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Biomedical subjects

H H Cheng

Publications and source records attributed to H H Cheng.

At least 73 records · Page 4Linked to original sources
PubMed1998

Amphotericin B does not increase peritoneal fluid removal.

Intraperitoneal use of amphotericin B (AmB) has been reported to increase ultrafiltration during short peritoneal dwell in rabbits. In this study, we investigated the effect of AmB on peritoneal fluid kinetics in rats. A 4 hour dwell using 25 mL of 2.27% glucose dialysis solution without AmB (control, n = 6), with 1 mg/kg (L-AmB, n = 6) or with 10 mg/kg AmB (H-AmB, n = 6), and with frequent dialysate and blood sampling was done in Sprague-Dawley rats. 131I-albumin was added to the solution as an intraperitoneal (i.p.) volume marker. There was no difference in the drainage volumes measured at 4 hours of the dwell (26.2 +/- 1.1 mL, 26.0 +/- 1.5 mL, and 26.0 +/- 1.1 mL for the control, L-AmB, and H-AmB groups, respectively.) However, the i.p. volumes were higher at 60 minutes, 90 minutes, and 120 minutes of the dwell in the H-AmB group as compared to the other two groups (1 to 1.5 mL higher, all P < 0.05). There were no differences in the peritoneal fluid absorption rate (KE) and the lymphatic flow rate (KEB) between the three groups. The D/D0 for glucose and dialysis-over-plasma concentration ratio (D/P) values for urea, sodium, and total protein, as well as the diffusive mass transport coefficient (KBD) values for these solutes did not differ among the three groups. However, the D/P as well as the KBD values for potassium were significantly higher in the H-AmB and L-AmB groups as compared to the control group, resulting in significantly higher potassium clearances among the two AmB groups as compared to the control group. Our results suggest that i.p. use of AmB did not increase peritoneal fluid removal after 4 hours of dwell in rats. Although the basic membrane permeability may not be altered by AmB, the higher D/P and KBD values as well as the higher clearances for potassium in the AmB groups may suggest a local release of potassium due to the cytotoxic effect of AmB. The contribution of water release from local cells to the increase in i.p. volume in the H-AmB group cannot be ruled out.

Absorption↗
PubMed1997

Molecular analysis of major histocompatibility complex allelic associations with systemic lupus erythematosus in Taiwan.

OBJECTIVE: To investigate the association of HLA class II alleles/haplotypes, type I C2 deficiency gene, and tumor necrosis factor a gene promoter allele (TNF2) with systemic lupus erythematosus (SLE) in the Chinese population in Taiwan. METHODS: The HLA-DRB1 and DQB1 alleles were studied in 105 SLE patients and 115 controls by the polymerase chain reaction (PCR)/sequence-specific oligonucleotide probe method, the subtyping of DRB1*15/16 and DRB5 by PCR with sequence-specific primers, type I C2 deficiency gene by PCR, and TNF2 by PCR-Nco I restriction fragment length polymorphism. RESULTS: The frequencies of the HLA class II alleles DRB1*02, DRB1*1502, DRB5*0102, DQB1*0501, and DQB1*0602 and DR2-associated haplotypes DRB1* 1501,DRB5*0101,DQB1*0602 and DRB1*1502,DRB5* 0102,DQB1*0501 were higher among SLE patients than among controls; however, only DQB1*0501 was statistically significantly associated with SLE. No specific allele/haplotype was significantly associated with lupus nephritis. No subject had type I C2 deficiency. SLE patients had a marginally higher percentage of TNF2, which was in linkage disequilibrium with DR3. Since DR3 was not associated with SLE in this Taiwanese Chinese population, TNF2 might play a role in the immunopathogenesis of SLE. CONCLUSION: Although no HLA-DRB1 allele was found to be significantly associated with SLE, the associations with DQB1*0501 and TNF2 suggest that DQB1 and tumor necrosis factor a may be important genetic factors in SLE susceptibility in the Chinese population in Taiwan.

Adult↗
PubMed1997

Bruceine B, a potent inhibitor of leukocyte-endothelial cell adhesion.

Leukocyte adhesion to vascular endothelial cells is an essential step in the development of inflammatory diseases. We have searched for inhibitors of leukocyte-endothelial cell adhesion that could be used as anti-inflammatory drugs and found that bruceine B (0.2 microgram/ml; 0.44 microM) inhibited human neutrophil or T cell adhesion to tumor necrosis factor-alpha (TNF) stimulated human umbilical vein endothelial cells (HUVEC). The inhibition of neutrophil adhesion to TNF-stimulated HUVEC by bruceine B was not derived from cytotoxic effects, as determined by measurement of the level of lactate dehydrogenase (LDH) activity in conditioned medium. The effect of bruceine B on neutrophil adhesion to HUVEC was not seen when the neutrophils were preincubated with bruceine B. However, inhibitory effects were evident when the HUVEC were preincubated with bruceine B. Bruceine B also inhibited neutrophil adhesion to lipopolysaccharide-stimulated HUVEC and T cell adhesion to TNF-stimulated HUVEC. These findings suggest that bruceine B may have anti-inflammatory activity.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Lipid metabolism is altered by nebacitin in rats fed cooked-stored polished rice as the only dietary carbohydrate with or without exogenous cholesterol.

Male adult Wistar rats were randomly divided into four groups in a 2 x 2 factorial design and were fed diets containing cooked-stored polished rice (CSPR), with and without 0.7 g/100 g of Nebacitin [bacitracinneomycin sulfate (2:1, wt/wt)] and with and without 1 g cholesterol/100 g diet. The CSPR diet contained 1.87 g resistant starch/100 g. After 4 wk, arterial blood and liver were collected. Feces were collected during the last 7 d. Rats fed the diet with Nebacitin and cholesterol had higher serum total cholesterol than the rats fed diets without cholesterol. Serum triglyceride concentration was greater in rats fed Nebacitin, regardless of dietary cholesterol concentration. Rats fed the diet with Nebacitin and cholesterol had higher serum LDL cholesterol concentration and liver total cholesterol concentration than rats fed the other three diets. Rats fed the CSPR diet with Nebacitin both with and without cholesterol had a higher fecal resistant starch concentration and excretion and lower serum short-chain fatty acid concentration than rats fed the diets without Nabacitin. Hepatic cholesterol concentration was greater in rats fed Nebacitin only when the diet also contained cholesterol. Therefore, dietary Nebacitin alters lipid metabolism in rats, and some effects are most pronounced in those also fed cholesterol.

Animals↗
PubMed1997

Comparative mapping of the chicken genome using the East Lansing reference population.

The annotation of known genes on linkage maps provides an informative framework for synteny mapping. In comparative gene mapping, conserved synteny is broadly defined as groups of two or more linked markers that are also linked in two or more species. Although many anonymous markers have been placed on the chicken genome map, locating known genes will augment the number of conserved syntenic groups and consolidate linkage groups. In this report, 21 additional genes have been assigned to linkage groups or chromosomes; five syntenic groups were identified. Ultimately, conserved syntenic groups may help to pinpoint important quantitative trait loci.

Animals↗
PubMed1997

Mapping the chicken genome.

Most economically important traits are genetically complex and controlled by numerous genes. A quality genetic map is a prerequisite for identifying quantitative trait loci (QTL) that contain the genes involved in these traits. Currently, there are two internationally recognized reference families that are used to build genetic maps. In this paper, the East Lansing (EL) genetic map is described in detail. Presently, the EL genetic map contains 617 genetic markers, of which 589 are resolved into 41 linkage groups. The map coverage within linkage groups is over 2,700 cM, which is about the estimated size of the chicken genome. There are 322 microsatellite markers, which greatly enhances the utility of this genetic map for genome-wide QTL searches. Also, 101 genes have been mapped, which will aid in the development of a comparative map. Further efforts to improve the genetic map and the potential for the map to identify QTL are discussed.

Animals↗
PubMed1997

DNA marker technology: a revolution in animal genetics.

The development of DNA-based markers has had a revolutionary impact on gene mapping and, more generally, on all of animal and plant genetics. With DNA-based markers, it is theoretically possible to exploit the entire diversity in DNA sequence that exists in any cross. For this reason, high resolution genetic maps are being developed at an unprecedented speed. The most commonly used DNA-based markers include those based on a cloned and (usually) sequenced DNA fragment and other, more random, assays for genetic polymorphism that can be grouped under the heading of fingerprint markers. The advantages and disadvantages of the various marker types are discussed, along with their application to the reference chicken genetic linkage maps and to the search for quantitative trait loci (QTL). The prospects for the use of DNA-based markers in marker-assisted selection are considered, along with likely future trends in poultry gene mapping. Further development of both physical and linkage genome maps of the chicken will allow animal scientists to more efficiently detect and characterize QTL and will provide them access to the wealth of genetic information that is being generated about the human genome and the genomes of model species, such as the mouse and Drosophila.

Animals↗
PubMed1997

Characterization of CR1 repeat random PCR markers for mapping the chicken genome.

Polymerase chain reaction (PCR) primers complementary to portions of the chicken repetitive element CR1 have been used previously to generate useful markers on the chicken genome linkage map. To understand better the genetic basis for this technique and to convert CR1-PCR loci to markers useful in physical genome mapping, five polymorphic CR1-PCR-generated DNAs were cloned and partially sequenced. Inverse PCR was then employed to clone the corresponding region of the genomes of both the Jungle Fowl (JF) and White Leghorn (WL) parental DNA templates. Our results demonstrate that some of the CR1-PCR-generated DNAs arise from priming at an endogenous CR1 element, whereas others are due to chance complementarity between the CR1-PCR primer in use and random annealing sites in the genome, unrelated to a demonstrable CR1 element. In all five instances, it was possible to identify the sequence difference between the JF and WL parental DNAs that gave rise to the initial polymorphism and design allele-specific PCR primer sets that uniquely detect that polymorphism. In four of the five instances, the polymorphism was a one or two basepair sequence difference within the primer annealing site, but in the fifth case the responsible difference was outside, but very close to, the annealing site. In all instances the allele-specific PCR for the sequence polymorphism mapped identically with the corresponding CR1-PCR amplification polymorphism. We conclude that CR1-PCR provides an efficient and reliable mechanism for genome mapping in avians that can correlate linkage and physical mapping approaches.

Animals↗
PubMed1997

Non-association between Rfp-Y major histocompatibility complex-like genes and susceptibility to Marek's disease virus-induced tumours in 6(3) x 7(2) F2 intercross chickens.

Marek's disease (MD) is a lymphoproliferative disease caused by a member of the herpesvirus family, and the best understood genetic resistance to MD involves the chicken major histocompatibility complex (MHC) B-complex. Preliminary observations have suggested that MHC-like Rfp-Y genes might also influence the incidence of MD. This study describes the differentiation and definition of unique Rfp-Y genes in inbred lines 6(3) and 7(2), lines that possess identical B-complex genes, but that are resistant or susceptible to MD, respectively. To assess if Rfp-Y genes affect susceptibility to MD, 265 6(3) x 7(2) F2 chickens were challenged with the JM strain of MD virus at 1 week of age and were evaluated for MD lesions at up to 10 weeks of age. Genotyping of the F2 chickens for Rfp-Y haplotypes was performed by restriction fragment length polymorphism analysis of genomic DNA using TaqI and a B-FIV probe. Analysis of variance and interval mapping procedures were used to determine association between the Rfp-Y haplotypes and the phenotypic MD values of the F2 chickens. The cosegregation analysis of 265 F2 chickens indicated that there was no association between Rfp-Y haplotypes and MD susceptibility. Furthermore, the fact that the Rfp-Y haplotypes fit the 1:2:1 segregation ratio and the Rfp-Y allele frequencies did not differ significantly from 0.5 in the full population or in selected subpopulations (of either 40 MD-resistant or 39 MD-susceptible chickens) also indicated that Rfp-Y haplotypes do not significantly influence MD susceptibility. We conclude that Rfp-Y haplotypes do not play a major role in determining the genetic susceptibility to MD in 6(3) x 7(2) F2 White Leghorn chickens.

Animals↗
PubMed1996

Degradation of 3-hydroxy-3-methylglutaryl-CoA reductase in endoplasmic reticulum membranes is accelerated as a result of increased susceptibility to proteolysis.

The endoplasmic reticulum (ER) membrane protein 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is subject to regulated degradation when cells are presented with an excess of sterols or mevalonate. In this report, we demonstrate the degradation of HMG-CoA reductase in ER membranes prepared from cells which have been pretreated with mevalonate or sterols prior to membrane purification. Degradation of HMG-CoA reductase in membranes prepared from pretreated cells is more rapid than in membranes prepared from cells which have received no regulatory molecules. In vitro degradation is blocked by protease inhibitors previously shown to inhibit reductase degradation in vivo and is specific for intact HMG-CoA reductase. The lumenal contents of the ER membranes are dispensible for the regulated proteolysis and the proteases responsible for reductase degradation are stably associated with the ER membrane. Regulated proteolysis of HMG-CoA reductase is inhibited by lactacystin, a newly defined inhibitor of the multicatalytic protease, the proteasome, and in vitro degradation of reductase correlates with the presence of proteasome subunits in purified ER membranes. The ubiquitin system for protein degradation, which has recently been shown to be required for the degradation of several ER membrane proteins, is not required for the degradation of HMG-CoA reductase. Finally, we conclude that the regulated proteolysis of HMG-CoA reductase in response to regulatory molecules such as mevalonate or sterols is mediated by increased susceptibility of the reductase to ER proteases, rather than the induction of a new proteolytic activity.

Acetylcysteine↗
PubMed1996

Comparison of the efficacy of tropisetron versus a metoclopramide cocktail based on the intensity of cisplatin-induced emesis.

Cisplatin-induced emesis is one of the most feared side effects in cancer treatment. High-dose metoclopramide may prevent only 30-40% of cases of acute emesis. Investigations to test the efficacy of new antiemetics are mandatory. We compared the efficacy, toxicity, and patients' preference for tropisetron, a new 5-hydroxytryptamine3 (HT3) receptor antagonist, with those of a combination of high-dose metoclopramide, dexamethasone, diphenhydramine, and lorazepam (metoclopramide cocktail) in a randomized crossover study for the control of nausea and vomiting during cisplatin-containing chemotherapy. A total of 62 chemotherapy-naive women were included and followed over 3 consecutive courses. Detailed analysis comparing the incidence of acute emesis for each 4 h period following cisplatin infusion was also performed. Complete protection from acute emesis was obtained in 48% of patients receiving tropisetron and 29% of patients receiving the metoclopramide cocktail over the first two courses of chemotherapy (P = 0.029). When the frequency of acute emesis in all patients was compared on a daily basis, no significant difference was found. When emesis frequency was compared over each 4 h period following infusion of cisplatin, tropisetron was superior to the metoclopramide cocktail during the first, the second, and the first and second periods (P = 0.0001, P = 0.01 and P = 0.0006, respectively). This superiority reversed after 12 h but did not reach statistical significance (P = 0.112). Tropisetron was more effective in controlling acute nausea, but metoclopramide provided better control of delayed emesis. A drop in efficacy over successive courses was observed in patients receiving metoclopramide first but was not seen in tropisetron-first patients. A tendency for tropisetron preference was observed. Tropisetron is more effective than the metoclopramide cocktail in the control of chemotherapy-induced vomiting within 8 h of the implementation of cisplatin and in the control of nausea on the 1st day. To improve the control of chemotherapy-induced emesis, further investigations on the additional tropisetron dosing at 8 h after cisplatin infusion or the combination use of tropisetron and other antiemetics by a continuous 4 h period of observation and comparison are mandatory.

Adult↗
PubMed1996

Mapping functional chicken genes: an alternative approach.

Functional genes were selected for linkage analysis mapping using the East Lansing (EL) reference population ¿[Jungle Fowl (JF) x White Leghorn (WL)] x WL¿. The approach used was based on the identification of DNA sequence polymorphisms in the introns of those genes found in JF and WL. Deoxyribonucleic acid sequence analysis revealed single base substitutions in introns of six Type I marker genes: adenylate kinase 1 (AK1), aldolase B (ALDOB), a lysosomal membrane protein gene (LAMP1), vitellogenin 2 (VTG2), apolipoprotein A1 (APOA1), and creatine kinase B (CKB). Transitions or transversions were found in introns of AK1, ALDOB, LAMP1, VTG2, APOA1, and CKB. A transversion in the intron of the JF allele of AK1 generated a unique BspHI cleavage site. The design of polymerase chain reaction (PCR) primers based on the site of base substitution led to the specific amplification of the JF allele in the remaining five genes. A size polymorphism in the PCR production derived from iron response element binding protein (IREBP) distinguished the JF from the WL allele. Linkage analysis of the EL reference population revealed that these candidate genes were located in the following EL linkage groups (E) or chromosomes (Chrom) of the chicken genome: AK1 (E41), VTG2 (E43), APOA1 (E49), CKB (E07), LAMP1 (E01), ALDOB (Chrom Z), and IREBP (Chrom Z). Provided that a base substitution can be found in the parents of the reference population, this PCR-based approach can be used to map any cloned candidate gene. This approach will lead to further information on synteny of the chicken genome with cognate genes of mammalian species.

Adenylate Kinase↗
PubMed1996

Systemic lupus erythematosus with intussusception: a case report.

A 19-year-old male with systemic lupus erythematosus, had initially presented three years previous by malar rash and nephritis. In the past 2 weeks, he experienced bloody diarrhea and lower abdominal pain. Intussusceptions of the distal to the terminal ileum, terminal ileum to cecum and cecum to ascending colon were proved via exploratory laparotomy. Mesenteric lymphadenopathy was thought to be the leading cause. This is the second case of systemic lupus erythematosus with intussusception described in the literature.

Adult↗
PubMed1995

Distortion in TGF beta 1 peptide immunolocalization in biliary atresia: comparison with the normal pattern in the developing human intrahepatic bile duct system.

Biliary atresia is an important cause of neonatal obstructive jaundice in which there is inflammation, sclerosis and eventual obliteration of the bile duct system. Its onset may be antenatal, affecting the normal development of the biliary system. The intrahepatic biliary system is derived from the ductal plate, a sheath of cuboidal epithelium that appears at the hepatocyte-mesenchymal junction around the portal vein branches at 6 weeks gestation. This epithelial structure is moulded into a network of tubular bile ducts by the proliferating mesenchyme. Certain portions of the ductal plate are selected to become definitive bile ducts, while redundant biliary epithelium is deleted. The molecular dynamics controlling the intra-uterine development of the biliary system in humans are not yet clearly understood. Transforming growth factor-beta 1 is a cytokine that stimulates mesenchymal proliferation and inhibits epithelial growth, and has been shown to be important in organogenesis. In the present study, the pattern of TGF beta 1 peptide immunolocalization was investigated with the aid of computerized image analysis, in normal human bile duct development and in biliary atresia. TGF beta 1 peptide was detected within hepatocytes and ductal plate epithelium from 7 weeks gestation; increased TGF beta 1 immunoreactivity was present within the epithelium of developing bile ducts at 13 weeks gestation, and apical polarization of the cytokine was observed from 16 weeks gestation. In biliary atresia, the TGF beta 1 immunoreactivity pattern within the bile duct structures at the porta hepatis and within intrahepatic portal tracts resembled that of the primitive ductal plate, and there was no significant apical polarization. This may indicate a developmental arrest in the normal ductal plate remodelling process in biliary atresia, and suggests an underlying epithelial-mesenchymal interactive disorder.

Adolescent↗
PubMed1995

Development of a genetic map of the chicken with markers of high utility.

Microsatellites are tandem duplications with a simple motif of one to six bases as the repeat unit. Microsatellites provide an excellent opportunity for developing genetic markers of high utility because the number of repeats is highly polymorphic, and the assay to score microsatellite polymorphisms is quick and reliable because the procedure is based on the polymerase chain reaction (PCR). We have identified 404 microsatellite-containing clones of which 219 were suitable as microsatellite markers. Primers for 151 of these microsatellites were developed and used to detect polymorphisms in DNA samples extracted from the parents of two reference populations and three resource populations. Sixty, 39, 46, 49, and 61% of the microsatellites exhibited length polymorphisms in the East Lansing reference population, the Compton reference population, resource population No. 1 (developed to identify resistance genes to Marek's disease), resource population No. 2 (developed to identify genes involved in abdominal fat), and resource population No. 3 (developed to identify genes involved in production traits), respectively. The 91 microsatellites that were polymorphic in the East Lansing reference population were genotyped and 86 genetic markers were eventually mapped. In addition, 11 new random amplified polymorphic DNA (RAPD) markers and 24 new markers based on the chicken CR1 element were mapped. The addition of these markers increases the total number of markers on the East Lansing genetic map to 273, of which 243 markers are resolved into 32 linkage groups. The map coverage within linkage groups is 1,402 cM with an average spacing of 6.7 cM between loci. The utility of the genetic map is greatly enhanced by adding 86 microsatellite markers. Based on our current map, approximately 2,550 cM of the chicken genome is within 20 cM of at least one microsatellite marker.

Animals↗
PubMed1994

Experimental study of the osteogenic capacity of periosteal allografts: a preliminary report.

A total of 16 rabbits were used in this investigation. Beijing long-eared white rabbits served as donors and immunologically incompatible Chinchilla rabbits as recipients. Periosteal flaps were stripped from the femurs of 8 donor rabbits and implanted into the muscles of both thighs of 8 recipients. Revascularization of the grafts was done only on the left side. Immunosuppressants were administered orally beginning the day of surgery. The animals were observed for 1-4 months. A series of radiography, histomorphology, fluorochrome labelling, and electron microscopic examinations were performed. The results demonstrated that all of the revascularized periosteal allografts had new bone formation (8/8), while the nonrevascularized periosteal allografts had none (0/8). The difference in the rate of new bone formation between the two groups was statistically significant.

Anastomosis, Surgical↗
PubMed1994

Use of revascularized periosteal allografts for repairing bony defects: an experimental study.

This is an experimental study on the potential of revascularized periosteal allografts for repair of bony defects. Beijing long-eared white rabbits were used as donors and immunologically incompatible Chinchilla rabbits were used as recipients. The periosteum was stripped off from the femurs of the 6 donor rabbits and transplanted to bony defects of 1.2 cm over the radius of the 12 recipients using microsurgical anastomoses of the blood vessels. In the control group of 8 rabbits the same radial bony defects were produced without the transplantation of periosteal grafts. Immunosuppressants were administered after surgery. The animals were observed for 4 months using a series of radiography, histomorphology, fluorochrome labelling and electron microscopy. Results revealed no bony healing of the defects in the control group, but 9 of the 12 defects healed in the experimental group. The results indicated revascularized periosteal allografts were able to form new bone and heal the 1.2 cm radial bone defect in rabbits.

Anastomosis, Surgical↗