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Biomedical subjects

T C Teo

Publications and source records attributed to T C Teo.

12 recordsLinked to original sources

Microvascular soft tissue reconstruction of the digits.

INTRODUCTION: Composite tissue loss to digits following trauma may require flap coverage. Local reconstruction techniques are popular but can result in a functional limitation at the donor site. Small free flaps though complex, may provide a superior alternative. METHOD: We retrospectively reviewed the case-notes of all patients who had a small free flap to a digit following trauma. The time period was 4 years (2000-2004). Sixteen patients with 18 digital free flaps were identified. These comprised of 10 venous flow-through flaps, one lateral arm flap, one great toe to thumb pulp transfer, three first web space flaps from the foot, one medial plantar flap and two free posterior interosseous flaps. All 16 patients were invited for clinical review at an out-patients clinic. Ten patients (11 flaps) attended follow-up. Standardised assessment of outcome in terms of scar quality at both the recipient and donor sites, sensibility, range of motion and function of the hand was completed. RESULTS: Overall the average follow-up period was 14 months, with 16 out of 18 flaps surviving. Of the patients that attended for clinical review, the majority recovered excellent function of the hand (quick-DASH--av. 5.7) with satisfactory aesthetics, minimal pain or limitations in range of motion. The flaps were all soft and durable. Ten flaps recovered protective but not discriminative sensation (only one flap was innervated). The three patients whose donor site was the first-web space of the foot developed significant hypertrophic scarring. CONCLUSION: Small free flaps provide an acceptable method of reconstructing digital defects. Venous flow-through flaps provided the best overall results in this series. The donor site for first-web space flaps is probably unacceptable.

Adolescent↗

Preoperative management of the amputated limb.

Little literature exists on storage and preparation of an amputated limb prior to transfer to a reconstructive plastic surgical unit for possible macroreplantation. This paper describes practical measures used to prolong ischaemia time allowing macroreplantation, tissue harvesting, or fashioning of a useful stump. A simple protocol is used to summarise these points.

Amputation, Traumatic↗

Three cases of successful microvascular ear replantation after bite avulsion injury.

We present three cases of sub-total amputation of the external ear caused by bite avulsion injury. The ears were all successfully replanted despite us being unable to perform a venous anastomosis in one case. These outcomes support attempted microsurgical replantation for total or sub-total amputations of the ear, as successful replantation is the most effective surgical option.

Adolescent↗

Rotation flaps in the treatment of ischial pressure sores--the bigger the better.

Pressure sores are a common problem in paraplegic patients or those otherwise immobilised for long periods of time. Their surgical management is predominantly undertaken by plastic surgeons but other surgeons will also treat them from time to time. We present a case of an ischial pressure sore treated by a general surgeon with a small buttock rotation flap that subsequently broke down with recurrence of the pressure sore. The subsequent surgical management under our care was compromised by his earlier surgery but nevertheless achieved a satisfactory outcome. The need to perform repeat surgery in the future must therefore be borne in mind when planning the initial operation, so that the maximum number of reconstructive options are preserved.

Humans↗

An experimental model to investigate the dynamics of wound contraction.

An excisional wound model in the Hooded Lister rat is described. The methods used to inflict, measure and characterise the process of wound contraction are comprehensively discussed. The model is shown to be reliable, reproducible and capable of detecting the effect of systemically administered prednisolone.

Animals↗

Modifications to the rate of wound contraction by allopurinol.

The effect of allopurinol (50 mg/kg) on the rate of full thickness excisional wound contraction in the Hooded Lister rat was assessed by planimetric and histological examinations. Compared with control animals, those treated with allopurinol showed a significantly lower coefficient of wound area contraction for days 0-7 (p < 0.05) than those of control animals. Histologically, in the allopurinol treated wounds the granulation tissue was less cellular but appeared to contain more collagen. This inhibition by allopurinol of the contraction phase of wound healing associated with an increased quantity of granulation tissue suggests that mediation of the process may involve a complex interaction between the fibroblasts/myofibroblasts and free radicals.

Allopurinol↗

Long-term feeding with structured lipid composed of medium-chain and N-3 fatty acids ameliorates endotoxic shock in guinea pigs.

The metabolic and physiologic responses to 7-hour endotoxin infusion (5.0 mg/kg h) were evaluated in guinea pigs following 6 weeks of dietary enrichment with diets containing either chemically structured lipid (SL) composed of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT) in the form of N-3 polyunsaturated fatty acids (PUFAs), or safflower oil (SO), which is high in N-6 fatty acids. Plasma phospholipid fatty acid profiles, arterial blood pH, PCO2, PO2, HCO3, lactate, blood pressure, oxygen consumption, and energy expenditure were examined. Plasma phospholipid fatty acids profiles reflected dietary intake with SL-fed animals demonstrating a significantly higher N-3 to N-6 fatty acid ratio compared with SO-fed animals. SL-fed animals responded to endotoxemia with a mild metabolic acidosis with respiratory compensation, which was associated with moderate lactatemia (3 mmol/L). SO-fed animals developed a severe metabolic acidosis with acidemia and respiratory compensation, which was associated with hyperlactatemia (8 mmol/L, P less than .05 v SL). No differences were observed in blood pressure, oxygen consumption, energy expenditure, or respiratory quotient during endotoxemia between dietary groups compared with controls. We conclude that diets enriched with structured lipid composed of medium-chain and N-3 fatty acids can attenuate the sequelae of endotoxemia.

Animals↗

Short-term TPN containing n-3 fatty acids ameliorate lactic acidosis induced by endotoxin in guinea pigs.

We evaluated the effect of total parenteral nutrition (TPN) enriched with n-3 fatty acids on the physiologic response to endotoxin in guinea pigs. Animals were randomly assigned to receive TPN differing only in lipid source for 3.5 d. Group 1 received soybean fat emulsion (Intralipid) whereas group 2 received fish (menhaden) oil. During the last 7 h of TPN, animals were further randomized to have either saline or E coli endotoxin added to the infusate. Acid-base status and serum lactate concentrations were determined. Animals infused with soybean fat emulsions and endotoxin developed a significant metabolic acidosis, lactic acidemia, and decrease in mixed venous O2 compared with controls and fish-oil-treated animals (p less than 0.05). The significantly reduced serum lactate and higher mixed venous O2 in fish-oil-infused animals suggests that the underlying mechanism involves improvement in endotoxin-induced tissue hypoperfusion, presumably through alterations in prostaglandin metabolism.

Acid-Base Equilibrium↗

Administration of structured lipid composed of MCT and fish oil reduces net protein catabolism in enterally fed burned rats.

The effects of enteral feeding with safflower oil or a structured lipid (SL) derived from 60% medium-chain triglyceride (MCT) and 40% fish oil (MCT/fish oil) on protein and energy metabolism were compared in gastrostomy-fed burned rats (30% body surface area) by measuring oxygen consumption, carbon dioxide production, nitrogen balance, total liver protein, whole-body leucine kinetics, and rectus muscle and liver protein fractional synthetic rates (FSR, %/day). Male Sprague-Dawley rats (195 +/- 5g) received 50 ml/day of an enteral regimen containing 50 kcal, 2 g amino acids, and 40% nonprotein calories as lipid for three days. Protein kinetics were estimated by using a continuous L-[1-14C] leucine infusion technique on day 2. Thermally injured rats enterally fed MCT/fish oil yielded significantly higher daily and cumulative nitrogen balances (p less than or equal to 0.025) and rectus muscle (39%) FSR (p less than or equal to 0.05) when compared with safflower oil. MCT/fish oil showed a 22% decrease (p less than or equal to 0.005) in per cent flux oxidized and a 7% (p less than or equal to 0.05) decrease in total energy expenditure (TEE) versus safflower oil. A 15% increase in liver FSR was accompanied by a significant elevation (p less than or equal to 0.025) in total liver protein with MCT/fish oil. This novel SL shares the properties of other structured lipids in that it reduces the net protein catabolic effects of burn injury, in part, by influencing tissue protein synthetic rates. The reduction in TEE is unique to MCT/fish oil and may relate to the ability of fish oil to diminish the injury response.

Animals↗

Invited comment: lipids and the development of immune dysfunction and infection.

Excessive W-6 PUFA metabolism due to high levels of dietary fat intake can encourage infection via prolonged inflammation, enhanced Gram negative survival, reticuloendothelial blockage, immunosuppression, and monokine depression. Lipids can influence host immunity by altering eicosanoid metabolism and membrane structure and function. Further investigations are essential to answer questions regarding the levels and properties of various essential fatty acids in TPN lipid emulsions. Combining the features of LCT in the form of W-3 PUFA (fish oil) and MCT in the form of medium-chain triglyceride in a "structured lipid" may decrease infection and may improve survival rates by producing fewer inflammatory eicosanoids of the two- and four-series, and serving as a more "efficient fuel." The introduction of W-3 polyunsaturated fatty acids into the TPN emulsions as well as into normal diets may provide an important therapeutic advance in the pathogenesis of disease. Such unique antiinflammatory properties of W-3 PUFA require intensive research.

Animals↗

The distally based posterior interosseous fasciocutaneous island flap in reconstruction of the hand in leprosy.

In leprosy a functionally useless hand can be the sequelae of resorption of the sensation-impaired thumb and fingers resulting from repeated trauma and infection. When this process shortens the thumb to the level of the proximal phalanx or metacarpal, the effect is to produce a relatively shallow first web space which together with the shortening, can prevent the most basic hand manoeuvre of a pincer or pinch grip. The reconstructive procedure commonly used in this situation is to widen and deepen the web space with a z-plasty combined with excision of the second metacarpal but the result can be inadequate. We have used the posterior interosseous fasciocutaneous island flap, both as a simple and a compound flap, to solve this challenging problem and we report here our experience with four patients.

Adult↗