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Biomedical subjects

D G Armstrong

Publications and source records attributed to D G Armstrong.

At least 55 records · Page 3Linked to original sources
PubMed2000

The potential benefits of advanced therapeutic modalities in the treatment of diabetic foot wounds.

This article discusses the advantages and disadvantages of primary wound healing as compared with primary amputation in individuals with chronic diabetic foot wounds. The authors review the potential benefits of vascular surgical procedures and advanced dressings, including two of the most promising modalities in modern wound care: growth factors and bioengineered skin. In this era of cost-conscious health-care administration, it is incumbent on the practitioner to consider not only the basic science of wound care, but also the economic aspect of treatment rendered. These various interventions, dressings, growth factor delivery systems, and new modalities could significantly reduce healing time, thereby reducing the risk of infection, hospitalization, and amputation while improving quality of life. If so, they may be truly cost-effective.

Bandages↗
PubMed2000

Expression of mRNA encoding insulin-like growth factors I and II and the type 1 IGF receptor in the bovine corpus luteum at defined stages of the oestrous cycle.

Previous studies have implicated insulin-like growth factors I and II (IGF-I and -II), in the regulation of ovarian function. The present study investigated the localization of mRNA encoding IGF-I and -II and the type 1 IGF receptor using in situ hybridization to determine further the roles of the IGFs within the bovine corpus luteum at precise stages of the oestrous cycle. Luteal expression of mRNA encoding IGF-I and -II and the type 1 IGF receptor was detected throughout the oestrous cycle. The expression of IGF-I mRNAvaried significantly during the oestrous cycle. IGF-I mRNA concentrations were significantly higher on day 15 than on day 10, and IGF-I mRNA in the regressing corpus luteum at 48 h after administration of exogenous prostaglandin was significantly greater than in the early or mid-luteal phase (days 5 and 10). In contrast, there was no significant effect of day of the oestrous cycle on expression of mRNA for IGF-II and the type 1 IGF receptor in the corpus luteum. Expression of IGF-II mRNA was localized to a subset of steroidogenic luteal cells and was also associated with cells of the luteal vasculature. mRNA encoding the type 1 IGF receptor was widely expressed in a pattern indicative of expression in large and small luteal cells. These data demonstrate that the bovine corpus luteum is a site of IGF production and reception throughout the luteal phase. Furthermore, this study highlights the potential of IGF-II in addition to IGF-I in the autocrine and paracrine regulation of luteal function.

Analysis of Variance↗
PubMed2000

Diabetic foot disorders. A clinical practice guideline. For the American College of Foot and Ankle Surgeons and the American College of Foot and Ankle Orthopedics and Medicine.

Foot ulcerations, infections, and Charcot neuropathic osteoarthropathy are three serious foot complications of diabetes mellitus that can too frequently lead to gangrene and lower limb amputation. Consequently, foot disorders are one of the leading causes of hospitalization for persons with diabetes and can account for expenditures in the billions of dollars annually in the U.S. alone. Although not all foot complications can be prevented, dramatic reductions in their frequency have been obtained through the implementation of a multidisciplinary team approach to patient management. Using this concept, the authors present a Clinical Practice Guideline for diabetic foot disorders based on currently available evidence. The underlying pathophysiology and treatment of diabetic foot ulcers, infections, and the diabetic Charcot foot are thoroughly reviewed. Although these guidelines cannot and should not dictate the standard of care for all affected patients, they are intended to provide evidence-based guidance for general patterns of practice. The goal of a major reduction in diabetic limb amputations is certainly possible if these concepts are embraced and incorporated into patient management protocols.

Arthropathy, Neurogenic↗
PubMed2000

Diabetic foot disorders: a clinical practice guideline. American College of Foot and Ankle Surgeons.

Foot ulcerations, infections, and Charcot neuropathic osteoarthropathy are three serious foot complications of diabetes mellitus that can too frequently lead to gangrene and lower limb amputation. Consequently, foot disorders are one of the leading causes of hospitalization for persons with diabetes and can account for expenditures in the billions of dollars annually in the U.S. alone. Although not all foot complications can be prevented, dramatic reductions in their frequency have been obtained through the implementation of a multidisciplinary team approach to patient management. Using this concept, the authors present a Clinical Practice Guideline for diabetic foot disorders based on currently available evidence. The underlying pathophysiology and treatment of diabetic foot ulcers, infections, and the diabetic Charcot foot are thoroughly reviewed. Although these guidelines cannot and should not dictate the standard of care for all affected patients, they are intended to provide evidence-based guidance for general patterns of practice. The goal of a major reduction in diabetic limb amputations is certainly possible if these concepts are embraced and incorporated into patient management protocols.

Amputation, Surgical↗
PubMed1999

Diabetes-related lower-extremity amputations disproportionately affect Blacks and Mexican Americans.

BACKGROUND: We sought to identify the age-adjusted incidence of lower-extremity amputation (LEA) in Mexican Americans, blacks, and non-Hispanic whites with diabetes in south Texas. METHODS: We summarized medical records for hospitalizations for LEAs for 1993 in six metropolitan statistical areas in south Texas. RESULTS: Age-adjusted incidence per 10,000 patients with diabetes was 146.59 in blacks, 60.68 in non-Hispanic whites, and 94.08 in Mexican Americans. Of the patients, 47% of amputees had a history of amputation, and 17.7% were hospitalized more than once during 1993. Mexican Americans had more diabetes-related amputations (85.9%) than blacks (74.7%) or non-Hispanic whites (56.3%). CONCLUSIONS: This study is the first to identify the incidence of diabetes-related lower-extremity amputations in minorities using primary data. Minorities had both a higher incidence and proportion of diabetes-related, LEAs compared with non-Hispanic whites. Public health initiatives and national strategies, such as Healthy People 2000 and 2010, need to specifically focus on high-risk populations and high-risk geographic areas to decrease the frequency of amputation and reamputation.

Black or African American↗
PubMed1999

Lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot.

BACKGROUND: The purpose of this study was to determine the degree to which pressure on the plantar aspect of the forefoot is reduced following percutaneous lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot. METHODS: Ten diabetic patients who had a history of neuropathic plantar ulceration of the forefoot were enrolled in a laboratory gait trial. A repeated-measures design and a computer analysis of force-plate data were used to examine dynamic pressures on the forefoot, with the patient walking barefoot, immediately before percutaneous lengthening of the Achilles tendon and at eight weeks afterward. Although the wound in each patient had healed at least one month before the operation, we considered the patients to be at high risk for ulceration because they had had an ulcer previously. RESULTS: The mean peak pressure (and standard deviation) on the plantar aspect of the forefoot decreased significantly from 86+/-9.4 newtons per square centimeter preoperatively to 63+/-13.2 newtons per square centimeter at eight weeks postoperatively (p<0.001). Commensurately, the mean dorsiflexion of the ankle joint increased significantly from 0+/-3.1 degrees preoperatively to 9+/-2.3 degrees at eight weeks post-operatively (p<0.001). CONCLUSIONS: The results of this study suggest that peak pressures on the plantar aspect of the forefoot are significantly reduced following percutaneous lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot. We are unaware of any other reports in the medical literature that describe such findings. These data may lend support to studies that have indicated that this procedure should be used as an adjunctive therapeutic or prophylactic measure to reduce the risk of neuropathic ulceration.

Achilles Tendon↗
PubMed1999

Factors associated with bone regrowth following diabetes-related partial amputation of the foot.

BACKGROUND: The formation of hypertrophic bone after partial resection of metatarsal bone has the potential to cause abnormal foci of high pressure in people who have diabetes mellitus; this may increase the risk of reulceration and reamputation. However, we are not aware of previous studies evaluating the risk factors for this entity. METHODS: The records of ninety-two adults (mean age, 54+/-10.1 years; range, thirty to seventy-four years) with diabetes who had had an isolated partial amputation of a ray were abstracted. Repeat radiographs were made for all of these subjects at a mean of 22+/-6.1 months (range, thirteen to thirty-five months) after the initial procedure. The formation of hypertrophic bone was defined as more than three millimeters of regrowth. RESULTS: A total of forty-one (45 percent) of the subjects had formation of hypertrophic bone at the time of radiographic analysis after isolated partial amputation of a ray. On multivariate analysis, the factors that were significantly associated with this regrowth of bone were male gender (88 percent [thirty-six] of the forty-one patients who had bone regrowth were male compared with 51 percent [twenty-six] of the fifty-one patients who did not have bone regrowth; p<0.01, odds ratio = 5.7, 95 percent confidence interval = 1.8 to 18.9), the use of manual bone-cutting instruments (used in 56 percent [twenty-three] of the forty-one patients who had bone regrowth compared with 16 percent [eight] of the fifty-one who did not; p<0.01, odds ratio = 4.7, 95 percent confidence interval = 1.6 to 13.8), and a resection made distal to the surgical neck of the metatarsal (used in 34 percent [fourteen] of the forty-one patients who had bone regrowth compared with 12 percent [six] of the fifty-one who did not; p<0.03, odds ratio = 4.5, 95 percent confidence interval = 1.2 to 16.9). The patients who had regrowth of bone were approximately eight times more likely to have reulceration at the site of the amputation than were those who did not have regrowth (24 percent [ten] of the patients with regrowth had reulceration compared with 4 percent [two] of the patients without regrowth; p<0.01, chi square = 8.4, odds ratio = 7.9, 95 percent confidence interval = 1.6 to 38.5). CONCLUSIONS: Overgrowth of the bone of a transected metatarsal predisposes patients to ulceration. Male gender, the use of manual bone-cutting instruments, and metaphyseal amputation may be associated with long-term regrowth of bone following isolated partial amputation of a ray. The use of power instruments during these procedures may lead to a lower prevalence of this reaction, thereby potentially reducing the risk of ulceration, infection, and reamputation.

Adult↗
PubMed1999

Total contact casts and removable cast walkers. Mitigation of plantar heel pressure.

The purpose of this study was to compare the ability of various modalities to reduce pressure in the plantar heel. Twenty-five patients with grade 1A plantar foot ulcerations were evaluated; a repeat measures design comparing plantar pressure was used to evaluate the total contact cast, the Aircast pneumatic walker, the DH pressure relief walker, and depth-inlay shoes. The total contact cast reduced pressure significantly better than the other modalities; however, its pressure reduction was only 33% less than a baseline sneaker. All other modalities reduced significantly more pressure than the depth-inlay shoe. The DH walker had a significantly lower pressure-time integral than other modalities. These data indicate that, while the total contact cast appears to be effective compared with other modalities, the role that limitation of transverse motion of the fat pad on compression at heel strike has yet to be fully explained.

Casts, Surgical↗
PubMed1999

Limb salvage with Chopart's amputation and tendon balancing.

For several decades, Chopart's amputation has met with some skepticism owing to reports of significant equinus deformity developing soon after the procedure is performed. However, with appropriate tendon balancing, which generally includes anterior tibial tendon transfer and tendo Achillis lengthening, this level of amputation is often more functional than slightly more distal amputations, such as Lisfranc or short transmetatarsal amputations. The authors offer a rationale for this observation, which includes a discussion of the longitudinal and transverse arch concept of the foot. This concept dictates that the shorter the midfoot-level amputation, the more likely the patient is to develop an equinovarus deformity, thus exposing the fifth metatarsal base and cuboid to weightbearing stress and a high risk of ulceration. Chopart's amputation, in eliminating the cuboid, often obviates the potential varus deformity and thus can have a more acceptable long-term result.

Achilles Tendon↗
PubMed1999

The increased prevalence of severe necrotizing infections caused by non-group A streptococci.

The authors report on 20 patients who were admitted to the University of Texas Health Science Center at San Antonio during a recent 4-month period with foot infections caused predominantly by non-group A streptococci. This number of patients was significantly greater than the number admitted to the same institution with the same diagnosis during the preceding 3 years. All patients had type 2 diabetes mellitus. In each case, a rapidly spreading cellulitis followed trauma to the foot, which necessitated emergent incision and drainage. Five patients required extensive fascial and skin debridement because of soft-tissue destruction, and two patients needed below-the-knee amputation because of uncontrolled infection. These cases suggest that non-group A streptococci, like group A streptococci, can cause serious skin and soft-tissue infections in patients with diabetes that may require aggressive surgical debridement despite appropriate antibiotic therapy.

Cellulitis↗
PubMed1999

Molecular mechanisms regulating follicular recruitment and selection.

Ovarian follicular growth and development is an integrated process encompassing both extraovarian signals, such as gonadotrophins and metabolic hormones, and intraovarian factors. Follicular development has been classified into gonadotrophin-independent and -dependent phases. In the latter, FSH provides the primary drive for follicular recruitment and LH is required for continued development of follicles to the preovulatory stage. A transient increase in circulating FSH precedes the recruitment of a group of follicles, and these recruited follicles are characterized by expression of mRNAs encoding P450scc and P450arom in granulosal cells. As follicles mature, there is a transfer of dependency from FSH to LH, which may be part of the mechanism(s) involved in selection of follicles for continued growth. Indeed, changes in the pattern of expression of mRNA for gonadotrophin receptors and steroid enzymes within follicular cells appear to be closely linked to changes in peripheral concentrations of gonadotrophins. The mechanism of selection of dominant follicles still requires clarification, but seems to be linked to the timing of mRNA expression encoding LHr and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) in granulosal cells. Additional intraovarian systems, including the ovarian IGF and activin/inhibin systems, also exert a role. For example, it appears that the development of follicular dominance in cows is associated with the FSH-dependent inhibition of the expression of mRNA encoding insulin-like growth factor binding protein 2 (IGFBP-2) in granulosal cells. In conclusion, the integration of these endocrine signals and intraovarian factors within follicles determines whether follicles continue to develop and become dominant or are diverted into apoptotic pathways leading to atresia.

3-Hydroxysteroid Dehydrogenases↗
PubMed1998

Diabetic foot ulcers: prevention, diagnosis and classification.

Diabetic ulcers are the most common foot injuries leading to lower extremity amputation. Family physicians have a pivotal role in the prevention or early diagnosis of diabetic foot complications. Management of the diabetic foot requires a thorough knowledge of the major risk factors for amputation, frequent routine evaluation and meticulous preventive maintenance. The most common risk factors for ulcer formation include diabetic neuropathy, structural foot deformity and peripheral arterial occlusive disease. A careful physical examination, buttressed by monofilament testing for neuropathy and noninvasive testing for arterial insufficiency, can identify patients at risk for foot ulcers and appropriately classify patients who already have ulcers or other diabetic foot complications. Patient education regarding foot hygiene, nail care and proper footwear is crucial to reducing the risk of an injury that can lead to ulcer formation. Adherence to a systematic regimen of diagnosis and classification can improve communication between family physicians and diabetes subspecialists and facilitate appropriate treatment of complications. This team approach may ultimately lead to a reduction in lower extremity amputations related to diabetes.

Amputation, Surgical↗
PubMed1998

Choosing a practical screening instrument to identify patients at risk for diabetic foot ulceration.

OBJECTIVE: To evaluate the sensitivity and specificity of 3 sensory perception testing instruments to screen for risk of diabetic foot ulceration. METHODS: This case-control study prospectively measured the degree of peripheral sensory neuropathy in diabetic patients with and without foot ulcers. We enrolled 115 age-matched diabetic patients (40% male) with a case-control ratio of approximately 1:3 (30 cases and 85 controls) from a tertiary care diabetic foot specialty clinic. Cases were defined as individuals who had an existing foot ulceration or a history of a recently (< 4 weeks) healed foot ulceration. Controls were defined as subjects with no foot ulceration history. Using receiver operating characteristic analysis, we evaluated the sensitivity and specificity of 2 commonly used nephropathy assessment tools (vibration perception threshold testing and the Semmes-Weinstein 10-g monofilament wire system) and a 4-question verbal neuropathy score to evaluate for presence of foot ulceration. RESULTS: A vibration perception threshold testing using 25 V and lack of perception at 4 or more sites using the Semmes-Weinstein 10-g monofilament wire system had a significantly higher specificity than neuropathy score used. The neuropathy score was most sensitive when 1 or more answers were affirmative. When modalities were combined, particularly the monofilament wire system plus vibration perception threshold testing and the neuropathy score plus the monofilament wire system, there was a substantial increase in specificity with little or no diminution in sensitivity. CONCLUSIONS: The early detection of peripheral neuropathy or loss of "protective sensation" is paramount to instituting a structured treatment plan to prevent lower extremity amputation. The results of our study suggest that all 3 sensory perception testing instruments are sensitive in identifying patients at risk for ulceration. Combining modalities appears to increase specificity with very little or no diminution in sensitivity.

Adult↗
PubMed1998

Practical criteria for screening patients at high risk for diabetic foot ulceration.

BACKGROUND: A comprehensive understanding of clinical risk factors for developing foot ulcerations would help clinicians to categorize patients by their risk status and schedule intervention resources accordingly to prevent amputation. OBJECTIVE: To evaluate risk factors for foot ulcerations among persons with diabetes mellitus. METHOD: We enrolled 225 age-matched patients, 46.7% male, with a ratio of approximately 1:2 cases: controls (76 case-patients and 149 control subjects). Case-patients were defined as subjects who met the enrollment criteria and who had an existing foot ulceration or a recent history of a foot ulceration. Control subjects were defined as subjects with no history of foot ulceration. A stepwise logistic regression model was used for analysis. RESULTS: An elevated plantar pressure (> 65 N/cm2), history of amputation, lengthy duration of diabetes (> 10 years), foot deformities (hallux rigidus or hammer toes), male sex, poor diabetes control (glycosylated hemoglobin > 9%), 1 or more subjective symptoms of neuropathy, and an elevated vibration perception threshold (> 25 V) were significantly associated with foot ulceration. In addition, 59 patients (78%) with ulceration had a rigid deformity directly associated with the site of ulceration. No significant associations were noted between vascular disease, level of formal education, nephropathy, retinopathy, impaired vision, or obesity and foot ulceration on multivariate analysis. CONCLUSIONS: Neuropathy, foot deformity, high plantar pressures, and a history of amputation are significantly associated with the presence of foot ulceration. Although vascular and renal disease may result in delayed wound healing and subsequent amputation, they are not significant risk factors for the development of diabetic foot ulceration.

Adult↗
PubMed1998

Risk factors for diabetic foot ulceration: a logical approach to treatment.

Appropriate management of the diabetic foot in a multidisciplinary setting requires knowledge of the risk factors leading to ulceration and limb loss. This article will review the most common risk factors for ulceration and present a validated, treatment-based method to appropriately communicate both the status of the diabetic wound and, more important, the patient's location on a spectrum of risk for amputation.

Diabetic Foot↗
PubMed1998

Acute Charcot's arthropathy of the foot and ankle.

With the possible exception of osteomyelitis, Charcot's arthropathy is perhaps the most debilitating orthopedic sequela of diabetes mellitus. For this reason, early diagnosis and aggressive, noncompromising immobilization, pressure reduction, and consistent follow-through are paramount to effecting an acceptable result.

Algorithms↗
PubMed1998

Expression of monocyte chemoattractant protein-1 in the bovine corpus luteum around the time of natural luteolysis.

Monocyte chemoattractant protein (MCP-1) is a specific chemoattractant for monocytes/macrophages that could have a role in the influx of macrophages into the corpus luteum (CL) during structural luteolysis. In this study, reverse transcription-polymerase chain reaction and in situ hybridization were used to investigate MCP-1 mRNA expression in CL collected from 18 heifers between Days 15 and 20 of the estrous cycle. There was expression of mRNA encoding MCP-1 in luteal tissue from all cows; however, expression was greater in animals that had undergone luteolysis at the time of CL collection as compared to animals in which the CL was still functional. Similarly, in situ hybridization showed greater expression of mRNA encoding MCP-1 in CL after functional luteolysis. There was also evidence of increased MCP-1 mRNA expression in an animal with a functional CL where the systemic concentration of prostaglandin F2alpha metabolite was high at the time of tissue collection. T lymphocyte populations, identified by immunohistochemistry, had a distribution similar to that of cells expressing MCP-1 mRNA within the CL, but other cell types were also involved. These results demonstrate an increase in MCP-1 mRNA after functional luteolysis in the cow, which may be related to the influx of macrophages that occurs at this time.

Animals↗