In ratio control, the control objective is to keep the ratio between two signals, normally flow measurements, at a desired value in spite of variations in setpoints and load disturbances, and possible control signal saturations. This paper presents a new ratio control scheme, the Tracking Ratio Station, that manages to handle all these situations. It is also able to keep the ratio when one of the

Pituitary adenylate cyclase activating peptide (PACAP) is expressed in a population of capsaicin-sensitive primary sensory neurons of small to medium size in the rat. In the present report we have examined the effect of sciatic nerve injury (unilateral transection) on PACAP expression (immunocytochemistry, radioimmunoassay, in situ hybridization and northern blot analysis) in dorsal root ganglia a

More than in any other European country, the modern history of Belarus is a product of World War II. The unification, homogenization and Sovietization of that country are all direct results of the war. World War II - or the Great Patriotic War, as the conflict is still called in Belarus - built legitimacy and constituted the raison d'etre for the political elite in the most conservative of the Sov

Time-dependent distribution of extracellular proteins (albumin, fibrinogen, fibronectin, collagen-I and IgG) in the interface zone between implant and soft tissue has been investigated utilizing a recently developed method. Commercially pure (c.p.) titanium and polytetrafluoroethylene (PTFE) implants were inserted in the abdominal wall of rats for 1, 6 and 12 weeks followed by a mild fixation, cry

Of the more than 2,000 Scandinavian newspapers published in North America prior to World War I, few have been preserved for posterity. One long-forgotten paper recently resurfaced: the Norwegian language newspaper Vikingen of Edmonton, Alberta, published by the Scandinavian Literary and Youth Societies on the eve of World War I. A survey of Vikingen’s editorials provides an insight into an active

Forty-four rat sciatic nerves with partial defects were repaired with a silicone chamber. Each partial defect was created by resecting a 10 mm segment from the tibial fascicle leaving the peroneal fascicle intact. The proximal and the distal stumps of the tibial fascicle together with the intact peroneal fascicle were encased in a single silicone chamber. After seven days a fibrin matrix had surro

The optimal time for nerve suture in transected rat sciatic nerve was investigated. The sciatic nerve on both side nerves were transected and repaired by an epineurial suture technique 0-28 days after nerve transection. The regeneration distance was measured by the sensory pinch reflex test 2-6 days after nerve repair. The initial delay period and the regeneration rate were calculated by using a n

In the present study, the authors reevaluated the temporal course and properties of neurotrophic activities present in the fluid accumulating in the silicone-chamber model for nerve regeneration. The fluid collected from silicone chambers was tested in four different dissociated neuronal cell cultures. Furthermore, the activity of the chamber fluid was examined, using a cell blot technique. There

We have developed a silicone nerve regeneration chamber that is partitioned into two compartments by a strip of nitrocellulose paper. The modified two-compartment chamber allows the investigation of the effects on rat sciatic nerve regeneration of trophic or growth factors that are initially bound to the nitrocellulose partition. In this study we compared the effects of untreated nitrocellulose, a

An extracellular matrix preparation, the human amnion membrane matrix (hAMM) can serve as a neurite-promoting substratum for cultured peripheral and central neurons, and also as a support for axonal growth in experimentally injured adult brain in vivo. In the present study, we tested similar materials as bridges in a silicone chamber model for the regeneration of sciatic nerve in the adult rat. Si

In the nerve regeneration silicone chamber model, the regenerate which forms across a 10-mm gap between proximal and distal nerve stumps is a monofascicular structure with an outer perineurial-like cell sheath. Recent work has provided indications that the geometry of the regenerate within a silicone chamber can be altered by experimental modifications of the chamber matrix. In the present study w

Gore-tex chambers were used to bridge a 6 mm gap between the proximal and distal nerve stumps of a rat sciatic nerve. The wall structure of these chambers is characterized by "nodes" interconnected by smaller fibrils. Chambers with internodal distances of 5, 10 and 30 microns were used. Some 30 microns chambers were coated from the outside with Gore-tex (0.2 micron internodal distance) and others

When silicone regeneration chambers are implanted empty, axonal regeneration fails if the interstump gap length is greater than 10 mm. Previous experiments using the 10-mm gap model demonstrated that regeneration success correlated with the dimension and/or consistency of the naturally formed acellular fibrin matrix. Both spatial and temporal parameters of regeneration could be stimulated through

We have compared the anatomic and functional regeneration of a transected sciatic nerve following regrowth from its proximal stump through either preformed empty mesothelial chambers or autologous nerve grafts bridging a 10 mm gap. Within the mesothelial chambers an organized multifascicular nerve trunk forms between the proximal and distal stumps. After 3 months, distal segment cross sections fro

In the present study, neuronal and Schwann cell marker proteins were used to biochemically characterize the spatiotemporal progress of degeneration/regeneration in the silicone chamber model for nerve regeneration. Rat sciatic nerves were transected and the proximal and distal stumps were inserted into a bridging silicone chamber with a 10-mm interstump gap. Using dot immunobinding assays, S-100 p

Experiments were performed on chloralose anaesthetized cats. A 2-cm segment of the proximal duodenum was isolated between two luminally situated balloons and perfused with isotonic saline containing [14C]-PEG 4000 as a non-absorbable marker. The perfusate was analysed with regard to alkalinity (back titration) and concentration of marker (liquid scintillation). Net alkalinization and net fluid tra

In the present study the inflammatory response was quantitatively evaluated during peripheral nerve regeneration. The fluid from silicone nerve regeneration chambers, inserted in rats, was collected during the early period of regeneration of transected sciatic nerves (6 h-7 d) and analysed with respect to inflammatory cells and mediators (leukotriene B4, LTB4, and interleukin-1 alpha, IL-1 alpha).

The possibility that collateral sprouting could occur from intact axons in an undamaged sciatic nerve was studied in the rat by suturing either a 7-day predegenerated or a fresh nerve segment in an end-to-side fashion to the sciatic nerve proper. Following a 14- or 35-day recovery period, the pinch reflex test was performed on the transplanted segment to demonstrate the presence of sensory axons.

Target-derived neurotrophic factors are of basic importance for survival of neurons. In the normal state, such neurotrophic factors, synthesized by the target tissues, are taken up by nerve terminals and transported by retrograde axonal transport in axons to the nerve-cell bodies to maintain their viability. After nerve injury, neurotrophic factors are synthesized by non-neuronal cells (Schwann ce