Heterodimeric neurotrophins induce phosphorylation of Trk receptors and promote neuronal differentiation in PC12 cells

Neurotrophins are a family of highly conserved proteins that affect the development and maintenance of distinct neuronal populations. Neurotrophins exist in vivo as homodimers, but we show that neurotrophins can exist as heterodimers in vitro and are pluripotent, being able to bind and to activate different Trk tyrosine kinase receptors as well as promote neuronal differentiation in PC12 cells as effectively as wild type homodimers. These asymmetric neurotrophin dimers allow unique characterization of neurotrophin structure-function relationships with Trk receptors. The chimeric Trk activities of these heterodimers suggest an alternative model of neurotrophin-Trk receptor activation in which the critical Trk-interacting elements may be attributed to a single protomer.     

A model of the electrocortical effects of general anaesthesia

INTRODUCTION: Iodine containing agents are used as radiologic contrast media and for the treatment of upper respiratory infections, heart diseases, thyreotoxicosis, erythema nodosum and wound disinfection. Vegetating iododerma is a rare but severe cutaneous side effect. CASE STUDY: We report a case of iododerma in a 84 year-old patient, presenting iododerma 14 months after introduction of amiodarone treatment. Despite cessation of this therapy, an important exacerbation of the skin lesions was observed 3 months later. Therapy with cyclosporine produced a marked regression of the skin lesions. DISCUSSION: We are aware of only one other reported case of amiodarone induced iododerma, which occurred after 2 years of therapy. Our patient was also exposed to iodine containing radiographic contrast media 1 and 18 years before onset of the actual skin disease. A sensitizing role of these injections is possible, but we feel that they did not directly induce the skin eruption as all reported cases occurred within a few days after exposure. CONCLUSION: Amiodarone can exceptionally be responsible for severe iododerma. Cyclosporine is, according to our experience, a valuable therapeutic option.     

Making the best use of consultant orthodontic services, Part 2: How to undertake the referral

There is little information on the microbiology of periapical lesions, and no data on the residual microbial flora in the periapex, if any, after apicoectomy procedures. Hence, 64 patients treated by apicoectomy procedures were prospectively studied to assess the bacterial flora in the periapex and to evaluate the residual bacteria in postoperative apicoectomy sites. Of the 64 lesions studied, 14 (22%) were sterile and 50 (78%) yielded bacteria preoperatively. Bacteria could be recovered from 28 (56%) of the latter lesions after apicoectomy and curettage. A total of 105 bacterial strains was isolated from 50 lesions, yielding a range of 1-4 (mean 2.1) species per sample. The isolates comprised 84 (80%) facultative anaerobes and 21 (20%) strict anaerobes. A polymicrobial growth was obtained from 39 lesions whilst 11 lesions yielded pure cultures. On detailed microbiological analyses of 29 lesions, 40% of the isolates were identified as alpha-haemolytic streptococci, half of which were Streptococcus sanguis; anaerobic streptococci were the predominant anaerobes. None of the organisms or group(s) of organisms emerged as recalcitrant colonisers which were difficult to dislodge after surgical debridement. These data indicate that the majority of periapical lesions harbour a variety of flora which cannot be eradicated despite thorough apicoectomy procedures.     

Effects of aerobic exercise training and yoga on the baroreflex in healthy elderly persons

It is unclear whether the age-associated reduction in baroreflex sensitivity is modifiable by exercise training. The effects of aerobic exercise training and yoga, a non-aerobic control intervention, on the baroreflex of elderly persons was determined. Baroreflex sensitivity was quantified by the alpha-index, at high frequency (HF; 0.15-0.35 Hz, reflecting parasympathetic activity) and mid-frequency (MF; 0.05-0.15 Hz, reflecting sympathetic activity as well), derived from spectral and cross-spectral analysis of spontaneous fluctuations in heart rate and blood pressure. Twenty-six (10 women) sedentary, healthy, normotensive elderly (mean 68 years, range 62-81 years) subjects were studied. Fourteen (4 women) of the sedentary elderly subjects completed 6 weeks of aerobic training, while the other 12 (6 women) subjects completed 6 weeks of yoga. Heart rate decreased following yoga (69 +/- 8 vs. 61 +/- 7 min-1, P < 0.05) but not aerobic training (66 +/- 8 vs. 63 +/- 9 min-1, P = 0.29). VO2 max increased by 11% following yoga (P < 0.01) and by 24% following aerobic training (P < 0.01). No significant change in alpha MF (6.5 +/- 3.5 vs. 6.2 +/- 3.0 ms mmHg-1, P = 0.69) or alpha HF (8.5 +/- 4.7 vs. 8.9 +/- 3.5 ms mmHg-1, P = 0.65) occurred after aerobic training. Following yoga, alpha HF (8.0 +/- 3.6 vs. 11.5 +/- 5.2 ms mmHg-1, P < 0.01) but not alpha MF (6.5 +/- 3.0 vs. 7.6 +/- 2.8 ms mmHg-1, P = 0.29) increased. Short-duration aerobic training does not modify the alpha-index at alpha MF or alpha HF in healthy normotensive elderly subjects. alpha HF but not alpha MF increased following yoga, suggesting that these parameters are measuring distinct aspects of the baroreflex that are separately modifiable.     

Bone grafting the piriform aperture deformity in isolated cleft lip patients: indication, technique, and results

PURPOSE: This study was undertaken to determine the effect of a bone graft in the piriform aperture on the nasal deformity and orthodontic treatment of the cleft side teeth in isolated cleft lip patients. PATIENTS AND METHODS: All primary cleft lip repair was done 3 months after birth. Nine patients, four female and five male, with a mean age of 12.5 years (range, 8.2 to 24.8 years) and with a repaired cleft lip, were bone grafted between 1992 and 1996. The mean postoperative period was 2 years (range, 1 to 4 years). An iliac crest bone graft was placed in the piriform aperture deformity on the side of the cleft lip. The improvement in the nasal symmetry and angulation of the cleft side teeth were evaluated. The eight growing cleft lip patients (mean age, 11 years; range, 9 to 13 years) were compared with a control group of eight healthy growing children (mean age, 11 years; range, 9 to 13 years). The improvement of nasal symmetry was measured by the formula of the lobule portion of the columella index preoperatively and postoperatively. RESULTS: The mean lobule portion of the columella index preoperatively was 41.8% (SD, 4.4%; SE of Mean, 1.5%) and postoperatively was 44.2% (SD, 4.9%; SE of Mean, 1.6%) (P > .006, t-test for paired samples). The angulation of the cleft side teeth was improved by orthodontic treatment. CONCLUSION: Bone grafting the piriform aperture deformity results in a stable result and improves nasal symmetry and the angulation of the cleft side teeth.     

A comparison of natural and recombinant cholera toxin B subunit as stimulatory factors in intranasal immunization

Cholera toxin B (CTB) is often envisaged and used as an immune stimulating agent in protocols for mucosal immunization. However, the nature of the CTB used (natural vs recombinant) is frequently not taken in consideration. This is important since the usage of natural CTB in mucosal immunization regimen and the mucosal response resulting from such an immunization can be effected by the presence of the CTA subunit in commercial CTB preparations. To clarify this, we have compared natural vs recombinant CTB in an intranasal (i.n.) mucosal immunization procedure using ovalbumin (OVA) as antigen. The results show that recombinant CTB induces similar immune responses like natural CTB. Furthermore, our experiments show that covalent coupling of OVA to CTB is not required for the induction of OVA specific mucosal and systemic immune responses upon i.n. immunization.     

Intraoral morbidity following free buccal mucosal graft harvesting for urethroplasty

Buccal mucosa is the preferred donor tissue for urethroplasty in many cases. This study documents donor site morbidity associated with this technique in 12 patients. Nine patients had a transiently decreased parotid salivary flow for 1 week, and one patient reported transient nerve involvement (long buccal nerve). Intraincisal opening returned to presurgical values within 6 weeks and in some cases exceeded presurgical values. This appears to be a low morbidity technique with high patient acceptance.     

Reconstruction of the superior vena cava: benefits of postoperative surveillance and secondary endovascular interventions

PURPOSE: Superior vena cava (SVC) reconstructions are rarely performed; therefore the need for surveillance and the results of secondary interventions are unknown. METHODS: During a 14-year period 19 patients (11 male, 8 female; mean age 41.9 years, range 8 to 69 years) underwent SVC reconstruction for symptomatic nonmalignant disease. Causes included mediastinal fibrosis (n = 12), indwelling foreign bodies (n = 4), idiopathic thrombosis (n = 2), and antithrombin III deficiency (n = 1). Spiral saphenous vein graft (n = 14), polytetrafluoroethylene (n = 4), or human allograft (n = 1) was implanted. RESULTS: No early death or pulmonary embolism occurred. Four early graft stenoses or thromboses (spiral saphenous vein graft, n = 2, polytetrafluoroethylene, n = 2) required thrombectomy, with success in three. During a mean follow-up of 49.5 months (range, 4.7 to 137 months), 95 imaging studies were performed (average, five per patient; range, one to 10 studies). Venography detected mild or moderate graft stenosis in seven patients; two progressed to severe stenosis. Two additional grafts developed early into severe stenosis. Four of 19 grafts occluded during follow-up (two polytetrafluoroethylene, two spiral saphenous vein graft). Computed tomography failed to identify stenosis in two grafts, magnetic resonance imaging failed to confirm one stenosis and one graft occlusion, and duplex scanning was inconclusive on graft patency in 10 patients. Angioplasty was performed in all four patients with severe stenosis, with simultaneous placement of Wallstents in two. One of the Wallstents occluded at 9 months. Repeat percutaneous transluminal angioplasty was necessary in two patients, with placement of Palmaz stents in one. Only one graft occlusion and one severe graft stenosis occurred beyond 1 year. The primary, primary-assisted, and secondary patency rates were 61%, 78%, and 83% at 1 year and 53%, 70%, and 74% at 5 years, respectively. CONCLUSION: Long-term secondary patency rates justify SVC grafting for benign disease. Postoperative surveillance with contrast venography is indicated in the first year to detect graft problems. Endovascular techniques may salvage and improve the patency of SVC grafts.