To compare the influence of fluid on carboplatin elution, and assess the feasibility of ultrafiltration (UF) probe sampling
20 samples of 5 mg carboplatin in 1.0 mL 30% poloxamer 407 eluting in Dulbecco’s phosphate-buffered saline (DPBS) or canine plasma and 6 samples of UF probe sampling in 0.01 mg/mL carboplatin in DPBS or plasma.
Carboplatin-gel specimens in dialysis tubing (12- to 14-kDa pores) were placed in 100 mL of DPBS or canine plasma (37 °C and 600 rpm stirring) in a nonlidded and lidded experiment. Samples were collected in decreasing frequency for 96 hours. The 0.01-mg/mL carboplatin solutions in DPBS and plasma were sampled 6 times by UF probe (30-kDa pores) or direct aspiration. Platinum was measured using inductively coupled plasma mass spectrometry.
High fluid evaporation was noted in the nonlidded but not the lidded experiment. A burst release was seen in plasma (first 2 hours) and DPBS (first 5 hours) with the highest hourly increase in the first hour in both DPBS (6,040 ppb/h) and plasma (2,612 ppb/h), with no further increase after the first 22 hours. Platinum content in the specimens was higher at 96 hours than the surrounding fluid. Higher platinum concentrations were measured by both direct and UF probe sampling in DPBS than in plasma.
Platinum concentrations measured in DPBS were higher than in plasma, but elution patterns were similar. Ultrafiltration probes can be used to sample platinum in vitro and could be used in vivo to measure local unbound Pt tissue concentrations in local chemotherapy delivery.
To determine and compare the rate, pattern, and completeness of silver nanoparticle (AgNP) elution in vitro over 7 days from 3 carrier media in PBSS.
AgNPs in calcium sulfate hemihydrate (CSH) beads, poloxamer 407 gel, and a gelatin sponge.
Three carrier media were used to create constructs containing AgNPs (8,500 ng). All constructs were submerged in PBSS and stored at 38°C for 7 days. Samples were collected after 2, 6, 12, 18, 24, 36, 48, 72, 96, 120, 144, and 168 hours, and AgNP concentration was measured with inductively coupled plasma mass spectrometry. Constructs were tested in quadruplicate.
Sustained release of AgNPs was seen from all constructs for a minimum of 72 hours. Release from all constructs was incomplete, with an initial burst during the first 24 hours followed by a time-dependent decrease in elution rate for up to 168 hours. A mixed-effects model showed a significant difference in AgNP release over time (P < .001) and among media (P < .001). AgNP–gel constructs released the largest quantity of AgNPs (8,401.02 ng [98.84%]), followed by AgNP–sponge constructs (1,503.45 ng [17.69%]). Release from AgNP–CSH bead constructs was 87.824 ng (1.03%), with no additional release after 72 hours.
Sustained release of AgNPs is possible in vitro, but efficacy against bacterial infections needs to be investigated prior to clinical use.
Objective—To compare preplanned lateral surgical margins and measured lateral histologic margins for cutaneous and subcutaneous mast cell tumor (MCT) resections in dogs.
Design—Retrospective case series.
Sample—51 biopsy specimens from dogs (n = 46) with MCTs.
Procedures—All canine patients that underwent curative-intent surgical resection of cutaneous or subcutaneous MCTs from January 1, 2010, through June 30, 2013, with complete medical records including signalment, body condition score (BCS), surgery report (with measured surgical margins), and histopathology report were included. The surgically measured tumor margins in each quadrant were grouped and compared with the corresponding histologic margins. Specimens from dogs with truncal MCTs and a BCS of 7 to 9 on a scale from 1 to 9 (ie, high) were compared with those of dogs with a BCS of 4 to 6 to evaluate effect of BCS on tissue margins.
Results—51 specimens were included. Surgically mapped lateral margins differed significantly from histologically reported margins in all 4 quadrants. The mean histologic margins were 35% to 42% smaller than the surgical margins for the combined 51 specimens. A higher BCS did not significantly influence the magnitude of the decrease in lateral margins measured histologically. No significant difference was found for the magnitude of the differences between any of the 4 lateral margins.
Conclusions and Clinical Relevance—Results of this study suggested that surgical and histologic margins may differ significantly for canine cutaneous and subcutaneous MCTs. This may be a result of tissue shrinkage following excision and fixation, extension of the MCT beyond palpable margins, or both. Histologic measurements may significantly underestimate the tumor-free margins in dogs with cutaneous and subcutaneous MCTs. (J Am Vet Med Assoc 2015;247:184–189)
OBJECTIVE To evaluate the feasibility of manufacturing gastrojejunostomy tubes from jejunostomy and gastrostomy tubes that would allow for gastric and enteral feeding of and aspiration of gastric contents from small animal patients.
DESIGN In vitro study.
SAMPLE 9 gastrojejunostomy constructs.
PROCEDURES Commercially available gastrostomy and jejunostomy tubes were combined to create 9 constructs. Three investigators tested each construct with 4 solutions (tap water, a commercial enteral diet, and 2 canned food–water mixtures) and 3 syringe sizes for ease of injection through the gastrostomy and jejunostomy tubes and aspiration through the gastrostomy tube. Flow rates were calculated and analyzed to evaluate effects of tube diameter and syringe size for each solution.
RESULTS The 20F/8F, 24F/8F, 28F/8F, and 28F/10F (gastrostomy tube/jejunostomy tube) constructs allowed for injection and aspiration of all solutions. The 5F jejunostomy tubes allowed only water to be injected, whereas the 8F jejunostomy tubes did not allow injection of the canned food–water mixtures. The 20F/10F construct did not allow injection or aspiration through the gastrostomy tube, whereas the 18F/8F construct allowed injection but not aspiration through the gastrostomy tube. Faster flow rates through the gastrostomy tube were associated with larger gastrostomy tube diameter, smaller jejunostomy tube diameter, and smaller syringe size. Faster flow rates through the jejunostomy tube were associated with smaller jejunostomy tube diameter.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that homemade gastrojejunostomy constructs would allow for administration of a variety of enteral diets. Limitations to the administration and aspiration of various enteral diets as well as patient needs should be considered before a gastrojejunostomy tube combination is chosen.
Objective—To evaluate fracture healing after minimally invasive plate osteosynthesis (MIPO) or open reduction and internal fixation (ORIF) of coexisting radius and ulna fractures in dogs via ultrasonography and radiography.
Design—Prospective cohort study.
Animals—16 dogs with radius-ulna fractures that underwent MIPO (n = 9; 2 dogs were subsequently not included in the analyses because of incomplete follow-up information) or ORIF (7).
Procedures—Dogs in the 2 treatment groups were matched by age, body weight, and configuration of the fractures. Fracture healing was evaluated with ultrasonography, power Doppler ultrasonography, and radiography every 3 to 4 weeks until healing was complete; a semiquantitative score based on the number of Doppler signals was used to characterize neovascularization, and subjective B-mode ultrasonographic and radiographic scores were assigned to classify healing.
Results—Fractures in dogs that underwent MIPO healed in significantly less time than did fractures in dogs that underwent ORIF (mean ± SD; 30 ± 10.5 days and 64 ± 10.1 days, respectively). Radiography revealed that fractures in dogs that underwent MIPO healed with significantly more callus formation than did fractures in dogs that underwent ORIF. Although Doppler ultrasonography revealed abundant vascularization in fractures that were healing following MIPO, no significant difference in neovascularization scores was found between groups.
Conclusions and Clinical Relevance—For dogs with radius-ulna fractures, data indicated that bridging osteosynthesis combined with a minimally invasive approach contributed to rapid healing after MIPO. The MIPO technique may offer some clinical advantage over ORIF, given that complete radius-ulna fracture healing was achieved in a shorter time with MIPO.
Case Description—A 5.5-month-old female domestic longhair cat was examined because of dorsal deviation of the caudal aspect of the sternum and progressively worsening dyspnea during play activities.
Clinical Findings—A diagnosis of pectus excavatum was made clinically and confirmed radiographically. The cardiac silhouette was shifted into the right hemithorax. The vertebral index (VI) and frontosagittal index (FSI), which are radiographic indices used to grade the extent of the deformity, were 5.2 and 3.0, respectively. Minimum thoracic height was 13 mm at this time.
Treatment and Outcome—The sternal malposition was corrected during surgery; for stabilization, an internal splint was provided by use of a plate that was applied to the ventral side of the sternum. Radiographic indices improved until day 85; at that time, an increase in the distance between plate and sternum was detected, and plate removal was advised. The radiographic indices improved again after plate removal. At 310 days after surgery, VI was 9.6, FSI was 1.6, and minimum thoracic height was 34 mm. No dyspnea was evident during physical examination.
Clinical Relevance—Results of treatment suggest that this technique may be useful as an alternative surgical option for cats with pectus excavatum that have a noncompliant sternum.
Objective—To investigate the use of ultrasonography to assess nonunion of fractures in dogs and to compare results of ultrasonography, radiography, and histologic examination.
Sample Population—8 nonunion fractures in 6 dogs (1 each in 5 dogs and 3 in 1 dog); dogs ranged from 7 to 94 months of age and weighed 6 to 30 kg.
Procedures—Diagnostic assessment consisted of complete clinical and orthopedic examinations, radiography, B-mode (brightness mode) ultrasonography, and power Doppler ultrasonography. Biopsy samples were obtained during surgery for histologic examination. They were stained with H&E and immunolabeled by use of anti-CD31 antibodies. Correlations of power Doppler score, power Doppler count, vessel area, and radiographic prediction with the mean number of vessels counted per hpf were derived.
Results—Radiographically, 7 of 8 nonunion fractures were diagnosed as atrophic and were therefore estimated to be nonviable. Vascularity of nonunion fractures during power Doppler ultrasonography ranged from nonvascularized to highly vascularized. Absolute vessel count during histologic examination ranged from 0 to 63 vessels/hpf; 5 nonunion sites had a mean count of > 10 vessels/hpf. Vascularity during power Doppler ultrasonography was highly correlated with the number of vessels per hpf, whereas the correlation between the radiographic assessment and histologic evaluation was low.
Conclusions and Clinical Relevance—Radiographic prediction of the viability of nonunion fractures underestimated the histologically assessed vascularity of the tissue. Power Doppler ultrasonography provided a more accurate estimation of the viability of the tissue and therefore the necessity for debridement and autografts during revision surgery.
OBJECTIVE To compare pursestring, Witzel (seromuscular inversion), and seromuscular incision jejunostomy tube placement techniques in vitro.
SAMPLE Jejunal specimens from 10 dogs.
PROCEDURES Jejunal segments (50 cm) were harvested immediately prior to euthanasia from 10 mixed-breed dogs Specimens were harvested with the orad and aborad ends clamped and stored in saline (0.9% NaCl) solution–soaked towels during instrumentation. Three jejunostomy tubes were placed via 3 techniques (pursestring, Witzel, and seromuscular incision), and 2 double lumen central venous catheters were placed at each intestinal end for luminal filling and leak testing. Intestinal luminal area was measured ultrasonographically with specimens suspended in a warm undyed saline solution bath with the intestinal lumen filled with dyed saline solution (intraluminal pressure, 6 mm Hg). Leak testing was performed by means of infusion of dyed saline solution (4 mL/min) until each jejunostomy site failed. Intestinal luminal area and leakage pressure were compared between the 3 tube placement techniques.
RESULTS The Witzel and seromuscular incision techniques decreased the intestinal luminal area measured at the tube insertion site, albeit nonsignificantly. For the seromuscular incision technique, a significant decrease in intestinal luminal area at the intraluminal site of measurement was found. For 2/30 specimens (1/10 pursestring and 1/10 seromuscular incision), failure occurred at pressures within the range of previously reported peak peristaltic pressure for dogs. Failure occurred at supraphysiologic peristaltic pressures for the remaining 28 specimens, including all 10 specimens for the Witzel technique.
CONCLUSIONS AND CLINICAL RELEVANCE In this in vitro study, all specimens for the Witzel technique withstood physiologic peristaltic pressures during leak testing. Both tunneling techniques (Witzel and seromuscular incision) created a decrease in intestinal luminal area. Further investigation, including in vivo testing, is indicated to evaluate the clinical relevance of these findings.
OBJECTIVE To investigate in vitro carboplatin release from 6 carrier media.
SAMPLE 6 carboplatin-containing carrier media.
PROCEDURES An in vitro release study was performed with 6 commercially available carrier media: a hemostatic gelatin sponge, a poloxamer copolymer gel, and 2 sizes (3 and 4.8 mm in diameter) of beads molded from each of 2 commercial calcium sulfate products. All carrier media contained 10 mg of carboplatin. Carrier media specimens were placed in 37°C PBS solution for 96 hours. Carboplatin concentrations in PBS solution were measured by use of high-performance liquid chromatography at 15 time points to calculate the amount and proportion of carboplatin released from each specimen.
RESULTS Peak release of carboplatin from the poloxamer copolymer gel and hemostatic gelatin sponge were achieved after 4 and 20 hours, respectively. Maximum release did not differ significantly between the poloxamer copolymer gel and hemostatic gelatin sponge, but both released significantly more carboplatin within 96 hours than did both of the commercial calcium sulfate products. The poloxamer copolymer gel released 99% of the carboplatin, and the hemostatic gelatin sponge released 68.5% of the carboplatin. Peak release of carboplatin from the calcium sulfate beads was not reached within 96 hours.
CONCLUSIONS AND CLINICAL RELEVANCE In this study, carboplatin release from the hemostatic gelatin sponge was incomplete. The poloxamer copolymer gel and hemostatic gelatin sponge released carboplatin rapidly in vitro, whereas calcium sulfate beads did not.
Objective—To evaluate postmortem surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomies.
Animals—10 healthy mixed-breed male dogs.
Procedures—Dogs were anesthetized, and 5 surgical techniques (pretied suture loop, energy-based sealer-divider, harmonic scalpel, suction with clip application, or suction with use of a thoracoabdominal stapler) were used to perform 5 partial liver lobectomies in each dog. Dogs were euthanatized, and the portal vein and hepatic artery were cannulated and perfused with a modified kidney perfusion machine (pulsatile flow for arterial perfusion and nonpulsatile flow for portal perfusion). Lobectomy sites were inspected for leakage of perfusate, and time until detection of leakage was recorded. The techniques in each dog were ranked on the basis of time until leakage. Time until leakage and rankings for each surgical technique were analyzed by use of an ANOVA.
Results—Leakage of perfusate was recorded in 44 lobes at supraphysiologic pressures. Of the 6 lobes without leakage, a pretied suture loop procedure was performed in 5 and a harmonic scalpel procedure was performed in 1. Time until leakage and the ranking differed significantly between the pretied suture loop and the other techniques. Time until leakage and ranking did not differ significantly among the other techniques.
Conclusions and Clinical Relevance—Time until leakage of perfusate was greater for the pretied suture loop technique than for the other techniques, and that technique did not fail in 5 of 10 lobes. However, all techniques appeared to be safe for clinical use.