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Biomedical subjects

Z Lin

Publications and source records attributed to Z Lin.

At least 217 records · Page 12Linked to original sources
PubMed1998

[A computer system for bone age measurement of hand radiographs].

OBJECTIVE: This study was to development a computer system for assessing bone age which would analyse children's growth level accurately and quickly. METHODS: It used the standards of estimating skeletal maturity for Chinese (CHN) scoring method to assess the bone age of Chinese children. We applied image enhancement techniques for imprving the quality of the hand-wrist radiographs, while an automated system was developed to implement this method. RESULTS: Users could get a clear and reliable radiograph through image processing, compare each bone of the hand-wrist radiograph with that of the scanned image of the standard radiographs, then generate the stage of bone maturity. The computer would give out individual and total bone score and a value of bone age. CONCLUSION: This system implemented evaluation of bone age rapidly and accurately, it would help orthodontist to choose the best time of treatment.

Age Determination by Skeleton↗
PubMed1998

[Research of ultrasonic emulsifying and drawing away technique on biological tissue].

Technique of ultrasonic emulsifying and drawing away on biological tissue can achieve the purpose of operating treatment. Having the aid of ultrasonic wave technique, it transforms electronic energy into kinetic energy of high frequency mechanical vibration. Making use of the function of stronger instantaneous shock acceleration more than the minium cutting threshold of biological tissue, it cuts biological tissue pathologically changed and not needed, then smashes and emulsifies it, draws away the emulsified tissue by pump system.

Equipment Design↗
PubMed1998

[Synthesis and vasodilative activities of benzamide derivatives].

Twenty two benzamide derivatives were synthesized of which twenty one were not reported before. Vasodilative activity screening in vitro has shown that most of the compounds possess various activities, among which compound H1, H11, H17, E1, E3 demonstrated a superior pharmacological profile to the lead compound when inhibiting effect on the noradrenaline (10(-7) mol.L-1) induced contraction of rat aortic strip was chosen as the evaluation criterion, while H7,15, E7 exerted significant inhibiting action toward 85.7 mmol.L-1 KCl induced contraction of rat aortic strip. Further evaluation assays for their KCO potentials showed that E1 might be an ATP sensitive KCO. Preliminary structure-activity relationships of this kind of aromatic amides are discussed herein.

Animals↗
PubMed1998

[The distribution of nitric oxide synthetase in Vcx and its relation with the expression of FOS induced by teeth movement in rats].

It was studied the central role of nitric oxide(NO) during experimental teeth movement and the relation between nitric oxide synthetase (NOS) positive neurons and FOS like immunoreactivity (FLN) with the NADPH-diaphorase histochemistry and immunocytochemical reaction method. Results indicated that NOS positive neurons and FLN showed typical distribution in Vcx and there was some overlap between them. It suggests that NO is involved in the central modulation of the stimulating message of teeth movement, and which further explains the central modulation mechanism of experimental teeth movement in rats.

Animals↗
PubMed1998

[Isolation, purification and identification of metallthionein from strain BD 101 of Saccharomyces cerevisiae].

Selection of Saccharomyces cerevisiae BD101 having resistance to metal ions and producing metallothionein by inducer from Saccharomyces. These proteins were isolated and purified by Sephadex G-50 and subsequent DEAE Sepharose CL-4B, then Sephadex G-25 for desalination. There were two iso-MTs for Cu-induced. The, molecular weights were 7 kD and had 60 amino acids. Both Cu-MTs were rich in Cysteine (10%). 4 atom Cu/6 mole Cys/mole Cu-MTs.

Amino Acids↗
PubMed1998

[Observation of the effect of pediatric secondary posterior-chamber intraocular lens implantation].

PURPOSE: To evaluate the effects of secondary posterior chamber lens implantation for aphakia in children. METHODS: Thirty-six consecutive pediatric aphakic eyes were retrospected. All eyes were secondarily implanted posterior-chamber lens using different operative techniques according to the condition of lens capsule remained after dissecting the posterior adhesion, forming extent space in posterior chamber. Follow-up ranged from 1 to 20 months. The effect of corrected visual acuity was observed. RESULTS: Postoperative nated visual acuity was equal or better than corrected visual acuity preoperatively in 22 eyes(61.1%). Postoperative corrected visual acuity was better than that before surgery in 32 eyes (88.8%) and was equal to that before surgery in 4 eyes(11.1%). CONCLUSIONS: Secondary posterior chamber IOLs implantation was an effective surgery for aphakic eyes in children, but attention should be paid to anti-inflammatory treatment and amblyopia treatment.

Amblyopia↗
PubMed1998

Effect of cataract surgery on ocular axial length elongation in young children.

PURPOSE: To evaluate the influence of cataract surgery on eyes of children between 1-5 years old. MATERIALS AND METHODS: Forty-seven cases of pediatric cataract, including 31 cases of bilateral congenital cataract and 16 cases of unilateral posttraumatic cataract, were retrospected. Of the 31 cases of congenital cataract, 19 cases (group 1) had undergone cataract extraction with intraocular lens (IOL) implantation, 12 (group 2) had undergone cataract extraction without IOL implantation. Each of them had their two eyes operated separately at an interval of 1 year or longer. Of the 16 cases of posttraumatic cataract, 6 (group 3) had undergone cataract extraction with IOL implantation and 10 (group 4) had undergone cataract extraction without IOL implantation. Mean age at the time of interested surgery was 2.9 years (range from 1.1 to 5.1 years). Ocular axial length of both eyes measured by A-scan ultrasonography before and after the surgery of the earlier operated eye in the congenital groups and the operated eye in the post-traumatic groups was recorded. The elongation of axial length of the earlier operated eye in the congenital groups and the operated eyes in the posttraumatic groups of each case were compared with that of the fellow eye statistically with paired t-test. RESULTS: The mean follow-up was 2.6 years (ranged from 1.0 to 6.4 years). In all the 4 groups, the elongation of axial length between the earlier operated eye and later operated eye in the congenital groups and between the operated and unoperated eyes in the posttraumatic groups of each case was not significantly different (p > 0.05). CONCLUSION: Cataract surgery, either extraction with or without IOL implantation, did not retard axial elongation in children above 1 year old.

Age Factors↗
PubMed1997

Codon usage and nucleotide composition in Coxiella burnetii.

Coxiella burnetii, the causative agent of Q fever, is an obligate intracellular bacterium. With the development of molecular biology techniques, there have been increasing efforts on gene cloning and other genetic analyses of this organism. In this report, we tabulate the codon usage (CU) and nucleotide (nt) co-occurrence in C. burnetii, based on available nt sequence data. The average G+C content of the C. burnetii genome is 42.4%, where the G+C content is 42.7% for the chromosome and 38.7% for the plasmid. In comparison to Escherichia coli, there is biased CU. Some codons are frequently used in C. burnetii, but rarely used in E. coli and vice versa. Plasmid genes prefer A or T at the first or third position of a codon. However, TAA remains the most used stop codon. In the AT-rich DNA of C. burnetii, A or T tend to occur together, forming A or T tracks.

Bacterial Proteins↗
PubMed1997

Phorbol esters alter the morphology of cultured guinea-pig myenteric glia via a protein kinase C-independent mechanism.

Cultures of myenteric ganglia from adult guinea-pigs were used to study the influence of neuroactive substances on glial cells by monitoring changes in their morphology. The following substances had no effect on glial morphology: adenosine, ATP, carbachol, glutamate, bradykinin, isoprenaline, prostaglandin E2, sodium nitroprusside and lipopolysaccharide. The only substances found to affect glial morphology were phorbol esters, and in particular phorbol 12-myrisate 13-acetate (PMA), which acted at the nM range. Glial cells, which were normally polygonal, assumed a stellate shape within 30-60 min after the addition of PMA. Protein kinase C (PKC) inhibitors did not block this effect, and PKC activators did not mimic it. The effect of PMA was also not mediated by changes in the intracellular concentrations of either Ca2+, H+ or cyclic AMP. Dye coupling among glial cells was blocked by PMA. The phorbol ester-mediated effect on glial structure may have profound influence on neuronal organization and function.

Animals↗
PubMed1997

Increased sarcolemmal glucose transporter abundance in myocardial ischemia.

Many clinical and laboratory studies suggest that an increase in glucose uptake and metabolism by ischemic myocardium helps protect myocardial cells from irreversible injury. We have examined whether increased sarcolemmal abundance of cardiomyocyte glucose transporters plays a role in this adaptive response. We have shown that acute myocardial ischemia in perfused rat hearts results in increased sarcolemmal abundance of the major glucose transporter, GLUT4, by causing translocation of GLUT4 molecules from an intracellular compartment to the sarcolemma. In nonischemic control hearts only 18 +/- 2.8% of GLUT4 molecules were on the sarcolemma whereas in ischemic hearts this increased to 41 +/- 9.3%. Insulin also caused translocation of GLUT4 molecules to the sarcolemma, and resulted in 61 +/- 2.6% of GLUT4 molecules on the sarcolemma. The combination of ischemia and insulin did not result in additive increases in sarcolemmal GLUT4 abundance. In more persistent or chronic ischemia, the other major myocardial glucose transporter, GLUT1, appears to play an important role. The mRNA for this transporter, which is constitutively expressed on cardiomyocyte sarcolemma, was increased 2.0-fold in regions of hibernating myocardium in humans with coronary heart disease as well as in persistently hypoxic rat neonatal cardiomyocytes in primary culture. In neither of these conditions was GLUT4 mRNA expression increased. Thus, acute myocardial ischemia increases sarcolemmal glucose transporter abundance mainly by translocating previously synthesized GLUT4 molecules from an intracellular compartment, whereas more chronic ischemia also increases GLUT1 abundance via enhanced mRNA expression. Increased GLUT1 and GLUT4 abundance may participate in the augmented glucose uptake of ischemic myocardium and therefore may help protect ischemic myocardium from irreversible injury.

Animals↗
PubMed1997

The contribution of inflammatory mediators and nitric oxide to lipopolysaccharide-induced intussusception in mice.

Intussusception is a major cause for intestinal obstruction in children. Its etiology is unclear, but it is often associated with some kind of infection. We have developed a model for intussusception in mice using intraperitoneal (IP) injection of lipopolysaccharide (LPS). The objective of this study was to identify the putative mediators that participate in this LPS-induced intussusception. LPS (12 mg/kg) was injected into adult mice (N = 52) and 6 hr later, 25% of the animals demonstrated intussusception in the small or large intestine. We next tested whether nitric oxide (NO) or various inflammatory mediators contributed to this effect: Indomethacin (10 mg/kg) injected with LPS (12 mg/kg) completely prevented the effect of LPS (N = 20). The tumor necrosis factor (TNF) blocker pentoxifylline (200 mg/kg) significantly reduced the incidence of intussusception to 6.6% (N = 30). The platelet-activating factor (PAF) antagonist BN52021 (10 and 20 mg/kg) reduced the incidence of intussusception to 13.3% in both doses (N = 15 for each dose). Addition of 2% arginine (NO precursor) to the drinking water 36 hr before the injection of LPS increased the incidence of intussusception to 30.7% (N = 32). In mice injected with the NO synthase inhibitor L-NAME (20 mg/kg) only 3.8% developed intussusception (N = 26). Our results indicate that the induction of intussusception by LPS proceeds via parallel pathways involving cytokines, prostaglandins, and NO. Our previous pathological study showed that LPS did not cause any changes that may act as a lead point for the intussusception, suggesting that LPS induced intussusception by altering gut motility. We therefore propose that these mediators combine to induce disturbed gut motility that results in the formation of intussusception.

Animals↗
PubMed1997

Increased immune responses to regenerating partial liver grafts in the rat.

The relationship between liver regeneration and the induction of the immune response is uncertain. We hypothesize that the altered environment of the regenerating liver allograft increases the immune response to the allograft. In DA (RT1a) to LEW (RT1I) rats, hepatectomized, small-for-size and whole, normal-for-size liver transplants were performed. Naive and 70% hepatectomized LEW served as controls. Animals were assessed for survival, mass restoration, and host alloresponses. Although 30% partial allografts regenerated well to achieve a volume nearly equal to that of recipient's native liver in 7 days, survival was significantly shorter than that of the recipients of whole grafts (8.8 +/- 0.4 vs 10.3 +/- 1.2 days, n = 6, P < 0.02). When compared on Day 4 after transplantation, histologic examination revealed a more vigorous cellular infiltration in the sinusoidal area in the partial liver transplant group. Phenotypic analysis of thymocytes showed a predominance of more mature phenotypes in the partial group, including more prominent decrease in the frequency of CD4, CD8-double-positive cells and increase in that of alpha beta TCRhigh cells. Proliferative activity of thymocytes in response to Con A was higher in the partial group than in the whole group. MLR of splenocytes against donor-type antigens was higher in the partial group, whereas reactivity against third party was the same as in other groups. These data suggest that host cellular responses to the allograft are enhanced in the regenerating, small-for-size liver graft. These findings have implications in the clinical management of liver recipients with damaged or small for size livers.

Animals↗
PubMed1997

Classification of normal and abnormal electrogastrograms using multilayer feedforward neural networks.

A neural network approach is proposed for the automated classification of the normal and abnormal EGG. Two learning algorithms, the quasi-Newton and the scaled conjugate gradient method for the multilayer feedforward neural networks (MFNN), are introduced and compared with the error backpropagation algorithm. The configurations of the MFNN are determined by experiment. The raw EGG data, its power spectral data, and its autoregressive moving average (ARMA) modelling parameters are used as the input to the MFNN and compared with each other. Three indexes (the percent correct, sum-squared error and complexity per iteration) are used to evaluate the performance of each learning algorithm. The results show that the scaled conjugate gradient algorithm performs best, in that it is robust and provides a super-linear convergence rate. The power spectral representation and the ARMA modelling parameters of the EGG are found to be better types of the input to the network for this specific application, both yielding a percent correctness of 95% on the test set. Although the results are focused on the classification of the EGG, this paper should provide useful information for the classification of other biomedical signals.

Algorithms↗
PubMed1997

Quantitative assessment of whole body galactose metabolism in galactosemic patients.

We employed [1-13C] galactose in isotope kinetic studies to delineate whole body galactose metabolism in vivo in patients with galactose-1-phosphate uridyltransferase (GALT) deficiency. The data in three control and three adult galactosemic subjects, homozygous for the most common GALT gene defect, the Q188R mutation, and with absent RBC GALT activity, revealed an apparent endogenous galactose synthesis rate of 0.53-1.05 mg/kg per hour. Unlike normal children and adults who eliminated 3%-6% and 21%-47% of an intravenous bolus of [1-13C] galactose as 13CO, in expired air in 1 and 5 h respectively, classic galactosemic patients, either Q188R/Q188R or Q188R/unknown, released almost none in 1 h and 3%-6% in 5 h. In contrast, an African-American galactosemic variant patient with a S135L/S135L mutation and no residual RBC GALT activity oxidized [1-13C]galactose to 13CO2 at a rate comparable to control subjects. Individuals homozygous for the Duarte mutation, N314D/N314D and Q188R/ N314D. Q188R/+ and S135L/+ subjects also had normal breath test results. Not surprisingly, the Q188R/Q188R classic galactosemic patient cannot handle an acute galactose load, failing to match a control subject in the rapid conversion of [1-13C]galactose to [13C]glucose and 13CO2. However, classic patients synthesize substantial quantities of galactose de novo and on a lactose-free diet must oxidize comparable amounts of galactose to maintain steady-state levels of galactose and galactose metabolites such as galactose-1-phosphate, galactitol and galactonate. In vivo isotope kinetic analyses may allow us to understand better these aspects of galactose metabolism and, through the use of studies in variant galactosemics, perhaps allow us to begin to unravel the pathophysiology of galactosemia.

Adolescent↗
PubMed1997

Species identification based on the point mutations of histo-blood group ABO genes by PCR-RFLP and direct sequencing.

Using the PCR-restriction fragment length polymorphism (RFLP) and direct sequencing methods, 181 bp DNA fragments at the ABO blood group locus of human and eight different primates were examined. Through PCR amplification and digestion of the product with Hha-1 restriction enzyme, each of the amplified fragments of human, chimpanzee and green monkey was cut into two fragments of 147 and 34 bp, and the corresponding fragment of the other primates was digested into three fragment of 115, 34 and 32 bp. The 181 bp fragments of chimpanzee and green monkey were digested with Mva-1 into three fragments of 82, 58 and 41 bp, and 69, 58 and 54 bp, while the fragments of human and the other primates were separated into two fragments of 123 and 58 bp. Thus, using Hha-1 and Mva-1, human PCR-amplified product of a part of the ABO gene could be discriminated from those of the other primates examined. In addition, by direct sequencing of the 181 bp DNA fragment, two Mva-1 recognition sites and one Hha-1 recognition site were found in the fragments of chimpanzee and green monkey, one Mva-1 site and one Hha-1 site were detected in humans, and one Mva-1 site and two Hha-1 sites in the other primates. These results corresponded well with the data of PCR-RFLP. This method has a good potential for species identification at the DNA level.

ABO Blood-Group System↗
PubMed1997

Fine mapping of the MLK-3 gene within 11q13 and its exclusion as the MEN1 susceptibility gene.

MLK-3 kinase is a widely expressed serine/ threonine kinase that bears multiple protein interaction domains and regulates signals mediated by the stress-responsive pathway. Thus, MLK-3 signaling affects numerous cellular processes, raising the possibility that MLK-3 might play a role in oncogenesis. In this report, we describe the fine mapping of the MLK-3 gene within the 11q13.1 chromosomal region. By integrating data from somatic cell hybrids and double color fluorescence in situ hybridization on metaphase chromosomes and DNA fibers. MLK-3 has been assigned approximately 1 Mb telomeric of PYGM, close to the D11S546 locus. Since the MEN1 susceptibility locus is also located within the 11q13.1 region, we have carried out Southern and Northern blot analyses, as well as protein truncation assays to establish whether abnormalities in MLK-3 lead to the development of this familial cancer syndrome. Our observations exclude MLK-3 as the MEN1 gene.

Animals↗
PubMed1997

Association of p53 protein expression in stage I lung adenocarcinoma with reference to cytological subtypes.

Since the nuclear accumulation of p53 protein is known to correspond well with mutation of the p53 tumor-suppressor gene, we analyzed the p53 protein immunohistochemically with the anti-p53 mouse monoclonal antibody, DO-7, in 105 stage I lung adenocarcinomas. The p53 immunoreactivity was detected in the nuclei of cancer cells in 51 cases (49%). The p53-positive cases had a significantly poorer prognosis compared with the p53-negative cases (log-rank test; P < .001) When p53 expression was compared among the cytological subtypes of adenocarcinoma, the incidence of p53 expression in the bronchial surface epithelial cell type (11 of 15) was significantly higher than in the goblet cell type (1 of 6) and tended to be higher than the Clara cell/alveolar type II pneumocyte type (27 of 59). These findings indicate that immunohistochemical examination of the p53 protein is a potential prognostic factor in stage 1 lung adenocarcinomas, and that p53 expression has been associated with the cytological subtype.

Adenocarcinoma↗