Plastic surgery.
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Guided Tissue Regeneration↗
Biomedical subjects
R Sanders
Publications and source records attributed to R Sanders.
Plastic Surgery Forum.
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Congresses as Topic↗
Cellular proliferation characteristics do not account for the behaviour of horrifying basal cell carcinoma. A comparison of the growth fraction of horrifying and non horrifying tumours.
This study compared the clinical features, histological subtype, growth fraction (by Ki67 immunohistochemistry) and proliferation pattern of 22 clinically defined horrifying basal cell carcinoma compared to 81 non horrifying lesions. Late presentation was associated with half of the horrifying tumours. The other half developed horrifying tumours despite early intervention. The horrifying tumours exhibited a variety of histological growth patterns. A total of 50% were infiltrative, 23% nodular and 18% micronodular. There was no difference in the growth fraction or proliferation pattern between horrifying and non horrifying tumours of similar growth pattern (P = ns), although infiltrative tumours in either group exhibited a significantly higher growth fraction than nodular tumours (P < 0.01). This suggests that there is no intrinsic biological difference between horrifying and non horrifying tumours to account for their behaviour. We conclude that late presentation, failed or inadequate early management especially of infiltrative tumours (and other subtypes) determines the development of horrifying tumours.
Adult↗
The clinical significance of c-myc oncogene expression in melanomas of the scalp.
Melanomas of the scalp are rare and have a poorer prognosis than melanomas arising at other cutaneous sites. In order to study the biology of this disease, the activity of the c-myc oncogene was studied in tumours from 25 patients with scalp melanoma using the technique of flow cytometry. Survival analysis revealed that stratification of patients according to oncogene activity provided a prognostic marker with shorter overall survival (log rank test, chi 2 = 3.9, P = 0.05) in tumours with high nuclear c-myc oncoprotein positivity. These results support our previous studies of the prognostic value of c-myc expression in melanoma and suggest that estimation of c-myc oncoprotein may be of clinical significance in identifying high risk patients.
Adult↗
Comparison of cloth gloves used in orthopaedic surgery: a clinical and experimental evaluation.
OBJECTIVES: (a) To compare the effectiveness of five cloth gloves for cut resistance and their ability to prevent inner latex glove perforation. (b) To evaluate the safety, efficacy, and comfort of the outer gloves when reused. SETTING: Tertiary care level I trauma hospital and biomechanics laboratory. METHODS: Laboratory evaluation consisting of assessing cut resistance and fabric deterioration and clinical assessment of all cloth gloves worn as a liner between two latex gloves. RESULTS: Laboratory testing demonstrated significant differences in cut resistance, with gloves divided into three groups: most resistant (Centurion, which required over 3,000 slices or 1,300 chops to failure), resistant (MedArmor, failing at eighty-five slices or 121 chops; Paraderm, failing at thirty-eight slices or ninety-four chops; and Repel, failing at forty-six slices or seventy-five chops), and least resistant (Protek, failing at two slices and less than two chops). Clinically, 3 percent of all the inner latex gloves demonstrated a perforation, with no violation of the skin in any of the five types of cloth gloves used. Only the Protek and MedArmor cloth gloves were positively ranked for comfort. CONCLUSION: All gloves provided equal protection with respect to inner latex glove perforation during all of the orthopaedic procedures, with comfort being the most important variable. Gloves should be selected based on comfort, because it appears that all gloves provide equal protection during surgery regardless of the material woven into the fabric.
Equipment Failure Analysis↗
An analysis of p16 protein expression in sporadic malignant melanoma.
Inactivation of p16 tumour suppressor gene has been reported frequently in melanoma cell lines, and mutations have been detected in familial melanoma kindreds. The aim of this study was to assess the role of p16 inactivation in melanocytic progression by measuring the level of p16 protein in a range of sporadic, benign and malignant melanocytic lesions. Using dual parameter flow cytometry, p16 protein expression was measured in 30 benign melanocytic naevi, 38 primary and 51 metastatic melanomas. A high level of p16 expression was demonstrated in benign melanocytic naevi (96% median nuclear positivity), with a significant reduction in primary melanomas (69%, P < 0.001). The median nuclear positivity of primary melanomas was significantly higher (P < 0.03) than the level of expression in metastatic lesions (median positivity 37%). A progressive loss of p16 expression was demonstrated from benign melanocytic naevi through to primary and metastatic lesions. These data suggest that loss of p16 protein expression is not only associated with the early transformation of benign lesions, but also with the later stages of malignant progression.
Adolescent↗
Intracellular and extracellular blood magnesium fractions in hemodialysis patients; is the ionized fraction a measure of magnesium excess?
To establish the best measure for determining magnesium overload, we measured ionized and total magnesium in serum and mononuclear blood cells and total magnesium in erythrocytes in blood of 23 hemodialysis patients, known for their disturbed magnesium homeostasis. When comparing the mean magnesium values obtained in the patient population with those of a control population, all of these magnesium markers, including the biologically active fractions, were significantly (P < 0.05) increased. Because serum total magnesium was not increased in all dialysis patients studied, the population was divided into two groups, according to total serum magnesium > 1.0 mmol/L or less than that. Results in these two populations showed that ionized serum magnesium and ionized magnesium in mononuclear blood cells might give a better indication about the magnesium status of the tested patients than the currently used total serum magnesium data. However, neither of the two markers, especially ionized serum magnesium, was able to discriminate fully between normal magnesium homeostasis and magnesium excess. We therefore conclude that the two ionized magnesium markers offer minimal advantage for this discrimination, and that the total magnesium concentration in serum remains the measurement of choice.
Adult↗
Eye disease associated with handling pet tarantulas: three case reports.
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Animals↗
Poliomyelitis immunisation programmes.
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China↗
The prevalence of surface antigen variants of hepatitis B virus in Papua New Guinea, South Africa, and Sardinia.
Three assays, one based on monoclonal antibodies and the others on polyclonal antibodies, were employed to detect hepatitis B surface antigen (HBsAg)-reactive samples in both vaccinated and unvaccinated populations in areas of the world where hepatitis B virus (HBV) is endemic. Any discordant sera were tested by polymerase chain reaction (PCR) to confirm current infection, and sequence data were obtained from the DNA coding for the major hydrophilic region (MHR) of HBsAg of those samples positive for PCR. In all countries studied, samples that reacted in one HBsAg assay but not another were found. In the most extreme case, about 5% of viremic sera in Papua New Guinea were nonreactive in the monoclonal HBsAg assay; 9 of the 13 PCR-positive samples had novel or once-described variants, or a variant out of its usual genotype context. In South Africa, samples with sequences of subtype ayw2 reacted poorly, particularly in the polyclonal assay. Two had novel variants. In Sardinia, antibody to hepatitis B core antigen (anti-HBc) was analyzed as a marker of infection. A significant proportion of anti-HBc-positive, but monoclonal HBsAg-negative, vaccinees and unvaccinated persons were found to be PCR positive, as were some individuals without any markers of hepatitis B virus infection. Five more novel variants were found in these groups. There are implications for the design of HBsAg assays, which may have to be modified according to local sequence variability. Not all discordant samples were explained by variants, indicating that assay sensitivity is fundamental to diagnostic efficacy. Overall, this study defined 16 novel variants and 2 new potential epitope clusters.
Amino Acid Sequence↗
The clinical significance of oncogene expression in subungual melanoma.
Subungual melanoma is a particularly aggressive tumour. However, biological investigations of its behaviour are presently lacking due to its comparative rarity. In order to study the biology of this disease, the activity of the c-myc oncogene was studied in tumours from 24 patients with subungual melanoma using the technique of flow cytometry. High levels of oncoprotein were found in all tumours and exceeded that documented in other varieties of cutaneous melanoma. Survival analysis revealed that stratification of patients according to oncogene activity provided a useful prognostic marker with shorter disease free interval (log rank test, chi 2 = 6.6, P = 0.01) and overall survival (log rank test, chi 2 = 3.6, P = 0.07) in tumours with high oncoprotein levels. This is the first study to investigate oncogene expression in subungual disease and supports its potential application as a prognostic marker.
Adult↗
Measurement of c-myc oncoprotein provides an independent prognostic marker for regional metastatic melanoma.
Patients with melanoma who develop nodal metastatic disease represent a group with heterogeneous clinical outcome. Nodal positivity remains the most accurate prognostic marker for regional melanoma although it fails to predict outcome in a significant number of patients. Recent studies have illustrated the prognostic potential of c-myc oncogene expression in melanoma. The aim of this study was to measure c-myc oncoprotein in a series of regional metastatic specimens from 48 patients, and evaluate its use as a marker of clinical outcome. Oncoprotein expression was detected in 46 (96%) of the tumours with a median positivity of 68% (range 0-98%). Survival analysis revealed a significant association between oncoprotein positivity and survival (Long-Rank test, chi 2 = 15.2, P < 0.001). Multivariate analysis of outcome showed c-myc oncoprotein to be an independent prognostic marker more accurate than all other clinicopathological parameters including nodal positivity (chi 2 = 8.34, P = 0.003). Estimation of c-myc oncoprotein is therefore recommended as a powerful prognostic marker for regional metastatic melanoma.
Aged↗
Precision of the magnesium determination in mononuclear blood cells and erythrocytes.
OBJECTIVE: Establishing the analytical variation and reproducibility of the intracellular magnesium (Mg) assay in mononuclear blood cells (MBC) and erythrocytes (RBC). DESIGN AND METHODS: We assessed the analytical variation of the several determination steps, and the reproducibility for the complete intracellular Mg-assay (combination of preanalytical, analytical, and biological variation). The influence of platelets was determined by comparing Mg concentrations obtained from heparinized blood and defibrinated blood. RESULTS: Coefficients of variation of the several determination steps used in the MBC- and RBC-assay were < or = 5.4%. The overall analytical variation was 5.0-6.8%, and reproducibility of the complete Mg-assay 11.6-14.0%. Mg measurements in MBC (expressed as fmol/cell) obtained from heparinized blood showed significantly higher values than those obtained from defibrinated blood. CONCLUSION: This is the first study to describe in detail reproducibility data for the individual steps in the overall procedure to measure intracellular magnesium. It is shown that results obtained in daily practice should be interpreted with care. Moreover, the removal of platelets is essential in the determination of Mg in MBC.
Blood Specimen Collection↗
Cellular proliferation characteristics of basal cell carcinoma: relationship to clinical subtype and histopathology.
This study investigates the proliferation characteristics of 81 primary basal cell carcinomas (BCC) using detection of the Ki-67 antigen by immunohistochemistry. The tumours were classified into distinct sub-types based on their histological growth pattern and differentiation status. The mean Ki-67 growth fraction was 0.293 and this was found to vary between the different growth patterns, with morpheic, infiltrating and superficial tumours showing the highest levels of proliferation at 0.373, 0.351 and 0.335, respectively; the nodular and micronodular growth patterns were significantly lower at 0.248 and 0.232, respectively. No overall association was seen between proliferation and differentiation status although certain histological growth patterns such as nodular showed a greater propensity to differentiate. Proliferation was related to tumour size, with larger lesions exhibiting higher growth fractions although this may have also been related to tumour subtype as infiltrating and morpheic tumours tended to present with larger tumour diameters. The spatial distribution of proliferating cells by Ki-67 labelling was not related to tumour subtype, differentiation or growth fraction. These studies have shown BCC to possess proliferative characteristics akin to other solid tumours commonly regarded as more rapidly dividing. There was an association between growth fraction and tumour subtype consistent with higher proliferation in the lesions considered to be more aggressive.
Basal Cell Carcinoma↗
Comparison of catecholamine and pressor effects in peribulbar and retrobulbar anaesthesia in cataract surgery.
Peribulbar anaesthesia is now established as an alternative to retrobulbar anaesthesia for cataract surgery. However, the larger volume of anaesthetic solution in the extraconal orbit with the peribulbar technique might carry a higher risk of systemic side-effects. To assess this risk we carried out a prospective randomised comparison of plasma catecholamine and pressor effects between the two methods of anaesthesia in 40 patients. Plasma adrenaline and noradrenaline, heart rate, blood pressure, pain and anxiety were documented before and after local anaesthesia and during surgery. There were no statistically significant differences between the responses of the two groups. Both groups demonstrated a statistically significant rise in plasma adrenaline and heart rate. However, this change was minimal compared with the effects reported after severe stress or general anaesthesia, emphasising the importance of allaying patient anxiety during local anaesthesia. We have therefore shown that the larger volume of extraconal orbital anaesthetic solution with the peribulbar technique produces no greater risk of systemic pressor effects.
Anesthesia, Local↗
Malignant melanoma of the lacrimal sac.
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Aged↗
Development and coordination of the Polio Laboratory Network in the Western Pacific Region of the World Health Organization.
A multitiered network of polio laboratories, consisting of specialized reference laboratories, regional reference laboratories, national laboratories and, in the case of China, provincial laboratories, was established in the Western Pacific Region of the World Health Organization (WHO) in 1992. The network currently consists of 43 laboratories within the Region and is coordinated through the WHO Regional Office in Manila. As the levels and extent of supplementary immunization and acute flaccid paralysis surveillance activities have increased, so has the work load of network laboratories. The total number of stool specimens collected and processed in Polio Laboratory Network laboratories in this WHO region in 1995 exceeded 15,000. With the Region now establishing the criteria necessary for certification of polio-free status, it is essential for the Polio Laboratory Network to establish international confidence in its ability to carry out its role in the eradication of polio.
Asia, Southeastern↗
A theoretical framework for evaluating the sensitivity of surveillance for detecting wild poliovirus: I. Factors affecting detection sensitivity in a person with acute flaccid paralysis.
Surveillance for cases of acute flaccid paralysis provides a means for detecting circulating wild poliovirus in a population and therefore is crucial to the global polio eradication effort. An initial step toward developing a more general framework for understanding the sensitivity of the acute flaccid paralysis surveillance system is presented by first specifying four categories of sensitivity involved: laboratory sensitivity, specimen sensitivity, person sensitivity, and population sensitivity. Using this framework, estimates for specimen sensitivity (the probability that virus will be detected in a specimen collected from an infected person) and the prevalence of infection are derived and applied to surveillance data from three regions. On the basis of the framework, our analysis indicates that a second specimen may significantly increase person sensitivity under some circumstances but provides little improvement under others.
False Negative Reactions↗