Search PubMed⌕ Search

Biomedical subjects

David G Armstrong

Publications and source records attributed to David G Armstrong.

At least 37 records · Page 2Linked to original sources
PubMed2005

Evaluation of removable and irremovable cast walkers in the healing of diabetic foot wounds: a randomized controlled trial.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of a removable cast walker (RCW) and an "instant" total contact cast (iTCC) in healing neuropathic diabetic foot ulcerations. RESEARCH DESIGN AND METHODS: We randomly assigned 50 patients with University of Texas grade 1A diabetic foot ulcerations into one of two off-loading treatment groups: an RCW or the same RCW wrapped with a cohesive bandage (iTCC) so patients could not easily remove the device. Subjects were evaluated weekly for 12 weeks or until wound healing. RESULTS: An intent-to-treat analysis showed that a higher proportion of patients had ulcers that were healed at 12 weeks in the iTCC group than in the RCW group (82.6 vs. 51.9%, P = 0.02, odds ratio 1.8 [95% CI 1.1-2.9]). Of the patients with ulcers that healed, those treated with an iTCC healed significantly sooner (41.6 +/- 18.7 vs. 58.0 +/- 15.2 days, P = 0.02). CONCLUSIONS: Modification of a standard RCW to increase patient adherence to pressure off-loading may increase both the proportion of ulcers that heal and the rate of healing of diabetic neuropathic wounds.

Casts, Surgical↗
PubMed2005

A randomized trial of two irremovable off-loading devices in the management of plantar neuropathic diabetic foot ulcers.

OBJECTIVE: The purpose of this study was to compare the effectiveness of a removable cast walker (RCW) rendered irremovable (iTCC) with the total contact cast (TCC) in the treatment of diabetic neuropathic plantar foot ulcers. RESEARCH DESIGN AND METHODS: In a prospective, randomized, controlled trial, 41 consecutive diabetic patients with chronic, nonischemic, neuropathic plantar foot ulcers were randomly assigned to one of two groups: a RCW rendered irremovable by wrapping it with a single layer of fiberglass casting material (i.e., an iTCC) or a standard TCC. Primary outcome measures were the proportion of patients with ulcers that healed at </=12 weeks, healing rates, complication rates, cast placement/removal times, and costs. RESULTS: The proportions of patients with ulcers that healed within 12 weeks in the iTCC and TCC groups were 80 and 74%, respectively (94 and 93%, respectively, when patients who were lost to follow-up were excluded). Survival analysis (healing rates) was statistically equivalent in the two groups, as were complication rates, but with a trend toward benefit in the iTCC group. The iTCC took significantly less time to place and remove than the TCC with 39% and 36% reductions, respectively. There was also an overall lower cost associated with the use of the iTCC compared with the TCC. CONCLUSIONS: The iTCC may be equally efficacious, faster to place, easier to use, and less expensive than the TCC in the treatment of diabetic plantar neuropathic foot ulcers.

Adult↗
PubMed2004

It's not what you put on, but what you take off: techniques for debriding and off-loading the diabetic foot wound.

The basic etiology of neuropathic diabetic foot wounds involves pressure in conjunction with cycles of repetitive stress, leading to failure of skin and soft tissue. The central tenet of any treatment plan addressing neuropathic diabetic foot wounds is the appropriate debridement of nonviable tissue coupled with adequate pressure relief (off-loading). Although numerous advances have been made in the treatment of diabetic foot wounds, including bioengineered tissues, autologous and exogenous cytokine delivery systems, and potentially effective topical antimicrobial modalities, none will succeed without addressing effective debridement and off-loading. Specific debridement and off-loading techniques are discussed, along with available supporting evidence. This includes the use of the "instant" total contact cast, among other modalities.

Debridement↗
PubMed2004

Expression of messenger ribonucleic acid encoding for steroidogenic acute regulatory protein and enzymes, and luteinizing hormone receptor during the spring transitional season in equine follicles.

The period of spring transition, from the anovulatory to the ovulatory season, is characterized in many mares by cyclical growth and regression of large dominant follicles. These follicles produce only low concentrations of estradiol and it is thought that acquisition of steroidogenic competence by large follicles during spring transition is prerequisite in stimulating LH prior to first ovulation. In situ hybridization was used to localize and quantify expression of factors that play a key role in follicular steroidogenesis: StAR, P450scc (CYP11A1), P450c17 (CYP17), P450arom (CYP19), and LH receptor (LHr). One ovary was obtained from mares on the day after detection of an actively growing 30 mm transitional anovulatory follicle (defined as the transitional follicle), and the remaining ovary was removed at the third estrus of the breeding season on the day after the preovulatory follicle reached 30 mm in diameter (defined as the preovulatory follicle). Messenger RNAs encoding StAR, CYP11A1, and CYP17 were detected only in theca cells and CYP19 mRNA was confined to the granulosa layer. There was significantly lower expression of mRNAs for the steroidogenic enzymes, StAR (P<0.001) and LHr (P<0.05) in transitional follicles than in preovulatory follicles. In conclusion, large equine follicles during spring transition have low levels of mRNA encoding steroidogenic enzymes, StAR and LHr which will contribute to the steroidogenic incompetence of dominant follicles during spring transition and their subsequent regression.

Animals↗
PubMed2004

Advances in the treatment of diabetic foot infections.

Lower extremity infections are frequent causes of substantial morbidity and mortality in the diabetic population, and these infections consume a large portion of resources expended on diabetic complications. Gram-positive cocci, particularly Staphylococcus aureus, are the most important pathogens in diabetic foot infections. These organisms are predominant both in mild infections (which are often monomicrobial), as well as in more severe and chronic infected wounds that more often have a polymicrobial cause. Appropriate clinical assessment and culturing of infections are critical in establishing the presence and severity of infection, in detecting osteomyelitis, and in directing the optimal treatment approach. Following necessary debridement and other surgical interventions (e.g., bone resection, revascularization), appropriate antibiotic therapy is a cornerstone of managing the infected lower extremity. Peripheral vascular (i.e., arterial) insufficiency and the increasing prevalence of antibiotic resistance are primary barriers to successfully managing these infections. Fortunately, alternative delivery systems (e.g., antibiotic beads, impregnated sponges) and novel antibiotics (e.g., levofloxacin, linezolid) are providing possible solutions to the challenges posed by this physically, emotionally, and financially devastating condition.

Anti-Bacterial Agents↗
PubMed2004

Diabetic foot infections: stepwise medical and surgical management.

Foot complications are common among diabetic patients; foot ulcers are among the more serious consequences. These ulcers frequently become infected, with potentially disastrous progression to deeper spaces and tissues. If not treated promptly and appropriately, diabetic foot infections can become incurable or even lead to septic gangrene, which may require foot amputation. Diagnosing infection in a diabetic foot ulcer is based on clinical signs and symptoms of inflammation. Properly culturing an infected lesion can disclose the pathogens and provide their antibiotic susceptibilities. Specimens for culture should be obtained after wound debridement to avoid contamination and optimise identification of pathogens. Staphylococcus aureus is the most common isolate in these infections; the increasing incidence of methicillin-resistant S. aureus over the past two decades has further complicated antibiotic treatment. While chronic infections are often polymicrobial, many acute infections in patients not previously treated with antibiotics are caused by a single pathogen, usually a gram-positive coccus. We offer a stepwise approach to treating diabetic foot infections. Most patients must first be medically stabilised and any metabolic aberrations should be addressed. Antibiotic therapy is not required for uninfected wounds but should be carefully selected for all infected lesions. Initial therapy is usually empirical but may be modified according to the culture and sensitivity results and the patient's clinical response. Surgical intervention is usually required in cases of retained purulence or advancing infection despite optimal medical therapy. Possible additional indications for surgical procedures include incision and drainage of an abscess, debridement of necrotic material, removal of any foreign bodies, arterial revascularisation and, when needed, amputation. Most foot ulcers occur on the plantar surface of the foot, thus requiring a plantar incision for any drainage procedure.

Amputation, Surgical↗
PubMed2004

Gamma-irradiated human skin allograft: a potential treatment modality for lower extremity ulcers.

Gamma-irradiated human skin allograft consists of epidermis and dermis. Unlike bioengineered tissues which require cold storage and timely use once received from the manufacturer, gamma-irradiated human skin allograft can be stored for as long as 24 months at room temperature. This modality is applied in a fashion similar to that of bioengineered skin grafts. In this article, we present case studies with concise reviews of the available evidence to discuss the potential use of gamma-irradiated human skin allograft on wounds in the lower extremity.

Aged↗
PubMed2004

Decreasing foot pressures while implementing topical negative pressure (vacuum-assisted closure) therapy.

Over the past generation, there have been a number of significant advances in wound healing in general. Unfortunately, much of this has not translated into increased success in healing wounds on the sole of the foot. We believe that much of this therapeutic disconnect has to do with an inadequate merging of pressure off-loading technologies and active wound-healing technologies. This article discusses such a merger between removable cast walkers and topical negative pressure (also known as vacuum-assisted closure).

Journal Article↗
PubMed2004

Home monitoring of foot skin temperatures to prevent ulceration.

OBJECTIVE: To evaluate the effectiveness of at-home infrared temperature monitoring as a preventative tool in individuals at high risk for diabetes-related lower-extremity ulceration and amputation. RESEARCH DESIGN AND METHODS: Eighty-five patients who fit diabetic foot risk category 2 or 3 (neuropathy and foot deformity or previous history of ulceration or partial foot amputation) were randomized into a standard therapy group (n = 41) or an enhanced therapy group (n = 44). Standard therapy consisted of therapeutic footwear, diabetic foot education, and regular foot evaluation by a podiatrist. Enhanced therapy included the addition of a handheld infrared skin thermometer to measure temperatures on the sole of the foot in the morning and evening. Elevated temperatures (>4 degrees F compared with the opposite foot) were considered to be "at risk" of ulceration due to inflammation at the site of measurement. When foot temperatures were elevated, subjects were instructed to reduce their activity and contact the study nurse. Study subjects were followed for 6 months. RESULTS: The enhanced therapy group had significantly fewer diabetic foot complications (enhanced therapy group 2% vs. standard therapy group 20%, P = 0.01, odds ratio 10.3, 95% CI 1.2-85.3). There were seven ulcers and two Charcot fractures among standard therapy patients and one ulcer in the enhanced therapy group. CONCLUSIONS: These results suggest that at-home patient self-monitoring with daily foot temperatures may be an effective adjunctive tool to prevent foot complications in individuals at high risk for lower-extremity ulceration and amputation.

Diabetes Complications↗
PubMed2004

Variability in activity may precede diabetic foot ulceration.

OBJECTIVE: To evaluate the role of activity in the development of neuropathic foot ulceration in individuals with diabetes. RESEARCH DESIGN AND METHODS: We evaluated the first 100 consecutive individuals with diabetes (95.0% male, aged 68.5 +/- 10.0 years with concomitant neuropathy, deformity, and/or a history of lower-extremity ulceration/partial foot amputation) enrolled in an ongoing prospective longitudinal activity study. Subjects used a high-capacity continuous computerized activity monitor. Data were collected continuously over a minimum of 25 weeks (or until ulceration) with daily activity units expressed as means +/- SD. RESULTS: Eight subjects ulcerated during the evaluation period of 37.1 +/- 12.3 weeks. The average daily activity was significantly lower in individuals who ulcerated compared with individuals who did not ulcerate (809.0 +/- 612.2 vs. 1,394.5 +/- 868.5, P = 0.03). Furthermore, there was a large difference in variability between groups. The coefficient of variation was significantly greater in the ulceration group compared with the no ulceration group (96.4 +/- 50.3 vs. 44.7 +/- 15.4%, P = 0.0001). In the 2 weeks preceding the ulcerative event, the coefficient of variation increased even further (115.4 +/- 43.0%, P = 0.02), but there was no significant difference in average daily activity during that period (P = 0.5). CONCLUSIONS: The results of this study suggest that individuals with diabetes who develop ulceration may actually have a lower overall activity than their counterparts with no ulceration, but the quality of that activity may be more variable. Perhaps modulating the "peaks and valleys" of activity in this population through some form of feedback might prove to reduce risk for ulceration in this very-high-risk population.

Activities of Daily Living↗
PubMed2004

Guidelines regarding negative wound therapy (NPWT) in the diabetic foot.

The purpose of these guidelines is to the summarize consensus of a multidisciplinary expert advisory panel convened to determine appropriate use of negative pressure wound therapy (NPWT), also known as Vacuum-Assisted Closure or V.A.C. Therapy, in the treatment of diabetic foot wounds. The Tucson Expert Consensus Conference (TECC) on V.A.C. Therapy was convened in an effort to guide the direction for future research either to confirm or refute current consensus while providing practical guidance to the clinician currently treating diabetic foot wounds. The consensus committee discussed and commented on the following ten key questions regarding NPWT: 1) How long should NPWT be used in the treatment of a diabetic foot wound? 2) Should NPWT be applied to a wound that has not been debrided? 3) How should the patient using NPWT be evaluated on an outpatient basis? 4) When should NPWT be applied following lower-extremity bypass? 5) When should NPWT be applied after incision and drainage of infection? 6) How should NPWT be used in patients with osteomyelitis? 7) How should nonadherence (i.e., noncompliance) be defined in the patient on NPWT? When should NPWT be discontinued in this population? 8) How should NPWT be used in combination with other modalities? 9) Should small, superficial, noninfected wounds be considered for NPWT? 10) How should we define success in future studies of NPWT?

Contraindications↗
PubMed2003

Activin promotes oocyte development in ovine preantral follicles in vitro.

Activins have been implicated as important regulating factors for many reproductive processes. The aim of this study was to determine the effect of activin A on the development of ovine preantral follicles in vitro. Mechanically isolated preantral follicles (161 +/- 2 microm) were cultured for 6 days in the presence of human recombinant activin A (0, 10 and 100 ng/ml). Half of the medium was replaced every second day and follicle diameters were measured. Conditioned medium was subsequently analysed for oestradiol content using a delayed enhancement lanthanide fluorometric immunoassay (DELFIA). At the end of the culture period, follicles were fixed and processed for histology, after which oocyte diameter and granulosa cell death were measured. There was significant follicle growth over 6 days in all groups (p < 0.001). Activin, at both concentrations, increased follicle growth over control levels by Day 6 (p < 0.05). Oocyte diameters were also significantly increased by Day 6 of culture in all groups (p < 0.05), with 100 ng/ml activin increasing oocyte diameter over control levels (p < 0.05). Activin, at both concentrations, increased oestradiol production on Day 2 of culture, but this increase was not sustained during the culture period. Moreover, activin did not have any effect on antrum formation or follicle survival. In conclusion, activin promoted ovine preantral follicle and oocyte growth in vitro, but did not accelerate follicle differentiation over a six-day culture period. These results support a paracrine role for activin A during early oocyte and follicular development.

Activins↗
PubMed2003

Outcomes of hyaluronan therapy in diabetic foot wounds.

The purpose of this study was to evaluate outcomes of persons with neuropathic diabetic foot wounds treated with a hyaluronan-containing dressing. Data were abstracted for 36 patients with diabetes, 72.2% male, aged 60.0+/-10.7 years and a mean glycated hemoglobin (HbA(1c)) of 9.5+/-2.5% presenting for care at two large, multidisciplinary wound care centers. All patients received surgical debridement for their diabetic foot wounds and were placed on therapy consisting of hyaluronan dressing (Hyalofill, Convatec, USA) with dressing changes taking place every other day. Outcomes evaluated included time to complete wound closure and proportion of patients achieving wound closure in 20 weeks. Hyalofill therapy was used until the wound bed achieved 100% granulation tissue. Therapy was then followed by a moisture-retentive dressing until complete epithelialization. In total, 75.0% of wounds measuring a mean 2.2+/-2.2 cm(2) healed in the 20-week evaluation period. Of those that healed in this period, healing took place in a mean 10.0+/-4.8 weeks. The average duration of Hyalofill therapy in all patients was 8.6+/-4.2 weeks. Deeper (UT Grade 2A) wounds were over 15 times less likely to heal than superficial (1A) wounds (94.7 vs. 52.9%, Odds Ratio=15.9, 95% Confidence Interval=1.7-142.8, P=0.006). We conclude that a regimen consisting of moist wound healing using hyaluronan-containing dressings may be a useful adjunct to appropriate diabetic foot ulcer care. We await the completion of a multicenter randomized controlled trial in this area to either support or refute this initial assessment.

Adjuvants, Immunologic↗
PubMed2003

Clinical efficacy of the first metatarsophalangeal joint arthroplasty as a curative procedure for hallux interphalangeal joint wounds in patients with diabetes.

OBJECTIVE: To evaluate the safety and efficacy of first metatarsophalangeal joint arthroplasty compared with standard, nonsurgical management of wounds at the plantar hallux interphalangeal joint in patients with diabetes. RESEARCH DESIGN AND METHODS: We evaluated 41 patients with ulcers classified as University of Texas Grade 1A or 2A at the plantar aspect of the hallux interphalangeal joint using a case-control model [correction]. Case subjects were patients treated with resectional arthroplasty and control subjects received standard nonsurgical care. Both groups received standard off-loading and wound care. Outcomes included time to healing, reulceration, infection, and amputation. RESULTS: The surgery group healed significantly faster than patients in the standard therapy group (standard 67.1 +/- 17.1 versus surgery 24.2 +/- 9.9 days, P = 0.0001), and they had fewer recurrent ulcers (standard 35.0 versus surgery 4.8%, P = 0.02, odds ratio 7.6, 95% CI 1.1-261.7) Both groups had similar rates of infection (standard 38.1 versus surgery 40.0%, P = 0.9) and amputation (standard 10.0 versus surgery 4.8%, P = 0.5). CONCLUSIONS: Results suggest that resectional arthroplasty is a safe and effective procedure to treat wounds of the plantar hallux compared with nonsurgical therapy.

Age of Onset↗
PubMed2003

Predictive value of foot pressure assessment as part of a population-based diabetes disease management program.

OBJECTIVE: To evaluate the effectiveness of dynamic plantar pressure assessment to determine patients at high risk for neuropathic ulceration. In choosing the cut point, we looked for an optimum combination of sensitivity and specificity of plantar pressure to screen for neuropathic ulceration. RESEARCH DESIGN AND METHODS: A total of 1,666 consecutive individuals with diabetes (50.3% male) presenting to a large urban managed care-based outpatient clinic were enrolled in this longitudinal 2-year outcome study. Patients received a standardized medical and musculoskeletal assessment at the time of enrollment, including evaluation in an onsite gait laboratory. RESULTS: Of the entire population, 263 patients (15.8%) either presented with or developed an ulcer during the 24-month follow-up period. As expected, baseline peak plantar pressure was significantly higher in the ulcerated group than in the group who did not ulcerate (95.5 +/- 26.4 vs. 85.1 +/- 27.3 N/cm(2), P < 0.001). There was also a trend toward increased pressure with increasing numbers of foot deformities, as well as with increasing foot risk classification (P = 0.0001). Peak pressure was not a suitable diagnostic tool by itself to identify high-risk patients. After eliminating patients without loss of protective sensation, using receiver operating characteristic (ROC) analysis, the optimal cut point, as determined by a balance of sensitivity and specificity, was 87.5 N/cm(2), yielding a sensitivity of 63.5% and a specificity of 46.3%. CONCLUSIONS: The data from this evaluation continue to support the notion that elevated foot pressure is an important risk factor for foot complications. However, the ROC analysis suggests that foot pressure is a poor tool by itself to predict foot ulcers.

Aged↗