Photobiomodulation Therapy in Veterinary Medicine: A Review

Laser therapy, or photobiomodulation, has rapidly grown in popularity in human and veterinary medicine. With a number of proposed indications and broad, sometimes anecdotal, use in practice, research interest has expanded aimed at providing scientific support. Recent studies have shown that laser therapy alters the inflammatory and immune response as well as promotes healing for a variety of tissue types. This review will cover the history of the modality, basic principles, proposed mechanisms of action, evidence-based clinical indications, and will guide the practitioner through its application in practice.     

The fate of organic matter derived from small-scale fish cage aquaculture in coastal waters of Sulawesi and Sumatra, Indonesia

To determine the fate of organic matter derived from fish cage aquaculture, carbon and nutrient cycling processes in waters and sediments, and water circulation, were examined at two fish cage farms of different size and utilizing different food types, on Sulawesi and Sumatra islands, Indonesia. Mass balance models of C, N and P were constructed to assess the pathways of waste utilization and dispersal. At the smaller farm in Sulawesi (64.5 m² cage area; 3 t annual net production) using pelleted food, there was proportionally less waste (≈ 40% of total C input) than at the larger Sumatran farm (2432 m² cage area; 9 t annual net production) using trash fish (≈ 70% of total C input) as food. At the small farm, the mass balance and hydrographic models indicated a maximum dispersal area of 1180 m², equivalent to 18 times the farm area. Within this area, 30% of total organic matter input (farm waste + fixed phytoplankton carbon) was buried in sediments with 30% mineralized in the water-column and 40% mineralized in the seabed. At the larger Sumatran farm, the models indicated a maximum dispersal area of 29  220 m², roughly 12 times the farm area. Within this area, 30% of total organic matter input (farm waste + natural pelagic input) was buried in sediments with 50% mineralized in the water-column and 20% mineralized on the seabed. There was some evidence of benthic enrichment at both farms, mostly as enhanced dissolved nutrient release, but sulfate reduction accounted for < 25% of total C flux, and denitrification/ammonium oxidation accounted for only 4–17% of N lost from sediments. There was no clear evidence of impact with distance from the cages at either farm. Phytoplankton gross primary production accounted for 60–77% of the total organic input to the receiving environment, suggesting that the relative importance of fish cage wastes must be assessed against natural inputs of organic matter.     

Neosporosis in cats

Six cats (Nos. 1-6) were inoculated intramuscularly with (1 x 10(6)) and orally (5 x 10(5)) tachyzoites of Neospora caninum. Three (Nos. 1-3) of the six cats were given 40 mg/kg methylprednisolone acetate 7 days before and on the day of inoculation with N. caninum tachyzoites, and three cats (Nos. 4-6) were not given methylprednisolone acetate. Two of the cats (cat Nos. 1 and 2) given methylprednisolone acetate died suddenly. Cat No. 1 died 8 days post-inoculation, and cat No. 2 died 16 days post-inoculation. Cat No. 3 was euthanatized 21 days post-inoculation. Cat No. 1 had lesions of gram-positive bacterial septicemia. Necrotizing encephalitis, myelitis, disseminated skeletal muscle necrosis, hepatic necrosis, interstitial pneumonia, and renal tubular necrosis were the main lesions in cat Nos. 2 and 3. The cats that were not given methylprednisolone acetate remained clinically normal except for slight weight loss in cat No. 6. All three of these cats were euthanatized 55 days post-inoculation. Mild myositis and encephalitis were noted on microscopic examination of tissues from these three cats. Neuromuscular lesions were not seen in six control cats (Nos. 7-12) not inoculated with N. caninum and euthanatized 21 or 22 days after administration of the first two doses of methylprednisolone acetate (40 mg/kg), given at a weekly interval.     

Prevalence of Sarcocystis neurona sporocysts in opossums (Didelphis virginiana) from rural Mississippi

Sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 opossums (Didelphis virginiana) from rural Mississippi. The number of sporocysts in each opossum varied from a few ( < 100000) to 187 million. Sporocysts from 24 opossums were bioassayed for Sarcocystis neurona infections by feeding to gamma-interferon knockout (KO) mice. S. neurona was detected in the brains of KO mice fed sporocysts from 19 opossums by immunohistochemical staining with anti-S. neurona specific polyclonal rabbit serum, and by in vitro culture from the brains of KO mice fed sporocysts. The isolates of S. neurona from opossums were designated SN16-OP to SN34-OP. Merozoites from 17 of 19 isolates tested at the 25/396 locus were identical to previously described S. neurona isolates from horses. The high prevalence of S. neurona sparocysts in D. virginiana suggests that this opossum constitutes an ample reservoir of infection in the southern United States.     

Noncanonical TGFβ signaling contributes to aortic aneurysm progression in Marfan syndrome mice

Transforming growth factor-β (TGFβ) signaling drives aneurysm progression in multiple disorders, including Marfan syndrome (MFS), and therapies that inhibit this signaling cascade are in clinical trials. TGFβ can stimulate multiple intracellular signaling pathways, but it is unclear which of these pathways drives aortic disease and, when inhibited, which result in disease amelioration. Here we show that extracellular signal-regulated kinase (ERK) 1 and 2 and Smad2 are activated in a mouse model of MFS, and both are inhibited by therapies directed against TGFβ. Whereas selective inhibition of ERK1/2 activation ameliorated aortic growth, Smad4 deficiency exacerbated aortic disease and caused premature death in MFS mice. Smad4-deficient MFS mice uniquely showed activation of Jun N-terminal kinase-1 (JNK1), and a JNK antagonist ameliorated aortic growth in MFS mice that lacked or retained full Smad4 expression. Thus, noncanonical (Smad-independent) TGFβ signaling is a prominent driver of aortic disease in MFS mice, and inhibition of the ERK1/2 or JNK1 pathways is a potential therapeutic strategy for the disease.     

Confirmation that the dog is a definitive host for Neospora caninum.

Two mixed-breed littermate dogs were fed mouse brains containing tissue cysts of the NC-beef isolate of Neospora caninum. Both dogs excreted N. caninum oocysts in their feces. Dog 1 which was given methylprednisolone acetate (MPA) prior to ingesting tissue cysts, excreted oocysts on days 5 to 10 inclusive and on day 17 after ingesting tissue cysts. Dog 1 had a serum antibody titer of 1:200 in the indirect fluorescent antibody test (IFAT) 35 days after it was fed tissue cysts. Dog 2, which was not treated with MPA, excreted oocysts on Day 6 and Day 9 after ingesting tissue cysts. Antibodies to N. caninum were not found in a 1:25 dilution of serum on any examination period for Dog 2 during the study. Neospora caninum was not found in the tissues of either dog by histological or immunohistochemical means following necropsy 42 days after being fed tissue cysts. The identity of the oocysts excreted in the feces of the dogs was confirmed by mouse inoculation studies.     

Determination of the activity of pyrantel tartrate against Sarcocystis neurona in gamma-interferon gene knockout mice

Equine protozoal myeloencephalitis (EPM) is the most important protozoal disease of horses in the United States. Some horse owners and equine clinicians believe that horses which are on daily pyrantel tartrate at 2.64mg/kg for helminth prophylaxis are less likely to develop EPM. The present study examined the efficacy of pyrantel tartrate in preventing clinical disease in gamma-interferon gene knockout (BALB/c-Ifng(tm1ts)) mice. No activity was seen against sporocyst-induced Sarcocystis neurona infections in mice treated prophylacticly with 4-5mg pyrantel tartrate per mouse per day in the drinking water.     

Flow cytometric analysis of cellular immune responses in dogs experimentally infected with a North American isolate of Leishmania infantum

Canine leishmaniasis caused by Leishmania infantum is endemic in the foxhound population in North America. Studies of canine leishmaniasis in the Mediterranean basin indicate a role for both CD4+ and CD8+ lymphocytes with clinical illness and in asymptomatic dogs. Limited information is available on the strain of L. infantum infecting foxhounds in North America. The present study investigated changes in cellular immune responses in dogs experimentally infected with 1x10(7) (low dose, LD; N=4) or 2x10(8) (high dose, HD; N=4) promastigotes of a United States isolate of L. infantum and control dogs (N=2) for 72 weeks. Density gradient separation was used to enrich for peripheral blood lymphocytes from canine blood. Lymphocyte subsets (CD4+ and CD8+) were quantified by flow cytometric analysis. Lymphocyte population expression levels over the course of the present study were compared to clinical status of the dog and antibody responses in infected and control dogs. No significant differences (P>0.05) were observed in either CD4+ or CD8+ lymphocyte expression in of the groups over the experimental period. This study suggests that the cellular immune responses to North American L. infantum in experimentally infected dogs may differ from other strains of L. infantum.