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Biomedical subjects

S S Lin

Publications and source records attributed to S S Lin.

At least 91 records · Page 5Linked to original sources
PubMed1996

Effects of gypenosides on cellular immunity of gamma-ray-irradiated mice.

OBJECTIVE: To investigate the effects of gypenosides (Gs) on cellular immunocompetence in the gamma-ray-irradiated mice. MATERIALS AND METHODS: Tested mice of ICR strain were treated continuously with Gs for 10 days before or after 4 Gy gamma-irradiation. Body weight and splenic weight of mice were measured. The blastogenic response of splenocytes to mitogens, such as PHA, Con A and LPS were also detected. The cellular immunocompetence was measured by 3H-thymidine incorporation in each tested mouse. RESULTS: Body weight as well as splenic weight decreased in gamma-ray-irradiated mice. The blastogenic responses of splenocytes to mitogens were inhibited after gamma-ray irradiation. To treat with Gs was effective to enhance the recovery of body weight, splenic weight and immunocompetence in gamma-ray-irradiated mice from radiation damage. CONCLUSIONS: Four Gy gamma-ray irradiation could decrease splenic weight and cellular immunocompetence of mice. Gs could help the recovery of the splenic weight and cellular immunocompetence in gamma-ray-irradiated mice.

Animals↗
PubMed1995

Pressure and volume loading of the right ventricle have opposite effects on left ventricular ejection fraction.

BACKGROUND: Left ventricular ejection fraction has been reported to be depressed in patients with right ventricular volume overload (RVVO) due to Ebstein's anomaly and uncomplicated atrial septal defect, whereas it is usually preserved in right ventricular pressure overload (RVPO) due to congenital pulmonic stenosis. In the present study, we examined the hypothesis that the differential timing of active displacement of the ventricular septum into the left ventricle in RVPO (end systole) and RVVO (end diastole) results in opposite effects of RVPO and RVVO on left ventricular ejection fraction. METHODS AND RESULTS: Ten patients with severe tricuspid regurgitation after tricuspid valve resection for endocarditis and 10 patients with primary pulmonary hypertension were studied as models of isolated RVVO and RVPO, respectively. Left ventricular ejection fraction, end-diastolic volume, and regional systolic shortening were measured with the use of echocardiographic techniques in these 20 patients and 10 healthy control subjects. In RVPO, despite marked underfilling of the left ventricle relative to the healthy control subjects (end-diastolic volume, 48 +/- 26 versus 77 +/- 20 mL; P < .02), left ventricular ejection fraction was similar to that of the control subjects (56 +/- 5% versus 60 +/- 4%; P = .07) and only 1 of 10 RVPO patients had an ejection fraction of less than 50%. In contrast, in RVVO the left ventricle was volume replete (end-diastolic volume, 84 +/- 26 versus 77 +/- 20 mL; P = NS), but left ventricular ejection fraction was significantly depressed (51 +/- 4% versus 60 +/- 4%, P < .001) compared with the control subjects, and 4 of 10 RVVO patients had an ejection fraction of less than 50%. Analysis of systolic fractional shortening along two perpendicular short-axis diameters and the mutually orthogonal long axis demonstrated isolated augmentation of fractional shortening in the ventricular septal-to-posterolateral free wall dimension in RVPO (47.4 +/- 13.7% versus 34.2 +/- 13.1%, P < .05) and isolated depression of fractional shortening along that same dimension in RVVO (13.7 +/- 11.8% versus 34.2 +/- 13.1%, P < .001) compared with the control subjects. CONCLUSIONS: End-systolic leftward ventricular septal shift in RVPO results in isolated augmentation of systolic shortening in the septal-to-free wall dimension, whereas end-diastolic leftward ventricular septal shift in RVVO results in isolated reduction in systolic shortening in the septal-to-free wall dimension. As a result, despite relative underfilling of the left ventricle in RVPO, resting left ventricular ejection fraction is preserved, whereas ejection fraction is depressed for the volume-replete left ventricle of patients with RVVO.

Adolescent↗
PubMed1995

Cellular proteins specifically bind to the 5'-noncoding region of hepatitis C virus RNA.

Hepatitis C virus (HCV) RNA contains a highly conserved 5'-noncoding region (5'NCR) which may be important in viral multiplication. To study the possible mechanisms of the cellular proteins involved in HCV replication and pathogenesis, a gel mobility shift assay and competition analysis were performed with the HCV 5'NCR. Two specific complexes were formed between the 341-nucleotide RNA of the HCV 5'NCR and proteins of mammalian cells. The specific RNA-protein complexes were maintained in the region of the 5'NCR from nucleotides 131 to 253. Nevertheless, the slower migrating RNA-protein complex failed to form when a polypyrimidine tract sequence (191-UCCUUUCUU-199) in the stem-loop III structure of HCV 5'NCR was changed to 191-UCCUUUggU-199. A uv cross-linking assay further identified two cellular proteins, p87 and p120, that specifically bound to the stem-loop III structure. Mutations at the polypyrimidine tract sequence inhibited the binding of p87, but maintained the ability of the mutant HCV RNA to interact with p120. Translation competition assay demonstrated that the 5'NCR from nt 131 to 253 within the stem-loop III structure is important for the translation of HCV core protein. In addition, p120 and unidentified cellular proteins are likely to be involved in the translation of HCV polyprotein, whereas p87 may play important roles in HCV multiplication other than translation.

Animals↗
PubMed1995

Low-velocity gunshot wounds to the spine with an associated transperitoneal injury.

Twenty-nine patients who incurred a transperitoneal low-velocity gunshot wound to their spine were evaluated for the occurrence of spinal infectious complications. All patients underwent an exploratory laparotomy to determine the extent of viscera involvement. No attempt was made to debride the involved spinal area, and the bullet was not removed unless it was easily accessible. Of the 21 patients with a parenchymal and/or noncolonic viscous injury, 17 (77%) were treated with intravenous (i.v.) antibiotics for a minimum of 5 days the remainder received treatment for a maximum of 48 h. All 8 patients with colonic injuries received a minimum of > or = 5 days of antibiotic treatment. Follow-up averaged 44.9 months (range 3-144 months). Only 1 (4.7%) patient with either a noncolonic or parenchymal perforation developed an infectious complication (subdiaphragmatic abscess); two patients (25%) with colonic perforations developed a psoas abscess. No patient developed a spinal infection. This study suggests that patients who sustain a transperitoneal low-velocity gunshot wound to their spine do not need to undergo spinal debridement and may be treated with parenteral antibiotics. Any course of broad-spectrum antibiotics for 5 days appears to minimize infectious complications. Bullet removal and missile tract debridement of the spine is not routinely necessary.

Adolescent↗
PubMed1995

Determination of free digoxin in sera of 8 patients with chronic cardiac insufficiency.

AIM: To establish a method for the determination of free digoxin in serum for clinical use and to study the relationship between the free and total digoxin concentrations in chronic cardiac insufficiency patients receiving digoxin with different renal function. METHODS: The ultrafiltration with fluorescence polarization immunoassay was used to determine the concentration of free digoxin. RESULTS: The concentrations of digoxin standards in serum were 0.96, 1.92, and 3.84 nmol.L-1. The relative standard deviation was < 7% for intra-day and < 6% for inter-day determinations. The average recovery was 99.95 +/- 2.18%. The ratio of free/total digoxin in chronic cardiac insufficiency patients with renal dysfunction was lower than that in patients with normal kidneys (63.5 +/- 4.7% vs 75.1 +/- 3.9%, P < 0.01). CONCLUSION: The present method is simple and reliable. In these patients there is an over-measurement for total digoxin concentration, suggesting the presence of elevated endogenous digoxin-like immunoreactive substances.

Aged↗
PubMed1994

Transdural cortical stabbing facilitates the drainage of edema fluid out of cold-injured brain.

Recent experimental results indicate that cerebral glia lining and glia limitans may be barriers for plasma protein extravasated from injured cerebral microvessels flowing into the adjacent subarachnoid space. Therefore, it has been hypothesized that a transdural cortical stabbing which opens both the pia lining and glia limitans may facilitate drainage of edema fluid into the subarachnoid space and minimize brain edema. This hypothesis was tested in Sprague-Dawley rats with a transdural cold-injury on the right parietal cortex. The animals were sacrificed 24 hours later. One hour before being sacrificed 0.6 ml of 2% Evans blue was intravenously injected to determining the Evans blue distribution area. For measuring the inulin retention volume in the brain, 14C-inulin (10 microCi) in 1 ml of saline was injected intravenously at 10 min before sacrifice. The extent of brain edema was assessed by measuring the water content, the inulin retention volume, and the distribution area of Evans blue in the brain. Our results showed that the transdural cortical stabbing did not alter the water content of the cerebral hemisphere with cold lesion. However, it did effectively diminish the inulin retention volume by 26% as well as the distribution area of Evans blue by 22% in the cerebral hemisphere with cold lesion. In conclusion, a transdural cortical stabbing on the injured cortex may be beneficial for vasogenic brain edema.

Animals↗
PubMed1994

Fibroblasts isolated from human pterygia exhibit transformed cell characteristics.

Pterygium is a degenerative corneal limbal process and UV irradiation has been suggested as being a major environmental predisposing factor. The invasive nature of the fibroblasts associated with pterygia raises the question as to whether these cells are transformed. To test this hypothesis, we established fibroblast strains from autologous and heterologous pterygial and conjunctival specimens, respectively, from subjects between 40 to 50 yr of age, and compared their growth characteristics in culture. All pterygial fibroblast strains exhibited a reduced dependence on serum and exogenous growth factors for growth and reached a saturation population density that was threefold higher than conjunctival fibroblasts cultured under the same conditions. In addition, all pterygial fibroblast strains were able to form colonies in soft agar in 5% fetal bovine serum at a 6.0 to 7.5% efficiency. Under the same experimental conditions, none of the conjunctival fibroblast strains were able to grow. The results presented support the conclusion that pterygial fibroblasts have acquired many of the properties of the transformed phenotype.

Adult↗
PubMed1994

Cerebral effects of nitrous oxide during isoflurane-induced hypotension in the pig.

We have studied the effects of nitrous oxide on cerebral blood flow (CBF), cerebral blood flow velocity (CBFV) and intracranial pressure (ICP) during isoflurane-induced hypotension in 10 pigs. CBF was measured using laser Doppler flowmetry, CBFV in the right middle cerebral artery was calculated using Doppler ultrasound and ICP was measured using an extradural ICP monitor. Each animal was studied under four conditions, examined sequentially: (i) mean intra-arterial pressure (MAP) 85 mm Hg, maintained with isoflurane, (ii) MAP 50-55 mm Hg, induced by isoflurane only, (iii) MAP 85 mm Hg, maintained with isoflurane and 50% nitrous oxide, and (iv) MAP 50-55 mm Hg, induced by isoflurane and 50% nitrous oxide. No significant differences were noted between conditions with respect to ICP. There was a significant difference in CBF during condition (ii) compared with (i) (mean 75(SD 21) vs 100(0)%) and during condition (iv) compared with (iii) (90(26) vs 109(13)%). Animals under condition (iv) exhibited a 20% reduction in CBFV compared with those under condition (iii) (57 vs 69 cm s-1). For animals under normotensive conditions, addition of nitrous oxide to isoflurane resulted in a 16% increase in CBFV (69 vs 60 cm s-1). Comparing isoflurane-induced hypotension ((ii) vs (iv)), there was no statistical difference in either CBF or CBFV on addition of 50% nitrous oxide. The correlation between changes in CBF and CBFV was not significant. We conclude that the use of nitrous oxide during isoflurane-induced hypotension has no significant effect on CBF, CBFV or ICP compared with the use of isoflurane alone.

Animals↗
PubMed1994

Right ventricular volume overload results in depression of left ventricular ejection fraction. Implications for the surgical management of tricuspid valve disease.

BACKGROUND: Right ventricular volume overload (RVVO) occurring in conditions such as Ebstein's anomaly may result in depression of left ventricular ejection fraction (LVEF). This study tests this hypothesis by measuring LVEF in 10 patients with RVVO due to tricuspid valve resection for isolated tricuspid valve endocarditis and in 10 age-matched healthy persons. METHODS AND RESULTS: When the modified Simpson's rule was applied to echocardiographic images, LVEF for patients with RVVO measured significantly lower than for age-matched healthy subjects (51 +/- 4% versus 60 +/- 4%, P < .0001). Depression of LVEF does not result simply from reduced venous return to the left ventricle, since left ventricular end-diastolic volume was not significantly different between patients with RVVO and age-matched healthy persons (84 +/- 26 versus 77 +/- 20 mL, NS). Possible explanations for the depression in LVEF may relate to the decreased relative contribution of left atrial systole to left ventricular filling (demonstrated by transmitral pulsed Doppler) or to the mechanical effects of ventricular septal paradox (demonstrated by the abnormal leftward ventricular septal flattening and increase in short-axis cavity eccentricity at end diastole, which returns to normal at end systole) in patients with RVVO. CONCLUSIONS: These findings suggest that surgical excision of the tricuspid valve results in isolated RVVO, which creates not only diastolic overload of the right heart but also depression of LVEF.

Adult↗
PubMed1994

Pain on injection of propofol.

A controlled randomized double-blinded clinical study was undertaken to evaluate and compare the efficacy of three methods of preventing pain during injection of propofol on induction of anesthesia. Patients were randomly allocated to six groups: saline pretreatment, followed by induction with propofol at room temperature plus saline; lidocaine pretreatment, followed by induction with propofol at room temperature plus saline; saline pretreatment, followed by induction with propofol at a temperature of 4 degrees C plus saline; lidocaine pretreatment, followed by induction with propofol at a temperature of 4 degrees C plus saline; saline pretreatment, followed by induction with propofol at room temperature plus lidocaine 40 mg; saline pretreatment, followed by induction with propofol at a temperature of 4 degrees C plus lidocaine 40 mg. Pretreatment with lidocaine reduced the incidence of pain and discomfort significantly compared with unpretreated groups. Groups which received propofol mixed with lidocaine also showed a significant reduced incidence of pain. induction with cold 4 degrees C propofol showed no significant difference in reduction of injection pain.

Adult↗
PubMed1993

Stimulation or inhibition of A431 cell growth by EGF is directly correlated with receptor tyrosine kinase concentration but not with PLC gamma activity.

EGF-induced hydrolysis of phosphatidylinositol 4, 5, biphosphate was compared in A431 cells with respect to their growth response to EGF. A431 cells which express 4- to 5-fold more EGF receptors than A431-4 cells were growth inhibited, while A431-4 cells were growth stimulated by EGF within the same dose range. Treatment of A431 cells with EGF resulted in a 2-fold increase in cellular IP3 levels and the effect in A431-4 cells was not as obvious. In the presence of tyrosine kinase inhibitor coumaric acid (0.2 approximately 2 microM), A431 cell growth was stimulated, rather than inhibited, by EGF in a dose-dependent manner. In contrast, the stimulation of A431-4 cell growth by EGF was reduced under the same conditions. Furthermore, in the presence of coumaric acid (up to 0.5 microM), EGF-induced production of inositol phosphates in A431 cells was not obviously affected. Taken together, the results suggest that EGF-induced growth inhibition of A431 cells may be due to a quantitative changes of EGF-receptor tyrosine kinase activity in areas other than the recruitment and activation of phosphatidylinositol-specific phospholipase C gamma.

Carcinoma, Squamous Cell↗
PubMed1993

Partial purification and characterization of soluble acid invertases from rice (Oryza sativa) leaves.

There are three soluble acid invertases in the leaves of rice. They could be separated by DEAE1-Sephacel chromatography, and named IT1, IT2 and IT3. The molecular weights of IT1, IT2 and IT3, determined by HPLC gel filtration chromatography, were 220 kD, 59 kD and 67 kD, respectively. Their pI values were 6.2, 5.2 and 4.9, respectively. The pH optima of IT1, IT2 and IT3 were 3.5, 6.0 and 5.5 respectively. All of them could hydrolyze sucrose and raffinose but not maltose, therefore they are all beta-fructofuranosidases. The apparent Km values for sucrose and raffinose of IT3 were 7.0 and 14.5 mM, respectively. Exogenous protein BSA could activate IT3. IT3 was inhibited by metal ions--Pb2+, Zn2+, Cu2+, Hg2+ and Ag+. The sulfhydryl group inhibitor, PCMB, and serine protease inhibitor, PMSF, had no effects on IT3 activity. It might indicate that cysteine and serine did not participate directly the active site catalytic reaction of IT3.

Cations, Divalent↗
PubMed1992

Reversal by pertussis toxin and N-ethylmaleimide of the facilitation of baroreceptor reflex response by somatostatin in the rat.

We evaluated the transmembrane signaling mechanism that may underlie the facilitatory action of somatostatin (SOM) on baroreceptor reflex (BRR), using adult, male, Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p.). Intracerebroventricular (i.c.v.) application of SOM (2 nmol) promoted a significant elevation in BRR response, induced by phenylephrine (5 micrograms/kg, i.v.). This potentiatory action of the tetradecapeptide was significantly reversed after pretreating animals with bilateral microinjection of pertussis toxin (25 ng) or N-ethylmaleimide (2 nmol) into the nucleus tractus solitarius (NTS), the terminal site for baroreceptor afferents. These results suggest that a pertussis toxin-sensitive GTP-binding regulatory protein, possibly Gi, may be involved in the modulation of the BRR by SOM at the NTS.

Afferent Pathways↗
PubMed1992

Effect of premedication on the changes of neuropeptide Y (NPY) in anesthesia.

Premedication is one of the popular techniques in anesthesia, not only for the decrease of side effects but also for the increase of actions. Clinically, we found that plasma neuropeptide Y-like immunoreactivity (NPY-IR) was lowered in patients who had received premedication. In rats, plasma NPY-IR was not modified by the intravenous injection of diazepam. Pethidine reduced the plasma NPY-IR level which could be reversed by naloxone. Direct inhibition of plasma NPY-IR through an activation of opioid receptors can thus be considered. To the cold-stress stimulation, plasma NPY-IR was markedly raised. Diazepam reduced this stimulation-induced increase of plasma NPY-IR in a dose-dependent manner. Similar derivative of benzodiazepine produced an inhibition in a way following the potency as that to produce anxiolytic action. Also, this inhibition was reversed by PK11195, an antagonist of peripheral benzodiazepine receptors. Moreover, pain-stimulated increase of plasma NPY-IR in rats was also reduced by pethidine. This action was totally reversed in the presence of naloxone, indicating the participation of opioid receptors in the process. The obtained results suggest that premedication of diazepam and/or pethidine has the ability to decrease plasma NPY-IR in animals.

Animals↗
PubMed1991

Facilitation of baroreceptor reflex response by endogenous somatostatin in the rat.

We evaluated the potential participation of endogenous brain somatostatin-14 (SOM) in central cardiovascular regulation, using adult male Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p.). Intracerebroventricular (i.c.v.) application of SOM (2 or 4 nmol) promoted a significant elevation in baroreceptor reflex (BRR) response, induced by phenylephrine (5 micrograms kg, i.v.). Blocking the endogenous SOM activity with its specific receptor antagonist, cyclo-[7-aminoheptanoyl-Phe-D-Trp-Lys-Thr(Bzl)] (2 or 4 nmol, i.c.v.) or antiserum against SOM (1:20, i.c.v.), on the other hand, appreciably attenuated the same response. These modulatory effects on the BRR response were essentially duplicated upon bilateral microinjections of SOM (320 pmol), SOM antagonist (320 pmol) or anti-SOM (1:20) into the caudal portion of the nucleus of tractus solitarius (NTS), the terminal site for baroreceptor afferents. These results suggest that neurons that contain SOM may participate in cardiovascular control by tonically facilitating the BRR, possibly by exerting an influence on the neurons at the NTS.

Animals↗