Development of Acoustic Instruments for Diagnosis and Management of Medical Conditions

Computerized analysis of lung sounds can play a very important role in management of patients with a variety of medical conditions, particularly those who are seriously ill. While single-channel devices can play an important role in making auscultation more objective, multi-channel instruments greatly improve the efficiency of data collection. This has a particular advantage in the rapid assessments of patients who are in acute distress from cardiopulmonary conditions. As noted, it has the distinct advantage of being noninvasive. This is a particular advantage in the case of children and pregnant women. A number of other groups are currently working with multichannel devices, but have not yet reported their findings. The future will likely see improved acoustic instruments useful in diagnosis and management of medical conditions     

Assessment of bog-body tissue preservation by pyrolysis-gas chromatography/mass spectrometry

Flash pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) was used to assess the quality and mechanism of protein preservation in the tissue of Iron Age bog bodies from Lindow, UK, and south-eastern Drenthe, The Netherlands. Abundant pyrolysis products of the fresh skin tissue, including 2,5-diketopiperazines of Pro-Gly, Pro-Ala, Pro-Val, Pro-Pro and Hyp, were readily assigned to specific amino acid or dipeptide moieties. Comparison of the pyrolysates of the bog-body tissues with that of modern samples revealed qualitative similarities suggesting good preservation of the collagen and non-collagenous proteins in the ancient tissues. Examination of the pyrolysates of samples of fresh calf skin, which had been treated with various vegetable tanning agents, clearly revealed markers of non-hydrolysable tannins including 1,2-benzenediol, 1,3-benzenediol and 1,2,3-benzenetriol, although chromatographic quality inevitably diminished with increasing functionalization of the compounds. Such markers were not detected in the pyrolysates of the bog-body tissues. Instead 4-isopropenylphenol, a characteristic pyrolysis product of Sphagnum moss, was detected in both solvent-extracted and base-treated samples of tissue. The presence of 4-isopropenylphenol in the pyrolysates of the bog-body tissues provides evidence that their preservation involves reactions of amino acids with sphagnum acid, and possibly other agents derived from the peat. The study constitutes the first chemical characterization of the pyrolysis products of modern and ancient collagen.     

Relating matrix metalloproteinase structure to function: why the "hemopexin" domain?

Matrix metalloproteinases are thought to be key players in the remodelling activity of cells associated with both physiological and pathological processes. They share a relatively conserved structure with a number of identifiable modules linked to their specific functions. The structure of the individual domains of a number of matrix metalloproteinases have now been elucidated. Here we review these data in the light of complementary studies on the behaviour of these enzymes in biological systems. In particular we focus on the C-terminal hemopexin-like domain which has intriguingly specific roles in individual matrix metalloproteinases.     

Extrahepatic metabolism of 4-methylumbelliferone and lidocaine in the anhepatic rabbit

OBJECTIVE: The initially well-fixed implants of total hip replacement (THR) are in the long-term subject to aseptic loosening. Many cytokines can contribute to osteolysis due to osteoclast recruitment and/or activation. However, in this respect tumor necrosis factor-alpha (TNF-alpha) plays a pivotal role, because it upregulates interleukin-1 and 6 and granulocyte-macrophage colony stimulating factor. The aim of this study was to assess the eventual presence, cellular localization and extent of expression of TNF-alpha in the synovial-like membrane at the implant or at the cement to bone interface compared to control synovial membrane. METHODS: Twenty samples from the synovial-like membrane of the periprosthetic tissues were compared to control samples. TNF-alpha containing cells were visualized using an avidin-biotin-peroxidase complex (ABC) method and analyzed by light microscopy, double labelling and image analysis. RESULTS: TNF-alpha was found in the periprosthetic tissues in fibroblasts and vascular endothelial cells, but mainly in the macrophages was it found to coincide with areas containing implant-derived debris. TNF-alpha containing cells were more numerous in the synovial-like membrane in the interface tissue from the proximal stem area (2816 +/- 318 cells) than in the control synovial membrane (565 +/- 93 cells, p < 0.01). Interestingly, similarly high TNF-alpha expression (3452 +/- 582 cells) was also seen in the synovial-like membrane of the pseudocapsule. CONCLUSION: These findings suggest that the foreign body-type host reaction caused by THR is characterized by the high expression of TNF-alpha. Because such expression occurred in the interface tissue between the implant and surrounding bone, TNF-alpha, due to its pivotal direct and indirect role in the activation and recruitment of osteoclasts, may contribute to periprosthetic osteolysis and to the loosening of THR.     

Comment. Remarks on the LUC public key system

The authors of [Remarks on the LUC public key system, see ibid., vol. 30, p. 123, 1994] consider the Lucas function on which the public cryptosystem LUC proposed by Smith and Lennon [1993] is based. For a finite field G with m∈G, the Lucas function V_n(m) is defined by the second order linear recurrence relation V_n(m)=mV_n-1(m)-V_n-2(m) where V_o (m)=2, V₁(m)=m. The characteristic polynomial f of the Lucas function is f(x)=x²-mx+1, and V_x(m)=α ^x+α^-x where α is a root of f. We now consider some of the results of and give concise proofs     

Meeting a person with AIDS in the classroom: an evaluation

Meeting a person with AIDS in the classroom was evaluated to determine if it had an impact on students' perceived susceptibility to HIV infection and attitudes toward persons with AIDS. The meeting was incorporated into the Grade 9 AIDS education program of a school district in Nova Scotia. Four schools participated in this study. Two schools were randomly assigned to the treatment group, which met the person with AIDS, and the remaining two schools formed the comparison group. Measures of the two attitudinal variables were collected using a self-report questionnaire that was administered both prior to and two weeks after the educational intervention. Meeting a person with AIDS in the classroom had no measurable impact on students perceived susceptibility to HIV infection nor on their attitudes toward persons with AIDS. Suggestions for using the educational intervention more effectively and for further research are made.     

Modal convection and its effect on the stability of EDM wires

Recently, it has been shown that EDM wires undergo thermal buckling at low axial transport speeds and a series of transport instabilities at high axial transport speeds. Hence, only intermediate speeds ensure the straight wire configuration, which is needed for high-accuracy cutting. These conclusions are based on the assumption that the convective heat transfer coefficient remains piecewise constant along the length of the wire. However, a recent study on convection from a vibrating, flexible body shows that the convection coefficient becomes modal. The present study re-examines the wire stability problem with this modal effect in mind. It is shown that at low axial transport speeds, the straight wire configuration may be stable. Its stability hinges on vibration—large amplitude motion implies increased convection and increased stability from thermal buckling. At high transport speeds, the system still undergoes the reported transport instabilities. This work shows that the well-defined intermediate speed range is not so well-defined in the presence of wire vibrations.