Inducible expression of a p56Lck transgene reveals a central role for Lck in the differentiation of CD4 SP thymocytes

The T lymphocyte-specific protein tyrosine kinase p56lck (Lck) is an essential component of the TCR-mediated signal transduction complex. Lck knockout mice have reduced numbers of double-positive thymocytes and very few mature single-positive cells, particularly of the CD4 lineage. Here we demonstrate the ability of a tetracycline-based tissue-specific inducible Lck transgene to restore expansion of early thymocytes and maturation of single-positive cells in Lckneg mice upon induction with doxycycline. Restoration of Lck expression is particularly important for positive selection to the CD4+ lineage but has a lesser impact on selection to the CD8+ lineage, suggesting activation of Lck is an important component of the signals involved in lineage choice during thymic differentiation.

Regulation and developmental expression of the divalent metal-ion transporter in the rat brain

Divalent metal ion transporter 1 (DMT1) is a recently identified metal-ion transporter that appears to mediate the absorption of iron in the intestine. DMT1 mRNA is also present in discrete areas of the brain. In this study, we examined the expression of DMT1 mRNA in developing rat brain. DMT1 mRNA was found by in situ hybridization in the striatum, cortex, hippocampus and cerebellum. During development, DMT1 mRNA was found in Purkinje and granule cells in the cerebellum at post-natal day (PND) 14 and PND 30. DMT1 mRNA was also expressed in the external granular layer of the cerebellum at PND 14. No change in the level of DMT1 mRNA was observed by Northern analysis in the cerebellum at different ages between PND 1 and 21. DMT1 was found by Northern analysis in cultures of rat astrocytes. Activation of protein kinase C increased the expression of DMT1 in kidney epithelial cells but not astrocytes from newborn rats. Because DMT1 is expressed in a wide variety of types of cells, we suggest that it plays an important role in metal homeostasis in the brain.

Differential vulnerability of primary cultured cholinergic neurons to nitric oxide excess

Many neuronal nitric oxide synthase (nNOS)-expressing brain neurons, including some cholinergic populations, are resistant to disease or to certain forms of excitotoxicity. Vulnerability to NO excess of forebrain (medial septal/diagonal band; MS-ACh) and brainstem (pedunculopontine/laterodorsal tegmental nuclei; BS-ACh) cholinergic neurons was compared in E16-E18 primary rat brain cultures. MS-ACh cells were approximately 300-fold more sensitive to the NO donor S-nitro-N-acetyl-D,L-penicillamine (SNAP) than were BS-ACh cells. Most (69%) MS-ACh cells contained nuclear DNA fragments by 2 h after addition of SNAP, while only 21% BS-ACh cells were TUNEL-positive after NO excess. Depletion of glutathione content did not potentiate the effect of SNAP on MS-ACh cells, but sensitized BS-ACh cells to the NO donor. Caffeic acid, a putative NF-kappa B inhibitor, enhanced the toxicity of SNAP to cholinergic neurons in both preparations. Our experiments show that cholinergic neurons in mixed primary cultures from different brain regions possess biochemical differences with respect to their vulnerability to NO excess.

Prevalence and impact of urinary symptoms among community-dwelling stroke survivors

BACKGROUND AND PURPOSE

To establish prevalence of urinary symptoms among community-dwelling stroke survivors and how these symptoms affected lives of these survivors compared with a nonstroke population.

METHODS

The present study was a community-based postal survey in Leicestershire community, UK (that excluded institutional settings), that was designed to track stroke, urinary, and bowel symptoms and the effect of such symptoms on relationships, social life, daily activities, and overall quality of life. Subjects included 14 600 people who were living in the community and </=40 years of age, randomly selected from the Leicestershire Health Authority Register.

RESULTS

A 70% response rate was achieved with the return of 10 226 questionnaires. Prevalence of reported stroke was 4% (n=423). Prevalence of urinary symptoms was 34% (n=3197). Overall, stroke survivors had a higher prevalence of symptoms than the nonstroke population (64% to 32%, respectively). These symptoms were reported to have more of an effect on the lives of the stroke survivors compared with the nonstroke population even when adjusted for age and sex differences. This reported impact was not related to the stroke per se but to the severity of the urinary symptoms.

CONCLUSIONS

These data show a high prevalence of urinary symptoms among community-dwelling stroke survivors. These symptoms were reported to have considerable impact on the lives of stroke survivors, which needs to be taken into account in future research and clinical practice.

All trans retinoic acid induces apoptosis in acute promyelocytic NB4 cells when combined with isoquinolinediol, a poly(ADP-ribose) polymerase inhibitor

NB4 cells, a model of acute promyelocytic leukemia have been shown to undergo granulocytic differentiation in response to all trans retinoic acid (ATRA), or monocytic differentiation in response to 1alpha,25 dihydroxyvitamin D(3) (1,25 D(3)) and phorbol ester. We have shown previously that the expression of poly(ADP-ribose) polymerase (PARP) is dramatically increased during monocytic differentiation and completely down-regulated during neutrophilic differentiation. Here we show that NB4 cells simultaneously treated with ATRA and isoquinolinediol (Iso-Q), a specific PARP inhibitor, fail to differentiate into neutrophils. Nitroblue tetrazolium (NBT) dye reduction was inhibited by 48% and neutrophil formation was reduced by 75%. NB4 cells treated with ATRA and Iso-Q instead showed features of apoptosis including nuclear condensation, DNA fragmentation, and PARP cleavage yielding a 85 kDa fragment. NB4 cells treated with ATRA in combination with 1,25 D(3), a monocytic differentiation inducer, while continuing to reduce NBT also failed to mature into neutrophils or monocytes and again showed features of apoptosis. Down-regulation of Bcl-2 protein expression was evident in NB4 cells treated with ATRA and ATRA in combination with Iso-Q or 1,25 D(3), but not in cells treated with a classic chemotherapeutic agent, arabinosycytosine, suggesting that Bcl-2 down-regulation is neither necessary, nor specific for apoptosis in this model.

Serotonergic modulation of the P13 midlatency auditory evoked potential in the rat

The vertex-recorded, sleep state-dependent P13 midlatency auditory evoked potential in the rat may be generated, in part, by pedunculopontine nucleus (PPN) projections. Injections into the PPN of the 5-HT(1A) serotonin receptor agonist, 8-hydroxy-2-di-n-propylaminotetralin hydrobromide (DPAT), were found to reduce the amplitude of the P13 potential in a dose- and time-dependent manner. The suppressive effect of DPAT was blocked or reduced by pretreatment with the 5-HT(1A) serotonin receptor antagonist, Pindobind. These results show that the P13 potential can be modulated by known inhibitory serotonergic inputs to the PPN.

Effect of 3 medicaments on the dimensional accuracy and surface detail reproduction of polyvinyl siloxane impressions

OBJECTIVE

The purpose of this study was to determine the effect of retraction cord medicaments (aluminum chloride, ferric sulfate, and ferric subsulfate/ferric sulfate) on the dimensional accuracy and surface detail reproduction of polyvinyl siloxane impressions.

METHOD AND MATERIALS

Polyvinyl siloxane impressions were made of standardized metal dies (American Dental Association [ADA] specification No. 19) treated with 1 of the 3 retraction cord medicaments. Dimensional accuracy was evaluated by comparing the average length of a line in the impressions to the standard die. Surface detail reproduction was evaluated by viewing the impressions under low-angle illumination at x10 magnification. Reproduction was considered satisfactory if 2 of 3 horizontal lines were reproduced continuously. The dies were also evaluated under the microscope before the impression was made.

RESULTS

The medicaments did not significantly effect the dimensional accuracy; mean shrinkage was within ADA guidelines in the treatment groups. All of the medicaments had an adverse effect on surface detail reproduction. These effects were statistically significant compared to the untreated control.

CONCLUSION

Although the changes in dimensional accuracy were within ADA guidelines, the surface detail reproduction was modified such that the impression would be considered clinically unacceptable. For optimal results, care must taken to remove all traces of these retraction cord medicaments prior to recording of a polyvinyl siloxane impression.

Rapid separation of nitroaromatic compounds by solvating gas chromatography

Nitroaromatic compounds such as 2,4,6-trinitrotoluene are used in the production of explosive and munitions, and are environmental contaminants as a result of such use. Conventional methods to detect these compounds have relied on liquid and gas chromatography to isolate the individual compounds which may be present at low levels in complex environmental matrices before final detection and identification. A new method, solvating gas chromatography, was used to rapidly separate 8 nitroaromatic compounds, showing improved speed relative to conventional liquid and gas chromatography methods. Solvating gas chromatography allows near real-time detection for these energetic compounds, providing improvements in their detection as environmental contaminants, and as compounds of interest to law enforcement and military organizations.

Soluble antigen and CD40 triggering are sufficient to induce primary and memory cytotoxic T cells

The signals directing induction of tolerance rather than immunity are largely unknown. The CD8 T cell response to soluble Ags generally results in deletional tolerance following transient, costimulation-dependent activation. We demonstrated that CD40 signaling reversed the outcome of this response. Adoptive transfer of OVA-specific CD8 T cells followed by soluble OVA immunization resulted in induction of lytic activity and optimal clonal expansion only when CD40 was triggered via an agonistic mAb. Activation of CD8 T cells by CD40 signaling was indirect, because CD40 expression by host cells was required. CD40 signaling along with soluble Ag immunization also induced expansion of secondary lymphoid and intestinal mucosal endogenous OVA-specific CD8 T cells as detected by MHC tetramer reactivity. When CD40 activation was included, long-lived secondary lymphoid and mucosal memory CD8 cells were generated from adoptively transferred and endogenous CD8 T cells. Mucosal and peripheral CD8 memory cells exhibited constitutive Ag-specific lytic activity, with mucosal memory cells being 10-fold more lytic than splenic or lymph node memory cells. These results demonstrated that CD40 signaling during a response to a poorly immunogenic soluble Ag was necessary and sufficient for CTL and memory T cell induction.

Health professionals' baseline knowledge of oral/pharyngeal cancers

BACKGROUND

The purpose of this study was to evaluate: self-perceived competency in screening for oral/pharyngeal cancers (OPCs); knowledge about their signs, symptoms, and risk factors; and percentage of patients routinely examined.

METHODS

Of 352 health professionals who completed an assessment, a subgroup of 110 physicians and dental providers was identified. Thirty-three of those had advanced training (AT) related to the oral cavity and 77 were primary care physicians (PCPs).

RESULTS

Only 7% of the PCPs reported examining 100% of their patients for OPCs. A greater percentage of the PCP group than the AT group felt their knowledge about OPCs was not up to date (p < 0.05) and inaccurately identified common signs and sites of early OPCs. A greater percentage (p < 0.05) of the PCP group also reported the need for additional training.

CONCLUSION

These results suggest the need for OPC educational programs aimed toward health care providers without advanced training related to the oral cavity.

Bladder training for urinary incontinence in adults

BACKGROUND

Bladder training is widely used for the treatment of urinary incontinence. It is generally used for the treatment of people with urge incontinence or detrusor instability, although it is also thought that it might be of use for people with mixed incontinence or stress incontinence.

OBJECTIVES

To assess the effects of bladder training for the treatment of urinary incontinence.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group trials register up to July 1999. Date of the most recent search: July 1999.

SELECTION CRITERIA

Randomised or quasi-randomised trials of bladder training for the treatment of incontinence.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data that were then cross-checked by the third reviewer. All three reviewers assessed trial quality.

MAIN RESULTS

We found seven eligible trials with a total of 259 predominantly female patients with urinary urge incontinence. The quality of trials was variable. Three trials involving 92 women compared bladder training with no bladder training. These tended to favour bladder training but data were available for only a limited number of pre-specified outcomes that varied across the three trials. No data describing long term follow up are available. One trial compared bladder training with drug therapy, but was inconclusive. Another trial compared bladder training with an electronic prompt device. The trial was small and included only 20 women. Data were not presented in a form suitable for quantitative analysis. Two further trials compared bladder training supplemented by drug therapy with bladder training alone. Again, the limited data provided insufficient evidence on which to draw conclusions.

REVIEWER'S CONCLUSIONS

Bladder training may be helpful for the treatment of urinary urge incontinence, but this conclusion can only be tentative, based on the evidence available. There was not enough evidence to show whether drug therapy was better than bladder training or useful as a supplement to it.

Multiplex Reverse Transcriptase PCR Assay for Simultaneous Detection of Three Fish Viruses

A multiplex reverse transcriptase (RT)-PCR assay was developed for the simultaneous detection of three different fish viruses: infectious pancreatic necrosis virus (IPNV), infectious hematopoietic necrosis virus (IHNV), and viral hemorrhagic septicemia virus (VHSV). The sensitivity levels of the multiplex RT-PCR assay were 100, 1, and 32 50% tissue culture infective doses/ml for IPNV, IHNV, and VHSV, respectively.

Unstable dimension variability in coupled chaotic systems

Systems of coupled chaotic maps and flows arise in many situations of physical and biological interest. The aim of this paper is to analyze and to present numerical evidence for a common type of nonhyperbolic behavior in these systems: unstable dimension variability. We show that unstable periodic orbits embedded in the dynamical invariant set of such a system can typically have different numbers of unstable directions. The consequence of this may be severe: the system cannot be modeled deterministically in the sense that no trajectory of the model can be realized by the natural chaotic system that the model is supposed to describe and quantify. We argue that unstable dimension variability can arise for small values of the coupling parameter. Severe modeling difficulties, nonetheless, occur only for reasonable coupling when the unstable dimension variability is appreciable. We speculate about the possible physical consequences in this case.

Universal, developmental, and variable aspects of young children's play: a cross-cultural comparison of pretending at home

Using longitudinal data from five Irish American families in the United States and nine Chinese families in Taiwan, in conjunction with an emerging body of evidence in the cultural psychology literature, we propose universal, culturally variable, and developmental dimensions of young children's pretend play. Possible universal dimensions include the use of objects, and the predominantly social nature of pretend play. Developmental dimensions include increases in the proportion of social pretend play initiated by the child, the proportion of partner initiations elaborated upon by the child, and caregivers' use of pretend play initiations to serve other, nonplay social functions. Culturally variable dimensions include the centrality of objects, the participation of specific play partners, the extent of child initiations of social pretend play with caregivers, the various functions of social pretend play in interaction, and specific themes. These findings raise the theoretical issue of how universal and variable dimensions of pretend play interact in specific communities to create distinctive development pathways.

Evaluation of apomorphine HCl effects on reproductive endpoints: studies in male rats and dogs

Apomorphine HCl is currently in phase III clinical trials for the treatment of erectile dysfunction. The potential for reproductive toxicity in males was assessed based on a 13-week rat study--a fertility study in male rats--and a 6-month study in dogs. The subcutaneous (s.c.) route was selected to simulate the sublingual route in humans. Dosages of apomorphine were 0.0 (vehicle), 0.8, 2, and 8 mg/kg/day in the 13-week study in rats (20/group), with 8 mg/kg/day used for only 9 weeks. In the fertility study, 24 males/group were cohabited with females, and doses were 0.0, 0.2, 0.8, and 2 mg/kg/day. Males were treated for 4 weeks prior to cohabitation and for 5 weeks throughout cohabitation. Organ weights, including testis and left epididymis, sperm count and morphology in the epididymis, and sperm motility in the vas deferens were evaluated. Male fertility index, and in females, the numbers of fetuses, implantation sites, and corpora lutea were counted. Male dogs (five/group) were dosed with 0.04, 0.1, or 0.4 mg/kg/day for 6 months. Epididymal and prostate weight, and testicular and epididymal histology were evaluated. Daily morbidity/mortality, weekly clinical observations, body weight, and food consumption were evaluated in all studies. No adverse effect was observed in any of the reproductive parameters in the studies. The NOEL for reproductive toxicity was approximately equal to 0.4 mg/kg/day in dogs and > or = 2 mg/kg/day in rats. These doses in rats and dogs correlated with plasma levels of approximately 240 and 130 ng/mL, and AUCs of 200 and 100 ng.h/mL, respectively. These levels suggest a safety margin for the evaluated male reproductive endpoints of at least 104 times based on the Cmax, and 44 times based on AUC of the clinical dose.

HIV-1 Nef mediates lymphocyte chemotaxis and activation by infected macrophages

Infection of macrophage lineage cells is a feature of primate lentivirus replication, and several properties of primate lentiviruses seem to have evolved to promote the infection of macrophages. Here we demonstrate that the accessory gene product Nef induces the production of two CC-chemokines, macrophage inflammatory proteins 1alpha and 1beta, by HIV-1-infected macrophages. Adenovirus-mediated expression of Nef in primary macrophages was sufficient for chemokine induction. Supernatants from Nef-expressing macrophages induced both the chemotaxis and activation of resting T lymphocytes, permitting productive HIV-1 infection. These results indicate a role for Nef in lymphocyte recruitment and activation at sites of virus replication.

Stimulatory and inhibitory properties of aminoglycoside antibiotics at N-methyl-D-aspartate receptors

The effects of aminoglycoside antibiotics on N-methyl-D-aspartate (NMDA) receptors were studied using voltage-clamp recording of recombinant NMDA receptors expressed in Xenopus oocytes. A number of aminoglycosides were found to potentiate macroscopic currents at heteromeric NR1A/NR2B receptors, but not at NR1A/NR2A, NR1A/NR2C, NR1A/NR2D, or NR1B/NR2B receptors. The degree of potentiation had a rank order neomycin B > paromomycin > gentamicin C > geneticin > kanamycin A > streptomycin. Potentiation was not seen with kasugamycin and spectinomycin. The degree of stimulation paralleled the number of the amino groups in the aminoglycosides. The stimulatory effects of aminoglycosides were more pronounced at subsaturating concentrations of glycine and at acidic pH, similar to the stimulatory effects of spermine. We measured the effects of aminoglycosides at mutant NMDA receptors to determine which amino acid residues in NMDA receptor subunits are involved in stimulation. Mutations that reduced or abolished spermine stimulation also reduced stimulation by aminoglycosides. Several aminoglycosides produced a weak voltage-dependent block of NMDA receptors, but the degree of inhibition did not appear to correlate with the number of amino groups in the molecule. The results suggest that aminoglycosides having more than three amino groups have stimulatory effects that are mediated through the spermine-binding site on NMDA receptors.

Perceived and physiological indicators of relaxation: as different as Mozart and Alice in chains

The effects of listening to different types of music on perceived and physiological indicators of relaxation were evaluated. Fifty-six undergraduate students, 24 males and 32 females, mean age of 21, were randomly assigned to listen to classical, hard rock, self-selected relaxing music, or no music. Participants' relaxation level, skin temperature, muscle tension and heart rate were evaluated before and after exposure to a music condition. Analyses of variance using baseline measures as covariates indicated that skin temperature decreased for all conditions (p = 0.001) and the classical, self-selected relaxing music and no music groups reported significant increases in feelings of relaxation (p = 0.004). These results partially support the hypothesis that classical and self-selected relaxing music can increase perceptions of relaxation to a greater degree than listening to hard rock music. However, no differences were found between different types of music on physiological indicators of arousal. Implications for using music to reduce stress were discussed.

tRNA prefers to kiss

Six RNA aptamers that bind to yeast phenylalanine tRNA were identified by in vitro selection from a random-sequence pool. The two most abundantly represented aptamers interact with the tRNA anticodon loop, each through a sequence block with perfect Watson-Crick complementarity to the loop. It was possible to truncate one of these aptamers to a simple hairpin loop that forms a classical 'kissing complex' with the anticodon loop. Three other aptamers have nearly complete complementarity to the anticodon loop. The sixth aptamer has two sequence blocks, one complementary to the tRNA T loop and the other to the D loop; this aptamer binds better to a mutant tRNA that disrupts the normal D-loop/T-loop tertiary interaction than to the wild-type tRNA. Selection of complements to tRNA loops occurred despite an attempt to direct binding to tertiary structural features of tRNA. This serves as a reminder of how special the RNA-RNA interactions are that are not based on complementarity. Nonetheless, these aptamers must present the tRNA complement in some special structural context; the simple single-strand complement of the anticodon loop did not bind tRNA effectively.

Th cells and Th2 responses can develop in the absence of MHC class II-CD4 interactions

In this paper, we address the question whether CD4 and MHC class II expression are necessary for the development of the T helper lineage during thymocyte maturation and for activation-induced Th2 responses. To bypass the CD4-MHC class II interaction requirements for positive selection and activation, we used mice that are doubly transgenic for CD8 and for the MHC class I-restricted TCR F5. This transgene combination leads to MHC class I-dependent maturation of CD4 lineage cells. Upon activation, these CD4 lineage T cells secrete IL-4 and give help to B cells but show no cytotoxic activity. Remarkably, neither MHC class II nor CD4 expression are necessary for the generation and helper functions of these cells. This suggests that under normal conditions, coreceptor-MHC interactions are necessary to ensure the canonical combinations of coreceptor and function in developing thymocytes, but that they do not determine functional commitment. Our results also imply that expression of the CD4 gene does not influence, but is merely associated with the decision to establish the T helper program. In addition, we show that activation through TCR-MHC class I interactions can induce Th2 responses independently of CD4 and MHC class II expression.