Troponin I and autotransfusion of shed mediastinal blood in redo cardiac operation.
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Blood Transfusion, Autologous↗
Biomedical subjects
L W Chen
Publications and source records attributed to L W Chen.
Changes in gut mucosal nitric oxide synthase (NOS) activity after thermal injury and its relation with barrier failure.
This study was designed to investigate changes in mucosal NOS activity after burns and its relation to barrier failure. In Experiment 1, female specific pathogen free (SPF) Sprague-Dawley rats underwent 35% total body surface area (TBSA) burn. One to six days after burn, intestinal permeability was determined from the plasma leakage of fluorescein isothiocyanate (FITC)-dextran 4400, intestinal mucosal cNOS and iNOS activity were assayed using Griess' reagent, and the cellular localization of iNOS was examined using immunostaining. In Experiment 2, S-methylisothiourea (SMT) was given (5 mg/kg, i.p. every 12 h) for 2 days to suppress inducible NOS (iNOS) activity after thermal injury. On postburn Day 2, the effect of SMT on gut mucosal NOS activity, intestinal permeability, and barrier function were evaluated. The activity of iNOS increased 24 h after the injury and up to a maximum of twofold on postburn Day 2, and decreased thereafter. The increase in iNOS activity in gut mucosa correlated well with the increase in intestinal permeability, an index for barrier failure (r = .776, p = .0002). Results from iNOS immunostaining showed that changes in mucosal iNOS activity after the burn occurred mainly in the enterocytes rather than in the macrophages. Administration of SMT decreased mucosal iNOS activity, intestinal permeability, and bacterial translocation incidence to mesenteric lymph node concurrently. In conclusion, thermal injury induces intestinal mucosal iNOS, which is principally in the enterocytes. The increased intestinal iNOS activity was closely related to barrier failure. SMT inhibited intestinal mucosal iNOS activity and prevented barrier failure as demonstrated by a decrease in BT occurrence and intestinal permeability.
Animals↗
Chronic activation of neurokinin-1 receptor induces pulmonary hypertension in rats.
In this study we explored the hypothesis that chronic activation of neurokinin-1 (NK-1) receptor induces pulmonary hypertension in Wistar rats. First, the activation of NK-1 receptor on the pulmonary circulation was investigated by use of a chronic injection of NK-1 agonist [Ser9,Met(O2)11]-substance P (1 x 10(-9) mol/kg) for 2 wk at sea level (rats breathed room air) and during hypoxia (rats were placed in a hypobaric 380-Torr chamber). Second, we studied the effect of NK-1 antagonist (CP-96345) on developing and developed (after 4 wk of chronic hypoxia) pulmonary hypertension. Pulmonary arterial pressure, the weight ratio of right ventricle to left ventricle + septum, hematocrit, and substance P (SP) were measured. We found that NK-1 agonist significantly increased pulmonary arterial pressure in the sea-level but not in the hypoxic group. However, NK-1 agonist induced neither right heart hypertrophy nor polycythemia. CP-96345 significantly decreased pulmonary arterial pressure in the hypoxic group but had no effect in the sea-level group. Furthermore, CP-96345 significantly attenuated the acute SP-induced increase in pulmonary arterial pressure in the sea-level and hypoxic groups, with a larger increase in the hypoxic group. These results suggest that chronic activation of NK-1 receptor induces pulmonary hypertension and that there is an increase in the sensitivity of pulmonary vessels in response to SP in chronically hypoxic rats.
Animals↗
Red light suppresses N-acetylserotonin but does not elevate 5-HT and 5-HIAA of the rat pineal glands at night.
HPLC with EC detector was used to study the red light effect on the rhythmicity of catecholamines (NE, DOPAC and dopamine) and indoleamines (NAS, 5-HT, 5-HIAA) in the pineal glands and retinas of the Sprague-Dawley rat. We found the prominent nocturnal elevations of NAS in rat pineal glands and the suppression of the NAS but not the elevation of 5-HT and 5-HIAA after red light exposure at night. Our data show two findings: metabolic pathway of the indoleamines (5-HT, 5-HIAA and NAS) after red light exposure at night may be different from those by white light. Second, the increased HIOMT activity that effects on 5-HT and 5-HIAA may also be involved in the indoleamine formation after red light exposure at night.
Animals↗
[Percutaneous transvenous biopsy for the diagnosis of a right atrial myxoma].
Intracardiac tumors are generally diagnosed by transthoracic echocardiography, transesophageal echocardiography and, more recently, magnetic resonance imaging. However, these techniques do not permit a histopathologic diagnosis. When surgery is not indicated because of limited hemodynamic changes but the benign nature of the tumoral mass is questionable, percutaneous transvenous biopsy, when technically feasible, may represent an alternative approach. In this case report, we utilized percutaneous transvenous biopsy to obtain specimens from a right atrial mass in a 39-year-old woman.
Adult↗
Mid-term results of conventional bypass surgery for complex proximal left anterior descending coronary artery stenoses.
BACKGROUND: The significant involvement of proximal left anterior descending (LAD) coronary artery affects patient prognosis and must be treated. Recently, as alternative methods to conventional coronary bypass (CABG), minimally invasive direct coronary artery bypass grafting (MIDCAB) and percutaneous transluminal coronary angioplasty with stent implantation (PTCA/S) have been proposed to reduce costs and patient discomfort. The aim of this study was to obtain early and medium-term results of CABG in patients with complex LAD disease in whom the expected results with PTCA/S or MIDCAB would have been suboptimal. METHODS: We retrospectively examined one hundred consecutive patients subjected to isolated CABG who received either a single graft to LAD or several grafts to LAD and diagonal branches. The choice of CABG was due to poor expectable results with PTCA/S or MIDCAB because of anatomical characteristics of the lesion, inclusion in ongoing randomized study comparing surgical versus non-surgical revascularization, or preference on the part of the cardiologist or patient. RESULTS: Left internal mammary artery (LIMA) was grafted to LAD in 99 (99%) patients; 65 (65%) patients received at least one saphenous graft to the diagonal branches. No death was observed within 30 days from the operation. One (1%) patient had a perioperative non-Q myocardial infarction (MI). At a mean follow-up time of 38 +/- 16 months (range 2-60), there were no cardiac deaths and no new MI. Six patients complained of recurrent angina: in all cases but one (vein graft failure to a diagonal branch), there were no clinical or diagnostic signs suggesting other graft failures. The probability of freedom from early and late events, including cardiac death, MI and recurrence of angina regardless of site, was 99% at 1 year and 86% at 5 years. CONCLUSIONS: At present, conventional CABG seems to be the "gold standard palliation" of LAD disease in most cases. It can be performed safely with excellent early and medium-term results in terms of freedom from cardiac events. Its comparison with percutaneous transluminal techniques and MIDCAB needs to be addressed in further prospective studies.
Adult↗
Use of a diffusion model for assessing the performance of poly(vinyl alcohol) bioartificial pancreases.
Islets of Langerhans surrounded by a semipermeable membrane to prevent an immune response by the host immunosystem is a potential way of treating type I diabetes mellitus. In this study, poly(vinyl alcohol) (PVA) tubular membranes with added polyethylene glycol to create pores in the skin layer were prepared to improve their diffusion property. In a static incubation study, islets cultured in the PVA tubular membranes still demonstrated their function of secreting insulin after 30 days. When the tubular PVA bioartificial pancreas was perifused in a small chamber with RPMI-1640 medium containing glucose at concentrations of 5.6-16.6 mmol/L, insulin release began to increase without delay. Therefore, such a membrane is an alternative potential material for a bioartificial pancreas. In addition, a mathematical mass transfer model of insulin release was developed and compared with the perifusion data. It was shown that satisfactory kinetics could be achieved with a PVA membrane. However, the model showed that the insulin output of islets cultured in the PVA tubular membrane must be increased to improve the performance significantly. These findings suggest that a bioartificial pancreas using a PVA membrane is a promising material, but the technique for seeding islets in the chamber requires further modification.
Animals↗
Comparison of epoxides on grafting collagen to polyurethane and their effects on cellular growth.
The current study investigated the effects of vary epoxides on linking capacity of collagen to carboxyl-group-enriched polyurethane (PU) and the consequent effects on the growth of endothelial cells. Epoxides of EX-810, 1,4BDE, DER732, DER331, and DER332 were initially reacted with the carboxyl groups of PU substrates at 110 degrees C for 20 h. Free epoxy rings of epoxide-PU substrates, characterized by Fourier transform infrared spectroscopy and quantified by titration with HCl and NaOH, were available for collagen grafting. The amounts of collagen grafted were in accordance with the amounts of free epoxy rings detected and correlated with the growth of endothelial cells on the substrates. Our results indicated that epoxides with shorter aliphatic intermediate chain can graft more collagen to the epoxide-PU substrates than epoxides with longer intermediate chain or with aromatic groups. Epoxides were also demonstrated to be nontoxic linking agents for biomaterials.
Cell Division↗
Mesencephalic dopaminergic neurons expressing neuromedin K receptor (NK3): a double immunocytochemical study in the rat.
By using a double immunocytochemical method we examined the distribution of dopaminergic neurons expressing neuromedin K receptor (NKR; NK3) in the rat brain. The distribution of NKR-like immunoreactive (-LI) neurons completely overlapped that of tyrosine hydroxylase (TH)-LI neurons in the retrorubral field (A8), substantia nigra (A9), ventral tegmental area and nucleus raphe linealis (A10). Completely or partially overlapping distributions of NKR- and TH-LI neurons were found in certain regions of the hypothalamus (A11-A15) and olfactory bulb (A16). Neurons showing both NKR- and TH-like immunoreactivities, however, were only found in A8-A10: All of the NKR-LI neurons displayed TH-like immunoreactivity, and about 71-86% of the TH-LI neurons expressed NKR-like immunoreactivity. The present results provided morphological evidence for physiological modulation of dopaminergic neurons by tachykinins through NKR in A8-A10.
Animals↗
Specific inhibition of iNOS decreases the intestinal mucosal peroxynitrite level and improves the barrier function after thermal injury.
Failure of GI tract mucosa to act as a barrier against bacterial translocation (BT) has been proposed as a potential source of sepsis and subsequent multiple organ failure post thermal injury. Nitric oxide (NO) is an inorganic radical produced by NO synthase (NOS) from L-arginine. Gut mucosal constitutive NOS (cNOS) provides protection for itself. In contrast to cNOS, inducible NOS (iNOS) releases far greater amounts of NO, promotes oxidative reactions and is responsible for tissue injury. Peroxynitrite formed by the rapid reaction between superoxide and NO, is a toxic substance that contributes to tissue injury in a number of biological systems. This study was designed to investigate the effect of iNOS specific inhibitor S-methylisothiourea (SMT) on the postburn intestinal mucosal barrier function and the possible mechanism of SMT's action. Female SPF Sprague Dawley rats underwent 35% total body surface area (TBSA) or sham burn. Either SMT or the same volume of saline was given (5 mg/kg, i.p. q 12 h) for 2 days to assess the effect of iNOS inhibition. On postburn day 2, the intestinal mucosal cNOS and iNOS activity were assayed by using Griess' reagent, the mesenteric lymph node (MLN), spleen and liver were collected and cultured for BT assay and the cellular localization of nitrotyrosine, a marker for peroxynitrite activity, was examined by immunostaining. After thermal injury in rats, administration of SMT for 2 days decreased the intestinal mucosal iNOS activity/ tNOS activity ratio and the BT incidence. Nitrotyrosine immunostaining of the intestinal mucosa showed a decrease in the SMT-treated group. These findings suggest that SMT, a specific inhibitor for iNOS improves the barrier function after burn by suppression of the intestinal mucosal iNOS activity. The decrease in NO production resulted in decreased formation of peroxynitrite and subsequently decreased damage of mucosal tissue.
Animals↗
A new reverse-based free flap: reverse saphenous free flap.
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Arteries↗
Use of health services by Chinese elderly in Beijing.
OBJECTIVES: This article provides an inquiry into use of health services by the elderly. METHODS: The authors operationalize models of use with a survey of 350 elderly Chinese. Because the survey involves native Chinese, the empirical test can isolate functional social support as well as "structural" social supports (marriage, living with children). RESULTS: The principal findings comport with prior work: the strongest determinants of the use of health services by the elderly are those that relate to need. In addition, structural social support impacts use but demonstrates complex patterns. CONCLUSIONS: The availability of family support increases physician visits while diminishing the probability of a hospital stay. Increased Western physician use ties to increased use of Chinese physicians and increased hospitalization. Functional social support plays a role as well. Finally, income effects did not play a large role in determining the use of health services among this population.
Activities of Daily Living↗
Loss of expression of the p16 gene is frequent in malignant skin tumors.
Expression of the p16 gene from 30 malignant skin tumors has been surveyed by immunohistochemical assay. Gene point mutations were detected by DNA direct sequencing and the mRNA level of gene expression was measured by RT-PCR. A silent point mutation of the p16 gene was found in only one patient. However, loss of expression of the p16 gene was noticed in 23 of 29 samples (79.3%). Correlation between loss of expression of the p16 gene and metastasis is significant (p = 0.0036). These findings suggest that loss of expression of the p16 gene may play a critical role in tumor progression of malignant skin tumors.
Adenocarcinoma↗
Renal function of substance P in rats chronically exposed to hypoxia.
BACKGROUND: We studied the renal action of substance P (SP) in rats chronically exposed to hypoxia (high altitude, HA), compared to control rats kept at sea level (SL). METHODS: Hypoxia was induced by placing female Wistar rats (182-225 g) in an altitude chamber (5500 m) 15 h.d-1 for 4 weeks. RESULTS: Intrarenal arterial infusion of substance P (60 ng.kg-1. h-1) increased the excretion of urine, sodium in both groups of rats, however, the excretion of kallikrein (KK) and the glomerular filtration rate (GFR) were not significantly altered. After aprotinin (10,000 kiu.kg-1. min-1) treatment, kallikrein was depleted, and substance P lost its diuretic action. Spantide, an SP antagonist (6000 ng.kg-1. h-1, I.V.) decreased urine, and urinary excretion of sodium and potassium in SL rats, but not in HA rats. Acute renal denervated diuresis in SL rats was not modified after Spantide administration. Finally, it was found that both SP and SP antagonist did not significantly change the renal parameters in either group of rats after chronic renal denervation. CONCLUSION: We made the following conclusions: a) endogenous renal action of SP was suggested in SL but not in HA rats; b) the renal action of SP might be through KK release, although urinary KK did not increase after SP administration; and c) SP action is renal nerve dependent in both groups of rats.
Altitude Sickness↗
Neurokinin B receptor (NK3)-positive neurons expressing c-fos after chemical noxious stimulation on the peritoneum: a double staining study in the nucleus tractus solitarius of the rat.
Neurokinin B receptor (NKR; NK3)-like immunoreactivity (LI) was densely distributed in the nucleus tractus solitarius (NST) of the rat. Approximately 32% of the neurons with NKR-LI in the NST expressed c-fos protein after chemical irritation on the peritoneum with acetic acid. The present results suggest that neurons containing NKR in the NST may be involved in the integration of noxious afferent information from the peritoneum in the rat.
Acetic Acid↗
Effect of forms of collagen linked to polyurethane on endothelial cell growth.
Collagen has been widely coated or grafted onto polymer surfaces to improve the biocompatibility of materials. To better support the growth of endothelial cells on polyurethane (PU), collagen was grafted to the carboxyl group enriched PU through 1,2-bis(2,3-epoxypropoxy)ethane linking. Our results demonstrated that collagen in various conditions may result in different forms being grafted to the PU substrate, which subsequently affected the growth of endothelial cells. Collagen predialyzed against physiological phosphate buffered saline (PBS) could be reconstituted into native type fibrils with a bigger diameter at 37 degrees C than could collagen neutralized by titration with NaOH. At low temperature, titrated collagen formed floss-like fibrils packed in a ball with cobblestone-like morphology. The amount of collagen grafted was related to the condition of the collagen used, which in consequence affected the diameter of the collagen fibril formed and the growth of endothelial cells. In conclusion, reconstituted collagen fibrils formed from collagen in PBS at 37 degrees C grafted in the highest amounts to an epoxy-PU substrate and that optimally supported the growth of endothelial cells. Such prepared materials may be potentially good vascular bioprosthetic materials and may provide a wide range of biological applications.
Animals↗
Evaluation of asymmetric poly(vinyl alcohol) membranes for use in artificial islets.
Islets of Langerhans surrounded by a semipermeable membrane to prevent the host immunosystem is a potential way to treat type I diabetes mellitus. In this study, a series of poly (vinyl alcohol) membranes were formed by adding polyethylene glycols to create pores in the skin layer. The permeability study showed the skin layer structure had an influence on the diffusion of low molecular weight glucose, vitamin B12 and insulin. The mass transfer coefficient was improved from 1.04 x 10(-4) to 2.16 x 10(-4) cm/ sec for glucose, from 2.84 x 10(-5) to 8.36 x 10(-5) cm/sec for vitamin B12 and from 1.45 x 10(-6) to 4.15 x 10(-6) cm/sec for insulin, whereas the passage of immunoglobulin G was completely prevented, indicating that these membranes could be effective in protecting islets from immunorejection. Thus such a membrane is an alternative potential material for artificial islets. In addition, we examined the insulin secretory response of islets separated by a poly(vinyl alcohol) membrane. We found that the insulin-secretion rate is relatively rapid compared to the permeation rate of insulin; thus, the process of the artificial islets is insulin-diffusion-controlled.
Biocompatible Materials↗
Renal kallikrein in chronic hypoxic rats.
1. We have studied the role of kallikrein (KK) in the maintenance of renal function in chronic hypoxic rats (high altitude; HA), compared with control rats kept at sea level (SL). Hypoxia was induced by placing female Wistar rats (198-290 g) in an altitude chamber (5500 m) 15 h/day for 4 weeks. Experiments were also conducted to study the interaction of KK with renal nerve activity and endothelin (ET), two parameters previously shown to be altered in this model. 2. It was found that renal cortex tissue KK activity (TKA) was not significantly different in 10 SL and 10 HA rats. However, the urinary KK activity (UKA) was reduced nearly to half (from 35.2 +/- 4.6 to 18.5 +/- 1.7 pkat/min) in HA rats after 4 weeks of chronic hypoxia. 3. Acute renal denervated diuresis was accompanied by a significant increase in UKA (from 9 +/- 2 to 14 +/- 2 pkat/min in HA and denervated HA rats, respectively; P < 0.05) in HA rats. Intrarenal arterial pretreatment of aprotinin reduced the denervated diuresis. 4. Endothelin (600 ng/kg per h) reduced urine flow, sodium and potassium excretion in the ipsilateral kidney in another 10 SL and 10 HA rats. The extent of the drop of these parameters was significantly less in HA rats. Urinary KK activity was correlated significantly with the measured renal functional parameters (r ranging from 0.472 to 0.612) in SL rats, but was insignificant in HA rats (r ranging from 0.032 to 0.192). 5. We have demonstrated that chronic exposure to hypoxia decreases urinary KK excretion and that KK is involved in acute renal denervated diuresis generated in these animals. The present study suggests that KK plays a partial role in the maintenance of renal function in chronic hypoxic rats.
Analysis of Variance↗