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Biomedical subjects

T C Wu

Publications and source records attributed to T C Wu.

At least 163 records · Page 9Linked to original sources
PubMed1992

Human papillomavirus in sinonasal papillomas and squamous cell carcinoma.

The diagnostic and prognostic relevance of human papillomavirus (HPV) types 6, 11, 16, and 18 in squamous papilloma, inverted papilloma, and squamous carcinoma of the sinonasal epithelium was examined using the polymerase chain reaction (PCR) technique. Four (15%) of 26 squamous papillomas, 7 (24%) of 29 inverted papillomas, and 1 (4%) of 24 squamous carcinomas were positive for HPV when examined using the PCR amplification technique. Human papillomavirus 6 was present in 5 specimens (3 squamous and 2 inverted papillomas); HPV-11 was present in 6 specimens (1 squamous and 5 inverted papillomas); and HPV-18 was present in 1 of 24 squamous carcinomas. HPV-16 was not identified in any specimen. The proportion of tissue samples showing HPV presence, and the association of HPV types 6 and 11 with benign lesions and HPV-18 with malignant lesions, are both in accord with findings from prior investigations. Two major questions regarding nasal papilloma are the probability for lesion recurrence after surgical excision and the risk for malignant transformation. There is no unanimity of opinion regarding the prognostic value of histopathologic dysplasia to forecast these outcomes. HPV is etiologically related to a subset of sinonasal papillomas and squamous carcinoma, and those with benign and malignant clinical course are separable on basis of HPV type. Because of the paucity of these nasal lesions, a multi-institutional prospective collaborative study is the ideal way to address these questions.

Carcinoma, Squamous Cell↗
PubMed1992

Detection of retinoic acid receptor mRNA in rat tissues by reverse transcriptase-polymerase chain reaction.

The presence of retinoic acid receptor (RAR) alpha, beta and gamma mRNA was examined in 16 different kinds of rat tissue using the highly sensitive reverse transcriptase-polymerase chain reaction technique. The data demonstrated that each tissue expressed at least two types of RAR mRNA. Among the three types of RAR mRNA, RAR alpha was widely expressed in all types of organ and was the dominant form expressed in the gastrointestinal tract. RAR beta mRNA was not present in the intestine and spleen. In addition, RAR beta mRNA levels were high in the heart, lung, brain, testis and epididymis. RAR gamma mRNA was abundant in both male and female reproductive systems, as well as epidermal tissues. The prevalence of each RAR mRNA in the tissues suggests the diverse biological roles of these receptors.

Animals↗
PubMed1992

Demonstration of cytomegalovirus nucleic acids in the coronary arteries of transplanted hearts.

Cytomegalovirus (CMV) infection has been associated with the development of accelerated arteriosclerosis in heart transplant recipients. This association prompted the authors to examine, using in situ hybridization techniques, the coronary arteries of 19 patients who had received heart transplants for the presence of CMV nucleic acids. Two probes were employed on formalin-fixed paraffin-embedded tissues. The first was an S35-labeled nick translated probe derived from CMV DNA. CMV nucleic acids were identified in the arterial intima of 5 (45%) of 11 transplanted hearts examined with this probe. Hybridization to cells morphologically consistent with endothelial cells, lymphocytes, and smooth muscle cells was identified. Hybridization was not detected in any of the hearts when a control probe, a vector without CMV DNA, was employed. The second probe that was used was a tritium-labeled strand-specific ribo-probe derived from the immediate early (IE1) gene of CMV. Using this second probe, hybridization was detected in the coronary arteries of three of five hearts that were positive with the DNA probe, in one of the hearts that was negative with the DNA probe, and in three (38%) of eight additional transplanted hearts. The pattern of hybridization was the same as that seen with the DNA probe, and no hybridization was detected when a control sense probe for the IE1 gene of CMV was employed. These results suggest that CMV nucleic acids are present in the coronary arteries of heart transplant recipients.

Adolescent↗
PubMed1992

Virus-associated RNAs (VA-I and VA-II). An efficient target for the detection of adenovirus infections by in situ hybridization.

The identification of adenovirus in tissue can be difficult. In situ hybridization for adenovirus nucleic acids may aid in the demonstration of adenovirus infections. To develop a probe against adenovirus, a 978 bp fragment of DNA containing the VA-I, VA-II, and a portion of the L-1 regions of the adenovirus type 2 genome was cloned into the SK+ vector. These regions were selected because they are generally conserved among adenoviruses and are abundantly transcribed during the lytic cycle. Sense and antisense tritium or Digoxigenin-labeled riboprobes were generated using in vitro transcription and applied to formalin-fixed paraffin-embedded sections of HeLa cells infected with adenovirus type 2. Extensive in situ hybridization of the antisense riboprobe to HeLa cells with cytopathic changes was found. The number of cells to which the probe hybridized decreased proportionately with dilution of infected with noninfected cells. The control sense riboprobe showed only scattered breakthrough hybridization and in these cells hybridization was mainly located in the nucleus. Northern blot analysis of RNA from infected HeLa cells confirmed the in situ hybridization results. No hybridization was detected when cultured cells infected with herpes simplex virus, Epstein-Barr virus, cytomegalovirus, or human immunodeficiency virus were examined. Specific hybridization was detected in tissues obtained at autopsy from four patients with culture proven adenovirus infection. These observations suggest that this probe is useful in the diagnosis of adenovirus in formalin-fixed paraffin-embedded material.

Adenoviridae Infections↗
PubMed1992

Expression of retinoic acid receptor genes in developing rat livers and hepatoma cells.

The expression of retinoic acid receptor alpha, beta, and gamma mRNA was examined in developing rat livers and rat hepatoma-derived cell lines H-4-II-E, McA-RH 7777, and 8994 that represent different hepatocyte phenotypes. Northern blot hybridization demonstrated that all three receptor mRNAs were expressed in the fetal livers of different gestational ages, and the levels of expression increased significantly 3 to 4 weeks after birth. In the hepatoma cell lines, the expression pattern of retinoic acid receptor alpha and gamma mRNA did not correlate with the phenotype. In contrast, retinoic acid receptor beta mRNA was only detected in the adult phenotypic H-4-II-E cells but not in McA-RH 7777 and 8994 cells, which represent embryonic and fetal hepatocyte phenotypes, respectively. The levels of retinoic acid receptor beta mRNA in hepatoma cell lines were lower than adult rat liver. These data suggest that the increased expression of retinoic acid receptor beta gene is associated with differentiation or maturation of rat hepatocytes. The effect of retinoic acid on retinoic acid receptor gene expression was also studied in hepatoma cells. Retinoic acid did not regulate retinoic acid receptor gene expression in McA-RH 7777 and 8994 cells, and the retinoic acid receptor beta gene remained inactivated in these cells. However, Southern blot hybridization indicated that the gross structure of retinoic acid receptor beta gene was not altered during malignant transformation. In H-4-II-E cells, retinoic acid increased the expression of retinoic acid receptor beta and gamma gene. Because of the similarity between H-4-II-E cells and normal adult hepatocytes, this type of autoregulation may be a mechanism by which retinoic acid regulates its own effect in vivo.

Animals↗
PubMed1992

In situ localization of Epstein-Barr virus in thymic carcinoma.

Epstein-Barr virus (EBV) genome is associated with a variety of lymphoid and epithelial malignancies. EBV DNA has been detected in some cases of thymic carcinoma, but the cellular locus of the virus has never been defined. Detection of EBV has also been reported in normal thymus, thymic lymphoid hyperplasia, and thymoma by some investigators but not by others. In order to better define the association of the virus with benign and malignant thymic tissues and to characterize its cellular locus, we applied a recently developed in situ hybridization technique using a very abundant EBV transcript (EBER1) as target to a variety of thymic tissues. We detected expression of this transcript only in the malignant epithelial cells in one case of thymic lymphoepithelioma-like carcinoma. EBV expression was not detected in six other cases of thymic carcinoma, nor in tissue from 16 normal thymuses, 14 thymomas, and 10 thymic lymphoid hyperplasias.

Adult↗
PubMed1992

Localization of the human cytomegalovirus 2.7-kb major early beta-gene transcripts by RNA in situ hybridization in permissive and nonpermissive infections.

During the early phase of a human cytomegalovirus (HCMV) infection, the 2.7-kb early gene is by far the most abundantly transcribed RNA. Using strand-specific 32P or digoxigenin-labeled riboprobes derived from a subgenomic fragment of the HCMV Towne 2.7-kb early gene, we have performed Northern blot analysis and RNA in situ hybridization on human and mouse fibroblasts infected with HCMV and on 23 formalin-fixed paraffin-embedded sections of tissue obtained at autopsy. By Northern blot analysis, expression of the 2.7 kb early gene was found only in permissive infections. In contrast, specific hybridization was detected in both permissive and nonpermissive cells by RNA in situ hybridization. In nonpermissive cells, hybridization was weak and predominantly nuclear. In permissive cells, strong nuclear and cytoplasmic hybridization was noted. Specific hybridization to cells with and without cytopathic changes was detected with the anti-sense probe in CMV infected tissue obtained at autopsy. When the sense riboprobe was employed, no specific hybridization was found under nondenaturing conditions. These results suggest that in situ hybridization with a probe directed at the 2.7-kb early gene is an effective method of detecting both permissive and nonpermissive HCMV infections in different stages of infection and in localizing the expression of the major early gene in various cell types.

Animals↗
PubMed1992

[Bleeding secondary duodenal diverticulum: a rare late complication following nephrolithotomy].

Secondary duodenal diverticula are due primarily to traction upon that section from some other cause such as ulcer, cholecystitis and so forth. It accounts for 1.6 to 20% of all duodenal diverticula. Numerous reports of gastrointestinal hemorrhage from duodenal diverticula have appeared in the literature. But massive UGI bleeding due to secondary duodenal diverticulum, caused by nephrolithotomy, was a rare late complication. Here we present a case of a 63-year-old male patient who underwent a right side nephrolithotomy 10 and 8 years previously, then developed massive UGI bleeding suddenly. Pre-operative UGI series and gastroscopy showed chronic duodenal ulcer and duodenal diverticulum at second section where much blood clot was noted. In time, a successful operation was performed. This complication of secondary duodenal diverticulum was rare, so consideration regarding management and surgical approach was discussed.

Diverticulum↗
PubMed1991

HPV-16 viral transcripts in vulvar neoplasia: preliminary studies.

Specific human papillomavirus (HPV) types are strongly associated with intraepithelial neoplasia and invasive cancer of the cervix. In contrast, the role of HPVs in the pathogenesis of invasive carcinoma of the vulva is poorly understood. We have employed in situ hybridization for the detection of subgenomic transcripts in four vulvar specimens to elucidate the role of HPV type 16 in the development and progression of vulvar cancer. These analyses revealed that the transcripts of the E6-E7 region were more abundant than those of the L1-L2 region in vulvar neoplastic tissues. The transcripts from early and late region of HPV-16 continued to increase with the differentiation of the epithelial cells in both the warty and the basaloid types of vulvar precancerous lesions. This pattern persisted in invasive warty carcinoma but not in basaloid invasive carcinoma; the transcripts in basaloid carcinoma were distributed in an even and discrete pattern. In contrast to earlier studies, L1-L2-region transcripts, as well as viral capsid protein, were detected in focal areas of well-differentiated cells of invasive warty carcinoma. These findings suggest that expression of HPV-16 is regulated by the degree of cellular differentiation.

Carcinoma↗
PubMed1991

Effects of varying marijuana smoking profile on deposition of tar and absorption of CO and delta-9-THC.

We investigated the effects of previously observed differences in smoking technique for marijuana (M) versus tobacco (T) on the amount of inhaled tar, the percentage retention of inhaled tar in the lung, the pre- to postcigarette boost in blood carboxyhemoglobin (COHb) and in serum delta-9-tetrahydrocannabinol (THC concentrations), and psychophysiologic responses to THC (increased heart rate and subjective "high"). Ten healthy, habitual smokers of M were studied on 6 separate days. On each day, subjects smoked a single M cigarette (approximately 900 mg, 1.24% delta-9-THC) using one of 6 different smoking profiles typical for marijuana [puff volume (PV) approximately 70 ml; breathholding time, (BHT) 14-16 s] or tobacco (PV approximately 45 ml; BHT 4-5 s) or a combination of the two techniques (PV approximately 70 ml and BHT 4-5 s; or PV approximately 45 ml and BHT 14-16 s). Inhaled volume (1.5 liters), interpuff interval (30 s) and number of puffs (6) were all fixed, except that for the approximately 45-ml PV condition, the number of puffs was increased to 10 in 2 additional sessions to standardize the total amount of cigarette consumed to that of the approximately 70-ml PV condition. The longer BHT significantly increased both percent retention of tar in the lung and the pre- to postsmoking rise in blood COHb, serum THC and heart rate, independent of puff volume and number. In contrast, the larger PV had no significant influence on these variables for the same amount of cigarette consumed.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1991

Tar, CO and delta 9THC delivery from the 1st and 2nd halves of a marijuana cigarette.

Previous in vitro studies suggest that, with successive puffs from a marijuana cigarette, delta-9-THC becomes concentrated in the remaining uncombusted portion of the cigarette. These observations are consistent with the common practice of smoking marijuana cigarettes to a smaller butt length than that to which tobacco cigarettes are smoked. The purpose of the present study was to compare the delivery of delta-9-THC, as well as total insoluble smoke particulates (tar) and carbon monoxide, from the distal ("first") versus the proximal ("second") halves of a standard marijuana cigarette during "natural" smoking of marijuana. On 4 separate days, ten habitual marijuana users smoked nearly all or approximately 1/2 of a standard marijuana cigarette (83 mm length; 800-900 mg; 1.24% THC), as follows: day 1, "whole" cigarette (60 mm smoked, leaving a 23-mm butt); day 2, "first" half (first 30 mm); day 3, "second" half (second 30 mm) after the "first" half was presmoked with a syringe; and day 4, "second" half after the "first" half was excised. A previously described smoking apparatus (20) was used for measurement of puff volume and inhaled tar. Puff volume and number were allowed to vary spontaneously (provided that the specified length of cigarette was consumed), while inhaled volume (1.5 liters), breathholding time (14 s) and interpuff interval (30 s) were held constant. Blood samples were withdrawn prior to smoking and serially after completion of smoking for analysis of blood carboxyhemoglobin (COHb) and serum delta-9-THC. Heart rate was measured before and 5 min after smoking. Subjects rated their level of "high" 20 min after completion of smoking.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Monoxide↗
PubMed1991

Abundant expression of EBER1 small nuclear RNA in nasopharyngeal carcinoma. A morphologically distinctive target for detection of Epstein-Barr virus in formalin-fixed paraffin-embedded carcinoma specimens.

The highly restricted expression of the Epstein-Barr virus (EBV) genome in malignancy has limited the use of EBV detection methods applicable to formalin-fixed paraffin-embedded carcinoma specimens. In EBV-transformed lymphocytes very short nonprotein coding EBV transcripts (EBERs) are expressed in much higher abundance (10(7) copies per cell) than other EBV latency transcripts. Using a 3H riboprobe, the authors demonstrated EBER1 expression in NASOPHARYNGEAL CARCINOMAS (NPCs) as well as in parotid salivary gland. Recognition of EBER1 expression was facilitated by the intensity of hybridization and its characteristic morphology (nuclear with nucleolar sparing). EBER1 expression was not demonstrated in other epithelial malignancies arising from mucosal surfaces (oropharynx, uterine cervix) from which EBV shedding has been detected. Repeat study of the NPC specimens with digoxigenin-labeled probe yielded hybridization signal with subcellular morphologic detail and without background in a 12-hour procedure. Thus the EBER1 transcript is an appropriate target for in situ hybridization detection of EBV in formalin-fixed paraffin-embedded carcinoma specimens.

Carcinoma↗
PubMed1991

Insulinoma: a case report.

Insulinoma is a rare disease, which frequently causes hypoglycemic symptoms and signs or even shock. However, other diseases that produce similar symptoms and signs should firstly be ruled out. We describe a 63 years old male veteran who suffered from repeated episodes of seizure and conscious disturbance upon fasting, on and off for 8 years. Serial examinations led to the suspicion that this might be a case of insulinoma; the suspicion was later confirmed by pathologic examination after the tumor had been excised, and his problems disappeared. After six years, a follow-up examination showed that his condition was still stable.

Humans↗
PubMed1991

Management of penetrating abdominal injury.

We present the results of immediate exploratory laparotomies for penetrating abdominal injuries that were performed in the past five and half years. Thirty-eight cases (37 males and 1 female) were collected in this study, ranging in age from 17 to 74 years, with a mean of 36 years. Nine suffered from gunshot injuries and 29 from stab injuries. The negative exploratory laparotomy rate was 22.2%, the surgical complication rate was 18.4%, and the mortality rate was 5%. In this retrospective study, we conclude that: 1. Patients with injuries of the abdomen or unstable vital signs should be operated on immediately. 2. Peritonitis signs are not absolute indications of the need for emergent exploration. 3. For the stab injury patients with stable pre-operative vital signs, conservative treatment with simple closure of wounds is adequate. Frequent checks of vital signs and abdominal condition can possibly prevent unnecessary operations.

Abdominal Injuries↗
PubMed1990

Detection of EBV gene expression in Reed-Sternberg cells of Hodgkin's disease.

EBV DNA has been detected by Southern blot hybridization in 20-25% of Hodgkin's disease tumor specimens and localized to the Reed-Sternberg cells by in situ hybridization. In the present investigation we used a 3H-labelled EBER I anti-sense RNA for in situ hybridization of archival formalin-fixed paraffin-embedded Hodgkin's disease specimens previously shown by Southern Blot hybridization to be EBV-positive. In 6 of 8 specimens neoplastic cells showed an intense signal in virtually all of the tumor cells. The background lymphocytes, eosinophils, plasma cells and histiocytes did not demonstrate significant hybridization. In each case hybridization tended to spare the nucleoli. Hybridization was detected in specimens with histologies of mixed cellularity and nodular sclerosis. The intensity of signal relative to background is better than that in previous studies utilizing 35S-labelled large internal repeat probes for EBV in Reed-Sternberg cells. The exposure time is one week in contrast to the 4-5 weeks reported by others for detection of EBV in Hodgkin's disease. Both increased relative intensity and shorter exposure requirements may be attributed to the very high number of EBER transcripts in the target cells. The demonstration that EBER I is expressed is consistent with a role for EBV in growth regulation of Reed-Sternberg cells and suggests that the virus is not merely a silent passenger in Hodgkin's disease.

Blotting, Southern↗
PubMed1990

Effects of oral cetirizine, a selective H1 antagonist, on allergen- and exercise-induced bronchoconstriction in subjects with asthma.

The protective efficacy of oral cetirizine, a selective and potent H1-receptor antagonist, against the immediate bronchoconstrictive response to allergen inhalation and exercise challenge was evaluated in 16 subjects with stable, predominantly mild asthma. The subjects underwent double-blind, crossover pretreatments in randomized order in two separate protocols with (1) three daily oral doses of 20 mg of cetirizine and placebo, followed by allergen inhalation, and (2) single oral doses of cetirizine (5, 10, and 20 mg), albuterol (4 mg), and placebo, followed by exercise with cold-air inhalation. Cetirizine failed to decrease bronchial sensitivity to inhaled allergen in eight of 10 subjects. Neither cetirizine nor albuterol uniformly inhibited exercise-induced bronchoconstriction. Serum concentrations of cetirizine were consistent with systemic H1-blocking activity. Modest bronchodilation occurred after administration of cetirizine and albuterol before exercise but not after the third dose of cetirizine in the allergen protocol. One subject developed moderate drowsiness during multiple dosing with cetirizine. Thus, cetirizine, in the doses studied, is not uniformly effective in preventing allergen- or exercise-induced bronchoconstriction. Histamine is one of many mediators participating in immediate asthmatic responses, and selective H1 antagonists do not completely block these airway events. However, cetirizine may still clinically benefit some patients with asthma, such as patients with allergic rhinitis or urticaria.

Administration, Oral↗
PubMed1990

[Retrospective study of Salmonella gastroenteritis in infants].

UNLABELLED: Sixty-four cases of Salmonellosis were retrospectively analyzed in Jan. 1985 to Dec. 1988 at the department of pediatrics, Veteran General Hospital, Taipei. Most of the cases (78%) occurred between May and October, the most common pathogenic organism isolated was B salmonella group (65.6%). Antibiotic susceptibility to ampicillin revealed remarkably decrease from 75% (1985) down to 11.7% (1988) and the most sensitive antibiotic agent was ceftriaxone (98.3%). Blood culture were obtained in 42 cases and patients with salmonella bacteremia were found in 10 cases (23.8%). Five of 17 patients under 3 month old showed positive blood culture. Four of 5 bacteremic patients were complicated individually with convulsion, failure to thrive, chronic diarrhea and one case expired. Four of 33 patients between 3 month and 1 year were bacteremic. Two of 4 bacteremic patients were respectively complicated with meningitis and hip-joint arthritis. The average duration of salmonella shedding was 37.5 days (range 4-180 days). IN CONCLUSION: 1. Salmonellosis hasn't decreased in the past 4 years and the resistance to ampicillin and chloramphenicol has increased. 2. Young infants are at particular risk for bacteremia and focal complication, so if salmonellosis is suspected in infants under 3 month old, blood culture should be obtained and proper antibiotic therapy should be given.

Female↗