Ethne L. Nussbaum

Effects of 630-, 660-, 810-, and 905-nm laser irradiation delivering radiant exposure of 1-50 J/cm2 on three species of bacteria in vitro.

OBJECTIVE To examine the effects of low-intensity laser therapy (LILT) on bacterial growth in vitro. BACKGROUND DATA LILT is undergoing investigation as a treatment for accelerating healing of open wounds. The potential of coincident effects on wound bacteria has received little attention. Increased bacterial proliferation could further delay recovery; conversely inhibition could be beneficial. MATERIALS AND METHODS Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus were plated on agar and then irradiated with wavelengths of 630, 660, 810, and 905 nm (0.015 W/cm(2)) and radiant exposures of 1-50 J/cm(2). In addition, E. coli was irradiated with 810 nm at an irradiance of 0.03 W/cm(2) (1-50 J/cm(2)). Cells were counted after 20 h of incubation post LILT. Repeated measures ANOVA and Tukey adjusted post hoc tests were used for analysis. RESULTS There were interactions between wavelength and species (p = 0.0001) and between wavelength and radiant exposure (p = 0.007) in the overall effects on bacterial growth; therefore, individual wavelengths were analyzed. Over all types of bacteria, there were overall growth effects using 810- and 630-nm lasers, with species differences at 630 nm. Effects occurred at low radiant exposures (1-20 J/cm(2)). Overall effects were marginal using 660 nm and negative at 905 nm. Inhibition of P. aeruginosa followed irradiation using 810 nm at 5 J/cm(2) (-23%; p = 0.02). Irradiation using 630 nm at 1 J/cm(2) inhibited P. aeruginosa and E. coli (-27%). Irradiation using 810 nm (0.015 W/cm(2)) increased E. coli growth, but with increased irradiance (0.03 W/cm(2)) the growth was significant (p = 0.04), reaching 30% at 20 J/cm(2) (p = 0.01). S. aureus growth increased 27% following 905-nm irradiation at 50 J/cm(2). CONCLUSION LILT applied to wounds, delivering commonly used wavelengths and radiant exposures in the range of 1-20 J/cm(2), could produce changes in bacterial growth of considerable importance for wound healing. A wavelength of 630 nm appeared to be most commonly associated with bacterial inhibition. The findings of this study might be useful as a basis for selecting LILT for infected wounds.

Effects of Low-Level Laser Therapy (LLLT) of 810 nm upon in Vitro Growth of Bacteria: Relevance of Irradiance and Radiant Exposure

OBJECTIVE The aim of this study was to investigate the irradiance-dependency of low-level laser therapy (LLLT) effects on bacterial growth. BACKGROUND LLLT is applied to open wounds to improve healing; however, its effect on wound bacteria is not well understood. MATERIALS AND METHODS Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were irradiated using a wavelength of 810 nm at irradiances of 0.015 W/cm2 (0-50 J/cm2) and 0.03 W/cm2 (0-80 J/cm2). Bacteria were counted after 20 h of incubation. RESULTS LLLT effects varied significantly with species. P.aeruginosa growth decreased overall dependent on an interaction of irradiance and radiant exposure; greatest inhibition was produced using high irradiance delivering radiant exposures in the range of 1-20 J/cm2 (p = 0.001-0.04). In contrast, E. coli growth increased overall (p = 0.01), regardless of irradiance; greatest effects were produced using low radiant exposures (1-20 J/cm2). There was a main effect for irradiance (p = 0.03) on S. aureus growth; however, growth was not different compared with controls. Additional analysis showed that there were differences in growth of P.aeruginosa when comparing samples that were matched by exposure times (66, 329, 658, 1316, 1974, and 2632 sec) rather than radiant exposure; this suggests that irradiance rather than exposure time was the significant factor in P. aeruginosa inhibition. CONCLUSION These findings have immediate relevancy in the use of LLLT for infected wounds. Exposure to 810-nm irradiation (0.03 W/cm2) could potentially benefit wounds infected with P. aeruginosa. However, increased E. coli growth could further delay recovery.

The influence of ultrasound on healing tissues.

This paper identifies techniques in ultrasound that influence healing tissues. The importance of appropriate parameters is emphasized. Current literature is reviewed to support the use of ultrasound in specific conditions and different phases of healing. Types of wounds discussed include delayed-closure wounds, deep soft-tissue wounds, tendon and nerve repairs, bone fracture, and burn injury. There is a need for research in ultrasound directly related to hand therapy.

A Review of Laser Technology and Light-Tissue Interactions as a Background to Therapeutic Applications of Low Intensity Lasers and Other Light Sources

Abstract This paper reviews aspects of laser physics, radiometry and photochemistry relevant to the use of low intensity light therapy delivered by lasers or conventional lamps. Current theories regarding the biophysical mechanisms of low intensity laser therapy are reviewed. Characteristics of laser radiation such as monochromaticity, coherence, collimation, speckle, beam profile, penetration depth and temporal modulation of irradiation, and the relevance of these factors to photon propagation are explained. Physical principles that describe light–tissue interactions are presented. The importance of irradiance and radiant exposure is discussed and methods of quantifying these values are shown. Clinical implications are briefly discussed.

Continuous and pulsed ultrasound do not increase heat shock protein 72 content

Therapeutic ultrasound (US) is a common treatment used in the rehabilitation of injured muscle. To determine whether therapeutic US could increase the content of heat shock protein (HSP) 72 in skeletal muscle, male Sprague-Dawley rats were anesthetized and the muscles from one hind limb treated with 15 min of US at 1 MHz using either: 1. continuous US at 1.0 W/cm(2), 2. pulsed US at 2.0 W/cm(2) at 50% duty cycle, or 3. pulsed US at 1.0 W/cm(2) at 20% duty cycle. All treatments were applied using a transducer (1.6-cm diameter) on an area of the rat hind limb twice the size of the sound head. At 24 h following treatment, the plantaris, soleus, white and red gastrocnemius muscles were removed and assessed for HSP 72 content by Western blotting. No significant increases in HSP 72 content were detected in any of the muscles examined following any US treatment. These results suggest muscle HSP content is not elevated following a typical therapeutic dose of either continuous or pulsed US in the rat.

EFFECTS OF LOW INTENSITY LASER IRRADIATION DURING HEALING OF SKIN LESIONS IN THE RAT

To determine whether laser light can improve healing of skin wounds by killing wound bacteria while simultaneously accelerating host tissue activity.

The Effects of Interferential Therapy on Peripheral Blood Flow

Summary The purpose of this study was to determine whether vasodilation occurs when interferential therapy (IF) is applied to the cervical sympathetic chain and stellate ganglion; the dorso-lumbar sympathetic outflow; and peripheral sympathetic nerves. Using thermography to record skin temperature changes, vasodilation was not detected with any protocol or electrode placement. The protocols used for stimulation were 0—100 Hz, 0–150 Hz and 90–100 Hz, applied for 20 minutes via two pairs of electrodes. Fifty-five subjects were each tested once only. One protocol included a cold stress test on the hands prior to stimulation. Variables such as initial skin temperature, sex and age had no significant influence on results. We conclude that IF does not cause vasodilation. More research on IF is needed so that the potential benefit to patients is understood.

Effects of low intensity laser irradiation during healing of infected skin wounds in the rat

Abstract Background and objective: Low intensity laser irradiation remains a controversial treatment for non-healing wounds. This study examines the effect of low intensity light on healing of infected skin wounds in the rat. Materials and methods: Wounds on the rat dorsum were inoculated with Pseudomonas aeruginosa. Wounds were irradiated or sham-irradiated three times weekly from day 1 to 19 using 635-nm or 808-nm diode lasers delivering continuous wave (CW) or intensity modulated (3800 Hz) laser radiation, all at radiant exposures of 1 and 20 J/cm2. Wound area and bacterial growth on the wound surface were evaluated three times a week. Histological and immunohistochemical analyses were performed at day 8 and 19. Results: Wounds that were irradiated using a wavelength of 635 nm (1 and 20 J/cm2) or intensity modulated 808-nm laser light at 20 J/cm2 were smaller in area at day 19 than the sham-irradiated controls (achieved significance level=0.0105–0.0208) and were similar to controls in respect of bacterial growth. The remaining light protocols had no effect on wound area at day 19 although they increased Staphylococcus aureus growth across the time line compared with controls (p<0.0001 to p<0.004). CW 808-nm light at 20 J/cm2 significantly delayed half-heal time. Histological and immunohistochemical analyses supported wound closure findings: improved healing was associated with faster resolution of inflammation during the acute phase and increased signs of late repair at day 19. Significant inflammation was seen at day 19 in all irradiated groups regardless of radiant exposure, except when using 635 nm at 1 J/cm2. Conclusions: Red light improved healing of wounds. Only one 808-nm light protocol enhanced healing; lack of benefit using the remaining 808-nm light protocols may have been due to stimulatory effects of the light on S. aureus growth. Zusammenfassung Hintergrund und Zielsetzung: Low-Intensity-Laserbestrahlung bleibt eine umstrittene Behandlung von nicht heilenden Wunden. Diese Studie untersucht die Wirkung von Laserlicht niedriger Intensität auf die Heilung von infizierten Wunden der Haut am Rattenmodell. Materialien und Methoden: Wunden auf dem Rücken von Ratten wurden mit dem Pseudomonas aeruginosa geimpft und anschließend dreimal wöchentlich, beginnend am Tag 1 bis zum Tag 19, bestrahlt oder scheinbestrahlt. Für die Laserbestrahlung wurden ein kontinuierlich abstrahlender (continuous wave, cw) 635 nm-Diodenlaser oder ein 808 nm-Diodenlaser im cw- bzw. intensitätsmodulierten (3800 Hz) Modus verwendet, jeweils mit einer Energiedichte von 1 und 20 J/cm2. Die Wundbereiche und das Bakterienwachstum an der Wundoberfläche wurden dreimal wöchentlich ausgewertet. Histologische und immunhistochemische Analysen wurden am Tag 8 und 19 durchgeführt. Ergebnisse: Wunden, die mit einer Wellenlänge von 635 nm (1 und 20 J/cm2) oder mit intensitätsmoduliertem 808 nm-Laserlicht bei 20 J/cm2 bestrahlt wurden, waren am Tag 19 in der Fläche kleiner als die scheinbestrahlten Proben (erreichtes Signifikanzniveau=0,0105 bis 0,0208) und in Bezug auf das Bakterienwachstum vergleichbar mit der Kontrollgruppe. Die anderen Bestrahlungsprotokolle hatten keinen Einfluss auf den Wundbereich am Tag 19, führten über die Zeit aber zu einem im Vergleich zur Kontrollgruppe erhöhten Staphylococcus aureus-Wachstum (p<0,0001 bis p<0,004). Hingegen hat die kontinuierliche 808 nm-Laserbestrahlung mit 20 J/cm2 die Heilung verzögert. Die histologischen und immunhistochemischen Analysen unterstützen die Wundverschlussbefunde: die verbesserte Heilung ging mit einem schnellen Rückgang der Entzündung während der akuten Phase einher und es gab erhöhte Anzeichen für eine späte Reparatur am Tag 19. In allen bestrahlten Gruppen und unabhängig von der verwendeten Energiedichte – außer bei der Verwendung von 635 nm bei 1 J/cm2 – wurde am Tag 19 eine deutliche Entzündung gesehen. Schlussfolgerungen: Rotes Licht verbessert die Heilung von Wunden. Nur ein 808 nm-Bestrahlungsprotokoll verbesserte die Heilung; der fehlende Nutzen der restlichen 808 nm-Bestrahlungsprotokolle lässt sich möglicherweise auf die stimulierende Wirkung des Lichts auf das S. aureus-Wachstum zurückführen.

A study of the utility and equivalency of 2 methods of wound measurement: digitized tracing versus digital photography.

OBJECTIVE: To examine agreement between digitized tracing and digital photography methods in measuring wound area and healing rate, and to compare and contrast the 2 methods on feasibility and utility in patient care and research settings. SETTING: Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada. PARTICIPANTS: A total of 20 subjects aged 18 years or older with a spinal cord injury and pressure ulcers that were Stage II or higher, and who had received in- or outpatient wound care at the hospital for at least 3 consecutive weeks. METHODS: Wound area was measured at weekly intervals. One assessor calculated wound area from a digitized tracing. A second assessor calculated wound area using a wound photograph. Both assessors used Image-J software. The 2 methods were compared for differences in weekly wound area and weekly healing rate. RESULTS: Methods were different for wound area (P < .0001), whereas there was no difference between methods in weekly healing rate (P = .9429). CONCLUSIONS: The 2 methods are in agreement on the important parameter of healing rate. Both methods are feasible in clinical settings. Wound photography may be more useful than digitized tracings because it simultaneously captures wound appearance.

Rebox effect on exercise-induced acute inflammation in human muscle

OBJECTIVE To evaluate the effect of Rebox stimulation on an experimental model of soft tissue inflammation. DESIGN Randomized trial, partially blinded, comparing a control group with active and placebo Rebox. SUBJECTS Thirty healthy volunteers, 15 women. METHODS Delayed onset muscle soreness was induced in biceps brachii muscle by weighted eccentric exercise. Rebox stimulation was applied daily for 3 days using a negatively charged probe electrode, at pulse duration of 100 microsec, amplitude of 160 microamp, and frequency of 3000 Hz. OUTCOME MEASURES DAILY ratings of pain by visual analogue scale (VAS), and tenderness by pressure-pain threshold (PPT) and pressure-pain tolerance (PT). RESULTS Significant increases in VAS and decreases in PPT and PT were found at 24 and 48 hours. There were no differences between groups. CONCLUSION Rebox had no effect on this experimental model of soft tissue injury.