Expression of KIF3C kinesin during neural development and in vitro neuronal differentiation.

KIF3A, KIF3B and KIF3C are kinesin-related motor subunits of the KIF3 family that associate to form the kinesin-II motor complex in which KIF3C and KIF3B are alternative partners of KIF3A. We have analysed the expression of Kif3 mRNAs during prenatal murine development. Kif3c transcripts are detectable from embryonic day 12.5 and persist throughout development both in the CNS and in some peripheral ganglia. Comparison of the expression patterns of the Kif3 genes revealed that Kif3c and Kif3a mRNAs colocalize in the CNS, while only Kif3a is also present outside the CNS. In contrast, Kif3b is detectable in several non-neural tissues. We have also performed immunocytochemical analyses of the developing rat brain and have found the presence of the KIF3C protein in selected brain regions and in several fibre systems. Using neuroblastoma cells as an in vitro model for neuronal differentiation, we found that retinoic acid stimulated the expression of the three Kif3 and the kinesin-associated protein genes, although with different time courses. The selective expression of Kif3c in the nervous system during embryonic development and its up-regulation during neuroblastoma differentiation suggest a role for this motor during maturation of neuronal cells.

Metabolism and trafficking of N-type voltage-operated calcium channels in neurosecretory cells.

The N-type voltage-operated calcium channel has been characterized over the years as a high-threshold channel, with variable inactivation kinetics, and a unique ability to bind with high affinity and specificity omega-conotoxin GVIA and related toxins. This channel is particularly expressed in some neurons and endocrine cells, where it participates in several calcium-dependent processes, including secretion. Omega-conotoxin GVIA was instrumental not only for the biophysical and pharmacological characterization of N-type channels but also for the development of in vitro assays for studying N-type VOCC subcellular localization, biosynthesis, turnover, as well as short-and long-term regulation of its expression. We here summarize our studies on N-type VOCC expression in neurosecretory cells, with a major emphasis on recent data demonstrating the presence of N-type channels in intracellular secretory organelles and their recruitment to the cell surface during regulated exocytosis.

[The use of allografts in the surgical treatment of patients with infected vascular prostheses]. / Ispol'zovanie allotransplantatov v khirurgicheskom lechenii bol'nykh s infitsirovannymi sosudistymi protezami.

The article is devoted to analysis of surgical treatment of patients with such a dangerous complication as infection of the vascular prosthesis. The authors have performed 25 operations for substituting the infected prostheses for allografts. In 18 patients the infected prostheses were located in the aorto-iliac segment, in 5 patients in the femoro-popliteal segment, 1 patient had it in the aorta, and 1 in the subclavian segment. The prostheses were removed and a simultaneous revascularization was made. The authors make a conclusion that it is very expedient to use alloprostheses as a protective measure against persistent or recidivating infections. The allografts have both early and long-term resistance to infection.

The use of arterial allografts in aortic graft infections. A three year experience on eighteen patients.

BACKGROUND: We describe our experience in the treatment of aortic graft infections by replacing them with arterial homografts as suggested by the good results recently described. METHODS: Between March 1994 and March 1997 eighteen patients with infections of the aortofemoral bifurcation segments have been treated. All patients underwent a complete explantation of the infected graft and an in situ revascularization with arterial homograft harvested in multiorgan removal. Eight segments were freshly preserved, 10 were cryopreserved. Four patients were operated as emergencies, of which 3 for aorto-enteric fistulas. All others presented a serious septic state. RESULTS: Three patients died in the early postoperative period: one of acute infarction and two of homograft related causes. In the follow-up there was only one death from acute infarction, a branch occlusion and two allograft enteric fistulas successfully treated by surgery. All surviving patients are submitted to periodical haemodynamic and tomographic control with an average follow-up of 22 months (range 3 months to 3 years) and there has been no allograft degeneration so far. CONCLUSIONS: The use of homologue arterial allografts has shown good results in the treatment of serious aortic graft infections resulting in adequate peripheral vascularization. There have been no significant degenerations to date, either in fresh or cryopreserved allografts.

[Our experience in the emergency treatment of secondary aortoenteric fistulae. The preliminary results of the use of aortic homografts]. / La nostra esperienza nel trattamento in urgenza delle fistole aorto-enteriche secondarie. Preliminari sull'uso di homograft aortici.

The digestive prosthetic aortic fistulas are connections between an aortic prosthesis and the duodenum. From January 1988 to January 1994, in the vascular surgery section of Busto Arsizio hospital, 12 patients received emergency treatment for digestive aortic fistulas, with a prosthesis being positioned extra-anatomically. A different treatment was used for three patients who were treated during the period from January 1994 to July 1994. For the second group the old prosthesis was replaced by a homograft. On the first group of 12 patients, 5 had previously been operated on for obstructive arteriopathy of the legs; the other 7 had previously been operated on for an abdominal aortic aneurysm. In 50% of these 12 cases the prosthesis used was a bifemoral aortic prosthesis, in 30% bisiliac aortic, and in 20% an aorto aortic prosthesis. There was an interval, from one month to 20 years depending on the patient, between the first and the second operations. The average age of the patients was 61.2 years. Six of the patients were extreme emergency cases and were operated on immediately on their arrival at the hospital, while the other 6 were operated on 2-3 days after their arrival. Five patients died whilst they were being operated on (3 from haemorrhagic shock, 2 from sepsis and multi-organ failure). None of the patients who were treated from January 1994 to July 1994 died during their operations. The homograft was removed from a multi-organ donor. In treatment such as this, the most important thing is to remove the old prosthesis. The following is a discussion of the techniques used to clamp the aorta and to provide alternative limb vascularization.