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Biomedical subjects

C Liang

Publications and source records attributed to C Liang.

At least 127 records · Page 7Linked to original sources
PubMed1997

[A survey on mother's nutritional knowledge-attitude on the feeding of young child in Guangdong province].

A survey on mother's nutrition knowledge-attitude on the feeding of young child was conducted in Guangdong province in 1995 among 414 mothers of 0 to 18 months old children. The results showed that the nutritional knowledge-attitude level of the mothers was low in both city and township. Only 51% of them had qualified level. The level of general nutritional concepts and the nutritional knowledge-attitude during weaning period were significantly lower than that of breastfeeding and follow-weaning. It suggests that the promotion of nutritional education in the feeding of young children is urgent in Guangdong province especially in township and rural area. It is necessary to focus on the improvement of nutritional knoweledge in weaning period and general nutrition concepts.

Breast Feeding↗
PubMed1997

Retinal toxicity of intravitreous octreotide in the rabbit.

OBJECTIVE: To evaluate the ocular toxicity of intravitreous octreotide. DESIGN: New Zealand white rabbits weighing approximately 2 kg were given 5 mg (group 1, two eyes), 2 mg (group 2, four eyes), 1 mg (group 3, four eyes), 0.5 mg (group 4, two eyes), 0.3 mg (group 5, two eyes) or 0.1 mg (group 7, two eyes) of octreotide acetate, two doses of 0.3 mg 1 week apart (group 6, four eyes) or 0.1 mL of balanced salt solution (group 8 [control group], two eyes). OUTCOME MEASURES: Findings on clinical examination and electroretinography, performed before and 10 days after injection, and on light microscopy. RESULTS: Cataracts developed in groups 1 and 2. No clinical changes were found in groups 3 to 8. Electroretinography showed various degrees of decrease in the b-wave amplitude in groups 1 and 2; the results were normal in groups 3 to 8. Histologic examination showed macrophage and monocyte infiltration in the vitreous and retina in group 1. No histologic change was seen in the eyes in groups 2 to 8. CONCLUSIONS: Octreotide injected intravitreally is safe at dosages of 1 mg or less.

Animals↗
PubMed1997

[Epidemiological study of external genital diseases in 5172 adolescents].

OBJECTIVE: To study the incidence of external genital diseases and the health status of external genitalia in male adolescents in china. METHODS: 5172 male adolescents aged 7-22 were sampled randomly to examine the diseases and health status of external genitalia. According to the diagnostic criteria in textbook Surgery (3rd edition), all examinations were carried out by urologists. RESULTS: The total incidence of redundant prepuce was 67.79%, phimosis 10.09%, varicocele 19.82%, hydrocele 0.87%, concealed penis 0.68%, cryptorchidism 0.39%. CONCLUSION: The health status of external genitalia in male adolescents is bad. Redundant prepuce and phimosis are common diseases. The examination of external genitalia should be carried out in the physical examination of admission. This study may provide the theoretical evidence for prevention and treatment of male external genital disease as well as the important data for study on andrology.

Adolescent↗
PubMed1996

Kinetics of substrate reaction in the course of hydroperoxide-mediated inactivation of cytochrome P450 1A1.

A schematic kinetic model is proposed for the hydroperoxide-mediated substrate reaction and cytochrome P450 inactivation. From the model, the relationships between the product concentration at infinite time (P infinity), the apparent rate constant of P450 inactivation (A), and the substrate concentrations are predicted, and the predictions were experimentally examined. The reciprocal of P infinity is proportional to the reciprocal of the substrate concentration in both CuOOH- and H2O2-supported substrate reactions. The reciprocal of P infinity is proportional to cumene hydroperoxide (CuOOH) concentration, but P infinity is independent of H2O2 concentration, indicating different effects of CuOOH and H2O2 in P450 inactivation. The apparent rate constant (A) is proportional to the reciprocal of the substrate concentrations, suggesting substrate protection of P450 from hydroperoxide inactivation. The model also suggests that a second CuOOH molecule may compete with substrate for binding to the P450 substrate binding site. Simulated kinetics of production formation vs time are quite consistent with the experimental kinetics.

Animals↗
PubMed1996

Ocular toxicity of intravitreous transforming growth factor-beta 1.

PURPOSE: To evaluate the ocular toxicity of intravitreous transforming growth factor-beta 1 (TGF-beta(1)). METHODS: Eyes of New Zealand white rabbits were injected intravitreally with TGF-beta(1) in doses of 20, 10, 5, 1 or 0.5 micrograms. Electroretinography and clinical examination were performed before and after the injection. At either 10 or 30 days after injection, the eyes were enucleated and examined histologically. The endothelium of fresh corneas, which had received 20 micrograms TGF-beta(1) or nothing, were checked 5 days after injection. RESULTS: Corneal opacity was caused by doses > or = 10 micrograms in 7 of 7 eyes; by doses of 5 micrograms in 3 of 4 eyes; and by doses of 1 microgram in 1 of 4 eyes. Doses > or = 5 micrograms also caused pannus formation in 15 of 16 eyes. Ten days after injection there was some decrease in B-wave amplitude on electroretinography. Thirty days after injection the electroretinographic responses had recovered, except in the eyes injected with 20 micrograms TGF-beta(1), which still showed a decrease in step 1. Histological examination of paraffin sections did not demonstrate significant change. Corneal thickness of the eyes receiving 20 micrograms TGF-beta(1) was twice that of the normal cornea and some corneal endothelial cells lost their hexagonal shape. CONCLUSION: TGF-beta(1) injected intravitreally at doses > or = 1 micrograms is toxic to the cornea. Retinal function is only slightly disturbed by 20 micrograms of TGF-beta(1).

Animals↗
PubMed1996

Scalable and expressive medical terminologies.

The K-Rep system, based on description logic, is used to represent and reason with large and expressive controlled medical terminologies. Expressive concept descriptions incorporate semantically precise definitions composed using logical operators, together with important non-semantic information such as synonyms and codes. Examples are drawn from our experience with K-Rep in modeling the InterMed laboratory terminology and also developing a large clinical terminology now in production use at Kaiser-Permanente. System-level scalability of performance is achieved through an object-oriented database system which efficiently maps persistent memory to virtual memory. Equally important is conceptual scalability-the ability to support collaborative development, organization, and visualization of a substantial terminology as it evolves over time. K-Rep addresses this need by logically completing concept definitions and automatically classifying concepts in a taxonomy via subsumption inferences. The K-Rep system includes a general-purpose GUI environment for terminology development and browsing, a custom interface for formulary term maintenance, a C+2 application program interface, and a distributed client-server mode which provides lightweight clients with efficient run-time access to K-Rep by means of a scripting language.

Artificial Intelligence↗
PubMed1996

[The effect of anisodamine hydrochloride on globin chain synthesis in anemic mice].

We treated anemic mice with Anisodamine hydrochloride followed by Hb electrophoresis and detection of globin chain synthesis rate. We found that the synthesis of their globin chains remarkably increased and would last for approximately 10 days, While the results did not show any generation of fetal Hb, possible effect of the drug might come from the raising of alpha and beta globin chains of the adult mice.

Anemia↗
PubMed1996

[Construction of the wt-p53 gene recombinant retroviral vector. Inhibiting the growth of laryngocarcinoma cell line].

We have constructed wt-p53 gene recombinant retroviral vector. The p53 cDNA with positive regulative sequence was subcloned into the Xho I site between the two LTRs of the N2A retroviral vector which contained the cytomegalovirus promotor/enhancer for expression and a neomycin resistance gene allowing G418 selection in reverse orientation and established the PA317 packaging cell line producing virus. The recipient cell line of Hep2 (laryngocarcinoma) containing the abnormal p53 gene was transfected in vitro with fresh retroviral stock produced. The result showed that the constructed wt-p53 gene recombinant retroviral vector was able to suppress growth of laryngocarcinoma cell in vitro. These observations indicate that recombinant retrovirus expressing wild-type p53 may be the useful vectors for gene therapy of human laryngocarcinoma.

DNA, Recombinant↗
PubMed1996

[Study of electrophysiological properties of large conductance K(+)-channels in outer hair cells from the guinea pig with patch-clamp technique].

The basic electrophysiological characteristics of large conductance K(+)-channels in the basolateral cell membrane of outer hair cells (OHC) from the guinea pig cochlea were studied with patch-clamp technique. Acutely isolated OHC preparations were obtained by enzymatic digestion and excised patches were made in cell-attached configuration to record single-channel currents led by patch-clamp micropipette and fed to patch-clamp amplifier. Data were sampled and analyzed on-line with a computer. The result showed that the typical properties of single channels of large conductance K(+)-channels were: 1. The channel was activated by depolarization of membrane and it showed a marked voltage-dependence. The channel had a unitary conductance of about 133 pS and the channel current reversed at about -30mV under asymmetrical K+ concentration gradient. 2. Tetraethylammonium (TEA, > 10 mmol/L), a potassium channel blocker, dose-dependently abolished the outward current. 3. The open probability (Po) and mean open time of this channel was markedly increased with elevation of cytoplasmic Ca2+ concentration. These results suggest that a population of voltage-dependent and Ca(2+)-activated K+ channel exists in the basolateral membrane of OHC of the guinea pig; it is characterized by a very high unitary conductance and high sensitivity to Ca2+ and is blocked by K+ channel blocker. This work provided valuable basic materials for further study on the regulation and drug influence of the type of single channels.

Animals↗
PubMed1995

ORC and Cdc6p interact and determine the frequency of initiation of DNA replication in the genome.

The origin recognition complex (ORC) binds replicators in the yeast S. cerevisiae in a manner consistent with it being an initiator protein for DNA replication. Two-dimensional (2D) gel techniques were used to examine directly initiation of chromosomal DNA replication in temperature-sensitive orc mutants. Unlike in wild-type cells, in orc2-1 and orc5-1 mutant cells, only a subset of replicators formed active origins of DNA replication at the permissive temperature. At the restrictive temperature, the number of active replicators was diminished further. Using a genetic screen, CDC6 was identified as a multicopy suppressor of orc5-1. 2D gel and biochemical analyses demonstrated that Cdc6p interacted functionally and physically with ORC. We suggest that ORC and Cdc6p form a prereplication complex at individual replicators and therefore cooperate to determine the frequency of initiation of DNA replication in the genome.

Cell Cycle Proteins↗
PubMed1995

A unique insertion in the S gene of surface antigen--negative hepatitis B virus Chinese carriers.

The presence of unique hepatitis B virus (HBV) variants has been investigated in two Chinese patients with chronic liver disease, whose sera were positive for HBV-DNA by dot blot hybridization or polymerase chain reaction (PCR) but hepatitis B surface antigen (HBsAg)-negative by conventional polyclonal antibody based immunoassays. PCR amplification of HBV-DNA followed by direct sequencing showed an insertion of six nucleotides, which introduced two additional amino acids between codons 122 and 123 in one patient (Isolate 1), whereas a nine nucleotide insertion in the other patient (Isolate 2) gave rise to three amino-acids between codons 123 and 124 immediately upstream from the 'a' determinant in the S gene. These insertions have not been described previously in any published sequences of the known subtypes and were absent from sequences of 30 HBsAg-positive Chinese patients from the same region. In the cases under study, the insertion is associated with four consecutive adenine molecules from nucleotides 516 to 519. It seems likely that this area is a hot spot for insertions in HBV. We found none of the previously described amino-acid deletions or substitutions in the pre-S1, pre-S2 and S genes, which are involved in unusual antigenic profiles. This finding suggests that genetic mutations in the S gene outside the 'a' determinant may be responsible for failure to detect HBsAg in some Chinese patients with chronic hepatitis caused by HBV infection.

Adult↗
PubMed1995

Structure and properties of a herpesvirus of turkeys recombinant in which US1, US10 and SORF3 genes have been replaced by a lacZ expression cassette.

In the process of generating an insertional mutant of herpesvirus of turkeys (HVT) expressing lacZ at the protein kinase (PK) locus, we isolated a recombinant which contained an intact PK gene but the short unique regions US1, US10 and SORF3 had been deleted and replaced by the lacZ cassette. Moreover, the virus contained duplicate copies of gD, gI and gE in an opposite orientation flanking lacZ, US2 and PK which were contiguous. These results are of interest in relation to the flexibility of the short unique segment (Us) and of the inverted repeats flanking Us of the alpha-herpesviruses. The recombinant expressed beta-galactosidase and was genetically stable in vitro and in vivo. Chickens inoculated with the virus developed antibodies to HVT antigens and to beta-galactosidase but the replication of the recombinant in vivo was impaired in comparison to parental HVT as shown by a reduction in the proportion of infected lymphocytes.

Animals↗
PubMed1995

[Expression of proliferating cell nuclear antigen (PCNA) in premalignant lesions of laryngeal epithelium].

It is important to study the proliferative activity of cells in the premalignant lesions of laryngeal epithelium. Using PC-10, an antibody to PCNA and a standard immunohistochemical staining, we examined 11 cases of simple hyperplasia of epithelium (SHE), 32 cases of atypical hyperplasia of epithelium (AHE) and 42 cases of laryngeal squamous cell carcinoma (LSCC) for expression of PCNA, a protein associated with DNA polymerase delta and DNA replication. The results revealed that the PCNA indices in SHE, AHE and LSCC were 9.57%, 27.33% and 68.05%, respectively. The PCNA indices were 13.79%, 30.84% and 39.94%, in the mild, moderate and severe AHE, respectively. There were significant differences among the SHE, AHE and LSCC. A good correlation was found among different degrees of AHE. The pattern and location of PCNA positive cells in the intraepithelium had diagnostic importance. PCNA might provide a useful tool for studying cell proliferation in situ under normal and pathological conditions.

Adult↗