Search PubMed⌕ Search

Biomedical subjects

M C Chung

Publications and source records attributed to M C Chung.

At least 73 records · Page 4Linked to original sources
PubMed1996

Bestatin analogue from Streptomyces neyagawaensis SL-387.

A bestatin analogue, (2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl-L-valine (AHPA-Val), from the culture filtrate of Streptomyces neyagawaensis SL-387 was obtained in a chemically defined medium containing DL-3-amino-3-phenylpropionic acid. AHPA-Val was 6 times (IC50 = 1.2 micrograms/ml) as strong as bestatin (IC50 = 7.0 micrograms/ml) against porcine kidney microsomal aminopeptidase N, and 4 times (5.6 micrograms/ml) as strong as bestatin (IC50 = 20.7 micrograms/ml) against aminopeptidase N of human metastatic fibrosarcoma HT1080. To the best of our knowledge, this is the first report on the microbial production of AHPA-Val.

Amino Acids↗
PubMed1996

Communication skill and behaviour disorder.

The aim was to identify changes in communication skills and behaviour disorder of 15 clients with learning difficulties 6 mo. and 1 yr. after they moved from large- to small-scale accommodations. Clients were allocated into a group of 6 with profound multiple learning difficulties, a preverbal group of 5, and a verbal group of 4. Communication skills were measured using the Preverbal Communication Schedule, and behavioural disorder was measured using the Aberrant Behaviour Checklist. Analysis showed that from the baseline to one year follow-up, there was a significant increase from baseline in social withdrawal by the clients with multiple difficulties but that there were improvements in communication skills of both preverbal and verbal clients. No control group was involved.

Adult↗
PubMed1996

A preliminary study on the prevalence of challenging behaviours.

The purpose of this study was to estimate the prevalence of challenging behaviour among subjects with learning disabilities in an English health district. Subjects' disabilities included incontinence, lack of communication skills, and need of assistance with domestic activities, feeding, washing, and dressing. Some also had physical impairments. The most common behaviours were hyperactivity and irritability and the most common psychiatric disorders included severe anxiety, affective disorder, and adjustment disorder.

Activities of Daily Living↗
PubMed1996

Causes of age-related decline in adaptive behavior of adults with Down syndrome: differential diagnoses of dementia.

Although a decline in adaptive behavior with age in adults with Down syndrome has been established, the underlying causes of the decline remain unresolved. Differential causes of the decline in 201 adults with Down syndrome were investigated. Aging, dementia, and severity of mental retardation were found to be significant factors. Absence of a medical illness was a factor that predicted a higher level of adaptive behavior. No significant difference in age-related maladaptive behaviors was found. However, a clinical diagnosis of dementia was a predictive factor for increased maladaptive behavior. Clinical implications of these findings were discussed.

Adolescent↗
PubMed1995

Ketone reductase activity and reduced haloperidol/haloperidol ratios in haloperidol-treated schizophrenic patients.

Twenty schizophrenic patients were treated with a fixed haloperidol (HL) dose of 20 mg/day for 4 weeks. The conversion of HL to its reduced metabolite (reduced haloperidol, RH) occurs via the ketone reductase enzyme. RH is also converted back to HL by the cytochrome P450 2D6 isozyme. Ketone reductase activity can be measured in red blood cells. Plasma HL and RH levels were assayed by high performance liquid chromatography. Blood samples were obtained at baseline and during weeks 2 and 4 of HL therapy. Seventeen of 20 patients had ketone reductase values < 3. A significant correlation between ketone reductase and RH/HL plasma ratios was observed at week 4 in these 17 patients. Patients with ketone reductase activity < 3 could represent a subgroup of patients that metabolize HL differently. The wide interpatient variability observed with HL and RH plasma levels in HL-treated patients could reflect differences in ketone reductase activity and the metabolic status of debrisoquin hydroxylase (cytochrome P450IID6) in psychiatric patients.

Adult↗
PubMed1995

Purification and characterization of two forms of cytochrome b5 from an arachidonic acid-producing fungus, Mortierella hygrophila.

Two forms of cytochrome b5 have been purified from the microsomes of an arachidonic acid-producing fungus, Mortierella hygrophila IFO 5941, after detergent solubilization. They have monomeric molecular masses of about 16 kDa and 19 kDa. Their absorption spectra are similar to those of mammalian cytochrome b5s. Their amino acid compositions show some similarity to those of mammalian cytochrome b5s, but the contents of some amino acids (glycine, alanine, aspartic acid + asparagine, glutamic acid + glutamine, arginine, proline, histidine, leucine and lysine) are unique to the cytochrome b5s of M. hygrophila. Some of their internal peptide sequences also show close homology with those of some mammals (approx. 65 to 67%), while some others show no or little homology. The addition of various acyl-CoAs to NADH-reduced microsomes caused an abrupt shiftdown of the steady state reduction level of cytochrome b5. This indicates the increased utilization of electrons for the desaturation process and may suggest that the cytochrome b5s of this fungus actually take part in its microsomal desaturation system for polyunsaturated fatty acid biosynthesis as electron carriers.

Amino Acid Sequence↗
PubMed1995

A serotype-specific epitope of dengue virus 1 identified by phage displayed random peptide library.

From a panel of monoclonal antibodies of dengue viruses, a serotype-specific epitope of dengue virus 1 was screened from a random peptide library displayed on phage. The epitope was the determinant reactive with monoclonal antibody 15F3-1 that was specific to dengue 1. The screening was monitored by a dot blotting procedure, and after three rounds of screening a consensus motif, HRYSWK, was found. This sequence matches the sequence HKYSWK, corresponding to the amino acid residues 885-890 of polyprotein or residues 111-116 of the non-structural protein 1 of dengue virus serotype 1. The linear epitope was confirmed by testing the antigenicity of chemically synthesized 8-branched peptide.

Amino Acid Sequence↗
PubMed1995

Analysis of recombinant human tumor necrosis factor beta by capillary electrophoresis.

Capillary electrophoresis was used for the analysis of recombinant human tumor necrosis factor beta (rhTNF-beta). Reproducible separation of the protein could be achieved in Polybrene-coated capillaries. Optimum conditions for separation were achieved with a pH 4.5 sodium acetate buffer. Besides Polybrene-coated capillaries, other commercially available column and column-coating reagents were also examined for the separation of rhTNF-beta. Capillary electrophoresis was found to be a potentially useful method for product analysis and process monitoring in recombinant-DNA technology.

Electrophoresis↗
PubMed1995

Epitope identification by polyclonal antibody from phage-displayed random peptide library.

Screening of bioactive peptides from random peptide libraries using monoclonal antibodies as ligates is an effective method to define epitopes of protein antigens. However, it is thought that polyclonal antibodies might also serve as promising ligates for screening. We illustrate this approach by using recombinant human lymphotoxin (rhLT) polyclonal antibody as a model. The procedure consists in (a) affinity purification of polyclonal antibody to obtain the "monospecific" antibody, (b) screening against a phage-displayed random peptide library using the affinity-purified antibody, (c) plating the enriched phage on agar plates, randomly picking clones, and selecting the positive ones by dot blotting, (d) DNA sequencing of the positive clones and conducting a homology search against the protein sequence databank, and (e) confirming the epitopes by chemical peptide synthesis. By employing this procedure, we identified a dominant epitope RQHPKM, located at residues 15-20 of the human lymphotoxin amino acid sequence. The usefulness of this general procedure is discussed.

Amino Acid Sequence↗
PubMed1995

Quality assurance and the myth of rationality.

Examines the extent to which quality assurance can be conceived as a rational endeavour, particularly in ethical terms. Examines the Weberian distinction between rationality as values as an "end in themselves" and values conceived in terms of a "means-ends" distinction. While the emergence and existence of quality assurance can be viewed from either of these two perspectives, both entail a number of problems. Suggests that quality assurance, while appearing rational, fails at a crucial point for two reasons. First, while rationality is a relational concept, quality within the health service does not appear to function in such a manner; and second that quality assurance often neglects to evaluate its own activities. Claims that in both instances quality assurance acts more in terms of its functional role than in terms of its rationality.

Ethics, Medical↗
PubMed1995

Podiatric disorders among children with Down syndrome and learning disability.

This study investigated podiatric pathology in seven- to 14-year-old children with Down syndrome (DS) and non-Down syndrome learning-disabled and non-learning-disabled age-matched controls. Several conditions, including pes planus, fissures, split toenails, increased plantar flexed first ray and a wide hallucal cleft were found to be more common in the DS group. Pes cavus and foot rigidity were more common in the non-DS learning-disabled group. In all groups the majority of children wore laced shoes, which were most ill-fitting among children with a learning disability. Approximately one-third in each group had abnormal foot-pressure prints. Greater care and professional awareness of podiatric pathology in children with learning disability is recommended.

Adolescent↗
PubMed1995

Classification of psychotic symptoms in dementia sufferers.

Little attention has been payed to the classification of psychotic symptoms in dementia sufferers. This article compares the etiology of delusions, visual hallucinations and delusional misidentification and examines the value of factors generated from principal components analysis as a possible classificatory system in a group of 125 patients with DSM-III-R dementia in contact with clinical services who were prospectively evaluated using standardized instruments to describe in detail individual psychotic symptoms. The assessment also included the Geriatric Mental State Schedule, the History and Aetiology Schedule and the CAMCOG. Delusions and visual hallucinations had a distinct cognitive profile as did delusions and delusional misidentification, although there was an overlap between visual hallucinations and delusional misidentification. Four factors were generated from principal components analysis. Three of these closely mirrored the 3 symptom groups delusions, visual hallucinations and delusional misidentification, although the phantom-boarder delusion was correlated with the visual hallucination factor and not delusional misidentification. The fourth factor included visual hallucinations of relatives and delusions that relatives were in the house. This factor was strongly inversely associated with emotional distress and could perhaps best be seen as a comfort phenomena. The pattern of cognitive deficits and etiological associations of each of the factors were independent of one another, supporting the notion that it is useful to consider them as separate entities.

Aged↗
PubMed1995

BamHI and HindIII repetitive DNA families in the rice genome.

In this paper we describe a novel method of cloning representative members of different repetitive DNA families based on the screening of a rice (Oryza sativa) genomic library using DNA from different C0t fractions as probes. Two genomic clones, which represent two different repetitive DNA families in rice, were isolated by this method and have been characterized. Their nucleotide sequences, copy numbers, distributions in major rice genome types, methylation patterns, and chromosomal localizations were determined.

Base Sequence↗
PubMed1995

Differences in attitudes among medical students towards psychiatry in one English university.

Responses of 146 medical students in the final academic year on the Attitudes Towards Psychiatry Questionnaire were obtained before and after the clerkship in psychiatry. While there were no significant differences between the 57 men and 89 women, students' image of psychiatrists did not change but several initially held attitudes about psychiatric practice and training improved following the clerkship.

Adult↗
PubMed1994

Thermostable N-carbamoyl-D-amino acid amidohydrolase: screening, purification and characterization.

A thermostable N-carbamoyl-D-amino acid amidohydrolase was found in the cells of newly isolated bacterium. Blastobacter sp. A17p-4. The bacterium also showed D-specific hydantoinase activity. The N-carbamoyl-D-amino acid amidohydrolase activity of the cells exhibited a temperature optimum at 50-55 degrees C, and was stable up to 50 degrees C. The N-carbamoyl-D-amino acid amidohydrolase of Blastobacter sp. A17p-4 was purified to homogeneity and characterized. It has a relative molecular weight of about 120,000 and consists of three identical subunits with a relative molecular weight of about 40,000. N-Carbamoyl-D-amino acids having hydrophobic groups served as good substrates for the enzyme. It has been suggested that D-amino acid production from DL-5-substituted hydantoin involves the action of a series of enzymes involved in pyrimidine degradation, namely amide-ring opening enzyme, dihydropyrimidinase, and N-carbamoylamide hydrolyzing enzyme, beta-ureidopropionase. However, the purified enzyme did not hydrolyze beta-ureidopropionate; suggesting that the N-carbamoyl-D-amino acid amidohydrolase coexisting with D-specific hydantoinase, probably dihydropyrimidinase, in Blastobacter sp. A17p-4 is different from beta-ureidopropionase.

Amidohydrolases↗
PubMed1994

Antibody against branched epitope as an affinity ligand to separate the parent protein.

A peptide that contained one of the continuous epitopes of recombinant human lymphotoxin (rhLT) (amino acid residues 139-154) has been located by epitope mapping. The branched form of this peptide was synthesized by the multiple antigen peptide procedure with an octameric branched resin and was subsequently used to elicit anti-epitope antibody in rabbits. The resulting anti-epitope was then used as an immunoaffinity ligand in affinity chromatography to purify the parent protein, rhLT, from the host cell lysate directly. It is suggested that this approach would be a general way to create novel biospecific ligands for affinity separations.

Amino Acid Sequence↗