Penetration and distribution of three lipophilic probes in vitro in human skin focusing on the hair follicle.

Fluorescent model substances of increasing lipophilicity (Oregon Green) 488, Bodipy, FL C5 and Bodipy 564/570 C5) were selected to enable the visualization in the skin using confocal laser scanning microscopy. After measuring the penetration for 18 h, the nonfixed human scalp skin was imaged from the bottom parallel to the stratum corneum and in a cross-section view perpendicular to the skin surface. The images were evaluated by calculating relative accumulation values for different penetrants. The studies indicate that the penetrated amount is highest for Bodipy FL C5 (medium lipophilicity) and lowest for Bodipy 564/570 C5 (high lipophilicity) whereas Bodipy 564/570 C5 (high lipophilicity) reveals the highest relative accumulation in parts of the hair follicle compared to Oregon Green 488 (low lipophilicity). The addition of 30% (v/v) ethanol to the donor phase of substance with a low lipophilicity increases the follicular delivery. From our results we conclude that delivery to the hair follicle can be improved by increasing the drugs lipophilicity and optimizing the composition of the donor phase. However, no conclusion can be drawn about the actual route of transport to the hair follicle.     

Vibration exposure and conditioning lesion effect in nerves: an experimental study in rats.

The effects of controlled vibrations of defined frequency (80 Hz), acceleration (32 m/s2 root mean square), and duration (5 hours daily, 2 or 5 days) induced to the hind limb of rats on the regeneration potential in the sciatic nerve after a test crush lesion were determined. Exposure to vibration induced a marked and significant increase in outgrowth length of axons from the crush injury as evaluated after 3 and 6 days with the pinch reflex test. This effect was still observed 1 month but not 3 months after exposure to vibration. Even such a short duration of vibration exposure as 2 days induced an increased length of outgrowth. Such a conditioning effect may be due to local changes in the environment of the axons or to changes in the nerve cell bodies in the dorsal root ganglion. The results indicate that an alarm reaction exists in the nerve at a time point where no structural changes are observed in the nerve. By inducing such a conditioning lesion to nerve tissue, vibration represents a trauma corresponding to a crush lesion or transection of the nerve.     

Efficacy and safety of axillary brachial plexus block for operations on the hand.

An axillary brachial plexus nerve block by a transarterial approach is commonly used to achieve regional anaesthesia for hand surgery. We designed a retrospective study to evaluate efficacy and safety of the technique for acute and elective operations. Anaesthetic records of 189 of all 5520 patients (1996-2000) who had axillary brachial plexus blocks for hand surgery were reviewed, and results compared with complications recorded in the anaesthetic register and in the hand surgery records. Successful axillary block was achieved in 5128/5520 (93%) of patients, according to anaesthetic charts, and primarily in 157/189 (83%), and after supplementation in 171/189 (90%), according to anaesthetic records. Four patients had a toxic drug reaction or axillary haematoma with a transient neurological deficit. Medical complications were recorded in the anaesthetic register in less than 0.7% of axillary brachial plexus procedures. Axillary brachial plexus block by a transarterial approach is effective and safe in hand surgery.     

The pathophysiology of nerve compression.

The basic pathophysiology of an acute and chronic nerve compression lesion is complex. Compression of a peripheral nerve induces marked changes in intraneural microcirculation and nerve fiber structure, impairment of axonal transport, and alterations in vascular permeability, with edema formation and deterioration of nerve function. The peripheral nerves of subjects with underlying neuropathies are more susceptible to compression injury.     

Reconstruction of ligaments with expanded polytetrafluoroethylene. An experimental study in rabbits.

The medial collateral ligaments in the knee joints of 15 rabbits were replaced with expanded polytetrafluoroethylene (E-PTFE). The joints were not immobilised postoperatively, and their structure and function were evaluated after 12 months. Range of motion was equal in all groups. Stability of the knee joints and breaking strength of the ligaments were similar in the group in which the ligament had been reconstructed and in the sham operated control group (n = 8). The group in which the ligament had been severed and left to heal by formation of scar tissue (n = 7) had significantly reduced joint stability and the breaking strength of the medial collateral ligament was significantly less. The E-PTFE ligaments were well incorporated into the surrounding tissues. There were no adverse tissue reactions and the articular cartilage looked normal both macroscopically and microscopically. These results indicate that E-PTFE might be a useful substitute for damaged ligaments, at least in smaller joints like metacarpophalangeal and interphalangeal joints.     

Ultrastructure of malignant histiocytoma arising in the acromion.

The ultrastructural features of a malignant histiocytoma of the acromial process of the scapula were studied. Material was obtained from two surgical biopsy specimens and an amputation specimen from the tumor. Cells possessing characteristics of histiocytes, fibroblasts, xanthoma cells, and multinucleated giant cells were present throughout the tumor. Smaller numbers of undifferentiated cells and lymphocytes were also observed. Intimate cytoplasmic interdigitations between adjacent tumor cells were found, and instances of degenerating intracytoplasmic cells, possibly representing phagocytosis, were observed. Specimens stained with periodic acid-Schiff reagent with and without exposure to diastase, examined by light microscopy, showed that numerous cells contained phagocytized material consisting of degenerating cells rather than cytoplasmic glycogen. Intraumor lymphocytes apparently represented an inflammatory reaction to the tumor. The tumor giant cells and xanthoma cells were probably modified histiocytes. Results of the study were compared with previous reports of ultrastructural studies of malignant histiocytoma of soft tissues. Fundamental similarities between such studies and this one suggested that the progenitor cell is a histiocyte, whether arising in bone or in soft tissues, and that the progenitor cell is capable of differentiation in both histiocytic and fibroblastic directions.     

Exercise but not Prostanoids Enhance Levels of Vascular Endothelial Growth Factor and other Proliferative Agents in Human Skeletal Muscle Interstitium

In the present study we examined whether exercise and prostanoids have an effect on the muscle interstitial concentration of vascular endothelial growth factor (VEGF) and on the proliferative effect of muscle interstitial fluid. Dialysate from resting and exercising human skeletal muscle, obtained either during control conditions or during cyclooxygenase inhibition, was examined for its content of VEGF and for its effect on endothelial cell proliferation. Microdialysis probes with high (960 kDa) and low (5 kDa) molecular-mass cut-off membranes were placed in the vastus lateralis muscle of healthy young males. The subjects performed one-legged knee extensions (20 W). The concentration of VEGF in the 960 kDa dialysate was greater (   P < 0.05  ) during exercise compared to at rest (67 ± 28 vs. 230 ± 22 pg ml⁻¹). The rate of endothelial cell proliferation was 2.7-fold higher (   P < 0.05  ) with the 960 kDa dialysate from resting muscle than with perfusate and was 5.8-fold higher (   P < 0.05  ) than the perfusate value with dialysate from exercising muscle. VEGF was not enhanced with exercise in the 5 kDa dialysate, yet the exercise dialysate induced a 1.9-fold higher (   P < 0.05  ) proliferation than the resting dialysate. Cyclooxygenase inhibition did not affect the VEGF concentration or the proliferating effect of the dialysates (   P > 0.05  ). This study demonstrates for the first time that VEGF is present in the interstitium of human skeletal muscle and that exercise enhances the interstitial concentration of VEGF and of other, as yet unidentified, angiogenic compounds. Products of cyclooxygenase do not appear to have an effect on the release of VEGF or other proliferative agents in human skeletal muscle.     

Fibrocartilaginous mesenchymoma with low-grade malignancy

In a review of cases of fibrous cartilaginous dysplasia of bone, five of fibrocartilaginous lesions were found to be different in clinical behavior and radiographic and morphologic features from the others. We have named these previously undescribed tumors fibrocartilaginous mesenchymomas with low-grade malignancy in the fibrous elements.Dr. Bertoni is a visiting surgical pathologist from the Servizio di Anatomia ed Istologia Patologica, Bologna, Italy