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Biomedical subjects

C H Yang

Publications and source records attributed to C H Yang.

At least 235 records · Page 13Linked to original sources
PubMed1991

Localization of one gene for tuberous sclerosis within 9q32-9q34, and further evidence for heterogeneity.

Tuberous sclerosis (TSC) is an autosomal dominant disorder with both neurological and cutaneous manifestations often resulting in significant disability. Although it has been studied clinically and biochemically for many years, the underlying pathophysiology remains unknown. Genetic linkage analysis provides an alternative strategy for understanding the genetic etiology of this disease. Genetic linkage of a gene for TSC to loci in 9q32-9q34 has been reported but has not been a universal finding, since absence of linkage to 9q loci, as well as linkage to loci on 11q, have also been reported. We present here data on 22 families (21 previously unreported) segregating TSC. Our results strongly support a TSC locus in the 9q32-34 region for approximately one-third of families and provide significant evidence for genetic heterogeneity. Application of newly described highly polymorphic dinucleotide repeat marker loci in TSC greatly enhanced the informativeness of our pedigrees and was vital for detecting the heterogeneity. No clear evidence of linkage to chromosome 11q22 markers was found, suggesting that a still unidentified TSC locus elsewhere in the genome may account for the majority of TSC families.

Chromosomes, Human, Pair 9↗
PubMed1991

[Berberine-electrochemical detector for the determination of berberine-type alkaloids in various Chinese patent medicines by flow injection analysis].

A description is given for the preparation of flow through sensor and of the incorporation of the sensor into a flow injection analysis system. The parameters affecting the measurement are discussed. An accurate, convenient and rapid method is proposed for the determination of berberine-type alkaloids in various Chinese patent medicines (Coptis chinensis Franch., Phellodendron chinesis Schneid., xianglian wan, zuojin wan, ermiao wan and sanmiao wan). The slope is 54-60 mV/decade over the concentration range of 10(-3)-3 x 10(-6) mol/L berberine at pH 2-9.5. Direct potentiometry determination of berberine in various samples showed an average recovery of 99.5-103.5% and a relative standard deviation of 1.3-3.5% at a sampling rate of 120/h.

Berberine↗
PubMed1990

Time spent and satisfaction of new out-patients in Department of Internal Medicine. Kaohsiung Medical College Hospital.

To assess the time spent and the degree of satisfaction of new clinic patients, one hundred and nine new out-patients from the Internal Medicine Clinic of Kaohsiung Medical College Hospital were studied from January 30th to February 6th, 1985. Both accurate field recording and telephone interviews concerning the time spent for each procedure and satisfaction with the medical personnel and expense in their first visits were carried out. The total time spent was 152 +/- 65 minutes (mean +/- SD) from questionnaire and 126 +/- 56 minutes from field recording. According to field recording, time spent in waiting for registration was 39.8 +/- 42.9 minutes. Most (55%) of study patients spent more than one hour in waiting for consultation. The time spent in waiting for filling prescription was 17 +/- 6 minutes. The accessibility of the paramedical examination units was good. The degree of satisfaction was measured by a five point rating scale for series of questions. The response were "very satisfied" or "satisfied" with professional services but not medical expense and cashier attitude. According to our results, some of our attempts to innovate service have been done including an appointment system, colored directional arrowheads, and changing our schedule to opening 30 minutes earlier.

Appointments and Schedules↗
PubMed1990

Bilateral Warthin's tumors in a Chinese--literature review and case report.

Warthin's tumor is an unusual benign salivary gland tumor. It is predominantly found in Caucasians and is rare in non-Caucasians. The chief affected area of the tumor is the parotid gland. Of all salivary gland neoplasms, Warthin's tumor is the only lesion which is truly multicentric so it may have a second primary lesion, not a recurrence. The peak incidence is in the sixth decade of life. In sexual distribution, there is a male predominance but the incidence of female is progressively increasing. According to Lemelas's study, the increase in female incidence may relate to the increasing population of cigarette smoking of women. Bilateral parotid gland involvement is uncommon. The chief treatment of the tumor is surgical excision. The surgical methods include enucleation, superficial parotidectomy, total parotidectomy. It is very important to protect the facial nerves from injury during surgery. In this paper, we report a case of bilateral metachronous Warthin's tumors with cystic degeneration of parotid glands in a Chinese. Other than literature review and case report, four different methods to protect facial nerves from injury were briefly described.

Adenolymphoma↗
PubMed1990

[Construction and application of atropine flow-through sensor in flow injection analysis].

A new kind of flow-through sensor for atropine has been studied. It exhibits Nernstian response for atropine with a slope of 54 +/- 1 mV/decade over the concentration range of 0.02-200 mmol/L at pH 5-8. The sensitivity coefficients of common compounds were determined. Only bromo-geramine, clonidine, strychnine and amantadine showed remarkable interference. Direct potentiometry for determination of atropine showed an average recovery of 99.2% and a relative standard deviation of 1.3%. It has been used in flow injection analysis (FIA) of atropine, anisodamine and scopolamine and belladonna preparations. Rate of analysis of as high as 60-100 samples/h was achieved.

Atropa belladonna↗
PubMed1989

Higher order structure is present in the yeast nucleus: autoantibody probes demonstrate that the nucleolus lies opposite the spindle pole body.

A panel of sera from 892 autoimmune patients was screened by indirect immunofluorescence on mammalian cells. Seventy-three sera were identified that recognize the nucleolus. Three of these sera appear to stain the nucleolus in yeast, suggesting that they recognize highly conserved antigens. These three sera also immunoprecipitate mammalian U3 snRNA-containing particles, which reside in the nucleolus and have been implicated in rRNA processing. Double immunofluorescence experiments with anti-nucleolus and anti-tubulin antibodies revealed a novel form of non-random nuclear organization in yeast. The spindle pole body and the nucleolus-both of which are associated with the nuclear envelope-preferentially localize at opposite ends of the nucleus. Organization of these and other components into specific regions of the nucleus may be important for optimizing their proper function.

Autoantibodies↗
PubMed1989

Keratoconjunctivitis sicca with associated secondary uveitis elicited in rats after systemic xylazine/ketamine anesthesia.

The systemic administration of an anesthetic dosage of a combination of xylazine and ketamine hydrochloride produced an acute exposure keratopathy which progressed into a syndrome resembling keratoconjunctivitis sicca. Within a few minutes corneal changes occurred that were characterized by viscous mucus, loss of corneal luster and dryness. Other acute but transient changes included development of cataracts, mydriasis and proptosis. Progressive changes were observed in the cornea within 4 days which lasted at least 8 weeks in some cases, and included punctate epithelial keratopathy progressing to devitalized or keratinized epithelial plaques. Polymorphonuclear cell infiltration of the corneal stroma associated with plaques occurred. Epithelial denudation and neovascularization of the cornea, dilation and engorgement of iridial blood vessels, as well as flare in the anterior chamber were also seen. The ocular lesions induced by xylazine/ketamine should be considered carefully when designing or interpreting research on the anterior segment. Ketamine hydrochloride with sodium pentobarbital produced excellent anesthesia without any significant ocular side-effects and may be preferred in many instances.

Animals↗
PubMed1989

Differences between mature ovarian and oviductal oocytes: a study using the golden hamster.

To investigate whether mature ovarian oocytes are physiologically identical with recently ovulated oocytes, hamster oocytes collected from ovaries approximately 1 h before ovulation were compared with the oocytes which had been in the oviduct for 3-4 h. Although these two groups of oocytes were at the metaphase of the second meiosis, there were quantitative differences between the two with respect to (i) sensitivity of cumulus matrix to hyaluronidase and spermatozoa (oviductal greater than ovarian), (ii) size of the perivitelline space (oviductal greater than ovarian), (iii) viscosity of the ooplasm (ovarian greater than oviductal), (iv) responsiveness to Ca2+-ionophore (oviductal greater than ovarian), and (v) time needed in completing meiosis (ovarian greater than oviductal). The most prominent difference was found in the zona pellucida. The zona of the oviductal oocyte was 'heterogeneous' in its optical density and had a stronger acrosome-reaction-inducing ability than that of the ovarian oocyte. When cultured in artificial media (e.g. F-10 medium with serum) for 4 h, the ooplasm of ovarian oocytes became like that of oviductal oocytes. However, their zonae remained unchanged. Zonae of ovarian oocytes became like those of oviductal oocytes only when they were exposed to ampullary and/or isthmic fluids. The zona-altering factors in the oviductal fluid (oviductal glycoproteins), which are apparently integrated into the native zona, may act to enhance the various functions of the zona.

Acrosome↗
PubMed1989

Morphology and fertilizability of zona-free hamster eggs separated into halves and quarters by centrifugation.

When mature hamster eggs were freed from their zonae pellucidae and centrifuged in a Percoll gradient, each egg was separated into a light half and a heavy half. Chromosomes remained in their original position during centrifugation, resulting in the production of light and heavy halves with and without chromosomes. When the eggs were treated with cytochalasin D (CD) and then centrifuged, the chromosomes moved to the centripetal pole and were extruded rapidly before each egg separated into halves or fragments. In the eggs without CD treatment, the density of cortical granules was reduced in the centripetal region of the egg. In those treated with CD, the density of the granules was reduced in both centripetal and centrifugal regions of the egg. Both light and heavy halves were fertilizable. There was, however, a notable difference between light and heavy halves. Most of the heavy halves supported development of sperm nuclei into pronuclei, whereas only few of light halves could do so, suggesting that most of light halves were lacking or deficient in materials necessary for the development of a sperm (male) pronucleus. When the light and heavy halves were centrifuged further, each separated into two quarters. The lightest quarter, which was almost totally devoid of organelles, was buoyant and very fragile. Spermatozoa could fuse with it, but the incidence of the fusion was low. In this quarter, the sperm nucleus could decondense, but could not develop into a pronucleus. This was in marked contrast with other three quarters in which sperm nuclei could develop into well-formed pronuclei.

Animals↗
PubMed1989

A comprehensive study of immunological abnormalities in Korean hemophiliacs.

To determine laboratory evidence suggesting immunological abnormalities in persons with hemophilia, we evaluated the immunological status of 75 Korean hemophiliacs, seronegative for human immunodeficiency virus (HIV) antibodies, who have been treated only with Korean factor VIII concentrates. From this study, it was shown that Korean hemophiliacs had decreased CD4 levels, increased CD8 levels, and decreased CD4:CD8 ratios. Diminished lymphocyte response to the mitogens, phytohemagglutinin and concanavalin A, and decreased natural killer cell activity were observed in the hemophiliacs. In addition, production of interleukin-II in the hemophiliacs was lower than in the healthy controls. The percentage of B lymphocytes was significantly reduced but the serum levels of immunoglobulin (Ig) G were elevated. However, the serum Ig A and Ig M levels were normal. This study demonstrated a high frequency of immunological abnormalities in HIV antibody negative Korean hemophiliacs treated only with domestic factor VIII concentrates.

Adolescent↗
PubMed1988

Further studies on a novel class of genetic variants of the L1210 cell with increased folate analogue transport inward. Transport properties of a new variant, evidence for increased levels of a specific transport protein, and its partial characterization following affinity labeling.

Studies are reported on the characterization of a new isolate within a novel class of variants of the L1210 cell exhibiting markedly increased transport inward of folate analogues. This variant (L1210/R83), which was selected in the presence of the antifolate metoprine, exhibited a 40-fold increase in [3H]aminopterin influx compared to parental cells and a modest (4-5-fold) increase in [3H]aminopterin efflux. The increase in influx was associated with a comparable increase in influx Vmax for the one-carbon, reduced folate transport system and the same increase in the amount of specific binding of [3H]aminopterin on the cell surface. Values for influx Km for [3H]aminopterin and specificity for various folate structures were unchanged. The alteration in influx Vmax and more rapid efflux accounted for the different level of intracellular exchangeable level of drug at steady state in this variant compared with parental L1210 cells. Otherwise, membrane potential was unchanged. The N-hydroxysuccinimide ester of [3H]aminopterin was used to covalently label the specific binding protein for folate compounds in the plasma membrane of variant and parental L1210 cells. Incorporation of label into this protein was stable under a variety of conditions and accounted for 97 and 52% of total cellular labeling, respectively, for membrane derived from R83 and parental L1210 cells at a reagent concentration of 20 nM. Specific affinity labeling on the surface of parental and variant cells was decreased in the presence of aminopterin, methotrexate, or 5-formyltetrahydrofolate, but not in the presence of folic acid. Also, [3H]aminopterin influx in these cells was inhibited by the N-hydroxysuccinimide ester of aminopterin or methotrexate, but not the N-hydroxysuccinimide ester of folic acid. These findings, in addition to the increased affinity labeling of this variant, which corresponds to the increase in influx of [3H] aminopterin also seen, appears to identify the affinity labeled protein as a component of the "classical" one-carbon, reduced folate transport system in these cells. The affinity labeled protein from each cell type was solubilized in sodium dodecyl sulfate or extracted in detergent in the presence of proteinase inhibitors and was found to elute from Sephacryl S-300 and migrate during sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single peak of Mr = 45,000-48,000. Recovery of labeled binding protein in these fractions from R83 variant cells was approximately 40 times greater than that from parental cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Affinity Labels↗
PubMed1988

Altered molecular properties of tubulin in a multidrug-resistant variant of Chinese hamster cells selected for resistance to vinca alkaloids.

The basis for the markedly altered intracellular binding of [3H]vincristine in a multidrug-resistant variant (DC-3F/VCRd-5L) of Chinese hamster lung cells (DC-3F) was investigated. Binding of [3H]vincristine by protein in cytosol derived from each cell type exhibited a differing requirement for GTP in MgCl2 containing buffer of low-ionic strength. Binding of [3H]vincristine occurred to cytosolic protein derived from both variant and parental DC-3F cells, but after removal of GTP, binding only occurred to cytosolic protein from parental cells regardless of the presence of added GTP. Although binding by cytosolic protein from parental DC-3F cells did not require GTP, the addition of 0.1 mM GTP increased by two-fold the rate and extent of binding. When cytosol from variant and parental DC-3F cells was incubated with low concentrations of [3H]vincristine in high-ionic strength buffer and analyzed by molecular-sieve HPLC, most of the protein binding [3H]vincristine in parentally derived cytosol eluted as Mr 110,000-115,000 daltons, corresponding to that for dimeric tubulin. The same binding species was not detected in cytosol derived from variant cells. However, these same fractions derived with both parental and variant cytosols contained tubulin as shown by SDS-PAGE and immunoblotting. A smaller peak of [3H]vincristine binding and an amount of tubulin equal to that found in later fractions were found in the void volume during the same HPLC elution runs with cytosol from both variant and parental DC-3F cells. Evidence was also obtained for differences between parental and variant DC-3F cells in beta-tubulin isoforms following isoelectric focusing and immunoblotting. Parental-cell cytosol contains a single isoform of beta-tubulin. However, in variant cell cytosol the same isoform and, in addition, three more basic isoforms were found. These alterations in [3H]vincristine binding and in isoform compositions of beta-tubulin in variant versus parental DC-3F cells may have importance in regard to vincristine resistance in DC-3F cells.

Animals↗
PubMed1988

Comprehensive clinical and statistical analysis of hemophilia in Korea.

A Total of 498 cases of hemophilia which were reported by sixteen medical centers in Korea were reviewed and analyzed. Hemophilia A comprised 425 cases (85.3%) and the remaining 73 cases (14.7%) were hemophilia B. One case was female and all other cases were male. There were known hemophilia patients in the family in 43.0% of cases and the involved members were brothers, maternal cousins, maternal uncles, and maternal grandfathers in descending order of frequency. The major symptoms of the patients were hemorrhagic, such as easy bruising and hemarthrosis followed by prolonged bleeding after trauma and soft tissue hematoma. The incidence of hemarthrosis increased significantly with age. The pediatric age group below the age of 15 consisted of 67.1% of the cases. According to the age at diagnosis, half (54.2%) of the severe cases were diagnosed before the age of 1 year. APTT was prolonged over 40 seconds in all cases and 291 cases showed severe prolongation over 80 seconds. Of 498 cases 273 cases (54.8%) belonged to the severe form (factor VII or IX level, less then 1%), whereas 182 cases (36.5%) and 43 cases (8.7%) belonged to the moderate (factor VIII or IX, 2-5%) and mild form (factor VIII or IX, 6-25%), respectively, Chronic arthropathy was present in 236 cases (49.6%), and the incidence increased significantly with age. The management of chronic arthropathy most commonly employed was rehabilitation in 25.4% of cases, but in 50.8% no management was given at all. The involved joints in descending order of frequency were knees, elbows and ankles. The complications were intracranial hemorrhage, Gl bleeding and nerve palsy in 48, 24, and 13 cases, respectively.

Adolescent↗