Biomedical subjects

C Wei

Publications and source records attributed to C Wei.

At least 73 records · Page 4Linked to original sources

PubMed1999

Increased p53 protein expression in human failing myocardium.

BACKGROUND: The p53 gene is a tumor-suppressor gene which involves apoptosis and cell-cycle arrest under certain stress stimulate. However, the status of the p53 gene expression in human myocardium in congestive heart failure (CHF) remains unclear. Therefore, the current study was designed to investigate the expression of the p53 protein in human myocardium in normal subjects and in patients with severe CHF. METHODS: Human ventricular cardiac tissue was obtained from 7 normal subjects and 7 end-stage CHF patients during cardiac transplantation. The expression of p53 protein was determined by immunohistochemical staining. The cardiac apoptosis was determined by TUNEL staining. RESULTS: The p53 protein was minimally stained in normal human ventricular cardiomyocytes. In contrast, the staining density and positive stained nuclear (%) of p53 was significantly increased in ventricular cardiomyocytes of patients with severe CHF. Apoptosis in CHF human myocardium also markedly increased. CONCLUSIONS: The significantly increased expression of p53 in CHF human cardiomyocytes suggests that p53 may play an important pathophysiological role in the process of CHF through mechanisms involving myocardial apoptosis.

Adult↗

PubMed1999

Water ascent in plants: do ongoing controversies have a sound basis?

The cohesion-tension theory of the ascent of sap in plants is fundamental to the understanding of water movement in plants. According to the theory, water is pulled upwards by high tensions (low negative pressures) created in the xylem vessels and tracheids of higher plants by the evaporation of water vapour from leaves. However, much lower tensions (less negative pressures) have been found from direct measurements using a pressure probe. These do not appear to be compatible with the cohesion-tension theory. As a consequence, the validity of the cohesion-tension theory has been questioned and alternative mechanisms for sap ascent have been proposed. Recent experiments show that the conclusions drawn from the pressure probe work were premature. New direct measurements of xylem pressure support the cohesion-tension theory and the previous indirect measurements of xylem pressure.

Journal Article↗

PubMed1999

Postchemotherapy retroperitoneal residual mass in infantile yolk sac tumor.

BACKGROUND: Persistent postchemotherapy retroperitoneal residual mass with normalization of alpha-fetoprotein (AFP) in infantile yolk sac tumor is rare. METHODS/RESULTS: A 38-month-old boy with recurrent yolk sac tumor was treated with cisplatin-based combination chemotherapy. After chemotherapy, the retroperitoneal lymph node metastasis, 7 x 6 cm in size, decreased to 2 x 2 cm. Serum AFP levels returned to normal. The retroperitoneal residual mass was resected and histologically showed complete necrosis without viable cancer cells. CONCLUSION: The patient has remained free of disease for 36 months after operation.

Antineoplastic Agents↗

PubMed1999

Direct measurement of xylem pressure in leaves of intact maize plants. A test of the cohesion-tension theory taking hydraulic architecture into consideration

The water relations of maize (Zea mays L. cv Helix) were documented in terms of hydraulic architecture and xylem pressure. A high-pressure flowmeter was used to characterize the hydraulic resistances of the root, stalk, and leaves. Xylem pressure measurements were made with a Scholander-Hammel pressure bomb and with a cell pressure probe. Evaporation rates were measured by gas exchange and by gravimetric measurements. Xylem pressure was altered by changing the light intensity, by controlling irrigation, or by gas pressure applied to the soil mass (using a root pressure bomb). Xylem pressure measured by the cell pressure probe and by the pressure bomb agreed over the entire measured range of 0 to -0.7 MPa. Experiments were consistent with the cohesion-tension theory. Xylem pressure changed rapidly and reversibly with changes in light intensity and root-bomb pressure. Increasing the root-bomb pressure increased the evaporation rate slightly when xylem pressure was negative and increased water flow rate through the shoots dramatically when xylem pressure was positive and guttation was observed. The hydraulic architecture model could predict all observed changes in water flow rate and xylem. We measured the cavitation threshold for oil- and water-filled pressure probes and provide some suggestions for improvement.

Journal Article↗

PubMed1999

Observations after orchiectomy in clinical stage I nonseminomatous germ cell tumors of the testis.

BACKGROUND: The optimal management of clinical stage I nonseminomatous germ cell tumor (NSGCT) of the testis remains controversial. For years, retroperitoneal lymph node dissection in combination with orchiectomy, has been the standard treatment in patients with clinical stage I NSGCT. Recently, with advancement of effective cisplatin-based chemotherapy and clinical staging procedures, a new approach of observation after orchiectomy is being evaluated. We reviewed cases of orchiectomy and observation for clinical stage I NSGCT of the testis in order to evaluate the treatment outcome. METHODS: We retrospectively reviewed the records of 13 patients with clinical stage I NSGCT of the testis treated at our hospital from February, 1981 to August, 1996. The patient age at diagnosis ranged from 0.6 to 44 years. Nine patients had yolk sac tumors, and four had mixed germ cell tumors. Median follow-up was 42 months (range, 20-132 months). RESULTS: Prior to orchiectomy, serum beta-human chorionic gonadotropin and alpha-fetoprotein (AFP) were raised to abnormal concentrations in four and in 13 patients, respectively. With a median follow-up of 42 months, three of 13 patients relapsed at a median of three months after orchiectomy. Two patients showed elevated AFP and radiographically identifiable tumors simultaneously, and one patient showed elevated AFP as the only evidence of relapse. Following treatment with cisplatin-based chemotherapy, the three patients who relapsed responded successfully and the elevated AFP returned to normal. The patients are currently alive and disease free. CONCLUSIONS: Observation after orchiectomy is a reasonable approach for patients with clinical stage I NSGCT of the testis.

Adolescent↗

PubMed1999

[Investigation of Y chromosome and polymorphism of 5 Chinese ethnic groups in Yunnan Province, China].

OBJECTIVE: To investigate the polymorphism of DYS287 in the Han, Dai, Lahu, Wa and Tibetan groups living in Yunnan Province, China. METHODS: YAP element was detected by PCR amplification and agarose gel electrophoresis. RESULTS: With 150bp product in all Han,Dai, Lahu and Wa individuals, YAP element is absent. In 11 Tibetan individuals out of 30, YAP element is present and the PCR product is 455bp. CONCLUSION: As an important and stable genetic marker, DYS287 can provide reliable evidence in evolution study.

China↗

PubMed1999

A novel gene: sawD related to the differentiation of streptomyces ansochromogenes.

A 1.3 kb DNA fragment was cloned from a total DNA library of Streptomyces ansochromogenes using Southern hybridization. Nucleotide sequencing analysis indicated that the 1320 bp DNA fragment contained a complete open reading frame (ORF). In search of databases, the deduced product of ORF containing 213 amino acids is homologous to the serine protease of Caulobacter cresceatus, and a conserved serine-catalytic active site (GPSAG) exists. The gene was designated as sawD. The function of this gene was studied with the strategy of gene disruption, and the result showed that the sawD may be related to sporulation and especially to the spore septation in Streptomyces ansochromogenes. The preliminary result indicated that sawD mutant could produce abundant pigment in contrast with the wild type, it seems that sawD gene may be involved in pigment biosynthesis, and this gene is also dispensable for biosynthesis of nikkomycin in Streptomyces ansochromogenes.

Amino Acid Sequence↗

PubMed1999

[Cleaning cavity operation in treating relapse bacillary cavitary pulmonary tuberculosis].

OBJECTIVE: To study the effective surgical way for serious relapse multidrug resistant bacillary cavitary pulmonary tuberculosis. METHODS: 104 cases of serious relapse multidrug resistant bacillary cavitary pulmonary tuberculosis were cured by cleaning cavity operation from 1981 to 1998. The operation contained resecting the back rib covering the cavity, separating the intercostal tissue, cutting the external wall of the cavity, cleaning the cavity thoroughly, scraping the cavity till exposing the fresh tissue, killing the tuberculosis germs with organic acid, filling the cavity with the intercostal muscle, fixing and suturing the muscles. RESULTS: Among the 104 cases, 103 cases (99.0%) were cured, 101 cases (98.1%) were cured after the first operation, one case (1.0%) became better. Among the 98 cases followed up, the rate of returning to work were 96%, no one died or relapsed. CONCLUSIONS: The design of cleaning cavity operation is reasonable and it is the effective method to treat the relapse bacillary cavitary pulmonary tuberculosis, the rate of cure and sputum conversion are promising.

Adult↗

PubMed1999

[Relationship between PDGF-A, bFGF and proliferation of smooth muscle cells in vein grafts].

OBJECTIVE: To detect the relationship between platelet-derived growth factor-A (PDGF-A), basic fibroblast growth factor (bFGF), and proliferation of smooth muscle cells in vein grafts. METHODS: An animal model of autogenous vein graft was established by transplanting internal branch of the jugular vein to the common iliac artery by end-to-end anastomosis. 25 rats were used. The grafted veins were harvested at 6 h, 2 d, 1 w, 2 w and 4 w respectively after the operation. The expression of PDGF-A and bFGF in different stages after grafting procedure was observed immunohistochemically. RESULTS: The expression of PDGF-A peaked at 1 w, paralleled with proliferation of SMC, and was significantly higher than that at 6 h (P < 0.01). The expression of PDGF-A diminished gradually. At 4 w, it was significantly lower than that at 1 w (P < 0.01). bFGF demonstrated bimodal pattern of the expression: the first peak of expression occurred by 2 d and the second peak by 2 w. The difference was significantly compared with other stages. CONCLUSIONS: The expression of PDGF-A 1 contributed to migration and proliferation of SMC. Except for contributing to proliferation of SMC, bFGF perhaps took part in endothelization.

Animals↗

PubMed1999

[Effects and applications of ascorbic acid on the proliferation of Chlamydia trachomatis].

Two hundred and eighty-eight samples of patients with nongonococcal urethritis (NGU) and prostatitis were detected by cell culture and immunofluorescence assay for Chlamydia trachomatis (CT) and the effects of ascorbic acid(vitC) on the formation rate of inclusion of CT in positive samples were also studied. The results showed that the formation rate of inclusion of CT was 29.5% when the concentration of vitC was 5 micrograms.ml-1. The difference between test group and control group which contained cycloheximide in the media was insignificant (P > 0.05). The results suggested that vitC was a kind of nutrient needed for CT. The proliferation of CT in the cell can be promoted by vitC. We can replace cycloheximide by vitC in McCoy cell culture to detect clinic samples with CT.

Adult↗

PubMed1999

[The expression of IGF-I, TGF beta and Fas-L in granulosa cells of ovarian follicle with relation to the onset of atresia in rats].

This study was designed to investigate the effects of IGF-I, TGF beta and Fas-L on the sustaining of granulosa cells of ovarian follicle and the modulation of apoptosis of those cells, and to understand the molecular mechanisms of ovarian follicle atresia. Paraffin-embedded sections of SD rat ovary were made. Both TUNEL method and PCNA immunohistochemistry were employed to recognize atretic and healthy follicles. The expression of IGF-I, TGF beta, Fas-L and their receptors was displayed by immunostaining. The results showed that most of the granulosa cells within the healthy preantral and antral follicles were PCNA(+). At the early stage of atretic antral follicle, more than 5 granulosa cells were labelled by TUNEL method, and some granulosa cells were PCNA(+). At the late stage of atretic antral follicle, were labelled by TUNEL method. The immunoreactive products of IGF-I, IGF-IR, TGF beta, TGF beta R, Fas and Fas-L could be seen in the granulosa cells of healthy antral follicles. But, Granulosa cells were only TGF beta, TGF beta R and Fas immunopositive in all atretic antral follicles. In conclusion, combination of TUNEL method and PCNA immunochemistry is of benefit for distinguishing atretic follicles from healthy follicles. IGF-I might play an important role in stimulating proliferation of the granulosa cells and sustaining them. The lower expression or disappearance of IGF-I in the antral follicle might cause the onset of atresia. TGF beta, Fas-L and Fas might mediate apoptosis of the granulosa cells in antral follicles, causing follicle atresia. But, their effects of mediation could be inhibited as IGF-I exists in the follicles.

Animals↗

PubMed1999

[The influences of vowel ae and a: on acoustic measures].

OBJECTIVE: To study the influences of vowel ae and a: on acoustics measures. METHOD: Fifty-three cases of laryngeal diseases were measured acoustically. The acoustic sampling were vowels ae and a:. RESULT: The results showed that Fo, Jitter and Shimmer were similar between two groups, and NNE of vowel a: was much lower than that of ae, indicating larger glottal closure in vowel a:. CONCLUSION: Vowels have something to do with glottal closure, therefore influencs acoustical measures.

Acoustics↗

PubMed1999

[Quantitative analysis of vocal fold vibration].

OBJECTIVE: To measure vocal fold vibration quantitatively and study the effects of gender and phonation mode. METHOD: The authors adopted a new computerized image analysis technique and EGG in 60 normal speakers, and the parameters of vocal fold vibration were measured and analyzed according to the loudness, pitch and gender. RESULT: With frequency increasing, CQ got smaller and OQ larger which expressed longer open phase. As intensity increased, the duration of open phase became shorter and the closing phase got relatively much shorter. Males had a longer closed phase than females. The closing duration appeared relatively shorter than opening duration in phonation. CONCLUSION: The quantitative measures of vocal fold vibration become feasible with modern computers and commercially available image analysis software. Certain features of vocal fold vibration vary with intensity variations, while others vary with gender or frequency variation.

Adolescent↗

PubMed1999

[Rate discrimination and tone recognition in mandarin-speaking cochlear-implant listeners].

OBJECTIVE: To explore the relationship between the rate discrimination and the tone recognition with psychophysical method, and provide a basis for evaluating the results from mandarin-speaking cochlear implantees who used multi-channel cochlear implant and designing new speech coding strategies of the speech processor. METHODS: Four postlingually-deafened adults with cochlear implant participated in this study. We used the method of constant stimuli to measure the rate discrimination as a function of the standard rate at 50, 100, 200, 400 Hz on electrode pairs (E1, E3), (E7, E9), (E14, E16), and (E20, E22), respectively. We also measured tone recognition in 25 consonant-vowel syllables, each of which has four tonal variations, resulting in a total of 100 words. These words were recorded by a male talker and were presented five times each to the implant users via their speech processors. The tone recognition results were scored in overall percent correct and analyzed by error patterns in the confusion matrix and fundamental frequency. RESULTS: The rate discrimination thresholds, defined at the 75% correct level, varied greatly among individuals and ranged from several Hz to hundreds of Hz. A three-way ANOVA indicated significant effect (P < 0.05) on rate discrimination for the standard rate, electrode position, and patient variable. The tone recognition ranged from 40% to 80% and tones 1 and 3 were more easily identified than tones 2 and 4. Preliminary analysis using linear regression revealed highly significant correlation between rate discrimination and tone recognition. CONCLUSION: These results suggest that identification of tones relies on good rate discrimination in cochlear implant listeners. Clinical rehabilitation strategies in improving rate discrimination were discussed.

Adult↗

PubMed1998

Surgical treatment of vesicoureteral reflux in infants under 3 months of age.

PURPOSE: Surgical treatment for vesicoureteral reflux (VUR) is controversial in infants, especially small infants because of technical difficulty and higher rate of spontaneous resolution. However, in some conditions, such as high-grade reflux, breakthrough infection, or severe renal scarring, early operation may be justified. This study is to evaluate the results of ureteral reimplantation in infants with VUR under 3 months of age. METHODS: From January 1993 to July 1997, 13 boys and five girls (24 ureters) under 3 months of age (range, 18 days to 3 months; mean age, 2 months) received ureteral reimplantation for VUR. The initial symptoms were urinary tract infection (UTI) in 16 infants, hydronephrosis found by prenatal ultrasound scan in one, and early postnatal screening ultrasound scan in one. The indications for 24 ureter reimplantations were high-grade reflux (grade V, n = 7), breakthrough infection under medical treatment (n = 5), and severe renal scarring (n = 8) and contralateral low-grade refluxing ureters (n = 4). All patients had Glenn-Anderson's or Cohen's ureteral reimplantation. Ureteral stents were required in six ureters. All patients had renal sonogram 1 month after operation to rule out ureteral obstruction. Fifteen patients had voiding cystourethrogram (VCUG) after operation. Renal growth was evaluated in 15 patients (20 reflux renal units) using serial ultrasound or differential perfusion renal scan. The operative time, use of ureteral stent, complication rate, hospital stay, and time needed for clearing urine, were compared with those of 115 counterpart patients at age over 3 months. Data were analyzed using X(2) test or t test. RESULTS: All patients, except one, were free of UTI during the follow-up of 6 months to 5 years. In fifteen infants who had postoperative VCUG, 14 were free of reflux, and one had persistent lower-grade VUR. One patient had transient ureteral obstruction that resolved spontaneously. One patient had postoperative ileus for 2 weeks. Renal growth of 20 reflux renal units was similar to that of the contralateral nonreflux kidneys. The only significant difference when compared with the patients over 3 months of age, was the higher incidence of ureteral stenting (25% v 4.2%, P<.01). CONCLUSIONS: Ureteral reimplantation should be performed in infants under 3 months of age when it is indicated.

Age Factors↗

PubMed1998

A transgenic strategy for analyzing the regulatory regions of the human prostate-specific antigen gene: potential applications for the treatment of prostate cancer (Review).

Prostate-specific antigen (PSA) has been used clinically as a marker for the diagnosis and staging of prostate cancer due to its specific expression in prostate epithelial cells. In addition to its medical importance, its complex hormonal and tissue-specific regulation makes it an attractive model to study gene regulation. Two approaches have been applied to the identification of regulatory regions which confer this specific expression pattern. In vitro analysis of the regulatory regions of the human PSA gene using promoter reporter constructs and tumor cell lines has revealed a number of the DNA sequences involved in the hormone-dependent expression of PSA. We have pursued an alternative in vivo approach using transgenic animal technology, which is the focus of this review. Using this second approach, a transgenic mouse was generated using a 14 kilobase (kb) region of the human PSA gene encompassing the coding region and intervening sequences as well as 6 kb of upstream sequence and 2 kb of downstream sequence. This genomic DNA clone confers a PSA expression pattern in mice which appears to be very similar if not identical to that of humans, allowing us to investigate tissue-specificity and developmental regulation of PSA expression. In addition, these mice, for which PSA is a self-antigen, provide a model to test the feasibility and efficacy of PSA-directed immunotherapy for prostate cancer. The further identification of the PSA regulatory regions important for tissue-specificity may ultimately allow the design of new therapeutics for the treatment of prostate cancer.

Animals↗

PubMed1998

Regulation of human prostate-specific antigen gene expression in transgenic mice: evidence for an enhancer between the PSA and human glandular kallikrein-1 genes.

The human prostate-specific antigen (PSA) and glandular kallikrein-1 (hGK-1, also known as hK2) genes are tandemly located on chromosome 19, separated by a 12-kb intergenic region. The coordinate regulation of these two genes suggests the presence of common regulatory elements responsible for tissue specificity and/or levels of expression within this region. To identify such regulatory elements, we generated two sets of transgenic mice, which had incorporated either the PSA gene alone or together with the intergenic region. Both sets of transgenics exhibit remarkably prostate-specific expression of the transgene. However, the presence of the intergenic region abrogates the dependence on high PSA gene copy-number for high levels of PSA expression. This suggests the existence of a positive regulatory element in the intergenic region. By using a previously identified distal enhancer element of PSA (termed DEE 1) as a probe, we identified a cross-hybridizing fragment, which we termed DEE 2, in the intergenic region. Sequence analysis shows that DEE 2 is 76% identical to DEE 1, and it includes a putative androgen-responsive element. Here, we propose a model to illustrate how the two enhancers may work to regulate the transcription of PSA and hK2.

Animals↗

PubMed1998

[Relationship between hematocrit (Hct) and cardiac systolic time intervals (STI) in residents at 4300 m altitude].

In order to study the relationship between Hct and cardiac systolic time intervals (STI) in residents at high altitude, STI and cardiac function were determined by electrical impedance and carotid arteriogram in 113 subjects with different Hct at an altitude of 4300 m. There was a negative correlation between Hct and SV or EF (r = -0.841 and -0.628), respectively (P < 0.001). With increase of Hct there were prolonged pre-ejection period (PEP), shortened left ventricular ejection time (LVET), and increased PEP/LVET. SV, CO were lower in high altitude polycythemia (HAPC) than in the control (P < 0.05). It demonstrated that there is a close relationship between STI and Hct, and excessive polycythemia is one of the important factors that cause decrease of cardiac function decreasing in high altitude residents.

Adolescent↗