Cold-Stored Venous Allografts In Different Preserving Solutions: A Study On Changes In Vein Wall Morphology

BACKGROUND:

The saphenous vein is the most frequently used bypass conduit for vascular reconstructions, which may need to be stored for a prolonged time. The aim of this study was to compare the effect of different preservation solutions on the morphology of saphenous veins during the long-term cold storage.

DESIGN:

An in vitro study.

MATERIAL AND METHODS:

Saphenous vein samples, collected from 29 patients undergoing varicose vein surgery, were stored at +4°C in (1) 10% formalin, (2) isotonic saline with heparin and antibiotic, (3) phosphate-buffered saline, (4) 2.5% glutaraldehyde + phosphate-buffered saline, and (5) Custodiol (histidine-tryptophan-ketoglutarate). Changes in the vein wall were histologically investigated up to day 35. Possible retention of the capacity of endothelial function was evaluated by immunohistochemical detection of endothelial nitric oxide synthase.

RESULTS:

Formalin as the control medium well preserved the vein wall morphology, but endothelial nitric oxide synthase immunostaining was very weak. Phosphate-buffered saline and isotonic saline with heparin and antibiotic poorly preserved vein wall morphology. Phosphate-buffered saline endothelial nitric oxide synthase staining decreased dramatically throughout the study period. Compared to phosphate-buffered saline, stronger isotonic saline with heparin and antibiotic endothelial nitric oxide synthase staining was noted at day 35 (p < 0.001). Custodiol and glutaraldehyde better preserved vein morphology compared to ISHA and PBS at day 5 and later (p < 0.001), but compared to stronger isotonic saline with heparin and antibiotic their endothelial nitric oxide synthase staining was weaker.

CONCLUSION:

In terms of preserving the morphology of saphenous veins, phosphate-buffered saline and isotonic saline with heparin and antibiotic were the poorest, while Custodiol and glutaraldehyde were the best. Demonstrating good retention of endothelial nitric oxide synthase staining throughout the study period, isotonic saline with heparin and antibiotic seems to have the best potential to retain vein wall functionality, despite relatively poor morphological preservation.

Rod-through-plate fixation of canine diaphyseal fractures

Efficacy of the rod-through-plate fixation for fracture repair was evaluated in six clinical cases of canine long bone fractures. This fixation incorporates principles of intramedullary and extramedullary osteosynthesis for transverse and short oblique fractures of long tubular bones. The plate-through-rod device is comprised of one pair of curved rods, a connecting plate and two bone screws. The connecting plate has both a hole and a channel on each end. Curved rods have a long curved part and a straight part with a hole in it for screw fixation. All components are made up of medical stainless steel. Clinical and radiographical examinations were performed from week seven to18 months after the operation. Functional abnormalities were not observed at this period in five patients and all fractures were healed. In one patient screw stripping in the proximal fragment of the femur was detected radiologically and minimal implant dislocation was noted at seven weeks after the initial repair. The rod-through-plate fixation method gives strong fixation of bone fragments with minimal traumatization of soft tissue during the operation. The design of the rod-through-plate is intended to reduce pressure of the plate on the cortex in the area of the fracture, whereas the dynamic fixation provided by the intramedullary rods may allow micromotion, thus stimulating callus formation and avoiding implant- induced osteoporosis. Clinical relevance: The rod-through-plate fixator has a simple construction and its use expands the treatment possibilities for diaphyseal fractures of long bones.

Age-related changes in apoptosis and expressions of intercellular adhesion molecule-1 and vascular endothelial growth factor receptor type 2 in the wall of varicose veins

AIM

Dysregulated apoptosis in the venous wall is believed to play important role in the onset and progression of human primary varicose veins. The aim of our study was to in situ investigate the apoptosis of endothelial cells (EC) and smooth muscle cells (SMC) together with the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular endothelial growth factor receptor type 2 (VEGF R2) in the varicose veins of women of different age groups.

METHODS

Women (n=34) undergoing surgery for varicosities were divided into three groups: Group I (younger than 35 year); Group II (36-50 years); Group III (older than 50 years). Apoptotic EC and SMC were determined by the TUNEL method. ICAM-1 and VEGF R2 were detected immunohistochemically in the endothelium, the subendothelial layer, the media and the adventitia.

RESULTS

The number of apoptotic EC and SMC rose in the group of older patients (Group III vs Group I; P<0.01 and P<0.05, respectively). In the same group ICAM-1 immunostaining was increased in the endothelium, but decreased in the media and the adventitia, while VEGF R2 staining was increased in the endothelium, the subendothelial layer and the media, but decreased in the adventitia.

CONCLUSION

In conclusion, our study demonstrated that apoptosis of EC and SMC increase in varicose veins with advancing age and age-related differences exist also in the expression of ICAM-1 and VEGF R2 in the wall of varicose veins of women.

Complete glutathione system in probiotic Lactobacillus fermentum ME-3

There is much information about glutathione (GSH) in eukaryotic cells, but relatively little is known about GSH in prokaryotes. Without GSH and glutathione redox cycle lactic acid bacteria (LAB) cannot protect themselves against reactive oxygen species. Previously we have shown the presence of GSH in Lactobacillus fermentum ME-3 (DSM14241). Results of this study show that probiotic L. fermentum ME-3 contains both glutathione peroxidase and glutathione reductase. We also present that L. fermentum ME-3 can transport GSH from environment and synthesize GSH. This means that it is characterized by a complete glutathione system: synthesis, uptake and redox turnover ability that makes L. fermentum ME-3 a perfect protector against oxidative stress. To our best knowledge studies on existence of the complete glutathione system in probiotic LAB strains are still absent and glutathione synthesis in them has not been demonstrated.

[Cytological study of the kidney ischemic lesions in rats]

The course of reparative regeneration after 5/6 nephrectomy and use of low-dose radiation has been studied by means of light and electron microscopy. The experiments were performed on 30 male Wistar rats. All animal procedures were conducted after approval of the protocol by the animal Studies Ethics Committee of the University of Tartu. Renal ablation was then accomplished by right nephrectomy and selective ligation of extrarenal branches of the left renal artery such that approximately 2/3 of the left kidney was infracted. All together 30 rats were randomised after the surgery and divided into two groups matched for age and body weight at week 0 and studied during 2, 4 and 8 weeks: groups I (nephrectomized, n = 15), groups II (nephrectomized and irradiated, n = 15). Left kidney of II groups rats was irradiated (60Co) 24 h after surgery in anaesthetized (Brietal) animals with 3 Gy in a single dose. As a result of experimentally induced ischemia destruction of renal corpuscles, perishing of tubular epithelial cells and and proliferation of connective tissue is followed. Reparative regeneration is based on aseptic inflammation, duration of its phases depends on the extent of organ impairment. In nephrectomized rats parallel to reparative regeneration, necrosis and deposition of calcium is found in the cortical substance. Calcium plays important role in kidney metabolism and its increased content is characteristic to degenerative changes. The experiments reveal that use of low-dose radiation does not accelerate process of reparative regeneration in rat kidney.

Rod-through-plate fixation of canine diaphyseal fractures

Efficacy of the rod-through-plate fixation for fracture repair was evaluated in six clinical cases of canine long bone fractures. This fixation incorporates principles of intramedullary and extramedullary osteosynthesis for transverse and short oblique fractures of long tubular bones. The plate-through-rod device is comprised of one pair of curved rods, a connecting plate and two bone screws. The connecting plate has both a hole and a channel on each end. Curved rods have a long curved part and a straight part with a hole in it for screw fixation. All components are made up of medical stainless steel. Clinical and radiographical examinations were performed from week seven to18 months after the operation. Functional abnormalities were not observed at this period in five patients and all fractures were healed. In one patient screw stripping in the proximal fragment of the femur was detected radiologically and minimal implant dislocation was noted at seven weeks after the initial repair. The rod-through-plate fixation method gives strong fixation of bone fragments with minimal traumatization of soft tissue during the operation. The design of the rod-through-plate is intended to reduce pressure of the plate on the cortex in the area of the fracture, whereas the dynamic fixation provided by the intramedullary rods may allow micromotion, thus stimulating callus formation and avoiding implant-induced osteoporosis.

CLINICAL RELEVANCE

The rod-through-plate fixator has a simple construction and its use expands the treatment possibilities for diaphyseal fractures of long bones.

Histopathological changes and expression of adhesion molecules and laminin in varicose veins

Background: Although varicose disease is a common pathology, etiologic factors predisposing to dilatation, elongation and tortuosity of the saphenous vein are not yet well understood. The aim of our study was to investigate morphological changes, laminin and adhesion molecules expression in the great saphenous vein. Patients and methods: Material obtained from 26 patients was analyzed using light microscopy, immunohistology and electron microscopy. Patients were divided into two age groups (group I, aged between 26 and 35 years and group II, 36–45 years). Results: In most patients veins were stretched out with highly varying wall thickness. The vein wall three-layered structure composed of intima, media and adventitia was changed in 78% of the cases. In most specimens endothelium was either damaged or missing. In such areas possible thrombus formation sites were observed characterized by erythrocyte accumulation. In media and adventitia smooth muscle cells were destroyed or showed altered morphology, the amount of connective tissue was increased together with irregular organization of collagen fibers and disruption of the elastic network around smooth muscle cell bundles. Laminin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression was increased in varicose veins wall, especially in the second group of patients (p<0.05). In addition, ICAM-1 and VCAM-1 expression was more pronounced in the wall of varicose veins of female than male patients (p < 0.05). Conclusion: We conclude that morphological alterations in varicose veins become more pronounced with advancing age, and laminin, ICAM-1 and VCAM-1 expression is related to the severity of damage and age of the patient.

Prostaglandins of the E-series inhibit connective tissue proliferation in the liver wound of the rat

The present study was undertaken to relate wound healing of an internal organ to prostaglandins of the E and F series. A small liver wound was induced by a galvanic cauter via the abdominal route under general anesthesia and prostaglandin E1, E2 and F2alpha were injected twice daily at a dose of 250 microg/kg. Proliferation of the connective tissue in the liver wound was estimated morphometrically 6 days after liver wound infliction. Levels of prostaglandins E2 and F2alpha were measured in the liver wound as well as in normal liver tissue from adjacent lobes using radioimmunoassay. The results show that exogenous prostaglandins of the E-series suppress connective tissue proliferation. Three minutes after the last prostaglandin E2 injection, high prostaglandin concentrations were measured both in the liver wound and in the liver tissue of the adjacent lobe. Prostaglandin F2alpha injections had no effect on wound healing. We believe that the rat thermic liver wound model can be used for different studies on wound healing mechanisms and that prostaglandins of the E-series are involved in wound healing in the specific time period studied.

[Morphological and ultrastructural changes in the rat kidney after experimental sepsis]

Experimental sepsis was investigated in 42 male white Wistar rats. The animals were divided into 7 equal groups. Suspended E. coli cells (2 x 10(7) per 100 g body weight) were injected into the tail vein in groups I-VI, group VII served as a control group. The rats were sacrificed with cervical dislocation at different times after injection: in 45 min (group I), 2 h (group II), 6 h (group III), 24 h (group IV), 48 h (group V), and 120 h (group VI). Samples of kidneys were taken and embedded in paraffin and EPON-812 for histological and electron microscopical evaluation, respectively.

RESULTS

histological examination demonstrated that changes in kindeys started in 2 h after infection to achieve the maximum level in 24 h, showing thereafter a tendency to decrease. A significant tissue damage was first seen in the loop and distal tubules of nephrons, and then expanded to the proximal tubules. Electron microscope examination demonstrated that changes in podocytes and cytopodia could be distinctly differentiated in 2 h after infection and obviously increased in the course of the experiment. The podocytes were enlarged, the processes were expanded and adhered to each other. For that reason the number of filtration pores in the glomerular basal membrane decreased. The count of mesangial cells in the glomerulus was increased.

["Light" epithelial cells of swine and bovine oviducts]

The ultrastructure of oviduct epithelium of clinically healthy cows and 15 sows was investigated using scanning and transmission electron microscopy. In all parts of the oviduct, ciliated and non-ciliated epithelial cells are present, but their number varies in both the investigated animals in different regions of the oviduct, depending on the phase of the estrous cycle. In addition to ciliated cells with numerous cilia on their luminal surface, so-called pale ciliary cells were found in all parts of the oviduct of cows and sows. The cytoplasm of these cells is electron-lucent, their luminal surface carries few cilia and short microvilli. The apical cytoplasm contains species specific secretory granules, which means that these cells have features characteristic of both secretory and ciliated cells. It is suggested that the pale ciliated and non-ciliated secretory cells are functional stages of the same tubar epithelium cell, and that the transformation between these two cell types is regulated by functional requirements of the organ in different phases of the estrous cycle.

[Morphological changes in the kidney after 5/6 nephrectomy and low-dose radiation]

In the present study, we investigated the effect of low-dose irradiation of experimental nephrectomized rats. We hypothized that the low-dose irradiation may slow down the development of focal-segmented glomerulosclerosis (FSGS) after 5/6 nephrectomy. Experiments were performed with 32 male Wistar rats, divided into four groups. The first group contained only operated animals. Animals in the second and third groups were irradiated on the next day after operation with 1 and 3 Gy, respectively. The healthy animals made the forth, control group. Attention was focused on physiological and morphological changes after low-dose (1 and 3 Gy) irradiation. We measured blood pressure, proteinuria, serum creatinin and cysC. Morphological changes of glomerulus and tubules were studied. Animals of the first group had significantly thicker glomerular basement membrane, compared to animals of other groups. The morphological study demonstrated degeneration of the tubular epithelium, tubular atrophy and FSGS. Besides, it was shown that changes in the third group (3 Gy) were less than in nephrectomized (first group) and 1 Gy (second group). The animals of the third group (3 Gy) had significantly lower proteinuria and FSGS. We conclude that our hypothesis, suggesting that low-dose irradiation slows down the development of FSGS, was confirmed.

Proliferation potential of human lumbar disc after herniation

To investigate the regenerative potential of human disc tissue, the disc samples were obtained during surgery from 24 adult patients with first lumbar prolapses and from 14 patients with recurrent lumbar prolapses. Preoperative magnetic resonance imaging (MRI) confirmed prolapse and disc degeneration in all cases. The proliferation activity of the sampled connective tissue cells was studied with the immunohistochemical expression of Ki-67(MIB-1) antigen. The antigen was positive in 6 of 24 (25%) specimens from first prolapse and in none of the 14 specimens from the recurrent prolapse. The amount of proliferative cells did not correlate to the degree of disc degeneration in MRI. Our results indicate that connective tissue cells in adult degenerative disc may show proliferation activity after the first herniation and thus regenerative potential. The enhanced matrix proliferation may not be a significant reason for recurrent prolapses because none of the recurrent disc specimen showed proliferation activity.