Biomedical subjects

A Chee

Publications and source records attributed to A Chee.

5 recordsLinked to original sources

PubMed2000

Alpha 4 integrin-dependent leukocyte recruitment does not require VCAM-1 in a chronic model of inflammation.

Rats immunized with Mycobacterium butyricum in Freund's adjuvant develop a chronic vasculitis, with large increases in leukocyte rolling and adhesion in mesenteric postcapillary venules that are significantly inhibited with an alpha 4 integrin Ab. Using intravital microscopy to visualize chronically inflamed microvessels, we demonstrated that alpha 4 integrin-dependent leukocyte rolling and adhesion was inhibited with a beta 1 integrin, but not a beta 7 integrin Ab. To date, VCAM-1 has been presumed to be the primary ligand for alpha 4 beta 1 integrin in the vasculature. However, alpha 4 beta 1 integrin-dependent interactions were not reduced by monoclonal or polyclonal VCAM-1 Abs or a VCAM-1 antisense oligonucleotide despite increased VCAM-1 expression in the mesenteric vasculature. To ensure that the VCAM-1 Abs were functional and used at saturating concentrations, blood from Ab-treated rats was perfused over monolayers of CHO cells transfected with rat VCAM-1. Sufficient alpha 4 integrin or VCAM-1 Ab was present to inhibit leukocyte interactions with rat VCAM-1 by 95-100%. Under in vitro flow conditions, only mononuclear leukocytes were recruited from blood of control rats onto purified VCAM-1. However, neutrophils were also recruited onto VCAM-1 from whole blood of adjuvant-immunized animals via alpha 4 integrin. Another ligand for alpha 4 beta 1 integrin is the connecting segment-1 (CS-1) region of fibronectin. An Ab to the CS-1 portion of fibronectin, which did not reduce rolling and adhesion in adjuvant arthritis animals, completely inhibited leukocyte adhesion to CS-1 under static conditions. These findings provide the first evidence that alpha 4 beta 1 integrin-dependent leukocyte rolling and adhesion can occur in vivo via a mechanism other than VCAM-1.

Adjuvants, Immunologic↗

PubMed1997

Transcutaneous carbon dioxide measurement after craniotomy in spontaneously breathing patients.

OBJECTIVE: The purpose of this study was to determine the incidence of postoperative hypercarbia in patients undergoing intracranial neurosurgery. Postoperative hypercarbia is a well-recognized cause of postoperative morbidity. METHODS: Sixty-four patients undergoing craniotomy were monitored in the first 36 postoperative hours using transcutaneous CO2 monitoring. We collected and analyzed demographic data, complete medical histories and examinations, and details of surgery, anesthesia, and postoperative progress. The accuracy of the transcutaneous CO2 monitoring was evaluated by comparison with arterial blood gas CO2. INSTRUMENTATION: The "TINA" TCM3 Transcutaneous CO2 Monitor (Radiometer, Copenhagen, Denmark) was used. RESULTS: Thirty-nine patients (61%) developed no hypercarbia. Nineteen patients (30%) developed mild to moderate hypercarbia (46-59 mm Hg) and six patients (9%) developed severe hypercarbia (60 mm Hg or greater). Statistically significant differences were observed between the severely hypercarbic group and the other two groups combined, as follows: a higher incidence of preoperative and postoperative seizures, a lower average postoperative Glasgow Coma Scale score, a higher incidence of reintubation and ventilation, and a higher degree of intraoperative brain disturbance. Analysis of transcutaneous CO2 measurements and time-matched arterial blood gas CO2 measurements revealed an acceptable accuracy of the transcutaneous method. CONCLUSION: this study demonstrates that, in routine neurosurgical practice, a subgroup of patients are at risk of developing postoperative hypercarbia, which may be more common than is generally recognized and will not usually be detected by routine postoperative monitoring. Transcutaneous CO2 monitoring is a useful technique that may impact management decisions.

Adolescent↗

PubMed1996

Working Party report of the Gastroenterological Society of Singapore. Part I--Helicobacter pylori and peptic ulcer disease in Singapore.

The Gastroenterological Society Working Party on Helicobacter pylori (H pylori) recommends eradication of H pylori in patients with peptic ulcer, provided H pylori infection has been demonstrated. H pylori treatment is not indicated for non-ulcer dyspepsia, histological gastritis or mere demonstration of H pylori infection. H pylori infection can be demonstrated by a urease test, culture or histological assessment on gastric antral biopsy or by a 13C and 14C urea breath test: serology is acceptable if validated in the local population. There are many eradication regimens for H pylori infection and follow-up assessments to demonstrate eradication is desirable.

Gastroenterology↗

PubMed1996

Working party report of the Gastroenterological Society of Singapore. Part II--Helicobacter pylori and non-ulcer dyspepsia in Singapore.

Non-ulcer dyspepsia (NUD) is a common symptom whose cause is currently unclear. Helicobacter pylori (H pylori) infection is found in half of all patients with NUD but other pathophysiological abnormalities eg delayed gastric emptying, have also been described. NUD patients with or without H pylori infection have identical symptom patterns and pathophysiological parameters. Studies on the efficacy of H pylori treatment in NUD give equivocal results to date. We therefore do not recommend treatment for H pylori in NUD.

Developing Countries↗

PubMed1987

Abdominal tuberculosis revisited.

Four patients with abdominal tuberculosis (ATB) managed in the University Department of Medicine, Singapore General Hospital, are presented to highlight problems encountered in the diagnosis of this condition. Three patients had intestinal tuberculosis, one of whom had peritoneal involvement and another had possible hepatic disease. The fourth patient presented with peritoneal disease alone. Ages at presentation ranged from 25 years to 71 years. There were three females and one male. Two patients presented with symptoms of chronic illness for 10 months before the disease was diagnosed. Two other patients had acute presentations. Fever, abdominal pain, vomiting and diarrhoea were the main symptoms encountered. Three patients had abdominal masses at diagnosis. Radiological investigations were the most useful diagnostic aid. Bacteriological confirmation was made in only one patient. Histology helped in the diagnosis in two others. Recent literature on this condition was reviewed and the possible role of impaired immunity in the pathogenesis of this condition was discussed.

Adult↗