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Biomedical subjects

Y H Chan

Publications and source records attributed to Y H Chan.

97 records · Page 6Linked to original sources
PubMed1976

Cyclic nucleotide phosphodiesterase activity of human normal and carcinomatous lung tissue.

The activity of the phosphodiesterase enzyme(s) responsible for the degradation of cylic adenosine monophosphate (CA.M.P.) and cyclic guanosine monophosphate (CG.M.P. (in human normal and carcinomatous lung tissue has been investigated. Enzyme activities were 3-5 times greater in normal than in carcinomatous lung. This is compatible with the known higher concentrations of these cyclic nucleotides in normal tissues. It is suggested that cancer chemotherapy designed to block the phosphodiesterase activity, and thus promote accretion of CA.M.P and CG.M.P., may provide a means of normalising cancerous tissue. Both phosphodiesterase activities in both types of tissue were inhibited by methylxanthines at 10(-3) mol/l, but some enzyme potentiation was observed at lower concentration.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMedDate not supplied

Distribution of mucosal pH on the bucca, tongue, lips and palate. A study in healthy volunteers and patients with lichen planus, Behçet's disease and burning mouth syndrome.

Saliva coating all oral surfaces has a buffering capacity that neutralizes bacterial and cariogenic acids. The aim of our study was to determine the surface pH in different regions of the oral cavity in healthy volunteers and in patients with diseases affecting the oral mucosa. Oral pH was measured with a flat glass electrode on the anterior third of the ventral surface of the tongue, middle hard palate, buccal mucosa and inner lips in 32 healthy volunteers, 12 patients with Behçet's disease, 23 patients with oral lichen planus, and 11 patients with burning mouth syndrome. The present study showed that there was an uneven distribution of oral surface pH. The palate had a higher pH than most other sites in all groups, and in patients with lichen planus, the palate pH was higher than that in healthy controls. Those with dentures had lower pH values in the hard palate than dentate patients. The relatively high pH in the palate region in all patient groups as well as healthy volunteers needs to be further studied to clarify its mechanisms and clinical relevance.

Adult↗
PubMedDate not supplied

Subcutaneous nodules attributed to nocardiosis in a renal transplant recipient on tacrolimus therapy.

We report a renal transplant patient who suffered from disseminated nocardiosis after empirical tacrolimus rescue therapy for chronic allograft rejection. The nocardiosis presented initially as only mildly tender subcutaneous calf nodules without any other signs of inflammation nor constitutional upset, which later spread to the lung and brain causing bronchopneumonia and brain abscesses. The risk factors for nocardial infection in our patient include the use of potent immunosuppressive agents such as tacrolimus, poorly controlled diabetes mellitus and kidney dysfunction. She responded well to combination antibiotic therapy comprising parenteral meropenem, cefotaxime and oral minocycline. We conclude that in transplant recipients, especially those receiving newer and more potent immunosuppressive agents like tacrolimus, nocardial infection can present as apparently 'cold' subcutaneous nodules without any systemic upset. An associated brain lesion should be excluded even in patients without neurological symptoms.

Anti-Bacterial Agents↗
PubMedDate not supplied

Cytomegalovirus-induced tubulointerstitial nephritis in a renal allograft treated by foscarnet therapy.

We report a female patient suffering from cytomegalovirus (CMV)-induced tubulointerstitial nephritis in a renal allograft 70 days after a cadaveric renal transplantation. CMV-induced renal allograft injury reported in the literature mainly related to immune-mediated mechanisms. In our patient, acute tubulointerstitial nephritis, associated with histological evidence of CMV infection, was demonstrated in the renal allograft biopsy. There were no histological features of allograft rejection, cyclosporin nephrotoxicity nor 'CMV glomerulopathy'. She was successfully treated by foscarnet therapy and a reduction in immunosuppression. Her renal function returned to baseline afterwards.

Adult↗