Regulation of aquaporin-2 trafficking by vasopressin in the renal collecting duct. Roles of ryanodine-sensitive Ca2+ stores and calmodulin

In the renal collecting duct, vasopressin increases osmotic water permeability (P(f)) by triggering trafficking of aquaporin-2 vesicles to the apical plasma membrane. We investigated the role of vasopressin-induced intracellular Ca(2+) mobilization in this process. In isolated inner medullary collecting ducts (IMCDs), vasopressin (0.1 nm) and 8-(4-chlorophenylthio)-cAMP (0.1 mm) elicited marked increases in [Ca(2+)](i) (fluo-4). Vasopressin-induced Ca(2+) mobilization was completely blocked by preloading with the Ca(2+) chelator BAPTA. In parallel experiments, BAPTA completely blocked the vasopressin-induced increase in P(f) without affecting adenosine 3',5'-cyclic monophosphate (cAMP) production. Previously, we demonstrated the lack of activation of the phosphoinositide-signaling pathway by vasopressin in IMCD, suggesting an inositol 1,4,5-trisphosphate-independent mechanism of Ca(2+) release. Evidence for expression of the type 1 ryanodine receptor (RyR1) in IMCD was obtained by immunofluorescence, immunoblotting, and reverse transcription-polymerase chain reaction. Ryanodine (100 microm), a ryanodine receptor antagonist, blocked the arginine vasopressin-mediated increase in P(f) and blocked vasopressin-stimulated redistribution of aquaporin-2 to the plasma membrane domain in primary cultures of IMCD cells, as assessed by immunofluorescence immunocytochemistry. Calmodulin inhibitors (W7 and trifluoperazine) blocked the P(f) response to vasopressin and the vasopressin-stimulated redistribution of aquaporin-2. The results suggest that Ca(2+) release from ryanodine-sensitive stores plays an essential role in vasopressin-mediated aquaporin-2 trafficking via a calmodulin-dependent mechanism.

ORE, a eukaryotic minimal essential osmotic response element. The aldose reductase gene in hyperosmotic stress

Organisms, almost universally, adapt to hyperosmotic stress through increased accumulation of organic osmolytes but the molecular mechanisms have only begun to be addressed. Among mammalian tissues, renal medullary cells are uniquely exposed to extreme hyperosmotic stress. Sorbitol, synthesized through aldose reductase, is a predominant osmolyte induced under hyperosmotic conditions in renal cells. Using a rabbit renal cell line, we originally demonstrated that hyperosmotic stress induces transcription of the aldose reductase gene. Recently, we cloned the rabbit aldose reductase gene, characterized its structure, and found the first evidence of an osmotic response region in a eukaryotic gene. Now, we have progressively subdivided this 3221-base pair (bp) region into discrete fragments in reporter gene constructs. Thereby, we have functionally defined the smallest sequence able to confer hyperosmotic response on a downstream gene independent of other putative cis-elements, that is, a minimal essential osmotic response element (ORE). The sequence of the ORE is CGGAAAATCAC(C) (bp -1105/-1094). A 17-bp fragment (-1108/-1092) containing the ORE used as a probe in electrophoretic mobility shift assays suggests hyperosmotic induction of a slowly migrating band. Isolation of trans-acting factor(s) and characterization of their interaction with the ORE should elucidate the basic mechanisms for regulation of gene expression by hyperosmotic stress.

Protection of renal inner medullary epithelial cells from apoptosis by hypertonic stress-induced p53 activation

Acute hypertonicity causes cell cycle delay and apoptosis in mouse renal inner medullary collecting duct cells (mIMCD3) and increases GADD45 expression. Because the tumor suppressor protein p53 may be involved in these effects, we have investigated the role of p53 in mIMCD3 response to hyperosmotic stress. Acute elevation of osmolality with NaCl addition from the control level of 320 mosmol/kg to 500-600 mosmol/kg greatly increased the levels of total and Ser(15)-phosphorylated p53 within 15 min. However, similar elevation of osmolality with urea did not increase p53 levels. Our studies indicate that induced p53 is transcriptionally active because NaCl addition to 500-600 mosmol/kg stimulated transcription of a luciferase reporter containing a p53 consensus element and appropriately altered mRNA levels of known transcriptional targets of p53, i.e. increased MDM-2 and decreased BCL-2 levels. Elevating NaCl further to 700-800 mosmol/kg rapidly killed most of the cells by apoptosis. At these higher NaCl concentrations, p53 levels were further increased although Ser(15) phosphorylation and transcriptional activity were significantly lower than levels at 500-600 mosmol/kg. At NaCl-induced 500 mosmol/kg, apoptosis was rare in the presence of control, nonspecific oligonucleotide but highly prevalent upon addition of p53 antisense oligonucleotide that substantially reduced p53 levels. We conclude that induction of active p53 in mIMCD3 cells by hypertonic stress contributes to cell survival.

Betaine transporter cDNA cloning and effect of osmolytes on its mRNA induction

Cells generally adapt to long-term hyperosmolality by accumulating compatible organic osmolytes, thereby helping to normalize both volume and intracellular inorganic ion concentration. When organic osmolytes are accumulated, as in renal inner medullary cells, it is the sum of their concentrations that is theoretically important. In effect, when one organic osmolyte rises, the others generally fall to maintain their sum approximately constant. The present study addresses the mechanism controlling betaine accumulation. Hypertonicity induces accumulation of betaine, sorbitol, inositol, and other organic osmolytes in PAP-HT25 cells, a line derived from rabbit renal papilla. Hypertonicity increases the betaine transporter expression in these cells. To obtain a specific probe for betaine transporter mRNA, we cloned from PAP-HT25 cells a cDNA that encodes the full protein. We then examined the effect of betaine, sorbitol, and inositol on betaine transporter mRNA abundance. Increased accumulation of any of these three organic osmolytes reduces betaine transporter mRNA. We previously observed similar results for aldose reductase, the enzyme responsible for osmotically regulated sorbitol accumulation. We conclude that the accumulation of organic osmolytes regulates betaine transporter gene expression. Because the aldose reductase gene is controlled in a similar fashion, we surmise that the two genes share a common signal for induction.

Distinct regulation of osmoprotective genes in yeast and mammals. Aldose reductase osmotic response element is induced independent of p38 and stress-activated protein kinase/Jun N-terminal kinase in rabbit kidney cells

In yeast glycerol-3-phosphate dehydrogenase 1 is essential for synthesis of the osmoprotectant glycerol and is osmotically regulated via the high osmolarity glycerol (HOG1) kinase pathway. Homologous protein kinases, p38, and stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK) are hyperosmotically activated in some mammalian cell lines and complement HOG1 in yeast. In the present study we asked whether p38 or SAPK/JNK signal synthesis of the osmoprotectant sorbitol in rabbit renal medullary cells (PAP-HT25), analogous to the glycerol system in yeast. Sorbitol synthesis is catalyzed by aldose reductase (AR). Hyperosmolality increases AR transcription through an osmotic response element (ORE) in the 5'-flanking region of the AR gene, resulting in elevated sorbitol. We tested if AR-ORE is targeted by p38 or SAPK/JNK pathways in PAP-HT25 cells. Hyperosmolality (adding 150 mM NaCl) strongly induces phosphorylation of p38 and of c-Jun, a specific target of SAPK/JNK. Transient lipofection of a dominant negative mutant of SAPK kinase, SEK1-AL, into PAP-HT25 cells specifically inhibits hyperosmotically induced c-Jun phosphorylation. Transient lipofection of a dominant negative p38 kinase mutant, MKK3-AL, into PAP-HT25 cells specifically suppresses hyperosmotic induction of p38 phosphorylation. We cotransfected either one of these mutants or their empty vector with an AR-ORE luciferase reporter construct and compared the hyperosmotically induced increase in luciferase activity with that in cells lipofected with only the AR-ORE luciferase construct. Hyperosmolality increased luciferase activity equally (5-7-fold) under all conditions. We conclude that hyperosmolality induces p38 and SAPK/JNK cascades in mammalian renal cells, analogous to inducing the HOG1 cascade in yeast. However, activation of p38 or SAPK/JNK pathways is not necessary for transcriptional regulation of AR through the ORE. This finding stands in contrast to the requirement for the HOG1 pathway for hyperosmotically induced activation of yeast GPD1.

Cloning, genomic organization, and osmotic response of the aldose reductase gene

Diverse organisms accumulate organic osmolytes to adapt to hyperosmotic stress. The molecular basis of eukaryotic gene osmoregulation remains obscure. Aldose reductase [AR; alditol:NAD(P)+ 1-oxidoreductase, EC 1.1.1.21], which catalyzes the conversion of glucose to sorbitol (an organic osmolyte), is induced in renal medullary cells under hyperosmotic conditions. Elevated extracellular NaCl increases AR mRNA transcription in PAP-HT25 cells, a cell line derived from the rabbit renal papilla. We have cloned and characterized the rabbit AR gene to determine how it is regulated by hyperosmolality. The length of the gene, not including 5' or 3' flanking regions, is approximately 14.7 kilobases (kb) organized into 10 exons and 9 introns. The transcription start site is 36 base pairs upstream of the initiator methionine codon. A 5-kb fragment containing approximately 3.5 kb of 5' flanking region was isolated. The 3.5-kb sequence was examined for basal promoter activity and hyperosmotic response in luciferase reporter gene constructs. A 235-base-pair fragment (base pairs -208 to +27) was able to drive the downstream reporter gene in transfected PAP-HT25 cells under isoosmotic conditions (300 mosmol/kg of H2O). When this fragment plus the remaining upstream sequence (from approximately base pair -3429 to base pair +27) was used, cells in hyperosmotic medium (500 mosmol/kg of H2O) showed about 40-fold induction of luciferase expression compared with cells in isoosmotic medium. The upstream fragment (from approximately base pair -3429 to base pair -192) also conferred osmotic response to a heterologous promoter (B19). This finding evidences putative osmotic response element(s) (OREs) within a specific DNA fragment in a eukaryotic genome. Identification and characterization of OREs within this fragment and their associated trans-acting factors should reveal the molecular mechanisms of gene regulation in osmotic stress.

Functional consensus for mammalian osmotic response elements

The molecular mechanisms underlying adaptation to hyperosmotic stress through the accumulation of organic osmolytes are largely unknown. Yet, among organisms, this is an almost universal phenomenon. In mammals, the cells of the renal medulla are uniquely exposed to high and variable salt concentrations; in response, renal cells accumulate the osmolyte sorbitol through increased transcription of the aldose reductase (AR) gene. In cloning the rabbit AR gene, we found the first evidence of an osmotic response region in a eukaryotic gene. More recently, we functionally defined a minimal essential osmotic response element (ORE) having the sequence CGGAAAATCAC(C) (bp -1105 to -1094). In the present study, we systematically replaced each base with every other possible nucleotide and tested the resulting sequences individually in reporter gene constructs. Additionally, we categorized hyperosmotic response by electrophoretic mobility shift assays of a 17-bp sequence (-1108 to -1092) containing the native ORE as a probe against which the test constructs would compete for binding. In this manner, binding activity was assessed for the full range of osmotic responses obtained. Thus we have arrived at a functional consensus for the mammalian ORE, NGGAAAWDHMC(N). This finding should accelerate the discovery of genes previously unrecognized as being osmotically regulated.

Induction of gene expression by heat shock versus osmotic stress

Elevated temperature rapidly increases expression of genes for heat shock proteins (HSP), including HSP-70. The response is presumably triggered by denaturation of cell proteins and helps in their renaturation. Hypertonicity may also denature proteins, but the protective response, which is accumulation of compatible organic osmolytes [including betaine and inositol in Madin-Darby canine kidney (MDCK) cells], apparently differs and is slow. Recently, hypertonicity was found also to increase expression of HSP-70 in MDCK cells, a response proposed to provide protection until organic osmolytes can accumulate. Our purpose was to examine whether 1) a gene involved in accumulation of organic osmolytes also responds to heat stress and 2) whether accumulation of organic osmolytes affects expression of HSP-70. We find that 1) the betaine transporter mRNA, which is greatly increased by hypertonicity (515 vs. 315 mosmol), is unaffected by high temperature (42 degrees C vs. 37 degrees C); 2) hypertonicity-induced increases in HSP-70 and betaine transporter mRNA are much greater when the medium (and cell) contain no betaine and no inositol than when high concentrations of these are present; and 3) high betaine greatly inhibits the increase in HSP-70 mRNA at high temperature. We conclude the following. 1) Although heat shock and betaine transporter genes both respond to hypertonicity, the betaine transporter is not a HSP. 2) Accumulation of organic osmolytes attenuates the HSP-70 response to hypertonicity, as it might if the HSP-70 expression were a temporizing response. 3) Betaine inhibits HSP-70 response to elevated temperature, presumably by its known effect of stabilizing proteins.

Estrogens exert a rapid apoptotic action in anterior pituitary cells

It is now accepted that estrogens not only stimulate lactotrope proliferation but also sensitize anterior pituitary cells to proapoptotic stimuli. In addition to their classical mechanism of action through binding to intracellular estrogen receptors (ERs), there is increasing evidence that estrogens exert rapid actions mediated by cell membrane-localized ERs (mERs). In the present study, we examined the involvement of membrane-initiated steroid signaling in the proapoptotic action of estradiol in primary cultures of anterior pituitary cells from ovariectomized rats by using estren, a synthetic estrogen with no effect on classical transcription and a cell-impermeable 17beta-estradiol conjugate (E2-BSA). Both compounds induced cell death of anterior pituitary cells after 60 min of incubation as assessed by flow cytometry and the [3-(4,5-dimethylthiazol-2-yl)]-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Estren, E2, and E2-BSA induced apoptosis of lactotropes and somatotropes as evaluated by the deoxynucleotidyltransferase-mediated dUTP nick end-labeling assay and immunodetection of prolactin (PRL) and growth hormone (GH). The proapoptotic effect of E2-BSA was abrogated by ICI-182,780, an antagonist of ERs. The expression of membrane-associated ERalpha was observed in PRL- and GH-bearing cells. Our results indicate that estradiol is able to exert a rapid apoptotic action in anterior pituitary cells, especially lactotropes and somatotropes, by a mechanism triggered by mERs. This mechanism could be involved in anterior pituitary cell turnover.

Delayed puberty in males with chronic renal failure

The effects of chronic renal failure on the pituitary-testicular axis of 31 males, aged 11.7 to 20.0 yr (mean, 16.0 yr) were studied. Nine patients not on hemodialysis (group I) had serum creatinines between 2.5 and 8.0 mg/dl, 10 patients were on hemodialysis (group II) and 12 patients had received a renal transplant (group III). The Tanner stage of pubertal development was delayed relative to chronologic age. Testosterone (T), delta 4-androstenedione (delta 4), and urinary 17-keto steroids were normal when related to pubertal stage in groups I and II; and dehydroepiandrosterone (DHEA) and DHEA sulfate (DS) were in the low normal range. In group III, adrenal androgens (delta 4, DHEA, DS) were decreased as a consequence of prednisone therapy whereas T was normal. Luteinizing hormone levels were normal in all. Follicle-stimulating hormone levels were normal in all. Follicle-stimulating hormone (FSH) was significantly increased in groups I and II. In group III, FSH was normal in 6 of 9 patients with serum creatinine concentrations < 2 mg/dl. FSH levels were uniformly elevated in Tanner I-V patients with creatinines > 2 mg/dl. The data shows that FSH is elevated in patients with chronic renal failure even in prepuberty and early adolescence. This may reflect damage to germinal epithelium prior to the advent of spermatogenesis, whereas Leydig cell function appears to remain intact.

Estrogens sensitize anterior pituitary gland to apoptosis

Tissue homeostasis results from a balance between cell proliferation and cell death by apoptosis. Estradiol affects proliferation as well as apoptosis in hormone-dependent tissues. In the present study, we investigated the apoptotic response of the anterior pituitary gland to lipopolysaccharide (LPS) in cycling female rats, and the influence of estradiol in this response in ovariectomized (OVX) rats. The OVX rats were chronically estrogenized with implanted Silastic capsules containing 1 mg of 17beta-estradiol (E2). Cycling or OVX and E2-treated rats were injected with LPS (250 microg/rat ip). Apoptosis was determined by the terminal deoxynucleotidyl-mediated dUTP nick-end labeling (TUNEL) method in sections of the anterior pituitary gland and spleen. Chronic estrogenization induced apoptosis in the anterior pituitary gland. Acute endotoxemia triggered apoptosis of cells in the anterior pituitary gland of E2-treated rats but not of OVX rats. No differences were observed in the apoptotic response to LPS in spleen between OVX and E2-treated rats. The apoptotic response of the anterior pituitary to LPS was variable along the estrous cycle, being higher at proestrus than at estrus or diestrus I. Approximately 75% of the apoptotic cells were identified as lactotropes by immunofluorescence. In conclusion, our results indicate that estradiol induces apoptosis and enables the proapoptotic action of LPS in the anterior pituitary gland. Also, our study suggests that estrogens may be involved in anterior pituitary cell renewal during the estrous cycle, sensitizing lactotropes to proapoptotic stimuli.

Measurement precision of a portable instrument to assess vibrotactile perception threshold

The objective of the present study was to evaluate the reliability of a modified version of the commercially available Biothesiometer, and to examine vibrotactile perception thresholds with respect to age and gender. A standardized protocol for measuring vibrotactile perception threshold was administered to 80 subjects, once a week over 4 weeks. Inter-session variability was stable (analysis of variance for repeated measures; P greater than 0.05) and correlations were high (Pearson's: 0.87 less than or equal to r less than or equal to 0.90; P less than or equal to 0.001). For sites on both hands and feet, there was a significant increase with age (0.19 less than or equal to r2 less than or equal to 0.52; P less than or equal to 0.001). Five factor analysis of variance model showed that vibrotactile perception threshold was significantly different with stimulus site, age category and gender; no differences were observed with alcohol consumption or smoking status. The findings indicate that the measurements from this device are highly reproducible and sensitive to expected threshold differences with age and gender. The authors attribute this to technical improvements of the original apparatus, rigid adherence to test protocol and maintenance of standard conditions. This type of instrument would be useful in assessing vibrotactile perception loss in occupational health studies.

CD9 antigen mRNA is induced by hypertonicity in two renal epithelial cell lines

In diverse organisms, cells adapt to hyperosmotic stress by accumulating organic osmolytes. Mammalian renal medullary cells are routinely under osmotic stress. Two renal cell lines, Madin-Darby canine kidney (MDCK) and PAP-HT25, have been widely used to study mammalian osmotic regulation. In these epithelial cells, extracellular hypertonicity induces gene transcription of proteins directly involved in the metabolism and transport of organic osmolytes. This induction is relatively specific and not part of a generalized stress response. Little is known about the signal transduction pathway between cellular detection of extracellular osmolality and increased specific gene transcription. Here, using differential mRNA display polymerase chain reaction on MDCK cells in isotonic vs. hypertonic medium, we identify a cDNA product corresponding to CD9 antigen mRNA. CD9 antigen is a cell surface glycoprotein originally found in cells of the immune system. Although CD9 antigen has been structurally characterized, its function is unclear. We further demonstrate that CD9 antigen mRNA is present in MDCK and PAP-HT25 cells and that its mRNA abundance is induced by extracellular hypertonicity, but not by heat stress. Also, we show that accumulation of organic osmolytes markedly attenuates the CD9 mRNA induction, as only recently demonstrated with genes involved in the hyperosmotic stress response. This suggests a role for CD9 antigen in this response.

Renal transplantation in patients with classical haemolytic-uraemic syndrome

Eighteen records from children with renal transplants (RT) and classical haemolytic-uraemic syndrome (HUS) were reviewed. The mean oliguric period was 17.9 +/- 7.5 days; the interval between acute phase and end-stage renal disease (ESRD) was 9.3 +/- 5.2 years. HUS was the most frequent cause of renal transplantation (23.4%). There were no significant differences between patients with HUS and controls (children with RT but without HUS), regarding renal function, frequency of rejections, renal survival (HUS 65%, controls 57%) or patient survival (94.4% and 96.6%, respectively) after 9 years. None had clinical or histopathological evidence of HUS recurrence in the allograft. Of all children with living-related donors (LRD), renal survival after 3 years was longer for those who received cyclosporin A (CSA) (HUS and controls 86%) than for those who did not receive it (HUS 50%, controls 53%). Classical HUS is a frequent cause of ESRD in Argentina. The duration of the acute oliguric period is a good predictor of the likelihood of progression to chronicity. In the classical form of HUS there is no recurrence in the allograft. CSA and LRD can be used without risk in renal transplantation of children with classical HUS.

In vivo osmoregulation of aldose reductase mRNA, protein, and sorbitol in renal medulla

Sorbitol accumulates in renal medullary cells by synthesis from glucose in a reaction catalyzed by aldose reductase. Medullary sodium and urea are high and vary with urinary concentration. Sorbitol varies similarly, consistent with its role as a compatible intracellular organic osmolyte. We measured renal medullary sodium, urea, sorbitol, aldose reductase (protein and activity), and aldose reductase mRNA in rats treated to change medullary sodium and urea. In untreated Brattleboro rats all measurements were low and increased after 7 days of treatment with arginine vasopressin. In contrast, when normal rats were water deprived for 3 days, urea increased out of proportion to sodium, and sorbitol, aldose reductase, and aldose reductase mRNA were unchanged. After 2 h of diuresis, normal rats had lower medullary sodium and urea and reduced mRNA and sorbitol; however aldose reductase did not change. These data are consistent with previous results from cultured cells in which altered extracellular sodium, but not urea, leads to rapid changes in aldose reductase mRNA and slow changes (days) in aldose reductase. In addition, acute decreases in extracellular sodium increase leakage of sorbitol from cells. We also confirm previous results showing medullary glycerophosphorylcholine correlates best with urea, whereas the sum of all compatible osmolytes correlates best with sodium.

Participation of membrane progesterone receptor α in the inhibitory effect of progesterone on prolactin secretion

The membrane progesterone receptors (mPRα, mPRβ, mPRγ, mPRδ and mPRε) are known to mediate rapid nongenomic progesterone functions in different cell types. However, the functions of these receptors in the pituitary have not been reported to date. In the present study, we show that the expression of mPRα was the highest among the mPRs in the rat anterior pituitary gland. Immunostaining of mPRα was detected in somatotrophs, gonadotrophs and lactotrophs. Interestingly, 63% of mPRα-positive cells within the pituitary were lactotrophs, suggesting that mPRα is involved in controlling prolactin (PRL) secretion in the pituitary. To test this hypothesis, rat pituitaries were incubated (1 hour) with either progesterone (P4) or the mPRα-specific agonist Org OD 02-0. PRL secretion was then measured by radioimmunoassay. The results of this experiment revealed that both P4 and Org OD 02-0 decreased PRL secretion. Moreover, the results from the GH3 cell line (CCL-82.1) showed that P4 and Org OD 02-0 inhibited PRL release, although the nuclear PR agonist R5020 was ineffective. Our investigation of the cellular mechanisms behind mPRα activity indicated that both P4 and Org OD 02-0 decreased cAMP accumulation, whereas R5020 was ineffective. In addition, the Org OD 02-0-effect on PRL release was blocked by pretreatment with pertussis toxin, an inhibitor of Go/Gi proteins. Because transforming growth factor (TGF)β1 is a potent inhibitor of PRL secretion in lactotrophs, we lastly evaluated whether TGFβ1 was activated by progesterone and whether this effect was mediated by mPRα. Our results showed that P4 and Org OD 02-0, but not R5020, increased active TGFβ1 levels. This effect was not observed when cells were transfected with mPRα-small interfering RNA. Taken together, these data provide new evidence suggesting that mPRα mediates the progesterone inhibitory effect on PRL secretion through both decreases in cAMP levels and activation of TGFβ1 in the lactotroph population.

Measurement precision of an olfactory perception threshold test for use in field studies

Changes in olfactory function have been associated with workplace exposure to a variety of substances. In the workplace, smell can be particularly important, since it is commonly used to detect potentially hazardous situations or as an indicator of mask cartridge breakthrough. Sensitive quantitative measures of olfactory loss would be useful in epidemiological studies and workplace surveillance. The objective of the present study was to determine the reproducibility of an olfactory perception threshold test and variations with age, gender, and smoking status. The test was a standard olfactory kit (Olfactolab No. 11), including 18 serial dilutions of PM-carbinol, with an equal number of blanks. The forced choice method was used, with both tester and subject blinded as to which bottle contained the odorant. Olfactory perception threshold was recorded when the subject identified the same dilution three times. To assess reproducibility, testing was repeated four times over a period of 4 weeks, on the same weekday and the same time of day. Subjects (n = 63) ranged in age from 20 to 60 years (mean age: 39.7 +/- 12.5 years), 47.6% were women, 29.5% currently smoked, and 27.9% were former smokers. Results showed no inter-week differences in olfactory perception threshold (Analysis of variance for repeated measures: F = 0.59; p much greater than 0.05). Inter-class correlation for assessment of agreement of continuous variables was 0.76. Inter-week concordance of hyposmia showed fair to good agreement (0.55 greater than or equal to kappa less than or equal to 0.66). Three-way analysis of variance (ANOVA) revealed significant differences with respect to age category (F = 7.36; p less than 0.001) and current smoking status (F = 4.54; p less than 0.05), but not for gender (F = 2.32; p greater than 0.05). The multiple regression model with age and smoking as independent variables was highly significant (F = 13.03; p less than 0.001), explaining 28% of the variance; olfactory threshold increased 0.47 ds/year (t = 4.01; p less than 0.001) and 0.27 ds/cigarettes/day (t = 2.46; p less than 0.05). The findings of this study indicate that this test is reproducible and sensitive to expected changes with age and smoking status. It corresponds well to criteria for testing in the field and should be considered for studies characterizing olfactory functions and sensory loss among working populations.

Integrated coastal zone management perspectives to ensure the sustainability of coral reefs in New Caledonia

Based on a pluridisciplinary research programme on New Caledonia's lagoon (2004-2008), this paper addresses economic, ecological and political issues in order to implement integrated coastal zone management (ICZM) in this French Pacific territory. The nickel mining industry constitutes the core of the re-balancing economic and social strategy between the Northern and Southern provinces. But major impacts on the coastal environment of metal-processing plants, harbours, and decades of mine exploitation have released a controversy. A short diachronic analysis suggests that such environmental concerns prompted the emergence of collective actions to among civil society, customary and institutional stakeholders. The inscription of New Caledonia lagoon and reef areas in the UNESCO World Heritage List in 2008 would be both an outcome and a catalyst of this on-going process. Looking beyond the reefs towards the mainland and watersheds for the construction of local socio-ecological systems, we assume that the current stakes could result in the initiation of ICZM in New Caledonia.

Evidence of hypothalamic-pituitary thyroid abnormalities in children with end-stage renal disease

Patients with end-stage renal disease may have abnormalities of growth and of gonadal and thyroid hormones, so we attempted to determine the mechanisms that may be involved in the altered thyroid function. We evaluated serum thyroid hormone levels, their changes immediately after hemodialysis, the serum thyrotropin (thyroid-stimulating hormone (TSH) response to thyrotropin releasing hormone, and the circadian pattern of serum TSH in nine children with end-stage renal disease who were between 7 1/2 years and 17 years 1 month of age. Seven patients had been receiving hemodialysis for a median of 3.3 years; the other two were receiving continuous ambulatory peritoneal dialysis. Four patients had low serum total thyroxine (T4) values, and all nine had low free T4 values. Mean concentrations of total T4, free T4, and total triiodothyronine (T3), which were significantly less than normal before hemodialysis, returned to normal levels immediately after dialysis. Postdialysis thyroid hormone increases did not correlate with the decrease in weight or the increase in hematocrit observed immediately after dialysis. All but one patient had basal TSH levels within the normal range. Three patients had a deficient TSH response to thyrotropin releasing hormone, and the TSH response was prolonged in all of them. The mean (+/- SD) nocturnal TSH surge was 50 +/- 68%. Five of the eight patients studied had a nocturnal TSH surge below the normal range (95% confidence limits 47% to 300%). Serum free T4 values correlated with the TSH nocturnal surge (r, 0.73; p less than 0.05). Our findings support the hypothesis that some patients with end-stage renal disease have central hypothyroidism.

Complete analysis of the trace elements of the kidney

The distribution of trace elements in kidney cortex and medulla and in their subcellular fractions was studied by inductively coupled plasma mass spectrometry (ICP-MS). This technology allows the analysis of almost all the elements of the periodic table, along with their isotopes, in the same experiment. Acid digestion of the tissue (samples) was required before ICP-MS elemental analysis. Mineralization in 8 N nitric acid for 2 min in a Parr microwave acid digestion bomb, inside a regular microwave oven working at medium power, gave good sensitivity and reproducible results. Trace element determinations could be precisely performed, despite the presence of a considerable amount of organic matter. Cortex/plasma and medulla/plasma inorganic ratios were taken as indicators of the inorganic bioaccumulation. The highest enrichment factors of elements found in the cortex were Mn greater than Co greater than Tl greater than Zn greater than Rb greater than Mo greater than Cu and the highest element enrichments of the medulla were Tl greater than Mn greater than Co greater than Rb greater than Zn greater than Bi greater than Mo greater than Ni greater than Cu. Subcellular fragmentation of the kidney cortex and medulla indicated that the majority of the trace elements was located in the cytosolic fraction. The membrane fraction of the medulla contained significant amounts of Hg and Al: 120.7 and 32.0 mg/g protein, respectively. Cu and Zn were the most abundant trace elements found in the brush border membrane from the cortex: 120.7 and 68.2 mg/g protein, respectively. These quantities are largely in excess of what is bound, for example, to alkaline phosphatase.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of nuclear factor-kappa B sensitises anterior pituitary cells to tumour necrosis factor-α- and lipopolysaccharide-induced apoptosis

Nuclear factor-kappa B (NF-κB), an important pro-inflammatory factor, is a crucial regulator of cell survival. Both lipopolysaccharide (LPS) and tumour necrosis factor (TNF)-α activate NF-κB signalling. Oestrogens were shown to suppress NF-κB activation. Oestrogens exert a sensitising action to pro-apoptotic stimuli such as LPS and TNF-α in anterior pituitary cells. In the present study, we show by western blotting that 17β-oestradiol (E(2)) decreases TNF-α-induced NF-κB/p65 and p50 nuclear translocation in primary cultures of anterior pituitary cells from ovariectomised (OVX) rats. Also, the in vivo administration of E(2) decreases LPS-induced NF-κB/p65 and p50 nuclear translocation. To investigate whether the inhibition of NF-κB pathway sensitises anterior pituitary cells to pro-apoptotic stimuli, we used an inhibitor of NF-κB activity, BAY 11-7082 (BAY). BAY, at a concentration that fails to induce apoptosis, has permissive action on TNF-α-induced apoptosis of lactotrophs and somatotrophs from OVX rats, as assessed by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL). Pharmacological inhibition of NF-κB signalling enhances E(2)-sensitising effect to TNF-α-induced apoptosis in lactotrophs but not in somatotrophs. In vivo administration of BAY allowed LPS-induced apoptosis in anterior pituitary cells from OVX rats (determined by fluorescence activated cell sorting). Furthermore, LPS-induced expression of Bcl-xL in pituitaries of OVX rats is decreased by E(2) administration. Our results show that inhibition of the NF-κB signalling pathway sensitises anterior pituitary cells to the pro-apoptotic action of LPS and TNF-α. Because E(2) inhibits LPS- and TNF-α-activated NF-κB nuclear translocation, the present study suggests that E(2) sensitises anterior pituitary cells to TNF-α- and LPS-induced apoptosis by inhibiting NF-κB activity.

Geographical aspects of informal reef fishery systems in New Caledonia

The coral reefs in New Caledonia have long been used by the local population for subsistence as well as commercial and recreational purposes. The impact of informal fisheries on reef ecosystems illustrated the idiosyncrasies of New Caledonian fisheries in the southwest Pacific. This paper compared informal fishery systems on the southwest coast (close to the capital and economic center of the country) and the northwest coast (where an industrial mining complex has been under development) of New Caledonia to analyze their spatial structure and characteristics. Four geosystems were defined. These depended on the natural, social and economical environments as well as management strategies. The way of life of the fishers proved to be a major factor in how the informal fishery systems were structured. Our observations suggested that ongoing socio-economic changes in New Caledonia have shaped informal fishing activities since the 1900s. The findings from this study validate the suitability of spatial approaches to coral reef fisheries and provide local stakeholders with original management clues for marine resources sustainability.