The Olfactory Organ Is a Unique Site for Neutrophils in the Brain.

In the vertebrate olfactory tract new neurons are continuously produced throughout life. It is widely believed that neurogenesis contributes to learning and memory and can be regulated by immune signaling molecules. Proteins originally identified in the immune system have subsequently been localized to the developing and adult nervous system. Previously, we have shown that olfactory imprinting, a specific type of long-term memory, is correlated with a transcriptional response in the olfactory organs that include up-regulation of genes associated with the immune system. To better understand the immune architecture of the olfactory organs we made use of cell-specific fluorescent reporter lines in dissected, intact adult brains of zebrafish to examine the association of the olfactory sensory neurons with neutrophils and blood-lymphatic vasculature. Surprisingly, the olfactory organs contained the only neutrophil populations observed in the brain; these neutrophils were localized in the neural epithelia and were associated with the extensive blood vasculature of the olfactory organs. Damage to the olfactory epithelia resulted in a rapid increase of neutrophils both within the olfactory organs as well as the central nervous system. Analysis of cell division during and after damage showed an increase in BrdU labeling in the neural epithelia and a subset of the neutrophils. Our results reveal a unique population of neutrophils in the olfactory organs that are associated with both the olfactory epithelia and the lymphatic vasculature suggesting a dual olfactory-immune function for this unique sensory system.

The influence of increased water temperature on the duration of spermatogenesis in a neotropical fish, Astyanax altiparanae (Characiformes, Characidae).

In view of the established climate change scenario and the consequent changes in global temperature, it is essential to study its effects on animal spermatogenesis. Therefore, the aim of this study was to verify the duration of spermatogenesis at different temperatures. For this purpose, 96 male and adult specimens of Astyanax altiparanae were kept in a closed circulation system with water temperature stabilized at 27 °C and 32 °C. Subsequently, the specimens received pulses of BrdU (bromodeoxyuridine) at a concentration of 100 mg/kg/day for 2 consecutive days, and the samples were collected daily for a period of 15 days. Their testes were removed, fixed, processed in historesin, and sectioned in 3 µm, submitted to hematoxylin/eosin staining and to bromodeoxyuridine immunodetection. Partial results of the optimum temperature experiments allowed the classification of A. altiparanae spermatogenic cells in Aund, Adiff, and type B spermatogonia, spermatocytes, spermatids, and spermatozoa. The duration of spermatogenesis was determined as approximately 6 days for animals at a temperature of 27 °C and 1 day for animals at 32 °C. The elevated temperature was also responsible for increasing cell proliferation, resulting in an increase in the number of spermatocytes, spermatids, spermatozoa, and cell death (cell pyknotic). The duration of spermatogenesis in A. altiparanae was directly affected by the elevated water temperature, causing a reduction in the estimated time of spermatogenesis.

Duration of the seminiferous epithelium cycle in the frugivorous bat Artibeus lituratus.

The seminiferous epithelium goes through multiple changes which enables the differentiation of a spermatogonia in a fully mature spermatozoon. The timing of these changes is species-specific and influences the duration of the reproductive cycles. Bats are among wild mammals whose coordination between male and female reproductive cycles are imperative, since most females show seasonal preferences, even in the Tropics. This seasonal variation demands constant sperm production ready for spermiation in order to guarantee its genetic dispersion and reproduction success. Despite their abundance, little is known about the duration of reproductive cycles in Neotropical bat species, a relevant information for the species management and for conservational strategies regarding anthropogenic and climate influences on bats reproduction. In this study, we aimed at characterizing the stages of the seminiferous epithelium cycle (SEC) of the fruit bat Artibeus lituratus and to determine its duration based on the immunohistochemical analysis of the bromodeoxyuridine (BrDU) activity. SEC stages were characterized according to the tubular morphology method and the frequency of each stage was estimated. After intratesticular injections of BrDU, the animals were euthanized at different times, and the estimation of SEC duration was performed by observing the most advanced germ cells in the seminiferous epithelium. The most advanced stained cells after 2 days of BrdU injection were the primary spermatocytes in pachytene, transitioning from stages 1-2 of the SEC. Within 2 days, we found a progression of 30.42% of the SEC, and an entire cycle lasted 6.58 days on average. Considering that 4.5 seminiferous epithelium cycles are necessary for the whole spermatogenic processes to be completed, the total length of spermatogenesis in A. lituratus was estimated at 29.61 days. Our findings support a pattern of bimodal seasonal polyestry for this species, with rapid spermatogenic cycles.

Running wheel training does not change neurogenesis levels or alter working memory tasks in adult rats.

BACKGROUND: Exercise can change cellular structure and connectivity (neurogenesis or synaptogenesis), causing alterations in both behavior and working memory. The aim of this study was to evaluate the effect of exercise on working memory and hippocampal neurogenesis in adult male Wistar rats using a T-maze test. METHODS: An experimental design with two groups was developed: the experimental group (n = 12) was subject to a forced exercise program for five days, whereas the control group (n = 9) stayed in the home cage. Six to eight weeks after training, the rats' working memory was evaluated in a T-maze test and four choice days were analyzed, taking into account alternation as a working memory indicator. Hippocampal neurogenesis was evaluated by means of immunohistochemistry of BrdU positive cells. RESULTS: No differences between groups were found in the behavioral variables (alternation, preference index, time of response, time of trial or feeding), or in the levels of BrdU positive cells. DISCUSSION: Results suggest that although exercise may have effects on brain structure, a construct such as working memory may require more complex changes in networks or connections to demonstrate a change at behavioral level.

Inherited Xq13.2-q21.31 duplication in a boy with recurrent seizures and pubertal gynecomastia: Clinical, chromosomal and aCGH characterization.

We report on a 16-year-old boy with a maternally inherited ~ 18.3 Mb Xq13.2-q21.31 duplication delimited by aCGH. As previously described in patients with similar duplications, his clinical features included intellectual disability, developmental delay, speech delay, generalized hypotonia, infantile feeding difficulties, self-injurious behavior, short stature and endocrine problems. As additional findings, he presented recurrent seizures and pubertal gynecomastia. His mother was phenotypically normal and had completely skewed inactivation of the duplicated X chromosome, as most female carriers of such duplications. Five previously reported patients with partial Xq duplications presented duplication breakpoints similar to those of our patient. One of them, a fetus with multiple congenital abnormalities, had the same cytogenetic duplication breakpoint. Three of the reported patients shared many features with our proband but the other had some clinical features of the Prader-Willi syndrome. It was suggested that ATRX overexpression could be involved in the major clinical features of patients with partial Xq duplications. We propose that this gene could also be involved with the obesity of the patient with the Prader-Willi-like phenotype. Additionally, we suggest that the PCDH11X gene could be a candidate for our patient's recurrent seizures. In males, the Xq13-q21 duplication should be considered in the differential diagnosis of Prader-Willi syndrome, as previously suggested, and neuromuscular diseases, particularly mitochondriopathies.

DNA synthesis in periportal and perivenous hepatocytes of intact and hepatectomized young mice.

DNA synthesis of hepatocytes in two areas of Intact and Hepatectomized young mice liver along a circadian period was studied. DNA synthesis was significantly different at all analyzed time points in Intact and Hepatectomized animals. Differences between periportal and perivenous hepatocytes were found in hepatectomized animals at 04/42 and 08/46 hr of day/hour post-hepatectomy. DNAs peak in periportal hepatocytes regenerating liver occurs 4 hr earlier than in perivenous hepatocytes, probably reflecting their shorter G1 phase. Besides, daily mean values of regenerating livers were higher than those observed in Intact animals, as a consequence of surgical removal.

Cdc42 coordinates proliferation, polarity, migration, and differentiation of small intestinal epithelial cells in mice.

BACKGROUND & AIMS: Cdc42 is a Rho GTPase that regulates diverse cellular functions, including proliferation, differentiation, migration, and polarity. In the intestinal epithelium, a balance among these events maintains homeostasis. We used genetic techniques to investigate the role of Cdc42 in intestinal homeostasis and its mechanisms. METHODS: We disrupted Cdc42 specifically in intestinal epithelial cells by creating Cdc42flox/flox-villin-Cre+ and Cdc42flox/flox-Rosa26-CreER+ mice. We collected intestinal and other tissues, and analyzed their cellular, molecular, morphologic, and physiologic features, compared with the respective heterozygous mice. RESULTS: In all mutant mice studied, the intestinal epithelium had gross hyperplasia, crypt enlargement, microvilli inclusion, and abnormal epithelial permeability. Cdc42 deficiency resulted in defective Paneth cell differentiation and localization without affecting the differentiation of other cell lineages. In mutant intestinal crypts, proliferating stem and progenitor cells increased, compared with control mice, resulting in increased crypt depth. Cdc42 deficiency increased migration of stem and progenitor cells along the villi, caused a mild defect in the apical junction orientation, and impaired intestinal epithelium polarity, which can contribute to the observed defective intestinal permeability. The intestinal epithelium of the Cdc42flox/flox-villin-Cre+ and Cdc42flox/flox-Rosa26-CreER+ mice appeared similar to that of patients with microvillus inclusion disease. In the digestive track, loss of Cdc42 also resulted in crypt hyperplasia in the colon, but not the stomach. CONCLUSIONS: Cdc42 regulates proliferation, polarity, migration, and differentiation of intestinal epithelial cells in mice and maintains intestine epithelial barrier and homeostasis. Defects in Cdc42 signaling could be associated with microvillus inclusion disease.

Perinatal exposure to diethylstilbestrol alters the functional differentiation of the adult rat uterus.

The exposure to endocrine disrupters and female reproductive tract disorders has not been totally clarified. The present study assessed the long-term effect of perinatal (gestation+lactation) exposure to diethylstilbestrol (DES) on the rat uterus and the effect of estrogen replacement therapy. DES (5µg/kg bw/day) was administered in the drinking water from gestational day 9 until weaning and we studied the uterus of young adult (PND90) and adult (PND360) females. To investigate whether perinatal exposure to DES modified the uterine response to a long-lasting estrogen treatment, 12-month-old rats exposed to DES were ovariectomized and treated with 17ß-estradiol for 3 months (PND460). In young adult rats (PND90), the DES treatment decreased both the proliferation of glandular epithelial cells and the percentage of glandular perimeter occupied by α-smooth muscle actin-positive cells. The other tissue compartments remained unchanged. Cell apoptosis was not altered in DES-exposed females. In control adult rats (PND360), there were some morphologically abnormal uterine glands. In adult rats exposed to DES, the incidence of glands with cellular anomalies increased. In response to estrogens (PND460), the incidence of cystic glands increased in the DES group. We observed glands with daughter glands and conglomerates of glands only on PND460 and in response to estrogen replacement therapy, independently of DES exposure. The p63 isoforms were expressed without changes on PND460. Estrogen receptors α and ß showed no changes, while the progesterone receptor decreased in the subepithelial stroma of DES-exposed animals with estrogen treatment. The long-lasting effects of perinatal exposure to DES included the induction of abnormalities in uterine tissues of aged female rats and an altered response of the adult uterus to estradiol.

Apotransferrin-induced recovery after hypoxic/ischaemic injury on myelination.

We have previously demonstrated that aTf (apotransferrin) accelerates maturation of OLs (oligodendrocytes) in vitro as well as in vivo. The purpose of this study is to determine whether aTf plays a functional role in a model of H/I (hypoxia/ischaemia) in the neonatal brain. Twenty-four hours after H/I insult, neonatal rats were intracranially injected with aTf and the effects of this treatment were evaluated in the CC (corpus callosum) as well as the SVZ (subventricular zone) at different time points. Similar to previous studies, the H/I event produced severe demyelination in the CC. Demyelination was accompanied by microglial activation, astrogliosis and iron deposition. Ferritin levels increased together with lipid peroxidation and apoptotic cell death. Histological examination after the H/I event in brain tissue of aTf-treated animals (H/I aTF) revealed a great number of mature OLs repopulating the CC compared with saline-treated animals (H/I S). ApoTf treatment induced a gradual increase in MBP (myelin basic protein) and myelin lipid staining in the CC reaching normal levels after 15 days. Furthermore, significant increase in the number of OPCs (oligodendroglial progenitor cells) was found in the SVZ of aTf-treated brains compared with H/I S. Specifically, there was a rise in cells positive for OPC markers, i.e. PDGFRα and SHH(+) cells, with a decrease in cleaved-caspase-3(+) cells compared with H/I S. Additionally, neurospheres from aTf-treated rats were bigger in size and produced more O4/MBP(+) cells. Our findings indicate a role for aTf as a potential inducer of OLs in neonatal rat brain in acute demyelination caused by H/I and a contribution to the differentiation/maturation of OLs and survival/migration of SVZ progenitors after demyelination in vivo.