Biomedical subjects

K C Lin

Publications and source records attributed to K C Lin.

At least 37 records · Page 2Linked to original sources

PubMed2000

Phospholipase A(2) activity, heat shock protein, and superoxide dismutase in rat remnant kidney.

Male Sprague-Dawley rats (150-200 g) were randomly assigned to sham operation (n=6) or 5/6 nephrectomy (n=12) procedures. Two weeks after the completion of the 5/6 nephrectomy, these animals were again randomly assigned to two groups: non-treatment or treatment with vitamin E supplementation at 200 IU/kg chow. Two weeks later, all animals were sacrificed and the kidneys harvested. The secretory phospholipase A(2) (PLA(2)) activity was elevated (150%) in the untreated remnant kidney but returned to sham values in the vitamin E-treated kidneys. The cytoprotective heat shock protein (HSP70) and the intracellular antioxidant superoxide dismutase (MnSOD, Cu/ZnSOD) were similar in sham, remnant, and vitamin E-treated remnant kidneys. We conclude that the sudden reduction of renal mass secondary to the 5/6 nephrectomy procedure stimulates PLA(2) activity but not HSP70, MnSOD, or Cu/ZnSOD. This increased activity of PLA(2) in the remnant kidney returned to sham values after vitamin E treatment. The intrinsic cellular antioxidant enzymes, MnSOD, Cu/ZnSOD, as well as the cytoprotective heat shock protein HSP70, showed no significant changes in either vitamin E-treated or untreated kidneys compared with sham. These data are suggestive that the elevation of PLA(2) is a specific and localized response to the sudden reduction of renal mass.

Animals↗

PubMed2000

Gene expression after intrarenal injection of plasmid DNA in the rat.

Effective gene therapy requires efficient delivery and expression of the necessary genetic information to the target tissue. We demonstrate here that plasmid DNA, injected as naked, uncomplexed DNA into the cortical region of rat kidney, or intravenously, is localized and expressed in the kidney. The plasmid pRSVZ contained the Rous sarcoma virus promoter and a reporter gene, the beta-galactosidase gene, derived from bacteria. The beta-galactosidase gene hydrolyzes the artificial substrate X-gal to produce an intense blue color in cells that have taken up and expressed the plasmid genes. We have used X-gal staining and Western blotting to study plasmid gene expression 1, 4, and 8 days and 6 months after intrarenal injection of 50 microg of plasmid DNA and at 1 and 4 days after intravenous injection. Expression was apparent in the kidneys and several other tissues 24 h after injection and persisted for at least 8 days; expressed proteins could still be detected in the injected kidney 6 months later. These observations were corroborated by use of a plasmid, pEGFP-Puro, harboring the cytomegalovirus promoter in conjunction with a different reporter gene, the green fluorescent protein (GFP). Histological localization and Western blotting analysis of GFP expression after intrarenal injection of pEGFP-Puro paralleled results obtained with the plasmid pRSVZ. Our findings support the suggestion that intrarenal or intravenous injection of naked plasmid DNA may be an effective means of delivering therapeutic genes to the kidney and several other tissues.

Animals↗

PubMed2000

Different association of hypertension and insulin-related metabolic syndrome between men and women in 8437 nondiabetic Chinese.

Insulin resistance may cause a metabolic syndrome but whether insulin resistance causes hypertension is very controversial. Furthermore, it remains unclear whether the link between the insulin-resistance-related metabolic syndrome and hypertension is different between men and women. We examined fasting insulin, glucose, triglyceride and high-density lipoprotein (HDL)-cholesterol levels, systolic blood pressure, body mass index, and waist-to-hip ratio in a dataset from 8437 nondiabetic residents (age range, 30 to 89 years) in Kinmen. Factor analysis, a multivariate correlation statistical technique, was used to investigate the clustering and interdependence of these risk variables. Factor analysis identified two factors for men (n = 3659) and three factors for women (n = 4778, respectively. In men, a cluster of insulin, triglyceride, HDL-cholesterol, body mass index, and waist-to-hip ratio (metabolic syndrome) accounted for 29.7%, and a cluster of systolic blood pressure and glucose (hyperglycemia plus hypertension) accounted for 18.1% of the total variance in all variables considered. In women, a cluster of insulin, triglyceride, body mass index, waist-to-hip ratio, and systolic blood pressure (metabolic syndrome plus hypertension) accounted for 29.4%, a cluster of systolic blood pressure, glucose, and triglyceride (hyperglycemia plus hypertension plus dyslipidemia) accounted for 14.0%, and a cluster of triglyceride and HDL-cholesterol (dyslipidemia) accounted for 16.2% of the total variance. In conclusion, a distinct insulin-resistance-related metabolic syndrome characterized by hyperinsulinemia, dyslipidemia, and obesity was observed for both men and women in this Chinese population. However, hypertension was linked to the metabolic syndrome in women only.

Adult↗

PubMed2000

A small-molecule, tight-binding inhibitor of the integrin alpha(4)beta(1) blocks antigen-induced airway responses and inflammation in experimental asthma in sheep.

The leukocyte integrin very late antigen-4 (alpha(4)beta(1), CD49d/CD29) is an adhesion receptor that plays an important role in allergic inflammation and contributes to antigen-induced late responses (LAR) and airway hyperresponsiveness (AHR). In this study, we show that single doses of a new small-molecule, tight-binding inhibitor of alpha(4), BIO-1211, whether given by aerosol or intravenously, either before or 1.5 h after antigen challenge blocks allergen- induced LAR and post-antigen-induced AHR in allergic sheep. Multiple treatments with doses of BIO-1211 that were ineffective when given singly, were protective. BIO-1211 also provided dose-dependent inhibition of the early airway response (EAR) to antigen. In conjunction with the functional protection against the antigen-induced LAR and AHR, sheep treated with BIO-1211 before challenge showed significantly reduced: (1) numbers of eosinophils in bronchoalveolar lavage (BAL), (2) BAL levels of the inflammatory marker tissue kallikrein, and (3) numbers of inflammatory cells (lymphocytes, eosinophils, metachromatic staining cells, and neutrophils) in bronchial biopsies obtained after challenge when compared with corresponding biopsies after vehicle treatment. More importantly, we show for the first time that an inhibitor of alpha(4) was able to reverse post-antigen-induced AHR, thereby decreasing the time of recovery from the normal period of > 9 d to 3 d. Our results show that effective inhibition of antigen-induced airway responses can be achieved with single doses of a potent small-molecule inhibitor of alpha(4) and that such agents may be used therapeutically, as well as prophylactically, to alleviate allergen- induced inflammatory events. These data provide further support and extend the evidence for the role of alpha(4) integrins in the pathophysiologic events that follow airway antigen challenge.

Animals↗

PubMed2000

Association between chlorination of drinking water and adverse pregnancy outcome in Taiwan.

Chlorination has been the major means of disinfecting drinking water in Taiwan. The use of chlorinated water has been hypothesized to lead to several adverse birth outcomes, including low birth weight and preterm delivery. We performed a study to examine the relationship between the use of chlorinated water and adverse birth outcomes in Taiwan. The study areas included 14 chlorinating municipalities (CHMs), which were defined as municipalities in which > 90% of the municipal population was served by chlorinated water, and 14 matched nonchlorinating municipalities (NCHMs), defined as municipalities in which < 5% of the municipal population is served by chlorinated water. The CHMs and NCHMs were similar to one another in terms of level of urbanization and sociodemographic characteristics. The study population comprised 18,025 women residing in the 28 municipalities who had a first parity singleton birth between 1 January 1994 and 31 December 1996 and for which complete information on maternal age, education, gestational age, birth weight, and sex of the baby were available. The results of our study suggest that there was no association between consumption of chlorinated drinking water and the risk of low birth weight.

Adult↗

PubMed2000

Increase of leptin levels following exogenous administration of estrogen in women with normal menstruation.

To investigate the acute effect of exogenous estrogen on the changes of leptin production, the time sequence of changes in plasma leptin concentration were determined following i.v. administration of premarin, a conjugated estrogen, during the follicular phase (days 5-9) in women (n = 12) with normal menstruation. The mean circulating estradiol level abruptly (P < 0.0001) increased from 4 h to a level of 72-fold from baseline and was still significantly (P < 0.05) elevated at 72 h after injection of conjugated estrogen. The mean leptin level showed a significant (P < 0.05) gradual increase from 24 h (10.8 +/- 1.0 ng/mL) continuing on up to a peak at 32 h (11.6 +/- 0.9 ng/mL); significantly (P < 0.05) sustained to 48 h (10.7 +/- 0.7 ng/mL) and then slowly decreased at 56 h after injection of premarin, as compared with the preinjection level (7.8 +/- 0.7 ng/mL). However, there were no changes of leptin levels in women (n = 10) who received normal saline injection. These data clearly suggest that a higher level of estrogen could stimulate the increase of plasma leptin concentration during the follicular phase of normal cyclic women. This result provides evidence that supraphysiological level of estrogen may act on the adipocyte to modulate leptin production through the endocrine mechanism.

Adult↗

PubMed2000

Community based epidemiological study on hyperuricemia and gout in Kin-Hu, Kinmen.

OBJECTIVE: This is a population survey conducted in 1991-92 among residents aged > or =30 years in Kin-Hu, Kinmen, with a 77.7% response rate to study the prevalence of hyperuricemia and hyperuricemia associated gout. A stratified analysis based on sex and age was used to assess the interaction and analyze the associated risk factors for hyperuricemia and gout. METHODS: Hyperuricemia was defined as uric acid > or =7.0 mg/dl for men and > or =6.0 mg/dl for women. Gout was clinically diagnosed by a senior rheumatologist based on patient's history and examination according to the clinical criteria of Wallace. Basic demographic and lifestyle variables as well as biochemical data were collected. RESULTS: The prevalence of hyperuricemia was 25.8% (391/1515) in men and 15.0% (250/1670) in women. The prevalence of gout among hyperuricemic subjects was 11.5% for men and 3% for women. According to age spectrum, the risk factor for hyperuricemia was hyperlipidemia in young adults (30-39 yrs); lifestyle and some clinical syndromes played a significant role in middle aged persons (40-59 yrs). The different risk factors between the sexes in middle age were alcohol consumption effect in men and menopause effect in women. Impaired renal function and use of diuretics became the important factors in the elderly (> or =60 yrs). The risk factors for gout among either the general population or subjects with hyperuricemia were concentration of serum uric acid, alcohol consumption, and central obesity. CONCLUSION: Risk factors for hyperuricemia tended to be different with respect to sex and age. Alcohol consumption and central obesity were independent predictors of gout among hyperuricemic subjects irrespective of uric acid level.

Adult↗

PubMed2000

The interaction between uric acid level and other risk factors on the development of gout among asymptomatic hyperuricemic men in a prospective study.

OBJECTIVE: To investigate the incidence of gout and the interaction between uric acid level and other risk factors in the development of gout. METHODS: Two hundred twenty-three asymptomatic hyperuricemic men initially studied in 1991-92 were reassessed in 1996-97. Gout was clinically diagnosed by a senior rheumatologist based on history and physical according to the clinical criteria of Wallace. Basic demographic and lifestyle variables as well as biochemical data were collected in both baseline and followup periods. Both the stability analysis and the analysis of repeated relationships were applied. RESULTS: The 5-year cumulative incidence of gout was 18.83% (42/223). The risk factors for gout based on the analysis of repeated relationships were uric acid level, alcohol consumption, use of diuretics, and obesity. The only predictor of gout at baseline was uric acid level. After adjusting for baseline uric acid level, followup uric acid increase, persistent alcohol consumption, use of diuretics in the followup period, and body mass index increase were independent predictors for gout among asymptomatic hyperuricemic men. Excessive alcohol consumption, particularly if occasional, was the most important factor in the development of gout, even when the concentration of uric acid level was below 8 mg/dl. CONCLUSION: Uric acid level is the key factor for prevention of gout and needs constant monitoring. Other contributing or possible etiologic factors such as alcohol consumption, diuretics use, and excess weight gain carry an increased risk of gout attack among patients with hyperuricemia.

Adult↗

PubMed1999

Laser-enhanced ionization detection of Pb in seawater by flow injection analysis with on-line preconcentration and separation.

The flame laser-enhanced ionization (LEI) technique is coupled with the flow injection analysis system to measure the trace lead amounts in aqueous solution and in seawater. The flow injection (FI) manifold is incorporated with a microcolumn packed with a C18 bonded silica. The chelating agent DDPA is used to form the Pb-DDPA complex, which may be sorbed in the microcolumn and then eluted with methanol. The preconcentrated Pb is then detected by the LEI technique with either single-step or two-step excitation. At 5- and 15-mL volume-fixed sample loading, the detection limits of 0.011 and 0.0033 ng/mL (11 and 3.3 ppt) and enrichment factors of 16 and 48 are achieved, respectively, using a two-step FI-LEI. The sensitivity of the current system proves to be better by at least 1 order of magnitude than that of conventional LEI method. The FI-LEI also increases the tolerance of matrix interference. The LEI signal is slightly reduced to 80% intensity as 10,000 micrograms/mL (ppm) Na and K matrixes are mixed in the lead solution. The resistance to the alkali matrixes is enhanced approximately 4 times that reported previously using a similar water-immersed probe as a LEI collector. Finally, the FI-LEI is for the first time applied to detect the Pb content in seawater, achieving a result of 0.0112 +/- 0.0006 ng/mL (ppb) consistent with the certified value of 0.013 +/- 0.005 ng/mL (ppb).

Flame Ionization↗

PubMed1999

Bilateral periopticointrascleral hemorrhages associated with traumatic child abuse.

PURPOSE: To report a case of bilateral periopticoscleral hemorrhages associated with traumatic child abuse. METHODS: Postmortem gross examination and histopathologic studies of both eyes and the optic nerves of a 6-month-old infant who died from subdural hematoma. RESULTS: Gross examination and histopathologic step sections disclosed bilateral intrascleral hemorrhages around both optic nerves. In addition, bilateral diffuse multilayered retinal, vitreous, and sublaminar (beneath the internal limiting membrane) hemorrhages were present. CONCLUSION: Periopticointrascleral hemorrhages are characteristic of blunt head trauma and may constitute important forensic evidence in cases of suspected child abuse.

Battered Child Syndrome↗

PubMed1999

Lipoleiomyoma of the uterus.

Uterine lipoleiomyoma may associate with certain concomitant metabolic disorders. The possible clinical correlates and the potential implications on the pathogenesis are elaborated.

Female↗

PubMed1999

Changes of circulating leptin levels during normal menstrual cycle: relationship to estradiol and progesterone.

A possible role of ovarian steroids on the modulation of leptin production has recently been suggested. To investigate the relationship between leptin and ovarian steroids during the normal menstrual cycle, twenty-three healthy, normal-weight women were enrolled in the study. Blood was collected into chilled EDTA tubes on cycle days (D) 3, 7, 10, preovulatory (D13-15), midluteal (D 21-23) and late luteal (D 25-27) phases. Plasma leptin, estradiol (E2), progesterone (P), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured by RIA. Leptin levels showed no significant changes throughout the follicular (D7 and D10), preovulatory (8.6 +/- 0.5 ng/mL), midluteal (8.9 +/- 0.6 ng/mL) and late luteal (7.7 +/- 0.4 ng/mL) phases, as compared with those of D3 (7.4 +/- 0.5 ng/mL) level. There was no positive correlation between leptin and E2 levels in D 3 and D 7 (r = 0.14, P > 0.05) or in D 10 and preovulatory day (r = 0.25, P > 0.05). Also, no positive correlation between leptin and E2 (r = 0.12, P > 0.05) or leptin and P (r = 0.17, P > 0.05) levels were observed in the mid- and late luteal phases. These data clearly indicate that physiological alterations of circulating E2 and P concentrations have no significant influence on the leptin changes during normal menstrual cycle.

Adult↗

PubMed1999

Increase of maternal plasma leptin concentrations during pregnancy: comparison with nonpregnant women.

To investigate the physiological changes of leptin levels and whether placenta is linked to its production during pregnancy, plasma of 65 pregnant women at various gestational weeks were compared with those of 34 age- and body mass index (BMI)-matched nonpregnant women in the study. The leptin levels showed a gradual increase from 7-13 gestational week, then continuously elevated during weeks 14-20, 21-27, 28-34, virtually reaching a peak at 35-41 weeks' gestation. When they were compared to those of age- and BMI-matched nonpregnant women, a significant (P < 0.0001) increase was found with every gestational week. There were positive correlations between maternal leptin and BMI of first (7-13th week), second (14-27th week) and third (28-41st week) trimesters, with the correlation coefficients of 0.40 (P < 0.05), 0.54 (P < 0.001), and 0.49 (P < 0.001), respectively. No correlation (r = -0.17, P > 0.05, n = 31) was found between maternal leptin level and the neonatal birth weight. These data suggest that placental production of leptin is one major source of higher levels in maternal circulating leptin other than maternal gain of fat mass and that maternal leptin level is not related to fetal birth weight during pregnancy.

Adult↗

PubMed1999

Difference of plasma leptin levels in venous and arterial cord blood: relation to neonatal and placental weight.

To investigate the physiological significance of umbilical plasma leptin in the fetal growth and its possible origin of production during pregnancy, plasma leptin concentrations in venous and arterial cord bloods were measured in 42 neonates (male = 23, female = 19, gestational age 36-41 weeks, birth weight 2600-4000 g). Leptin concentrations in umbilical veins (5.65 +/- 0.53 ng/mL, n = 42) and umbilical arteries (0.56 +/- 0.07 ng/mL, n = 42) were significantly (P < 0.001) lower than those in maternal peripheral veins (22.36 +/- 1.06 ng/mL, n = 42). Mean plasma leptin concentration (+/- SEM) in venous cord blood was significantly (P < 0.001) higher than that of arterial cord blood. There was significantly positive correlation (r = 0.447, P < 0.01) between umbilical venous leptin levels and neonatal body mass index (BMI). A positive correlation (r = 0.435, P < 0.01) was also found between umbilical arterial leptin and neonate BMI. There was no positive correlation between umbilical leptin levels in venous cord blood and placental weight. We thus conclude that umbilical plasma leptin may play an essential role in the fetal growth and metabolism during pregnancy and placenta is one of the major sources of leptin production, but the level of leptin in umbilico-placental circulation is independent of the weight of placenta.

Adult↗

PubMed1998

Increased heat shock protein-70 in unilateral ureteral obstruction in rats.

Our previous studies noted the oxidative stress of unilateral ureteral obstruction (UUO). Now, we seek to explore whether UUO affects the intrinsic cellular antioxidants and triggers heat shock protein (HSP-70) and whether these are still highly expressed after reversal of the UUO (R-UUO). In addition, we designed the experiment to determine whether this expression of HSP-70 is a localized or a generalized response. Male Sprague-Dawley rats (125-150 g) were randomly assigned to sham operation, left UUO, or R-UUO procedures at six rats per group. The sham, UUO, and R-UUO animals were studied 10 days after UUO or 7 days after R-UUO. A clear increase in the left (obstructed) kidney's malondialdehyde (MDA), a marker of lipid peroxidation, was observed: a significant 2.6-fold of sham during UUO and a 1.7-fold of sham in R-UUO. The contralateral (unobstructed) right kidney showed a significant rise in MDA during UUO, but during R-UUO the MDA had fallen back to sham values. It is possibly the result of a systemic effect from the free radicals produced by the oxidative stress of the UUO. The antioxidant enzyme, manganese superoxide dismutase (MnSOD) of the left, obstructed kidney showed a significant reduction in UUO compared to that of the sham. Upon reversal of UUO (R-UUO), MnSOD was lower than that of the sham. The left kidney's HSP-70 increased during UUO and was 3.7-fold that of sham (P < 0.05) but, during R-UUO, was not different from sham (P, ns). The contralateral (intact) right kidneys' HSP-70 showed no change between sham, UUO, and R-UUO states. We conclude that UUO gives rise to oxidative stress which is generalized in both the obstructed and the contralateral unobstructed kidney, as indicated by the elevation in kidney MDA content in both kidneys. The intrinsic cellular antioxidant enzyme, manganese superoxide dismutase, showed a significant and generalized reduction in both UUO and R-UUO. In contrast, the HSP-70 was markedly elevated only in the obstructed kidney and not in the R-UUO or in the contralateral kidney, suggesting that the elevation of HSP-70 is a specific and localized response to oxidative injury of UUO.

Animals↗

PubMed1998

Starvation depresses acylglycerol biosynthesis in bovine subcutaneous but not intramuscular adipose tissue homogenates.

The primary objective of this study was to document the effects of starvation on acylglycerol biosynthesis in homogenates of intramuscular and subcutaneous adipose tissues. Adipose tissue samples were obtained from 8th-13th thoracic rib sections from 12 Angus cattle (six steers plus six heifers). Three steers and three heifers were starved for 72 h prior to slaughter while the remainder were slaughtered 4 h after food was withheld. Fat-free 700 x g centrifugal fractions were used to measure the esterification of radiolabeled sn-glycerol 3-phosphate (G-3-P) into acylglycerols at 1.0 mM palmitic or stearic acid, or 0.2 mM oleic, linoleic, or alpha-linolenic acid. There were significant tissue x fatty acid interactions for rates of incorporation into diacylglycerols and triacylglycerols; in subcutaneous, but not intramuscular homogenates, palmitic > stearic = oleic = linoleic = alpha-linolenic acid. Subcutaneous homogenates incorporated a greater percentage of G-3-P into triacylglycerols, and a lesser percentage into phospholipid, than intramuscular homogenates (P < 0.05). In intramuscular homogenates, the primary product of G-3-P esterification to saturated fatty acids was phospholipids. When unsaturated fatty acid served as substrates, triacylglycerols and phospholipids were produced in equal proportions in intramuscular homogenates, and triacylglycerols were the predominant product in subcutaneous homogenates. Intramuscular adipose tissue homogenates exhibited no response to starvation, whereas triacylglycerol and diacylglycerol synthesis was depressed by approximately 50% in subcutaneous adipose tissue homogenates. Similarly, phosphatidic phosphohydrolase activity, initially greater in subcutaneous than in intramuscular adipose tissue, was decreased by approximately 50% by starvation in subcutaneous adipose tissue, but not in intramuscular adipose tissue. We conclude that differences in rates of diacylglycerol and triacylglycerol biosynthesis, and response to starvation, between intramuscular and subcutaneous adipose tissues were due to dissimilarities in the activity of phosphatidic phosphohydrolase.

Adipose Tissue↗

PubMed1998

Very late antigen 4 (VLA4) antagonists as anti-inflammatory agents.

In recent years antagonists of very late antigen-4 (VLA4, also known as integrin alpha(4) beta(1)) have shown great promise in treating inflammatory disorders in a number of animal models. The most advanced in this endeavor is a humanized anti-alpha(4) antibody, Antegren, which is in phase II clinical trials for multiple sclerosis. The first reported small-molecule VLA4 antagonist to advance into clinical trials is currently in phase I as an aerosol for treating asthma. A number of peptides, cyclic peptides and peptidomimetics have been disclosed and are in preliminary stages of development.

Amino Acid Sequence↗

PubMed1998

Localization of persistent Enterocytozoon bieneusi infection in normal rhesus macaques (Macaca mulatta) to the hepatobiliary tree.

Enterocytozoon bieneusi is the most common microsporidian parasite recognized in human patients with AIDS. Recently, we identified a virtually identical organism causing a spontaneous infection associated with hepatobiliary and intestinal disease in simian immunodeficiency virus (SIV)-infected macaques. To examine the natural history of the infection, we examined captive rhesus macaques for E. bieneusi by PCR, in situ hybridization, and cytochemical techniques. PCR performed on fecal DNA detected enterocytozoon infection in 22 (16.7%) of 131 normal rhesus macaques (Macaca mulatta), compared to 18 (33.8%) of 53 rhesus macaques experimentally inoculated with SIV. In normal rhesus macaques, persistence of infection was demonstrated for up to 262 days and was usually not associated with clinical signs. In six of seven normal rhesus animals, E. bieneusi was detected by PCR in bile obtained through percutaneous cholecystocentesis but not by in situ hybridization performed on endoscopic biopsies of duodenum and proximal jejunum.

Animals↗