Management of proximal metaphyseal curvilinear tibial fractures in 25 skeletally immature dogs (2009 to 2020).

OBJECTIVES: To describe the occurrence, management and outcome of proximal metaphyseal curvilinear tibial fractures in skeletally immature dogs. MATERIALS AND METHODS: A multi-centre retrospective review was conducted, searching for skeletally immature dogs presenting with proximal metaphyseal curvilinear tibial fractures between January 2009 and September 2020. Signalment, fracture description and case management data were retrieved. Outcome was assessed by retrospectively evaluating follow-up radiographs, hospital records and an owner questionnaire. RESULTS: Twenty-five dogs met the inclusion criteria. All but one fracture was a result of minimal trauma. Twenty fractures were managed with internal fixation, two with external fixation and three conservatively. All 25 fractures healed. Eight major complications occurred in seven of 25 (28%) dogs. Twelve minor complications occurred in 10 of 25 (40%) dogs. Owner questionnaire data were available for 12 of 25 dogs; 11 of 12 were reported as having full function and one of 12 as having acceptable function at the time of questioning (median 34.5 months following presentation). At final follow-up, either by clinical examination or owner questionnaire, full function was achieved in 22 of 25 patients and acceptable function in three of 25. CLINICAL SIGNIFICANCE: This study reported a series of proximal metaphyseal tibial fractures in skeletally immature dogs. The most common fixation method was internal fixation, which frequently resulted in full limb function at final follow-up. Owners reported outcome as fully functional in all dogs that underwent surgery at first presentation and had owner follow-up available, though positive outcomes may have been affected by participation bias.

Retrospective study of complications associated with surgically-placed gastrostomy tubes in 43 dogs with septic peritonitis.

OBJECTIVES: To determine the safety of surgically-placed gastrostomy feeding tubes in dogs with septic peritonitis. MATERIALS AND METHODS: Retrospective analysis of 43 dogs with septic peritonitis that had undergone surgical exploration and gastrostomy tube (de Pezzer or Foley) placement as part of the surgical procedure. Postoperative recovery times, hospitalisation times, complication rates and overall survival times were documented. RESULTS: The most common cause of septic peritonitis was dehiscence of an enterotomy or enterectomy site. Fifteen dogs had a Foley gastrostomy tube placed and 28 had a de Pezzer gastrostomy tube placed. The median time from surgery to the start of enteral nutrition was 16 hours (range 3 to 28 hours). There were no major complications relating to the gastrostomy tube; minor complications occurred in 11 (26%) patients. The overall median time spent in hospital was 5 days (range 3 to 29 days) for patients surviving to discharge and 22 (51%) dogs survived overall. CLINICAL SIGNIFICANCE: Gastrostomy feeding tubes provide a safe way to provide enteral nutrition to dogs with septic peritonitis; they are associated with a low complication rate in these patients.

Origin of leukemic relapse after bone marrow transplantation detected by restriction fragment length polymorphism.

Bone marrow transplantation has become an accepted modality in the treatment of acute leukemia. With this therapy, it is possible to obtain long-term disease-free survival. However, leukemia recurs occasionally. In most cases, leukemic relapse is of recipient origin. There have been several reports, though, of leukemia developing in donor cells. These cases have been limited to instances in which there is an easily identifiable chromosome difference or abnormality, usually a sex chromosome. In this paper we describe the use of restriction fragment-length polymorphism analysis to determine the origin of recurrent leukemia cells in which no identifying chromosome was present. We found that the leukemia had recurred in recipient cells. We also were able to demonstrate the presence of normal hemopoietic cells of donor origin.

Severe deficiency of B lymphocytes in peripheral blood from multiple myeloma patients.

A major problem in the assessment of circulating B lymphocytes in multiple myeloma is the extent to which cells with passively absorbed Ig contribute to the assay. We have analyzed peripheral blood B cell numbers in 51 patients in various treatment categories by using an assay that is not subject to artifacts involving cytophilic Ig. We have defined a B lymphocyte by three different criteria (a) expression of a high surface density of Ig (b) expression of a high density of HLA.DR and (c) expression of a marker exclusive to surface Ig+ B cells. By these criteria, normal individuals have an average of 6% B cells. In multiple myeloma patients, B cell levels in purified mononuclear cell preparations are severely reduced. Untreated patients and the majority of patients on intermittent chemotherapy have 20-600-fold fewer B cells than do normal donors (average = 0.3%). This decrease was even greater in whole blood of patients as compared with normal donors (100-1,000-fold fewer B cells). The number of B cells did not correlate with disease status or paraprotein concentration. We found no evidence to support the idea that B lymphocytes in patients include a substantial monoclonal subset.

International uniform response criteria for multiple myeloma.

New uniform response criteria are required to adequately assess clinical outcomes in myeloma. The European Group for Blood and Bone Marrow Transplant/International Bone Marrow Transplant Registry criteria have been expanded, clarified and updated to provide a new comprehensive evaluation system. Categories for stringent complete response and very good partial response are added. The serum free light-chain assay is included to allow evaluation of patients with oligo-secretory disease. Inconsistencies in prior criteria are clarified making confirmation of response and disease progression easier to perform. Emphasis is placed upon time to event and duration of response as critical end points. The requirements necessary to use overall survival duration as the ultimate end point are discussed. It is anticipated that the International Response Criteria for multiple myeloma will be widely used in future clinical trials of myeloma.

Detection of genes with moderate effects on disease resistance using ovine mhc and resistance to nematodes as an example.

Detecting some of the genes that influence disease resistance would improve our understanding of the processes that cause disease and also simplify disease control. Genes within the major histocompatibility complex (mhc) are strong candidates for disease resistance and they have been intensely studied for the last 30 years. Recently, several groups working independently have reported the existence of alleles within the mhc that are associated with enhanced resistance to nematode infection. This article uses hindsight to describe some of the potential pitfalls that hinder the search for valid disease resistance genes. The search requires a good understanding of disease biology, molecular genetics, statistical genetics and especially, the design and analysis of experiments. The power to detect mhc effects is quite low and is quite sensitive to the frequency of the putative resistance alleles.

Modified tube gastropexy using a mushroom-tipped silicone catheter for management of gastric dilatation-volvulus in dogs.

OBJECTIVES: To report the short- and long-term complications and clinical outcomes of a cohort of dogs managed for gastric dilatation-volvulus using a modified right-sided tube gastropexy technique. MATERIALS AND METHODS: Retrospective case series. RESULTS: Of 31 dogs treated, 29 (93·5%) had an excellent short-term outcome, and gastric dilatation-volvulus did not recur in any dog. Twenty-six dogs (84%) were initially fed via the gastrostomy tube postoperatively; three (9·7%) suffered a major complication including septic peritonitis (n=1), and premature tube removal (n=2). Fourteen dogs (45·1%) had minor complications including mild, self-limiting discharge from the stoma site in 13. CLINICAL SIGNIFICANCE: Modified tube gastropexy using a mushroom-tipped silicone catheter is an effective and safe surgical method for the management of gastric dilatation-volvulus. The gastrostomy tube allowed early enteral feeding and easy administration of medications, including gastroprotectants.

Comparison of the use of LigaSure versus a standard technique for tonsillectomy in dogs.

The principal aim of this study was to document the effectiveness of tonsillectomy in dogs using a vessel-sealing device compared with a standard technique with tonsillectomy forceps. A secondary aim of the study was to document histopathological changes of the excised tonsillar tissue in dogs with brachycephalic obstructive airway syndrome. 20 dogs were studied. The time taken to remove a tonsil using LigaSure was a mean of 44.8 seconds (sd 15 seconds, 95 per cent CI 40  to 57 seconds) and with the standard technique a mean of 305.9 seconds (sd 67 seconds, 95 per cent CI 272  to 349 seconds). Significantly less haemorrhage occurred using LigaSure compared with the standard technique. Histopathology of the tonsils was characterised by multifocal neutrophilic and lymphocytic inflammation, and 1-2 mm of heat-induced coagulation necrosis at the cut edge of LigaSure tonsils. This study shows that LigaSure is significantly faster and resulted in less bleeding than the standard technique.

Liposomal encapsulated doxorubicin (Caelyx) in the treatment of relapsed aggressive non-Hodgkin's lymphoma: a phase II study.

Aggressive non-Hodgkin's lymphoma (NHL), such as diffuse large B-cell lymphoma, can be cured in approximately 50% of cases, but those cases that recur and are not amenable to high-dose chemotherapy rely on palliative chemotherapy to improve symptoms and prolong life. Anthracyclines are associated with a high response rate in aggressive NHL but extended treatment results in cardiotoxicity. Liposomal encapsulated doxorubicin has been shown in other tumor types to allow for extended treatment with doxorubicin, but is associated with a low cardiac risk. The present study aimed to assess the response rate, survival and cardiac risk of patients with relapsed aggressive NHL treated with liposomal encapsulated doxorubicin. Eighteen patients with relapsed aggressive NHL were treated with liposomal encapsulated doxorubicin (40 - 50 mg/m2) for a planned six cycles. Some 83% of patients had diffuse large B-cell or mantle cell NHL. Four patients had a partial response (23%), whereas five patients had stable disease. None had a complete response. Eight patients progressed when receiving the liposomal encapsulated doxorubicin therapy. The median survival time was 34 weeks, and the median progression-free survival was 15.7 weeks. Overall survival was 50% at 6 months and 39% at 12 months. Progression-free survival was 33% at 6 months and was 28% at 12 months. The mean ejection fraction pre- and post-liposomal encapsulated doxorubicin treatment remained the same. Only one patient had a drop in ejection fraction to <50%. Liposomal encapsulated doxorubicin offers another choice to patients seeking palliation from their lymphoma recurrence with a response rate of 23% that was well tolerated and had a minimal cardiotoxic risk.

Dose intensity analysis of melphalan and prednisone in multiple myeloma.

The average relative dose intensity (DI) of conventional oral melphalan and prednisone therapy received by 93 newly diagnosed multiple myeloma patients was correlated with survival and with percent reduction in M-protein. A survival advantage was shown with increasing average relative DI of melphalan and prednisone. Multivariate analysis showed survival to correlate with increasing DI of prednisone (P = .05) but not with the DI of melphalan (P = .93) nor with the percent decrement in M-protein (P = .10). These results suggest that the initial management of myeloma should be reassessed, with particular emphasis on more intensive therapy employing high-dose steroids.

L-phenylalanine mustard (melphalan) uptake and cross-linking in the RPMI 6410 human lymphoblastoid cell line.

L-Phenylalanine mustard (melphalan) induced a time- and concentration-dependent arrest of cycling RPMI 6410 cells in the G2 phase of the cell cycle as evidenced by flow cytofluorometry. A melphalan exposure of 1 microgram/ml for 1 hr caused a temporary G2 blockage which was overcome by 48 hr. Higher concentrations or longer exposures lead to irreversible blockages. Melphalan caused DNA cross-linking which was monitored by the alkaline elution method. The cross-linking was shown to be between DNA and protein. The degree of DNA cross-linking increased for approximately 4 hr after a 1-hr drug exposure of 1 microgram/ml. At 36 to 48 hr after the drug exposure, the cells overcame the G2 block and were dividing. The DNA cross-links have apparently been repaired as they are no longer detected by alkaline elution. The extent of melphalan cross-linking was dependent on both drug dosage and exposure time. Using a culture medium lacking amino acids, it was shown that melphalan uptake into RPMI 6410 cells was inhibited by leucine, isoleucine, or glutamine. The increased uptake of melphalan and the increased cross-linking in amino acid-deficient media were reduced by readdition of the aforementioned amino acids.

Formation of 1-beta-D-arabinofuranosylcytosine diphosphate choline in neoplastic and normal cells.

1-beta-D-Arabinofuranosylcytosine diphosphate choline was formed from 1-beta-D-arabinofuranosylcytosine (ara-C) during incubation in vitro of peripheral myeloblasts from patients with acute myelogenous leukemia and cultured cells (nonleukemic human lymphocytes, mouse lymphoma L5178Y, and HeLa); as well, 1-beta-D-arabinofuranosylcytosine diphosphate choline was formed in vivo in mouse leukemia L1210 cells and mouse liver. 3-Deazauridine enhanced the anabolism of ara-C in nonleukemic lymphocytes in vitro and leukemia L1210 cells in vivo but did not influence ara-C anabolism in the other cell types. In acute myelogenous leukemia myeloblasts incubated in vitro with ara-C, concentrations of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate were maximal after 8 hr of incubation and formation of the latter preceded that of 1-beta-D-arabinofuranosylcytosine diphosphate choline.

DNA strand breaks induced in human T-lymphocytes by the combination of deoxyadenosine and deoxycoformycin.

There is a progressive loss of human T-lymphocyte viability upon incubation with deoxycoformycin, an adenosine deaminase inhibitor, and low concentrations of deoxyadenosine (drug concentration that reduced cell count at 48 hr after initiation to 50% of value for untreated control culture, less than 1 microM). The loss of viability was evidenced by vital staining with fluorescein diacetate and by changes in forward single light scatter measured by flow cytometry. This loss of lymphocyte viability is detectable 18 to 20 hr after the addition of deoxyadenosine and is earlier than has been reported by other investigators using trypan blue as the vital stain. Alkaline elution studies show that the incubation of T-lymphocytes with the combinations of deoxycoformycin and deoxyadenosine gives rise to DNA single-strand breaks. These DNA strand breaks are dose and time dependent and are readily detected 4 hr after the addition of deoxyadenosine. These DNA lesions are not observed with deoxycoformycin or deoxyadenosine alone. Incubations of T-lymphocytes with deoxycoformycin and deoxyadenosine (1 and 5 microM) for 7 hr result in DNA strand breaks with a frequency of 145 and 280 rad equivalents, respectively. Preliminary studies indicate that the ability of lymphocytes to repair this damage is dependent upon deoxyadenosine concentration and exposure time. The relationship of these DNA lesions to loss of lymphocyte viability in the presence of deoxycoformycin and deoxyadenosine remains to be established.

Adhesion of multiple myeloma peripheral blood B cells to bone marrow fibroblasts: a requirement for CD44 and alpha4beta7.

We have earlier described the presence of phenotypically unusual monoclonal B cells within the peripheral blood of multiple myeloma (MM) patients. To determine the biological properties of these B cells as compared to B cells from normal donors, we investigated the potential of CD19+ MM blood B cells to adhere to endothelial cell and bone marrow (BM)-fibroblast monolayers. We find that 30-60% of freshly isolated CD19+ MM blood B cells adhere to endothelial cell monolayers, and 50-80% adhere to BM fibroblast monolayers. The adhesion of MM blood B cells to either monolayer was not increased by in vitro activation, suggesting that these cells were activated in vivo. In contrast, fewer than 10% of CD19+ B cells from peripheral blood of normal donors adhered. Function-blocking monoclonal antibodies (mAbs) were used to determine which adhesion receptors were involved in CD19+ MM blood B cell interaction with BM fibroblasts. mAbs against very late antigen 4, the beta7-integrin subunit, and CD44, but not mAbs against very late antigen 5 and beta1, inhibited adhesion 61, 50, and 30%, respectively. The lack of inhibition with mAbs against beta1 implicates alpha4beta7 but not alpha4beta1 in adhesion of CD19+ MM blood B cells. To determine the alpha4beta7 ligand that mediated MM blood B cell adhesion, mAbs against vascular cellular adhesion molecule 1 and fibronectin, as well as CS1 and RGD peptides, were used as inhibitors. These were unable to reduce the adhesion of CD19+ MM blood B cells to BM fibroblasts, suggesting that fibronectin and vascular cellular adhesion molecule 1 are not involved in adhesion. Also, adhesion of MM blood B cells to mucosal addressin cell adhesion molecule 1-transfected Chinese hamster ovary cells was not enhanced compared to control-transfected Chinese hamster ovary cells, suggesting that mucosal addressin cell adhesion molecule 1 was not promoting adhesion of these cells. These data implicate CD44:HA interactions, as well as alpha4beta7 and an as yet unidentified ligand in the adhesion of in vivo activated MM blood B cell adhesion to BM fibroblasts. The adhesion properties of MM CD19+ B cells distinguishes them from normal B cells. Although the malignant status of these cells is as yet undefined, their adhesion properties implicate MM blood B cells in migratory spread of the disease.

Cost-effectiveness of lenalidomide plus dexamethasone vs. bortezomib plus melphalan and prednisone in transplant-ineligible U.S. patients with newly-diagnosed multiple myeloma.

OBJECTIVE: To conduct a cost-effectiveness assessment of lenalidomide plus dexamethasone (Rd) vs bortezomib plus melphalan and prednisone (VMP) as initial treatment for transplant-ineligible patients with newly-diagnosed multiple myeloma (MM), from a U.S. payer perspective. METHODS: A partitioned survival model was developed to estimate expected life-years (LYs), quality-adjusted LYs (QALYs), direct costs and incremental costs per QALY and LY gained associated with use of Rd vs VMP over a patient's lifetime. Information on the efficacy and safety of Rd and VMP was based on data from multinational phase III clinical trials and a network meta-analysis. Pre-progression direct costs included the costs of Rd and VMP, treatment of adverse events (including prophylaxis) and routine care and monitoring associated with MM. Post-progression direct costs included costs of subsequent treatment(s) and routine care and monitoring for progressive disease, all obtained from published literature and estimated from a U.S. payer perspective. Utilities were obtained from the aforementioned trials. Costs and outcomes were discounted at 3% annually. RESULTS: Relative to VMP, use of Rd was expected to result in an additional 2.22 LYs and 1.47 QALYs (discounted). Patients initiated with Rd were expected to incur an additional $78,977 in mean lifetime direct costs (discounted) vs those initiated with VMP. The incremental costs per QALY and per LY gained with Rd vs VMP were $53,826 and $35,552, respectively. In sensitivity analyses, results were found to be most sensitive to differences in survival associated with Rd vs VMP, the cost of lenalidomide and the discount rate applied to effectiveness outcomes. CONCLUSIONS: Rd was expected to result in greater LYs and QALYs compared with VMP, with similar overall costs per LY for each regimen. Results of this analysis indicated that Rd may be a cost-effective alternative to VMP as initial treatment for transplant-ineligible patients with MM, with an incremental cost-effectiveness ratio well within the levels for recent advancements in oncology.

Selective targeting of immunoliposomal doxorubicin against human multiple myeloma in vitro and ex vivo.

Circulating malignant CD19(+) B cells have been implicated in the pathogenesis and relapse of multiple myeloma (MM). This study investigated the therapeutic applicability of using long-circulating liposome-encapsulated doxorubicin (DXR) targeted against the internalizing CD19 antigens present on human MM cells. In vitro binding studies using the CD19(+) MM cell line ARH77 demonstrated that CD19-directed immunoliposomes (SIL[anti-CD19]) specifically attached to these cells. Formulations of immunoliposomal doxorubicin (DXR-SIL[anti-CD19]) showed a higher association with, and higher cytotoxicity against, ARH77 cells than did non-targeted liposomal doxorubicin (DXR-SL) or isotype-matched controls (DXR-NSIL[IgG2a]). By using the pH-sensitive fluorophore, 1-hydroxypyrene-3,6, 8-trisulfonic acid, binding of SIL[anti-CD19] to CD19 antigens was shown to trigger receptor-mediated internalization of the antibody-antigen complexes into endosomes. Targeting of SIL[anti-CD19] to CD19(+) B cells was also demonstrated in a heterogeneous mixture of peripheral blood mononuclear cells (PBMC) from MM patients. A decrease in cellular DNA (which is an indicator of apoptosis) caused by the cytotoxicity of DXR-SIL[anti-CD19] to myeloma PBMC was determined by using flow cytometry. While PBMC treatment with free DXR resulted in non-specific cytotoxicity to both B and T cells, DXR-SL were only minimally cytotoxic to either. In contrast, DXR-SIL[anti-CD19] were selectively cytotoxic for B cells in PBMC, indicating that this treatment may be effective in eliminating circulating malignant B cells in MM patients.

Are the current criteria for response useful in the management of multiple myeloma?

One hundred seventy-three patients with multiple myeloma were treated from the time of diagnosis with standard oral melphalan and prednisone at 28-day intervals until they became refractory to treatment. Response to treatment was determined according to the Chronic Leukemia-Myeloma Task Force (TF) criteria, and independently according to the Southwest Oncology Group (SWOG) criteria. Survival by disease stage and response according to the two sets of criteria were analyzed for patients living longer than 3 months. The median survival of responding and nonresponding (TF criteria) stage II patients was 43.8 and 40.3 months, respectively (P = .29). By SWOG criteria, median survival for responding and nonresponding stage II patients was 48.3 and 39.0 months, respectively (P = .12). In stage III patients, median survival for responders and nonresponders (TF criteria) was 34.0 and 21.7 months, respectively (P = .01), compared with 35.5 and 24.4 months (P = .04) by SWOG criteria. These data would suggest that the TF criteria predicts a survival disadvantage only in very advanced myeloma and that applying the stricter limits for the definition of response of the SWOG does not further aid in selecting a subgroup of myeloma patients with poorer survival.

Effect of daily etidronate on the osteolysis of multiple myeloma.

Progressive bone disease in multiple myeloma frequently leads to osteolysis, bone resorption, pathologic fractures, vertebral compression, and hypercalcemia. We conducted a double-blind study in 173 newly diagnosed multiple myeloma patients of etidronate disodium (EHDP), a diphosphonate compound that reduces bone resorption by inhibiting osteoclastic activity. The patients were randomly assigned to receive oral EHDP 5 mg/kg/d or placebo until death or discontinuation due to intolerance or refusal. The extent of vertebral deformity was measured by a vertebral index as well as height. The frequency of pathologic fractures, hypercalcemia, and bone pain was regularly assessed, as well as size and number of osteolytic lesions. All patients received melphalan and prednisone daily for 4 days every 4 weeks as the primary chemotherapy for their disease. Although the repeated measures analysis showed a significant height loss, there was no difference between treatment arms (P = .98). There was no significant difference in bone pain, episodes of hypercalcemia, or development of pathologic fractures. Patients on EHDP showed less deterioration in their vertebral index, but this difference only approached statistical significance (P = .07). We conclude that EHDP therapy used in this dosage schedule does not have a clinically significant impact in multiple myeloma.

Randomized trial of interferon maintenance in multiple myeloma: a study of the National Cancer Institute of Canada Clinical Trials Group.

PURPOSE: To determine whether interferon maintenance therapy improves overall survival and response duration in patients with multiple myeloma who have responded to induction therapy with melphalan and prednisone. PATIENTS AND METHODS: In a multicenter trial, patients with symptomatic clinical stage I and stage II and III multiple myeloma were registered at diagnosis and those who responded to melphalan-prednisone (MP) were randomized either to receive interferon (2 mU/m2) subcutaneously three times per week or no maintenance. MP was discontinued in both groups once a stable response plateau of the monoclonal protein was reached. Interferon was continued until relapse, and then was restarted on subsequent response to MP. Interferon toxicity was recorded using a self-report diary. Survival and response duration were calculated using life-table methods, and were adjusted in the analysis for imbalances in baseline prognostic factors. RESULTS: Four hundred two patients were registered and 176 responders were randomized (85 to interferon and 91 to control). At a median follow-up time of 43 months, the median survival duration was 43 months for interferon and 35 months for control (P = .16), but when adjusted for chance imbalances in baseline prognostic factors (mainly performance status), the median survival duration was 44 months and 33 months for interferon and control, respectively (P = .049). Progression-free survival from randomization to first relapse also favored interferon (unadjusted P < .002; adjusted P < .003). Interferon toxicity caused 58% of patients to reduce their dose, of which 84% were able to return to the initial dose; 14% had to discontinue interferon treatment. CONCLUSION: Interferon maintenance therapy improves progression-free and overall survival of patients with multiple myeloma who respond to melphalan and prednisone. Toxicity is substantial and must be weighed by patients against the potential benefits in response duration and survival.

The blood B-cells and bone marrow plasma cells in patients with multiple myeloma share identical IgH rearrangements.

Previous reports have described the phenotypic and functional properties of monotypic late stage B cells in the blood of patients with multiple myeloma and have speculated that these B cells represent a malignant circulating component of myeloma. Here we show that blood B cells have IgH rearrangements identical to those expressed by the bone marrow plasma cells by using Ig Fingerprint and Allele-Specific Oligomer (ASO) polymerase chain reaction (PCR) methods. DNA from purified blood B cells and bone marrow plasma cells taken at the same time, and blood B cells taken at subsequent patient visits was amplified using consensus IgH primers, or ASO primers. In 10/16 patients, a single IgH rearrangement was amplified from the bone marrow plasma cells. In all 10 of those patients the same clonotypic rearrangement was amplified from the purified blood B cells. The relationship of these clonal blood B cells to the malignant bone marrow plasma cells remains undetermined.