Biophysical characteristics of skin in diabetes: a controlled study

Background  Cutaneous complications are common in diabetes. Previous assays suggest that hyperglycemia and decreased insulin signal are involved in the impairment of skin function. The aim of this study was to evaluate the biophysical characteristics of skin in patients with diabetes mellitus and compares them with healthy non-diabetic controls.
Objective  To measure biophysical characteristic of skin including transepidermal water loss (TEWL), water content, sebum and skin elasticity in patients with diabetes mellitus and compare them with healthy non-diabetic controls.
Methods  This case-control study was conducted on 38 patients with diabetes and 40 age- and sex-matched healthy people. The biophysical properties of skin including stratum corneum (SC) hydration, sebum content, TEWL and skin elasticity were measured and compared between the two groups at three different locations of the body.
Results  The measurement of SC hydration and TEWL showed no significant difference between diabetics and controls. The skin surface lipids on the forehead but not other sites were significantly lower in the diabetics than in the controls. Acoustic wave propagation speed, a measurement related to skin elasticity, was significantly lower in forearm and forehead of diabetics.
Conclusion  Diabetes affects some functional properties of epidermis and dermis that may responsible for many cutaneous manifestations of diabetes. These results suggest that patients with diabetes mellitus tend to show a normal hydration state of the SC together with decreased sebaceous gland activity and impaired skin elasticity, without any impairment of the SC barrier function.

Conflicts of interest

None declared     

Rhythms, rhymes, and reasons--spectral oscillations in neural cardiovascular control

Cardiovascular neural regulation is an integrated response to a continuous interaction of inhibitory and excitatory stimuli. Neural control of the circulation appears to be coded simultaneously in different modalities as amplitude (strength of signal or tonic activity) and frequency (oscillatory or phasic activity). Changes in tonic activity appear to be accompanied by tightly linked modulations in oscillatory characteristics. This is true within a narrow range of physiologic conditions, and the relationship is eliminated in extreme cardiovascular pathophysiology. Nevertheless, the oscillatory patterns in cardiovascular neural control appear to be widespread so that low and high frequency oscillatory patterns are evident even in sympathetic traffic to skin (Cogliati et al., 2000). Thus, it is likely that there is a functional significance to these oscillations. Recent data from Nafz et al. (1999) suggest that the presence of LF oscillatory characteristics in renal perfusion may attenuate renin-angiotensin activation during renal hypotension. These findings may have direct relevance to poorer outcomes observed in heart failure patients in whom an absence of LF oscillatory power was observed in RR interval and sympathetic traffic (Van de Borne et al., 1997a).     

Assessment of aldehyde dehydrogenase in viable cells

Cytosolic aldehyde dehydrogenase (ALDH), an enzyme responsible for oxidizing intracellular aldehydes, has an important role in ethanol, vitamin A, and cyclophosphamide metabolism. High expression of this enzyme in primitive stem cells from multiple tissues, including bone marrow and intestine, appears to be an important mechanism by which these cells are resistant to cyclophosphamide. However, although hematopoietic stem cells (HSC) express high levels of cytosolic ALDH, isolating viable HSC by their ALDH expression has not been possible because ALDH is an intracellular protein. We found that a fluorescent aldehyde, dansyl aminoacetaldehyde (DAAA), could be used in flow cytometry experiments to isolate viable mouse and human cells based on their ALDH content. The level of dansyl fluorescence exhibited by cells after incubation with DAAA paralleled cytosolic ALDH levels determined by Western blotting and the sensitivity of the cells to cyclophosphamide. Moreover, DAAA appeared to be a more sensitive means of assessing cytosolic ALDH levels than Western blotting. Bone marrow progenitors treated with DAAA proliferated normally. Furthermore, marrow cells expressing high levels of dansyl fluorescence after incubation with DAAA were enriched for hematopoietic progenitors. The ability to isolate viable cells that express high levels of cytosolic ALDH could be an important component of methodology for identifying and purifying HSC and for studying cyclophosphamide-resistant tumor cell populations.     

Preliminary Validation of an Optimally Weighted Patient-Based Utility Index by Application to Randomized Trials in Breast Cancer

ObjectivesTo optimize, apply, and validate a scoring algorithm that provides a utility index from a cancer-specific quality of life questionnaire called the Utility-Based Questionnaire-Cancer (UBQ-C) using data sets from randomized trials in breast cancer. The index is designed to reflect the perspective of cancer patients in a specific clinical context so as to best inform clinical decisions.MethodsWe applied the UBQ-C scoring algorithm to trials of chemotherapy for advanced (n = 325) and early (n = 126) breast cancer. The algorithm converts UBQ-C subscales into a subset index, and combines it with a global health status item into an overall HRQL index, which is then converted to a utility index using a power transformation. The optimal subscale weights were determined by their correlations with the global scale in the relevant data set. The validity of the utility index was tested against other patient characteristics.ResultsOptimal weights (range 0–1) for the subset index in advanced (early) breast cancer were: physical function 0.20 (0.09); social/usual activities 0.23 (0.25); self-care 0.04 (0.01); and distresses 0.53 (0.64). Weights for the overall HRQL index were health status 0.66 (0.63) and subset index 0.34 (0.37). The utility index discriminated between breast cancer that was advanced rather than early (means 0.88 vs. 0.94, P < 0.0001) and was responsive to the toxic effects of chemotherapy in early breast cancer (mean change 0.07, P < 0.0001).ConclusionsThe scoring algorithm for the UBQ-C utility index can be optimized in different clinical contexts to reflect the relative importance of different aspects of quality of life to the patients in a trial. It can be used to generate sensitive and responsive utility scores, and quality-adjusted life-years that can be used within a trial to compare the net benefit of treatments and inform clinical decision-making.     

Calciphylaxis – a topical overview

'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis.     

Carriage of Haemophilus influenzae and Streptococcus pneumoniae in healthy Chinese and Vietnamese children in Hong Kong

Nasopharyngeal carriage of Haemophilus influenzae and Streptococcus pneumoniae was studied in 621 healthy Chinese children and 300 healthy Vietnamese children aged from 2 months to 5 years in Hong Kong. The carriage rate of H, influenzae type b in Vietnamese children was 1.3% (CI 0.04-2.63%); it was zero in Chinese. The carriage rate of non-typable H. influenzae was 5.8% (CI 1.4-7.6%) in Chinese and 65.4% (CI 58.9-69.8%) in Vietnamese. The carriage rates of S. pneumoniae were 10.8% (CI 8.3-13.2%) and 55.7% (CI 50.1-61.3%) in Chinese and Vietnamese children, respectively. Univariate and multivariate logistic regression analyses were performed to search for factors associated with differences in carriage rates of both H. influenzae and S. pneumoniae between Chinese and Vietnamese children. Although older age, smaller living area and parental smoking were associated with higher carriage rates, these could not explain the remarkably low carriage rates of both bacteria in Chinese children.     

DNA testing for fragile X syndrome in schools for learning difficulties

Fragile X syndrome is the most common inherited cause of mental retardation. Early diagnosis is important not only for appropriate management of individuals but also to identify carriers who are unaware of their high risk of having an affected child. The disorder is associated with a cytogenetically visible fragile site (FRAXA) at Xq27.3, caused by amplification of a (CGG)n repeat sequence within the gene at this locus designated FMR1. Clinical and molecular studies have been undertaken to screen for fragile X syndrome in 154 children with moderate and severe learning difficulties of previously unknown origin. Southern blot analysis of peripheral blood showed the characteristic abnormally large (CGG)n repeat sequence associated with fragile X syndrome in four of the 154 children. The findings were confirmed by cytogenetic observation of the fragile site and by further molecular studies. The families of the affected children were offered genetic counselling and DNA tests to determine their carrier status. These findings show that there are still unrecognised cases of fragile X syndrome. Given the difficulty of making a clinical diagnosis and the implications for families when the diagnosis is missed, screening in high risk populations may be justified. The issues involved in screening all children in special schools for fragile X syndrome are discussed.