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Biomedical subjects

Q Liu

Publications and source records attributed to Q Liu.

At least 595 records · Page 33Linked to original sources
PubMed1996

Cataract free zone and primary health care approach to prevention of blindness in Shunyi county of Beijing.

OBJECTIVE: To establish a three-level eye care network, together with a referral and monitor system for the prevention of blindness, with the aim of creating a cataract free zone. SUBJECTS AND METHODS: Shunyi County with a population of 548364 was chosen as the target site. Our activities included (1) establishment of a County Guiding Committee for the prevention of blindness: (2) training local ophthalmologists and primary eye care personnel: (3) extensive publicity of knowledge for the prevention of blindness: (4) screening for blindness and low vision, (5) cataract surgery as the chief measure for creating a cataract free zone. RESULTS: A referral and monitor system for cataract blindness was established in 1987. Seven local ophthalmologists, 449 primary eye care health workers and six optometrists were trained. 815 cataract-blind patients were identified. Up to December 1991, 667 patients (737 eyes), accounting for 81.84% of the total, were treated with cataract surgery, 90.64% of these eyes had their sight restored, and 59.66% patients resumed work. A cataract free zone has been created in Shunyi County. CONCLUSIONS: The prevention of blindness with cataract surgery as the chief measure can dramatically decrease the prevalence of blindness in a relatively short period of time.

Blindness↗
PubMed1996

[Determinations of antiovarian antibodies and cellular immunity functions in patients with premature ovarian failure].

OBJECTIVE: To investigate the variations of cellular immunity function and its relationship with antiovarian antibodies (AOAb) in patients with premature ovarian failure (POF). METHODS: Serum AOAb, T-lymphocyte subsets and leukocyteprocoagulant activity (LPCA) to ovarian antigens of peripheral blood were examined in 30 normal women (control group) and 30 patients with POF (POF group). RESULTS: The mean serum AOAb level in POF group was significantly higher than that in control group (6.80 +/- 1.9 kU/L vs 1.39 +/- 0.72 kU/L, P < 0.01). The percentage of CD3+, CD4+ cells increased significantly (65.42 +/- 5.31% and 44.79 +/- 5.90%, respectively), the percentage of CD8- cells was significantly lower (25.63 +/- 4.26%) and the ratio of CD4+/CD8+ increased (1.66 +/- 0.27) in POF group when compared with control group (P < 0.01). The positive rate of AOAb in patients who had elevated ratio of CD4+/CD8+ was significantly higher than those with normal CD4+/CD8+ ratio (85.7%, 18/21 vs 3/9; P < 0.01). The level of LPCA was elevated in POF patients with positive AOAb, and was correlated positively with the level of AOAb (chi 2 = 8.378, P < 0.01). CONCLUSIONS: These data showed that cellular immunity and humoral immunity to ovarian antigens can be concurrently produced in POF patients, and suggested that pathogenesis of POF may be associated with immune factors.

Adult↗
PubMed1996

[Factors affecting survival of hepatic carcinoma patients and their clinical significance].

UNLABELLED: 621 patients with unresectable hepatocellular carcinoma were given more than 2 times of intervention treatment. The correlations between the survival rates, tumor histology, portal tumor thrombus and the method and frequency of intervention treatment were analyzed. RESULTS: (1) The survival rates were higher in cases with single nodular tumor than in those with diffuse-tumors. (2) The survival rates of cases without tumor thrombus in portal system were significantly higher than those with tumor thrombus. However, no correlation was found between the survival rates and the location of thrombus in portal vein. (3) Intraarterial drug infusion combined with lipoidol plus gelatin sponge embolization gave the best therapeutic resalts. (4) How frequent was the intervention would be determined by the patients' general condition and was dependent on the quality of treatment. The cumulative survival rates were greatly affected by the above-mentioned factors. The treatment needs to be individualized.

Adult↗
PubMed1996

[Epidermal growth factor receptor expression in laryngeal cancer].

The expression of epidermal growth factor receptor (EGFR) in 60 laryngeal carcinoma and 20 normal laryngeal mucosa was studied with immunohistochemical LSAB (labelled streptavidin biotin) method to elucidate its role in tumor progression. EGFR was negative in all 20 normal laryngeal mucosa specimens, and it was positive in 44 of 60 laryngeal carcinoma specimens. The expression of EGFR did not correlate with tumor location, tumor stage and lymph node metastasis, but correlated significantly with histological grading and the survival rate. A significantly higher positive rate was found in poorly differentiated than in moderately well differentiated tumors. The 3-year survival rate in patients with expression of EGFR was much lower than those with negative results (P < 0.01). The results suggest that EGFR may play an important role in the process of carcinogenesis in laryngeal mucosa and be used as a useful marker for the assessment of biological behavior and prognosis of laryngeal carcinoma.

Adult↗
PubMed1996

A population-based study of lens opactities.

PURPOSE: Age-related lens opacity is the main cause of vision disability in elderly population all over the world. This study was designed to investigate the prevalence and incidence of lens opacity. METHODS: 1817 eyes of 932 adults over 45 years-old were sampled randomly from 4 villeges within Doumen, a county located in the south of Guangdong provience, China. The procedure of the examination was performed by ophthalmologists. The lens opacities were graded according to a standarized photo of the Lens Opacities Classification System II (LOCS-II). RESULTS: The prevalence of lens opacities in nuclear color, nuclear opacity, cortical opacity and subcapsular opacity was 16.1%, 28.6%, 30.3% and 8.7%, respectively. The frequency of all four types of opacities increased with age. The prevalence of lens opacities in four types was higher in female than that in male. CONCLUSION: The data we got are important for prevalence of lens opacities of population-based study as well as basic information for cohort study in the future.

Aged↗
PubMed1996

The etiology of vision impairment in target population.

PURPOSE: research the etiology of vision impairment in target persons over 45 years old in Doumen county, Guangdong province. METHODS: Depending on the prevalences of the blindness among the person aged over 50 years, the theoretic sample rate is 1,000/4,8733 x 100% = 2.05%. The 8 districts were divided into 3 parts according to the local economic situation and the proportion of the population in the areas. In fact, the sampling rate is 932/10055 = 88.34%. RESULTS: We found that impairment < 0.3 accounted for 10.94%. The prevalence of bilateral blindness and low vision was 1.61% and 3.22%, respectively. Both prevalences of blindness and low vision were increased with age. The leading cuase of blindness was cataract (45.2%). The second was corneal opacity (16.7%). Prevalences of the low vision and the blindness were higher in females than in males (P < 0.005). CONCLUSIONS: Curable and preventable diseases were the leading cause for the blindness (70%). Prevalences of blindness and the low vision increase with age. We will continually follow up the population over 50 years of age in Doumen county.

Age Factors↗
PubMed1996

[Chemical constituents of Ligusticum brachylobum Franch].

From the roots of Ligusticum brachylobum, which is used as a substitute for traditional Chinese medicine Radix Peucedani in the southwest of China, 5 compounds were isolated and identified as umbelliferone, selinidin, anomalin, nodakenin and ferulic acid.

Apiaceae↗
PubMed1996

[Chemical constituents of Aralia fargesii Franch].

From the EtOH extract of Aralia fargesii, 8 compounds were isolated and identified as umbelliferone, esculetin, scopoletin, scoparone, oleanic acid, falcarindiol, mellissic acid and beta-sitosterol.

Apiaceae↗
PubMed1995

Synergistic regulation of human beta-globin gene switching by locus control region elements HS3 and HS4.

Proper tissue- and developmental stage-specific transcriptional control over the five genes of the human beta-globin locus is elicited in part by the locus control region (LCR), but the molecular mechanisms that dictate this determined pattern of gene expression during human development are still controversial. By use of homologous recombination in yeast to generate mutations in the LCR within a yeast artificial chromosome (YAC) bearing the entire human beta-globin gene locus, followed by injection of each of the mutated YACs into murine ova, we addressed the function of LCR hypersensitive site (HS) elements 3 and 4 in human beta-globin gene switching. The experiments revealed a number of unexpected properties that are directly attributable to LCR function. First, deletion of either HS3 or HS4 core elements from an otherwise intact YAC results in catastrophic disruption of globin gene expression at all erythroid developmental stages, despite the presence of all other HS elements in the YAC transgenes. If HS3 is used to replace HS4, gene expression is normal at all developmental stages. Conversely, insertion of the HS4 element in place of HS3 results in significant expression changes at every developmental stage, indicating that individual LCR HS elements play distinct roles in stage-specific beta-type globin gene activation. Although the HS4 duplication leads to alteration in the levels of epsilon- and gamma-globin mRNAs during embryonic erythropoiesis, total beta-type globin mRNA synthesis is balanced, thereby leading to the conclusion that all of the human beta-locus genes are competitively regulated. In summary, the human beta-globin HS elements appear to form a single, synergistic functional entity called the LCR, and HS3 and HS4 appear to be individually indispensable to the integrity of this macromolecular complex.

Animals↗
PubMed1995

Carrier frequency of the IVS4 + 4 A-->T mutation of the Fanconi anemia gene FAC in the Ashkenazi Jewish population.

Fanconi anemia (FA) is a genetically and phenotypically heterogeneous autosomal recessive disorder defined by a cellular hypersensitivity to DNA cross-linking agents. One of the FA genes, FAC, has been cloned and the genomic structure of the coding region has been characterized. We have developed amplification refractory mutation system (ARMS) assays for five known mutations in FAC, and have applied these assays to determine the carrier frequency of the IVS4 + 4 A-->T (IVS4) mutation in an Ashkenazi Jewish population. We tested 3,104 Jewish individuals, primarily of Ashkenazi descent, for the two most common FAC mutations, IVS4 and 322delG. Thirty-five IVS4 carriers were identified, for a carrier frequency of 1 in 89 (1.1%; 95% confidence interval 0.79% to 1.56%); no 322delG carriers were found. To determine if the IVS4 mutation was confined to the Ashkenazi Jewish population, we tested 563 Iraqi Jews for IVS4, and no carriers were found. Because the IVS4 mutation has only been found on chromosomes of Ashkenazi Jewish origin and is the only FAC mutation found on these chromosomes, we suggest that a founder effect is responsible for the high frequency of this mutation. With a carrier frequency greater than 1% and simple testing available, the IVS4 mutation merits inclusion in the battery of tests routinely provided to the Jewish population.

Base Sequence↗
PubMed1995

Non-uniform distribution of cellular phenotypes in the optic tectum of the leopard frog.

Regional specialization in the retina have been described in a number of species. We have investigated whether such specializations can be found in the optic tectum, an area of the brain responsible for the processing of visual information. Using the tectum of Rana pipiens, we have examined the distribution of three different cell types defined on the basis of their immunoreactivity to somatostatin, substance P, and serotonin antibodies. These three immunoreactive cell populations had differing, nonuniform distributions in the optic tectum. Somatostatin-line immunoreactive cells were largely restricted to the caudal one-third of the tectum, whereas both substance P-like immunoreactive (SP-ir) and serotonin-like immunoreactive (5-HT-ir) cells were found unequally represented throughout the tectum. The percentage of SP-ir cells decreased significantly in both the posterior and medial directions from its high in the anterior lateral tectum. Although serotonin-like immunoreactivity was also greatest in the lateral tectum and decreased significantly medially, it was largely constant in the anterior-to-posterior dimension. The populations of SP-ir and 5-HT-ir cells were nonoverlapping. Our results suggest that information may be processed differently in different regions of the optic tectum.

Animals↗
PubMed1995

Identification of a new acute phase protein.

We have previously reported mouse SIP24 protein as a secreted inducible protein produced by quiescent Balb/c 3T3 cells. SIP24 can be produced in response to many factors, including serum, basic fibroblast growth factor, prostaglandin F2 alpha, phorbol ester, and dexamethasone. Here we present evidence to show that SIP24 is the product of mouse 24P3 mRNA. The 24P3 cDNA was originally cloned from an SV40-transformed quiescent mouse primary kidney cell culture, and it has been classified as a new member of the lipocalin protein family. We show that the SIP24/24P3 protein and mRNA increase dramatically in mouse serum and liver during the acute phase response induced by turpentine injection. Injection of mice with dexamethasone caused a modest increase of SIP24/24P3 mRNA in the liver. Tissue distribution studies revealed that SIP24/24P3 is mainly expressed in liver during the acute phase response. SIP24/24P3 was also detected in the brain and the uterus. In mouse BNL (Balb/c normal liver) cells, the production of SIP24/24P3 is stimulated by tumor necrosis factor alpha, which is a major regulator of the expression of other acute phase proteins. From its pattern of regulation, we conclude that SIP24/24P3 is a new type 1 acute phase protein.

3T3 Cells↗
PubMed1995

High-level expression of functional rat neuronal nitric oxide synthase in Escherichia coli.

The neuronal nitric oxide synthase (nNOS) has been successfully overexpressed in Escherichia coli, with average yields of 125-150 nmol (20-24 mg) of enzyme per liter of cells. The cDNA for nNOS was subcloned into the pCW vector under the control of the tac promotor and was coexpressed with the chaperonins groEL and groES in the protease-deficient BL21 strain of E. coli. The enzyme produced is replete with heme and flavins and, after overnight incubation with tetrahydrobiopterin, contains 0.7 pmol of tetrahydrobiopterin per pmol of nNOS. nNOS is isolated as a predominantly high-spin heme protein and demonstrates spectral properties that are identical to those of nNOS isolated from stably transfected human kidney 293 cells. It binds N omega-nitroarginine dependent on the presence of bound tetrahydrobiopterin and exhibits a Kd of 45 nM. The enzyme is completely functional; the specific activity is 450 nmol/min per mg. This overexpression system will be extremely useful for rapid, inexpensive preparation of large amounts of active nNOS for use in mechanistic and structure/function studies, as well as for drug design and development.

Amino Acid Oxidoreductases↗
PubMed1995

Enzymes of B-ring-deoxy flavonoid biosynthesis in elicited cell cultures of "old man" cactus (Cephalocereus senilis).

Elicited cell cultures of the cactus Cephalocereus senilis produce a group of flavonoids with unsubstituted B-rings, including an aurone which represents a new class of phytoalexin. Preliminary enzymological studies indicated that the chalcone synthase (CHS) and chalcone isomerase (CHI) from cultures of C. senilis were active with cinnamoyl-CoA and 2',4',6'-trihydroxychalcone, respectively, probable intermediates for synthesis of flavonoids with unsubstituted B-rings. We now demonstrate that the cultures contain two isoforms of CHI, both of which are induced by elicitor treatment and are active with both 2',4,4',6'-tetrahydroxy- and 2',4',6'-trihydroxychalcone. (Hydroxy)-cinnamate:CoA ligase in the cactus cultures was active with cinnamic, 4-coumaric, caffeic, ferulic, and 4-methoxycinnamic acids, but not sinapic acid. A single form of CoA ligase, as resolved by chromatofocusing analysis, was active against both cinnamate and 4-coumarate. Cinnamic acid 4-hydroxylase (CA4H) activity was induced by elicitor treatment. Thus, elicited cultures contain the necessary enzymatic activities for synthesis of B-ring-hydroxy and -deoxy flavonoids. Synthesis of only the deoxy class in response to elicitation may result from some form of metabolic compartmentation through which the CA4H reaction is bypassed, leading to formation of cinnamoyl CoA which may then be incorporated into B-ring deoxy flavonoids via nondiscriminating CHS and CHI activities.

Acyltransferases↗
PubMed1995

Involvement of SOX proteins in lens-specific activation of crystallin genes.

We have studied the mechanism of delta 1-crystallin gene activation, which occurs early in lens cell differentiation, and have previously shown that an essential element of the delta 1-crystallin enhancer is bound by a group of nuclear factors, delta EF2, among which delta EF2a is highly enriched in lens cells. In this report we show that the cDNA of delta EF2a codes for the chicken SOX-2 protein (cSOX-2), which is structurally related to the sex-determining factor SRY. Sox-2 is expressed at high levels in the early developing lens in both chicken and mouse embryos. Overexpression of delta EF2a/cSOX-2 increased delta 1-crystallin enhancer activity to a plateau in lens cells, but not in fibroblasts, consistent with the previously drawn conclusion that delta EF2a activates transcription only in concert with another factor present in the lens. This result supports the model that SOX proteins act as architectural components in the activating complex formed on an enhancer, as indicated for another HMG domain protein, lymphoid enhancer binding factor 1 (LEF-1). We also show that SOX protein binding is essential for lens-specific promoter activity of the mouse gamma F-crystallin gene. This work is the first to show delta- and gamma-crystallin genes as examples of direct regulatory targets of SOX proteins and provides evidence that diversified crystallin genes are regulated, at least partly, by a common mechanism.

Amino Acid Sequence↗