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Biomedical subjects

L G Phillips

Publications and source records attributed to L G Phillips.

At least 19 recordsLinked to original sources
PubMed2004

Immobilisation of impala (Aepyceros melampus) with a ketamine hydrochloride/medetomidine hydrochloride combination, and reversal with atipamezole hydrochloride.

A combination of medetomidine hydrochloride (medetomidine) and ketamine hydrochloride (ketamine) was evaluated in 16 boma-confined and 19 free-ranging impalas (Aepyceros melampus) to develop a non-opiate immobilisation protocol. In free-ranging impala a dose of 220 +/- 34 microg/kg medetomidine and 4.4 +/- 0.7 mg/kg ketamine combined with 7500 IU of hyaluronidase induced recumbency within 4.5 +/- 1.5 min, with good muscle relaxation, a stable heart rate and blood pH. PaCO2 was maintained within acceptable ranges. The animals were hypoxic with reduced oxygen saturation and low PaO2 in the presence of an elevated respiration rate, therefore methods for respiratory support are indicated. The depth of sedation was adequate for minor manipulations but additional anaesthesia is indicated for painful manipulations. Immobilisation was reversed by 467 +/- 108 microg/kg atipamezole hydrochloride (atipamezole) intramuscularly, but re-sedation was observed several hours later, possibly due to a low atipamezole:medetomidine ratio of 2:1. Therefore, this immobilisation and reversal protocol would subject impalas to possible predation or conspecific aggression following reversal if they were released into the wild. If the protocol is used on free-ranging impala, an atipamezole:medetomidine ratio of 5:1 should probably be used to prevent re-sedation.

Adrenergic alpha-Antagonists↗
PubMed2001

Use of medetomidine and ketamine for immobilization of free-ranging giraffes.

OBJECTIVE: To develop a dosage correlated with shoulder height (SH) in centimeters for effective immobilization of free-ranging giraffes, using a combination of medetomidine (MED) and ketamine (KET) and reversal with atipamezole (ATP). DESIGN: Prospective study. ANIMALS: 23 free-ranging giraffes. PROCEDURE: The drug combination (MED and KET) was administered by use of a projectile dart. Quality of induction, quality of immobilization, and time to recovery following injection of ATP were evaluated. Physiologic variables measured during immobilization included PaO2, PaCO2, oxygen saturation, end-tidal CO2, blood pH, indirect arterial blood pressure, heart and respiratory rates, and rectal temperature. RESULTS: Sixteen giraffes became recumbent with a dosage (mean +/- SD) of 143 +/- 29 microg of MED and 2.7 +/- 0.6 mg of KET/cm of SH. Initially, giraffes were atactic and progressed to lateral recumbency. Three giraffes required casting with ropes for data collection, with dosages of 166 +/- 5 microg of MED and 3.2 +/- 0.6 mg of KET/cm of SH. Four giraffes required administration of etorphine (n = 2) or were cast with ropes (2) for capture but remained dangerous to personnel once recumbent, precluding data collection. In giraffes successfully immobilized, physiologic monitoring revealed hypoxia and increased respiratory rates. Values for PaCO2, end-tidal CO2, and heart rate remained within reference ranges. All giraffes were hypertensive and had a slight increase in rectal temperature. Atipamezole was administered at 340 +/- 20 microg/cm of SH, resulting in rapid and smooth recoveries. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine and KET was an effective immobilizing combination for free-ranging giraffes; however, at the dosages used, it does not induce adequate analgesia for major manipulative procedures. Quality of induction and immobilization were enhanced if the giraffe was calm. Reversal was rapid and complete following injection of ATP.

Adrenergic alpha-Agonists↗
PubMed2001

Do not use epinephrine in digital blocks: myth or truth?

The purpose of this study was to examine the role for epinephrine augmentation of digital block anesthesia by safely prolonging its duration of action and providing a temporary hemostatic effect. After obtaining approval from the review board of the authors' institution, 60 digital block procedures were performed in a prospective randomized double-blinded study. The digital blocks were performed using the dorsal approach. All anesthetics were delivered to treat either posttraumatic injuries or elective conditions. Of the 60 digital block procedures, 31 were randomized to lidocaine with epinephrine and 29 to plain lidocaine. Of the procedures performed using lidocaine with epinephrine, one patient required an additional injection versus five of the patients who were given plain lidocaine (p = 0.098). The need for control of bleeding required digital tourniquet use in 20 of 29 block procedures with plain lidocaine and in 9 of 31 procedures using lidocaine with epinephrine (p < 0.002). Two patients experienced complications after plain lidocaine blocks, while no complications occurred after lidocaine with epinephrine blocks (p = 0.23). By prolonging lidocaine's duration of action, epinephrine may prevent the need for an additional injection and prolong post-procedure pain relief. This study demonstrated that the temporary hemostatic effect of epinephrine decreased the need for, and thus the potential risk of, using a digital tourniquet (p < 0.002). As the temporary vasoconstrictor effect is reversible, the threat of complication from vasoconstrictor-induced ischemia is theoretical.

Contraindications↗
PubMed2001

Chronic otitis externa/media with total ear canal ablation and bulla curettage in a North American bison (Bison bison).

An adult female North American bison (Bison bison) with a chronic otitis externa/media of the right ear was examined because of a 4-mo history of intermittent anorexia, apparent painful behavior, and auricular discharge from the right ear. Computerized tomography (CT) demonstrated osteolysis of the tympanic, petrous, and squamous aspects of the temporal bone with soft tissue replacement and sclerosis of the right bulla. A total ear canal ablation with bulla curettage was performed, and cefazolin-impregnated polymethacrylate beads were left within the right bulla and the remnant temporal bone. Six months after the surgery, the bison had no clinical signs of otitis media.

Animals↗
PubMed2000

Transfer of platelet-derived growth factor-BB gene by gene gun increases contraction of collagen lattice by fibroblasts in diabetic and non-diabetic human skin.

We have used an in vitro model of wound contraction, the fibroblast-populated collagen lattice, to examine the effect of platelet-derived growth factor BB (PDGF-BB) and PDGF-BB gene transfer by gene gun on the contraction of lattices composed of either diabetic or non-diabetic human fibroblasts. The area of collagen lattice and DNA synthesis were measured in 12 specimens. There were significant increases in lattice contraction with increasing doses of PDGF-BB and fibroblasts transfected with the PDGF-BB gene compared with control (p < 0.01). DNA synthesis of the non-diabetic and diabetic fibroblast lattices showed significantly increased incorporation of tritiated thymidine with increasing doses of PDGF-BB and fibroblasts transfected with the PDGF-BB compared with controls (p < 0.05). The effect of PDGF-BB gene transfer on diabetic and non-diabetic fibroblasts was similar to that of 20 ng/ml or less of PDGF-BB.

Becaplermin↗
PubMed2000

Bipedicle paraspinous muscle flaps for spinal wound closure: an anatomic and clinical study.

The purpose of this study was to evaluate the vascular anatomy of the paraspinous muscles and review their clinical use as bipedicled flaps in spinal wound closure. Anatomically, through cadaver dissections, lead oxide injections, and radiographic imaging, the blood supply to the paraspinous muscles was determined. Clinically, 29 consecutive patients treated with spinal wounds and exposed bone or hardware were reviewed retrospectively. Of these patients, 19 underwent closure in delayed primary fashion, whereas 10 were referred to plastic surgery for reconstruction because of the complex nature of their wounds. The cadaver study demonstrated the paraspinous muscles to possess a segmental arterial supply through medial and lateral perforators. Division of the medial perforators allowed for medial advancement of the muscles. Lead oxide injection of the lateral perforators demonstrated adequate medial muscle perfusion with ligation of the medial perforators. Ten of the 29 patients (six women, four men, 32 to 62 years of age) were reconstructed with paraspinous (eight), latissimus (one), and trapezius (one) muscle flaps. A higher complication rate was found in wounds closed in delayed primary fashion (13 of 19 patients, 68 percent) than those reconstructed with muscle flaps (2 of 10 patients, 20 percent) (p = 0.021). Follow-up of the muscle flap reconstructed patients averaged 12 months (range, 3 to 27 months). Cadaver muscle injections predicted and clinical cases confirmed that the paraspinous muscles can be raised on lateral perforators and advanced medially to close lumbar spine wounds reliably with fewer complications.

Adult↗
PubMed1999

The effect of denervation on leukocyte function in soft tissue infection.

BACKGROUND: The present study was undertaken to investigate the effect of denervation on leukocyte function in soft-tissue infection in an isolated in vivo ovine flap model. METHODS: Fifteen adult ewes were divided into three groups. An island pedicle flap was raised on the right buttock. In group I (no denervation), the cutaneous nerve remained intact, whereas in group II (acute denervation) the nerve was divided acutely. In group III (prolonged denervation) the nerve was divided 7 days before flap elevation. All flaps received intradermal inoculation of 10(7) Staphylococcus aureus, and the animals were observed for 96 hours. RESULTS: In both groups II and III, the leukocyte chemiluminescence and chemotaxis were significantly decreased when compared with group I. Furthermore, there was profound impairment of leukocyte functions in group III compared with group II. Group III also had significantly higher bacterial counts, larger septic foci, lower viable leukocyte ratios, and decreased bacterial killing compared with group I. CONCLUSIONS: Denervation, particularly over a period of time, results in increased bacterial growth of soft-tissue septic foci. This appears to be due to decreased leukocyte function resulting in diminished bacterial killing.

Animals↗
PubMed1999

Modified Dakin's solution for cutaneous vibrio infections.

Vibrio species, specifically Vibrio vulnificus, are known to be endemic to warm saltwater environments. As a human pathogen they are capable of causing severe, progressive, necrotizing infections. The lesions are bullous in nature and often require wide surgical debridement due to the aggressiveness of this organism. The literature supports prophylactic antibiotic therapy for those with preexisting hepatic dysfunction or immunocompromise. The authors routinely implement prophylactic antibiotic coverage with doxycycline 100 mg every 12 hours for vibrio in patients with wounds exposed to or acquired in saltwater. In addition, they institute topical therapy with 0.025% sodium hypochlorite solution (modified Dakin's), based on their in vitro study of vibrio sensitivity to antimicrobials. Over the past 2 years, the authors have treated 10 patients with this protocol for cutaneous vibrio infections confirmed by quantitative cultures. None of these patients experienced progression of infection requiring operative debridement-contrary to the aggressive nature of this organism documented in other reports.

Adolescent↗
PubMed1999

A model for the assessment of sensory recovery of experimental skin grafts.

The return of sensation to skin grafts is often suboptimal. Although the reinnervation of skin grafts has been examined by a number of authors during the past century, studies in humans have left a number of unanswered issues, whereas animal studies have been largely confined to histological work and a few electrophysiological studies. Based on knowledge that rats exhibit a reflexive flick of the back skin in response to stimulation, the authors hypothesized that it should be possible to develop a noninvasive model for assessing return of sensation in experimental skin grafts. Full-thickness skin grafts were created, one per animal, on the dorsa of male Sprague-Dawley rats. Sensory testing was performed using a hand-held pinprick device designed to deliver a stimulus of reproducible force. A positive response was observed as a flick of the dorsal skin--a very reliable reflex involving the cutaneus trunci muscle. The stimulus was delivered to each of 25 sectors of the graft on days 9, 13, 16, 20, 40, 60, and 110 postoperatively. Results were analyzed regarding the percentage of grafts responding at each time point as well as the topographical pattern of sensory return. Evidence of sensation was first detected at day 13 at the margins of the skin grafts and then progressed centrally until homogenous reinnervation (94% of the graft surface) was observed at day 40 and was maintained through the end of the study. Growth Associated Protein (GAP)-43 immunostaining was used to document reinnervation of the skin grafts histologically.

Animals↗
PubMed1999

Another indication for liposuction: small facial lipomas.

The treatment of facial lipomas at times requires the use of incisions that are less than satisfactory in either size or location. In an effort to minimize scarring, the authors have been removing these lesions with liposuction. The purpose of this study was to review the authors' experience in treating small facial lipomas using liposuction. Over the last 10 years, the authors treated five patients with forehead lipomas by removal with liposuction through hair-bearing scalp incisions. All patients were evaluated after the procedure for bleeding, paresthesias, recurrence, scarring, and overall satisfaction with the procedure. All of these patients had lipomas that measured 4 cm or less at the time of surgery. No patient experienced hematoma, nerve injury, or recurrence. All patients were completely satisfied with their result and scar. The literature describes an advantage to using liposuction for the treatment of medium (4 to 10 cm) and large (>10 cm) lipomas. Because small lipomas (<4 cm) can be extracted through small incisions, the literature reports no advantage to removal with liposuction. However, favorable aesthetic results can be obtained by removing small facial lipomas with liposuction through strategically placed incisions.

Adult↗
PubMed1999

Langer's lines: to use or not to use.

Thirty-six differently named guidelines have developed as surgeons have searched for an ideal guide for elective incisions. Many surgeons prefer Langer's lines. These lines were developed by Karl Langer, an anatomy professor, from cadavers in rigor mortis. However, Kraissl preferred lines oriented perpendicular to the action of the underlying muscles. Later, Borges described relaxed skin tension lines, which follow furrows formed when the skin is relaxed and are produced by pinching the skin. However, these are only guidelines; there are many contributors to the camouflaging of scars, including wrinkle and contour lines. Borges's and Kraissl's lines (not Langer's) may be the best guides for elective incisions of the face and body, respectively.

Anatomy↗
PubMed1998

An emergency multisystem screw removal module.

There are several practical indications for the removal of screws and plates from the reconstructive patient. For the craniomaxillofacial surgeon there exists a wide array of screw and plating systems available. As patients relocate, it is unlikely that individual hospitals have the full collection of rigid fixation systems in their inventory. Therefore, a universal screw removal system was designed to facilitate the elective and emergency removal of all existing craniomaxillofacial fixation hardware. This system is a self-contained module containing a single handle and 12 interchangeable screwdriver blades. The universal screw and plate removal system has been used successfully in several patients--children as well as adults--in whom hardware was removed.

Bone Screws↗
PubMed1998

Tamoxifen downregulates TGF-beta production in keloid fibroblasts.

Keloids occur only in humans and are characterized by fibroblast overproduction of collagen types I and III. Keloid fibroblasts have been shown to make elevated levels of transforming growth factor beta (TGF-beta), a growth factor known to promote extracellular matrix production and fibrosis. Thus, the pathophysiology underlying keloid formation may be driven by the biological activity of TGF-beta. Tamoxifen, a synthetic, nonsteroidal antiestrogen has been shown to inhibit keloid fibroblast proliferation and decrease collagen production. The purpose of this study was to determine if a mechanism by which tamoxifen decreases keloid collagen production is through a downregulation of TGF-beta. Through a luciferase TGF-beta bioassay we found that 4 microM of tamoxifen generated a 49% reduction in total TGF-beta activity and 8 microM generated an 85% reduction compared with controls. Thus we propose that one of the mechanisms by which tamoxifen decreases keloid fibroblast collagen synthesis is by decreasing TGF-beta production.

Cell Culture Techniques↗
PubMed1998

Creep vs. stretch: a review of the viscoelastic properties of skin.

Possessing viscous and elastic rheological properties, skin is viscoelastic. Mechanical creep, defined as the elongation of skin with a constant load over time beyond intrinsic extensibility, has been described as the vehicle harnessed for wound closure with presuturing, intraoperative tissue expansion, skin-stretching devices, and skin retraction with undermining. Resulting from the generation of new tissue due to a chronic stretching force, biological creep plays a role in conventional tissue expansion.

Biomechanical Phenomena↗
PubMed1998

Epinephrine in digital blocks: revisited.

Digital block anesthesia with epinephrine, ring technique, and digital tourniquet have been implicated in causing finger gangrene. An extensive review of the literature provided no case of finger gangrene attributed solely to the adjunctive use of epinephrine with lidocaine for digital block. By causing vasoconstriction, epinephrine complements the local analgesic by prolonging the duration of action and providing a temporary hemostatic effect. Epinephrine augmentation of digital block anesthesia was used in the treatment of 23 finger injuries without a complication.

Adolescent↗
PubMed1998

Bartonella henselae antibody prevalence in free-ranging and captive wild felids from California.

In order to determine the importance of wild felids in the epidemiology of Bartonella spp. infection, 136 Nobuto strips or serum samples from free-ranging mountain lions (Felis concolor) and bobcats (Felis rufus) captured in California (USA) between 1985 and 1996 were tested for B. henselae antibodies (titer > or = 1:64) using an immunofluorescence test. Similarly, 124 serum samples from 114 captive wild cats representing 26 species or subspecies collected between 1991 and 1995 were retrieved from the serum banks of four California zoological parks. Fifty-three percent (33/62) of the bobcats, 35% (26/74) of the mountain lions, and 30% (34/114) of the captive wild felids (genera Acinonyx, Panthera and Felis) had B. henselae antibodies. In captive wild felids, prevalence varied widely among the species, but seropositivity was more likely to occur in the genus Felis than in the genus Acinonyx or Panthera. Prevalence was evenly distributed between sexes, except for free-ranging mountain lions. Antibody prevalence ranged from 25% in 0- to 2-yr-old captive felids to 35% in cats > or = 9-yr-old, but the highest antibody titers were observed in cats < 5-yr-old.

Age Factors↗
PubMed1997

Containment of a multiresistant Serratia marcescens outbreak.

A 3-year-old male from Bolivia who sustained a full-thickness 80 per cent TBSA burn complicated by smoke inhalation on the 28 March 1995 was admitted to our burn centre on 6 April 1995. On 11 April the patient's wounds were colonized with a Serratia marcescens sensitive only to ciprofloxacin and imipenem. Sputum cultures revealed the same phenotypic S. marcescens. Two patients who were admitted days later had the same phenotypic S. marcescens. Their TBSA burns ranged from 54 to 80 per cent. Both were injured in early April. Sputum and wound cultures were also positive for S. marcescens. Precautionary measures were instituted immediately. All potential reservoirs were cultured. Cultures were negative for S. marcescens. Patient therapy was maintained via strict isolation. The first patient died on 17 May. The two remaining patients survived and were discharged colonized with S. marcescens. However, the biotype of the initial S. marcescens was different from the latter two. Early recognition of a multiresistant S. marcescens resulted in negating the spread of this agent to other patients.

Adolescent↗