Biomedical subjects

N S Gibran

Publications and source records attributed to N S Gibran.

34 records · Page 2Linked to original sources

PubMedDate not supplied

Role of alpha(v) integrins and angiogenesis during wound repair.

Angiogenesis, the formation of new blood vessels from pre-existing blood vessels, is thought to be critical for wound repair. Yet few studies have critically examined dermal wound repair in a system in which angiogenesis was impaired. Since alpha(v)-containing integrins are critical for angiogenesis, we administered either an alpha(v) integrin blocking antibody or cyclic Arg-Gly-Asp peptide into a murine excisional wound model to restrict wound angiogenesis. Although both methods markedly decreased wound angiogenesis, decreased angiogenesis had no significant effect on wound epithelization, contraction, or ultimate wound closure. These results suggest that if other cellular components of wound healing are intact, moderate impairment of angiogenesis alone does not necessarily retard normal wound healing.

Animals↗

PubMedDate not supplied

Cones of skin occur where hypertrophic scar occurs.

Hypertrophic scarring is devastating for the patient, however the pathophysiology and treatment remain unknown after decades of research. The process follows deep dermal injury, occurs only on certain body parts, does not occur in the early fetus or in animals, and is a localized event. This suggests that an anatomic structure in human, deep dermis may be involved. The dermis is a matrix perforated by cones containing many structures including skin appendages and fat domes. We hypothesized that studying the cones might reveal a structure related to scarring. We examined tangential wounds from various body parts on human cadavers along with skin histology from various human body parts, the early fetus, partial thickness burns, hypertrophic scars, and two other species-rats and rabbits. We found that the cones may in fact be the structure. They exist where hypertrophic scar occurs-cheek, neck, chest, abdomen, back, buttock, arm, forearm, dorsal hand, thigh, leg, dorsal foot, helix and ear lobe. They do not exist where hypertrophic scar does not occur-scalp, forehead, concha, eyelid, palm, early fetus, and in rat, or rabbit. It also became apparent that the cones have been omitted from most considerations of skin histology. We suggest that the cones need to be studied in relation to hypertrophic scarring and restored to skin diagrams.

Adult↗

PubMedDate not supplied

Substance P has a role in neurogenic mediation of human burn wound healing.

Knowledge of biochemical and molecular events during burn wound healing may optimize treatment of patients with thermal injuries. Substance P (SP), a neuropeptide present in C fibers of the skin, has been implicated as a mediator of inflammation and wound healing. This neuropeptide induces vasodilitation and vascular permeability by stimulating endothelial cells to round up, vascular smooth cells to relax, and mast cells to release histamine. SP also induces cytokine release by macrophages and neutrophils. Because many of the functions of SP seemed relevant to wound repair in burns, we used immunocytochemistry to characterize SP+ nerve fibers in healing human burn wounds. Deep partial-thickness burns collected from 20 patients at the time of excision and grafting were formalin fixed, paraffin-embedded, sectioned, and labeled with a monoclonal antibody to SP with use of an immunoperoxidase technique. Our tissue samples included normal skin and 20 specimens from postburn days 2 through 49. In normal adult skin, SP+ nerve fibers surrounded vessels throughout the skin and extended from the papillary dermis into the epidermis. SP+ fibers were absent in early wound beds. SP immunostaining did occur in the advancing epidermis, endothelial cells, and mast cells. SP+ fibers could be identified in the deep dermis and subjacent to the advancing epithelium before the wound beds. Maximum numbers of SP+ fibers were present subjacent to the advancing epithelium at 2 weeks after burn injury. After 4 weeks, the distribution of SP+ fibers in reepithelialized areas was similar to that of normal skin. Our data corroborate published reports of SP+ fiber regeneration in guinea pig burns and correlates with clinical observations of pain and pruritus in patients with thermal injuries. The absence of SP+ fibers in the early wounds with SP immunostaining in the epidermis and extracellular matrix suggests that SP may be released from injured nerves and supports neurogenic mediation of inflammation and vasodilitation in early wound repair. Repopulation of the wound beds with SP+ fibers appeared to follow neovascularization originating in the deep reticular dermis and wound edge.

Adult↗

PubMedDate not supplied

A burn wound healing model in the hairless descendant of the Mexican hairless dog.

Wound contraction and epithelialization occur much faster in animals than in humans. Therefore it is sometimes not valid to apply the results of animal wound healing studies to humans. Hairless descendants of Mexican hairless dogs (HD-MHD) have attracted attention because their skin characteristics approximate those of humans. We used this animal and compared the rate of healing of superficial dermal burns (SDB) and deep dermal burns (DDB) in the HD-MHD and normal beagles. We also compared the rate of healing with use of Vaseline (Chesebrough-Ponds) gauze (VG) and hydrocolloid dressings in the HD-MHD. The HD-MHD demonstrated less contraction (p < 0.05). Small pigmented spots could be seen in the HD-MHD wounds, suggesting that epithelialization started from epidermal appendages. SDBs treated with VG and hydrocolloid dressings were both epithelialized on day 18. DDBs treated with hydrocolloid dressings were epithelialized on day 24, whereas DDBs treated with VG were epithelialized on day 30. Like human wounds, burns in the HD-MHD epithelialize from appendages with less wound contraction. These similarities support the use of this burn wound healing model.

Animals↗

PubMedDate not supplied

Comparison of pain control medication in three age groups of elderly patients.

There are no published reports of burn pain management in the elderly population. To assess the range of requirement and use of opioids among elderly patients with burns of different age categories, a retrospective review of 89 consecutive admissions of patients over 55 years of age (January 1995 through July 1996) was conducted. Complete data were available on 44 patients with a burn mean total body surface area of 17.2%. Patient ages ranged from 55 to 92 years. Individuals were divided into three age categories: Group I (55 to 65) n = 20; Group II (66 to 75) n = 14; and Group III (76 to 92) n = 10. Use of commonly prescribed opioids for procedural pain and breakthrough pain were evaluated. We compared the opioid equivalents of medications prescribed versus the actual amount administered. Paired t tests comparing minimum amount of medication ordered with that given revealed Group I patients received significantly more procedural medication than the minimum prescribed (t = 3.88, p = 0.001), and that Group III patients were given significantly less as needed medication than the minimum prescribed (t = 2.58, p < 0.05).

Adult↗

PubMedDate not supplied

A biopsy of the use of the Baxter formula to resuscitate burns or do we do it like Charlie did it?

The Baxter formula is commonly used to calculate fluid requirements. Baxter reported that 12% of patients would require more than 4.3 mL/kg per percentage of total body surface area (%TBSA). We anecdotally observed that we frequently exceeded the predictions of the formula, and we wondered if this was unique to our practice. We studied our last 11 burn-related resuscitations and collected fluid resuscitation data from US burn centers. Twenty-eight centers were queried, and 6 centers shared data. We were therefore able to study the resuscitation data of 50 adult patients. For 29 patients (58%), 4.3 mL/kg/%TBSA was exceeded compared with the 12% reported by Baxter. These findings suggest that in actual practice, fluid volumes administered are larger than the Baxter formula predicts. This survey does not explain why. Possible reasons for the larger fluid volumes are as follows: (1) the sample is not representative; (2) the formula is used improperly; (3) burns have changed and require more fluids; (4) burn care has changed.

Adult↗

PubMedDate not supplied

Analysis of hypertrophic and normal scar gene expression with cDNA microarrays.

Hypertrophic scar is one form of abnormal wound healing. Previous studies have suggested that hypertrophic scar formation results from altered gene expression of extracellular matrix molecules. A broadscale evaluation of gene expression in hypertrophic scars has not been reported. To better understand abnormalities in hypertrophic scar gene expression, we compared messenger RNA expression in hypertrophic scars, normal scars, and uninjured skin with the use of complementary (c)DNA microarrays. Total RNA was extracted from freshly excised human hypertrophic scars, normal scars, or uninjured skin and reverse transcribed into cDNA with the incorporation of [33P] deoxycytidine triphosphate. The resulting radioactive cDNA probes were hybridized onto cDNA microarrays of 4000 genes. Hybridization signals were normalized and analyzed. In the comparison of tissue samples, mean intensities were calculated for each gene within each group (hypertrophic scars, normal scars, and uninjured skin). Ratios of the mean intensities of hypertrophic scars to normal scars, hypertrophic scars to uninjured skin, and normal scars to uninjured skin were generated. A ratio that was greater than 1 indicated upregulation of any particular gene and a ratio that was less than 1 indicated downregulation of any particular gene. Our data indicated that 142 genes were overexpressed and 50 genes were underexpressed in normal scars compared with uninjured skin, 107 genes were overexpressed and 71 were underexpressed in hypertrophic scars compared with uninjured skin, and 44 genes were overexpressed and 124 were underexpressed in hypertrophic scars compared with normal scars. Our analysis of collagen, growth factor, and metalloproteinase gene expression confirmed that our molecular data were consistent with published biochemical and clinical observations of normal scars and hypertrophic scars. cDNA microarray analysis provides a powerful tool for the investigation of differential gene expression in hypertrophic scar samples and either uninjured skin or normal scars. Our data validate the use of this technology for future studies on gene expression during repair processes of normal and abnormal wounds.

Adult↗

PubMedDate not supplied

Toxic epidermal necrolysis (TEN) in elderly patients.

Toxic epidermal necrolysis (TEN) is a severe exfoliative disease of the skin and mucous membranes that results in high mortality. As the elderly population increases, the number of elderly patients with TEN can also be expected to increase. Elderly patients with comparably sized burn wounds usually have a poor prognosis. Our purpose was to determine whether elderly TEN patients exhibit similarly high mortality. A retrospective review was conducted of 52 patients treated for TEN from October 1991 through September 1998. Eleven patients were older than 65 years. All patients were treated according to our TEN protocol. Eight of 11 patients recovered, and 3 died. The mean total body surface area (TBSA) involvement for the patients who recovered was 24%, compared with 66% for the nonsurvivors. The survival rate for elderly patients (73%) compares well with that for those younger than 65 years (89%). Therefore, we propose that we should be aggressive in treating elderly patients with TEN.

Aged↗

PubMedDate not supplied

Prospective trial of thick vs standard split-thickness skin grafts in burns of the hand.

For best function and appearance, thick skin grafts for hands are generally preferred to thinner grafts. But how thick is thick enough? This prospective randomized trial was designed to compare 0.015-inch skin grafts for burned hands to hand grafts that are 0.025 inches thick. Consecutive patients receiving skin grafts to hands were randomized to have sheet grafts using donor sites of 0.015-inch or 0.025-inch thickness. To prevent delayed healing and potential hypertrophic scarring, the thick graft donor sites were grafted with 0.008-inch grafts. There were no significant differences in range of motion, final appearance, or patient satisfaction between the two groups at 1 year. There were problems with donor site healing in both groups. We recommend that hand grafts for adults be at least 0.015 inches thick but do not see an advantage to the use of very thick (0.025-inch) grafts, even with thin split-thickness skin grafts to the donor site.

Adult↗

PubMedDate not supplied

Dexter: a tool to facilitate impairment ratings.

Calculating impairment in burn patients is crucial to understanding outcome. However, it is rarely reported after burns, presumably because the process of calculating impairment ratings is complicated and tedious. Computerized systems have been developed that facilitate the process, but it has not been established in burn patients that these systems reduce the time required to calculate impairment. We evaluated the Dexter Evaluation and Therapy System by Cedaron Medical Inc (Davis, CA). A sample of 10 manually recorded ratings was compared with 10 performed on the Dexter. Mean time for the manual technique was 65 +/- 35 minutes versus 37 +/- 13 minutes for the Dexter (P < .05, Mann-Whitney). The time taken to perform impairment ratings in burn survivors is significantly reduced by the use of the Dexter system. Time saving occurs primarily at three points: (1) electronic data entry directly from the measuring instruments, (2) compilation of data, and (3) rapid generation of reports.

Adult↗

PubMedDate not supplied

Time off work and return to work rates after burns: systematic review of the literature and a large two-center series.

The literature on time off work and return to work after burns is incomplete. This study addresses this and includes a systematic literature review and two-center series. The literature was searched from 1966 through October 2000. Two-center data were collected on 363 adults employed outside of the home at injury. Data on employment, general demographics, and burn demographics were collected. The literature search found only 10 manuscripts with objective data, with a mean time off work of 10 weeks and %TBSA as the most important predictor of time off work. The mean time off work for those who returned to work by 24 months was 17 weeks and correlated with %TBSA. The probability of returning to work was reduced by a psychiatric history and extremity burns and was inversely related to %TBSA. In the two-center study, 66% and 90% of survivors had returned to work at 6 and 24 months post-burn. However, in the University of Washington subset of the data, only 37% had returned to the same job with the same employer without accommodations at 24 months, indicating that job disruption is considerable. The impact of burns on work is significant.

Absenteeism↗

PubMedDate not supplied

Rates, trends, and severity of depression after burn injuries.

It is commonly assumed that patients hospitalized for burn treatment will experience some level of depression. However, little is known about the trends in severity of depression over time. The purpose of this study was to determine the rates and severity of depression over a 2-year period. The Beck Depression Inventory was administered at 1 month (N = 151), 1 year (N = 130), and 2 years (N = 125) after discharge. At 1 month, 54% of patients showed symptoms of moderate to severe depression, and at 2 years, 43% of the patients responding still reported moderate to severe depression. The average correlation between scores over time was high. Women had higher depression scores than men at each time period. An interaction between gender and having a head or neck injury was also observed at 1 month and 1 year after discharge. Results suggest that routine outpatient screening for depression is warranted.

Adolescent↗

PubMedDate not supplied

Dermatome setting for autografts to cover INTEGRA.

Using the INTEGRA Dermal Regeneration Template requires the outer silastic layer to be replaced with an autograft. We followed the manufacturer's directions for epidermal autografting and frequently obtained shredded, useless grafts, therefore, it seemed important to determine the proper dermatome setting. We evaluated dermatome settings from 0.002 to 0.012 inches. First, with feeler gauges, we verified the dermatome settings. Second, we harvested skin at various dermatome settings and measured the thickness histologically. We found that 1) the dermatome settings are reasonably accurate; 2) harvesting useful sheets at 0.002 and 0.004 inches is virtually impossible; 3) the variability of histologic graft thickness is enormous; and 4) a dermatome setting of 0.006 inches yields useful grafts. We no longer use the term epidermal autografting but rather ultrathin split-thickness grafting. To harvest these grafts, we now merely set the dermatome to 0.006 inches and make whatever midcourse corrections are necessary to obtain translucent grafts.

Adult↗

PubMedDate not supplied

Current management of purpura fulminans: a multicenter study.

Seven burn centers performed a 10-yr retrospective chart review of patients diagnosed with purpura fulminans. Patient demographics, etiology, presentation, medical and surgical treatment, and outcome were reviewed. A total of 70 patients were identified. Mean patient age was 13 yr. Neisseria meningitidis was the most common etiologic agent in infants and adolescents whereas Streptococcus commonly afflicted the adult population. Acute management consisted of antibiotic administration, volume resuscitation, ventilatory and inotropic support, with occasional use of corticosteroids (38%) and protein C replacement (9%). Full-thickness skin and soft-tissue necrosis was extensive, requiring skin grafting and amputations in 90% of the patients. One fourth of the patients required amputations of all extremities. Fasciotomies when performed early appeared to limit the level of amputation in 6 of 14 patients. Therefore, fasciotomies during the initial management of these patients may reduce the depth of soft-tissue involvement and the extent of amputations.

Adolescent↗

PubMedDate not supplied

The methamphetamine burn patient.

Early aggressive fluid resuscitation has significantly decreased the morbidity and mortality associated with volume losses from large burns. Although most patients are adequately resuscitated using the Parkland formula, we noted increased fluid requirements for shock resuscitation in patients involved in methamphetamine laboratory explosions. Because predominant users are young healthy individuals in their 20s and 30s, we had not anticipated burn shock resuscitation failures in this patient group. We reviewed our experience with burn patients with documented methamphetamine use to determine whether this patient group presents new dilemmas to the burn surgeon. A 2-year retrospective study of 30 patients (15 methamphetamine users, 15 controls) revealed that the methamphetamine burn patient requires two to three times the standard Parkland formula resuscitation. In this study, methamphetamine burns larger than 40% TBSA had a 100% mortality.

Adult↗

PubMedDate not supplied

The Unna 'sleeve': an effective postoperative dressing for pediatric arm burns.

The goal of this study was to develop a postoperative plan for sheet grafts that would protect the graft, yet would also eliminate the need for daily wound care. Eleven pediatric patients (13 arms burns) who underwent excision and grafting were included in our study. The total area on the arm ranged from 1% to 5% total body surface area. All grafts were sheet grafts held in place with steri-strips or sutures. The grafts were covered with a layer of greasy gauze, followed by an Unna done paste dressing, and then an elastic bandage. The Unna "sleeve" remained in place for an average of 6 days (range, 3 to 10 days). In eight cases, a second Unna sleeve was applied and removed 6 to 7 days later. In all 13 cases, additional wound care for grafts was unnecessary, and patients did not require extended inpatient hospitalization. Graft take was 100% in all cases, and no reconstruction was required.

Arm Injuries↗