Biomedical subjects
H J Tan
Publications and source records attributed to H J Tan.
Rheumatoid pachymeningitis.
Symptomatic rheumatoid pachymeningitis is a rare extra-articular manifestation of rheumatoid arthritis. Clinical symptoms are non-specific and diagnosis is frequently made by exclusion. We present a 61-year-old woman with a 9-year history of rheumatoid arthritis presenting with deafness and progressive disability over a two month duration. She was diagnosed as having rheumatoid pachymeningitis based on the cerebral magnetic resonance imaging findings.
Ultrasonography is not reliable in diagnosing liver cirrhosis in clinical practice.
BACKGROUND: The diagnosis of liver cirrhosis is important in the evaluation and management of patients. Liver biopsy is the gold standard but it is invasive. Ultrasonography is a non-invasive and useful modality in assessing the liver for certain conditions but its sensitivity and specificity in diagnosing cirrhosis is unknown locally. AIM: To assess the accuracy of ultrasonography in diagnosing compensated liver cirrhosis in daily clinical practice outside the context of clinical trials. METHODS: All the liver biopsies were identified from the Pathology Logbook retrospectively from January 1998 to March 2001. Only patients who had both liver biopsy and ultrasonography with no clinical evidence of cirrhosis were included. Patients with incomplete data, hepatoma or liver secondaries were excluded. Ultrasonographic diagnosis of cirrhosis was based on nodularity or irregularity of the liver surface, small liver size, coarse echotexture and increase attenuation by using the 3.5 to 5 MHz transducers. RESULTS: A total of 151 liver biopsies were performed during this period. Eighty-eight patients who had both ultrasound and liver biopsy were analysed. Seventeen patients had ultrasonographic diagnosis of cirrhosis but only six cases were proven by a liver biopsy. On the other hand, 10/16 cases of biopsy-proven cirrhosis were "missed" by ultrasound. Thus, the sensitivity of ultrasonography in diagnosing cirrhosis was 37.5% and the specificity was 84.7%. The positive and negative predictive values were 35.3% and 85.9% respectively. CONCLUSION: Low frequency ultrasonography is not a sensitive test for the diagnosis of liver cirrhosis in daily clinical practice.
An unusual rash and end-stage renal failure.
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[Review on studies of external treatment of skin ulceration with Chinese herbal medicine].
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Drug-induced oesophageal injury.
Drug-induced oesophageal injury is probably more common than previously thought. It is a major cause of morbidity and in some cases mortality. This article reviews the studies over the years, looking at factors affecting the transit time of pills, injury caused and ways to prevent it, and highlights the salient points with a case study.
Electrophysiological properties of frog spinal dorsal horn neurons and their responses to serotonin: an intracellular study in the isolated hemisected spinal cord.
Frog dorsal horn neurons and their responses to serotonin (5-HT) were studied in intracellular recordings from isolated hemisected spinal cords. Electrophysiological properties were comparable to those of mammals. Bath application of 5-HT (10-50 microM) increased the excitability and caused membrane depolarizations in 7/14 cells, reduced or abolished activity and caused hyperpolarizations in 4 neurons, exerted a biphasic effect in two cells, and produced no detectable change in one neuron. The multiple effects of 5-HT may be mediated through different 5-HT receptor subtypes.
Bulbospinal serotoninergic pathways in the frog Rana pipiens.
We combined retrograde fluorescent tracing with rhodamine immunofluorescence to identify the origin of serotoninergic neurons with descending projections to the spinal cord of frogs. After injections of Fluoro-gold into the spinal cord, retrogradely labeled immunoreactive serotoninergic neurons were detected in the caudal part of the brainstem from the level of the obex through the level of the VIII nerve. These doubly labeled cells were distributed along the midline throughout the rostrocaudal extent of the dorsal portion of the raphe nuclear region. Doubly labeled neurons were more numerous in the rostral than in the caudal part of the raphe area. The fluorescent tracer 1,1'-dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine perchlorate (DiI) was then placed in and around the middle and rostral raphe nuclear region. Anterogradely labeled fibers could be traced bilaterally in the lateral portion of the dorsal funiculus and the lateral and ventral funiculi. These fibers were seen terminating in the dorsal and ventral horns, as well as in the intermediate grey matter. After placement of DiI in the caudal raphe area, labeled fibers were found only in the intermediate grey and ventral horn. These findings suggest that the organization of bulbospinal serotoninergic pathways in the frog is similar to that of mammals, and that an isolated amphibian spinal cord preparation could be a useful model for pharmacological and physiological studies of the action of serotonin (5HT) in the spinal cord.