Biomedical subjects

C C Yang

Publications and source records attributed to C C Yang.

At least 109 records · Page 6Linked to original sources

PubMed1999

Bilateral gluteal dystrophic calcification--a case report.

Abnormal deposits of calcium in the injured and necrotic tissue (dystrophic calcification) are not considered to be rare conditions in human pathologic records. We report a severe case of bilateral gluteal calcification that has not often been found in the literature. It was caused by multiple intramuscular and/or subcutaneous injections. The multiple lumps along with the chronic unhealed fistula over the gluteal regions were successfully treated by carbon dioxide laser without recurrence. The pathogenesis of variable possibilities were reviewed and discussed.

Calcinosis↗

PubMed1999

Iatrogenic abdominal scar endometriosis: a case report.

We report the case of a patient with abdominal scar endometriosis following a cesarean section. The rarity of this localization and its appearance on computerized tomography is shown. We emphasize the combination of history and image study of this pathology in the differential diagnosis of other diseases.

Abdominal Muscles↗

PubMed1999

Characteristics and risk factors of acetaminophen-induced hepatitis in Taiwan.

BACKGROUND: Overdose of acetaminophen may cause hepatic injury and fatal fulminant hepatic failure. Acetaminophen is the most common form of drug-induced hepatic injury in Western countries. However, there is no formal report of this important issue in Taiwan. To assess the clinical characteristics and risk factors of acetaminophen-induced hepatitis in Taiwan, we conducted this study. METHODS: A total of 71 patients who were intoxicated or overdosed with acetaminophen at Veterans General Hospital-Taipei between February, 1991 and June, 1997 were enrolled in this study. Acetaminophen-induced hepatitis was defined according to the Paris international consensus criteria. RESULTS: Suicide attempt was the major cause (67/71) of acetaminophen overdose. Sixty-two of the patients were female. The mean patient age was 24.5 +/- 9.7 years (+/- standard deviation, SD). Nineteen of 71 patients had acetaminophen-induced hepatitis. The peak serum alanine aminotransferase, aspartate aminotransferase and total bilirubin concentrations were 4,181.0 +/- 931.4 IU/l (mean +/- SD), 4,148.0 +/- 1,147.5 IU/l and 2.6 +/- 0.4 mg/dl, respectively. The hepatitis group had higher ingested acetaminophen doses and serum peak acetaminophen levels than did those of the nonhepatitis group (24.9 g vs 12.9 g, p = 0.004; 132.0 mg/l vs 61.7 mg/l, p = 0.013). A higher percentage of alcohol consumption was also noted in the hepatitis group than in the nonhepatitis group (32% vs 12%, p = 0.05). After logistic regression for multivariate analysis, alcohol consumption was the most important risk factor for acetaminophen-induced hepatitis (odds ratio = 8.14, p = 0.018), followed by ingested acetaminophen dose (odds ratio = 1.21, p = 0.001). Most patients received acetylcysteine treatment in time. Two of the 19 patients with hepatitis died. CONCLUSIONS: The majority of acetaminophen-induced hepatitis in Taiwan occurs in young females who attempt suicide. Alcohol consumption and the dose of acetaminophen ingested were the significant risk factors for acetaminophen-induced hepatitis. Alcohol should not be concomitantly used with acetaminophen. Early diagnosis and administration of the antidote are crucial to decrease mortality.

Acetaminophen↗

PubMed1999

Management of pancreatic pseudocysts by endoscopic cystogastrostomy.

Open surgical drainage is currently the treatment of choice for pancreatic pseudocysts, but endoscopic transmural drainage is another minimally invasive surgical alternative. In this report, we describe two patients with symptomatic pancreatic pseudocysts treated with endoscopic cystogastrostomy. The first patient, a 15-year-old boy, had an episode of traumatic pancreatitis after abdominal injury from a car accident, and complained of postprandial vomiting and abdominal distention 4 weeks later. A large pancreatic pseudocyst, about 10 cm x 6 cm, was noted. The second patient, a 44-year-old man, had a 1-year history of recurrent alcoholic pancreatitis prior to this admission. He suffered from abdominal distention for several weeks. Sonography revealed a large pancreatic pseudocyst, about 18 cm x 9 cm in size. Both patients underwent successful endoscopic cyst-drainage without recurrence. These cases illustrate that endoscopic transmural drainage provides a minimally invasive and effective approach to the management of pancreatic pseudocysts.

Adolescent↗

PubMed1999

Cobrotoxin: structure and function.

Cobrotoxin is the main neurotoxic protein isolated from the venom of Taiwan cobra Naja naja atra. It is a small, basic protein consisting of a single polypeptide chain of 62 amino acids, cross-linked by four disulfide bonds. The disulfide bonds and Tyr-25 which is buried in the molecule form a central core to maintain and stabilize the active conformation of the toxin. Selective and stepwise chemical modifications of cobrotoxin indicate that at least two cationic groups, an epsilon-amino group of Lys-47 and a guanidino group of Arg-33, both of which are common to all known postsynaptic neurotoxins, held at a certain critical distance in the molecule, are functionally important for its neuromuscular blocking activity. The cDNA encoding cobrotoxin was constructed from the cellular RNA isolated from the venom glands of Naja naja atra by reverse transcription polymerase chain reaction. Sequencing several clones containing about 0.5 Kb DNA inserts contained a complete and full-length reading frame of 249 base pairs covering a precursor of cobrotoxin gene with a deduced mature protein sequence of 62 amino acids which are identical to the amino acid sequence of cobrotoxin and a 21 amino acid segment of signal peptide. Expression of cobrotoxin in E. coli vector generated a polypeptide which can cross-react with the antisera against the native cobrotoxin.

Amino Acid Sequence↗

PubMed1999

Sequence requirements for incorporation of human immunodeficiency virus gag-beta-galactosidase fusion proteins into virus-like particles.

The incorporation of human immunodeficiency virus type 1 (HIV-1) Gag-beta-galactosidase (Gag-beta-gal; GBG) fusion proteins into HIV virus-like particles in the presence of HIV Gag proteins was studied. HIV Gag-beta-gal fusion constructs were cotransfected individually into COS7 cells with or without an HIV Gag protein expression plasmid. Release of HIV GBG fusion proteins from the cells were measured by assay of the medium versus intracellular beta-gal activities. Analysis indicates that fusion proteins (constructs HIVGBG, GBG 1919 and 1877) retaining the C-terminal portion of the CA and the adjacent NC domains were efficiently assembled into virus-like particles. Fusion proteins with deleted sequences covering the N-terminal portions of the gag sequences (GBG 831, 1147, 1419, 1447, 1511, 1552, 1600, 1630, 1684, 1715, and 1752) were impaired in entry into virus-like particles. The presence of CA major homology region (MHR) in the fusion proteins had no significant effects on inducing fusion protein incorporation when the C-terminal CA sequences in the fusion proteins were truncated (GBG 1841 and 1801). Subcellular fractionation studies indicated that most fusion proteins including the nonmyristylated one were enriched in the crude membrane fraction. Exceptions to this rule were fusion proteins with intact MHR but truncated C-terminal CA sequences, which possessed low levels of membrane association. However, assembly of fusion proteins into HIV Gag particles did not correlate with their subcellular fractionation or immunofluorescence localization patterns. Overall, the studies suggest that the very C-terminal CA and adjacent NC sequences are the primary determinants for incorporation of HIV Gag-beta-gal fusion proteins into virus particles.

Animals↗

PubMed1999

Hemodialysis as adjunctive therapy for severe acetaminophen poisoning: a case report.

Acetaminophen overdose is a common intoxication in daily practice the standard treatment is N-acetylcysteine (NAC) antidotal therapy for possible poisoning. However, dialysis procedures can remove the drug from the body effectively. We describe a case of acetaminophen overdose that was treated with both hemodialysis (HD) and NAC due to severe intoxication and slow drug clearance. A 37-year-old woman attempted suicide by ingestion of 100 tablets (500 mg each) of acetaminophen, and presented with vomiting, hematemesis and abdominal pain. The patient had elevated liver enzymes, coagulation defects, thrombocytopenia a high serum acetaminophen level (201 mg/l at 12 hours post-ingestion) with a prolonged half-life. Oral NAC was given; however, it was ineffective due to severe vomiting and hematemesis. HD as adjunctive therapy was initiated at 19 hours post-ingestion. HD reduced the serum acetaminophen level from 102.77 to 35.77 mg/l. Severe hepatic injury, bacteremia and pancytopenia were noted in the following days. The patient later recovered after treatment with NAC, HD and intensive supportive care. HD removed 66% of the total acetaminophen body burden during a single four-hour session, increased the clearance by 2.75-fold and shortened the half-life from 7.2 hours to 2.6 hours during HD. Through NAC therapy is the standard regimen for acetaminophen poisoning, in the severely poisoned patient who cannot tolerate NAC therapy, HD may be used as adjunctive therapy to enhance the elimination of acetaminophen.

Acetaminophen↗

PubMed1999

Laparoscopic resection of an omental cyst with pedicle torsion.

Omental cysts are the least-common variety of all types of intra-abdominal cystic lesions. In the past, transabdominal laparotomy with excision of the cyst was the treatment of choice. With the advent of laparoscopic surgery, it has become possible to resect the cyst without the need for a large incision in the abdomen. We report a case of a 15-year-old girl who underwent diagnostic laparoscopy for recurring abdominal pain of 2 years' duration. The procedure revealed a huge cyst lying above the omentum with its pedicle rising from the greater curvature of the stomach. The pedicle was noted to have twisted eight times in a clockwise direction. The cyst was resected by laparoscopic means using three trocars. The postoperative course was uneventful. As presented in this case, we believe that a laparoscopic approach is an attractive alternative for the management of omental cystic lesions.

Abdominal Pain↗

PubMed1999

Small bowel perforation caused by a sharp bone: laparoscopic diagnosis and treatment.

Small bowel perforation caused by sharp or pointed foreign bodies rarely is diagnosed preoperatively because clinical symptoms usually are nonspecific and can mimic other surgical conditions such as appendicitis and cecal diverticulitis. We report the case of a 57-year-old man who underwent diagnostic laparoscopy for abdominal pain of unknown etiology. Swelling and erythema were noted in a segment of small bowel in the right lower abdomen. A tiny sharp-pointed object was found penetrating the inflamed portion of the bowel. This foreign body was removed and the perforation immediately repaired under laparoscopic guidance. The postoperative course was uneventful. We believe that in cases of lower abdominal pain with peritoneal irritation, laparoscopy can provide not only a wide field of examination to localize intraabdominal pathology, but in some instances it can aid in case management.

Animals↗

PubMed1999

Laparoscopic appendectomy for ruptured appendicitis.

We conducted a retrospective analysis to assess the feasibility of laparoscopic appendectomy in cases of ruptured appendicitis. Between August 1993 and April 1998, a total of 328 laparoscopic appendectomies were performed in Min-Shen General Hospital. There were 34 cases of pathology-proven ruptured appendicitis. Patients were divided into three groups according to the operative findings: group 1 (10 cases) consisted of patients with a perforated appendix with local peritonitis, group 2 (15 cases) consisted of patients with perforated appendix with diffused peritonitis, and group 3 (9 cases) consisted of patients with abscess formation around the perforated appendix. Three cases in group 3 were converted to laparotomy and were excluded from this study. Mean age (+/- SD) was 30 +/- 15 years in group 1, 39 +/- 23 years in group 2, and 37 +/- 13 years in group 3. Duration of symptoms was longer in group 3 (4.2 +/-1.2 days) than in group 1 (1.8 +/- 1.3 days) and group 2 (2.3 +/- 1.2 days). There was no difference in operation time among groups 1 (52 +/- 10 min), 2 (64 +/- 13 min), and 3 (67 +/- 16 min). The time of flatus passage after operation was similar in the three groups (group 1, 17 +/- 11 hours; group 2, 21 +/- 12 hours; group 3, 24 +/- 8 hours). Hospital stay was significantly shorter in group 1 (3.0 +/- 1.1 days) than in group 2 (5.1 +/- 2.2 days) and group 3 (4.2 +/- 1.2 days). There were no complications and no readmissions. Our results indicate that the laparoscopic approach is feasible for ruptured appendicitis with local or diffuse peritonitis and in selected cases with abscess formation. However, prospective randomized controlled trials are needed to determine which procedure is to be recommended.

Adolescent↗

PubMed1998

Interaction of myocyte enhancer factor 2 (MEF2) with a mitogen-activated protein kinase, ERK5/BMK1.

Myocyte enhancer factor 2 (MEF2) has been implicated in the complex hierarchical regulation of muscle-specific gene expression and differentiation. While the MyoD family members are able to initiate the skeletal muscle differentiation program, whether MEF2 is sufficient in directing skeletal muscle differentiation is still controversial. Furthermore, how MEF2 transactivates its target genes is not fully understood. It has been suggested that the interactions of MEF2 with other factors modify its transcriptional activity. Therefore, the identification of MEF2-interacting factors may be important in understanding the mechanism by which MEF2 activates its target genes. In this study, a mitogen-activated protein kinase (MAP kinase), ERK5/BMK1 was found to interact with MEF2 in a yeast two hybrid screen. The interaction was confirmed by a glutathione S -transferase-pull down assay and a co-immunoprecipitation study indicating that endogenous ERK5 and MEF2 interact with each other in vivo . The interacting domain of MEF2 was mapped to the N-terminus which contains the highly conserved MADS and MEF2 domains. Functionally, ERK5/BMK1 was able to phosphorylate MEF2 in vitro . Furthermore, when cotransfected with ERK5/BMK1, the transactivation capacity of MEF2 was enhanced. These results suggest that the functions of MEF2 could be regulated through ERK5/BMK1.

Amino Acid Sequence↗

PubMed1998

Immunolocalization of transcription factor NF-kappaB in inclusion-body myositis muscle and at normal human neuromuscular junctions.

To investigate whether nuclear factor kappaB (NF-kappaB) is involved in the pathogenesis of inclusion-body myositis (IBM), we immunostained muscle biopsies of eight patients with IBM with specific antibodies against its p50 and p65 subunits. Approximately 70% of IBM vacuolated muscle fibers had strong focal accumulations of both NF-kappaB p50 and p65, which by immunoelectronmicroscopy, localized mainly to clusters of paired-helical filaments (PHFs). Virtually all necrotic fibers, in various muscle biopsies, had diffusely strong p50 immunoreactivity, whereas p65 immunoreactivity was present only in a small subset of necrotic fibers. At all neuromuscular junctions, postsynaptically there was strong p65 but no p50 immunoreactivity. Our data suggest that NF-kappaB plays a role in IBM pathogenesis. Different distributions of NF-kappaB subunits in necrotic fibers and at normal neuromuscular junctions (NMJs) suggests different roles of each subunit in human muscle pathology and physiology.

Humans↗

PubMed1998

Neutralizing epitope mapping of six beta1-bungarotoxin monoclonal antibodies and its application in beta1-bungarotoxin peptide vaccine design.

Twenty three stable monoclonal antibodies (mAbs) against beta1-bungarotoxin (beta1-bgt) were prepared by the hybridoma technique. Seven of the 23 mAbs (mAbs 2, 6, 8, 11, 17, 21 and 22) could inhibit more than 70% of phospholipase A2 activity of beta1-bgt and neutralize the toxin. Six of these neutralizing mAbs (mAbs 2, 6, 8, 17, 21 and 22) recognized continuous epitopes on the A chain of beta1-bgt and the other one (mAb 11) recognized a conformational epitope on the toxin. The continuous epitopes of these six mAbs were mapped using synthetic peptide and proteolytic enzymes. Experimental results indicate that mAb 17 recognized the A-chain residues 31-37; mAbs 2 and 8 recognized residues 46-51; mAbs 21 and 22 recognized residues 91-98; and mAb 6 recognized residue 100-106. The competitive-antibody-binding inhibition experiments showed that the affinity of these neutralizing mAbs to the native beta1-bgt is compatible with synthetic peptides. Furthermore, mice immunized with BSA-conjugated A-chain-peptide sequences A(31-37), A(46-51), A(91-98) or A(100-106) were protected from a high-dose beta1-bgt challenge. Subsequently, the peptide-immunized sera were passively injected into Balb/c mice and a significantly protective effect was also observed. To our knowledge, this study is the first systematic demonstration of multiple neutralizing B-cell epitopes of beta1-bgt, and this study is also the first report of the protective synthetic-peptide vaccine against beta1-bgt challenge.

Amino Acid Sequence↗

PubMed1998

Innervation of the human anterior urethra by the dorsal nerve of the penis.

Previous neuroanatomic studies have demonstrated that branches of the dorsal nerve of the penis (DNP) innervate the anterior urethra. This study utilized electrodiagnostic techniques to confirm this finding. Electrical stimulation of the urethra resulted in responses recorded in the main trunk of the DNP, and responses were recorded from the urethra following stimulation of the DNP. A bulbocavernosus reflex was evoked after urethral stimulation. Urethral afferent impulses have a role in reflex ejaculatory function.

Adult↗

PubMed1998

Peripheral distribution of the human dorsal nerve of the penis.

PURPOSE: The integrity of the dorsal nerve of the penis is crucial for normal erectile and ejaculatory function. To our knowledge a description of this nerve along the phallus has not been formally described. We illustrate the distribution of the dorsal nerve of the penis to the penile shaft, anterior urethra and glans. MATERIALS AND METHODS: Neuroanatomical dissections were performed on 28 cadaver penis specimens. Electrodiagnostic testing was conducted on 10 healthy male subjects to confirm the anatomical findings. RESULTS: The dorsal nerve of the penis consists of 2 populations of axons, one to innervate the penile shaft and urethra, and the other to innervate the glans. Stimulation of the urethra resulted in responses recorded in the main trunk of the dorsal nerve of the penis and stimulation of the nerve evoked responses within the urethra. Bulbocavernosus muscle contraction was elicited following urethral stimulation. CONCLUSIONS: Urethral innervation by the dorsal nerve of the penis supports the view that urethral afferent impulses are a component of reflex ejaculatory activity. The pattern of glanular innervation by the dorsal nerve of the penis identifies the glans as a sensory end organ for sexual reflexes. The undulating character of the dorsal nerve of the penis is a mechanism by which the nerve can accommodate to significant changes in penile length with erection. Electrodiagnostic studies of the dorsal nerve of the penis should be modified to consider the anatomical findings.

Adult↗

PubMed1998

Differential tyrosine phosphorylation/activation of oncogenic proline-directed protein kinase F(A)/GSK-3alpha in well and poorly differentiated human prostate carcinoma cells.

Computer analysis of protein phosphorylation site sequences revealed that transcriptional factors and viral oncoproteins are prime targets for regulation of proline-directed protein phosphorylation, suggesting an association of the proline-directed protein kinase (PDPK) family with neoplastic transformation and tumorigenesis. In this report, an immunoprecipitate activity assay of proline-directed protein kinase F(A)/glycogen synthase kinase-3alpha (PDPK F(A)/GSK-3alpha) has been optimized to demonstrate significantly increased (p < 0.01) activity in poorly differentiated human prostate carcinoma PC-3 cells (55.5+/-3.8 units/mg) when compared to well-differentiated LNCaP cells (28.1+/-2.3 units/mg). Immunoblotting analysis revealed that increased activity of this PDPK in PC-3 cells is due not to overexpression of the protein, but to enhanced tyrosine phosphorylation of the kinase. When treated with genistein (a protein tyrosine kinase PTK inhibitor), the enhanced tyrosine phosphorylation/activation of the kinase in PC-3 cells can be blocked. Conversely, when treated with vanadate (a protein tyrosine phosphatase PTP inhibitor), the phosphotyrosine content of PDPK F(A)/GSK-3alpha in LNCaP cells can be promoted to the level of PC-3 cells. In sharp contrast, the PTK inhibitor has little effect on the tyrosine phosphorylation level of the kinase in LNCaP cells, whereas the PTP inhibitor has little effect on the tyrosine phosphorylation level of the kinase in PC-3 cells. Taken together, the results provide initial evidence that the tyrosine phosphorylation/activation levels of this oncogenic PDPK can be differentially regulated in well- and poorly differentiated prostate carcinoma cells.

Amino Acid Sequence↗

PubMed1998

Neuroanatomy of the penile portion of the human dorsal nerve of the penis.

OBJECTIVE: To determine the distribution of the dorsal nerve of the penis (DNP), the principal somatosensory nerve innervating the phallus, along the penile shaft and within the glans penis. MATERIALS AND METHODS: The DNP was dissected in human autopsy specimens, using low magnification, following the course of the nerve from the symphysis pubis into the glans penis. RESULTS: The shaft and glans were innervated by separate populations of axons. The lateral and ventral portions of the penile shaft were innervated by branches arcading from the dorsal midline radiating toward the ventral surface. These branches were very variable and some were seen to penetrate the corpus spongiosum. The axons innervating the glans were constant in a dorsal, midline location along most of the penile shaft, and once within the glans, there was abundant branching. Undulations in the nerves were noted along the penile shaft. CONCLUSIONS: The lateral arcading branches of the DNP provide a sensory pathway on the ventral and lateral penile shaft, and the termination of the fibres at the corpus spongiosum is consistent with pudendal innervation of the penile urethra. The distinct pattern of innervation of the glans emphasizes the role of the glans as a sensory structure. These findings may aid in planning penile surgical procedures.

Aged↗

PubMed1998

Nitric oxide-induced oxidative stress in autosomal recessive and dominant inclusion-body myopathies.

Autosomal-recessive and autosomal-dominant hereditary inclusion-body myopathies are severe, progressive muscle diseases, characterized pathologically by vacuolated muscle fibres containing paired helical filaments. We immunostained muscle biopsy specimens from quadriceps-sparing autosomal-recessive and autosomal-dominant inclusion-body myopathy subjects, disease-control subjects and normal patients, utilizing isoform-specific antibodies against the neuronal and inducible forms of nitric oxide synthase, and antibodies against nitrotyrosine. Approximately 75% of the vacuolated muscle fibres in all recessive and dominant inclusion-body myopathy patients contained inclusions strongly immunoreactive with antibodies against neuronal and inducible nitric oxide synthase which, by immunoelectron microscopy, were colocalized to clusters of tubulofilaments (previously shown, by us, to be paired helical filaments). Strong nitrotyrosine immunoreactivity was in the form of multiple dots and large granular patches, which ultrastructurally did not immunolocalize to tubulofilaments. Excess intracellular nitric oxide can combine with superoxide to produce highly toxic peroxynitrite, which can nitrate tyrosines of proteins. The presence of nitrotyrosine is indicative of nitric oxide-induced oxidative stress. Our data suggest that oxidative stress plays a role in the pathogenic cascade of hereditary inclusion-body myopathies.

Genes, Dominant↗