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Biomedical subjects

D M Vail

Publications and source records attributed to D M Vail.

At least 19 recordsLinked to original sources

Outcome and prognostic factors following adjuvant prednisone/vinblastine chemotherapy for high-risk canine mast cell tumour: 61 cases.

The medical records of 61 dogs with MCT at high risk for metastasis that were treated with prednisone and VBL following excision+/-radiation therapy were reviewed, and median disease-free interval (DFI), median overall survival time (OS) and prognostic factors assessed. Adverse effects, mostly mild, were noted in 26% of patients, usually after the first VBL dose. 6.5% experienced severe neutropenia. The DFI was 1305 days, and the OS was not reached, with 65% alive at 3 years. 100% of dogs with "high-risk" grade II MCT were alive at 3 years. The OS for dogs with grade III MCT was 1374 days. Histologic grade, location (mucous membrane vs. skin) and use of prophylactic nodal irradiation predicted outcome. Prednisone and VBL chemotherapy is well tolerated, and results in good outcomes following surgery in dogs with MCT at high risk for metastasis. High-grade and mucocutaneous tumors had a worse outcome, and the use of prophylactic nodal irradiation appeared to improve outcome in this group of dogs.

Animals↗

Development of an allogeneic whole-cell tumor vaccine expressing xenogeneic gp100 and its implementation in a phase II clinical trial in canine patients with malignant melanoma.

A xenogeneic melanoma-antigen-enhanced allogeneic tumor cell vaccine (ATCV) is an appealing strategy for anti-cancer immunotherapy due to its relative ease of production, and the theoretical possibility that presentation of a multiplex of antigens along with a xenogeneic antigen would result in cross-reaction between the xenogeneic homologs and self-molecules, breaking tolerance and ultimately resulting in a clinically relevant immune response. In this study, we evaluated the efficacy of such a strategy using a xenogeneic melanoma differentiation antigen, human glycoprotein 100 (hgp100) in the context of a phase II clinical trial utilizing spontaneously arising melanoma in pet dogs. Our results demonstrate that the approach was well tolerated and resulted in an overall response rate (complete and partial response) of 17% and a tumor control rate (complete and partial response and stable disease of >6 weeks duration) of 35%. Dogs that had evidence of tumor control had significantly longer survival times than dogs that did not experience control. Delayed type hypersensitivity (DTH) to 17CM98 canine melanoma cells used in the whole cell vaccine was enhanced by ATCV and correlated with clinical response. In vitro cytotoxicity was enhanced by ATCV, but did not correlate with clinical response. Additionally, anti-hgp100 antibodies were elicited in response to ATCV in the majority of patients tested; however, this also did not correlate with clinical response. This approach, along with further elucidation of the mechanisms of tumor protection after xenogeneic immunization, may allow the development of more rational vaccines. This trial also further demonstrates the utility of spontaneous tumors in companion animals as a valid translational model for the evaluation of novel vaccine therapies.

Animals↗

Development of inhalational agents for oncologic use.

Because regional chemotherapy has been useful in treatment and palliation of many cancer types, the concept of delivering drugs by inhalation for the treatment of cancers in the lung is attractive. Much higher local drug exposure can be achieved with total doses considerably lower than those required for systemic administration, resulting in lower exposure of nonrespiratory tract tissues to potentially toxic drugs. Regional delivery of chemotherapy to the respiratory tract has been shown to have activity in preclinical and clinical studies. Technical improvements in delivery methods have now made it possible to conduct trials of inhalational agents, both to treat cancers affecting the respiratory tract and to deliver other drugs used in cancer patients. This review discusses the rationale of drug delivery by the inhalational route, its technical challenges, preclinical and clinical experiences, limitations, and promise.

Administration, Inhalation↗

Prognosis for presumed feline vaccine-associated sarcoma after excision: 61 cases (1986-1996).

OBJECTIVE: To evaluate time to first recurrence (TFR) and overall survival in cats with presumed vaccine-associated sarcomas (VAS) treated with excision. DESIGN: Retrospective study. ANIMALS: 61 cats with presumed VAS. PROCEDURE: Medical records of cats that received excision as the only initial treatment for presumed VAS were reviewed to evaluate prognosis. Overall survival curves and TFR were determined. RESULTS: Median TFR was 94 days. Median TFR for tumors treated with excision performed at a referral institution (274 days) was significantly longer than that for tumors excised by a referring veterinarian (66 days). Radical first excision yielded significantly longer median TFR (325 days) than did marginal first excision (79 days). Cats with tumors located on the limbs had longer median TFR (325 days) than cats with tumors located in other sites (66 days). Median overall survival time was 576 days. Significant differences in survival times between groups were not detected. Few cats (13.8%) receiving only surgical treatment had long-term (> 2 years) survival. CONCLUSIONS AND CLINICAL RELEVANCE: Radical first excision of presumed VAS is essential for extended TFR. Current recommendations for vaccination of the distal portions of the extremities are appropriate, because this practice permits radical excision of tumors (amputation) that develop at vaccination sites; however, surgery alone is seldom curative.

Animals↗

Use of cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum (II), a liposomal cisplatin analogue, in cats with oral squamous cell carcinoma.

OBJECTIVE: To determine clinical response and toxic effects of cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum (II) (L-NDDP) administered i.v. at escalating doses to cats with oral squamous cell carcinoma (SCC). ANIMALS: 18 cats with oral SCC. PROCEDURE: Cats that failed to respond to conventional treatment or had nonresectable tumors were included. Data included a CBC, serum biochemical analyses, urinalysis, cytologic examination of a fine-needle aspirate of enlarged lymph nodes, and thoracic and oral radiographs for clinical staging. A starting dose (75 to 100 mg/m2 of L-NDDP) was administered i.v.. At 21-day intervals, subsequent doses increased by the rate of 5 or 10 mg/m2. Response was evaluated every 21 days by tumor measurement and thoracic radiography. Quality of life was assessed by owners, using a performance status questionnaire. RESULTS: On average, cats received 2 treatments. Toxicoses included an intermittent, acute anaphylactoid-parasympathomimetic reaction, lethargy or sedation (< or = 24 hours), inappetence or signs of depression (< or = 72 hours), mild to moderate increase in hepatic enzyme activity, and melena. Pulmonary, renal, or hematopoietic abnormalities were not evident. Performance status surveys indicated normal behavior and grooming or decreased activity and self-care (19/20 assessments), ate well with or without assistance (15/20), and did not lose weight (15/20). Median survival time was 59.8 days (mean, 54.1 days). CONCLUSIONS AND CLINICAL RELEVANCE: L-NDDP was ineffective for treatment of cats with oral SCC. None of the cats had a complete or partial remission. Acute toxicoses and poor therapeutic response limit therapeutic usefulness of L-NDDP in cats, unless dosage, frequency, and administration procedures can be improved.

Animals↗

Spontaneously occurring tumors of companion animals as models for human cancer.

Spontaneous tumors in companion animals (dog and cat) offer a unique opportunity as models for human cancer biology and translational cancer therapeutics. The relatively high incidence of some cancers, similar biologic behavior, large body size, comparable responses to cytotoxic agents, and shorter overall lifespan are the factors that contribute to the advantages of the companion animal model. The tumor types that offer the best comparative interest include lymphoma/leukemia, osteosarcoma, STS, melanoma, and mammary tumors. With the increase in new therapeutic agents (traditional chemotherapy, gene therapy, biologic agents, etc.), the companion animal model can provide useful populations to test new agents where efficacy and toxicity can be examined.

Animal Diseases↗

In vitro and in vivo enhancement of canine pulmonary alveolar macrophage cytotoxic activity against canine osteosarcoma cells.

The combination of chemotherapy with immunotherapy may offer an advantage over either therapy alone and provide a greater potential for total tumor eradication. Monocyte/macrophage-mediated tumor cell killing is a major mechanism of the host's defense against primary and/or metastatic neoplasia. We evaluated the tumoricidal activity against canine osteosarcoma cells of canine pulmonary alveolar macrophages (PAM) exposed in vitro to two recombinant canine (rc) cytokines (rcTNF alpha and rcIFN gamma). We also evaluated the in vivo tumoricidal activity of PAM from dogs treated with the macrophage activator, liposome-encapsulated muramyl tripeptide-phosphatidyl-ethanolamine (L-MTP-PE) alone or in combination with doxorubicin (DOX). This study demonstrated that rcTNF alpha and rcIFN gamma significantly enhance in vitro canine PAM cytotoxicity against canine osteosarcoma cells, and that PAM from dogs treated with DOX + L-MTP-PE have enhanced cytotoxic activity against osteosarcoma cells when compared to dogs treated with DOX or L-MTP-PE alone. These findings support the rationale for combining a chemotherapy agent with an immunotherapy agent for the treatment of metastatic disease, and suggest a role for TNF alpha and IFN gamma as agents for stimulating the antitumor activity of macrophages.

Acetylmuramyl-Alanyl-Isoglutamine↗

The immunotherapeutic potential of activated canine alveolar macrophages and antitumor monoclonal antibodies in metastatic canine melanoma.

A variety of immune cell activators can enhance the cytotoxic effects of monocytes/macrophages including interferon-gamma (IFN-gamma) and muramyl peptides, which are under investigation for cancer therapy in humans and dogs. Pulmonary alveolar macrophages (PAMs) in particular, are strategically located within the lung and provide a potential defense against cancer cells metastatic to the lung. For this reason, we examined the in vitro cytotoxic potential of fresh and IFN-gamma-activated PAMs from normal dogs targeted to canine malignant melanoma cells with antiganglioside monoclonal antibodies (mAbs). Antiganglioside mAbs 14.G2a (anti-GD2) and R24 (anti-GD3), both in clinical trials for human neuroectodermal tumors including melanoma, significantly enhanced the cytotoxicity of canine melanoma mediated by canine PAMs. Further, the cytotoxicity mediated by recombinant canine IFN-gamma-activated canine PAMs, in combination with anti-GD2 ganglioside mAb 14.G2a, enhanced melanoma cytotoxicity above that seen with mAb 14.G2a alone. This documentation of antibody-dependent cellular cytotoxicity mediated by activated PAMs suggests that activation and targeting of resident pulmonary immune cells be pursued as a means to control pulmonary metastases.

Adjuvants, Immunologic↗

Inhalation chemotherapy for macroscopic primary or metastatic lung tumors: proof of principle using dogs with spontaneously occurring tumors as a model.

This study represents part of an effort to determine the safety and efficacy of inhaled antineoplastic drugs, using pet dogs with spontaneously arising primary and metastatic lung cancers (including sarcoma, carcinoma, and malignant melanoma) as a model. Dogs received new formulations of either paclitaxel (PTX) or doxorubicin (DOX) by the inhalation route every 2 weeks using a specially designed aerosol device. Response was assessed radiographically using the indices of tumor nodule number and volume measurement of discrete pulmonary nodules. Dogs experiencing progressive disease after two consecutive treatments were crossed over to receive the alternate compound. In 24 dogs, 6 (25%) responses were noted including 5 partial responses (PR) and 1 complete response. These include 4 (22.2%) of 18 responses to DOX and 2 (13.3%) of 15 responses to PTX. Responses were noted with osteosarcoma (including three dogs with metastatic osteosarcoma that had failed prior systemic chemotherapy), liposarcoma, hemangiosarcoma, and undifferentiated sarcoma. One dog with mammary carcinoma experienced a 47% reduction in volume after PTX inhalation, just shy of PR criteria. One dog with liposarcoma is experiencing a long-term (>12 months) stabilization of disease on PTX. To date, no systemic toxicities have been observed with either PTX or DOX inhalations. Local (pulmonary) toxicity was not observed with PTX; however, changes consistent with pneumonitis/fibrosis were observed in some dogs receiving DOX. Only one of these dogs showed clinical signs, which were responsive to steroid and antitussive therapy. These data represent "proof of principle" for the avoidance of systemic toxicity while delivering efficacious local drug levels by the inhalation route.

Administration, Inhalation↗

Adjuvant therapy for melanoma in dogs: results of randomized clinical trials using surgery, liposome-encapsulated muramyl tripeptide, and granulocyte macrophage colony-stimulating factor.

Spontaneous canine oral melanoma (COM) is a highly metastatic cancer, resistant to chemotherapy, and can serve as a model for cancer immunotherapy. Liposome-encapsulated muramyl tripeptide-phosphatidylethanolamine (L-MTP-PE) can activate the tumoricidal activity of the monocyte-macrophage system following i.v. injection. The objective of these studies was to evaluate the therapeutic effectiveness of L-MTP-PE administered alone and combined with recombinant canine granulocyte macrophage colony-stimulating factor (rcGM-CSF) in dogs undergoing surgery for oral melanoma. Ninety-eight dogs with histologically confirmed, clinically staged, oral melanoma were entered into two randomized, double-blind, surgical adjuvant trials. In trial 1, 50 dogs were stratified based on clinical stage and randomized to once a week L-MTP-PE or lipid equivalent (control). When all of the clinical stages were combined, no difference in disease-free survival or in survival time (ST) were detected. However, within stage I, dogs receiving L-MTP-PE had a significant increase in ST compared with control, with 80% of the dogs treated with L-MTP-PE still alive at >2 years. Within each stage II and stage III, there was no difference detected between the treatment groups. In trial 2, 48 dogs were stratified on the basis of clinical stage and extent of surgery (simple resection or radical excision), treated with L-MTP-PE two times a week, and randomized to rcGM-CSF or saline (placebo) given s.c. daily for 9 weeks. Within each stage and when all of the stages were combined, there was no difference between the treatment groups. In both studies, stage I COM is associated with a better prognosis. No effect on survival was observed with regard to tumor location in the oral cavity, sex, type/extent of surgery, or age. In a subset of dogs tested, pulmonary alveolar macrophage cytotoxicity was enhanced with combined rcGM-CSF and L-MTP-PE but not in dogs treated with L-MTP-PE alone. The present study indicates that after surgery, L-MTP-PE administered alone or combined with rcGM-CSF showed no significant antitumor activity in treating advanced stage COM. In early stage COM, L-MTP-PE was shown to result in a prolongation of ST. Furthermore, this study provides additional rationale for the use of the dog model for human malignant melanoma.

Acetylmuramyl-Alanyl-Isoglutamine↗

Computed tomographic evaluation of radiation pneumonitis in a canine model.

The objective of this study was to document the utility of computed tomography (CT) and a three-dimensional (3-D) radiotherapy treatment planning system for assessing the development of acute radiation pneumonitis in a canine model. Fourteen dogs were randomly assigned to a nonirradiated control group or one of three radiation dose groups receiving a single fraction of either 12, 15, or 18 Gy delivered to two-thirds of the right hemithorax. CT and survey radiographs were performed in all dogs prior to and at defined intervals for up to 13 weeks following irradiation. All images were subjectively evaluated for development of radiation pneumonitis and CT images were quantitatively analyzed. Radiation pneumonitis was detected earlier with CT images than with radiographs. Quantitatively, functional lung volume and radiation pneumonitis lesion volume on CT images changed over time in all irradiated dogs. However, there was no statistically significant difference between the three radiation dose groups, but a marked difference between irradiated dogs and nonirradiated controls. These data suggest that CT is superior to survey radiography for the evaluation and quantification of acute radiation pneumonitis in this canine model. Quantification of acute radiation pneumonitis suggests future promise for evaluating the efficacy of modifiers to lessen the effects of irradiating normal lung tissue in this canine model.

Acute Disease↗

Preclinical evaluation of a sterically stabilized liposome-encapsulated cisplatin in clinically normal cats.

OBJECTIVE: To evaluate the effects of administration of a sterically stabilized liposome-encapsulated cisplatin (SSL-CDDP) to cats. ANIMALS: 4 clinically normal cats. PROCEDURE: 2 of the cats were given multiple i.v. injections of SSL-CDDP at a dosage of 70 mg of free CDDP equivalent/m2 of body surface area at 3-week intervals. The other 2 cats received single i.v. injections of identical liposome preparations not containing CDDP. Vital signs; appetite; attitude; hematologic, serum biochemical, and urinalysis findings; and thoracic radiographic views were evaluated at predetermined intervals. RESULTS: Sterically stabilized liposome-encapsulated cisplatin was well tolerated by all cats. The only significant alterations in measured variables were an increase in serum cholesterol concentration 2 days after injection, and repeatable pyrexia in the cats receiving SSL-CDDP that began 10 to 12 hours after injection and continued for 18 hours, peaking at 40.5 to 41 C. Alterations in rectal temperature were not significant in cats receiving empty liposome vehicle. CONCLUSIONS: SSL-CDDP appears to be safe to administer to cats at a dosage of 70 mg of free CDDP equivalent/m2, a CDDP dose known to be therapeutic in dogs. Pyrexia, although marked, appears to be a short-term and well tolerated side effect. CLINICAL RELEVANCE: SSL-CDDP appears to abrogate the uniformly fatal side effects associated with administration of tumoricidal quantities of free CDDP to cats. This new formulation should allow investigation of the antitumor properties of CDDP against spontaneously arising neoplasms in cats.

Animals↗

Efficacy of pyridoxine to ameliorate the cutaneous toxicity associated with doxorubicin containing pegylated (Stealth) liposomes: a randomized, double-blind clinical trial using a canine model.

A cutaneous reaction termed palmar-plantar erythrodysesthesia (PPES) or hand-foot syndrome can be dose limiting for Doxil, a doxorubicin containing pegylated (Stealth) liposome. The objective of this study was to determine the ability of concomitant pyridoxine therapy to prevent the development of PPES during Doxil therapy. Forty-one dogs with non-Hodgkin's lymphoma were randomized in a double-blind fashion to receive either oral pyridoxine or placebo daily during Doxil chemotherapy (1.0 mg/kg, i.v., every 3 weeks for a total of five treatments). Cutaneous toxicity was determined by clinical and histological scoring. No difference was observed in remission rates (71.4 versus 75%) achieved between groups. The likelihood of developing serious PPES and having to decrease or discontinue Doxil therapy was 4.2 times (relative risk) greater in placebo group dogs than in pyridoxine group dogs (P = 0.032). Pyridoxine did not completely abrogate PPES; however, it occurred later and less dramatically than in placebo-treated dogs and resulted in fewer treatment delays or discontinuations, allowing a higher cumulative dose of Doxil to be received. Compared to the 5.0 mg/kg cumulative target dose, pyridoxine-treated dogs received a median cumulative dose of 4.7 mg/kg (mean, 4.1 mg/kg), and the placebo-treated dogs received a median of 2.75 mg/kg (mean, 2.9 mg/kg; P < 0.028). A trend (P = 0.084) toward prolongation of remission length was observed in dogs receiving pyridoxine, which was likely attributable to their ability to receive more Doxil without delay or discontinuation. We conclude that pyridoxine is effective in delaying the onset and severity of PPES in this canine model.

Animals↗

Preclinical trial of doxorubicin entrapped in sterically stabilized liposomes in dogs with spontaneously arising malignant tumors.

PURPOSE: To prospectively evaluate the short-term toxicoses associated with pegylated-liposomal doxorubicin (Doxil) administered to dogs with measurable tumors of various histologic types and sites. Preliminary information regarding efficacy was also generated. METHODS: A group of 51 dogs with histologically confirmed malignancies received a total of 103 Doxil treatments given i.v. every 3 weeks at dosages ranging from 0.75 to 1.1 mg/kg in the context of a phase I dose-escalation trial. Acute and short-term toxicities as well as tumor response and duration of response were characterized. RESULTS: The maximally tolerated dose in tumor-bearing dogs was established as 1.0 mg/kg i.v. every 3 weeks. The dose-limiting toxicity was a cutaneous toxicity clinically resembling palmar-plantar erythrodysesthesia (PPES). An overall response rate of 25.5% was observed with five complete responders and eight partial responders. CONCLUSIONS: Doxil appeared to be well tolerated at dosages similar to those tolerated for free doxorubicin in tumor-bearing dogs. PPES was the dose-limiting toxicity encountered, rather than myelosuppresion as is the case with free doxorubicin in dogs. Doxil as a single agent may have a broad spectrum of activity and deserves further evaluation.

Animals↗

Frequency of argyrophilic nucleolar organizer regions in fine-needle aspirates and biopsy specimens from mast cell tumors in dogs.

OBJECTIVE: To determine for mast cell tumors in dogs whether frequency of argyrophilic nucleolar organizer regions (AgNOR) determined by examining fine-needle aspirates (FNA) correlated with frequencies determined by examining biopsy specimens or with histologic grade. DESIGN: Case series. ANIMALS: 25 dogs with 32 histologically confirmed tumors. PROCEDURE: Biopsy specimens and FNA were collected from each tumor. Histologic grade and AgNOR frequency were determined. RESULTS: Frequency of AgNOR in FNA was significantly correlated with frequency in biopsy specimens and was significantly associated with histologic grade of the tumor. CLINICAL IMPLICATIONS: Determining AgNOR frequency in FNA of mast cell tumors in dogs is a rapid, minimally invasive means of obtaining information that potentially could be used to help predict biological behavior of the tumor and to guide clinicians and owners in making decisions about further diagnostic tests and treatment.

Animals↗

Evaluation of dogs and cats with tumors of the ear canal: 145 cases (1978-1992).

OBJECTIVE: To characterize the frequency, clinical signs, biologic behavior, and response to treatment of tumors of the ear canal in dogs and cats. DESIGN: Retrospective analysis of medical records. ANIMALS: Medical records of 81 dogs (48 malignant tumors, 33 benign tumors) and 64 cats (56 malignant tumors, 8 benign tumors). PROCEDURE: Data were analyzed for cats and dogs with malignant tumors, and risk factors were analyzed for their potential impact on survival time. RESULTS: Malignant tumor types most commonly reported included ceruminous gland adenocarcinoma, squamous cell carcinoma, and carcinoma of undetermined origin. Median survival time of dogs with malignant aural tumors was > 58 months, whereas that of cats was 11.7 months. A poor prognosis was indicated by extensive tumor involvement (dogs) and by neurologic signs at time of diagnosis, diagnosis of squamous cell carcinoma or carcinoma of undetermined origin, and invasion into lymphatics or blood vessels (cats). CLINICAL IMPLICATIONS: Malignant tumors of the ear canal in dogs and cats have a propensity for local invasion, but tend not to metastasize. Squamous cell carcinoma and carcinoma of undetermined origin were the most locally aggressive tumors. Malignant tumors of the ear canal are best managed by aggressive surgical excision. Radiotherapy may be useful when tumors cannot be completely removed.

Adenocarcinoma↗

Assessment of potential doubling time (Tpot), argyrophilic nucleolar organizer regions (AgNOR), and proliferating cell nuclear antigen (PCNA) as predictors of therapy response in canine non-Hodgkin's lymphoma.

The predictive potential of several proliferation indices for therapeutic outcome was investigated in 55 dogs with spontaneously occurring non-Hodgkin's lymphoma (NHL). Indices included potential doubling time (Tpot), argyrophilic nucleolar organizer region (AgNOR) frequency, and proliferating cell nuclear antigen labeling index (PCNA-LI). All tumors were of intermediate- or high-grade histology as assessed by the Working Formulation, and all dogs presented with disease of advanced clinical stage. All tumors were treated with an identical chemotherapeutic protocol. Tpot determination by a bromodeoxyuridine (BrdU) delayed-biopsy technique was readily applied in the dog. AgNOR frequency and PCNA-LI were easily obtained from archival, formalin-fixed, paraffin-embedded canine tissues. When accounting for all other prognostic variables by employing multivariate analysis, Tpot (p=0.017), and AgNOR frequency (p=0.021), but not PCNA-LI, were predictive of first remission duration. AgNOR frequency (p=0.033) was also predictive of survival time, and the predictive potential of Tpot approached significance (p=0.076). We conclude that Tpot and AgNOR frequency can be used as predictors of outcome in dogs with NHL, and spontaneous NHL in the dog may have significant potential as a model for further characterization of the association between tumor cell kinetics and chemoresponsiveness.

Animals↗

Liposome-encapsulated muramyl tripeptide phosphatidylethanolamine for the treatment of feline mammary adenocarcinoma--a multicenter randomized double-blind study.

Forty cats with previously untreated, histologically confirmed mammary gland adenocarcinoma received a radical mastectomy of the affected mammary chain(s). All cats were stratified according to clinical stage and randomized to receive either weekly intravenous liposome-encapsulated muramyl tripeptide phosphatidylethanolamine or placebo (lipid-equivalent) for eight consecutive weeks in this double-blind study. Thirty-six of the 40 cats were available for follow-up. No significant differences in either disease-free interval or survival were found as a result of treatment. Cats with clinical stage II disease had a statistically significantly longer disease-free interval (p < 0.02), and overall survival (p < 0.005) when compared with clinical stage III cats.

Acetylmuramyl-Alanyl-Isoglutamine↗