Amphiphilic nanoparticles generate curvature in lipid membranes and shape liposome-liposome interfaces.

We show by molecular dynamics that amphiphilic Au nanoparticles (NP) with a diameter of 4 nm generate curvature in phosphatidylcholine lipid membranes. NPs generate negative curvature when they adsorb on the membrane surface but, as they get spontaneously and progressively embedded into the membrane core, the curvature turns positive. As membrane embedding is kinetically slow, both configurations can be observed by Cryo-EM. NP-induced curvature explains the peculiar structure of liposome-liposome interfaces in presence of NPs.

Transpedicular decancellation osteotomy in the treatment of peridural fibrosis.

From 1992 to 1997 a series of 12 multiply operated (averaging 2.5 previous operations) patients with recurrent peridural fibrosis and postlaminectomy kyphosis underwent surgery at our clinic. The surgery was designed to restore the physiological lordosis and relax tethered cord and epidural veins by transpedicular decancellation osteotomy at a vertebra other than the vertebra with peridural fibrosis. This paper presents the long-term functional outcome of these 12 patients. Clinical assessments were conducted pre-operatively and at 3-month intervals postoperatively and included X-ray assessment and evaluation of the patients' functional status by Oswestry Disability Index (ODI) and of pain by visual analogue scale (pain VAS). All symptoms and the pain due to peridural fibrosis disappeared in the early postoperative period. Patients had tower disability and pain scores at their early and long-term follow-ups (follow-up period 24-74 months, mean 36.3 months). For patients with failed medical therapy for peridural fibrosis accompanied by lumbar kyphosis or hypolordosis, transpedicular decancellation osteotomy should be the surgical treatment of choice.

Surgical technique and functional results of irreparable cuff tears reconstructed with the long head of the biceps tendon.

The purpose of the study was to evaluate the results obtained from patients who were treated with open surgical technique using the long head of the biceps tendon for irreparable tears of the rotator cuff tendons. Between May 1992 and January 1997, 14 patients underwent rotator cuff reconstruction of irreparable tears at our clinic. These patients were evaluated before and after a minimum follow-up of 26 months (mean: 40.2 months) following surgery with the Constant's functional score. The long heads of the biceps tendons were found to be hypertrophied in all 14 shoulders and in 10 of them they were also subluxated. After re-seating the surgically enlarged biceps tendon onto the center of the uncovered head region, the biceps tendon to cuff tendon repair and the biceps tenodesis were done in all shoulders. The mean functional Constant's score before surgery was 46.7 points (poor) and the mean postoperative score at the final follow-up was 75.35 points (good). Satisfactory results were achieved in 85.7% of the patients. These results suggest that this surgical technique can be used to attain a painless and functional shoulder after irreparable cuff tear reconstruction.

The effects of age, height and gender on the somatosensory evoked potentials in man.

Somatosensory evoked potentials (SEPs) reflect the activity of somatosensory pathways mediated through the dorsal columns of the spinal cord and the specific somatosensory cortex. In this study we aimed to demonstrate the effects of physiologic parameters such as height, age and gender on N9, N13, N20 SEP components and the central conduction time (CCT) to median nerve stimulation in Turkish population. The results revealed a statistically significant correlation between height, gender and SEP latencies (p < 0.05 and p < 0.0005 respectively) whereas no significant age related changes was found in SEPs. In all groups CCT was not influenced by these parameters.

The effect of conventional transcutaneous electrical nerve stimulation on somatosensory evoked potentials.

Transcutaneous electrical nerve stimulation (TENS) is an electrotherapeutic modality used for analgesia. We planned to demonstrate selective stimulation of large diameter fibers with conventional type TENS by way of somatosensory evoked potentials (SEP). We have analyzed index finger-wrist segment median nerve sensory potential and SEP recordings obtained from C2 and Cc before TENS and at 5, 10 and 15 minutes of TENS application of 14 adult healthy volunteers. SEP and finger-wrist segment sensory nerve conduction amplitudes were significantly decreased compared to pre-TENS values during 5, 10, and 15 minutes of TENS application (p < 0.05). These results reflect the selective stimulation of large diameter afferent fibers of conventional type TENS.