Irukandji-like syndrome in Victoria.
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Adult↗
Biomedical subjects
A C Cheng
Publications and source records attributed to A C Cheng.
Using a facsimile (fax) as an aid for communication in maxillectomy planning between the prosthodontist and surgeon.
Preoperative communication between the prosthodontist and surgeon is required for properly planning the surgical prostheses that are often indicated for maxillectomy patients. When geography or long distances preclude face-to-face consultation, electronic means of correspondence are necessary to minimize delays in the fabrication of surgical prostheses. This article presents a time-efficient procedure for facilitation of the necessary communication between the prosthodontist and surgeon before maxillectomy surgical procedures.
Communication↗
Intraorbital needle fragment: a rare complication of retrobulbar injection.
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Aged↗
A review of glass ionomer restorations in the primary dentition.
Glass ionomer cements are tooth-coloured materials that bond chemically to dental hard tissues and release fluoride for a relatively long period. They have therefore been suggested as the materials of choice for the restoration of carious primary teeth. However, the clinical performance of conventional and metal-reinforced glass ionomer restorations in primary molars is disappointing. And although the handling and physical properties of the resin-modified materials are better than their predecessors, more clinical studies are required to confirm their efficacy in the restoration of primary molars.
Child↗
Reconstruction of cranial bone defects using alloplastic implants produced from a stereolithographically-generated cranial model.
Larger cranial bone defects can cause cranial disfigurement as well as potential mechanical brain trauma. Conventionally pre-fabricated acrylic cranioplasty implants require complicated procedures and result in potential dimensional and contour inaccuracies. The development of stereolithographic techniques for generating acrylic resin skull models allows the pre-fabrication of custom acrylic resin cranial implants with greater clinical predictability.
Craniocerebral Trauma↗
Vacuum-formed matrix as a guide for the fabrication of craniofacial implant tissue bar-retained auricular prostheses.
Craniofacial implant-retained auricular prostheses usually require a tissue bar and/or retentive elements in addition to the prosthetic ear. Complete coverage of the tissue bar and retentive elements in a given bulk of prosthetic material is sometimes difficult to achieve, but it is crucial to ensure that all the prosthetic components are kept within the contour of the auricular prosthesis to maintain esthetics and form. This article describes a method for fabrication of auricular prostheses with all the elements predictably confined within the anatomic contour of the prostheses.
Ear, External↗
1997 Judson C. Hickey Scientific Writing Awards. Lip prosthesis retained with resin-bonded retentive elements as an option for the restoration of labial defects: a clinical report.
Surgical resection of the lips is a relatively uncommon procedure, and it usually presents surgical and prosthodontic rehabilitation challenges. The goals of prosthetic treatment include regaining favorable speech and restoration of esthetics. This clinical report described a method for fabricating a lip prosthesis that uses resin-bonded retentive elements bonded to the patient's teeth for retention. Clinical and laboratory procedures of the prosthetic treatment were described, and the advantages and disadvantages were reviewed.
Acrylic Resins↗
The management of implant-retained overdenture treatment with custom-made metallic attachment housing.
A technique using a custom-made cast alloy attachment housing for an implant-retained overdenture prosthesis is presented. Common problems encountered in implant-tissue bar-retained overdentures are discussed. Details of the modified laboratory procedure are described. This technique provides the clinician with an alternative for predictably treating patients with implant-retained overdentures.
Acrylic Resins↗
Wide margin resection and brachytherapy for post-irradiation breast cancer recurrence.
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Brachytherapy↗
Immediate maxillofacial prosthodontic rehabilitation after radical mid-face tumor resection.
Mid-facial surgical defects can adversely affect a patient's esthetics and psychological well-being. Fabrication of a definitive mid-facial prosthesis can be a time-consuming procedure. It is crucial to minimize the time between the tumor resection and initial prosthetic rehabilitation. This article describes a method for rapid fabrication of a transitional facial prosthesis for mid-facial defects.
Aged↗
Head positioning and projection errors in submentovertex radiographic analysis.
This study examined the changes seen on the submentovertex radiograph when the head is not extended sufficiently. A human dry skull supported on a cephalostat was used to simulate head extension. The range of rotation tested was an under-rotation of the skull of 30 degrees to an over-rotation of 10 degrees in intervals of 5 degrees. The measured variables were the intercondylar axis angles, corpus lengths and condylar widths. The relationships between skull rotation and changes in these variables were determined. Three selected landmarks, the spinosa points (right and left) and the pogonion point of each radiograph were located and compared spatially with the same points on the ideal radiograph. The results showed that variation in skull rotation affects both linear and angular measurements significantly (P < 0.01). Landmarks further away from the axis of rotation are affected by distortion more than those nearer to it.
Cephalometry↗
The antiemetic efficacy of tropisetron plus dexamethasone as compared with conventional metoclopramide-dexamethasone combination in Orientals receiving cisplatin chemotherapy: a randomized crossover trial.
1. We report a single-blind randomized crossover trial comparing the efficacy of tropisetron plus dexamethasone (TROPDEX) vs conventional combination of metoclopramide, dexamethasone and diphenhydramine (METDEX) in prevention of acute and delayed vomiting in Chinese patients receiving high dose cisplatin. 2. Thirty-six consecutive patients with nasopharyngeal carcinoma were entered into the study, all received cisplatin at a dose range of 60-100 mg/m2. Patients were randomized in the sequence of antiemetic regimens used in two consecutive cycles. 3. The TROPDEX regimen consisting of tropisetron 5 mg i.v. and dexamethasone 20 mg i.v. given on day 1 of chemotherapy, followed by oral maintenance with tropisetron 5 mg daily and dexamethasone 4 mg twice daily from day 2 to 6. The METDEX regimen consisting of metoclopramide 1 mg kg-1 i.v., dexamethasone 20 mg i.v. and diphenhydramine 25 mg i.v. given before chemotherapy and then 2 hourly for two more doses on day 1, followed by oral metoclopramide 20 mg 6 hourly from day 2 to 6. 4. Complete control of acute vomiting was observed in 64% of patients with TROPDEX as compared with 14% with METDEX (P < 0.01). While complete plus major control of acute vomiting was observed in 84% with TROPDEX as compared with 58% with METDEX. The mean vomiting episodes on day 1 were 1.4 with TROPDEX as compared with 3.5 with METDEX (P < 0.01). There was, however, no significant difference between the two regimens in the control of delayed vomiting. 5. When patients randomized to TROPDEX in the second cycle were compared with those with TROPDEX in the first cycle, the antiemetic efficacy was reduced, with mean acute vomiting episodes of 2 in the former compared with 0.8 in the latter (P < 0.01). 6. The most common adverse effect observed was headache in TROPDEX (27%) and dizziness in METDEX (40%). 7. In conclusion, the antiemetic regimen TROPDEX is effective in Chinese patients receiving high dose cisplatin chemotherapy and is well tolerated. It is better than conventional METDEX regimen in the control of acute vomiting, but not in the control of delayed vomiting.
Antiemetics↗
Surgical magnification for intracapsular cataract surgery in a rural hospital.
Intracapsular cataract extraction is still the most common type of operation performed in India, especially in eye camps, and most of these are done without magnification. To assess the surgical outcome of intracapsular cataract surgery in a rural hospital with various magnifying systems, 121 consecutive eyes (121 patients) with uncomplicated cataract were randomly allocated to surgery with the operating microscope, binocular loupe or unaided eye. The surgery was performed by either consultants or first year residents. The best corrected vision at least four weeks post-operatively was compared among the three groups. The performance between the consultants and the junior residents was also compared. The improvement of surgical outcome with magnification was statistically significant (p = 0.0045); and clinically important with a relative risk reduction of 60.6%. The comparison between microscope and loupe magnification did not show a significant difference (p = 0.24). However, with an operating microscope, the consultants performed significantly better than the junior residents. These findings suggest that the use of magnification in intracapsular cataract extraction provides a definite advantage over an unaided eye and that the binocular loupe is a good alternative to the operating microscope in this kind of surgery.
Adult↗
The action of methimazole and L-thyroxine in radioiodine therapy: a prospective study on the incidence of hypothyroidism.
Thiourea drugs have been postulated to possess radioprotective property. We studied the effect of adjunctive antithyroid drugs (ATD) and L-thyroxine (L-T4) on the result of radioiodine (RAI) 131I therapy and determined the incidence of hypothyroidism and relapse of hyperthyroidism. One hundred and fifty-nine patients with Graves' disease were randomized prospectively to receive either RAI alone or adjunctive ATD in a form of block-replacement regimen of methimazole (MMI) plus L-T4 for 6 months. The patients were observed for a mean period of 4.6 (range 2-10) years. The incidence of permanent hypothyroidism was studied and the effect of ATD on iodine kinetics was analyzed. The cumulative incidence of hypothyroidism in the ATD group was significantly lower than the RAI group (p = 0.0009), and the difference is accounted by a reduction of early hypothyroidism within 12 months from 20.2 to 3.7% (p = 0.003). The incidence of late hypothyroidism was similar between the two groups. Treatment with ATD did not affect the one dose cure rate with RAI (61.2 vs 55.5%, p = NS), but the time to achieve euthyroidism was significantly earlier with adjunctive ATD (2 vs 8 weeks, p < 0.02). The incidence of relapse within the first year after one dose was also similar between the two groups (38.7 vs 44.5%, p = NS). Comparing the kinetics of the therapeutic dose with a tracer dose, patients receiving MMI were found to be underdosed by 22% (p = 0.003) and the biological half-life was significantly shortened. We conclude that ATD rendered euthyroidism earlier without compromising the one dose cure rate of RAI.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Radiotherapy for nasopharyngeal carcinoma: shielding the pituitary may improve therapeutic ratio.
PURPOSE: Nasopharyngeal carcinoma (NPC) is well known for its invasiveness and erosion of the base of the skull is not uncommon. Before the advent of computed tomography, the evaluation of the base of the skull was by plain radiography. Because of the low sensitivity of these investigations, traditional teaching has included the sphenoid sinus in the volume of irradiation. Increase in longevity of patients allows the manifestation and documentation of the long-term sequelae of irradiating the hypothalamic-pituitary axis and the temporal lobes. This study is an attempt to evaluate whether the hypothalamic-pituitary axis can be shielded from the target volume in a proportion of NPC patients. METHODS AND MATERIALS: One hundred fifty-two NPC patients with no evidence of erosion of the base of the skull and sphenoid, nor extension to the nasal fossa and ethmoid sinuses were randomized to receive standard radiotherapy covering the whole sphenoid sinus or radiotherapy using a modified technique that shields the pituitary and the anterior part of the hypothalamus. This modified technique also shields a large part of the lower temporal lobes that are otherwise covered by standard treatment portals. The characteristics and treatment of the two subgroups of patients were otherwise comparable. RESULTS: At a median follow-up of 31.5 months, the tumor control between the two subgroups of patients were comparable (p = 0.3928). However, 8 of the 71 patients in the unshielded group had developed symptomatic neuroendocrine complications, while none of the other group did (p = 0.0061). Two patients developed secondary hypothyroidism, one patient developed oligomenorrhoea associated with raised prolactin, and five patients developed temporal lobe necrosis. CONCLUSIONS: The protective effect on neuroendocrine complication of this shield was demonstrated at median follow-up of 31.5 months, and the local control was not jeopardized. Modification of treatment technique as presently described, which is applicable to one-third of NPC patients to improve the therapeutic ratio, is recommended for general use.
Adult↗
Investigation of stiffness and microstructure of joints soldered with gas-oxygen torch and infrared methods.
The stiffness of soldered connectors fabricated with the gas-oxygen torch technique was compared with those fabricated with the infrared technique. Untreated solder materials were used as controls. Untreated solder materials of gold-palladium, palladium-silver, and chromium-cobalt alloys exhibited significantly higher stiffness than the soldered specimens fabricated with either method. There was no significant difference between the gas-oxygen torch and the infrared groups of the gold-palladium and palladium-silver alloys. Photomicrographs revealed that the soldered specimens displayed porosities. For the chromium-cobalt alloy, the infrared group demonstrated significantly higher stiffness than the gas-oxygen torch group. Photomicrographs also disclosed that the chromium-cobalt alloy soldered with the gas-oxygen torch technique had a significant heat-affected zone.
Analysis of Variance↗
Intended epidural anesthesia as possible cause of cauda equina syndrome.
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Aged↗
X-rays destroy the lamellar structure of model membranes.
Lipid membranes undergo a dramatic lamellar-to-non-lamellar phase transformation upon being irradiated with X-rays. The structure change was evidenced by chemical breakdown of the lipid and by a change in the X-ray diffraction properties of the model membrane indicating complete disruption of lamellar stacking. Considering the importance of X-ray diffraction as a structure probe the problem of radiation damage to biological materials must be duly recognized. Because X-ray damage has been shown to be free radical-mediated these results suggest a means by which free radicals accumulating in cells during aging might compromise membrane integrity and contribute to cell death.
Chromatography, Thin Layer↗