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H H Lim

Publications and source records attributed to H H Lim.

63 records · Page 4Linked to original sources
PubMed1981

Filarial enzymes by the horizontal starch-gel electrophoresis technique.

In preliminary studies, on adult filarial parasites, difference in the electrophoretic pattern of glucosephosphate isomerase (GPI) of B. malayi, B. pahangi and the rat filarial worm, B. booliati, was demonstrated. There also appears to be a difference in the GPI and lactate dehydrogenase isoenzyme patterns of B. malayi (subperiodic) from different animal hosts. These observations suggest that the zymogram technique may yet prove to be a sensitive taxonomic tool for use in the characterisation of filarial helminths. At present, the contention is that the subperiodic form of B. malayi exists as a zoonoses (possibly also with B. pahangi), which is drawn from findings backed by procedures that cannot easily differentiate between closely-related species and subspecies. Thus enzyme electrophoresis could complement the parasitological methods currently used, and contribute in enhancing the validity of this contention. More work, and on a larger scale to include the microfilariae and infective larvae, would be required.

Animals↗
PubMed1977

Determination of ethanol in serum by an enzymatic PMS-INT colorimetric method.

A simple, rapid and accurate colorimetric method for the determination of ethanol in serum was studied. Ethanol is converted to acetaldehyde by alcohol dehydrogenase, and the NADH formed transfers its hydrogen through the phenazine methosulphate-p-iodonitrotetrazolium violet (PMS-INT) system to produce the red formazan which is stable and absorbs at 505 nm. The method correlates very well with an enzymatic-UV method, r=0.98 (p less than 0.001). The precision (95% limits) of the method for samples ranging from 11 to 145 mg/dl was +/-6.6%, and the recovery averaged 99%.

Colorimetry↗
PubMed1976

The use of NADH as a standard in a modified PMS-INT colorimetric assay of lactate dehydrogenase.

A new and more reliable way of quantitating lactate dehydrogenase activity, using NADH as a standard in a colorimetric assay, is proposed. Adopting the scheme, we obtained a CV of 2.6% and precision (95% limits) of +/-5.4% for enzyme activities ranging from 110 to 600 U/l. Comparative study against the modified kinetic method of Amador et al. showed excellent correlation, r = 0.99, p less than 0.001. A normal range of 75 to 203 U/l was determined for the proposed scheme.

Colorimetry↗
PubMedDate not supplied

Life and death cell labeling in the microcirculation of the spontaneously hypertensive rat.

Spontaneously hypertensive rats (SHRs) have elevated numbers of apoptotic cells. However, the extent and pattern of cell death at the microvascular level is unexplored. We developed a technique to determine early forms of cell death in vivo in the mesentery by use of the life/death indicator ethidium bromide (EB). The mesenteric microvasculature was superfused with 5 microM EB for a period of 3 min, rinsed and immediately viewed by digital fluorescence microscopy. EB-positive cell structures were observed both in the wall of microvessels as well as in the tissue parenchyma. The microvessels had about 2--4 EB-positive cell structures per 100 microm of vessel length. Larger arterioles (>25 microm) in the SHR had an increased EB-positive structure density. After normalization of the blood pressure in the SHR with adrenalectomy, no significant differences remained between Wistar-Kyoto (WKY) rats and SHRs. After dexamethasone treatment, the adrenalectomized SHRs had a higher EB-positive cell density in the smaller class of microvessels than the WKY rats. In addition, EB-positive cell fragments (0.5--2 microm) were observed in the mesentery microvessel wall, and with TUNEL labeling, they were demonstrated to represent DNA fragments. The percentage of microvessels with EB-positive fragments was higher in the SHR arterioles and capillaries. Capillaries and larger venules (>30 microm) in the SHR had higher levels of cell fragments per vessel length. After adrenalectomy, no significant differences remained between WKY rats and SHRs in any of the microvessel categories. When adrenalectomized rats were treated with dexamethasone, a higher number of EB-positive fragments was detected in the wall of SHR capillaries. These results indicate that the mesentery microcirculation in both strains is subject to an early and nonuniform pattern of cell death, as detected by EB, but is enhanced in selected individual microvascular segments of the SHR by a glucocorticoid-driven mechanism.

Adrenalectomy↗