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Biomedical subjects

S Nowicki

Publications and source records attributed to S Nowicki.

At least 37 records · Page 2Linked to original sources
PubMed2000

L-Dopa uptake and dopamine production in proximal tubular cells are regulated by beta(2)-adrenergic receptors.

This study assessed the role of adrenergic receptors on the regulation of the uptake of L-dopa and the production of dopamine by renal tubular cells. Scatchard analysis showed two L-dopa uptake sites with different affinities (K(m) 0.316 vs 1.53 microM). L-Dopa uptake was decreased by the nonselective adrenergic agonists epinephrine or norepinephrine (40%), by the beta-selective agonist isoproterenol or the beta(2)-selective agonist terbutaline (60%), but not by alpha-selective agonists (all 1 microM). The effect of norepinephrine, isoproterenol, or terbutaline was unaffected by addition of the beta(1)-antagonist atenolol, abolished by ICI-118, 551, a beta(2)-antagonist (both 0.1 microM), and mimicked by the addition of dibutyryl-cAMP (1 microM). Preincubation with terbutaline decreased the number of high-affinity uptake sites (V(max) = 1.10 +/- 0.3 vs. 0.5 +/- 0.1 pmol. mg protein(-1). min(-1)) without changing their affinity. Norepinephrine or terbutaline decreased dopamine production by isolated cells, and this effect was abolished by ICI-118,551 (0.1 microM). In vivo administration of ICI-118,551 reduced the urinary excretion of L-dopa and increased the excretion of 3,4-dihydroxyphenylacetic acid without significant changes in plasma L-dopa concentrations. These results demonstrate that stimulation of beta(2)-adrenergic receptors decreases the number of high-affinity L-dopa uptake sites in isolated tubular cells resulting in a reduction of the uptake of L-dopa and the production of dopamine and provide evidence for the presence of this mechanism in the intact animal.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

Vocal tract function in birdsong production: experimental manipulation of beak movements.

Kinematic analyses have demonstrated that the extent to which a songbird's beak is open when singing correlates with the acoustic frequencies of the sounds produced, suggesting that beak movements function to modulate the acoustic properties of the vocal tract during song production. If motions of the beak are necessary for normal song production, then disrupting the ability of a bird to perform these movements should alter the acoustic properties of its song. We tested this prediction by comparing songs produced normally by white-throated sparrows and swamp sparrows with songs produced when the beak was temporarily immobilized. We also observed how temporarily loading the beak of canaries with extra mass affected vocal tract movements and song production. Disruption of vocal tract movements resulted in the predicted frequency-dependent amplitude changes in the songs of both white-throated sparrows and swamp sparrows. Canaries with mass added to their beak sang with their beak open more widely than normal and produced notes with greater harmonic content than those without weights. Both manipulations resulted in acoustic changes consistent with a model in which beak motions affect vocal tract resonances, thus supporting the hypothesis that dynamic vocal tract motions and post-production modulation of sound are necessary features of normal song production.

Acoustics↗
PubMed1999

The development of within-song type variation in song sparrows.

We investigated the development of within-song type variation in song sparrows, Melospiza melodia, with two experiments designed to determine how exposure to within-type variation influences the song-learning process and whether within-type variation itself is a learned trait. In the first experiment, we compared learning between two groups of males, one group tutored exclusively with song models presented with no variation, and the other group tutored exclusively with song models presented with a range of within-type variation that is normally produced by birds in the field. The two groups in this experiment did not differ significantly in any measure of how well they learned, suggesting that exposure to within-type variation has no measurable influence on the learning process overall. Nor did the groups differ in the expression of within-song type variation in their own adult songs, demonstrating that within-type variation is not a learned feature of song sparrow song. In the second experiment, we tutored a single group of birds with both invariant and variable models, allowing us to ask how within-type variability affects learning preferences. Young birds preferentially copied song type models presented with variation significantly more than invariant models. Taken together, these experiments provide insight into the evolution of within-song type variation in song sparrows, although the functional significance of this level of variation and learning preferences based on variation remain enigmatic. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Song types as fundamental units in vocal repertoires.

We investigated whether song types function as fundamental units of song variation in song sparrows, Melospiza melodia. As the size of a male song sparrow's repertoire increases, so does the mean similarity of his song types, as measured by the sharing of minimal units of production (MUPs). It follows that if MUP similarity is important perceptually, then small repertoires (of dissimilar song types) may be functionally equivalent to large repertoires (of similar song types). We performed two experiments to test whether MUP similarity is important perceptually to male song sparrows. Both experiments used a habituation/recovery design, in which recovery in response at a switch in stimuli is used to gauge the subject's perception of the similarity of the stimuli. The results of both experiments indicate that the level of perceived similarity between pairs of songs does not depend on their level of MUP similarity, within the range of MUP similarities found between song types. Songs with high enough MUP similarity to be judged as variants of the same song type are, however, perceived to be much more similar than are any two song types. The results are compatible with a categorical model of song type perception. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Permissiveness in the learning and development of song syntax in swamp sparrows.

Vocal learning in swamp sparrows, Melospiza georgiana, is subject to a host of sensory and motor limitations. One such limitation is that young swamp sparrows almost invariably crystallize their songs with a simple trilled syntax, irrespective of the syntax of vocal models from which they learn. A striking exception to this pattern was recently identified by Podos (1996, Animal Behaviour, 51, 1061-1070), who found that large-scale organizational changes in vocal syntax, including the production of an intermittent or 'broken' syntax, were produced when birds faced limits on vocal performance capacities during motor ontogeny. Our goal in the present study was to determine whether song models with broken syntax could serve as suitable training models for young swamp sparrows, and, if so, if broken syntax could be faithfully reproduced. We hand-reared 10 male swamp sparrows and exposed them to control, rapid and broken song models. Control song models were copied with a high degree of accuracy, as in previous studies. Rapid song models were copied with deficiencies that suggested performance limits on vocal production; such deficiencies included the production of songs with broken syntax and the production of songs in which notes were dropped out as songs progressed. Broken songs proved suitable as training models. Furthermore, copies of broken song models were crystallized either with normal or with broken syntax. These data identify an unexpected direction of permissiveness in the types of songs swamp sparrows will memorize and accurately reproduce, and also point to a possible proximate basis for syntactical changes in the evolution of sparrow songs. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Inverse relationship between severity of experimental pyelonephritis and nitric oxide production in C3H/HeJ mice.

The contribution of nitric oxide to host resistance to experimental pyelonephritis is not well understood. We examined whether the inhibition of nitric oxide synthesis alters the sensitivity of lipopolysaccharide (LPS) responder (C3H/HeN) and nonresponder (C3H/HeJ) mice to experimental Escherichia coli pyelonephritis. C3H/HeJ and C3H/HeN mice were implanted subcutaneously with minipumps containing an inhibitor of nitric oxide, NG-nitro-L-arginine methyl ester (L-NAME), or a corresponding vehicle. Ascending urinary tract infection by bladder catheterization with two strains of E. coli, an O75 strain bearing Dr fimbriae and an O75 strain bearing P fimbriae, was developed in tested animals. Twenty-four hours following bladder infection, the kidneys of C3H/HeN and C3H/HeJ mice were colonized at a similar rate. However, 5 weeks postinoculation, C3H/HeN mice cleared infection while C3H/HeJ mice showed persistent colonization. Twenty-four hours following infection, C3H/HeN mice treated with L-NAME showed no significant increase of renal tissue infection compared to the saline-treated control group. However, L-NAME-treated C3H/HeJ mice showed an approximately 100-fold increase in E. coli infection rate compared to the saline-treated controls in the Dr+ group but showed no change compared to those in the P+ group. Dissemination of Dr+ E. coli but not P+ E. coli to the liver and uterus was significantly enhanced with L-NAME treatment in C3H/HeJ mice only. Nitric oxide had no direct killing effect on E. coli in vitro. Nitrite production by various organs was found to be significantly lower in C3H/HeJ mice than in C3H/HeN mice. Alteration of nitric oxide and LPS responsiveness was significantly associated with the increased sensitivity of C3H/HeJ mice to experimental Dr+ but not to P+ E. coli pyelonephritis. These findings are consistent with the hypothesis that nitric oxide synthase activity in concert with LPS responsiveness may participate in the antibacterial defense mechanisms of the C3H mouse urinary tract. This phenomenon is strain dependent and possibly related to the invasive properties of E. coli.

Animals↗
PubMed1999

Experimental transmission of Neisseria gonorrhoeae from pregnant rat to fetus.

Sprague-Dawley rats were infected on day 20 of pregnancy by intraperitoneal inoculation with Neisseria gonorrhoeae. Disseminated gonococcal infection (DGI) and pelvic inflammatory disease (PID) strains in the presence of C1q but not in the presence of bovine serum albumin (BSA) were able to spread from the pregnant rat to the fetus and resulted in fetal mortality. Transmission of DGI and PID strains that are serum resistant (ser(r)) and sac-4 positive but not of a local infection strain that is ser(s) and sac-4 negative was facilitated by the C1q-dependent mechanism. This study provides the first experimental model that may mimic the transmission of gonococcal infection from mother to the fetus during pregnancy.

Animals↗
PubMed1999

Potential role of glycerol leading to rat fructose hypertension.

A fructose-enriched diet promotes hypertension in rats. We thought that an enhancement of the glycolytic and/or lipid disorder (s) that raise blood pressure could be the cause. Therefore, we studied 4 groups of Sprague-Dawley rats (+/-200 g): (1) control rats received a standard diet and tap water; (2) the glycerol group of rats received a standard diet and 0.54 mol/L glycerol in tap water; (3) the fructose group was given a fructose-enhanced diet (chow had 55% fructose instead of dextrin) and tap water; and (4) the fructose-glycerol group was given the fructose-enhanced diet and 0. 54 mol/L glycerol in drinking water. At the end of the second week, the findings were as follows. Blood pressure was 149+/-2 mm Hg in the fructose-glycerol group versus 129+/-2 (P<0.001), 131+/-2 (P<0. 001), and 140+/-3 (P<0.005) mm Hg in the control, glycerol, and fructose groups, respectively. Insulinemia was higher in the fructose-glycerol group than the control (P<0.001), glycerol (P<0. 001), and fructose groups (P<0.001); triglyceridemia was higher in the fructose-glycerol (P<0.02), fructose (P<0.05), and glycerol groups (P<0.02) than the control group. Thoracic aorta rings showed a lower ED(50) to 12,13-phorbol dibutyrate in the fructose-glycerol group than in the control (P<0.001), glycerol (P<0.002), and fructose groups (P<0.001). In conclusion, glycerol-fructose administration resulted in hypertriglyceridemia, hyperinsulinemia, and increased vascular sensitivity to 12,13-phorbol dibutyrate (with respect to the control group), and significantly greater expression of protein kinase C alpha and betaII (with respect to the glycerol group).

Animals↗
PubMed1998

The renal dopamine system.

Intrarenally formed dopamine induced natriuresis by inhibiting the activity of renal tubular Na/KATPase. This effect is mediated via a complex signal network, which includes inhibition of PP1 via the adenylyl cyclase-PKA-DARPP32 pathway and activation of PKC via the PLA2-arachidonic acid-20HETE pathway. The renal dopamine availability is a major determinant of the natriuretic effect of dopamine and is to a large extent modulated by the activity of COMT. The possibility that regulation of dopamine storage and release influences renal dopamine effects should be considered.

Adenylyl Cyclases↗
PubMed1998

Accuracy in identifying affect in child and adult faces and voices and social competence in preschool children.

The association between social competence and preschool children's ability to identify affect in child and adult facial expressions and tones of voice was investigated in 2 studies. A Sullivan theoretical framework was used. Results indicate that gender plays an important role in the association. For boys, accuracy in identifying low-intensity adult faces and, to a lesser extent, low-intensity adult voices was related to social competence regardless of whether social competence was being measured in interactions with other children or with adults. In contrast, for girls, the ability to read high-intensity expressions across child and adult faces and voices was more specifically related to social competence, depending on whether it was defined by interactions with children or adults. Social competence at this age seems to involve different types of nonverbal skills for boys and girls.

Adult↗
PubMed1997

Development of experimental model of chronic pyelonephritis with Escherichia coli O75:K5:H-bearing Dr fimbriae: mutation in the dra region prevented tubulointerstitial nephritis.

Escherichia coli that express Dr fimbriae and related adhesins recognize the common receptor decay accelerating factor. E. coli strains that express adhesins of the Dr family were postulated to be associated with cystitis (30-50%), pregnancy-associated pyelonephritis (30%), and chronic diarrhea (50%). In this study, we investigated the hypothesis that E. coli renal interstitial binding mediated by the Dr adhesin may be important for the development of chronic pyelonephritis. An insertional dra mutant, E. coli DR14, of the clinical E. coli isolate IH11128 bearing Dr fimbriae, was constructed and used to characterize persistence of infection and interstitial tropism in an experimental model of ascending pyelonephritis. Quantitative cultures of kidney homogenates indicated that Dr hemagglutinin positive (Dr+) E. coli IH11128 established a 1-yr colonization of renal tissue. In the Dr hemagglutinin negative (Dr-) group, 50% of animals cleared infection within 20 wk and 100% between 32 to 52 wk. Dr+ E. coli colonized the renal interstitium. Significant histological changes corresponding to tubulointerstitial nephritis including interstitial inflammation, fibrosis, and tubular atrophy were found in the kidney tissue of the Dr+ but not the Dr- group. A substantial amount of fimbrial antigen was detected in the parenchymal regions affected by interstitial inflammation and fibrosis. The obtained results are consistent with the hypothesis that mutation within the dra region, affecting E. coli binding to tubular basement membranes, prevented renal interstitial tropism and the development of the changes characteristically seen in tubulointerstitial nephritis.

Animals↗
PubMed1997

20-Hydroxyeicosa-tetraenoic acid (20 HETE) activates protein kinase C. Role in regulation of rat renal Na+,K+-ATPase.

It is well documented that the activity of Na+,K+-ATPase can be inhibited by the arachidonic acid metabolite, 20-hydroxyeicosa-tetraenoic acid (20 HETE). Evidence is presented here that this effect is mediated by protein kinase C (PKC). PKC inhibitors abolished 20 HETE inhibition of rat Na+,K+-ATPase in renal tubular cells. 20 HETE caused translocation of PKC alpha from cytoplasm to membrane in COS cells. It also inhibited Na+,K+-ATPase activity in COS cells transfected with rat wild-type renal Na+,K+-ATPase alpha1 subunit, but not in cells transfected with Na+,K+-ATPase alpha1, where the PKC phosphorylation site, serine 23, had been mutated to alanine. PKC-induced phosphorylation of rat renal Na+,K+-ATPase, as well as of histone was strongly enhanced by 20 HETE at the physiologic calcium concentration of 1.3 microM, but not at the calcium concentration of 200 microM. The results indicate that phospholipase A2-arachidonic acid-20 HETE pathway can exert important biological effects via activation of PKC and that this effect may occur in the absence of a rise in intracellular calcium.

Animals↗
PubMed1997

The association between receptive nonverbal processing abilities and internalizing/externalizing problems in girls and boys.

Social adjustment correlates of individual differences in receptive nonverbal processing abilities in boys and girls were investigated. Participants were 26 boys and 13 girls, mean age 12.04 years, who were in a custodial care institution for the treatment of a wide range of psychological difficulties. They completed the Diagnostic Analysis of Nonverbal Accuracy (DANVA; Nowicki & Duke, 1994), a standardized test of receptive nonverbal processing abilities. Trained raters used institutional records to assess the number and type of problems (internalizing or externalizing) experienced by each child. Teachers completed a social adjustment scale for each child. Girls' scores on the DANVA tests of child facial expression, child and adult facial expression combined, posture, and total DANVA accuracy as well as teacher ratings of social adjustment were significantly related to the number of externalizing problems they had. No other relations were significant. The findings suggest that receptive nonverbal processing skills may be more important for social adjustment for girls than for boys.

Adolescent↗
PubMed1997

The relation of nonverbal processing ability of faces and voices and children's feelings of depression and competence.

The relation between nonverbal processing ability and feelings of depression and competence was evaluated in children between the ages of 7 and 11 years (N = 142). They were administered tests to measure their receptive nonverbal ability and feelings of depression and competence. Hierarchical regression analyses revealed that nonverbal ability was related to feelings of competence in boys and girls, but to feelings of depression only in boys. It was concluded that specific nonverbal deficits are associated with generalized negative feelings in children. Implications for adjustment are discussed.

Child↗
PubMed1997

Awareness of interpersonal style and self-evaluation.

Interpersonal theorists assume that the greater the discrepancy between a person's own assessment of his or her interpersonal style and the perceptions of others, the greater will be that individual's reported psychological distress. In the present study, 32 U.S. undergraduate students, all female, completed the Interpersonal Checklist (ICL) of LaForge and Suczek (1955) to measure their interpersonal styles and the Symptom Distress Checklist-Revised (SCL-90-R) of Derogatis (1983) to measure their psychological distress. On the basis of their ICL scores, they were placed with complementary partners of the same sex to interact for 7 min. Verbal transcripts and soundless videotapes were prepared from the videotapes of their interactions. After either reading the verbal transcript or watching the soundless videotape, raters completed an ICL describing the impression each participant was communicating. When, on the basis of either the videotape or the transcript, raters judged a participant as more dominant than the participant judged herself, the discrepancy was significantly related to SCL-90-R scale scores on Positive Symptom Total, Global Severity Index, Interpersonal Sensitivity, Anxiety, and Depression. The results supported the assumption that self-other discrepancy was associated with psychological difficulties, especially when the discrepancy involved participants believing themselves less dominant than others perceived them.

Adult↗
PubMed1997

Physical fitness as a function of psychological and situational factors.

The association between personality variables suggested by Rotter's social learning theory and indices of physical fitness was examined in a sample of U.S. college students. As predicted, both higher value placed on physical fitness and greater internal locus of control were related to selected indicators of physical fitness. In addition, gender of administrator affected performance on certain measures of physical fitness. The results suggest the need for longitudinal studies to evaluate the role of physical activity in mediating the relationship between personality variables and physical fitness.

Adult↗
PubMed1997

Dr fimbriae operon of uropathogenic Escherichia coli mediate microtubule-dependent invasion to the HeLa epithelial cell line.

Escherichia coli Dr adhesin and decay-accelerating factor (DAF) receptor-mediated interaction was proposed as the mechanism of ascending urinary tract infection (UTI) and chronic interstitial nephritis. This report provides novel evidence for Dr fimbriae operon-mediated invasive capacity of Dr+ E. coli. Insertional mutants draE, draC, and draB, and adherent draD and UV-inactivated BN406 were unable to enter HeLa cells. Complementation of the dra mutation restored invasiveness. Internalization was inhibited by anti-Dr fimbriae IgG (100%), anti-SCR-3 domain of DAF (75%), and nocodazole (95%). Increased receptor-ligand density occurred at the site of internalization. Internalized Dr+ E. coli did not significantly multiply in the HeLa cell line. Accordingly, the dra operon and DAF were required for microtubule-dependent internalization of E. coli to HeLa cells. The relatively low invasion and multiplication rates of Dr+ E. coli may hypothetically contribute to the postattachment steps of ascending UTI and chronic renal infection.

Adhesins, Escherichia coli↗