Biomedical subjects

C C Yang

Publications and source records attributed to C C Yang.

At least 127 records · Page 7Linked to original sources

PubMed1998

Characterization of the carcinogen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in cooking aerosols under domestic conditions.

Lung cancer in women is the leading cause of cancer death in Taiwan. Most Chinese women are non-smokers and 60% of female lung cancer patients have adenocarcinomas. Epidemiological data indicate that the incidence of lung cancer among Chinese women may be correlated with cooking fumes. However, the carcinogenic compound(s) in cooking fume aerosols is not defined. In the present study, the cooking aerosols from Chinese stir-frying of fish were prepared under domestic conditions. To determine the mutagenic compounds in the cooking aerosol, mutagens were purified by two steps of high-performance liquid chromatography (HPLC), and their mutagenicity was monitored with Salmonella typhimurium TA98. The mutagen was eluted as a single peak. The chemical structure of the mutagenic fraction of cooking aerosol from frying of fish was characterized by UV spectra and electrospray mass spectrometry. The bacterial indirect-acting mutagenic compound in the cooking aerosol extract was determined to be 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). An amount of 0.25 ng MeIQx/g of meat per min was estimated based on the mutagenic response. These data indicated that significant amounts of MeIQx (268.1 ng/Chinese dish of frying fish) were present in cooking aerosol in a short time. Chinese women spend approximately 1 h preparing meals everyday, thus, they may be exposed to significant amounts of MeIQx from cooking aerosols in the kitchen.

Aerosols↗

PubMed1998

Bladder and rectal doses from external-beam boosts after gynecologic brachytherapy.

PURPOSE: To establish a typical value for radiation doses under pelvic midline shields. MATERIALS AND METHODS: Three methods were used to determine bladder and rectal doses under 5- or 6-half-value layer (HVL) shields for 10- and 24-MV external beams. First, dose was computed with a standard irregular field routine in 25 consecutive patients (aged 35-70 years) with stage IIB or IIIB disease treated with cesium-137 brachytherapy followed by a parametrial external-beam boost. Second, in vivo measurements with a solid-state probe were recorded during the first boost after completion of brachytherapy in each patient. Third, measurements obtained with an ionization chamber in a solid phantom (water-equivalent material) were compared with computed and in vivo results. RESULTS: All three dosimetric methods yielded bladder and rectal doses higher than the commonly assumed 5% of the unshielded primary beam dose. Doses within the shielded volume may be as high as 15% of the unshielded dose. Doses are similar under 5- and 6-HVL midline shields. Often, the actual bladder and rectal doses exceeded the planned dose limits and their corresponding maximum radiation dose tolerance levels. CONCLUSION: Bladder and rectal doses are higher than previously understood. Parametrial boosts may contribute as much as 3.0 Gy to the bladder and rectal doses.

Adult↗

PubMed1998

Dose volume histogram analysis of the gamma knife radiosurgery treating twenty-five metastatic intracranial tumors.

Treating multiple brain metastatic sites in Gamma Knife radiosurgery is not uncommon. Most metastases can be treated with few or even one single shot. Occasionally we have patients returning for retreatment for different intracranial metastatic sites at different times. Dose distribution for these metastases are prescribed locally without considering the previous dose contribution. We present a study which simultaneously calculates the dose distribution of 25 randomly placed shots distributed inside the intracranial region. The Dose Volume Histogram (DVH) is plotted to study the coverage of the tumor sites and normal tissues. We have calculated ten DVH studies and show that 50% of the brain volume receives less than 500 cGy for the maximum tumor dose of 40 Gy, and the dose gradient is extremely steep. This DVH analysis shows that the Gamma Knife radiosurgery is a good treatment modality to control the local tumors while maintaining normal brain function, even for the large number of brain metastasis treated at different times.

Brain↗

PubMed1998

The present and future of poison control center in Taiwan.

The PCC-Taiwan was founded in July 1985 under the auspices of the Department of Health, Executive Yuan, and the Veterans General Hospital-Taipei, Republic of China. It has served a population of 21 million inhabitants on a 24-hours basis. It has also served as a referral center for treating poisoning cases nationwide, a training center for physicians and consultants, and a center for Analytical Toxicology. The average annual volume of telephone inquires to PCC is more than four thousand in recent few years and continue to increase annually. The present and future prospective of the PCC-Taiwan which have to be accomplished are: 1. to propagate public education of poisoning prevention and increase the utility of PCC before events of intoxication, 2. to establish, computerize and improve the database and network of domestic poisonous products or natural toxins, including herbs, 3. to establish an nationwide referral network for severely poisoned patients or cluster poisoning events, 4. to build up a global collaborative work with other poison centers.

Humans↗

PubMed1998

Prolonged severe withdrawal symptoms after acute-on-chronic baclofen overdose.

INTRODUCTION: Baclofen is frequently used to treat muscle spasticity due to spinal cord injury and multiple sclerosis. Baclofen overdose can lead to coma, respiratory depression, hyporeflexia, and flaccidity. An abrupt decrease in the dose of baclofen due to surgery or a rapid tapering program may result in severe baclofen withdrawal syndrome manifesting hallucinations, delirium, seizures, and high fever. Severe baclofen withdrawal syndrome secondary to intentional overdose, however, has not received mention. CASE REPORT: A 42-year-old male receiving chronic baclofen therapy, 20 mg/d, attempted suicide by ingesting at least 800 mg of baclofen. He was found in coma 2 hours postingestion with depressed respirations, areflexia, hypotonia, bradycardia, and hypotension. Treatment with intravenous fluids, atropine, dopamine, and hemodialysis was associated with restoration of consciousness within 2 days but disorientation, hallucinations, fever, delirium, hypotension, bradycardia, and coma developed during the following week. Baclofen withdrawal syndrome was not diagnosed until hospital day 9, when reinstitution of baclofen rapidly stabilized his condition. Oral overdosage of baclofen causes severe neurological and cardiovascular manifestations due to its GABA and dominant cholinergic effects. Severe baclofen withdrawal syndrome is manifest by neuropsychiatric manifestations and hemodynamic instability. Caution should be exercised after a baclofen overdose in patients receiving chronic baclofen therapy.

Adult↗

PubMed1998

Clinical experience in acute overdosage of diphenidol.

BACKGROUND: Diphenidol (Cephadol, Vontrol), an antiemetic agent used in the treatment of vomiting and vertigo, has been reported to cause various adverse effects including drowsiness, hypotension, confusion, hallucination, restlessness, and other antimuscarinic effects. Serious toxic effects might be anticipated after intentional or accidental ingestion. MATERIALS AND METHODS: Retrospective analysis of all case records of the PCC-Taiwan defining diphenidol overdose during 1985-1996. RESULTS: The data of 21 patients with diphenidol overdose were analyzed; 17 were < 3 years old and unintentionally poisoned, in contrast to the suicide attempts by four adults. The average amount of ingestion was 222.5 mg with a range of 25-800 mg. Most patients manifested only transient CNS, cardiovascular, or oculo-facial effects, but four children suffered from severe toxicity after an ingestion of 11.7-80 mg/kg diphenidol. Commonly reported toxicity in diphenidol overdose included facial flush (10), tachycardia, restlessness (6), seizures (4), dyspnea, drowsiness, mydriasis, coma, and fever (3). With supportive therapy, a good recovery was the rule except for one fatality of a 2 1/2-year-old boy who ingested 15 mg/kg diphenidol and presented with recurrent seizures, hypotension, respiratory failure, and coma. CONCLUSIONS: Although not previously reported, accidental diphenidol overdose may result in serious anticholinergic toxicity in children. Treatment is supportive and the therapeutic role of physostigmine in diphenidol poisoning is still unclear.

Adult↗

PubMed1998

The clinical significance of hyperamylasemia in organophosphate poisoning.

OBJECTIVE: Hyperamylasemia with a presumptive diagnosis of acute pancreatitis has been reported following organophosphate poisoning but there are no large-scale studies incorporating more specific diagnostic criteria. METHODS: Retrospective review of the medical records of 159 patients with a diagnosis of organophosphate poisoning over 3 years. Serum amylase, pancreatic amylase, salivary amylase, lipase and cholinesterase levels, and the clinical manifestations were analyzed. RESULTS: Serum amylase data was available for 121 of the 159 study patients. Hyperamylasemia (amylase > or = 360 U/L) was found in 44 patients (36%). Lipase was measured in 28 patients with hyperamylasemia; 9 of 28 had hyperlipasemia (lipase > or = 380 U/L). The finding of hyperamylasemia was closely related to clinical severity and presence of shock. A presumptive diagnosis of painless acute pancreatitis was diagnosed by hyperlipasemia associated with hyperamylasemia, clinical severity, serum LDH, and leukocyte counts. Two patients with presumptive pancreatitis died. Shock, coma, and hypoalbuminemia were the factors predicting fatality. CONCLUSIONS: Hyperamylasemia is frequent in severe organophosphate poisoning. However, hyperamylasemia is not synonymous with acute pancreatitis and pancreatic amylase is not a reliable parameter in the diagnosis of organophosphate-induced pancreatitis due to its low sensitivity and specificity. Lipase assay is indicated in patients with hyperamylasemia for early diagnosis of pancreatitis. Proper image studies and even pathological examination are also needed to confirm the extent of pancreatic injury. With prompt diagnosis and appropriate treatment, a complete recovery can be anticipated unless the patient has otherwise unrelated complications.

Acute Disease↗

PubMed1998

A fatal case of acute ferric chloride poisoning.

Death from ferric chloride poisoning has never been reported in Taiwan. We report a fatality from the suicidal ingestion of ferric chloride solution used as an etching agent for printed circuitry. A 25-y-old woman presented with vomiting after ingestion of 200 ml ferric chloride solution (pH 1.0). She had hypoxemia and severe metabolic acidosis with respiratory alkalosis initially. Three hours after her ingestion she presented with drowsy consciousness, tachycardia, tachypnea and protracted vomiting. Laboratory studies showed leukocytosis, elevated glucose, aspartate aminotransferase, amylase, lactate dehydrogenase, and total bilirubin, coagulation defect and hemolysis. Aspiration pneumonia and vision loss were also noted. Four hours after ingestion cardiopulmonary arrest suddenly occurred after severe vomiting and she expired. Toxicological studies showed marked elevation of serum iron (2440 micrograms/dl); the estimated oral dose of ferric chloride was equivalent to 11.52 g (230 mg/kg) of elemental iron. This patient did not receive deferoxamine due to rapid deterioration and a late diagnosis. Deferoxamine should be given in any symptomatic patient or in the presence of anion gap metabolic acidosis with a history of ferric chloride ingestion.

Acidosis↗

PubMed1998

Light and electron microscopic immunolocalization of presenilin 1 in abnormal muscle fibers of patients with sporadic inclusion-body myositis and autosomal-recessive inclusion-body myopathy.

Sporadic inclusion-body myositis (s-IBM) is the most common progressive muscle disease of older persons. The muscle biopsy demonstrates mononuclear cell inflammation and vacuolated muscle fibers containing paired helical filaments and 6- to 10-nm fibrils, both resembling those of Alzheimer disease brain and Congo red positivity. The term hereditary inclusion-body myopathies (h-IBMs) designates autosomal-recessive or autosomal-dominant disorders with muscle biopsies cytopathologically similar to s-IBM but without inflammation. Vacuolated muscle fibers of both s-IBM and the h-IBMs contain accumulations of several "Alzheimer-characteristic proteins" including beta-amyloid protein and beta-amyloid precursor protein, and their paired helical filaments are composed of phosphorylated tau. We used six well characterized antibodies against several residues of presenilin 1 (PS1) to immunostain muscle biopsies of 12 patients with s-IBM, 5 patients with autosomal-recessive inclusion-body myopathy, and 16 normal and disease controls. Seventy to eighty percent of the vacuolated muscle fibers of both s-IBM and autosomal-recessive inclusion-body myopathy had inclusions that were strongly PS1-immunoreactive, which by immunoelectron microscopy localized mainly to paired helical filaments and 6- to 10-nm filaments. None of the control biopsies had PS1-positive inclusions characteristic of the s- and h-IBM abnormal muscle fibers. Mutations of the newly discovered PS1 gene are responsible for early-onset familial Alzheimer disease (AD), and PS1 is abnormally accumulated in sporadic and familial AD brain. Our study provides the first demonstration of PS1 abnormality in non-neural tissue and in diseases other than AD and suggests that the cytopathogenesis in AD brain and IBM muscle may share similarities.

Adult↗

PubMed1998

Clinical experience with pendimethalin (STOMP) poisoning in Taiwan.

The herbicide pendimethalin (STOMP) shares a similar chemical structure with nitro compounds such as dinitrobenzene, which was previously demonstrated to cause methemoglobinemia in mammals. However, reports on STOMP poisoning in humans are rare. We reviewed 71 STOMP poisoning cases (42 men and 29 women of mean age 43.9 +/- 2.5 y) reported to the Poison Control Center--Taiwan from September 1986 to September 1997 and summarized their clinical manifestations. Two incidences resulted from skin and eye contact. The rest were due to oral ingestion intentionally or accidentally. The average ingestion was 106.1 +/- 13.4 ml. Among them, 20 cases had no symptoms or signs, 38 had mild effects such as nausea, vomiting and sore throat, 7 had effects such as severe retching, hematemesis and seizures. Four patients expired due to also taking other herbicides (mainly organophosphates) and because of inadequate airway management. Adequate ventilation support was the major therapy in salvaging the poisoning cases.

Adult↗

PubMed1998

Acute inductive effects on oncogenic proline-directed protein kinase FA/GSK-3 alpha in NIH 3T3 cells by ethanol and cadmium.

Exposure of NIH 3T3 cells to 375 mM ethanol at 37 degrees C for 20 min could induce a rapid increase in the protein level and cellular activity of oncogenic proline-directed protein kinase FA/glycogen synthase kinase-3 alpha (PDPK FA/GSK-3 alpha), up to approximately 300% of the control level, in a time- and concentration-dependent manner. The maximal inductive effect on PDPK FA/GSK-3 alpha also occurred within 40 min when cells were treated with only 100 mM ethanol. Similarly, exposure of NIH 3T3 cells to 100 microM cadmium for 2 h could induce a rapid increase in the protein level and cellular activity of PDPK FA/GSK-3 alpha, up to approximately 250% of the control level, in a time- and concentration-dependent manner. The maximal inductive effect on this kinase reached within 3 h when cells were treated with only 50 microM cadmium. The results demonstrate that PDPK FA/GSK-3 alpha may not represent a constitutively active/mitogen-inactivated protein kinase as previously conceived. Taken together with the previous report that PDPK FA/GSK-3 alpha is a heat-inducible protein kinase, the results further demonstrate that PDPK FA/GSK-3 alpha may represent a typical cellular stresses-inducible protein kinase subject to early induction by heat, ethanol and cadmium.

3T3 Cells↗

PubMed1998

Cardiac arrhythmia and betel nut chewing--is there a causal effect?

Betel nuts are widely ingested in many countries, including Taiwan. They stimulate various autonomic and CNS reactions, but there have been no reports of cardiac toxicity. We treated 2 patients with cardiac dysrhythmias thought due to betel nut chewing. In case 1, a 44-y-old previously healthy male presented with chest tightness, dyspnea, diaphoresis and palpitation immediately after chewing 1 betel quid. He soon became breathless and died despite immediate cardiopulmonary resuscitation. In Case 2, a 28-y-old man suffered palpitations, epigastralgia, and chest distress following consumption of 4 betel quid. Paroxysmal supraventricular tachycardia was noted and terminated by repeated verapamil administration. The pharmacological properties of betel nuts and the time sequence of these cases raise the possibility of betel nut-induced cardiac dysrhythmias. The number of betel nut chewers in Taiwan continues to increase, suggesting there may be other cases of betel nut-related cardiac toxicities in the future.

Adult↗

PubMed1998

Mitochondrial myopathy with predominant respiratory dysfunction in a patient with A3243G mutation in the mitochondrial tRNA(Leu(UUR))gene.

We report a patient with the A3243G point mutation of mitochondrial DNA (mtDNA) who presented with severe impairment of respiratory function and only mild involvement of limb muscles. This 55-year-old woman had a history of repeated episodes of respiratory failure unexplained by lung disease or central nervous system lesions. Needle electromyography suggested myopathy and muscle biopsy showed many ragged-red fibers. Molecular analysis of mtDNA in blood and muscle cells showed an A3243G point mutation in the tRNA(Leu(UUR))gene; the percentages of mutant mtDNA in blood and muscle cells were 65% and 71%, respectively. These findings suggest that mitochondrial myopathy should be considered as a cause of respiratory failure due to neuromuscular disorders, and that pure myopathy with predominant respiratory dysfunction is one of the heterogeneous phenotypic features associated with the A3243G point mutation of mtDNA.

Female↗

PubMed1998

Concentrated cresol intoxication.

Cresol, a commonly used disinfectant, may cause gastrointestinal corrosive injury, central nervous system and cardiovascular disturbances, and renal and hepatic injury following intoxication. We report a case of acute severe cresol poisoning after a suicide attempt with ingestion of a cresol-soap solution used as a toilet disinfectant. A 44-y-old male was found unconscious after ingesting 300 ml of 50% cresol-soap solution. Endotracheal intubation, gastric lavage and activated charcoal were given immediately which reversed his conscious. He had dermal burns, esophageal and gastric erosion, pneumonia, mixed metabolic acidosis and respiratory aklalosis, renal and liver function impairment, leucocytosis and dark urine. Acute renal failure and hemolysis developed, but he recovered after hemodialysis and intensive supportive care. Urine levels of p-cresol, m-cresol, o-cresol and phenol were respectively 2083, 2059, 125 and 68 mg/g creatinine at 7 h post-ingestion. Though the amount cresol claimed ingested by the patient (150 g) far exceeded the reported lethal dose (30-60 g), and multiple complications developed after massive ingestion, this patient recovered. The renal, pulmonary and hematological effects in this patient might have resulted from the direct toxicity of cresol and its metabolites.

Adult↗

PubMed1998

A case of severe hyperammonemia and unconsciousness following sodium valproate intoxication.

Although valproic acid has gradually gained its popularity in the treatment of various seizure disorders, overdose of valproate is not common. An 18-y-old man with a history of epilepsy controlled by sodium valproate and clonazepam attempted suicide with an ingestion of 45 g sodium valproate. He presented to our service with drowsiness and irritability. Extremely high serum ammonia (623 ug/dL) and elevated serum valproate concentration (575 ug/mL) were found on admission. Several metabolic abnormalities, including hypernatremia, hypocalcemia and metabolic acidosis, as well as, increased serum transaminase levels were also recorded. With supportive measures, he became clear 24 h later and was discharged 6 d after ingestion. Serial follow-up of his serum valproate and ammonia levels disclosed a close relationship between these 2 measurables. After acute overdose of valproic acid, patients usually present with mild and generally reversible depression of the central nervous system. However, impairment of liver function, hyperammonemia, fluid-electrolyte disturbances, coma, seizures, hypotension and even death may occur following valproate overdose. Symptomatic and supportive measures are the mainstay in the treatment of valproic acid overdose. With prompt diagnosis and early institution of treatment, a complete recovery should be anticipated.

Adolescent↗

PubMed1997

The University of Florida frameless high-precision stereotactic radiotherapy system.

PURPOSE: To develop and test a system for high precision fractionated stereotactic radiotherapy that separates immobilization and localization devices. METHODS AND MATERIALS: Patient localization is achieved through detection and digital registration of an independent bite plate system. The bite plate is made and linked to a set of six infrared light emitting diodes (IRLEDs). These IRLEDs are detected by an infrared camera system that identifies the position of each IRLED within 0.1 to 0.15 mm. Calibration of the camera system defines isocenter and translational X, Y, and Z axes of the stereotactic radiosurgery subsystem and thereby digitally defines the virtual treatment room space in a computer linked to the camera system. Positions of the bite plate's IRLEDs are processed digitally using a computer algorithm so that positional differences between an actual bite plate position and a desired position can be resolved within 0.1 mm of translation (X, Y, and Z distance) and 0.1 degree of rotation. Furthermore, bite plate misalignment can be displayed digitally in real time with translational (x, y, and z) and rotational (roll, pitch, and yaw) parameters for an actual bite plate position. Immobilization is achieved by a custom head mold and thermal plastic mask linked by hook-and-loop fastener tape. The head holder system permits rotational and translational movements for daily treatment positioning based on the bite plate localization system. Initial testing of the localization system was performed on 20 patients treated with radiosurgery. The system was used to treat 11 patients with fractionated stereotactic radiotherapy. RESULTS: Assessment of bite plate localization in radiosurgery patients revealed that the patient's bite plate could be positioned and repositioned within 0.5 +/- 0.3 mm (standard deviation). After adjustments, the first 11 patients were treated with the bite plate repositioning error reduced to 0.2 +/- 0.1 mm. CONCLUSIONS: High precision stereotactic radiotherapy can be delivered using separate localization and immobilization systems. Treatment setup and delivery can be accomplished in 15 min or less. Advantages compared with standard systems require further study.

Adult↗

PubMed1997

The effect of pharmacologic erection on the dorsal nerve of the penis.

The dorsal nerve of the penis (DNP) is the primary source of afferent somatic input from the penis and is critical in the male sexual functions of erection and ejaculation. Using genitourinary electrodiagnostic techniques, this study was conducted to investigate the effect of pharmacologic erection on the DNP. Three tests were administered, and the changes in the DNP between flaccid, stretched, and erect states were examined. Calculated nerve conduction velocity (cNCV) measurements of the DNP increased with pharmacologic erection because mechanical straightening of the nerve allowed for a more precise measurement of nerve length. The latencies of the cortical evoked response and the bulbocavernosus reflex were not significantly changed with stretch or pharmacologic erection. In the evaluation of impotence, cNCV DNP measurements should be performed on the erect penis.

Adult↗

PubMed1997

Immunolocalization of nitric oxide synthases at the postsynaptic domain of human and rat neuromuscular junctions--light and electron microscopic studies.

Neuronal (n) and inducible (i) nitric oxide synthase (NOS) were immunolocalized at the postsynaptic domain of human and rat neuromuscular junctions (NMJs) by light and electron microscopy. We applied polyclonal and monoclonal antibodies for colocalization with three other synaptic proteins, utilizing double and triple fluorescence labeling, and gold and peroxidase for immunoelectron microscopy. By light microscopy, nNOS and iNOS colocalized with desmin and dystrophin, known postsynaptic components, but not with neurofilament protein, a presynaptic component. By electronmicroscopy, nNOS, but not iNOS, colocalized postsynaptically on the same structures as desmin; iNOS was also postsynaptic, but did not colocalize with desmin immunoreactivity. At the NMJs of Duchenne muscular dystrophy patients, both nNOS and iNOS were strongly immunoreactive. At the NMJs of a patient with myasthenia gravis, nNOS was weaker than in controls. Total denervation of rat sciatic nerve did not cause any decrease of nNOS or iNOS immunoreactivity 7 days thereafter. At 15 days after denervation, there was a gradual decrease of immunoreactivity, and immunoreactivity disappeared 30 days after denervation, corresponding to the ultrastructurally detectable disorganization of the postsynaptic region. This seems to be the first combined light and electron microscopic description of the postsynaptic localization of nNOS and iNOS at human and rat NMJs.

Adolescent↗