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J C Lu

Publications and source records attributed to J C Lu.

13 recordsLinked to original sources
PubMed2001

Prolactin receptor heterogeneity: processing and signalling of the long and short isoforms during development.

During development, the fetus is exposed to prolactin activity from the placenta, as well as from the developing fetal pituitary. Distinct prolactin receptor isoforms, having different cytoplasmic domains generated by alternative splicing, are expressed as development proceeds at different levels in different organs. The "long" receptors are able to mediate transduction of all signals examined, in contrast with the "short" isoforms, whose truncated cytoplasmic domains are able to mediate a much smaller repertoire of signals and can act as dominant negatives. Our studies demonstrate that, although these forms share internalization mechanisms, the long form is internalized faster, resulting in more rapid down-regulation of this form. In order to examine the mechanisms by which prolactin may exert trophic effects on its target tissues during development, we have examined the signalling pathways through which prolactin binding to the long receptor regulates the transcription of cyclin D1. Our studies reveal the importance of the JAK/STAT (Janus kinase/signal transduction and activators of transcription) pathway, and the complexity of prolactin signalling to this promoter.

Animals↗
PubMed1999

A random coefficient degradation model with random sample size.

In testing product reliability, there is often a critical cutoff level that determines whether a specimen is classified as "failed." One consequence is that the number of degradation data collected varies from specimen to specimen. The information of random sample size should be included in the model, and our study shows that it can be influential in estimating model parameters. Two-stage least squares (LS) and maximum modified likelihood (MML) estimation, which both assume fixed sample sizes, are commonly used for estimating parameters in the repeated measurements models typically applied to degradation data. However, the LS estimate is not consistent in the case of random sample sizes. This article derives the likelihood for the random sample size model and suggests using maximum likelihood (ML) for parameter estimation. Our simulation studies show that ML estimates have smaller biases and variances compared to the LS and MML estimates. All estimation methods can be greatly improved if the number of specimens increases from 5 to 10. A data set from a semiconductor application is used to illustrate our methods.

Computer Simulation↗
PubMed1997

[A study on fractals in the epidemics of measles].

Fractal is a new field of science to study the complexity and irregularity of events. The basic principles of fractal are introduced in this paper and used in the analyses of measles epidemics in Guangdong Province and Nanping district of Fujian Province, based on the monthly reported data on incidence, from 1951 to 1989. The results show that there are fractals in measles epidemics, the fractal dimensions are 1.588 and 1.626 before vaccination, and change to 1.716 and 1.758 after the vaccination respectively, indicating that the epidemics of mealses have become more complex and irregular than before. It is shown that fractal study is useful in expressing the complexity and irregularity of mealses epidemics.

China↗
PubMed1996

[A case-control study of childhood leukemia].

A 1:1 matched case-control study was conducted to investigate the etiological factors of childhood leukemia. It was found that there were five risk factors: (1) children living in the environmental pollution area, OR (95% CI) = 2.84 (1.14-7.10); (2) exposure to extreme low frequency electronmagnetic field (ELF), OR (95% CI) = 2.01 (1.18-3.42); (3) history of postnatal X-ray exposure, OR (95% CI) = 4.53 (1.68-12.21); (4) history of taking chloramphenicol, OR (95% CI) = 3.60 (1.62-8.01); (5) history of taking, antipyretic or analgesic drugs, OR (95% CI) = 1.93 (1.09-3.42). A protective factor was also discovered. Mothers often eating fish, pork and other meat foods, OR (95% CI) = 0.33 (0.18-0.59). The analysis of the population attributable risk showed that 91% of the childhood leukemia cases might attribute to these five risk factors. The interaction among these etiological factors was estimated. Results showed that there was a positive interaction between the X-ray exposure and chloramphenicol on additive model, the relative excess risk due to interaction (RERI) of childhood leukemia was 3.04.

Adolescent↗
PubMed1994

[Drinking water and leukemia].

A retrospective cohort study was conducted to investigate the relationship between drinking water contamination and risk of leukemia in human being. It was found that the leukemia incidence rate of group D who drank the tap-water from Donghu Lake was significantly higher than that of the groups C and H who drank the tap-water from Changjiang River and Hangjiang River, RR = 1.77, 95% CL = 1.36-2.30, P < 0.01. But the difference between group C and group H is not significant. By using the sex- age-strata analysis; trend and correlation analysis, the results showed that there was a significant positive correlation between the RR of incidence of leukemia and tap-water mutagenicity. It was also connected with pollution of halogenated hydrocarbons in drinking water.

Adolescent↗
PubMed1993

The N-terminal hydrophobic domain of P450c21 is required for membrane insertion and enzyme stability.

Microsomal cytochromes P-450 are known to be integrated into smooth endoplasmic reticulum through their hydrophobic sequences located at the N termini. The length requirement of the membrane insertion signal was determined by the generation of six plasmids encoding mutant P450c21 that lacked various portions of the N-terminal hydrophobic domains. When they were transcribed and translated in vitro in the presence of endoplasmic reticulum membranes, mutant protein lacking more than a third of the first hydrophobic domain gradually lost the ability to insert into the membrane and stayed mostly in the soluble fraction when the first N-terminal hydrophobic domain was removed. The steady-state amount of the truncated proteins was progressively reduced in parallel to the extent of their N-terminal deletions, due to their fast degradation. This process was accompanied by a decrease in the enzymatic activity. Therefore, the first hydrophobic domain of P450c21 not only serves as a membrane targeting and anchoring domain, but it is also important for the in vivo protein stability.

Animals↗
PubMed1993

[Effect of processing on phospholipid of Dioscorea opposita Thunb].

A study of the chemical changes of phospholipid in crude and seven processed samples of Dioscorea opposita was carried out by molybdenum blue colorimetry and TLCS. The result shows that the total phospholipid content in the sample processed by honey bran comes out the highest (180.31 mg/100g).

Chromatography, Thin Layer↗
PubMed1993

[Effect of processing on the extraction of alkaloids from Strychnos].

Results of experiments showed that the contents of strychnine and brucine were about the same in decoction of Strychnos nux-vomica and S. pierriana, but the contents of vomicine, strychnine N-oxide and brucine N-oxide were greater in the former than in the latter. The contents of strychnine and brucine were greater under scalding with hot sand than deep-frying with sesame oil.

Alkaloids↗
PubMed1988

Efficacy of a mass hepatitis B vaccination program in Taiwan. Studies on 3464 infants of hepatitis B surface antigen-carrier mothers.

To evaluate the efficacy of the mass hepatitis B vaccination program in Taiwan in interrupting perinatal hepatitis B virus transmission, 3464 randomly selected 18-month-old infant vaccinees born to hepatitis B surface antigen-carrier mothers were recruited from 9697 eligible infants during a six-month period of the program. They were divided into ten groups according to maternal infectivity and compliance with the vaccination schedule. Serum samples were tested for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. In 786 infants who had highly infectious mothers and who received hepatitis B immune globulin and vaccine on schedule, the protective efficacy was about 85%. The efficacy seemed to be slightly lower in those immunized off schedule. Overall, 11% of infants still carried hepatitis B surface antigen, and 81% of the infants had antibody to hepatitis B surface antigen that exceeded 10 mIU/mL in more than 90% of them. The geometric mean titers of antibody to hepatitis B surface antigen were more than 200 mIU/mL in every group of infants. We conclude that the mass vaccination program is efficacious in preventing perinatal hepatitis B virus transmission and the chronic carrier state; most infant vaccinees have adequate levels of protective antibody at 18 months of age. This program is extremely significant in the control of hepatitis B virus infection in Taiwan.

Carrier State↗
PubMed1986

Characterization of hepatitis B e antigen from human breast milk.

Hepatitis B e antigen (HBeAg) but not surface antigen (HBsAg) was detected in 20% of the milk samples taken from HBsAg carrier mothers by radioimmunoassay. The density of milk e antigen particles was peaked at 1.32 g/ml in CsCl gradient ultracentrifugation. HBeAg was found in 1.33 M and 3.24 M (NH4) 2SO4 precipitates from breast milk but neither of HBeAg in both precipitates showed exactly identical with serum-derived e antigen. Five bands of polypeptides with molecular weight of 8,000, 21,500, 37,000, 53,000 and 68,000 daltons were seen after polyacrylamide gel electrophoresis from the milk e antigen. In addition, the IgA was shown significantly high in HBeAg positive milk.

Centrifugation, Density Gradient↗
PubMedDate not supplied

Paroxysmal nocturnal hemoglobinuria: report of one case.

Paroxysmal nocturnal hemoglobinuria (PNH) is a complex stem cell disorder and its occurrence in childhood is quite uncommon. A 6-year-old girl with pancytopenia was presented. There is no nocturnal hemoglobinuria or other symptoms of chronic hemolysis. Bone marrow examination revealed mild hypocellularity initially, and a tentative diagnosis of aplastic anemia was made. This patient received conventional therapy with uneventful course. Two consecutive episodes of hemolytic transfusion reaction were noted and positive sugar water test and Ham,s test lead the clue of PNH. The literature on the clinical manifestation, pathogenesis, diagnosis and management of PNH is reviewed briefly.

Bone Marrow↗