected sequentially from autopsy cases at the Office of the Chief Medical Examiner for the State of Maryland. All samples were tested for the presence of antibodies to HIV-1, HCV, HTLV-I/II, and hepatitis B core antigen, using Enzyme-linked Immunosorbent Assays (ELISA). Samples yielding repeatedly reactive results were confirmed by Western Blots (WB) for HIV-1 and HTLV-I/II, while for HCV confirmation, the second generation recombinant immunoblot (RIBA-2) was used. Of the 414 cases, 32.6% (135/414) were infected with at least one of the four viruses. 5.6% were seropositive for HIV-1, 23.2% for HBV, 19.1% for HCV, and 1.0% for HTLV-I/II. Intravenous drug users (IVDU) showed significant increased prevalences of HIV-1, HBV, and HCV. 83.6% of the IVDU were infected with at least one of the three viruses, 25.5% with HIV-1, and 47.3% with both HBV and HCV. The data indicate that the overall prevalence of HIV, HBV, and HCV seropositivity in the autopsy population of an inner city medical examiner office is much higher than that of the general population. Routine testing only for HIV-1 would have missed 86% of the infections with HCV or HBV. Universal precautions should be strictly employed by all personnel working in this environment.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Increased type I collagen gene expression in L-tryptophan associated eosinophilia-myalgia syndrome skin fibroblasts.

OBJECTIVE: To investigate the pathogenetic mechanisms responsible for the cutaneous fibrosis in eosinophilia-myalgia syndrome (EMS) associated with L-tryptophan ingestion. METHODS: Compare in vitro type I collagen production and steady state procollagen mRNA levels in cultured skin fibroblasts derived from healthy individuals and from 5 patients with EMS and diffuse cutaneous induration. RESULTS: Cell lines derived from the affected skin from patients with EMS exhibited greater collagen production and higher steady state levels of alpha 1(I) procollagen mRNA compared with fibroblasts from age and sex matched healthy individuals. Exposure to interferon gamma reduced collagen synthesis in the EMS fibroblast lines. The rate of in vitro transcription of the COL1A1 gene was 30% higher in nuclei isolated from collagen overproducer EMS fibroblasts than in nuclei from normal fibroblasts. CONCLUSION: Fibroblasts derived from the involved skin of patients with EMS show increased expression of the alpha 1(I) procollagen gene in vitro compared to normal skin fibroblasts. The biosynthetically activated phenotype exhibited by EMS fibroblasts appears to be due, at least in part, to transcriptional activation of type I collagen gene expression. These biochemical and molecular alterations may result in accumulation of collagen and lead to the cutaneous fibrosis in EMS.

Adult↗
PubMed1993

[Study on sodium norcantharidate albumin microspheres].

In this paper sodium norcantharidate (Na2NC) was chosen as model drug and sodium norcantharidate albumin microspheres (Na2NC AM) was prepared by an optimal procedure. The embedding nature, appearance, morphology, size and size distribution, release characteristics in vitro, freeze-drying, 60Co radiosterilization and stability of Na2NC AM were tested. The results showed that the mean size was 0.43 +/- 0.12 micron, embedding concentration was 20.34-26.75 micrograms/mg, embedding ratio was 21.9-26.4%, release characteristics in vitro was in accord with Higuchi equation. Freeze-drying and 60Co radiosterilization showed no influence on Na2NC AM. The stability of Na2NC AM was good after 3 months storage.

Bridged Bicyclo Compounds↗
PubMed1993

Pharmacokinetics of sustained-release tablets of metoprolol in Chinese.

Single and repeated oral doses pharmacokinetic studies of metoprolol sustained-release tablets (Sino-Swed Pharmaceutical Co Ltd) were performed on 12 Chinese healthy subjects in an open randomized crossover manner, using metoprolol tablets from Sweden Astra International Pharmaceutical Co Ltd as control. Drug concentrations in plasma were assayed by gas chromatography-electron-capture detector method. The percent of drug absorbed in vivo at 1, 2, 4, 6, 8 h correlated well with the amount of drug released in vitro at corresponding time (P > 0.05). Pharmacokinetic parameters in Chinese after metoprolol tablets were comparable to the reported data in foreigners.

Administration, Oral↗
PubMed1993

Pharmacokinetics and relative bioavailability of lomefloxacin preparations in 10 healthy Chinese volunteers.

The pharmacokinetics of lomefloxacin tablet and capsule were determined following a single oral dose of 400 mg given to each of 10 Chinese healthy male volunteers in an open, randomized crossover study. Drug concentrations in plasma were assayed by HPLC method. The peak levels in plasma averaged 6.0 +/- 1.3 and 5.9 +/- 1.0 micrograms.ml-1 at 1.3 +/- 0.4 and 1.2 +/- 0.4 h, and the areas under the drug concentration curves were 43 +/- 15 and 44 +/- 13 h.micrograms.ml-1 for lomefloxacin tablet and capsule, respectively. The concentration-time courses after medication conformed to a 1-compartment open model with a first order absorption. Pharmacokinetic parameters after tablet did not differ significantly from the corresponding values after capsule. The bioavailability of tablet was comparable to that of capsule.

Adult↗
PubMed1993

[Effect of thymic factor D on lipid peroxide, glutathione, and membrane fluidity in liver of aged rats].

The effects of thymic factor D (TFD) on aging were investigated in male Wistar rats at the age of 24 months. Thymic factor, polypeptides extracted from swine thymus, was given to aged rats in the dose of 2 mg.kg-1 sc every other day for 3 months. It was shown that TFU decreased the content of malondialdehyde (MDA) and lipofuscin in the liver of aged rats, accompanied by an increase of glutathione (GSH). Besides, the declined fluidity of hepatic mitochondrial and microsomal membranes in aged rats was recovered to the level of young adult rats by administration of TFD. It is suggested that TFD may possess beneficial effects on retarding the senile metabolic changes in hepatic cells.

Aging↗
PubMed1993

Localization of mRNAs representing collagenase and TIMP in sections of healing human burn wounds.

Interstitial collagenase, a matrix metalloproteinase, is known to be actively involved in remodeling of cutaneous tissues including those affected by trauma, neoplasia, and inflammation. Conversely, collagenase activity is blocked by tissue inhibitor of metalloproteinases (TIMP). Because both collagenase and TIMP are rapidly secreted into the extracellular matrix, their sites of synthesis remain ambiguous. To determine the site and sequence of collagenase and TIMP expression in cutaneous wound repair, we examined partial and full thickness excisions of human burn wounds representing days 2 to 34 postinjury. Prominent labeling for collagenase and TIMP was detected in epithelial cells at the burn margin and at the edges of surviving hair follicles and eccrine sweat structures in the wound bed. Within the dermis, cells expressing collagenase and TIMP were at first perivascular in location and later appeared at the interface zone between viable and nonviable dermis. A diversity of cell types including macrophages, fibroblasts, endothelial cells, and keratinocytes appeared to express mRNAs for collagenase and TIMP. Little if any labeling was detected in necrotic regions, in adjacent nonwounded dermis, or epidermis. Our data indicate that collagenase and TIMP are temporally and spatially regulated during cutaneous wound repair.

Adolescent↗
PubMed1993

[Study on cisplatin albumin microspheres for neck external artery embolization].

In this paper the technique of emulsion chemical-crosslinking was used to prepare cisplatin albumin microsphere for jaw squamous cancer by neck external artery embolization. It was yellow powder with yield 80 +/- 5%, mean size 56.3 microns, cisplatin concentration 14.02-14.20%, loading rate 97.08-97.95%. The release characteristics in vitro, sterilization, stability and recipe of disperse solvent of cisplatin albumin microsphere were investigated. Animal test showed that cisplatin albumin microsphere may plug the branches of neck external artery well and remain in local tissue.

Animals↗
PubMed1993

[Study on 125I-labeled human chorinic gonadotropin after purification through gel electrophoresis].

Radioiodination of HCG with 125I Na using chloramine-T is widely employed. However, 125I-HCG damages in storage and thus results in decrease of immunological and biological activities. When 125I-HCG was in store as long as 30 days, the immunological activity and biological activity decreased from 100% to 33.1% and 44.0%, respectively. We used polyacrylamide gel electrophoresis to purify 125I-HCG which had been kept in store for 30 days since radiolabeling, and we found the binding capacities of purified 125I-HCG increased. The combination rates of purified 125I-HCG with antibody and receptors accounted for 90.5% and 95.3% of those of 125I-HCG 1 day after radiolabeling. These results suggest that 125I-HCG which has been stored for a period since radiolabeling should be purified before use.

Chorionic Gonadotropin↗
PubMed1993

[Prevention of reserpine induced experimental gastric ulcer in rat with amoxicillin a report of preliminary controlled study].

In recent years, amoxicillin (A) has been proved very effective in clearing helicobacter pylor (HP) and promoting ulcer healing. Is the cure due solely to the clearance of HP? Forty three Wistar rats were randomized into four groups to investigate the efficacy of A in preventing the experimental ulcer induced by reserpine and compare it with that of ranitidine (R) and antacid weishuping (W). A normal saline (NS) group was used as control. The total numbers of ulcer induced per rat for the NS, W, R and A groups were 7.8 +/- 5.1, 2.2 +/- 3.2, 1.0 +/- 1.2 and 2.1 +/- 1.9, respectively. The ulcer indices were 20.8 +/- 13.2, 4.5 +/- 7.7, 2.0 +/- 3.7 and 4.5 +/- 3.9, respectively. No HP was identified. The results indicated that A, R and W were all effective in preventing reserping induced ulcer with no significant difference (P > 0.05); they were significantly more effective than NS (P < 0.05). Since A is not an antacid and no HP existed in the experimental rats, there must be a mechanism of A involved in the prevention of experimental ulcer.

Amoxicillin↗
PubMed1993

[Cordyceps sinensis in protection of the kidney from cyclosporine A nephrotoxicity].

To explore the protective effect of cordyceps sinensis (CS) on cyclosporine A nephro-toxicity (CsA-Nx) and the possible mechanism, we studied the kidney changes induced by CsA in rats by light microscopy (LM), electronic microscopy (EM) and morphometrical analysis. At the 15th day after receiving CsA, prominent vacuolation and necrosis were noted microscopically in proximal tubular cells and mitochondria swelling electronmicroscopically. Morphometrical study showed that the epithelial areas of both proximal and distal tubules in the CS group were larger than those of the control group. There were obvious vacuolation (90%) and necrosis in proximal tubular cells at different stages of chronic CsA-Nx. Interstitial edema with mild fibrosis was observed. Mitochondria abnormality was seen electronmicroscopically. Morphometrical analysis showed that the epithelial cell areas of tubules and glomeruli were smaller in the CsA group than those in the CS group. Both acute and chronic experiments showed that CS could protect the kidney from CsA-Nx and ameliorate the glomerular and interstitial injuries.

Animals↗
PubMed1993

Evidence on secretion of epidermal growth factor by the esophageal mucosa in humans.

Luminal release of esophageal epidermal growth factor (EGF) into the perfusing solutions (saline, HCl, and HCl/pepsin), aspirated with the newly developed esophageal perfusion catheter, was measured in 20 healthy volunteers (12 male, 8 female; mean age 40 yr; range 30-56 yr). A potential salivary contamination was excluded by a complete seal (with two balloons) of perfused esophageal segment and by a simultaneous, carefully monitored, collection of saliva. The concentration of EGF in each of 16 fully recovered 2-min perfusion samples was measured by RIA kit (Amersham, IL). The concentration of EGF in recovered NaCl perfusate varied between (mean +/- SEM) 1.78 +/- 0.19 and 2.14 +/- 0.14 ng/ml, whereas output varied between 9.25 +/- 0.98 and 11.14 +/- 0.82 ng/min. During perfusion with HCl, both the concentration of EGF within the esophageal perfusate and its secretion declined significantly to a value of 0.68 +/- 0.17 ng/ml (p < 0.0001) and 3.56 +/- 0.90 ng/min (p < 0.0001), respectively. Introduction of pepsin into an acidic perfusion solution (0.5 mg/ml of HCl) resulted in a significant increase in EGF concentration (1.99 +/- 0.36 ng/ml; p < 0.001) and output (10.24 +/- 1.84; p < 0.01), compared with EGF values recorded during perfusion with HCl. EGF output, calculated from a sealed 7.5-cm segment of the esophagus, was 10.39 +/- 0.89 ng/min, and was maintained at a steady state throughout an entire saline perfusion procedure. We present evidence that human esophageal mucosa has an enormous EGF secretory potential. The rapid esophageal EGF secretory response to intraluminal challenge with aggressive factors implies its role in the maintenance of the mucosal integrity.

Adult↗