The tonotopically organized hearing organs of bushcrickets provide the opportunity for a detailed correlation of morphological and structural properties within hearing organs that are needed to ...establish tonotopic gradients. In the present study of a tonotopic insect hearing organ, we combine mechanical measurements of sound‐induced hearing organ motion and detailed anatomical investigations to explore the anatomical basis of tonotopy. We compare mechanical data of frequency responses along the auditory organ to several anatomical parameters. Low frequency responses are related to larger organ and cap cell size in the proximal part of the hearing organ while in the distal part of the organ, small organ and cap cell size is related to high‐frequency representation. However, the correlation between organ and cap cell size with continuous frequency representation along the organ is not very tight. Instead, the height of the organ and the corresponding length of the sensory dendrites are best correlated to tonotopic frequency representation. The sensory dendrite contains a ciliary root with a pronounced cross‐banding of electron‐dense material that should be important for the stiffness of the dendrite. The geometry of surrounding structures like the hemolymph channel and the acoustic trachea as well as the extension of the tectorial membrane are not correlated to the tonotopy. We provide evidence that tonotopy in the bushcricket hearing organ may depend on the size of ciliary structures. In particular, the ciliary root of the sensory cells is a likely cellular basis of tonotopy.
The height of the hearing organ and the corresponding length of the sensory dendrites are best correlated to tonotopic frequency representation. The sensory dendrite contains a ciliary root with a pronounced cross‐banding of electron‐dense material that could be important for the stiffness of the dendrite. Thus, the ciliary root of the sensory cells is likely the cellular basis of mechanical tonotopy.
Abstract BRAF V600E mutations have been reported in several histiocytic and dendritic cell neoplasms. In this case series, we report BRAF V600E–positive histiocytic and dendritic cell neoplasms in ...association with lymphomas and lymphoid proliferations. This is a review of cases with immunohistochemistry for BRAF V600E, with additional immunohistochemistry to categorize tumors. We report the first case of BRAF V600E–positive indeterminate cell tumor in association with angioimmunoblastic T-cell lymphoma. We also report a case of BRAF V600E–positive interdigitating dendritic cell sarcoma in a patient with positive B-cell polymerase chain reaction. It is unclear if these neoplasms developed as transdifferentiation of lymphoid neoplasms or if they developed independently. These cases illustrate the expanding spectrum of BRAF V600E–positive histiocytic and dendritic cell tumors and suggest that attention should be paid to lymphomas for possible coincident presentation of these disorders.
Chronic myeloproliferative neoplasms (MPN) are clonal disorders of hematopoietic stem cells, which fall into distinct categories based on a number of characteristics including the presence of the ...BCR-ABL1 gene fusion (chronic myelogenous leukemia) or the JAK2(V617F) mutation (polycythemia vera, primary myelofibrosis, and essential thrombocythemia). One of the criteria in the 2008 World Health Organization Classification divides MPN into different categories based on the presence of an underlying genetic abnormality, however the WHO does not currently address the classification of myeloproliferative neoplasms that have more than one genetic abnormality. The coexistence of a JAK2(V617F) mutation and BCR-ABL1 is rare, and to our knowledge, less than 25 cases have been reported in the literature. Our case series examines the clinical, histopathologic, and genetic features of 3 patients with myeloproliferative neoplasms characterized by concomitant BCR-ABL1 and JAK2(V617F). The implications for diagnosis and treatment of patients with concomitant BCR-ABL1 and JAK2(V617F) are discussed as well as how the BCR-ABL1 and JAK2(V617F)-positive clones may be related to one another.
Aggressive histiocytic lesions are uncommon in the pediatric population. These neoplasms occur in isolation or after therapy for other types of hematopoietic malignancy such as T-cell acute ...lymphoblastic leukemia. The etiology of these lesions is poorly understood, and no definitive standard of care has been established for patients with these diagnoses. Here, we report the success of thalidomide treatment for 2 subtypes of histiocytic proliferation--metastatic histiocytic sarcoma and extracutaneous juvenile xanthogranuloma--in pediatric patients. Our findings highlight the importance of considering thalidomide therapy in this unique and difficult to treat patient population.
Convergent evolution has led to surprising functional and mechanistic similarities between the vertebrate cochlea and some katydid ears 1,2. Here we report on an ‘auditory fovea’ (Figure 1A) in the ...duetting katydid Ancylecha fenestrata (Tettigoniidae). The auditory fovea is a specialized inner-ear region with a disproportionate number of receptor cells tuned to a narrow frequency range, and has been described in the cochlea of some vertebrates, such as bats and mole rats 3,4. In tonotopically organized ears, the location in the hearing organ of the optimal neuronal response to a tone changes gradually with the frequency of the stimulation tone. However, in the ears of A. fenestrata, the sensory cells in the auditory fovea are tuned to the dominant frequency of the female call; this area of the hearing organ is extensively expanded in males to provide an overrepresentation of this behaviorally important auditory input. Vertebrates developed an auditory fovea for improved prey or predator detection. In A. fenestrata, however, the foveal region facilitates acoustic pair finding, and the sexual dimorphism of sound-producing and hearing organs reflects the asymmetry in the mutual communication system between the sexes (Figures 1B, S1).
Scherberich et al. report on a pronounced auditory fovea as sex-specific adaptation of the hearing organ in a duetting katydid. The area of the ear that is tuned to the dominant frequency of the female call is extensively expanded in males and provides an overrepresentation of behaviorally important auditory input to facilitate mate finding.
From mammals to insects, acoustic communication is in many species crucial for successful reproduction. In the duetting bushcricket Ancylecha fenestrata, the mutual acoustic communication between ...males and females is asymmetrical. We investigated how those signalling disparities are reflected by sexual dimorphism of their ears. Both sexes have tympanic ears in their forelegs, but male ears possess a significantly longer crista acustica containing 35% more scolopidia. With more sensory cells to cover a similar hearing range, the male hearing organ shows a significantly expanded auditory fovea that is tuned to the dominant frequency of the female reply to facilitate phonotactic mate finding. This sex-specific auditory fovea is demonstrated in the mechanical and neuronal responses along the tonotopically organized crista acustica by laservibrometric and electrophysiological frequency mapping, respectively. Morphometric analysis of the crista acustica revealed an interrupted gradient in organ height solely within this auditory fovea region, whereas all other anatomical parameters decrease continuously from proximal to distal. Combining behavioural, anatomical, biomechanical and neurophysiological information, we demonstrate evidence of a pronounced auditory fovea as a sex-specific adaptation of an insect hearing organ for intraspecific acoustic communication.
From mammals to insects, acoustic communication is in many species crucial for successful reproduction. In the duetting bushcricket Ancylecha fenestrata, the mutual acoustic communication between ...males and females is asymmetrical. We investigated how those signalling disparities are reflected by sexual dimorphism of their ears. Both sexes have tympanic ears in their forelegs, but male ears possess a significantly longer crista acustica containing 35% more scolopidia. With more sensory cells to cover a similar hearing range, the male hearing organ shows a significantly expanded auditory fovea that is tuned to the dominant frequency of the female reply to facilitate phonotactic mate finding. This sex-specific auditory fovea is demonstrated in the mechanical and neuronal responses along the tonotopically organized crista acustica by laservibrometric and electrophysiological frequency mapping, respectively. Morphometric analysis of the crista acustica revealed an interrupted gradient in organ height solely within this auditory fovea region, whereas all other anatomical parameters decrease continuously from proximal to distal. Combining behavioural, anatomical, biomechanical and neurophysiological information, we demonstrate evidence of a pronounced auditory fovea as a sex-specific adaptation of an insect hearing organ for intraspecific acoustic communication.
Currently, it is unusual to combine evaluation for vertebral fracture with measurement of bone mineral density in clinical practice. Using Quantitative Morphometric Vertebral Analysis (Instant ...Vertebral Assessment IVA) in our existing Mobile Dual-Energy X-Ray Absorptiometry (DXA) Program, we implemented a testing procedure that examined 5 different IVA protocols focusing on clinical utility and cost. Using small-scale tests of change (PDSA cycles), data from the preceding cycle drives the development of the next cycle. In this article, we describe the process and rationale for selecting patients for the IVA study. In addition, we review the literature on vertebral fracture assessment using DXA and emphasize the clinical utility of point of service testing by providing the needed knowledge for best patient care by simultaneous DXA and IVA testing. The application of this new technology increased identification of the high-risk patient by 11%, with a nominal additional cost per DXA study of $14. This study provides a useful framework for the integration of IVA into a clinical DXA program.
Mechanoelectrical transduction of acoustic signals is the fundamental process for hearing in all ears across the animal kingdom. Here, we performed in vivo laser-vibrometric and electrophysiological ...measurements at the transduction site in an insect ear (Mecopoda elongata) to relate the biomechanical tonotopy along the hearing organ to the frequency tuning of the corresponding sensory cells. Our mechanical and electrophysiological map revealed a biomechanical filter process that considerably sharpens the neuronal response. We demonstrate that the channel gating, which acts on chordotonal stretch receptor neurons, is based on a mechanical directionality of the sound-induced motion. Further, anatomical studies of the transduction site support our finding of a stimulus-relevant tilt. In conclusion, we were able to show, in an insect ear, that directionality of channel gating considerably sharpens the neuronal frequency selectivity at the peripheral level and have identified a mechanism that enhances frequency discrimination in tonotopically organized ears.
Processing of complex signals in the hearing organ remains poorly understood. This paper aims to contribute to this topic by presenting investigations on the mechanical and neuronal response of the ...hearing organ of the tropical bushcricket species Mecopoda elongata to simple pure tone signals as well as to conspecific song as a complex acoustic signal. The high-frequency hearing organ of bushcrickets, the crista acustica (CA), is tonotopically tuned to frequencies between about 4 and 70 kHz. Laser Doppler vibrometer measurements revealed a strong and dominant low-frequency-induced motion of the CA when stimulated with either pure tone or complex stimuli. Consequently, the high-frequency distal area of the CA is more strongly deflected by low-frequency-induced waves than by high-frequency-induced waves. This low-frequency dominance will have strong effects on the processing of complex signals. Therefore, we additionally studied the neuronal response of the CA to native and frequency-manipulated chirps. Again, we found a dominant influence of low-frequency components within the conspecific song, indicating that the mechanical vibration pattern highly determines the neuronal response of the sensory cells. Thus, we conclude that the encoding of communication signals is modulated by ear mechanics.
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