Intercellular junctions between decidual cells in the growing deciduoma of the pseudopregnant rat uterus

An increased stability of liver lysosomes and mitochondria of burned, dehydrated and tumour-bearing rats has been found in the present investigations. Using biochemical criteria we were able to show that the membranes of liver subcellular particles of these animals become more resistent to the labilizing action of CCl4. The latter effect was confirmed by electron microscopic data. The tumour growth, dehydration and burning of rats as well as sleep deprivation, overheating, lanthanum and ruthenium red have been shown to cause changes in the activity of some enzyme-systems located in endoplasmic reticulum. The protective action of these chemical, pathological and stress factors against CCl4 produced damage to the cell organelles studied is discussed in relation to the activity of the drug metabolizing pathways; biochemical (modifying of some enzyme activity) as well as pharmacological (duration of hexobarbital sleep) data were used as criteria for the activity of these pathways.     

The effects of oophorectomy and female sex steroids on glucose kinetics in the rat

In the present study, we have analyzed the appearance and maturation of gamma/delta T cells, recognized with a new mAb V65, in the central and peripheral lymphoid organs of fetal, neonatal, and adult Wistar rats. Cytofluorometrical analysis demonstrated the first V65+ gamma/delta T cells in the thymus of 16-17-day embryonic rats, although by immunohistology, they were identified only in 19-day rat embryos in both the cortico-medullary border and thymic medulla. Phenotypically, gamma/delta thymocytes from fetal and neonatal thymus expressed CD3, CD2, and CD5, but only 60-80% were CD8+ and approximately 40-50% expressed the alpha chain (p55) of the IL-2R. In the periphery, the immunohistological study identified for the first time gamma/delta T cells in the splenic white pulp and the gut of 21-day fetal rats, where they occurred within the epithelium as well as in the lamina propria. After birth, gamma/delta lymphocytes appeared in the skin, where they were present as dendritic epidermal T cells in increasing numbers during postnatal life. Whereas these gamma/delta T cells formed the predominant T-cell population in the rat skin, gamma/delta T cells in peripheral lymphoid organs, BALT, or the gut only represented a minor T-cell population. These results are discussed in comparison to gamma/delta T cells of other vertebrate species.     

DNA polymerases in the rat pituitary gland. Effect of oestrogens and sulpiride

Changes in the activity of DNA polymerase and [3H]thymidine incorporation into the DNA of the anterior pituitary gland were studied in oestrogenized male and pregnant rats. The activities of DNA polymerases alpha and beta, extracted in Tris--HCl or in sodium phosphate buffer were characterized according to their optimum pH and sensitivity to N-ethyl-maleimide. In the Tris-soluble fraction DNA polymerase activity is almost exclusively alpha, while in the phosphate soluble fraction it is a mixture of alpha and beta. The administration of oestrogens to male rats increases [3H]thymidine incorporation and enhances the activity of DNA polymerases in the Tris-soluble fraction, while the activity of the phosphate-soluble enzyme does not change. Sulpiride administration results in a further increment of [3H]thymidine incorporation and of DNA polymerase activity in the Tris-soluble fraction. In pregnant rats sulpiride also produces an increment of DNA polymerase activity only in the Tris-soluble fraction. Thus, the activity of the Tris-soluble fraction from APG behaves as DNA polymerase alpha. This activity changes in parallel with [3H]thymidine incorporation into DNA which is an indication of cell proliferation in the gland. This is discussed with respect to a negative feedback mechanism between intracellular prolactin concentration and DNA synthesis in the APG.     

Development of the aging cell surface: a freeze-fracture analysis of gap junctions between human embryo fibroblasts aging in culture. A brief note

Gap junctions have been identified between cells in late passage cultures of human embryo fibroblasts using techniques of freeze-fracture and electron microscopy. The junctions are sparsely distributed, which may suggest a decrease in electrotonic and metabolic coupling with increased age in culture.     

The serum and pituitary prolactin variations under the influence of a pesticide substance in the male rat

Prolactin was measured in the serum and hypophysis of the male rat after five days of oral administration of malathion in suspension (200 mg/kg body), alone or associated with pimozide (a psychotropic drug). The release of prolactin observed in the group treated with malathion was lower (19.97 +/- 7.27 ng/ml) than in the groups treated with malathion and pimozide or pimozide alone (26.65 +/- 3.17 and 26.49 +/- 2.57 ng/ml, respectively) but significantly higher than in the control group (10.08 +/- 5.82 ng/ml). The administration of two dose levels of pure malathion solubilized in alcohol/water (v/v) failed to reproduce the same results. The discussions are focussed upon: 1) the mechanisms involved in the release of prolactin under the influence of malathion (vagomimetic action) and 2) the lack of cumulative effects of malathion and pimozide (presumably different levels of their influence).     

Studies on the posterior silk gland of the silkworm Bombyx mori. VI. Distribution of microtubules in the posterior silk gland cells

There are two microtubule systems in the posterior silk gland cells. One is a radial microtubule system in which the microtubules run radially from the basal to the apical cytoplasm and in which fibroin globules (secretory granules of fibroin) and mitochondria are arranged along these microtubules, thus composing a "canal system" which is assumed to be responsible for the intracellular transport of fibroin globules. The other is a circular microtubule system in the apical cytoplasm which is composed of bundles of microtubules and microfilaments running in a circular arrangement around the glandular lumen at an interval of approximately 4 mum at the end of the fifth instar. This system is presumably concerned with secretion and/or intraluminal transport of fibroin.     

Parotid gland tissue is able partially to assume pituitary functions under the influence of hypothalamic factors: in vivo and in vitro studies

To test whether salivary tissue can secrete pituitary hormones, female Sprague-Dawley rats were hypophysectomized (hypox) and the following were transplanted to the sella turcica: parotid gland (group 3, n=33), adrenal gland (group 4, n=30), muscle (group 5, n=24). Group 2 (n=21) had the sella turcica filled with dentist's cement. In addition a group of rats (group 1, n=22) remained intact as controls. All groups were followed for 8 months. Daily vaginal smears showed normal cyclicity in controls and constant dioestrus in all hypox groups. Blood samples, taken once every 30 days before and after LHRH stimulation, showed significantly lower (P<0.001) plasma LH values in all hypox groups compared with controls. In group 3, a gradual and significant increase (P<0.05) was observed in the LH response to LHRH in parallel with a partial recovery of oestrous smears. No LH modification was observed in the other hypox groups. Plasma prolactin (PRL) levels were also very low in all hypox groups and were unaltered throughout the study. At the end of the experiments, half the animals were killed by decapitation and the hypothalamic-pituitary areas carefully dissected, homogenized and analysed for LH and PRL content. The remaining animals were perfused with 4% paraformaldehyde to obtain fixing of the whole body tissues. Hypothalamic and transplant areas were carefully dissected, frozen, cut and submitted to immunochemical procedures. LH content in the graft of group 3 animals was markedly (P<0.001) lower than in the control pituitary, but significantly higher (P<0.05) than in the other hypox groups. Immunochemistry showed LH and PRL positive cells in the graft of group 3 animals, whereas neither positive cells, nor LH content were observed in the parotid gland in situ. Experiments were completed with in vitro cultures of parotid glands in the presence or absence (controls) of synthetic hypothalamic hormones or rat hypothalamic extracts. After 1.5 weeks of culture, a significantly higher LH concentration (P<0.05) was observed in the wells treated with synthetic hypothalamic hormones (216+/-46 pg/ml vs 41+/-6 pg/ml in controls). When hypothalamic extracts were used, the LH levels increased more markedly (1834+/-190 pg/ml vs 36+/-6 pg/ml in controls) and those values were maintained during 3 weeks of culture. Immunostaining of these cultures showed a positive LH reaction in the epithelial cells found in the hypothalamic extract-treated wells. Both in vivo and in vitro studies confirm the transdifferentiation of parotid gland tissue to pituitary hormone-producing cells under hypothalamic influence.     

Passover eliminates gap junctional communication between neurons of the giant fiber system in Drosophila. off

The Passover-related gene family plays significant roles in cellular connectivity. Mutations in three family members from Drosophila and from Caenorhabditis elegans alter a few specific electrical synapses. The passage of cobalt between Drosophila neurons was used to assay the presence of gap junctional connections. The giant fiber in the wild type has specific gap junctional connections in the brain and in the thorax. In flies mutant for Passover, cobalt cannot pass into or out of the giant fiber in either the anterograde or the retrograde directions. A large number of other gap junctional connections remain unaffected. This demonstrates that the Passover gene is necessary for gap-junctional communication between the neurons of the Drosophila giant fiber system.     

Two-way communication between the heart and the brain: Significance of time within the cardiac cycle.

Summarizes results of research dealing with time within the cardiac cycle as an experimental variable. In a variety of different experiments, meaningful sensorimotor events produced changes in heart rate that were systematically related to where in the cardiac cycle the events occurred. This function is proposed as a noninvasive measure in intact humans of cortically mediated effects on vagal control of the heart. Time within the cardiac cycle is also a dependent variable: Self-initiated responses are postponed to increasingly later times as momentary heart rate increases. It is hypothesized that this may result from visceral afferent feedback to the CNS via the baroreceptor nerves. Preliminary results are presented from acute cat experiments showing that changes in frequency of carotid sinus stimulation and differences in the direction of change affect the temporal pattern of discharge of the carotid sinus nerve. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrastructural and immunohistochemical studies of intralobular fibroblasts in human submandibular gland: the recognition of a 'CD34 positive reticular network' connected by gap junctions

In order to clarify the ultrastructural and immunophenotypic characteristics of intralobular stromal cells in the human submandibular gland, normal tissues were examined from 25 patients by conventional histology of wax sections, light microscope immunohistochemistry, conventional thin-sectioning transmission electron microscopy, immuno-electronmicroscopy (for the CD34 antigen) and scanning electron microscopy. Spindled stromal cells had abundant rough endoplasmic reticulum cisternae typical of fibroblasts. Some actin filaments and microtubules were seen, but the filaments lacked the focal densities of smooth-muscle, nor was a lamina present. Fibroblasts exhibited long slender processes which associated with other fibroblasts by means of gap junctions and with mononuclear cells (lymphocytes, plasma cells, macrophages) by means of close appositions of membrane. Immunoelectron microscopy for CD34 revealed positive staining over the fibroblast surfaces but not over the mononuclear cells. The novel observation of gap junctions suggests a tissue closely organized as a network in physical and perhaps physiological terms. This network also incorporates mononuclear cells. The possible role in immunosurveillance of this CD34-positive reticular network is discussed.     

Visual and vestibular influences on head-direction cells in the anterior thalamus of the rat.

As a rat navigates through space, head-direction cells provide an ongoing signal of its momentary directional heading. This directional signal is thought to be generated, in part, by a dead-reckoning mechanism that uses angular motion information to constantly update the directional representation. This study investigated what kinds of angular motion information might be used for dead reckoning. Anterior thalamic head-direction cells were recorded from rats in a rotatable, cylindrical chamber, which could independently deliver visual motion cues and vestibular cues. Results suggest that both of these angular motion cues have an influence on head-direction cells and may thus be used for dead reckoning. The authors conclude that vestibular and visual movement cues work interactively, along with visual landmarks and motor signals, to determine the directional frame of reference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of the thyroid gland in the rat fetus in vivo. An ultrastructural and radioautographic study

A study of the differentiation of the thyroid follicles was carried out in rat fetuses between day 14 of pregnancy, when cellular polarization begins and day 18, when completely formed follicular lumina are differentiated. After day 18, only the shape and the size of the lumina undergo modifications. The mechanism of folliculogenesis involves the participation of several structures. At 14 days of pregnancy, adherens type contact zones with membrane densification appear between the cells. These junctional zones spread out and form infoldings which deeply penetrate the cytoplasm. Golgi vesicles migrate to these zones and they fuse among themselves and with the contact membranes : follicular cavities result which can be recognized as soon as day 16 of pregnancy. A radioautographic study showed the beginning of iodide organification at 17 days 11 hours of pregnancy. From this time onward silver grains were seen over the follicular cavity, even it is still incompletely formed.     

Interfollicular fibroblasts in the human thyroid gland: recognition of a CD34 positive stromal cell network communicated by gap junctions and terminated by autonomic nerve endings

While epithelial structure and functions have been substantially investigated in many organs, the mesenchymal elements have received less attention. Compared with follicular epithelial cells, there are a few morphological studies on the stroma of human thyroid gland. In order to characterize more fully and assess its possible functions, 15 samples of surgical and autopsy human thyroid tissue were studied by classical histology, immunohistochemistry, transmission electron microscopy, electron microscopic immunohistochemistry, and scanning electron microscopy. In human thyroid gland, the interfollicular connective tissue surrounding the follicles contained collagenous matrix, fibroblasts, unmyelinated nerve fibers with Schwann cells, small blood vessels, lymphatics, lymphocytes, plasma cells, macrophages, and mast cells. At the ultrastructural level, gap junctions between the cytoplasmic processes of interfollicular fibroblasts constituted a novel observation. Immunohistochemistry using a monoclonal antibody against Cx43 confirmed the distribution of gap junctions between stromal fibroblastic cells, which was compatible with the ultrastructural findings. The frequent and intimate association of fibroblastic processes with nerve terminals was also shown. Interfollicular stromal fibroblasts also stained with CD34. The main constituent of the human thyroid stromal tissue was a CD34 positive reticular network involving fibroblasts, mononuclear cells and nerve terminals. It represents a highly ordered stroma, with potential structural and functional similarities to the stroma of bone marrow (Yamazaki and Allen, 1990).     

Relationship between the Golgi apparatus, GERL, and secretory granules in acinar cells of the rat exorbital lacrimal gland

The method of secretory granuleformation in the acinar cells of the rat exorbital lacrimal gland was studied by electron microscope morphological and cytochemical techniques. Immature secretory granules at the inner face of the Golgi apparatus were frequently attached to a narrow cisternal structure similar to GERL as described in neurons by Novikoff et al. (Novikoff, P. M., A. B. Novikoff, N. Quintana, and J.-J. Hauw. 1971. J. Cell Bio. 50:859-886). In the lacrimal gland. GERL was located adjacent to the inner Golgi saccule, or separated from it by a variable distance. Portions of GERL were often closely paralleled by modified cisternae of rough endoplasmic reticulum (RER), which lacked ribosomes on the surface adjacent to GERL. Diaminobenzidine reaction product of the secretory enzyme peroxidase was localized in the cisternae of the nuclear envelope, RER, peripheral Golgi vesicles, Golgi saccules, and immature and mature secretory granules. GERL was usually free of peroxidase reaction product or contained only a small amount. Thiamine pyrophosphatase reaction product was present in two to four inner Golgi saccules; occasionally, the innermost saccule was dilated and fenestrated, and contained less reaction product than the next adjacent saccule. Acid phosphatase (AcPase) reaction product was present in GERL, immature granules, and, rarely, in the innermost saccule, but not in the rest of the Golgi saccules. Thick sections of AcPase preparations viewed at 100 kV revealed that GERL consisted of cisternal, and fenestrated or tublular portions. The immature granules were attached to GERL by multiple connections to the tublular portions. These results suggest that, in the rat exorbital lacrimal gland, the Golgi saccules participate in the transport of secretory proteins, and that GERL is involved in the formation of secretory granules.     

Impact of a social influence intervention on condom use and sexually transmitted infections among establishment-based female sex workers in the Philippines: A multilevel analysis.

The authors assessed the relative impact of structural and social influence interventions on reducing sexually transmitted infections (STIs) and HIV risk behavior among female sex workers in the Philippines (N = 897). Four conditions included manager influence, peer influence, combined manager-peer influence, and control. Intervention effects were assessed at the establishment level in multilevel models because of statistical dependencies among women employed within the same establishments. Control group membership predicted greater perceived risk, less condom use, less HIV/AIDS knowledge, and more negative condom attitudes. Combination participants reported more positive condom attitudes, more establishment policies favoring condom use, and fewer STIs. Manager-only participants reported fewer STIs, lower condom attitudes, less knowledge, and higher perceived risk than peer-only participants. Because interventions were implemented at the city level, baseline and follow-up city differences were analyzed to rule out intervention effects due to preexisting differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Ovarian hormones and cognition in the aged female rat: I. Long-term, but not short-term, ovariectomy enhances spatial performance": Correction to Bimonte-Nelson et al. (2003).

Reports an error in "Ovarian Hormones and Cognition in the Aged Female Rat: I. Long-Term, but Not Short-Term, Ovariectomy Enhances Spatial Performance" by Heather A. Bimonte-Nelson, Rachel S. Singleton, Christopher L. Hunter, Kimber L. Price, Alfred B. Moore and Ann-Charlotte E. Granholm (Behavioral Neuroscience, 2003[Dec], Vol 117[6], 1395-1406). The fifth sentence of the abstract reads, "Aged rats exhibited estradiol and elevated progesterone levels comparable to those of young rats." The sentence should read as follows: "Aged rats exhibited similar estradiol and elevated progesterone levels compared with those of young rats." (The following abstract of the original article appeared in record 2003-10460-025.) Although research suggests that ovariectomy (ovx) is detrimental to spatial cognition in young rats, little work has evaluated the cognitive effects of ovx in aged rats. The authors investigated the effects of ovx in aged rats using the water radial-arm maze. In Study 1, young rats and aged rats receiving ovx 1.5 months before testing outperformed aged rats receiving sham surgery or ovx 21 days before testing. In Study 2, young rats and aged rats receiving ovx 2.0 or 6.0 months before testing outperformed aged sham rats. Aged rats exhibited estradiol and elevated progesterone levels comparable to those of young rats. The findings suggest that 1.5-6.0 months, but not 21 days, of ovx improves spatial memory in aged rats. The hypothesis that long-term ovarian hormone loss is detrimental to spatial memory in aged rats was not supported. The authors hypothesize that removal of elevated progesterone levels is related to the ovx-induced cognitive enhancement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pelvic and pudendal nerves influence the display of paced mating behavior in response to estrogen and progesterone in the female rat.

Two experiments examined whether the pudendal and pelvic autonomic nerves are important for pacing behavior shown by the female rat during mating. Ovariectomized female rats received bilateral transection of the pudendal (Pux), pelvic (Pex), or pudendal and pelvic (Pu?+?Pex) nerves, or were sham-operated. Lordotic behavior, precopulatory solicitations, postural adjustments, and pacing behavior were measured 14 days after nerve transection in Exp 1 after sequential treatment with estradiol benzoate (EB) and progesterone (P) and in Exp 2 on the day after 7 daily injections of EB. After combined EB and P treatment, disruption of pacing behavior occurred in Pex and Pu?+?Pex animals. After EB-only treatment, Pux animals as well as Pex and Pu?+?Pex animals showed decreased pacing behavior. Thus, afferent input via the pelvic nerve is important for the display of pacing behavior, and P may counteract the effects of autonomic nerve transection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of cell growth. II. Requirement of thyroid hormones for the in vivo estrogen-dependent growth of rat pituitary tumor cells

A subclone of rat pituitary tumor cells, designated GH3/C14, was isolated from the parent population of GH3 pituitary cells and was estrogen-dependent for growth in vivo. GH3/C14 cells inoculated into host animals formed tumors in intact females, estrogen-treated ovariectomized females, and estrogen-treated males, but not in untreated intact or castrated males, or untreated ovariectomized females. Exogenous treatment with estrogens supported tumor formation in male animals. Radioimmunoassay of the average serum estradiol concentrations that support tumor growth in intact females, estradiol-treated intact females, and estradiol-treated intact males gave values of 41 +/- 4, 1,130 +/- 150, and 730 +/- 140 pg/ml, respectively. Tumor formation by GH3/C14 cells inoculated into male animals was not supported by either exogenous progesterone or hydrocortisone acetate. Further, these two steroid hormones had no significant effect on the estrogen-promoted growth in males or females. Exogenous testosterone treatment promoted tumor formation in males and ovariectomized females, but dihydrotestosterone was completely ineffective. Radioimmunoassay of the serum from tumor-bearing animals and the medium from the cells in culture showed that the cells produced growth hormone in vivo and in vitro but did not produce measurable amounts of luteinizing hormone or follicle-stimulating hormone. The groth of GH3/C14 cells in culture was examined in medium without added estrogen, and with estradiol added to the level of either the normal intact female rat or the estradiol-treated animals. No direct growth stimulation by estrogens could be detected in culture; the data suggested an indirect growth control mechanism.