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Biomedical subjects

A C Tan

Publications and source records attributed to A C Tan.

At least 19 recordsLinked to original sources
PubMed2001

[Patient with refractory celiac disease and secondary lymphoma].

A 50-year-old woman who had suffered from well-regulated coeliac disease for 16 years, presented with weight loss, soft stools and abdominal cramps. She had ulcers in the oesophagus and stomach, and in biopsies localisations of so-called enteropathy-associated T-cell lymphoma (EATL) were detected. During a staging investigation she suffered an enteric perforation and later on repeated haemorrhages, from which she eventually died. Patients with coeliac disease who do not respond to a gluten free diet or who relapse after an initial response should be investigated for the presence of a gastrointestinal malignancy. Weight loss is an important symptom. The most frequently occurring malignant complication is an EATL. This is often difficult to diagnose and the prognosis is poor, with frequent complications such as haemorrhages and perforations.

Biopsy↗
PubMed2001

[Hypercalcemia due to adult T-cell lymphoma in a man from Surinam].

A 48-year-old male patient from Surinam presented with anorexia, nausea and weight loss. An extreme hypercalcaemia of 5.08 mmol/l was found. Further diagnostic investigations showed that this patient had a HTLV-1 positive adult T-cell leukaemia/lymphoma (ATL/L). This is often associated with multilobularly nucleated lymphocytes, bone destruction and hypercalcaemia. Skin localisations are frequently observed. The combination of cytomorphology, immunophenotyping, HTLV-1 seropositivity and clinical findings points to the diagnosis. The patient was treated with 6 courses of chemotherapy consisting of cyclophosphamide, doxorubicin, teniposide, prednisone, vincristine and bleomycin. Upon inquiry it appeared that he had died elsewhere. Chemotherapy induces a short-lived remission in a minority of ATL/L patients. Antiviral therapy (alpha interferon, zidovudine) might offer new possibilities.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Eosinophilic gastroenteritis treated with non-enteric-coated budesonide tablets.

A patient who presented with upper abdominal pain, nausea and ascites together with peripheral eosinophilia is described. Based on a surgical full-thickness biopsy of the antrum, the diagnosis of eosinophilic gastroenteritis was made. Treatment with prednisone resulted in a clinical response, but the prednisone dose could not be lowered below 5 mg. We preferred to treat the patient with corticosteroids with minimal systemic side effects. As there was gastric involvement, we could not give enteric-coated budesonide capsules. Therefore, we treated the patient with budesonide tablets, which were designed originally for use as a clysma but now are given orally. With this treatment regimen, the patient has been in remission for more than 2 years.

Adult↗
PubMed2000

Uterine hemorrhage in a menopausal female associated with an arteriovenous malformation and myometritis.

A case is described of vaginal bleeding in a 67-year-old female as the first manifestation of a uterine arteriovenous malformation (AVM). Although bleeding is the commonest presentation of an AVM, this is the first case known to have been precipitated by florid myometritis associated with the long-standing presence of an intra-uterine contraceptive device (IUCD). Uterine imaging studies utilising ultrasound scan with color Doppler were instrumental in suggesting the source of bleeding in this case. Subsequently, the patient suffered a torrential hemorrhage which necessitated hysterectomy.

Aged↗
PubMed2000

Implementation of a dedicated optical fibre network for real time stereo imaging.

This paper describes the successful implementation of a dedicated fibre optic network for the real time stereo video imaging. It shows the approach in the design of both configuration and signalling requirements. It overcomes problems associated with standard optical network components and budget constraints of using specialised designs. The flexible configuration, using patch panels, allows for endless scenarios of routing the various audio, video and computer equipment signals to multiple locations. This arrangement permits dedicated point to point link or multicasting to two locations simultaneously. Redundancies in the fibre allocation enable fail safe operations and future expansion capabilities for other medical and IT applications.

Computer Communication Networks↗
PubMed2000

Abdominal pregnancy: a case report and literature review.

We report a rare and unusual case of an Abdominal pregnancy that was delivered successfully at term. It is the first documented case in the local literature in almost 30 years. What makes it even more exceptional is that despite the high mortality associated with the condition, both mother and baby survived the ordeal. She subsequently delivered another child, 2 years later by an elective lower segment caesarean section and had a tubal ligation performed concomitantly. A review of the topic and its management is also presented.

Adult↗
PubMed1999

Eradication of Helicobacter pylori does not decrease the long-term use of acid-suppressive medication.

BACKGROUND: Many patients are not symptom-free after eradication therapy for Helicobacter pylori and continue to use proton pump inhibitors or H2-receptor antagonists (H2-RAs). AIM: To ascertain whether a cohort of patients treated for H. pylori were still taking either proton pump inhibitors or H2-RAs more than 4 years after H. pylori eradication therapy. METHODS: In 1993-94, a cohort of 167 patients were given eradication therapy for their H. pylori infection. By means of questionnaires to the patient, general practitioner and pharmacist we were able to retrieve data from 151 patients. The use (at the time of questionnaire) of proton pump inhibitors or H2-RAs was noted. RESULTS: Indications for eradication therapy were peptic ulcer disease: 28 patients (19%) or functional dyspepsia: 123 patients (82%). Mean time of follow-up was 1466 +/- 21 days. In this group, 77 patients (51%) still used acid-suppressive medication (proton pump inhibitors 44% and H2-RAs 7%) at the time of the survey (mean follow-up more than 4 years after eradication). In the group treated for peptic ulcer disease (n=28), only nine patients still used proton pump inhibitors or H2-RAs. In contrast, 68 patients who were treated for functional dyspepsia (total number 123) still used proton pump inhibitors or H2-RAs (55%) (P < 0.05). CONCLUSION: Even after successful H. pylori eradication, < 50% of patients stop acid-suppressive therapy. This contributes significantly to economic cost and raises doubts about the practice of routinely eradicating H. pylori in patients with functional dyspepsia. In contrast, the majority of peptic ulcer patients are able to stop acid-suppressive medication.

Adult↗
PubMed1999

Increased survival in advanced primary biliary cirrhosis patients with regular albumin infusions?

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease. Frequently, it can slowly progress to cirrhosis and, finally, death. Liver transplantation is the only way to avoid this endpoint. For patients not accepted for liver transplantation, only symptomatic treatment remains. In advanced PBC, one of the main concerns is a decreasing albumin level. As albumin is an important protein in the human body, we wondered whether regular albumin infusions may result in a higher quality of life and prolong survival. In this case report we describe three patients who survived for a remarkably long time on this treatment regimen before finally succumbing to the sequela of advanced liver disease. Some features of albumin are mentioned which may help explain this phenomenon. We conclude that regular albumin infusions may be a means of decreasing morbidity and prolonging survival in a subgroup of patients with advanced PBC. However, prospective evaluation of regular albumin infusions in a group of PBC patients (e.g. those rejected for liver transplantation) seems mandatory.

Aged↗
PubMed1997

[Chronic hepatitis C in hemodialysis patients].

Hepatitis C virus (HCV) is an important cause of chronic hepatitis in dialysis patients. With regard to epidemiology, the time on haemodialysis, the (previous) use of intravenous drugs as well as the number of blood transfusions received are important risk factors. There are strong indications suggesting nosocomial transmission of HCV. Strict application of infection prevention procedures in haemodialysis units is mandatory to restrain spread of HCV infection. Preliminary results show equal efficacy of alpha-interferon in normalisation of serum transaminases in dialysis patients and in patients with normal kidney function. However, in both groups relapses occur often, despite induction of remission. Antiviral therapy (with interferon and ribavirin) is emerging as a valid option to induce HCV eradication in dialysis patients. Thereafter, transplantation may be considered.

Antiviral Agents↗
PubMed1997

No additional value of bismuth subcitrate to combination omeprazole/amoxicillin therapy in the eradication of Helicobacter pylori.

BACKGROUND: We investigated whether addition of bismuth subcitrate (BSC, 4 x 120 mg) to a two week therapy scheme of omeprazole (OME, 2 x 40 mg)/amoxicillin (AMO, 4 x 500 mg) increases Helicobacter pylori eradication. MATERIALS AND METHODS: Patients with dyspepsia underwent upper endoscopy. H. pylori positive patients were randomized to treatment A (OME/AMO, 83 patients) or treatment B (OME/AMO/BSC, 84 patients). RESULTS: In 65 patients of group A (78%) H. pylori was eradicated as determined from the histological assessment (Sydney classification) of antrum and corpus biopsies. In comparison, in 68 patients of group B (81%) H. pylori was eradicated (p = NS between groups). H. pylori eradication in both groups was associated similarly with a decrease of inflammation and activity whereas atrophy and intestinal metaplasia were not affected. A positive association was revealed between the decrease of H. pylori score and the decrease of both inflammation and activity scores for antrum as well as corpus biopsies. CONCLUSIONS: Addition of BSC to OME/AMO does not increase H. pylori eradication in patients with dyspepsia. Eradication of H. pylori is associated with disappearance of epithelial damage (inflammation and activity) in antral and corpus mucosa.

Adult↗
PubMed1997

Tele-education: the virtual medical laboratory.

The virtual medical laboratory (VML) was conceived to provide an Internet-accessible resource, offering access for clinicians and scientists to an invaluable data archive at the institute of Laryngology and Otology, London. The Institute is home to the largest collection of temporal bone, laryngeal, skull and sinus sections in Europe. The skull and sinus collections include an extensive section consisting of animal material. These were contributions from zoos around the world. Over the last 50 years, samples have been carefully sectioned and stained by specialized technicians to produce histology slices of most regions of the head and neck. The aim of the project is to create a virtual medical laboratory, which will provide access to archived histological material as well as computerized tomography and magnetic resonance data. Central to this aim is the reconstruction of the internal anatomy of the temporal bone from two-dimensional histology slices, to create three-dimensional views that can be used for anatomical simulation and surgical training in otolaryngology. State-of-the-art three-dimensional reconstruction and rendering technology allows us to develop such a model. Computer-generated simulation could be made available to all hospitals in which otolaryngology is practised, via digital communication networks. We aim to develop core technology in our own specialty that is applicable to other fields of higher education, which have not been exposed to such modern teaching modalities. This has the potential to become an invaluable teaching resource for anatomists, surgeons and other scientists.

Computer Communication Networks↗
PubMed1997

Cervicovaginal foetal fibronectin in the prediction of preterm labour in a low-risk population.

The aim of this study was to evaluate the role of cervicovaginal fibronectin as a screening test in a low-risk population. Swabs were taken from the posterior fornix at 28 weeks gestation and foetal fibronectin levels were assayed using enzyme immunoassay. Eighteen patients (7.7%) delivered at less than 37 weeks of gestation, and 6 (2.4%) at less than 34 weeks of gestation. Five patients (2.1%) had a positive fibronectin test result. The sensitivity, specificity, positive predictive value and negative predictive value in the prediction of delivery less than 37 weeks of gestation were 16.7%, 99.1%, 60.0% and 93.4%, respectively. The sensitivity of foetal fibronectin in the prediction of delivery less than 34 weeks of gestation was higher (50%) compared with the prediction of delivery less than 37 weeks of gestation (16.7%). The low sensitivity of this test suggests a limited role for cervicovaginal fibronectin in the low-risk population. Further studies need to be carried out to assess whether multiple testing of cervicovaginal fibronectin at different gestational ages will further increase the sensitivity.

Cervix Uteri↗
PubMed1994

Three-dimensional computed tomography cholangiography: a new technique for biliary tract imaging.

Knowledge of the segmental anatomy and intersegmental biliary connections is an essential prerequisite to the effective management of patients with complex biliary strictures. Three dimensional (3D) imaging has the ability to demonstrate complex anatomical relationships that are difficult to appreciate on simple non-invasive two dimensional (2D) imaging. Our aim was to develop a technique for accurate, non-invasive 3D computed tomography (CT) cholangiography. Contiguous 4 mm CT sections were obtained through the liver during a dynamic bolus of 200 ml IV contrast. 3D surface reconstructions were then performed, the biliary system was isolated from surrounding hepatic parenchyma using segmentation and contrast threshold algorithms. 14 patients (six females, eight males, median age 68 years (range 48-82)) were studied. 13/14 had malignant biliary obstruction and one had obstruction secondary to a pancreatic pseudocyst. Obstruction was at the liver hilum in eight, the common bile duct in five and the common hepatic duct in one. Four patients had biliary endoprostheses but were symptomatic from inadequate drainage. There was good demonstration of the biliary anatomy, obstructed segments and intersegmental biliary connections in 13/14; irregular biliary dilatation secondary to primary sclerosing cholangitis rendered interpretation difficult in one. 3D cholangiography provided a useful adjunct to other imaging techniques. In particular, in patients with complex hilar strictures it aided implementation of appropriate interventional drainage procedures.

Aged↗
PubMed1993

Comparison of cyclic guanosine monophosphate response to infusion of atrial natriuretic peptide in young and elderly subjects.

OBJECTIVE: To compare the sensitivity to atrial natriuretic peptide (ANP) in young and elderly subjects. DESIGN: Double-blind, random-order, placebo-controlled study using two different rates of ANP infusion. SUBJECTS: Eight healthy young (23 +/- 3 years, mean +/- SD) and eight healthy elderly (76 +/- 4 years) subjects recruited from the general population. MEASUREMENT: Plasma cyclic guanosine monophosphate (cGMP, the second messenger of ANP) levels reflecting the sensitivity of biologically active ANP receptors. RESULTS: Baseline ANP levels were higher and rose to a greater extent in the elderly both during low- (0.25 microgram/min) and high-dose (2.0 micrograms/min) infusion of ANP. Plasma levels of cGMP rose in proportion to the increase in ANP. When the rise in cGMP levels was related to the increase in ANP levels (expressed as nmol/L per 100 pg/mL ANP increase), no difference was found between young and elderly subjects. CONCLUSION: The ability of elderly subjects to increase cGMP in response to exogenous ANP is similar to that of young subjects. This may reflect a similar sensitivity of the target organs towards ANP. However, because of lower clearance in the elderly, a similar dose of ANP results in a greater elevation of ANP and cGMP levels and hence induces a greater effect.

Adult↗