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Biomedical subjects

D S Ooi

Publications and source records attributed to D S Ooi.

35 records · Page 2Linked to original sources
PubMed1993

Effects of short-term inhaled budesonide and beclomethasone dipropionate on serum osteocalcin in premenopausal women.

Serum osteocalcin, a marker of bone osteoblast function, has been shown to be sensitive to even low doses of oral glucocorticoids. The effect of 1 wk of inhaled glucocorticoid therapy with budesonide (200 micrograms/puff), beclomethasone dipropionate (250 micrograms/puff), and placebo at two puffs b.i.d. and four puffs b.i.d. on 0900 serum osteocalcin were compared in a double-blind randomized fashion. A two-way repeated-measures analysis of variance showed no main effect of drug or dosage but a significant drug-dose interaction (p = 0.023). Post hoc investigation of this interaction demonstrated that the serum osteocalcin level while taking four puffs b.i.d. (2,000 micrograms) of beclomethasone dipropionate was significantly lower than that of placebo or budesonide at four puffs b.i.d. (1,600 micrograms). These results suggest that at lower doses no acute measurable effect of inhaled glucocorticoids on serum osteocalcin can be appreciated but that at higher doses inhaled beclomethasone dipropionate has a depressant effect on bone osteoblast function.

Administration, Inhalation↗
PubMed1992

Elimination of fibrinogen interference in a dye-binding method for iron.

Serum iron concentrations greater than 90 mumol/L were measured in samples from hemodialysis patients by a Ferrozine dye-binding method. Reanalysis by coulometry showed these results to be spuriously high. Turbidity resulting from precipitation of fibrinogen was identified as the source of the interference. High concentrations of heparin enhanced the effect. We conclude that the persistence of fibrinogen in serum samples from patients treated with anticoagulants is a potential interference in Ferrozine dye-binding methods performed without prior deproteinization. Adding guanidine.HCl to the acid buffer reagent is a simple way to eliminate this interference.

Coloring Agents↗
PubMed1989

Serum human chorionic gonadotrophin levels in early pregnancy.

Serum hCG reference intervals for various gestational periods in normal pregnancies were determined using three commercial assays--two standardized against the WHO 2nd IS (Amersham Amerlex-M beta HCG RIA (AMX) and Abbott beta-HCG 15/15 (ABB] and one standardized against the WHO 1 IRP (Hybritech Tandem -E HCG (HYB]. Serial samples from patients with accurately determined gestational periods were analyzed. We correlated these assays to determine the validity of the common practice of interchanging values between assays using the same WHO standard and of converting 1st IRP values to 2nd IS values by a fixed factor. The slope of correlation between the two 2nd IS assays (AMX, ABB) was 1.43, r = 0.960; whereas between the 1 IRP assay (HYB) and the two 2nd IS assays the slopes were 1.67, r = 0.963 and 1.22, r = 0.971 for AMX and ABB, respectively. In a prospective study of 52 patients with normal pregnancies, serum beta-hCG values in 46% of samples taken at 28-35 days gestation fell below the lower limit of the reference curves supplied with the AMX kit. Ninety-two percent of samples were within the newly established intervals. These results indicate that supplier's reference limits may not be accurate; in addition, a common factor should not be used to convert values from one commercial kit to another.

Adult↗
PubMed1988

A ceramic glazer presenting with extremely high lead levels.

A case of lead poisoning in a ceramic glazer is reported. The patient had an extremely high level of blood lead at 29.5 mumol/l, and many of the laboratory features of lead toxicity: normocytic anaemia with marked basophilic stippling, abnormal blood and urinary porphyrins, and elevated liver enzymes. Surprisingly, the patient had no electromyographic evidence of neurologic involvement. The patient was treated with intravenous EDTA-calcium followed by oral penicillamine. Urinary porphyrin and porphyrin precursor excretion followed an interesting pattern, correlating with the chelator used. This patient illustrates that extremely high blood lead level can be achieved through the oral route in an adult.

Adult↗
PubMed1988

Evaluation of four commercially available assays for free thyroxin.

We assessed two two-step and two analog assays for measuring free thyroxin (FT4) in serum: Clinical Assays' "GammaCoat Free/Total T4" (CA), Vitek's "KinetiCount Phase II Free T4" (VTK), Diagnostic Products Corporation's "Coat-a-Count Free T4" (DPC) kit (June 1987 version), and Amersham's "Amerlex-M Free T4" (AMX). The VTK assay is automated except for the initial pipetting step. Interassay results correlated well except for samples with abnormal serum albumin concentrations. FT4 values for hypoalbuminemic samples showed a highly significant (P less than 0.0001) correlation with serum albumin concentration in the DPC and AMX assays. The relationships are described by the equations y = 0.382albumin (g/L) + 0.81 pmol/L and y = 0.450albumin (g/L) - 3.20 pmol/L, respectively. When we used an equation derived from the Law of Mass Action to adjust FT4 values to values expected at an ideal albumin concentration, the observed correlation of albumin and FT4 was abolished completely in the DPC assay, and partly so in the AMX assay. The precision of CA was comparable with that of the analog assays; the CV for the VTK assay was approximately twice that for the other three assays.

Humans↗
PubMed1983

The value of urinary chloride measurement in distinguishing surreptitious vomiting from Bartter's syndrome.

Urinary chloride measurement is a simple and common procedure but its value in clinical practice is not extensive. This case report highlights a practical and important use of this test. A patient presented with most of the clinical and metabolic derangements of Bartter's syndrome but was found to have extremely low or absent urinary chloride excretion. Her ability to excrete chloride was, however, intact during a chloride load test. The finding of low urinary chloride excretion did not support the diagnosis of Bartter's syndrome and suggested an extrarenal loss of chloride. This was confirmed when she eventually admitted to surreptitious vomiting.

Adult↗
PubMed1981

Serum CK-MB activity during and after aortocoronary bypass surgery.

Frequent serum sampling of CK-MB and total CK levels was carried out in 100 patients during and up to 48 hours following aortocoronary bypass surgery. Using an ion exchange chromatography method for CK-MB determination, significantly higher serum CK-MB levels (peak 46.1 +/- 5.2 cf. 31.3 +/- 2.2 u/L), but not total CK levels were present 6 to 16 hours postoperatively in those with new Q waves in the ECG. Serum levels of CK-MB in those patients with uncomplicated surgery were defined. New post-operative Q waves were seen in only one half of cases with frankly abnormal CK-MB curves and seriously underestimated the incidence of perioperative infarction. Peak levels of CK-MB in patients with new Q waves occurred within 16 hours of surgery suggesting that infarction is usually an intraoperative or early post-operative event.

Chromatography, Ion Exchange↗