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Biomedical subjects

I T Foo

Publications and source records attributed to I T Foo.

At least 19 recordsLinked to original sources
PubMed2000

Ten-year review of a prospective randomized controlled trial of textured versus smooth subglandular silicone gel breast implants.

Although textured silicone breast implants have been shown to reduce the incidence of capsular contracture, there is little evidence if this effect is maintained in the long term. It has been 10 years since the double-blind randomized trial in which 53 patients received either Mentor smooth (26) or textured silicone gel implants (27). Of the 14 patients who were not known to have developed a contracture in the smooth group, 11 were reviewed. Three had bilateral contractures. In the textured group, 18 of the 24 patients not known to have contractures were reviewed. None had developed contractures. At 10 years, the incidence of capsular contracture was 65 percent of patients with smooth implants (an increase of 6 percent on the 3-year results) and 11 percent for the textured implant patients (no change on the 3-year results). A database containing the details of 1100 patients reinforces these results by examining the differences in contracture rates of textured, smooth, and polyurethane-coated implants. The effect of submuscular placement on reducing contracture rates regardless of texturing is discussed, as is the apparent increase in capsular contracture in patients who smoke.

Adult↗
PubMed1999

Pulsed dye laser treatment of telangiectasia after radiotherapy for breast carcinoma.

Telangiectasia formed following exposure to X-ray irradiation have been reported to respond well to the pulsed dye laser system. We present the case of a 34-year-old woman with extensive post-radiotherapy skin telangiectasia of the chest wall and axilla who was treated with six sessions of pulsed dye laser treatment, with a considerable improvement in appearance. We recommend the pulsed dye laser as an option in the treatment of post-radiotherapy telangiectasia.

Adult↗
PubMed1998

Influence of dose of domperidone on the acute ventilatory response to hypoxia in humans.

We have studied the ventilatory responses to acute isocapnic hypoxia (SpO2 78.8 (SD 1.4)% for 10 min) in 10 male volunteers given three different doses of oral domperidone: placebo, domperidone tablets 10 mg, 20 mg or 30 mg every 8 h for 48 h on separate days. Neither baseline ventilation nor the acute hypoxic ventilatory response was significantly different from placebo for any of the domperidone doses. However, hypoxic responses were either increased with increments of domperidone or subjects were not sensitive. We arbitrarily divided subjects into two groups according to their hypoxic response-plasma domperidone concentration relationship. Analysis of subjects (n = 5) who demonstrated at least a 2-litre min-1 increase in ventilation per 10 ng ml-1 increase in plasma domperidone concentration showed the greatest augmentation of hypoxic responses with the 20-mg dose (median 19.45 (range 13.37, 22.30) litre min-1) compared with placebo (median 8.21 (3.74, 9.47)) (P = 0.003). We were unable to predict which subjects would be sensitive to the effects of domperidone.

Adult↗
PubMed1997

Textured or smooth implants for breast augmentation? Three year follow-up of a prospective randomised controlled trial.

Silicone breast implant surface texturing has been shown to reduce the short-term incidence of adverse (Baker III/IV) capsular contracture in augmentation mammaplasty in double-blind randomised controlled trials. It is, however, undetermined whether the textured surface merely delays the onset of severe contracture or its effect on capsular contraction is persistent. The current study reviewed, after three years, 49 of the 53 patients who had undergone subglandular breast augmentation mammaplasty in a randomised double-blind study with textured or smooth silicone gel-filled implants in 1989. The incidence of adverse capsular contracture was 59% for smooth implants and 11% for textured ones (P = 0.001; chi 2 = 10.60). Eight patients (31%) with smooth prostheses underwent breast implant exchange for severe capsular contracture between the one and three year assessments, compared with a revisional surgery rate of only 7.4% (2/27 patients) for the textured group (P < 0.04). These adverse capsular contracture and revisional breast implant surgery rates clearly demonstrate that the effect of textured implants in reducing capsular contracture in augmentation mammaplasty found at one year is maintained at three years, and suggest that it may be long lasting.

Breast Implants↗
PubMed1997

Effect of domperidone on the ventilatory response to transient hyperoxia in patients anaesthetized with isoflurane.

We have studied the ventilatory responses to transient hyperoxia in two groups of patients (n = 10) anaesthetized with isoflurane (0.3 MAC); patients were allocated randomly to receive either domperidone or placebo orally before anaesthesia. In each patient, five two-breath oxygen tests were averaged and minute ventilation (VEinst) or mean inspiratory flow rate (VT/TI) for each post-test breath was compared with the mean values for these variables during baseline ventilation. A decrease to less than the 95% confidence limits of mean baseline values was considered a definite response. According to this definition, transient hyperoxia decreased VEinst in nine of 10 patients in the placebo group and in all patients in the domperidone group. Similar changes occurred in VT/TI, with eight of 10 definite responses in the placebo group and 10 of 10 in the domperidone group. Compared with placebo, in the domperidone group there were larger changes in VEinst (0.30 vs 0.55 litre min-1 (P = 0.05) and VT/TI (8.5 vs 26.6 ml s-1 (P = 0.02)) from respective baselines. Peripheral chemoreceptors appeared to be active during isoflurane anaesthesia and domperidone pretreatment enhanced this activity by increasing respiratory drive.

Adolescent↗
PubMed1996

Human skin histology as demonstrated by Herovici's stain: a guide for the improvement of dermal substitutes for use with cultured keratinocytes?

The potential for the widespread use of cultured keratinocytes for burns treatment is handicapped by practical problems such as fragility, poor take and, often, unsatisfactory cosmesis. Although dermal equivalents reduce these problems there remains a lack of consensus on what is the best structure of such equivalents. At present the commonest support is type I collagen. This histological study, however, using Herovici's stain, clearly shows that in human skin from a variety of anatomical sites the epidermis is not in direct contact with type I collagen but rather with a distinct layer of type III collagen. We suggest that dermal equivalents may have to be constructed so as to include a layer of type III collagen at the interface between the keratinocytes and a type I collagen neo-dermis, so mimicking normal skin structure more closely.

Adolescent↗
PubMed1996

An audit of Björk flap tracheostomies in head and neck plastic surgery.

Patients undergoing head and neck surgery for malignancy especially resection of parts of the upper aerodigestive tracts need a secure airway intra- and postoperatively. A tracheostomy is an effective method of achieving this objective. In our unit the Björk flap technique1 has been the preferred type of tracheostomy. Ninety-five consecutive Björk flap tracheostomies performed by one surgeon preceding major head and neck resection for malignancy in patients aged 17-79 years (median = 61 years) were retrospectively evaluated. The technique was quick and provided a secure airway. The tracheostomy tubes were left in situ for a median of 5 days (range 1-17 days). After extubation subsequent stoma closure was uneventful, 60% healing within 1 week. No patient developed tracheal fistula, clinical tracheal stenosis or cosmetically unacceptable scarring. There was no tracheostomy-related mortality. It is concluded that the Björk flap tracheostomy technique can be safely used in head and neck cancer surgery in adults.

Adolescent↗
PubMed1996

Influence of oral clonidine on the ventilatory response to acute and sustained isocapnic hypoxia in human males.

Animal studies suggest that alpha 2 agonists inhibit the chemoreceptor response to hypoxia. We have examined the effect of oral clonidine on the ventilatory response to sustained, isocapnic hypoxia (SpO2 79.7% (SD 1.1%) for 20 min) in eight male subjects. The hypoxic ventilatory response was measured before and after both clonidine and placebo. Clonidine had no significant effect on baseline ventilation or gas exchange. After clonidine, the acute hypoxic response (AHR) (mean 5.81 (95% confidence limits 1.94, 9.68) litre min-1) was significantly less than control (10.40 (5.97, 14.83) litre min-1) and hypoxic ventilatory decline (HVD) (3.42(2.35, 4.49) litre min-1) was also significantly less than control (6.49(3.92, 9.06) litre min-1) (P < 0.05). After placebo, AHR was similar to control but HVD was significantly larger (6.82(5.28, 8.36) litre min-1) than control (4.79(3.03, 6.55) litre min-1) (P < 0.05). Thus clonidine reduced both AHR and HVD but the absolute level of ventilation at the end of hypoxia was unchanged.

Acute Disease↗
PubMed1995

A picropolychrome staining technique applied to Dupuytren's tissue.

Although the histology of Duputyren's tissue is well-documented, conventional stains do not distinguish between the different types of collagen which biochemistry and immunochemistry suggest are present. Duputyren's specimens [nodules (n = 26), cords (n = 15) and dermofasciectomies (n = 6)] were stained with haematoxylin and eosin, Van Gieson's Mallory's, Masson's, and Herovici's picropolychrome stain, and examined for both cellularity and collagen staining characteristics. All stains illustrated the marked cellularity of the nodules, contrasting with a paucity of cells within the cords. The first four stains demonstrated uniformity of the collagen staining within the tissues. Herovici's picropolychrome, however, showed distinct staining patterns for the dermis, nodules and cords, with both purple/red and blue areas. Other studies suggest that those fibres stained purple/red and blue are types I and III collagens respectively. These findings may shed further light on the tissue of origin of Duputyren's disease.

Aged↗
PubMed1995

Interaction of the effects of domperidone and sub-anaesthetic concentrations of isoflurane on the immediate and sustained hypoxic ventilatory response in humans.

Twenty normal male subjects with brisk hypoxic ventilatory responses were recruited and ventilatory responses to sustained isocapnic hypoxia (SaO2 80.4 (SD 1.3)% for 20 min) were studied on separate days under four conditions: hypoxia alone, with or without domperidone, and 0.1 MAC of end-tidal isoflurane, with or without domperidone. Ventilatory variables were subjected to analysis of variance with estimation of the effects of isoflurane and domperidone, and their interaction. Isoflurane reduced the initial increase in ventilation significantly by 3.12 (95% confidence limits 1.69, 4.55) litre min-1 (P < 0.05) and domperidone increased the initial increase in ventilation by 1.78 (0.35, 3.21) litre min-1 (P < 0.05). Neither isoflurane nor domperidone affected the subsequent ventilatory decline. No interaction was found between these agents. These results confirm that 0.1 MAC of isoflurane suppressed the initial hypoxic ventilatory response but not the subsequent ventilatory decline when hypoxia was sustained. Domperidone offset the suppressive effect of isoflurane on the hypoxic ventilatory response but no interaction was detected.

Adult↗
PubMed1995

Does sleep enhance the effect of subanesthetic isoflurane on hypoxic ventilation?

After surgery, patients may receive little audiovisual stimulation and may sleep. Lack of audiovisual stimulation enhances the suppression of the hypoxic ventilatory response (HVR) by 0.1 minimum alveolar anesthetic concentration (MAC) isoflurane. Sleep also reduces the HVR and may thus increase the risk of hypoxia in patients at this time. We therefore measured the ventilatory response in volunteers to a sustained step hypoxic stimulus (mean arterial oxygen saturation [SaO2] 80% [SEM 0.3] for 20 min) in the presence of 0.1 MAC isoflurane, with subjects in the awake and asleep states. The behavioral states were studied in random order in nine male subjects. The combination of isoflurane and sleep significantly reduced (P < 0.05) normoxic ventilation (6.71 [0.39] vs 8.24 [0.29] L/min) and increased end-tidal PCO2 (PETCO2) (43.1 [0.5] vs 40.4 [0.8] mm Hg) compared with the awake state. However, ventilation was similar in the asleep and awake states during early (15.10 [1.35] vs 15.50 [1.61] L/min) and late (10.45 [0.97] vs 11.03 [0.99] L/min) hypoxia in the presence of isoflurane. Thus sleep did not reduce ventilation during hypoxia in the presence of isoflurane sedation. The increase in PETCO2 during sleep may have offset suppression of the HVR.

Adult↗
PubMed1993

Free tissue transfers to the upper limb.

90 consecutive free tissue transfers to the upper limb have been performed in 75 patients (33 children and 42 adults) by one surgeon over a 3-year period. The average age for children was 5 years, and 25 years in adults. 17 transfers were performed as emergency or urgent procedures. The main indications were congenital and traumatic defects. Included in this series were 44 toe transfers, 28 lateral arm flaps and six functional muscle transfers. The overall success rate was 99%. The re-exploration rate was 5.6% with only one failure. There were no failures in children.

Adolescent↗
PubMed1992

Intracellular actin as a marker for myofibroblasts in vitro.

BACKGROUND: Myofibroblasts are found in a wide variety of normal tissues and pathological conditions. It is suggested that myofibroblasts are derived from normal fibroblasts and share with smooth muscle cells the expression of actin microfilament bundles. The aim of this study was to establish if the myofibroblast phenotype from tissue expander capsules and Dupuytren's nodules could be distinguished from normal dermal fibroblasts by quantitation of intracellular actin and the ratio of polymerized (filamentous) actin to nonpolymerized (globular) actin. EXPERIMENTAL DESIGN: Cell lines were established from six patients from each group. In addition to quantitation of intracellular actin, the cells were characterized by criteria of light microscopy, ultrastructure, actin immunofluorescence, and growth rates. RESULTS: Dermal fibroblasts were the smallest and the most spindle-shaped but grew rapidly and had few actin microfilament bundles. By contrast, myofibroblasts from expander capsules were larger and more stellate, proliferated slowly, and had the most prominent microfilament arrays. Cells from Dupuytren's nodules were intermediate in phenotype. Substantial and significant differences in intracellular actin contents were found, ranging from 0.69 +/- 0.05 micrograms/10(4) cells in fibroblasts and 0.77 +/- 0.15 micrograms/10(4) cells for Dupuytren's nodule cells to 1.46 +/- 0.44 micrograms/10(4) cells in expander capsule myofibroblasts (p < 0.05). Similar findings were found with respect to ratios of fibroblast to globular actins, being 0.22 for fibroblasts and 0.38 for Dupuytren's nodule cells compared with 0.70 for expander capsule myofibroblasts (p < 0.01). CONCLUSIONS: Measurement of intracellular actin contents and fibroblast:globular actin ratios offers a rapid, sensitive, and reliable technique for establishment of the myofibroblast phenotype and has considerable advantages over traditional ultrastructural approaches for the study of myofibroblast differentiation/regression and in vitro responses to experimental manipulation.

Actins↗
PubMed1990

Management of burns in major disasters.

This paper discusses the problems of handling major burns in disasters with particular reference to the disaster that occurred in Bradford. Several major features of the Bradford fire, in which 56 people died, made its management much simpler than might be expected in subsequent burns disasters; these are discussed. Lessons that have been learned from handling this disaster are indicated.

Burns↗