Evaluation of automated staple sizes on gastric layer incorporation and intraluminal pressure for partial gastrectomy closure in an ex vivo canine model.

OBJECTIVE: To evaluate the performance of automated staple sizes on a cadaveric canine partial gastrectomy model. METHODS: Stomachs were transected through the gastric body axis and randomly allocated to two closure groups: Group B, thoracoabdominal (TA) stapler 3.5 mm staple cartridge (blue); Group G, TA stapler 4.8 mm staple cartridge (green). After construct completion, leak testing was performed for both groups and compared. Initial leakage pressure (ILP), maximal leakage pressure (MLP) and leakage location were recorded. Staple lines were evaluated by direct observation and fluoroscopy to assess sub-mucosal layer incorporation and staple conformation. Staple shape was classified as optimal or suboptimal. Significance was set at p less than 0.5. RESULTS: Following gastrectomy, the mean double gastric wall thickness was 7.82 ± 2.05 mm at the gastric body. Mean ILP was significantly lower in groups G (17.13 ± 1.19 mmHg) compared to group B (50.46 ± 6.03 mmHg, p = 0.0013). Similarly, mean MLP was significantly lower in group G (21.41 ± 1.39 mmHg) compared to group B (64.61 ± 10.21 mmHg, p < 0.0001). Although group G had higher percentage of B-shaped staple formation compared to group B, this was not significant (group G; 92.38%, group B; 54.56%; p = 0.054). CONCLUSION: The 3.5 mm TA staple cartridge (blue) achieved superior bursting pressures compared with the 4.8 mm TA staple cartridge (blue) for the closure of a canine partial gastrectomy model. Both staple sizes incorporated all gastric layers. No differences were noticed in optimal staple conformation between groups. In vivo investigation is warranted to evaluate the use of different staple sizes on gastric tissue perfusion, successful healing and post-operative stasis and dehiscence.

Adrenal tumors treated by adrenalectomy following spontaneous rupture carry an overall favorable prognosis: retrospective evaluation of outcomes in 59 dogs and 3 cats (2000-2021).

OBJECTIVE: To conduct a retrospective multi-institutional study reporting short- and long-term outcomes of adrenalectomy in patients presenting with acute hemorrhage secondary to spontaneous adrenal rupture. ANIMALS: 59 dogs and 3 cats. METHODS: Medical records of dogs and cats undergoing adrenalectomy between 2000 and 2021 for ruptured adrenal masses were reviewed. Data collected included clinical presentation, preoperative diagnostics, surgical report, anesthesia and hospitalization findings, histopathology, adjuvant treatments, and long-term outcome (recurrence, metastasis, and survival). RESULTS: Median time from hospital admission to surgery was 3 days, with 34% of surgeries being performed emergently (within 1 day of presentation). Need for intraoperative blood transfusion was significantly associated with emergent surgery and presence of active intraoperative hemorrhage. The short-term (≤ 14 days) complication and mortality rates were 42% and 21%, respectively. Negative prognostic factors for short-term survival included emergent surgery, intraoperative hypotension, and performing additional surgical procedures. Diagnoses included adrenocortical neoplasia (malignant [41%], benign [12%], and undetermined [5%]), pheochromocytoma (38%), a single case of adrenal fibrosis and hemorrhage (2%), and a single case of hemangiosarcoma (2%). Local recurrence and metastasis of adrenocortical carcinoma were confirmed in 1 and 3 cases, respectively. Overall median survival time was 574 days and 900 days when short-term mortality was censored. No significant relationship was found between histopathological diagnosis and survival. CLINICAL RELEVANCE: Adrenalectomy for ruptured adrenal gland masses was associated with similar short- and long-term outcomes as compared with previously reported nonruptured cases. If hemodynamic stability can be achieved, delaying surgery and limiting additional procedures appear indicated to optimize short-term survival.

Laparoscopic ultrasonography of the liver is feasible and safe in dogs.

OBJECTIVE: To describe the feasibility and technique for performing laparoscopic ultrasound (LUS) of the liver in dogs. ANIMALS: 12 client-owned dogs presenting for elective laparoscopic surgery from January 1, 2022, to October 31, 2022. METHODS: Laparoscopic exploration and LUS of the liver were performed in all dogs. Dogs were positioned in reverse Trendelenburg and laterally rotated to facilitate access to all liver lobes. Time to perform laparoscopic exploration and LUS, ability to visualize and access each liver lobe entirely, and any complications were recorded. Each dog underwent an elective laparoscopic procedure. The surgeon completed a National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire after surgery. RESULTS: Mean body weight was 25.9 kg (SD, ± 4.1 kg; range, 5.7 to 62 kg). All liver lobes were scanned to the level of the hilus in 10/12 dogs. In 2 dogs, the caudate lobe could not be completely imaged. Median time to perform LUS was 9 minutes (IQR, 5 to 16.5 minutes), and median NASA-TLX score was 9/100 (IQR, 6.3 to 20). There was a significantly strong negative correlation between time to perform LUS (r = -0.77; P = .0037) and NASA-TLX score (r = -0.84; P = .0006) with trial number. Minor complications occurred in 2 dogs during laparoscopic exploration. No complications occurred during LUS. CLINICAL RELEVANCE: LUS was feasible and safe in all dogs. The right lateral and caudate lobes were occasionally challenging to access. Technical demand and time to perform LUS improved with experience, suggesting a learning curve. Evaluation of LUS in dogs with clinical disease is warranted.

Biomechanical comparison of canine median sternotomy closure using suture tape and orthopedic wire cerclage.

OBJECTIVE: To compare the mechanical properties of suture tape and orthopedic wire cerclage in an ex vivo canine median sternotomy model. STUDY DESIGN: Ex vivo. ANIMALS: Twelve large-breed canine cadaveric sternums. METHODS: Median sternotomies were performed, leaving the manubrium intact. The specimens were randomly assigned to group W (20-gauge stainless steel orthopedic wire cerclage in a figure-of-eight pattern) or group ST (suture tape in a figure-of-eight pattern). Each specimen was laterally distracted until failure using an electrodynamic materials-testing system. RESULTS: No differences were observed for displacement, yield load, maximum load, implant failure between the groups. The orthopedic wire construct was stiffer than the suture tape construct. CONCLUSION: Suture tape was biomechanically similar to orthopedic wire cerclage for sternotomy closure in dogs, although wire constructs were stiffer. CLINICAL SIGNIFICANCE: Suture tape may represent an alternative to cerclage wire for sternotomy closure in dogs. Additional studies evaluating its clinical use are needed.

Geometric, landmark-guided technique reduces tissue trauma, surgery time, and subjective difficulty for canine peripheral lymphadenectomies: an educational crossover study.

OBJECTIVE: To compare the effect of a geometric, landmark-guided lymphadenectomy (LL) approach to peripheral lymph nodes (LNs) on successful LN identification, surgical time, tissue trauma, and ease of LN identification compared to standard lymphadenectomy (SL) and methylene blue-guided lymphadenectomy (MBL). SAMPLE: 18 adult, mixed-breed canine cadavers operated on by 7 veterinarians and 5 fourth-year veterinary students between July 23 and October 12, 2022. METHODS: Participants were provided standardized, publicly available materials regarding the anatomy and surgical techniques for SL of 3 peripheral lymphocentrums: superficial cervical, axillary (ALN), and superficial inguinal (SILN). Participants performed the 3 SLs unilaterally on canine cadavers. Thereafter, they were randomly assigned to 2 crossover groups: MBL and LL. All dissections were separated by at least 2 weeks for each participant. Primary outcome measures included successful LN identification, surgical time, tissue trauma scores, and subjective difficulty. RESULTS: Successful LN identification was highest with LL (86%) compared to SL (69%) and MBL (67%). Subjective difficulty scores were reduced with LL for SILN dissections. Tissue trauma scores were reduced when using LL for ALN and SILN compared to MBL and SL. Time to LN identification was reduced for ALN with LL. No significant differences were observed between MBL and SL, or for the superficial cervical dissections. CLINICAL RELEVANCE: Peripheral lymphadenectomies are time consuming and difficult for veterinarians in early stages of surgical training. Little surgical guidance is provided within current literature. Geometric, landmark-guided lymphadenectomies may improve LN identification success and reduce surgical time, tissue trauma, and procedure difficulty, which could encourage their clinical application.

Multiple biliary duct hamartomas in a cat resulting in a hepatic mass: A case report.

A 13-year-old, male neutered domestic short-haired cat was diagnosed with multiple biliary duct hamartomas after liver lobectomy for a suspected malignant hepatic mass. Distinguishing ultrasonographic findings included a lobular, mostly well-defined, heterogeneous, predominantly hyperechoic, left hepatic mass. Computed tomography (CT) confirmed the presence of a lobular, well-defined, fluid to soft tissue attenuating, heterogeneously hypoenhancing left divisional hepatic mass. Grossly, a large left sided multilobular pale pink gelatinous hepatic mass was surgically excised. Histopathologically, the mass was composed of irregular cystic spaces lined by cuboidal epithelium and separated by mature regular fibrous tissue. Three months following surgery there was no evidence of recurrence or progression of disease on repeat abdominal ultrasound (AUS).

Acellular fish skin may be used to facilitate wound healing following wide surgical tumor excision in dogs: a prospective case series.

OBJECTIVE: To prospectively evaluate clinical outcomes using acellular fish skin grafts (FSGs) for the management of complete wound healing by secondary intention after wide surgical excision of skin tumors in dogs. ANIMALS: 5 dogs undergoing wide surgical excision of skin tumors on the distal extremity. CLINICAL PRESENTATION AND PROCEDURES: FSGs were applied to surgical wound beds following wide excision of the tumor. Bandages were changed weekly and additional grafts placed when integration of the previous graft was complete. The wounds were assessed for the following: dimensions, tissue health (color), time to complete epithelialization, complications, and tumor recurrence. RESULTS: All masses were excised with 2-cm lateral margins and 1 fascial plane deep to the tumor. Tumor diagnoses included 3 mast cell tumors and 2 soft tissue sarcomas. Surgical wounds had a median area of 27.6 cm2 (range, 17.6 to 58.7 cm2). The median number of FSG applications was 5 (range, 4 to 9 applications). Complete epithelialization occurred within 7 to 9 weeks for uncomplicated wounds (3 of 5) and 12 to 15 weeks for complicated wounds (2 of 5) that sustained self-trauma. There were no adverse events related to the use of FSGs. Local recurrence was not seen over a follow-up period ranging from 239 to 856 days. CLINICAL RELEVANCE: Wide surgical excision of distal extremity skin tumors, followed by repeated application of acellular FSGs, resulted in complete healing of all wounds with no adverse events. This treatment method does not require advanced reconstructive surgical skills and may be useful for the management of skin tumors on the distal extremities.

Client perceptions improve with collaborative care when managing dogs with cancer: a Collaborative Care Coalition study.

OBJECTIVE: Collaboration between primary care veterinarians (pcVets) and veterinary oncologists is common for dogs diagnosed with cancer, but no data exist that explore dog owner utilization and perceptions of collaborative care. The objectives were to describe dog owner perceptions of the value of collaborative veterinary cancer care and identify drivers of a positive collaborative care experience between the pcVet and oncologic specialists. SAMPLE: 890 US dog owners who had pets diagnosed with cancer in the past 3 years. PROCEDURES: Online contextual survey. Data were analyzed using group comparisons and multiple regression analysis. Significance was set at P < .05. RESULTS: 76% of clients sought specialty care following cancer diagnosis in their dog. Seventy percent of owners across all income brackets indicated that referral to a specialist was a very good value based on money spent and outcomes. Delayed referral resulted in lower client satisfaction scores for pcVets. Top predictors of client satisfaction with pcVets were as follows: responsiveness to questions, staying involved with their dog's care, and willingness to work with other veterinarians and specialists. For specialists, top predictors were as follows: providing accurate cost estimates, cancer knowledge, and effectiveness of care. Client perceptions of pcVets were 6 times more likely to improve following referral to a specialist. All were significant predictors of owner advocacy (P < .0001). CLINICAL RELEVANCE: Dog owners perceived early collaboration between pcVets and specialists favorably, fostering client satisfaction and positive perceptions of the value for service provided for dogs diagnosed with cancer.

A narrative review on the role of carbon nanoparticles in oncology.

The lymphatic system is the first site of metastasis for most tumors and is a common reason for the failure of cancer therapy. The lymphatic system's anatomical properties make it difficult to deliver chemotherapy agents at therapeutic concentrations while avoiding systemic toxicity. Carbon nanoparticles offer a promising alternative for identifying and transporting therapeutic molecules. The larger diameter of lymphatic vessels compared to the diameter of blood vessels, allows carbon nanoparticles to selectively enter the lymphatic system once administered subcutaneously. Carbon nanoparticles stain tumor-draining lymph nodes black following intratumoral injection, making them useful in sentinel lymph node mapping. Drug-loaded carbon nanoparticles allow higher concentrations of chemotherapeutics to accumulate in regional lymph nodes while decreasing plasma drug accumulation. The use of carbon nanoparticles for chemotherapy delivery has been associated with lower mortality, fewer histopathology changes in vital organs, and lower serum concentrations of hepatocellular enzymes. This review will focus on the ability of carbon nanoparticles to target the lymphatics as well as their current and potential applications in sentinel lymph node mapping and oncology treatment regimens. This article is categorized under: Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery.

Complications associated with iliosacral lymphadenectomy in dogs with metastatic apocrine gland anal sac adenocarcinoma.

Objective: To report intraoperative and immediate postoperative complications associated with removal of metastatic iliosacral lymph nodes in dogs with apocrine gland anal sac adenocarcinoma. Animals: There were 136 client-owned dogs in the study. Procedure: Retrospective multi-institutional study. The database of collaborating institutions was searched for dogs with metastatic apocrine gland anal sac adenocarcinoma that underwent lymphadenectomy for removal of one or more iliosacral lymph nodes. Information of signalment, hematological abnormalities, abdominal computed tomography or ultrasound findings, number and size of enlarged lymph nodes, intraoperative and postoperative complications, treatment and outcome were collected. Results: The overall complication rate associated with metastatic iliosacral lymphadenectomy was 26.1%. The only intraoperative complication recorded was hemorrhage and was reported in 24 (17.6%) surgeries, 11 (45.8%) of which received a blood transfusion. Postoperative complications were reported in 10.4% of surgeries, and included edema formation (n = 4, 2.6%), unilateral or bilateral paraparesis (n = 4, 2.6%), hypotension (n = 3, 2.0%), surgical site infection (n = 2, 1.3%), abdominal incision dehiscence (n = 1, 0.6%), urinary incontinence (n = 1, 0.6%), and death (n = 1, 0.6%). The size of the iliosacral lymph nodes was significantly associated with a greater risk of complications, hemorrhage, and the need of transfusion during lymphadenectomy for metastatic apocrine gland anal sac adenocarcinoma. Conclusion: Complications associated with iliosacral lymphadenectomy for metastatic apocrine gland anal sac adenocarcinoma are relatively common and mostly relate to hemorrhage. These complications are significantly associated with the size of the extirpated metastatic lymph nodes. Clinical relevance: This retrospective study provides information for the clinician regarding the potential surgical complications for extirpation of metastatic iliosacral lymph nodes. These complications, although not common, can be severe and should be discussed with owners before surgery.

Objectif: Rapporter les complications peropératoires et postopératoires immédiates associées à l'ablation des ganglions lymphatiques ilio-sacrés métastatiques chez les chiens atteints d'un adénocarcinome des glandes apocrines des sacs anaux. Animaux: Il y avait 136 chiens appartenant à des clients dans l'étude. Procédure: Étude multi-institutionnelle rétrospective. La base de données des institutions collaboratrices a été recherchée pour les chiens atteints d'un adénocarcinome métastatique des glandes apocrines des sacs anaux qui ont subi une lymphadénectomie pour l'ablation d'un ou plusieurs ganglions lymphatiques ilio-sacrés. Des informations sur le signalement, les anomalies hématologiques, les résultats de la tomodensitométrie abdominale ou de l'échographie, le nombre et la taille des ganglions élargis, les complications peropératoires et postopératoires, le traitement et les résultats ont été recueillis. Résultats: Le taux global de complications associées à la lymphadénectomie ilio-sacrée métastatique était de 26,1 %. La seule complication peropératoire enregistrée était une hémorragie et a été rapportée dans 24 (17,6 %) chirurgies, dont 11 (45,8 %) ont reçu une transfusion sanguine. Des complications postopératoires ont été signalées dans 10,4 % des interventions chirurgicales et comprenaient la formation d'oedème (n = 4, 2,6 %), la paraparésie unilatérale ou bilatérale (n = 4, 2,6 %), l'hypotension (n = 3, 2,0 %), l'infection du site opératoire (n = 2, 1,3 %), la déhiscence de l'incision abdominale (n = 1, 0,6 %), l'incontinence urinaire (n = 1, 0,6 %) et le décès (n = 1, 0,6 %). La taille des ganglions ilio-sacrés était significativement associée à un risque accru de complications, d'hémorragie et à la nécessité d'une transfusion lors d'une lymphadénectomie pour un adénocarcinome métastatique des glandes apocrines des sacs anaux. Conclusion: Les complications associées à la lymphadénectomie ilio-sacrée pour l'adénocarcinome métastatique des glandes apocrines des sacs anaux sont relativement fréquentes et concernent principalement l'hémorragie. Ces complications sont significativement associées à la taille des ganglions lymphatiques métastatiques retirés. Pertinence clinique: Cette étude rétrospective fournit des informations au clinicien concernant les complications chirurgicales potentielles pour le retrait des ganglions lymphatiques ilio-sacrés métastatiques. Ces complications, bien que rares, peuvent être graves et doivent être discutées avec les propriétaires avant la chirurgie.(Traduit par Dr Serge Messier).

Clinical outcomes of thyroid tumours with concurrent epithelial and mesenchymal components in 14 dogs (2006-2020).

BACKGROUND: While rare, multiple individual case reports have described mixed thyroid tumours in dogs containing both epithelial and mesenchymal neoplastic components. OBJECTIVES: In this retrospective case series, we describe the clinical presentation, treatment and outcome of 14 dogs of canine thyroid tumours with concurrent mesenchymal and epithelial neoplastic populations. METHODS: Fourteen cases were retrospectively abstracted from nine institutions. Histopathologic samples and reports were collected from 10/14 dogs and reviewed by a single board-certified anatomic pathologist. RESULTS: All 14 dogs had curative-intent surgery to remove the thyroid neoplasm. The most common surgery performed was a unilateral thyroidectomy (10/14 dogs). Postoperatively, systemic therapy was administered in eight dogs. Six dogs developed local recurrence with a median time to loco-regional recurrence of 53 days. Ten dogs developed metastatic disease with the most common metastatic site being the lungs (6/10 dogs), with a median time to metastasis of 93 days. Ten dogs were euthanised due to locoregional or distant progression of their mixed thyroid neoplasm. The overall median survival time was 156 days (95%CI: 49-244). The median survival time for dogs treated with adjuvant therapy was 189 days (95%CI: 24-244), whereas dogs without adjuvant therapy had a median survival time of 156 days (95%CI: 35-upper limit could not be calculated; p = 0.62). CONCLUSION: The thyroid tumours with both mesenchymal and epithelial components in this small sample set were associated with a poor prognosis after surgical excision with or without adjunctive therapy.

Outcomes of dogs undergoing immediate or delayed surgical treatment for gastrointestinal foreign body obstruction: A retrospective study by the Society of Veterinary Soft Tissue Surgery.

OBJECTIVE: To evaluate gastrointestinal injury and outcomes between dogs treated with immediate surgical intervention vs those treated with delayed surgical intervention for gastrointestinal foreign body obstruction (GIFBO). STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: Client-owned dogs (n = 855) from five referral hospitals. METHODS: Medical records of dogs in which GIFBO had been diagnosed between 2007 and 2017 were reviewed for preoperative management, timing of surgery, intraoperative findings, postoperative management, outcome, and survival. Surgical intervention was classified as immediate when it occurred within 6 hours of presentation and delayed when it occurred >6 hours after presentation. RESULTS: Outcomes did not differ between dogs treated immediately (n = 584) or over 6 hours after presentation (n = 210). Intestinal necrosis and perforations were more common when surgery was delayed (P = .008; P = .019) but became nonsignificant after controlling for preoperative differences. Risk factors for necrosis and perforations included duration of clinical signs, increased lactate, linear foreign material, and timing of surgery. Enterectomies (P = .004) as well as the duration of surgery (P = .004) and anesthesia (P = .001) were increased when surgery was delayed. Immediate surgery was associated with earlier return to feeding (P = .004) and discharge from the hospital (P < .001); (5%) dogs in each group (n = 33 immediate; n = 11 delayed) either had a negative explore or the foreign body was milked aborally into the colon at the time of surgery. CONCLUSION: Although outcomes were not associated with surgical timing, the unadjusted prevalence of gastrointestinal injury and, thus, the requirement for complex surgical procedures was higher in the delayed group. CLINICAL SIGNIFICANCE: Earlier surgical treatment of stabilized dogs with GIFBO may involve fewer complex procedures and accelerate recovery.

Pharmacokinetics of platinum and safety evaluation of carboplatin-impregnated calcium sulfate hemihydrate beads after implantation in healthy cats.

OBJECTIVE: To evaluate the pharmacokinetics (PK) of platinum (Pt) and safety of carboplatin-impregnated calcium sulfate hemihydrate (C-I CSH) beads after implantation in healthy cats. STUDY DESIGN: In vivo experimental study. ANIMALS: Six healthy adult cats. METHODS: Three C-I CSH beads were implanted in muscle pockets over the right and left hemithoraces of each cat (~3.9 mg/kg of Pt; 60.4 mg/m2 of calculated carboplatin). Hematology and blood chemistry were tested at baseline and 3, 7, 14, and 21 days postimplantation. Serum was analyzed for Pt at specific times from 1 hour to 21 days. Tissue was obtained for histopathology and analysis of Pt at 3, 7, 14, and 21 days at standardized distances from implantation sites. RESULTS: Platinum was detected in tissues at all times and distances (range, 0.1-4.19 µg/g). Serum Pt increased up to 2.6 hours (3.25 µg/mL) then decreased sharply. Samples containing muscle had higher Pt compared with samples without muscle (P = .004). Mild hypercalcemia was noted in four cats, and mild inflammatory reaction was noted on histopathology of all samples. CONCLUSION: Platinum was released from C-I CSH beads differentially into surrounding tissues over 21 days. Systemic absorption of Pt was minimal, but mild hypercalcemia occurred. CLINICAL SIGNIFICANCE: Implantation was well tolerated by healthy adult cats. Securing beads within muscle may limit Pt diffusion to targeted tissue. Although Pt concentrations did not achieve levels reported to be cytotoxic for feline sarcoma cells in culture, results provide evidence to support evaluation of efficacy in the tumor microenvironment of cats with locally invasive cancers.

Jejunocystoplasty and Bilateral Ureteral Reimplantation in a Dog Following Total Cystectomy.

A 6 yr old Boston terrier presented with acute onset of vomiting and anuria 4 days following a caesarian section and ovariohysterectomy for treatment of dystocia. A total cystectomy with ligation of both ureters was diagnosed via exploratory laparotomy surgery. A jejunocystoplasty was performed in addition to a bilateral reimplantation of the ureters into the reconstructed bladder and proximal urethra. Postoperative complications included a retained ureteral stent, persistent pyelectasia, persistent hydroureters, recurrent urinary tract infections, and intermittent urinary incontinence. Four years postoperation, the dog is doing clinically well with intermittent urinary incontinence and periodic urinary tract infections. Jejunocystoplasty with bilateral ureteral reimplantation should be considered as a treatment option for dogs following total cystectomy that occurred because of a surgical error. Owners should be informed of potential complications prior to surgery.

Simulation of spatial diffusion of platinum from carboplatin-impregnated calcium sulfate hemihydrate beads by use of an agarose gelatin tissue phantom.

OBJECTIVE To characterize spatial release of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads by use of an agarose tissue phantom. SAMPLE 3-mm-diameter beads (n = 60) containing 4.6 mg of carboplatin (2.4 mg of platinum)/bead. PROCEDURES 18 L of 1% agarose was prepared and poured into 36 containers (10 × 10 × 10 cm), each of which was filled half full (0.5 L/container). After the agarose solidified, 1, 3, 6, or 10 CI-CSH beads were placed on the agar in defined patterns. An additional 36 blocks of agar (0.5 L/block) were placed atop the beads, positioning the beads in the center of 1 L of agar. The experiment was replicated 3 times for each bead pattern for 24, 48, and 72 hours. At these times, representative agarose blocks were sectioned in the x-, y-, and z-planes and labeled in accordance with their positions in shells radiating 1, 2, 3, 4, and 5 cm from the center of the blocks. Agarose from each shell was homogenized, and a sample was submitted for platinum analysis by use of inductively coupled plasma-mass spectroscopy. RESULTS Platinum diffused from CI-CSH beads at predicted anticancer cytotoxic concentrations for 2 to 5 cm. CONCLUSIONS AND CLINICAL RELEVANCE Results provided information regarding the spatial distribution of platinum expected to occur in vivo. Agarose may be used as a diffusion model, mimicking the characteristics of subcutaneous tissues. Measured platinum concentrations might be used to guide patterns for implantation of CI-CSH beads in animals with susceptible neoplasms.

In vitro chemosensitivity of feline injection site-associated sarcoma cell lines to carboplatin.

OBJECTIVE: To determine the in vitro chemosensitivity of feline injection site-associated sarcoma (FISAS) cells to carboplatin concentrations generated by elution of carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads. STUDY DESIGN: In vitro study. SAMPLE: Five immortalized cell lines from histologically confirmed, primary FISASs. METHODS: For each cell line, one 96-well microplate was used for each time point (24, 48, 72 hours). In each microplate, 3 wells were seeded with ∼7.5 × 103 cells per well for every carboplatin treatment added, ranging from 5 to 450 µM. Microculture plates were incubated for 24, 48, or 72 hours. Drug efficacy was assessed via a bioreductive fluorometric assay. For apoptosis analysis, 3 wells were seeded with ∼5 × 104 cells per well for every carboplatin treatment added, ranging from 5 to 450 µM. Flow cytometry was performed and the relative percentages of viable, apoptotic, and late apoptotic/necrotic cells were reported. All experiments were run in triplicates. RESULTS: Carboplatin exerted dose-dependent and time-dependent effects on FISAS cell viability. The IC50 values were within the range of carboplatin concentrations eluted from CI-CSH beads. CONCLUSION: Elution of carboplatin from CI-CSH beads generate concentrations sufficient to result in 50% growth inhibition of FISAS cells in vitro. Local tumor control might be achieved by implantation of CI-CSH beads immediately following radical or marginal excision of the primary tumor or by implantation without tumor resection.