Exploring Pleiotropic Functions of Canine ß-Defensin 103: Nasal Cavity Expression, Antimicrobial Activity, and Melanocortin Receptor Activity.

Canine ß-defensin 103 (cBD103) and its common variant cBD103ΔG23 are multitasking polypeptides. As a ß-defensin, cBD103 is one of many antimicrobial agents used by the innate immunity to thwart pathogenic colonization. In this study, we showed that cBD103 was expressed throughout the nasal cavity, with primary expression in the nares as well as respiratory and olfactory epithelia. In the rostral nasal concha, cBD103 was expressed in the epithelium, and to a lesser degree in the lamina propria, but was absent in goblet cells. In the main olfactory epithelium, virtually all cells in the epithelial layer and select cells associated with Bowman's glands expressed cBD103. We also showed that the ΔG23 mutation did not appreciably alter the antimicrobial activity of the peptide against several species of microorganisms tested in nutrient-rich or minimal media or minimal media with salt added. Moreover, we showed antimicrobial activity in minimal media did not necessarily predict the inhibitory action of the peptide in nutrient-rich media. Both forms of cBD103 caused ultrastructural changes (membrane blebbing, condensation of intracellular contents and cell wall lysis) in Escherichia coli and Staphylococcus aureus. As a ligand of the melanocortin receptors, we showed that cBD103ΔG23 increased ERK1/2 activation and cAMP accumulation when bound to the human or canine melanocortin-4 receptor, acting as a weak allosteric agonist.

Is the Mole Rat Vomeronasal Organ Functional?

The colonial naked mole rat Heterocephalus glaber is a subterranean, eusocial rodent. The H. glaber vomeronasal organ neuroepithelium (VNE) displays little postnatal growth. However, the VNE remains neuronal in contrast to some mammals that possess nonfunctional vomeronasal organ remnants, for example, catarrhine primates and some bats. Here, we describe the vomeronasal organ (VNO) microanatomy in the naked mole rat and we make preliminary observations to determine if H. glaber shares its minimal postnatal VNE growth with other African mole rats. We also determine the immunoreactivity to the mitotic marker Ki67, growth-associated protein 43 (GAP43), and olfactory marker protein (OMP) in six adult and three subadult H. glaber individuals. VNE volume measurements on a small sample of Cryptomys hottentotus and Fukomys damarensis indicate that the VNE of those African mole rat species are also likely to be growth-deficient. Ki67(+) cells show that the sensory epithelium is mitotically active. GAP43 labelling indicates neurogenesis and OMP(+) cells are present though less numerous compared to GAP43(+) cells. In this respect, the VNO of H. glaber does not appear vestigial. The African mole rat VNE may be unusually variable, perhaps reflecting reduced selection pressure on the vomeronasal system. If so, African mole rats may provide a useful genetic model for understanding the morphological variability observed in the mammalian VNO. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc. Anat Rec, 303:318-329, 2020. © 2019 American Association for Anatomy.

PEGylation of zinc nanoparticles amplifies their ability to enhance olfactory responses to odorant.

Olfactory responses are intensely enhanced with the addition of endogenous and engineered primarily-elemental small zinc nanoparticles (NPs). With aging, oxidation of these Zn nanoparticles eliminated the observed enhancement. The design of a polyethylene glycol coating to meet storage requirements of engineered zinc nanoparticles is evaluated to achieve maximal olfactory benefit. The zinc nanoparticles were covered with 1000 g/mol or 400 g/mol molecular weight polyethylene glycol (PEG). Non-PEGylated and PEGylated zinc nanoparticles were tested by electroolfactogram with isolated rat olfactory epithelium and odorant responses evoked by the mixture of eugenol, ethyl butyrate and (±) carvone after storage at 278 K (5 oC), 303 K (30 oC) and 323 K (50 oC). The particles were analyzed by atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and laser Doppler velocimetry. Our data indicate that stored ZnPEG400 nanoparticles maintain physiologically-consistent olfactory enhancement for over 300 days. These engineered Nanoparticles support future applications in olfactory research, sensitive detection, and medicine.

Regulation of intracellular trafficking and secretion of adiponectin by myosin II.

Adiponectin is a protein secreted by white adipocytes that plays an important role in insulin action, energy homeostasis and the development of atherosclerosis. The intracellular localization and trafficking of GLUT4 and leptin in adipocytes has been well studied, but little is known regarding the intracellular trafficking of adiponectin. Recent studies have demonstrated that constitutive adiponectin secretion is dependent on PIP2 levels and the integrity of cortical F-actin. Non-muscle myosin II is an actin-based motor that is associated with membrane vesicles and participates in vesicular trafficking in mammalian cells. Therefore, we investigated the role of myosin II in the trafficking and secretion of adiponectin in 3T3-L1 adipocytes. Confocal microscopy revealed that myosin IIA and IIB were dispersed throughout the cytoplasm of the adipocyte. Both myosin isoforms were localized in the Golgi/TGN region as evidenced by colocalization with the cis-Golgi marker, p115 and the trans-Golgi marker, γ-adaptin. Inhibition of myosin II activity by blebbistatin or actin depolymerization by latrunculin B dispersed myosin IIA and IIB towards the periphery while significantly inhibiting adiponectin secretion. Therefore, the constitutive trafficking and secretion of adiponectin in 3T3-L1 adipocytes occurs by an actin-dependent mechanism that involves the actin-based motors, myosin IIA and IIB.

AAV-mediated gene delivery attenuates neuroinflammation in feline Sandhoff disease.

Sandhoff disease (SD) is a lysosomal storage disorder characterized by the absence of hydrolytic enzyme ß-N-acetylhexosaminidase (Hex), which results in storage of GM2 ganglioside in neurons and unremitting neurodegeneration. Neuron loss initially affects fine motor skills, but rapidly progresses to loss of all body faculties, a vegetative state, and death by five years of age in humans. A well-established feline model of SD allows characterization of the disease in a large animal model and provides a means to test the safety and efficacy of therapeutic interventions before initiating clinical trials. In this study, we demonstrate a robust central nervous system (CNS) inflammatory response in feline SD, primarily marked by expansion and activation of the microglial cell population. Quantification of major histocompatibility complex II (MHC-II) labeling revealed significant up-regulation throughout the CNS with areas rich in white matter most severely affected. Expression of the leukocyte chemokine macrophage inflammatory protein-1 alpha (MIP-1α) was also up-regulated in the brain. SD cats were treated with intracranial delivery of adeno-associated viral (AAV) vectors expressing feline Hex, with a study endpoint 16weeks post treatment. AAV-mediated gene delivery repressed the expansion and activation of microglia and normalized MHC-II and MIP-1α levels. These data reiterate the profound inflammatory response in SD and show that neuroinflammation is abrogated after AAV-mediated restoration of enzymatic activity.

After oxidation, zinc nanoparticles lose their ability to enhance responses to odorants.

Electrical responses of olfactory sensory neurons to odorants were examined in the presence of zinc nanoparticles of various sizes and degrees of oxidation. The zinc nanoparticles were prepared by the underwater electrical discharge method and analyzed by atomic force microscopy and X-ray photoelectron spectroscopy. Small (1.2 ± 0.3 nm) zinc nanoparticles significantly enhanced electrical responses of olfactory neurons to odorants. After oxidation, however, these small zinc nanoparticles were no longer capable of enhancing olfactory responses. Larger zinc oxide nanoparticles (15 nm and 70 nm) also did not modulate responses to odorants. Neither zinc nor zinc oxide nanoparticles produced olfactory responses when added without odorants. The enhancement of odorant responses by small zinc nanoparticles was explained by the creation of olfactory receptor dimers initiated by small zinc nanoparticles. The results of this work will clarify the mechanisms for the initial events in olfaction, as well as to provide new ways to alleviate anosmia related to the loss of olfactory receptors.

Adiponectin downregulation is associated with volume overload-induced myocyte dysfunction in rats.

AIM: Adiponectin has been reported to exert protective effects during pathological ventricular remodeling, but the role of adiponectin in volume overload-induced heart failure remains unclear. In this study we investigated the effect of adiponectin on cardiac myocyte contractile dysfunction following volume overload in rats. METHODS: Volume overload was surgically induced in rats by infrarenal aorta-vena cava fistula. The rats were intravenously administered adenoviral adiponectin at 2-, 6- and 9-weeks following fistula. The protein expression of adiponectin, adiponectin receptors (AdipoR1/R2 and T-cadherin) and AMPK activity were measured using Western blot analyses. Isolated ventricular myocytes were prepared at 12 weeks post-fistula to examine the contractile performance of myocytes and intracellular Ca(2+) transient. RESULTS: A-V fistula resulted in significant reductions in serum and myocardial adiponectin levels, myocardial adiponectin receptor (AdipoR1/R2 and T-cadherin) levels, as well as myocardial AMPK activity. Consistent with these changes, the isolated myocytes exhibited significant depression in cell shortening and intracellular Ca(2+) transient. Administration of adenoviral adiponectin significantly increased serum adiponectin levels and prevented myocyte contractile dysfunction in fistula rats. Furthermore, pretreatment of isolated myocytes with recombinant adiponectin (2.5 µg/mL) significantly improved their contractile performance in fistula rats, but had no effects in control or adenoviral adiponectin-administered rats. CONCLUSION: These results demonstrate a positive correlation between adiponectin downregulation and volume overload-induced ventricular remodeling. Adiponectin plays a protective role in volume overload-induced heart failure.

Anterior-posterior dissociation of the default mode network in dogs.

The default mode network (DMN) in humans has been extensively studied using seed-based correlation analysis (SCA) and independent component analysis (ICA). While DMN has been observed in monkeys as well, there are conflicting reports on whether they exist in rodents. Dogs are higher mammals than rodents, but cognitively not as advanced as monkeys and humans. Therefore, they are an interesting species in the evolutionary hierarchy for probing the comparative functions of the DMN across species. In this study, we sought to know whether the DMN, and consequently its functions such as self-referential processing, are exclusive to humans/monkeys or can we also observe the DMN in animals such as dogs. To address this issue, resting state functional MRI data from the brains of lightly sedated dogs and unconstrained and fully awake dogs were acquired, and ICA and SCA were performed for identifying the DMN. Since anesthesia can alter resting state networks, confirming our results in awake dogs was essential. Awake dog imaging was accomplished by training the dogs to keep their head still using reinforcement behavioral adaptation techniques. We found that the anterior (such as anterior cingulate and medial frontal) and posterior regions (such as posterior cingulate) of the DMN were dissociated in both awake and anesthetized dogs.

Testicular development in male rats is sensitive to a soy-based diet in the neonatal period.

Approximately 30% of infants in the United States are exposed to high doses of isoflavones resulting from soy infant formula consumption. Soybeans contain the isoflavones genistin and daidzin, which are hydrolyzed in the gastrointestinal tract to their genistein and daidzein aglycones. Both aglycones possess hormonal activity and may interfere with male reproductive development. Testosterone, which supports male fertility, is mainly produced by testicular Leydig cells. Our previous studies indicated that perinatal exposure of male rats to isoflavones induced proliferative activity in Leydig cells and increased testosterone concentrations into adulthood. However, the relevance of the neonatal period as part of the perinatal window of isoflavone exposure remains to be established. The present study examined the effects of exposure to isoflavones on male offspring of dams maintained on a casein-based control or whole soybean diet in the neonatal period, that is, Days 2 to 21 postpartum. The results showed that the soybean diet stimulated proliferative activity in developing Leydig cells while suppressing their steroidogenic capacity in adulthood. In addition, isoflavone exposure decreased production of anti-Müllerian hormone by Sertoli cells. Similar to our previous in vitro studies of genistein action in Leydig cells, daidzein induced proliferation and interfered with signaling pathways to suppress steroidogenic activity. Overall, the data showed that the neonatal period is a sensitive window of exposure to isoflavones and support the view that both genistein and daidzein are responsible for biological effects associated with soy-based diets.

The vomeronasal complex of nocturnal strepsirhines and implications for the ancestral condition in primates.

This study investigates the vomeronasal organ in extant nocturnal strepsirhines as a model for ancestral primates. Cadaveric samples from 10 strepsirhine species, ranging from fetal to adult ages, were studied histologically. Dimensions of structures in the vomeronasal complex, such as the vomeronasal neuroepithelium (VNNE) and vomeronasal cartilage (VNC) were measured in serial sections and selected specimens were studied immunohistochemically to determine physiological aspects of the vomeronasal sensory neurons (VSNs). Osteological features corresponding to vomeronasal structures were studied histologically and related to 3-D CT reconstructions. The VNC consistently rests in a depression on the palatal portion of the maxilla, which we refer to as the vomeronasal groove (VNG). Most age comparisons indicate that in adults VNNE is about twice the length compared with perinatal animals. In VNNE volume, adults are 2- to 3-fold larger compared with perinatal specimens. Across ages, a strong linear relationship exists between VNNE dimensions and body length, mass, and midfacial length. Results indicate that the VNNE of nocturnal strepsirhines is neurogenic postnatally based on GAP43 expression. In addition, based on Olfactory Marker Protein expression, terminally differentiated VSNs are present in the VNNE. Therefore, nocturnal strepsirhines have basic similarities to rodents in growth and maturational characteristics of VSNs. These results indicate that a functional vomeronasal system is likely present in all nocturnal strepsirhines. Finally, given that osteological features such as the VNG are visible on midfacial bones, primate fossils can be assessed to determine whether primate ancestors possessed a vomeronasal complex morphologically similar to that of modern nocturnal strepsirhines.

Olfactory responses to explosives associated odorants are enhanced by zinc nanoparticles.

Many odorants related to manufactured explosives have low volatilities and are barely detectable as odors. We previously reported that zinc metal nanoparticles increased rat olfactory epithelium responses, measured by electroolfactogram (EOG), to several odorants. Here, we report that nanomolar concentrations of zinc metal nanoparticles strongly enhanced olfactory responses to the explosives related odorants cyclohexanone, methyl benzoate, acetophenone, and eugenol. Rat olfactory epithelium was exposed to metal nanoparticles and odorant responses were quantified by EOG. Zinc nanoparticles added to explosive odorants strongly increased the odorant response in a dose-dependent manner. The enzymatic breakdown of the second messenger cyclic adenosine monophosphate (cAMP) was prevented by adding the membrane-permeable phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). This caused the olfactory cilia cAMP concentration to increase and generated EOG signals. The EOG responses generated by IBMX were not enhanced by zinc nanoparticles. Based on these observations, we conclude that zinc nanoparticles act at the receptor site and are involved in the initial events of olfaction. Our results suggest that zinc metal nanoparticles can be used to facilitate a canine detection of explosive odorants.

The vomeronasal organ of New World monkeys (platyrrhini).

Although all platyrrhine primates possess a vomeronasal organ (VNO), few species have been studied in detail. Here, we revisit the microanatomy of the VNO and related features in serially sectioned samples from 41 platyrrhine cadavers (14 species) of mixed age. Procedures to identify terminally differentiated vomeronasal sensory neurons (VSNs) via immunolabeling of olfactory marker protein (OMP) were used on selected specimens. The VNO varies from an elongated epithelial tube (e.g., Ateles fusciceps) to a dorsoventrally expanded sac (e.g., Saguinus spp.). The cartilage that surrounds the VNO is J-shaped or U-shaped in most species, and articulates with a groove on the bony palate. Preliminary results indicate a significant correlation between the length of this groove and length of the VNO neuroepithelium, indicating this feature may serve as a skeletal correlate. The VNO neuroepithelium could be identified in all adult primates except Alouatta, in which poor preservation prevented determination. The VNO of Ateles, described in detail for the first time, had several rows of VSNs and nerves in the surrounding lamina propria. Patterns of OMP-reactivity in the VNO of perinatal platyrrhines indicate that few or no terminally differentiated VSNs are present at birth, thus supporting the hypothesis that some platyrrhines may have delayed maturation of the VNO. From a functional perspective, all platyrrhines studied possess structures required for chemoreception (VSNs, vomeronasal nerves). However, some microanatomical findings, such as limited reactivity to OMP in some species, indicate that some lineages of New World monkeys may have a reduced or vestigial vomeronasal system.

Olfactory marker protein expression in the vomeronasal neuroepithelium of tamarins (Saguinus spp).

Knowledge of the vomeronasal neuroepithelium (VNNE) microanatomy is disproportionately based on rodents. To broaden our knowledge, we examined olfactory marker protein (OMP) expression in a sample of twenty-three non-human primates. The density of OMP (+) vomeronasal sensory neurons (VSNs) in the VNNE was measured. Here we compared OMP (+) VSN density in five species of Saguinus (a genus of New World monkey) of different ages to a comparative primate sample that included representatives of every superfamily in which a VNO is postnatally present. In Saguinus spp., the VNNE at birth is thin, usually comprising one or two nuclear rows. At all ages studied, few VNNE cells are OMP reactive as view in coronal sections. In the comparative sample, the OMP (+) VSNs appear to be far more numerous in the spider monkey (another New World monkey) and the bushbaby (a distant relative). Other species (e.g., owl monkey) had a similar low density of OMP (+) VSNs as in Saguinus. These results expand our earlier finding that few VSNs are OMP (+) in Saguinus geoffroyi to other species of the genus. Our sample indicates that the number of OMP (+) VSNs in primates varies from ubiquitous to few with New World monkeys varying the most. The scarcity of OMP (+) cells in some primate VNOs reflects a lower number of terminally differentiated VSNs compared to a diverse range of mammals. If primates with relatively few OMP (+) VSNs have a functional vomeronasal system, OMP is not critical for stimulus detection.

Odorant response kinetics from cultured mouse olfactory epithelium at different ages in vitro.

Mammalian olfactory epithelium can withstand the external environment, undergo life-long regeneration, and respond to thousands of odorant stimuli, making it an attractive system for a variety of studies. Previously, we described a long-lived olfactory coculture of olfactory epithelium and bulb tissues and we present here the kinetic properties of that culture system. Neonatal mouse epithelial-bulbar explants were grown for periods as long as 121 days in vitro (DIV), nearly doubling the survival time of our previously longest lived cultures. Cultures at all ages responded to air-borne odorants. The youngest cultures (1-15 DIV) showed shorter half-rise and half-decay times than older cultures (21-121 DIV), and were more variable in their half-decay times. Zinc nanoparticles enhanced electro-olfactogram responses of both younger and older cultures and both groups were immunopositive for olfactory marker protein. The results show that our olfactory culture model can support mature, odorant-responsive olfactory receptor neurons that possess many of the response features of in situ olfactory receptor neurons.

Developmental exposures of male rats to soy isoflavones impact Leydig cell differentiation.

Testicular Leydig cells, which are the predominant source of the male sex steroid hormone testosterone, express estrogen receptors (ESRs) and are subject to regulation by estrogen. Following ingestion, the two major isoflavones in soybeans, genistin and daidzin, are hydrolyzed by gut microflora to form genistein and daidzein, which have the capacity to bind ESRs and affect gene expression. Thus, the increasing use of soy-based products as nondairy sources of protein has raised concerns about the potential of these products to cause reproductive toxicity. In the present study, perinatal exposure of male rats to isoflavones induced proliferative activity in Leydig cells. Isoflavones have the capacity to act directly as mitogens in Leydig cells, because genistein treatment induced Leydig cell division in vitro. Genistein action regulating Leydig cell division involved ESRs, acting in concert with signaling molecules in the transduction pathway mediated by protein kinase B (AKT) and mitogen-activated protein kinase (MAPK). Enhanced proliferative activity in the prepubertal period increased Leydig cell numbers, which alleviated deficits in androgen biosynthesis and/or augmented serum and testicular testosterone concentrations in adulthood. Together, these observations indicate that the perinatal exposures of male rats to isoflavones affected Leydig cell differentiation, and they imply that including soy products in the diets of neonates has potential implications for testis function.

Enhancement of odorant-induced responses in olfactory receptor neurons by zinc nanoparticles.

Zinc metal nanoparticles in picomolar concentrations strongly enhance odorant responses of olfactory sensory neurons. One- to 2-nm metallic particles contain 40-300 zinc metal atoms, which are not in an ionic state. We exposed rat olfactory epithelium to metal nanoparticles and measured odorant responses by electroolfactogram and whole-cell patch clamp. A small amount of zinc nanoparticles added to an odorant or an extracellular/intracellular particle perfusion strongly increases the odorant response in a dose-dependent manner. Zinc nanoparticles alone produce no odor effects. Copper, gold, or silver nanoparticles do not produce effects similar to those of zinc. If zinc nanoparticles are replaced by Zn(+2) ions in the same concentration range, we observed a reduction of the olfactory receptor neuron odorant response. Based on these observations, we hypothesize that zinc nanoparticles are closely located to the interface between the guanine nucleotide-binding protein and the receptor proteins and are involved in transferring signals in the initial events of olfaction. Our results suggest that zinc metal nanoparticles can be used to enhance and sustain the initial olfactory events.

Genistein decreases androgen biosynthesis in rat Leydig cells by interference with luteinizing hormone-dependent signaling.

Testicular Leydig cells express estrogen receptors and are the predominant source of the male sex steroid hormone testosterone (T). Previous studies demonstrated that genistein acts through estrogen receptors in Leydig cells. In the present study, pre-treatment of Leydig cells isolated from 35 day-old male Long Evans rats with the epidermal growth factor receptor (EGFR) kinase inhibitor AG 1478 abrogated genistein inhibition of T biosynthesis. Also, incubation of Leydig cells in culture medium containing epidermal growth factor (EGF) decreased T secretion (control: 255+/-16; EGF: 190+/-17ng/10(6) cells, 24h) (P<0.05). However, T secretion by genistein-treated Leydig cells (0.1nM, 10muM; 24h) was rescued by post-treatment incubation with forskolin (control: 275+/-28 versus 325+/-35; 780+/-85; ng/10(6) cells, 3h) and dibutyryl cyclic adenosine 3'-5'-monophosphate (dbcAMP) (control: 370+/-65 versus 580+/-75; 2500+/-200; ng/10(6) cells, 3h) (P>0.05). Furthermore, post-treatment incubation with cholera toxin, an activator of G proteins, caused genistein-treated Leydig cells to produce similar T amounts as untreated control (control: 55+/-5 versus 52+/-2 and 47+/-4; ng/10(6) cells, 3h) (P>0.05). These observations imply that genistein action interferes with coupling of transmembrane luteinizing hormone receptors (LHR) with G proteins. Uncoupling of LHR from G proteins adversely affects adenylate cyclase function and impacts LH-dependent stimulation of Leydig cells. These findings have implications for testicular steroidogenesis in individuals exposed to genistein and soy-based products.

Comparative analysis of Xenopus tropicalis hepcidin I and hepcidin II genes.

Hepcidin is an antimicrobial peptide and an iron-regulatory hormone that is conserved in fish, amphibians, and mammalians. Here we report the genomic and biochemical characterization of two amphibian hepcidins (tHEP1 and tHEP2) from the Western clawed frog (Xenopus tropicalis). Similar to fish and mammalian hepcidins, both tHEP1 and tHEP2 genes contain three exons and two introns. The predicted mature tHEP1 and tHEP2 hepcidins are a 25 amino acid peptide and a 24 amino acid peptide, respectively. Both tHEP1 and tHEP2 are strongly expressed in the liver and kidney, with detectable expression in the heart. In addition, tHEP2 is also moderately expressed in the stomach and testis. The expression of tHEP2 (but not tHEP1) in the liver is strongly induced by iron overloading, while the expression of tHEP1 (but not tHEP2) in the liver is significantly inhibited by corticosterone. Genomic analysis of the promoter regions of these two frog hepcidin genes indicates that transcription regulation factors NF-kappaB and C/EBPbeta may be involved in hepcidin regulation by iron. Hence, X. tropicalis is a useful model for the study of molecular evolution, transcriptional regulation, and structure-activity relationships of vertebrate hepcidins.

Activation of Penile Proadipogenic Peroxisome Proliferator-Activated Receptor gamma with an Estrogen: Interaction with Estrogen Receptor Alpha during Postnatal Development.

Exposure to the estrogen receptor alpha (ERalpha) ligand diethylstilbesterol (DES) between neonatal days 2 to 12 induces penile adipogenesis and adult infertility in rats. The objective of this study was to investigate the in vivo interaction between DES-activated ERalpha and the proadipogenic transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma). Transcripts for PPARs alpha, beta, and gamma and gamma1a splice variant were detected in Sprague-Dawley normal rat penis with PPARgamma predominating. In addition, PPARgamma1b and PPARgamma2 were newly induced by DES. The PPARgamma transcripts were significantly upregulated with DES and reduced by antiestrogen ICI 182, 780. At the cellular level, PPARgamma protein was detected in urethral transitional epithelium and stromal, endothelial, neuronal, and smooth muscular cells. Treatment with DES activated ERalpha and induced adipocyte differentiation in corpus cavernosum penis. Those adipocytes exhibited strong nuclear PPARgamma expression. These results suggest a biological overlap between PPARgamma and ERalpha and highlight a mechanism for endocrine disruption.

Reconstruction and morphometric analysis of the nasal airway of the dog (Canis familiaris) and implications regarding olfactory airflow.

The canine nasal airway is an impressively complex anatomical structure, having many functional roles. The complicated branching and intricate scrollwork of the nasal conchae provide large surface area for heat, moisture, and odorant transfer. Of the previous anatomical studies of the canine nasal airway, none have included a detailed rendering of the maxilloturbinate and ethmoidal regions of the nose. Here, we present a high-resolution view of the nasal airway of a large dog, using magnetic resonance imaging scans. Representative airway sections are shown, and a three-dimensional surface model of the airway is reconstructed from the image data. The resulting anatomic structure and detailed morphometric data of the airway provide insight into the functional nature of canine olfaction. A complex airway network is revealed, wherein the branched maxilloturbinate and ethmoturbinate scrolls appear structurally distinct. This is quantitatively confirmed by considering the fractal dimension of each airway, which shows that the maxilloturbinate airways are more highly contorted than the ethmoidal airways. Furthermore, surface areas of the maxilloturbinate and ethmoidal airways are shown to be much different, despite having analogous physiological functions. Functionally, the dorsal meatus of the canine nasal airway is shown to be a bypass for odorant-bearing inspired air around the complicated maxilloturbinate during sniffing for olfaction. Finally, nondimensional analysis is used to show that the airflow within both the maxilloturbinate and ethmoturbinate regions must be laminar. This work has direct relevance to biomimetic sniffer design, chemical trace detector development, intranasal drug delivery, and inhalation toxicology.