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E E Tredget

Publications and source records attributed to E E Tredget.

At least 73 records · Page 4Linked to original sources
PubMed1993

Enhanced expression of mRNA for transforming growth factor-beta, type I and type III procollagen in human post-burn hypertrophic scar tissues.

To explore the possible role of locally synthesized transforming growth factor beta-1 (TGF-beta 1) and procollagen gene expression in postburn hypertrophic scars, we have compared mRNA levels for type I and type III procollagen and TGF-beta 1 in human hypertrophic scar tissue with normal dermis obtained from the same patients as a control. Northern blot analysis of total RNA extracted from hypertrophic scar tissue and normal skin demonstrated two transcripts for the pro-alpha 1(I) chain (5.8 kb and 4.8 kb) and for the pro-alpha 1(III) chain (5.4 kb and 4.8 kb) and one transcript (4.9 kb) for TGF-beta 1. Quantitative analysis of dot blot autoradiograms of mRNA from three samples of hypertrophic scar tissue and normal skin showed average increases of 102% (p < 0.05) for pro-alpha 1(I), 91% (p < 0.06) for pro-alpha 1(III), and 61% (p < 0.05) for TGF-beta 1. Three additional hypertrophic scar samples were quantitatively analyzed on Northern blots and showed increases of 246%, 102%, and 250% of the specific messages for pro-alpha 1(I), pro-alpha 1(III), and TGF-beta 1 relative to a normal skin control. Two transcripts (4.9 kb and 2.5 kb) for TGF-beta 1 were identified in cultured fibroblasts. In contrast to the results from tissue, the level of these transcripts in fibroblasts cultured from hypertrophic scar tissue and normal skin were not significantly different, suggesting that the synthesis of this growth factor is stimulated in tissue by a presently unknown mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Profile of the paediatric burn patient in a Canadian burn centre.

Five hundred and eighty-three children (0-18 years old), consisting of 33.4 per cent of all burn inpatients, were admitted to the University of Alberta Hospitals over an 11-year period (January 1978 to December 1988). Demographic and outcome variables, in addition to aetiological factors, were examined. 48.4 per cent of burns occurred in children less than 4 years of age, with males predominating in every age group (P less than 0.001). Children had smaller burns, a higher incidence of scalds, less inhalation injuries and a lower mortality compared to adult burn patients admitted over the same time period (P less than 0.05). There was a low incidence of confirmed child abuse by burns (1.4 per cent). High-risk environments identified were the home (74.6 per cent of burns) and recreational settings (12.4 per cent of burns), mainly occurring around campfires. Native children were overrepresented in the burn population compared to the general population by a factor of approximately 10:1. Scald prevention, high-risk environments (home and recreational), high-risk populations (male and natives) and unsafe practices with flammable liquids (petrol in particular) should be emphasized in paediatric burn prevention programmes.

Accidents, Home↗
PubMed1992

Epidemiology of infections with Pseudomonas aeruginosa in burn patients: the role of hydrotherapy.

Pseudomonas aeruginosa remains a cause of serious wound infection and mortality in burn patients. By means of restriction fragment length polymorphism analysis and a DNA probe for the pilin gene of Pseudomonas, a lethal strain of nosocomial P. aeruginosa was identified as the cause of an outbreak of wound infections among burn patients. Environmental surveys suggested an association of the outbreak with hydrotherapy provided to many patients in a common facility. In a trial of burn wound care without hydrotherapy, overall mortality was reduced significantly, mortality associated with pseudomonas sepsis was eliminated, and the strain of P. aeruginosa associated with earlier mortality was eradicated. Moreover, fewer nosocomial pseudomonas infections, lower levels of pseudomonas resistance to aminoglycoside antibiotics, significantly fewer pseudomonas infections of skin graft donor sites, and later appearance of Pseodomonas species in burn patients were found during the period when hydrotherapy was not used.

Adolescent↗
PubMed1991

Recombinant human erythropoietin for a Jehovah's Witness with anemia of thermal injury.

We report the use of recombinant human erythropoietin (rh-Ep) as an alternative to transfusion therapy in a burn victim who was a Jehovah's Witness and refused blood transfusion. Despite endogenous elevated erythropoietin levels, the patient was reticulocytopenic and administration of rh-Ep was accompanied by a 10-fold increase in reticulocyte response and a rise in hemoglobin from 7.4 to 10.4 g/dl over a 12-day period. We suggest that the exogenously administered erythropoietin overcame a clinically inadequate endogenous erythropoietin response.

Anemia↗
PubMed1990

Determination of 4-hydroxyproline in collagen by gas chromatography/mass spectrometry.

Derivatization of 4-hydroxyproline (Hyp) in collagen using trifluoroacetylation and methanol esterification produces two derivatives when analyzed by gas chromatography/mass spectrometry (GC/MS). The diacyl derivative N,O-bis(trifluoroacetyl)-4-hydroxy-L-proline methyl ester (N,O-TFA-Hyp) formed in this manner has a shorter retention time and different fragmentation pattern by GC/MS as compared to the slower eluting monoacetylated species N-trifluoroacetyl-4-hydroxy-L-proline methyl ester (N-TFA-Hyp). By selected ion monitoring of the appropriate ions of either N,O-TFA-Hyp (m/z 164, 278) or N-TFA-Hyp (m/z 164, 182) efficient quantitation of Hyp in collagen is possible within the broad range of 5-1000 ng with a lower limit of detection of 0.5 ng per injection. Measurement of 18O2 incorporation into collagen is possible by selected ion monitoring of the m/z 182 ion formed only from the monoacetylated derivative, N-TFA-Hyp, produced by methanol solvolysis of the N,O-TFA-Hyp derivative, as proposed herein.

Acetic Anhydrides↗
PubMed1990

The role of inhalation injury in burn trauma. A Canadian experience.

From 1977 to 1987, 1705 thermally injured patients were admitted to the Firefighters' Burn Center at the University of Alberta Hospitals. Thirteen hundred forty-four were male (78.8%) and 361 were female (21.2%), with a mean total burn surface area (TBSA) of 15.1 (SEM +/- 0.4%) and a range of 1% to 99% TBSA. Sixteen hundred thirty-five patients survived to be discharged from hospital, with an overall survival rate of 95.9%. One hundred twenty-four burn patients (7.3%) suffered concomitant inhalation injury diagnosed by bronchoscopy. Patients with inhalation injury suffered from larger TBSA (39.7% +/- 2.8% versus 12.2% +/- 0.3%; p less than 0.01) than those without inhalation injury. Inhalation injury increased the number of deaths from burn injury (34.7% versus 1.7%; p less than 0.01) independent of age and TBSA. Inhalation injury was associated with a threefold prolongation of hospital stay (23.7 +/- 0.7 versus 74.4 +/- 6.2 days; p less than 0.01) and was independent of age and TBSA. Multifactorial probit analysis was performed for both inhalation- and noninhalation-injured burned patients to allow TBSA and age adjusted rates of mortality for the burn population presented. The maximum detrimental effects of inhalation injury in burn patient outcome occurred when it coexisted with moderate (15% to 29% TBSA) to large (30% to 69% TBSA) thermal injuries. These data demonstrate that inhalation injury is an important comorbid factor in burn injury that increases the number of deaths substantially. Most importantly such injuries also independently prolong the duration of hospitalization in a highly unpredictable fashion as compared to patients with cutaneous burns only. As such our data illustrate the extreme importance of inhalation injury as a comorbid factor following thermal injury and reveal the present limitations for accurate quantification of the magnitude of respiratory tract injury accompanying thermal trauma.

Adolescent↗
PubMed1990

Quantitative role of splanchnic region in leucine metabolism: L-[1-13C,15N]leucine and substrate balance studies.

The role of the splanchnic region (Sp) in whole body leucine metabolism was assessed in six chronically catheterized fasting mongrel dogs and in eight dogs during constant enteral feeding of a complete amino acid solution (0.24 g.kg-1.h-1). We used primed continuous intravenous infusions of L-[1-13C,15N]leucine and L-[1-14C]leucine and measurements of arteriovenous isotope and leucine balance across the gut, liver, and Sp. In the fasted condition, 3.5% of arterial leucine supply was oxidized in the Sp, accounting for 13% of total body leucine oxidation, with 10% by liver. With amino acid feeding 1) leucine carbon and nitrogen fluxes and oxidation were increased (P less than 0.01) at the whole body level; 2) the percent of whole body leucine oxidation occurring in the Sp and liver increased (P less than 0.01) to 41 and 27%, respectively; 3) fractional metabolic utilization of leucine delivered to the Sp was reduced (P less than 0.01) from 47 to 35%; 4) the deamination rate of leucine in the gut was increased (P less than 0.05), along with an increased reamination rate of alpha-ketoisocaproic acid in the Sp (P less than 0.05). These findings reveal that the Sp accounts for a small fraction of whole body leucine oxidation during the fasting condition, but it plays a quantitatively important role in total body leucine oxidation during amino acid feeding; the gut and liver play cooperative roles in controlling leucine supply to peripheral tissues.

Animals↗
PubMed1990

Update on trauma care in Canada. 1. Recent advances in thermal injuries.

Thermal injury frequently occurs in traumatized patients in North America and causes serious morbidity and mortality, predominantly to children and young adults. Over the past decade, considerable technologic advances have improved survival after burn injury. Ongoing research coupled with current surgical advances in equipment, technique, early wound closure and alternative forms of wound coverage offer the potential for greater survival with enhanced quality of life for traumatized patients with burn injuries. However, sepsis and inhalation injury remain important ongoing causes of death, for which the understanding and solutions appear to be unfolding as research into the multisystem effects of the inflammatory process continues.

Adolescent↗
PubMed1988

Role of interleukin 1 and tumor necrosis factor on energy metabolism in rabbits.

A study of the combined effects of intravenous infusion of the recombinant cytokines beta-interleukin 1 (IL-1) and alpha-tumor necrosis factor (TNF) on energy substrate metabolism in awake, conditioned, adult rabbits was performed. After a 2-h basal or control period, 48-h fasted rabbits were administered TNF and IL-1 as a bolus (5 micrograms/kg) followed by a continuous intravenous infusion (25 ng.kg-1.min-1) for 3 h. Significant increases in plasma lactate (P less than 0.01), glucose (P less than 0.01), and triglycerides (P less than 0.05) occurred during the combined infusion of IL-1 and TNF, whereas neither cytokine alone had no effect. There was a 33% increase in the rate of glucose appearance (P less than 0.05), but glucose clearance was not altered compared with the control period. Glucose oxidation increased during the combined cytokine infusion period and glucose recycling increased by 600% (P less than 0.002). Lactic acidosis and decreased oxygen consumption, as a result of the cytokine infusions, indicated development of anaerobic glycolytic metabolism. A reduction in the activity state of hepatic mitochondrial pyruvate dehydrogenase (65 vs. 82% in control animals, P less than 0.05) was consistent with the observed increase in anaerobic glycolysis. Thus the combined infusion of IL-1 and TNF in rabbits produces metabolic manifestations seen in severe injury and sepsis in human patients and, as such, may account for the profound alterations of energy metabolism seen in these conditions.

Animals↗
PubMedDate not supplied

Keratinocyte differentiation inversely regulates the expression of involucrin and transforming growth factor beta1.

Extensive skin loss from a variety of conditions such as severe thermal injury is associated with significant functional morbidity and mortality. In recent years, the healing quality has been improved for patients who suffer burns due in part to the usage of skin replacement mainly prepared from multi-layered sheets of cultured keratinocytes. Although it is known that keratinocytes are a rich source of wound healing promoting factors such as transforming growth factor-beta1 (TGF-beta1), it is not clear whether differentiated keratinocytes in a multi-layer form release this multi-functional growth factor and has any functional influence on dermal fibroblasts. This study examined the hypothesis that keratinocytes in mono- and multi-layer forms express different levels of TGF-beta1. To address this hypothesis, keratinocytes were grown in serum free medium (KSFM) supplemented with bovine pituitary extract (50 microg/ml) and EGF (5 microg/ml). When cells reached confluency, conditioned medium was removed and replaced with 50% KSFM with no additives and 50% DMEM without serum and cells were allowed to form multi-layers and differentiate. The conditioned medium was then collected every 48 h up to 24 days and the level of TGF-beta1 and the efficacy of a keratinocyte released fibroblast mitogenic factor were evaluated by ELISA and (3)H-thymidine incorporation, respectively. Northern analysis was also employed to evaluate the expression of TGF-beta1, involucrin, TIMP-1, and 18 S ribosomal RNA in keratinocytes at different times of the onset of differentiation. The microscopic morphology of keratinocytes at different times of induction of cell differentiation showed detachments (nodules) of many regions of keratinocyte sheet from culture substratum within 1-2 weeks. The numbers and sizes of these nodules were increased as the process of keratinocyte differentiation proceed. The results of TGF-beta1 evaluation revealed that mono-layers of cultured keratinocytes which were round, attached, and proliferating in KSFM + BPE and EGF containing medium released a significantly higher level of TGF-beta1 (196 +/- 58 pg /ml) relative to those grown in multi-layer forms (28 +/- 7.8 pg/ml). A longitudinal experiment was then conducted and the results showed that cells on the onset of differentiation released even greater level of TGF-beta1 (388 +/- 53 pg/ml) relative to those grown in KSFM + BPE and EGF. This finding was consistent with the expression of TGF-beta1 mRNA evaluated in keratinocytes grown in test medium for various duration. In general, the level of TGF-beta1 protein and mRNA gradually reduced to its lowest level within 12 days of growing cells in our test medium. When aliquots of the collected keratinocyte conditioned medium were added to dermal fibroblasts, the level of (3)H-thymidine incorporation increased only in those cells receiving aliquots of conditioned medium containing high levels of TGF-beta1. When involucrin was used as a differentiation marker for keratinocytes at different time points, the highest level of involucrin mRNA expression was found at the later stage of cell differentiation. In conclusion, high involucrin expressing differentiated keratinocytes seem to be quiescent in releasing both TGF-beta1 and a fibroblast mitogenic factor.

Biomarkers↗
PubMedDate not supplied

The metabolic effects of thermal injury.

Major thermal injury is associated with extreme hypermetabolism and catabolism as the principal metabolic manifestations encountered following successful resuscitation from the shock phase of the burn injury. Substrate and hormonal measurements, indirect calorimetry, and nitrogen balance are biochemical metabolic parameters which are useful and more readily available biochemical parameters worthy of serial assessment for the metabolic management of burn patients. However, the application of stable isotopes with gas chromatography/mass spectroscopy and more recently, new immunoassays for growth factors and cytokines has increased our understanding of the metabolic manifestations of severe trauma. The metabolic response to injury in burn patients is biphasic wherein the initial ebb phase is followed by a hypermetabolic and catabolic flow phase of injury. The increased oxygen consumption/metabolic rate is in part fuelled by evaporative heat loss from wounds of trauma victims, but likely also by a direct central effect of inflammation upon the hypothalamus. Although carbohydrates in the form of glucose appear to be an important fuel source following injury, a maximum of 5-6 mg/kg/min only is beneficial. Burn patients have accelerated gluconeogenesis, glucose oxidation, and plasma clearance of glucose. Additionally, considerable futile cycling of carbohydrate intermediates occurs which includes anaerobic lactate metabolism and Cori cycle activity arising from wound metabolism of glucose and other substrates. Similarly, accelerated lipolysis and futile fatty acid cycling occurs following burn injury. However, recent evidence suggests that lipids in the diet of burned and other injured patients serve not only as an energy source, but also as an important immunomodulator of prostaglandin metabolism and other immune responses. Amino acid metabolism in burn patients is characterized by increased oxidation, urea synthesis, and protein breakdown which is prolonged and difficult to reduce with current nutritional therapy. However, the current goal of nutritional support is to optimize protein synthesis. Specific unique requirements may exist for supplemental glutamine and arginine following burn injury but further research is needed before enhanced branched chain amino acids supplements can be recommended for burn patients. Recent research investigations have revealed the importance of enteral feeding to enhance mucosal defense against gut bacteria and endotoxin. Similarly, research has demonstrated that many of the metabolic perturbations of burns and sepsis may be due, at least in part, to inflammatory cytokines. Investigation of their pathogenesis and mechanism of action both at a tissue and a cellular level offer important prospects for improved understanding and therapeutic control of the metabolic disorders of burn patients.

Amino Acids, Branched-Chain↗
PubMedDate not supplied

Interferons gamma and alpha-2b differentially regulate the expression of collagenase and tissue inhibitor of metalloproteinase-1 messenger RNA in human hypertrophic and normal dermal fibroblasts.

We have recently shown that both interferon gamma (gamma) and interferon alpha-2b (alpha-2b) markedly depress the expression of messenger RNA for type I procollagen and fibronectin in postburn hypertrophic scar and normal dermal fibroblasts. In this article we examine the effects of these cytokines on the expression of mRNA for collagenase and its natural inhibitor, tissue inhibitor of metalloproteinase-1. Twelve different fibroblast cell strains, six from postburn hypertrophic scar and six from the normal dermis of the same patients, were established in cell culture. The results of a dose response experiment showed increases in collagenase mRNA up to 4000 U/ml of interferon-alpha-2b, but maximal increases in tissue inhibitor of metalloproteinase mRNA expression and maximal decrease in mRNA for type I procollagen at 2000 U/ml. For subsequent experiments cells were treated with either interferon-alpha-2b (2000 U/ml) or -gamma (1000 U/ml) for 96 hours. Quantitative analysis showed increases in tissue inhibitor of metalloproteinase-1 and collagenase mRNA (81% and 54%, respectively) in interferon-alpha-2b-treated hypertrophic scar fibroblasts. Under the same experimental conditions, interferon-alpha-2b had similar effects on normal dermal fibroblasts; however, interferon-gamma had a differential effect on the expression of mRNA for collagenase and tissue inhibitor of metalloproteinase-1. Cells treated with interferon-gamma showed increases in tissue inhibitor of metalloproteinase-1 mRNA (78% in hypertrophic scar and 56% in normal dermal fibroblasts) but decreases (59% and 42%, respectively) in collagenase mRNA. These effects appear to be selective because rehybridization of blots with a complementary DNA for tissue inhibitor of metalloproteinase-2 mRNA showed no marked alteration in the abundance of this transcript. Significantly greater collagenase activity was found in conditioned medium from interferon-alpha-2b-treated hypertrophic scar cells compared with that from interferon-gamma-treated cells. These findings suggest that interferon alpha-2b would have some advantages over interferon-gamma for the treatment of dermal fibroproliferative disorders, such as postburn hypertrophic scar.

Journal Article↗
PubMedDate not supplied

Effect of interferon-alpha2b on guinea pig wound closure and the expression of cytoskeletal proteins in vivo.

Scar contraction following the healing of deep partial-thickness or full-thickness dermal injury is a leading cause of functional and cosmetic morbidity. The therapeutic use of interferon for the treatment of fibroproliferative disorders associated with scar contraction, including hypertrophic scar, has been suggested because of its antifibrotic properties. Treatment of fibroblasts with interferon has been shown to reduce the rate and extent of contraction using the in vitro fibroblast-populated collagen lattice model. In order to establish the effect of interferon-alpha2b on full-thickness wound contraction in vivo, osmotic pumps loaded with interferon or sterile saline were implanted intraperitoneally in guinea pigs. Seven days following implantation, six full-thickness punch biopsy wounds were created and were monitored by daily assessment of the wound. There was a significant reduction in the rate of wound contraction in the interferon-treated animals after day 3 (p < 0.01). Western blot analysis was used to quantitate selected cytoskeletal proteins in the normal skin and tissue biopsied from the wound at days 7, 14, and 21 postinjury. The amount of vimentin in the contracted wound increased following injury as compared with the amount present in normal skin (p < 0.0001); however, the relative amounts of the myofibroblast-associated cytoskeletal proteins alpha-smooth muscle actin and smooth muscle myosin were less than those found in normal, uninjured skin. By using vimentin to adjust the levels of cytoskeletal proteins for the increase in cellularity in the wounds, both alpha-smooth muscle actin and smooth muscle myosin significantly increased after closure of the wounds on day 14, as compared with the open-wound stage (day 7), before further reductions occurred with remodeling on day 21. Measurement of apoptotic cells using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay revealed an increase in apoptosis in the interferon-alpha2b-treated animals at 21 days following wounding (p < 0.001), which did not colocalize with alpha-smooth muscle actin staining. Taken together, these findings suggest that interferon-alpha2b inhibits wound contraction in vivo, not through an appreciable alteration in myofibroblast number or cytoskeletal protein expression, but possibly through a reduction in fibroblast cellularity by the induction of apoptosis.

Angiogenesis Inhibitors↗
PubMedDate not supplied

Hypertrophic scar tissues and fibroblasts produce more transforming growth factor-beta1 mRNA and protein than normal skin and cells.

Transforming growth factor-beta1 is a well-known fibrogenic cytokine produced by many types of cells including dermal fibroblasts. To investigate whether this fibrogenic cytokine is involved in development of hypertrophic scar, transforming growth factor-beta1 gene expression was evaluated in small skin samples. Because a sufficient quantity of normal skin from patients with hypertrophic scar is not readily available, a reverse transcription-polymerase chain reaction technique was used. Quantitation of gene expression by reverse transcription-polymerase chain reaction is difficult partly due to the lack of suitable complementary RNA standards. We have established a convenient, reliable procedure to construct an internal standard for transforming growth factor-beta1 starting with a gene specific polymerase chain reaction product. After digestion of the polymerase chain reaction product with endonuclease, a small piece of cDNA from human procollagen alpha1(I) cDNA with compatible ends was inserted into the polymerase chain reaction-DNA fragment. The recombinant cDNA was re-amplified by polymerase chain reaction and subcloned into a plasmid containing bacteriophage T7 and T3 promoters. Complementary RNA was prepared from the recombinant plasmid and amplified by reverse transcription-polymerase chain reaction together with the tissue or cellular RNA. After amplification, the products were electrophoresed in an agarose gel containing ethidium bromide. The bands for internal standard and transforming growth factor-beta1 mRNA were scanned, digitized, and plotted against the amount of internal standard complementary RNA added in the reverse transcription-polymerase chain reaction. The number of mRNA molecules/cell was calculated. We examined the transforming growth factor-beta1 mRNA in hypertrophic scar tissue and in normal skin and found that hypertrophic scar tissues expressed five-fold more transforming growth factor-beta1 mRNA than normal skin per unit of wet weight. We used this procedure to quantitate transforming growth factor-beta1 mRNA expression in 5 pairs of fibroblast cultures derived from hypertrophic scar and normal skin. The results showed that hypertrophic scar fibroblast cultures contain significantly more molecules of mRNA for transforming growth factor-beta1 than normal cells (116 +/- 6 vs. 97 +/- 7, p = 0.017, n = 5). These results were supported by Northern analysis for transforming growth factor-beta1 mRNA in the cells and enzyme-linked immunosorbent assay for TGF-beta1 protein in fibroblast-conditioned medium. In conclusion, hypertrophic scar tissue and fibroblasts produce more mRNA and protein for transforming growth factor-beta1, which may be important in hypertrophic scar formation. The construction of the gene specific internal standard for reverse transcription-polymerase chain reaction is a simple and reliable procedure useful to quantitate gene expression in a small amount of tissue or number of cells.

Biopsy, Needle↗
PubMedDate not supplied

Activation of latent transforming growth factor-beta1 is induced by mannose 6-phosphate/insulin-like growth factor-II receptor.

This study was conducted to further explore the mechanism of transforming growth factor beta1 (TGF-beta1) activation, which plays a critical role in many physiological and pathological conditions. We have previously shown that the large (270 kDa), but not small (40 kDa), mannose 6-phosphate receptors facilitate the cellular response to latent TGF-beta1 released from genetically modified cells. In this study, we explored the role of cell membrane associated transglutaminase and plasmin in mannose 6-phosphate receptor induced latent TGF-beta activation using MS and MS-9 cells bearing either no receptors or the 270 kDa mannose 6-phosphate/insulin-like growth factor II receptors, respectively. As a source of latent TGF-beta1, PA317 cells were transfected with either pLin-TGF-beta1 vector or pLin retroviral vector with no TGF-beta1 insert using calcium phosphate precipitation. The latency and bioactivity of TGF-beta1 in conditioned medium derived from transfected PA317 cells were evaluated by enzyme-linked immunosorbent assay and mink lung epithelial cell growth inhibition assay, respectively. The level of latent TGF-beta1 was 13-fold higher (20.1 +/- 0.4 vs. 1.5 +/- 0.03 ng/ml) in conditioned medium from pLin-TGF-beta1 transfected cells than that of control. The latency and bioactivity of TGF-beta1 released from pLin-TGF-beta1 transfected cells were confirmed by evaluation of 3H-thymidine incorporation in Mv1Lu epithelial cells treated with non- and heat-activated 10% conditioned medium. The results showed a significantly lower 3H-thymidine incorporation in Mv1Lu epithelial cells treated with heat-activated PA317 conditioned medium (4% of control) relative to those treated with either control or nonheated conditioned medium. This inhibition was abrogated by addition of 40 microg/ml of TGF-beta1 neutralizing antibody. The level of 3H-thymidine incorporation was then evaluated in MS-9 cells receiving Dulbecco's modified Eagle medium containing either 0% 10%, 30% or 50% volumes of nonactivated PA317 conditioned medium for 24 hours. The results showed a markedly lower proliferation in response to 30% and 50% conditioned medium used in MS-9 cells. Under similar experimental conditions, addition of only mannose 6-phosphate, but not fructose 6-phosphate or mannose 1-phosphate, at 1 mM concentration restored the MS-9 cell proliferative response to latent TGF-beta1. The inhibitory effects of latent TGF-beta1 on MS-9 cell proliferation were restored by addition of either TGF-beta1 neutralizing antibody or cystamine, a transglutaminase inhibitor. In contrast, addition of aprotinin, a plasmin inhibitor, had a marginal influence on inhibitory effects of latent TGF-beta1 on MS-9 cell proliferation. Interestingly, a mixture of latent TGF-beta1 + MS-9 cell membranes, but not MS cell membranes, also inhibited the mink lung epithelial cell proliferation (34% of control). These findings indicate that mannose 6-phosphate/insulin-like growth factor II receptors are involved in latent TGF-beta activation and that is at least partly dependent on cell membrane associated transglutaminase, but not on plasmin.

Animals↗
PubMedDate not supplied

Rating the resolving hypertrophic scar: comparison of the Vancouver Scar Scale and scar volume.

The increased focus of research interests and clinical documentation on outcomes demands that evaluation tools provide reliable and valid data. The Vancouver Scar Scale (VSS) was developed to provide a more objective measurement of burn scars; however, the validity (a test's ability to measure the phenomenon for which it was designed) of the VSS has not been tested. To examine the construct validity of the VSS, we compared it with scar volume, which has established face validity. Burn scars were evaluated monthly for a minimum of 7 months. Three scar volume measurements were performed on each scar. In addition, 3 independent examiners completed the VSS for the same scar. The data generated by these 2 measurements were used to establish the following: (1) the interrater agreement estimated by interclass correlation coefficient, (2) convergence validity, (3) the sensitivity of the assessments to discriminate changes in the scar over time, and (4) the prevalence of related parameters that are not currently being captured by the VSS. In an attempt to address some of the deficiencies of the VSS, we propose several modifications. We anticipate that these changes will increase the reliability and validity of the VSS through an increase in the awareness that training in the use of this scale is required, through improvement in the quality of the subscales, and through the documentation of additional pertinent information.

Burns↗
PubMedDate not supplied

A simple, effective system for assessing viability in split-thickness skin with the use of oxygen consumption.

To address the recognized need for better viability-assessment techniques in the banking of allograft skin, we have developed a simple, effective, and easily constructed system for measuring the aerobic activity in small skin samples. The system consists of a microcomputer interfaced to a Clark-type polarographic oxygen electrode to measure oxygen concentrations in discs (5 mm diameter) of split-thickness skin. The system allows simultaneous data acquisition and an on-screen display of oxygen readings on a linear or logarithmic scale. The computer program quantifies the rate of oxygen consumption by calculating a linear regression of oxygen measurements between 100 and 600 seconds. Data are stored in a standard format for easy transfer to commercial software packages for further analysis. The kinetics of oxygen consumption by porcine split-thickness skin stored at 4 degrees C for up to 21 days was assessed with this technique and showed a gradual decline in rate as function of storage time, reaching 50% recovery after 6 days. This assay is a simple and inexpensive method to establish and perform, thus making it suitable as a routine assay for use in the banking of skin and other tissues.

Animals↗