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Biomedical subjects

L T Lee

Publications and source records attributed to L T Lee.

At least 19 recordsLinked to original sources
PubMed2001

Molecular cloning of a teleost growth hormone receptor and its functional interaction with human growth hormone.

This paper reports the first full-length cDNA sequence of a growth hormone receptor (GHR) from a teleost fish and its functional expression in cultured eukaryotic cells. The cDNA sequence, from Carassius auratus (goldfish), encodes a protein of 602 amino acids (aa) akin in architecture to the GHRs of other species. Despite the presence of motifs characteristic of GHR, the overall homology between the goldfish GHR and other GHRs is very low ( approximately 40% aa identity). CHO cells transfected with this receptor cDNA can be stimulated to proliferate by human growth hormone (hGH). In addition, the transfected cells can transactivate a co-expressed mammalian serine protease inhibitor (Spi) 2.1 promoter upon stimulation by hGH, indicating the successful interaction of the fish receptor with the mammalian ligand to evoke the down-stream post-receptor events. Tissue distribution studies indicated that the receptor is mostly expressed in the liver and hypothalamus of goldfish. A single mRNA transcript of a size of about 4 kb was found in the goldfish liver.

Amino Acid Sequence↗
PubMed2000

Interactions between a lipase and charged surfactants--a comparison between bulk and interfaces.

The interaction between a charged surfactant and a lipase has been investigated by several methods. Interactions in aqueous bulk phase was studied by NMR and by microcalorimetry. Surface tension and neutron reflectivity were used for studies at the air-water interface. Interactions at the interface between a hydrophobic solid surface and water was investigated by ellipsometry. The results obtained are as follows. The cationic surfactant, tetradecyltrimethylammonium bromide (iodide in the NMR experiments), showed strong interaction at the air-water and the hydrophobic solid-water interfaces but no clear indication of an interaction in bulk phase was seen. The anionic surfactant showed no interaction with the lipase neither at the interfaces, nor in bulk. The difference in behavior of the system cationic surfactant-lipase in bulk and at the interfaces may be due to the change in enzyme conformation that is known to occur at interfaces between water and an apolar phase.

Calorimetry↗
PubMed2000

Molecular cloning and expression studies of a prolactin receptor in goldfish (Carassius auratus).

A full-length cDNA clone, of a size of 4.6 kb, for the goldfish prolactin receptor has been isolated. This cDNA clone encodes a protein of 600 amino acids homologous to prolactin receptors of other species. A Kyte-Doolittle hydropathy analysis of the receptor indicates that the translated protein consists of a signal peptide of 22 amino acids, an extracellular domain of 228 amino acids, a single transmembrane domain of 24 amino acids, and an intracellular domain of 346 amino acids. Several characteristic landmarks of prolactin receptor could be identified in this clone. These include the four conserved cysteine residues and the WS motif within the extracellular domain, and the box 1 and box 2 regions of the intracellular domain. Among all the prolactin receptor sequences known to date, this clone bears the closest resemblance to the tilapia prolactin receptor, although homology between these two fish prolactin receptors is rather low. There are only 57.4% of nucleotide and 48.3% of amino acid sequence identities between these two fish receptors. This receptor cDNA was transfected into CHO-K1 cells for functional analysis. RT-PCR analysis with a pair of gene specific primers indicate that the receptor was transcribed in the transfected cells. Using a cell proliferation assay based on the reduction of the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, the receptor transfected CHO-K1 cells can be stimulated to proliferate upon the addition of ovine prolactin in the culture medium. The tissue distribution of the prolactin receptor in goldfish was studied by RT-PCR/Southern analysis and by Northern analysis. The results indicated that the receptor is expressed mostly in the kidney, the gill and the intestine of goldfish, corroborating with the osmoregulatory role of prolactin in fish. In addition, an appreciable level of the receptor is also found in the brain and gonads of goldfish. Northern analysis showed that there are two transcript sizes, a major 4.6 kb and a minor 3.5 kb mRNAs, in the kidney, gill and intestine.

3' Untranslated Regions↗
PubMed1999

Mortality trends of elderly people in Taiwan from 1974 to 1994.

BACKGROUND: the hypothesis that disability and death will eventually be compressed to a period late in life needs empirical confirmation. OBJECTIVES: we have examined the secular trends of life expectancy and common causes of death in the aged population of Taiwan. METHOD: we compared the life expectancy, causes of death and probability of death for people at birth, at age 65 and at age 85 for both sexes from 1974 to 1994 using data from Taiwan government statistics. RESULTS: there has been a substantial gain in life expectancy, especially for men age 85 and over, in the past 20 years. . Mortality due to stroke, ischaemic heart disease, hypertension and chronic pulmonary disease has declined. There has been a steep increase in cancer deaths and deaths associated with diabetes mellitus. Tuberculosis and injury-related deaths have declined but pneumonia deaths have increased. For elderly people, the probability of dying from cancer and ischaemic heart disease increased with time. However, the probability of dying from stroke decreased. Although there was a decrease in probability of deaths associated with falls, there was an increase of deaths due to 'frailty' (as judged by falls, pneumonia and septicaemia). CONCLUSIONS: cancer is a major cause of death in the elderly population of Taiwan. This rapidly expanding elderly population seemed to suffer from poorer health in the later period of their life.

Aged↗
PubMed1999

Differences in diagnostic approach between family physicians and other specialists in patients with unintentional body weight loss.

BACKGROUND: Unintentional weight loss is a diagnostic dilemma with diverse diagnostic possibilities for physicians. OBJECTIVES: Our study focused on the evaluation of differences in diagnostic approach between family physicians and physicians in other specialties. METHODS: Outpatients who visited National Taiwan University Hospital from January 1996 to December 1996 with unintentional weight loss of 5% or more within 6 months were recruited by a computer search. All data were obtained from a structured medical record audit. RESULTS: There was no significant difference in the utilization of common diagnostic laboratory tests between the two groups. However, other specialists ordered more carcinoembryonic antigen tests (P < 0.01) and hepatitis B antigen tests (P < 0.05), but fewer upper gastrointestinal tract barium studies (P < 0.05) than family physicians. For patients without a definite final diagnosis, the diagnostic total costs for laboratory tests and imaging studies were lower for family physicians than other specialists (P < 0.01). For patients with biomedical disorders, the diagnostic cost was not significantly different between the two groups. For patients with psychological disorders, the costs for imaging studies were lower for family physicians than for other specialists (P < 0.05) but there was no significant difference in the total costs between these two groups. CONCLUSIONS: We conclude that the different approaches between the two groups are due to different training backgrounds and characteristics of practice. The patient-centred concepts of family physicians might be more cost-effective in dealing with undifferentiated problems.

Adolescent↗
PubMed1999

Polyelectrolyte brushes: counterion distribution and complexation properties.

The structure of dense grafted polyelectrolyte layers has been studied with a combination of neutron reflectivity and infrared spectroscopy techniques. The polyelectrolyte brushes were made of poly(styrene sulfonate) neutralized by different counterions. Small counterions are distributed throughout the brush in order to ensure a highly local electroneutrality. In addition, they can be readily exchanged with other small ions. On the other hand, macromolecular counterions (as well as some proteins) are irreversibly trapped by the brush, but are located outside the grafted layer and cannot reach the surface.

Journal Article↗
PubMed1999

A study of the noise hazard to employees in local discotheques.

AIM OF STUDY: There is growing concern that amplified music in discotheques can cause hearing loss. This study attempts to evaluate the noise hazard of employees exposed to amplified music in our discotheques. METHOD: Employees comprising of disc jockeys, bartenders, waiters, cashiers and security officers of five selected discotheques were used for the study. Personal noise dosimetry was carried out on 40 employees throughout their workshift. The audiometric examination results of another 46 employees were compared with 37 subjects from a non-exposed match control group. RESULTS: The range of exposure to noise level above 85 dBA for the employees is 3.6 to 6.9 hours with a mean of 5.1 hours. All the occupational groups are exposed to noise level of at least 89 dBA Leq for their whole work shift. The discotheque group has statistically significant higher prevalence (41.9%) of early sensorineural hearing loss compared to the control group (13.5%). A higher proportion of employees in the older age group (above 30 years old) and working longer (above 1 year) suffer from hearing loss. A significant proportion of the discotheque study subjects (21%) also complained of recurrent tinnitus compared to 2.7% in the control group. The younger (< 30 years) and those with shorter exposure duration (< 1 year) appeared to complain of tinnitus more. CONCLUSION: The study shows that all the employees regardless of occupations are exposed to noise above the permissible level of 85 dBA Leq A high proportion of them also suffer from early sensorineural hearing loss and tinnitus.

Adolescent↗
PubMed1998

A case-control study on risk factors for Type 1 diabetes in Taipei City.

To search for non-genetic risk factors for Type 1 diabetes among Chinese, a total of 117 Type 1 diabetes patients identified from the Taipei Type 1 Diabetes Registry and 193 frequency-matched controls with normal glucose tolerance were recruited. The controls were selected from classmates or colleagues of cases with similar distributions of age, sex, and parental and individual educational levels. Information on Type 1 diabetes risk factors was obtained through standardized interviews according to a structured questionnaire administered by two trained nurses. In the univariate analyses, the order of pregnancy of the study subject, the number of spontaneous and induced abortions reported by the mother before giving birth to the study subjects, the duration of breast-feeding and monthly family income were significantly associated with Type 1 diabetes in a dose-response manner. There was a U-shaped relationship with Type 1 diabetes for birth weight and paternal age at the conception of the study subjects. After further adjustment for multiple risk factors through logistic regression analysis, the biological gradient for pregnancy order, duration of breast-feeding, and the U-shaped relationship for paternal age remained statistically significant.

Abortion, Induced↗
PubMed1996

Identification of cryptic peanut agglutinin-reactive sites in human lipoprotein(a).

After treatment of human lipoprotein(a) (Lp(a)) with neuraminidase, formerly cryptic sites became available for binding to peanut agglutinin (PNA) lectin and a Thomsen-Friedenreich antigen (T-antigen)-specific monoclonal antibody. The PNA-reactive sites were localized to the apo(a) moiety of Lp(a) and O-specific carbohydrate side chains. Lp(a) with larger isoforms of apo(a) contained more potential PNA reactivity per molecule of Lp(a) apoB than did smaller isoforms. Very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL) did not contain comparable amounts of the cryptic PNA-reactive sites.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1995

[Community-based hepatocellular carcinoma screening in seven townships in Taiwan].

The early detection and prompt treatment of hepatocellular carcinoma (HCC) may prolong life and improve the quality of life of affected patients. In order to compare sensitivity and specificity of various screening biomarkers, identify subjects with a high risk of developing HCC, and estimate prevalence and incidence of HCC among subjects, a community-based HCC screening program was implemented in Sanchi, Chutung, Potzu, and Kaohsu, Taiwan Island as well as Makung, Huhsi and Paihsa in Penghu Islets. First stage screening of HCC was based on serological markers including hepatitis B surface antigen (HBsAg), antibody against hepatitis C virus (anti-HCV), alpha-fetoprotein (AFP > or = 20 ng/mL), alanine transaminase (> or = 40 IU/L), and aspartate transaminase (> or = 45 IU/L); as well as history of liver cirrhosis or HCC among first-degree relatives. Subjects who were positive for at least one of above six first-stage criteria were referred for second-stage screening by abdominal ultrasonography. Confirmatory diagnosis of HCC was made in suspicious cases according to aspiration cytology surgical pathology, digital substracted angiogram and/or computed tomography. A total of 12,026 men in seven study townships and 1,800 women in two townships in Penghu were recruited for first-stage screening (response rate: men, 25.5%; women, 46.8%). The positive rates for first-stage screening were 30.9% men and 34.6% women. The response rates for second-stage screening were 91% men and 90.5% women. Age-standardized prevalence of HCC per 1,000 subjects was 5.2 for men and 0.8 for women in Penghu Islets and 1.2 for men on Taiwan island. Among five serological biomarkers, HBsAg carrier status had the highest sensitivity (88.2%) and AFP had the second highest sensitivity (43.1%). The specificity of these markers was highest for AFP (99.0%) and lowest for HBsAg carrier status (80.3%). There were 16 new HCC cases identified after an intensive follow-up of 137 cases affected with liver cirrhos is giving an annual HCC incidence rate of 5.3%, while the rate for non-cirrhotic subjects who were positive on first-stage screening was only 0.15%. The combination of HBsAg and AFP for the first-stage screening and abdominal ultrasonography for the second-state screening seems valid for the early detection of HCC, but its cost-effectiveness remains to be elucidated by a longer follow-up study.

Adult↗
PubMed1994

Age-period-cohort analysis of pulmonary tuberculosis mortality in Taiwan: 1961 to 1990.

The specific aim of this study was to examine the effects of age, calendar period of death, and birth cohort in pulmonary tuberculosis (TB) mortality in Taiwan during the period 1961 to 1990. A log-linear Poisson regression model modified from the method of Osmond and Gardner was used and 79,881 deaths (58,025 males and 21,856 females) were included in the analysis. Birth cohort is the most significant predictor of pulmonary TB mortality according to the model. The earliest birth cohort from 1891 had a pulmonary TB mortality 17,327 and 6,186 times those born from 1986 for males and females, respectively. There was also a significant age effect. The youngest age group of zero to four years had a pulmonary TB mortality 7.10 and 5.87 times those for the age group of five to nine years for males and females, respectively. The oldest age group of 70 to 74 years had a risk of pulmonary TB mortality 2.89 and 1.88 times those for the five- to nine-year age groups for males and females, respectively. Parameters of the period factor showed a decreasing pulmonary TB mortality from 1961 to 1990 that was less significant than those of age or cohort. In addition to the improvement in medical measures that influenced the effect of calendar year on TB mortality, year of birth is an important determinant in the trend of TB mortality in Taiwan. The result shows that the major focus for TB mortality in Taiwan is in the age groups born between 1891 and 1921.

Adolescent↗
PubMed1994

[Family influence on cancer screening participation in seven communities in Taiwan].

Cancer is the leading cause of death in Taiwan. Since there is no definitive method for cancer prevention, early detection play a major role in fighting cancer. Factors that affect people's willingness to participate cancer screening have been discussed widely except for those relating to the family. The family's role in motivation & influencing its members to participate in an invited cancer-screening program was studied in seven Taiwanese communities. 5% of participants in each area for both genders were chosen by stratified random sampling, and matched with teice-informed nonparticipants who were chosen by sex, age, and neighborhood. By means of a home visit and structured questionnaire, 729 of the 987 eligible cases were interviewed (73.9%). The main findings were that the response was higher among people with higher education, nonsmokers, and those who felt the scheduled time and place of attendance was suitable and convenient. Moreover, in the 6 variables related to family (family structure, family life cycle, cancer history in family and friends, family APGAR, family support about health problems, and family's opinion about cancer screening), the last 4 variables were found to be significantly related by chi-square analysis to the attendance. Finally, a logistic regression analysis adjusted by age, sex, education, smoking habits, time available and traffic factors was used to analyze how family factors affect attendance. The result was cancer history in family and friends (odd ratio = 2.42) and family's encouragement (odd ratio = 1.85) had a positive association.

Adult↗
PubMed1993

Analysis of apolipoprotein size distribution by electroimmunoblotting from non-denaturing composite gels.

An exponential gradient gel with 0-35% acrylamide and 0.5% agarose was developed for electrophoresis of intact lipoproteins with subsequent electroimmunoblotting. The system resolved in a single gel lipoprotein-associated proteins of sizes from 'free' apoproteins to VLDL. Reproducibility between gels was good (coefficient of variation < 8%). Examination of the effect of mild glutaraldehyde fixation on immunodetection showed variable results (lack of effect on apos (a), AII, and AIV; inhibition of apoB; enhancement of apos AI and E). The composite gel system described here will simplify analysis of apolipoprotein distributions in both health and disease and therefore will likely be useful in future clinical applications.

Apolipoproteins↗
PubMed1993

Family factors affecting the outcome of tuberculosis treatment in Taiwan.

Despite the progress of tuberculosis (TB) control, the failure of treatment mainly due to non-adherence to medical recommendations remains a major obstacle to the eradication of this disease in both industrialized and developing countries. We interviewed 397 active pulmonary TB cases (274 males and 123 females) in Taiwan and followed up their treatment outcomes. No significant differences were found between any of the groups of either sex on TB cognition scores. Positive correlations between cognition scores and compliance scores, between cognition scores and family apgar scores, and between compliance scores and family apgar scores were noted in this study. In males, the complete treatment group had a higher compliance score (mean +/- standard deviation = 13.45 +/- 2.80) and family apgar score (22.44 +/- 2.29) than the incomplete treatment group (11.61 +/- 3.21 and 14.77 +/- 3.92, respectively). In females, the complete treatment group had a higher cognition score (65.99 +/- 6.75), compliance score (13.65 +/- 2.55) and family Apgar score (22.78 +/- 2.30) than the incomplete treatment group (62.05 +/- 6.91, 11.70 +/- 3.04 and 14.84 +/- 3.80, respectively). In the logistic regression analysis, both the family Apgar score and compliance score were significantly related to the TB treatment outcomes. The subjects with a family Apgar score higher than 20 had a chance to complete treatment as high as 72-fold (95% confidence interval = 31.7-164.0) that of those with a score less than 20.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Morbidity and mortality trends of pulmonary tuberculosis in Taiwan.

An epidemiologic study of pulmonary tuberculosis was carried out to examine the secular trend and geographic variations of the incidence, prevalence and mortality of pulmonary tuberculosis in Taiwan. The prevalence and incidence rates declined-steadily from 1910 to 1980, but have remained unchanged during the last decade. Mortality also showed an 8.0% annual decrease from 1974 to 1986, but has remained constant without any apparent changes in recent years. Mortality for pulmonary tuberculosis is much higher in the aboriginal areas, where patients have a poor adherence to treatment and where a high prevalence of alcohol abuse exists. The mortality for pulmonary tuberculosis in Taiwan is higher than that in most developed countries, such as the U.K. and the U.S.A., but is lower than that in mainland China and the Republic of Korea.

Adolescent↗
PubMed1990

Cerebellar units show several types of early responses to telencephalic stimulation in catfish.

The responses of cerebellar units following electrical stimulation applied to the area dorsalis centralis (Dc) of the telencephalon were studied in the siluroid teleost Ictalurus nebulosus. Two kinds of units are distinguished on physiological criteria, identified as Purkinje and eurydendroid cells (the efferent neurons of the cerebellum in teleosts equivalent to cells of the deep nuclei in other vertebrates). A high proportion of both kinds of units in the corpus cerebelli are sensitive to such stimulation. Each kind of unit shows several consistent response types. Purkinje cells fire simple spikes spontaneously at the rate of 8-50 spikes/s and respond to a single shock to Dc with an initial latency of 34-64 ms. The response can be one of the following types: (1) inhibition alone, with a duration of 0.3-1.5 s; (2) initial inhibition for 0.04-0.2 s, followed by postinhibitory rebound, or (3) initial excitation followed by inhibition which may or may not be followed by a late excitation. It is suggested that the initial excitation and the initial inhibition reflect the activation of mossy fiber-granule cell-Purkinje cell circuitry and mossy fiber-granule cell-inhibitory interneuron-Purkinje cell circuitry, respectively. Indirect evidence suggests the involvement of climbing fibers, but their characteristic complex spikes are rarely seen. Changing the stimulation sites within Dc does not appear to change the response pattern but may alter the threshold intensities, latencies and amplitudes. Changing stimulation frequency has complex effects depending on the response type. Purkinje cells responding with initial excitation are located along the lateral edges and along the midline of the corpus cerebelli; units responding with initial inhibition are more often found in an intermediate zone. This suggests three sagittal bands on each side. The contralateral cerebellum has a relative excess of Purkinje cells with initially inhibitory response. Putative eurydendroid cells show either initial excitation or a pattern of inhibition, excitation, inhibition. The initial latency is longer than in Purkinje cells. The contralateral cerebellum has a relative excess of eurydendroid cells with initially excitatory response. The high proportion of units that respond to Dc stimulation, their complex dynamics, diverse response types and compartmentalization point to the importance of the cerebrocerebellar influence in teleosts. Principal differences from mammals are the much longer latencies and less differentiation according to place of stimulation in the cerebrum.

Animals↗
PubMed1990

Cerebellar units show several types of long-lasting posttetanic responses to telencephalic stimulation in catfish.

Extracellular spikes from Purkinje and eurydendroid cells as well as evoked field potentials were recorded from the cerebellum in a catfish following trains of 50-100 stimuli at 2-10 Hz delivered to the area dorsalis centralis (Dc) of the telencephalon. Forty out of 48 Purkinje cells tested showed some response, either an increase or a decrease in the level of ongoing spike discharge following the 10- to 25-second tetanic pulse trains. The altered level lasted for greater than 3 min. Four out of 16 eurydendroid cells showed an increase in posttrain ongoing discharge; none showed a decrease. In those Purkinje cells responding to single pulse stimulation with early excitation, that response was converted to early inhibition during the later cycles of a tetanic pulse train. When tested with posttrain stimulation, they resumed the pretrain early excitation about 100 s after the train; before that, the recovery stages are complex, neither a simple continuation of, nor a simple rebound from, the later cycles of the stimulus train. Bursting discharge of Purkinje cells is often induced or, if already present, enhanced and regularized, typically at approximately 3/s, by train stimulation of Dc. This pattern begins during the train but continues for tens of seconds after its end. The effects of a stimulus train on the mean frequency and on the pattern of ongoing discharge depend on the train parameters: intensity, duration and stimulus rate within the train; 4-5 Hz is most effective. Higher rates or repeated trains produce a more intense but shorter-lasting effect. Evoked field potentials change during a train, and posttrain test stimuli show a slow recovery, especially after longer pulse trains. The cerebrocerebellar influence in a teleost is nontrivial, widespread, differentiated and shows long-lasting posttetanic plasticity.

Animals↗