Fibroblast Activation Protein Triggers Release of Drug Payload from Non-internalizing Small Molecule Drug Conjugates in Solid Tumors

PURPOSE

Small molecule drug conjugates (SMDC) are modular anticancer prodrugs that include a tumor-targeting small organic ligand, a cleavable linker, and a potent cytotoxic agent. Most of the SMDC products that have been developed for clinical applications target internalizing tumor-associated antigens on the surface of tumor cells. We have recently described a novel non-internalizing small organic ligand (named OncoFAP) of fibroblast activation protein (FAP), a tumor-associated antigen highly expressed in the stroma of most solid human malignancies.

EXPERIMENTAL DESIGN

In this article, we describe a new series of OncoFAP-Drug derivatives based on monomethyl auristatin E (MMAE; a potent cytotoxic tubulin poison) and dipeptide linkers that are selectively cleaved by FAP in the tumor microenvironment.

RESULTS

The tumor-targeting potential of OncoFAP was confirmed in patients with cancer using nuclear medicine procedures. We used mass spectrometry methodologies to quantify the amount of prodrug delivered to tumors and normal organs, as well as the efficiency of the drug release process. Linkers previously exploited for anticancer drug conjugates were used as benchmark. We identified OncoFAP-Gly-Pro-MMAE as the best performing SMDC, which has now been prioritized for further clinical development. OncoFAP-Gly-Pro-MMAE selectively delivered more than 10% injected dose per gram of MMAE to FAP-positive tumors, with a tumor-to-kidney ratio of 16:1 at 24 hours post-injection.

CONCLUSIONS

The FAP-specific drug conjugates described in this article promise to be efficacious for the targeting of human malignancies. The extracellular release of potent anticancer payloads mediates durable complete remission in difficult-to-treat animal models of cancer.

Mass Spectrometry-Based Method for the Determination of the Biodistribution of Tumor-Targeting Small Molecule-Metal Conjugates

Nuclear medicine plays a key role in modern diagnosis and cancer therapy. The development of tumor-targeting radionuclide conjugates (also named small molecule-radio conjugates (SMRCs)) represents a significant improvement over the clinical use of metabolic radiotracers (e.g., [¹⁸F]-fluorodeoxyglucose) for imaging and over the application of biocidal external beam radiations for therapy. During the discovery of SMRCs, molecular candidates must be carefully evaluated typically by performing biodistribution assays in preclinical tumor models. Quantification methodologies based on radioactive counts are typically demanding due to safety concerns, availability of radioactive materials, and infrastructures. In this article, we report the development of a mass spectrometry (MS)-based method for the detection and quantification of small molecule-metal conjugates (SMMCs) as cold surrogates of SMRCs. We applied this methodology for the evaluation of the biodistribution of a particular class of tumor-targeting drug candidates based on ^natLu, ^natGa, and ^natF and directed against fibroblast activation protein (FAP). The reliability of the liquid chromatography-MS (LC-MS) analysis was validated by a direct comparison of MS-based and radioactivity-based biodistribution data. The results show that MS biodistribution of stable isotope metal conjugates is an orthogonal tool for the preclinical characterization of different classes of radiopharmaceuticals.

Abstract LB522: Fibroblast activation protein triggers the release of drug payload from non-internalizing small molecule-drug conjugates in solid tumors

Small Molecule-Drug Conjugates (SMDCs) are modular anti-cancer pro-drugs that include a tumor-targeting small ligand, a cleavable linker and a potent cytotoxic agent. SMDC products that have been developed for clinical applications are targeting internalizing tumor-associated antigens expressed on the surface of tumor cells. We have recently developed a novel non-internalizing small organic ligand (named OncoFAP) of Fibroblast Activation Protein (FAP), a tumor-associated antigen highly expressed in the stroma of most of solid human malignancies. The tumor targeting performance of OncoFAP has been validated by nuclear medicine studies in patients with various solid tumors. In a previous study, we showed that OncoFAP can be used to produce non-internalizing SMDCs that are effective and well tolerated. Here, we describe a new series of OncoFAP-Drug derivatives based on the MMAE tubulin poison and dipeptide linkers that are selectively cleaved by FAP in the tumor microenvironment. We benchmarked the new SMDCs against OncoFAP-MMAE conjugates displaying linker modules which are widely used in approved and clinical stage Antibody-Drug Conjugates, including structures cleaved by Cathepsin B and by reducing agents. We selected OncoFAP-GlyPro-MMAE as the most efficacious and safe SMDC for further clinical development after quantitatively analyzing the biodistribution of MMAE released by OncoFAP-MMAE conjugates. OncoFAP-GlyPro-MMAE selectively delivers high amounts of MMAE at the site of disease, with a tumor-to-kidney ratio of 7-to-1 and of 16-to-1 at 6- and 24-hours post-injection, respectively. Our molecules based on the OncoFAP tumor-targeting ligand and FAP-cleavable linkers promise to be safe and effective against most of human malignancies.

Citation Format: Aureliano Zana, Andrea Galbiati, Ettore Gilardoni, Jacopo Millul, Theo Sturm, Riccardo Stucchi, Matilde Bocci, Abdullah Elsayed, Lisa Nadal, Martina Cirillo, Dario Neri, Samuele Cazzamalli. Fibroblast activation protein triggers the release of drug payload from non-internalizing small molecule-drug conjugates in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB522.

Mild Acid Elution and MHC Immunoaffinity Chromatography Reveal Similar Albeit Not Identical Profiles of the HLA Class I Immunopeptidome

To understand and treat immunology-related diseases, a comprehensive, unbiased characterization of major histocompatibility complex (MHC) peptide ligands is of key importance. Preceding the analysis by mass spectrometry, MHC class I peptide ligands are typically isolated by MHC immunoaffinity chromatography (MHC-IAC) and less often by mild acid elution (MAE). MAE may provide a cheap alternative to MHC-IAC for suspension cells but has been hampered by the high number of contaminating, MHC-unrelated peptides. Here, we optimized MAE, yielding MHC peptide ligand purities of more than 80%. When compared with MHC-IAC, obtained peptides were similar in numbers, identities, and to a large extent intensities, while the percentage of cysteinylated peptides was 5 times higher in MAE. The latter benefitted the discovery of MHC-allotype-specific, distinct cysteinylation frequencies at individual positions of MHC peptide ligands. MAE revealed many MHC ligands with unmodified, N-terminal cysteine residues which get lost in MHC-IAC workflows. The results support the idea that MAE might be particularly valuable for the high-confidence analysis of post-translational modifications by avoiding the exposure of the investigated peptides to enzymes and reactive molecules in the cell lysate. Our improved and carefully documented MAE workflow represents a high-quality, cost-effective alternative to MHC-IAC for suspension cells.

T cell recognition of novel shared breast cancer antigens is frequently observed in peripheral blood of breast cancer patients

Advances within cancer immunotherapy have fueled a paradigm shift in cancer treatment, resulting in increasing numbers of cancer types benefitting from novel treatment options. Despite originally being considered an immunologically silent malignancy, recent studies encourage the research of breast cancer immunogenicity to evaluate immunotherapy as a treatment strategy. However, the epitope landscape in breast cancer is minimally described, limiting the options for antigen-specific, targeted strategies. Aromatase, never in mitosis A-related kinase 3 (NEK3), protein inhibitor of activated STAT3 (PIAS3), and prolactin are known as upregulated proteins in breast cancer. In the present study, these four proteins are identified as novel T cell targets in breast cancer. From the four proteins, 147 peptides were determined to bind HLA-A*0201 and -B*0702 using a combined in silico/in vitro affinity screening. T cell recognition of all 147 peptide-HLA-A*0201/-B*0702 combinations was assessed through the use of a novel high-throughput method utilizing DNA barcode labeled multimers. T cell recognition of sequences within all four proteins was demonstrated in peripheral blood of patients, and significantly more T cell responses were detected in patients compared to healthy donors for both HLA-A*0201 and -B*0702. Notably, several of the identified responses were directed toward peptides, with a predicted low or intermediate binding affinity. This demonstrates the importance of including low-affinity binders in the search for epitopes within shared tumor associated antigens (TAAs), as these might be less subject to immune tolerance mechanisms. The study presents four novel TAAs containing multiple possible targets for immunotherapy of breast cancer.

#EUROmicroMOOC: using Twitter to share trends in Microbiology worldwide

Twitter is one of the most popular social media networks that, in recent years, has been increasingly used by researchers as a platform to share science and discuss ongoing work. Despite its popularity, Twitter is not commonly used as a medium to teach science. Here, we summarize the results of #EUROmicroMOOC: the first worldwide Microbiology Massive Open Online Course taught in English using Twitter. Content analytics indicated that more than 3 million users saw posts with the hashtag #EUROmicroMOOC, which resulted in over 42 million Twitter impressions worldwide. These analyses demonstrate that free Microbiology MOOCs shared on Twitter are valuable educational tools that reach broad audiences throughout the world. We also describe our experience teaching an entire Microbiology course using Twitter and provide recommendations when using social media to communicate science to a broad audience.

Antibody-Based Delivery of Cytokine Payloads to Carbonic Anhydrase IX Leads to Cancer Cures in Immunocompetent Tumor-Bearing Mice

Antibody-cytokine fusion proteins can have the potential to increase the density and activity of subsets of leukocytes within the tumor mass. Here, we describe the design, production, and characterization of four novel antibody-cytokine fusion proteins directed against human carbonic anhydrase IX, a highly validated marker of hypoxia that is overexpressed in clear cell renal cell carcinoma and other malignancies. As immunomodulatory payloads we used TNF, IL2, IFNα2 (corresponding to products that are in clinical use), and IL12 (as this cytokine potently activates T cells and NK cells). Therapy experiments were performed in BALB/c mice, bearing CT26 tumors transfected with human carbonic anhydrase IX, in order to assess the performance of the fusion proteins in an immunocompetent setting. The biopharmaceuticals featuring TNF, IL2, or IL12 as payloads cured all mice in their therapy groups, whereas only a subset of mice was cured by the antibody-based delivery of IFNα2. Although the antibody fusion with TNF mediated a rapid hemorrhagic necrosis of the tumor mass, a slower regression of the neoplastic lesions (which continued after the last injection) was observed with the other fusion proteins, and treated mice acquired protective anticancer immunity. A high proportion of tumor-infiltrating CD8⁺ T cells was specific to the retroviral antigen AH1; however, the LGPGREYRAL peptide derived from human carbonic anhydrase IX was also present on tumor cells. The results described herein provide a rationale for the clinical use of fully human antibody-cytokine fusions specific to carbonic anhydrase IX.

A cross-sectional study on preoperative anxiety in adults

OBJECTIVE

The main objective of this study was a detailed comparison of the level of anxiety about surgery and anesthesia. Other objectives included the assessment of the prevalence and intensity of preoperative anxiety.

METHODS

This cross-sectional single-center survey used the validated Amsterdam anxiety and information scale (APAIS) and a modified numeric rating scale (mNRS) to assess preoperative anxiety, anxiety about surgery and anxiety about anesthesia. Prevalences and intensities of anxieties were predominantly analyzed descriptively.

RESULTS

3200 patients were enrolled and 3087 (57% females) were analyzed. 92.6% reported preoperative anxiety according to APAIS scores. The average total APAIS anxiety score (APAIS-A-T) was 9.9 (SD 3.6). 40.5% reported high anxiety (defined as APAIS-A-T > 10). Mean anxiety about surgery (APAIS-A-Su) was higher than mean anxiety about anesthesia (APAIS-A-An): 5.5 (SD 2.1) vs. 4.3 (SD 1.9), p < 0.0001. Accordingly, more patients were substantially more afraid (score difference > 2) of surgery (642, 20.8%, 95% CI 19.4-22.3) than of anesthesia (48, 1.6%, 95% CI 1.2-2.1).

CONCLUSION

Preoperative anxiety is still very common among adult patients scheduled to undergo an elective procedure. Therefore, it should be evaluated routinely. Anxiety about surgery and anxiety about anesthesia differ in many patients. For this reason, anxiety about surgery and anxiety about anesthesia should be assessed separately. This would allow providing a more individualized support of patients to cope with their anxiety and could require particular attention by the surgeon or the anesthetist.

Minimal Information About an Immuno-Peptidomics Experiment (MIAIPE)

Minimal information about an immuno-peptidomics experiment (MIAIPE) is an initiative of the members of the Human Immuno-Peptidome Project (HIPP), an international program organized by the Human Proteome Organization (HUPO). The aim of the MIAIPE guidelines is to deliver technical guidelines representing the minimal information required to sufficiently support the evaluation and interpretation of immunopeptidomics experiments. The MIAIPE document has been designed to report essential information about sample preparation, mass spectrometric measurement, and associated mass spectrometry (MS)-related bioinformatics aspects that are unique to immunopeptidomics and may not be covered by the general proteomics MIAPE (minimal information about a proteomics experiment) guidelines.

Characterization of the Canine MHC Class I DLA-88*50101 Peptide Binding Motif as a Prerequisite for Canine T Cell Immunotherapy

There are limitations in pre-clinical settings using mice as a basis for clinical development in humans. In cancer, similarities exist between humans and dogs; thus, the dog patient can be a link in the transition from laboratory research on mouse models to clinical trials in humans. Knowledge of the peptides presented on MHC molecules is fundamental for the development of highly specific T cell-based immunotherapies. This information is available for human MHC molecules but is absent for the canine MHC. In the present study, we characterized the binding motif of dog leukocyte antigen (DLA) class I allele DLA-88*50101, using human C1R and K562 transfected cells expressing the DLA-88*50101 heavy chain. MHC class I immunoaffinity-purification revealed 3720 DLA-88*50101 derived peptides, which enabled the determination of major anchor positions. The characterized binding motif of DLA-88*50101 was similar to HLA-A*02:01. Peptide binding analyses on HLA-A*02:01 and DLA-88*50101 via flow cytometry showed weak binding of DLA-88*50101 derived peptides to HLA-A*02:01, and vice versa. Our results present for the first time a detailed peptide binding motif of the canine MHC class I allelic product DLA-88*50101. These data support the goal of establishing dogs as a suitable animal model for the evaluation and development of T cell-based cancer immunotherapies, benefiting both dog and human patients.

Analysis of Major Histocompatibility Complex (MHC) Immunopeptidomes Using Mass Spectrometry

The myriad of peptides presented at the cell surface by class I and class II major histocompatibility complex (MHC) molecules are referred to as the immunopeptidome and are of great importance for basic and translational science. For basic science, the immunopeptidome is a critical component for understanding the immune system; for translational science, exact knowledge of the immunopeptidome can directly fuel and guide the development of next-generation vaccines and immunotherapies against autoimmunity, infectious diseases, and cancers. In this mini-review, we summarize established isolation techniques as well as emerging mass spectrometry-based platforms (i.e. SWATH-MS) to identify and quantify MHC-associated peptides. We also highlight selected biological applications and discuss important current technical limitations that need to be solved to accelerate the development of this field.

An open-source computational and data resource to analyze digital maps of immunopeptidomes

We present a novel mass spectrometry-based high-throughput workflow and an open-source computational and data resource to reproducibly identify and quantify HLA-associated peptides. Collectively, the resources support the generation of HLA allele-specific peptide assay libraries consisting of consensus fragment ion spectra, and the analysis of quantitative digital maps of HLA peptidomes generated from a range of biological sources by SWATH mass spectrometry (MS). This study represents the first community-based effort to develop a robust platform for the reproducible and quantitative measurement of the entire repertoire of peptides presented by HLA molecules, an essential step towards the design of efficient immunotherapies.

DOI:http://dx.doi.org/10.7554/eLife.07661.001

The cells of the immune system protect us by recognizing telltale molecules produced by damaged and diseased cells, or by infection-causing microorganisms (which are also called pathogens). To help with this process, the cells in our bodies display small fragments of proteins (called peptides) on their surface that are then checked by the immune cells. Collectively, these peptides are referred to as the ‘immunopeptidome’, and deciphering the complexity of the human immunopeptidome is important for both basic research and medical science. Such an achievement would help to guide the development of next-generation vaccines and therapies against autoimmune disorders, infectious diseases and cancers.

In the past, immune peptides were mostly identified using a technique that is commonly called ‘shotgun’ mass spectrometry. However, this approach doesn't always provide reproducible results. In 2012, researchers reported the development of a new approach—which they called ‘SWATH’ mass spectrometry—that could yield more reproducible data.

Now, Caron et al.—including many of the researchers involved in the 2012 study—have developed a large collection of standardized tests that use SWATH mass spectrometry to analyze the human immunopeptidome. The workflow and the computational and data resources developed as part of this international effort are the first steps toward highly reproducible and measurable analyses of the immunopeptidome across many samples. Moreover, the large repository of assays generated by the project has been made public and will serve a large community of researchers, which should enable better collaborations.

In the future, SWATH mass spectrometry could be used as a robust technology for the reproducible detection and measurement of pathogen-specific or cancer-specific immune peptides. This could greatly help in the design of personalized immune-based therapies.

DOI:http://dx.doi.org/10.7554/eLife.07661.002

Of volatiles and peptides: in search for MHC-dependent olfactory signals in social communication

Genes of the major histocompatibility complex (MHC), which play a critical role in immune recognition, are considered to influence social behaviors in mice, fish, humans, and other vertebrates via olfactory cues. As studied most extensively in mice, the polymorphism of MHC class I genes is considered to bring about a specific scent signature, which is decoded by the olfactory system resulting in an individual-specific reaction such as mating. On the assumption that this signature resides in volatiles, extensive attempts to identify these MHC-specific components in urine failed. Alternatively, it has been suggested that peptide ligands of MHC class I molecules are released into urine and can elicit an MHC-haplotype-specific behavioral response after uptake into the nose by sniffing. Analysis of the urinary peptide composition of mice shows that MHC-derived peptides are present, albeit in extremely low concentrations. In contrast, urine contains abundant peptides which differ between mouse strains due to genomic variations such as single-nucleotide variations or complex polymorphisms in multigene families as well as in their concentration. Thus, urinary peptides represent a real-time sampling of the expressed genome available for sensory evaluation. It is suggested that peptide variation caused by genomic differences contains sufficient information for individual recognition beyond or instead of an influence of the MHC in mice and other vertebrates.

Mouse urinary peptides provide a molecular basis for genotype discrimination by nasal sensory neurons

Selected groups of peptides, including those that are presented by major histocompatibility complex (MHC) proteins, have been proposed to transmit information to the olfactory system of vertebrates via their ability to stimulate chemosensory neurons. However, the lack of knowledge about such peptides in natural sources accessible for nasal recognition has been a major barrier for this hypothesis. Here we analyse urinary peptides from selected mouse strains with respect to genotype-related individual differences. We discover many abundant peptides with single amino-acid variations corresponding to genomic differences. The polymorphism of major urinary proteins is reflected by variations in prominent urinary peptides. We also demonstrate an MHC-dependent peptide (SIINFEKL) occurring at very low concentrations in mouse urine. Chemoreceptive neurons in the vomeronasal organ detect and discriminate single amino-acid variation peptides as well as SIINFEKL. Hence, urinary peptides represent a real-time sampling of the expressed genome available for chemosensory assessment by other individuals.

[Clinical-diagnostic hit rates and differential diagnoses depending on the sampling site of 2109 presumptively malignant canine and feline tumour submissions]

OBJECTIVE

The frequency of correct clinical presumptive diagnosis and the spectrum of important differential diagnoses were investigated in common canine and feline malignant tumours.

MATERIAL AND METHODS

Based on 2109 presumptive malignant tumour samples submitted to the Institute of Veterinary Pathology of the Justus-Liebig-University, Giessen, the hit rates of the presumed diagnoses of the submitting veterinarians and the actual histopathological diagnosis were calculated for the specific sampling sites. These hit rates were statistically evaluated for significant deviations between the different sampling sites using the chi-square test and Fisher's exact test. Additionally, the more common differential diagnoses with respect to the sampling site were established.

RESULTS

This compilation of histopathological diagnoses, with respect to the varying sampling sites, combined with the hit rates of the presumed diagnoses of the submitting veterinarians, yields quantitative knowledge on the frequency of occurrence, correct clinical diagnosis and macroscopic appearance of the malignant tumours investigated. The correctness of the presumptive clinical diagnosis largely depends on tumour type and localization. For the more frequent tumours, it varies from 19% to 83%.

CONCLUSION AND CLINICAL RELEVANCE

The results show the importance of a histopathological evaluation of all tumour samples as the presumptive clinical diagnosis based on appearance only corresponds in a few cases with the histopathological diagnosis.

Nichtinvasives erweitertes hämodynamisches Monitoring

BACKGROUND

Cardiac output and the cardiac index (CI) are not routinely monitored during major abdominal surgery for economic as well as medical reasons. This practice, however, might be changed by the application of newer non-invasive technologies like the partial CO(2) rebreathing method based on the inverse Fick's principle. In this prospective randomized study we investigated the impact of a non-invasive monitoring of CI on the incidence of hemodynamic instability and interventions by the attending anesthesiologist during major abdominal surgery.

PATIENTS AND METHODS

Additionally to routine hemodynamic monitoring we measured CI using the partial CO(2) rebreathing method in 28 patients (9 female, 19 male) undergoing major abdominal surgery. In group I the anesthesiologists were aware of the results of the extended hemodynamic monitoring and in group II the attending anesthesiologist was blinded to the information obtained by these measurements of CI.

RESULTS

Groups did not differ with regard to the baseline hemodynamic parameters. We obtained 923 measurements in both groups and 95 situations of hemodynamic instability (CI<2.5 l/minxm(2)) were detected in group I compared to 147 situations in group II (p<0.05). There were significantly more hemodynamic interventions in group I than in group II (p<0.0001). The cardiac index remained higher in group I in comparison to group II (p<0.0001). Measurement of CI was the only method to detect situations of hemodynamic instability in our setting.

CONCLUSION

The incidence of hemodynamic instability was significantly reduced during major abdominal surgery when anesthesiologists were aware of the measurement results of extended hemodynamic monitoring.

Medication use among children with asthma in East Harlem

PURPOSE

To examine daily use of antiinflammatory medication among children with asthma in East Harlem, where hospitalization rates for asthma are among the highest in the United States.

METHODS

We analyzed parent/guardian reports of medications used by children with current asthma (defined as physician diagnosis and wheezing during the previous 12 months) identified from a cross-sectional survey conducted in 2 elementary schools.

RESULTS

From an overall sample of 1319 children, 298 with current asthma were included in this analysis. Most of those with asthma were Puerto Rican (136 [46%]) or black (98 [33%]), 168 (57%) were boys, and the median age was 8 years old. Overall, 65 (22%) were using antiinflammatory medication on a daily basis. A subgroup of 107 children with asthma had been hospitalized during the previous 12 months or had used beta(2)-agonist on a daily basis, suggesting persistent or severe asthma. Of these 107 children, 42 (39%) were taking antiinflammatory medication on a daily basis. Multivariate analysis of these 107 children revealed that daily use of antiinflammatory medication was associated with using a spacer tube (adjusted odds ratio [AOR]: 3. 08; 95% confidence interval [CI]: 1.27,7.47) and having seen a physician in the past 6 months (AOR: 3.46; CI: 1.01,11.9). Compared with Puerto Ricans, blacks (AOR:.32; CI:.12,.89) or children of other races/ethnicities (AOR:.27; CI:.09,.85) were less likely to use antiinflammatory medication on a daily basis.

CONCLUSION

Daily use of antiinflammatory medication for children with persistent or severe asthma in East Harlem was underused. Differences in access to care may explain some findings; however, reasons for ethnic differences in use remain unclear. Both community interventions and additional provider education are needed.

[Chronic polyarthritis and carpal tunnel syndrome. Results of follow-up]

Between July 1974 and December 1989, carpal tunnel-syndromes (CTS) were operated on in 903 hands of 746 patients. 147 of these patients (191 hands) were suffering from chronic inflammatory joint diseases. In 11 patients CTS was the first sign of rheumatoid arthritis (R.A.). The hands showed intraoperatively in 44.8% (n = 86/191) an extensive tenosynovitis with an aggressive infiltration. In 19% (n = 36/191), we had to extend the obligate tenosynovectomy on the flexor tendon parts of the fingers and ligaments (28 hands). 21 articulosynovectomies on the wrist or finger joints were performed. In 6 hands (8.0%) tendon ruptures were repaired. A questionnaire was completed for 107 of 147 patients (72.8%) (with 145 operated hands). Clinical (77 hands) and electromyographical examinations (49 hands) were performed an average of 5.1 (0.7-15) years postoperatively. 20 patients (13.6%) died, 20 could not be traced. In 86% (n = 125/145) of the patients we achieved relief of pain and a marked reduction of neurological deficits. 96.3% of the patients were content. The improvement of function of the hand after surgical intervention is of a great benefit for the patient with R. A. The overall risks of the procedure are low (complications 14%; no recidivism). Therefore, we recommend surgery in early stages after a confirmed diagnosis or a reasonable suspicion.

Classical conditioning of aggressive display in Siamese fighting fish

Unconditioned aggressive-display behavior elicited by the mirror image of a male Siamese Fighting Fish was brought under the control of a previously ineffective stimulus by classical conditioning. A stimulus light repeatedly paired with mirror presentation came to elicit the complex aggressive-behavior sequence. Relative rates of acquisition of four components of the display were compared. Fin erection and undulating movements were acquired most rapidly while gill-cover erection and frontal approach were acquired most slowly. A discriminative conditioning procedure revealed that the response was specifically elicited by the conditioned stimulus, and not a sensitization artifact.