Low-level laser therapy (LLLT) modulates various biological processes. In the present study, we assessed the hypothesis that LLLT after induction of stroke may have a beneficial effect on ischemic ...brain tissue.
Two sets of experiments were performed. Stroke was induced in rats by (1) permanent occlusion of the middle cerebral artery through a craniotomy or (2) insertion of a filament. After induction of stroke, a battery of neurological and functional tests (neurological score, adhesive removal) was performed. Four and 24 hours poststroke, a Ga-As diode laser was used transcranially to illuminate the hemisphere contralateral to the stroke at a power density of 7.5 mW/cm2.
In both models of stroke, LLLT significantly reduced neurological deficits when applied 24 hours poststroke. Application of the laser at 4 hours poststroke did not affect the neurological outcome of the stroke-induced rats as compared with controls. There was no statistically significant difference in the stroke lesion area between control and laser-irradiated rats. The number of newly formed neuronal cells, assessed by double immunoreactivity to bromodeoxyuridine and tubulin isotype III as well as migrating cells (doublecortin immunoactivity), was significantly elevated in the subventricular zone of the hemisphere ipsilateral to the induction of stroke when treated by LLLT.
Our data suggest that a noninvasive intervention of LLLT issued 24 hours after acute stroke may provide a significant functional benefit with an underlying mechanism possibly being induction of neurogenesis.
Low-level laser therapy (LLLT) has been evaluated in this study as a potential therapy for traumatic brain injury (TBI). LLLT has been found to modulate various biological processes. Following TBI in ...mice, we assessed the hypothesis that LLLT might have a beneficial effect on their neurobehavioral and histological outcome. TBI was induced by a weight-drop device, and motor function was assessed 1 h post-trauma using a neurological severity score (NSS). Mice were then divided into three groups of eight mice each: one control group that received a sham LLLT procedure and was not irradiated; and two groups that received LLLT at two different doses (10 and 20 mW/cm(2) ) transcranially. An 808-nm Ga-As diode laser was employed transcranially 4 h post-trauma to illuminate the entire cortex of the brain. Motor function was assessed up to 4 weeks, and lesion volume was measured. There were no significant changes in NSS at 24 and 48 h between the laser-treated and non-treated mice. Yet, from 5 days and up to 28 days, the NSS of the laser-treated mice were significantly lower (p < 0.05) than the traumatized control mice that were not treated with the laser. The lesion volume of the laser treated mice was significantly lower (1.4%) than the non-treated group (12.1%). Our data suggest that a non-invasive transcranial application of LLLT given 4 h following TBI provides a significant long-term functional neurological benefit. Further confirmatory trials are warranted.
Near-infrared transcranial laser therapy (TLT) has been found to modulate various biological processes including traumatic brain injury (TBI). Following TBI in mice, in this study we assessed the ...possibility of various near-infrared TLT modes (pulsed versus continuous) in producing a beneficial effect on the long-term neurobehavioral outcome and brain lesions of these mice. TBI was induced by a weight-drop device, and neurobehavioral function was assessed from 1 h to 56 days post-trauma using the Neurological Severity Score (NSS). The extent of recovery is expressed as the difference in NSS (dNSS), the difference between the initial score and that at any other later time point. An 808-nm Ga-Al-As diode laser was employed transcranially 4, 6, or 8 h post-trauma to illuminate the entire cortex of the brain. Mice were divided into several groups of 6-8 mice: one control group that received a sham treatment and experimental groups that received either TLT continuous wave (CW) or pulsed wave (PW) mode transcranially. MRI was taken prior to sacrifice at 56 days post-injury. From 5-28 days post-TBI, the NSS of the laser-treated mice were significantly lower (p<0.05) than those of the non-laser-treated control mice. The percentage of surviving mice that demonstrated full recovery at 56 days post-CHI (NSS=0, as in intact mice) was the highest (63%) in the group that had received TLT in the PW mode at 100 Hz. In addition, magnetic resonance imaging (MRI) analysis demonstrated significantly smaller infarct lesion volumes in laser-treated mice compared to controls. Our data suggest that non-invasive TLT of mice post-TBI provides a significant long-term functional neurological benefit, and that the pulsed laser mode at 100 Hz is the preferred mode for such treatment.
Dr. Harold E. Kleinert's 90th Birthday Oron, Amir, MD
The Journal of hand surgery (American ed.),
2012, 2012-Jan, 2012-1-00, 20120101, Letnik:
37, Številka:
1
Journal Article
This communication reviews the ability of low-level laser therapy (LLLT) to stimulate mesenchymal stem cells (MSCs) in autologous bone marrow (BM) to enhance the capacity of MSCs to infiltrate the ...brain, clear β-amyloid, and improve cognition.
We recently reported that LLLT applied to the BM enhanced the proliferation of MSCs and their mobilization toward the ischemic heart region, suggesting a possible application of this approach in regenerative medicine and neurodegenerative diseases. It was also shown that circulating monocytes can infiltrate the brain and reduce brain amyloid load in an Alzheimer's disease (AD) mouse model.
MSCs from wild-type mice stimulated with LLLT demonstrated an increased ability to maturate toward a monocyte lineage and to increase phagocytosis of soluble Aβ in vitro. Furthermore, weekly LLLT for 2 months to the BM, starting at 4 months of age (progressive stage of the disease in these 5XFAD transgenic male mice), improved memory and spatial learning, compared to a sham-treated AD mouse model. Histology revealed a significant reduction in Aβ brain burden in the laser-treated mice compared to the nonlaser-treated ones.
The application of LLLT to the BM is suggested as a therapeutic approach in progressive stages of AD, and its potential role in mediating MSC therapy in brain amyloidogenic disease is implied.
The aim of the present study was to investigate the possible short- and long-term adverse neurological effects of low-level laser therapy (LLLT) given at different power densities, frequencies, and ...modalities on the intact rat brain.
LLLT has been shown to modulate biological processes depending on power density, wavelength, and frequency. To date, few well-controlled safety studies on LLLT are available.
One hundred and eighteen rats were used in the study. Diode laser (808 nm, wavelength) was used to deliver power densities of 7.5, 75, and 750 mW/cm2 transcranially to the brain cortex of mature rats, in either continuous wave (CW) or pulse (Pu) modes. Multiple doses of 7.5 mW/cm2 were also applied. Standard neurological examination of the rats was performed during the follow-up periods after laser irradiation. Histology was performed at light and electron microscopy levels.
Both the scores from standard neurological tests and the histopathological examination indicated that there was no long-term difference between laser-treated and control groups up to 70 days post-treatment. The only rats showing an adverse neurological effect were those in the 750 mW/cm2 (about 100-fold optimal dose), CW mode group. In Pu mode, there was much less heating, and no tissue damage was noted.
Long-term safety tests lasting 30 and 70 days at optimal 10x and 100x doses, as well as at multiple doses at the same power densities, indicate that the tested laser energy doses are safe under this treatment regime. Neurological deficits and histopathological damage to 750 mW/cm2 CW laser irradiation are attributed to thermal damage and not due to tissue-photon interactions.
Low-energy laser irradiation (LELI) has been found to attenuate various biological processes in tissue culture and experimental animal models. The aim of the present study was to investigate the ...effect of LELI on the formation of scar tissue in experimentally induced chronic infarct in rats and dogs.
Myocardial infarction (MI) was induced in 50 dogs and 26 rats by ligation of the left anterior descending coronary artery. After induction of MI, the laser-irradiated (LI) group received laser irradiation (infrared laser, 803-nm wavelength) epicardially. Control MI-induced non-laser irradiated (NLI) dogs were sham-operated, and laser was not applied. All dogs were euthanized at 5 to 6 weeks after MI. Infarct size was determined by TTC staining and histology. The laser treatment (P:<0.05) lowered mortality significantly, from 30% to 6.5%, after induction of MI. The infarct size in the LI dogs was reduced significantly (P:<0.0001) (52%) compared with NLI dogs. Histological observation of the infarct revealed a typical scar tissue in NLI dogs and cellularity in most of the LI dogs. Only 14+/-3% of the mitochondria in the cardiomyocytes in the ischemic zone (4 hours after MI) of LI MI-induced rats were severely damaged, compared with 36+/-1% in NLI rats. Accordingly, ATP content in that zone was 7.6-fold (significantly) higher in LI than in NLI rats.
Our observations indicate that epicardial LELI of rat and dog hearts after chronic MI caused a marked reduction in infarct size, probably due to a cardioprotective effect of the LELI.
Background:
Gender diversity in medicine can improve physician-patient interactions. Although the number of female medical students has risen to almost 50%, the relative number of female orthopaedic ...residents remains low. The reason for so few female applicants to orthopaedic programs remains in question.
Methods:
A web survey was distributed to medical students and interns in Israel in 2015 and again in 2018. The survey included demographic data and a questionnaire. The questionnaire explored reasons for not choosing orthopaedics as a specialty and exposure to musculoskeletal medicine in medical school.
Results:
A total of 371 responses were received, 143 in 2015 and 228 in 2018. The distribution of gender, marital status, student status, and medical schools were similar. Men were more inclined to choose orthopaedics in both years (
P
=0.004,
P
=0.044). The major reason for not choosing orthopaedics was “it’s just not interesting.” However, in 2018, there were a significant number of male responders who wanted a more balanced work-life profession (
P
=0.047).
Conclusions:
Women have given many possible reasons for not choosing orthopaedic surgery, such as wanting a better work-life balance, perceptions of physical strength needed, a closed “boy’s club,” not enough exposure, and lack of female role models, yet most of them replied the field is “just not interesting.” The authors suggest in concordance to the literature that having more opportunity for exposure and more female role models would increase gender diversity in orthopaedics.
Level of Evidence:
Level IV.
The human wrist is a composite joint which incorporates multiple smaller joints. The biomechanics of the wrist are dependent on its bony structure but also on the ligamentous constitution of its ...joints. This increases the complexity of the joint and reduces our ability to understand its anatomy, mechanics and pathology. Therefore, our understanding and treatment of osteoarthritis in the wrist lags behind that of other joints in the body such as the knee. We discuss some of the recent directions in the comprehension and treatment of wrist osteoarthritis.
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