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Biomedical subjects

S Herrick

Publications and source records attributed to S Herrick.

13 recordsLinked to original sources
PubMed1999

Role of elevated plasma transforming growth factor-beta1 levels in wound healing.

Transforming growth factor (TGF)-beta1 plays a central role in wound healing. Wounds treated with neutralizing antibody to TGF-beta1 have a lower inflammatory response, reduced early extracellular matrix deposition, and reduced later cutaneous scarring, indicating the importance of local tissue TGF-beta1. By contrast, increasing the local, tissue levels of TGF-beta1 increases the early extracellular matrix deposition but does not alter scar formation. Increased levels of plasma TGF-beta1 correlate with increased fibrogenesis in the lung, kidneys, and liver. The aim of the present study was to investigate the role of elevated systemic levels of TGF-beta1 on wound healing. We used transgenic mice that express high levels of active TGF-beta1 and have elevated plasma levels of TGF-beta1 and wild-type mice of the same strain as controls. Incisional wounds and subcutaneously implanted polyvinyl alcohol (PVA) sponges were analyzed. Surprisingly, cutaneous wounds in transgenic, TGF-beta1-overexpressing mice healed with reduced scarring accompanied by an increase in the immunostaining for TGF-beta3 and TGF-beta-receptor RII and a decrease in immunostaining for TGF-beta1 compared with wounds in control mice. By contrast, the PVA sponges showed the opposite response, with PVA sponges from transgenic mice demonstrating an enhanced rate of cellular influx and matrix deposition into the sponges accompanied by an increase in the immunostaining for all three TGF-beta isoforms and their receptors compared with PVA sponges from control mice. Together, the data demonstrate that increased circulating levels of TGF-beta1 do not always result in increased expression or activity in selected target tissues such as the skin. The two wound models, subcutaneously implanted PVA sponges and cutaneous incisional wounds, differ significantly in terms of host response patterns. Finally, the data reinforce our previous observations that the relative ratios of the three TGF-beta isoforms is critical for control of scarring.

Animals↗
PubMed1999

Fibrinogen.

Fibrinogen is a blood-borne glycoprotein comprised of three pairs of nonidentical polypeptide chains. Following vascular injury, fibrinogen is cleaved by thrombin to form fibrin which is the most abundant component of blood clots. As well as controlling blood loss at sites of tissue damage, other properties of fibrinogen have recently been discovered. For example, various cleavage products of fibrinogen and fibrin, released during coagulation and fibrinolysis, respectively, regulate cell adhesion and spreading, display vasoconstrictor and chemotactic activities, and are mitogens for several cell types including fibroblasts, endothelial and smooth muscle cells. Current research aims to define the bioactive fibrinogen molecule moieties and cellular receptors involved in these processes. Future studies may provide us with new opportunities to develop agents which are useful in promoting tissue repair or conversely in inhibiting fibrosis in inflammatory and fibroproliferative diseases where endothelial cell damage or chronic leakage of blood proteins is a feature.

Cardiovascular Agents↗
PubMed1997

Up-regulation of elastase in acute wounds of healthy aged humans and chronic venous leg ulcers are associated with matrix degradation.

Chronic wound healing states are often associated with aging, and despite the increased number of aged patients with nonhealing wounds, controversy still exists concerning the effects of age on wound repair. Our previous work showed that in both venous ulcers in humans and acute wounds in aged animals, fibronectin, an early component in granulation tissue, is deficient compared to normal skin and acute wounds in healthy young animals, respectively. In the present study, we have determined the protease responsible for fibronectin degradation by analyzing tissue taken from the margins of chronic venous ulcers and standardized acute cutaneous wounds collected from a large cohort of "Health status"-defined aged human subjects (screened as per the SENIEUR protocol). When tissue samples were subjected to fibronectin zymography, the main protease involved in the breakdown of fibronectin in both venous ulcers and acute wounds of elderly subjects was found to be a serine protease with a molecular weight of approximately 30 kd. This protease was identified as neutrophil elastase by immunoblotting. In tissue biopsies, elastase was localized to granulocytes by immunocytochemical techniques and shown to be present in greater quantities in venous ulcers and Day-7 and -14 healing acute wounds of healthy aged subjects relative to those of young subjects. The highest quantities were found in acute wounds of elderly women. Our results suggest that the process of aging in healthy human subjects is associated with an up-regulation of elastase during acute wound healing and that an abnormality in down-regulation of this protease could be partially responsible for the transition to chronic wound healing states in the aged.

Acute Disease↗
PubMed1991

Negotiating reality after physical loss: hope, depression, and disability.

The utility of different reality negotiation strategies among 57 persons who had traumatically acquired severe physical disabilities was examined. It was predicted that a sense of goal-directed determination ("agency"; Snyder, 1989) would predict lower depression and psychosocial impairment scores soon after injury. To meet the demands of rehabilitation and social integration, however, it was hypothesized that a sense of ability to find ways to meet goals ("pathways") would predict lower depression and psychosocial impairment among persons who had been disabled for a longer period. The expected interaction was significant in the prediction of psychosocial impairment but not of depression. The sense of pathways was predictive of impairment and depression regardless of the time since injury. Results suggest that in the reality negotiation process the different components of hope as defined by Snyder have salient effects on perceptions of ability to function in social capacities.

Activities of Daily Living↗
PubMedDate not supplied

Designing an infection control program.

Designing and implementing an infection control program for home care poses many challenges. Some of these challenges stem from a long-standing lack of research and on-site expertise in the home care setting. Recent changes in health care and the proliferation of external regulations regarding home care practice further complicate the development of an effective and efficient infection control program.

Home Care Services↗