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Biomedical subjects

K H Chen

Publications and source records attributed to K H Chen.

At least 73 records · Page 4Linked to original sources
PubMed1993

Effect of protein quality and evaporative cooling on lactational performance of Holstein cows in hot weather.

Twenty-four Holstein cows in midlactation during summer in southern Arizona were fed diets supplemented with a combination of blood, fish, and soybean meals (high quality protein) or corn gluten meal (low quality protein). Diets were balanced for CP content and estimated ruminal protein degradability, but they differed in Lys concentration (.98 vs. .59% of DM). Milk yield for the 56-d trial was higher by 11% for cows fed high than for cows fed low quality protein and higher by 9% for cows receiving evaporative cooling plus shade than for cows receiving shade alone. Milk fat and protein yields also were greater for high than for low quality protein and for evaporatively cooled plus shade than for shade treatments. Intake of DM tended to be higher for cooled cows but was unaffected by protein source. Cooled cows had lower rectal temperatures (38.6 vs. 39.1 degrees C) and respiration rates (64 vs. 82/min) than noncooled cows. Interactions between protein quality and cooling method were not statistically significant; however, cooled cows fed high quality protein had higher milk yield than noncooled cows. Digestibility of DM was higher for the low than for the high quality diet, but CP digestibilities were not different. Cows fed supplemental protein of higher Lys content were more productive.

Animal Feed↗
PubMed1993

Effect of three supplemental fat sources on lactation and digestion in dairy cows.

Tallow, Ca salts of palm fatty acids, or prilled fatty acids were added at 2.5% to a control diet (3.7% fatty acids) containing 7.2% ammoniated whole cottonseed. Diets were fed to midlactation cows (6 cows per treatment) for 72 d to determine effects of fat supplementation and fat source on lactation performance and nutrient digestibilities. Dry matter intake did not differ among treatments. Milk yield was 31.6 kg/d for the control and increased an average of 2.1 kg/d with fat supplementation. Source of supplemental fat did not significantly affect lactation performance. Added fat decreased milk protein content but did not affect protein yield. Milk fat, lactose, and SNF contents did not differ among treatments. Overall fat supplementation did not affect digestibilities of DM, ADF, or NDF but decreased digestibility of fatty acids. Contribution of de novo fatty acids to milk fat was decreased with fat supplementation. Addition of 2.5% fat to a diet containing a medium amount of fat from whole cottonseed increased milk yield. Tallow, Ca salt of palm fatty acids, and prilled fatty acids did not differ in milk yield response.

Adipose Tissue↗
PubMed1993

Hepatitis B virus surface antigen as an interpretation factor for serum biochemical tests in young adults.

With ages between 14-17 years, none of the 2157 subjects studied in the central Taiwan area had ever been inoculated with the hepatitis B vaccine. Whether a hepatitis B virus surface variable, either the hepatitis B surface antigen (HBsAg) or its antibody (anti-HBs), was an interpretation factor in reading laboratory data for a common serum biochemical test was analyzed by two-way analysis of variance (ANOVA). The two independent variables were gender and the hepatitis B surface variable. Either HBsAg or paired HBsAg/anti-HBs was a necessary factor for the seven items:total protein, albumin, total cholesterol, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase. Anti-HBs alone was not an effective agent for the above seven tests and four additional tests, blood urea nitrogen, uric acid, creatinine, and total bilirubin. The analyses yielded no interaction between gender and either hepatitis B surface variable for all tests except uric acid.

Adolescent↗
PubMed1993

Articular manifestations of renal osteodystrophy.

The relationship between hyperparathyroid bone disorders and chronic renal diseases has been studied extensively for a long period of time. Zvaifler and Bywaters are the first to emphasize articular manifestations in hyperparathyroidism. Sundaram has found 30% in 80 hemodialysis patients presenting with articular disorders in hands. We reviewed routine radiographs of 258 uremia patients retrospectively and found that 36 patients had typical X-ray presentations of renal osteodystrophy. Sixteen among them (44.44%) were noted with articular involvement. Fourteen patients involved axial joints including sacroiliac, acromio-clavicular, sternoclavicular and symphysis pubis in decreasing order. Appendicular joints involvement were found in 6 patients, patellofemoral joints and small joints of hands involvement in 4 patients respectively and hip and shoulder joints in each one patient. None of the 16 patients complained joint pain. Diagnosis is easy because of the uncommon presentations of joint disorders in uremic patients. However, more knowledge about articular manifestations of renal osteodystrophy may eliminate the unnecessary investigations.

Adolescent↗
PubMed1992

Southeast Asian mitochondrial DNA analysis reveals genetic continuity of ancient mongoloid migrations.

Human mitochondrial DNAs (mtDNAs) from 153 independent samples encompassing seven Asian populations were surveyed for sequence variation using the polymerase chain reaction (PCR), restriction endonuclease analysis and oligonucleotide hybridization. All Asian populations were found to share two ancient AluI/DdeI polymorphisms at nps 10394 and 10397 and to be genetically similar indicating that they share a common ancestry. The greatest mtDNA diversity and the highest frequency of mtDNAs with HpaI/HincII morph 1 were observed in the Vietnamese suggesting a Southern Mongoloid origin of Asians. Remnants of the founding populations of Papua New Guinea (PNG) were found in Malaysia, and a marked frequency cline for the COII/tRNA(Lys) intergenic deletion was observed along coastal Asia. Phylogenetic analysis indicates that both insertion and deletion mutations in the COII/tRNA(Lys) region have occurred more than once.

Asia, Southeastern↗
PubMed1992

Increased spontaneous release of cytidine deaminase by polymorphonuclear neutrophils of patients with active systemic lupus erythematosus.

Cytidine deaminase activity (CD) in the neutrophil culture supernatants (PMN SUP) of 27 patients with systemic lupus erythematosus (SLE) was measured using a spectrophotometric method. Compared with the controls (5.449 +/- 1.358 U/5 x 10(6) PMN), the CD activity in the spontaneous culture supernatants of PMN was significantly increased in active (10.003 +/- 2.637 U/5 x 10(6) PMN) but not in inactive (5.358 +/- 1.624 U/5 x 10(6) PMN) SLE. However, after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP, 1 x 10(-7) M), the ratio of enzyme activity between stimulated and spontaneous PMN supernatants was decreased in active SLE (0.794 +/- 0.178) compared with normal controls (1.300 +/- 0.225). In contrast, the enzyme activity in the cytoplasm of either stimulated or non-stimulated PMN was not different among these three groups. These results suggest that CD of PMN is releasable and can be enhanced by chemotactic factor stimulation in normal PMN. The increased spontaneous release of CD by active SLE PMN is one of the indicators for the disease activity in these patients.

Adult↗
PubMed1992

Roentgenographic determination of total lung capacity in normal Chinese children.

Roentgenographic determination of total lung capacity (TLC) in children, rarely mentioned in the past, differs from the determination of TLC using helium dilution method in that it does not need the measurement of functional residual capacity. Therefore, it is useful for hospitals where pulmonary function testing (PFT) is not available. In this study, 87 out of 125 normal children completed both chest radiographs and PFT. Ellipsoid method which divides the lung field into several sections was used to calculate TLC from chest radiographs. The correlation coefficient of TLC measured by both chest radiographs and PFT was 0.7680, and paired Student's t-test of the mean values of the two groups showed P value greater than 0.05. Among the variables of height, weight, age and body surface area, height alone was able to predict the normal reference value of TLC. Line of regression between TLC and height was expressed as "TLC = 52.776 x Height- 4404.998", and correlation coefficient was 0.8013. Intersubject reproducibility was also verified. It is concluded that chest radiographs can be used to determine TLC in children.

Adolescent↗
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↗
PubMed1990

Structural organization of the human S-antigen gene. cDNA, amino acid, intron, exon, promoter, in vitro transcription, retina, and pineal gland.

S-Antigen (S-Ag) is a major soluble photoreceptor protein involved in the visual transduction cascade. Several S-Ag cDNAs and a gene coding for human S-Ag were isolated from cDNA and gene libraries. The gene sequences of the coding, noncoding, and 5'-flanking regions of the gene were determined. The S-Ag gene was approximately 50 kbp (kilobase pairs) in length and contained 16 exons and 15 introns. The length of most exons was less than 100 base pairs (bp) and the smallest one was only 10 bp. In contrast, the length of most introns was larger than 2 kbp, and the gene comprised 97% intron and 3% exon. The splice sites for donor and acceptor were in good agreement with the GT/AG rule. The S-Ag protein of 403 amino acid residues was translated from a mRNA of 1.9 kbp, and the mRNA was transcribed from a gene of 50 kbp. The 5'-flanking region of the gene, approximately 1.1 kbp long, had no known regulatory elements for transcription such as TATA, GC, and CCAAT boxes. Interestingly, the 5'-flanking region had promoter activity in an in vitro transcription assay using a nuclear extract of rat brain. A major transcription start site was found at 387 bp upstream from the translation start site ATG. Our results indicate that the sequence of S-Ag promoter differs from other known promoters and may, perhaps, be specific for photoreceptor rod cells and pinealocytes.

Amino Acid Sequence↗
PubMed1990

Characterization of the 5'-flanking region of the rat protein kinase C gamma gene.

The 5'-flanking region of protein kinase C (PKC) gamma gene was identified from a rat liver genomic library in a bacteriophage lambda Charon 4A. A 3.6-kilobase (kb) genomic fragment containing the 5'-flanking region, first exon, and first intron was isolated and sequenced. The transcriptional initiation site, identified by S1 mapping and primer extension, was located 243 base pairs upstream from the translational initiation site. Promoter activity of a DNA segment spanning the 5'-flanking region was demonstrated by both in vitro transcription using HeLa cell nuclear extracts and chloramphenicol acetyltransferase assay by transfection of 293 cells with a PKC gamma-CAT fusion construct. Chloramphenicol acetyltransferase assay revealed that a fragment of about 0.16 kb from the transcriptional initiation site was sufficient for promoter activity in these cells, and the construct containing up to 1.6 kb from the cap site was expressed at a similar level. This promoter-active fragment contains several regions similar to defined transcriptional elements in other mammalian promoters, such as those for stimulatory protein 1 (Sp1), activator proteins 1 and 2 (AP1, AP2), c-myc, cAMP regulatory element-binding protein (CREB), and enhancer core (EnhC). Investigation of the genomic structure of PKC gamma gene may lead to the identification of cis-elements controlling tissue-specific and developmental stage-specific expression of PKC gamma.

Animals↗
PubMed1989

The clinical significance of human immunodeficiency virus type 1-associated paraproteins.

We observed and characterized paraproteins present in the serum of seven human immunodeficiency virus type 1 (HIV-1)-infected individuals. Immunoglobulin (Ig) subclass typing performed on these paraproteins identified five as IgG1 kappa, one as an IgG3 lambda, and one as an IgA lambda. The IgG1 kappa paraproteins, purified by high-pressure liquid chromatography, contained the majority of anti-HIV-1 antibody reactivity present in the five serum specimens (ranging from 1:5,000 to 1:500,000) as demonstrated by immunoblot. All five IgG1 paraproteins had at least two light chain species as demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the antibodies were reactive with multiple HIV-1 viral antigens. In contrast, the electrophoretically purified IgG3 lambda and IgA lambda paraproteins did not react with HIV-1 antigens and only one light chain species was detected by SDS-PAGE. The subsequent clinical evaluation of these patients following the initial observation of paraproteinemias failed to correlate the presence of paraproteins with the development of lymphoma over a 2 to 3 year period. These data support the hypothesis that IgG1 paraproteins present in the sera of HIV-1 infected individuals reflect a normal albeit exuberant polyclonal immune response to HIV-1 viral antigens. In contrast, the clinical significance of an IgG3 lambda or an IgA lambda paraprotein is unclear at present.

Antibody Specificity↗
PubMed1988

A Rapid and Simple Procedure for Purification of Indole-3-Acetic Acid Prior to GC-SIM-MS Analysis.

A simple and rapid procedure for the purification of indole-3-acetic acid prior to gas chromatography-selected ion monitoring-mass spectrographic analysis was developed using an amino anion exchange minicolumn and a short high resolution C18 column. Since multiple samples can be prepared at one time, the procedure is more rapid and the sample preparation time is reduced to one-third that normally required. In addition, the final recovery was improved by 40 to 50% over that of a solvent partitioning procedure.

Journal Article↗
PubMed1987

Improvement in the resolution of o-phthalaldehyde derivatized amino acids by applying gradient steepness optimization to five reversed-phase columns of different lengths and particle sizes.

Twenty-two o-phthalaldehyde (OPA) derivatized amino acids were separated on five different reversed-phase, octadecyl columns. Each column was packed with the same type of spherical silica on which matched bonding chemistry had been performed. Columns of 250, 150 or 50 mm x 4.5 mm I.D. were packed with 5 microns particles, and columns of 100 or 50 mm x 4.5 mm I.D. were packed with 3 microns particles. Snyder's linear solvent strength gradient optimization method was used to determine the optimum gradient steepness by maximizing the resolution of four pairs of adjacent OPA-derivatized amino acids. An asymptotic dependence of improvement in resolution with increase in gradient time was obtained for each pair of compounds on each column. For short (50 mm) columns, resolution of very closely eluting compounds required the use of gradient steepness parameters as low as 0.05 and 0.02, due to the low efficiencies intrinsic to these short column lengths.

Amino Acids↗
PubMed1987

Immunofixation compared with immunoelectrophoresis for the routine characterization of paraprotein disorders.

The authors prospectively compared immunofixation electrophoresis (IFE) with immunoelectrophoresis (IEP) for the evaluation of paraproteins in 32 patient specimens. They used a simple modification of their existing agarose protein electrophoresis system for IFE. Thirteen specimens (40%) required IFE for paraprotein identification, 18 (56%) were definitive by either method, and 1 (3%) did not show a paraprotein by either method. Low titer and/or avidity with anti-lambda antibody from three of seven suppliers prevented or complicated interpretation of IEP patterns with two of four known lambda paraprotein-containing specimens but had no such effect with IFE. In view of these and various additional technical considerations, the authors suggest IFE for the routine characterization of paraproteins in the serum or urine.

Blood Protein Electrophoresis↗