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C J Green

Publications and source records attributed to C J Green.

At least 127 records · Page 7Linked to original sources
PubMed1995

Scanning electron microscopic changes in morphology of pulmonary endothelium in rat lung isografts following hypothermic ischaemic storage and transplantation.

Endothelial monolayer integrity is a critical factor limiting vascular permeability of solid organs in transplantation. Several in vitro, ex vivo and in vivo studies suggest that damage to endothelial cells (EC) due to hypothermia and ischaemia-reperfusion injury causes morphological and functional damage to the endothelium leading to parenchymal oedema and haemorrhage. Aiming to study morphological changes to arterial pulmonary EC subjected to transplantation procedures, random scanning electron micrographs of vascular endothelium of rat lungs were taken. Forty-eight rat lungs were hypothermically stored for 48 or 72 hours in two different preservation solutions and studied either at the end of the cold storage period, or 5 min, 24 h or 4 weeks following transplantation. After 5 minutes of revascularization, micrographs showed EC shape variations, bleb formation and cell retraction with intercellular gap formation. Twenty-four hours after transplantation loss of monolayer continuity was widely extended. Four weeks of revascularization resulted in either well preserved specimens with nearly normal endothelium, or badly preserved arteries with fibrotic degeneration of the luminal vessel wall. The morphological disruptions found in this study help to explain the alterations in permeability control and vascular dysfunction observed in lung transplantation.

Animals↗
PubMed1995

Morphological changes in rat single lung isografts after long-term survival.

A high priority in organ transplantation research is to increase the number of hours that an organ can be successfully preserved. Transplant programmes rely on hypothermia and flush solutions to maintain organ viability during the storage period. We studied long-term morphology in lungs stored for 24 or 48 hours using two modified versions of University of Wisconsin solution, one mimicking the extracellular medium and the other the intracellular medium. Four weeks after transplantation, X-ray and angiograms were used to assess the proportion of ventilating tissue, and light and electron microscopy to analyse morphology. Pulmonary tissue presented near-normal histological appearance in well preserved areas while fibrosis and chronic inflammation were found in scarring processes. Electron microscopy studies revealed some damage-related changes in tissue which appeared histologically normal. Four weeks after transplantation, quality and quantity of recovery were uniform for both solutions tested after 24 hours of storage. However, without reaching significance, after 48 hours the quantity of successfully preserved pulmonary tissue was greater in the group stored in the intracellular solution.

Animals↗
PubMed1995

A radical view of the stomach: the role of oxygen-derived free radicals and anti-oxidants in gastroduodenal disease.

Following the discovery of Helicobacter pylori, the last decade has seen major advances in our understanding of gastroduodenal disease. However, our knowledge remains incomplete and the exact mechanism by which H. pylori causes inflammation and ulceration is still not known. The role of H. pylori in relation to other well known risk factors for gastroduodenal disease such as diet, smoking and the use of non-steroidal anti-inflammatory drugs is also unclear. Free radicals are highly toxic chemical species and evidence presented in this review suggests that they play an important role in the pathophysiology of gastroduodenal disease caused by many risk factors, including H. pylori. Dietary antioxidant deficiency may be a major factor in the development of gastric cancer and may exacerbate the carcinogenesis of nitrosamines. Antioxidant deficiency, either dietary or secondary to increased requirements as in smoking, may be a factor in the development of disease following H. pylori infection. The time now appears to be ripe for studies of novel antioxidant therapeutic strategies for gastroduodenal disease.

Animals↗
PubMed1995

Monitoring of surface mitochondrial NADH levels as an indication of ischemia during liver isograft transplantation.

Ischemia-reperfusion injury is a major cause of transplant dysfunction. One feature of this damage is mitochondrial dysfunction. The objective of this study was to determine whether surface fluorometric measurements of mitochondrial NADH can be made, and if the technique can detect differences in mitochondrial respiration between minimally stored 1 to 2 degrees C for 25 minutes (group 1, control) transplanted livers and those stored in hypertonic citrate at 1 to 2 degrees C (group 2) for 24 hours before transplantation. Measurements were made in livers isografted in 20 male Lewis rats. The technique is sufficiently sensitive to detect increased (nicotinamide-adenine dinucleotide (NADH) during dissection of hepatic vessels before ligation 0.52 +/- 0.04 (n = 14, P < .03) compared with the in situ exposed liver, 0.43 +/- 0.02 n = 14). Complete hepatic ligation resulted in a significant increase in NADH (1.22 +/- 0.10, n = 14), P < .0001) compared with hepatic artery ligation, which did not increase NADH levels. After storage, NADH levels increased (P < .02) but there was no significant difference between groups. In group 1, completion of portal vein (PV), suprahepatic vena cava (SVC), and descending vena cava anastomoses resulted in decreased NADH levels toward those after preparation of the vessels before ligation. However, there was a significant difference (P < .004) between the 25-minute and the 24-hour stored livers, 0.56 +/- 0.07 versus 0.23 +/- 0.04, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effects of hypothermic storage on the vascular endothelium: a scanning electron microscope study of morphological change in human vein.

OBJECTIVE: The aims of this study were: i) to identify morphological changes occurring in the endothelium of human umbilical veins subjected to the typical storage procedures used in transplantation and ii) to determine the relative efficacy of preservation solutions containing intra and extracellular levels of sodium and potassium. EXPERIMENTAL DESIGN: Prospective. PROCEDURE: Scanning electron micrographs were taken pre and post cold hypoxic storage of human umbilical veins for 3 or 16 hours. RESULTS: Cold preservation resulted in severe cell detachment with subsequent loss of monolayer continuity and exposure of thrombogenic basal membrane components (highly significant after only 3 hours of cold storage, Kruskal-Wallis, p < 0.01). The morphological alterations culminated in EC with spherical shapes. Cytoplasmic membranes presented an increased number of microvilli and intercellular processes, followed by microvillous swelling and surface blebbing as damage increased. Bleb detachment was seen in severely damaged specimens. However, morphological preservation was not significantly affected by the duration of hypoxia or the ionic balance of the solution tested. CONCLUSIONS: The present results demonstrate that even short periods (3 hours) of cold storage without revascularization cause significant morphological damage to the endothelium. The ionic composition of the preservation solution did not significantly affect the process. The morphological changes seen in this study could explain storage-related problems such as loss of normal vascular permeability and increased thrombogenicity, problems often associated with transplantation procedures.

Cryopreservation↗
PubMed1994

Inhibition of leukotriene B4 synthesis does not prevent development of acute renal failure following storage and transplantation.

Compound BW B70C, a selective 5-lipoxygenase inhibitor was tested for its ability to reduce inflammatory damage in an in vivo rabbit model of renal storage and transplantation. Kidneys were stored at 0-2 degrees C for 48 hr prior to autografting. In controls, renal vein LTB4 levels rose significantly after 30 min reperfusion but fell after 2 hr to baseline. TxB2 levels remained at baseline for the 6 hr measured. 6-k-PGF1 alpha levels rose significantly after 1 hr of reperfusion and remained elevated thereafter. Histology after 6 hr reperfusion showed moderate-to-severe cortical edema and mild congestion. Infused colloidal carbon was retained in the perivascular area in a narrow band at the corticomedullary junction, indicating a zone of vascular permeability. At 3 days after transplant, kidneys exhibited widespread tubular necrosis and calcification but little inflammation. Serum creatinine and urea peaked between days 3 and 5. 3/6 rabbits showed no symptoms of renal failure after 3 weeks. Pretreatment with BW B70C prevented the increase in LTB4 but had little effect on TxB2 and 6-k-PGF1 alpha levels. Histology showed no amelioration of cortical edema at 6 hr and congestion and hemorrhage were exacerbated. BW B70C had no effect on either colloidal carbon retention or distribution but did significantly reduce tubular necrosis and calcification at day 3. There was very little inflammatory infiltrate. BW B70C treatment did not improve the long-term viability of transplanted kidneys: 2/6 rabbits showed no symptoms of renal failure after 3 weeks. These data indicate that inhibition of LTB4 synthesis by BW B70C does not prevent the development of acute renal failure following 48 hr hypothermic storage and transplantation.

Acute Kidney Injury↗
PubMed1994

Metabolic and inflammatory responses after open or laparoscopic cholecystectomy.

Metabolic and inflammatory responses and changes in fatigue were studied in groups of patients undergoing either laparoscopic (n = 14) or open (n = 10) elective cholecystectomy. The mean(s.e.m.) cortisol concentration was significantly (P < 0.001) increased from 342(80) and 424(91) nmol l-1 before operation to 895(46) and 966(53) nmol l-1 after surgery in patients undergoing laparoscopic and open cholecystectomy respectively. There was no difference in cortisol response between the groups. Glucose concentration was increased (P < 0.02) at the end of surgery from mean(s.e.m.) preoperative levels of 5.54(0.15) and 6.16(0.15) mmol l-1 to postoperative values of 7.46(0.29) and 8.46(0.86) mmol l-1 for the laparoscopic and open procedures respectively. The mean glucose concentration during the initial 12 h after surgery was significantly greater (P < 0.02) following open than laparoscopic cholecystectomy. The mean(s.e.m.) albumin concentration fell significantly (P < 0.01) during surgery by an equivalent extent from 38.9(0.77) and 38.5(1.10)g l-1 to 35.2(0.79) and 34.6(0.97) g l-1. The mean (95 per cent confidence interval) interleukin (IL)6 concentration peaked 4 h after surgery at 57.2 (44.6-73.4) pg ml-1 following laparoscopic and 99.3 (72.8-135.4) pg ml-1 after open cholecystectomy. Mean (95 per cent confidence interval) C-reactive protein (CRP) levels at 24 h were 17.0 (12.7-21.2) and 49.0 (25.3-93.6) mg l-1 and at 48 h 28.0 (21.4-35.4) and 70.0 (36.4-133.6) mg l-1 following laparoscopic and open operations. The differences in IL-6 and CRP level between the groups were significant (P < 0.01). Mean(s.e.m.) fatigue scores were significantly (P < 0.05) increased from preoperative values of 2.4(0.24) and 2.6(0.44) to 5.5(0.56) and 6.8(0.51) at 24 h after laparoscopic and open operations. At 48 h the mean(s.e.m.) fatigue score (5.6(0.57)) remained significantly (P < 0.05) raised only after open cholecystectomy. Hand grip strength was significantly (P < 0.05) reduced only after the open procedure, to a mean(s.e.m.) of 88(6) per cent of the preoperative value. These results demonstrate that aspects of the metabolic and acute-phase responses are attenuated following laparoscopic cholecystectomy, consistent with a reduction in tissue trauma.

Blood Glucose↗
PubMed1994

Cold (0 degree C) ischaemic tolerance of latissimus dorsi free flaps in rats: a macroscopic and morphological study.

The purpose of this study was to define the cold (0 degree C) ischaemic tolerance (CIT) of the latissimus dorsi free flap in inbred rats. Flaps were isolated, stored at 0 degree C for periods of time ranging from 0 to 120 hr and then revascularised and reperfused for 14 days. Thereafter the CIT was assessed macroscopically, and by light microscopy. Electron microscopy was performed in flaps after 0 and 24 hr of reperfusion following a cold ischaemic interval ranging from 0 to 120 hr. From this preliminary study, it was concluded that the CIT was 48-72 hr.

Animals↗
PubMed1994

Liver metabolism in cold hypoxia: a comparison of energy metabolism and glycolysis in cold-sensitive and cold-resistant mammals.

The effects of cold hypoxia were examined during a time-course at 2 degrees C on levels of glycolytic metabolites: glycogen, glucose, glucose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, phosphoenolpyruvate, pyruvate, lactate and energetics (ATP, ADP, AMP) of livers from rats and columbian ground squirrels. Responses of adenylate pools reflected the energy imbalance created during cold hypoxia in both rat and ground squirrel liver within minutes of organ isolation. In rat, ATP levels and energy charge values for freshly isolated livers were 2.54 mumol.g-1 and 0.70, respectively. Within 5 min of cold hypoxia, ATP levels had dropped well below control values and by 8 h storage, ATP, AMP, and energy charge values were 0.21 mumol.g-1, 2.01 mumol.g-1, and 0.17, respectively. In columbian ground squirrels the patterns of rapid ATP depletion and AMP accumulation were similar to those found in rat. In rat liver, enzymatic regulatory control of glycolysis appeared to be extremely sensitive to the decline in cellular energy levels. After 8 h cold hypoxia levels of fructose-6-phosphate decreased and fructose-1,6-bisphosphate increased, thus reflecting an activation of glycolysis at the regulatory step catalysed by phosphofructokinase fructose-1,6-bisphosphatase. Despite an initial increase in flux through glycolysis over the first 2 min (lactate levels increased 3.7 mumol.g-1), further flux through the pathway was not permitted even though glycolysis was activated at the phosphofructokinase/fructose-1,6-bisphosphatase locus at 8 h, since supplies of phosphorylated substrate glucose-1-phosphate or glucose-6-phosphate remained low throughout the duration of the 24-h period.(ABSTRACT TRUNCATED AT 250 WORDS)

Acclimatization↗
PubMed1994

Free sensate secondary skin flaps: an experimental study on patterns of reinnervation and neovascularisation.

The main purposes of the present study were: 1) to compare differences, if any, in the patterns of reinnervation between secondary skin flaps, created either from "innervated skin grafts" or from ordinary denervated skin grafts; 2) to examine the influence of time, and the possible roles of granulation tissue and fibrosis in reinnervation following implantation of a nerve trunk into a secondary skin flap at different stages; and 3) to compare neovascularisation before and after free transfer of these flaps. Neurovascular changes were studied in a rat model by microangiography and by immunohistochemical techniques, using antisera to protein gene product 9.5 (panneural marker), to calcitonin gene-related peptide (sensory neurones) and to von Willebrand Factor (endothelial cell marker). The results indicate a potential clinical role for secondary sensate skin flaps where conventional methods of reconstruction including free neurovascular flap transfers are not available.

Animals↗
PubMed1994

An animal model to study the significance of dermis for grafting cultured keratinocytes on full thickness wounds.

Autologous cultured keratinocytes grafted onto full thickness wounds take poorly, and any epidermal cover that is produced is unstable. However, a more stable epidermis has been reported when keratinocytes are grafted onto a dermal surface. We have developed a skin grafting model using a polytetrafluoroethylene (PTFE) skin graft chamber in the domestic pig. The chambers isolate individual wounds and prevent epithelial migration from the wound edge. Dermal grafts were prepared by enzymatic separation of the epidermis from split skin to leave a de-epidermalized dermis (DED). Full thickness wounds were initially grafted with autologous DED and, subsequently, 7 days later with cultured autologous keratinocytes. The wounds were biopsied serially over 6 weeks, and processed for histology, immunocytochemistry and electron microscopy. Clinically, the grafts were seen to mature over the 6-week period. In 14/20 wounds, 40-72 per cent of the wound areas (as assessed by image analysis) had acquired epidermal cover at day 14. In 6/20 wounds, the epidermal cover was 0-27 per cent. The skin surface was stable at day 21. At this time electron microscopy and immunohistochemistry demonstrated a continuous, well formed basement membrane. The epidermis was initially acanthotic, but was histologically mature by day 14. Surprisingly, the dermal grafts were broken down by day 14. However, a neodermis formed beneath all areas with epithelial cover 21 days after grafting the keratinocytes. In this model, we have demonstrated the advantage of providing a dermal bed for cultured keratinocytes.

Animals↗
PubMed1994

Non-invasive measurement of respiratory chain dysfunction following hypothermic renal storage and transplantation.

Ischemia/reperfusion (IR) damage is a major cause of dysfunction in transplanted organs. The objective of the present study was to correlate in vivo measurements of respiratory chain (RC) function with histological and physiological parameters. Non-invasive in situ (surface fluorescence) measurements of mitochondrial NADH and near infrared spectroscopic measurements of cyt aa3 were made in unstored (Group 1) and 72 hour stored (1 to 2 degrees C) (Group 2) autografted rabbit kidneys. The effect of sodium pentobarbitone on NADH levels was investigated. In Group 1, there was a significant change in the redox state of cyt aa3 in all (N = 6) kidneys on reperfusion which correlated with organ viability and increased NADH oxidation and minimal edema on histological examination. In Group 2 there was no significant change in cyt aa3 compared to baseline, and this correlated with poor long term organ viability, slower NADH oxidation, and severe cortical edema. Pentobarbitone inhibition of the RC resulted in rapid and complete reduction of NAD+ in Group 1, but none or only a slight reduction in Group 2. The results demonstrate that it might be possible in future to predict organ viability and histological changes by non-invasive measurements of RC dysfunction in the clinical transplant situation.

Animals↗
PubMed1994

Regulation of c-jun expression during hypoxic and low-glucose stress.

Hypoxic stress in tumor cells has been implicated in malignant progression and in the development of therapeutic resistance. We have investigated the effects of acute hypoxic exposure on regulation of the proto-oncogene c-jun in SiHa cells, a human squamous carcinoma cell line. Hypoxic exposure produced increased levels of c-jun mRNA resulting from both message stabilization and transcriptional activation. A superinduction of c-jun message resulted during simultaneous oxygen and glucose deprivation, with several characteristics of an induction mediated by oxidative-stress pathways. This superinduction was blocked by preincubation of cells with the glutathione precursor N-acetyl cysteine or with phorbol 12-myristate 13-acetate, which indicates redox control of c-jun expression and probable involvement of protein kinase C. By gel retardation assay, no increase in AP-1 DNA binding activity was found to be concomitant with the transcriptional activation of c-jun. A lack of increased DNA binding was observed for the consensus AP-1 sequence and for the two AP-1 sequence variants found within the c-Jun promoter. Additionally, hypoxic and low-glucose stress produced no activation of stably transfected AP-1 reporter sequences. Taken together, these results indicate that the transcriptional activation of c-jun during hypoxic and low-glucose stress involves redox control and is unlikely to be mediated by AP-1 recognition elements within the c-jun promoter.

Acetylcysteine↗
PubMed1994

Angiogenesis and reinnervation in skin flaps: the effects of ischaemia examined in an animal model.

In clinical flap transplantation, ischaemia may alter reinnervation patterns either directly or by affecting angiogenesis. This study presents the effects of ischaemia on innervation in totally denervated, transiently (30 minutes) or prolongedly ischaemic skin flaps studied immunohistochemically with antisera to PGP 9.5, CGRP and VWF. Following transient ischaemia, an increase in PGP-immunoreactive (PGP-IR) and CGRP-IR nerve fibres in distant skin by day 12 was followed by increased innervation in immediately adjacent skin. The latter increase was maintained up to 24 days which allowed near normal innervation at the suture margin and in adjacent flap tissue, 0.5 cm from the margin. There was concomitant reinnervation from the pedicle by day 24. In prolongedly ischaemic flaps, an earlier and more prolonged increase in innervation was seen in the entire surrounding skin, with innervation around the suture line at 24 days resembling that in the transiently ischaemic flaps despite initial complete nerve fibre depletion in this area. Hypertrophic nerve fibre clusters were seen in fibrotic areas overlying the pedicle. Vascular changes were similar in both groups with vascularization preceding reinnervation. There were no significant differences in reinnervation between the transiently and prolongedly ischaemic flaps at 24 days, despite considerable initial variations. Ischaemia, CGRP, mediators of chronic inflammation and epidermal factors appeared to stimulate angiogenesis and reinnervation.

Animals↗
PubMed1994

GRATEFUL MED.

Explore the source record for details and available documents.

Grateful Med↗
PubMed1993

Reoxygenation following hypoxia stimulates lipid peroxidation and phosphatidylinositol breakdown in kidney cortical slices.

Reoxygenation of hypoxic (120 min at 37 degrees) rabbit kidney cortical slices in vitro resulted in a rapid increase in lipid peroxidation and phosphatidylinositol hydrolysis. No changes in phosphatidylinositol breakdown occurred during hypoxia or upon reoxygenation in the absence of calcium. Incubation of renal slices with carbon tetrachloride resulted in increased lipid peroxidation but had no effect on phosphatidylinositol breakdown. It is concluded that altered intracellular calcium homeostasis during reoxygenation is involved in mediating increased phosphatidylinositol hydrolysis through activation of a specific phospholipase C, but that oxidative stress per se does not have a significant effect on the inositol phosphate secondary messenger response in this model system.

Animals↗
PubMed1993

Neither desferrioxamine nor lipoic acid enhances the cold ischaemic tolerance of epigastric free flaps in rats.

This study was designed to test the ability of pre- and postischaemic administration of desferrioxamine (DFX), a combination of a preischaemic single passage perfusion with hypertonic citrate solution (HCA) and postischaemic administration of DFX, and pre- and postischaemic administration of lipoic acid (LA) to enhance the cold (0 degree C) ischaemia tolerance in epigastric free flaps in inbred rats. The ischaemic intervals varied between 0 and 120 hr. The area of flap survival 2 weeks after revascularisation as a percentage of original flap size was recorded as an exponent of ischaemic tolerance. None of the treatment regimens was able to increase flap area survival. Histologically, there were no major differences between the different treatment regimens.

Adipose Tissue↗