Myofascial trigger point (MTrP) size and elasticity properties can be used to differentiate characteristics of MTrPs in lower back skeletal muscle.

Myofascial trigger points (MTrPs) are localized contraction knots that develop after muscle overuse or an acute trauma. Significant work has been done to understand, diagnose, and treat MTrPs in order to improve patients suffering from their effects. However, effective non-invasive diagnostic tools are still a missing gap in both understanding and treating MTrPs. Effective treatments for patients suffering from MTrP mediated pain require a means to measure MTrP properties quantitatively and diagnostically both prior to and during intervention. Further, quantitative measurements of MTrPs are often limited by the availability of equipment and training. Here we develop ultrasound (US) based diagnostic metrics that can be used to distinguish the biophysical properties of MTrPs, and show how those metrics can be used by clinicians during patient diagnosis and treatment. We highlight the advantages and limitations of previous US-based approaches that utilize elasticity theory. To overcome these previous limitations, we use a hierarchical approach to distinguish MTrP properties by patients' reported pain and clinician measured palpation. We show how US-based measurements can characterize MTrPs with this approach. We demonstrate that MTrPs tend to be smaller, stiffer, and deeper in the muscle tissue for patients with pain compared to patients without pain. We provide evidence that more than one MTrP within a single US-image field increases the stiffness of neighboring MTrPs. Finally, we highlight a combination of metrics (depth, thickness, and stiffness) that can be used by clinicians to evaluate individual MTrPs in combination with standard clinical assessments.

Whole-body vibration influences lower extremity circulatory and neurological function.

Whole-body vibration (WBV) is currently used to enhance performance and treat injuries even though we lack an understanding of how WBV influences physiological processes. An improved understanding of the physiological effects of WBV could lead to protocols to speed healing or treat pathologies. This study examined the acute effects of WBV on peripheral blood perfusion, muscle oxygenation, motoneuron pool excitability, and sensory nerve conduction velocity. Fourteen healthy participants [9 women (21.7 ± 2.4 years); 5 men (20.8 ± 1.1 years)] completed a 5 min bout of WBV (50 Hz, 2 mm amplitude). Measures were assessed pre-treatment and at 0, 5, 10, 15, and 20 min post-treatment. WBV significantly increased superficial skin temperature (P < 0.0005) and total hemoglobin (P = 0.009), had no effect of oxyhemoglobin (P = 0.186), increased deoxyhemoglobin (P < 0.0005), inhibited the soleus Hoffmann reflex (P = 0.007), and had no effect on sural sensory nerve conduction velocity (P = 0.695). These results suggest that an acute bout of WBV influences physiological processes in both the circulatory and the nervous systems.

Modulation of soleus H-reflex by presynaptic spinal mechanisms during varying surface and ankle brace conditions.

AIMS: Reflex excitability is modulated in part by presynaptic spinal mechanisms. Presynaptic inhibition may prevent an over-response of the motoneuron pool to afferent information. A paired-reflex depression (PRD) conditioning protocol can be used to monitor reflex plasticity. Manipulation of stance, surface, and external bracing are common methods of rehabilitating and treating lower extremity musculoskeletal injuries. The intent of this study was to evaluate changes in PRD of the soleus H-reflex during single-leg stance under varying stability conditions. METHODS: Seven trials were completed for each condition in ten healthy volunteers (age=23+/-1.8 yr, weight 65.0+/-11.3 kg, height=168.7+/-28.0 cm). The conditioning stimuli were composed of soleus H-reflex pairs evoked 80 ms apart at an equal intensity. The mean percent decrease of the second H-reflex relative to the first represented PRD. RESULTS: A 2 x 2 repeated measures ANOVA (P<0.05) was used to evaluate influence of surface (foam, no foam) and support (semi-rigid ankle brace, no ankle brace) on PRD. Main effects testing revealed a significantly greater soleus PRD (P=.034) for the foam surface (62.5%) compared the flat surface (57.5%). Ankle brace application did not influence soleus PRD (P=0.63). CONCLUSION: The increase in soleus PRD during the foam condition suggests depression of the motoneuron pool. This may lessen postural over-corrections while maintaining upright stance during less stable conditions. No change in PRD during the ankle brace condition suggests that mechanical reinforcement provided an increase in ankle stability, decreasing the demand on the motoneuron pool.

Effect of inversion and ankle bracing on peroneus longus Hoffmann reflex.

This study examined peroneus longus (PL) Hoffmann reflex (H-reflex) during sudden inversion perturbation of the ankle/foot complex under an ankle brace and non-brace condition. Ten healthy subjects volunteered. H-reflexes were tested on the up-sloping portion of the recruitment curve, utilizing a control trial M-wave above motor threshold to maintain consistency between subjects and conditions. The PL H/maximum M-wave (M(max)) ratio was established using the PL H-reflex and PL M(max) peak-to-peak measures. The mean ratio across five trials for each subject under each ankle brace (brace, no brace) and surface (flat, inversion) conditions was utilized for analysis. The 1 x 4 repeated measures ANOVA revealed a significant main effect for treatment condition (P<0.0001). The PL H/M(max) ratio significantly increased during sudden inversion-no ankle brace condition compared with the flat surface no-ankle brace condition (P=0.04). Application of an ankle brace had no effect on PL H/M(max) ratio during inversion (P=0.78). During this study PL H/M(max) ratios increased during an inversion perturbation in healthy ankles. This is believed to occur due to heightened sensorimotor demand placed on the nervous system during this motion. Moreover, application of an ankle brace during inversion does not appear to affect PL H/M(max) ratio.

Histological effects of tazarotene 0.1% cream vs. vehicle on photodamaged skin: a 6-month, multicentre, double-blind, randomized, vehicle-controlled study in patients with photodamaged facial skin.

BACKGROUND: Topical tazarotene has been shown to offer efficacy in ameliorating multiple effects of photodamage. OBJECTIVES: To evaluate the histological effects of tazarotene cream on photodamaged skin. METHODS: In this multicentre, double-blind, randomized, vehicle-controlled study, 50 patients with photodamaged facial skin (at least mild fine wrinkling and mottled hyperpigmentation, with at least one of these being moderate) were randomized to apply tazarotene 0.1% cream or vehicle cream to their face, once daily for 24 weeks. RESULTS: Blinded assessments showed that tazarotene was less likely than vehicle to be associated with an increase in keratinocytic and melanocytic atypia, and more likely than vehicle to be associated with a reduction in atypia. Between-group comparisons in distribution of change from baseline categories of severity were in favour of tazarotene (P = 0.055 for keratinocytic atypia, P = 0.034 for melanocytic atypia, and P < 0.001 for the number of granular cell layers). Compared with vehicle, tazarotene was associated with an increase in epidermal polarity (P = 0.008) and epidermal thickness (P = 0.012), and a tendency for stratum corneum compaction. Tazarotene was also associated with widened intercellular spaces (reported as epidermal oedema) relative to vehicle (P < 0.001). CONCLUSIONS: Treatment of photodamaged skin with tazarotene is associated with an amelioration of keratinocytic and melanocytic atypia, an improvement in epidermal polarity, and an increase in epidermal thickness.

Tazarotene cream for the treatment of facial photodamage: a multicenter, investigator-masked, randomized, vehicle-controlled, parallel comparison of 0.01%, 0.025%, 0.05%, and 0.1% tazarotene creams with 0.05% tretinoin emollient cream applied once daily for 24 weeks.

OBJECTIVE: To assess the safety and efficacy of 4 concentrations of tazarotene cream in the treatment of facial photodamage. DESIGN: Prospective weekly multicenter, investigator-masked, randomized, parallel-group study. SETTING: University hospitals and clinical research centers. PATIENTS: Three hundred forty-nine subjects with facial photodamage. INTERVENTION: Daily topical application of tazarotene cream (0.01%, 0.025%, 0.05%, and 0.1%) compared with its vehicle and with 0.05% tretinoin emollient cream. RESULTS: Tazarotene cream and tretinoin cream significantly improved mottled hyperpigmentation and fine wrinkles. At week 24, treatment success rates based on global responses were 67% (39 of 58 subjects) with 0.1% tazarotene, 52% (30 of 58 subjects) with 0.05% tazarotene, 36% (21 of 58 subjects) with 0.025% tazarotene, 41% (24 of 59 subjects) with 0.01% tazarotene, 55% (32 of 58 subjects) with 0.05% tretinoin, and 22% (13 of 58 subjects) with vehicle. Local adverse events, although more frequent with tazarotene at higher concentrations, were generally mild to moderate. CONCLUSIONS: Tazarotene in a cream formulation is safe and is associated with positive changes in the treatment of photodamaged facial skin.

A pilot study to determine the effect of tazarotene gel 0.1% on steroid-induced epidermal atrophy.

BACKGROUND: Repeated applications of a corticosteroid can induce epidermal atrophy. This study was performed to investigate whether the adjunctive use of tazarotene gel 0.1% might help to minimize the development of steroid-induced epidermal atrophy. METHODS: Each of 24 healthy volunteers received the following six treatments (applied 6 days per week for 4 weeks), which were randomized to each of six sites on their forearms: no treatment, tazarotene vehicle, tazarotene vehicle + tazarotene gel 0.1%, diflorasone diacetate 0.05% ointment, diflorasone diacetate 0.05% ointment + tazarotene vehicle, or diflorasone diacetate 0.05% ointment + tazarotene gel 0.1%. RESULTS: The mean epidermal thickness was increased by 20% (NS) and 62% (P < or = 0.0005) after applications of tazarotene vehicle and tazarotene gel 0.1%, respectively. Application of diflorasone diacetate reduced the mean epidermal thickness by 43% (P < or = 0.0005). Concomitant application of tazarotene gel 0.1% with diflorasone diacetate did not entirely prevent atrophy, but was shown to ameliorate 37% of the epidermal atrophy induced by diflorasone diacetate alone (P < or = 0.003 compared with steroid monotherapy). CONCLUSIONS: Tazarotene gel 0.1% significantly reduces epidermal atrophy induced by diflorasone diacetate 0.05% ointment.

Tazarotene plus UVB phototherapy in the treatment of psoriasis.

BACKGROUND: The addition of oral retinoids to phototherapy may accelerate and enhance antipsoriatic efficacy, but can result in systemic adverse events and additional laboratory monitoring costs. OBJECTIVE: Our purpose was to determine whether the topical addition of tazarotene to UVB phototherapy improves efficacy without problems related to photosensitivity. METHODS: Bilateral target plaques were randomized to receive two of the following, one on each plaque once daily for 14 days: tazarotene 0.1% gel, vehicle gel, or no treatment. Thereafter, the same treatments were continued 3 times per week, plus UVB phototherapy 3 times per week, for an additional 67 days. RESULTS: Tazarotene plus UVB phototherapy achieved faster and significantly greater reductions in plaque elevation and scaling throughout treatment and achieved at least 50% improvement from the pretreatment baseline with a significantly lower median cumulative UVB exposure than vehicle gel plus UVB light or UVB phototherapy alone. No case of unusual photosensitivity was noted in the tazarotene plus UVB treatment group. CONCLUSION: The addition of tazarotene to UVB phototherapy improves and accelerates efficacy and maintains acceptable safety and tolerability.

Photodamage pilot study: a double-blind, vehicle-controlled study to assess the efficacy and safety of tazarotene 0.1% gel.

BACKGROUND: Tazarotene, a potent acetylenic retinoid for topical use, might be expected to benefit photodamaged skin, including improving the classical signs of fine wrinkles, mottled hyperpigmentation, and roughness. OBJECTIVE: Our purpose was to determine the efficacy and safety of tazarotene 0.1% gel in the treatment of photodamaged dorsal forearm skin. METHODS: Ten healthy female volunteers, aged 45 to 65 years, with moderately photodamaged forearm skin applied tazarotene 0.1% gel to one arm and vehicle gel to the other once daily for 12 weeks. The study was a double-blind, randomized, paired-comparison evaluation conducted at a single site. RESULTS: Tazarotene showed beneficial effects for several efficacy variables. It was more efficacious than vehicle in reducing skin roughness and fine wrinkling based on objective measurements. Tazarotene also corrected epidermal atrophy and atypia and improved skin hydration properties. CONCLUSION: In this 12-week pilot study tazarotene redressed abnormalities associated with photo-damaged skin.

Tazarotene gel is safe and effective in the treatment of acne vulgaris: a multicenter, double-blind, vehicle-controlled study.

Retinoids reverse the abnormal pattern of keratinization seen in acne vulgaris. Tazarotene is the first of a novel family of topical receptor-selective acetylenic retinoids. This study evaluates the safety and efficacy of topical tazarotene 0.1% and 0.05% gels, in comparison to vehicle gel, applied once daily for 12 weeks, in the treatment of mild-to-moderate facial acne vulgaris. A total of 446 patients with facial acne vulgaris were enrolled, and 375 patients, ranging in age from 14 to 44 years, were evaluable in this multicenter, double-blind, randomized study. In comparison to vehicle gel, treatment with tazarotene 0.1% gel resulted in significantly greater reductions in noninflammatory and total lesion counts at all follow-up visits, and inflammatory lesion counts at Week 12. Tazarotene 0.05% gel resulted in significantly greater reductions in noninflammatory and total lesion counts than vehicle gel at Weeks 8 and 12. At Week 12, treatment success rates were 68% and 51% for tazarotene 0.1% and 0.05%, respectively (40% for vehicle gel). Tazarotene gel was an effective, safe, and generally well-tolerated therapy for the treatment of acne vulgaris.

Tazarotene 0.1% gel plus corticosteroid cream in the treatment of plaque psoriasis.

BACKGROUND: Topical corticosteroids are often used in the treatment of psoriasis, but long-term use may be associated with serious adverse events such as tachyphylaxis or atrophy of the skin. Tazarotene, a new topical retinoid, has demonstrated significant clinical benefits but can cause mild to moderate local irritation. OBJECTIVE: We evaluate whether a combination treatment of topical tazarotene and a topical corticosteroid would increase efficacy while reducing the incidence of local adverse events associated with a topical retinoid. METHODS: Three hundred patients enrolled in an investigator-masked study were randomly assigned to 1 of 4 treatment groups: tazarotene 0.1% gel in combination with placebo cream, or with a low-, mid-, or high-potency corticosteroid cream, for 12 weeks of treatment and a posttreatment follow-up at week 16. RESULTS: Tazarotene 0.1% gel in combination with a mid- or high-potency corticosteroid, when compared with tazarotene plus placebo cream, achieved significantly greater reductions in scaling, erythema, and overall lesional severity, and a decreased incidence of adverse events. CONCLUSION: All tazarotene combinations (including tazarotene plus placebo) were highly effective in rapidly reducing the severity of psoriasis. Combining tazarotene with a topical corticosteroid increased efficacy while reducing the incidence of local adverse events.

Once-daily tazarotene gel versus twice-daily fluocinonide cream in the treatment of plaque psoriasis.

BACKGROUND: A new class of topical receptor-selective acetylenic retinoids, the first of which is tazarotene, has been developed. OBJECTIVE: Our purpose was to compare the safety, efficacy, and duration of therapeutic effect of 12 weeks of once-daily tazarotene 0.1% and 0.05% gel with that of twice-daily fluocinonide 0.05% cream in the treatment of patients with plaque psoriasis. METHODS: Three hundred forty-eight patients with plaque psoriasis were enrolled and 275 patients completed a multicenter, investigator-masked, randomized, parallel-group clinical trial. RESULTS: Both tazarotene gels were as effective as fluocinonide in reducing plaque elevation after 1 week of treatment, and tazarotene 0.1% gel was similar to fluocinonide in reducing scaling of trunk/limb lesions at all study weeks except week 4. Tazarotene 0. 1% gel was similar to fluocinonide in reducing scaling of knee/elbow lesions at weeks 8 and 12. Fluocinonide had a significantly greater effect on erythema than tazarotene at weeks 2 through 8. However, treatments were not significantly different at week 12, and tazarotene demonstrated significantly better maintenance of therapeutic effect after cessation of therapy. CONCLUSION: Tazarotene 0.1% and 0.05% gels were safe and effective in the treatment of mild-to-moderate plaque psoriasis.

The safety and efficacy of tazarotene gel, a topical acetylenic retinoid, in the treatment of psoriasis.

OBJECTIVE: To determine the safety and efficacy of topically applied tazarotene gel in the treatment of mild to moderate psoriatic plaques. DESIGN: Two multicenter, double-blind, randomized studies of 6- and 8-week duration, with an 8-week follow-up in the second study. SETTING: Medical center outpatient dermatology services. PARTICIPANTS: One hundred fifty-three adults with 2 bilateral target plaques on the trunk, legs, or arms. INTERVENTIONS: Vehicle gel or 0.01% and 0.05% tazarotene gel administered twice daily to 45 patients (study A), or 0.05% and 0.1% tazarotene gel administered either once or twice daily to 108 patients (study B). MAIN OUTCOME MEASURES: Treatment success and plaque elevation, scaling, and erythema vs time. RESULTS: The 0.01% tazarotene gel showed minimal efficacy. Applications of 0.05% and 0.1% tazarotene gels administered once or twice daily, resulted in significant improvements in plaque elevation, scaling, erythema, and overall clinical severity as early as 1 week. Treatment success rates (defined as > 75% improvement from baseline) were 45% with 0.05% tazarotene gel vs 13% with vehicle gel after 6 weeks of treatment (P < .05; study A) and ranged from 48% to 63% with the various tazarotene treatment regimens after 8 weeks of treatment (study B). These improvements were evident at the 8-week follow-up. Treatment-related adverse effects were generally limited to mild or moderate local irritation and were less frequent with the treatment regimen administered once daily. CONCLUSION: The 0.05% and 0.1% tazarotene gels demonstrated significant efficacy in the treatment of mild to moderate psoriatic plaques that persisted after cessation of treatment.

Tazarotene gel, a new retinoid, for topical therapy of psoriasis: vehicle-controlled study of safety, efficacy, and duration of therapeutic effect.

BACKGROUND: Topical therapy providing initial improvement and maintenance of effect after treatment of the large majority of patients with limited, mild to moderate psoriasis is not presently available. Previous topical retinoids have generally been either ineffective or too irritating for therapy of psoriasis. OBJECTIVE: Our purpose was to evaluate a new topical retinoid, tazarotene, in the treatment of stable plaque psoriasis during treatment and posttreatment periods. METHODS: In a double-blind manner, 324 patients were randomly selected to receive tazarotene 0.1% or 0.05% gel, or vehicle control, once daily for 12 weeks and were then followed up for 12 weeks after treatment. RESULTS: Of the total, 318 patients could be evaluated. Tazarotene gels were superior (p < 0.05) to vehicle, often as early as treatment week 1, in all efficacy measures: plaque elevation, scaling, and erythema; treatment response; percentage treatment success (patients with > or = 50% improvement); and time to initial success. Efficacy was equivalent on target lesion sites (trunk or limbs and knees or elbows) and overall. A sustained therapeutic effect was observed for 12 weeks after treatment. Tazarotene gel was cosmetically acceptable. There was low systemic absorption, limiting toxicity to local irritation. CONCLUSION: Once-daily tazarotene was effective and safe as a topical monotherapy for plaque psoriasis, providing rapid reduction of signs and symptoms.

Detection of antigen-antibody binding events with the atomic force microscope.

An atomic force microscope (AFM) has been used to directly monitor specific interactions between antibodies and antigens employed in an immunoassay system. Results were achieved using AFM probes functionalized with ferritin, and monitoring the adhesive forces between the probe and anti-ferritin antibody-coated substrates. Analysis of the force distribution data suggests a quantization of the forces, with a period of 49 +/- 10 pN. This periodic force may be attributed to single unbinding events between individual antigen and antibody molecules. These results demonstrate that the AFM could be employed as an analytical tool to study the interactions between the molecules involved in biosensor systems. The potential of the technique to provide information relating to the manner in which the antibody molecule binds to its specific antigen is also discussed.

In situ observation of streptavidin-biotin binding on an immunoassay well surface using an atomic force microscope.

Polystyrene microtitre wells are commonly used as supports for the enzyme-linked immunosorbent assay (ELISA) method of biomolecular detection, which is employed in the routine diagnosis of a variety of medical conditions. We have used an atomic force microscope (AFM) to directly monitor specific molecular interactions between individual streptavidin and biotin molecules on such wells. This was achieved by functionalising an AFM probe with biotin and monitoring the adhesive forces between the probe and a streptavidin coated immunoassay well. The results demonstrate that the AFM may be employed as an analytical tool to study the interactions between biomolecules involved in immunoassay systems.

Adsorption/desorption of amine fluorides to hydroxyapatite.

This study concerned the adsorption and desorption of commercial amine fluoride (AmF) preparations to hydroxyapatite (HA). The influence of pH, ionic strength, temperature, saliva and albumin, the latter as a gingival crevicular fluid analogue, on adsorption/desorption was investigated. AmF levels were determined using a surfactant electrode. AmFs 297 and 335 were found to bind immediately and irreversibly to HA in water over a range of pH values, ionic strengths and temperatures, the amounts increasing with concentration. More monovalent AmF 335 was absorbed than divalent AmF 297. Any AmF desorbed by water from HA was at the lowest end of the minimum inhibitory concentration for oral bacteria. AmF 297 was desorbed by CaCl2, and to a lesser extent by H+, OH-, NH4+, La3+, EDTA, Triton X100 and ethanol, whereas AmF 335 was only slightly desorbed by ethanol. Preadsorption of proteins on HA had little effect on subsequent adsorption or desorption of either AmF. It is postulated that both AmF 297 and AmF 335 are inactivated by an excess of proteins in the surrounding medium, supra- or subgingivally, and not by such proteins preventing or altering the mode or rate of adsorption, or interfering with antibacterial activity, when the AmFs contact a protein-coated tooth surface.

Response of psoriasis to a new topical retinoid, AGN 190168.

BACKGROUND: Oral retinoids have been widely used in psoriasis, but topical forms have been ineffective or irritating. OBJECTIVE: Our purpose was to determine the clinical and molecular effects of a new topical retinoid, AGN 190168, on psoriasis. METHODS: Seven patients with psoriasis were treated for 2 weeks with topical retinoid and 2 weeks with vehicle. Two control subjects with psoriasis were treated for 2 weeks with vehicle alone. Biopsy specimens from normal skin as well as from untreated and treated psoriatic lesions were compared by immunohistochemical analysis. Differentiation and inflammatory markers were studied. RESULTS: Clinical improvement was seen in all seven patients after 2 weeks of treatment. Improvement was still present, but not significant, after 2 additional weeks of vehicle application. Histologic examination showed a return to a more normal morphology in four of seven biopsy specimens, which correlated with filaggrin expression. There was a diminution in the precocious expression of keratinocyte transglutaminase, keratin 16, and involucrin, as well as a decrease in epidermal growth factor receptor and in the number of cells expressing intercellular adhesion molecule type 1 and HLA-DR. CONCLUSION: Clinical and histologic improvements were seen in psoriasis in association with the topical application of AGN 190168 at 2 weeks, including decreased inflammation and restoration of normal epidermal differentiation. Small patient numbers and the possibility that the changes were related to clinical improvement alone and not the topical agent preclude definitive conclusions.

Preliminary study of factors affecting the fluoride release from glass-ionomer cements.

A study has been made on the release of fluoride from three glass-ionomer cements. The effect of the maturity of cements at the time of immersion and powder/liquid ratio were examined. It was found that fluoride release from immature cements was dependent on cement and powder/liquid ratio and that the effect was permanent. The effect of cement type and powder/liquid ratio lessened as cements were allowed to mature prior to immersion. It appears that fluoride release was dependent on the strength and maturity of the cement matrix and not fluoride content. It was concluded that the rate of fluoride release would depend largely on clinical factors rather than cement type.