Biomedical subjects

K C Yang

Publications and source records attributed to K C Yang.

At least 19 recordsLinked to original sources

PubMed2001

Identification of AF17 as a downstream gene of the beta-catenin/T-cell factor pathway and its involvement in colorectal carcinogenesis.

To elucidate the molecular mechanism of colorectal carcinogenesis, we have been attempting to isolate genes involved in the beta-catenin/T-cell factor pathway. In the experiments reported here, analysis by cDNA microarray indicated that AF17, a fusion partner of the MLL gene in acute leukemias with t(11;17)(q23;q21), was transactivated according to accumulation of beta-catenin. Expression of AF17 was significantly enhanced in 8 of the 12 colorectal cancer tissues examined. Introduction of a plasmid designed to express AF17 stimulated growth of NIH3T3 cells, and fluorescence-activated cell sorter analysis indicated that the AF17 regulation of cell-cycle progression was occurring mainly at the G(2)-M transition. Our results suggest that the AF17 gene product is likely to be involved in the beta-catenin-T-cell factor/lymphoid enhancer factor signaling pathway and to function as a growth-promoting, oncogenic protein. These findings should aid development of new strategies for diagnosis, treatment, and prevention of colon cancers and acute leukemias by clarifying the pathogenesis of these conditions.

3T3 Cells↗

PubMed2001

[Diagnosis of subtypes and lateralization for primary hyperaldosteronism].

OBJECTIVE: To evaluate the value of CT and posture stimulation test (PST) in the differential diagnosis and lateralization of primary hyperaldosteronism(PA). METHOD: Retrospective study was done based on the clinical data and pathological examinations of 22 patients with PA. RESULTS: The baseline plasma aldosterone concentration (PAC) of most aldosterone-producing adenomas (APAs) was over 250 pg.ml-1. In the diagnosis of APA, the sensitivity of CT was 75% and the specificity of CT was 100%; the sensitivity and specificity of PST were 87% and 100%, respectively. The examination results of CT and PST had no statistical significant correlativity (P > 0.05) and had bad consistency (P > 0.05), and the diagnostic efficiency of them had no significant difference (P > 0.05). CONCLUSIONS: The baseline PAC and the result of PST suggest as the best diagnostic index and methods of APA. Both CT and PST have high value in the differential diagnosis. Both CT and PST cannot be substituted for each other.

Adenoma↗

PubMed2000

Double-paddle peroneal tissue transfer for oromandibular reconstruction.

The double-paddle peroneal tissue transfer is a useful technique for reconstructing the extensive and complex defect that results after ablative surgery for oral cancer. It can facilitate the design and inset of the skin paddle and avoid the need for a second free flap. The two skin paddles can be based on either two cutaneous perforators of the peroneal vessels or two branches of a single cutaneous perforator. The authors report their experience with double-paddle peroneal tissue flaps (10 fasciocutaneous and five osteocutaneous) in 15 patients. The largest double paddle used was (16 x 9) (15 x 6) cm, and the smallest one was (7 x 5.5) (4.5 x 4) cm. All flaps were used for both intraoral and extraoral defect reconstruction. There was one single skin paddle necrosis caused by erroneous manipulation of the flap 1 week after the operation; however, the skin paddle had survived completely before the manipulation. All other flaps survived completely, with a good to excellent appearance, and no patient had a significant gait disturbance after the operation.

Aged↗

PubMed1999

Comparison of the frequency-doubled Q-switched Nd:YAG laser and 35% trichloroacetic acid for the treatment of face lentigines.

BACKGROUND: Face lentigines are one of the manifestations of photodamaged skin and often put people in socially embarrassing situations. Several lasers have been used to remove lentigines at vast expense. However, trichloroacetic acid (TCA) is an alternative for treating lentigines that costs much less. OBJECTIVE: To compare the efficacy of the frequency-doubled Q-Switched Nd:YAG laser (532 nm) and 35% TCA for the treatment of face lentigines. METHODS: Twenty patients (Fitzpatrick skin Types III-IV) with a total of 37 lentigines on faces were randomly collected; each lentigo was divided into medial and lateral halves. Frequency-doubled Q-switched Nd:YAG laser (532 nm) and 35% TCA were applied to the medial and lateral halves of each lentigo respectively. The efficacy after 1 treatment was compared after 6 months. RESULTS: The frequency-doubled Q-switched Nd:YAG laser (532 nm) had a better result than that of 35% TCA for the treatment of facial lentigines. CONCLUSION: In order to get a better result after one treatment, the authors suggest the frequency-doubled Q-switched Nd:YAG laser (532 nm) rather than 35% TCA for treating lentigines even though the cost of frequency-doubled Q-switched Nd:YAG laser (532 nm) is greater than that of 35% TCA for both physician and patient.

Adult↗

PubMed1999

Clinical experience with endoscopic stents for treatment of common bile duct stones.

Endoscopic removal of common bile duct (CBD) stones after endoscopic sphincterotomy (EST) is now a widely accepted procedure. Surgery is usually recommended when extraction of stones after EST fails. For patients with major medical problems or who are at high surgical risk, however, endoscopic stent placement may help to prevent stone impaction and cholangitis. In this report, we describe the long-term effects and complications of biliary stent use in elderly patients with CBD stones. From August 1995 to June 1998, 19 patients with CBD stones underwent stent placement by duodenoscopy. Three of these patients underwent this procedure for temporary treatment while awaiting surgery or EST. In the remaining 16 patients (6 men and 10 women, mean age 76 +/- 10 years), invasive management carried a high risk of complications. We used a 7F straight stent for the first patient, while the remaining 15 received 7F pigtail stents. During a mean follow-up period of 34 months, two patients were lost to follow-up and two patients had migration of the stents. Three patients had acute cholangitis with stents in situ. Of these, one underwent stent exchange 8 months later, while the CBD stones were cleared either by endoscopy or surgery in the other two patients. Five patients died of nonbiliary diseases during the follow-up period. Our results show that long-term biliary stent placement is an advisable alternative therapeutic modality for high-risk and debilitated patients with CBD stones.

Aged↗

PubMed1999

A multicenter study on eradication of Helicobacter pylori infection in patients with duodenal ulcer by lansoprazole-antibiotics combined therapy.

The aim of this prospective randomized multicenter study was to find out if there is one or several promising regimens containing lansoprazole with various combinations of antibiotics which have a high eradication rate of Helicobacter pylori, few side-effects, good patient compliance, and relative low cost if possible. Two hundred and ninety-seven patients with H. pylori positive duodenal ulcer were enrolled and randomly allocated into one of the five treatment groups: 1) group A: received lansoprazole 30 mg once daily for 2 weeks plus amoxicillin (AM) 500 mg and metronidazole (MZ) 500 mg twice daily for one week in the first week; 2) group B: the AM in group A was replaced by clarithromycin (CM) 250 mg; 3) group C: the MZ in group A was replaced by CM 250 mg; 4) group D: the AM and CM in group C was used for 2 wk; 5) group E: the CM in group D was doubled to 500 mg twice daily. All patients received endoscopies pre- and 4-6 weeks post termination of treatment. H. pylori was detected by culture, histology and rapid urease test (CLO test). 13C-urea breath test was performed if the patients refused the second endoscopy. The E-test was adopted to evaluate the MZ and CM resistance of H. pylori. Totally, 253 patients completed the study. The eradication rate of groups A, B, C, D and E were 75%, 80%, 78%, 92%, and 96%, respectively. The eradication rate of group E was significantly higher than that of groups A, B, or C. There were no significant differences of eradication rates between the groups D and E. Sixty-seven cases (28.8%) were MZ-resistant. The difference of eradication rates between MZ-S and MZ-R patients was significant in group A (85.3% vs. 42.9%) and in the combination of groups A and B (83.8% vs. 59.4%). Good compliance (defined as taking > 90% of medications) was seen in more than 90% of cases in each group. Triple therapy containing lansoprazole 30 mg once daily, AM 500 mg and CM 250 mg twice daily for two weeks is a promising regimen which reaches a high eradication rate, avoids MZ resistance, and has very good patient compliance at an acceptable cost.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1998

Substituted 3beta-phenylethynyl derivatives of 3alpha-hydroxy-5alpha-pregnan-20-one: remarkably potent neuroactive steroid modulators of gamma-aminobutyric acidA receptors.

Neuroactive steroids are positive allosteric modulators of gamma-aminobutyric acidA (GABAA) receptor complexes. Synthetic modification generally does not increase neuroactive steroid potency beyond that of the naturally occurring progesterone metabolite, 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha,5alpha-P). Recently, it has been shown that introduction of appropriately para-substituted phenylethynyl groups at the 3beta-position of 5beta steroids increases receptor potency. The present report presents the synthesis and pharmacological profile of an analogous series of 5alpha steroids. The most striking feature of this series is the further enhancement of in vitro and in vivo potency obtained. In particular, 3beta-(p-acetylphenylethynyl)-3alpha-hydroxy-5alpha-pr egnan-20-one (Co 152791) was 11-, 16- and 49-fold more potent than 3alpha, 5alpha-P in modulating the binding of [35S]TBPS, [3H]flunitrazepam and [3H]muscimol, respectively, in rat brain membranes (Co 152791 IC50 or EC50 = 2-7.5 nM). Similarly, Co 152791 was 3- to 20-fold more potent than 3alpha,5alpha-P as an inhibitor of [35S]TBPS binding in human recombinant receptor combinations containing alpha1, alpha2, alpha3 or alpha5 and beta2gamma2L subunits (Co 152791 IC50 1.4-5.7 nM). Co 152791 displayed low efficacy and 3alpha,5alpha-P had low potency at alpha4/6beta3gamma2L GABAA receptor complexes. Interestingly, Co 152791 demonstrated remarkable potency as a potentiator of GABA-evoked currents in Xenopus oocytes expressing alpha1beta2gamma2L receptors (EC50 0.87 nM), being 184-fold more potent than 3alpha,5alpha-P. High in vitro potency was also reflected in enhanced in vivo activity in that Co 152791 exhibited exceptional anticonvulsant potency, protecting mice from pentylenetetrazol-induced seizures at a approximately 5-fold lower dose than 3alpha,5alpha-P after i.p. administration (Co 152791 ED50 0.6 mg/kg). Moreover, Co 152791 was orally active (ED50 1.1 mg/kg) and exhibited a therapeutic index of 7 relative to rotorod impairment. The remarkable potency of Co 152791 as a positive allosteric modulator of GABAA receptors may be explained by its interaction with an auxiliary binding pocket in the neuroactive steroid binding site. In addition, modification at the 3beta-position probably hinders metabolism of the 3alpha-hydroxy group contributing to the exceptional anticonvulsant potency of this compound relative to other neuroactive steroids.

Animals↗

PubMed1997

3 alpha-Hydroxy-3 beta-(phenylethynyl)-5 beta-pregnan-20-ones: synthesis and pharmacological activity of neuroactive steroids with high affinity for GABAA receptors.

Neuroactive steroids that allosterically modulate GABAA receptors have potential uses as anticonvulsants, anxiolytics, and sedative-hypnotic agents. Recently, a series of pregnanes substituted with simple alkyl groups at the 3 beta-position were synthesized and found to be active in vitro. The present report describes the synthesis of a series of substituted 3 alpha-hydroxy-3 beta-(phenylethynyl)pregnan-20-ones and their in vitro structure-activity relationship determined by their potency for inhibition of [35S]TBPS binding in rat brain membranes. Appropriate substitution of the phenyl group results in ligands with particularly high affinity for the neuroactive steroid site on GABAA receptors (e.g., 4-acetyl 28, IC50 10 nM). The potency of selected steroids was confirmed electrophysiologically in oocytes expressing cloned human GABAA alpha 1 beta 2 gamma 2L receptors (e.g., compound 28, EC50 6.6 nM). Consistent with their in vitro activity, some of the 3 beta-(phenylethynyl)-substituted steroids displayed anticonvulsant activity in the pentylenetetrazol (PTZ) and maximal electroshock (MES) tests following ip administration in mice. Notably, the 3 beta-[(4-acetylphenyl)ethynyl]-19-nor derivative 36 demonstrated an attractive anticonvulsant profile (PTZ and MES ED50 values of 2.8 and 9.2 mg/kg, respectively). A new pharmacophore for the neuroactive steroid site of GABAA receptors is proposed based upon the high affinity of certain substituted 3 beta-(phenylethynyl) steroids.

Animals↗

PubMed1997

Distinct clinicopathologic characteristics of diffuse- and intestinal-type gastric cancer in Taiwan.

The clinicopathologic features of 221 patients with intestinal-type (IT) gastric cancer were compared retrospectively with those of 290 diffuse type (DT). Intestinal type was characterized by an older mean age (65.0 +/- 10.8 years vs. 56.2 +/- 13 years), a higher male-female ratio (2.56 vs. 1.06), predominance of blood group O (46.2% vs. 31.1%), and frequent habitual smoking (50.7% vs. 31.4%) and drinking (28.5% vs. 17.6%) than did DT. In contrast, DT had a higher frequency of positive history of parent or sibling with gastric cancer (9.3% vs. 4.1%) and blood group A (40.3% vs. 27.6%) than did IT. The distinguishing histologic features of DT included more Borrmann type IV (13.1% vs. 1.3%) but less Borrmann type I (1% vs. 7.2%), more frequent involvement of middle third (26.9% vs. 15.9%) and whole stomach (4.1% vs. 0%), and more peritoneal seeding (15.5% vs. 9%), lymph node metastasis (67.2% vs. 51%), and nerve permeation (34.1% vs. 24.4%), but less Helicobacter pylori infection (55.9% vs. 69.2%) when compared with those of IT. There was no difference in depth of tumor invasion, venous permeation, duodenal involvement, and postoperative survival between IT and DT. These distinct clinicopathologic features between IT and DT in Taiwan suggest the presence of a different pathogenic process for these two histologic subtypes of gastric cancer.

Adenocarcinoma↗

PubMed1997

Afferent loop syndrome complicated by a duodenal phytobezoar after Billroth-II subtotal gastrectomy.

We illustrate a rare late onset (10 yr) complication of gastric surgery with a combination of afferent loop syndrome and a large duodenal bezoar. The patient underwent a subtotal gastrectomy with Billroth II gastrojejunal anastomosis for benign peptic ulcer 10 yr ago. It was not until several days before this presentation that he suffered from epigastralgia and abdominal distension. Leukocytosis and abnormal blood biochemistry were found including amylase, lipase, alkaline phosphatase, total bilirubin, GOT, and GPT in which amylase was markedly elevated to 1188 U/L. Abdominal ultrasound scan and especially CT scan confirmed the diagnosis of a large bezoar in the dilated duodenal afferent loop. To our knowledge, the rare entity in our case is the first reported in the literature.

Abdominal Pain↗

PubMed1996

Lead poisoning caused by contaminated Cordyceps, a Chinese herbal medicine: two case reports.

Two cases of lead poisoning, caused by the Chinese herbal medicine Cordyceps, were reported to the Department of Health in a laboratory-based blood lead surveillance program. Such unusual cases of lead poisoning have not been previously reported. These two patients took Cordyceps herbal medicine for treatment of underlying diseases. Loss of appetite and anemic signs of lead poisoning were manifested in one patient with a blood lead level of 130 microg/dl, while the other patient was asymptomatic with a blood lead level of 46 microg/dl. The lead content in the Cordyceps powder was found to be as high as 20 000 ppm. After cessation of intake in the asymptomatic patient, and cessation of intake and treatment with chelating agents in the symptomatic patient, the blood lead levels returned to normal range. This report raises concerns about lead poisoning from unusual herbal medicine worldwide.

Aged↗

PubMed1995

Visual acuity changes throughout adulthood in normal, healthy eyes: seeing beyond 6/6.

There are many useful longitudinal and cross-sectional epidemiological studies of how visual acuity (VA) deteriorates with age. However, few studies have evaluated age-related VA changes in normal, healthy eyes. Data from three previous studies that included VA measurements taken with logMAR charts from subjects with normal, healthy eyes were collated and additional data from 42 subjects were added. This provided VA results from 223 subjects (age range 18 to 80 years). Mean logMAR VA improved from -0.13 (Snellen equivalent 6/4.5) in 18- to 24-year-olds to -0.16 (Snellen 6/4(-1)) in 25- to 29-year-olds and then gradually became worse with age to a mean value of -0.02 (Snellen 6/6+1) for subjects over 75 years of age. The inadequacy of 6/6 as a norm value of VA is illustrated. The data show VA levels far superior to the data from the standard references of Pitts (1982) and Weale. (1975, 82) We suggest that this is because we used logMAR charts (providing nontruncated data), the subject's optimal refractive correction (rather than habitual) and strict exclusion criteria ensuring that only subjects with normal, healthy eyes were recruited for the studies.

Adolescent↗

PubMed1993

Ultraviolet-induced lenticular fluorescence: intraocular straylight affecting visual function.

Ultraviolet radiation (UVR) excitation of fluorophores within the crystalline lens results in intraocular straylight. These fluorescent emissions are known to increase with age. The visual effect of this increase in fluorescent straylight has not previously been published. In this study, the visual deficit associated with UV-induced lenticular fluorescence was measured for 61 normal subjects between the ages of 21 and 80 yr of age using the Regan visual acuity charts at varying levels of contrast. UVR was shown to decrease low contrast acuity and this loss increased linearly with age.

Adult↗

PubMed1993

Anomalous junction of pancreaticobiliary duct with carcinoma of the gallbladder: report of two cases.

Anomalous junction of the pancreaticobiliary duct (AJPB) is a rare, congenital anatomic abnormality of the biliary system and is thought to be associated with a high risk of developing carcinoma of the gallbladder. We have had two cases of AJPB-associated gallbladder carcinoma in the past four years. Case 1: a 42-year-old female complaining of right upper quadrant pain was found in an abdominal sonogram to have irregular thickening of the gallbladder wall. Endoscopic retrograde cholangiopancreaticography revealed an abnormally elongated common channel; an abdominal CT scan and celiac angiogram showed a gallbladder tumor with invasion to the liver base. Case 2: a 36-year-old female presented with right upper quadrant pain and a palpable mass. A gallbladder tumor was found in an abdominal sonogram. Intraoperative cholangiography showed an abnormally elongated junction of the pancreaticobiliary duct. In these two cases, adenocarcinoma of the gallbladder was proven by pathology after surgical excision. Since AJPB and bladder carcinoma are both rare, the coexistence of these two diseases indicates that patients with AJPB have a high risk of developing gallbladder carcinoma. It is suggested that patients with AJPB should be closely followed. A prophylactic cholecystectomy may be indicated in some cases because of the high risk of developing gallbladder carcinoma.

Adenocarcinoma↗

PubMed1992

Geometrical optical analysis of photorefractive methods.

Photorefractive methods allow rapid measures of the refractive and accommodative state of infants and young children whose brief attention and co-operation limit the use of more traditional methods such as retinoscopy and autorefraction. Three methods have been defined: orthogonal, isotropic and eccentric. We provide a common geometrical optical analysis for these three methods where the photorefractive pattern is defined at the plane of focus of the camera. Since this plane is conjugate with the detector plane of the camera then the critical optical parameters can be defined without reference to the design of the camera by simply determining the relative magnification of the projected image of an object photographed at the camera's plane of focus. Specifically the pattern width CF (mm) over a photorefractor's working range can be defined for the isotropic and orthogonal methods as: [formula: see text] and for the eccentric method as: [formula: see text] where: K is a myopic refractive error of the eye (dioptres) (K Less than 0); P the distance of the flash source to the eye (dioptres); L the distance in front of the eye of the camera's plane of focus (dioptres) (L less than 0); GH the pupil diameter (mm); e the eccentricity of the flash source from the camera aperture (mm); M magnification of the image measured relative to the camera plane of focus.

Accommodation, Ocular↗

PubMed1992

Immunogenicity and protective efficacy of solubilized merozoite-enriched Theileria sergenti immunogens. II: Protection against natural exposure under field conditions.

A Theileria sergenti soluble merozoite preparation containing the 29, 34, 35 and 105 KD as the immunodominant polypeptides, was evaluated for efficacy, safety and protectivity in Holstein calves against virulent field tick challenge. The soluble antigens (100 mg/dose) were fortified with either complete or incomplete Freund's adjuvant. Twenty naive calves, aged one month, were subcutaneously inoculated with the preparation and a booster dose was administered 4 weeks later. Twenty additional calves served as controls. Five weeks after the booster dose, vaccinates and uninoculated controls were moved to a pasture, a heavily tick infested area in Cheju-do, Korea. The vaccinates showed negligible change in hematocrit and total RBC count whereas control animals showed significant (p < 0.05) hematological changes and associated anemia. Only 30% of vaccinates required chemotherapy after the experiment was terminated. All control animals required chemotherapy and 25% received blood transfusion. The highest percent parasitized erythrocytes in vaccinated cattle was 0.4% as compared with 3.6% among controls during the month of July. A significant difference (p < 0.05) was observed in the rate of body weight increase. Significant differences were also noted in serum albumin, aspartate aminotransferase, total protein and bilirubin. Significantly more vaccinated cattle maintained normal ranges of hematological and biochemical values as compared with the control group. It is suggested that soluble merozoite T. sergenti antigens may be potential vaccine candidates for developing a genetic vaccine in Korea.

Animals↗

PubMed1992

[Clinical analysis of adenocarcinoma of the stomach in patients with duodenal ulcer].

In 332 patients of adenocarcinoma of the stomach and 7095 patients with duodenal ulcer collected in 5-year period, 21 cases were found to have both disease entities. With regard to clinical manifestations, gross morphology, microscopic differentiation and management of adenocarcinoma of the stomach, the patients with duodenal ulcer showed no significant difference from those without duodenal ulcer. The activities of the duodenal ulcers could be in acute active stage or present as chronic scar only. The ulcer history varied from several years to more than 15 years. We concluded that the frequency of adenocarcinoma of the stomach developed in patients with duodenal ulcer is not so rare, presentation of epigastric discomfort or signs of UGI bleeding in patients with duodenal ulcer history not always indicated recurrence of ulcer disease.

Adenocarcinoma↗

PubMed1990

[Malignant melanoma metastatic to the stomach: upper G-I endoscopic finding--report of a case].

a 54-year-old male was presented with huge, black, ulcerative and painless tumor of the sole of left foot. Malignant melanoma was proved by biopsy, but patient refused any treatment. He visited our hospital again when bloody vomitus was noted two months later. Chest P-A revealed multiple lung metastases, and marked liver metastasis was also found by abdominal echo. Upper gastrointestinal (UGI) panendoscopy revealed multiple melanotic nodules with ulcerations at the tip, scattering diffusely on the fundus and upper body of the stomach. Metastatic malignant melanoma was proved by endoscopic biopsy. Metastatic tumor of the stomach was rare, and the endoscopic finding of the malignant melanoma with gastric metastasis was more rarer in the literature in Taiwan. So we would like to present the very rare finding of the endoscopy.

Gastroscopy↗