Biomedical subjects

Brian D Adams

Publications and source records attributed to Brian D Adams.

15 recordsLinked to original sources

PubMed2006

Stratum-specific expression of human transferrin receptor increases iron in mouse epidermis.

Epidermal desquamation accounts for 20% of the body's iron loss each day. Yet, little is known about how iron content in epidermis is regulated. To test the importance of the transferrin receptor in regulating iron content in epidermis, we created transgenic mice that have stratum-specific expression of the human transferrin receptor. The keratin 14 promoter targeted the receptor primarily to basal, proliferating keratinocytes; the involucrin (Inv) promoter targeted the receptor to suprabasal, differentiating keratinocytes. There were age- and site-dependent differences in iron content in the epidermis and hair. In both types of transgenic mice, epidermal iron content increased with age and at 8 weeks was 2-3-fold greater in transgenic mice compared to littermate controls. Iron was increased up to 2-fold in hair of keratin 14-human transferrin receptor (hTfR) transgenics and 30% in Inv-hTfR transgenics. No gross or histological changes were seen in transgenic animals with increased iron in the epidermis. Ferritin expression, which was low in normal epidermis, was greatly increased in both transgenic lines, indicating that it is the likely depot for the extra iron in these animals. These data show that control of transferrin receptor expression is sufficient to regulate iron content in proliferating or differentiating keratinocytes in the epidermis.

Animals↗

PubMed2005

Total wrist arthroplasty.

Total wrist arthroplasty preserves motion and improves hand function for daily tasks and lower-demand vocational and a vocational activities. It is often preferable to fusion when both wrists are arthritic. Newer prosthetic designs provide a functional range of motion, better wrist balance,reduced risk of loosening, and better implant stability than older designs. The success of total wrist arthroplasty depends on appropriate patient selection, careful preoperative planning, and sound surgical technique.

Arthroplasty, Replacement↗

PubMed2005

Iron in skin of mice with three etiologies of systemic iron overload.

In human hemochromatosis, tissue toxicity is a function of tissue iron levels. Despite reports of skin toxicity in hemochromatosis, little is known about iron levels in skin of individuals with systemic iron overload. We measured skin iron and studied skin histology in three mouse models of systemic iron overload: mice with a deletion of the hemochromatosis (Hfe) gene, mice fed a high iron diet, and mice given parenteral injections of iron. In Hfe(-/-) mice, iron content in the epidermis and dermis was unexpectedly the same as in Hfe(+/+) mice, and there were no histological abnormalities detected after 30 wk. A high iron diet produced increased iron in the epidermis of both normal and Hfe(-/-) animals; a high diet increased iron in the dermis only in Hfe(-/-) mice. Increased skin iron was not associated with other histological changes, even after 19 wk. Parenteral administration of iron produced increased iron in the epidermis and dermis, and gave the skin a bronze hue. These results show that the amount and distribution of iron in the skin depends on the etiology of iron overload. It appears that neither Hfe deletion nor elevated skin iron alone can account for cutaneous manifestations reportedly seen in humans with hereditary hemochromatosis.

Animals↗

PubMed2004

Total wrist arthroplasty.

Normal wrist motion is accomplished by a complex interaction of multiple articulations involving the radius, ulna, and carpal bones. Total wrist arthroplasty cannot duplicate this intricate system, but it can potentially produce a stable, pain-free joint with functional range of motion. Achieving a functional and durable outcome requires proper patient selection, careful preoperative planning, and accurate implantation. Because arthroplasty poses greater risks than arthrodesis, low demand patients with special needs or desires for wrist motion are the best candidates. In particular, patients with arthritis involving multiple joints of the upper limbs often find tasks of daily living easier when some wrist motion is preserved. Other patients may choose arthroplasty over arthrodesis to better maintain their ability to perform vocational and avocational activities. Regardless of a patient's desire for arthroplasty, he or she must accept the lifetime of restricted activities imposed by an artificial wrist, which are similar to any other joint replacement. Complications may include infection, imbalance, implant breakage, dislocation, and loosening. Revision arthroplasty or conversion to an arthrodesis are options for the failed total wrist.

Journal Article↗

PubMed2004

Total wrist arthroplasty.

With the advent of newer prosthetic designs, total wrist arthroplasty provides a functional range of motion, better wrist balance, reduced risk of loosening, and better implant stability.

Arthrodesis↗

PubMed2004

Surgical management of the arthritic wrist.

Wrist destruction by rheumatoid arthritis adversely affects hand function and increases the risk of finger deformities. Surgical management is indicated not only for salvage of end-stage wrist deformity but to alleviate pain and reduce progression of deformity at earlier stages. Available procedures include arthroscopic synovectomy, partial and complete arthrodesis, and implant arthroplasty. Procedure selection is highly dependent on disease characteristics and patient needs.

Arthritis, Rheumatoid↗

PubMed2003

Comparison of arthroplasty and arthrodesis for the rheumatoid wrist.

PURPOSE: To compare the outcomes of wrist arthrodesis and arthroplasty in the treatment of rheumatoid arthritis using validated outcome patient surveys and a review of surgical complications in 2 matched cohorts. METHODS: Forty-six patients with 51 operated wrists (24 arthrodeses and 27 arthroplasties) were reviewed retrospectively at a follow-up range of 1 to 5 years. Patients completed the Disabilities of the Arm, Shoulder and Hand (DASH) inventory, the Patient-Rated Wrist Evaluation (PRWE), and a questionnaire designed specifically for this study. Surgical complications were obtained by chart review. RESULTS: Treatment groups were well matched by patient characteristics and radiographic staging. There were no statistical differences in the survey scores between the 2 groups. Patients in the arthroplasty group, however, reported a trend toward greater ease with personal hygiene and fastening buttons. Complication rates were similar with a 56% complication rate in the arthrodesis group (22% major, 35% minor) and a 52% complication rate in the arthroplasty group (11% major, 41% minor). CONCLUSIONS: The DASH and PRWE may not be designed properly to measure impairment caused by wrist disease in patients with generalized arthritis. The results show that patients with rheumatoid arthritis can and do accommodate to a wrist arthrodesis. It should not be construed, however, that patients with rheumatoid arthritis would not prefer or obtain greater benefit from a wrist arthroplasty [corrected].

Arthritis, Rheumatoid↗

PubMed2003

Impact of impaired wrist motion on hand and upper-extremity performance(1).

PURPOSE: To quantify and compare the disabilities caused by reduced and absent wrist motion using objective measurements of task performance and perceived disability, and to assess the compensatory motions of the shoulder, elbow, forearm, and trunk caused by impaired wrist motion. METHODS: A clinical study of 21 normal subjects was done to measure physical performance and to assess wrist function under conditions of reduced (30 degrees flexion and 30 degrees extension) and nearly absent wrist motion using established physical tests and questionnaires (Disabilities of the Arm, Shoulder, and Hand [DASH], Patient Rated Wrist Evaluation [PRWE], and a study-specific survey). The clinical study also measured compensatory motions of the shoulder, elbow, forearm, and trunk. RESULTS: Average times to perform the Jebsen test and activities of daily living (ADLs) test increased for both motion-restricted conditions of the wrist but did not differ significantly between the conditions. Questionnaire scores regarding function were significantly worse for both motion-restricted conditions and poorest for nearly absent motion. Average compensatory motions in the extremity and trunk statistically increased for both motion-restricted conditions but were not marked and did not differ between the conditions. High variability among subjects occurred in all physical tests and questionnaires for both motion-restricted conditions. CONCLUSIONS: Perceived disability from reduced wrist motion appeared greater than measured functional loss using common physical tests and outcome surveys.

Activities of Daily Living↗

PubMed2003

Antimicrobial management of mutilating hand injuries.

Antimicrobial drugs are commonly used in the treatment of mutilating hand injuries. Valid arguments for the use of systemic antibiotics can be made despite the lack of data clearly documenting their efficacy in this clinical scenario. There is no information to support the use of topical agents in open hand injuries. When choosing an appropriate systemic antibiotic, the physician should consider unique characteristics of these injuries, the various environments in which they occur, and the potential infecting organisms. The duration of antibiotic use is arbitrary but should be minimized to avoid complications and the development of bacterial resistance.

Accidents, Occupational↗

PubMed2002

An analysis of bone stresses and fixation stability using a finite element model of simulated distal radius fractures.

A 3-dimensional finite element model was used to study pin fixation in simulated unstable extra-articular distal radius fractures. Bone geometry and material properties were generated from computed tomography. The model was validated in cadaver testing. The model is robust and an accurate predictor of bone stresses and fracture stability under pure axial load. Three different pinning configurations and 3 different pin materials were evaluated. Crossed pinning provided greater fracture stability and a broader distribution of bone stresses than pinning through the radius styloid alone. Steel pins provided greater fracture stability; however, bioabsorbable pins produced lower stress concentration in the bone near the pins. A finite element model is useful in showing differences between various pin constructs in the treatment of distal radius fractures.

Aged↗

PubMed2002

Long-term outcome of nonsurgically treated patients with wrist pain and a normal arthrogram.

A series of 52 patients who had been treated nonsurgically for wrist pain after an inconclusive physical examination, normal standard radiographs, and a negative radiocarpal arthrogram result were surveyed using the Disabilities of the Arm, Shoulder, and Hand (DASH) and Short Form-12 (SF-12) instruments after a minimum of 2 years (average, 6.1 years). Forty-two patients (81%) responded to the survey. Average duration of symptoms before the initial evaluation was 13 months. At follow-up evaluation, mean SF-12 score was 50 (national mean, 50). Mean DASH score was 17 compared with 2 for a control group of 60 people. Sixty-four percent of patients reported improvement, 19% were unchanged, and 17% were worse since the initial evaluation. Two patients were receiving disability benefits. Duration of symptoms >12 months was associated with a worse outcome. These results show that patients with wrist pain but without a diagnosis by these evaluation methods often have persistent symptoms after nonsurgical treatment, but the symptoms are usually mild and improve.

Adult↗

PubMed2002

Early results of the Universal total wrist arthroplasty in rheumatoid arthritis.

Early results of 2 surgeons involved in a prospective study of the Universal total wrist prosthesis (KMI, San Diego, CA) are reported. Twenty-two prostheses were implanted in 19 patients for the treatment of severe rheumatoid arthritis. Two-year follow-up results of 8 wrists and 1-year follow-up results of 14 wrists were reviewed. Total arcs of motion (flexion-extension, radial-ulnar deviation, and pronation-supination) all improved significantly after arthroplasty. Individual motions that were most limited before surgery (extension, radial deviation, and supination) improved the most. Disabilities of the Arm, Shoulder, and Hand outcome scores improved 14 points at 1 year and 24 points at 2 years. Three prostheses (14%) were unstable and required further treatment; all 3 were in patients with highly active disease and severe wrist laxity. The Universal prosthesis provides a good early outcome in rheumatoid patients without severe preoperative wrist laxity.

Adult↗

PubMed2002

An anatomic reconstruction of the distal radioulnar ligaments for posttraumatic distal radioulnar joint instability.

Fourteen patients with posttraumatic distal radioulnar joint instability were treated with a reconstruction of the distal radioulnar ligaments. The technique is anatomically accurate, is reproducible, and requires less dissection than previously described techniques. Candidates for the procedure had joint instability and an irreparable triangular fibrocartilage complex. Ten patients had bidirectional instability. Two patients had a concurrent corrective osteotomy of the distal radius for a malunion. The procedure restored stability and relieved symptoms in 12 of 14 patients at 1 to 4 years' follow-up evaluation. One patient with a deficient sigmoid notch and one with ulnocarpal ligament injury did not achieve full stability. All patients attained near full pronation and supination. The procedure is an effective treatment for an unstable distal radioulnar joint when its articular surfaces are intact and the other wrist ligaments are functional, and it can be used in combination with a distal radius corrective osteotomy.

Adolescent↗

PubMed2002

Androgen receptors in human synoviocytes and androgen regulation of interleukin 1beta (IL-1beta) induced IL-6 production: a link between hypoandrogenicity and rheumatoid arthritis?

OBJECTIVE: To investigate the hypothesis that synoviocytes possess androgen receptors (AR) that could be modulated by the non-aromatizable androgen, dihydrotestosterone (DHT), resulting in altered levels of inflammatory cytokines. METHODS: Using molecular analyses of AR in combination with the multiprobe ribonuclease protection assay and ELISA, we investigated the presence of AR and the effect of DHT on interleukin 1beta (IL-1beta) induced expression of the IL-6 superfamily of cytokines in synoviocytes. RESULTS: Our studies corroborate the presence of AR in synoviocytes. DHT exerts a suppressive effect on IL-1beta induced IL-6, macrophage-colony stimulating factor (CSF), and granulocyte-CSF production by synoviocytes. This modulatory effect is exerted at both the transcriptional and translational level; 17beta-estradiol, at high concentrations, had a stimulatory effect. CONCLUSION: The identification of functional AR in synoviocytes and the modulatory effect of DHT on the inflammatory process in the joint suggest a direct link between hypoandrogenicity and rheumatoid arthritis (RA) disease status. Understanding the complex regulation of inflammatory cytokines by hormones may contribute to the development of new therapeutic targets for clinical intervention in RA.

Adolescent↗

PubMedDate not supplied

Impact of simulated proximal interphalangeal arthrodeses of all fingers on hand function.

PURPOSE: To evaluate the impact of simulated proximal interphalangeal (PIP) arthrodeses on hand performance and to assess the resulting compensatory metacarpophalangeal (MCP) joint motions in healthy subjects. METHODS: Fifteen healthy subjects were tested under 2 conditions: (1) with unrestricted distal interphalangeal, PIP, and MCP joints and (2) with the PIP joint fixed at 40 degrees of flexion in all 4 fingers of 1 hand and unrestricted MCP and distal interphalangeal joints. Subjects performed the Jebsen hand function test and 13 activities of daily living. Perceived difficulty in performing tasks was assessed with a study-specific questionnaire. The motion of each finger was monitored using a motion analysis system. RESULTS: The average time to complete the Jebsen test did not increase significantly with simulated PIP arthrodesis, nor did subjects perceive the tasks to be more difficult. Activities of daily living tasks requiring power grasp did not show significant increases in MCP flexion or abduction. Precision handling tasks requiring greater PIP joint flexion did show increased MCP flexion and were associated with greater perceived difficulty. CONCLUSIONS: Our study showed a minimal overall impact from simulated arthrodeses of all 4 fingers at the PIP joints in 40 degrees of flexion when measured by selected lower-demand activities of daily living in healthy subjects. Precision handling tasks that normally use higher degrees of PIP joint flexion, however, were perceived to be more difficult to perform and required greater compensatory motion at the MCP joints. This study does not address directly the impairment that patients with generalized hand arthritis may experience after PIP joint arthrodesis. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic, Level I.

Activities of Daily Living↗