Development of secondary mutations in wild-type and mutant EZH2 alleles cooperates to confer resistance to EZH2 inhibitors.

The histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2) is frequently dysregulated in cancers, and gain-of-function (GOF) EZH2 mutations have been identified in non-Hodgkin lymphomas. Small-molecule inhibitors against EZH2 demonstrated anti-tumor activity in EZH2-mutated lymphomas and entered clinical trials. Here, we developed models of acquired resistance to EZH2 inhibitor EI1 with EZH2-mutated lymphoma cells. Resistance was generated by secondary mutations in both wild-type (WT) and GOF Y641N EZH2 alleles. These EZH2 mutants retained the substrate specificity of their predecessor complexes but became refractory to biochemical inhibition by EZH2 inhibitors. Resistant cells were able to maintain a high level of H3K27Me3 in the presence of inhibitors. Interestingly, mutation of EZH2 WT alone generated an intermediate resistance phenotype, which is consistent with a previously proposed model of cooperation between EZH2 WT and Y641N mutants to promote tumorigenesis. In addition, the findings presented here have implications for the clinical translation of EZH2 inhibitors and underscore the need to develop novel EZH2 inhibitors to target potential resistance emerging in clinical settings.

Changes in phytoplankton composition in response to tides, wind-induced mixing conditions, and freshwater outflows in an urbanised estuarine complex.

Recent reports have shown an increase in potentially harmful phytoplankton in Santos bay (Southeastern Brazilian Coast), located in a highly urbanised estuarine complex. Prediction of blooms is, thus, essential but the phytoplankton community structure in very dynamic regions is difficult to determine. In the present work, we discriminate bloom forming microphytoplankton dominance and their relationship to physical and meteorological variables to look for patterns observed in different tides and seasons. Comparing 8 distinct situations, we found five scenarios of dominance that could be related to winds, tides and rainfall: i) Surfers, diatoms occurring during high surf zone energies; ii) Sinkers, represented by larger celled diatoms during spring tide, after periods of high precipitation rates; iii) Opportunistic mixers, composed of chain forming diatoms with small or elongate cells occurring during neap tides; iv) Local mixers, microplanktonic diatoms and dinoflagellates which occurred throughout the 298 sampling stations; and v) Mixotrophic dinoflagellates, after intense estuarine discharges. Results suggest alterations in the temporal patterns for some bloom-forming species, while others appeared in abundances above safe limits for public health. This approach can also illustrate possible impacts of changes in freshwater discharge in highly urbanised estuaries.

Optical devices for ultra-compact photonic integrated circuits based on III-V/polymer nanowires.

We demonstrated the potential application of III-V/polymer nanowires for photonic integrated circuits in a previous paper. Hereby, we report the use of a spot size converter based on 2D reverse nanotaper structure in order to improve the coupling efficiency between the nanowire and optical fiber. A total coupling enhancement of up to a factor 60 has been measured from an 80 nm x 300 nm cross-section tip which feeds an 300 nm-side square nanowire at its both ends. Simultaneously, micro-radius bends have been fabricated to increase the circuit density; for a radius of 5 microm, the 90 masculine bend losses were measured as low as 0.60 dB and 0.80 dB for TE and TM polarizations respectively.

Osteochondrosis of the femur.

Osteochondrosis can occur in the stifle joint(s) of young, rapidly growing large breeds of dogs. Although not as common as osteochondrosis of the shoulder, elbow, and hock joints, the osteochondral defect in the femoral condyle(s) and stifle joint fragment can cause a clinically apparent lameness. Radiography is beneficial in identifying the lesion(s), and surgical therapy is useful in restoring limb function.

Clinical evaluation of the osteoarthritic patient.

Clinical evaluation of the osteoarthritic patient involves critical evaluation off the animal and associated medical history. The most useful diagnostic aids in veterinary practice include joint palpation, radiography, and arthrocentesis. Accurate patient assessment provides diagnostic and prognostic information as well as serving as a baseline for medical or surgical therapies.

Bone fracture and sequestration as complications of external skeletal fixation.

A transverse tibial fracture and bone sequestrum at the pin-bone interface were diagnosed in a dog treated with external skeletal fixation for tarsal arthrodesis. The causes of the bone fracture were improper use of external fixator pins and trauma after the fixator became entangled in a fence. After removal of the original fixator, the tibial fracture was successfully repaired with an intramedullary pin, a type II external skeletal fixator and an autogenous cancellous bone graft. Bone sequestration and draining sinuses were successfully treated with curettage and antimicrobial therapy.

Gunshot injuries: pathophysiology and treatments.

The increase in gun ownership and shootings of dogs and cats in urban and rural areas has made it important for veterinarians to be familiar with the treatment of gunshot injuries. The damage inflicted on the soft tissues and bone depends on the type of firearm used and the range at which it was fired. Proper initial evaluation and management are critical in the treatment of these injuries. Fractures caused by gunshots are contaminated and can often be stabilized with external fixation. Complications and special considerations of these fractures and associated soft tissue injuries are discussed.

Surgical treatments for prostatic diseases in dogs.

Successful prostatic surgery requires aggressive perioperative animal patient management, accurate identification of the disease process, and proper surgical techniques. Overcoming the complications associated with urinary incontinence, sepsis, and neoplasia will help reduce animal patient morbidity and mortality.

Evaluation of the lateral collateral ligament after fibular head transposition in dogs.

Cranial transposition of the fibular head stabilizes the stifle joint by displacing the distal attachment of the lateral collateral ligament (LCL). The forces applied to the LCL after displacement may cause ligamentous elongation. This investigation evaluated the morphological, histological, and biomechanical changes of the LCL after fibular head transposition (FHT) in dogs. Unilateral cranial cruciate ligament (CCL) excision and FHT were performed on 25 dogs. Cross-sectional area, length, histological, and structural properties of the LCL were evaluated 3 weeks, 4 months, and 10 months after surgery. Ligament length means were significantly increased at week 3, month 4, and month 10 compared with intraoperative length means. No significant changes in elongation were observed after week 3. Fibrovascular proliferation within the LCL increased the cross-sectional area and associated structural properties.

Evaluation of fibular head transposition for repair of experimental cranial cruciate ligament injury in dogs.

Unilateral cranial cruciate ligament excision and fibular head transposition (FHT) were performed on 30 adult dogs. Vertical ground reaction forces were determined using force plate data before and after surgery. Cranial drawer motion, tibial rotation, and varus-valgus motion were measured at monthly intervals. Radiographic, gross, and histological examinations of the stifle joints that had been operated on were performed 3 weeks, 4 months, and 10 months after surgery. A scoring system was used to evaluate lameness, osteophyte formation, and meniscal damage. Rank correlation coefficients were calculated between variables tested in pairs. Cranial drawer motion and abnormal tibial rotation were present in all of the joints that had been operated on. Peak vertical force and associated impulse were not restored during the study time period. Meniscal damage was noted in 25% of the dogs at month 4 and in 50% of the dogs at month 10. Progressive gross and histological deterioration of the articular cartilage was observed in all joints. Positive correlations were noted between the degree of stifle joint instability and meniscal injury or radiographic changes. FHT did not control cranial drawer motion and rotational instability, was not successful in restoring limb function, and did not prevent joint degeneration, especially meniscal damage.

Caudal cruciate ligament injury.

In small animals, CaCL injury occurs infrequently and is associated with isolated ruptures, attachment (bone) avulsions, or combined with multiple ligament injury of the stifle joint. Definitive diagnosis of CaCL usually requires direct examination of the stifle joint because detection of caudal drawer motion is confusing and may be masked by concurrent, possibly more significant lesions. Although the ligament is considered a primary stabilizer of the canine stifle joint, controversy exists regarding the need for surgical repair of CaCL injury. Although reattachment of avulsion injuries seems prudent, results of other stabilizing procedures for midsubstance tears have produced patients with minimal lameness and persistent drawer motion. Based on limited clinical and experimental data, it is conceivable that surgical stabilization of the CaCL-deficient stifle joint may not be necessary in small animals, although more clinical studies would be useful in conclusively delineating the role of this ligament.

A comparison of acute pull-out strength between two-way and one-way transfixation pin insertion for external skeletal fixation in canine bone.

This study tested the hypothesis that two-way insertion of an external skeletal fixator transfixation pin would weaken the pin-bone interface. Smooth and partially threaded (end) transfixation pins were placed in tibiae of 32 cadavers by slow speed drilling or hand placement through a predrilled pilot hole. In one bone of each tibial pair, pins were inserted 2 cm beyond the distal cortex and retracted to a predetermined position (two-way). In the contralateral limb, the pins were inserted in one forward motion to the predetermined position (one-way). The peak force (Newtons) required to extract the pins (pull-out strength) axially at a rate of 1 mm/sec was determined by using a universal testing machine. A significant (p < .05) decrease in pull-out strength was found in pins placed by two-way insertion (674 +/- 410) as opposed to one-way insertion (766 +/- 432). The results of this in vitro study suggest that one-way insertion should be used clinically to decrease weakening of the pin-bone interface and prevent possible failure of external fixators. A significantly greater pull-out strength was found for threaded pins placed in the proximal diaphysis (1459 +/- 330 Newtons) compared to the distal metaphysis (873 +/- 297 Newtons).

Bacterial isolates from blood cultures of dogs undergoing dentistry.

Bacteria in blood cultures in 30 dogs undergoing high-speed dental scaling and tooth extraction were examined. One or more positive blood cultures were identified in 9 of 30 (30%) dogs. Pasteurella spp. were most frequently (5 dogs) isolated and were sensitive to ampicillin, penicillin, cephalothin, chloramphenicol, tetracycline, amoxicillin with clavulanic acid, and sulfamethoxazole with trimethoprim. Two groups of 15 dogs each, anesthetized or sedated but not undergoing dental procedures, served as non-dentistry controls. There were no significant (p < .05) differences between the number of positive cultures in dentistry and non-dentistry groups. In healthy dogs undergoing high-speed dental scaling and tooth extraction, the occurrence of bacteria in blood cultures was much lower than previously reported. The clinical significance of positive blood cultures was uncertain.

Comparative thermoregulatory adaptations of field mice of the genus Apodemus to habitat challenges.

Thermoregulatory abilities, which may play a role in physiological adaptations, were compared between two field mouse species (Apodemus mystacinus and A. hermonensis) from Mount Hermon. While A. hermonensis is common at altitudes above 2100 m, A. mystacinus is common at 1650 m. The following variables were compared in mice acclimated to an ambient temperature of 24 degrees C with a photoperiod of 12L:12D, body temperature during exposure to 4 degrees C for 6 h, O2 consumption and body temperature at various ambient temperature, non-shivering thermogenesis measured as a response to a noradrenaline injection, and the daily rhythm of body temperature. Both species could regulate their body temperature at ambient temperatures between 6 and 34 degrees C. The thermoneutral zone for A. mystacinus lies between 28 and 32 degrees C, while for A. hermonensis a thermoneutral point is noted at 28 degrees C. Both species increased O2 consumption and body temperature as a response to noradrenalin. However, maximal VO2 consumption as an response to noradrenaline and non-shivering thermogenesis capacity were higher in A. mystacinus, even though A. hermonensis is half the size of A. mystacinus. The body temperature rhythm in A. hermonensis has a clear daily pattern, while A. mystacinus can be considered arhythmic. The results suggest that A. hermonensis is adapted to its environment by an increase in resting metabolic rate but also depends on behavioural thermoregulation. A. mystacinus depends more on an increased non-shivering thermogenesis capacity.

Surgical treatments for intervertebral disc disease.

Surgical treatments for intervertebral disc disease are useful for animals with gradually progressive, severely acute, or recurrent lesions. Surgical patients require a diligent neuroradiographic evaluation to confirm location and severity of the discopathy and rule out conditions unrelated to disc disease. Although controversial, some surgeons advocate fenestration for recurrent pain or mild ataxia associated with a noncompressive lesion. Decompressive procedures are recommended for treatment and prognostication of compressive disc-associated myelopathy. Foraminotomy is reserved for patients with lateralizing extrusions confirmed with myelography or newer imaging modalities (CT, MRI). Future treatments for animals may include chemonucleolysis or various discectomy procedures currently performed in humans with symptomatic disc disease.

Scintigraphic evaluation of tissue viability after gunshot injury in a dog.

Triple-phase bone scintigraphy was used to evaluate tissue viability in the forelimb of a dog after gunshot injury. This technique was reliable, noninvasive, and easily performed. It was used to complement radiography by providing functional, rather than structural, assessment of tissues on the basis of regional vascular patterns. In this dog, vascular impairment caused by trauma appeared as photopenic or "cold" spots during immediate (vascular), soft tissue and bone phases of the scintigraphic study. On the basis of gross morphologic and scintigraphic findings, forelimb amputation was performed.