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Biomedical subjects

E C Tan

Publications and source records attributed to E C Tan.

At least 37 records · Page 2Linked to original sources
PubMed1993

Congenital inclusion cysts over the anterior fontanel in Japanese children: a study of five cases.

Congenital inclusion cysts over the anterior fontanel are rare in children in Asia and Europe. However, recent evidence of an increase in cases in both areas has been presented. In the period from 1980 to 1989, four patients with a dermoid cyst and one with an epidermoid cyst have undergone total excision in our department. Including the previously reported Japanese cases, the number of recorded Japanese cases is now 15, the number of Asian cases thus corresponding to the number in Europe. Although these lesions are unlikely to have intracranial extensions, noninvasive neuroimaging methods such as computed tomography and magnetic resonance imaging are recommended for preoperative investigations.

Child↗
PubMed1993

Re-evaluation of indications for percutaneous nephrostomy and interventional uroradiological procedures in pelvic malignancy.

Twenty-two patients with advanced cancer involving the pelvis were treated by percutaneous uroradiological techniques. Percutaneous nephrostomy was performed for renal failure or urosepsis or before chemotherapy. In 8 patients, ureteric stents were also placed by the antegrade route, across malignant ureteric strictures, following nephrostomy. In another 8 patients, the ureteric obstruction could not be crossed and permanent nephrostomies were required. Fifteen patients were able to achieve a useful life but in the other 7 patients there was no improvement in their quality of life and they all died 1 month after intervention. Percutaneous nephrostomy also contributed to the death of 1 patient. Not all obstructed kidneys require drainage and in patients with disseminated or advanced disease involving the pelvis, the indications for intervention need to be individually assessed. An improvement in laboratory criteria of renal function following intervention does not necessarily result in improvement in quality of life. This retrospective study highlights the difficulty in selection of patients with advanced disease for intervention and previously suggested guidelines for intervention are reviewed.

Catheterization↗
PubMed1993

Characteristics of histamine receptors in human cerebral arteries.

Histamine and 2,2-pyridylethylamine, an H1-receptor agonist, (both 10(-8)-10(-3) M) caused contraction of human cerebral artery preparations in the absence of active tension, while dimaprit, an H2-receptor agonist, caused vasorelaxation. The histamine-induced vasoconstriction was blocked non-competitively by tripelennamine, an H1-receptor antagonist. In the presence of cimetidine, an H2-receptor antagonist, histamine-induced contraction was enhanced. The histamine-induced contraction was not affected by phentolamine or propranolol, but abolished by nifedipine. In prostaglandin F2 alpha-precontracted arteries, histamine and dimaprit caused relaxation, while 2,2-pyridylethylamine had no apparent effect. Histamine-induced relaxation was much greater in the presence than in the absence of an H1-antagonist. The vasorelaxation induced by histamine in the presence of an H1-antagonist was also inhibited by an H2-antagonist. Histamine caused no apparent relaxation in precontracted preparations without endothelium. The present results provide further evidence that histamine causes either vasocontraction or vasodilation in human cerebral arteries, and suggest that vasocontraction and vasorelaxation are due to the activation of H1- and H2-receptors, respectively. The relaxation induced by histamine may also be related to the endothelium-derived relaxing factors released from endothelial cells.

Aged↗
PubMed1993

Acute obstructive hydrocephalus caused by a migrating intraventricular calculus. Case report.

A 10-year-old boy presented with acute obstructive hydrocephalus caused by the impaction of a calculus on the cerebral aqueduct. The calculus migrated from the third ventricle to the fourth ventricle after ventricular drainage and right ventriculoperitoneal shunt placement had been performed. The nature and origin of the calculus could not be determined, although its release from the choroid plexus in the lateral ventricle is highly possible.

Acute Disease↗
PubMed1993

[Regional phacomatosis with cerebral AVMs and cavernous hemangioma of the skull--report of a case].

We report the coexistence of multiple arteriovenous malformations (AVMs) and hemangioma of the skull in a 38-year-old man with associated varicose veins in his scalp. The patient also had hypotrophy of all right limb tissues with skin pigmentation and syndactyly of both feet. CT scans revealed intraventricular hemorrhage and a hemangioma of the skull at the posterior fossa. Because of the location of the arteriovenous malformations, surgical evacuation and resection were not attempted. The hemangioma was totally removed to decompress the posterior fossa. A few cases of regional phacomatosis with intracranial AVMs have been reported, but we could not find a report of the coexistence of intracranial multiple AVMs and hemangioma of the skull with associated varicose veins of the scalp and skeletal hypotrophy. We discuss on the etiology of the coexistence of regional phacomatosis and hemangioma and on the difference between our case and typical regional phacomatosis.

Adult↗
PubMed1992

Novel brain-specific bovine cDNA for a developmentally regulated mRNA encoding a putative new member of the leucine-rich glycoprotein (LRG) family.

We have isolated a bovine cDNA which hybridized to a 2 kb mRNA specifically expressed in the rat and human brain. The mRNA was abundantly expressed in adult but not 21-week old human brain. In the rat brain, there was very little of the transcript in 15-day old fetus but it increased in abundance with development, being most abundant in the adult and expressed in all brain regions. Genomic analysis showed that the sequence is single copy and conserved in all vertebrates examined, including chicken. The 702 bp partial cDNA encoded an amino acid sequence for a putative member of the leucine-rich glycoprotein (LRG) family known to be involved in cell adhesion/recognition. The predicted polypeptide displayed sequence identity with that recently reported for the human oligodendrocyte-myelin glycoprotein. This cDNA should prove useful in further investigations on brain-specific cell-cell interactions.

Amino Acid Sequence↗
PubMed1992

Does transurethral laser ureterolithotripsy justify its cost?

A prospective consecutive series of 64 patients who underwent transurethral laser ureterolithotripsy using a 7.2F semirigid ureteroscope was compared to the immediately preceding consecutive series of 98 patients who had undergone ultrasound lithotripsy using rigid 9.5F or 12.5F ureteroscopes. The distribution of the calculi by size and composition in both series was similar. There was a higher proportion of upper ureteral calculi in the laser lithotripsy series. The success rate for a first attempt at laser lithotripsy was 92.2% versus 71.4% for the ultrasound series (p less than 0.01). When the stone could be reached ultrasound and laser lithotripsy had a fragmentation rate of 97%. The principal reason for the difference in results was the poorer ability to reach calculi when using the larger rigid ureteroscopes. One patient who had failed ultrasound lithotripsy was successfully treated with laser lithotripsy a year later. The overall morbidity was less for laser lithotripsy. The 3-year cost-benefit analysis revealed a smaller difference in cost than expected and the 5-year analysis was advantageous for laser lithotripsy because of its higher success rate. Savings were also realized in the laser series because of the higher proportion of subjects treated as outpatients, and a lower mean duration of hospitalization and time missed from work. For our center with an annual work load of approximately 100 cases laser lithotripsy achieved a superior cost-benefit ratio.

Cost-Benefit Analysis↗
PubMed1991

Comparative studies of extracorporeal shock wave lithotripsy by Dornier HM3, EDAP LT 01 and Sonolith 2000 devices.

During a 2-year period extracorporeal shock wave lithotripsy (ESWL) was done at our institution in 70 patients with the Dornier HM3, 113 with the EDAP LT 01 and 104 with the Sonolith 2000 lithotriptors. The size and location of stones were comparable in all 3 series, and all treatments were done by the same team of urologists. Complete fragmentation occurred in 79% of the patients treated by the Dornier, 82% treated by the EDAP and 79% treated by the Sonolith devices, with 3-month stone-free rates of 66, 67 and 58%, respectively. Auxiliary procedures were needed in 12% of the patients in the Dornier, 13% in the EDAP and 9% in the Sonolith groups. Repeat treatment was necessary in 4% of the Dornier group, 42% of the EDAP group and 26% of the Sonolith group. Therefore, all 3 lithotriptors are effective in stone disintegration and produce satisfactory results when selection criteria for ESWL are observed. The most significant difference among the 3 lithotriptors is the number of repeat treatments, which reflects the power and energy output of the lithotriptors. In conclusion, the Dornier HM3 device has the advantage of low repeat treatment rate and easier stone localization. The EDAP LT 01 unit has the advantage of lower treatment costs and anesthesia-free treatment with no irradiation. The Sonolith 2000 device has features of the other 2 lithotriptors with a superior ultrasound image.

Anesthesia, Conduction↗
PubMed1991

Stones in horseshoe kidneys: results of treatment by extracorporeal shock wave lithotripsy and endourology.

We report the results of 7 patients with calculi in a horseshoe kidney treated by extracorporeal shock wave lithotripsy (ESWL, 9 renal units) and percutaneous nephrolithotripsy (3 renal units) during a 3-year period. In the ESWL only group complete stone clearance was achieved in only 3 patients (50%) after an average of 3 sessions of therapy. On the other hand, complete stone clearance was achieved by percutaneous nephrolithotripsy with minimal complications. The poorer results with ESWL were due to difficulty in ultrasonographic localization of stones as well as poor drainage in these abnormal kidneys. Our experience with the Edap LT01 and the Sonolith 2000 lithotriptors suggests that while reasonable results are possible, treatment probably will require multiple sessions and the eventual outcome is less predictable than in normal kidneys. In contrast, the treatment of complicated stones in a horseshoe kidney presents no additional difficulty.

Evaluation Studies as Topic↗
PubMed1991

Ring-enhanced primary intracranial malignant lymphoma--report of two cases.

Two nonimmunosuppressed patients with primary intracranial malignant lymphoma demonstrated ring-enhanced lesion on postcontrast CT scans. One patient underwent total removal of the tumor and the other patient biopsy, both followed by whole brain irradiation. Histological examination revealed the tumors contained diffuse large cells and necrosis in the central region. The possible mechanisms of ring enhancement may represent central necrosis of the rapidly growing tumor, but is probably not related to the prognosis.

Aged↗
PubMed1991

Malignant fibrous histiocytoma of the occipital bone with intracranial extension--case report.

The authors present a rare case of malignant fibrous histiocytoma originating in the cranial bone. A 72-year-old male was admitted with a diffuse painless swelling in the left occipital region but no neurological abnormality. Plain skull x-ray films and computed tomographic scans showed a large tumor in the left temporo-occipital bone. The tumor invading subcutaneous tissue was totally excised and histologically diagnosed as malignant fibrous histiocytoma. Postoperatively, 40-Gy irradiation was given to the left temporo-occipital region. Several months later, however, the tumor recurred in the posterior fossa. Neuroradiological examination showed tumor extension into the occipital bone and muscle and the subdural space of the posterior fossa. A second operation extirpated all tumors except in the cerebellum. He died of pneumonia on the 14th postoperative day. Autopsy revealed malignant fibrous histiocytoma invading into the bilateral cerebellar hemispheres. Radiation and chemotherapy should be given as soon as possible following extensive surgery for malignant fibrous histiocytoma of the cranial bone.

Aged↗
PubMed1991

Intracranial carotid artery occlusion with telangiectasia (moyamoya disease) associated with persistent primitive trigeminal artery--case report.

A 35-year-old female presented with moyamoya disease coincidentally associated with a persistent primitive trigeminal artery (PPTA). Bilateral encephalo-duro-arterio-synangiosis was performed and the postoperative course was uneventful. Moyamoya disease and PPTA might have a congenital origin, but moyamoya disease may be promoted by a PPTA. The hemodynamics of PPTA during progressive occlusive change in the internal carotid artery in moyamoya disease should be re-evaluated to determine its function in the development of moyamoya vessels.

Adult↗
PubMed1991

Intravesical chemotherapy for superficial carcinoma of the bladder.

Intravesical chemotherapy has been shown to be of value in the treatment of superficial transitional cell carcinoma of the bladder, not only in the prevention of recurrence but possibly progression of the disease to higher stage as well. At the Department of Surgery, National University of Singapore from 1980 to 1986 we had used intravesical chemotherapy for multiple or recurrent superficial carcinoma of bladder in 45 patients. Of these, 21 patients had associated carcinoma in situ. Initially, thiotepa was used as the main intravesical chemotherapeutic agent. Since 1984, mitomycin C was introduced. The schedule used is 30 mg in 30 mg of water, and left in the bladder for 2 hours weekly for 4 weeks. Intermittent courses were given when deemed necessary on follow-up cystoscopy at 3 to 6 months. Patients were deemed to have good response if there was no evidence of tumour on cytology and biopsy at follow-up cystoscopy. Eleven patients had thiotepa only, of these 4 had good response, 4 were stable and 3 had progression of disease to higher stage. Thirty-four patients had mitomycin therapy. Thirteen of them following thiotepa treatment. Twenty-one patients (64%) had good response to therapy. Three patients (9%) had progression of disease, requiring cystectomy. Of those who responded to therapy, none had developed muscle invasive disease so far with mean follow-up of 43 months. Of the group of patients treated with mitomycin, no patient developed myelosuppression.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravesical↗
PubMed1991

Organ procurement in Singapore.

Kidney transplantation, an accepted therapeutic intervention for patients with end stage kidney failure, was pioneered in Singapore on 8 July 1970 by the University Departments of Surgery and Medicine, University of Singapore. Up to 1987, an average of 4.7 cadaveric kidney transplants were performed annually. The introduction of Sandimmune (cyclosporine) in 1985 significantly increased graft survival and consequently created a demand for more cadaveric kidneys for transplantation. The rate of cadaveric kidney transplants escalated to 31.3 kidney transplants annually for the period 1988 to 1990. This increase can be attributed both to the appointment of full time transplant coordinators beginning April 1986 and the implementation of the Human Organ Transplant Act in July 1987. The Human Organ Transplant Act accounted for more than half of all kidneys procured for transplantation (55/94) for the period 1988 to 1990.

Cadaver↗
PubMed1991

Techniques of ureteric reimplantation in kidney transplantation and its related urological complications.

Two common techniques of ureteric reimplantation for kidney transplantation, the Politano-Leadbetter and the extravesical ureteroneocystostomy are described in detail. Correct techniques of donor ureter harvesting, appropriate method of reimplantation and judicious use of double J stent are also emphasised so as to reduce the urological complications which occurred in about 7% to 15% in most series. More than 90% of urological complications are due to urinary fistulae and ureteric obstruction which carry a significant morbidity and mortality. The causation, diagnosis and management of these complications are reviewed. Early diagnosis and early aggressive surgical treatment is the key to a successful outcome.

Cystostomy↗