Reconstruction of orbital floor fracture using solvent-preserved bone graft

The orbital floor is one of the most frequently damaged parts of the maxillofacial skeleton during facial trauma. Unfavorable aesthetic and functional outcomes are frequent when it is treated inadequately. The treatment consists of spanning the floor defect with a material that can provide structural support and restore the orbital volume. This material should also be biocompatible with the surrounding tissues and easily reshaped to fit the orbital floor. Although various autografts or synthetic materials have been used, there is still no consensus on the ideal reconstruction method of orbital floor defects. This study evaluated the applicability of solvent-preserved cadaveric cranial bone graft and its preliminary results in the reconstruction of the orbital floor fractures. Twenty-five orbital floor fractures of 21 patients who underwent surgical repair with cadaveric bone graft during a 2-year period were included in this study. Pure blowout fractures were determined in nine patients, whereas 12 patients had other accompanying maxillofacial fractures. Of the 21 patients, 14 had clinically evident diplopia (66.7 percent), 12 of them had enophthalmos (57.1 percent), and two of them had gaze restriction preoperatively. Reconstruction of the floor of the orbit was performed following either the subciliary or the transconjunctival approach. A cranial allograft was placed over the defect after sufficient exposure. The mean follow-up period was 9 months. Postoperative diplopia, enophthalmos, eye motility, cosmetic appearance, and complications were documented. None of the patients had any evidence of diplopia, limited eye movement, inflammatory reactions in soft tissues, infection, or graft extrusion in the postoperative period. Providing sufficient orbital volume, no graft resorption was detected in computed tomography scan controls. None of the implants required removal for any reason. Enophthalmos was seen in one patient, and temporary scleral show lasting up to 3 to 6 weeks was detected in another three patients. Satisfactory cosmetic results were obtained in all patients. This study showed that solvent-preserved bone, which is a nonsynthetic, human-originated, processed bioimplant, can be safely used in orbital floor repair and can be considered as another reliable treatment alternative.     

Effects of irrigation and air humidity preconditioning on water relations, growth and survival of Rosmarinus officinalis plants during and after transplanting

The effect of different irrigation and air humidity conditioning treatments on the morphological and physiological responses of Rosmarinus officinalis in nursery conditions was investigated in order to evaluate the degree of hardening resulting from these conditions. Rosmarinus officinalis seedlings were pot-grown during 4 months in two greenhouses (nursery period), in which two irrigation treatments were used (control and deficit). In one of these greenhouses, air humidity was controlled using a dehumidifying system (low humidity), in the other greenhouse the air conditions were not artificially modified (control humidity). After the nursery period, the plants of all treatments were transplanted and well watered (100% water holding capacity for 1 month, transplanting period). After this period, they received no water (establishment period). At the end of the nursery period it was seen that deficit irrigation had altered the morphology of the R. officinalis plants by reducing plant height, stem diameter, leaf area, total dry weight, and root length, while humidity influenced the parameters related with plant water relations. Low air humidity and deficit irrigation-induced tissue dehydration and lower stomatal conductance values (gs). The plants subjected to deficit irrigation developed leaf osmotic adjustment, which was maintained during the transplanting period. At that time, the plants that had been exposed to deficit irrigation and low humidity showed efficient stomatal regulation (lower gs values). After transplanting and during the establishment period, these plants showed a better water status (higher psil and gs values). Their post-planting survival rate improved as a result of acclimation processes.     

An accumulation of insulin-like growth factor I (IGF-I) in human myometrium and uterine leiomyomas in various stages of tumour growth

It is commonly thought that uterine leiomyomas result from hyperstimulation of myometrium by ovarian hormones. Some observations suggest that cytokines and growth factors are intermediate elements through which the ovarian hormones may exert their growth-stimulatory effects on leiomyomas. Human myometrium and uterine leiomyomas of various weights were homogenised and extracted with 1 M acetic acid or with 0.05 M Tris/HCl, pH 7.6. The extracts were assayed for IGF-I using the ELISA technique. It was found that 0.05 M Tris/HCl extracts contained several times more IGF-I than the 1 M acetic acid extracts. Nanogram amounts of IGF-I were found in both control myometrium and in leiomyomas. It was found that the amounts of IGF-I extracted from leiomyomas were distinctly higher in comparison to control myometrium and they increased as a function of tumour growth. Polyacrylamide gel electrophoresis, followed by Western immunoblotting, demonstrated that IGF-I in acidic and alkaline extracts exists as stable complexes, probably with extracellular matrix components. No free IGF-I was detected. Furthermore, it was found that some components of both the acidic and alkaline extracts were able to bind exogenous (125)I-labeled IGF-I. It is suggested that IGF-I plays an important role both in myometrium biology and in the growth of uterine leiomyomas.     

Gramicidin A channel as a test ground for molecular dynamics force fields

We use the well-known structural and functional properties of the gramicidin A channel to test the appropriateness of force fields commonly used in molecular dynamics (MD) simulations of ion channels. For this purpose, the high-resolution structure of the gramicidin A dimer is embedded in a dimyristoylphosphatidylcholine bilayer, and the potential of mean force of a K(+) ion is calculated along the channel axis using the umbrella sampling method. Calculations are performed using two of the most common force fields in MD simulations: CHARMM and GROMACS. Both force fields lead to large central barriers for K(+) ion permeation, that are substantially higher than those deduced from the physiological data by inverse methods. In long MD simulations lasting over 60 ns, several ions are observed to enter the binding site but none of them crossed the channel despite the presence of a large driving field. The present results, taken together with many earlier studies, highlights the shortcomings of the standard force fields used in MD simulations of ion channels and calls for construction of more appropriate force fields for this purpose.     

The role of stress proteins HSP70 and the adrenergic system in different resistance to myocardial infarction of August and Wistar genetic rat strains]

A lesser resistance against myocardial infarction (MI) in the Wistar rats as compared with the August rats was found to be combined with a greater stress-response and activation of the heart sympathetic regulation in the former rats. In the Wistar rats and not in August rats, an activation of hypothalamic noradrenaline (NA) system occurs as well as a greater "output" of the NA from sympathetic terminals in the myocardium. Accumulation of the HSP 70 stress-proteins in IM in the myocardium is nearly 2-2.5-fold lesser in the Wistar rats. Thereupon, different resistance against the IM in Wistar and August rats seems to be due to a genetically determine differences in intensity of the stress-response, activation of the heart sympathetic regulation in the IM, and production of the HSP 70 protective stress-proteins in the myocardium.     

Adrenomedullin binding protein-1 modulates vascular responsiveness to adrenomedullin in late sepsis

Adrenomedullin (AM), a potent vasodilatory peptide, plays an important role in initiating the hyperdynamic response during the early stage of sepsis. Moreover, the reduced vascular responsiveness to AM appears to be responsible for the transition from the early, hyperdynamic to the late, hypodynamic phase of sepsis. Although the novel specific AM binding protein-1 (AMBP-1) enhances AM-mediated action in a cultured cell line, it remains to be determined whether AMBP-1 plays any role in modulating vascular responsiveness to AM during sepsis. To study this, adult male rats were subjected to sepsis by cecal ligation and puncture (CLP). The thoracic aorta was harvested for determination of AM-induced vascular relaxation. Aortic levels of AMBP-1 were determined by Western blot analysis, and AM receptor gene expression in the aortic tissue was assessed by RT-PCR. The results indicate that AMBP-1 significantly enhanced AM-induced vascular relaxation in aortic rings from sham-operated animals. Although vascular responsiveness to AM decreased at 20 h after CLP (i.e., the late, hypodynamic stage of sepsis), addition of AMBP-1 in vitro restored the vascular relaxation induced by AM. Moreover, the aortic level of AMBP-1 decreased significantly at 20 h after CLP. In contrast, AM receptor gene expression was not altered under such conditions. These results, taken together, suggest that AMBP-1 plays an important role in modulating vascular responsiveness to AM, and the reduced AMBP-1 appears to be responsible for the vascular AM hyporesponsiveness observed during the hypodynamic phase of sepsis.     

Binding of the basic fibroblast growth factor (bFGF) by soluble components of human umbilical cord

Pre-eclampsia, the most common pregnancy associated syndrome, is connected with remodelling of extracellular matrix of the umbilical cord tissues. Since the fibroblast growth factor (FGF) is known to be a stimulator of collagen and glycosaminoglycan biosynthesis, one may expect that it plays an important role in such a remodelling. Studies performed on the umbilical cords of 10 control and 10 pre-eclamptic newborns demonstrated that both the umbilical cord arterial wall and Wharton's jelly contain FGF mainly in complexes with the components of different molecular mass. Pre-eclampsia is associated with a decrease of endogenous FGF-binding by soluble high molecular mass components of the umbilical cord. It is suggested that FGF released from these complexes may be actively bound by fibroblasts of the umbilical cord, stimulating them to produce collagen and sulphated glycosaminoglycans.