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Biomedical subjects

T C Wu

Publications and source records attributed to T C Wu.

At least 145 records · Page 8Linked to original sources
PubMed1993

Study of Epstein-Barr virus early RNA 1 (EBER1) expression by in situ hybridization in thymic epithelial tumors of Chinese patients in Taiwan.

Forty-one thymic epithelial tumors from Chinese patients in Taiwan, including 14 noninvasive thymomas, seven invasive thymomas, and 20 thymic carcinomas, were investigated for the presence of Epstein-Barr virus transcripts by in situ hybridization using digoxigenin-labeled riboprobes for EBER1 expressions. None of the 14 noninvasive thymomas or seven invasive thymomas had detectable EBER1. Only one of 20 thymic carcinomas was positive for EBER1. This positive tumor was a lymphoepithelioma-like carcinoma found in a 19-year-old patient. Four different cases of lymphoepithelioma-like carcinoma were negative. Of note, the present case and all previously reported cases of Epstein-Barr virus-associated thymic carcinomas were lymphoepithelioma-like carcinomas. These results are consistent with those of several Western studies and do not support the view that there are geographic or racial differences affecting the role of Epstein-Barr virus in the pathogenesis of thymic epithelial tumors.

Adult↗
PubMed1993

Enhanced ovarian inhibin subunit gene expression in aging rats is due to chronic anovulation.

The persistent-estrous (PE) state in aging rats, characterized by a lack of ovulation and absence of estrous cycles, is associated with enhanced inhibin alpha and beta A subunit mRNA expression in the ovaries. It has been shown that the PE state can be interrupted by successive treatments with a progesterone implant (P-implant) and that estrous cycles can be transiently restored after implant removal. The present study examined whether restoration of estrous cycles in PE rats could reverse the altered ovarian inhibin alpha and beta A subunit gene expression. PE rats were treated with subcutaneous P-implants for 6 wk. After implant removal, the return of estrous cyclicity was confirmed by characteristic cyclic changes in vaginal cytology. Ovaries collected from the P-implant-treated animals at 1100 h on diestrus Day 2 or proestrus showed significantly decreased levels of both inhibin alpha and beta A subunit mRNAs compared to those of PE controls and young cyclic females. In situ hybridization revealed that the decreased inhibin alpha subunit mRNA after P-implants was due to decreased gene expression in the granulosa cells of large preovulatory follicles and to a compete absence of gene expression in large, cystic follicles devoid of granulosa cells and oocytes. In addition, inhibin alpha subunit mRNA was expressed in the newly developed follicles after implant removal. The beta A subunit mRNA was detected only in maturing follicles, not in newly developing follicles or in the large cystic follicles. The patterns of ovarian inhibin alpha and beta A subunit gene expression mimicked those of cyclic animals. These data indicate that loss of estrous cycles in aging rats results in an overexpression of inhibin alpha and beta A mRNAs in large and anovulatory follicles and that reinstatement of ovarian cycles in aged rats restores inhibin gene expression to normal levels.

Aging↗
PubMed1993

Inhibin subunit gene expression and distribution in the ovaries of immature, young adult, middle-aged, and old female rats.

In young adult female rats, the patterns of inhibin subunit mRNA expression during the estrous cycle are regulated by cyclic changes in gonadotropin secretion and follicular development. Since there are distinct alterations in profiles of both hormone secretion and folliculogenesis during the reproductive lifespan of the female rat, we have characterized the gene expression and distribution of inhibin subunit mRNAs in immature (22 days), young adult cyclic (3-4 months), middle-aged cyclic (9-10 months), and old (12-13 months) persistent estrous (PE) rat ovaries. Northern blot analyses revealed that in contrast to young adult cyclic rats, inhibin alpha- and beta A-subunit mRNA levels in the ovaries of middle-aged cyclic rats remained substantially elevated after the proestrous gonadotropin surges and ovulation. Likewise, acyclic immature and old PE rats showed high levels of inhibin alpha- and beta A-subunit transcripts in their ovaries. In situ hybridization analyses demonstrated that inhibin alpha- and beta A mRNAs were abundantly expressed in maturing follicles of both young and middle-aged cyclic females, while high levels of alpha-subunit transcripts were only detected in the ovarian stroma of middle-aged animals. The ovaries of old PE rats had numerous large cystic follicles (with variable layers of granulosa cells) and few degenerating cyst-like structures (completely devoid of granulosa cells). Inhibin subunit transcripts were expressed abundantly in both the granulosa (alpha and beta A-subunits) and theca interna (alpha-subunit only) layers of large follicles, but were absent from degenerating cysts devoid of granulosa cells. The ovarian stroma of PE rats also expressed very high levels of inhibin-alpha, but not beta A mRNA. The ovaries of immature rats contained large numbers of uniformly developing secondary follicles. High levels of inhibin-alpha mRNA were expressed homogeneously in the granulosa layer of all growing follicles, whereas inhibin beta A mRNAs were only detected in selectively larger follicles with multiple layers of granulosa cells. Hormone RIAs of serum samples from these same groups of animals showed that basal levels of serum FSH were substantially higher in immature, middle-aged cyclic, and old PE rats than in young adult rats. These results demonstrate that enhanced ovarian inhibin subunit gene expression in the female rat is associated with increased serum FSH levels regardless of chronological age. On the other hand, aging appears to selectively enhance inhibin alpha, but not beta A, gene expression in the ovarian stroma, such that it may gradually become a major secondary site of alpha-subunit mRNA production in addition to the follicular compartments.

Aging↗
PubMed1993

Detection of estrogen receptor messenger ribonucleic acid in human oocytes and cumulus-oocyte complexes using reverse transcriptase-polymerase chain reaction.

OBJECTIVES: To examine the expression of estrogen receptor (ER) messenger ribonucleic acid in the human ovary. To detect ER gene transcripts in human oocytes; and to study the possible autocrine effect of estrogen (E) in granulosa/cumulus cells. DESIGN: Human ovaries from benign gynecological surgeries as well as the oocytes, cumulus-oocyte complexes, and granulosa/cumulus cells from the in vitro fertilization program were used to detect ER gene transcripts using the highly sensitive reverse transcriptase-polymerase chain reaction technique. SETTING: Molecular biology laboratory. RESULTS: The ER gene is expressed in human ovary. Estrogen receptor transcripts were detected in human cumulus-oocyte complexes and oocytes but not in granulosa/cumulus cells. CONCLUSIONS: These results suggest a lack of receptor-mediated autocrine effect of E during folliculogenesis and that E, secreted by granulosa/cumulus cells, may exert a paracrine effect to influence oocyte maturation and fertilization competence directly.

Adult↗
PubMed1993

Emergency department recognition of pulmonary embolism.

The cases of forty-six patients who were admitted via the Emergency Department (ED) with suspected pulmonary embolism (PE), during a ten-year period, were reviewed. Ventilation perfusion lung scans were done in all patients, and pulmonary angiography was performed in 26. Thirty-six PE patients (78%) were correctly diagnosed by emergency physicians. Ten patients (22%) were erroneously diagnosed at the ED but were proved otherwise after hospitalization. The average age of the patients was 54 years, with males dominantly 67%. Overall mortality rate was 8.7%. Predisposing risk factors for PE were documented in 20 patients (43%). Prior history of thrombophlebitis (17%) or pulmonary embolism (13%), and immobilization (13%) were significant. The most common clinical features were dyspnea (76%), pleuritic pain (74%) and hemoptysis (41%). Thirty patients (65%) had tachypnea and 20 patients (43%) had tachycardia. Chest radiographs were abnormal in 35 cases (76%), and abnormal ECG findings were noted in 27 patients (59%). However, these abnormalities of chest radiographs or ECG were not sufficiently specific to confirm or exclude the diagnosis of PE. Noninvasive or contrast venography for deep vein thrombosis were performed in 31 patients (67%), of whom 17 cases (37%) had positive results. All patient received anticoagulation treatment. And six patients had thrombolytic agents as well.

Adolescent↗
PubMed1993

[Perforated peptic ulcer in patients with central nervous system injury].

There were 10 cases of perforated peptic ulcer (PPU) occurring in patients with central nervous system injury from July 1982 to December 1991; 7 cases occurred in intensive care unit whereas 3 cases occurred in the ordinary ward. Because of inability of these patients to express abdominal pain, the diagnosis of PPU was suspected only in the presence of the frequently associated clinical signs such as abdominal distension, fever, tachypnea, tachycardia, and hypotension. Because the diagnosis of PPU in these patients is generally delayed, mortality up to 60% is noted. The diagnosis of PPU was made by chest X-ray with pneumoperitoneum in only 5 of the 10 patients, whereas that of the remaining 5 patients was made by peritoneal lavage with bile-like ascites. There is a good correlation between the presence of shock after PPU and the survival of the patients. We recommend that once there are abnormal abdominal signs, inexplicable hemodynamic changes in patients with central nervous system injury, immediate thorough examination in search of PPU should be made to detect early the life-threatening PPU and to reduce the mortality thereafter.

Adolescent↗
PubMed1993

Dilatation of the biliary tract in pediatric patients.

Forty cases of dilatation of the biliary tract in infants and children were diagnosed and treated at the Veterans General Hospital, Taipei and Taichung between 1980 and 1992. The male to female ratio was 1:2.6 and the age ranged from 1 day to 14 years. Major clinical presentations were abdominal pain (57.5%), jaundice (42.5%), vomiting (37.5%) and abdominal mass (30%); the classical triad of abdominal pain, jaundice and abdominal mass occurred in only three cases (7.5%). Abnormal liver function tests included elevated bilirubin (Bil) (22/37), aminotransferase (30/40), alkaline phosphatase (Alk-P) (34/37), lactic dehydrogenase (LDH) (22/34) and gamma-glutamyl transpeptidase (GGT) (13/15). The amylase in bile was detected in 16 cases with 10 cases higher than 500 Somogyi units/dL. All cases were diagnosed correctly, using real time sonography. Technetium-labeled scintiscan (Tc-99m DISIDA scan) was interpreted correctly in 88% (15/17) and abdominal computerized tomography (CT) in 10 cases (10/10). According to Todani's classification, type I cyst was the most common (35 cases, 87.5%) and the remaining cases were type IV-A (3 cases) and type V (2 cases). Operation was performed in 38 cases except for two who had type V dilatation of biliary tract (Caroli's disease). Complications included rupture of the gall bladder in two patients and common bile duct stone in one; mortality after operation occurred in one case. Surgical specimens of the liver revealed periportal fibrosis in nine instances.

Adolescent↗
PubMed1993

Differential distribution of glycoconjugates in human reproductive tract.

OBJECTIVES: To study the distribution of glycoconjugates in the epithelia of various regions of the human female reproductive tract and to examine whether lectins can be used as specific probes to define cell populations in the human female reproductive tract. DESIGN: Nineteen fluorescein isothiocyanate (FITC)-labeled lectins, which recognize different oligosaccharide structures, were applied to frozen sections of human fallopian tubes (distal and proximal segments) and endometrium. The differential binding patterns of the lectins to the epithelia were evaluated under fluorescent microscopy. RESULTS: Four of 19 FITC-labeled lectins tested demonstrated distinct binding patterns along the reproductive tract. Arachis hypogaea (PNA) and Ricincus communis II selectively reacted with epithelial cells of endometrium and distal, but not proximal tube. In addition, PNA distinguished ciliated from secretory cells of the distal tube. Maclura pomifera binding followed a gradient of decreasing intensity from distal to proximal tube and was negative in the endometrium. Dolichos biflorus reacted exclusively with proximal tubal epithelium. CONCLUSIONS: Analysis of the FITC-lectin binding pattern and the sugar specificities indicate that the distribution of galactosyl residues varies among different regions of the reproductive tract, whereas glucosyl, mannosyl and fucosyl residues are more evenly distributed. The differential expression of glycoconjugates may be involved in the distinct biological function of each region in female reproductive tract.

Endometrium↗
PubMed1993

Detection of a neuron-specific 9.0-kb transcript which shares homology with antisense transcripts of HIV-1 gag gene in patients with and without HIV-1 infection.

The pathogenesis of the neurologic abnormalities associated with the acquired immune deficiency syndrome (AIDS) is poorly understood. Although human immunodeficiency virus type 1 (HIV-1) transcripts have been detected in endothelial cells and macrophages of the central nervous system in patients with AIDS, infection of neuronal cells by HIV-1 has not been established. The purpose of this study was to localize HIV-1 transcripts in the central nervous system. 3H and digoxigenin-UTP-labeled riboprobes generated from a 942-bp fragment of DNA from the 5' end of the HIV-1 gag sequence were used for in situ hybridization. The antisense riboprobe hybridized to lymphoid cells in the sections of kidney and spleen obtained from patients with AIDS, as well as to the HIV-1-infected A3.01 cell line. The control sense probe did not hybridize to these same cells. In contrast, no detectable hybridization was observed to neuronal cells when the antisense probe was applied to sections of brain obtained from patients with and without AIDS. To our surprise, however, specific hybridization was observed to neuronal cells when the control sense probe was applied. This hybridization with the control sense probe was seen in both patients with and without HIV-1 infection. Northern blot analysis confirmed the in situ hybridization results; a unique 9.0-kb transcript was detected exclusively in brain tissue. These data suggest that there is a neuron-specific 9.0-kb transcript that shares extensive homology with antisense gag HIV-1 sequences and that this transcript is expressed in neuronal cells of both HIV-1-infected and noninfected individuals. The biological significance of this 9.0-kb transcript is unknown, but it may play an important role in the interactions of HIV-1 with neuronal cells.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Spontaneous rupture of splenic hemangioma: a case report.

Splenic hemangioma is rare. The major problem concerning splenic hemangioma is the difficulty of preoperative diagnosis. No characteristic signs allow the specific diagnosis of this tumor. Spontaneous rupture is the main complication, occurring in up to 25% of cases reported. In cases of rupture of the tumor, splenectomy is a life-saving and mandatory procedure. A case of spontaneous rupture of splenic cavernous hemangioma is presented and the literature is reviewed.

Adult↗
PubMed1992

Expression of estrogen receptor gene in mouse oocyte and during embryogenesis.

Estrogen is required for oocyte maturation and embryonic development in vivo; however, the mechanism involved is not clear. Since the effect of estrogen is mediated through the estrogen receptor (ER), we examined the ontogeny and expression of the ER gene in mouse oocytes and embryos of various gestational stages using the highly sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Total RNA, extracted from 40 ovulated oocytes, 2-cell embryos, morulae, and blastocysts, was reverse transcribed into cDNA. A pair of primers flanking the 453-bp region encoding the hormone-binding domain of ER was used for 30 cycles of PCR. The identity of the amplified product was confirmed by sizing and Southern blot hybridization. The results indicated that ER gene is expressed in unfertilized oocytes and cumulus-oocyte complexes. The amount of ER mRNA decreases in 2-cell embryos, coincident with degradation of maternal mRNA. No ER transcript can be detected in the morulae or blastocyst stage when the embryonic genome has been activated. Postimplantation embryos do not contain detectable ER mRNA until gestation day 8. The levels of ER mRNA increase from day 10 to day 18 of gestation. These data suggest that estrogen, secreted by granulosa cells, may directly influence oocyte growth and maturation in vivo. Since estrogen is known to stimulate the production of growth factors in mouse uteri, the absence of ER mRNA in periimplantation embryos suggests that the effects of estrogen on early embryogenesis may be indirect, i.e., through estrogen-regulated growth-promoting factors produced by the reproductive tract. In mid- and late-post-implantation embryos which contain ER mRNA, estrogen may affect embryonic development through the receptor-mediated mechanisms.

Animals↗
PubMed1992

Normal N-acetylglutamate concentration measured in liver from a new patient with N-acetylglutamate synthetase deficiency: physiologic and biochemical implications.

N-Acetyl-L-glutamate synthetase (NAG synthetase) is a mitochondrial matrix enzyme which catalyzes the synthesis of N-acetyl-Lglutamate (NAG), a physiologic activator of the urea cycle enzyme carbamylphosphate synthetase I. Deficiency of NAG synthetase in humans has been reported only three times previously. Two cases presented with uncontrolable neonatal hyperammonemia leading to death, while a third child presented with hyperammonemia and a neurodegenerative picture at 15 months of age after previously being healthy. We report here a new case of NAG synthetase deficiency who presented at 4 years, 10 months of age with an episode of hyperammonemia. Diagnosis was made at age 5 years, 6 months when a liver biopsy showed 9.7% of normal activity. Urine orotic acid was low, and total NAG content in liver was normal. Liver pathology revealed micro- and macrovesicular fat and mitochondria of irregular size and shape with intracristae crystallizations. NAG content in liver in patients with NAG synthetase deficiency has not previously been reported. Its normal value in the face of NAG synthetase deficiency suggests an abnormal localization of NAG to the cytoplasm and the likelihood of aberrant cytoplasmic synthesis of this compound. Additional physiologic implications of this speculative abnormal compartmentalization are discussed.

Acetyltransferases↗
PubMed1992

The predictive value of a single, early human chorionic gonadotropin measurement and the influence of maternal age on pregnancy outcome in an infertile population.

A single early quantitative hCG measurement 16 to 18 days after timed insemination has prognostic value with regard to pregnancy outcome in an asymptomatic, infertile population. Further, there is a statistically significant difference in the predictive value for hCG levels in patients less than or equal to 35 years compared with patients greater than 35 years of age. Interestingly, the same age-dependent phenomenon was observed when analyzing the predictive value of sonographically detected fetal heart motion at 5 weeks post-ovulation. We suggest that any investigation on pregnancy outcome, or its prediction should consider the impact of maternal age as a potentially significant covariate.

Adult↗
PubMed1992

Can a single, early quantitative human chorionic gonadotropin measurement in an in vitro fertilization-gamete intrafallopian transfer program predict pregnancy outcome?

STUDY OBJECTIVE: To assess the predictive value of a single serum human chorionic gonadotropin (hCG) measurement obtained on day 14, 15, or 16 after transfer in in vitro fertilization or gamete intrafallopian transfer pregnancies. DESIGN: Retrospective. SETTING: Assisted reproductive technology (ART) programs. PATIENTS: One hundred thirty-four consecutive pregnancies from two ART programs were reviewed. RESULTS: The incidence of livebirth was only 6% when day 14 to 16 hCG values were less than 100 mIU/mL, but increased to 82% with levels greater than 100 mIU/mL (P less than 0.001). The incidence of livebirth and multiple birth correlated with rising hCG levels. Only 1% (1/71) of pregnancies with serum hCG values greater than 100 mIU/mL was ectopic, and this case was a bilateral (double) ectopic. CONCLUSIONS: A single serum hCG measurement obtained 14 to 16 days after embryo or gamete transfer not only is diagnostic but also has good predictive value for pregnancy outcome.

Chorionic Gonadotropin↗
PubMed1992

In situ detection of human cytomegalovirus immediate-early gene transcripts within cardiac myocytes of patients with HIV-associated cardiomyopathy.

OBJECTIVE: Recent clinical and echocardiographic studies have identified dilated cardiomyopathy in 10-20% of HIV-infected adults. The purpose of this study was to determine the role of cardiotropic cytomegalovirus (CMV) infection in the development of HIV-associated cardiomyopathy. DESIGN: We generated sense and antisense digoxigenin-labeled riboprobes derived from the CMV immediate-early (IE) and delayed-early (DE) genes and applied them retrospectively to endomyocardial biopsy samples and control autopsy cardiac samples from HIV-infected patients. SETTING: Tertiary care, referral hospital. PATIENTS: Twelve consecutive HIV-infected patients with global left ventricular hypokinesis demonstrated on two-dimensional echocardiography; eight randomly selected control autopsy cardiac samples from HIV-infected patients without cardiac disease during life. MEASUREMENTS AND MAIN RESULTS: Of the 12 endomyocardial biopsy specimens, six (50%) were found to have specific myocyte nuclear and perinuclear hybridization for transcripts of the CMV IE gene, consistent with non-permissive or latent infection. Similar patterns were not found in any of the eight autopsy control samples. All six patients presented with unexplained congestive heart failure and had CD4 counts less than 100 x 10(6)/l; all six biopsy samples had immunohistochemical evidence of increased myocardial major histocompatibility complex (MHC) class I expression, a finding typical of non-HIV myocarditis. None of the endomyocardial biopsy samples had characteristic CMV inclusions and no specific hybridization was noted with the DE gene riboprobe, suggesting that no active viral DNA replication was present. Only two of the six patients with myocyte hybridization with the IE riboprobe had clinical evidence of solid organ infection with CMV at the time of cardiovascular presentation. CONCLUSIONS: This study is the first to demonstrate the expression of the IE gene of CMV within myocytes from HIV-infected patients with cardiomyopathy, suggesting a non-permissive infection of myocytes without classical intranuclear inclusions. Myocyte infection may be necessary to trigger cellular and humoral-mediated cardiac injury and may be best identified using in situ hybridization techniques.

Adult↗
PubMed1992

The effects of retinoic acid on the expression of alpha-fetoprotein and albumin genes in rat hepatoma cell lines.

Many transcriptional regulators can stimulate or repress gene expression depending on the cellular or genetic contexts. Thus dexamethasone increases the amount of alpha-fetoprotein mRNA in Morris rat hepatoma derived cell line McA-RH 8994 cells, but decreases it in McA-RH 7777 cells. In the present study, we demonstrated that retinoic acid, whose receptors belong to the steroid/thyroid hormone receptor gene family, also enhanced the expression of alpha-fetoprotein and albumin gene in McA-RH 8994 cells, but had no effect on alpha-fetoprotein gene expression in McA-RH 7777 cells. In contrast to the effect of dexamethasone on the alpha-fetoprotein gene expression, which requires ongoing protein synthesis, cycloheximide, a protein synthesis inhibitor, enhanced the effect of retinoic acid. Actinomycin D inhibited the retinoic acid mediated increase in alpha-fetoprotein and albumin mRNA expression. Since the McA-RH 8994 cells did not express retinoic acid receptor beta mRNA, the observed regulatory effects of retinoic acid on alpha-fetoprotein and albumin gene expression were not mediated through retinoic acid receptor beta. We also conclude that the regulation was at the level of transcription and that retinoic acid and dexamethasone probably regulate the expression of liver specific genes through different mechanisms.

Albumins↗
PubMed1992

Retinoic acid regulates gene expression of retinoic acid receptors alpha, beta and gamma in F9 mouse teratocarcinoma cells.

The regulatory effects of retinoic acid (RA) on retinoic acid receptor (RAR) alpha, beta and gamma mRNA were examined in the F9 mouse teratocarcinoma cells. Northern blot hybridization showed that RA regulated all three types of RAR gene expression. The different transcripts for each RAR alpha and beta were differentially regulated by RA. The maximum induction of the 2.8 kb RAR alpha and 3.3 kb RAR beta transcript levels by RA took longer than the induction of the 3.8 kb RAR alpha and 3.5 kb RAR beta transcript levels. The data suggest that these transcripts originated from different promoters. Short term treatment (< or = 24 hours) of RA induced both 3.1 and 3.3 kb RAR gamma transcripts. Long term treatment (> 24 hours) of RA resulted in the inhibition of 3.1 kb mRNA, whereas the 3.3 kb mRNA remained elevated. In addition, a new RAR gamma transcript of 2.9 kb was induced. In contrast to RAR alpha and beta, the effect on RAR gamma gene expression was irreversible. Cycloheximide did not prevent the effect of RA on RAR gene expression, whereas actinomycin D totally abolished the RA effect on the expression of all three receptor genes. The data suggest that the biological effects of RA may be constrained or augmented by differential regulation of its own receptor gene expression.

Animals↗