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Biomedical subjects

C Liu

Publications and source records attributed to C Liu.

At least 613 records · Page 34Linked to original sources
PubMed1996

Intraocular pressure changes after peribulbar injections with and without ocular compression.

AIM: Two prospective studies were carried out in order to investigate (1) the rise in intraocular pressure (IOP) following peribulbar anaesthesia with a fixed volume of anaesthetic agent administered by a single surgeon, and (2) the efficacy of ocular compression with the Honan balloon for lowering IOP. Glaucomatous eyes were excluded from both studies. METHODS: In study group 1, 36 eyes of 36 patients undergoing cataract and/or implant surgery each received peribulbar injections consisting of 5 ml of anaesthetic from an inferotemporal site through the conjunctiva and a further 5 ml from a medial injection through the caruncle. IOP values were measured immediately before and after the injections and then after a variable period of external ocular compression. In study group 2, 20 eyes of 20 patients undergoing cataract surgery received peribulbar injections of local anaesthetic as above. IOP values were measured immediately before and after the injections and after 20 minutes without ocular compression. After a further 20 minute period with ocular compression the IOP was again measured. RESULTS: In study group 1, the mean immediate rise in IOP induced by the injections was 11.44 (95% confidence interval 8.97-13.90) mm Hg. The mean change in IOP after ocular compression was an overall fall of 2.42 (0.49-4.34) mm Hg from the pre-injection value. In study group 2, the mean injection induced rise in IOP was 9.45 (6.90-12.00) mm Hg. The mean fall in IOP during the first 20 minutes without ocular compression was 2.85 (1.20-4.50) mm Hg. During the second 20 minutes with ocular compression the mean fall in intraocular pressure was 11.05 (8.14-14.96) mm Hg. CONCLUSIONS: There is a large and individually variable rise in IOP following peribulbar anaesthesia. Ocular compression with the Honan balloon is effective in reversing this rise even when the initial rise is large.

Anesthesia, Local↗
PubMed1996

Nature's knockout: the Mel1b receptor is not necessary for reproductive and circadian responses to melatonin in Siberian hamsters.

The pineal hormone melatonin regulates seasonal reproduction and influences the timing of circadian rhythms. The Mel1a and Mel1b receptors are the high-affinity melatonin receptors present in mammals. Unexpectedly, the Mel1b receptor gene of the Siberian hamster, Phodopus sungorus, cannot encode a functional receptor; two nonsense mutations are present within the coding region. Southern blot analysis indicates that this is a single copy gene. The Mel1b receptor gene is nonfunctional in outbred populations of P. sungorus and Phodopus campbelli. Siberian hamsters lacking a functional Mel1b receptor nevertheless show seasonal reproductive and circadian responses to melatonin, indicating that the Mel1b receptor is not necessary for these responses. These data support the hypothesis that the Mel1a receptor, which does encode a functional receptor in this species, mediates reproductive and circadian responses to melatonin.

Amino Acid Sequence↗
PubMed1996

Observation of curative effect of acupuncture therapy plus scalp acupuncture for restoring consciousness and inducing resuscitation in 80 cases of acute apoplexy.

During our 4-year work in The Republic of Yemen, the authors used acupuncture therapy to restore consciousness and induce resuscitation plus scalp acupuncture in 80 cases of acute apoplexy, with 63 cases cured, accounting for 78.75%. This therapy is obviously superior to the traditional principle of point selection in acupuncture used in 25 cases as to curative effect, treatment course and other aspects. There is an obvious statistical difference (P < 0.005).

Acupuncture Therapy↗
PubMed1996

13C-methacetin breath test parameter S for liver diseases diagnosis.

The mechanism of 13C-methacetin breath test is set forth clearly with the analysis of pharmacokinetics mode, and the measuring method of 13C-methacetin breath test and its clinical applications in the diagnosis of liver diseases are reported in detail. On the basis of comprehensive analysis of the clinical test data, the advanced diagnostic parameter S is of important significance for the application and development of breath test.

Acetamides↗
PubMed1996

The allele frequency distribution at VNTR locus D17S5 (YNZ22) in a Japanese population sample.

The allele frequencies for the YNZ22 locus were determined in a Japanese population sample (n = 164) using the polymerase chain reaction (PCR). We observed 10 alleles and 39 genotypes. Allele distributions in our data showed a different pattern from those reported in the literature for European Caucasians. No deviation from Hardy-Weinberg equilibrium was found. The observed heterozygosity was 83.5%. In Japan the YNZ22 is one of useful genetic markers for paternity testing and identify testing, with a chance of exclusion (CE) value of 68% and a power of discrimination (PD) value of 89%.

Alleles↗
PubMed1996

The role of the therapeutic contact lens in the management of recurrent corneal erosions: a review of treatment strategies.

PURPOSE: Recurrent corneal erosion is a commonly encountered condition for which multiple treatment modalities are suggested. We discuss the role of the therapeutic contact lens in the management of this condition. METHODS: We reviewed treatment strategies based on published literature and on personal experience. RESULTS: Ocular lubricants are the standard treatment for recurrent corneal erosion. Where loose flaps of epithelium are present, they should be removed before prescribing lubricants. In some dystrophic cases, reduplicated basement membrane can be scraped off before lubricant treatment is resumed. Where conservatives measures fail, three treatment modalities may be employed: application of a therapeutic contact lens; anterior stromal puncture; and excimer laser phototherapeutic keratectomy (PTK). The choice of treatment is determined by: etiology; location of disease (axial or off-axis); coexisting ocular diseases; individual patient reliability; and availability of equipment. The therapeutic contact lens has a role in the management of difficult post-traumatic cases where the lesion is axial. The use of such a lens in dystrophic cases is often not very effective, and these cases may be most effectively treated with PTK. If a contact lens is used, the lens should be fit fairly tight and both physician and patient should be aware of the risk of microbial keratitis. CONCLUSIONS: The guidelines in this paper should enable physicians to maximize success and minimize risks when managing patients with recurrent corneal erosions.

Contact Lenses↗
PubMed1996

Allele distribution of a VNTR polymorphism at D4S43 locus in the Japanese population.

Allele frequencies for the VNTR locus D4S43 were determined in a Japanese population sample by the polymerase chain reaction. Nine different alleles containing 1-15 repeats of the basic 14 bp unit were observed in 156 unrelated Japanese. The most common allele was one repeat unit (62.82%), and the next common alleles were those with 11 (14.42%) and 7 repeat units (12.50%). We estimated that D4S43 locus has a heterozygosity index of 0.56, a mean exclusion chance of 0.32, a discrimination rate of 0.76, and a polymorphic information content of 0.52. No evidence of significant deviations from the Hardy-Weinberg equillibrium was found in the Japanese population data.

Alleles↗
PubMed1996

Automated DNA typing of ACTBP2: a comparison of allelic ladder with GS 2500 as internal marker.

A comparison was made between the size values of the alleles measured by the internal size marker of Genescan (GS 2500) and the size values measured by an allelic ladder constructed by our laboratory in the application of Genescan software for the typing of the ACTBP2 system. The measurement by GS 2500 showed a greater than 2 bp divergence (SD = 0.893) while the measurement by the allelic ladder showed only 0.1 bp divergence (SD = 0.008). Thus in genotyping of ACTBP2 by Genescan software, the method presented here of using the allelic ladder as the size marker instead of GS 2500 is easier and more reliable.

Alleles↗
PubMed1996

Baculovirus-mediated expression and characterization of rat CYP2A3 and human CYP2a6: role in metabolic activation of nasal toxicants.

Cytochrome P450 2A3 (CYP2A3) was previously identified in rat lung by cDNA cloning and recently found to be expressed at a high level in the olfactory mucosa. In the current study, CYP2A3 was expressed in insect cells lacking endogenous cytochrome P450 (P450) activity, and the substrate specificity of the recombinant cytochrome was characterized and compared with that of CYP2A6, a human ortholog of rat CYP2A3, which has been detected in human olfactory mucosa as well as in liver. The CYP2A3 and CYP2A6 cDNAs were cloned into baculovirus, and recombinant viruses were used to produce active enzymes in Spodoptera frugiperta (SF9) cells. The metabolic activities of S. frugiperta cell microsomal fractions containing CYP2A3 or CYP2A6 were studied in a reconstituted system with purified rabbit NADPH-P450 reductase. CYP2A3 was found to be active toward testosterone, producing 15 alpha-hydroxytestosterone and several other metabolites, but it had only low activity toward coumarin. On the other hand, CYP2A6 was active toward coumarin but not toward testosterone. However, both enzymes were active in the metabolic activation of hexamethylphosphoramide, a nasal procarcinogen, and 2,6-dichlorobenzonitrile (DCBN), a herbicide known to cause tissue-specific toxicity in the olfactory mucosa of rodents at very low doses. In addition, both enzymes were active toward 4-nitrophenol, a preferred substrate for CYP2E1. Consistent with CYP2A3 being a major catalyst in microsomal metabolism of DCBN, the activities of both CYP2A3 and rat olfactory microsomes in DCBN metabolism were inhibited strongly by metyrapone and methoxsalen (ID50 < 1 microM, with DCBN at 30 microM), but only marginally by 4-methylpyrazole, an inhibitor of CYP2E1. In contrast, the activity of CYP2A6 was only weakly inhibited by metyrapone or methoxsalen (ID50 > 50 microM). Thus, rat CYP2A3 and human CYP2A6 have differences in substrate specificity as well as tissue distributor. These findings should be taken into account when assessing the risk of exposure to potential nasal toxicants in humans.

Animals↗
PubMed1996

High level expression of oryzacystatin in Escherichia coli.

A rice cDNA library of immature seeds has already been constructed, from which colonies carrying oryzacystatin cDNA were isolated. The coding region of the oryzacystatin (a thiol proteinase inhibitor) gene was amplified by the Polymerase Chain Reaction (PCR) and inserted downstream of lambdaPRPL promoter of E. coli thermal-inducible expression vector pBV220. An oryzacystatin expression plasmid pBVC9 was therefore obtained. Shifting the culture temperature of E. coli DH5 alpha (pBVC9) from 30 degrees C to 42 degrees C led to a high level expression of oryzacystatin. The result of SDS-PAGE showed a distinct band of 12.0 kDa which accounts for at least 10% of the total soluble proteins. The inhibitory activity of the total soluble proteins of E. coli DH5 alpha (pBVC9) toward papain was confirmed by using that of E. coli DH5 alpha (pBV220) as a control.

Cloning, Molecular↗
PubMed1996

[Fingerprinting varieties of foxtail millet using probe gFM31].

Fifty-nine genotypes (landraces, varieties or breeder's lines) of foxtail millet (Setaria italica Beauv.) were used in DNA fingerprinting with a highly polymorphic probe, xPSF31. Fifty-eight types were distinguished, with only two genotypes giving identical band patterns. DNA sequencing of xPSF31 did not reveal any relationship with mini-or micro-satellite sequences. The probe revealed only weak signals in genomic DNA from other cereal species, wheat, barley, maize, rice, and pearl millet, indicating that xPSF31 is a Setaria genus specific sequence.

Base Sequence↗
PubMed1996

Transgenic mice containing the human erythropoietin receptor gene exhibit correct hematopoietic and neural expression.

The erythropoietin receptor (EpoR), known for its role in the proliferation and differentiation of erythroid cells, has been detected in nonhematopoietic tissues. We have reported previously that in addition to hematopoietic expression, EpoR is expressed at high levels in embryonic mouse brain and decreased to nondetectable levels by birth. While using transgenic mice to characterize human EpoR expression, we observed that a 15-kb human EpoR transgene (expressed in hematopoietic tissues but at a reduced level) also exhibited in the embryonic brain low levels of expression that persisted through adulthood. To examine further the basis of tissue and developmental specificity of the human EpoR gene, we produced additional transgenic mice using an 80-kb human EpoR genomic fragment isolated from a P1 phagemid human library. We found that this transgene is expressed appropriately in hematopoietic tissues (including yolk sac, fetal liver, adult spleen, and bone marrow) at levels comparable to the endogenous murine EpoR. The 80-kb transgene also provided high-level expression in the embryonic brain that paralleled the levels of the endogenous murine EpoR and was no longer detectable after birth. These data suggest that the high level of embryonic brain expression may be relevant to the human EpoR gene and that the transgenic mouse with an 80-kb fragment is a suitable model for studying the regulation and possible functional importance of human EpoR expression in the developing embryo.

Animals↗
PubMed1996

EGR-1, the reluctant suppression factor: EGR-1 is known to function in the regulation of growth, differentiation, and also has significant tumor suppressor activity and a mechanism involving the induction of TGF-beta1 is postulated to account for this suppressor activity.

The transcription factor EGR-1 is a potential regulator of over 30 genes and plays a role in growth, development, and differentiation and, in addition, has significant transformation suppression activity. The regulatory properties are reviewed and a hypothesis for the transformation suppression activity is proposed. EGR-1 contains three "zinc-finger" motifs in the C-terminal portion of the molecule that constitute the DNA-binding domain and interact with the promoters by virtue of two classes of GC-rich elements: single GC-elements (GCEs) with the consensus 5'-T-G-C-G-T/g-G/A-G-G-C/a/t-G-G/T-3' and overlapping sites consisting of an Sp-1 binding site and the GCE consensus or close homolog of these sequences. The Wilm's tumor suppressor gene product WT1 interacts with the same GCE and, owing in part to four alternate splice products, interacts with a broader range of GC-rich elements with the consensus 5'-GNGNGGGNG-3' and 5'-TCCTCCTCCTCCTC-3'. WT1 commonly but not invariably acts as repressor of transcription, whereas EGR-1, in the absence of overlapping Sp-1 binding sequences, is often an activator. The well-known rapid response of the EGR-1 gene following mitogenic stimulation together with the occurrence of GCEs in the promoters of many growth factors and protooncogenes suggests a role of EGR-1 in growth. Moreover, EGR-1 is constitutively expressed in several viral-transformed systems. On the other hand, studies of model and human tumor lines reveal that EGR-1 has significant growth and transformation suppression roles. Recent studies show that this effect can be accounted for by the ability of EGR-1 to induce the expression and secretion of TGF-beta1, a potent growth suppressor of many cell types, by binding to a single GCE of the TGF-beta1 promoter. Although the effects of EGR- at overlapping Sp1/EGR-1 DNA binding sites are not predictable, known cases fall into two loose groups. Sp1 is usually activating and increasing concentrations of EGR-1 lead to displacement that results in either inhibition of transactivation or EGR-1-dependent transactivation. Moreover, recent studies suggest that displaced Sp1 binds to and activates the endogenous Egr-1 gene, thereby leading to "facilitated inhibition" of Sp1 function by the resulting increased EGR-1. This effect may augment the growth suppressive function of EGR-1 based on induction of TGF-beta1.

Animals↗
PubMed1996

[Study on the level of soluble interleukin-2 receptor, expression of membrane interleukin-2 receptor and T lymphocyte subpopulations in pulmonary tuberculosis].

OBJECTIVE: To evaluate the significance of soluble interleukin-2 receptor (sIL-2R), membrane interleukin-2 receptor (mIL-2R) and T lymphocyte subpopulations in development of pulmonary tuberculosis. METHODS: The level of sIL-2R, expression of mIL-2R and the profile of T lymphocyte subpopulations in patients with pulmonary tuberculosis were tested by sandwiched ELISA and alkaline phosphatase-antialkaline phosphate (APAAP) methods. RESULTS: The levels of sIL-2R, CD8 were higher, and expression of mIL-2R, CD4, CD4/CD8 ratio were lower in pulmonary tuberculosis than those in normal controls (P < 0.001). And the changes of all indicators in patients with cavitation were more obvious than those in patients without (P < 0.001), the changes in progressive stage were more obvious than those in stable and improving stages (P < 0.001). CONCLUSION: The results indicated that the patients, condition and prognosis of pulmonary tuberculosis were related to the changes of sIL-2R level, mIL-2R expression and T lymphocyte subpopulations.

Adult↗