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Biomedical subjects

T Kuo

Publications and source records attributed to T Kuo.

At least 37 records · Page 2Linked to original sources

The role of activation of the sympathetic nervous system in the central pressor action of calcitonin gene-related peptide in conscious rats.

The effects of intracerebroventricular (i.c.v.) administration of calcitonin gene-related (CGRP) on blood pressure and heart rate (HR), and the underlying mechanisms were studied in conscious rats. CGRP (0.1-3.0 nmol i.c.v.) increased mean arterial blood pressure (MABP) and HR. CGRP (3.0 nmol i.c.v.) also significantly increased both plasma norepinephrine and epinephrine concentrations. Pretreatment with 16.5 nmol i.c.v. CGRP(8-37), a specific CGRP receptor antagonist, significantly inhibited the i.c.v. CGRP (1.0 nmol)-induced increases in MABP and HR. Phenoxybenzamine inhibited the i.c.v. CGRP-induced increase in MABP, while propranolol suppressed the tachycardiac response to i.c.v. CGRP. Chemical sympathectomy by 6-hydroxydopamine inhibited the increases in MABP and HR produced by i.c.v. CGRP. These results suggest that the central pressor and tachycardiac effects of i.c.v. CGRP are mediated by catecholamine release due to stimulation of sympathetic nervous system activity, possibly via specific CGRP receptors in the central nervous system.

Animals↗

A quantitative evaluation of gloves used with non-powered hand tools in routine maintenance tasks.

Non-powered hand tools are a major means of carrying out routine maintenance and repair activities. The use of gloves in such situations is essential in order to protect the hands from potential injuries. Together, the gloves and hand tools accomplish the task by transmitting the muscle force on to the workpiece. Several studies have reported that the capability of hands to exert force/torque is severely influenced by the use of gloves. The use of gloves could also lead to a cumulative trauma disorder, rapid onset of muscular fatigue, etc. Most previous studies have focused on determining the influence of gloves on grip strength or push/pull forces one would exert while using devices such as knives. The purpose of this study was to determine the influence of a variety of commercially available gloves on the force/torque exertion capability of workers with wrenches and screwdrivers that are commonly used in performing routine maintenance and repairs. Nineteen males participated in the study and, using seven different hand tools and nine varieties of commercial gloves, exerted peak volitional torques on a simulated workpiece. The peak torque and electromyogram of flexor and extensor muscles were recorded. The results indicated that muscle activity did not differ significantly between the glove and no-glove conditions and the peak torque exertion capability of individuals generally increased with gloves. The magnitude of torque exerted on the workpiece was different for different gloves. The results also contradict some of the previously reported findings.

Adult↗

Evaluation and management of sialorrhea of pregnancy with concomitant hyperemesis.

This article describes two gravid patients who presented with first-trimester sialorrhea and hyperemesis. Although excessive salivation, especially when accompanied by protracted nausea and vomiting, is an unusual occurrence, it can have serious consequences for both the mother and fetus when left untreated. Initially, phenothiazine was prescribed and later belladonna alkaloid was added separately to the two treatment regimens. In order to successfully treat the excessive salivation, it was necessary to control the nausea and vomiting. Eradication of sialorrhea and hyperemesis were effected 10 days posttreatment. For both patients, pregnancy, delivery, and postpartum intervals proceeded uneventfully. Mothers and infants remain in good health 2 years posttreatment.

Adult↗

Inappropriate breast secretions of possible bacterial etiology in the parous nonpuerperal female.

This article presents two cases of spontaneous green breast secretions of parous nonpuerperal patients. To understand the nature of these secretions, bacterial evaluations and subsequent treatment were undertaken. Case 1 culture and sensitivity studies from breast secretions were commenced within 24 hours yielding an isolate identified as Staphylococcus epidermidis, with sensitivity to cephalothin, erythromycin, and tetracycline but resistant to penicillin. Cephalothin, 500 mg four times a day for 10 days, followed by erythromycin 100 mg twice a day for 10 days and doxycycline 100 mg twice a day for 10 days, did not alter the breast secretions. Four weeks later, ciprofloxacin HCI 500 mg twice a day for 6 weeks caused a 50% decrement in breast secretion at 4 weeks but increased clinical depression. At 6 weeks, no evidence of breast secretions persisted. Mental depression decreased within 2 weeks postciprofloxacin treatment. In Case 2, a total of 35 minutes elapsed between sample collection and initiation of culture and sensitivity studies. Moraxella osloensis was identified and found sensitive to ampicillin and tetracycline but resistant to trimethoprim. Ampicillin 500 mg four times a day for 10 days and doxycycline 100 mg twice a day by mouth for 10 days were administered at 2-week intervals with no effect on breast discharge. After 4 weeks of treatment failure, ciprofloxacin HCI 500 mg twice a day for 6 weeks caused a 50% decrease in discharge at 2 weeks and total elimination at 6 weeks. Lethargy during treatment ceased with termination of therapy. These results support the importance of bacterial evaluation of breast secretions with subsequent antibiotic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Acute effect of percutaneous transluminal mitral commissurotomy on QT interval: possible role of afterload in contraction-excitation feedback.

Percutaneous balloon valvuloplasty for pulmonary or aortic stenosis results in QT prolongation, a finding supporting the presence of contraction-excitation feedback in man. Though afterload reduction alters the QT interval, the effect of changes in preload on ventricular repolarization is yet unknown. To test whether diastolic stretch modified ventricular repolarization, the change in the QT interval was determined in 15 patients who underwent percutaneous transluminal mitral commissurotomy (PTMC) for mitral stenosis. After successful PTMC, the QT interval was prolonged in five, shortened in two, and was unchanged in eight patients, but the mean QT interval in 15 patients did not change (406 +/- 31 msec versus 412 +/- 40 msec, p = NS). However, linear regression analysis revealed a strong correlation between changes in the QT interval and those in systemic vascular resistance (r = -0.83, p less than 0.01). These data indicated that changes in the QT interval after PTMC were small compared with those seen with valvuloplasty for pulmonary or aortic stenosis, and were dependent on afterload but not on preload.

Adult↗

Relationship between expression of P-glycoprotein and efficacy of trifluoperazine in multidrug-resistant cells.

Tumor cell resistance due to enhanced efflux of drugs with diverse structures and/or mechanisms of action is termed multidrug resistance (MDR), and modulation of the MDR phenotype by calcium blockers or calmodulin inhibitors is suggested to involve P-glycoprotein. In drug-sensitive (S) and 5-fold doxorubicin (DOX)-resistant (R0) L1210 mouse leukemia cells, no obvious differences in mdr mRNA or P-glycoprotein expression or alterations in cellular uptake, retention, or cytotoxicity of vincristine (VCR) were observed. However, in the 10-fold (R1) and 40-fold (R2) DOX-resistant sublines, expression of P-glycoprotein was correlated with the level of resistance (R2 greater than R1). An RNase protection assay revealed that elevated levels of mdr1 and mdr2 mRNA were detected in R1 and R2 cells, with an additional increase in mdr3 mRNA in the R2 subline. Further, in the R1 and R2 sublines, no VCR dose-dependent cytotoxicity was apparent, and cell kill of greater than 40% was not achievable following a 3-hr drug exposure. Cellular uptake and retention of VCR were 2- to 4-fold lower in the R1 and R2 sublines, compared with similarly treated S or R0 cells. Potentiation of VCR cytotoxicity by a noncytotoxic concentration of 5 microM trifluoperazine (TFP) was greater than 2-fold in S and R0 cells and less than 1.3-fold in the R1 and R2 sublines. Modulation of VCR uptake by 5 microM TFP in the S and R0 cells was 2-fold and it was 4- to 7-fold in the R1 and R2 sublines. The presence of 5 microM TFP, by competing for efflux, enhanced VCR retention 1.5-fold in S and R0 cells and 2- to 4-fold in the R1 and R2 sublines. In contrast to these results with VCR, dose-dependent cytotoxicity of DOX was apparent in all the resistant sublines, and modulation of DOX cytotoxicity by 5 microM TFP was dependent on the level of resistance. Cellular accumulation of DOX was 20 and 50% lower in the R1 and R2 sublines, respectively, compared with similarly treated S or R0 cells. Marked increases (greater than 1.5-fold) in cellular accumulation of DOX by TFP were apparent only in the R2 subline. Results suggest that a relationship between overexpression of P-glycoprotein isoforms and their role in affecting cellular drug levels and consequent cytotoxicity in MDR L1210 cells determines resistance to VCR but not DOX.(ABSTRACT TRUNCATED AT 400 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Roseola infantum caused by human herpesvirus-6: report of 7 cases with emphasis on complications.

Roseola infantum is not an uncommon disease in children. The etiology was not known until 1988 when Yamanishi et al in Japan first demonstrated that human herpesvirus-6 (HHV-6) was the causative agent. In the fall of 1989, we began to study the role of HHV-6 in roseola infantum in Taiwan. A total of 7 cases of suspected roseola infantum were studied and all were proven to have primary HHV-6 infections. Six were classic cases of roseola infantum, while one had only fever without the rash. Two cases developed complications; one had leukopenia and thrombocytopenia and the other had aseptic meningitis and mononucleosis. This is the first report to substantiate that HHV-6 is an important cause of roseola infantum in Taiwan, and that the virus could cause meningitis and thrombocytopenia.

Exanthema Subitum↗

Immunogenicity of primary DPT vaccination.

Children have been given the diphtheria and tetanus toxoid and pertussis vaccine (DPT) in Taiwan for more than 30 years. Yet, the antibody responses to DPT have not been investigated in recent years. Two new antigens of Bordetella pertussis, pertussis toxin and filamentous hemagglutinin, were identified in B. pertussis several years ago and became the constituents of a new type of pertussis vaccine, acellular vaccine. This study was undertaken to test the antibody responses toward diphtheria, tetanus, and pertussis with conventional methods as well as new methods to detect antibodies against pertussis toxin and filamentous hemagglutinin. A total of 104 children, at ages between 12 and 23 months, who had received 3 doses of DPT vaccine were tested. Almost all (99%) of them possessed diphtheria and tetanus antitoxin concentrations above the protective level. With the criteria derived from an animal study, at least 85% of the vaccinees might have protective antibodies against pertussis. This serological study showed the effectiveness of the present DPT vaccine in Taiwan. If a new DPT vaccine is to be introduced into Taiwan, it should have at least the same immunogenicity as the present vaccine.

Antibodies, Viral↗

High-resolution mapping of DNase I hypersensitive site in the chicken beta-tubulin gene transfected into monkey cells.

In this report, we describe a method for high-resolution mapping of a nuclease hypersensitive site (HS) at the promoter region of the chicken beta 2-tubulin gene transfected into monkey Cos-7 cells. Using the indirect end-labeling method of Wu, a tissue-specific nuclease HS was located initially approximately 100 base pairs upstream of the transcription start site. For high-resolution mapping of the HS in the transfected DNA, a DNA fragment of about 400 base pairs containing the promoter region of the beta 2 gene was subcloned into M13 phage. A single-stranded DNA probe with a defined restriction enzyme cleavage site at one end was prepared from the M13 phage DNA template. The single-stranded probe and the restriction enzyme-digested DNA, prepared from nuclease-digested nuclei from transfected cells, were sequentially annealed back to the template. After ligation between the probe and the transfected DNA, the HS was determined by DNA sequencing gel electrophoresis. This method permits determination of the 3' boundary of the HS with precision at the single-nucleotide level. We mapped a major HS at -107 nucleotides of the beta 2-tubulin gene, where a CACCC-like sequence is present. The application of this method in determining HS is discussed.

Animals↗

Specific gene amplification associated with consistent chromosomal abnormality in independently established multidrug-resistant Chinese hamster ovary cells.

Multidrug-resistant (MDR) Chinese hamster ovary (CHO) cell lines were established by selection for resistance to the toxicities of vinblastine (VB) and Adriamycin (AD) in progressively increasing drug concentrations. These cell lines have amplified the DNA sequence that has previously been shown to be amplified in another MDR CHO cell line which was selected with vincristine (VC). An overproduced 4.5 kb mRNA was detected in these MDR cell lines. We report here that the levels of DNA amplification and the 4.5 kb transcript do not correlate with the levels of drug resistance, suggesting that either translational control for the expression of the amplified gene is involved or multiple genes are participating in conferring drug resistance in these cell lines. The amplified DNA sequence was used as a probe and localized by in situ hybridization to chromosome 1q 26-28 (middle portion of the long arm) in the drug-sensitive CHO line, but proximal to the telomere of chromosome 1q in both VB- and AD-selected MDR cell lines. This is consistent with results that have been previously reported for the VC-selected MDR cell lines. Cytogenetic analyses revealed abnormal chromosomal banding patterns or homogeneously staining regions (HSR) between 1q 26-28 and the 1q ter in these independently established MDR lines. These results, taken together, suggest that chromosomal rearrangements leading to gene translocation have consistently accompanied gene amplification in these MDR cell lines. The mechanisms of translocation and its implication in multidrug resistance in these cell lines are discussed.

Animals↗

DNA hybridization for human papillomavirus (HPV) in cervical lesions. Relationship of the presence of various viral subtypes to expression of HPV structural proteins, involucrin, and carcinoembryonic antigen.

We studied cervical tissue from 20 patients with a variety of condylomatous, preneoplastic, and neoplastic lesions to detect various subtypes of human papillomavirus (HPV) at the molecular level by DNA hybridization. In addition, mirror image biopsy specimens were studied by an immunoperoxidase technique for the presence of HPV structural antigens, carcinoembryonic antigen (CEA), and involucrin, as markers of disturbed maturation and/or neoplasia. Of the 20 patients studied, we were able to demonstrate the presence of either HPV 16 or 18, or both, in three of seven squamous carcinomas tested, and three of five dysplasias. Interestingly, two cases of squamous carcinoma and one moderate dysplasia demonstrated HPV types 6 and 11 concurrently with HPV 16 and/or 18. Four of six condylomas showed HPV subtypes 6/11, and only one condyloma showed weak hybridization with HPV 18. Human papillomavirus structural antigen was seen in three of eight condylomas, and three of five dysplasias, but not in any carcinoma. All condylomas showed intense staining for involucrin in full-thickness of the epithelium, but the high-grade dysplasias and carcinomas showed only focal or absence of staining for involucrin. Carcinoembryonic antigen was expressed in 50% of the carcinomas with a pattern similar to that seen with involucrin, but did not correlate with any particular subtype of HPV. The molecular hybridization method seems to be superior for the detection of HPV lesions, and possibly for the prediction of their biologic behavior.

Antigens, Viral↗

DNA amplification in multidrug, cross-resistant Chinese hamster ovary cells: molecular characterization and cytogenetic localization of the amplified DNA.

Vincristine-resistant (VCR) Chinese hamster ovary (CHO) cells have been established by stepwise selection in increasing concentrations of vincristine. These cells exhibit multidrug cross-resistance to a number of drugs that have no structural or functional similarities. Cytogenetic analyses of resistant cells revealed the presence of double minutes and expanded chromosomal segments, thus implicating gene amplification as a possible mechanism of resistance. An amplified DNA segment isolated from other multidrug cross-resistant CHO cell lines (Roninson, I. B., H. T. Abelson, D. E. Housman, N. Howell, and A. Varshavsky, 1984, Nature (Lond.), 309:626-628) is also amplified in our VCR lines. This DNA segment was used as a probe to screen a cosmid library of VCR genomic DNA, and overlapping clones were retrieved. All of these segments, totaling approximately 45 kilobases (kb), were amplified in VCR cells. Using in situ hybridization, we localized the amplification domain to the long arm of CHO chromosome 1 or Z1. Northern hybridization analysis revealed that a 4.3-kb mRNA was encoded by this amplified DNA domain and was over-produced in the VCR cells. Suggestions for the involvement of these amplified DNA segments in the acquisition of multidrug cross-resistance in animal cells are also presented.

Animals↗

The expression and chromatin structure of the chicken glyceraldehyde-3-phosphate dehydrogenase gene in mouse cells.

Chicken glyceraldehyde-3-phosphate dehydrogenase gene (GAPD) and thymidine kinase gene (TK) were co-transfected into mouse LMTK- cells by the calcium phosphate precipitation technique. Four of the eight hypoxanthine/aminopterin/thymidine-containing medium-resistant, TK+ transfectants were shown to produce different amounts of chicken glyceraldehyde-3-phosphate dehydrogenase by zymogram analysis. Subcloning and further analysis revealed that the chicken GAPD was stably inherited and that its enzyme subunits randomly combined with mouse subunits in heterotetramers. Although the contribution of chicken enzyme varied from approximately 30 to approximately 90% of the total glyceraldehyde-3-phosphate dehydrogenase activity with a proportional increase in total activity in the different subclones, it did not appear to affect the expression of mouse endogenous glycolytic enzymes since there was no distinct change in the levels of either mouse glyceraldehyde-3-phosphate dehydrogenase mRNA nor mouse phosphoglycerate kinase enzyme activity. The levels of chicken GAPD copy number, mRNA, and enzyme apparently were generally correlated in the different subclones, suggesting that the chicken GAPD in the mouse cells were expressed constitutively. In situ hybridization revealed that the transfected genes were integrated into mouse chromosomes in one cluster, and the locations of these clusters were different in different clones. Chromatin structure analyses of the chicken GAPD in four different transfectants revealed three DNase I-hypersensitive sites located around 0.2, 2.0, and 3.4 kilobases upstream from the 5' side of the gene. These sites are also present in the same locations in chicken lymphoblastoid cells (Kuo, M. T., Iyer, B., and Schwartz, R. J. (1982) Nucleic Acids Res 10, 4565-4579), indicating the dominant transmission of DNase I-hypersensitive cleavage sites in the transfected gene.

Animals↗

Giant intracranial Masson's hemangioma. Report of a fatal case.

A giant intracranial Masson's hemangioma (intravascular papillary endothelial hyperplasia) arising from the meninges occurred in an infant. The outcome was fatal. The associated thrombocytopenia linked Masson's hemangioma to the Kasabach-Merritt syndrome.

Angiography↗