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Biomedical subjects

T H Wong

Publications and source records attributed to T H Wong.

14 recordsLinked to original sources
PubMed2005

Hip fractures in nonagenarians--a study on operative and non-operative management.

Hip fractures in nonagenarians represent a special group because of their advanced age and co-morbidities. Surgery is advocated for their younger counterparts but may not appear desirable in nonagenarians. Eighty-four patients were studied over a 2-year period. There were 73 female and 11 male patients. Forty-seven patients sustained an intertrochanteric fracture of the femur. 37 suffered a neck of femur fracture. ASA score of II was the largest group with 51. At least 62 had one co-morbidity or more; 46 were considered demented with a mental test score of less than 7. The mean length of stay was 31 days. Treatment consisted of either traction or surgery. Forty-six patients were managed surgically and 38 non-surgically. Patient review was done 2 years after the fracture. The overall rate of complications was 52% for the operative and non-operative groups. Death outcome at 24 months was not significantly affected by ASA status, number of co-morbidities at admission, or between surgical and non-surgical treatment. However, there was statistical significance between death and the mini-mental test score of less than 7 (P < 0.05). Forty-three patients were still alive after 2 years; of which 27 had been treated surgically and 16 non-surgically. The overall mortality in both operative and non-operative groups is 49%. Surgery significantly increases the ability for independent ambulation (P < 0.01). Therefore the outcome of non-operative and non-operative treatment in nonagenarians with hip fractures is poor due to the high rates of mortality and morbidity.

Aged↗
PubMed2004

Descemet membrane detachment caused by hydrogen peroxide injury.

OBJECTIVE: To describe a patient who developed a Descemet membrane detachment after hydrogen peroxide injury with successful reattachment by intracameral injection of sulfur hexafluoride gas. METHODS: Case report. RESULTS: The right eye of a 40-year-old man was exposed to 35% hydrogen peroxide. This resulted in a central corneal epithelial defect, corneal edema, a localized detachment of Descemet membrane, and a gas bubble between the posterior corneal stroma and Descemet membrane. The Descemet membrane detachment persisted after reabsorption of the gas bubble. Successful reattachment of Descemet membrane was achieved with injection of 0.15 mL of 20% sulfur hexafluoride gas into the anterior chamber. CONCLUSION: Hydrogen peroxide ocular injury may cause Descemet membrane detachment, and successful reattachment may be achieved with intracameral injection of 20% sulfur hexafluoride gas.

Adult↗
PubMed2001

Plesiomonas shigelloides enters polarized human intestinal Caco-2 cells in an in vitro model system.

This study provides the first definitive evidence that the gram-negative bacterium Plesiomonas shigelloides adheres to and enters eukaryotic intestinal host cells in vitro. P. shigelloides is increasingly regarded as an emerging enteric pathogen and has been implicated in intestinal and extraintestinal infections in humans. However, the establishment of its true role in enteric disease has been hindered by inadequacies in experimental design, deficiencies in clinical diagnosis, and the lack of an appropriate animal model. In this investigation, an in vitro system was used to evaluate plesiomonad pathogenesis. Differentiated epithelium-derived Caco-2 cell monolayers inoculated apically with 12 isolates of P. shigelloides from clinical (intestinal) origins were examined at high resolution using transmission electron microscopy. Bacterial cells were observed adhering to intact microvilli and to the plasma membrane on both the apical and the basal surfaces of the monolayer. The bacteria entered the Caco-2 cells and were observed enclosed in single and multiple membrane-bound vacuoles within the host cell cytoplasm. This observation suggests that initial uptake may occur through a phagocytic-like process, as has been documented for many other enteropathogens. P. shigelloides also was noted free in the cytosol of Caco-2 cells, suggesting escape from cytoplasmic vacuoles. Differences in invasion phenotypes were revealed, suggesting the possibility that, like Escherichia coli, P. shigelloides comprises different pathogenic phenotypes.

Bacterial Adhesion↗
PubMed2000

Induction of human neutrophil apoptosis by nitric oxide donors: evidence for a caspase-dependent, cyclic-GMP-independent, mechanism.

This study investigated the regulatory effects of the major inflammatory mediator, nitric oxide (NO), on human neutrophil apoptosis in vitro. Co-culture of human neutrophils with the NO donors GEA 3162 (1,2,3,4-oxatriazolium,5-amino-3-(3,4-dichlorophenyl)-chloride) (10-100 microM) and 3-morpholino-sydnonimine (SIN-1) (0.3-3 mM) caused a dramatic and concentration-dependent induction of apoptosis. However, N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced neutrophil activation (actin reorganization and chemotaxis) was inhibited by GEA 3162 treatment. The pro-apoptotic effects of the NO donors were (i) unaffected by the soluble guanylate cyclase inhibitor LY-83583 (6-anilino-5,8-quinolinedione; 100 microM), (ii) antagonized by superoxide dismutase (6 microg/mL), (iii) mimicked by exogenous peroxynitrite (at concentrations >100 microM), and (iv) inhibited by the caspase inhibitor Z-Val-Ala-DL-Asp-fluoromethylketone (100 microM). The pro-apoptotic effect of the NO donors was not mimicked by the cell-permeable cyclic nucleotide analogue, N6,2-O-dibutyrylguanosine-3',5'-cyclic monophosphate (dibutyryl-cGMP) at concentrations < or =0.2 mM. Indeed, at high concentrations (> or =2 mM), dibutyryl-cGMP caused an inhibition of apoptosis. These results suggest that NO-mediated apoptosis, although caspase-dependent, is mediated by a cGMP-independent mechanism and involves the concurrent generation of oxygen free radicals and, potentially, peroxynitrite. Our data reveal a unique role for NO in inflammatory responses with differential effects upon neutrophil activation and survival, with important implications for the successful resolution of inflammation.

Adult↗
PubMed2000

Pseudarthrosis repair. Autogenous iliac crest versus femoral ring allograft.

Pseudarthrosis repair in the lumbar spine is one of the most challenging problems faced by spine surgeons. Historically high failure rates with posterior repair have led to the use of anterior lumbar interbody fusion with tricortical iliac crest autograft in these difficult cases. More recently, femoral ring allografts packed with autograft bone have been advocated as another method that would decrease donor site morbidity. Two series of patients underwent anterior lumbar interbody fusion with anterior instrumentation to repair pseudarthrosis (Group I, 33 patients with tricortical autogenous iliac crest and Group II, 20 patients with femoral ring allografts). At minimum 2-year followup, there was no difference in fusion rates (Group I, 32 of 33 versus Group II, 20 of 20). Patients in Group I had radiographic fusion develop more rapidly than patients in Group II (12 months versus 18 months), but a significant proportion of patients in Group I (35%) had an average of 2 mm of graft subsidence. Despite excellent fusion rates in both groups, functional outcomes were not as good with only 28% of patients in Group I and 36% of patients in Group II returning to work. Using anterior instrumentation, anterior interbody fusion offers an excellent method to repair pseudarthrosis using femoral ring allografts or autogenous iliac crest. However, femoral ring allografts offer the potential to decrease donor site morbidity, allowing the surgeon to treat multiple spine levels.

Bone Transplantation↗
PubMed2000

Squamous cell carcinoma arising in a cutaneous epidermal cyst--a case report.

INTRODUCTION: Cutaneous epidermal cysts are common lesions, but fortunately, malignant transformation of their epithelium is rare. There are only a few cases mentioned in recent literature, mostly occurring in epidermal cysts in the head and neck region. CLINICAL PICTURE: We present a case of malignant transformation in a long-standing buttock epidermal cyst, presenting a month after trauma to the cyst. TREATMENT: An excision biopsy and rotation flap was done. When the pathology was confirmed, a second resection was carried out and the defect covered with a free latissimus dorsi flap, a buttock rotation flap and a posterior thigh rotation flap. CONCLUSION: Although malignant transformation is rare, this case illustrates the importance of routine histology in excision of epidermal cysts.

Biopsy↗
PubMed1997

Atrophic pigmented dermatofibrosarcoma presenting as infraorbital hyperpigmentation.

BACKGROUND: Pigmented dermatofibrosarcoma is a rare tumor of the skin and constitutes 1-5% of all dermatofibrosarcoma. Most cases present as polypoid multinodular growth. Occasional cases may be atrophic. We report an extraordinary case with progressive infraorbital atrophy. OBSERVATION: A 24-year-old woman came to us for a diffuse bluish atrophic lesion over the left infraorbital area. The lesion progressed gradually over 2 years. Histologic examination revealed mature spindle cell proliferation in the lower dermis and hypodermis. Interspersed were some heavily pigmented melanocytes. CONCLUSION: We report an unusual case of progressive bluish discoloration and atrophy of the infraorbital area. This is a rare manifestation of dermatofibrosarcoma.

Adult↗
PubMed1993

The solitary thyroid nodule revisited.

A series of 195 clinically solitary thyroid nodules is presented and compared with a matching series reported a decade ago. Changes in the pattern of presentation, preoperative diagnosis and options of operative management are highlighted. Although the pattern of presentation has not changed significantly over the last decade, there was a shift noted towards reliance on fine needle aspiration for preoperative diagnosis. The false negative rate was two percent in this series and there were no false positives. There was also a shift towards more conservative surgery in the form of "nodulectomies" in the present series compared to the previous one. The incidence of malignancy in this series was 10.2 percent.

Adolescent↗
PubMed1991

Acute gall bladder perforation--a dilemma in early diagnosis.

Gall bladder perforation is a rare complication of cholecystitis. A definitive diagnosis is uncommon before surgery and the morbidity and mortality associated with this condition are high. We report six patients with gall bladder perforation to show the difficulty of making an early diagnosis. The history and the clinical findings of these patients are reviewed to highlight diagnostic pitfalls.

Adult↗
PubMed1990

The surgical treatment of squamous cell carcinoma of the oesophagus in Singapore.

In a retrospective study, we reviewed 97 consecutive cases of squamous cell carcinoma collected over a five-year period (1978-1983). Resection of the tumour was possible in 30 out of 40 patients subjected to surgery. Of these 30 patients, five died within 30 days of surgery. Eight patients who underwent oesophageal resection were still alive after five years and apparently cured. Bypass surgery for unresectable lesions in six patients were complicated by anastomotic leakage in three patients. Patients unsuitable for surgical resection were treated using Celestin tube insertion or radiation. Mean survival in 13 patients with Celestin tube insertion was 4.1 months. Of 48 patients who were treated by radiotherapy, two lived beyond five years. Surgical resection restores swallowing effectively and offers a 25% chance of cure and should be done in fit patients. In unfit patients with advanced disease, palliation from the use of radiotherapy and Celestin tube insertion were poor. Newer techniques such as endoscopic laser recanalisation and bicap hyperthermia may need to be considered for palliation in this group of patients.

Adult↗
PubMed1989

Outcome of failure in clearing the oesophageal margin in total gastrectomy for adenocarcinoma.

Failure to clear the oesophageal margin in total gastrectomy for adenocarcinoma is believed to be a major cause of mortality and morbidity. The incidence of histologically positive margin could range from 7.3 to 74%. Forty nine cases of total gastrectomy for adenocarcinoma were reviewed and nine (18%) had a positive oesophageal margin. One of the nine patients died on the second postoperative day from technical difficulty: the rest did not have anastomotic leaks. They all eventually died of metastatic disease in 3-20 months. Two had mild dysphagic symptoms which did not require active intervention. It is concluded that a histologically positive oesophageal margin in total gastrectomy does not preclude good anastomotic healing. Sound surgical judgement is required to balance the risk of leaving a positive margin and the risk of an extended operative procedure particularly when majority of the total gastrectomies are palliative rather than curative.

Adenocarcinoma↗
PubMed1989

Effect of a direct current field on axons after experimental spinal cord injury.

There is evidence that direct current (DC) stimulation promotes neurologic recovery in spinal cord injury. The authors conducted a morphometric analysis of axons at the site of spinal cord injury in adult rats treated with a DC field. Ten rats received a 17-g and 15 rats a 53-g clip compression injury and were treated with either a sham (control) or a functioning DC stimulator for 8 weeks. Five normal rats were also assessed. There was a significant relation (p less than 0.0001) between the severity of injury and the number of axons at the injury site. After the 17-g injury, there was no significant difference in the number of axons between control and treated rats. However, after the 53-g injury, there were significantly (p less than 0.05) more axons in treated than control rats. Both degrees of injury caused preferential destruction of large-calibre axons. Subsequent analysis showed that the axon diameter of treated rats with 17-g or 53-g injury was significantly greater (p less than 0.05) than that of control rats with 17-g or 53-g injury. These data, for the first time, show that the application of a DC field increases the number and calibre of axons at the site of a spinal cord injury and enhances the survival or regrowth of axons following spinal cord injury in the rat.

Animals↗