The heritability of general cognitive ability increases linearly from childhood to young adulthood.

Although common sense suggests that environmental influences increasingly account for individual differences in behavior as experiences accumulate during the course of life, this hypothesis has not previously been tested, in part because of the large sample sizes needed for an adequately powered analysis. Here we show for general cognitive ability that, to the contrary, genetic influence increases with age. The heritability of general cognitive ability increases significantly and linearly from 41% in childhood (9 years) to 55% in adolescence (12 years) and to 66% in young adulthood (17 years) in a sample of 11 000 pairs of twins from four countries, a larger sample than all previous studies combined. In addition to its far-reaching implications for neuroscience and molecular genetics, this finding suggests new ways of thinking about the interface between nature and nurture during the school years. Why, despite life's 'slings and arrows of outrageous fortune', do genetically driven differences increasingly account for differences in general cognitive ability? We suggest that the answer lies with genotype-environment correlation: as children grow up, they increasingly select, modify and even create their own experiences in part based on their genetic propensities.

Differential genetic etiology of reading difficulties as a function of IQ: an update.

In order to test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 308 pairs of identical (monozygotic, MZ) twins and 440 pairs of fraternal (dizygotic, DZ) twins (254 same-sex and 186 opposite-sex) in which at least one member of each pair was classified as reading-disabled were subjected to multiple regression analysis (DeFries and Fulker, Behav Genet 15:467-473, 1985; Acta Genet Med Gemellol 37:205-216, 1988). In the total sample, heritability of the group deficit in reading performance (h(g)(2)) was .61 (±.06). However, results of fitting an extended regression model to reading performance and IQ data suggested that the genetic etiology of reading disability differs as a linear function of IQ (p ≤ .04). When the basic regression model was fitted separately to data from twin pairs with Wechsler (Examiner's manual: Wechsler intelligence scale for children-revised, 1974; Examiner's manual: Wechsler adult intelligence scale-revised, 1981) Full Scale IQ scores in the upper and lower 25% of the sample, resulting estimates of h(g)(2) were .75 (±.12) and .50 (±.10), respectively (p ≤ .045). These results suggest that reading difficulties in children with a higher IQ are due substantially to genetic influences and may require intensive remediation efforts.

Demonstration of 2-hydroxybenzoylglycine as a drug binding inhibitor in newborn infants.

Newborn infants have drug binding defects that share similarities to those of uremic subjects. Since 2-hydroxybenzoylglycine has been chemically defined to be a major drug binding inhibitor in uremia, a search for the presence of a similar compound in the sera of newborn infants was made. An organic substance that has the characteristics of 2-hydroxybenzoylglycine as supported by the retardation factor values on thin-layer chromatograms, retention times of high performance liquid chromatograms, fluorescence emission spectra, and mass spectrum has been demonstrated to be present in the majority of the neonatal sera studied. A strong positive correlation between the levels of the binding inhibitor and the extent of binding defects for nafcillin has been observed. The substance could effectively reduce the total bilirubin concentration when added to the cord sera specimens. It is concluded that 2-hydroxybenzoylglycine plays an important role in drug binding defects observed in the newborn, and the inhibitor may also play a part in the precipitation of bilirubin-induced neurotoxicity in neonates when the substance is abnormally elevated.

Spontaneous regression of pulmonary metastases demonstrated by CT.

Two cases of disappearing or spontaneous regression of pulmonary metastases on CT are presented. In both cases, cytological proof was obtained by radiologically guided fine needle aspiration. The lesions subsequently regressed on follow-up CT studies without recognized systemic treatment.

Fatal complication of an expandable metallic bronchial stent.

A case of massive fatal haemoptysis secondary to erosion of a Gianturco expandable wire bronchial stent is described. The stent had been inserted for a benign bronchial stenosis. CT demonstrated erosion of the stent through the oesophagus and a false aneurysm of the descending thoracic aorta. The CT and plain radiographic appearances are presented. The potential for progressive migration and local damage should limit the use of this type of stent in benign bronchial stenoses.

Gender differences in cognitive abilities of reading-disabled twins.

Gender differences were assessed in three research-identified samples of children who were members of twin pairs: (1) 120 male and 124 female probands from same-sex identical and fraternal twin pairs in which at least one member of each pair is reading disabled; (2) a comparison sample of 148 males and 161 females from same-sex twin pairs with no history of reading problems; and (3) 34 pairs of opposite-sex fraternal twin pairs in which at least one member of each pair is reading disabled. Results of multivariate analyses of variance of psychometric test data from the two samples of same-sex twin pairs, in which the male and female subjects were reared in different homes, suggest that profiles of gender differences are similar in reading-disabled and control children. Moreover, this pattern of gender differences also tended to occur in opposite-sex twin pairs, who shared prenatal, as well as early postnatal, environmental influences. In general, reading-disabled males obtained higher average scores than affected females on Wechsler (1974, 1981) Verbal and Performance IQ, but lower scores on Reading Recognition and Spelling subtests of the Peabody Individual Achievement Test (Dunn and Markwardt 1970). With regard to the Wechsler subtests, reading-disabled males achieved higher average scores on Information, Picture Completion, Block Design, and Object Assembly, but lower scores on Coding. Although significant and relatively consistent gender differences in cognitive measures were found in three samples included in this study, these differences account for only a small portion of the observed variance.

Cognitive abilities of children at 7 and 12 years of age in the Colorado adoption project.

To test the hypothesis that adopted children are at an elevated risk for learning disabilities, the achievement and WISC-R test scores of a nonclinical sample of adopted and nonadopted (control) children were compared at 7 years of age (n = 108 adopted males, 91 adopted females, 116 control males, 100 control females) and 12 years of age (n = 69 adopted males, 61 adopted females, 56 control males, 44 control females). Although the average Verbal IQ of the adopted children was significantly lower than that of the nonadopted children at both ages, these differences accounted for only about 2% to 4% of the variance. When scores on the individual subtests of the WISC-R were compared, the group difference was significant only for Similarities at age 7, and for Comprehension at age 12. Moreover, with regard to the achievement tests, the proportion of adopted children who scored more than 1.5 standard deviations below expected, based on IQ, was not significantly greater than that of controls. Also, the proportions of adopted and control children placed in special education classes were not significantly different. Thus, the results of this study provide little or no evidence for an increased risk of learning disabilities in "easily placed" adopted children.

Differential genetic etiology of reading disability as a function of IQ.

To test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 223 pairs of identical twins and 169 pairs of same-gender fraternal twins in which at least one member of each pair was classified with reading disability were subjected to multiple regression analysis (DeFries & Fulker, 1985, 1988). In the total sample, heritability of the group deficit in reading performance (h(g)2) was .58 (+/- .08). However, when the basic regression model was fitted separately to data from twin pairs with average Wechsler (1974, 1981) full scale IQ scores below 100 or 100 and above, resulting estimates of h(g)2 were .43 and .72, respectively, a significant difference (p < or = .03, one-tailed). The results of fitting extended regression models to reading performance and continuous IQ data provide evidence that the genetic etiology of reading disability differs as a linear function of IQ (p < or = .007, one-tailed). These results suggest that IQ is relevant for the diagnosis of reading disability and that environmental influences may be more salient as a cause of reading difficulties in children with lower IQ scores.

Genetic and environmental influences on age at sexual initiation in the Colorado Adoption Project.

Whereas the majority of research on adolescent sexual initiation has focused solely on environmental factors, the present study used behavioral genetic analyses to investigate the relative contributions of genetic and environmental influences. Structural equation models were fitted to data from adoptive and non-adoptive sibling pairs (231 biologically related pairs and 169 unrelated pairs) from the Colorado Adoption Project. Information from censored individuals who had not yet experienced sexual initiation was maximized by adapting the twin survival analysis method of Pickles et al. (Behav Genet 24(5):457-468, 1994) to accommodate adoptive and non-adoptive siblings. Point estimates of variance components from an ACE model, including additive genetic (A), shared environmental (C), and non-shared environmental (E) influences were 28%, 24%, and 48%, respectively. Despite the lower point estimate for shared environmental effects than additive genetic effects, a CE model provided the best fit to the data. However, because adoptive siblings provide a direct estimate of shared environmental influences there is greater power to detect shared environmental effects in adoption designs. Evidence for genetic influences from our data were somewhat lower than those obtained in previous twin studies, possibly reflecting a return to more socially conservative sexual attitudes, changing sexual behaviors, or ambiguities in the wording of questions commonly used in research on adolescent sexuality.

In vitro displacement of bilirubin by antibiotics and 2-hydroxybenzoylglycine in newborns.

Hyperbilirubinemia is frequently observed in neonates, and serious neurological complications such as kernicterus can be precipitated when the concentration of unconjugated bilirubin is abnormally increased. The administration of drugs which bind to albumin and compete with bilirubin can increase the possibility of such a complication. To test the bilirubin-displacing activity of pharmacological agents that are used with newborns, 52 antimicrobial agents were investigated in vitro. A glycine conjugate of salicylate, 2-hydroxybenzoylglycine, which is known to be present at elevated levels in newborns and has a potent bilirubin-displacing property, was used as a positive control agent. Pooled cord serum was used as a source of hyperbilirubinemic serum. A centrifugal ultrafiltration method with semipermeable cones was employed to determine the effects of potential bilirubin-displacing agents on the levels of total bilirubin. 2-Hydroxybenzoylglycine was demonstrated to be the most potent bilirubin-displacing agent. Antibiotics could be classified into four groups: high-level displacers (sulfisoxazole, sulfamethoxazole, dicloxacillin, cefoperazone, and ceftriaxone), intermediate-level displacers (moxalactam, nafcillin, and 14 others), low-level displacers (aztreonam, carbenicillin, and 11 others), and nondisplacers (mezlocillin, cefuroxime, kanamycin, and 15 others). It is concluded that the ultrafiltration method is a rapid and readily reproducible for the determination of bilirubin displacement and that antibiotics with a tendency to displace bilirubin should be avoided in jaundiced newborns whenever appropriate alternatives are available.

H+-and K+-dependence of Ca2+ uptake in lung lamellar bodies.

Lung lamellar bodies maintain an acidic interior by an energy-dependent process. The acidic pH may affect the packaging of surfactant phospholipids, processing of surfactant proteins, or surfactant protein A-dependent lipid aggregation. The electron-probe microanalysis of lamellar body elemental composition has previously suggested that lamellar bodies contain high levels of calcium some of which may be in ionic form. In this study, we investigated the Ca2+ uptake characteristics in isolated lung lamellar bodies. The uptake of Ca2+ was measured by monitoring changes in the fluorescence of Fluo-3, a Ca2+ indicator dye. The uptake of Ca2+ in lamellar bodies was ATP-dependent and increased with increasing concentrations of Ca2+. At 100 nM Ca2+, the uptake was almost completely inhibited by bafilomycin A1, a selective inhibitor of vacuolar type H+-ATPase, or by NH4Cl, which raises the lamellar body pH, suggesting that the pH gradient regulates the uptake. The uptake of Ca2+ increased as the Ca2+ concentration was increased, but the relative contribution of bafilomycin A1-sensitive uptake decreased. At 700 nM, it comprised only 20% of the total uptake. These results suggest the presence of additional mechanism(s) for uptake at higher Ca2+ concentrations. At 700 nm Ca2+, the rate and extent of uptake were lower in the absence of K+ than in the presence of K+. The inhibitors of Ca2+-activated K+-channels, tetraethylammonium, Penitrem A, and 4-aminopyridine, also inhibited the K+-dependent Ca2+ uptake at 700 nM Ca2+. Thus the uptake of Ca2+ in isolated lung lamellar bodies appears to be regulated by two mechanisms, (i) the H+-gradient and (ii) the K+ transport across the lamellar body membrane. We speculate that lamellar bodies accumulate Ca2+ and contribute to regulation of cytosolic Ca2+ in type II cells under resting and stimulated conditions.

Listeria monocytogenes phospholipase C-dependent calcium signaling modulates bacterial entry into J774 macrophage-like cells.

Listeria monocytogenes secretes several proteins that have been shown to contribute to virulence. Among these is listeriolysin O (LLO), a pore-forming hemolysin that is absolutely required for virulence. Two other virulence factors are phospholipases: a phosphatidylinositol-specific phospholipase C (PI-PLC [plcA]) and a broad-range PLC (plcB). Although mutations in plcA or plcB resulted in small increases in mouse 50% lethal dose (LD50), deletions in both genes resulted in a 500-fold increase in LD50. We have examined the role of these secreted proteins in host intracellular signaling in the J774 macrophage-like cell line. Measurements of cytosolic free calcium ([Ca2+]i) have revealed a rapid spike upon exposure of these cells to wild-type L. monocytogenes. This is followed by a second peak at 5 min and a third prolonged peak with a maximal [Ca2+]i of 800 to 1,000 nM. The pattern of calcium changes was greatly altered by deletion of any of the three virulence factors. An LLO mutant produced none of these elevations in [Ca2+]i; however, a transient elevation was observed whenever these bacteria entered the cell. A PI-PLC mutant produced a diminished single elevation in [Ca2+]i at 15 to 30 min. A broad-range PLC mutant produced only the first calcium spike. Studies with inhibitors suggested that the first elevation arises from influx of calcium from the extracellular medium through plasma membrane channels and that the second and third elevations come from release of Ca2+ from intracellular stores. We observed that internalization of wild-type bacteria and the broad-range PLC mutant was delayed for 5 to 10 min, but the LLO and PI-PLC mutants were internalized rapidly upon infection. Inhibitors that affected calcium signaling changed the kinetics of association of wild-type bacteria with J774 cells, the kinetics of entry, and the efficiency of escape from the primary phagosome.

Ionic regulation of proton chemical (pH) and electrical gradients in lung lamellar bodies.

This study investigated the pH (chemical) and electrical gradients in lamellar bodies, the acidic surfactant-secreting organelles of lung epithelial type II cells, by following the uptake of a weak fluorescent base, quinacrine, and a membrane potential-sensitive dye, bis-(3-phenyl-5-oxoisoxazol-4-yl)pentamethine oxonol (oxonol V). In isolated lung lamellar bodies, the ATP-dependent uptake of both agents could be inhibited by bafilomycin A1, a reportedly specific inhibitor of vacuolar-type H(+)-ATPase (V-ATPase) and could be dissipated by a protonophore, carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone, suggesting that the V-ATPase generates an electropositive interior. A closely linked uptake of Cl- neutralizes the positive electrical potential and increases the proton pump activity. The uptake of quinacrine, but not oxonol V, was decreased by Na+. This effect of Na+ could be prevented by dimethylamiloride, suggesting the presence of electroneutral Na+/H+ exchanger in lamellar body membranes. The initial rates of quinacrine and oxonol V uptake were increased by bumetanide, but only in the presence of Na+, K+, and Cl-, suggesting that the lamellar bodies also contain an outwardly directed electroneutral Na(+)-K(+)-2Cl- cotransporter. Thus three ion transporters, H(+)-translocating V-ATPase, Na+/H+ exchanger, and Na(+)-K(+)-2Cl- cotransporter, appear to determine the chemical and electrical gradients across the lamellar body membrane.

Activation of host phospholipases C and D in macrophages after infection with Listeria monocytogenes.

Infection of the J774 murine macrophage-derived cell line with Listeria monocytogenes results in several elevations of intracellular calcium during the first 15 min of infection. These appear to result from the actions of secreted bacterial proteins, including phosphatidylinositol-specific phospholipase C (PI-PLC), a broad-range phospholipase C, and listeriolysin O (LLO) (S. J. Wadsworth and H. Goldfine, Infect. Immun. 67:1770-1778, 1999). We have measured hydrolysis of host PI and the activation of host polyphosphoinositide-specific PLC and host phospholipase D (PLD) during infection with wild-type and mutant L. monocytogenes. Elevated hydrolysis of host PI occurred within the first 10 min of infection and was dependent on both bacterial PI-PLC and LLO, both of which were required for the earliest elevations of intracellular calcium in the host cell. A more rapid hydrolysis of host PI was observed at 30 min after infection, at the time when wild-type bacteria have been internalized. Activation of host PLC, also occurred in the first 10 min of infection but was not dependent on the presence of bacterial PI-PLC. Similar observations were made in murine bone marrow-derived macrophages. In J774 cells, activation of host PLD was observed after 20 min of infection and was dependent on bacterial LLO. Mutants in the bacterial phospholipases produced levels of PLD activation similar to those produced by the wild type. Phorbol myristate acetate (PMA) also activated host PLD, while long-term treatment with PMA resulted in loss of the ability of L. monocytogenes to activate host PLD, suggesting an involvement of protein kinase C (PKC) in the activation of PLD. Rottlerin, an inhibitor of PKC delta in J774 cells, also inhibited the activation of PLD, but hispidin, an inhibitor of PKC betaI and betaII, did not. Pretreatment of J774 cells with the PLD inhibitor, 2, 3-diphosphoglycerate partially inhibited escape of the bacteria from the primary phagocytic vacuole.

Role of vacuolar adenosine triphosphatase in the regulation of cytosolic pH in hepatocytes.

The responses of the cytosolic pH of hepatocytes in suspension to agents affecting the activity of vacuolar adenosine triphosphatase (V-ATPase) and Na/H exchange have been studied. Changes of cytosolic pH were determined both with dual-wavelength excitation (500/440 nm) of the fluorescence of 2',7'-bis-(2-carboxyethyl)-5(and 6)-carboxyfluorescein and from the distribution of 14C-dimethyloxazolidinedione; both methods gave very similar results. Changes of vesicular pH were determined by comparing the fluorescence of fluorescein isothiocyanate-dextran and rhodamine B isothiocyanate-dextran taken up by endocytosis. Nitrate, which inhibits V-ATPase in isolated organelles, induced a concentration-dependent acidification of the cytosol and alkalinization of vesicles, with maximal effects at 25-37.5 mM in each case, indicating that V-ATPase contributes to removal of cytosolic protons. On continued exposure to nitrate, the acidification underwent an amiloride-inhibitable reversal. At the higher concentrations of NO3-, both cytosolic acidification and vesicular alkalinization were reduced or absent. Bafilomycin A1 caused alkalinization of vesicular pH; cytosolic acidification was not observed, possibly because of other ionic exchanges. Recovery of cytosolic pH from an acid load (2 min exposure to 5% CO2) was sensitive to both 25 mM NO3- and to ouabain. The pH dependence of the nitrate effect was tested with media of different pH; the activity was negligible at cytosolic pH 6.2 and rose to a maximum at cytosolic pH 7.3. Treatment of hepatocytes with 0.5-1.0 mM ouabain resulted in an initial alkalinization (0.5-2 min duration) of the cytosol, followed by a spontaneous reversal and, on occasion, further acidification. The alkalinization was blocked by 25 mM NO3-, but not by 25 mM gluconate. The results suggest that the cytosolic alkalinization is caused by a stimulation of H+ uptake by V-ATPase activity. We conclude that V-ATPase make an important contribution to the regulation of the cytosolic pH of hepatocytes.

Ras-dependent signaling by the GTPase-deficient mutant of Galpha12.

Galpha12 and Galpha13 regulate diverse responses through the small GTPases Ras, CDC42, Rac, and Rho. Whereas they activate similar responses in many different cell types, they also activate more specific and critical signaling pathways in other cell types. In COS cells, in which both Galpha12 and Galpha13 stimulate Na+/H+ exchange, they do so by activating different signaling pathways. Here we report that the differential recruitment of specific small GTPases by Galpha12 and Galpha13 defines the molecular basis for their functional differences. We have observed that the stimulation of Na+/H+ exchange by the GTPase-deficient mutant of Galpha12 (Galpha12QL) requires a functional Ras and is independent of Rac/CDC42 and Jun kinase signaling module. By contrast, the stimulation of Na+/H+ exchange by Galpha13QL requires a functional Rac/CDC42 and the Jun kinase signaling module. Our results also indicate that Galpha12QL-Ras stimulation of Na+/H+ exchange involves a D609-sensitive phospholipase and protein kinase C. These studies, for the first time, describe a novel Galpha12-specific signaling pathway involving Ras, phosphatidylcholine hydrolysis, and protein kinase C in the regulation of Na+/H+ exchange.

Cognitive ability and academic achievement in the Colorado Adoption Project: a multivariate genetic analysis of parent-offspring and sibling data.

To test the hypothesis that the etiology of covariation among measures of cognitive ability and academic achievement is due at least in part to shared genetic influences, data from 198 adoptive and 220 nonadoptive families participating in the Colorado Adoption Project were subjected to multivariate behavioral genetic analyses. Data on measures of cognitive ability (verbal comprehension and perceptual organization) and academic achievement (reading recognition and mathematics achievement) from related and unrelated sibling pairs tested at age 7, as well as from adoptive and nonadoptive parents, were analyzed. Phenotypic analyses confirmed previous findings of moderate correlations among measures of cognitive ability and achievement, averaging about .35. Although 54% of the covariation between reading and mathematics achievement was due to influences shared with verbal ability, a significant proportion of this covariation was independent of the cognitive ability measures. Heritabilities for the various measures were moderate, ranging from .21 to .37. Moreover, genetic influences accounted for 33-64% of their phenotypic covariation; for example, 33-60% of the observed correlations between verbal comprehension and the achievement measures, 64% of those between perceptual organization and the achievement measures, and 63% of that between reading recognition and mathematics achievement were due to shared genetic influences. Similar to the results of the phenotypic analysis, nearly half of the genetic covariance between reading and mathematics achievement was independent of cognitive ability. Their remaining covariance was due primarily to nonshared environmental influences.

Gender ratios among reading-disabled children and their siblings as a function of parental impairment.

Gender ratios are reported for 374 reading-disabled probands and their 530 siblings included in five independent studies of reading disability. Ratios were tabulated for each study as a function of parental impairment (neither parent affected, mother only affected, father only affected, and both parents affected). Results reveal a small excess of male probands in referred and clinic samples of reading-disabled children, but not in research-identified samples. Gender ratios among siblings of reading-disabled probands are approximately 1:1. In addition, combined results indicate that gender ratios of neither probands nor their siblings vary substantially as a function of parental impairment.

Protein kinase C-dependent and -independent activation of Na+/H+ exchanger by G alpha 12 class of G proteins.

Constitutively activated mutants of the G alpha 12 class of G proteins, G alpha 12(Q229L) and G alpha 13(Q226L), were transiently expressed in COS-1 cells, and the activity of amiloride-sensitive Na+/H+ exchanger was measured. The expression of either G alpha 12(Q229L) or G alpha 13(Q226L) increased the basal activity of the amiloride-sensitive exchanger by 2-5-fold. Regulation of this activation by other G protein signaling pathways was investigated by the transient expression of constitutively activated G protein mutants of G alpha s(Q227L), G alpha i2(Q205L), and G alpha q(Q209L) in COS-1 cells. Only G alpha q showed a similar activation of the exchanger. Chronic treatment of the transfected cells with 4 beta-phorbol 12-myristate 13-acetate to deplete the endogenous protein kinase C completely inhibited the activation of the antiporter by G alpha 12(Q229L), whereas activation by G alpha 13(Q226L) remained unaffected. These results indicated that both G alpha 12 and G alpha 13 can activate Na+/H+ exchanger by two distinct signaling pathways. G alpha 12 activation of the exchanger was dependent on protein kinase C pathway, whereas G alpha 13 activation was not. These studies define the involvement of G alpha 12 class of G proteins, for which no function has been assigned yet, in the activation of Na+/H+ exchanger.

Activated mutant of Galpha(12) enhances the hyperosmotic stress response of NIH3T3 cells.

Heterotrimeric G protein G12 stimulates diverse physiological responses including the activities of Na+/H+ exchangers and Jun kinases. We have observed that the expression of the constitutively activated, GTPase-deficient mutant of Galpha(12) (Galpha(12)QL) accelerates the hyperosmotic response of NIH3T3 cells as monitored by the hyperosmotic stress-stimulated activity of JNK1. The accelerated response appears to be partly due to the increased basal activity of JNK since cell lines-such as NIH3T3 cells expressing JNK1-in which JNK activity is elevated, show a similar response. NIH3T3 cells expressing Galpha(12)QL also display heightened sensitivity to hyperosmotic stress. This is in contrast to JNK1-NIH3T3 cells that failed to enhance sensitivity although they do exhibit an accelerated hyperosmotic response. Reasoning that the increased sensitivity seen in Galpha(12)QL cells is due to a signaling component other than JNK, the effect of dimethyamiloride, an inhibitor of Na+/H+ exchanger in this response, was assessed. Treatment of vector control NIH3T3 cells with 50 microM dimethylamiloride potently inhibited their hyperosmotic response whereas the response was only partially inhibited in Galpha(12)QL-NIH3T3 cells. These results, for the first time, identify that NHEs are upstream of the JNK module in the hyperosmotic stress-signaling pathway and that Galpha(12) can enhance this response by modulating either or both of these components namely, JNKs and NHEs in NIH3T3 cells.