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Biomedical subjects

W S Tan

Publications and source records attributed to W S Tan.

At least 55 records · Page 3Linked to original sources

Partial splenic embolization, an alternative to splenectomy--results of a prospective, randomized study.

UNLABELLED: We conducted a prospective, randomized study comparing transcatheter partial splenic embolization (PSE) with splenectomy (SX) in 53 renal transplant candidates. An additional 112 PSE procedures were performed for various indications in 101 patients. STUDY RESULTS: A mean +/- SD of 65% +/- 16% of splenic mass was ablated in the PSE group. The early postoperative morbidity rate was similar in the two study groups, as was the duration of hospital stay. Abscess or rupture of the spleen were not encountered. Severe pancreatitis occurred only in the SX group. Renal transplantation was carried out in equivalent numbers in both groups, with a similar long-term (2.5 to 4.0 years) graft survival (60% versus 66%). No difference in long-term patient mortality was noted. Splenic "regeneration" occurred frequently after PSE. PSE experience exclusive of study: Embolization attempts failed in nine patients. Repeat PSE was performed in 11 of the 101 patients. Where hypersplenism was the primary indication, PSE resulted in significant improvement in the hematologic parameters. The incidence of serious complications was acceptably low. There were two late procedure-related deaths. Our conclusion from the study and the total experience of 137 PSE procedures is that PSE offers an acceptably safe alternative to SX in selected high-risk patients in whom both the surgical intervention and the resulting asplenic state carry a prohibitive risk.

Adolescent↗

A new method for radiolabeling of Gelfoam particles with 99mTc.

Embolization of the spleen and other organs using Gelfoam has recently gained acceptance as a therapeutic procedure. A simple non-invasive determination of the placement of Gelfoam particles is needed and this requires labeling Gelfoam with radionuclides. We have developed a simple, reliable reproducible, and inexpensive method of labeling Gelfoam with 99mTc using commercial sulfur colloid kits. Optimal reaction conditions include room temperature incubation for 60 min at 12 rpm rotation. In vitro stability indicated no loss of 99mTc activity up to 3 h post labeling. Imaging of intra-arterially placed 99mTc Gelfoam at 1 h and 24 h in animals and humans has consistently produced well-defined images of the radioemboli.

Animals↗

Partial splenic embolization in the management of thalassemia major.

Six patients with beta-thalassemia major underwent partial splenic embolization as an alternative to splenectomy. One patient required 2 embolizations. All 6 patients showed a marked reduction in transfusion requirements. Transfusion requirements fell to a level within that reported by other authors following total splenectomy, although significantly above that of a group of patients from the same institution who underwent total splenectomy. It is felt that this procedure provides an acceptable alternative to splenectomy in these patients with the possible preservation of some splenic immune function.

Adolescent↗

Splenic embolization.

While transcatheter embolization of the spleen has shown promise in the treatment of a wide spectrum of disorders, the incidence of serious complications with this technique has limited its use as an alternative to operative splenectomy. In our institution 41 patients were treated with a modified technique involving partial splenic embolization, careful antibiotic prophylaxis, and adequate pain control. There was no mortality and only few instances of clinically significant complications: a splenic abscess in one patient, pancreatitis in one patient, severe pleural effusions in two patients, and pneumonia in five patients.

Adolescent↗

MRI in intraventricular neurocysticercosis: a case report.

A young Mexican female developed neurocysticercosis presenting as a lymphocytic meningoencephalitis with eosinophilia. Parasitic cysts in the fourth ventricle and pre-pontine cistern were well visualized by magnetic resonance imaging but not by computerized tomography. The meningoencephalitis recurred despite treatment with praziquantel and dexamethasone, and obstructive hydrocephalus eventually developed. The patient remains well one year after excision of the intraventricular cyst. This case emphasizes the distinct advantages of magnetic resonance imaging in the diagnosis of intraventricular neurocysticercosis, and the potential need for surgical rather than medical intervention in this condition.

Adult↗

Postmyelographic CT evaluation of multiple blocks due to metastases.

A case of intraspinal metastatic carcinoma that presented on combined cervical and lumbar puncture metrizamide myelography as complete blocks at T2 and T12 is described. The extent of disease in the long segment of the spinal canal was inaccessible to conventional myelography. This case illustrates the importance of postmyelogram CT for accurate assessment of disease and for treatment planning.

Humans↗

Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing systems.

This study investigated the surface texture of two resin-modified glass ionomer cements (RMGICs) in the vertical and horizontal axis after treatment with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-flute tungsten carbide burs. The teeth were then randomly divided into four groups and finished/polished with (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Points (CS). The sample size for each material-finishing/polishing system combination was eight. The mean surface roughness (microm) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Mean RaV ranged from 0.59-1.31 and 0.83-1.52, while mean RaH ranged from 0.80-1.43 and 0.85-1.58 for Fuji II LC and Photac-Fil, respectively. Results of statistical analysis were as follows: Fuji II LC: RaV-RC, SS<OG & SS<CS; RaH-SS, CS<RC, OG; Photac-Fil: RaV- SS, CS<OG; RaH-SS<RC, OG & CS<RC (where < indicates significantly greater Ra values). Significant differences in RaV and RaH values were observed when Fuji II LC was finished with RC. The use of carbides (RC) and one-step rubber abrasive system (OG) for finishing/polishing of RMGICs is not recommended. Graded abrasive disk (SS) or two-step rubber abrasive (CS) systems should be used instead.

Analysis of Variance↗

Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing time.

This study compared the surface texture of resin-modified glass ionomer cements after immediate and delayed finishing with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of 64 freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (3M-ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-fluted tungsten carbide burs. The teeth were then randomly divided into four groups of 16 teeth. Half of the teeth in each group were finished immediately, while the remaining half were finished after one-week storage in distilled water at 37 degrees C. The following finishing/polishing systems were employed: (a) Robot Carbides; (b) Super-Snap system; (c) OneGloss and (d) CompoSite Polishers. The mean surface roughness (microm; n=8) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Ra values were generally lower in both vertical and horizontal axis with delayed finishing/polishing. Although significant differences in RaV and RaH values were observed among several systems with immediate finishing/polishing, only one (Fuji II LC: RaH - Super-Snap < Robot Carbides) was observed with delayed finishing.

Analysis of Variance↗