Biomedical subjects

C C Yang

Publications and source records attributed to C C Yang.

At least 73 records · Page 4Linked to original sources

PubMed2000

Migration of endoclip into duodenum. A rare complication after laparoscopic cholecystectomy.

The long-term effect of spilled clips within the abdominal cavity after laparoscopic cholecystectomy is unknown. However, most surgeons agree that the migration of clips has limited clinical consequences. A few cases have been reported of clips that have migrated into the common bile duct, causing stone formation and/or obstructions. We present a case of gallstone pancreatitis treated with laparoscopic cholecystectomy that was complicated by bile leakage from the cystic duct stump 1 day after the procedure. Although the leaking stump sealed itself spontaneously after the placement of a biliary stent, a clip had migrated directly to the superior wall of the first portion of the duodenum. Herein the details of the patient's history are presented. We also discuss the possible mechanisms of clip migration and describe some preventive measures.

Bile↗

PubMed2000

Suppression of proline-directed protein kinase F(A) expression potentiates erythroid differentiation of human myeloid leukemia cells.

BACKGROUND: Initial clinic studies revealed that the overexpression of proline-directed protein kinase F(A) (PDPK F(A)) is associated conversely with various stages of tumor tissue differentiation. However, the role of overexpressed PDPK F(A) in tumor cell differentiation remains unknown and needs to be established. In this report, the authors explore the potential role of PDPK F(A) in cellular differentiation by investigating the effects of partial inhibition of this kinase on erythroid differentiation of chronic myeloid leukemia cells (K562). METHODS: PDPK F(A) antisense expression vector and its specific antibody were developed successfully. Two stable, transfected antisense clones of human myeloid leukemia cells were subcloned that expressed approximately 80% and approximately 50% of the total PDPK F(A) existing in control-transfected clones, as determined by both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, the PDPK F(A) antisense clones expressed no significant suppression of any other related PDPK members' expression, demonstrating the specificity of these two antisense clones. RESULTS: The antisense clones proportionally induced spontaneous erythroid differentiation up to approximately 30% of the total K562 cells. Moreover, antisense suppression of PDPK F(A) expression appeared to potentiate sodium butyrate/hemin-induced erythroid differentiation of K562 cells to a more complete stage compared with the control. CONCLUSIONS: The results demonstrate that specific antisense suppression of overexpressed PDPK F(A) in human myeloid leukemia cells is sufficient to potentiate both spontaneous and drug-induced erythroid differentiation, indicating that PDPK F(A) is an important negative regulator in controlling the erythroid differentiation of human myeloid leukemia cells.

Antisense Elements (Genetics)↗

PubMed2000

Opposition of rapid baroreceptor resetting by prostanoids in rabbits.

Arterial baroreceptors reset rapidly within minutes during acute hypertension; baroreceptor pressure threshold (Pth) is increased and the pressure-baroreceptor activity relation is shifted to the right. The purpose of the present study was to determine if prostacyclin (PGI2) or other prostanoids, released during acute hypertension modulate the magnitude of baroreceptor resetting. Baroreceptor activity was recorded from the vascularly-isolated carotid sinus during distension of the sinus with slow pressure ramp in rabbits anesthetized with chloralose. Pressure-activity curves were generated after holding carotid sinus pressure for 10-15 min from 30 to 100 mmHg. In control, the elevation of holding pressure increased Pth from 44+/- to 65+/-5 mmHg (p < 0.05, n = 12). In the presence of PGI2 (20 microM), Pth averaged 43+/-4 and 45+/-3 mmHg (n = 12) after holding pressure at 30 and 100 mmHg, respectively. In the control group before exposing the carotid sinus to indomethacin, an elevation of holding pressure increased Pth from 49+/-2 to 71+/-3 mmHg (p < 0.05, n = 12). After inhibition of the endogenous formation of prostanoids with indomethacin (20 microM), Pth increased by a significantly greater extent from 61+/-2 to 90+/-3 mmHg (p < 0.05, n = 12) with the increase in holding pressure. The slope of the pressure-activity curve (baroreceptor gain) was not influenced by the change in holding pressure. It was increased significantly by PGI2, while decreased by indomethacin. Neither the change in holding pressure nor PGI2 affected the circumferential wall strain of carotid sinus over a wide range of pressure alteration. The results suggest that PGI2 or other prostanoids released during acute hypertension sensitizes baroreceptors and provides a negative feedback mechanism that opposes and limits the magnitude of rapid baroreceptor resetting.

Animals↗

PubMed2000

Resectional treatment for thyroid cancer with tracheal invasion: a long-term follow-up study.

HYPOTHESIS: Transmural invasion of the trachea by well-differentiated thyroid carcinomas is a locally advanced disease condition. It frequently causes deaths owing to airway obstruction. We hypothesized that resection of the invaded trachea followed by primary anastomosis provides the opportunity for cure. DESIGN: A retrospective review study of medical records. SETTING: The surgical department of a tertiary referral center. PATIENTS: Eight patients with well-differentiated thyroid carcinomas, complicated with tracheal invasion resulting in bleeding and airway obstruction, operated on by tracheal resection and immediate anastomosis, were included. INTERVENTIONS: All patients received total thyroidectomy and neck lymph node dissection as well as segmental tracheal resection followed by primary reconstruction. Postoperative radioactive sodium iodine I 131 treatment and suppression therapy with thyroxine were applied to all of them. MAIN OUTCOME MEASURE: Postoperative follow-up of serum levels of human thyroglobulin and abnormal radioactive iodine 131I from whole body scan. RESULTS: Seven patients are alive. Of these patients, 5 had no evidence of disease: (3 had no evidence of cancer for more than 10 years' follow-up), 2 had regional lymph node metastasis, and 1 had lung metastases. The remaining patient had anastomotic site recurrence with airway obstruction and needed tracheostomy to relieve stridor. She was lost to follow-up 39 months after undergoing the initial operation. CONCLUSIONS: Patients with mucosal invasion of the trachea by well-differentiated thyroid carcinomas should be treated by surgical resection followed by primary reconstruction when technically feasible. This facilitates postoperative care, and it is possible to achieve long-term survival with improvement of the quality of life and possible cures.

Adult↗

PubMed2000

Impact of pulse pressure on the respiratory-related arterial pressure variability and its autonomic control in the rat.

The autonomic control of respiratory-related arterial pressure variability (RAPV) remains uncharacterised. We set out to test the hypothesis that the autonomic nervous system may participate in RAPV via its effect on pulse pressure (PP). Experiments were performed on adult male Sprague-Dawley rats anaesthetised with ketamine and paralysed with pancuronium under positive-pressure ventilation. Respiratory variability in each parameter was quantified by auto-spectral analysis and the relationship between variabilities in two signals assessed by cross-spectral analysis. PP and systolic pressure (SP) exhibited similar powers of respiratory variability that were far more pronounced than for diastolic pressure (DP) or mean pressure (MP). The variability in PP preceded that in SP, MP or DP. The largest phase lag occurred between PP and DP and was equivalent to the time delay of one pulse interval. Coherence between respiratory variabilities in PP and MP was nearly perfect. Propranolol dose dependently suppressed respiratory variability in each pressure parameter and eventually disrupted the PP-MP relationship in respiratory variability. However, the influence of lung volume on MP persisted with a near-zero phase lag. Combined administration of phentolamine and atropine facilitated respiratory variability in PP and SP and failed to block the effect of propranolol. However, the combined administration moved the dose/response curve of propranolol and respiratory variability in each pressure parameter to the right. We conclude that, in addition to non-autonomic mechanisms, RAPV may be facilitated by cardiac sympathetic function via the effect on PP variability. The autonomic mechanism can still be evoked during combined alpha-adrenoceptor and muscarinic blockade, possibly via baroreflex mechanisms.

Adrenergic alpha-Agonists↗

PubMed2000

Antegrade continence enema for the treatment of neurogenic constipation and fecal incontinence after spinal cord injury.

OBJECTIVE: To describe the effects of an antegrade continence enema stoma formed in a paraplegic man with intractable constipation and fecal incontinence. DESIGN: Case report. SETTING: Spinal cord injury unit, Veterans Affairs hospital. PARTICIPANTS: Spinal cord injury (SCI) patient with T12 paraplegia. INTERVENTION: Surgical formation of antegrade continence enema stoma. MAIN OUTCOME MEASURES: Time of bowel program care, ease of fecal elimination, safety of procedure. RESULTS: Bowel care time was decreased from 2 hours to 50 minutes daily; 6 bowel medications were discontinued; fecal incontinence was eliminated; and no surgical or medical side effects noted after the procedure. CONCLUSION: The antegrade continence enema procedure is a safe and effective means of treating intractable constipation and fecal incontinence in the adult SCI patient. This option should be considered for those persons in whom medical management of bowel care has been unsuccessful.

Cecostomy↗

PubMed2000

Rapid separation of lysozyme from chicken egg white by reductants and thermal treatment.

Reductants (0.1-2.0% ascorbic acid, cysteine, or cystine and 0.04-1. 0% beta-mercaptoethanol) were added to 5-fold diluted, salted duck egg whites (commercially and laboratory prepared) and fresh egg whites (chicken and duck), and subsequently the mixtures were heated at 70 degrees C for 1-10 min. The maximal recovery and purification fold of lysozyme obtained from fresh chicken egg whites added with 1. 0% ascorbic acid were 78% and 2.4, respectively. Storage tests showed that the obtained lyophilized lysozyme powder after dialysis was stable when refrigerated at 4 degrees C for 3 months.

Animals↗

PubMed2000

Repair of CFTR mRNA by spliceosome-mediated RNA trans-splicing.

Most messenger RNA precursors (pre-mRNA) undergo cis-splicing in which introns are excised and the adjoining exons from a single pre-mRNA are ligated together to form mature messenger RNA. This reaction is driven by a complex known as the spliceosome. Spliceosomes can also combine sequences from two independently transcribed pre-mRNAs in a process known as trans-splicing. Spliceosome-mediated RNA trans-splicing (SMaRT) is an emerging technology in which RNA pre-therapeutic molecules (PTMs) are designed to recode a specific pre-mRNA by suppressing cis-splicing while enhancing trans-splicing between the PTM and its pre-mRNA target. This study examined the feasibility of SMaRT as a potential therapy for genetic diseases to correct mutations using cystic fibrosis (CF) as an example. We used several versions of a cystic fibrosis transmembrane conductance regulator (CFTR) mini-gene expressing mutant (deltaF508) pre-mRNA targets and tested this against a number of PTMs capable of binding to the CFTR target intron 9 and trans-splicing in the normal coding sequences for exons 10-24 (containing F508). When 293T cells were cotransfected with both constructs, they produced a trans-spliced mRNA in which normal exon 10-24 replaced mutant exon 10. To test whether SMaRT produced mature CFTR protein, proteins were immunoprecipitated from lysates of cotransfected cells and detected by Western blotting and PKA-phosphorylation. Tryptic phosphopeptide mapping confirmed the identity of CFTR. This proof-of-concept study demonstrates that exon replacement by SMaRT can repair an abnormal pre-mRNA associated with a genetic disease.

Blotting, Western↗

PubMed2000

Reflex innervation of the bulbocavernosus muscle.

OBJECTIVE: To determine the somatic reflex innervation of the bulbocavernosus muscle (BCM) and to illustrate the role of the perineal nerve in BCM contraction, using electrophysiological techniques. Subjects and methods Ten healthy, potent men underwent genital electrophysiological testing. Stimuli were applied to the dorsal nerve of the penis at the base of the penis, glans and anterior urethra, and the perineal nerve branch to the BCM. The electromyographic (EMG) responses of the BCM were recorded and onset latencies measured at baseline, both after anaesthetising the perineal nerve and after recovery from the anaesthetic. RESULTS: A reflex BCM contraction was elicited from all stimulation sites. Anaesthetizing the perineal nerve resulted in alterations of the EMG response. After the anaesthetic effect wore off, the responses returned to baseline values. CONCLUSIONS: Three distinct somatic bulbocavernosus reflexes were detected which are components of normal ejaculation. BCM contraction can be elicited after stimulating the dorsal penile nerve at the glans and the anterior urethra; these are the flexor responses of the bulbocavernosus reflex. BCM contraction can also be induced on stimulating the perineal nerve, which is the pathway through which the stretch and the tendon organ reflexes are carried to mediate muscle tone. The motor innervation of the BCM for all reflexes is carried through a branch of the perineal nerve. The findings may be relevant to the evaluation of ejaculatory disorders.

Adult↗

PubMed2000

Suppression of proline-directed protein kinase F(A) expression inhibits the growth of human chronic myeloid leukaemia cells.

Initial studies revealed that proline-directed protein kinase F(A) (PDPK F(A)) was overexpressed in various cancerous tissues relative to normal controls. However, the functional role of overexpressed PDPK F(A) in cancer remains to be established. In this report, we explore the potential role of PDPK F(A) in leukaemia cell growth by investigating the effects of partial inhibition of this kinase on the malignant phenotype of human chronic myeloid leukaemia cells (K562). Cloning of PDPK F(A) cDNA and its recombinant antisense expression vector and PDPK F(A)-specific antibody were successfully developed. Two stable antisense clones of K562 cells were subcloned which expressed 70% and 45% of PDPK F(A) respectively, compared with control-transfected clone in both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, these two antisense clones expressed no significant suppression of any other related PDPK family members, indicating the specificity of these two antisense clones. Moreover, these antisense clones proportionally and potentially exhibited cell growth retardation, poor clonogenic growth in soft agar and loss of serum independence. The results demonstrate that specific antisense suppression of PDPK F(A) is sufficient to interfere with the growth of K562 cells, indicating that PDPK F(A) is essential for human chronic myeloid leukaemia cell growth.

Amino Acid Sequence↗

PubMed2000

Inadequate stocking of antidotes in Taiwan: is it a serious problem?

OBJECTIVE: Insufficient hospital stock of a variety of poisoning antidotes is a worldwide problem. In an attempt to establish an antidote storage and distribution system for the response of the various poisoning accidents, we conducted a nationwide survey to characterize the current availability of selected antidotes and their anticipated need in Taiwan. MATERIALS AND METHODS: A questionnaire was mailed to 834 hospitals to gather information on the availability, anticipated need, and preferred purchase policy of 20 selected antidotes. A survey on the availability of cyanide antidote in 523 cyanide-handling facilities and their neighboring hospitals was also conducted. RESULTS: Hospitals of different size and service levels had a statistically significant difference in response rates. Except for pyridoxine, the availability and anticipated need for antidotes also varied significantly among different hospital groups. We found that physostigmine, cyanide antidote kit, BAL, EDTA, methylene blue, Vipera Russell formosensis antivenin, and botulism antitoxin were not available in most (>90%) hospitals. Interestingly, these antidotes are also among the most needed antidotes. Most hospitals preferred a government-ordered purchase of antidotes. In the survey of cyanide-processing facilities, a response rate of 24.1% was obtained and only 9.3% of these 107 facilities that both replied to the questionnaire and continued handling cyanide products had stocked cyanide antidote. It is noteworthy that cyanide antidote was also frequently lacking in the neighboring hospitals. CONCLUSIONS: The appropriate storage of antidotes in hospitals or workplaces in rural areas is instrumental in the timely treatment of certain poisonings, while nationwide unavailability is the critical problem. Raising awareness of the importance of antidotes by education, regular review of antidote storage, distribution plans, and appropriate legislation might provide solutions.

Antidotes↗

PubMed2000

Altered frequency characteristic of central vasomotor control in SHR.

Previous work from our laboratory has demonstrated that the very low-frequency (VLF: 0-0.25 Hz) and low-frequency (LF: 0.25-0.8 Hz) power of arterial pressure variability (APV) are related to vasomotor reactivity in response to control signals from the rostral ventrolateral medulla (RVLM) via the sympathetic system in the rat. The present study evaluated the differences in the dynamic property of central vasomotor control between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Experiments were carried out in 10- to 12-wk-old rats that were anesthetized with continuous infusion of pentobarbital sodium, paralyzed with pancuronium, and maintained on mechanical ventilation. We found that SHR exhibited significantly higher arterial pressure (AP), heart rate (HR), and VLF, LF, and high-frequency (0.8-2.4 Hz) power of APV than WKY under resting state. Broad-band electrical stimulation of the RVLM elicited parallel APV in the VLF and LF ranges in both rat strains. The evoked APV and transfer magnitude of the APV to stimulus spike rate variability (RVLM-AP magnitude) were significantly higher in SHR, especially in the LF range. The response frequency of central vasomotor control, represented by the high-cut frequency of RVLM-AP magnitude, was also extended in SHR. The disparity in RVLM-AP transfer magnitude between SHR and WKY became virtually absent after combined alpha- and beta-adrenoceptor blockade by phentolamine and propranolol. These results suggest that the dynamic control of RVLM on AP reactivity is enhanced in SHR, in which the adrenergic system may play a major role.

Action Potentials↗

PubMed2000

Preeclamptic pregnancy is associated with increased sympathetic and decreased parasympathetic control of HR.

Previous work from our laboratory using heart rate variability (HRV) has demonstrated that women before menopause have a more dominant parasympathetic and less effective sympathetic regulations of heart rate compared with men. Because it is still not clear whether normal or preeclamptic pregnancy coincides with alternations in the autonomic functions, we evaluated the changes of HRV in 17 nonpregnant, 17 normotensive pregnant, and 11 preeclamptic women who were clinically diagnosed without history of diabetic neuropathy, cardiac arrhythmia, and other cardiovascular diseases. Frequency-domain analysis of short-term, stationary R-R intervals was performed to evaluate the total variance, low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), ratio of LF to HF (LF/HF), and LF in normalized units (LF%). Natural logarithm transformation was applied to variance, LF, HF, and LF/HF for the adjustment of the skewness of distribution. We found that the normal pregnant group had a lower R-R value and HF but had a higher LF/HF and LF% compared with the nonpregnant group. The preeclamptic group had lower HF but higher LF/HF compared with either the normal pregnant or nonpregnant group. Our results suggest that normal pregnancy is associated with a facilitation of sympathetic regulation and an attenuation of parasympathetic influence of heart rate, and such alterations are enhanced in preeclamptic pregnancy.

Adult↗

PubMed2000

Intracranial fibrosarcoma arising 5 years after chemotherapy alone for glioblastoma multiforme in a child.

We present a child diagnosed with glioblastoma multiforme during infancy and successfully treated with the 'eight-in-one' chemotherapy regimen, who developed an intracranial fibrosarcoma 5 years later. After resection of the fibrosarcoma, she received cranial radiation therapy and high dose chemotherapy with bone marrow transplant. She remains alive and recurrence-free 7 years following the diagnosis of her second intracranial malignancy.

Bone Marrow Transplantation↗

PubMed2000

Antisense suppression of proline-directed protein kinase FA enhances chemosensitivity in human prostate cancer cells.

Initial clinic studies revealed that proline-directed protein kinase FA (PDPK FA) is overexpressed manyfold in various human cancerous tissues relative to the normal control. However, the role of overexpressed PDPK FA in cancers remains unknown and needs to be established. To determine whether PDPK FA is associated with drug sensitivity, we investigated the effects of partial inhibition of this kinase on the human prostate carcinoma cell line (PC-3). PDPK FA antisense expression vector and its specific antibody were successfully developed. Two stable transfected antisense clones (PA7 and PA3) of human prostate carcinoma cell were subcloned, and they expressed approximately 75% and approximately 35% of the total PDPK FA existing in the control-transfected clone as determined by both immunoprecipitate activity assay and immunoblot analysis. In sharp contrast, the PDPK FA antisense clones expressed no significant suppression of any other related proline-directed protein kinase member expression, demonstrating the specificity of these two antisense clones. When compared with parental or control-transfected cells, the low-PDPK FA-expressing antisense clones displayed an enhanced sensitivity to carboplatin, 5-fluorouracil, paclitaxel, and hydroxyurea. Estimation of the IC50 index further revealed that the antisense clones displayed up to > 100-fold drug sensitivity, and there was a correlation between suppressed levels of PDPK FA and drug sensitivity. Taken together, the results demonstrate that specific antisense suppression of overexpressed PDPK FA in human prostate cancer cells is sufficient to enhance various drug sensitivity, indicating that PDPK FA is an important regulator in controlling multiple drug resistance of human prostate cancer cells.

Antineoplastic Agents↗

PubMed2000

Laparosopic removal of large gastric phytobezoars.

Large gastric bezoars are difficult to remove endoscopically. A 78-year-old man presenting with abdominal pain and loss of appetite for 4 months was admitted and evaluated. Gastroscopy disclosed two large phytobezoars within the stomach. Laparoscopic removal was undertaken. The bezoars were removed via a gastrotomy using the three-trocar technique. They were successfully retrieved from the abdominal cavity using an improvised "endobag" made from a simple surgical glove. Such an endobag presents several advantages; they are easy to make, sterile, economical, readily available, disposable, there is ample space to manipulate the specimen within, and there is minimal risk of contamination throughout the procedure. The authors recommend this approach for the treatment of patients with large gastric bezoars in whom laparotomy is indicated.

Abdominal Pain↗

PubMed2000

Liberal use of a bag made from a surgical glove during laparoscopic surgery for specimens retrieval.

Laparoscopic surgery has been gaining wide acceptance in recent years. Tissue removal from the abdominal cavity becomes a paramount issue, especially when the specimen is infected, contains several fragments, or potentially contains a malignancy. Several sophisticated instruments and devices have been designed for this purpose. However, most of these are expensive, difficult to handle, and come in a fixed size. Condoms, glove fingers, and zipper-type plastic bags have been tried also, but with limited success. The authors report use of a simple bag made from a surgical glove to collect specimens; a long purse-string suture surrounds the opening or the base of the glove finger to secure material during retrieval. This method has been found to be simple and convenient, and necessary construction material is readily available. The bag not only protects the specimen from contact with the wound but also cuts short the operating time. The technique and advantages are described.

Gloves, Surgical↗

PubMed2000

Current seroprevalence of hepatitis A virus infection among kindergarten children and teachers in Taiwan.

Taiwan was a hyperendemic area for hepatitis A virus (HAV) infection before the late 1980s. The seroprevalence of HAV infection was higher than 90% with most HAV infection occurring during childhood. This study was to estimate the seroprevalence of HAV infection among preschool children in central Taiwan. A community-based survey was carried out in 54 kindergartens in 10 urban areas, 10 rural areas and 2 aboriginal areas randomly selected through stratified sampling. Serum samples of 2,549 healthy preschool children and 104 teachers in study kindergartens were screened for the HAV antibodies (anti-HAV) by means of a commercially available microparticle enzyme immunoassay (AxSYM HAVAB). Among aboriginal kindergarten children, more than 96% of them were anti-HAV seropositive due to a mass HAV vaccination program. In urban and rural areas, kindergarten children had a very low prevalence of anti-HAV (0.4%) in contrast to a high seroprevalence in their teachers (78%). There was no gender difference in seroprevalence of anti-HAV, while the anti-HAV seroprevalence was significantly higher in urban areas than in rural areas. Crowdedness of living in urban areas might facilitate the person-to-person transmission of infectious agents.

Adult↗