The protective action of zinc against the deleterious effects of cadmium in the regenerating forelimb of the adult newt, Notophthalmus viridescens

Peri-orbital puncture wounds by sharp wooden objects are not rare, but can be dangerous when there is intracranial penetration by and retention of the wooden foreign body. Days to years after an apparently trivial initial wounding, serious intracranial complications can occur. The authors have reviewed 42 case reports from the literature. Morbidity-defined as permanent neurologic sequelae-occurred in 74% of the cases. Intracranial suppuration was the major complication, with brain abscess having occurred in nearly one-half of the cases. Mortality occurred in 25% of 28 cases occurring in the post-antibiotic era. The qualities of wood which make it especially hazardous as a wounding agent and foreign body are discussed. The role of orbital anatomy in affording easy access to the cranial contents is described. Surgical exploration in all those cases in which there is a reasonable suspicion of intracranial injury is recommended.     

Prolactin delays gonadotrophin-induced ovulation and down-regulates expression of plasminogen-activator system in ovary

This study was conducted to determine whether prolactin (PRL) suppresses gonadotrophin-induced ovulation and disturbs the co-ordinated gene expression of tissue type plasminogen activator (tPA) and plasminogen activator inhibitor type-1 (PAI-1) in rat ovary. Immature female rats were injected with 10 IU pregnant mare's serum gonadotrophin to stimulate follicle growth, and 48 h received different doses of prolactin followed by 7 IU human chorionic gonadotrophin (HCG). The oviducts were examined for the presence of ova, and the amounts of tPA and PAI-1 mRNA present in the ovary were measured at various times after the hormone treatment. PRL had no significant effect on ovarian weight but caused a dose-dependent decrease in ovulation number. In the control animals receiving HCG alone, 13.3 +/- 1.3 (mean +/- SEM) ova/oviduct were found; while in animals receiving HCG plus 50, 100 or 200 microg PRL, the ovulation number was dose-dependently suppressed by 53.6, 66.9 and 76% respectively at 18 h after treatment. PRL suppression of HCG-induced ovulation was time-dependent. By 24 h after treatment, the number of ova in the oviducts in HCG- and HCG plus PRL-treated groups was not significantly different. PRL also suppressed HCG-induced tPA gene expression in a dose- and time-dependent manner. At all time points examined, tPA mRNA content of whole ovaries and granulosa cells (GC) in PRL-treated groups was lower than in the HCG-treated controls. The activities of PAI-1 in ovarian extracellular fluid (OEF) and PAI-1 mRNA in the theca-interstitial cells (TI) in the PRL-treated groups were higher than in the HCG-treated controls. The highest stimulation by PRL of PAI-1 activity in OEF and of PAI-1 mRNA in TI was observed at 9 h and 6 h after HCG treatment respectively. The localization of tPA and PAI-1 antigens in the ovaries was consistent with changes in the mRNA and activity levels. These data suggest that PRL temporarily delays, but does not completely inhibit, HCG-induced ovulation, which may be caused by a suppression of PA-mediated proteolysis.     

Prolactin, growth hormone and the immune system in humans

Prolactin (PRL) and growth hormone (GH) qualify as lymphoid growth and differentiation factors. Yet, long-standing hyper- or hyposecretion of PRL or GH does not induce any significant alteration of the immune system. Subclinical changes in laboratory parameters (such as chemotaxis or phagocytosis by granulocytes or macrophages or natural killer cell activity) have been reported in some of these conditions. The GH-insulin-like growth factor (IGF)-I axis is dysregulated in ageing, in catabolic states and in critical illness. Immune parameters, such as infection rate, are being monitored during clinical trials with GH or IGF-I. Hyperprolactinaemia may play an aggravating role in systemic lupus erythematosus, in autoimmune thyroiditis and in other autoimmune diseases. The patient may benefit from increased alertness about interactions between the endocrine and immune systems.     

Postnatal handling alters glucocorticoid, but not mineralocorticoid messenger RNA expression in the hippocampus of adult rats

Postnatal handling alters hypothalamic-pituitary-adrenal (HPA) responses to stress in the rat. Handling also increases hippocampal glucocorticoid receptor density, and this effect appears to form, in part at least, the basis for the effect of handling on HPA responsiveness to stress. In the present study we have used in situ hybridization techniques to examine the effect of postnatal handling on the expression of glucocorticoid and mineralocorticoid receptor mRNAs in various cell fields of the dorsal hippocampus in adult rats. Grain counting analysis over individual cells showed that postnatal handling significantly increased (40-50%) glucocorticoid receptor mRNA in all hippocampal cell fields. In contrast, handling had no effect on mineralocorticoid receptor mRNA expression. These findings are consistent with the results of receptor binding studies showing that handling increases hippocampal glucocorticoid receptor, but not mineralocorticoid receptor density. Thus, the increase in glucocorticoid receptor binding in handled animals is likely associated with altered rates of receptor biosynthesis. Moreover, the handling effect is quite specific, altering glucocorticoid receptor, but not mineralocorticoid receptor mRNA expression. The mechanism(s) whereby glucocorticoid receptor gene expression is permanently increased by postnatal handling remains to be determined.     

Lens-specific expression of PDGF-A alters lens growth and development

The vertebrate lens provides an in vivo model to study the molecular mechanisms by which growth factors influence development decisions. In this study, we have investigated the expression patterns of platelet-derived growth factor (PDGF) and PDGF receptors during murine eye development by in situ hybridization. Postnatally, PDGF-A is highly expressed in the iris and ciliary body, the ocular tissues closest to the germinative zone of the lens, a region where most proliferation of lens epithelial cells occurs. PDGF-A is also present in the corneal endothelium anterior to the lens epithelium in embryonic and early postnatal eyes. PDGF-B is expressed in the iris and ciliary body as well as in the vascular cells which surround the lens during early eye development. In the lens, expression of PDGF-alpha receptor (PDGF-alphaR), a receptor that can bind both PDGF-A and PDGF-B, is restricted to the lens epithelium throughout life. The expression of PDGF-alphaR in the lens epithelial cells and PDGF (A- and B-chains) in the ocular tissues adjacent to the lens suggests that PDGF signaling may play a key role in regulating lens development. To further examine how PDGF affects lens development in vivo, we generated transgenic mice that express human PDGF-A in the lens under the control of the alphaA-crystallin promoter. The transgenic mice exhibit lenticular defects that result in cataracts. The percentage of surface epithelial cells in S-phase is increased in transgenic lenses compared to their nontransgenic littermates. Higher than normal levels of cyclin A and cyclin D2 expression were also detected in transgenic lens epithelium. These results together suggest that PDGF-A can induce a proliferative response in lens epithelial cells. The lens epithelial cells in the transgenic mice also exhibit characteristics of differentiating fiber cells. For example, the transgenic lens epithelial cells are slightly elongated, contain larger and less condensed nuclei, and express fiber-cell-specific beta-crystallins. Our results suggest that PDGF-A normally acts as a proliferative factor for the lens epithelial cells in vivo. Elevated levels of PDGF-A enhance proliferation, but also appear to induce some aspects of the fiber cell differentiation pathway.     

Electron microscopic detection of glycoconjugates in the chicken lens

The cytochemical localization of glycoconjugates in the 14-day old embryonic chick lens was analysed by lectin-gold labelling. Con A/HRP gold particles, specific for D-mannose labelled the interior of the rough endoplasmic reticulum, membranes of the Golgi complex, secretory vesicles and the plasma membranes of the lens epithelial cell. The lens capsule was heavily labelled. Lens fiber cell membranes were also labelled. In contrast LFA, specific for neuraminic acid, did not bind to the endoplasmic reticulum or nuclear membrane. Labelling of the Golgi complex, secretory vesicles and capsule was observed. The plasma membranes of epithelial and fiber cells were extensively labelled, and probably reflects the presence of glycolipids such as gangliosides.     

Ectopic expression of the maize homeobox gene liguleless3 alters cell fates in the leaf

The semidominant mutation Liguleless3-O (Lg3-O) causes a blade-to-sheath transformation at the midrib region of the maize (Zea mays L.) leaf. We isolated a full-length lg3 cDNA containing a knotted1-like family homeobox. Six Lg3-O partial revertant alleles caused by insertion of a Mutator (Mu) transposon and two deletion derivatives were isolated and used to verify that our knotted1-like cDNA corresponds to the LG3 message. In wild-type plants the LG3 mRNA is expressed in apical regions but is not expressed in leaves. In mutant plants harboring any of three dominant lg3 alleles (Lg3-O, -Mlg, and -347), LG3 mRNA is expressed in leaf sheath tissue, indicating that the Lg3 phenotype is due to ectopic expression of the gene. The Lg3-O revertant alleles represent two classes of Lg3 phenotypes that correlate well with the level of ectopic Lg3 expression. High levels of ectopic LG3 mRNA expression results in a severe Lg3 phenotype, whereas weak ectopic Lg3 expression results in a mild Lg3 phenotype. We propose that ectopic Lg3 expression early in leaf development causes the blade-to-sheath transformation, but the level of expression determines the extent of the transformation.     

Retinal ganglion cell depletion alters the phenotypic expression of GABA and GAD in the rat retina

We have looked at the phenotypic expression of gamma-aminobutyric acid (GABA) and the two isoforms of its synthetic enzyme [glutamic acid decarboxylase (GAD)-65 and -67] in adult rat retinas that had the superior colliculus, pretectum and optic tract lesioned unilaterally at birth. It has been shown previously that this type of manipulation induces retrograde degeneration of retinal ganglion cells presumably without affecting other intraretinal neurons. We present evidence that GABAergic amacrine cells are affected by such manipulation. The number of cells immunoreactive for GABA, GAD-65 and GAD-67 decreased in the inner nuclear layer. In the retinal ganglion cell layer, however, the number of GABA- and GAD-65-labelled cells increased, while the number of GAD-67-labelled cells did not change. Biochemical assay showed that overall GAD activity was not altered in retinas of lesioned animals. Our results support the notion that, while neonatal lesion reorganizes the expression of GABA and GAD in the retina, enzyme activity is maintained within normal levels.     

Cochlear ablation alters acoustically induced c-fos mRNA expression in the adult rat auditory brainstem

Expression of c-fos mRNA was studied in the adult rat brain following cochlear ablations by using in situ hybridization. In normal animals, expression was produced by acoustic stimulation and was found to be tonotopically distributed in many auditory nuclei. Following unilateral cochlear ablation, acoustically driven expression was eliminated or decreased in areas normally activated by the ablated ear, e.g., the ipsilateral dorsal and ventral cochlear nuclei, dorsal periolivary nuclei, and lateral nucleus of the trapezoid body and the contralateral medial and ventral nuclei of the trapezoid body, lateral lemniscal nuclei, and inferior colliculus. These deficits did not recover, even after long survivals up to 6 months. Results also indicated that neurons in the dorsal cochlear nucleus could be activated by contralateral stimulation in the absence of ipsilateral cochlear input and that the influence of the contralateral ear was tonotopically organized. Results also indicated that c-fos expression rose rapidly and persisted for up to 6 months in neurons in the rostral part of the contralateral medial nucleus of the trapezoid body following a cochlear ablation, even in the absence of acoustic stimulation. This response may reflect a release of constitutive excitatory inputs normally suppressed by missing afferent input or changes in homeostatic gene expression related to sensory deprivation. Instances of transient, surgery-dependent increases in c-fos mRNA expression in the absence of acoustic stimulation were observed in the superficial dorsal cochlear nucleus and the cochlear nerve root on the ablated side.     

Chromosome variation in two populations of the crested newt, Triturus cristatus carnifex, with different melanoma incidence

Morphometric analysis of the chromosomes of the crested newt, Triturus cristatus carnifex, was carried out for two populations, one from Rosate (Milan) and one from Bagnaia (Perugia), which differed in the prevalence of melanoma (2.9 and 0.8%, respectively). Chromosomes were arranged in pairs both by the cytologist and by a previously developed computer programme. The two populations had significant differences in the relative lengths of chromosomes 9 and 10, and in the arm ratio values of 6 and 11. Though the morphometric parameters of the other elements of the complement appeared to be similar, the Rosate population showed significantly higher chromosomal asymmetry. In the Rosate population, there was greater intra-population and intra-individual variability than in the Bagnaia population. The karyotype variations observed suggest that chromosomal rearrangement may have occurred.     

Hypomyelination alters K+ channel expression in mouse mutants shiverer and Trembler

Voltage-gated K+ channels are localized to juxtaparanodal regions of myelinated axons. To begin to understand the role of normal compact myelin in this localization, we examined mKv1.1 and mKv1.2 expression in the dysmyelinating mouse mutants shiverer and Trembler. In neonatal wild-type and shiverer mice, the focal localization of both proteins in axon fiber tracts is similar, suggesting that cues other than mature myelin can direct initial K+ channel localization in shiverer mutants. In contrast, K+ channel localization is altered in hypomyelinated axonal fiber tracts of adult mutants, suggesting that abnormal myelination leads to channel redistribution. In shiverer adult, K+ channel expression is up-regulated in both axons and glia, as revealed by immunocytochemistry, RNase protection, and in situ hybridization studies. This up-regulation of K+ channels in hypomyelinated axon tracts may reflect a compensatory reorganization of ionic currents, allowing impulse conduction to occur in these dysmyelinating mouse mutants.     

Methamphetamine alters prodynorphin gene expression and dynorphin A levels in rat hypothalamus

Chronic administration of morphine or cocaine affects opioid gene expression. To better understand the possible existence of common neuronal pathways shared by different classes of drugs of abuse, we studied the effects of methamphetamine on the gene expression of the opioid precursor prodynorphin and on the levels of peptide dynorphin A in the rat brain. Acute (6 mg/kg, intraperitoneally, i.p.) and chronic (6 mg/kg, i.p. for 15 days) methamphetamine markedly raised prodynorphin mRNA levels in the hypothalamus, whereas no effect was observed in the hippocampus. Dynorphin A levels increased after chronic treatment in the hypothalamus and in the striatum, whereas no significant changes were detected after acute treatment. These results indicate that methamphetamine affects prodynorphin gene expression in the hypothalamus, which may be an important site (also for its relevant neuroendocrine correlates) for opioidergic mechanisms activated by addictive drugs.     

Assessment of cell surface glycoconjugates in normal, benign and malignant human nasal mucosa

Aberrant glycosylation of proteins is a common characteristic of neoplastic changes. No reports exist relating cell surface glycoconjugates to normal, benign and malignant human nasal mucosa. Using lectin affinity histochemistry, glycoconjugate reactivities for peanut agglutinin (PNA), concanavalin A (Con A), Griffonia simplicifolia agglutinin II (GSA-II), soy bean agglutinin (SBA) and Ulex europaeus agglutinin l (UEA-I) were analysed in the following groups: normal, benign (polyp, papilloma, and inverted papilloma) and malignant (squamous cell carcinoma (SCC) alone, SCC arising in inverted papilloma, and adenocarcinoma). The positive rate of lectin staining was evaluated using a quantitative AutoCAD programme. We correlated glycoconjugate expression to clinical features, diagnosis, and malignant transformation. The positive rate of PNA after neuraminidase pre-treatment (NA-PNA) staining was higher in inverted papilloma, while all-negative in polyp and papilloma. NA-PNA staining may be used as a differential diagnostic tool. Both inverted papilloma portions and SCC portions of the SCC synchronized with inverted papilloma subjects showed similar Con A and NA-PNA staining patterns. The biological characteristics define inverted papilloma as a pre-malignant neoplasm. The positive rate of PNA staining was significantly higher in inverted papilloma (inverted papilloma transformed to SCC) compared to inverted papilloma alone. Hence, PNA staining may predict malignant transformation of inverted papilloma. However, further investigations are required to prove this possibly worthwhile prognostic marker.     

Computer-assisted analysis of chromosomes of the European crested newt

A computer programme has been developed for partly automating the process of chromosome analysis of the European crested newt (Triturus cristatus carnifex). Chromosome classifications made by the computer and by the cytologist have been compared for a sample of 130 spermatogonial metaphase. The twelve pairs of chromosomes have been classified into three groups. The overall error rate achieved by the computer was 14% for chromosome assignment to single pairs, and 3.8% for chromosome assignment to the proper group.     

Hunger alters the expression of acquired hedonic but not sensory qualities of food-paired odors in humans.

To test whether expression of hedonic and sensory odor qualities acquired by association with sweet and bitter tastes depend on hunger state, hungry volunteers experienced odors paired with sucrose, quinine, or water and then were tested under different hunger states manipulated with energy preloads. Acquired liking for sucrose-paired odors was evident following a low-energy or control preload but not a high-energy preload; however, odor sweetness increased in all preload conditions. Acquired dislike and increased bitterness of quinine-paired odors were independent of preloading. These data demonstrate hunger-dependent expression of acquired liking for flavors through flavor-flavor associations in humans and demonstrate independence between acquired hedonic and sensory qualities of odors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nature and distribution of mineral-binding, keratan sulfate-containing glycoconjugates in rat and rabbit bone

The presence of keratan sulfate (KS) and KS proteoglycans in bone has been demonstrated in birds and rabbits but comparison with other animal species has not been investigated. The nature and distribution of mineral-binding, KS-containing glycoconjugates in rat and rabbit bone were investigated with a monoclonal antibody (MAb 5D4) specific for KS. Mineral-binding proteins were extracted from the mineralized bone with 0.4 M EDTA without guanidine-HCl (E-extract). On Western blot analysis of SDS-polyacrylamide gel electrophoresis, rat E-extract gave a weak 5D4-reactive band, M(r) 66,000-68,000, whereas rabbit E-extract produced two major reactive populations of small and large molecular size; one population consisted of two closely spaced bands at M(r) 61,000-63,000 and 66,000-68,000, and the other population consisted of one band at approximately M(r) 200,000. The identity of KS chains was further established by the sensitivity of these bands to keratanase II (Bacillus sp. Ks 36) and endo-beta-galactosidase. Immunocytochemistry with MAb 5D4 showed that, in rat bone, staining associated with the mineral phase was limited to the walls of osteocytic lacunae and bone canaliculi, whereas the remainder of the mineralized matrix lacked staining. In contrast, in rabbit bone the staining was distributed over the entire portion of the mineralized matrix with focal accumulation of staining in the wall of the lacunocanalicular system. These results indicate that rat bone contains a mineral-binding, KS-containing glycoconjugate with preferential localization in the wall of the lacunocanalicular system, whereas rabbit bone contains at least two or possibly three types of KS-containing glycoconjugates distributed over the entire portion of the mineralized matrix.     

Defective expression of the DNA mismatch repair protein, MLH1, alters G2-M cell cycle checkpoint arrest following ionizing radiation

A role for the Mut L homologue-1 (MLH1) protein, a necessary component of DNA mismatch repair (MMR), in G2-M cell cycle checkpoint arrest after 6-thioguanine (6-TG) exposure was suggested previously. A potential role for MLH1 in G1 arrest and/or G1-S transition after damage was, however, not discounted. We report that MLH1-deficient human colon carcinoma (HCT116) cells showed decreased survival and a concomitant deficiency in G2-M cell cycle checkpoint arrest after ionizing radiation (IR) compared with genetically matched, MMR-corrected human colon carcinoma (HCT116 3-6) cells. Similar responses were noted between murine MLH1 knockout compared to wild-type primary embryonic fibroblasts. MMR-deficient HCT116 cells or embryonic fibroblasts from MLH1 knockout mice also demonstrated classic DNA damage tolerance responses after 6-TG exposure. Interestingly, an enhanced p53 protein induction response was observed in HCT116 3-6 (MLH1+) compared with HCT116 (MLH1-) cells after IR or 6-TG. Retroviral vector-mediated expression of the E6 protein did not, however, affect the enhanced G2-M cell cycle arrest observed in HCT116 3-6 compared with MLH1-deficient HCT116 cells. A role for MLH1 in G2-M cell cycle checkpoint control, without alteration in G1, after IR was also suggested by similar S-phase progression between irradiated MLH1-deficient and MLH1-proficient human or murine cells. Introduction of a nocodazole-induced G2-M block, which corrected the MLH1-mediated G2-M arrest deficiency in HCT116 cells, clearly demonstrated that HCT116 and HCT116 3-6 cells did not differ in G1 arrest or G1-S cell cycle transition after IR. Thus, our data indicate that MLH1 does not play a major role in G1 cell cycle transition or arrest. We also show that human MLH1 and MSH2 steady-state protein levels did not vary with damage or cell cycle changes caused by IR or 6-TG. MLH1-mediated G2-M cell cycle delay (caused by either MMR proofreading of DNA lesions or by a direct function of the MLH1 protein in cell cycle arrest) may be important for DNA damage detection and repair prior to chromosome segregation to eliminate carcinogenic lesions (possibly brought on by misrepair) in daughter cells.