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PubMed1990

Injection of illicit drugs into the granulation tissue of chronic ulcers.

Chronic skin ulcers are rare among healthy young adults. Local injection of cocaine and heroin has been identified as a cause of chronic skin ulcers in young adults abusing intravenous drugs. These patients use both engorged veins surrounding the ulcers and the granulation tissue itself for the injection of drugs. We believe that chronic skin ulcers in young adults should be a marker for intravenous drug abuse, and should be considered in the differential diagnosis of nonhealing wounds.

Adult↗
PubMed1986

Nonenzymatic glycosylation of proteins and protease activities in granulation tissues in experimental diabetes.

Serum proteins and hemoglobins show increased nonenzymatic glycosylation in diabetes mellitus. The measure of glycosylated proteins, particularly hemoglobin, is considered to be a preferred indicator in the control of diabetes. In a study of diabetes and inflammation, we assessed the extent of nonenzymatic glycosylation of proteins of granulation tissue from diabetic rats. Five, seven, and ten days after carrageenan injection, the granuloma proteins were extracted. Nonenzymatic glycosylation was measured in soluble and insoluble granuloma proteins by thiobarbituric acid assay. Protease activities and free amino groups were assayed in soluble extracts. Nonenzymatic glycosylation in soluble proteins of both groups reached a maximum on the seventh day. However, nonenzymatic glycosylation in soluble proteins of the diabetic granulomas was significantly greater than the controls on days five and seven. During the days after granuloma induction, nonenzymatic glycosylation in the insoluble granuloma tissue proteins gradually decreased without any significant differences between controls and diabetics. Significant decreases in the free amino groups in soluble proteins of the diabetic tissues were noted. Greater activities of cathepsins B and D were noted in diabetic tissues over controls. These observations suggest that, in addition to increased proteolysis, increased nonenzymatic glycosylation of tissue proteins could be associated with the impaired process of wound healing in diabetics.

Animals↗
PubMed1984

In vivo co-distribution of fibronectin and actin fibers in granulation tissue: immunofluorescence and electron microscope studies of the fibronexus at the myofibroblast surface.

The fibronexus ( FNX ), a very close transmembrane association of individual extracellular fibronectin fibers and actin microfilaments, was found previously at the substrate-binding surface of fibroblasts in tissue culture (Singer, 1. 1., 1979, Cell, 16:675-685). To determine whether the fibronexus might be involved in fibroblast adhesion during wound healing in vivo, we looked for co-localization of actin and fibronectin in granulation tissue formed within full-thickness guinea pig skin wounds. At 7-9 d, most of the actin fibers were observed to be coincident with congruent fibronectin fibers using double-label immunofluorescence microscopy. These fibronectin and actin fibers were co-localized at the myofibroblast surface surrounding the nucleus, and along attenuated myofibroblast processes which extended deeply into the extracellular matrix. This conspicuous co-distribution of fibronectin and actin fibers prompted us to look for fibronexuses at the myofibroblast surface with electron microscopy. We observed three kinds of FNXs : (a) tandem associations between the termini of individual extracellular fibronectin fibers and actin microfilament bundles at the tips of elongate myofibroblast processes, (b) plaque-like and, (c) track-like FNXs , in which parallel fibronectin and actin fibers were connected by perpendicular transmembranous fibrils. Goniometric studies on the external and internal components of these cross-linking fibrils showed that their membrane-associated ends are probably co-axial. Using immunoelectron microscopy on ultrathin cryosections, we confirmed that the densely staining external portion of these various FNXs does indeed contain fibronectin. The finding that these FNXs appear to connect collagen fibers to intracellular bundles of actin microfilaments is particularly significant. Our studies strongly suggest that the fibronexus is an important in vivo cell surface adhesion site functioning in wound repair, and perhaps within fibronectin-rich tissues during embryogenesis, tumor growth, and inflammation.

Actins↗
PubMedDate not supplied

Differential regulation of collagen gene expression in granulation tissue and non-repair connective tissues in vitamin C-deficient guinea pigs.

Poor wound healing during vitamin C deficiency is thought to be due to decreased hydroxylation of proline residues in collagen. In non-repair connective tissues of guinea pigs, however, procollagen gene expression is not decreased until weight loss occurs during the third and fourth weeks of scurvy (phase II) with only a moderate decrease in proline hydroxylation. Decreased procollagen gene expression is related to the induction of insulin-like growth factor binding proteins 1 and 2 that inhibit insulin-like growth factor-I action. We examined wound healing and granulation tissue formation during phase I of vitamin C deficiency. Synthetic sponges were implanted on day 7 of vitamin C deficiency and analyzed at 6 and 10 days after surgery, when there was no weight loss or induction of insulin-like growth factor binding proteins. Healing of incisions was almost complete at 10 days after surgery in normal controls but not in scorbutic animals. The area around the incision and implant exhibited excessive angiogenesis and hemorrhaging of vessels in the scorbutic animals at 6 and 10 days after surgery. At 10 days after surgery, collagen synthesis in the implants of scorbutic guinea pigs was 36% lower than control values, with a normal extent of proline hydroxylation. Concentrations of messenger RNAs for types I and III procollagens were slightly increased by scurvy at 6 days after surgery but were decreased by 26% and 40%, respectively, at 10 days. Fibronectin mRNA levels were unaffected by scurvy at both time points. Our results suggest that poor wound healing in phase I of scurvy may be related to defective interstitial procollagen gene expression and defective blood vessel formation, but it does not involve inhibition of proline hydroxylation or induction of insulin-like growth factor binding proteins. mRNA for insulin-like growth factor-II, transforming growth factor-beta(1), and transforming growth factor-beta(2) were significantly expressed in implants, but their patterns of expression did not correlate with changes in procollagen gene expression.

Journal Article↗