bluuebunny/crossref_metadata_2025 huggingface dataset:
Geomorphic Expression of Abrupt Climate Change in Southwestern North America at the Glacial Termination
Authors: Anderson Roger Y. , Allen Bruce D. , Menking Kirsten M.
Published: September 2002

Eolian and subaqueous landforms composed of gypsum sand provide geomorphic evidence for a wet episode at the termination of glacial climate in southwestern North America. Drying of pluvial Lake Estancia, central New Mexico, occurred after ca. 12,00014C yr B.P. Thereafter, eolian landforms on the old lake floor, constructed of gypsum sand, were overridden by rising lake water, modified by subaqueous processes, and organized into beach ridges along the lake's eastern shore. Preservation of preexisting eolian landforms in the shallow lake suggests abupt changes in lake level and climate. Available radiocarbon ages suggest that the final highstand recorded by beach ridges may have developed during the Younger Dryas (YD) stade. The beach ridges provide information about lake surface area, which was 45% of the lake area reached during the maximum highstands of the late Pleistocene. A similar proportional response has been reported for YD climate changes outside the North Atlantic region.
Tree-Ring-Based Spring Temperature Patterns over the Past Four Centuries in Western Himalaya
Authors: Yadav Ram R. , Singh Jayendra
Published: September 2002

A network of 12 tree-ring width chronologies of Himalayan cedar (Cedrus deodara) from the western Himalayan region, India, has been used to reconstruct mean spring (March–May) temperature variations back to A.D. 1600. The most conspicuous feature of the temperature reconstruction is the long-term cooling trend since the late 17th century that ended early in the 20th century. The warmest 30-yr mean for the 20th century was recorded during 1945–1974. However, this warming, in the context of the past four centuries is well within the range of natural variability, since warmer springs of greater magnitude occurred in the later part of the 17th century (1662–1691).
Consequences of reduced production of NO on vascular reactivity of porcine coronary arteries after angioplasty: importance of EDHF
Authors: Thollon Catherine , Fournet‐Bourguignon Marie Pierre , Saboureau Delphine , Lesage Ludovic , Reure Hélène , Vanhoutte Paul M , Vilaine Jean Paul
Published: September 2002

The consequences of the reduced production of nitric oxide (NO) by cells from regenerated endothelium were investigated by measuring membrane potential of smooth muscle cells (SMCs), isometric tension and cyclic nucleotides content in porcine coronary arteries with intimal thickening, four weeks following angioplasty.

Under basal conditions, SMCs of coronary arteries with regenerated endothelium were depolarized by 10 mV. This depolarization was associated with 82% decreased level of cGMP without alteration in cAMP.

Sodium nitroprusside (SNP, 1 μM) repolarized SMCs of the previously denuded coronary arteries. This repolarization was abolished by 1H‐[1,2,4]‐oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ, 10 μM) and not suppressed by glibenclamide (10 μM), iberiotoxin (IbTX, 100 nM) and the combination of charybdotoxin (ChTX, 40 nM) plus apamin (100 nM).

Four‐aminopyridine (4‐AP, 1‐5 mM) generated spontaneous rhythmic activities only in coronary arteries with regenerated endothelium which were abolished by SNP. Nevertheless, 4‐AP did not suppress the repolarization induced by SNP.

In vascular segments with regenerated endothelium, contracted with prostaglandin F2α (PGF2α), relaxation to bradykinin (BK, 30 nM) was unaltered despite a reduced production of cGMP (−70%). Indomethacin (10 μM) plus Nω‐nitro‐L‐arginine (L‐NA, 30 μM) reduced relaxation (−12% and −35% for native and regenerated endothelium, respectively) but did not abolish it.

The hyperpolarizations induced by BK were not altered by the presence of indomethacin and L‐NA and were unchanged in segments with regenerated endothelium.

These data are consistent with a contribution of impairment in NO production to the depolarization of SMCs. Nevertheless, EDHF responses to BK are sufficient to maintain a normal relaxation after angioplasty.

British Journal of Pharmacology (2002) 136, 1153–1161. doi:10.1038/sj.bjp.0704828
An N‐terminal histidine regulates Zn2+ inhibition on the murine GABAA receptor β3 subunit
Authors: Dunne Emma L , Hosie Alastair M , Wooltorton Julian R A , Duguid Ian C , Harvey Kirsten , Moss Stephen J , Harvey Robert J , Smart Trevor G
Published: September 2002

Whole‐cell currents were recorded from Xenopus laevis oocytes and human embryonic kidney cells expressing GABAA receptor β3 subunit homomers to search for additional residues affecting Zn2+ inhibition. These residues would complement the previously identified histidine (H267), present just within the external portal of the ion channel, which modulates Zn2+ inhibition.

Zinc inhibited the pentobarbitone‐gated current on β3H267A homomers at pH 7.4, but this effect was abolished at pH 5.4. The Zn2+‐sensitive spontaneous β3 subunit‐mediated conductance was also insensitive to block by Zn2+ at pH 5.4.

Changing external pH enabled the titration of the Zn2+ sensitive binding site or signal transduction domain. The pKa was estimated at 6.8±0.03 implying the involvement of histidine residues.

External histidine residues in the β3 receptor subunit were substituted with alanine, in addition to the background mutation, H267A, to assess their sensitivity to Zn2+ inhibition. The Zn2+ IC50 was unaffected by either the H119A or H191A mutations.

The remaining histidine, H107, the only other candidate likely to participate in Zn2+ inhibition, was substituted with various residues. Most mutants were expressed at the cell surface but they disrupted functional expression of β3 homomers. However, H107G was functional and demonstrated a marked reduction in sensitivity to Zn2+.

GABAA receptor β3 subunits form functional ion channels that can be inhibited by Zn2+. Two histidine residues are largely responsible for this effect, H267 in the pore lining region and H107 residing in the extracellular N‐terminal domain.

British Journal of Pharmacology (2002) 137, 29–38. doi:10.1038/sj.bjp.0704835
Characterization of two novel forms of the rat sulphonylurea receptor SUR1A2 and SUR1BΔ31
Authors: Gros Laurent , Trapp Stefan , Dabrowski Michael , Ashcroft Frances M , Bataille Dominique , Blache Philippe
Published: September 2002

The ATP‐sensitive potassium channel (KATP) of pancreatic β‐cells is composed of the sulphonylurea‐binding protein, SUR1, and the inwardly rectifying K+ channel subunit, Kir6.2. We have characterized two novel isoforms of rat SUR1 in the RINm5F insulin‐secreting cell line.

SUR1A2 is an allelic variant with a single amino acid change in the first nucleotide‐binding domain. Coinjection of SUR1A2 plus Kir6.2 into Xenopus oocytes or expression of a SUR1A2–Kir6.2 tandem in HEK‐293 cells yielded large currents with characteristics similar to the wild‐type KATP channel.

SUR1BΔ31, detected in several human tissues, is a splice variant of the rat SUR1 gene that lacks exon 31 of the corresponding human SUR1 gene. SUR1BΔ31 lacks the TM16–TM17 transmembrane‐spanning helices leading to a protein with a different transmembrane topology. Coinjection of SUR1BΔ31 plus Kir6.2 into Xenopus oocytes or expression of the Kir6.2/SUR1BΔ31 tandem construct in HEK‐293 cells did not result in any current, and a surface expression assay indicated that this channel does not reach the plasma membrane.

SUR1A2 and SUR1A1 proteins expressed in HEK‐293 cells display similar binding affinities for [3H]‐glibenclamide, while SUR1BΔ31 shows a 500‐fold lower affinity.

These findings confirm that TM16–TM17 of SUR1 are important for high‐affinity glibenclamide binding and that their deletion impairs trafficking of the KATP channel to the surface membrane.

British Journal of Pharmacology (2002) 137, 98–106. doi:10.1038/sj.bjp.0704836
Infusion of peripheral blood stem cells collected at diagnosis, with maintenance of the treatment, resulted in Ph‐negative recovery in a chronic myeloid leukaemia patient in persisting aplasia on STI‐571 therapy
Authors: Lewalle Philippe , Meuleman Nathalie , Verhest Alain , Bron Dominique , Martiat Philippe
Published: September 2002

Summary.  In advanced chronic myeloid leukaemia patients, STI‐571 produces complete haematological response in most cases and cytogenetic response in up to 50%. However, these patients often suffer periods of pancytopenia, which can lead to life‐threatening complications, and is probably due to the small number of residual normal stem cells. We have re‐infused peripheral blood stem cells collected at diagnosis, in a patient, while maintaining STI‐571 treatment. The patient recovered from aplasia, with Philadelphia‐negative haematopoiesis. Discontinuing an effective treatment because of persistent aplasia is a major concern; this method circumvents this problem inpatients who have undergone a stem cell harvest at diagnosis.
Hypoplastic myelodysplastic syndromes can be distinguished from acquired aplastic anaemia by bone marrow stem cell expression of the tumour necrosis factor receptor
Authors: Kasahara Senji , Hara Takeshi , Itoh Hiroyasu , Ando Kazuki , Tsurumi Hisashi , Sawada Michio , Yamada Toshiki , Ohnishi Hiroo , Moriwaki Hisataka
Published: September 2002

Summary. It is often difficult to distinguish hypoplastic myelodysplastic syndrome (h‐MDS) from acquired aplastic anaemia (AA), because of the considerable clinical, cytological and histological similarities between these two disorders. The distinction between AA and h‐MDS is important because there is a higher risk of progression to acute leukaemia in patients with h‐MDS compared with AA. Recent studies suggest that tumour necrosis factor‐alpha (TNF‐α) plays an important role in the development of AA. In order to determine the potential importance of TNF‐α in the differential diagnosis of hypoplastic bone marrow (BM) disorders, we examined whether analysis ofTNF‐receptor expression could be used as a tool to differentiate AA from h‐MDS. Flow cytometric analysis revealed that BM stem cells (CD34+) from AA patients have markedly greater TNF receptor (R) 1 and TNFR2 expression than those from patients with MDS and h‐MDS. We suggest that the BM stem cells with a high expression of TNFR in patients with AA may be potently sensitive to TNF‐α stimulation of differentiation. Thus, we propose that quantification of TNFR expression in BM stem cellsmay be a useful method to distinguish AA from h‐MDS.
Diagnostic value of d‐dimer in patients with a moderate pretest probability of deep venous thrombosis
Authors: Aguilar Carlos , Martinez Angela , Martinez Angel , Del Rio Concepcion , Vazquez Mar , Rodriguez Francisco J.
Published: September 2002

Summary. The negative predictive value (NPV) of d‐dimer (DD) for the exclusion of venous thromboembolism is, overall, high and tends to increase as clinical pretest probability decreases. We have assessed the accuracy of a diagnostic protocol including clinical evaluation and DD in 134 outpatients presenting with a moderate pretest probability of proximal deep venous thrombosis (DVT). In these patients, a negative DD value safely excluded DVT (NPV 100%, 95% CI 85–100) In our experience, these results are equivalent to those found for low‐pretest probability patients and therefore the same diagnostic strategy can be used for both risk groups.
Teaching the theory behind guidelines: the Royal College of General Practitioners Guidelines Skills Course
Authors: Eccles  , Grimshaw  , Baker  , Feder  , Hurwitz  , Hutchinson  , Lawrence
Published: September 2002

In the face of a perceived lack of widespread understanding of the theoretical issues underlying the development, dissemination and implementation of clinical guidelines, the Royal College of General Practitioners Guidelines Group developed a 2‐day course aimed at teaching the theory in these areas. The course was targeted at potential opinion formers and ran on six occasions. Postal questionnaire assessment of the course revealed high levels of satisfaction with all aspects of the course and high levels of reported use of the knowledge gained. Further developments of the course are discussed.
Neutralization Susceptibility of B Subtype Variant B′′ Primary HIV‐1 Isolates
Authors: Bongertz  , Costa  , Guimarães  , Grinsztejn  , The Hec/fiocruz Aids Clinical Research Group  , João Filho  , Galvão‐Castro  , Morgado
Published: September 2002

Susceptibility to autologous and heterologous neutralization of primary human immunodeficiency virus (HIV)‐1 isolates belonging to subtype B, to the B′′‐variant of subtype B or to subtype F from infected individuals residing in Rio de Janeiro was assayed. A lower infectivity of the B′′‐ and F isolates when compared to the classical B‐subtype HIV‐1 isolates was observed. Comparisons of neutralization susceptibilities were carried out for 19 B‐subtype, 11 B′′‐variant and two F‐subtype HIV‐1 isolates with plasma from autologous and heterologous samples. Frequency of autologous neutralization was slightly lower for B‐subtype isolates in comparison to B′′‐variant isolates. Heterologous intra‐subtype neutralization was significantly lower for B‐subtype than for the B′′‐variant or the F‐subtype isolates. While B‐subtype isolates were neutralized by most anti‐F‐subtype plasma, F‐subtype isolates, although most susceptible to F‐subtype antibodies, were highly susceptible to neutralization by anti‐B‐subtype antibodies. Cross‐neutralization for B′′‐variant and B‐subtype isolates was not as extensive as observed for B‐ and F‐subtype isolates. However, the results presented indicate a quite extensive cross‐neutralization between Brazilian HIV‐1 isolates.
Placental Transfer of IgG and IgG Subclass Antibodies Anti‐Purified Escherichia coli LPS O16, O6 and O111
Authors: Nagao  , Martinez  , Vieira  , Takano  , Costa‐Carvalho  , Carneiro‐Sampaio
Published: September 2002

We evaluated 22 paired maternal and cord sera regarding the presence of IgG and IgG subclasses against purified Escherichia coli LPS O6, O16 and O111 employing ELISA for titre and avidity analysis, isoelectric focusing associated with affinity‐blotting for spectrotypic analysis, and the Western‐blotting technique for recognition of the various bands in lipopolysaccharide (LPS). Levels of anti‐LPS IgG antibodies in cord sera were equivalent to their respective maternal sera, showing a significant correlation (P < 0.0001). IgG1 antibody levels were higher in cord sera than in maternal sera (P < 0.005 for anti‐O111, P < 0.05 for anti‐O16 and P < 0.02 for anti‐O6). Cord IgG2 antibody levels were not different from the maternal levels (P > 0.1). The levels of IgG3 and IgG4 were undetectable. The avidity of anti‐O6 and anti‐O111 IgG in 10 cord sera showed an extremely significant correlation with maternal antibody avidity (P < 0.0001). Identical patterns of recognition were found in the paired samples analysed by Western blotting. Most of the serum samples recognized the O‐repetitive chains and also the region corresponding to core and lipid A. Although the antibody spectrotypes varied among individuals, paired cord and maternal serum samples showed identical patterns. Our findings suggest the occurrence of placental transfer of IgG antibodies against LPS O6, O16 and O111, mainly involving the IgG1 or IgG2 subclasses.
Natural history of asthma from childhood to adulthood
Authors: Kay A. B. , Gelfand E. W. , Smith L. J. , Tashkin D.
Published: September 2002

Asthma is a common and complex condition, with considerable heterogeneity both in phenotype and in the underlying pathophysiology. This paper aims to address some of the recent advances in the understanding of asthma, as well as indicating how these advances reveal potential new avenues for therapeutic intervention. Current drug treatments, although effective at alleviating inflammatory symptoms, do little to target the underlying causative factors. The onset of asthma is controlled by a combination of genetic and environmental factors, and a greater understanding of these has highlighted the importance of early‐life infections, allergen avoidance and fetal and postnatal nutrition. An imbalance in the expression of T‐cell phenotypes is thought to play an important role in the pathophysiology of asthma, and further elucidation of the underlying immune mechanisms has identified new ways of modulating the course of the disease. It is clear that there is also a need for new drug strategies that are aimed at the diverse factors that both trigger the disease and determine its course and severity, as well as the immune mechanisms contributing to its pathophysiology. Treatment plans that address this diversity are likely to provide a more effective means of asthma management and, combined with current knowledge of causative factors, might even act to modulate the course and severity of the disease.
Macrophage colony‐stimulating factor induces indirect angiogenesis in vivo
Authors: Phillips Gregg D. , Aukerman Sharon L. , Whitehead Russell A. , Knighton David R.
Published: September 2002

The cytokine macrophage colony‐stimulating factor was implanted in the rabbit cornea over a wide dose range (1 ng to 100 µg) to assay its angiogenic activity in vivo. Neovascularization occurred in a dose‐dependent manner, and maximum angiogenesis occurred only with 100 µg. Histologic analysis revealed that the corneas were free of inflammation at the lower doses, but had slight inflammation at 50 and 100 µg. Nonspecific esterase staining of frozen sections and transmission electron microscopy revealed that the inflammatory cells were predominantly macrophages, with very few neutrophils present. This association of capillary formation with inflammation suggests an indirect mechanism of angiogenesis. The lack of neutrophils within the inflammatory cell infiltrate demonstrates that indirect angiogenesis can proceed without the local presence of neutrophils. This distinguishes macrophage colony‐stimulating factor from other indirect‐acting angiogenesis factors that have been identified to date.
In vitro and in vivo analysis of the inability of fetal rabbit wounds to contract
Authors: Krummel Thomas M. , Ehrlich H. Paul , Nelson Jeffrey M. , Michna Barbara A. , Thomas Brian L. , Haynes Jeffrey H. , Cohen I. Kelman , Diegelmann Robert F.
Published: September 2002

Fetal rabbit wounds that are sutured show excellent repair without obvious scarring. In contrast, an unsutured wound in a rabbit fetus does not close, and it appears that the process of wound contraction does not occur. Experiments were carried out to illustrate the mechanisms responsible for the noncontraction of open fetal rabbit wounds. Results showed that the lack of wound contraction was not an artifact caused by rapid fetal growth. With regard to the ability of cultured fetal fibroblasts to show cytoplasmic muscle‐induced cell contraction, we found that, in cultured fetal fibroblasts, cell contraction was induced by adenosine triphosphate. Contractile abilities of fetal‐derived fibroblasts were equivalent to those of adult‐derived fibroblasts. The fetal fibroblasts also demonstrated the generation of superior contractile activity when examined in a fibroblast‐populated collagen lattice model. Finally, the ability of amniotic fluid to alter wound contraction was addressed by means of the fibroblast‐populated collagen lattice in vitro model. Increasing concentrations of amniotic fluid inhibited fetal fibroblast lattice contraction. Therefore, rabbit amniotic fluid contains an inhibitor that may be partially responsible for the noncontraction of fetal rabbit wounds in utero.
Transforming growth factor‐β enhances connective tissue repair in perforated rat mesentery but not peritoneal macrophage chemotaxis
Authors: Franzén Lennart E. , Schultz Gregory S.
Published: September 2002

The perforated rat mesentery model was used to study the effect of transforming growth factor‐β (TGF‐β) on connective tissue repair and influx of macrophages into the peritoneal cavity during such repair. Sprague‐Dawley rats were laparotomized, and mesenteric wounds were made with a scalpel. A daily intraperitoneal injection of 0.5 µg TGF‐β was given for either 2 or 4 days. After 1 to 10 days, the animals received an intravenous injection of tritium‐labeled thymidine before decapitation. Macrophages were collected by peritoneal washing, and the number of closed perforations was counted. Peritoneal cells were quantitated and a labeling index was determined by autoradiography. TGF‐β given for either 2 (p < 0.001) or 4 (p < 0.004) days accelerated closure of perforations on days 3 to 7 after injury. Laparotomy as such significantly increased leukocyte influx (p < 0.004), as well as macrophage‐labeling index (p < 0.02). However, TGF‐β did not significantly influence either leukocyte influx or macrophage‐labeling index. We concluded that TGF‐β significantly enhances connective tissue repair in this perforated rat mesentery model and that TGF‐β—induced stimulation of repair is not caused by an increased influx of macrophages into the peritoneal cavity.
Regulation of collagen synthesis and messenger RNA levels in normal and hypertrophic scar fibroblasts in vitro by interferon alfa‐2b
Authors: Tredget Edward E. , Shen You J. , Liu Grace , Forsyth Norine , Smith Camilla , Robertson Harrop A. , Scott Paul G. , Ghahary Aziz
Published: September 2002

Hypertrophic scars, which commonly occur after thermal and traumatic injury of the skin, are a fibroproliferative disorder of the dermal matrix wherein components of the inflammatory process, including the fibrotic growth factor, transforming growth factor‐β, appear to activate dormant fibroblasts leading to cellular proliferation and excessive matrix synthesis. To investigate the potential beneficial role and mechanism of interferon alfa‐2b in controlling excessive collagen production in hypertrophic scar, we measured dose response, time of onset, and duration of action in hypertrophic scar fibroblasts in vitro and compared them with those of site‐matched normal fibroblasts obtained from four patients after thermal injury. Interferon alfa‐2b reduced collagen protein synthesis and type I messenger RNA levels in both hypertrophic scar and normal fibroblasts after treatment, but these changes were apparent only after approximately 72 hours. Significant reductions in collagen synthesis occurred in four pairs of normal and hypertrophic scar fibroblasts (p < 0.05), accompanied by significant reductions in type I (p < 0.05) but not type III procollagen messenger RNA. Hypertrophic scar fibroblasts recovered completely from the effects of interferon alfa‐2b on procollagen type I messenger RNA within 48 hours of cessation of treatment in contrast to normal skin fibroblasts, in which the reduction in type I procollagen messenger RNA by interferon alfa‐2b persisted beyond 72 hours after treatment. These data suggest that interferon alfa‐2b reduces collagen synthesis in both normal and hypertrophic fibroblasts but the hypertrophic fibroblast may remain less sensitive to its effects.
Mechanical analysis of the effects of bacteria and aprotinin on skin wound healing in adult guinea pigs
Authors: Stadelmann Wayne , Greenwald Daniel , Stevens Lisa , Shumway Scott , Leoni Karen , Krizek Thomas
Published: September 2002

Inhibition of wound healing by bacteria may result in part from the conversion of plasminogen to plasmin. This conversion results in dissolution of the fibrin seal in a wound or between skin graft and bed. Aprotinin blocks conversion to plasmin, preserving the fibrin clot. The current study was undertaken to determine the effects of high concentrations of bacteria on wound healing and how these effects are mitigated by aprotinin. Dorsal full‐thickness skin incisions were made in 40 anesthetized guinea pigs and closed with nylon sutures. Animals were divided into four groups: (1) control wounds, (2) infected wounds, (3) wounds treated with aprotinin, and (4) infected wounds plus aprotinin (single dose). Animals were killed 3 and 4 weeks after the operation. Skin strips containing segments of the healing wounds were pulled apart by a tensiometer until rupture. Stress‐strain curves were generated, and wound strength and toughness were determined. All wounds, including those inoculated with bacteria, appeared healed. The 3‐week infected group healed with the least strength and toughness (p < 0.001). A single dose of aprotinin administered with the bacterial inoculum reversed this inhibition. In the 4‐week groups, the strongest and toughest wounds resulted from bacterial inoculation alone. Aprotinin alone augmented wound healing when compared with controls. These data suggest that wound healing in both clean and infected wounds is augmented when the plasminogen‐plasmin pathway is inhibited.
Dermal substitutes for full‐thickness wounds in a one‐stage grafting model
Authors: De Vries Henry J. C. , Mekkes Jan R. , Middelkoop Esther , Hinrichs Wouter L. J. , Wildevuur Charles R. H. , Westerhof Wiete
Published: September 2002

We tested different biodegradable matrix materials as dermal substitutes in a porcine wound model. Matrixes were covered with a split‐skin mesh graft and protected with a microporous, semipermeable membrane, which prevents blister formation, wound infection and provides ultimate healing conditions. Evaluation parameters were as follows: epithelization, dermal reconstitution, wound contraction, and cosmetic and functional aspect. A microfibrillar matrix of nondenatured collagen gave the best result, with immediate fibroblast ingrowth and epidermal outgrowth. Slight inflammatory reaction and minimal wound contraction were observed. Application of a split‐skin mesh graft, in combination with this collagen matrix, generated a thicker dermal layer than did a split‐skin mesh graft directly applied on a wound bed. However, the histologic dermal architecture was less optimal than one obtained with a full‐thickness punch graft method. Other matrixes caused inflammatory reactions, interfering with epithelization and dermal reconstitution. We conclude that a nondenatured collagen matrix, in combination with a split‐skin mesh graft, can provide a substitute dermis in a full‐thickness wound. This combination is preferable to a split‐skin mesh graft directly applied on the wound bed. With our microporous semipermeable membrane, the combined use of a dermal substitute and a split‐skin mesh graft can be applied in a single‐stage operation.
Effects of basic fibroblast growth factor on the healing of partial‐thickness donor sites
Authors: Greenhalgh David G. , Rieman Mary
Published: September 2002

A phase I/II clinical study was performed to evaluate the safety and potential efficacy of topical recombinant human basic fibroblast growth factor on the healing of partial‐thickness skin graft donor sites in burned children. Each child served as his or her own control. In a blinded and random fashion, one donor site was sprayed with basic fibroblast growth factor (5 µg/cm2) on days 0 to 4 after harvest, whereas the other site was treated with vehicle. Twelve patients were entered in the study but one patient died of sepsis that was unrelated to growth factor treatment. Of the remaining 11 patients, no adverse events related to basic fibroblast growth factor occurred. Serum basic fibroblast growth factor levels were never detected and antibody levels remained unchanged. No differences in the rate of epithelialization or days until complete closure were noted (basic fibroblast growth factor = 12.9 ± 3.9 days, placebo = 12.2 ± 5.5 days; mean ± standard error of the mean). No differences in pain, itching, wound fragility, erythema, scarring, or pigmentation were noted. All of the scars matured within 1 year with good to excellent results. Investigators, patients, or families could not distinguish between the two wounds. Although basic fibroblast growth factor proved safe, no enhancement of donor site healing was seen in this small study. Because the time for donor site healing limits subsequent autograft use in patients with sizeable burns, studies should focus on accelerating healing in patients with larger burns where donor site healing is delayed and reharvest is required.
Gene expression of tenascin is altered in normal scars and keloids
Authors: Sible Jill C. , Rettig Wolfgang J. , Eriksson Elof , Smith Steven P. , Oliver Noëlynn
Published: September 2002

Tenascin is an extracellular matrix molecule with structural similarity to fibronectin. An increase in extracellular matrix content of both tenascin and fibronectin is associated with early wound healing and with various skin fibroses. However, the relationship of tenascin and fibronectin expression during scar remodeling and the formation of pathologic scars such as keloids is unknown. Expression of tenascin in normal and abnormal human scars was examined and compared with that of fibronectin by immunohistochemistry and in situ hybridization. Tenascin and fibronectin protein and messenger RNA contents were elevated in normal, mature scars relative to quiescent skin, similar to the situation during earlier stages of healing. Tenascin and fibronectin expression was further enhanced in keloids relative to normal skin and scar, and, as has been shown for fibronectin, tenascin expression in uninjured skin adjacent to keloids was indistinguishable from that in quiescent skin from unaffected individuals. These data suggest that tenascin and fibronectin gene expression are coordinated during later stages of normal wound healing and that a defect involving common regulatory elements for these genes is associated with the formation of keloids.
Experimental approaches to chronic wounds
Authors: Falanga Vincent , Grinnel Frederick , Gilchrest Barbara , Maddox Yvonne T. , Moshell Alan
Published: September 2002

The pathogenesis of most chronic wounds is unknown. In this report, we summarize several areas of investigation which appear ready for further progress and which were discussed at a recent National Institutes of Health workshop on this subject. Of note were presentations of research on the role of fibrosis in wound healing, interaction of cytokines, hypoxia, extracellular matrix formation, keratinocyte migration, and involvement of proteases and neuropeptides in chronic wounds.
Capillary morphogenesis during healing of full‐thickness skin grafts: An ultrastructural study
Authors: Goretsky Michael J. , Breeden Matthew , Pisarski Gregory , Harriger M. Dana , Boyce Steven T. , Greenhalgh David G.
Published: September 2002

Biologic mechanisms by which skin grafts become revascularized after transplantation are poorly understood. To investigate graft revascularization, we examined the pattern of capillary growth in full‐thickness skin grafts at serial time points. Full‐thickness skin (2 × 2 cm) was excised to muscle fascia from the bilateral hind limbs of adult male Lewis rats. The graft/wound base boundary was identified by placement of a polypropylene mesh on the wound beneath the graft. Excised skin was replaced in its original orientation and secured with silk sutures tied over a gauze bolster dressing. After 3, 5, 7, and 10 days, animals were killed, and their aortas were cannulated and infused with an acrylic polymer to generate vascular casts. Grafts were excised, tissues were digested, and casts were examined with the use of scanning electron microscopy. Transmission electron microscopy was performed on tissues infused with the acrylic polymer that were not digested. At day 3, an immature lobular pattern was observed extending from the neovascular plexi on the graft side of the polypropylene mesh. At day 5, defined vessels with lobular ends occurred with high frequency. At day 7, the number of observed lobular structures was greatly reduced, and high frequencies of depressions in acrylic casts suggested protrusion of endothelial cell nuclei. By day 10, lobular structures were rare, well‐defined microvascular plexi were contiguous with larger vessels, and depressions from endothelial cell nuclei appeared more shallow and less frequent. These findings suggest that (1) an immature lobular pattern representing either capillary outgrowth or extracapillary leakage occurs at day 3; (2) these immature lobules decrease, and more discrete capillaries increase by day 5; (3) vascular integrity is reestablished by day 7; (4) vascular plexi has regained full continuity, and there are suggestions that endothelial cell proliferation has subsided by day 10.
Mechanisms of TGF‐β action in connective tissue repair of rat mesenteric wounds
Authors: Franzén Lennart E. , Ghassemifar Nayer , Nordman Johnny , Schultz Gregory , Skogman Roger
Published: September 2002

We have recently reported that transforming growth factor‐β stimulates genuine connective tissue repair in the perforated rat mesentery and that this stimulation is not caused by increased macrophage chemotaxis. To further characterize the effect of transforming growth factor‐β1 on the enhanced rate of wound closure, we performed a series of morphometric analyses with determination of mitotic index, fibroblast labeling index, cellular density, neovascularization, and scar tissue formation. Actin expression close to the wound margin was also evaluated morphologically. Fibroblast cell proliferation was not stimulated by transforming growth factor‐β1 in either wounded or unwounded tissue. Transforming growth factor‐β1 did, however, significantly increase the formation of healing tissue postoperative days 5 to 10 (p < 0.05) and angiogenesis was significantly stimulated by transforming growth factor‐β1 postoperative days 7 and 10 (p < 0.005). The mean cellular density was significantly increased in unperforated, transforming growth factor‐β1‐treated membranes from days 3 to 10, and increased expression of actin with time was observed close to the wound margin. Transforming growth factor‐β1 was thus shown to be a potent stimulator of angiogenesis and healing tissue formation in connective tissue repair, but this stimulation mainly occurred after closure of perforations. The increased cellular density in the absence of stimulated proliferation and increased actin expression in wound cells indicate that contraction may be an important mechanism of connective tissue repair in the perforated rat mesentery.
Exposure to amniotic fluid inhibits closure of open wounds in the fetal rabbit
Authors: Haynes Jeffrey H. , Mast Bruce A. , Krummel Thomas M. , Kelman Cohen I. , Diegelmann Robert F.
Published: September 2002

In many species, open cutaneous fetal wounds do not heal in utero. Such open wounds have been shown to close only after their exclusion from amniotic fluid, thus leading to the hypothesis that amniotic fluid inhibits open wound healing. Therefore the effect of amniotic fluid exposure on the healing of open fetal skin wounds was studied. Fetuses of New Zealand White rabbits received a full‐thickness circular 4 mm diameter skin punch biopsy wound. Wounds were left uncovered, covered with a latex patch, or covered with a latex patch with a central hole (doughnut). This third group provided for wound exposure to amniotic fluid while controlling for any wound splinting effect of the patch. Wounds were harvested after 5 days, the wound area was determined planimetrically, and wound edges were examined by means of light microscopy. Analysis of glycosaminoglycans in the wound extra‐cellular matrix was performed on a separate group of wounds treated similarly. Uncovered wounds enlarged by an average of 60%, whereas wounds covered with the doughnut patch enlarged by an average of 24%. In contrast, the wounds in the patch‐covered group decreased in size by an average of 84%. Histologically all groups contained proliferating fibroblasts and epithelial migration at the wound edge but also an absence of granulation tissue. The patch‐covered wounds, which had decreased wound area, were significantly enriched in hyaluronic acid. These results suggest that the healing of the patch‐covered wounds occurs without the formation of granulation tissue, presumably through a process of cellular migration and proliferation and that healing was inhibited by exposure to amniotic fluid. Hyaluronic acid has been shown to be permissive of cellular migration and to play a key role in tissue regeneration. Therefore, we speculate that direct exposure of open wounds to amniotic fluid during the late stages of fetal development in the rabbit prevents hyaluronic acid deposition, which in turn may alter wound closure.
Healing of full‐thickness wounds treated with lyophilized cultured keratinocyte cell lysate in genetically diabetic mice
Authors: Roseeuw Diane I. , De Coninck Arlette L. , Vanpée Els S. , Delaey Bernard M. , Verbeken Gilbert L. , Draye Jean‐Pierre M.
Published: September 2002

The effect of a lyophilized cell lysate prepared from cultured human keratinocytes on the healing of full‐thickness wounds was evaluated in an impaired healing model. Full‐thickness wounds (8 mm in diameter) were made on the dorsal areas of female genetically diabetic mice C57 BL/KsJ (db/db) and their normal (db/+) littermates. Wounds were covered with an occlusive polyurethane film dressing and were treated for 5 days either with the lyophilized cell lysate from cultured human keratinocytes prepared in phosphate‐buffered saline solution or with phosphate‐buffered saline solution. In normal (db/+) mice, all wounds were closed 16 days after wounding, and more than 90% of the wound closure was due to wound contraction. Wound contraction accounted for a similar extent of wound closure in both lyophilized cell lysate‐treated and phosphate‐buffered saline solution‐treated wounds. In contrast, in the diabetic (db/db) mice, after histologic examination of the wounds 32 days after wounding, four of ten lyophilized cell lysate‐treated wounds and four of seven phosphate‐buffered saline‐treated wounds were found to be closed. Moreover, applications of lyophilized cell lysate from cultured human keratinocytes to full‐thickness wounds in diabetic db/db mice significantly decreased the contribution of contraction to wound closure. Day 32 after wounding, contraction contribution to wound closure amounted to 57.7%± 4.7% and 80.4%± 3.2% (mean ± standard error of the mean, p < 0.005) of the initial wound areas, respectively, for lyophilized cell lysate‐treated and phosphate‐buffered saline solution‐treated wounds. At this time of wound healing, the thickness of the dermis was increased 1.7‐fold by the keratinocyte cell lysate treatment, but neither epithelial migration from the wound edges nor the thickness of the regenerated epithelium were significantly affected. In conclusion, in diabetic (db/db) mice the application of lyophilized cell lysate from cultured human keratinocytes influenced the healing of the dermis and wound contraction, but had no effect on reepithelialization.
Surgical glove powders differentially modulate macrophage and lymphocyte‐derived cytokines and eicosanoids production in vitro
Authors: Tang Xin‐Min , Chegini Nasser , Fay Margaret F. , Masterson Byron J.
Published: September 2002

The objective of the present study was to determine the effect of surgical glove powders Biosorb, Keoflo, and CaCO3 and Hydrocote (a powder‐free film; Biogel) on cytokine and eicosanoid production by lipopolysaccharide/phorbol 12‐myristate 13‐acetate activated and unactivated HL60, U937, and RPMI 1788 cells, human monocyte/macrophage, and B lymphocyte cell lines. The unactivated cell culture—conditioned media contained a low level of interleukin‐1α and ‐1β, granulocyte macrophage colony stimulating factor, and tumor necrosis factor‐α, which significantly increased after activation (p < 0.05). Exposure of unactivated cells to glove powders or Hydrocote (100 µg/ml) had little effect. However, these compounds appeared to have multiple inhibitory and stimulatory action on the production of these cytokines and eicosanoids in lipopolysaccharide/phorbol 12‐myristate 13‐acetate activated cells. For instance, granulocyte macrophage colony stimulating factor production was inhibited only in U937 cells by Keoflo and CaCO3, whereas, tumor necrosis factor‐α production was stimulated by Biosorb and Keoflo in HL‐60, and CaCO3 was found to be predominantly inhibitory on tumor necrosis factor‐α production by these cells (p < 0.05). Total transforming growth factor‐β1 production was stimulated by Biosorb and Hydrocote in U937 and HL‐60 cells, respectively, but inhibited by Keoflo in U937 cells. However, Biosorb and Keoflo inhibited transforming growth factor‐β1 production in both HL‐60 and RPMI 1788 cells, without any effect on active transforming growth factor‐β1. With regard to eicosanoids, Biosorb and Keoflo stimulated prostaglandin E2 production by RPMI 1788 cells, whereas it was inhibited by all glove powders in HL‐60 cells. Thromboxane B2 production was stimulated by Keoflo and inhibited by CaCO3 and Hydrocote in U937 cells. Finally, Leukotriene B4 synthesis was found to become stimulated by Keoflo, CaCO3, and Hydrocote in both HL60 and RPMI 1788 cells (p < 0.05). These data indicate that exposure of activated, but not unactivated, macrophages and lymphocyte to surgical glove powders and Hydrocote differentially effects the release of cytokines and eicosanoids by these cells. Considering that cytokines and eicosanoids play an important role in mediating the inflammatory and immune responses of wound healing, complications arising from glove powder exposure in vivo may involve mechanisms which alter the type and level of cytokine and eicosanoid production.
The wound healing process in surgical patients evaluated by the expanded polytetrafluoroethylene and the polyvinyl alcohol sponge: a comparison with special reference to intrapatient variability
Authors: Jorgensen Lars N. , Olsen Lars , Kallehave Finn , Karlsmark Tonny , Diegelmann Robert F. , Kelman Cohen I. , Gottrup Finn
Published: September 2002

The aim of this study was to compare two wound healing models in surgical patients with special reference to the intrapatient variability. Two pieces of expanded polytetrafluoroethylene tubing and one perforated silicone tube containing two polyvinyl alcohol sponges were subcutaneously inserted into 28 patients and were removed after 10 (9 to 11) days. The amount of hydroxy‐l‐proline in two segments of the same piece of expanded polytetrafluoroethylene tubing correlated significantly with each other. Similar results were found for proline. Proline content in each polyvinyl alcohol sponge correlated weakly with each other, whereas no correlation was found between hydroxy‐l‐proline content in the two polyvinyl alcohol sponges from the same patient. In addition, no correlation was found between leucine in the two adjacent polyvinyl alcohol sponges or between the hydroxy‐l‐proline/leucine ratio in these same sponges. No concordance could be detected between the averages of hydroxy‐l‐proline content in the two segments of expanded polytetrafluoroethylene tubing and the hydroxy‐l‐proline content in the two polyvinyl alcohol sponges from the same person, although an association between the averages of proline in the two pieces of expanded polytetrafluoroethylene tubing and proline content in the two polyvinyl alcohol sponges from the same individual was observed. The measurement error was greater for the polyvinyl alcohol sponges than for the expanded polytetrafluoroethylene tubing implants during the first 10 days after wounding. The expanded polytetrafluoroethylene tubing accumulated 2.5 times more hydroxy‐l‐proline per length unit than the polyvinyl alcohol sponge. We concluded that the expanded polytetrafluoroethylene implant rather than the polyvinyl alcohol implant is preferred for quantitation of subcutaneous collagen deposition in surgical patients because it accumulates more new tissue and has a lower variability.
Effect of growth factors on the characteristics of cells associated with equine wound healing and sarcoid formation
Authors: Cochrane C. A. , Freeman K. L. , Knottenbelt D. C.
Published: September 2002

Wound healing in equidae is delayed and more complicated than in other species. These complications arise from a condition known as exuberant granulation tissue formation. The lower limb of the horse is frequently slower to heal than other parts of the body and has a particular tendency to produce excess (exuberant) granulation tissue. Sarcoids are tumor‐like lesions of the skin which often appear at the site of wounds. This study compared the growth characteristics of the sarcoid and granulation tissue‐derived cells with normal dermal fibroblasts grown from primary cell cultures. All three cell types had distinct morphologic differences. Growth rate studies showed that the sarcoid and granulation tissue‐derived cells grew at a slower rate than the normal cells. The addition of the growth factors epidermal growth factor, acidic fibroblast growth factor, and basic fibroblast growth factor selectively stimulated the replication of normal and sarcoid‐derived cells but inhibited the growth of granulation tissue‐derived cells. In contrast, transforming growth factor‐β was not preferentially inhibitory for the granulation tissue‐derived cells. The addition of growth factors to the medium also produced distinct alterations in the morphology of the cells.
Biochemical analysis of wound fluid from nonhealing and healing chronic leg ulcers
Authors: Trengove Naomi J. , Langton Simon R. , Stacey Michael C.
Published: September 2002

The purpose of this study was to determine the biochemical composition of fluid taken from chronic wounds, to compare these values with that of serum, and therefore to assess whether the wound fluid is representative of the extracellular environment of the wound. Paired wound fluid and blood samples were collected from eight patients with chronic leg ulcers in a nonhealing and healing phase. Wound fluid and serum samples were screened for a profile of general biochemical analyses, including electrolytes, lactate, glucose, and protein analyses. Electrolyte levels were essentially identical in wound fluid and serum samples. Lactate and lactate dehydrogenase levels were significantly greater and glucose and bicarbonate levels were significantly lower in wound fluid when compared with the paired serum samples. Albumin and total protein levels in wound fluid were on average half those of serum levels. In this small sample of eight patients, wound fluid collected from chronic leg ulcers is an exudate with the biochemical composition expected in extracellular fluid. In addition, bicarbonate and glucose levels increase and C‐reactive protein levels decrease in wound fluid, but remain unchanged in serum, during healing. These results suggest changes in the state of hypoxia and the inflammatory process in the healing wound.
Histochemical analysis of growth factor, fibronectin, and iron content of sickle cell leg ulcers
Authors: Francillon Yvan J. , Jilly Pongrac N. , Varricchio Frederick , Castro Oswaldo
Published: September 2002

To better understand the pathogenesis and slow healing of sickle cell leg ulcers, we analyzed tissues for their content of iron and their immunohistochemical level of basic fibroblast growth factor, transforming growth factor‐β, and fibronectin. Debrided leg ulcer tissue from seven patients with sickle cell anemia were used. All sections stained strongly for basic fibroblast growth factor. The reactions to iron and fibronectin were variable (trace to 4+, 0 to 3+, respectively), and there was weak or negative immunohistochemical staining for transforming growth factor‐β. These findings suggest the possibility that iron and/or a low content of transforming growth factor‐β and fibronectin may play a role in the chronicity of these lesions. Conversely, reducing tissue iron and/or applying transforming growth factor‐β or fibronectin topically may promote the healing of sickle cell leg ulcers.