Biomedical subjects

S C Lin

Publications and source records attributed to S C Lin.

At least 127 records · Page 7Linked to original sources

PubMed1995

The Ames dwarf gene is required for Pit-1 gene activation.

The tissue-specific POU domain transcription factor Pit-1 is required for phenotypic specification of three cell types in the anterior pituitary gland of mammals: somatotropes, thyrotropes, and lactotropes. Mutations in the Pit-1 gene, as first described in Snell and Jackson dwarf (dw) mice, led to pituitary hypoplasia due to lack of these three cell types, as well as hypothyroidism and dwarfism because of deficiency of thyroid-stimulating hormone and growth hormone, respectively. The Ames dwarf (df) exhibits a phenotype identical to that of Pit-1 mutated mice but the defective gene has been mapped to a locus on mouse chromosome 11, distinct from the Pit-1 gene located on mouse chromosome 6. Our studies indicate that initial activation of the Pit-1 gene is deficient in the Ames dwarf. This suggests that the df gene is required for activation of the Pit-1 gene and provides evidence for a hierarchy of tissue-specific factors required for cellular commitment in the anterior pituitary gland.

Animals↗

PubMed1995

Pulmonary metastasis of hepatocellular carcinoma associated with transarterial chemoembolization.

UNLABELLED: Recent advances in both diagnosis and treatment of hepatocellular carcinoma have improved the prognosis and changed the clinical significance of the subsequently increasing distant metastases. Pulmonary metastasis of hepatocellular carcinoma associated with transcatheter arterial chemoembolization has rarely been reported. METHODS: To evaluate whether transcatheter arterial chemoembolization increases the risk of pulmonary metastasis of hepatocellular carcinoma, 230 patients were studied. Among them, 156 received transcatheter arterial chemoembolization with an interval of 12-16 weeks, the remaining 74 cases refused transcatheter arterial chemoembolization and received only conservative treatment. All patients were followed up with chest x-ray films taken before transcatheter arterial chemoembolization, during admission or in the out-patient department. The mean follow-up interval was 3.37 +/- 1.51 months. RESULTS: Pulmonary metastasis was found in 25.6% (40/156) and 8.1% (6/74) of the patients with and without transcatheter arterial chemoembolization (p = 0.002). The median interval between initial diagnosis and pulmonary metastasis was 3.39 +/- 0.08 and 11.72 +/- 2.91 months among patients with and without transcatheter arterial chemoembolization (p = 0.001). The mean age, sex, existence of cirrhosis, severity of cirrhosis, presence of collateral arterial circulation, amount of lipiodol and agent of anti-cancer drugs were not associated with the development of lung metastasis. However, factors predisposing to lung metastasis included: solitary tumor with tumor size > 10 cm, multiple tumors with main tumor > 5 cm or diffuse hepatocellular carcinoma, intrahepatic portal vein thrombosis, arterioportal or arteriovenous shunt, and the presence of incomplete tumor necrosis after transcatheter arterial chemoembolization (especially combined with necrotic area > 50% main tumor size). CONCLUSIONS: Pulmonary metastasis associated with transcatheter arterial chemoembolization has a strong adverse impact on patient survival.

Analysis of Variance↗

PubMed1995

Protective and therapeutic effects of Curcuma xanthorrhiza on hepatotoxin-induced liver damage.

Curcuma xanthorrhiza Roxb. (Zingiberaceae family, commonly known as temu lawak or Javanese turmeric in Indonesia), which is found both wild and cultivated in Indonesia, has been traditionally used for medicinal purposes. C. xanthorrhiza is also used as a tonic in Indonesia. The aim of the present study is to clarify whether C. xanthorrhiza treatment may prevent acute liver damage induced by acetaminophen and carbon tetrachloride in mice. The results clearly indicated that extract of C. xanthorrhiza could reduce significantly the acute elevation of serum transaminases levels induced by the two kinds of hepatotoxins, and alleviated the degree of liver damage at 24 hours after the intraperitoneal administration of two hepatotoxins. It may be concluded that C. xanthorrhiza can protect the liver from various hepatotoxins, hence C. xanthorrhiza could be useful in the treatment of liver injuries and has promise as a kind of broad spectrum hepatoprotective agent.

Acetaminophen↗

PubMed1995

Detection of cardiovascular shunts by transesophageal echocardiography in patients with pulmonary hypertension of unexplained cause.

The purpose of this study was to validate the usefulness of transesophageal echocardiography (TEE) in the assessment of cardiovascular shunts in patients with pulmonary hypertension (PH) of unexplained cause. Twenty-four adult patients, 16 women, 8 men; 15 to 70 years of age, with PH of unexplained cause were studied. All were examined by transthoracic echocardiography (TTE) and TEE. TTE showed the ventricular septal defect in two patients, muscular type in one and perimembranous type in the other. TEE showed the atrial septal defect in eight patients (secundum type in six and primum type in the remaining) and the patient ductus arteriosus in six patients, which were not seen by TTE. The ventricular septal defect shown by TTE was also found by TEE. Patients with a ventricular septal defect were also associated with a patient ductus arteriosus. Among 14 patients with cardiovascular lesions, nine patients displayed a pattern of bidirectional shunt, four a pure left-to-right shunt, and the remaining one a pure right-to-left shunt. All of the cardiovascular defects could be confirmed by passage of the catheter across the defect at cardiac catheterization. In light of PH, transthoracic identification of cardiovascular shunts is difficult because of the low velocity across the defect. In this study, we found that TEE was superior to TTE in detecting and localizing cardiovascular malformations in patient with PH.

Adolescent↗

PubMed1995

Diagnostic accuracy of transesophageal echocardiography for detecting patent ductus arteriosus in adolescents and adults.

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of patent ductus arteriosus (PDA) in the adolescent and the adult, 40 patients with PDA and 50 patients with other congenital heart diseases were studied. All echocardiograms were recorded before cardiac catheterization and surgery. The echocardiographic diagnosis of PDA was made by direct visualization of a shunt flow in the duct. A mosaic flow in the pulmonary artery without direct visualization of the duct was considered possible but not definitely diagnostic of PDA. TEE showed greater sensitivity and negative predictive value than TTE (97% vs 42%, and 98% vs 68%, respectively; p < 0.001) in confirming the diagnosis of PDA. The specificity and positive predictive value in establishing the diagnosis of PDA were the same for both techniques. In the subgroup of patients with Eisenmenger's syndrome, the sensitivity of TEE and TTE in confirming diagnosis of PDA was 100% and 12% (p < 0.01), respectively. The sensitivity of monoplane and biplane TEE in the diagnosis of PDA was comparable (95% and 100%, respectively; p = NS). In conclusion, TEE was highly sensitive and specific in detecting PDA in adolescents and adults. It was also highly valuable for detecting the cause of pulmonary hypertension in patients with Eisenmenger's syndrome.

Adolescent↗

PubMed1995

Hepatic actinomycosis: a case report.

A 64-year-old man with hepatic actinomycosis presented with several months of weight loss and poor appetite. However, no fever was noted before admission. Findings on abdominal sonography and computed tomography scan were suggestive of hepatocellular carcinoma. A sono-guided percutaneous liver biopsy specimen demonstrated only chronic fibrosing inflammation. Therefore, laparotomy was performed and the diagnosis of hepatic actinomycosis was established after surgical resection. The patient was then successfully treated. The fact that hepatic actinomycosis may be very similar to hepatocellular carcinoma should be highly suspected. The hospital course of this patient concerning this condition and a brief review of the literature are presented to illustrate the diagnostic difficulties which may be encountered in such cases.

Actinomycosis↗

PubMed1995

Prevalence of antibodies to hepatitis C virus in patients with nonalcoholic fatty liver.

BACKGROUND: Nonalcoholic fatty liver can be caused by obesity, diabetes mellitus, hyperlipidemia or nonalcoholic steatohepatitis. Hepatitis C viral infection can also cause macrovesicular steatosis and such inflammation of the liver as nonalcoholic steatohepatitis. To determine whether the prevalence of anti-HCV is higher in patients with nonalcoholic fatty liver, this clinical study was undertaken; we also tried to detect which factors predict the presence of anti-HCV in these patients. METHODS: The study included 205 nonalcoholic fatty liver patients (122 males and 83 females) with a mean age of 46.5 years, diagnosed by ultrasonic examination, on whom anti-HCV antibody tests were then done. RESULTS: Eleven cases (5.4%) were anti-HCV positive with a higher mean age of 56.4 +/- 11.1 years (p < 0.05). Anti-HCV positive patients had higher serum AST and ALT levels than negative patients (95 +/- 59 U/L, 166 +/- 116 U/L vs. 34 +/- 26 U/L, 51 +/- 43 U/L; p < 0.05), while anti-HCV negative patients had higher mean body weight (124 +/- 15% vs. 114 +/- 11% of IBW) and serum cholesterol levels (202 +/- 41 mg/dl vs. 159 +/- 45 mg/dl). There was no statistical difference between anti-HCV positive and negative groups in clinical parameters including gender, presence of HBsAg, history of DM, operation, blood transfusion, oral contraceptive usage, and cancer with or without chemotherapy. The prevalence of anti-HCV increased with age from 1.8% in the fourth and fifth decades to 25% in the eighth decade. The prevalence of anti-HCV was 1.4% (1 case) in 72 fatty liver with normal biochemical tests and 7.5% (10 cases) in 133 cases with abnormal biochemical tests, a difference which was statistically marginally significant (p = 0.055). Those with ALT levels greater than three-fold the normal limit had a significantly higher anti-HCV prevalence rate (25.9%) than those with normal (1.4%) or mildly (2.8%) elevated ALT levels (p < 0.001). Logistic regression analysis revealed that only age and serum ALT levels were independent predictive factors for the presence of HCV infection. CONCLUSIONS: Results revealed that the prevalence of anti-HCV in patients with nonalcoholic fatty liver was 5.4%, slightly higher than in the general population. Age and serum ALT level were the predictive factors for the presence of HCV infection.

Adult↗

PubMed1994

Nasal septum lesions caused by chromium exposure among chromium electroplating workers.

A chromium electroplating worker, suffering from epistaxis during work, was found to have nasal septum perforation. To determine the etiology and prevalence of nasal septum lesions, we conducted a survey of seven chromium electroplating factories and examined 79 workers. Forty workers from three aluminum electroplating factories were also enrolled as the reference group. Subjects were thoroughly examined by an otolaryngologist and each of them provided a blood and urine sample. A questionnaire interview regarding symptoms of the upper respiratory tract, past medical history, life style, and work history was also conducted. Air chromium concentrations were measured by taking area samples for 4-6 hours. Based on field observation and chromium measurements, we divided chromium electroplating into three different exposure zones: workers directly dealing with electroplating tanks (n = 31), other process workers (n = 29), and office workers and drivers (n = 19). Among the 79 chromium electroplating workers, there were 16 cases of nasal septum perforation, and 42 with either scar formation or ulceration; 10 chromium electroplating workers developed skin ulcers after performing chrome plating. No workers from aluminum electroplating factories had any nasal septum or skin abnormalities. There was a consistent trend between the degree of chromium exposure and the signs and symptoms related to the nose, throat, and skin. Immediate improvement of occupational hygiene is warranted.

Adult↗

PubMed1994

Effects of thymosin beta 4 and thymosin beta 10 on actin structures in living cells.

The beta-thymosins are a family of small proteins originally isolated from the thymus. Recently, two of the major mammalian isoforms, thymosin beta 4 (T beta 4) and thymosin beta 10 (T beta 10), are identified as significant actin monomer sequestering proteins which may be involved in regulating actin filament assembly. To study the cellular function of beta-thymosins, we have used isoform-specific antibodies to determine their concentration and intracellular distribution, and examined the effects of inducing overexpression of T beta 4 and T beta 10 on actin filament structures. Immunofluorescence labeling of peritoneal macrophages showed that both beta-thymosins are uniformly distributed within the cytoplasm. cDNA-mediated overexpression of beta-thymosins in CV1 fibroblasts induced extensive loss of phalloidin-stained actin stress fibers. Stress fibers in the cell center were more susceptible than those at the periphery. There was a decrease in the number of focal adhesions, as evidenced by a decrease in discrete vinculin staining and an increase in diffuse vinculin fluorescence. The majority of the transfected cells had normal shape in spite of extensive loss of actin filaments. Occasionally, cells overexpressing beta-thymosin were observed to divide. In these cells, beta-thymosin was excluded from the midbody which contains an actin filament-rich contractile ring. Our results indicate that T beta 4 and T beta 10 are functionally very similar and both are effective regulators of a large subset of actin filaments in living cells.

Actin Cytoskeleton↗

PubMed1994

Disruption of T lymphocyte reappearance in anti-Thy-1-treated animals in vivo with soluble CD44 and L-selectin molecules.

We used polyclonal rabbit anti-Thy-1 antiserum to eliminate T lymphocytes in the peripheral blood, lymph nodes, and spleens but not in the thymus of normal mice. T lymphocytes began to reappear in the peripheral lymphoid compartments 2 weeks after termination of the treatment. By 4 weeks, the numbers of peripheral T lymphocytes had recovered to normal levels. We found that injection of recombinant soluble forms of human CD44 or L-selectin but not human CD8 molecules delayed the reappearance of peripheral T lymphocytes in anti-Thy-1-treated mice. This delay in recovery most likely reflects the ability of these soluble receptors to interfere with lymphocyte migration in vivo. Our results provide in vivo evidence that CD44 and L-selectin regulates lymphocyte trafficking and suggest that soluble forms of both molecules provide useful tools for the study of lymphocyte migration in vivo.

Animals↗

PubMed1994

Occurrence of plasmids and tetracycline resistance among Campylobacter jejuni and Campylobacter coli isolated from whole market chickens and clinical samples.

Twenty whole market chickens, purchased from 10 different stores in the Taipei Metropolitan area, were examined for the presence of Campylobacter jejuni and Campylobacter coli. The microorganisms were recovered from 95% of the chickens. A survey of different sites on--breast, thigh and tail--showed that contamination was equally common on all these sites. One hundred and sixty-seven chicken isolates and the 41 clinical isolates of Campylobacter jejuni were examined for the occurrence of plasmid DNA in association with tetracycline resistance. A high plasmid occurrence rate of 91% and 44% was observed for C. jejuni from chickens and clinical isolates, respectively. Plasmids ranged in size from 16 to 208 Kb. A 61 Kb plasmid and a 50 Kb plasmid were common to the chicken isolates and clinical isolates, respectively. All chicken isolates and 78% of clinical isolates were tetracycline-resistant. The high rate of tetracycline resistance in chicken isolates probably related to use of tetracycline as a growth promoter for poultry. A tetO DNA Probe, highly specific for the detection of tetracycline resistance in C. jejuni and C. coli, was used to find the location of tetracycline resistance. Of 157 chicken isolates, 98% of isolates were positive with the tetO probe, 87% (137/157) on plasmids and 11% (17/157) on the chromosome; only three isolates did not hybridize with the tetO probe. Of 32 clinical isolates, 88% isolates hybridized with the tetO probe, 47% (15/32) on plasmids and 41% (13/32) on the chromosome; four isolates did not hybridize with the tetO probe.

Animals↗

PubMed1994

Palmitoylation of CD44 interferes with CD3-mediated signaling in human T lymphocytes.

We studied the interactions between CD44 and four different monoclonal anti-CD44 antibodies. All four monoclonal anti-CD44 antibodies studied (P3H9, Bu52, IM.7, and GKW.A3) act in synergy with human anti-CD2 antibodies in stimulating normal human peripheral blood lymphocytes to proliferate. GKW.A3 and IM.7 but not P3H9 or Bu52 inhibited the proliferation of normal human peripheral blood lymphocytes stimulated by anti-CD3. Interestingly, only GKW.A3 and IM.7 stimulated the incorporation of [3H]palmitic acid and palmitoylation of CD44 molecules by normal human peripheral blood lymphocytes. The two monoclonal anti-CD44 antibodies (P3H9 and Bu52) that failed to inhibit anti-CD3 induced proliferation also failed to induce the incorporation of [3H]palmitic acid. More importantly, the inhibitory effects of GKW.A3 were reversed in the presence of cerulenin, an inhibitor of protein palmitoylation. Therefore, palmitoylation of CD44 may interfere with anti-CD3 mediated signaling pathways. These data support the hypothesis that palmitoylation of cell surface receptors may play an active role in receptor and receptor interactions and signal transduction in normal human T lymphocytes.

Antibodies, Monoclonal↗

PubMed1994

Structural and immunological characterization of a biosurfactant produced by Bacillus licheniformis JF-2.

Bacillus licheniformis JF-2 produces a very active biosurfactant under both aerobic and anaerobic conditions. We purified the surface-active compound to homogeneity by reverse-phase C18 high-performance liquid chromatography and showed that it is a lipopeptide with a molecular weight of 1,035. Amino acid analysis, fast atom mass and infrared spectroscopy, and, finally, 1H, 13C, and two-dimensional nuclear magnetic resonance demonstrated that the biosurfactant consists of a heterogeneous C15 fatty acid tail linked to a peptide moiety very similar to that of surfactin, a lipopeptide produced by Bacillus subtilis. Polyclonal antibodies were raised against surfactin and shown to exhibit identical reactivity towards purified JF-2 lipopeptide in competition enzyme-linked immunosorbent assays, thus providing further evidence for the structural similarity of these two compounds. Under optimal conditions, the B. licheniformis JF-2 biosurfactant exhibits a critical micelle concentration of 10 mg/liter and reduces the interfacial tension against decane to 6 x 10(-3) dyne/cm, which is one of the lowest interfacial tensions ever reported for a microbial surfactant.

Amino Acid Sequence↗

PubMed1994

Protective and therapeutic effects of ban-zhi-lian on hepatotoxin-induced liver injuries.

The hepatoprotective effect of Ban-zhi-lian was investigated in three kinds of experimental models. The animals were treated with Ban-zhi-lian (300 mg/kg, p.o.) at 2,4, and 10 hours after carbon tetrachloride (32 l/kg, i.p.), acetaminophen (600 mg/kg, i.p.), and beta-D-galactosamine (188 mg/kg, i.p.) administration. Significant protective effects from these hepatotoxins were expressed. This protection was evidenced by comparing the serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), and histopathologic examination in animals treated and untreated with Ban-zhi-lian. Serum enzyme activities were significantly lower in Ban-zhi-lian-treated groups. In the histopathologic observation, liver damage induced by three hepatotoxins was markedly improved in Ban-zhi-lian treated animals. These results demonstrated that Ban-zhi-lian has a protective effect against experimental liver damage induced by various hepatotoxins.

Acetaminophen↗

PubMed1994

Hepatoprotective effects of Taiwan folk medicine: wedelia chinensis on three hepatotoxin-induced hepatotoxicity.

The hepatoprotective effects of a Taiwanese crude herb, Hwang-hua-mih-tsay (Wedelia chinensis (Osbeck) Merr.), were investigated. Acute hepatitis was induced by three hepatotoxins: carbon tetrachloride and acetaminophen in mice, and D(+)-galactosamine in rats. After treatment with W. chinensis (300 mg/kg, p.o.) at 2, 6 and 10 hours, a reduction in the elevation of serum glutamate oxaloacetic transaminase (SGOT) and glutamate pyruvic transaminase (SGPT) levels was observed at 24 hrs after hepatotoxins were administered. These serological observations were confirmed by histopathological examinations. A microscopic examination of the liver showed a marked improvement in groups receiving W. chinensis. In order to further confirm the hepatoprotective effect of W. chinensis, all pharmacological and histopathological effects were compared with Bupleurum chinense DC. (family Umbelliferae), a well documented antihepatotoxicity herb. It was concluded that W. chinensis has a definite hepatoprotective effect against liver injuries.

Acetaminophen↗

PubMed1994

Hepatoprotective effects of Taiwan folk medicine: Ixeris chinensis (Thunb.) Nak. on experimental liver injuries.

The hepatoprotective effects of Ixeris chinensis (Thunb.) Nak. were studied on acute hepatitis induced in mice by a single dose of carbon tetrachloride (31.25 microliters/kg, ip) or acetaminophen (600 mg/kg, ip), and in rats by a single dose of beta-D-galactosamine (188 mg/kg, ip). Hepatoprotective activity was monitored by estimating the serum transaminases (SGOT and SGPT) levels and histopathological changes in the livers of experimental animals. The Ixeris chinensis (Thunb.) Nak. extracts significantly inhibited the acute elevation of serum transaminases. Histopathologically, the crude I. chinensis extract significantly ameliorated hepatotoxin-induced histopathological changes in the livers of experimental animals. All pharmacological and histopathological effects of Ixeris chinensis (Thunb.) Nak. were compared with Bupleurum chinense DC., which has been previously reported as a treatment herb for hepatitis.

Alanine Transaminase↗

PubMed1994

Inhibition of presynaptic catecholamine synthesis with alpha-methyl-para-tyrosine attenuates nocturnal melatonin secretion in humans.

The catecholamine dopamine (D) is involved in the regulation of LH and PRL secretion, whereas a dysregulated noradrenergic system may contribute significantly to symptoms encountered in affective disorders. This explains the attraction of using alpha-methyl-para-tyrosine (AMPT) in neuroendocrine and psychiatric research, as it inhibits both neurotransmitters. PRL has been used as a marker of the effectiveness of AMPT in blocking D function, but no good marker for the effectiveness of AMPT in blocking norepinephrine (NE) is available. The purpose of this study was to determine whether melatonin (M) might serve as such a marker, as its production and secretion are regulated by NE. Seven subjects were given either AMPT or promethazine, which does not alter M secretion, in a randomized, double blind fashion, and 24-h M secretion was studied. Two-way analysis of variance revealed a significant difference in M secretion (F = 13.2; df = 17,102; P = 0.0013), with the following time points being different: 22, 23, 24, 1, 2, 3, 4, 5, and 6 h. Also, 24-h urinary 6-sulfatoxymelatonin excretion correlated highly with 24-h M secretion, expressed as the area under the curve in the AMPT experiment (r = 0.93; P = 0.002), which indicates that AMPT does not alter the metabolism of M. These results demonstrate for the first time that AMPT significantly attenuates nocturnal M secretion. It is concluded that M is a good marker for characterizing the effectiveness of AMPT in inhibiting sympathetic NE activity.

Adult↗

PubMed1994

Pituitary ontogeny of the Snell dwarf mouse reveals Pit-1-independent and Pit-1-dependent origins of the thyrotrope.

The anterior pituitary provides a model to study the molecular mechanisms responsible for emergence of distinct cell types within an organ. Dwarf mice (Snell) that express a mutant form of the tissue-specific POU-domain transcription factor Pit-1 fail to generate three cell types, including the thyrotrope (S. Li, E. B. Crenshaw, E. J. Rawson, D. S. Simmons, L. Swanson and M. G. Rosenfeld (1990), Nature 347, 528-533). Analyses of wild-type and Pit-1-defective mice, presented here, have revealed that thyrotropes unexpectedly arise from two independent cell populations. The first population is Pit-1-independent and appears on e12 in the rostral tip of the developing gland, but phenotypically disappears by the day of birth. The second is Pit-1-dependent and arises subsequently in the caudomedial portion of the developing gland (e15.5), following the initial expression of Pit-1 in this region. The failure of caudomedial thyrotrope cells to appear in the Snell dwarf, and the observation that Pit-1 can bind to and transactivate the TSH beta promoter, apparently enhanced by its phosphorylation, suggests that Pit-1 is directly required for the appearance of this distinct population that serves as the precursors of the mature thyrotrope cell type. These data suggest that different molecular mechanisms, based on the actions of distinct transcription factors, can serve to independently generate a specific cell phenotype during mammalian organogenesis.

Animals↗