Rosin components identified in diapers

As part of the investigation of sources of exposure of rosin allergens, disposable diapers (napkins) common on the Swedish market were analyzed, using gas chromatography, to detect the main rosin compounds. Rosin components were detected in all diapers, the highest amounts in those from the 2 major producers. In these diapers, more rosin was found in the top layer, which is in close contact with the skin, than in the fluff. Despite the possibly minimal risk of induction of sensitization to rosin allergens in diapers, there is a real risk of elicitation of dermatitis in sensitive individuals, especially since penetration is enhanced by occlusion and irritation. Such material is not only used for infant diapers, but also for adult incontinence products and feminine hygiene products.     

In vivo knee loading characteristics during activities of daily living as measured by an instrumented total knee replacement

We examined the relationship between activity, peak load, medial to lateral load distribution, and flexion angle at peak load for activities of daily living. An instrumented knee prosthesis was used to measure knee joint force simultaneously with motion capture during walking, chair sit to stand and stand to sit, stair ascending and descending, squatting from a standing position, and golf swings. The maximum total compressive load at the knee was highest during stair ascending and descending and lowest during rising from a chair. Maximum total compressive load occurred at substantially different flexion angles ranging from 8.5° during walking to 91.8° during squatting. For all activities, total compressive load exceeded 2 times body weight, and for most activities 2.5 times body weight. Most activities placed a greater load on the medial compartment than the lateral compartment. Activities were grouped into three categories: high cycle loading (walk), high load (stair ascent, descent, and golf), and high flexion angle (chair sit to stand/stand to sit, and squat). The results demonstrate that the forces and motion sustained by the knee are highly activity‐dependent and that the unique loading characteristics for specific activities should be considered for the design of functional and robust total knee replacements, as well as for rehabilitation programs for patients with knee osteoarthritis or following total knee arthroplasty. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1167–1172, 2008     

Sensitivity of knee replacement contact calculations to kinematic measurement errors

The ability to measure in vivo knee kinematics accurately makes it tempting to calculate in vivo contact forces, pressures, and areas directly from kinematic data. However, the sensitivity of contact calculations to kinematic measurement errors has not been adequately investigated. To address this issue, we developed a series of sensitivity analyses derived from a validated in vivo computational simulation of gait. The simulation used an elastic foundation contact model to reproduce in vivo contact force, center of pressure, and fluoroscopic motion data collected from an instrumented knee replacement. Treating each degree of freedom (DOF) in the simulation as motion controlled, we first quantified how errors in measured relative pose of the implant components affected contact calculations. Pose variations of ±0.1 mm or degree over the entire gait cycle changed maximum contact force, pressure, and area by 204, 100, and 117%, respectively. Larger variations of ±0.5 mm or degree changed these same quantities by 1157, 108, and 578%, respectively. In both cases, the largest sensitivities were to errors in superior‐inferior translation and varus‐valgus rotation, with loss of contact occurring on one or both sides. We then quantified how switching the sensitive DOFs from motion to load control affected the sensitivity results. Pose variations of ±0.5 mm or degree in the remaining DOFs changed maximum contact quantities by at most 3%. These results suggest that accuracy on the order of microns and milliradians is needed to estimate contact forces, pressures, and areas directly from in vivo kinematic measurements, and that use of load rather than motion control for the sensitive DOFs may improve the accuracy of in vivo contact calculations. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1173–1179, 2008     

The incidence of allergy to propolis in 605 consecutive patients patch tested in Prague

605 consecutive patients were patch tested with the standard CDRG test series and with a 10% alcoholic solution of propolis. Positive allergic reactions to propolis were observed in 25 patients (4.2%); thirteen of them exhibited a simultaneous positive patch test to balsam of Peru. In view of the relatively high incidence of allergic reactions and the appearance of pseudo-cross-sensitivity to another common allergen, balsam of Peru, propolis should not be used in topical medicaments or as a component of cosmetic preparations.     

Experimentally induced variations in the dark adaptation functions of a severe strabismic amblyope

Dark adaptation curves were determined for an amblyopic and a normal control subject following a variety of preadaptation conditions. Sizable between-eye differences were found in the dark adaptation functions of only the amblyope; the magnitude of such differences varied with this subject's distance from the light preadapting screen and with the effective size of his pupils during the light preadaptation period. Marked differences were also found between the dark adaptation functions of both eyes of the amblyopic subject and those of the normal subject. The preadaptation-dependent changes in the dark adaptation function of the amblyopic subject are hypothesized to result from anomalies of amblyopic eye light adaptation which are referable to disturbances of retinal receptor alignmentA part of this research was supported by the U.S. National Eye Institute of N.I.H. Grant EY00800 to the second author. We thank Paul E. Grattan, O.D., Waterford, N.Y. and Steven Sills, M.D., Albany, N.Y. for their expert clinical consultations. The authors also gratefully acknowledge the assistance of Professor Fred Billmeyer and the members of the Rensselaer Color Measurement Laboratory of Rensselaer Polytechnic Institute in determining filter transmittances.A portion of this work was submitted in partial fulfillment of the requirements for the M.S. degree in Psychology for the first author at Rensselaer Polytechnic Institute.Psychology Department, Rensselaer Polytechnic Institute, Troy, N.Y., 12180, U.S.A.     

Elbow eruptions in nickel and chromate dermatitis

In 7 patients with nickel or chromate allergy and dyshidrotic hand eczema, we observed symmetric hyperkeratotic lesions on the elbows which ran a similar course to the hand dermatitis.
Histopathological examinations show findings suggestive of lichen simplex chronicus and subacute-chronic dermatitis, but exclude psoriasis.
We conclude that these elbow lesions are a characteristic of systemic allergic contact dermatitis.     

Allergic contact dermatitis and conjunctivitis to corticosteroids

This is a report of two patients suspected of having allergic dermato-conjunctivitis due to corticosteroids. Both were tested with the constituents of the ointments they were using, that is, corticosteroids, antibacterial agents, preservatives, and other active ingredients of the ointment bases. Both patients showed positive allergic patch test reactions to the respective corticosteroid betamethasone valerate, and one to hydrocortisone, neomycin, and a rubber additive. The importance of routine patch testing in ophthalmic practice to detect sensitizers in cases of allergy is mentioned. Hydrocortisone (25%) in petrolatum is recommended for patch testing.     

Biophysical behaviour of the infant Meibomian lipid layer

Infants have been known occasionally to stare without blinking for almost a minute. This puts great demands on the stability of their tear-film. To verify the stability of infant tears, we performed biophysical experiments on Meibomian gland secretion, which forms the outermost layer of the tear-film. The secretion was taken from infants belonging to one of three age-groups (1.5 years, 4–5 years, 7–10 years). Underin vitro conditions we determined the surface pressure and the surface potential of the film by spreading the secretion over a water surface and subsequently compressing and decompressing it. Sufficient amounts of Meibomian gland secretion were expressed in all age-groups. The surface pressure and the surface potential of the tears in infants corresponded to those in healthy adults. It was also found that the younger the patient was, the better was the consistency of the surface potential under repeated periods of compression and expansion. In comparison with the secretion of healthy adults, the infant Meibomian gland secretion showed better biophysical characteristics and a correspondingly higher stability in the tear-film.Abbreviation MGS Meibomian gland secretion