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Biomedical subjects

R B Fratianne

Publications and source records attributed to R B Fratianne.

At least 19 recordsLinked to original sources
PubMed1992

Fibronectin binding and neutrophil aggregation in burn injury.

Fibronectin (Fn) plays an important role in the adhesive function of many cells including neutrophils (PMN). We examined the hypothesis that activated PMN develop binding sites for fibronectin which allows for the aggregation of contiguous PMN. Because PMN adhesive function is altered in acute burn injury, we also investigated the role of Fn in the aggregation of PMN from subjects with acute thermal injury. The chemotactic peptide, n-formylmethionyl leucyl phenylalanine, induced rapid binding of radioiodinated plasma Fn to PMN. Significant binding of Fn was detected as early as 30 sec poststimulus and maximal binding occurred at 5 min. Fn binding was only partially reversible and nonsaturable. The chemotactic peptide induced aggregation and binding of Fn to PMN with similar kinetics, concentration dependence, temperature, and cation requirements. In burn patients, PMN demonstrated a significant decrease in chemotactic peptide-induced aggregation which was associated with decreased binding of Fn. Alterations in the binding of Fn to PMN may be responsible, in part, for diminished aggregation responses of PMN in the early stages of thermal injury.

Burns↗
PubMed1991

Human keratinocytes cultured on collagen gels form an epidermis which synthesizes bullous pemphigoid antigens and alpha 2 beta 1 integrins and secretes laminin, type IV collagen, and heparan sulfate proteoglycan at the basal cell surface.

Single cell suspensions of human keratinocytes when seeded onto floating three-dimensional gels constructed with type I collagen form a tissue resembling epidermis. These morphogenetic events occur in a serum-free environment in the absence of fibroblasts. Light and transmission electron microscopy show that cells form a basal layer plus suprabasilar cell layers corresponding to the stratum spinosum, stratum granulosum, and stratum corneum. The suprabasilar keratinocyte layers show morphologies which resemble intact skin in which cells are connected by desmosomes and contain intermediate filaments and keratohyalin-fillagrin granules. The basal cell layer differs from skin in vivo in that there is no connection to a basement membrane via hemidesmosomes. Cells in the basal layers are polarized as evidenced by the secretion of type IV collagen, heparan sulfate proteoglycans, and laminin at the cell membrane interface with the collagen gel. These proteins are not organized into a cytological basement membrane. Bullous pemphigoid antigen, a protein component of hemidesmosomes, is synthesized by basal keratinocytes, but like the basement membrane proteins it is not incorporated into a definable cytological structure. Keratinocytes in the basal and suprabasilar layers also synthesize alpha 2 beta 1 integrins. The mechanisms of keratinocyte adhesion to the gel may be through the interactions of this cell surface receptor with laminin and type IV collagen synthesized by the cell and/or direct interactions between the receptor and type I collagen within the gel. This in vitro experimental system is a useful model for defining the molecular events which control the formation and turnover of basement membranes and the mechanisms by which keratinocytes adhere to type I collagen when sheets of keratinocytes are used clinically for wound coverage.

Adolescent↗
PubMed1990

Outpatient management of partial-thickness burns: Biobrane versus 1% silver sulfadiazine.

A randomized, prospective study comparing the use of Biobrane (group 1) with the use of 1% silver sulfadiazine (group 2) in treating 56 partial-thickness burn wounds was carried out in 52 outpatients with burns that comprised less than 10% of their total body surface area. The two groups were similar in age, gender, race, and extent of burn. Wounds of patients in group 1 (30) were compared with those of group 2 (26) for healing time, pain, compliance with scheduled visits, and costs. Infected and skin-grafted wounds were excluded from healing time analysis. Infection rates of the two groups were similar (three of 30 vs two of 26). One patient in each group underwent skin grafting. Healing times of group 1 wounds were significantly less than those of group 2 (10.6 +/- 0.8 vs 15.0 +/- 1.2 days, P less than .01). Using a pain scale of 1 to 5, Biobrane-treated patients averaged lower pain scores at 24 hours after the burn (1.6 +/- 0.8 vs 3.6 +/- 1.3 P less than .001) and used less pain medication. Compliance with scheduled outpatient visits was also improved in the Biobrane-treated group (88.6% vs 63.2% attendance, P less than .001). Idealized total treatment costs averaged $434 for patients in group 1 compared with $504 for patients in group 2. We conclude that when used on properly selected wounds, Biobrane therapy can significantly decrease pain and total healing time without increasing the cost of outpatient burn care. Improved patient compliance may be an added benefit.

Adolescent↗
PubMed1989

The interaction of human papillary and reticular fibroblasts and human keratinocytes in the contraction of three-dimensional floating collagen lattices.

Fibroblasts derived from the papillary and reticular dermis of human skin and human keratinocytes show differences in their abilities to contract floating three-dimensional gels constructed from type I collagen. Reticular fibroblasts produce greater gel contraction than papillary fibroblasts. When equal numbers of papillary and reticular fibroblasts are mixed in the gels, papillary fibroblasts consistently inhibit gel contraction by reticular fibroblasts indicating interaction between these cell types in the contraction process. Surprisingly, keratinocytes alone produce greater gel contraction than that produced by either fibroblast type. Cooperativity in the gel contraction process is observed when fibroblasts are incorporated into the collagen matrix and keratinocytes are seeded onto the gel surface. Keratinocytes and dermal fibroblasts adhere to the collagen fibril to induce gel contraction by different mechanisms. Fibroblast contraction of collagen gels does not require fibronectin but is a serum-dependent reaction. In contrast, keratinocyte contraction of collagen gels occurs in a serum-free environment. Polyclonal, affinity-purified antibodies to human plasma fibronectin at high concentrations do not inhibit gel contraction by keratinocytes, making unlikely the possibility that fibronectin synthesized by the keratinocyte is a significant factor in the gel contraction process. We are currently examining the possibilities either that keratinocytes are synthesizing other adhesion proteins or that receptors on the cell surface can interact directly with the collagen fiber.

Cell Adhesion↗
PubMed1989

Risk factors associated with intravascular catheter infections in burned patients: a prospective, randomized study.

A prospective, controlled study of 101 intravascular catheter sites was undertaken to determine the importance of tubing manipulation and skin contamination in the etiology of catheter infection in burned patients. Catheters in place for 3 days were randomized to have the tubing changed every 24 or 48 hours. Catheters were removed at 72 hours and the tips cultured by the semi-quantitative technique of Maki. Hubs were cultured (by swab culture) at times of tubing change and at the time of catheter removal. Skin cultures of the area surrounding the catheter were done at the time of insertion and removal. Catheter tip infection was defined as 15 or more colony forming units. Positive cultures were found in 25.7% of the cases, and were most often due to Pseudomonas species (33%) and coagulase-negative Staphylococcus (29%). Infections occurred in 35% of arterial catheters, 27% of central, and 12% of peripheral venous catheters. No benefit was observed from changing the administration tubing at 24 hours vs. 48 hours. Hub cultures were positive 30% of the time at 24 hours, 39% at 48 hours and 41% at 72 hours. Although the isolated organisms correlated with tip cultures, false positive rates varied from 8 to 62%. Discriminant analysis showed no relationship between catheter infection and burn size or day postburn; however, the incidence of catheter infection correlated inversely with the distance of the catheter insertion site from the burn wound (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Neutrophil adhesive dysfunction in thermal injury: the role of fibronectin.

We examined neutrophil substrate adherence in 19 subjects with burns involving 1%-83% of their body surface area. Within 24 h of injury, neutrophils from burn patients demonstrated a 50% reduction in adhesion to both gelatin and plastic substrates when stimulated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), phorbol myristate acetate, and calcium ionophore A23187. Neutrophil substrate adherence examined as long as two weeks after burn injury remained abnormal. Neutrophils, from burn patients, stimulated with FMLP, phorbol myristate acetate, and calcium ionophore A23187 demonstrated a 51%, 37%, and 45% decrease, respectively, in release of immunoreactive fibronectin compared with control neutrophils. In neutrophils from burn patients there was a 31% reduction in total neutrophil-associated fibronectin compared with controls. The decrement in release and total cellular content of fibronectin in neutrophils from burn patients did not change when reexamined on day 7 after injury. The magnitude and time course of alterations in the cellular content and release of fibronectin correlate with adhesive dysfunction after burn injury.

Adult↗
PubMed1988

Biosynthetic skin substitute vs. 1% silver sulfadiazine for treatment of inpatient partial-thickness thermal burns.

When used appropriately on superficial or moderate-depth partial-thickness burns, Biobrane significantly decreased total healing time to complete reepithelialization, reduced pain, and was associated with decreased nursing time and costs when compared to 1% silver sulfadiazine cream. Care must be used in selecting wounds for Biobrane therapy. They must be fresh, noninfected, and free of eschar and debris with a moist, sensate surface that demonstrates capillary blanching and refill. Wounds must be inspected regularly for nonadherence and signs of infection. Early fluid accumulation requires prompt aspiration. Biobrane should be removed if fluid reaccumulates or the Biobrane becomes nonadherent at any time after 48 hours. When used appropriately, Biobrane offers significant advantages over conventional therapy of acute partial-thickness burns.

Adolescent↗
PubMed1987

Coverage of the open sternotomy wound with Biobrane dressing.

Massive edema accumulated after prolonged cardiopulmonary bypass for coronary grafting such that neither the sternum nor the presternal skin could be closed after insertion of a left ventricular assist device. To protect the mediastinum from infection, we applied Biobrane synthetic temporary wound dressing and placed a moist gauze dressing over it. When the dressing was removed 4 days later, the wound was pink, granulating, free from infection, and suitable for closure. Use of Biobrane biologic dressing should be considered when the mediastinum must remain exposed after median sternotomy.

Bandages↗
PubMed1986

Northeastern Ohio Trauma Study: V. Burn injury.

Burn injury cases were identified from a population-based sample of trauma visits to hospital emergency departments in northeastern Ohio during 1977. The 199 cases represented 2.4% of all trauma incidence visits by residents of the five-county study region. Ninety-five per cent of the burn cases were released from the emergency department directly after treatment. The annual incidence rate of emergency department-treated burns was 4.7 per 1,000 population. Incidence rates for males were twice those for females. The age groups with the highest annual incidence rates were those under 5 years of age and 25-34 years (seven and eight cases per 1,000 population, respectively). Most burns occurred at home or the workplace. The youngest employed age group sustained the highest rate of work-related burns. Hot or corrosive substances caused two thirds of all burns; fire and flames caused one fourth.

Accidents, Home↗
PubMed1986

Verapamil potentiates vagally mediated sinoatrial chronotropic responses in dogs.

A brief burst of electrical stimuli delivered to the vagus nerve during the cardiac cycle elicits a triphasic cardiac chronotropic response. The cardiac cycle length initially increases, then briefly decreases, and subsequently increases again. We studied the effects of a calcium channel blocking agent, verapamil, on these responses to vagal stimulation during sinoatrial nodal rhythm in anesthetized, open-chest dogs. Verapamil increased the basal cardiac cycle length only slightly; however, the primary cardioinhibition was accentuated approximately 40% (from 396 to 555 ms) by verapamil. Neither the acceleratory phase of this triphasic response nor the secondary cardioinhibition was significantly affected by verapamil. These results indicate that verapamil potentiates the initial action of acetylcholine at the sinoatrial node when the vagus is activated with brief stimuli.

Acetylcholine↗
PubMed1979

Delayed definitive reconstruction of the burned hand: evolution of a program of care.

Experience gained in treating patients with hand burns admitted to an active Regional Burn Center has resulted in the development of a biphasic approach which separates early healing and later reconstructive surgical procedures. This schedule permits late definitive surgery on healed functioning hands and is accomplished in a single operation in most cases. This biphasic approach has led to better results at our institution in terms of hand function and appearance, and to a decrease in total numbers of surgical procedures. Reports of others using alternative methods and schedules, also with satisfactory results, are discussed.

Burns↗
PubMed1976

Platelet aggregation as a sign of septicemia in thermal injury. A prospective study.

Serial measurements of coagulation activity, platelet counts, and platelet aggregation were done in patients with full-thickness burns involving 25% or more of body surface area to detect specific changes that might correlate with the onset of septicemia. Mean and maximal values for prothrombin time, partial thromboplastin time, thrombin time, activities of factor V and factor VIII, and concentrations of fibrinogen and fibrinogen-related antigens observed in the presence of bacterial septicemia did not differ significantly from those observed in the absence of septicemia. Mean platelet counts were significantly less with sepsis, but values in individual subjects were not indicative of the presence of septicemia. By contrast, platelet aggregation in response to adenosine diphosphate, epinephrine, and collagen always became severely abnormal with the onset of septicemia but not in the absence of sepsis.

Anti-Bacterial Agents↗