Catecholamines and transplantation.
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Brain Death↗
Biomedical subjects
C Wei
Publications and source records attributed to C Wei.
Expression of fas ligand on bile ductule epithelium in biliary atresia--a poor prognostic factor.
PURPOSE: The aim of this study was to investigate the possible role of Fas and Fas ligand system in biliary atresia. METHODS: Immunohistochemical stains of Fas and Fas ligand (FasL) and in situ hybridization of Fas ligand messenger RNA (mRNA) were performed on paraffin-embedded liver specimens of 36 biliary atresia, 6 choledochal cysts, and 14 nontumorous parts of pediatric liver tumors. Apoptosis was detected by terminal deoxynucleotidyl transferase deoxy-UTP nick end labeling (TUNEL). The grade of liver fibrosis and results of bile drainage on the patients with biliary atresia were compared with the results of FasL expression. RESULTS: Fas protein was positive on the hepatocytes and bile ductule epithelia of all the livers examined and also positive on some monocytes around the portal area in all the biliary atresia patients. FasL protein was positive on bile ductule epithelia in 10 biliary atresia patients and also positive on some monocytes in most of the biliary atresia patients. Positive signals of FasL mRNA were noted on hepatocytes in 4 biliary atresia, bile ductule epithelia in 19 biliary atresia patients, and some monocytes in most of the biliary atresia patients. Apoptotic nuclei were present among monocytes in all the biliary atresia livers but present among bile ductule epithelia only on the BA with positive FasL mRNA signals on ductule epithelium. The fibrosis grade was similar between biliary atresia with positive FasL mRNA signals and negative signals. The bile drainage was better in the biliary atresia without positive FasL mRNA signals. CONCLUSIONS: Fas ligand expression on bile ductule epithelia in biliary atresia may be induced to counterattack the infiltrating lymphocytes. Although the factors for post-Kasai bile drainage are multiple, the authors suggest Fas ligand expression on bile ductule epithelia may be a poor prognostic factor by playing a role in the continuous damage and obliteration of intrahepatic bile ducts after Kasai operation.
Base Sequence↗
The transmission of gas pressure to xylem fluid pressure when plants are inside a pressure bomb.
In earlier work tobacco leaves were placed in a Scholander-Hammel pressure bomb and the end of the petiole sealed with a pressure transducer in order to measure pressure transmission from the compressed gas (Pg) in the bomb to the xylem fluid (Px). Pressure bomb theory would predict a 1:1 relationship for Pg:Px when tobacco leaves start at a balance pressure of zero. Failure to observe the expected 1:1 relationship has cast doubt on the pressure-bomb technique in the measurement of the xylem pressure of plants. The experimental and theoretical relationship between Px and Pg was investigated in Tsuga canadensis (L) branches and Nicotiana rustica (L) leaves in this paper. It is concluded that the non 1:1 outcome was due to the compression of air bubbles in embolized xylem vessels, evaporation of water from the tissue, and the expansion of the sealed stem segment (or petiole) protruding beyond the seal of the pressure bomb. The expected 1:1 relationship could be obtained when xylem embolism was eliminated and stem expansion prevented. It is argued that the non 1:1 relationship in the positive pressure range does not invalidate the Scholander pressure bomb method of measuring xylem pressure in plants because Px never reaches positive values during the determination of the balance pressure.
Plant Proteins↗
Ground state of a dipolar crystal
We provide some of the strongest evidence to date that the ground state structure of an infinite collection of point dipoles with hardcore sphere interactions is body-centered tetragonal. The structure with the next highest binding energy is not face-centered cubic; a particular honeycomb structure has lower energy.
Journal Article↗
Assembly of double-shelled, virus-like particles in transgenic rice plants expressing two major structural proteins of rice dwarf virus.
Rice dwarf virus (RDV) is a double-shelled particle that contains a major capsid protein (P8), a major core protein (P3), several minor core proteins, and viral genomic double-stranded RNA. Coexpression of P8 and P3 in transgenic rice plants resulted in formation of double-shelled, virus-like particles (VLPs) similar to the authentic RDV particles. The VLPs were not detected in transgenic rice plant cells expressing P8 alone. This in vivo result suggests that P8 interacted with P3 and that these two proteins provide the structural integrity required for the formation of VLPs in rice cells independently of other structural proteins, nonstructural proteins, or viral genomic double-stranded RNAs.
Capsid↗
Inhibition by calcium antagonism of circulating and renal endothelin in experimental congestive heart failure.
Endothelin (ET) is a potent vasoconstrictor and sodium-regulating peptide whose tissue and plasma concentrations are increased in congestive heart failure (CHF). ET may mediate its vasoconstrictor and sodium-regulatory actions secondary to an increase in intracellular calcium. Calcium influx may augment ET synthesis. Although felodipine, a dihydropyridine calcium-channel antagonist, is effective in reducing vascular resistance in generalized vasoconstriction, its actions in CHF on circulating and local tissue ET remain undefined. The current studies were designed to determine the modulating actions of felodipine (oral, 40 mg/day for 7 days; n = 6) in an experimental canine model of CHF produced by chronic thoracic inferior vena caval constriction (TIVCC) compared with normal (n = 7) and TIVCC-alone (n = 7) dogs. We hypothesized that felodipine would decrease circulating and renal ET. Plasma ET was significantly increased in TIVCC compared with normal dogs (26 +/- 0. 5 vs. 12 +/- 0.7 pg/ml, P < 0.05) and was markedly decreased by felodipine compared with TIVCC alone (14 +/- 3 vs. 26 +/- 0.5 pg/ml, P < 0.05). Renal ET immunohistochemical staining demonstrated the presence of ET in normal kidney, which was markedly increased in renal cortex and medulla in TIVCC dogs. Renal cortical and medullary ET staining densities were markedly decreased with felodipine compared with those with TIVCC alone. In the TIVCC + felodipine group, cardiovascular hemodynamics also was markedly improved compared with the TIVCC-alone group [systemic vascular resistance: 27 +/- 2 vs. 44 +/- 3 resistance units (RU), P < 0.05; pulmonary vascular resistance: 3.3 +/- 0.1 vs. 5.7 +/- 0.4 RU, P < 0.05; cardiac output: 2.9 +/- 0.2 vs. 1.7 +/- 0.1 l/min, P < 0.05]. This study demonstrates important modulating inhibitory actions of felodipine on renal and plasma ET in an experimental model of CHF.
Animals↗
The effect of angiotensin II on mitogen-activated protein kinase in human cardiomyocytes.
The role of angiotensin II (Ang II)-receptors on mitogen-activated protein kinase (MAPK) activation in cardiomyocytes remains controversial. Therefore, the current study was designed to investigate the actions of AT(1)- and AT(2)-receptors on Ang II-induced extracellular signal-regulated kinase (ERK), p38 and the c-Jun N-terminal kinase (JNK) MAPK activities in human cardiomyocytes. Human cardiac tissue was obtained from open-heart surgery (n=6). The cardiac tissue was minced and incubated in the special tissue culture system for 24 hours in the absence or presence of Ang II (10(-7) M). These studies were repeated with the AT(1)-receptor antagonist losartan (10(-6) M) or the AT(2)-receptor antagonist PD-123319 (10(-6) M). Immunohistochemical staining and Western blot analysis with phospho-antibodies were performed to determine ERK, JNK and p38 activities. Ang II increased ERK and p38 activities in human cardiomyocytes. The effects of Ang II were abolished by losartan and enhanced by PD-123319. Co-incubation with both losartan and PD-123319 resulted in a decrease of ERK and p38 activities in cardiomyocytes. The immunohistochemical staining of JNK showed no significant differences between Ang II alone, Ang II plus losartan and Ang II plus PD-123319 groups. In conclusion, Ang II has a potent effect on ERK and p38 MAPK activities in cardiomyocytes, by acting through AT(1)-receptors. This effect of Ang II is modified by AT(2)-receptors. Therefore, Ang II, via AT(1)- and AT(2)-receptor stimulation, has a distinct effect on MAPK activity in cardiomyocytes.
Aged↗
[Ultrastructure study of hepatocellular carcinoma treated by diamminedichloroplatinum].
OBJECTIVE: To study the changes of the ultrastructure of hepatocellular carcinoma (HCC) after being treated by diamminedichloroplatinum. METHODS: The changes of morphological feature of HCC treated by diamminedichloroplatinum were observed with transmission electron microscope. RESULTS: The cells lost its specialized cell surface elements such as microvilli and cell-cell junctions. The nucleus chromatin condensed and segregated. The cytoplasm was hollow. The ribosomes on the endoplasmic reticulum reduced or lacked. The glycogen granules reduced. The mitochondria vacuolalized or produced flocculi, and the apoptotic bodies could be found. CONCLUSION: The changes of the ultrastructure of HCC treated by diamminedichloroplatinum correspond with the procedure of programmed cell death. Apoptosis of HCC cells can be induced by diamminedichloroplatinum.
Adult↗
Obliterated processus vaginalis diagnosed by intraoperative laparoscopy is unlikely to develop into a clinical hernia.
BACKGROUND: This study was conducted to evaluate if a subsequent inguinal hernia would occur in the contralateral obliterated processus vaginalis shown by intraoperative laparoscopic examination. METHODS: From July, 1993 to February, 1994, 120 patients with a unilateral inguinal hernia were identified as obliterated processus vaginalis by intraoperative laparoscopic examination of the contralateral internal ring when they received unilateral herniorrhaphy. A five-year follow-up of the contralateral side to determine the rate of subsequent inguinal hernia was carried out during an outpatient clinic check-up or by telephone contact. RESULTS: One patient, among the first few patients having laparoscopic examinations, had a subsequent contralateral inguinal hernia. Two patients had hydroceles and each of the operative findings was a communicating hydrocele that could not possibly develop into a clinical hernia. CONCLUSIONS: It is unlikely for an obliterated processus vaginalis indicated by intraoperative laparoscopic examination to become a clinical inguinal hernia.
Adolescent↗
[Light effect of gaps in Huangshan pine community and regeneration of Huangshan pine].
This paper dealt with the gaps of Huangshan pine(Pinus taiwanensis) forest developed on the meadow of 1400-1600 m above sea level of Huangshan Mountain. The method of analyzing annual ring growth of pine trees surrounding gaps was employed to estimate the time of gap formation, which was almost the same as the regeneration occurred there. The dynamic variations of total radiation and photosynthetic available radiation(PAR) at different points in gaps were measured, and a regression model for their estimation based on gap size, expanded gap size and canopy closure situation overhead the extended gap was established. The results indicated that the total radiation and PAR were respectively 90% and 71% of full sunlight in gap center, and 30-40% and 25-33% in expanded gaps, while the light under canopy was less than 10% of full sunlight. In the gaps with an area of 40 m2 or in the extended gaps with an area of 110 m2, the light might basically satisfy the growth of the pine, and the gap regeneration could occur. It is suggested that man-made gaps could be made to facilitate the regeneration of Huangshan pine, which could be used as a management approach for Huangshan pine forests, and also for maintaining the landscape in beauty spots of Huangshan Mountain.
China↗
[Benign tumor of duodenum: report of 8 cases].
OBJECTIVE: To investigate the problems of diagnosis and treatment in patients with benign tumor of duodenum. METHOD: Clinico pathological data of 8 patients with benign tumors of duodenum treated surgically in our department from 1989 to 2000 were analyzed retrospectively. RESULTS: Of the 8 patients, 3 had a Brunner's grand adenoma, 2 leiomyoma, 2 mesenchymoma, and 1 lipoma. In general, the patients were asymptomatic and the lesions were discovered incidentally. Gastrointestinal bleeding might be the main symptom even if it was nonspecific. Bleeding might be melena or hematemesis and the patients might develop signs of anemia. Upper gastrointestinal tract examination and gastroduodenoscopy was performed before operation in 7 patients. The tumor was removed through longitudinal incision during duodenotomy. CONCLUSIONS: Gastrointestinal bleeding is common in patients with benign tumor of duodenum. The upper gastrointestinal tract examination and gastroduodenoscopy are major methods for diagnosis. The best treatment of choice is local resection.
Duodenal Neoplasms↗
[Time course of TGF beta 1 and VEGF expression in experimental vein grafts].
OBJECTIVE: To investigate time course of TGF beta(1) and VEGF expression and their role in intimal hyperplasia. METHODS: In situ hybridization and immunohistochemical technique were used to detect the time course of intimal hyperplasia, time course of TGF beta(1) mRNA and protein expression of TGF beta(1) and VEGF. RESULTS: After autogenous vein replacement, the obvious neointima was seen at 2 weeks, and peaked at 8 weeks. The expression of TGF beta(1) mRNA peaked at 1 week and decreased gradually, but at 10 weeks, its positive cell percentage was still 10.1%. Both protein expression of TGF beta(1) and VEGF in VSMCs increased from 24 hours after grafting and peaked at 2 weeks. Their positive cell percentages were 40.6% and 36.6% respectively. After 4 weeks, their expression decreased at 8 weeks, the positive cell percentages were 8.9% and 13.8% respectively. CONCLUSIONS: TGF beta(1) plays an important part in ECM accumulation by promoting ECM synthesis and decreasing ECM degradation. VEGF plays the key role in reendothelialization. They may affect each other and cooperated in the formation of intimal hyperplasia.
Animals↗
[Speech recognition and language development in prelingually deafened children with multichannel cochlear prosthesis].
OBJECTIVE: To assess the development of hearing and language in prelingually deafened children with implanted multichannel cochlear prosthesis from the mandarin-speaking area, and to explore the basic pattern of speech recognition and language development as well as influencing factors. METHODS: Twenty-five prelingually deafened children and youths with cochlear implant participated in this study. Using "Evaluating method on hearing and speech rehabilitation in deafened children" as a test material. These materials consist of speech and environment sound discrimination, closed-set and open-set speech recognition and language development tests. RESULTS: All patients had the ability to hear sound and could discriminate different categorical sounds. Results indicated that the score of closed-set test exceeded the chance level. The correct recognition rate was escalating with prolonging the implanted time. Contrarily, the correct recognition rate was de-escalating as implanted age increased. Subjects having significant open-set speech recognition half year after the operation, indicated that the cochlear implant can promote prelingually deafened children to develop their speech level. CONCLUSION: Once the diagnosis of profoundly sensorineural hearing loss is made, the optimal treatment of choices is cochlear implant and speech rehabilitation.
Adolescent↗
[Study on the meteorologic epidemiology and its prospect].
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China↗
Oxidative refolding of recombinant prochymosin.
The disulphide-coupled refolding of recombinant prochymosin from Escherichia coli inclusion bodies was investigated. Prochymosin solubilized from inclusion bodies is endowed with free thiol groups and disulphide bonds. This partially reduced form undergoes renaturation more efficiently than the fully reduced form, suggesting that some native structural elements existing in inclusion bodies and remaining after denaturation function as nuclei to initiate correct refolding. This assumption is supported by the finding that in the solubilized prochymosin molecule the cysteine residues located in the N-terminal domain of the protein are not incorrectly paired with the other cysteines in the C-terminal domain. Addition of GSH/GSSG into the refolding system facilitates disulphide rearrangement and thus enhances renaturation, especially for the fully reduced prochymosin. Based on the results described in this and previous papers [Tang, Zhang and Yang (1994) Biochem. J. 301, 17-20], a model to depict the refolding process of prochymosin is proposed. Briefly, the refolding process of prochymosin consists of two stages: the formation and rearrangement of disulphide bonds occurs at the first stage in a pH11 buffer, whereas the formation and adjustment of tertiary structure leading to the native conformation takes place at the second stage at pH8. The pH11 conditions help polypeptides to refold in such a way as to favour the formation of native disulphide bonds. Disulphide rearrangement, the rate-limiting step during refolding, can be achieved by thiol/disulphide exchange initiated by free thiol groups present in the prochymosin polypeptide, GSH/GSSG or protein disulphide isomerase.
Air↗
A mechanistic study of self-inactivation of the peroxidase activity in prostaglandin H synthase-1.
Prostaglandin H synthase (PGHS) is a self-activating and self-inactivating enzyme. Both the peroxidase and cyclooxygenase activities have a limited number of catalytic turnovers. Sequential stopped-flow measurements were used to analyze the kinetics of PGHS-1 peroxidase self-inactivation during reaction with several different hydroperoxides. The inactivation followed single exponential kinetics, with a first-order rate constant of 0.2-0.5 s-1 at 24 degrees C. This rate was independent of the peroxide species and concentration used, strongly suggesting that the self-inactivation process originates after formation of Compound I and probably with Intermediate II, which contains an oxyferryl heme and a tyrosyl radical. Kinetic scan and rapid scan experiments were used to monitor the heme changes during the inactivation process. The results from both experiments converged to a simple, linear, two-step mechanism in which Intermediate II is first converted in a faster step (0.5-2 s-1) to a new compound, Intermediate III, which undergoes a subsequent slower (0.01-0.05 s-1) transition to a terminal species. Rapid-quench and high pressure liquid chromatography analysis indicated that Intermediate III likely retains an intact heme group that is not covalently linked with the PGHS-1 protein.
Animals↗
A modified technique to correct primary vesicoureteral reflux in children.
PURPOSE: The authors describe the experience of a modified technique to correct primary vesicoureteral reflux in children. METHODS: Twenty children (28 renal units) with primary vesicoureteral reflux (grade III to grade IV) were treated with this technique. The authors incised the bladder mucosa and muscle along the direction of the ureter using a right-angled probe as a guide. About 2 to 3 cm of extravesical ureter was freed and pulled into the bladder via the incision. The bladder muscle was closed under the ureter, and the mucosa was repaired over the ureter. RESULTS: One patient had residual reflux. All other patients, who underwent follow-up with sonogram and voiding cystourethrogram from 14 to 42 months after the operation, had neither recurrent reflux nor urinary tract obstruction. CONCLUSIONS: The advantages of this technique are (1) anastomosis of the ureteral orifice to the urinary bladder is not needed, so that the risk of orifice stenosis is minimized; (2) the ureteral orifice remains unchanged after the procedure, so that ureteroscopic procedures are easier to perform in future if required; and (3) pelvic dissection is not needed as in extravesical detrusorrhaphy. However, this procedure may not be suitable for patients with severe hydroureter.
Child↗
Contralateral reflux after unilateral ureteral reimplantation--preexistent rather than new-onset reflux.
PURPOSE: The authors studied the preoperative Technetium 99m-dimercaptosuccinic acid renal scan (DMSA) of patients undergoing unilateral vesicoureteral antireflux surgery to compare the amount of renal scarring between the refluxing and the contralateral renal units. They sought to determine whether postoperative contralateral vesicoureteral reflux was preexistent or new onset. METHODS: Sixty-eight patients who underwent unilateral vesicoureteral antireflux surgery and had preoperative DMSA and postoperative voiding cystourethrography (VCUG) examinations were studied. Preoperative DMSA results were analyzed to determine the amount of renal scarring in each kidney. RESULTS: Sixty-four (94.1%) ipsilateral refluxing renal units had renal scars. Of the 68 contralateral renal units, scars were noted in 28 (41.2%). The rate of nonscar was 4 of 68 (5.9%) in reflux kidneys, which was significantly lower than 40 of 64 (62.5%, excluding 4 with a history of resolved reflux) in nonreflux kidneys (P<.001). Of 40 contralateral nonscarred kidneys, 1 of 40 (2.5%) had subsequent reflux, which was significantly lower than 5 of 28 (17.9%) of scarred kidneys (P<.005). Six patients (8.8%) had contralateral reflux, and 1 of them had a history of resolved reflux. Of the 6 contralateral kidneys with severe scarring involving 3 poles or contracted, 4 of 6 (66.7%) had subsequent reflux. CONCLUSIONS: Scar in the contralateral kidney seen on DMSA scan seems to predict contralateral reflux after unilateral antireflux surgery. The contralateral reflux may be preexistent. Postoperative VCUG should be performed routinely for patients who have contralateral renal scars. In patients with a history of contralateral reflux or severe contralateral renal scar, simultaneous contralateral ureteral reimplantation should be considered.
Adolescent↗