Living microlens arrays

Both individual cells and sheets of cells exert traction forces on the substrate and these forces have been investigated using a wide range of methods. Here we compare the mechanical properties of fibroblasts and epithelial cells using a novel surface geometry. Living cells are added to a thin film of polystyrene [PS] attached to a substrate of crosslinked poly(dimethyl siloxane) [PDMS] microwells. The contractile nature of the cells attached to the surface and the compliance of the PDMS surface geometry allows the PS thin film to buckle, forming arrays of convex microlenses. The resulting curvature of the microlenses allows us to determine the applied strain of growing cell sheets. We report that a monolayer of epithelial cells exerts more stress on the substrate than fibroblasts and attribute this to the collective behavior of the epithelium. By subsequently adding different chemical triggers to the system, the contractile nature of the cells changes, thus modifying the focal length of the microlenses. Together, these findings demonstrate the importance of studying the mechanics of cell sheets and also introduce a new design paradigm for advanced materials, offering great promise for a range of applications.     

Experiences with the identification of small rodents

Own experiences with the identification of mice and rats using ear tags, ear punching, toe clipping (for newborns only) and ear tattooing are given and compared with methods presented in literature. By far, ear tattooing by the newly developed pincers is the most suitable method for marking adult rodents for life. Tattooing is easy to apply, easy to read and not harmful to the animals. For newborn pups on day 4 p. p., the s. c. injection of India ink into the palm of paw is recommended.     

Experiences with the Coulter Counter in Bacteriology

Viable and killed suspensions of Staphylococcus aureus SM, Escherichia coli, and Serratia marcescens, as well as polystyrene spheres, 0.81 and 2.85 μ in diameter, were counted electronically with a model A Coulter Counter. Simultaneous counts by standard bacteriological methods and microscopy were done for purposes of control and comparison with the data from the Coulter Counter. Results indicated: (i) electrical characteristics of different bacterial populations are different; (ii) electronic counts were consistent for species used; (iii) live S. aureus exhibits a denser pattern of thick bright pulses on the cathode-ray tube than does live E. coli; (iv) killed bacteria resemble inert particles in pulse pattern; and (v) some viable bacteria do not react independently of current flow, as do inert particles and killed bacteria.     

Experiences with cortisone given orally

The advantages of the oral administration of cortisone, when compared with cortisone given intramuscularly, include the more rapid appearance of therapeutic effects, which is of importance in the therapy of acute disease, and the faster dissipation of effects when the hormone is discontinued, which is of value when dangerous reactions occur. Oral dose schedules depend upon the degree of urgency or chronicity of the treated disease. In acute diseases the therapeutic results, in general, were disappointing. Cortisone may be of greater value in the long-term maintenance treatment of certain chronic diseases. By long-term therapy the authors mean practically continuous treatment until either the disease goes into spontaneous remission or undesirable effects of the drug require cessation of treatment. Critical selection of patients and constant supervision of therapy are vital to the successful administration of cortisone. Even with these precautions, however, the therapeutic use of cortisone must be regarded as experimental until the passage of time permits better appraisal of harmful effects.     

Experiences with the tensor fascia lata flap.

Our experience with 60 TFL flaps is reviewed. The anatomy and the arcs of rotation of this flap are described. Our clinical experience--particularly in reconstruction of the groin and abdominal wall, and in free flap transfers--has been detailed, including the use of a free osteomyocutaneous sensory TFL flap for reconstruction of the heel.     

Clinical Experiences with Assisted Circulation

Of primary importance in the clinical application of mechanical support for the failing circulation are the selection of patients and definition of criteria for assessing the therapeutic results. Experimental and clinical observations suggest that serial measurements of arteriovenous oxygen difference are a reliable rough measurement of the adequacy of the existing cardiac output to meet the oxygen requirements of the tissues. Patients with a decreasing cardiac output may profit from assisted circulation. Thirteen such patients are presented, all of whom were in intractable heart failure. Seven “medical” patients underwent common femoral vein-to-artery perfusion with an oxygenator for an average of 135 minutes. Of these, one patient who had already had two cardiac arrests died, six patients showed striking clinical and biochemical improvement for hours to days, and two patients were discharged from the hospital. Of particular interest were five in whom the indication for assisted circulation was irreversible cardiac arrest. Three patients were resuscitated, and one, who had neurological signs usually accepted as those of anoxic cerebral damage for 45 minutes, recovered completely.     

Experiences with development of morphological typology of the face

On base of the component analysis of facial dimensions the original diagnostic model of definition of a morphological facial type in Russian males and females is developed. The first typological characteristic feature describes the variability of general face size, allocating extreme micro- and macrotypes. The second one describes the face shape as a ratio of frontal and mandibular parts. On poles of variability it demonstrates a type with massive frontal face part and rather reduced mandibular one, and a contrast type with a massive mandibular part at relative gracile frontal face part. Central position in this model is occupied by variants with equally proportional development of the top and bottom face parts. On the basis of seven traditional anthropometric facial dimensions the place of any individual in terms of face size and form can be easily found in the suggested model. The chosen contrast variants of the face form are comparable to the appropriate characteristics of cerebral and digestive Sigaud types. The offered morphotypology allows to estimate accurately individual and group features in the face form. The methods of multivariate analysis reveal steady connection between somatotypes and features of a facial structure. Though the level of correlation does not exceed 0.3-0.4 of correlation coefficients, it is statistically significant at the highest degree of probability. The basic direction of habitus variability in men is observed at general face size, in women at face shape.