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Biomedical subjects

L G Phillips

Publications and source records attributed to L G Phillips.

At least 55 records · Page 3Linked to original sources

Clinical studies on growth factors in pressure sores: preliminary report.

Agents touted to benefit chronic non-healing wounds will become evermore prevalent. Examples, in addition to those cited, might include epictor (EGF) or platelet derived growth factor (PDGF). Although they may look promising in in vitro and experimental animal studies, they must be tested in humans. The pressure sore is a chronic three dimensional wound which lends itself to study of wound healing agents. It has been used for severe such trials and appears to be an excellent model for the continued study of peptide growth factors.

Disaccharides↗

The effect of venous obstruction in infected pedicle flap.

A new model of soft-tissue infection is used to investigate the effect of the local wound environment on the septic focus. Island pedicle flaps were raised on the buttock of 24 adult ewes and multiply inoculated with Staphylococcus aureus. Flaps with bacterial inoculation, without compromise of venous outflow, showed distal necrosis (mean +/- SEM percent of surface area, 25.8% +/- 8.6%) and developed septic foci with bacterial counts one log less than the amount injected. Flaps with inoculation and venous outflow obstruction underwent subtotal necrosis (mean percent of surface area, 73.3% +/- 11.2%) and had counts two logs higher than the nonobstructed flaps but without discrete septic foci. Flaps without inoculation, with or without venous obstruction, survived completely. Venous outflow obstruction is shown herein to potentiate tissue necrosis by raising bacterial counts in a septic focus and preventing defensive abscess formation by the host.

Animals↗

The scalp as a donor site: revisited.

The scalp cannot be used as skin graft donor site with impunity. A review of 2,620 charts identified 194 pediatric patients whose scalps served as donor sites for split-thickness skin grafts for the treatment of acute burns. The overall incidence of alopecia was 32%. However, the incidence of alopecia in unburned scalps was 13%. The occurrence of alopecia in this group was associated with larger burn area requiring more frequent use of the scalp and shorter intervals between graft harvests (p less than 0.05). Among this group of patients (n = 15), nine had mild spotty alopecia, four had surgically correctable alopecia, and two had global patchy alopecia not amenable to surgical correction. In the patients with concomitant burns to their scalps, the incidence of alopecia was 61%. Whether the burn or the graft harvest caused alopecia could not be established. Meticulous donor site care is mandatory in this latter group when the scalp donor site is indicated.

Adolescent↗

Uses and abuses of a biosynthetic dressing for partial skin thickness burns.

The following report reviews 851 applications of Biobrane on partial skin thickness burn wounds awaiting epithelialization. After the patients had been evaluated and resuscitated as needed, the burn wounds were cleansed and debrided. Those evaluated as shallow were treated with Biobrane application. Joint surfaces were splinted for immobilization. The wound was inspected at 24 and 48 h and if any fluid had accumulated it was aspirated and the wound was redressed. When the Biobrane was adherent, the wound was covered with a light dressing and joint immobilization was discontinued. Treatment with Biobrane dressing provided certain advantages over other topical wound care. As the dressing changes were performed less frequently outpatient care was possible, with a resultant decrease in both the length of hospital stay and the ultimate cost of burn care. Wound desiccation is prevented and pain is decreased. Accurate diagnosis of wound depth is crucial if Biobrane is to be used. Very deep wounds will not allow Biobrane adherence, neither will it occur if the wound has a high bacterial count. If joint surfaces are not splinted, the Biobrane will shear and not adhere to the wound. Convex and concave surfaces can be treated with Biobrane, which may need to be meshed.

Adolescent↗

Treating minor burns. Ice, grease, or what?

Minor burns are common but require early and appropriate care to avoid infection and scarring. Damage can be arrested by immersing the burn in cold water as soon as possible. The goals of care are then to remove dead tissue and protect viable tissue during healing. Very superficial burns require only application of an emollient to limit inflammation and pain and prevent desiccation. Partial-thickness burns that are clean and superficial may benefit from use of a biosynthetic bilaminar membrane dressing, which forms a skin substitute while protecting the wound. A patient with an infected wound or one on a primary area (hands, feet, face, or perineum) may have to be hospitalized to ensure proper care.

Bandages↗

The effect of endogenous skin bacteria on burn wound infection.

Burn wound sepsis can be due to exogenous or endogenous bacteria. When rare organisms cause infection, exogenous sources are implicated. This sets into motion hospital infection control team searches, which are both exhausting and harassing to patients and staff. This study examines the skin bacteria present at admission and the frequency of endogenous infection in burn patients. Sixty-two patients with burns up to 92% of the total body surface area underwent unburned skin bacterial surveillance on admission and at weekly intervals using RODAC contact plates. Burn wounds were biopsied for quantitative and qualitative analyses. Morphologically dissimilar colonies were isolated and identified using standard gram-positive and gram-negative identification strips (Analytab Products, Inc. [API]). On admission, the patients harbored Staphylococcus species, many of which were burn wound sepsis were infected with the same organisms cultured from their unburned skin on admission. A subset of patients (14) grew methicillin-resistant Staphylococcus aureus from their wounds or other sites. A comparison with admission isolates showed identical susceptibilities. These data suggest skin is an endogenous source of infection in the burned patient.

Bacteria↗

An analysis of 1,423 facial fractures in 788 patients at an urban trauma center.

The hospital records of all patients presenting to a large urban trauma center emergency department with facial fractures from 1980 through 1984 were reviewed retrospectively. There were 788 patients in the study group, averaging 1.8 fractures per patient for a total of 1,423 facial fractures. The study population had 638 (80.9%) males and 150 (19.1%) females. Racial mix was 71.6% black, 27.8% white, and 0.6% oriental. The most frequent fracture involved the zygoma (23.6%), followed by the orbital floor (21.4%), maxilla, mandible, and nasal bones. The most frequent etiology was assault with a blunt object or fist (70.1%) followed by motor vehicle accidents (13.5%), falls (9.3%), and gunshot wounds (6.1%). Initial diagnostic procedures included a facial X-ray series in 99.9%, tomograms in 43.1%, and CT studies in 8.1%. Surgical intervention was required in 61.2% of cases. Prosthetic materials were used in 8.5% of the cases. At our institution, personal assault was found to be the primary cause of both midface fractures and mandibular fractures.

Adult↗

Renal medullary amyloidosis in Dorcas gazelles.

Between January 1976 and September 1987 renal medullary amyloidosis (RMA) was diagnosed in 17 Dorcas gazelles; the necropsy prevalence rate was 17/32 (53%). The most severe amyloid deposits were in the renal medulla; glomeruli were spared. Renal cortical lesions of interstitial fibrosis and tubular atrophy and dilatation significantly correlated with RMA (P less than 0.01) and were considered to be secondary changes. There were varying degrees of lymphoplasmacytic inflammation and tubular cast formation which did not significantly correlate with RMA. Amyloid was confirmed histochemically and by electron microscopy and was identified as AA type by the permanganate method. Progressive renal failure was the cause of death or necessitated euthanasia in 7/17 (41%) gazelles. RMA in Dorcas gazelles does not appear to be familial. A high prevalence of chronic or recurring Actinomyces (Corynebacterium) pyogenes infections may be an important factor.

Actinomyces↗

Adrenal-pituitary-gonadal relationships and ejaculate characteristics in captive leopards (Panthera pardus kotiya) isolated on the island of Sri Lanka.

In Study 1, semen was collected using a standardized electroejaculation procedure. Males (N = 8) produced ejaculates with a high incidence of sperm abnormalities (77 +/- 3.3%). After electroejaculation under anaesthesia, serum cortisol concentrations increased (P less than 0.05), while testosterone concentrations decreased (P less than 0.05) and LH and FSH concentrations were unchanged (P less than 0.05) over a 2-h bleeding period. In Study 2, male and female leopards were bled at 5-min intervals for 3 h and given (i.v.): (1) saline (N = 2/sex); (2) GnRH (1 microgram/kg body weight) 30 min after the onset of sampling (N = 5/sex); or (3) ACTH (250 micrograms) at 30 min followed by GnRH 1 h later (N = 5/sex). Basal concentrations of serum LH, FSH and cortisol were comparable (P greater than 0.05) between male and female leopards. After GnRH, peak LH concentrations were 2-fold greater (P less than 0.05) in males than females while FSH responses were similar. In males, testosterone concentrations increased 2-3-fold following GnRH. After ACTH, serum cortisol concentrations doubled within 15 min in both sexes. Administration of ACTH 1 h before GnRH did not affect GnRH-induced LH or FSH release (P greater than 0.05); however, testosterone secretion was only 30% of that observed after GnRH alone (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

Gangrene of the lung.

Case histories of four patients with gangrene of the lung are presented. All of these patients had characteristic radiographic features of the disease. Two patients had resection and survived. One patient who spontaneously coughed up necrotic tissue via the bronchus survived. One patient who died of an acute myocardial infarction was found at autopsy to have the characteristic pathologic findings of gangrene of the lung.

Aged↗

Biosynthetic compound dressings--management of hand burns.

To achieve optimal hand function, wound closure becomes the most important ingredient in hand burns. This study documents the use of a biosynthetic compound dressing (Biobrane) which has been fabricated as a glove for management of hand burns. The glove allowed rapid active motion and minimized the pain of open wounds. Forty-two Biobrane glove applications were evaluated with 50 per cent applied over superficial hand burns and 50 per cent over deep partial thickness or full thickness injuries. In the superficial hand burns, the patients were discharged home after a mean time of 2.8 days. With the deep burns the dressing provided a closed wound after early excision of eschar without the use of an autograft or biological dressing. Based on these studies, we conclude that the biosynthetic compound dressing glove is a useful adjunct to be added to the armamentarium for treatment of the burned hand.

Biocompatible Materials↗

Layered closure of lacerations.

The cause, depth, and location of a laceration are major determining factors in its treatment. In all cases, the wound must be completely cleansed with irrigation under pressure and then examined radiographically if necessary and debrided. Successful repair depends on understanding and using the principles of wound healing. The skin's greatest strength is in the dermal layer, and the best repair results when the entire depth of the dermis is accurately approximated to the entire depth of the opposite dermis. Accurate coaptation of the epidermis gives a polished effect to the repair but does not contribute to its strength. Fat and muscle do not support sutures. Full-thickness sutures may safely be used only on palmar and plantar surfaces. With an extensive laceration or one near a joint, a splint or sling may be needed. The wound should be examined a couple of days after suture placement for signs of infection.

Animals↗

A comparative analysis of ejaculate and hormonal characteristics of the captive male cheetah, tiger, leopard, and puma.

Male cheetahs, tigers, leopards, and pumas maintained under the same conditions were anesthetized and 1) serially bled before, during, and after electroejaculation (EE); 2) serially bled only (AO); or 3) serially bled before and after receiving adrenocorticotropin hormone (ACTH). Ejaculates from leopards contained higher (p less than 0.05) sperm concentrations than cheetahs and pumas but lower (p less than 0.05) sperm motility ratings than all other species. Tigers produced a larger seminal volume and the greatest number of motile sperm/ejaculate (p less than 0.05). The percentage of morphologically abnormal spermatozoa was greater (p less than 0.05) in cheetahs (64.6%), leopards (79.5%), and pumas (73.5%) than in tigers (37.5%). The most prevalent spermatozoal deformities included a tightly coiled or bent flagellum, a deranged midpiece, or a residual cytoplasmic droplet. Mean baseline serum cortisol concentrations in leopards were 2- and 4-fold greater (p less than 0.05) than in tigers and cheetahs, respectively. Basal cortisol concentrations in pumas were similar to those of tigers, but irrespective of treatment increased 2-fold (p less than 0.01) during the bleeding period. An acute rise and fall in cortisol attributable to EE was observed only in cheetahs. In tigers and leopards, mean peak cortisol concentrations after ACTH were similar to maximal values observed after EE. However, peak cortisol levels in cheetahs and pumas after ACTH were greater (p less than 0.01) than the concentrations measured after EE, indicating that these manipulatory procedures were not eliciting a maximal adrenal response. In the EE groups, luteinizing hormone (LH) and testosterone levels in cheetahs were lower (p less than 0.05) than in other species, whereas levels of both hormones were comparable (p greater than 0.05) in tigers, leopards, and pumas. Elevated cortisol levels in cheetahs and pumas had no discernible effect on LH/testosterone patterns; however, the results were equivocal in tigers, and, among leopards, testosterone concentrations consistently declined over time. In this study, using a standardized approach, we identify different ejaculate and endocrine characteristics of captive cheetahs, tigers, leopards, and pumas. The data extend earlier observations and demonstrate that some, but not all, Felidae species ejaculate high numbers of pleiomorphic spermatozoa. However, inter-species differences in sperm integrity do not appear related to inter-species variations in cortisol, LH, or testosterone. The observation of continuously declining testosterone concentrations only in leopards after AO, EE, or ACTH treatment suggests that rising and/or elevated cortiso

Acinonyx↗

Ovarian function in the elephant: luteinizing hormone and progesterone cycles in African and Asian elephants.

Serum samples were collected weekly for 3 yr from two female African elephants, for 18 mo from two other female African elephants, and for 2 yr from two female Asian elephants. Animals were not sedated at the time of blood collection. Ovarian cycles, characterized by changes in progesterone and immunoreactive luteinizing hormone (ILH) concentrations, averaged 15.9 +/- 0.6 wk (N = 25) for African females and 14.7 +/- 0.5 wk for Asian females (N = 10). The length of the active luteal phase averaged 10.0 +/- 0.3 wk for African elephants (range 8-14 wk) and 10.6 +/- 0.6 wk for Asian females (range 9-13 wk). Interluteal phases were 5.9 +/- 0.6 wk for African females and 4.2 +/- 0.5 wk for Asian females. One African female (Maliaca) had two extended interluteal phases, both occurring between the months of February and May. Excluding these two periods, there were no differences in the length of the ovarian cycle or the length of the luteal phase between species of elephant. Serum progesterone in both species ranged from less than 50 pg/ml to 933 pg/ml. Average progesterone concentrations during the luteal phase were significantly lower in African elephants compared with Asian elephants (328 +/- 13, N = 30 cycles vs. 456 +/- 23, N = 14 cycles; p less than 0.001). ILH ranged from nondetectable to 11.6 ng/ml. These data suggest that the length of the ovarian cycle in the African elephant is about 16 wk and confirm that the length of the ovarian cycle in the Asian elephant is about 15 wk.

Animals↗

Mortality of captive tortoises due to viviparous nematodes of the genus Proatractis (Family Atractidae).

Between September 1982 and January 1984, verminous colitis was diagnosed post mortem in eight red-footed tortoises (Geochelone carbonaria) and three leopard tortoises (Geochelone pardalis) from the reptile collection of the National Zoological Park. This represented 69% of 16 tortoise necropsy accessions for that period. Etiology was determined to be a viviparous pinworm-like nematode of the genus Proatractis (Family Atractidae). Clinical signs were either nonspecific, consisting of anorexia, lethargy, and depression, or were absent. Limited trials with piperazine citrate and fenbendazole appeared to be ineffectual against the parasite and supportive therapy was unsuccessful. Post mortem examination revealed roughening and thickening of the mucosa of the cecum and colon, and in severe cases myriads of tiny (0.5-1.0 cm) nematodes were evident on the mucosal surface. In six tortoises, worms were found also in the small intestine. Histopathologic features in severe cases included mucosal necrosis with parasites and mixed inflammatory cells extending into the tunica muscularis. Focal to diffuse lymphoplasmacytic infiltrates were present consistently in the submucosa of the cecum and colon, and similar but milder lesions occasionally occurred in the small intestine.

Animals↗