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Biomedical subjects

R Heng

Publications and source records attributed to R Heng.

6 recordsLinked to original sources
PubMed2006

Managing peripherally inserted central catheter-related venous thrombosis: How I do it.

Imaging-guided insertion of central venous catheters, either in the form of a peripherally inserted central catheter (PICC) or through a subclavian or a jugular approach, is becoming the preferred method of acquiring long-term venous access for a variety of therapeutic purposes. The most significant complication from central venous catheters is thrombosis of the catheterized vein. Venous thrombosis related to the insertion of PICC lines is conventionally treated with line removal followed by anticoagulation. Direct thrombolysis with urokinase, using the lumen of the PICC line to facilitate the insertion of the infusion catheter is a simple, safe and effective treatment option. In this article, we describe our experience with this procedure and the technique used.

Adult↗
PubMed1996

The field testing of Denver Developmental Screening Test Singapore: a Singapore version of Denver II Developmental Screening Test.

The Denver Developmental Screening Test, Singapore (DDST, Singapore), a Singapore version of the Denver II Developmental Screening Test, was field-tested, using trained staff nurses as testers, on 2459 children (known cases excluded), in 5 key ages of 3 months, 9 months, 17 months, 37 months and 60 months. Only 2.6% (65) of the parents suspected developmental problems in their children before screening. Taking children with "questionable" (7.2%), "abnormal" (3.7%) and "untestable" (1.7%) scores as the screened-out cases, the DDST, Singapore had a screened-out rate of 12.6%. A total of 171 screened-out cases and 168 "normal" children were also evaluated by the Development Assessment Clinic (DAC) of the Singapore General Hospital and the results were compared in these 2 groups of children. Among the screened-out cases, 16.6% were confirmed or suspected to have neuro-developmental disorders (NDDs) by the DAC. The computed NDD rate in the study sample was 5.3%. Based on a single DDST, Singapore test result, there was a high false positive rate of 83.5% and lower false negative rate of 3.7% compared to the DAC assessment. However, the high false positive rate would be significantly reduced by doing a repeat screening test on the "questionable" cases and having the screened-out cases assessed by trained primary health care doctors. In conclusion, no major revision is needed in the scoring criteria suggested in the current version of DDST, Singapore. It is a useful tool in identifying children who will otherwise be missed without formal screening.

Child, Preschool↗
PubMed1995

Expression, refolding, and autocatalytic proteolytic processing of the interleukin-1 beta-converting enzyme precursor.

The interleukin-1 beta-converting enzyme is a heterodimeric cysteine protease that is produced as a 45-kDa precursor. The full-length precursor form of the enzyme was expressed in Escherichia coli as insoluble inclusion bodies. Following solubilization and refolding of the 45-kDa protein, autoproteolytic conversion to a heterodimeric form containing 10- and 20-kDa subunits was observed. This enzyme had catalytic activity against both natural (interleukin-1 beta precursor) and synthetic peptide substrates. The inclusion of a specific inhibitor (SDZ 223-941) of the converting enzyme in the refolding mixture prevented proteolytic processing to the 10-/20-kDa form. Similarly, refolding under nonreducing conditions also prevented processing. Time course experiments showed that the 10-kDa subunit was released from the 45-kDa precursor before the 20-kDa subunit, implying that the N-terminal portion of the precursor is released last and may play a regulatory role.

Amino Acid Sequence↗
PubMed1995

Reduction of inflammation and pyrexia in the rat by oral administration of SDZ 224-015, an inhibitor of the interleukin-1 beta converting enzyme.

1. The aim of this study was to determine whether a synthetic inhibitor of the interleukin-1 beta converting enzyme (ICE) displays oral activity in models of inflammation. 2. To this end, the ICE inhibitor, SDZ 224-015, was examined in rat paw oedema, pyrexia and nociception tests. 3. SDZ 224-015 (0.3-300 micrograms kg-1) potently reduced carrageenin-induced paw oedema, with an oral ED50 of approximately 25 micrograms kg-1. This effect was independent of endogenous glucocorticoid, as shown by retention of activity upon adrenalectomy. 4. Pyrexia induced by lipopolysaccharide (0.1 mg kg-1 s.c.) or by interleukin-1 beta (100 ng i.v.) was also reduced, over a similar dose-range to oedema (oral ED50s 11 micrograms kg-1 and 4 micrograms kg-1 respectively). 5. SDZ 224-015 (0.2-5 mg kg-1, p.o.) displayed analgesic activity in the Randall-Selitto yeast-inflamed paw pressure test, significant at a dose of 1 mg kg-1, p.o. 6. Thus, SDZ 224-015 has potent oral activity in several acute models for inflammation, suggesting that ICE inhibitors may constitute a novel type of anti-inflammatory agent.

Administration, Oral↗