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Biomedical subjects

M L Yang

Publications and source records attributed to M L Yang.

At least 37 records · Page 2Linked to original sources
PubMed1997

Elevated urinary transforming growth factor-beta1 level as a tumour marker and predictor of poor survival in cirrhotic hepatocellular carcinoma.

To assess the clinical relevance of transforming growth factor-beta1 (TGF-beta1) in hepatocellular carcinoma (HCC), urinary TGF-beta1 and serum alpha-fetoprotein (AFP) were determined in 94 patients with cirrhotic HCC, 94 age- and sex-matched patients with cirrhosis alone and 50 healthy adults. TGF-beta1 level in HCC was higher than in cirrhosis alone or in healthy controls (each P = 0.0001). There is an inverse correlation between TGF-beta1 and AFP levels (r = -0.292, P = 0.004). Significantly higher TGF-beta1 level was found in HCC patients with worsening Child-Pugh stages, diffuse HCC, tumour size > 3 cm, multilobular tumour and AFP < or = 20 ng ml(-1). TGF-beta1 level decreased after complete treatment with transcatheter arterial chemoembolization (P = 0.0001). The median survival in HCC patients with raised TGF-beta1 was shorter than those with normal TGF-beta1 (P = 0.018). Multivariate analysis indicated that TGF-beta1 and AFP were significantly correlated with the presence of HCC. In addition, TGF-beta1 could be used as a diagnostic marker for HCC, particularly in tumours with low AFP production. In conclusion, elevated urinary TGF-beta1 level is a tumour marker and predictor of poor survival for cirrhotic HCC.

Adult↗
PubMed1997

Captopril reverses high glucose-induced effects on LLC-PK1 cells partly by enhancing facilitative glucose transporter messenger RNA expressions.

One of the mechanisms of angiotensin-converting enzyme inhibitors in treating diabetic nephropathy is the reversal of renal hypertrophy. Hyperglycemia is the common denominator of all diabetic states. Thus, effects of captopril on high glucose (27.5 mM)-induced alterations in LLC-PK1 cells were studied as related to the facilitative glucose transporters. We found that high glucose (27.5 mM) inhibited mitogenesis and induced hypertrophy in these cells after 48 hours of culture concomitantly with decreased glucose transporter I messenger RNA expression. Captopril (1 mM) reversed the above effects concomitantly with enhancement of glucose transporter I and II messenger RNA expressions. We conclude that decreased expression of glucose transporter I may be associated with increased intracellular glucose and the resultant ill effects. Captopril reversed the above high glucose-induced effects partly by enhancing glucose transporter I and II messenger RNA expressions.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Clinical relevance of transforming growth factor-beta 1 in the urine of patients with hepatocellular carcinoma.

To assess the clinical relevance of transforming growth factor-beta 1 (TGF-beta 1) in the urine of patients with hepatocellular carcinoma (HCC), TGF-beta 1 was measured, by radioimmunoassay, in 140 patients with HCC, 50 cirrhotic patients, 30 patients with chronic active hepatitis, and 50 healthy controls. The results indicate that there were significantly increased urinary TGF-beta 1 levels in patients with HCC. Raised TGF-beta 1 levels were associated, in a dose-related fashion, with increased risk for development of HCC (odds ratio, 1.05, 95% confidence interval, 1.03-1.07). HCC patients with raised TGF-beta 1 levels had shorter survival than those with normal TGF-beta 1 levels (p = 0.038). TGF-beta 1 levels decreased after successful anticancer therapy (p < 0.0001). There was an inverse correlation between TGF-beta 1 and serum alpha-fetoprotein (AFP) (r = -0.199, p < 0.04). Receiver operating characteristics (ROC) curve analysis indicated that parallel determination of TGF-beta 1 and AFP significantly increased the sensitivity and diagnostic accuracy, with a high specificity. In conclusion, raised urinary TGF-beta 1 was associated with HCC development. It is a predictor of poor prognosis, and a tumor marker for diagnosis and therapeutic follow-up of HCC.

Adult↗
PubMed1997

Effects of high glucose culture on EGF effects and EGF receptors in the LLC-PK1 cells.

We have shown that epidermal growth factor (EGF) may be important in diabetic renal hypertrophy. Since EGF is the most potent mitogen for the proximal tubule, it may be relevant to the cellular hyperplasia component in diabetic nephropathy. In order to further clarify the possible alterations of mitogenic effects of EGF on cultured renal cells in hyperglycemic states, the effects of high glucose culture on EGF-induced events and EGF receptors were studied in LLC-PK1 cells with equimolar mannitol being used as an osmotic control. The results showed that high glucose dose-dependently decreased mitogenesis while increasing cellular hypertrophy in LLC-PK1 cells. The dose-response curve of EGF-induced mitogenesis was similar in both normal (11 mM) and high (27.5 mM) glucose cultures. Meanwhile, EGF receptor number and affinity were not changed by high glucose in these cells. Furthermore, mannitol mimicked the growth-suppressive (but not hypertrophic) effects of high glucose cultures. Based upon these findings, we conclude that high glucose did not alter the mitogenic effects of EGF on the LLC-PK1 cells. This was associated with unchanged EGF receptor characteristics. Thus, concurrent with our previous studies, we speculate that it is the increased local EGF level, rather than an increased renal sensitivity to it, which is associated with hyperglycemic tubulopathy.

Animals↗
PubMed1997

Acetaminophen poisoning in late pregnancy. A case report.

BACKGROUND: Acetaminophen poisoning is a major cause of hospital admission and has been extensively reviewed. Its occurrence in pregnant women has been reported seldom, and the prognosis has been good except for one case, in which the fetus died. We report on a case of acetaminophen poisoning that resulted in the death of both the mother and the infant. CASE: A 38-year-old woman whose pregnancy was at 31 weeks' gestational age was evaluated for treatment of an acetaminophen overdose. She was admitted more than 26 hours after taking 35 g of acetaminophen. An emergency cesarean section was performed one hour after admission because of acute fetal distress. A grossly normal, 1,620-g, female infant was delivered and had Apgar scores at 1, 5 and 10 minutes of 0, 0 and 1, respectively, despite the initiation of resuscitation immediately following delivery. Acidosis was noted in the mother during the operation; it was followed by acute hepatorenal failure 16 hours after admission. That resulted in the mother's death 40 hours after admission. The infant also died 34 hours after delivery. CONCLUSION: Delays in administering the antidote treatment, N-acetylcysteine, after acetaminophen intoxication significantly increase the risk of mortality in both the mother and infant. The development of acidosis carries a poor prognosis in such patients and may necessitate liver transplantation to save the life of the mother.

Acetaminophen↗
PubMed1997

Linkage analysis of families with autosomal dominant polycystic kidney disease by KG8-CA marker.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic diseases of human. Traditionally, ADPKD is diagnosed by ultrasonography, computed tomography (CT) or magnetic resonance imaging (MRI) of kidneys for the presence of renal cysts. Individuals who carry the defective gene but have not yet developed cysts in kidney may not be diagnosed. Genetic analysis reveals it to be caused mostly by a single-gene disorder of a genetic locus, designated PKD1. Recently, the genetic locus involving PKD1 has been identified on chromosome 16p13.3, and has been cloned and completely sequenced. METHODS: A pair of primers, KG8-CA, located between D16S84 and D16S125, was selected and synthesized for the polymerase chain reaction (PCR) to identify individuals who may carry the defective locus. The sequence of KG8-CA primers, was 5'-CTCCCAGGGTGGAGGAAGGTG-3' and 5'-GCAGGCACAGCCAGCTCCGAG-3'. PCR products were analyzed in denaturing condition, using gel containing 8% acrylamide and 7M urea. Autoradiography was carried out to interpret the results. RESULTS: Four Chinese families with history of ADPKD showed different DNA patterns in individuals with ADPKD and in normal individuals. Among the members in four families with history of ADPKD, every individual shared a common DNA band, suggesting that this band was derived from normal PKD1 allele. On the other hand, individuals diagnosed to have ADPKD showed one or two additional DNA bands which migrated differently from the common DNA band and should therefore be derived from defective ADPKD allele. Previous studies have shown that the ADPKD allele is highly polymorphic, as was evident in these family studies. CONCLUSIONS: Among the members from these four families, some were clinically normal and had DNA pattern that was typical to patients with ADPKD. These individuals might carry the defective PKD1 allele but have not yet developed the ADPKD symptoms. Therefore, the method described in this study has diagnostic values for pre-symptomatic individuals as well as for patients already diagnosed with ADPKD.

Female↗
PubMed1996

Effect of an pyruvate-based peritoneal dialysis solution on the pH of a residual peritoneal dialysis fluid.

An acidic (pH 5.2) pyruvate-based peritoneal dialysis solution or an equally acidic lactate-based counterpart was added to a residual fluid (i.e., peritoneal effluent) obtained from each of 6 continuous ambulatory peritoneal dialysis patients. It was found that the residual fluids were able to raise the pH of the resultant residual fluid/peritoneal dialysis solution mixture to a higher level in the case of the pyruvate-based solution than in the case of the lactate-based one.

Ascitic Fluid↗
PubMed1996

Captopril reverses high-glucose-induced growth effects on LLC-PK1 cells partly by decreasing transforming growth factor-beta receptor protein expressions.

Transforming growth factor beta (TGF-beta) may be important in the pathogenesis of diabetic nephropathy, and captopril is effective in treating this disorder. However, the mechanisms of this therapeutic effect as related to TGF-beta and its receptors are not known. Thus, the effects of captopril on cellular growth, TGF-beta 1, and TGF-beta receptors were studied in LLC-PK1 cells cultured in normal (11 mM) or high glucose (27.5 mM). This study found that glucose dose-dependently inhibited cellular mitogenesis while inducing hypertrophy in these cells at 72 h of culture, concomitantly with enhanced TGF-beta 1 messenger RNA (mRNA) and TGF-beta receptor Types I and II protein expressions. Captopril dose-dependently (0.1 to 10 mM) increased cellular mitogenesis and inhibited hypertrophy in these cells. Moreover, captopril also decreased TGF-beta receptor Types I and II protein expressions dose-dependently. However, TGF-beta 1 mRNA was not affected by captopril. It was concluded that high glucose decreased cellular mitogenesis while increasing hypertrophy concomitantly with increased TGF-beta 1 mRNA and TGF-beta receptors in LLC-PK1 cells. Captopril can reverse high-glucose-induced growth effects by decreasing TGF-beta receptor protein expressions.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Alterations of serum lipid levels and their biological relevances during and after pregnancy.

In normal pregnancy, all women displayed a significant elevation of serum triglyceride (TG), total cholesterol (TC), low density cholesterol (LDL-C) and high density cholesterol (HDL-C) during parturition. To study the quantitative changes in serum levels of lipids and their biological relevances during and after pregnancy, blood samples were collected from 62 normally pregnant women throughout gestation and 6 to 12 weeks postpartum. Compared with 184 nonpregnant control subjects, TG, TC, LDL-C and HDL-C were significantly elevated during the second and third trimesters of pregnancy but dropped sharply after pregnancy. To further understand the effect of pregnancy on other metabolic parameters, we compared the relative levels of apolipoproteins such as apolipoprotein A-I (apoA-I) and apolipoprotein B (apoB), lipoprotein (a) (Lp(a)) and blood sugar during and after pregnancy. We found that apoB concentration progressively increased with advancing gestation, while the levels of apoA-I, Lp(a) and blood sugar were independent of gestation process. The physiological significance of hyperlipidemia during pregnancy is also discussed in this study.

Female↗
PubMed1995

Effects of early cysteamine therapy on thyroid function and growth in nephropathic cystinosis.

Primary hypothyroidism is a known complication of nephropathic cystinosis, a lysosomal storage disorder characterized by renal failure as well as deterioration of other organs. The drug cysteamine depletes lysosomes of cystine and helps preserve renal function and enhance growth in cystinosis patients. To determine whether cysteamine also prevents hypothyroidism, we retrospectively divided 101 patients into group A (n = 28; well treated), group B (n = 26; partially treated), and group C (n = 47; poorly treated). Lifetable analysis indicated a significantly higher probability of remaining free of L-T4 replacement in group A vs. group B (P = 0.09) or group C (P = 0.004). Cysteamine therapy also improved mean height z-scores (-2.17 in group A, -3.04 in group B, and -4.07 in group C) and reduced the bone age deficit (i.e. chronological age minus bone age) by 1.5 yr for every 10 yr of previous cysteamine therapy. We conclude that in addition to its other salutary effects, oral cysteamine therapy helps prevent hypothyroidism and enhances growth in patients with nephropathic cystinosis.

Adolescent↗
PubMed1994

Urinary epidermal growth factor receptor-binding growth factors in patients with cancers of the digestive tract.

To investigate whether the urinary excretion of epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) is increased in patients with cancer of the digestive tract, EGF and TGF-alpha were determined in 109 cancer patients and 40 healthy controls. Excluding EGF in hepatocellular carcinoma (HCC) and TGF-alpha in pancreatic cancer, both growth factors in each cancer group were significantly higher than in the control group. A receiver operating characteristic curve and likelihood ratio were applied to obtain the best diagnostic efficiency. Both EGF and TGF-alpha had high specificity (100%) in all cancer group. The high sensitivity of EGF in gastric cancer (100%) and metastatic liver cancer (93.3%), moderate sensitivity of TGF-alpha in metastatic liver cancer (86.6%), colon cancer (80.0%), and HCC (61.7%) suggested that they might be helpful in identifying these cancers. In conclusion, urinary excretion of EGF and TGF-alpha increased in most cancers of the digestive tract. They may be used as tumor markers.

Adult↗
PubMed1994

Prenatal diagnosis of beta-thalassemic mutations in Chinese by multiple restriction fragment-single strand conformation polymorphism analysis.

A modified approach of polymerase chain reaction (PCR)-based single strand conformation polymorphism (SSCP) has been developed for prenatal diagnosis of beta-thalassemic mutations. In this method, a single PCR product (1,350-bp) is first generated, which is then digested by restriction enzymes (BbsI, BamHI, DraI) to generate multiple shorter restriction fragments for electrophoretic analysis in an SSCP gel. The method is thus termed multiple restriction fragment (MRF)-SSCP. Two cases of chorionic samples and the blood samples of their parents were studied. The previously described amplification-created restriction site (ACRS) method was used to confirm the SSCP results obtained. Two polymorphic sites of the beta-globin gene which would influence the MRF-SSCP patterns are described, including a previously undescribed polymorphic site located at codon 3 (CAT or CAC) of the beta-globin gene.

Base Sequence↗
PubMed1993

Temporary arterial occlusion during intracranial aneurysm surgery.

Temporary arterial occlusion during intracranial aneurysm surgery is a safe and effective modality. It is not only an emergency measure for controlling aneurysmal bleeding, but also a helpful means for accurate and meticulous dissection and clipping of an intracranial aneurysm with the advantage of minimizing the chance of its premature rupture or causing damage to the vital neurovascular structures. This technique is especially useful for treating large or giant aneurysms, carotid-ophthalmic arterial aneurysms, or thin-walled and complicated aneurysms tightly adherent to their surrounding tissues. A series of 52 patients with temporary clipping of the involved arteries during intracranial aneurysm surgery were reviewed retrospectively, which represented 37.1% of all aneurysms operated on in Huashan Hospital, Shanghai Medical University during the same period (from 1980 to 1990). Of them, one died (1.9%), 10(19.2%) had immediate or early neurological deficits which were mostly resolved later. A follow-up study with an average time of 3.8 years showed that 98% of patients had an excellent and good recovery without significant deficits. Comparing these results with those in 88 patients with aneurysms operated on over the same period in which temporary clips were not used, there is clearly no significant difference. The use of brain protectors, barbiturates, hypothermia and some monitoring systems can increase the safe coefficient to the brain and reduce the occurrence of ischemic complications during the application of temporary arterial occlusion. However, there is so far neither an absolute reliable medication or monitor, nor a well accepted safe time-limits to vascular occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Role of mast cells in the development of liver fibrosis during experimental hepatocarcinogenesis in rats].

The role of mast cells (MC) in the development of liver fibrosis during experimental hepatocarcinogenesis in rats has been studied light microscopically, histochemically and electron microscopically. An increase in the number of MC in the proliferated connective tissue was found. The histochemical examination showed that the increased MC almost exclusively were connective tissue mast cells (CTMC), whilst mucosa mast cells (MMC) were only rarely seen. The electron microscopical observation revealed a close topographical relationship between MC and fibroblasts sending out pseudopodia, which encircled granula released from MC and phagocytized them. The fibroblasts with phagocytized MC granules were markedly activated showing enhanced formation of collagenous fibrils. Finally, the role of MC in the development of liver fibrosis is discussed.

Animals↗
PubMed1992

Chemical modification of alpha-bungarotoxin with bifunctional reagent, 1,5-difluoro-2,4-dinitrobenzene.

alpha-Bungarotoxin (alpha-BuTX) was modified with a bifunctional reagent, 1,5-difluoro-2,4-dinitrobenzene (DFDNB) to prepare the cross-linked derivatives. The modified products, obtained from the reaction at pH 8.5 with a 2-fold molar excess of DFDNB, were purified successively on a Sephadex G-50 and a SP-Sephadex C-25 columns, and, fast protein liquid chromatography (FPLC) on a Mono S column. The preparation was proved to be a homogeneous and dimeric form which arose from the intermolecular cross-linkage of alpha-BuTX through a dinitrophenylene (DPE) group. The cross-linked alpha-BuTX derivative still retained approximately 50% residual lethality and 70% residual binding activity to nicotinic acetylcholine receptor (nAChR). The modified derivative also showed relatively high antigenic activity toward anti-alpha-BuTX antibody as measured by competitive radioimmunoassay (RIA).

Animals↗
PubMed1991

Comparison of two screening methods, modified Hb H preparation and the osmotic fragility test, for alpha-thalassemic traits on the basis of gene mapping.

We evaluated 61 patients with two screening tests for alpha-thalassemia traits on the basis of endonuclease gene mapping. Comparing these two methods--the osmotic fragility test of the red cell and modified hemoglobin H inclusion staining for the sensitivity--we found that the latter was much superior to the former with 100% sensitivity in detecting heterozygous alpha-1 thalassemia and it was also specific as a confirmatory test for thalassemia traits. Red cell indices are still the basic screening tool and can be used together with modified Hb H inclusion staining. The osmotic fragility test was not better than the red cell indices and was not confirmatory. Besides the MCV, RBC, and discrimination functions, we found that RBC distribution width-standard deviation (RDW-SD) was consistently low in heterozygous alpha-1 thalassemia but not in heterozygous alpha-2 thalassemia. None of the above tests was shown to be really helpful in screening in the latter situation. We conclude that the modified Hb H inclusion staining is superior to the osmotic fragility test in screening of alpha-1 thalassemia.

Chromosome Deletion↗
PubMed1991

Using ultrasonic measurement of cardiac size in predicting congenital heart defect.

A Duplex Color apparatus equipped with real-time imaging and Doppler sector scanner was used to scan fetal hearts, ranging from 17 to 41 weeks gestational age. A total of 323 normal fetuses were studied. The four-chamber view was obtained in a horizontal section just above the level of the fetal diaphragm. Five variables of the Chinese fetal heart in relation to the width of the right ventricle, width of the left ventricle, ratio of right ventricle/left ventricle (RV/LV), length of the fetal heart and the cardiac volume of a four-chamber view were set against gestational age in weeks and expressed in regression equations. The ratio of RV/LV is quite constant in relation to the gestational age. The mean ranges between 0.9916 for 17 weeks gestation and 1.0045 for a term fetus. In 10 abnormal cases with congenital cardiac defects, using the 5th and the 95th percentiles of this normal data as cutoff points, the RV/LV ratio had the highest sensitivity rate of 70% (7/10) in predicting fetal cardiac anomaly. The width of the left ventricle was the second most sensitive parameter with a sensitivity of 4/10 (40%). The RV/LV ratio of a four-chamber view is a simple, time-saving screening parameter for predicting congenital cardiac defects antenatally.

Female↗