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Biomedical subjects

S L Lin

Publications and source records attributed to S L Lin.

At least 37 records · Page 2Linked to original sources

Activation of extracellular signal-regulated kinase (ERK) and Akt by human serotonin 5-HT(1B) receptors in transfected BE(2)-C neuroblastoma cells is inhibited by RGS4.

Regulator of G protein signaling (RGS) proteins are GTPase-activating proteins for heterotrimeric G proteins. One of the best-studied RGS proteins, RGS4, accelerates the rate of GTP hydrolysis by all G(i) and G(q) alpha subunits yet has been shown to exhibit receptor selectivity. Although RGS4 is expressed primarily in brain, its effect on modulating the activity of serotonergic receptors has not yet been reported. In the present study, transfected BE(2)-C human neuroblastoma cells expressing human 5-HT(1B) receptors were used to demonstrate that RGS4 can inhibit the coupling of 5-HT(1B) receptors to cellular signals. Serotonin and sumatriptan were found to stimulate activation of extracellular signal-regulated kinase. This activation was attenuated, but not completely inhibited, by RGS4. Similar inhibition by RGS4 of the protein kinase Akt was also observed. As RGS4 is expressed at high levels in brain, these results suggest that it may play a role in regulating serotonergic pathways.

Calcium-Calmodulin-Dependent Protein Kinases↗

Choledochal cyst associated with acute acalculous cholecystitis.

A 7-year-old girl underwent laparotomy for suspected acute appendicitis. Instead, bile peritonitis with hydrops of gallbladder and normal appendix were noted. Dilatation of the CBD was observed, and choledochal cyst was documented by intraoperative cholangiography. Cholecystectomy and T-tube placement were performed. Postoperative follow-up by ultrasound lasted for 9 months. The CBD remained the same size without clinical manifestation.

Acute Disease↗

Tumor amplified protein expression therapy: Salmonella as a tumor-selective protein delivery vector.

Attenuated strains of Salmonella typhimurium, VNP20009 and YS7212, when injected systemically to tumor-bearing mice, accumulated preferentially in tumors at levels at least 200-fold and, more commonly, 1000-fold greater than in other normal tissues. This selectivity occurred in subcutaneously implanted murine tumors, including B16F10 melanoma, M27 lung carcinoma, and colon 38 carcinoma. The preferential accumulation was also manifested in animals bearing human tumor xenografts, including Lox, C8186, DLD1, SW620, HCT116, HTB177, DU145, MDA-MB-231, and Caki. Four to five days after a single IV injection of 1 x 10(6) colony-forming unit (cfu)/mouse, we routinely detected VNP20009 proliferation and accumulation at levels ranging from 1 x 10(8) to 2 x 10(9) cfu/g tumor. The amount of VNP20009 accumulated in the liver ranged from 3 x 10(4) to 2 x 10(6) cfu/g. The distribution of Salmonella in tumors was homogenous; YS7212 could be detected from the periphery to the interior portion of the tumors. Using mice with various immunodeficiencies, we also discovered the same preferential accumulation of Salmonella in tumors implanted in these mice. The use of Salmonella as a protein delivery vector was shown by IV administration of the bacteria expressing either green fluorescent protein (GFP) or cytosine deaminase (CD) into tumor-bearing mice. GFP and CD were detected in tumors, but not in livers, taken from mice inoculated with Salmonella carrying these genes. Bacteria accumulation and CD expression persisted in the tumors for up to 14 days after a single bolus IV administration of bacteria to tumor-bearing mice.

Animals↗

Primary antiphospholipid syndrome manifested as venous stasis retinopathy.

Primary antiphospholipid syndrome is a condition in which antiphospholipid antibodies may be present without any associated medical disorder. Thrombosis is the hallmark of this syndrome. We report the case of a 22-year-old female with the chief complaint of floating spots in the right eye for two months. No underlying connective tissue disease or systemic disease was noted. Ophthalmic examination revealed retinal hemorrhage, retinal vein engorgement and optic disk swelling in the right eye only, and normal visual acuity in both eyes. Retinal fluorescein angiography showed venous stasis and branch vein leakage in the right eye. An antibody profile revealed the presence of immunoglobulin G anticardiolipin antibodies, which confirmed the diagnosis of primary antiphospholipid syndrome.

Adult↗

[Changes of glucocorticoid receptor in cerebral and hepatic cytosol during decompression stress injury in rats].

Objective. To observe the changes of glucocorticoid receptor (GR) in cerebral and hepatic cytosol during decompression stress injury in rats. Method. 30 rats were divided into 5 group. They were placed into the compression chamber for compression and decompression. The binding capacity of GR of cerebral and hepatic cytosol were measured by the exchange assay, using 3H dexamethasone as the ligand. Meanwhile, decompression bubbles on pericardial area were measured using Doppler ultrasonic method. Result. The binding capacity of GR of cerebral and hepatic cytosol reduced after decompression stress injury in the animals, especially cerebral cytosol (P<0.01, P<0.05). The result also showed that the binding capacity of cerebral and hepatic GR should have further decreased, if the therapeutic measure had not been used in animals suffered from decompression sickness (DCS). Conclusion. The changes of the binding capacity of GR of cerebral and hepatic cytosol were proved to be related to decompression stress injury, which might be taken as one of the indices for evaluating injury degree of DCS.

Animals↗

In vivo analysis of cancerous gene expression by RNA-polymerase chain reaction.

An easy and routine procedure to amplify messenger RNA (mRNA) libraries from a few tissue cells can provide molecular gene expression profiles at high resolution. A novel PCR-like method, the RNA-PCR, was developed to generate high quality and quantity mRNAs from as few as 20 cells (2 pg mRNAs). The principle relies upon the cycling steps of promoter-linked double-stranded cDNA synthesis and promoter-driven transcription to amplify mRNAs up to 250-fold/cycle with good representation of high and low copy mRNAs. The amplified mRNA libraries were shown to possess high fidelity, purity, specificity and reproducibility for in vivo analyses of cancerous gene expression in human prostate cancers.

Base Sequence↗

Lipid A mutant Salmonella with suppressed virulence and TNFalpha induction retain tumor-targeting in vivo.

Systemically administered tumor-targeted Salmonella has been developed as an anticancer agent, although its use could be limited by the potential induction of tumor necrosis factor alpha (TNFalpha)-mediated septic shock stimulated by lipid A. Genetic modifications of tumor-targeting Salmonella that alter lipid A and increase safety must, however, retain the useful properties of this bacteria. We report here that disruption of the Salmonella msbB gene reduces TNFalpha induction and increases the LD50 of this pathogenic bacteria by 10,000-fold. Notwithstanding this enormous difference, Salmonella retains its tumor-targeting properties, exhibiting tumor accumulation ratios in excess of 1000:1 compared with normal tissues. Administration of this bacteria to mice bearing melanoma results in tumors that are less than 6% the size of tumors in untreated controls at day 18. Thus, the antitumor activity previously demonstrated using tumor-targeting Salmonella with normal lipid A is retained. Lipid modification of tumor-specific bacterial vectors provides a means for reducing septic shock and further suggests that the antitumor activity of these bacteria may be independent of TNFalpha.

Acyltransferases↗

Evaluation of high-performance anion-exchange chromatography with pulsed electrochemical and fluorometric detection for extensive application to the analysisof homologous series of oligo- and polysialic acids in bioactive molecules.

Our previous studies have shown extensively diverse structures in oligo/polymers of sialic acid (oligo/polySia) that are expressed often in developmentally regulated manner on animal glycoconjugates. The aim of this study was to establish highlysensitive and specific methods that can be used to identify diverse types of oligo/polySia and thus can be applied to studies of biological phenomena associated with the differential expression of oligo/polySia chains with different degree of polymerization (DP). As model compounds, we analyzed five different homologous series of oligo/polySia, (-->8Neu5Acalpha2-->)(n), (-->9Neu 5Acalpha2-->)(n), (-->8Neu5Gcalpha2-->)(n), (-->5-O(glycolyl)-Neu5Gcalpha2-->)(n), and Neu5Gc9SO(4)alpha2-->(-->5-O(glycolyl)-Neu5Gcalpha2--> )(n), ()expressed in various biopolymers. The latter two structures have recently been identified in sea urchin egg receptor for sperm. First we examined application of high-performance anion-exchange chromatography (HPAEC) on a CarboPac PA-100 column with pulsed electrochemical detection (PED) to new types of oligo/polySiacompounds and confirmed that resolution of high polymers (DP >70) of sialic acids was remarkable as reported previously. However, there are limitations in sensitivity and selectivity in PED that become significant when material is available only in a minute amount or material contained a large proportion of protein. These limitations can be circumvented by fluorometric detection of oligo/polySia tagged with 1,2-diamino-4, 5-methyl-enedioxybenzene (DMB) at the reducing terminal residues after separation on a MonoQ HR5/5 column. The latter method can be applied to any type of oligo/polySia we examined if we choose the derivatization conditions and is more sensitive and specific than the method with PED for analysis of oligo/polySia with DP up to 25.

Animals↗

A left atrial thrombus is not an absolute limitation to balloon mitral commissurotomy for patients with mitral stenosis. a serial transesophageal echocardiographic study.

Previous reports did not encourage balloon mitral commissurotomy (BMC) when left atrial (LA) thrombi were located beyond LA appendage. We hypothesize that LA thrombi may be resolved in some patients after anticoagulant therapy, and BMC can be performed subsequently. In the present study, we used transesophageal echocardiography (TEE) to evaluate the effects of anticoagulant on LA thrombi in patients with mitral stenosis, to compare the clinical differences between patients with (group A) and without (group B) resolution of LA thrombi, and to evaluate the safety of subsequent BMC in these patients. TEE was performed on 190 consecutive patients with mitral stenosis; 14 (7.4%) of them were found with LA thrombi. Serial TEE was performed and optimal anticoagulant therapy was achieved in all 14 patients. The thrombi were located within the LA appendage in 6 cases, attached to the LA posterior wall in 5, posterior wall and interatrial septum in 1, and LA appendage and posterior wall in 2. Based on the 6-month TEE follow-up, we found that the LA thrombi disappeared in 8 (57.2%) patients (group A) and persisted in 6 patients (group B). LA thrombi resolved within 3 months in 7 group A patients (87.5%). Furthermore, the resolution of LA thrombi was more frequently observed in patients either with a smaller LA dimension (51.9 +/- 3.4 vs. 57.8 +/- 4.8 mm, p = 0.02) or with their thrombi located inside their LA appendage (p = 0.03). No differences in other clinical and echocardiographic variables were noted between these two groups. Subsequently, group A patients underwent BMC without complications of systemic embolization. In conclusion, LA thrombi can be resolved after optimal anticoagulant therapy in a considerable proportion of patients with mitral stenosis. Serial TEE studies are helpful to observe LA thrombus resolution; they may also be useful in planning the treatment strategy.

Adult↗

Optimal control of blood pressure can reverse left ventricular hypertrophy in uremic hypertensive hemodialysis patients.

We investigated the effects of antihypertensive treatment on left ventricular hypertrophy (LVH) of long-term hemodialysis patients. In uremic patients, it is still controversial in antihypertensive effect to the regression of LVH. The left ventricular size and function of 39 uremic hypertensive long-term hemodialysis patients (27 men, 12 women, mean age 58.3) was evaluated with M-mode, 2-dimensional and Doppler echocardiography before, and 12 months after, the start of combined antihypertensive therapy. This therapy included angiotensin II converting enzyme inhibitors, beta-blockers and calcium antagonists. Patients were classified as responders or nonresponders, depending upon whether their systolic blood pressure (SBP) decreased by more than 10 mmHg after antihypertensive treatment for 12 months. Before treatment, 36 (92%) patients had LVH and diastolic dysfunction and three (8%) had systolic dysfunction. At the end of 12 months, only 25 (64%) patients had LVH, 30 (77%) had diastolic dysfunction and 2 (5%) had systolic dysfunction. Left ventricular mass index (LVMI) also decreased from 203.63 +/- 70.47 g/m2 to 178.57 +/- 67.31 g/m2. LVMI correlated with systolic blood pressure (SBP) but did not correlate with diastolic blood pressure (DBP). There were 26 responders and 13 non-responders. Among responders, both the SBP (153.91 +/- 13.24 mmHg vs 134.43 +/- 14.21 mmHg, p < 0.01) and DBP (90.39 +/- 7.89 mmHg vs 79.98 +/- 7.35 mmHg, p < 0.01) decreased significantly after antihypertensive therapy. Responders also exhibited progressive regression of LVH (LVMI decreased significantly from 208.52 +/- 72.03 g/m2 to 168.52 +/- 55.53 g/m2, p < 0.05). However, LVH regression was not found in nonresponders (LVMI showed 194.84 +/- 64.36 g/m2 vs 193.66 +/- 77.67 g/m2). We conclude that good control of blood pressure can reverse LVH in hypertensive hemodialysis patients.

Adult↗

Circadian and weekly variations in pain onset of acute myocardial infarction.

BACKGROUND: A seasonal variation with more myocardial infarctions in the winter months due to cold weather has been reported. Other reports have described excess numbers of acute myocardial infarction (AMI) in the summer in Southern USA due to hot temperatures. To determine whether circadian and seasonal variations affect the incidence of AMI in the subtropical area of Taiwan, 480 consecutive patients with AMI admitted to our coronary care units were analyzed. METHODS: Six-hourly intervals over 24 hours (4 periods), daily intervals in a week (7 days) and monthly intervals in a year (12 months) were respectively studied. The distributions of the numbers of AMI occurring in the six-hour intervals were tested for differences among the four periods using the chi-squared test for goodness of fit. RESULTS: We found that there was a circadian variation in the onset of AMI with a morning peak (6 am to noon) (35%, chi 2 = 28.52, df = 3, p < 0.01) but no secondary late evening peak. The incidence of AMI was significantly lower on Sundays (9%) than on the other weekdays (chi 2 = 16.37, df = 6, p = 0.012). However, no seasonal variation (no winter or summer peaks) occurred in the incidence of AMI in this study (chi 2 = 0.77, df = 3, p = 0.99). CONCLUSION: Our results showed that there was a predominant morning peak in the onset of AMI. The low incidence of AMI cases on Sunday compared with other weekdays suggested that relief from tension or workload on Sundays might have an important role in this low percentage of AMI. Differing from other reports, there was no seasonal variation in the occurrence of AMI in our study, suggesting that the warm climate of a subtropical region does not provide an environment that is likely to increase the frequency of AMI.

Adult↗

Congenital hepatic arterioportal fistula complicated with gastrointestinal bleeding treated with transcatheter embolization: case report.

Congenital hepatic arterioportal fistula (HAVF) is extremely rare in children. We present a patient with congenital hepaticoportal arteriovenous fistula complicated with gastrointestinal bleeding treated using transcatheter arterial embolization. Our patient was the youngest (2 days old) case ever reported with congenital HAVF and the first one to receive arterial embolization for HAVF during childhood. The 3-year-old girl was suggested of having congenital HAVF using Doppler ultrasonography. However, her family refused further investigation, and she was lost to follow-up. Three years later, she was sent to our hospital due to melaena. Repeated ultrasonography revealed dilated intrahepatic portal vein with arterial flow demonstrated using Doppler imaging. No esophageal varices or gastric or duodenal ulcer was seen during endoscopy. Angiography showed a HAVF and transcatheter embolization was done simultaneously. Follow-up at one and two weeks post-embolization revealed no more shunt flow within the portal vein, though cystic like dilatation of the portal vein persisted, and no thrombosis was observed. This case emphasizes that transcatheter arterial embolization can be easily and successfully used for treating childhood congenital HAVF. Abnormal dilatation of the portal vein in children needs doppler evaluation and possibly angiography.

Arteriovenous Fistula↗

Intussusception in a child infected with enterovirus: case report.

Most intussusceptions in childhood are idiopathic. The association of viral infection has been suspected for decades. We report a case of ileocolonic intussusception in a child during a course of enterovirus infection. A 20-month-old girl with vomiting and irritable crying of 4 days' duration was found to have intussusception by sonography. She had suffered from herpangina one week earlier. Due to her peritoneal signs, she underwent surgical manual reduction. A cluster of enlarged lymph nodes in the intussuscipiens was noted preoperatively by high resolution ultrasound. Two swollen lymph nodes were removed for pathologic evaluation and examined for a viral genome by polymerase chain reaction (PCR) amplification. Panenterovirus base pairs were confirmed on the electrophoresis print. During postoperative sonographic follow-up, significant shrinkage of previous mesenteric lymphoid hyperplasia was observed. In this article, we present the first case of childhood intussusception in associated with enterovirus infection, in which the panenterovirus genome was identified in the patient's mesenteric lymph nodes. This was also the first evaluation of the role of mesenteric lymph nodes in intussusception by high resolution sonography.

Enterovirus Infections↗

Multiplane transesophageal echocardiography for assessing cardiac abnormalities: comparison to biplane imaging.

BACKGROUND: Transesophageal echocardiography (TEE) is useful for visualizing the spatial relationships of the cardiac anatomy. The purpose of this study was to compare the diagnostic yield of multiplane TEE with that of biplane TEE in assessing cardiac abnormalities. METHODS: A total of 102 consecutive patients underwent an initial comprehensive diagnostic assessment using transverse (0 degree) and longitudinal (90 degrees +/- 2 degrees) planes in the biplane imaging technique. "Off-axis" tomographic sections through the full 0 degree to 180 degrees angle were obtained later by means of the gradual electrical rotation of the transducer. The echoscope can be manipulated to improve the quality of images. All data were recorded on high fidelity videotapes. Subsequently, one observer reviewed only biplane TEE images, while another reviewed only multiplane TEE images; both were blinded to the other's TEE data. The echocardiographic results obtained by these two observers were compared to determine whether multiplane TEE provides any additional information. RESULTS: Multiplane TEE detected more cardiac lesions (275) compared to biplane TEE (235). Significantly more (70 cases) information affecting patient management was obtained using multiplane TEE. Among these patients, biplane TEE detected cardiac lesions in 48 (68.6%) patients. Additional diagnoses provided by multiplane TEE were found in 22 (31.4%) patients. These findings included ventricular septal defect in two patients, prosthetic valve dysfunction in three, cardiac tumor or clot in four, endocarditis in two, aortic dissection in one, valvular abnormality in nine and coronary arteriovenous fistula in one. CONCLUSIONS: Multiplane TEE provides precise visualization of cardiac structures without undue probe manipulation, resulting in greater diagnostic assurance than does biplane TEE.

Adolescent↗

[Changes and its measurement of intracellular Ca2+ during exposure to hyperbaric oxygen].

Objective. To investigate the rule of change of intracellular Ca2+ and its measurement method during exposure to hyperbaric oxygen (HBO). Method. Microfluorescence method was used to measure the changes of intracellular Ca2+ concentration in co-cultured endothelial cells (EC) and smooth muscle cells (SMC) in a specially designed miniature oxygen chamber. Result. (1) [Ca2+]i changes during HBO exposure can be clearly observed directly in the chamber. (2) Within 5 min during 0.2 MPa and 0.3 MPa HBO exposure, EC[Ca2+]i and SMC[Ca2+]i showed a tendency, to increase at first and then decrease with time throughout the exposures, especially the SMC[Ca2+]i. The EC ruptured under exposure to 0.4 MPa HBO. Conclusion. During HBO exposure, EC[Ca2+]i and SMC[Ca2+]i showed biphasic changes, which increased at first and then decreased. The technique and method used were reliable and suitable for investigating of intracellular [Ca2+]i changes under HBO.

Animals↗