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Biomedical subjects

B Yip

Publications and source records attributed to B Yip.

61 records · Page 4Linked to original sources
PubMed1992

Plasma triglyceride and low density lipoprotein metabolism.

This study examines the relationship between plasma triglyceride and low density lipoprotein (LDL) levels by measuring the turnover of the native and 1,2 cyclohexanedione-treated lipoprotein in 25 healthy adults. Plasma triglyceride showed a strong positive correlation with circulating LDL apoprotein (apo LDL) mass. In order to achieve a satisfactory fit to the kinetic data it was necessary to postulate the existence of two plasma apo LDL pools (A and B). When subjects were grouped in quintiles on the basis of circulating apo LDL mass, pool A predominated in those in the lowest quintile. The fractional catabolic rate (FCR) of apo LDL from this pool was high (FCR = 0.57 +/- 0.06 pools day-1). As plasma triglyceride and apo LDL mass rose, apoprotein accumulated in the more slowly metabolized pool B as a result of an increase in the rate of input of apo LDL into the latter. The fractional clearance rate of protein from this pool remained unchanged at 0.26 +/- 0.04 pools day-1. Synthesis of apo LDL into pool B correlated with plasma triglyceride (r = 0.553, P less than 0.01), suggesting that the protein in this pool was derived from large, triglyceride-rich very low density lipoprotein.

Adult↗
PubMed1991

Molecular defects in haemophilia B: detection by direct restriction enzyme analysis.

The common restriction fragment length polymorphisms (RFLPs) associated with the FIX gene: 5' BamH I, Dde I, BamH I (2), Taq I and 3' Hha I were absent or of low incidence in Southern Chinese and are therefore not useful for linkage analysis. No deletion was detected amongst seven consecutive unrelated haemophilia B patients, but one had an insertion of a 15 kb Pvu II fragment containing exon d. Using an alternate strategy of polymerase chain reaction (PCR) amplification and direct sequencing, the molecular defect in the other six patients was defined. The four novel mutations characterized were: nucleotide (nt) 6410 G----C (Gly12----Ala); nt 31261 delta T (stop codon 31 bp downstream); nt 31260 C----G (Thr380----Ser) and nt 31122 C----A (Ala34----Asp). Two patients had the same mutation at nt 6365, G----A (Arg-4----Gln), identical to one previously described in other ethnic groups, suggesting that this is a hotspot for mutation. Each of the mutations was found to affect an enzyme recognition site and could thus be identified by direct visualization of abnormal restriction fragments in amplified genomic DNA. This allows rapid and accurate DNA diagnosis of haemophilia B in an ethnic group which otherwise shows little or no polymorphism for the common RFLP sites.

Blotting, Southern↗
PubMed1990

Rapid isolation of low density lipoprotein (LDL) subfractions from plasma by density gradient ultracentrifugation.

High resolution density gradient ultracentrifugation (DGUC) and non-denaturing gradient gel electrophoresis (GGE) indicate that low density lipoprotein (LDL) in both normal and hyperlipidaemic subjects is composed of overlapping particle populations. A new centrifugation procedure has been developed which permits the separation of LDL subspecies directly from plasma within 24 h. The profiles obtained were analogous to those seen on gradient gel electrophoresis. LDL was divided into 3 fractions. The plasma concentration of LDL-I seen in young females was twice that in men (85.6 +/- 28.8 vs. 42.3 +/- 25.7 mg/dl, P less than 0.005). LDL-II was not significantly different in any group while LDL-III was specifically elevated in coronary artery disease (CAD) patients (207.1 +/- 92.6 mg/dl in CAD vs. 87.4 +/- 79.6 mg/dl in normal men, P less than 0.05). The presence of small, dense LDL detected either by density gradient centrifugation or gel electrophoresis was associated with raised triglyceride (TG) and low high density lipoprotein (HDL) cholesterol and may be a risk marker for coronary artery disease.

Adolescent↗
PubMed1986

Serum gastrin level is increased by chronic hypercalcemia of parathyroid or nonparathyroid origin.

In patients with hypercalcemia with abdominal symptoms, gastrin concentration is often measured to exclude the Zollinger-Ellison syndrome. We found that interpretation of such measurements is clouded by a contradictory literature. We therefore measured serum gastrin concentrations in 78 patients with primary hyperparathyroidism, 36 with nonparathyroid hypercalcemia, 13 with hypocalcemia, and 33 normocalcemic controls. Gastrin values above normal occurred in 22% of those with primary hyperparathyroidism and 28% of those with nonparathyroid hypercalcemia. Values above 250 pg/mL occurred only in those with hypochlorhydria or multiple endocrine neoplasia, type 1 (MEN 1). After parathyroidectomy, gastrin levels fell significantly, but elevated values tended to recur in those with MEN 1 if hypercalcemia recurred. Thus, chronic hypercalcemia of either parathyroid or nonparathyroid origin may elevate serum gastrin concentrations, but marked elevations suggest either achlorhydria or MEN 1.

Adult↗
PubMed1976

The kinetic mechanism of rat kidney gamma-glutamylcysteine synthetase.

A detailed kinetic investigation was made of the binding mechanism of gamma-glutamylcysteine synthetase purified from rat kidney. The results of initial rate and inhibition studies are consistent with a partially random mechanism in which ATP is the obligatory first substrate and both amino acids bind in a random order to the enzyme-ATP complex. Formation of the enzyme-substrate quaternary complex is necessary prior to release of products. This mechanism is consistent with previous binding studies with the enzyme and while it does not rule out participation of enzyme-bound gamma-glutamyl phosphate as an intermediate in catalysis, such an intermediate cannot be a discrete covalent complex.

Adenosine Diphosphate↗
PubMedDate not supplied

Oral health in elderly patients.

A study of the oral health of elderly institutionalised patients and their oral care has revealed significant deficiencies, illustrating the need for a multi-disciplinary approach to oral health care centred on the development of mouth care regimens for nursing staff.

Aged↗