Expression of the Bcl-2 protein in nasal epithelia of F344/N rats during mucous cell metaplasia and remodeling

Exposure to ozone induces mucous cell metaplasia in rat airway epithelia. During the regeneration process, apoptotic mechanisms may be responsible for eliminating metaplastic cells. Therefore, the present study investigated expression of Bcl-2, a regulator of apoptosis, in ozone-induced mucous cell metaplasias. Adjacent metaplastic mucous cells in nasal airway epithelia that were exposed to ozone were heterogeneous in their expression of Bcl-2; some cells expressed high levels, whereas others expressed low levels or no Bcl-2. On Western blot analysis, Bcl-2 was detected in protein extracts from nasal epithelia of rats exposed to 0.5 ppm ozone for 1 mo but not in control rats exposed to filtered air. The number of metaplastic mucous cells in transitional epithelia of rat nasal airways was increased from 0 to about 200 after 3 and 6 mo of exposure to ozone; only 0 to 10 metaplastic mucous cells remained after a recovery period of 13 wk in rats exposed to ozone for 3 mo. The number of mucous cells of the respiratory epithelium lining the midseptum did not change after ozone exposure or recovery. The percentage of Bcl-2-positive cells lining the midseptum increased from 7 to 14% after a 3- and 6-mo ozone exposure, respectively. In transitional epithelia of the lateral wall and the nasoturbinates and maxilloturbinates, 35 to 55% of cells were Bcl-2-positive after a 1-mo exposure and 10 to 18% after both a 3- and a 6-mo exposure to ozone. Bcl-2 reactivity decreased to 0 to 8% after a recovery period of 13 wk. These observations suggest that Bcl-2 plays a role in the development and resolution of mucous cell metaplasias. This model may be useful in uncovering the role of Bcl-2 during the development and maintenance of metaplastic mucous cells. Disregulation of Bcl-2 expression may be responsible for the sustained mucous cell metaplasia in asthmatics or may allow cells to accumulate and become more susceptible to transformation leading to neoplasia.     

S100B, a neurotropic protein that modulates neuronal protein phosphorylation, is upregulated during lesion-induced collateral sprouting and reactive synaptogenesis

Using light and electron microscopic immunocytochemistry, we examined the expression of the Ca2+-binding protein S100B in the dentate gyrus of adult rats during lesion-induced sprouting and reactive synaptogenesis. Nine days following unilateral lesioning of the entorhinal cortex, S100B was upregulated in cells primarily in the outer part of the molecular layer of the ipsilateral dentate gyrus. When examined with electron microscopy, numerous astrocytes and synapses containing S100B were identified. These data show that during lesion-induced sprouting and reactive synaptogenesis, S100B is upregulated in astrocytes and can be found in pre- and post-synaptic compartments where it might influence neuronal protein phosphorylation.     

A role for BDNF in early postnatal rat vestibular epithelia maturation: implication of supporting cells

The early development of the inner ear is largely determined by two members of the neurotrophic family: brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3). Little information is available on the role of these neurotrophins during the late stages of vestibular development in the rat which take place during the first postnatal weeks. At this period where terminal synaptogenesis and maturation occur, we have investigated the expression and the activity of BDNF, the most important neurotrophin in the vestibular system. Using different experimental approaches, we show that BDNF is released by vestibular epithelia on postnatal day 3 (P3) and continues to have a trophic effect on vestibular neurones in vitro. Immunocytochemistry coupled to confocal microscopy revealed a remarkable evolution in BDNF localization during later stages of development. Whereas BDNF is present in both supporting cells and hair cells at P3, its distribution gradually changed and is highly compartmentalized within the upper part of supporting cells at P8 and P15. In parallel, we observed the presence of a truncated form of the BDNF receptor in sensory hair cells. These results suggest an original role for supporting cells, which could be involved in the release of BDNF during the late stages of synaptogenesis in mammalian vestibular epithelia. In particular, BDNF could participate to the set up of the calyx, a specific nerve structure surrounding type I vestibular hair cells.     

SC1: a marker for astrocytes in the adult rodent brain is upregulated during reactive astrocytosis

An amino acid index is a set of 20 numerical values representing any of the different physicochemical and biochemical properties of amino acids. As a follow-up to the previous study, we have increased the size of the database, which currently contains 402 published indices, and re-performed the single-linkage cluster analysis. The results basically confirmed the previous findings. Another important feature of amino acids that can be represented numerically is the similarity between them. Thus, a similarity matrix, also called a mutation matrix, is a set of 20 x 20 numerical values used for protein sequence alignments and similarity searches. We have collected 42 published matrices, performed hierarchical cluster analyses and identified several clusters corresponding to the nature of the data set and the method used for constructing the mutation matrix. Further, we have tried to reproduce each mutation matrix by the combination of amino acid indices in order to understand which properties of amino acids are reflected most. There was a relationship between the PAM units of Dayhoff's mutation matrix and the volume and hydrophobicity of amino acids. The database of 402 amino acid indices and 42 amino acid mutation matrices is made publicly available on the Internet.     

The MEK1 proline-rich insert is required for efficient activation of the mitogen-activated protein kinases ERK1 and ERK2 in mammalian cells

MEK1 and MEK2 contain a proline-rich insert not present in any other known MEK (MAP (mitogen-activated protein)/ERK (extracellular signal-regulated kinase) kinase) family members. We examined the effect of removing the MEK1 polyproline insert on MEK activity, its binding to Raf, and its ability to activate ERKs in cells. Deletion of the insert had no effect on either the activity of MEK1 or on its ability to bind to Raf-1. Both wild type and constitutively active MEK1 coimmunoprecipitated with Raf-1 whether or not the insert was present. Deletion of the insert did not reduce activation of MEK1 by EGF or activated Raf in cells. The proline-rich insert enhanced the ability of an otherwise equally active MEK1 protein to regulate endogenous ERKs in mammalian cells. Overexpression of either constitutively active MEK1 lacking the insert or ERK2 compensates for the weaker in vivo activity of the MEK1 deletion mutant. Expression of the insert in cells reduced activation of ERKs by EGF. We conclude that the proline-rich insert is not the site of the MEK-Raf interaction and that the polyproline insert is required for its efficient activation of downstream ERKs in cells.     

Cyclin D1 protein expression is related to clinical progression in laryngeal squamous cell carcinomas

The expression of cyclin D1 gene was investigated in 74 laryngeal squamous cell carcinomas (LSCCs) in order to determine its clinical and prognostic value. Overexpression of cyclin D1 was detected immunohistochemically using DCS6 monoclonal antibody on formalin-fixed, paraffin-embedded tissue sections. Cyclin D1 expression was detected in 22 of the 74 cases investigated (30 per cent), thirteen of which presented nodal metastases (59 per cent); of the patients without any detectable cyclin D1 protein expression, six presented nodal metastases (12 per cent). Cyclin D1 protein expression was found in five per cent of the specimens of normal mucosa, eight per cent of those with low-grade dysplasia and 20 per cent of those with high-grade dysplasia. A statistically significant association was found between cyclin D1 expression and the supraglottic site (p < 0.05), tumour extension (p < 0.001), the presence of lymph node metastases (p < 0.001), and advanced clinical stage (p < 0.001). Cyclin D1 expression analysis is an important tool in the selection of LSCC patients with an aggressive clinical course.     

The effects of phenethyl isothiocyanate, N-acetylcysteine and green tea on tobacco smoke-induced lung tumors in strain A/J mice

Male and female strain A/J mice were exposed to a mixture of cigarette sidestream and mainstream smoke at a chamber concentration of total suspended particulates of 82.5 mg/m3. Exposure time was 6 h/day, 5 days/week for 5 months. The animals were allowed to recover for another 4 months in filtered air before sacrifice and lung tumor count. Male animals were fed either 0.2% N-acetylcysteine (NAC) or 0.05% phenethyl isothiocyanate (PEITC) in diet AIN-76A with 5% corn oil added. Female animals received normal laboratory chow and were given a 1.25% extract of green tea in the drinking water. Corresponding control groups were fed diets without NAC or PEITC or given plain tap water. Exposure to tobacco smoke increased lung tumor multiplicity to 1.1-1.6 tumors/lung, significantly higher than control values (0.5-1.0 tumors/lung). None of the putative chemopreventive agents (NAC, PEITC or green tea extract) had a protective effect. In positive control experiments, PEITC significantly reduced both lung tumor multiplicity and incidence in mice treated with the tobacco smoke-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In mice treated with three different doses of urethan and fed NAC in the diet, a significant reduction in lung tumor multiplicity was found only at one dose level. Green tea extract did not reduce lung tumor multiplicity in animals treated with a single dose of NNK. It was concluded that successful chemoprevention of tobacco smoke-induced lung tumorigenesis might require administration of several chemopreventive agents rather than just a single one.     

A microtubule-associated protein in maize is expressed during phytochrome-induced cell elongation

Plants can adapt their shape to environmental stimuli. This response is mediated by the reorganization of cortical microtubules, a unique element of the cytoskeleton. However, the molecular base of this response has remained obscure so far. In an attempt to solve this problem, signal-dependent changes in the pattern of microtubule-binding proteins were analysed during coleoptile elongation in maize, that is, under the control of the plant photoreceptor phytochrome. Two putative MAPs of 100 kDa (P100) and 50 kDa apparent molecular weights were identified in cytosolic extracts from non-elongating and elongating cells. Both proteins co-assembled with endogenous tubulin, bound to neurotubules and were immunologically related to the neural MAP tau: the P100 protein, depending on the physiological situation, was manifest as a double band and was always found to be heat-stable. In contrast, the 50 kDa MAP was heat-stable only for particular tissues and physiological treatments. The P100 protein was present in all tissues, however in a reduced amount in elongating coleoptiles. The 50 kDa MAP was expressed exclusively upon induction of phytochrome-dependent cell elongation. As shown by immunofluorescence double-staining, an epitope shared by both proteins colocalized with cortical microtubules in situ, but exclusively in elongating cells. In non-elongating cells, only the nuclei were stained. Partially purified nuclei from elongating cells were enriched in P100, whereas the 50 kDa MAP became enriched in a partially purified plasma membrane fraction.     

The small GTP-binding protein Rho1 is a multifunctional protein that regulates actin localization, cell polarity, and septum formation in the fission yeast Schizosaccharomyces pombe

BACKGROUND: The small GTP-binding protein Rho has been shown to regulate the formation of the actin cytoskeleton in animal cells. We have previously isolated two rho genes, rho1+ and rho2+, from the fission yeast Schizosaccharomyces pombe in order to investigate the function of Rho using genetic techniques. In this paper, we report the cellular function of Rho1. RESULTS: We found that Rho1 is essential for cell viability and cell polarity using gene disruption and by exogenous expression of botulinum C3 ADP-ribosyltransferase. In cells expressing either a constitutively active Rho1 or a dominant-negative Rho1, actin patches were delocalized. Both the cell wall and secondary septum were thick and stratified in cells expressing the constitutively active Rho1, while the cell wall of cells expressing the dominant-negative Rho1 seemed to be loosely organized. Furthermore, inactivation of Rho1 is apparently required for the separation of daughter cells. Cell fractionation studies suggested that Rho1 is predominantly membrane-bound. Moreover, we observed that Rho1 is localized to the cell periphery and to the septum. CONCLUSIONS: Rho1 is involved in actin patch localization, the control of cell polarity, the regulation of septation, and cell wall synthesis.     

The antipsychotic drug sertindole is a specific inhibitor of alpha1A-adrenoceptors in rat mesenteric small arteries

One of the goals of baccalaureate nursing education is to facilitate students' cognitive development, that is, their ability to employ reason, manage diversity, and engage in contextual decision-making. Despite this goal, however, studies indicate that the majority of nursing students tend to be at the lower levels of development, rather than at more advanced levels. The purpose of the study reported here was to describe the cognitive development of one university's nursing student population at the beginning and end of the freshman year, investigate the effects of planned developmental instruction strategies on cognitive growth, and investigate the relationship among cognitive development, GPA, and SAT scores. While subjects evidenced some cognitive growth, the mean level of cognitive development for all subjects was at the lower end of the scale. Specific instructional strategies are described, statistical and qualitative analyses of groups are reported, and suggestions for further research are proposed.     

p53, but not p16 mutations in oral squamous cell carcinomas are associated with specific CYP1A1 and GSTM1 polymorphic genotypes and patient tobacco use

Inactivation of tumor suppressor genes like p53 and p16 play a key role in tumor progression, with a high incidence of mutations existing for both genes in oral squamous cell carcinomas. Previous studies have demonstrated, (i) a correlation between the prevalence of p53 mutations and tobacco use [Brennan et al. (1995) New Engl. J. Med., 332, 712-717; Lazarus et al. (1996) Carcinogenesis, 17, 733-739], and (ii) a link between genotypes in specific xenobiotic metabolizing enzymes and oral cancer susceptibility [Park et al. (1997) Cancer Epid. Biomarkers Prev., 6, 791-797). In this paper, we present results of our examination of a series of 80 oral squamous cell carcinomas for p53 exons 5-9 and p16 exons 1-2 mutations, and the potential association of these mutations with specific genotyping patterns. p53 mutation prevalence in oral tumors was linked with increased patient tobacco use using several stratification criteria. There was a significantly higher prevalence of p53 mutations in OCSCCs from patients who smoked > 30 pack-years as compared to tumors from patients who smoked < or = 30 pack-years (OR = 2.8; CI = 1.1-7.2). No significant association was observed with patient alcohol consumption. There was a significant association between the prevalence of p53 mutations in oral tumors and CYP1A1 genotyping patterns in these oral cancer patients, with the highest p53 mutation prevalence observed in subjects with the CYP1A1 [val]/GSTM1 [+] genotype (OR = 6.0; CI = 1.2-29.7). A significant association was not observed between the prevalence of p16 mutations in oral tumors and tobacco use, or CYP1A1 [val] or GSTM1 (0/0) genotypes. These data suggest that the induction of mutations in specific tumor suppressor genes or oncogenes in oral tumors may be associated with specific carcinogen exposures, and that this association may be linked to specific polymorphic genotypes in xenobiotic-metabolizing enzyme genes.     

Expression of rac1 protein in the crypt-villus axis of rat small intestine: in reference to insulin action

A programmable preemphasis system has been developed for eddy-current compensation in gradient sets with or without active screening. Preemphasis parameters are nonvolatile but can be changed rapidly when working with interchangeable gradient sets. The design allows easy retrofit to existing systems. A method for setting the preemphasis is presented, together with specimen results.     

Tachycitin, a small granular component in horseshoe crab hemocytes, is an antimicrobial protein with chitin-binding activity

Small granules of horseshoe crab hemocytes contain two known major antimicrobial substances, tachyplesin and big defensin (S5), and at least five protein components (S1 to S6), with unknown functions. In the present study, we examined the biological properties and primary structure of a small granular component S2, named tachycitin. This component was purified from the acid extract of hemocyte debris by two steps of chromatography. The purified tachycitin was a single chain protein with an apparent M(r) = 8,500 on Tricine-SDS-polyacrylamide gel electrophoresis. Ultracentrifugation analysis revealed tachycitin to be present in monomer form in solution. Tachycitin inhibited the growth of both Gram-negative and -positive bacteria, and fungi, with a bacterial agglutinating property. Moreover, tachycitin and big defensin acted synergistically in antimicrobial activities. The amino acid sequence and intrachain disulfide bonds of tachycitin were determined by amino acid and sequence analyses of peptides produced by enzymatic cleavages. The mature tachycitin consisted of 73 amino acid residues containing five disulfide bonds with no N-linked sugar. A cDNA coding for tachycitin was isolated from a hemocyte cDNA library. The open reading frame coded for an NH2-terminal signal sequence followed by the mature peptide and an extension sequence of -Gly-Arg-Lys at the COOH-terminus, which is a putative amidating signal. The COOH-terminal threonine amide released after digestion of tachycitin with lysylendopeptidase was identified. The NH2-terminal 28 residues of tachycitin shows sequence homology to a part of chitin-binding regions found in antifungal chitin-binding peptides, chitin-binding lectins, and chitinases, all of which have been isolated from plants. Tachycitin showed a specific binding to chitin but did not bind with the polysaccharides cellulose, mannan, xylan, and laminarin. Tachycitin may represent a new class of chitin-binding protein family in animals.     

p21 (WAF1/CIP1) expression is induced in newly nondividing cells in diverse epithelia and during differentiation of the Caco-2 intestinal cell line

The incidence of brain metastases secondary to small cell lung cancer (SCLC) is about 35% and the treatment strategy of brain irradiation with respect to dose and fractionation is controversial. In order to evaluate treatment outcome of brain irradiation in SCLC patients with brain relapse, we retrospectively evaluated all patients treated with brain irradiation in the eastern part of Denmark from 1988 to 1992 (PCI patients excluded). During this 5-year period, 101 evaluable patients were included (44 females, 57 males) (median age 61 years; range, 39-75 years). Forty-four patients, of whom 43 were in extracerebral complete remission (CR), received extended course (EC) brain irradiation (> 45 Gy, treatment schedule > 4 weeks). Fifty-seven patients received short course (SC) brain irradiation (< 30 Gy, treatment schedule < 1 week). Among the SC treated patients, 14 were in CR, 20 had partial remission or stable disease and 23 had progressive extracerebral disease. The median survival (from diagnosis of brain metastases) in the group receiving irradiation with EC (44 patients) was 160 days (range, 74-2021 days), while the 57 patients treated with SC had a median survival of 88 days (range, 20-948 days) (P = 0.00001, Log-Rank analysis). In a subgroup of 14 patients in extracerebral CR, receiving SC irradiation, the median survival was 83 days (range, 15-948 days). When the latter patients were compared to the 43 patients in CR in the group treated with EC, a statistically significant difference was shown (P = 0.034, Log-Rank analysis). Using Cox-hazard regression analysis with backward elimination, liver metastases and poor performance status were adverse prognostic signs, although the only significant parameters of survival were gender (female vs. male, relative risk of dying 1 and 1.52, P = 0.05) and schedule of brain irradiation (extended course vs. short course, relative risk of dying, 0.36 and 1, P < 0.001). Extended course irradiation of brain relapse secondary to SCLC seems in general to be of limited value, although a significant prolonged survival at approximately 7 weeks, was obtained. The prolongation of survival does not seem worthwhile considering the length of treatment time (5-6 weeks) compared to SC treatment (1 week). However, the data do not permit evaluation of the quality of life of the patients. This retrospective evaluation suggests the need for randomized trials with carefully planned quality-of-life assessments.