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Biomedical subjects

K H Chen

Publications and source records attributed to K H Chen.

At least 55 records · Page 3Linked to original sources
PubMed1997

Rapid identification of mycobacteria to the species level by polymerase chain reaction and restriction enzyme analysis--a case report of corneal ulcer.

We report a case of corneal ulcer caused by nontuberculous mycobacteria which was confirmed by smear and culture. We attempted a new method for the rapid identification of mycobacteria to the species level on the basis of evaluation by the polymerase chain reaction of the gene encoding. The method is involved with restriction enzyme analysis of PCR product obtained with primers common to all mycobacteria. Using the restriction enzyme Bst EII and Hae III, clinically relevant and other frequent laboratory isolates were differentiated to the species or subspecies level by PCR-restriction enzyme analysis. The main prevalence of pattern analysis is Mycobacterium chelonae subsp. abscessus in this case. The outcome suggests that PCR-restriction enzyme analysis should be a useful method for early diagnosis concerning nontuberculous mycobacterial keratitis.

Corneal Ulcer↗
PubMed1996

Pelvic inflammatory pseudotumor with central infectious abscess: a case report.

Inflammatory pseudotumors (IPT) are a fascinating group of lesions which involve almost all organs and tissues of the body. The clinical manifestations are diverse. Final diagnosis can only be made by meticulous microscopic examination of different areas of the tumor. A 60 year-old woman had a pelvic IPT with central infectious abscess. The lesion involved her urinary bladder, mesentery, terminal ileum, right rudimentary ovary and the abdominal wall. It mimicked malignant tumor clinically, and led to total surgical excision. Early follow-up has shown a favorable results. IPTs are extremely uncommon. The characteristic pathologic picture is a reparative fibroblastic tissue infiltrated by polymorphic inflammatory cells. Pelvic IPT, admixed with central infectious abscess, is even rarer. Prior pelvic surgery and pasteurella hemolytica infection might be causative factors in this reported case.

Abdominal Abscess↗
PubMed1995

The bovine DNA polymerase beta promoter: cloning, characterization and comparison with the human core promoter.

The core promoter of the human DNA polymerase beta (beta Pol)-encoding gene (POL beta) is regulated through cis-elements for the ATF/CREB protein(s), and GC box-binding and initiation-site-binding proteins. The mechanism of promoter regulation has been studied using a nuclear extract transcription system from HeLa cells [Narayan et al., J. Biol. Chem. 269 (1994) 12755-12763]. To study the homologous promoter (ppol beta) in a bovine system, we cloned and characterized the 5'-flanking region of the bovine gene (pol beta). A 15.3-kb fragment of bovine genomic DNA containing the first two exons and 11 kb of 5'-flanking region was isolated from a testis library in bacteriophage lambda EMBL3. S1 nuclease mapping and primer extension analysis of the 5'-end of the pol beta mRNA identified the major transcription start point (tsp), which is located 142-bp 5' of the translational start codon. In transient expression assays using a bovine cell line, analysis of various 5'-deletion mutants demonstrated that a fragment of only 91-bp 5' of the tsp had promoter activity similar to that of a 1.37-kb fragment, so that cis-elements for basal transcription are located within this approx. 100-bp core promoter, as in the human promoter (pPOL beta). Comparison of the core promoters from the bovine and human genes revealed striking similarity, including an almost precise match of the tsp, the ATF/CREB-binding and Sp1-binding sites, and the spacing separating them.

Animals↗
PubMed1995

Molecular basis of glucose-6-phosphate dehydrogenase (G6PD) deficiency in three Taiwan aboriginal tribes.

We have investigated glucose-6-phosphate dehydrogenase (G6PD) deficiency in 220 unrelated aboriginal male subjects who belong to three different tribes (Saisiat, Ami, and Yami) in Taiwan. Our results show that the G6PD deficiency rates for Saisiat, Ami, and Yami people are 9.0% (6/67), 6.1% (6/99), and 0% (0/54), respectively. Among these deficiency cases, 4 of 6 (66.7%) Saisiat subjects have the 493 A-->G mutation and one carries the 1376 G-->T mutation, whereas, in Ami subjects, we found that four of six (66.7%) affected males have the 592 C-->T mutation and one carries the 493 A-->G mutation. These results contrast with our previous findings for Taiwan Chinese, in whom the 1376 G-->T mutation is the major mutant allele and accounts for 52.3% of the deficiency cases. This is the first report of G6PD deficiency characterized at the DNA level in Taiwan aboriginal populations.

Base Sequence↗
PubMed1995

A novel method for cloning DNA of plant-pathogenic mycoplasmalike organisms.

A novel method was developed for cloning the DNA from a representative of plant-pathogenic mycoplasmalike organisms (MLOs). This procedure utilized random amplified polymorphic DNA (RAPD) and basic recombinant DNA techniques. It consisted of amplification of total DNA from diseased plants using one oligonucleotide primer with arbitrary sequence and separation of RAPD products in agarose gels. Unique RAPD band(s) of MLO origin was (were) then recovered from the gel and cloned into the specifically designed vector pCR II. With this method, a DNA fragment of the SA2 isolate of grapevine yellows MLO was cloned. Southern blot hybridizations revealed that most of the DNA in the unique RAPD band was derived from MLO. Results from dot-blot hybridizations used for screening showed that approximately 60% of transformants harbored MLO-specific recombinant plasmids. Our approach is relatively simple, quite efficient, and not limited by the amount of diseased material available. It does not depend on DNA sequence information for primer design and does not rely on restriction endonucleases for cloning. In addition, it can be used directly for disease diagnosis and for differentiation of closely related MLOs. Our system may serve as a model for cloning DNAs of other fastidious plant pathogens.

Base Sequence↗
PubMed1995

Effect of substituting steam-flaked sorghum for concentrate on lactation and digestion in dairy cows.

Thirty-five lactating cows (110 DIM), allotted to five dietary treatments for 70 d, were fed 0, 15, 30, or 45% of dietary DM as steam-flaked sorghum grain (360 g/L) in place of equal amounts of a mixture (DM basis) of 40% steam-rolled corn, 13% rolled barley, 20% wheat mill run, and 27% ground beet pulp in four diets. Thinly flaked sorghum grain (283 g/L) was also fed at 15% of dietary DM. The DMI tended to increase as flaked sorghum increased. Yields of milk and milk protein and percentages of milk protein and SNF increased linearly as sorghum increased. Milk yield of cows fed 15% of DM as the thinly flaked sorghum was higher than for cows fed the 360 g/L flake at 15% and similar to that of cows fed the 360 g/L flake at 30 or 45%. Feed efficiencies and changes in BW and body condition score were unaffected by treatment. As steam-flaked sorghum increased, digestibilities of DM, OM, ADF, NDF, and CP tended to decrease, except for the thinly flaked sorghum fed at 15% of DM. Apparent starch digestibility in the total tract was unaltered by diet. The 30 to 45% of DM fed as steam-flaked sorghum grain (360 g/L) increased yields of milk and milk protein, and thinly flaked sorghum (283 g/L) fed at 15% of DM increased milk yields over that of the control diet or that with the 360 g/L flake at 15% of DM.

Animal Feed↗
PubMed1995

Influence of steam-flaked sorghum grain and supplemental fat on performance of dairy cows in early lactation.

Effects of sorghum grain processing and fat supplementation on milk yield and composition and nutrient digestibilities were studied. Thirty-six Holstein cows were assigned at 5 d of lactation for 91 d to treatment: 1) dry-rolled sorghum, no added fat; 2) dry-rolled sorghum plus Ca salts of long-chain fatty acids; 3) steam-flaked sorghum, no added fat; and 4) steam-flaked sorghum plus Ca salts of long-chain fatty acids. Fat increased ether extract in diets from 5.7 to 7.5% of DM. Milk yield was 4.0 kg/d (12%) higher for cows fed steam-flaked than dry-rolled sorghum. Fat tended to decrease milk yield because of lower DMI, and feed efficiencies increased 15%. Milk protein decreased .14% on dry-rolled sorghum with added fat, but only .01% on the steam-flaked diet. Milk protein yield was higher for cows fed flaked than rolled sorghum. Flaking decreased milk fat percentage, but not yield. Added fat decreased shorter chain fatty acids in milk (C4 to C14), but oleic acid increased. Flaking increased C10, C12, and C14, but decreased oleic acid. Digestibilities for DM, CP, starch, and ether extract were higher for flaked and fat-supplemented diets. Flanking of sorghum prevented the milk protein decrease reported for early lactation cows fed added fat.

Animal Feed↗
PubMed1995

Effect of enzyme treatment or steam-flaking of sorghum grain on lactation and digestion in dairy cows.

Effects of addition of a fungal enzyme (reported to have amylolytic and proteolytic activities) to dry-rolled or steam-flaked sorghum grain (40% of dietary DM) were tested for 70 d with 36 lactating Holstein cows in a 2 x 2 factorial arrangement of treatments. Compared with dry-rolling, steam-flaking resulted in increased yield of milk, milk protein, and 3.5% FCM; percentage of milk protein; and efficiency of feed utilization (FCM/DMI). Milk casein (as a percentage of milk N) was not altered, but milk urea N was lower, for cows fed steam-flaked sorghum. With steam-flaking, milk fat percentage decreased, short-chain fatty acids (C8 to C14) increased, but long-chain fatty acids (C16 to C18) were not affected. No yield parameters were altered by enzyme addition, except that the percentage of lactose in milk increased (5.02 vs. 4.96%). Steam-flaking of sorghum grain increased digestibilities of DM, OM, and starch (63 vs. 57%; 66 vs. 59%; and 98 vs 83%, respectively) compared with dry rolling. Enzyme addition did not affect starch digestibility, but digestibilities of DM, OM, CP, and NDF were greater than flaked grain was treated with enzyme, resulting in significant interaction effects. This study demonstrated higher milk and milk protein yields for cows fed steam-flaked sorghum than for cows fed dry-rolled sorghum, but addition of a sorghum-specific enzyme had no significant effect.

Animal Feed↗
PubMed1995

HLA DQA1 genotypes and its interaction with HLA DQB1 in Chinese IDDM living in Taiwan.

To study the role of the HLA DQA1 gene and its interaction with DQB1 in the susceptibility of IDDM, subjects with insulin-dependent (type 1) diabetes mellitus and non-diabetic unrelated controls were recruited from a Chinese population living in northern Taiwan. HLA DQA1 exon 2 was enzymatically amplified by polymerase chain reaction. HLA DQA1 alleles were diagnosed by dot blotting and hybridization with 11 sequence-specific oligonucleotide probes. Among all the DQA1 alleles, DQA1*0301 and DQA1*0501 were more frequent while DQA1*0102, DQA1*0103 and DQA1*0601 were less frequent in Chinese with IDDM than in controls. Among the DQA1 genotypes, only DQA1*0301/0301 and DQA1*0301/0501 were associated with increased risk to IDDM while DQA1*0301/0601 and DQA1*0102/0103 were protective against IDDM in our population. As the cell surface HLA DQ molecules were formed from each DQA1 and DQB1 alleles either in cis- or trans-position, the numbers of susceptible HLA DQ alpha beta heterodimers were then derived from the genotypes of HLA DQA1/DQB1 in each person. The numbers of the possible diabetogenic DQ alpha beta dimers correlated with the degree of risk to IDDM (r = 0.92) but were not statistically significant (p > 0.05). Subjects with absence of diabetogenic HLA DQ molecules were resistant to developing IDDM while subjects with two or more forms of diabetogenic DQ molecules were associated with increased risk to IDDM. In conclusion, both DQA1 and DQB1 genes, which determine the formation of susceptible DQ alpha beta heterodimers, were significantly associated with IDDM in Chinese subjects living in Taiwan.

Alleles↗
PubMed1994

Identification and grouping of mycoplasmalike organisms associated with grapevine yellows and clover phyllody diseases based on immunological and molecular analyses.

Immunofluorescent staining, dot blot hybridization, PCR, random amplified polymorphic DNA (RAPD) markers, and restriction fragment length polymorphism wee used to study the genetic relatedness among mycoplasmalike organisms (MLOs) associated with several geographically diverse grapevine yellows diseases (CA1, CH1, SA1, and SA2 from Bologna, Italy; GYU from Udine, Italy; GYR from Rome, Italy; and GYG from Germany). The relationship between these and MLOs associated with clover phyllody diseases in Italy (CPhB and CPhC) and Canada (CPhCa) was also examined. Two monoclonal antibodies reacted with MLOs of GYU-, CPhB-, and CPhC-infected periwinkles. Dot blot hybridization with two cloned GYU DNA fragments, GYD-1 and GYD-2 inserts, showed that both hybridized with DNAs of GYU-, CPhB-, and CPhC-infected periwinkles but not with those of GYR and CPhCa. In addition, GYD-1 insert hybridized with DNAs of CA1, CH1, SA1, SA2, and GYG. Three primer pairs were developed in PCR experiments for this study. By using primer set GYD2P1F and GYD2P1R, a 600-bp DNA fragment was amplified only when DNAs from GYU-, CPhB-, and CPhC-infected plants were used as templates. With the primer pair GYD2P1F and GYD2P2R, a 550-bp DNA fragment was amplified from GYU, CPhB, CPhC, and GYG. The primer pair GYD1P1F and GYD1P2R, on the other hand, could amplify all isolates, although the patterns of PCR products were not identical for all isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

HLA-DQB1 codon 57 and IDDM in Chinese living in Taiwan.

OBJECTIVE: To study the human leukocyte antigen (HLA)-DQB1 genetic background in the Chinese population in Taiwan and its association with the low incidence of insulin-dependent diabetes mellitus (IDDM) in this population. RESEARCH DESIGN AND METHODS: Forty-eight IDDM patients and 59 nondiabetic unrelated control subjects were recruited from the population in Taiwan. HLA-DQB1 exon 2 was enzymatically amplified by polymerase chain reaction. HLA-DQB1 alleles were diagnosed by dot blotting and hybridization with 16 sequence-specific oligonucleotide probes. RESULTS: DQB1*0201 and DQB1*0302 alleles were more frequent and DQB1*0301 and DQB1*0601 were less frequent in Chinese with IDDM than in control subjects. Genotypes for homozygous non-aspartic acid residue (NA/NA) at position 57 were positively associated with IDDM at a relative risk of 4.34 (P < 0.001), and those for homozygous aspartic acid (A/A) were negatively associated with IDDM at a relative risk of 0.14 (P < 0.001). Among the NA/A heterozygotes, only DQB1*0201/DQB1*0303 was significantly increased in IDDM subjects. CONCLUSIONS: The amino acid residue at position 57 of HLA-DQ beta-chain is significantly associated with the development or prevention of IDDM in Chinese subjects living in Taiwan. Other genetic and environmental factors may also play important roles in pathogenesis of IDDM.

Adolescent↗
PubMed1994

Cerebrospinal fluid interleukin-6, prostaglandin E2 and autoantibodies in patients with neuropsychiatric systemic lupus erythematosus and central nervous system infections.

Cerebrospinal fluid (CSF) from patients with a variety of central nervous system (CNS) disorders was assayed for cytokines, prostaglandins, and autoantibodies. CSF interleukin-6 (IL-6) in patients with CNS infection (374.24 +/- 92.61 pg/mL) and neuropsychiatric systemic lupus erythematosus (NP-SLE) (71.40 +/- 5.89 pg/mL) were significantly higher than in patients with CNS inflammation (33.92 +/- 29.36 pg/mL) or controls (non-inflammatory CNS diseases) (4.35 +/- 3.00 pg/mL). Interleukin-1 beta, interferon alpha, and tumor necrosis factor alpha were undetectable in these samples: CSF prostaglandin E2 (PGE2) also exhibited similar patterns as IL-6. CSF immunoglobulin G (IgG) in patients with NP-SLE (8.84 +/- 1.80 mg/dL) was much higher than in patients with CNS infection (4.65 +/- 3.09 mg/dL), CNS inflammation (2.54 +/- 1.24 mg/dL), or controls (2.11 +/- 1.03 mg/dL). CSF autoantibodies against calf thymus antigens were present in patients with NP-SLE but not in patients with CNS infection as demonstrated by immunoblot. These results suggest that high IL-6 and PGE2 in CSF favors the diagnosis of CNS infection, while modestly elevated IL-6, high IgG, and autoantibodies against calf thymus antigens in CSF are the features of NP-SLE.

Autoantibodies↗
PubMed1994

Effect of steam flaking of corn and sorghum grains on performance of lactating cows.

The objective of this study was to compare the relative feeding value of sorghum versus corn grain in rolled or steam-flaked forms in diets for lactating dairy cows. Twenty-four Holstein cows (averaging 110 DIM) were divided into four groups and fed diets of 40% grain as dry-rolled sorghum, steam-rolled corn, steam-flaked sorghum, or steam-flaked corn for 70 d. Compared with rolling, flaking of both grains increased yields of milk, milk protein and fat, and protein percentage of milk, but differences tended to be greater for sorghum than for corn. Efficiency of feed utilization was higher for steam-flaked than for dry-rolled sorghum but was unaffected by corn processing. Flaking of both grains increased total tract digestibilities of DM, OM, CP, starch, ADF, and NDF. Estimates for NEL were 21% higher for flaked than for rolled sorghum and 6% higher for flaked than for rolled corn. No differences in performance of cows existed between corn and sorghum grains. Cows fed 40% of their diet as steam-flaked sorghum or corn yielded more milk and milk protein than those fed the rolled form of the grains, and no differences existed between types of grain fed.

Animal Feed↗
PubMed1994

Effect of source and amount of supplemental fat on lactation and digestion in cows.

Thirty Holstein cows averaging 50 DIM were assigned to five dietary treatments for 75 d to determine the effects of source and amount of supplemental fat on milk yield, milk composition, and nutrient digestibilities. Diets were 1) control, 2) diet 1 plus 12% whole cotton-seed, 3) diet 2 plus 2.2% safflower oil, 4) diet 2 plus 2.2% prilled tallow fatty acids, and 5) diet 2 plus 4.4% prilled tallow fatty acids. Milk yield was increased an average of 2.1 kg/d by addition of 2.2% prilled tallow fatty acids or safflower oil to the diet (7% fatty acids) containing 12% whole cottonseed. However, when fatty acids were increased to 9.1% with additional prilled tallow fatty acids, milk yield, DMI, and fatty acid digestibility decreased. Whole cottonseed alone and in combination with all fat additions decreased milk protein concentrations. Safflower oil increased C18:0, C18:1, and C18:2 fatty acids in milk. Digestibilities of OM, NDF, and ADF were not affected by diet. Supplementation of a saturated or unsaturated fat source to increase fatty acid content to 7.0% of dietary DM increased milk yield, but a further increase in fat to 9.1% with the saturated source appeared excessive for cows yielding 30 to 35 kg/d of milk.

Animals↗
PubMed1994

Heat stress interactions with protein, supplemental fat, and fungal cultures.

Cows that were subjected to hot environmental temperatures yielded less milk (3.1 kg/d) on a diet high in CP (18.4%) and of medium degradability (65%) than on diets high in CP of low degradability (59%) or medium in CP (16.1%). The high CP diets were associated with decreased DMI and higher water intake, ruminal NH4, and blood urea. Negative effects on yield from the high CP, medium degradability diet were not observed at moderate temperatures. Evaporative cooling of cows in hot weather resulted in a greater milk yield response to low versus medium rumen-undegradabale protein diets than for uncooled cows. Evaporative cooling of cows also affected response to protein quality. For cooled cows, high Lys diet (soybean, fish, and blood meals) increased milk yield 14% over that with low Lys diet (corn gluten meal), but, for uncooled cows, a high Lys diet only increased yield by 9%. Percentage of CP, degradability, and protein quality had no effect on body temperatures or respiration rates of lactating cows. Some, but not other, reports showed that supplementation of 2 to 2.5% fat to diets fed under hot summer conditions resulted in less yield response than when fat was added at moderate temperatures. In several studies, fungal cultures (3 to 5 g/d) in the diet decreased body temperatures and respiration rates in hot, but not cool, weather. Increased milk yields and cellulose digestibility also resulted from dietary fungal cultures in some, but not all, trials. The mechanism of action exerted by fungal cultures on body temperature and respiration rate is unclear.

Animal Feed↗
PubMed1994

Clustering scheme for heterogeneity grouping of healthy adolescents based on a profile of serum biochemical variables.

All 890 study subjects attended two serum biochemistry screenings at an interval 3.5 years, the first while they were aged between 14 to 17 years (mean 15.5 and standard deviation 0.7). Three mutually independent laboratory indices--hepatocellular damage, liver metabolism, and outer-liver measurement--were identified as physiological scales by principal component analysis on ten common serum biochemical tests. Existence of a subgroup for an entity of healthy adolescents were supported by sum-of-squares clustering analysis of these three-dimensional indices. The consistency between two time-point repeated screenings for each of the same subjects confirmed the practicability of clustering schemes. The resulting cluster pattern for each screening bore a relation to gender or hepatitis B surface antigen (HBsAg) classifications. These features are expected to provide insight into normal references with enhanced group homogeneity, and lead to an improved multivariate protocol that will aid in health monitoring of subgroups with high risk.

Adolescent↗
PubMed1993

Identification of a nuclear protein binding element within the rat brain protein kinase C gamma promoter that is related to the developmental control of this gene.

Protein kinase C gamma (PKC gamma) is a brain-specific isozyme expressed at a high level in the adult but not in the fetal or newborn rat. At least seventeen nuclear protein binding sites within the 5'-flanking region extending from -1612 to +243 had been identified by DNase I footprinting analysis and gel mobility shift assays. Among them, one site, GAATTAATAGG, at -669 to -679 is protected from DNase I digestion by nuclear protein from newborn but not from the adult rat brain. The levels of this binding protein, as determined by gel mobility shift assay, were found inversely related to the levels of PKC gamma in rat brain at different stages of development. These results suggest that this particular binding site may participate in the developmental regulation of PKC gamma gene.

Animals↗