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Biomedical subjects

C S Chang

Publications and source records attributed to C S Chang.

At least 73 records · Page 4Linked to original sources

Unusual dilatation of Virchow-Robin spaces: case report.

Virchow-Robin spaces normally surround the perforating arteries that enter the brain. These spaces are a well-defined sites where immunological reactions take place and they may have implications in the pathogenesis of a number of neuropathological conditions. We present the case of a 52-year-old woman who had a history of complex partial seizures for 30 years. Her routine neurological examinations and mini-mental tests had normal results. Magnetic resonance images of this patient revealed unusual widening of the Virchow-Robin spaces up to 1.5 cm in diameter along the perforating medullary arteries in the white matter, more so in the left hemisphere. Although it has been concluded that these large spaces are a phenomenon of the normal aging brain and are unrelated to neurological diseases, our patient had had epileptic seizures for 30 years. The large Virchow-Robin spaces of our patient might have been an incidental radiologic finding. Their pathogenesis remains unclear, and their possible clinical relationship to epilepsy deserves further pathological studies.

Blood Vessels↗

Nitro-polycyclic aromatic hydrocarbon contents of fumes from heated cooking oils and prevention of mutagenicity by catechin.

According to earlier studies, fumes from cooking oils were found to be mutagenic and several polycyclic aromatic hydrocarbons (PAHs), (benzo(a)pyrene (B(a)P), benz(a)antracene (B(a)A), and dibenz(a,h)anthracene (DB(ah)A)) were identified. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and nitro-polycyclic aromatic hydrocarbons (NPAHs) were extracted from the samples and identified by HPLC chromatography. Extracts from three cooking oil fumes contained 1-nitropyrene (1-NP) and 1,3-dinitropyrene (1,3-DNP). Concentrations of 1-NP and 1,3-DNP were 1.1 +/- 0.1 and 0.9 +/- 0.1 micrograms/m3 in fumes from lard oil, 2.9 +/- 0.3 and 3.4 +/- 0.2 micrograms/m3 in soybean oil, 1.5 +/- 0.1 and 0.4 +/- 0.1 micrograms/m3 in peanut oil, respectively. The preventive effect of three natural antioxidants (gamma-tocopherol (TOC), lecithin (LEC), and catechin (CAT)) for the reduction of mutagenicity and amounts of PAHs and NPAHs of fumes from cooking oils were evaluated. Mutagenicity of cooking oil fumes occurred, and the concentration of B(a)P were significantly reduced (p < 0.05), by adding CAT into cooking oils before heating. B(a)A, DB(ah)A, and two NPAHs were not detected when the concentration of CAT was 500 ppm in all three cooking oil fumes. These results indicate that fumes of cooking oils contained PAHs and NPAHs that may be a risk factor for lung cancer among cooks and the carcinogens could be reduced by adding the natural antioxidant, catechin.

Antimutagenic Agents↗

Evidence for sulfate modification of H-2Dd on N-linked carbohydrate(s): possible involvement in Ly-49A interaction.

Murine class I molecules are ligands for Ly-49 molecules, a family of regulatory receptors expressed on murine NK cells. Since soluble sulfated mono- and polysaccharides interfere with the interaction of Ly-49A, a C-type lectin, and its class I ligand, Dd, it is possible that the oligosaccharides on class I molecules are sulfated and participate in Ly-49A binding. In this report, we show that H-2Dd expressed by activated T cells and various tumor cell lines is sulfated, as demonstrated by immunoprecipitation of Dd following Na235SO4 labeling. The 35SO4(-2) label on Dd expressed by a representative tumor cell, NZB1.1, is removed by peptide N-glycosidase F, but is resistant to endoglycosidase H treatment, indicating that the sulfate group is located on mature N-linked oligosaccharides. Two-dimensional SDS-PAGE analysis revealed that all major mature glycosylation variants of the Dd expressed by NZB1.1 are sulfated. Sodium chlorate, a potent inhibitor of ATP-sulfurylase, which prevents the formation of the sulfate donor, 3'-phosphoadenosine 5'-phosphosulfate, inhibited metabolic sulfation of Dd. NZB1.1 binds isolated Ly-49A immobilized on solid phase through an interaction by cell surface Dd, since cell adhesion was blocked by Abs directed against Dd or Ly-49A. Treatment of the Dd-expressing NZB1.1 tumor cells with sodium chlorate reduced their ability to bind immobilized Ly-49A, particularly when Ly-49A density was limiting. These results provide evidence for sulfation of H-2Dd oligosaccharide moieties, and suggest a role for this posttranslational modification in the interaction of Dd with Ly-49A.

Animals↗

Antibody to a Helicobacter pylori species specific antigen in patients with adenocarcinoma of the stomach.

This study attempted to identify a possible antibody response to Helicobacter pylori, which is associated with patients with adeno-carcinoma of the stomach. By using proteins of H. pylori as the antigen, pooled sera from gastric cancer and non-cancer patients were used as the first antibody for Western blot analysis. Antibody responses to a 26 kD secreted protein were observed in pooled cancer sera, but not in pooled sera from non-cancer patients. The protein was purified, while amino acid sequences revealed that it was a H. pylori species specific protein. The gene of this protein was cloned and a recombinant protein was expressed in E. coli. In addition, an antibody to the recombinant protein was tested in each individual patient using Western blot analysis. None of the forty non-gastric cancer patients were positive for the antibody to the recombinantly expressed 26 kD species specific protein. Meanwhile, six of the twenty four cancer patients tested positive (0/40 vs 6/24, p < 0.01). Results presented herein demonstrate that the species specific protein of H. pylori can be useful in detecting H. pylori associated with adenocarcinoma of the stomach.

Adenocarcinoma↗

Self-oligomerization of NACP, the precursor protein of the non-amyloid beta/A4 protein (A beta) component of Alzheimer's disease amyloid, observed in the presence of a C-terminal A beta fragment (residues 25-35).

NACP, the precursor protein of the non-amyloid beta/A4 protein (A beta) component of Alzheimer's disease (AD) amyloid, also known as alpha-synuclein, was suggested to seed amyloid plaque formation in AD by stimulating A beta aggregation. We have demonstrated that NACP experienced self-oligomerization only in the presence of a modified A beta fragment (A beta25-35) by using dicyclohexylcarbodiimide. This NACP oligomerization, appearing as a discrete ladder on a Tricine SDS-PAGE, was not observed with other A beta peptides such as the reverse peptide A beta35-25 and A beta1-40, indicating this process was specific not only for the C-terminal peptide sequence of the A beta but also for its orientation. It might be, therefore, suggested that the NACP self-oligomers formed only in the presence of a N-terminally truncated A beta peptide could act as a nucleation center for plaque formation during AD development.

Alzheimer Disease↗

Small intestine dysmotility and bacterial overgrowth in cirrhotic patients with spontaneous bacterial peritonitis.

Patients with bacterial overgrowth of the small intestine developed spontaneous bacterial peritonitis (SBP) more frequently than patients without bacterial overgrowth of the small intestine. The objective of this study was to determine whether the incidences of small intestine dysmotility and bacterial overgrowth are higher in cirrhotic patients with a history of SBP than in cirrhotic patients without SBP. Forty cirrhotic patients were enrolled in this study. There were 20 patients with a history of SBP and 20 patients without a history of SBP. Small intestine bacterial overgrowth was diagnosed by breath hydrogen test. Small intestine motility was recorded, by a 3-channel solid-state manometric catheter, for 24 hours. There were no statistical differences in age or sex between the two groups. The Child-Pugh scores in the SBP group were higher than in the non-SBP group (10.5 +/- 2.1 vs. 8.1 +/- 1.9, P < .01). The incidence of bacterial overgrowth of the small intestine was higher in the SBP group than in the non-SBP group (70% vs. 20%, P < .01). The amplitude and duration of migrating motor complex (MMC) activity fronts, as well as the number of clusters per hour, were similar in both groups. However, the frequency of MMC activity fronts was higher in the non-SBP group than in the SBP group (4.8 +/- 2.3/24 hours vs. 3.5 +/- 1.2/24 hours, P < .05). In addition, the MMC velocity was significantly higher in the non-SBP group (8.3 +/- 2.6 vs. 5.3 +/- 2.1 cm/min, P < .01). The incidence of bacterial overgrowth of the small intestine was higher in cirrhotic patients with history of SBP than in those without SBP. Small intestine motility dysfunction was more severe in cirrhotic patients with history of SBP. Impaired motility of the small intestine, causing bacterial overgrowth of the small intestine, may be one of the explanations for recurrent SBP in cirrhotic patients.

Adult↗

Transient increase in the alpha3-isoform of Na,K-ATPase in rat erythroblastic cells.

Using immunoelectron microscopy and isoform-specific antibodies against Na,K-ATPase to study changes in Na,K-ATPase in rat erythroblastic cells during maturation, we unexpectedly observed numerous antigenic sites against the alpha3-isoform in the cytoplasmic phase. There was an increase in the number of alpha3-isoforms after denucleation of the erythroblast. The increase was transient. As the reticulocyte matured into a red blood cell, the number of alpha3-isoforms was reduced drastically. This alpha3-isoform was distributed in a reticular pattern resembling the double layers of endoplasmic reticulum. Western blot analysis confirms the presence of the alpha3-isoform in these cells. X-ray microanalysis of the erythroid series of cells in the bone marrow shows that sodium concentration in the young reticulocyte is higher than that in the nucleated erythroblast. The reason for the transient increase in this pump protein is not clear. It is possible that the increase in sodium concentration in the reticulocyte plays a role in the increase in pump protein synthesis.

Animals↗

Transient impact of hemodialysis on gastric myoelectrical activity of uremic patients.

Upper gastrointestinal discomforts are common in uremic patients. Investigators have stressed the structural, histopathological, and physiological changes in the gastrointestinal tract in the past decades. Few data are available about the electrophysiological changes in the stomach of uremic patients. It is not known whether hemodialysis alters gastric myoelectrical activity. More interestingly, what is the long-term effect? To address these questions, we measured gastric myoelectrical activity before and after hemodialysis in patients with end-stage renal disease on maintenance dialysis treatment. Twenty-one uremic patients with dyspeptic complaints were enrolled in this study. Gastric myoelectrical activity was measured noninvasively using abdominal surface electrodes (electrogastrography). The paired variables obtained before and after hemodialysis were compared statistically. We also compared the difference between two subgroups defined as new hemodialysis patients and chronic hemodialysis patients. We found that there was a significantly lower percentage of normal slow-wave frequency obtained after hemodialysis in comparison with before hemodialysis (fasting state: 49.1 +/- 4.8% vs 68.1 +/- 5.4%, P < 0.01; fed state: 53.8 +/- 6.9% vs 73.4 +/- 4.1%, P < 0.01). In comparing the subgroups, there were no differences between each EGG variable. We concluded that the hemodialysis itself compromised gastric myoelectrical activity in its immediate effect. However, there were no permanent effects regarding gastric myoelectrical activity itself.

Electrocardiography↗

Comparisons of the NACP self-oligomerizations induced by Abeta25-35 in the presence of dicyclohexylcarbodiimide and N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline.

NACP, the precursor protein of the non-amyloid beta/A4 protein (Abeta) component of Alzheimer's disease (AD) amyloid, also known as alpha-synuclein was shown to undergo self-oligomerization only in the presence of a modified Abeta fragment (residues 25 35) by using a relatively hydrophobic coupling reagent, dicyclohexylcarbodiimide (DCCD). Since the oligomerization not only required a relatively high concentration of DCCD but also its efficiency was suppressed even at a slightly basic pH of 7.5, another coupling reagent called N-(ethoxycarbonyl)-2-ethoxy-1,2-dihydroquinoline (EEDQ) was examined in order to make use of this technique to access the functional aspects of NACP in vitro by exploring more accurate and reproducible reaction conditions. The EEDQ also gave rise to the NACP oligomerization only in the presence of Abeta25-35 among the variously modified Abeta peptides. The reagent was about three times more effective than DCCD in terms of its optimal concentration to visualize the oligomers. In addition, its oligomerizing potency was not affected by the basic condition. Although physiological and pathological significance of the NACP self-oligomerization are currently unknown, this dramatic phenomenon and its visualization technique could shed light on the determination of molecular relationships of NACP with various intracellular or extracellular biomolecules related to the pathological conditions of Alzheimer's and Parkinson's diseases.

Amyloid beta-Peptides↗

Acute and chronic arsenic poisoning associated with treatment of acute promyelocytic leukaemia.

Seven relapsed and/or refractory acute promyelocytic leukaemia patients were treated by arsenic trioxide (As2O3). Four patients (4/7, 57%) achieved complete remission after one to three cycles of treatment and the most common acute side-effect was fluid retention (in six patients, 86%), including weight gains and pleuro-pericardial effusions. Evident polyneuropathy compatible with chronic arsenic toxicity was noted in two of the three patients who received As2O3 maintenance therapy and one of them had marked distal muscular atrophy. We suggest that As2O3 may be a useful salvage therapy for relapsed and refractory APL patients, but the acute or chronic arsenic toxicity should be carefully monitored.

Acute Disease↗

Presence of immunoreactive alpha 3 subunit isoform of Na,K-ATPase in mitochondria of kidney.

BACKGROUND: Sodium-potassium-adenosinetriphosphatase (Na,K-ATPase) is the primary membrane enzyme responsible for the reabsorption of sodium ions in the kidney. It is known that in the nephron the major subunit isoforms of Na,K-ATPase are alpha 1 and beta 1. Previous reports on the presence of alpha 2 and alpha 3 isoforms in the kidney were mixed and controversial. METHODS: Techniques of ultrathin cryosectioning and immunoelectron microscopy were used to study the distribution of alpha subunit isoforms (alpha 1, alpha 2, alpha 3) and beta subunit (beta 1 isoform) of Na,K-ATPase in renal tubular cells. Western blot analysis was used to show the presence of the alpha 3 isoform in the extract of kidney mitochondria. RESULTS: We were able to confirm the previous finding that the alpha 1 isoform and the beta 1 isoform were the preponderant isoforms of the alpha and beta subunits of Na,K-ATPase in the basolateral membrane. In addition, we unexpectedly found the presence of the alpha 3 isoform in the mitochondria of rat renal tubular cells. The alpha 2 and alpha 3 isoforms were not observed in either the apical or basolateral membrane. CONCLUSIONS: Both immunoelectron microscopy and Western blot analysis of the rat kidney mitochondria confirm the presence of the alpha 3 isoform of Na,K-ATPase in the rat kidney mitochondria. The function of this enzyme in the mitochondria is not clear at this time.

Adenosine Triphosphate↗

Small-intestinal bacterial overgrowth in patients with liver cirrhosis, diagnosed with glucose H2 or CH4 breath tests.

BACKGROUND: Small-intestinal bacterial overgrowth (SIBO) has been considered a predisposing factor of spontaneous bacterial peritonitis in cirrhotic patients by bacterial translocation or hematogenous spread during spontaneous bacteremia. We investigated 45 cirrhotic patients and 28 healthy subjects to assess the prevalence of SIBO and its relationship with the severity of liver dysfunction and the presence of ascites. METHODS: Bacterial overgrowth was measured by the glucose hydrogen and methane breath test. RESULTS: SIBO was documented in 16 (35.6%) of the 45 cirrhotic patients and in 1 (3.6%) of the 28 healthy controls. The prevalence of SIBO was significantly higher in patients with Child-Pugh class B or C (50%) than in those with class A (19%) and had no relationship with the presence or absence of ascites. CONCLUSIONS: We conclude that the prevalence of SIBO in cirrhotic patients is approximately 35.6% and that it is related to the severity of liver disease. There was no difference among various causes of cirrhosis, such as viral, alcoholic, or idiopathic.

Adult↗

Effect of cisapride on gastric dysrhythmia and emptying of indigestible solids in type-II diabetic patients.

BACKGROUND: Abnormal gastric slow-wave frequencies have been observed in diabetic gastroparesis. To evaluate the effect of cisapride on gastric dysrhythmia and emptying of indigestible solids, 20 type-II diabetic patients with symptoms suggestive of gastroparesis were enrolled in this study. METHODS: Cutaneous electrogastrography, gastric emptying of radiopaque markers, and evaluation of upper gastrointestinal symptoms were performed before and after administration of an 8-week course of cisapride. RESULTS: The fasting-state percentages of dominant frequency in normal and tachygastric ranges improved significantly after an 8-week course of cisapride treatment (P < 0.01 and P < 0.05, respectively). The post-meal percentages of dominant frequency in the tachygastric range also improved significantly after cisapride treatment (P < 0.05). The upper gastrointestinal symptoms score decreased significantly, and gastric emptying of radiopaque markers also increased significantly after 8 weeks of cisapride treatment (P < 0.01). CONCLUSIONS: In conclusion, this study showed that cisapride can improve gastric dysrhythmia during both fasting and post-meal phases in patients with diabetic gastroparesis. In addition, upper GI symptoms and gastric emptying of indigestible solids may also show significant improvement after 8 weeks of cisapride treatment.

Blood Glucose↗

Vacuolating toxin gene polymorphism among Helicobacter pylori clinical isolates and its association with m1, m2, or chimeric vacA middle types.

BACKGROUND: Helicobacter pylori vacuolating cytotoxin encoded by vacA plays an essential role in H. pylori-related pathogenesis. Specific vacA alleles are believed to be associated with increased virulence. Association among vacA polymorphism, vacA middle genotypes, and various H. pylori-related diseases was thus investigated. METHODS: Eighty-nine isolates from patients with various gastrointestinal diseases were examined for restriction fragment length polymorphism (RFLP) of the 2.0-kb polymerase chain reaction-amplified vacA middle region. Further genetic heterogeneity was assessed with ureA-ureB RFLP. RESULTS: Twenty-eight distinct vacA RFLPs were seen among 89 isolates. Each pattern was associated with one specific vacA middle genotype. The association of specific RFLPs with certain clinical manifestations was noted among six common groups. Further RFLP analysis of the 2.4-kb ureA-ureB segment from isolates in four popular vacA RFLPs showed high genetic variation. CONCLUSIONS: The vacA genetic polymorphism may be associated with different gastrointestinal diseases.

Bacterial Proteins↗

Electrogastrographic study of the effect of transcatheter arterial chemoembolization on gastric myoelectric activity.

BACKGROUND: Transcatheter arterial chemoembolization (TACE) of the hepatic artery is frequently used in the treatment of inoperable hepatocellular carcinoma (HCC). TACE causes not only effective tumor tissue necrosis in patients with hepatoma but also adverse effects on extrahepatic abdominal organs. There are no published reports on the effect of TACE on the gastric myoelectric activity. In this study, using cutaneous electrogastrography (EGG), we evaluated the effect of TACE on gastric myoelectric activity in patients with HCC. METHODS: A total of 27 patients (24 men and 3 women, aged 22 to 78 years) with hepatoma, admitted for TACE, were included in this study. Furthermore, 28 patients (24 men and 4 women, aged 26 to 75 years), admitted for diagnostic angiography of the liver, served as the control group. Cutaneous EGG was performed before and after TACE or angiography. RESULTS: In the TACE group there were significant changes in dominant frequency (DF) and percentages of DF in the defined normal range, bradygastric range, and tachygastric range on post-meal EGG. On fasting EGG, only the dominant frequency and percentages of DF in the bradygastric range changed significantly. However, there was no correlation between the occurrence of nausea/vomiting and the degree of change in the EGG variables, during both fasting and postprandial states. In the control group there were no significant differences in EGG variables before and after angiography. CONCLUSIONS: TACE can affect gastric myoelectric activity in HCC patients. Nevertheless, the relationship between changes in myoelectric activity and the occurrence of gastrointestinal symptoms needs further investigation.

Antibiotics, Antineoplastic↗

Gastric dysrhythmia in uremic patients on maintenance hemodialysis.

BACKGROUND: Dyspeptic symptoms are common in uremic patients receiving hemodialysis. Investigators have placed emphasis on the changes in histopathology and physiology of the gastrointestinal tract. But not much data about the gastric myoelectric activity are available. The aim of this study was to assess gastric myoelectric activity in uremic patients undergoing hemodialysis. METHODS: Fifty-eight subjects were enrolled. They were assigned to: group I, uremic patients undergoing hemodialysis with dyspeptic complaints (n = 20); group II, non-uremic patients with matched dyspeptic complaints (n = 20); and group III, healthy volunteers without dyspeptic complaints (n = 18). Gastric myoelectric activity was measured with abdominal surface electrodes in each person. Patients in group I were measured twice, before (group Ia) and after (group Ib) hemodialysis. The data were compared between the groups. RESULTS: In the prehemodialysis period there was a significantly lower percentage of normal slow-wave frequency when compared with group III (fasting, 66.54%+/-5.39% versus 84.58%+/-3.63%; P < 0.005; fed, 72.25%+/-4.16% versus 89.06%+/-2.57%; P < 0.01). In the post-hemodialysis period the difference was even more profound (fasting, 46.52%+/-4.26% versus 84.58%+/-3.63%; P < 0.001; fed, 51.49%+/-6.89% versus 89.06%+/-2.57%; P < 0.005). Yet, when compared with group II, a significant difference existed only in the post-hemodialysis period (fasting, 46.52%+/-4.26% versus 67.30%+/-3.46%; P<0.001; fed, 51.49%+/-6.89% versus 70.41%+/-4.39%; P < 0.01). Another finding is that hemodialysis decreased the gastric myoelectric activity after hemodialysis (fasting, 66.54%+/-5.39% versus 46.52%+/-4.26%; P < 0.001; fed, 72.25%+/-4.16% versus 51.49%+/-6.89%; P < 0.005). CONCLUSIONS: Uremic patients undergoing hemodialysis have impaired gastric myoelectric activity. Interestingly, hemodialysis seems to cause deterioration in gastric myoelectric activity.

Adult↗

p53 alterations in betel quid- and tobacco-associated oral squamous cell carcinomas from Taiwan.

Alterations of p53 have been explored in Taiwanese oral squamous cell carcinomas (OSCCs) consisting of a betel quid (BQ)/tobacco-related subgroup of 36 subjects and a tobacco-related subgroup of 13 subjects. Mutations in conserved exons were found in 12 tumors. Seven mutations were clustered in a hot-spot region mapped to a region between codons 273-282 in exon 8. The incidence of p53 mutation in BQ/tobacco tumors was 22% (8/36). The frequency of p53 allelic loss (21%, 3/14) in BQ/tobacco tumors approximates to the incidence of mutation. This is the first study demonstrating allelic deletion of p53 in such malignancies. Twenty-four of 43 samples showed positive p53 immunostaining. All tumors harboring mis-sense mutations of p53 in conserved exons exhibited nuclear protein accumulation. The incidence of mutation in conserved exons in BQ/tobacco-associated Asian OSCCs (15%) is significantly different from worldwide OSCCs (46%) related primarily to tobacco consumption (P=0.00001).

Adult↗

Osmotic demyelination syndrome with two-phase movement disorders: case report.

Osmotic demyelination syndrome (ODS) is characterized by regions of demyelination throughout the brain, which are most prominent in the pons. This demyelinating disease is associated with electrolyte disturbances and typically occurs in patients who are alcoholic or malnourished. Movement disorders are not frequently recognized in patients with ODS. This report describes a 22-year-old woman with ODS after correction of profound hyponatremia. The main neurologic symptom was two-phase movement disorder. First, she had acute onset dystonia, then the movement disorder transformed to generalized rigidity and tremors in the delayed second phase. Magnetic resonance imaging in the first phase revealed demyelinating lesions in the central pons, bilateral thalami and basal ganglia. In the second phase, the previous myelinolysis had been partially resolved. The clinical course of the two-phase movement disorder did not correlate with the resolving feature of neuroradiologic findings. During the second-phase movement disorder, the patient had a good response to propranolol and trihexyphenidyl.

Adult↗