综合性医院手术科室分配机制技术框架探讨

卫生系统的改革依赖于包括分配机制在内的适宜的内部管理运行机制的催化。作者在分析综合性医院政策限度和技术限度基础上，构想手术科室分配机制的技术框架。引入“综合系数”、“人时”单位、“收入弹性系数”等概念，建立定量考核指标体系，确定指标的期望值以及各类手术之间的换算比例。分配机制紧紧依托卫生系统现有的宏观环境，机制的诱导趋势与卫生政策的导向一致。由于最重要的指标－－期望月均手术量的核定是建立在现有人员构成基础上，故可以避免按床位定编将产生的人员分流组合所带来的振荡，为医院重新调配资源创造灵活的空间，同时可确保各科相互之间的比较具有水平公平性。     

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     

Microscopic magnetic resonance elastography (microMRE).

Magnetic resonance elastography (MRE) was extended to the microscopic scale to image low-frequency acoustic shear waves (typically less than 1 kHz) in soft gels and soft biological tissues with high spatial resolution (34 micromx34 micromx500 microm). Microscopic MRE (microMRE) was applied to agarose gel phantoms, frog oocytes, and tissue-engineered adipogenic and osteogenic constructs. Analysis of the low-amplitude shear wave pattern in the samples allowed the material stiffness and viscous loss properties (complex shear stiffness) to be identified with high spatial resolution. microMRE experiments were conducted at 11.74 T in a 56-mm vertical bore magnet with a 10 mm diameterx75 mm length cylindrical space available for the elastography imaging system. The acoustic signals were generated at 550-585 Hz using a piezoelectric transducer and high capacitive loading amplifier. Shear wave motion was applied in synchrony with the MR pulse sequence. The field of view (FOV) ranged from 4 to 14 mm for a typical slice thickness of 0.5 mm. Increasing the agarose gel concentration resulted in an increase in shear elasticity and shear viscosity. Shear wave motion propagated through the frog oocyte nucleus, enabling the measurement of its shear stiffness, and in vitro shear wave images displayed contrast between adipogenic and osteogenic tissue-engineered constructs. Further development of microMRE should enable its use in characterizing stiffer materials (e.g., polymers, composites, articular cartilage) and assessing with high resolution the mechanical properties of developing tissues.     

Non-linear modelling of breast tissue.

Previous approaches to modelling the large deformation of breast tissue, as occurs, e.g. in imaging using magnetic resonance imaging or mammography, include using linear elasticity and pseudo-non-linear elasticity, in which case the non-linear deformation is approximated by a series of small linear isotropic deformations, with the (constant) Young's modulus of each linear deformation an exponential function of the total non-linear strain. In this paper, these two approaches are compared to the solution of the full non-linear elastic problem for tissue with an exponential relationship between stress and strain. Having formulated each model and related the coefficients between the models, numerical simulations are performed on a block of incompressible material. These demonstrate that the simpler models may not be appropriate even in the case of modelling deformations of the human breast under gravity.     

A piconewton force transducer and its application to measurement of the bending stiffness of phospholipid membranes

The bending stiffness of a phospholipid bilayer (kc) was measured by forming thin bilayer cylinders (tethers) from giant phospholipid vesicles. Based on the balance of forces, the tether force was expeeted to be proportional to the square root of the membrane tension, with a constant of proportionality containingk>c. The membrane tension was controlled via the aspiration pressure in a micropipette used to hold the vesicle. The force on the tether was generated by an electromagnet acting on a paramagnetic bead attached to the vesicle surface. The magnitude of the force was determined from measurements on the magnet current which was adjusted to maintain the position of the bead. Measurements were performed on vesicles composed of stearoyl-oleoyl-phosphatidylcholine plus 5% (by mole) biotinylated phosphatidylethanolamine to mediate adhesion to streptavidin-coated beads. From each vesicle, tethers were formed repeatedly at different values of the membrane tension. The expected relationship between membrane tension and tether force was observed. The mean value ofkc for 10 different vesicles was 1.17×10⁻¹⁹ J (SD=0.08×10⁻¹⁹ J). The precision of these data demonstrates the reliability of this approach, which avoids uncertainties of interpretation and measurement that may be associated with other methods for determiningkc.     

Computerized evaluation of skin stiffening in scleroderma

Modern non-invasive biometrological methods have proven to be helpful in monitoring some skin disorders. The present study was designed to evaluate the mechanical properties of skin in systemic scleroderma. The Cutometer SM 474 was used to measure the rheological properties of the skin in 33 patients suffering from scleroderma. The most prominent abnormality consisted in a marked reduction in skin extensibility. Changes occurring in time objectivate the evolution of the disease. Measuring the mechanical properties of skin in patients with scleroderma may be useful in monitoring the disease and its treatment.     

Influence of age and regional differences on skin elasticity as measured by the Cutometer®

Background/aim: Aging of skin is accompanied by decrease of skin elasticity. Using the noninvasive suction device Cutometer^®, we evaluated the age and regional body differences of the viscoelastic properties of human skin. The objectives of this study were to evaluate the correlation between age and the biomechanical parameters and the regional skin variations.
Methods: A total of 96 healthy women aged 20–75 years were included in this study. The biomechanical properties of the skin were measured by using the Cutometer^®. Measurements were made on the face, upper arm and back.
Results: The age of subjects showed significant positive correlation with R4 and R6, and negative correlation with R2, R5 and R7. The face showed bigger changes of elastic properties than the arm and the back. Especially, the R7 of face was most significantly decreased with aging. We could estimate the so-called 'skin age' by using a correlation equation for this parameter.
Conclusion: The viscoelastic properties were significantly influenced by aging. Also, significant regional variations in the viscoelastic properties were observed. Skin elasticity measurement is useful for the quantitative evaluation of age-related changes.     

Effects of price, ‘openness’ of the economy and magnitude of the alternative reinforcer on responding for caffeinated coffee

Consumption of a commodity is influenced by various factors. This experiment examined three factors: unit price, ‘openness’ of the economy, and magnitude of an alternative reinforcer. Subjects earned caffeinated coffee and money by responding on concurrent random-ratio (RR) schedules. Coffee price was varied by changing the coffee schedule from RR 1·3 to RR 16, while holding the money schedule constant (RR4). Openness of the economy was varied by changing the amount of unearned coffee provided during a 2-h post-task period (0, 1·5 or 3 free cups). The magnitude of the alternative reinforcer was varied by allowing subjects to earn an average of $2·00 or $6·00 for responding on the money schedule. Number of responses for coffee and amount of coffee earned varied inversely with the openness of the economy, but were unaffected by the amount of money available. Analysing the demand for coffee as a function of coffee price revealed that coffee was a less elastic commodity when the economy was closed than when it was more open. Within the range of parameters tested here, price of caffeinated coffee and openness of the economy strongly affected responding in humans, whereas the magnitude of an alternative monetary reinforcer had only limited effects.     

Series-elastic properties of strips of smooth muscle from pig urinary bladder

The series elasticity of strips of smooth muscle from pig urinary bladder was investigated by means of a series of computerised quick-release and quick-stretch measurements with and without stimulation of the muscle, and at different shortenings and force levels. The results cannot be interpreted in terms of a discrete passive series-elastic element. They can, however, be interpreted in terms of the sliding-filaments model for contracting muscle.     

Lipoplasty of the torso in patients over fifty

This article describes the author's experience in performing lipoplasty in patients over 50 years of age. Historically, emphasis was placed on selection of patients for this procedure who were under age 40 years. However, the author's experience with 20 patients over 50 indicates extremely high patient satisfaction. Subsequent skin excision was required in only 10% of the patients.The author concludes that many patients over 50 have good skin elasticity and represent satisfactory candidates for lipoplasty. Age alone should not exclude these patients.