A Trans-Governmental Collaboration to Independently Evaluate SARS-CoV-2 Serology Assays.

The emergence of SARS-CoV-2 created a crucial need for serology assays to detect anti-SARS-CoV-2 antibodies, which led to many serology assays entering the market. A trans-government collaboration was created in April 2020 to independently evaluate the performance of commercial SARS-CoV-2 serology assays and help inform U.S. Food and Drug Administration (FDA) regulatory decisions. To assess assay performance, three evaluation panels with similar antibody titer distributions were assembled. Each panel consisted of 110 samples with positive (n = 30) serum samples with a wide range of anti-SARS-CoV-2 antibody titers and negative (n = 80) plasma and/or serum samples that were collected before the start of the COVID-19 pandemic. Each sample was characterized for anti-SARS-CoV-2 antibodies against the spike protein using enzyme-linked immunosorbent assays (ELISA). Samples were selected for the panel when there was agreement on seropositivity by laboratories at National Cancer Institute's Frederick National Laboratory for Cancer Research (NCI-FNLCR) and Centers for Disease Control and Prevention (CDC). The sensitivity and specificity of each assay were assessed to determine Emergency Use Authorization (EUA) suitability. As of January 8, 2021, results from 91 evaluations were made publicly available (https://open.fda.gov/apis/device/covid19serology/, and https://www.cdc.gov/coronavirus/2019-ncov/covid-data/serology-surveillance/serology-test-evaluation.html). Sensitivity ranged from 27% to 100% for IgG (n = 81), from 10% to 100% for IgM (n = 74), and from 73% to 100% for total or pan-immunoglobulins (n = 5). The combined specificity ranged from 58% to 100% (n = 91). Approximately one-third (n = 27) of the assays evaluated are now authorized by FDA for emergency use. This collaboration established a framework for assay performance evaluation that could be used for future outbreaks and could serve as a model for other technologies. IMPORTANCE The SARS-CoV-2 pandemic created a crucial need for accurate serology assays to evaluate seroprevalence and antiviral immune responses. The initial flood of serology assays entering the market with inadequate performance emphasized the need for independent evaluation of commercial SARS-CoV-2 antibody assays using performance evaluation panels to determine suitability for use under EUA. Through a government-wide collaborative network, 91 commercial SARS-CoV-2 serology assay evaluations were performed. Three evaluation panels with similar overall antibody titer distributions were assembled to evaluate performance. Nearly one-third of the assays evaluated met acceptable performance recommendations, and two assays had EUAs revoked and were removed from the U.S. market based on inadequate performance. Data for all serology assays evaluated are available at the FDA and CDC websites (https://open.fda.gov/apis/device/covid19serology/, and https://www.cdc.gov/coronavirus/2019-ncov/covid-data/serology-surveillance/serology-test-evaluation.html).

TIPICO XI: report of the first series and podcast on infectious diseases and vaccines (aTIPICO).

TIPiCO is an annual expert meeting and workshop on infectious diseases and vaccination. The edition of 2020 changed its name and format to aTIPiCO, the first series and podcasts on infectious diseases and vaccines. A total of 13 prestigious experts from different countries participated in this edition launched on the 26 November 2020. The state of the art of coronavirus disease-2019 (COVID-19) and the responsible pathogen, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and the options to tackle the pandemic situation were discussed in light of the knowledge in November 2020. Despite COVID-19, the status of other infectious diseases, including influenza infections, respiratory syncytial virus disease, human papillomavirus infection, measles, pertussis, tuberculosis, meningococcal disease, and pneumococcal disease, were also addressed. The essential lessons that can be learned from these diseases and their vaccines to use in the COVID-19 pandemic were also commented with the experts.

Effect of Ovarian Hormones and Mating Experience on the Preference of Female Mice to Investigate Male Urinary Pheromones.

In female mice, the expression of receptive lordosis behavior requires estradiol and progesterone actions in the nervous system; however, the contribution of these hormones to females' motivation to seek out male pheromones is less clear. In an initial experiment, sexually naïve ovary-intact female mice preferred to investigate (make nasal contact with) testes-intact male as opposed to estrous female urine, provided they were in vaginal estrus. In a second experiment, groups of sexually naïve and mating-experienced, ovariectomized females were tested for urinary pheromone preference first without and then with ovarian hormone replacement. Without hormone replacement, sexually naïve ovariectomized females showed no preference for male over female urinary pheromones whereas mating-experienced females preferred to investigate male pheromones. Ovariectomized females in both groups preferred male over female urine after sequential s.c. injections with estradiol benzoate followed 2 days later with progesterone and after prolonged (7 days) exposure to estradiol alone. Our results indicate that in sexually naïve female mice estradiol, perhaps aided by progesterone, is required to motivate a preference to seek out male pheromones whereas after mating experience females' preference to investigate male pheromones persists even in the absence of ovarian hormone action.

Novel near-diploid ovarian cancer cell line derived from a highly aneuploid metastatic ovarian tumor.

A new ovarian near-diploid cell line, OVDM1, was derived from a highly aneuploid serous ovarian metastatic adenocarcinoma. A metastatic tumor was obtained from a 47-year-old Ashkenazi Jewish patient three years after the first surgery removed the primary tumor, both ovaries, and the remaining reproductive organs. OVDM1 was characterized by cell morphology, genotyping, tumorigenic assay, mycoplasma testing, spectral karyotyping (SKY), and molecular profiling of the whole genome by aCGH and gene expression microarray. Targeted sequencing of a panel of cancer-related genes was also performed. Hierarchical clustering of gene expression data clearly confirmed the ovarian origin of the cell line. OVDM1 has a near-diploid karyotype with a low-level aneuploidy, but samples of the original metastatic tumor were grossly aneuploid. A number of single nucleotide variations (SNVs)/mutations were detected in OVDM1 and the metastatic tumor samples. Some of them were cancer-related according to COSMIC and HGMD databases (no founder mutations in BRCA1 and BRCA2 have been found). A large number of focal copy number alterations (FCNAs) were detected, including homozygous deletions (HDs) targeting WWOX and GATA4. Progression of OVDM1 from early to late passages was accompanied by preservation of the near-diploid status, acquisition of only few additional large chromosomal rearrangements and more than 100 new small FCNAs. Most of newly acquired FCNAs seem to be related to localized but massive DNA fragmentation (chromothripsis-like rearrangements). Newly developed near-diploid OVDM1 cell line offers an opportunity to evaluate tumorigenesis pathways/events in a minor clone of metastatic ovarian adenocarcinoma as well as mechanisms of chromothripsis.

DREADD-induced silencing of the medial amygdala reduces the preference for male pheromones and the expression of lordosis in estrous female mice.

Sexually naïve estrous female mice seek out male urinary pheromones; however, they initially display little receptive (lordosis) behavior in response to male mounts. Vomeronasal-accessory olfactory bulb inputs to the medial amygdala (Me) regulate courtship in female rodents. We used a reversible inhibitory chemogenetic technique (Designer Receptors Exclusively Activated by Designer Drugs; DREADDs) to assess the contribution of Me signaling to females' preference for male pheromones and improvement in receptivity normally seen with repeated testing. Sexually naïve females received bilateral Me injections of an adeno-associated virus carrying an inhibitory DREADD. Females were later ovariectomized, treated with ovarian hormones, and given behavioral tests following intraperitoneal injections of saline or clozapine-N-oxide (CNO; which hyperpolarizes infected Me neurons). CNO attenuated females' preference to investigate male vs. female urinary odors. Repeated CNO treatment also slowed the increase in lordosis otherwise seen in females given saline. However, when saline was given to females previously treated with CNO, their lordosis quotients were as high as other females repeatedly given saline. No disruptive behavioral effects of CNO were seen in estrous females lacking DREADD infections of the Me. Finally, CNO attenuated the ability of male pheromones to stimulate Fos expression in the Me of DREADD-infected mice but not in non-infected females. Our results affirm the importance of Me signaling in females' chemosensory preferences and in the acute expression of lordosis. However, they provide no indication that Me signaling is required for the increase in receptivity normally seen after repeated hormone priming and testing with a male.

A comparison of the effects of male pheromone priming and optogenetic inhibition of accessory olfactory bulb forebrain inputs on the sexual behavior of estrous female mice.

Previous research has shown that repeated testing with a stimulus male is required for ovariectomized, hormone-primed female mice to become sexually receptive (show maximal lordosis quotients; LQs) and that drug-induced, epigenetic enhancement of estradiol receptor function accelerated the improvement in LQs otherwise shown by estrous females with repeated testing. We asked whether pre-exposure to male pheromones ('pheromone priming') would also accelerate the improvement in LQs with repeated tests and whether optogenetic inhibition of accessory olfactory bulb (AOB) projection neurons could inhibit lordosis in sexually experienced estrous female mice. In Experiment 1, repeated priming with soiled male bedding failed to accelerate the progressive improvement in LQs shown by estrous female mice across 5 tests, although the duration of each lordosis response and females' investigation of male body parts during the first test was augmented by such priming. In Experiment 2, acute optogenetic inhibition of AOB inputs to the forebrain during freely moving behavioral tests significantly reduced LQs, suggesting that continued AOB signaling to the forebrain during mating is required for maximal lordotic responsiveness even in sexually experienced females. Our results also suggest that pheromonal stimulation, by itself, cannot substitute for the full complement of sensory stimulation received by estrous females from mounting males that normally leads to the progressive improvement in their LQs with repeated testing.

Evaluation of a variable-thread tapered implant in extraction sites with immediate temporization: a 3-year multicenter clinical study.

BACKGROUND: The purpose of this clinical study is to evaluate the radiographic bone remodeling, survival rate, and soft tissue health surrounding a variable-thread tapered implant immediately placed in extraction sites. METHODS: Sixty implants were placed in 55 patients at six centers according to a predetermined protocol. All implants were placed in extraction sockets and were subjected to immediate temporization and function. Definitive prostheses (58 single crowns and one two-unit fixed bridge) were placed within the first year. Clinical and radiographic examinations were performed at implant placement and after 3, 6, 12, 24, and 36 months. Measurements of implant stability, papilla index, plaque, peri-implant mucosa, and marginal bone levels were recorded at each visit. RESULTS: Thirty-five implants were evaluated at both implant insertion and 3-year follow-up. Bone levels were observed at 6 months after surgery and yearly intervals thereafter and remained stable throughout the study. There was a slight decrease in mean bone level from -0.68 mm at implant insertion to -0.93 mm at the 6-month recall and then an increase of bone to -0.53 mm from the reference point at the 2-year follow-up (an average increase of 0.15 mm from implant insertion). Bone levels remained steady between the 2-year recall and the 3-year recall. Papilla scores increased significantly (P <0.001; Wilcoxon signed-rank test) from insertion to the 3-year follow-up, with most of the increase occurring during the first year. Patient assessments of function, esthetics, feel of implant, speech, and self-esteem also showed significant improvement over the course of the study. CONCLUSIONS: The results, over 36 months, indicate that the variable-thread tapered implant can be used safely and effectively under demanding conditions as an immediate postextraction tooth replacement. Bone remodeling remained stable with a slight increase, and patients expressed high levels of satisfaction with the restorative results over the course of the study.

Disruption of urinary odor preference and lordosis behavior in female mice given lesions of the medial amygdala.

Previous research showed that axonal inputs to both anterior and posterior subdivisions of the medial amygdala from the main and accessory olfactory bulbs of female mice, respectively, process volatile and non-volatile pheromonal signals from male conspecifics. In the present study we found that bilateral electrolytic lesions that included posterior portions, but not the anterior subdivision alone of the medial amygdala (Me) blocked the preference of estrous female mice to investigate volatile urinary odors from testes-intact vs. castrated males. Similar results were obtained in separate tests in which nasal contact with urinary stimuli was permitted. In addition, total time investigating volatile urinary stimuli was reduced in subjects with posterior Me lesions. Subjects were able to discriminate volatile urinary odors from testes-intact vs. castrated male mice, suggesting that this disruption of odor preference did not result from the inability of females given amygdaloid lesions to discriminate these male urinary odors. Bilateral lesions of the Me that were either restricted to the anterior or posterior subdivisions, or included areas of both regions, caused significant reductions in the display of lordosis behavior in estrous female mice. Our results suggest that the Me is a critical segment of the olfactory circuit that controls both mate recognition and mating behavior in the female mouse.

The role of upregulated miRNAs and the identification of novel mRNA targets in prostatospheres.

TICs are characterized by their ability to self-renew, differentiate and initiate tumor formation. miRNAs are small noncoding RNAs that bind to mRNAs resulting in regulation of gene expression and biological functions. The role of miRNAs and TICs in cancer progression led us to hypothesize that miRNAs may regulate genes involved in TIC maintenance. Using whole genome miRNA and mRNA expression profiling of TICs from primary prostate cancer cells, we identified a set of up-regulated miRNAs and a set of genes down-regulated in PSs. Inhibition of these miRNAs results in a decrease of prostatosphere formation and an increase in target gene expression. This study uses genome-wide miRNA profiling to analyze expression in TICs. We connect aberrant miRNA expression and deregulated gene expression in TICs. These findings can contribute to a better understanding of the molecular mechanisms governing TIC development/maintenance and the role that miRNAs have in the fundamental biology of TICs.

Consenso para el diagnóstico clínico y microbiológico y la prevención de la infección por Bordetella pertussis / Consensus on the clinical and microbiologic diagnosis of Bordetella pertussis, and infection prevention

La tos ferina sigue siendo responsable de una carga de enfermedad importante en el mundo. Aunque la implementación del uso de la vacuna contra esta enfermedad ha disminuido en gran medida el número de casos en la población pediátrica, se ha observado que la inmunidad inducida por la vacuna y por la infeccion natural disminuye con el tiempo lo que hace nuevamente susceptibles a adolescentes y adultos jóvenes que pueden transmitir la enfermedad a lactantes no inmunizados o con esquema de vacunación incompleto. Este documento, resultado de la reunión de un grupo internacional de expertos en la Ciudad de México, ha analizado la información médica reciente para establecer el estado actual de la epidemiología, diagnóstico, vigilancia y, especialmente, el valor de la dosis de refuerzo con dTpa en adolescentes y adultos como estrategia de prevención de tos ferina en México.

Pertussis continues to be responsible for a significant disease burden worldwide. Although immunization practices have reduced the occurrence of the disease among children, waning vaccine- and infection-induced immunity still allows the disease to affect adolescents and adults who, in turn, can transmit the disease to non-immunized or partially immunized infants. This document is the result of a meeting in Mexico City of international experts who analyzed recent medical information in order to establish the current status of the epidemiology, diagnosis and surveillance of pertussis and, especially, the value of the dTpa booster dose in adolescents and adults as a pertussis prevention strategy in Mexico.

The type IV phosphodiesterase inhibitor rolipram disturbs expression and extinction of conditioned fear in mice.

Recent studies suggest that intracellular signaling pathways involving cyclic adenosine monophosphate (cAMP) may be related to fear processing and long-term memory formation. The type IV phosphodiesterase (PDE4) inhibitor rolipram prevents breakdown of cAMP, enhances long-term memory and may reduce anxiety. In the present study we investigated the role of rolipram in the expression (0, 0.2, or 1 mg/kg), acquisition (0, 0.03, 0.2 or 1 mg/kg), and extinction (0, 0.03, 0.2, 1 mg/kg) of fear using a fear-potentiated startle paradigm in mice. It was shown that rolipram reduced the expression (Experiment 1), did not influence acquisition (Experiment 2) and disturbed between-session extinction (Experiments 3 and 4) of fear responses to conditioned tones. Because within-session extinction was not impaired by rolipram and because low (i.e. 0.03 and 0.2 mg/kg) doses strongly affected extinction but not expression of fear, these findings suggest that the effect of rolipram on extinction is not directly dependent on its effect on fear expression. Taken together, these experiments indicate that preventing breakdown of cAMP interferes with the expression and extinction consolidation of conditioned fear.

Tumor and reproductive traits are linked by RNA metabolism genes in the mouse ovary: a transcriptome-phenotype association analysis.

BACKGROUND: The link between reproductive life history and incidence of ovarian tumors is well known. Periods of reduced ovulations may confer protection against ovarian cancer. Using phenotypic data available for mouse, a possible association between the ovarian transcriptome, reproductive records and spontaneous ovarian tumor rates was investigated in four mouse inbred strains. NIA15k-DNA microarrays were employed to obtain expression profiles of BalbC, C57BL6, FVB and SWR adult ovaries. RESULTS: Linear regression analysis with multiple-test control (adjusted p ≤ 0.05) resulted in ovarian tumor frequency (OTF) and number of litters (NL) as the top-correlated among five tested phenotypes. Moreover, nearly one-hundred genes were coincident between these two traits and were decomposed in 76 OTF(-) NL(+) and 20 OTF(+) NL(-) genes, where the plus/minus signs indicate the direction of correlation. Enriched functional categories were RNA-binding/mRNA-processing and protein folding in the OTF(-) NL(+) and the OTF(+) NL(-) subsets, respectively. In contrast, no associations were detected between OTF and litter size (LS), the latter a measure of ovulation events in a single estrous cycle. CONCLUSION: Literature text-mining pointed to post-transcriptional control of ovarian processes including oocyte maturation, folliculogenesis and angiogenesis as possible causal relationships of observed tumor and reproductive phenotypes. We speculate that repetitive cycling instead of repetitive ovulations represent the actual link between ovarian tumorigenesis and reproductive records.

Visualization and identification of IL-7 producing cells in reporter mice.

Interleukin-7 (IL-7) is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC) transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein) accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging.

Aryl hydrocarbon receptor expression is associated with a family history of upper gastrointestinal tract cancer in a high-risk population exposed to aromatic hydrocarbons.

BACKGROUND: Polycyclic aromatic hydrocarbon (PAH) exposure is a risk factor for esophageal squamous cell carcinoma, and PAHs are ligands of the aryl hydrocarbon receptor (AhR). This study measured the expression of AhR and related genes in frozen esophageal cell samples from patients exposed to different levels of indoor air pollution, who did or did not have high-grade squamous dysplasia and who did or did not have a family history of upper gastrointestinal tract (UGI) cancer. METHODS: 147 samples were evaluated, including 23 (16%) from patients with high-grade dysplasia and 48 (33%) from patients without dysplasia who heated their homes with coal, without a chimney (a "high" indoor air pollution group), and 27 (18%) from patients with high-grade dysplasia and 49 (33%) from patients without dysplasia who did not heat their homes at all (a "low" indoor air pollution group). Sixty-four (44%) had a family history of UGI cancer. RNA was extracted and quantitative PCR analysis was done. RESULTS: AhR gene expression was detectable in 85 (58%) of the samples and was >9-fold higher in those with a family history of UGI cancer [median expression (interquartile range), -1,964 (-18,000, -610) versus -18,000 (-18,000, -1036); P = 0.02, Wilcoxon rank-sum test]. Heating status, dysplasia category, age, gender, and smoking were not associated with AhR expression (linear regression; all P values >or= 0.1). CONCLUSION: AhR expression was higher in patients with a family history of UGI cancer. Such individuals may be more susceptible to the deleterious effects of PAH exposure, including PAH-induced cancer.

The involvement of type IV phosphodiesterases in cocaine-induced sensitization and subsequent pERK expression in the mouse nucleus accumbens.

RATIONALE: Cocaine exposure produces sensitization that is partly mediated by cyclic adenosine monophosphate (cAMP) pathways within the nucleus accumbens (NAc). Type IV phosphodiesterases (PDE4s) break down cAMP and are required for cocaine-induced conditioned place preference. Whether PDE4 disruption attenuates induction of behavioral sensitization to cocaine and subsequent NAc expression of phosphorylated extracellular signal-regulated kinase (ERK), which is involved in cocaine-induced sensitization, is unknown. OBJECTIVES: The objective of this study was to determine whether inhibition of PDE4s prevents cocaine-induced locomotor sensitization and if reduced behavioral sensitization is accompanied by decreased expression of phosphorylated ERK (pERK) within the NAc. METHODS: Mice were administered the PDE4 inhibitor, rolipram, or vehicle before or after five daily injections of cocaine or saline, and activity was monitored on days 1 and 5. After nine drug-free days, locomotor sensitization was tested. Some subjects were sacrificed following testing for behavioral sensitization to measure pERK expression in the NAc. RESULTS: PDE4 inhibition, during the induction of sensitization, reduced behavioral sensitization only if rolipram (1.0 mg/kg) was administered before cocaine. Re-exposure to the cocaine-paired environment following a 9-day drug-free period enhanced pERK expression in the NAc core and shell. Rolipram did not alter pERK induction despite blocking behavioral sensitization. CONCLUSIONS: Rolipram given during, but not following, cocaine treatment prevents development of locomotor sensitization to cocaine but does not affect subsequent pERK activation induced by exposure to a cocaine-paired context or following a cocaine challenge. Although PDE4 inhibition during the induction of sensitization blocks the locomotor component of sensitization, other long-term changes induced by repeated cocaine treatment remain.

Gene expression and chromosomal location for susceptibility to Sjögren's syndrome.

Primary Sjögren's syndrome (SS) is a chronic inflammatory autoimmune disease affecting mainly the exocrine glands. Its physio-pathology is poorly understood and most of the knowledge has been related to the inflammatory component. The aim of this work was to evaluate gene expression profiling in fractions enriched in epithelial cells from labial salivary glands (LSGs) of patients with primary SS and identify chromosomal regions harboring susceptibility genes expressed in epithelial cells. A combined approach of gene expression and genome-wide association study was used. Enriched epithelial cell fractions were obtained from LSGs of patients and controls. Amplified total RNA was labeled and hybridized to 10K cDNA microarrays. Results were normalized and subjected to statistical and functional analysis. A genome-wide microsatellite screen at 10 cM resolution (393 markers) was performed. In salivary gland-epithelial cells from patients 528 genes were expressed differentially in comparison to controls. Pathways not previously linked to disease were found to be altered. Twenty-eight and 15 genes associated with apoptosis were up-regulated and down regulated, respectively. Interferon-related genes, most of which participated in interferon signaling, were also found to be up-regulated. From the genome-wide screen, 6 markers showed evidence of highly significant association with the disease. Of these, five loci harbor genes differentially expressed in patients LSG-epithelial cells. Our results show that in enriched gland-epithelial cells of pSS, both pro-apoptotic/anti-apoptotic and interferon signaling inhibition/stimulation balances may occur. Genes found over-expressed in epithelial cells are candidates for disease susceptibility.

Accelerated preclinical testing using transplanted tumors from genetically engineered mouse breast cancer models.

PURPOSE: The use of genetically engineered mouse (GEM) models for preclinical testing of anticancer therapies is hampered by variable tumor latency, incomplete penetrance, and complicated breeding schemes. Here, we describe and validate a transplantation strategy that circumvents some of these difficulties. EXPERIMENTAL DESIGN: Tumor fragments from tumor-bearing MMTV-PyMT or cell suspensions from MMTV-PyMT, -Her2/neu, -wnt1, -wnt1/p53(+/-), BRCA1/p53(+/-), and C3(1)T-Ag mice were transplanted into the mammary fat pad or s.c. into naïve syngeneic or immunosuppressed mice. Tumor development was monitored and tissues were processed for histopathology and gene expression profiling. Metastasis was scored 60 days after the removal of transplanted tumors. RESULTS: PyMT tumor fragments and cell suspensions from anterior glands grew faster than posterior tumors in serial passages regardless of the site of implantation. Microarray analysis revealed genetic differences between these tumors. The transplantation was reproducible using anterior tumors from multiple GEM, and tumor growth rate correlated with the number of transplanted cells. Similar morphologic appearances were observed in original and transplanted tumors. Metastasis developed in >90% of mice transplanted with PyMT, 40% with BRCA1/p53(+/-) and wnt1/p53(+/-), and 15% with Her2/neu tumors. Expansion of PyMT and wnt1 tumors by serial transplantation for two passages did not lead to significant changes in gene expression. PyMT-transplanted tumors and anterior tumors of transgenic mice showed similar sensitivities to cyclophosphamide and paclitaxel. CONCLUSIONS: Transplantation of GEM tumors can provide a large cohort of mice bearing mammary tumors at the same stage of tumor development and with defined frequency of metastasis in a well-characterized molecular and genetic background.

Effect of vomeronasal organ removal from male mice on their preference for and neural Fos responses to female urinary odors.

Four experiments were conducted to determine whether vomeronasal organ (VNO) inputs in male mice mediate the rewarding properties of estrous female urinary odors. Sexually naive male mice with either an intact (VNOi) or lesioned (VNOx) VNO preferred to investigate female urine over water in Y-maze tests. Subsequently, VNOi males ran significantly more quickly and remained in nasal contact longer with estrous female urine than with male urine, whereas VNOx males investigated these odors equally. In home-cage habituation-dishabituation tests, VNOi males also investigated female urine significantly longer than did VNOx males, although both groups investigated female urine longer than other non-body odors. Finally, female urinary odors induced Fos in the nucleus accumbens core of VNOi males but not of VNOx males. Our results suggest that female urinary odors retain some incentive value in VNOx males. However, once direct nasal contact is made with female urine, VNO inputs further activate forebrain mechanisms that amplify the reward salience of this stimulus for the male mouse.

Accessory olfactory neural Fos responses to a conditioned environment are blocked in male mice by vomeronasal organ removal.

The ability of an anesthetized estrous female to induce a conditioned place preference (CPP) response was assessed in male mice from which the vomeronasal organ (VNO) had either been removed (VNOx) or left intact (VNOi) in an initial effort to assess the possible contribution of VNO-accessory olfactory inputs to the intrinsically rewarding properties of opposite-sex body odorants. Both VNOi and VNOx male mice acquired a CPP after repeated pairing of an initially non-preferred test chamber with an anesthetized estrous female mouse, suggesting that odorants detected by the main olfactory system and/or visual and tactile cues from the anesthetized estrous female can compensate for absent VNO inputs to establish a CPP. Subsequent exposure to this conditioning chamber alone caused significant increases in the number of Fos-immunoreactive cells in the mitral and granule cell layers of the accessory olfactory bulb as well as in the medial amygdala and ventral tegmental area of VNOi but not of VNOx males. These results suggest that activity in distal segments of the VNO-accessory olfactory pathway, in addition to the mesolimbic dopamine reward system, can be conditioned to respond to non-odor cues.