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Biomedical subjects

Y C Chang

Publications and source records attributed to Y C Chang.

At least 271 records · Page 15Linked to original sources
PubMed1991

Esterase D and retinoblastoma gene loci are tightly linked to Wilson's disease in Chinese pedigrees from Taiwan.

Wilson's disease (WD) is a rare autosomal recessive disorder and has been mapped to the long arm of chromosome 13 (q14.1). We have analyzed the segregation of esterase D (ESD) and retinoblastoma (RB) gene loci in ten families of Chinese WD subjects living in Taiwan. The polymorphic information content (PIC) for ESD and RB was 0.18 and 0.31, respectively. We confirmed a tight linkage between these loci and WD with a lod score of 3.33 by multipoint linkage analysis. The data from this limited number of pedigrees also suggested the following order: centromere-WD-RB-ESD or centromere-ESD-RB-WD. ESD in conjunction with RB polymorphism would be useful in prenatal and presymptomatic diagnosis, as well as in carrier detection in informative pedigrees.

Alleles↗
PubMed1991

The effect of iohexol on brainstem auditory evoked potentials. A prospective study on 30 patients.

A prospective study was made to evaluate the effect of intrathecal injection of iohexol on brainstem auditory evoked potentials (BAEP) following myeloradiculography, in order to assess its neurotoxicity. Thirty patients who received contrast medium via the lumbar route for myeloradiculography (cervical level = 25 patients, lumbar level = 5 patients) had BAEP examinations before, 2 h and 24 h after myelography. No statistically significant prolongation of absolute and interpeak latencies was found between premyelographic and postmyelographic records. Low incidence (20%) of insignificant clinical adverse effect following myelography was also noted in the same group of patient.

Adolescent↗
PubMed1991

Traumatic sinus of Valsalva fistula.

Two rare cases of nonpenetrating trauma-induced fistula from the right sinus of Valsalva to the right heart chambers are reported. Both were diagnosed preoperatively and operated on successfully. A transverse tear was found in the right sinus of Valsalva, just below the right coronary ostium, in both patients. The ragged inlet and a rough fistula tract were noted during operation. The tears were closed with direct sutures or with a Dacron patch. Coronary artery bypass grafting was needed in 1 patient. The results of operation were excellent.

Adult↗
PubMed1991

Attenuation of ischemia-reperfusion injury of the liver in dogs by cyclosporine. A comparative study with allopurinol and methylprednisolone.

The effects of pretreatment with cyclosporine, allopurinol, or methylprednisolone on ischemia-reperfusion injury of the liver were investigated. A total of 32 adult mongrel dogs that received one of the pretreatments were divided into four groups and were subjected to 90 min liver ischemia. Serum activities of aspartate aminotransferase (s-AST) and lactate dehydrogenase, (s-LDH) as well as animal survivals were used as indicators of liver injury. The elevation of both s-AST and s-LDH was significantly suppressed by pretreatment with cyclosporine as much as by allopurinol. However a significant improvement in animal survival was obtained only in the cyclosporine-pretreated group. Pretreatment with methylprednisolone did not affect either the activities of s-AST and s-LDH or animal survivals when compared with the control group. These data suggest that cyclosporine is a potent protector against ischemic liver injury--as effective as allopurinol or methylprednisolone. Although the precise mechanism of the effect of cyclosporine on liver ischemia still remains unknown, these observations may be of use in liver transplantation.

Allopurinol↗
PubMed1991

Beneficial effect of cyclosporine pretreatment in canine liver ischemia. Enzymatic and electronmicroscopic studies.

The effect of cyclosporine on hepatic ischemia was investigated. Hepatic ischemia was produced for 90 min in mongrel dogs. Experimental dogs were divided into three groups as follows: group A (control group), group B (CsA pretreatment group), group C (CsA posttreatment group). CsA was administered at a dose of 10 mg/kg body weight/day for 3 days in the pre- or postoperative period. Survival rates were 61.5% in group A, 84.6% in group B, and 30.8% in group C. Enzymatic activity such as aspartate aminotransferase and lactate dehydrogenase was highest in group C, lowest in group B, and intermediate in group A. Opposite results were obtained for serum albumin concentrations. The mechanisms of the effect was investigated using a 60-min hepatic ischemia model. Serum levels of beta-glucosidase and beta-galactosidase in group B were lower than those in group A and group C. Electronmicroscopic specimens taken at 16 h after 60-min hepatic ischemia demonstrated that the extent of ischemic injury was mildest in group B. The present study demonstrated a beneficial effect on hepatic ischemia of CsA administered for 3 days prior to the ischemia. One of the mechanisms for this beneficial effect could be the stabilization of lysosomal membranes. These results suggest that CsA should be administered to a donor before organ harvesting for liver transplantation because of this beneficial effect.

Animals↗
PubMed1991

Abscisic Acid Negatively Regulates Expression of Chlorophyll a/b Binding Protein Genes during Soybean Embryogeny.

The levels of abscisic acid (ABA) during embryogenesis in the soybean (Glycine max) cultivar Dare were quantitated. An increase in the quantity of ABA per cotyledon was correlated with a decrease in the chlorophyll a/b binding (Cab) protein gene mRNA population. Soybean cotyledons were cultured in vitro in the presence or absence of ABA. Quantitation of cotyledonary ABA levels and Cab mRNA levels indicated that the application of 5 x 10(-5) molar and 5 x 10(-6) molar exogenous ABA decreased Cab mRNA prevalences. S1 nuclease protection experiments demonstrated that exogenous ABA modulated the level of Cab3 mRNA. These data strongly suggest that one of the developmental regulators of Cab gene expression during soybean embryogeny is the plant hormone, ABA; ABA negatively regulates Cab mRNA accumulation.

Journal Article↗
PubMed1991

Solubilization, characterization, and partial purification of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-, quisqualate-, kainate-sensitive L-glutamate binding sites from porcine brain synaptic junctions.

L-[3H]Glutamate binding sites were solubilized from porcine brain synaptic junctions by Triton X-114 in the presence of KCl. The solubilized binding sites bound L-[3H]glutamate reversibly with KD and Bmax values of 1.48 +/- 0.18 microM and 178.2 +/- 15.9 pmol/mg of protein, respectively. These binding sites appeared to be integral membrane glycoproteins, with sugar moieties recognized by wheat germ agglutinin. A 49.3-fold purification of these binding sites was achieved by Triton X-114 solubilization, anion-exchange chromatography, and affinity chromatography using wheat germ agglutinin-Sepharose. The apparent molecular mass of the partially purified binding sites was 620 +/- 50 kDa. L-[3H]Glutamate bound to the solubilized preparation could be effectively displaced by agonists of non-N-methyl-D-aspartate (NMDA) L-glutamate receptors but not by NMDA or alpha-amino-4-phosphonobutyrate. The rank order for the competitive ligands in displacing L-[3H]glutamate was: quisqualate greater than alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid greater than L-glutamate greater than kainate.

Animals↗
PubMed1991

alpha Fetoprotein producing early gastric cancer with liver metastasis: report of three cases.

Three cases of alpha fetoprotein producing early gastric cancer are presented. Liver metastases occurred in all patients shortly after curative gastrectomy and all died within two years. The incidence of liver metastasis was significantly higher than that in alpha fetoprotein negative early gastric carcinoma (p less than 0.001). The incidences of lymph node metastasis and invasion in lymph vessels and veins were also substantially higher in this group of patients. Two radical hepatic resections, including extended right lobectomy, were performed on one patient but the tumour recurred immediately.

Adenocarcinoma↗
PubMed1991

An electrophysiological follow up of patients with n-hexane polyneuropathy.

Electroneurographic (ENeG) and evoked potential (EP) studies were regularly performed on 11 printing workers with n-hexane polyneuropathy after cessation of exposure. At the initial examination, the ENeG studies simulated a demyelinative process. Further slowing of nerve conduction velocity, or further decreasing of action potential amplitude, or both in the follow up ENeG study were found in about half the patients. The motor distal latency did not worsen. Nerve conduction returned to normal earlier in the sensory than in the motor nerves. After the patients had regained full motor capability, conduction velocities in motor nerves were still significantly slowed. These ENeG characteristics correlate with the pathological and pathophysiological changes in experimental hexa-carbon neuropathies. The initial findings from the EP studies indicated a conduction abnormality in the central nervous system (CNS). Delayed worsening occurred in the amplitude of visual EPs in three patients. On serial follow up, the interpeak latency and interpeak amplitude of visual EPs improved little. Residual abnormalities were also found in the interpeak latency of auditory EPs in the brainstem and in the absolute latency of scalp somatosensory EPs from the peroneal nerve. Astroglial proliferation in the CNS probably impedes recovery of the abnormalities in EP.

Adolescent↗
PubMed1991

Plasma lysosomal enzymes after liver transplantation in the pig.

During liver transplantation in the pig, the plasma activities of beta-galactosidase, beta-glucuronidase and beta-glucosidase were elevated as early as 15 min after establishing the hepatic circulation. The enzyme activities peaked at 3 h and returned to the initial level within 2-3 days. However, such substantial alterations were not observed in other enzymes, alpha-mannosidase and alpha-glucosidase. Similar reactions to those of the first three enzymes were found in aspartate aminotransferase and lactate dehydrogenase but with later peaks and slower eliminations. In light of the current study, the serial estimation of acid hydrolases may be useful to discover the extent of tissue injury and also to evaluate the effectiveness of various organ-preservation methods.

Animals↗
PubMed1991

Computed tomography of the brain in patients with serum prolactin levels over 200 ng/ml.

We reviewed the computed tomographic (CT) findings of the sella turcica in 26 patients with a serum prolactin level of over 200 ng/ml. The interval between the dates of CT examination and checking of the serum prolactin level were within 2 months. There were 24 nonpregnant women with a mean age of 30 years and 2 men with a mean age of 28.5 years. None of them were taking medication known to cause an elevation in serum prolactin levels. Surgery was performed on 8 patients with chromophobe adenomas of the pituitary gland: 6 of them were proven to have prolactin-secreting tumors (prolactinomas) after performing a special stain, and the remaining 2 patients, clinically diagnosed as prolactinomas, showed extremely high serum prolactin levels (3,200 and 2,251 ng/ml, respectively). CT studies showed that the height of the pituitary gland in the coronal sections were more than 7 mm in 15 cases (58%) and more than 10 mm in 13 cases (50%); focal bulging of the diaphragma sellae in 16 cases (62%); erosion of the sellar floor in 20 cases (77%); deviation of the pituitary stalk in 19 cases (73%); and abnormal attenuation or enhancement of the pituitary gland in 18 cases (69%). Three patients (12%) showed no evidence of any abnormal CT finding despite a hyperprolactinemic state of over 200 ng/ml. Six histologically proven cases (23%) of prolactinomas and chromophobe adenomas showed radiologic evidence of cavernous sinus invasion. We conclude that patients with a serum prolactin level higher than 200 ng/ml generally show significant changes in the sella turcica in CT.

Adenoma, Chromophobe↗
PubMed1991

CT myelography for differential diagnosis between intramedullary and intradural-extramedullary spinal tumors in the region of the conus medullaris.

We reviewed the myelograms and computed tomographic myelograms of 12 cases of intraspinal tumor with a "cupping sign" on the myelogram in the region of the conus medullaris from 1986 to 1988. There were 5 intramedullary tumors, 4 of them having an exophytic component, and 7 intradural-extramedullary tumors. The myelograms revealed that 4 of the 5 intramedullary tumors showed expansion and the outline of the conus medullaris was irregular, whereas 1 of the tumors showed smooth compression (crescent-shaped) and displacement of the conus medullaris. Six of the 7 intradural-extramedullary tumors showed smooth compression and displacement of the conus medullaris, while 1 of the tumors had caused expansion of the conus medullaris. Complete blockage of the passage of the contrast medium was noted in 3 of the 5 intramedullary tumors, while a partial block was noted in 3 of the 7 intradural-extramedullary tumors. Two of the 7 intradural-extramedulllary tumors showed an extradural tumor component, such as a dumb-bell tumor and a enlarged intervertebral neural foramen. Tumor calcification was noted in 1 of the 7 intradural-extramedullary tumors. Dural ectasia was noted in 2 of the 7 intradural-extramedullary tumors which were later proven to be neurofibromatosis. We conclude that smooth compression (crescent-shaped) and displacement of the conus medullaris, existence of an extradural tumor component, and eroded intervertebral neural foramina favor intradural-extramedullary tumors, while expansion and a conus medullaris with an irregular outline favors intramedullary tumors.

Adolescent↗
PubMed1991

Transcatheter control of intractible gastrointestinal bleeding.

A series of 23 patients with intractible gastrointestinal (GI) bleeding were managed by the transcatheter method. The series included 5 with hemobilia, 8 with upper GI (UGI) bleeding, 5 with lower GI (LGI) bleeding and 5 with variceal bleeding. The etiology of the hemobilia was surgery, or percutaneous transhepatic cholangiography and drainage (PTCD) complicated by various degrees of biliary tract infection. The causes of UGI bleeding included erosive gastritis, gastric and duodenal ulcers, and traumatic duodenal laceration. All 5 LGI bleedings were due to ischemic colitis and all 5 variceal bleedings were due to hyperdynamic portal hypertension from arterio-portal (A-P) shunting for hepatocellular carcinomas (HCC). Intra-arterial vasopressin infusion was performed on 17 (4, hemobilia; 8, UGI; and 5 LGI bleeding) of these 23 cases as initial management. The success rate for vasopressin in hemobilia, UGI and LGI bleeding was 75% (3/4), 38% (3/8), and 60% (3/5), respectively. The overall initial success rate of vasopressin was 52% (9/17). The relatively poor success rate of vasopressin infusion for UGI bleeding was due to ulcers and laceration. The incidence of rebleeding for vasopressin infusion was 22% (2/9) including one case each of UGI and LGI bleeding. Three patients (1 hemobilia and 2 UGI bleeding) among these 17 cases underwent transarterial embolization (TAE) after failure of intra-arterial vasopressin infusion. One of these 23 cases with hemobilia underwent TAE for initial transcatheter control of the GI bleeding. Five cases of active esophageal variceal bleeding, caused by A-P shunting in HCC, were all successfully controlled by TAE.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Identification of efferent-stimulus-responding neurons in the earthworm 3rd segmental nerve by lucifer yellow-CH backfilling.

The objective of the present study was to identify the mechanism for the decreased efferent reflex response recorded extracellularly from an earthworm 3rd segmental nerve after the nerve had been cut. Four neurons which showed a correlated decrease in their efferent responses were identified in the ventral nerve cord by the broken-microelectrode-backfilling method using Lucifer Yellow-CH. The long processes of these neurons extended into the 3rd nerve trunk. Thus, these neurons may represent an efferent link in this complicated reflex arc.

Action Potentials↗
PubMed1991

Effects of hepatitis B virus, alcohol drinking, cigarette smoking and familial tendency on hepatocellular carcinoma.

Independent and interactive effects related to the development of hepatocellular carcinoma were assessed using a community-based case-control study for hepatitis B virus, habitual alcohol drinking, cigarette smoking, peanut consumption and history of hepatocellular carcinoma among the immediate family. All 200 male newly diagnosed hepatocellular carcinoma patients were recruited consecutively through the period of study as the case group from two teaching medical centers in northern and southern Taiwan. Healthy community residents matched one-to-one with cases on age, sex, ethnic group and residential area were selected as the control group. The carrier status of HBsAg and HBeAg was determined by blind radioimmunoassays, and other risk factors were obtained through standardized interviews according to a structured questionnaire. Conditional logistic regression analysis showed a significant association between hepatocellular carcinoma and the carrier status of HBsAg and HBeAg with an odds ratio of 16.7 and 56.5, respectively, for carriers of HBsAg alone and for carriers of both HBsAg and HBeAg. There was a dose-response relationship between cigarette smoking and hepatocellular carcinoma with an odds ratio of 1.1, 1.5 and 2.6, respectively, for those who smoked 1 to 10, 11 to 20 and more than 20 cigarettes a day. A significant association with hepatocellular carcinoma was also observed for the habitual alcohol consumer with an odds ratio of 3.4. Those whose immediate family had a history of hepatocellular carcinoma were more likely to have the disease develop, with an odds ratio of 4.6. However, the frequency of peanut consumption was not significantly associated with hepatocellular carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Phase II study of n-methylformamide (NSC 3051) and spirogermanium (NSC 192965) in the treatment of advanced small cell lung cancer.

Fifty-four evaluable patients with SCLC previously treated with chemotherapy received either N-methylformamide or spirogermanium. There was one partial response to N-methylformamide. The median survival times for patients treated with N-MF and spirogermanium were 11.7 and 12.6 weeks respectively. Five patients treated with N-MF experienced severe toxicity while four patients treated with spirogermanium experienced severe and life-threatening toxicity.

Aged↗