Biomedical subjects

H Liu

Publications and source records attributed to H Liu.

1,271 records · Page 71Linked to original sources

PubMedDate not supplied

Representing information in patient reports using natural language processing and the extensible markup language.

OBJECTIVE: To design a document model that provides reliable and efficient access to clinical information in patient reports for a broad range of clinical applications, and to implement an automated method using natural language processing that maps textual reports to a form consistent with the model. METHODS: A document model that encodes structured clinical information in patient reports while retaining the original contents was designed using the extensible markup language (XML), and a document type definition (DTD) was created. An existing natural language processor (NLP) was modified to generate output consistent with the model. Two hundred reports were processed using the modified NLP system, and the XML output that was generated was validated using an XML validating parser. RESULTS: The modified NLP system successfully processed all 200 reports. The output of one report was invalid, and 199 reports were valid XML forms consistent with the DTD. CONCLUSIONS: Natural language processing can be used to automatically create an enriched document that contains a structured component whose elements are linked to portions of the original textual report. This integrated document model provides a representation where documents containing specific information can be accurately and efficiently retrieved by querying the structured components. If manual review of the documents is desired, the salient information in the original reports can also be identified and highlighted. Using an XML model of tagging provides an additional benefit in that software tools that manipulate XML documents are readily available.

Humans↗

PubMedDate not supplied

Changes in phospholipids and free fatty acids in the brains of mice preconditioned by hypoxia.

Changes in the composition and contents of phospholipids and free fatty acids were observed and compared in three groups: (A) unpreconditoned normal controls, (B) exposure to 1 run of hypoxia and (C) exposure to 4 runs of hypoxia. In group B, the content of phosphatidyl ethanolamine (PE), phosphatidyl serine (PS) and free fatty acids (FFAs) increased significantly and the content of phosphatidyl choline (PC) and sphingomyelin (SM) decreased significantly. While in group C the content of PE, PS, PC and FFAs changed significantly when compared with that of group B, all phospholipid (except SM) and FFA contents tended to decrease to the level of group A. No new FFA was seen in the brain homogenates in any of the three groups. These results suggest that the changes in the content of mouse brain phospholipids and FFAs may be adaptive and involved in the animals' tolerance to hypoxia.

Animals↗

PubMedDate not supplied

Cellular delivery of human CNTF prevents motor and cognitive dysfunction in a rodent model of Huntington's disease.

The delivery of ciliary neurotrophic factor (CNTF) to the central nervous system has recently been proposed as a potential means of halting or slowing the neural degeneration associated with Huntington's disease (HD). The following set of experiments examined, in detail, the ability of human CNTF (hCNTF) to prevent the onset of behavioral dysfunction in a rodent model of HD. A DHFR-based expression vector containing the hCNTF gene was transfected into a baby hamster kidney fibroblast cell line (BHK). Using a polymeric device, encapsulated BHK-control cells and those secreting hCNTF were transplanted bilaterally into rat lateral ventricles. Eight days later, the same animals received bilateral injections of quinolinic acid (QA, 225 nmol) into the previously implanted striata. A third group received sham surgery (incision only) and served as a normal control group. Bilateral infusions of QA produced a significant loss of body weight and mortality that was prevented by prior implantation with hCNTF-secreting cells. Moreover, QA produced a marked hyperactivity, an inability to use the forelimbs to retrieve food pellets in a staircase test, increased the latency of the rats to remove adhesive stimuli from their paws, and decreased the number of steps taken in a bracing test that assessed motor rigidity. Finally, the QA-infused animals were impaired in tests of cognitive function-the Morris water maze spatial learning task, and the delayed nonmatching-to-position operant test of working memory. Prior implantation with hCNTF-secreting cells prevented the onset of all the above deficits such that implanted animals were nondistinguishable from sham-lesioned controls. At the conclusion of behavioral testing, 19 days following QA, the animals were sacrificed for neurochemical determination of striatal choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) levels. This analysis revealed that QA decreased striatal ChAT levels by 35% and striatal GAD levels by 45%. In contrast, hCNTF-treated animals did not exhibit any decrease in ChAT levels and only a 10% decrease in GAD levels. These results support the concepts that implants of polymer-encapsulated hCNTF-releasing cells can be used to protect striatal neurons from excitotoxic damage, produce extensive behavioral protection as a result of that neuronal sparing, and that this strategy may ultimately prove relevant for the treatment of HD.

Animals↗

PubMedDate not supplied

Comparative study of barnidipine and felodipine in Chinese patients with essential hypertension.

This study evaluated the efficacy and safety of barnidipine for the treatment of mild-to-moderate essential hypertension in Chinese patients. A total of 131 patients were randomized to receive either barnidipine (10 -15 mg) or felodipine (5 - 10 mg) once daily for 4 weeks. Both drugs reduced blood pressure significantly, with > or = 87% of patients obtaining a marked or moderate effect. The mean +/- SD reductions in systolic and diastolic blood pressure were 19.2 +/- 13.6 and 14.4 +/- 7.0 mmHg, respectively, for barnidipine treatment, and 20.3 +/- 11.3 and 14.7 +/- 7.7 mmHg, respectively, for felodipine treatment. There were no significant differences between the two drugs in terms of anti-hypertensive effect, heart rate, laboratory test results or incidence of adverse events. More patients taking felodipine experienced palpitations, but this difference was not statistically significant. Barnidipine is as efficacious and safe as felodipine in the treatment of essential hypertension in Chinese patients.

Adult↗

PubMedDate not supplied

Histopathologic fundamentals of acquired laryngeal stenosis.

Acquired laryngeal stenosis is the most serious long-term complication of endotracheal intubation in children. Employing the whole-organ serial section technique, the sequence of histopathologic changes leading to stenosis was studied. Ulceration occurs when an endotracheal tube causes mechanical abrasion and/or induces pressure necrosis on the laryngeal mucosa. Secondary healing of ulceration produces granulation tissue and subsequent fibrous scar tissue. Most exuberant granulation tissue resolves without sequelae, but some becomes firm, almost avascular fibrous scar tissue. The accumulation of submucosal fibrous tissue may decrease the size of the glottic or subglottic lumen. Contraction of scar tissue causes a distortion of glottic and subglottic laryngeal complex, leaving a reduced and irregularly shaped glottic and subglottic lumen. Submucosal mucous gland hyperplasia directly reduces the inner diameter of the airway. Finally, compromise of the laryngeal lumen may occur when the duct of a mucous gland is obstructed by scarring resulting from intubation: mucus accumulates in the dilated duct, producing a ductal cyst.

Child↗

PubMedDate not supplied

Effect of iron chelator, hydroxyl radical scavenger and cytochrome P450 inhibitors on the cytotoxicity of cisplatin to tumor cells.

BACKGROUND: Iron catalyzed reactive oxygen metabolites (ROM) are important mediators in cisplatin (CP)-induced nephrotoxicity, and cytochrome P450 (CYP) is the major source of this iron. Iron chelators, hydroxyl radical scavengers and CYP inhibitors have shown marked protection. MATERIAL AND METHODS: This study was designed to determine whether these agents affect the tumoricidal efficacy of CP to LLC-WRC 256 tumor cells. RESULTS: CP was cytotoxic to the tumor cells in a dose and time dependent manner. Iron chelator, hydroxyl radical scavenger and CYP inhibitors did not reduce the cytotoxic effect of CP. Exposure of the tumor cells to CP did not increase the catalytic iron release and the generation of hydroxyl radical. Both CYP activity and content in the tumor cells were less than 10% of that in the rat liver. CONCLUSION: We speculate that iron chelator, hydroxyl radical scavenger and CYP inhibitors do not alter the antitumor efficacy of CP.

Animals↗

PubMedDate not supplied

Analysis of flavonoids in Semen Cuscutae by micellar electrokinetic chromatography and high-performance liquid chromatography.

Five different flavonoids in Semen Cuscutae were determined for the first time by micellar electrokinetic chromatography (MEKC) and reversed-phase high-performance liquid chromatography (RP-HPLC). MEKC was carried out on a 68.5-cm fused-silica capillary using 0.035 mol/L sodium dodecyl sulfate and 0.02 mol/L borate-phosphate (pH 7.0) containing 10% methanol as the running buffer. RP-HPLC was performed on a 12.5-cm Hypersil C18 (Agilent Technologies, Palo Alto, CA, U.S.A.) column with a 0.025-mol/L phosphate acid (A) - methanol (B) solvent gradient. Both MEKC and HPLC are rapid, simple, and efficient. The results obtained using these techniques are compared. MEKC and HPLC can be complementary to each other for the quality control of Semen Cuscutae.

Calibration↗

PubMedDate not supplied

Hepatitis B Catch-Up Project: analysis of 1999 data from the Chicago Public Schools.

PURPOSE: Asian American Pacific Islander (AAPI) children face an increased risk for acquiring hepatitis B virus infection. Since 1990, the Centers for Disease Control and Prevention have recommended universal hepatitis B immunization for AAPI children. In 1997, Illinois passed a law requiring hepatitis B vaccination for school entry, but its implementation was restricted to pre-kindergarten and fifth-grade students. That same year, the Illinois Health Education Consortium (IHEC) began the Hepatitis B Immunization Catch-Up Project in collaboration with the Chicago Public Schools (CPS) and community organizations. Schools targeted for IHEC intervention were those enrolling more than 100 (or over 20%) AAPI students. This study describes the effects of the Illinois law and the Hepatitis B Immunization Catch-Up Project on hepatitis B immunization of AAPI students in the CPS in 1999. METHODOLOGY: The effects of the IHEC Catch-Up Project intervention and the Illinois law upon hepatitis B immunization was tested using a two-way analysis of variance for the 1999-2000 cohort of AAPI students enrolled in the CPS as of November 1999. PRINCIPAL FINDINGS: Results indicated students required to receive hepatitis B immunization shots received a significantly (p < .001) higher mean number of shots than was the case for students who were not required to receive the shots. Similarly, IHEC-intervention students received a significantly (p < .001 ) higher mean number of shots than was the case for students who were not part of the IHEC intervention. CONCLUSIONS: The IHEC intervention produced a significant, positive effect on the hepatitis B immunization rate above and beyond the state law. The practical significance of the IHEC intervention is described and discussed.

Analysis of Variance↗

PubMedDate not supplied

[Cloning and characterization of a chromosome-encoded catechol 2,3-dioxygenase gene from Pseudomonas aeruginosa ZD 4-3].

Catechol 2,3-dioxygenase (C23O), one of extradiol-type dioxygenases cleaving the aromatic C-C bond at the meta-position of dihydroxylated aromatic substrates, catalyzes the conversion of catechol to 2-hydroxymuconic semialdehyde. Based on curing experiment, PCR identification, and Southern hybridization, the gene responsible for C23O was localized on a 3.5-kb EcoRI/BamHI fragment and cloned from P. aeruginosa ZD 4-3 able to degrade both single and bicyclic compounds via the meta-cleavage pathway. A complete nucleotide sequence analysis of the C23O revealed that it had one ORF, which showed a strong amino acid sequence similarity to the known C23Os of mesophilic gram-negative bacteria. The alignment analysis indicated that distinct difference existed between the C23O in this study and the 2,3-dihydroxybiphenyl dioxygenases cleaving bicyclic aromatic compounds. The heterogenous expression of the pheB gene in Escherichia coli BL21(DE3) demonstrated that this C23O possessed a meta-cleavage activity.

Amino Acid Sequence↗

PubMedDate not supplied

Synergistic effect of macrophage activation and immune serum, especially IgG2, on resistance to infection with Treponema pallidum ssp. endemicum in hamsters.

Experimental studies have indicated that macrophages are involved in the pathogenesis of syphilis. Whether macrophages alone or with immune serum are ultimately responsible for killing of treponemes is disputed. We have demonstrated that BCG-vaccinated hamsters administered normal serum contained fewer treponemes in the inguinal and popliteal lymph nodes than did the nonvaccinated controls. When BCG-vaccinated hamsters were injected with syphilitic immune serum and challenged with Treponema pallidum ssp. endemicum, treponemicidal activity was enhanced. Treponemicidal activity was also detected in BCG-vaccinated hamsters challenged with treponemes treated in vitro with immune serum and its immunoglobulin fractions, especially IgG2. The immune IgG2 fraction had more treponemicidal activity than did the immune IgG1 fraction and the unfractionated immune serum. Our observations indicate an important synergistic role for macrophages and immune serum, especially IgG2, for elimination of T. pallidum ssp. endemicum from the host.

Adult↗

PubMedDate not supplied

Velocity measurements within confined turbulent jets: application to cardiovalvular regurgitation.

An expression for centerline mean velocity distributions for circular and noncircular confined turbulent jets has been obtained by assuming self-preservation of flow downstream of the jet potential core. It was assumed that the velocity decay was not only dependent on the streamwise distance x in terms of x/d, as in the case of free jets, but also on the ratio of the orifice diameter d to the confining pipe diameter D. To validate the expression and to determine the empirical constants, measurements of the centerline velocities within the confined jets issuing from different size circular orifices and various noncircular orifices of different shapes were conducted. The results indicate that the validity of the expression is restricted to d/D < or =0.25 and is weakly dependent on the particular orifice shape. It is suggested that, as for the case of free turbulent jets reported earlier, that this expression may be used potentially to predict the valvular lesion size or to estimate the volume of valvular regurgitation for confined jets provided the value of D, which corresponds to the "atrial diameter," is known or statistically available.

Adult↗