Towards REPO4 nanocrystal-doped optical fibers for distributed sensing applications

Rayleigh scattering enhanced nanoparticle-doped optical fibers, for distributed sensing applications, is a new technology that offers unique advantages to optical fiber community. However, the existing fabrication technology, based on in situ grown alkaline earth nanoparticles, is restricted to few compositions and exhibit a great dependence on many experimental conditions. Moreover, there is still several uncertainties about the effect of drawing process on the nanoparticle characteristics and its influence on the scattering enhancement and the induced optical loss. In this work, we shed light on all these issues that prevent the progress in the field and demonstrate the suitability of doping optical fibers with YPO4 nanocrystals for developing tunable Rayleigh scattering enhanced nanoparticle-doped optical fibers. An exhaustive 3D microstructural study reveals that their features are closely linked to the fiber drawing process, which allow the size and shape engineering at the nanoscale. In particular, the YPO4 nanocrystals preserve their features to a large extent when the optical fibers are drawn below 1950 °C, which allows obtaining homogeneous nanocrystal features and optical performance. Fabricated fibers exhibit a tunable enhanced backscattering in the range of 15.3-54.3 dB, with respect to a SMF-28 fiber, and two-way optical losses in the range 0.3-160.7 dB/m, revealed by Optical Backscatter Reflectometry (OBR) measurements. This allows sensing lengths from 0.3 m up to more than 58 m. The present work suggests a bright future of YPO4 nanocrystals for distributed sensing field and open a new gate towards the incorporation of other rare-earth orthophosphate (REPO4) nanocrystals with pre-defined characteristics that will overcome the limitations of the current in situ grown alkaline earth-based technology.

Suppression of the necroptotic cell death pathways improves survival in Smn2B/− mice

Spinal muscular atrophy (SMA) is a monogenic neuromuscular disease caused by low levels of the Survival Motor Neuron (SMN) protein. Motor neuron degeneration is the central hallmark of the disease. However, the SMN protein is ubiquitously expressed and depletion of the protein in peripheral tissues results in intrinsic disease manifestations, including muscle defects, independent of neurodegeneration. The approved SMN-restoring therapies have led to remarkable clinical improvements in SMA patients. Yet, the presence of a significant number of non-responders stresses the need for complementary therapeutic strategies targeting processes which do not rely solely on restoring SMN. Dysregulated cell death pathways are candidates for SMN-independent pathomechanisms in SMA. Receptor-interacting protein kinase 1 (RIPK1) and RIPK3 have been widely recognized as critical therapeutic targets of necroptosis, an important form of programmed cell death. In addition, Caspase-1 plays a fundamental role in inflammation and cell death. In this study, we evaluate the role of necroptosis, particularly RIPK3 and Caspase-1, in the Smn^2B/− mouse model of SMA. We have generated a triple mutant (TKO), the Smn^2B/−; Ripk3^−/−; Casp1^−/− mouse. TKO mice displayed a robust increase in survival and improved motor function compared to Smn^2B/− mice. While there was no protection against motor neuron loss or neuromuscular junction pathology, larger muscle fibers were observed in TKO mice compared to Smn^2B/− mice. Our study shows that necroptosis modulates survival, motor behavior and muscle fiber size independent of SMN levels and independent of neurodegeneration. Thus, small-molecule inhibitors of necroptosis as a combinatorial approach together with SMN-restoring drugs could be a future strategy for the treatment of SMA.

The EEG correlates and dangerous behavioral consequences of drowsy driving after a single night of mild sleep deprivation

OBJECTIVE

Here, we investigated the behavioral, cognitive, and electrophysiological impact of mild, acute sleep loss via simultaneously recorded behavioral and electrophysiological measures of vigilance during a "real-world", simulated driving task.

METHODS

Participants (N = 34) visited the lab for two testing days where their brain activity and vigilance were simultaneously recorded during a driving simulator task. The driving task lasted approximately 70 mins and consisted of tailgating the lead car at high speed, which braked randomly, requiring participants to react quickly to avoid crashing. The night before testing, participants either slept from 12am-9am (Normally Rested), or 1am-6am (Sleep Restriction).

RESULTS

After a single night of mild sleep restriction, sleepiness was increased, participants took longer to brake, missed more braking events, and crashed more often. Brain activity showed more intense alpha burst activity and significant changes in EEG spectral power frequencies related to arousal (e.g., delta, theta, alpha). Importantly, increases in amplitude and number of alpha bursts predicted delays in reaction time when braking.

CONCLUSIONS

The findings of this study suggest that a single night of mild sleep loss has significant, negative consequences on driving performance and vigilance, and a clear impact on the physiology of the brain in ways that reflect reduced arousal.

SIGNIFICANCE

Understanding neural and cognitive changes associated with sleep loss may lead to important advancements in identifying and preventing potentially dangerous sleep-related lapses in vigilance.

Survival motor neuron protein deficiency alters microglia reactivity

Survival motor neuron (SMN) protein deficiency results in loss of alpha motor neurons and subsequent muscle atrophy in patients with spinal muscular atrophy (SMA). Reactive microglia have been reported in SMA mice and depleting microglia rescues the number of proprioceptive synapses, suggesting a role in SMA pathology. Here, we explore the contribution of lymphocytes on microglia reactivity in SMA mice and investigate how SMN deficiency alters the reactive profile of human induced pluripotent stem cell (iPSC)-derived microglia. We show that microglia adopt a reactive morphology in spinal cords of SMA mice. Ablating lymphocytes did not alter the reactive morphology of SMA microglia and did not improve the survival or motor function of SMA mice, indicating limited impact of peripheral immune cells on the SMA phenotype. We found iPSC-derived SMA microglia adopted an amoeboid morphology and displayed a reactive transcriptome profile, increased cell migration, and enhanced phagocytic activity. Importantly, cell morphology and electrophysiological properties of motor neurons were altered when they were incubated with conditioned media from SMA microglia. Together, these data reveal that SMN-deficient microglia adopt a reactive profile and exhibit an exaggerated inflammatory response with potential impact on SMA neuropathology.

Dystonin loss-of-function leads to impaired autophagosome-endolysosome pathway dynamics

The neuronal dystonin protein (DST-a) is a large cytoskeletal linker important for integrating the various components of the cytoskeleton. Recessive Dst mutations lead to a sensory neuropathy in mice, known as dystonia musculorum (Dst^dt). The disease is characterized by ataxia, autonomic disturbances, and ultimately, death, which are associated with massive degeneration of the sensory neurons in the dorsal root ganglion (DRG). Recent investigation of Dst^dt sensory neurons revealed an accumulation of autophagosomes and a disruption in autophagic flux, which was believed to be due to insufficient availability of motor protein. Motor protein levels and the endolysosomal pathway were assessed in pre-symptomatic (postnatal day 5; P5) and symptomatic (P15) stage wild-type and Dst^dt DRGs. Levels of mRNA encoding molecular motors were reduced, although no significant reduction in the protein level was detected. An increase in lysosomal marker LAMP1 in medium-large size Dst^dt-27J sensory neurons was observed, along with an accumulation of electron-light single-membraned vesicles in Dst^dt-27J DRG tissue at the late stages of disease. These vesicles are likely to have been autolysosomes, and their presence in only late-stage Dst^dt-27J sensory neurons is suggestive of a pathological defect in autophagy. Further investigation is necessary to confirm vesicle identity, and to determine the role of Dst-a in normal autophagic flux.

Motor transmission defects with sex differences in a new mouse model of mild spinal muscular atrophy

Background

Mouse models of mild spinal muscular atrophy (SMA) have been extremely challenging to generate. This paucity of model systems has limited our understanding of pathophysiological events in milder forms of the disease and of the effect of SMN depletion during aging.

Methods

A mild mouse model of SMA, termed Smn^2B/−;SMN2^+/−, was generated by crossing Smn^−/−;SMN2 and Smn^2B/2B mice. This new model was characterized using behavioral testing, histology, western blot, muscle-nerve electrophysiology as well as ultrasonography to study classical SMA features and extra-neuronal involvement.

Findings

Smn^2B/−;SMN2^+/− mice have normal survival, mild but sustained motor weakness, denervation and neuronal/neuromuscular junction (NMJ) transmission defects, and neurogenic muscle atrophy that are more prominent in male mice. Increased centrally located nuclei, intrinsic contractile and relaxation muscle defects were also identified in both female and male mice, with some male predominance. There was an absence of extra-neuronal pathology.

Interpretation

The Smn^2B/−;SMN2^+/− mouse provides a model of mild SMA, displaying some hallmark features including reduced weight, sustained motor weakness, electrophysiological transmission deficit, NMJ defects, and muscle atrophy. Early and prominent increase central nucleation and intrinsic electrophysiological deficits demonstrate the potential role played by muscle in SMA disease. The use of this model will allow for the understanding of the most susceptible pathogenic molecular changes in motor neurons and muscles, investigation of the effects of SMN depletion in aging, sex differences and most importantly will provide guidance for the currently aging SMA patients treated with the recently approved genetic therapies.

Funding

: This work was supported by Cure SMA/Families of SMA Canada (grant numbers KOT-1819 and KOT-2021); Muscular Dystrophy Association (USA) (grant number 575466); and Canadian Institutes of Health Research (CIHR) (grant number PJT-156379).

Characterization of gastrointestinal pathologies in the dystonia musculorum mouse model for hereditary sensory and autonomic neuropathy type VI

BACKGROUND

Dystonia musculorum (Dst^dt ) is a murine disease caused by recessive mutations in the dystonin (Dst) gene. Loss of dorsal root ganglion (DRG) sensory neurons, ataxia, and dystonic postures before death by postnatal day 18 (P18) is a hallmark feature. Recently we observed gas accumulation and discoloration in the small intestine and cecum in Dst^dt mice by P15. The human disease resulting from dystonin loss-of-function, known as hereditary sensory and autonomic neuropathy type VI (HSAN-VI), has also been associated with gastrointestinal (GI) symptoms including chronic diarrhea and abdominal pain. As neuronal dystonin isoforms are expressed in the GI tract, we hypothesized that dystonin loss-of-function in Dst^dt-27J enteric nervous system (ENS) neurons resulted in neurodegeneration associated with the GI abnormalities.

METHODS

We characterized the nature of the GI abnormalities observed in Dst^dt mice through histological analysis of the gut, assessing the ENS for signs of neurodegeneration, evaluation of GI motility and absorption, and by profiling the microbiome.

KEY RESULTS

Though gut histology, ENS viability, and GI absorption were normal, slowed GI motility, thinning of the colon mucous layer, and reduced microbial richness/evenness were apparent in Dst^dt-27J mice by P15. Parasympathetic GI input showed signs of neurodegeneration, while sympathetic did not.

CONCLUSIONS & INFERENCES

Dst^dt-27J GI defects are not linked to ENS neurodegeneration, but are likely a result of an imbalance in autonomic control over the gut. Further characterization of HSAN-VI patient GI symptoms is necessary to determine potential treatments targeting symptom relief.

Driving safety improves after individualized training: An RCT involving older drivers in an urban area

Objective: This study aimed to reproduce the results of a previous investigation on the safety benefits of individualized training for older drivers. We modified our method to address validity and generalizability issues. Methods: Older drivers were randomly assigned to one of the 3 arms: (1) education alone, (2) education + on road training, and (3) education + on road + simulator training. Older drivers were recruited from a larger urban community. At the pre- and posttests (separated by 4 to 8 weeks) participants followed driving directions using a Global Positioning System (GPS) navigation system. Results: Our findings support the positive influence of individualized on-road training for urban-dwelling older drivers. Overall, driving safety improved among drivers who received on-road training over those who were only exposed to an education session, F(1, 40) = 11.66, P = .001 (26% reduction in total unsafe driving actions [UDAs]). Statistically significant improvements were observed on observation UDAs (e.g., scanning at intersections, etc.), compliance UDAs (e.g., incomplete stop), and procedural UDAs (e.g., position in lane). Conclusion: This study adds to the growing evidence base in support of individualized older driver training to optimize older drivers' safety and promote continued safe driving.

Dystonin-A3 upregulation is responsible for maintenance of tubulin acetylation in a less severe dystonia musculorum mouse model for hereditary sensory and autonomic neuropathy type VI

Hereditary sensory and autonomic neuropathy type VI (HSAN-VI) is a recessive human disease that arises from mutations in the dystonin gene (DST; also known as Bullous pemphigoid antigen 1 gene). A milder form of HSAN-VI was recently described, resulting from loss of a single dystonin isoform (DST-A2). Similarly, mutations in the mouse dystonin gene (Dst) result in severe sensory neuropathy, dystonia musculorum (Dstdt). Two Dstdt alleles, Dstdt-Tg4 and Dstdt-27J, differ in the severity of disease. The less severe Dstdt-Tg4 mice have disrupted expression of Dst-A1 and -A2 isoforms, while the more severe Dstdt-27J allele affects Dst-A1, -A2 and -A3 isoforms. As dystonin is a cytoskeletal-linker protein, we evaluated microtubule network integrity within sensory neurons from Dstdt-Tg4 and Dstdt-27J mice. There is a significant reduction in tubulin acetylation in Dstdt-27J indicative of microtubule instability and severe microtubule disorganization within sensory axons. However, Dstdt-Tg4 mice have no change in tubulin acetylation, and microtubule organization was only mildly impaired. Thus, microtubule instability is not central to initiation of Dstdt pathogenesis, though it may contribute to disease severity. Maintenance of microtubule stability in Dstdt-Tg4 dorsal root ganglia could be attributed to an upregulation in Dst-A3 expression as a compensation for the absence of Dst-A1 and -A2 in Dstdt-Tg4 sensory neurons. Indeed, knockdown of Dst-A3 in these neurons resulted in a decrease in tubulin acetylation. These findings shed light on the possible compensatory role of dystonin isoforms within HSAN-VI, which might explain the heterogeneity in symptoms within the reported forms of the disease.

Psychology of Computers: XIV. Cognitive Rehabilitation through Computer Games

The purpose of this study was to test the hypothesis that computer games may be an efficient therapeutic tool in a cognitive rehabilitation program. 60 subjects who showed attention difficulties with or without cerebral dysfunctions participated in a 12-hr. training program based on intensive use of a computer game. Analyses show improvement for the experimental group on scanning and tracking variables, notwithstanding the nature of their particular dysfunctions. Recommendations are presented regarding the nature and content of the cognitive tasks in a rehabilitation program.

Script Generation Following Frontal and Parietal Lesions

The purpose of this investigation was to distinguish putative effects of parietal lobe lesions on script generation, in distinction from the better known and established effects of frontal lobe lesions. Nine patients, most with excised parietal lesions, were compared to nine age, gender and education matched normal participants. Eleven patients with excised tumors of the frontal lobe were compared to twelve age, gender and education matched normal subjects. Participants were requested to generate, out loud, scripts corresponding to everyday activities. Half the scripts were relatively more demanding with respect to temporal representation (understanding the time line of events) and the other half with respect to spatial representation (understanding the layout of the actions in space). These two conditions were further broken down into conditions of high and low demands on working memory (reciting the scripts backwards versus forward). The frontal lobe patients enunciated significantly fewer actions overall. They were also significantly more impaired than the normal participants on all tasks with high demands on working memory, and more often, high temporal demands (sequencing and perseverative errors). The parietal lobe patients had significant difficulty in sequencing in all conditions, and manifested no perseveration. Though script generation tasks have been primarily associated with frontal lobe function until now, consideration should be given to the type of activity being scripted as a function of relative demands on spatial or temporal representation, as well as working memory, and the contributions of other lobes ought to be taken into consideration.

Purely axial compression of fiber Bragg gratings embedded in a highly deformable polymer

We demonstrate a tuning device for fiber Bragg gratings with a wavelength tuning range in excess of 65 nm. A purely axial tuning technique using a highly deformable polymer molded in a cylinder shape is used to embed a fiber Bragg grating and to achieve a wavelength tuning range from 1551.7 to 1485.5 nm. The tuning curve is highly linear with a tuning rate of 9.6 nm for every percent of applied strain. The insertion losses of the device, the variations of the full width at half maximum, and the stability of the Bragg wavelength over a working day have been studied and shown to be less than 0.02 dB, 0.14, and 0.2 nm, respectively.

Cognitive structure of executive deficits in patients with frontal lesions performing activities of daily living

OBJECTIVE

Executive function in activities of daily living (ADL) were investigated in 10 patients with excised frontal lobe tumours.

METHOD

The patients with frontal lesions were compared to 10 normal controls with a neuropsychological test battery, a script generation task and a realistic implementation of complex multi-task ADL (planning and preparing a meal).

RESULTS

The patients manifested numerous basic executive deficits on the paper-pencil tests, were unimpaired on the script generation task despite an aberrant semantic structure and manifested marked anomalies in the meal preparation task.

CONCLUSION

Frontal lobe deficits in lengthy complex multi-task ADL can be explained by impairment of several executive functions, generalized slowness of performance and paucity of behaviour.

Prenatal blockade of estradiol synthesis impairs respiratory and metabolic responses to hypoxia in newborn and adult rats

We tested the hypothesis that estradiol modifies respiratory control in pregnant rats and participates in the development of respiratory chemoreflexes in fetuses. Pregnant rats (n = 12) received daily subcutaneous injections of vehicle (Veh, n = 6) or 4-androsten-4-ol-3,17-dione acetate (ATD; inhibitor of estradiol synthesis; n = 6; 5 mg/day in vehicle) from gestational day 16 (G16) to delivery. Baseline ventilation (whole body plethysmography) and metabolic rate [oxygen consumption (Vo(2))] were determined at G14 and G20, in pups [on postnatal day 3 (P3) and P20] and in adult rats (on P70) born to Veh- or ATD-treated mothers. Hypoxic chemoreflex was assessed in P3 rats by acute exposure to 60% O(2) and in P20 or P70 rats by moderate hypoxia (12% O(2), 30 min). ATD treatment reduced circulating estradiol in pregnant dams at G20 without producing changes in the circulating level of estradiol precursors (testosterone and androstenedione). ATD-treated dams showed impaired respiratory adjustment to late gestation. Pups born to ATD mothers had higher resting Vo(2) (+23% at P3, +21% at P20), respiratory frequency (+15% at P3, +12% at P20), and minute ventilation (+11% at P3, +18% at P20) than pups from Veh mothers. Respiratory decrease during acute hyperoxic exposure at P3 was -9.7% in Veh (P < 0.05 vs. room air) and only -2.6% (P = not significant) in ATD pups. In P20 ATD rats, hypoxic ventilatory response was attenuated compared with Veh. In P20 and P70 rats, the drop of Vo(2) in hypoxia (-31% in P70, P < 0.0001) was not observed in ATD rats. We conclude that estradiol secreted during late gestation is necessary for respiratory adjustment to pregnancy and is required for adequate development of respiratory and metabolic control in the offspring.

Up-regulation of glutamate receptors is associated with LTP defects in the early stages of diabetes mellitus

AIMS/HYPOTHESIS

Recent studies involving electrophysiology and immunolabelling indicate that short-term insulin treatment of hippocampal neurons in culture induces changes in glutamate receptor function, suggesting that this receptor system can be altered on a relatively rapid time scale during diabetic conditions. To investigate this hypothesis, we examined whether brain glutamate receptors and long-term potentiation are altered in the early stages of diabetes mellitus in non-obese diabetic mice, a genetic model of Type I (insulin-dependent) diabetes mellitus.

METHODS

In vitro receptor autoradiography and immunoblotting were used to study the impact of diabetes on brain glutamate receptors. From an electrophysiological point of view, field potential recordings were also examined in area CA1 of hippocampal slices to determine the influence of diabetes on long-term potentiation.

RESULTS

Quantitative autoradiographic analysis revealed enhanced 3H-glutamate binding to several brain regions of diabetes mice, with maximal increases in the cerebral cortex and hippocampus. Saturation kinetics within the cerebral cortex disclosed that this change of 3H-glutamate was possibly due to an increase in the maximal number of N-methyl- D-aspartate binding sites, an interpretation that was corroborated by Western blot analysis of N-methyl- D-aspartate 2A subunits. Impairment in the expression of hippocampal long-term potentiation was also observed in diabetic mice, while the failure to elicit synaptic potentiation was prevented by insulin treatment.

CONCLUSION/INTERPRETATION

Because glutamate receptors are thought to be involved in several degenerative processes, our results suggest that up-regulation of these receptors in the early stages of diabetes could represent an important mechanism underlying neurological complications within the brain of diabetic patients.

Accounting for radioactivity before and after nebulization of tobramycin to insure accuracy of quantification of lung deposition

The ability to predict drug deposition of inhaled drugs used in cystic fibrosis (CF) is important if there is a need to target specific doses of drug to the lungs of individual patients. The gold standard of measuring pulmonary deposition is the quantification of an aerosolized radiolabel either mixed with the drug solution or tagged directly to the compound of interest. Accuracy of the quantification could be assured if there is agreement between the amount of radioactivity before and after administration. Before administration, the radiolabel is concentrated in the well of the nebulizer, whereas after administration, it is distributed throughout the nebulizer, the expiratory filter and connectors, and the upper airway, stomach, trachea, and lung. Not only is the geometry of the distribution that is presented to the gamma camera different, but there are different attenuation factors for the various body tissues. The primary aim of this study was to evaluate the accuracy of the quantification of deposition. Secondary goals were to compare in vitro nebulizer performance with that measured in vivo during the deposition study. Eighty milligrams of tobramycin and technetium bound to human serum albumin was administered to 10 normal adults using a Pari LC Jet Plus (Pari Respiratory Equipment, Inc., Richmond, VA) breath-enhanced nebulizer. Techniques were developed that allowed for the accounting of 99 +/- 2% of the initial radioactivity. The fraction of the rate of lung deposition to total body deposition was the in vivo respirable fraction (0.62 +/- 0.07), which closely agreed with in vitro measurements of respirable fraction (0.62 +/- 0.04). Drug output measured from the change in weight and concentration in the nebulizer systematically overestimated drug output measured by the deposition study. The results indicate that 11.8 of the initial 80 mg would be deposited in the lungs. This technique could be adapted to accurately quantify the amount of deposition on any inhaled therapeutic agent, but caution must be used when extrapolating performance of a nebulizer on the bench to expected deposition in patients.

[Lack of conviction about vaccination in certain Quebec vaccinators]

A questionnaire was mailed to all vaccinators in Quebec in 1998. The objective of this survey was to document vaccinators' attitudes, knowledge, and practices related to vaccination. Vaccinators generally believe in the security, efficacy and usefulness of vaccines given to young children. However, 41% of nurses do not fully agree with these opinions. More than 94% of pediatricians completely disagree that "certain practices (homeopathy, good eating habits and a healthy lifestyle) can eliminate the need for vaccination", compared with 85% of general practitioners and only 60% of nurses. Less than 25% of doctors recall children who are late in getting their immunizations; approximately 45% of vaccinators are in complete agreement with simultaneous injections of two vaccines; many circumstances are incorrectly seen as contra indications for vaccination. Public health authorities should target systematic interventions towards vaccinators to improve this situation and to increase nurses' conviction regarding the benefits of vaccination.

[Lack of conviction about vaccination in certain Quebec vaccinators]

A questionnaire was mailed to all vaccinators in Quebec in 1998. The objective of this survey was to document vaccinators' attitudes, knowledge, and practices related to vaccination. Vaccinators generally believe in the security, efficacy and usefulness of vaccines given to young children. However, 41% of nurses do not fully agree with these opinions. More than 94% of pediatricians completely disagree that "certain practices (homeopathy, good eating habits and a healthy lifestyle) can eliminate the need for vaccination", compared with 85% of general practitioners and only 60% of nurses. Less than 25% of doctors recall children who are late in getting their immunizations; approximately 45% of vaccinators are in complete agreement with simultaneous injections of two vaccines; many circumstances are incorrectly seen as contra indications for vaccination. Public health authorities should target systematic interventions towards vaccinators to improve this situation and to increase nurses' conviction regarding the benefits of vaccination.

Characterization of cytohesin-1 monoclonal antibodies: expression in neutrophils and during granulocytic maturation of HL-60 cells

ADP-ribosylation factors (Arf) are small GTP-binding proteins involved in vesicular transport and the activation of phospholipase D (PLD). The conversion of Arf-GDP to Arf-GTP is promoted in vivo by guanine nucleotide exchange factors such as ARNO or cytohesin-1. In order to examine the expression of ARNO and cytohesin-1 in human granulocytes, we generated specific polyclonal and monoclonal antibodies (mAbs). We also overexpressed GFP-ARNO and GFP-cytohesin-1 in RBL-2H3 cells to characterize the specificity and the ability of cytohesin-1 mAbs to immunoprecipitate cytohesin-1. Among the hybridomas secreting cytohesin-1 mAbs, only the clones 2E11, 1E4, 3C8, 6F5, 4C7, 7A3 and 8F7 were found to be specific for cytohesin-1. Furthermore, mAb 2E11 immunoprecipitated GFP-cytohesin-1 but not GFP-ARNO under native conditions. In contrast, mAbs 5D8, 4C3, 2G8, 6G11, 4C3, 6D4, 7B4 and 6F8 detected both cytohesin-1 and ARNO as monitored by immunoblotting. Although mAb 6G11 detected both proteins, this antibody immunoprecipitated GFP-ARNO but not GFP-cytohesin-1 under native conditions. Another antibody, mAb 10A12, also selectively immunoprecipitated GFP-ARNO under native conditions, but the epitope recognized by this mAb is unlikely to be linear as no signal was obtained by immunoblotting. Immunoprecipitation with a cytohesin-1 polyclonal antibody and blotting with cytohesin-1 specific mAbs revealed that cytohesin-1 is highly expressed in neutrophils. Cytohesin-1 can be detected in HL-60 cells but the endogenous protein levels were low in undifferentiated cells. Using the specific cytohesin-1 mAb 2E11 we observed a marked increase in levels of cytohesin-1 expression during dibutyryl-cyclic AMP-induced granulocytic differentiation of HL-60 cells. These data suggest that cytohesin-1, which may have important functions in neutrophil physiology, can be useful as a potential marker for granulocytic differentiation.

The role of human papillomavirus deoxyribonucleic acid assay and repeated cervical cytologic examination in the detection of cervical intraepithelial neoplasia among human immunodeficiency virus-infected women. Cervical Disease Study Group of the American Foundation for AIDS Research Community Based Clinical Trials Network

OBJECTIVES

We sought to measure the characteristics of a quantitative human papillomavirus deoxyribonucleic acid assay and repeated cervical cytologic examination in screening for cervical intraepithelial neoplasia among human immunodeficiency virus-infected women.

STUDY DESIGN

Human immunodeficiency virus-infected women with screening CD4+ lymphocyte counts of < or = 500 cells/mm3 (n = 103) were examined by quantitative human papillomavirus deoxyribonucleic acid assay and serial cervical cytologic examination and by colposcopy with biopsy and endocervical curettage during the course of 1 year.

RESULTS

Quantitative measures of total human papillomavirus deoxyribonucleic acid and high-risk human papillomavirus deoxyribonucleic acid were strongly associated with any cervical intraepithelial neoplasia (P = .005) and high-grade cervical intraepithelial neoplasia (P = .0006), but they improved the sensitivity and negative predictive value of baseline screening only slightly when combined with cervical cytologic examination. Incident cervical intraepithelial neoplasia occurred frequently (20%) during 1 year of follow-up and was more common among human papillomavirus-infected women. Repeated cytologic examination identified 60% of women with new cervical intraepithelial neoplasia.

CONCLUSION

Human immunodeficiency virus-infected women with at least mild immunosuppression have a high incidence of cervical intraepithelial neoplasia, which warrants close follow-up. Those with high baseline human papillomavirus deoxyribonucleic acid levels may be at the highest risk for incident cervical intraepithelial neoplasia.

Efficacy and safety of iron sucrose for iron deficiency in patients with dialysis-associated anemia: North American clinical trial

Iron sucrose has been used to provide intravenous (IV) iron therapy to patients outside the United States for more than 50 years. In a multicenter North American clinical trial, we determined the efficacy and safety of iron sucrose therapy in patients with dialysis-associated anemia, evidence of iron deficiency, and below-target hemoglobin (Hgb) levels despite epoetin therapy. Evidence of iron deficiency included a transferrin saturation (Tsat) less than 20% and ferritin level less than 300 ng/mL, and below-target Hgb levels included values less than 11.0 g/dL. We administered iron sucrose in 10 doses, each administered undiluted as 100 mg IV push over 5 minutes, without a prior test dose. We assessed efficacy by determining the subsequent change in Hgb, Tsat, and ferritin values. We assessed safety by recording blood pressure and adverse events after iron sucrose injection and comparing results with those for the same patients during an observation control period. Results showed a significant increase in Hgb level that was first evident after three doses of iron sucrose and persisted at least 5 weeks after the 10th dose. Tsat and ferritin levels also increased significantly and remained elevated. In 77 enrolled patients, including those with previous iron dextran sensitivity, other drug allergies, or concurrent angiotensin-converting enzyme inhibitor use, we saw no serious adverse drug reactions and no change in intradialytic blood pressure associated with iron sucrose administration. We conclude that iron sucrose injection administered as 1,000 mg in 10 divided doses by IV push without a prior test dose is safe and effective for the treatment of iron deficiency in patients with dialysis-associated anemia.

Articaine hydrochloride: a study of the safety of a new amide local anesthetic

BACKGROUND

Articaine is an amide local anesthetic introduced clinically in Germany in 1976 and subsequently throughout Europe, Canada and, in 2000, the United States.

METHODS

The authors report on three identical single-dose, randomized, double-blind, parallel-group, active-controlled multicenter studies that were conducted to compare the safety and efficacy of articaine (4 percent with epinephrine 1:100,000) with that of lidocaine (2 percent with epinephrine 1:100,000).

RESULTS

A total of 1,325 subjects participated in these studies, 882 of whom received articaine 4 percent with epinephrine 1:100,000 and 443 of whom received lidocaine 2 percent with epinephrine 1:100,000. The overall incidence of adverse events in the combined studies was 22 percent for the articaine group and 20 percent for the lidocaine group. The most frequently reported adverse events in the articaine group, excluding postprocedural dental pain, were headache (4 percent), facial edema, infection, gingivitis and paresthesia (1 percent each). The incidence of these events was similar to that reported for subjects who received lidocaine. The adverse events most frequently reported as related to articaine use were paresthesia (0.9 percent), hypesthesia (0.7 percent), headache (0.55 percent), infection (0.45 percent), and rash and pain (0.3 percent each).

CONCLUSIONS

Articaine is a well-tolerated, safe and effective local anesthetic for use in clinical dentistry.

Spatial encoding of hidden objects in dogs (Canis familiaris)

The authors investigated the type of spatial information that controls domestic dogs' (Canis familiaris) search behavior in a situation in which they have to locate a spatial position where they saw an object move and disappear. In Experiments 1 and 2, the authors manipulated all local and global sources of allocentric spatial information surrounding the hiding location. The results revealed that dogs relied on an egocentric frame of reference. Experiment 3 showed that dogs also encoded allocentric information when egocentric information was irrelevant. The authors conclude that dogs simultaneously encode both egocentric and allocentric spatial information to locate a spatial position, but they primarily base their search behavior on an egocentric frame of reference. The authors discuss under which natural conditions dogs might use these 2 sources of spatial information and detail the nature of spatial egocentric information and the circumstances underlying its use by dogs.

Safety and efficacy of iron sucrose in patients sensitive to iron dextran: North American clinical trial

Sensitivity to iron dextran is a potent obstacle to maintaining optimum iron status in patients with dialysis-associated anemia. As part of the North American clinical trials for iron sucrose injection, we examined the effect of intravenous (IV) iron sucrose in 23 hemodialysis patients with documented sensitivity to iron dextran, ongoing epoetin alfa therapy, and below-target-range hemoglobin (Hgb) levels (<11.0 g/dL). We assigned patients to treatment groups according to whether reactions they had experienced to iron dextran were judged to be mild (n = 16; group A) or severe (n = 7; group B). We prospectively examined adverse events and vital signs after administering 100 mg of IV iron sucrose in each of 10 consecutive dialysis treatment sessions and compared results with those recorded in each of three consecutive dialysis sessions without iron treatment. We administered iron sucrose by IV push over 5 minutes to group A patients and by IV push over 5 minutes or IV infusion over 15 to 30 minutes to group B patients. We did not administer a test dose. Results showed no serious adverse drug reactions after a total of 223 doses of iron sucrose (184 doses by IV push, 39 doses by IV infusion). Intradialytic blood pressure changes after IV iron sucrose injection did not differ from those recorded during dialysis sessions without treatment. An increase in values for Hgb, hematocrit, transferrin saturation, and ferritin, coupled with no significant change in epoetin dose and a decrease in total iron-binding capacity, confirmed the efficacy of iron sucrose injection in managing anemia. We conclude that iron sucrose injection is safe and effective in the management of anemia in patients sensitive to iron dextran and can be administered without a test dose by IV push or infusion.

A comparison between articaine HCl and lidocaine HCl in pediatric dental patients

PURPOSE

Three identical single-dose, randomized, double-blind, parallel-group, active-controlled multicenter studies were conducted to compare the safety and efficacy of articaine HCl (4% with epinephrine 1:100,000) to that of lidocaine HCl (2% with epinephrine 1:100,000) in patients aged 4 years to 79 years, with subgroup analysis on subjects 4 to < 13 years.

METHODS

Fifty subjects under the age of 13 years were treated in the articaine group and 20 subjects under the age of 13 were treated with lidocaine. Subjects were randomized in a 2:1 ratio to receive articaine or lidocaine. Efficacy was determined on a gross scale immediately following the procedure by having both the subject and investigator rate the pain experienced by the subject during the procedure using a visual analog scale (VAS). Safety was evaluated by measuring vital signs before and after administration of anesthetic (1 and 5 minutes post-medication and at the end of the procedure) and by assessing adverse events throughout the study. Adverse events were elicited during telephone follow-up at 24 hours and 7 days after the procedure.

RESULTS

Pediatric patients received equal volumes, but higher mg/kg doses, of articaine than lidocaine during both simple and complex dental procedures. Pain ratings: Articaine: VAS (Visual Analogue Scale) scores (from 0 to 10 cm) by patients 4 to < 13 years of age were 0.5 for simple procedures and 1.1 for complex procedures, and average investigator scores were 0.4 and 0.6 for simple and complex procedures, respectively. Lidocaine: patients 0.7 (simple) and 2.3 (complex); investigators 0.3 (simple) and 2.8 (complex). Adverse events: No serious adverse events related to the articaine occurred. The only adverse event considered related to articaine was accidental lip injury in one patient.

CONCLUSIONS

VAS scores indicate that articaine is an effective local anesthetic in children and that articaine is as effective as lidocaine when measured on this gross scale. Articaine 4% with epinephrine 1:100,000 is a safe and effective local anesthetic for use in pediatric dentistry. Time to onset and duration of anesthesia are appropriate for clinical use and are comparable to those observed for other commercially available local anesthetics.

Efficacy of articaine: a new amide local anesthetic

BACKGROUND

The authors compared the safety and efficacy of 4 percent articaine with epinephrine 1:100,000 with 2 percent lidocaine with epinephrine 1:100,000.

METHODS

In three identical randomized, double-blind, multicenter trials, subjects 4 to 80 years of age received either 4 percent articaine with epinephrine 1:100,000 or 2 percent lidocaine with epinephrine 1:100,000 for simple or complex dental procedures. In each trial, the authors randomized the subjects in a 2:1 ratio to receive articaine or lidocaine. Efficacy was determined by both subject and investigator using a visual analog scale, or VAS. The authors used the Kruskal-Wallis test to analyze the data.

RESULTS

A total of 882 subjects received articaine, and 443 received lidocaine. The authors found no statistical differences between the groups (P = .05). They also compared drug volumes for both articaine and lidocaine groups (2.5 milliliters +/- 0.07 standard error of mean, or SEM, vs. 2.6 mL +/- 0.09 SEM for simple procedures and 4.2 mL +/- 0.15 SEM vs. 4.5 mL +/- 0.21 SEM for complex procedures). The procedures' durations were comparable for both the articaine and lidocaine groups. The authors found no statistical difference between the two treatment groups (P = .05) with respect to subject or investigator pain ratings using the VAS; the mean pain scores determined by both patients and investigators for all groups tested were less than 1.0.

CONCLUSIONS

The authors found that 4 percent articaine with epinephrine 1:100,000 was well-tolerated in 882 subjects. It also provided clinically effective pain relief during most dental procedures and had a time to onset and duration of anesthesia appropriate for clinical use and comparable to those observed for other commercially available local anesthetics.

CLINICAL IMPLICATIONS

Pain control is a major component of patient comfort and safety. Local anesthetics form the backbone of pain control techniques in dentistry. Four percent articaine with epinephrine is an amide local anesthetic that will meet the clinical requirements for pain control of most dental procedures in most patients.

A novel karyopherin-beta homolog is developmentally and hormonally regulated in fetal lung

To investigate molecular mechanisms of lung organogenesis, we used representational difference analysis to search for glucocorticoid-inducible genes in developing lung in a fetal rat model. Messenger RNA prepared from fetal and adult rat lung was used to prepare "representative amplicons." Adult-lung complementary DNA (cDNA) amplicons were used as "driver" in successive rounds of subtractive hybridization/amplification to isolate target fetal lung-specific cDNAs. A single clone, which was conserved and had near-perfect homology to eight human/rodent expressed sequence tags, was used as template for 5' and 3' rapid amplification of cDNA ends and SPICE (system for polymerase chain reaction amplification of cDNA ends) reactions to obtain the 3.6-kb cDNA, LGL2 (Genbank, AF 110195) encoding a deduced polypeptide (lgl2) of 963 amino acids. Northern analysis confirmed that LGL2 is differentially expressed in fetal lung (maximal during the pseudoglandular stage, gestational Days 14 to 16), induced by glucocorticoid, and enriched in epithelium relative to the mesenchyme. LGL2 was also detected in human fetal lung at gestational Week 16 as well as in human and rat fetal brain, heart, intestine, and kidney. We mapped LGL2 to chromosome 1p33-34.2. Comparison with sequences in the genome database identified lgl2 as a member of the karyopherin-beta family of nuclear import proteins, with greatest homology to transportin SR. Maximal expression of LGL2 in the pseudoglandular stage of development is coordinate with that of key transcription factors that regulate prominent signal transduction pathways in fetal lung organogenesis. We propose a role for lgl2 in nuclear import of transcription factors that regulate signal transduction during fetal lung development.

A novel developmentally regulated gene in lung mesenchyme: homology to a tumor-derived trypsin inhibitor

We used differential display-PCR (DD-PCR) to identify glucocorticoid-inducible genes that regulate lung development in late gestation. DD-PCR, a method to screen for differentially expressed genes, is based on a comparison of mRNAs isolated from a subset of two or more cell populations by analysis of RT-PCR products on DNA-sequencing gels. We isolated cDNA probes representing mRNAs expressed in primary cultures of rat lung fibroblasts, but not in epithelial cells, on fetal day 20. A day 20 glucocorticoid-treated fibroblast cDNA library was screened with a single probe to isolate the 3.1-kb cDNA late-gestation lung 1 (LGL1; GenBank accession no. AF109674) encoding a deduced polypeptide of 188 amino acids. Northern analysis confirmed that LGL1 is expressed in human, rat, and mouse fetal lungs, induced by glucocorticoid, developmentally regulated in fibroblasts but not detectable in epithelium. In situ hybridization confirmed LGL1 expression in the mesenchyme, but not in the epithelium, of fetal rat lung, kidney, and gut. The predicted LGL1 gene product (lgl1) showed 81% homology to P25TI, a polypeptide trypsin inhibitor recently identified in human glioblastoma and neuroblastoma cells but not detected in normal human tissues. Both lgl1 and P25TI belong to the CRISP family of cysteine-rich extracellular proteins. Trypsin is produced by both normal bronchial epithelial and lung adenocarcinoma cells. Although additional studies will be necessary to clearly establish a functional role for lgl1, we propose that lgl1 has a role in normal lung development that is likely to be via regulation of extracellular matrix degradation.

Glucocorticoid receptor mRNA and protein in fetal rat lung in vivo: modulation by glucocorticoid and androgen

Pulmonary glucocorticoid receptor (GR) is essential to timely preparation for the onset of breathing air at birth. We have previously used primary culture of late-gestation fetal rat lung cells to demonstrate differential regulation of GR by glucocorticoid depending on cell type. In this study, we hypothesized that the action of glucocorticoid on GR mRNA expression and protein elaboration in lung cells might be modulated by interactions present in vivo but not in primary culture. Given that male sex hormone (androgen) has an inhibitory effect on antenatal lung development, we also postulated that androgen would decrease antenatal lung GR. We report that antenatal maternal injection of the glucocorticoid dexamethasone (1 mg/kg) enhanced fetal lung cellular levels of GR mRNA and protein as assessed by in situ hybridization and immunocytochemistry (ICC), respectively. ICC was performed using polyclonal rabbit anti-human antibody that reacts with rat GR whether bound to ligand or not and does not interfere with GR binding to DNA. Levels of GR mRNA and protein were enhanced in cells throughout all areas of the lung tissue, suggesting that interactions occurring in intact tissue may override the previously reported direct inhibition by glucocorticoid of GR protein elaboration in isolated fetal rat lung epithelial cells. Furthermore, antenatal administration of the androgen 5alpha-dihydrotestosterone (0.2 mg/kg) reduced tissue levels of GR mRNA and protein, consistent with androgenic inhibition of antenatal lung development by decreasing GR. We conclude that glucocorticoids and androgens exert opposite effects on fetal lung GR.

Glucose treatment attenuates spatial learning and memory deficits of aged rats on tests of hippocampal function

Groups of old and young rats were administered three tests of spatial learning and memory that are known to be sensitive to hippocampal dysfunction: the radial arm maze (RAM), spatial non-matching-to-sample (SNMTS), and a spatial vs. local cue-preference task. Old rats performed worse than young rats on the RAM and SNMTS tasks; on the cue-preference task, young rats were biased to use spatial cues, whereas old rats exhibited strong preferences for distinct, local cues. Peripheral injections of glucose (100 mg/kg) improved performance by old rats on the RAM and SNMTS, which correlated with measures of glucose metabolism. Glucose treatment did not affect old rats performance on the cue-preference task. There was evidence that glucose-treatment improved performance of young rats in the RAM test, but not the other tests. The results extend the range of tasks on which glucose-induced cognitive enhancement has been demonstrated in aged rats, and provides further evidence that memory loss resulting from hippocampal dysfunction is especially amenable to glucose treatment.

Female gender hormones regulate mRNA levels and function of the rat lung epithelial Na channel

The epithelial Na channel (ENaC) plays a critical role in the active reabsorption of alveolar fluid at the time of birth or during pulmonary edema. Although rat (r) ENaC is regulated by glucocorticoids during fetal development, there are no data regarding the influence of gender hormones on ENaC expression or function. We report higher levels of mRNAs encoding the alpha-rENaC subunit or the cystic fibrosis transmembrane conductance regulator (CFTR) in the lungs of nonpregnant adult female relative to adult male Wistar rats. Combined, but not separate, administration of progesterone and 17 beta-estradiol increased mRNA levels encoding alpha-rENaC, gamma-rENaC, and CFTR within 24 h. We also found a dose-dependent increase in rENaC functional activity (as assessed by the amiloride-sensitive short-circuit current across primary monolayer cultures of alveolar epithelial cells mounted in Ussing chambers) after a 5-day incubation of cells in medium containing progesterone and 17 beta-estradiol. These findings suggest a gender-dependent influence on the lung's ability to recover from pulmonary edema and on the degree of airway fluid hydration in cystic fibrosis.

Cognitive and functional assessments of stroke patients: an analysis of their relation

OBJECTIVES

To improve the assessment of stroke patients for the purpose of designing rehabilitation treatments and predicting rehabilitation outcomes. Specific objectives included the evaluation of the power of functional scales to properly assess both physical and cognitive disabilities, and the evaluation of the relations between functional, neurological, physical, and cognitive assessments. The hypothesis was that the relations between different assessment types (eg, functional, neurological, etc) can be assessed by the relations between the results of these assessments when administered to stroke patients.

DESIGN

Sixty-six stroke patients were administered a series of tests including functional assessments (Functional Independence Measure, barthel Index, Rankin Functional Scale), neurological assessments (Canadian Neurological Scale, National Institute of Health Stroke Scale), physical assessments (Stages of Motor Recovery, Clinical Outcome Variables Scale), and cognitive assessments (Stroke Unit Mental Status Examination, Mini Mental State, Raven Matrices, Boston Naming Test).

RESULTS

Analysis of correlation coefficients revealed that the stronger relationships were observed between functional assessments and physical assessments, and between functional assessments and neurological assessments. Cognitive tests did not correlate highly with any of the functional tests used in this study. Three factors were extracted using factor analysis. They were interpreted as being a physical disability factor (50% of the variance), a cognitive disability factor (23% of the variance), and a dementia factor (12% of variance). Functional scales obtained higher loads on the physical disability factor only.

CONCLUSIONS

Considering that cognitive functions are frequently affected in stroke patients, cognitive impairment needs to be more seriously considered when describing and/or predicting a patient's level of independence. In brain injured patients, such as stroke patients, we suggest that the total score provided by standardized functional scales should be interpreted with care. We believe that rehabilitation outcome could be better predicted if the results of functional assessment were coupled with in-depth cognitive assessment.

Pharmacokinetic study of the interaction between rifampin and delavirdine mesylate

OBJECTIVE

To study the effect of rifampin (INN, rifampicin), a potent inducer of cytochrome P450, on the steady-state pharmacokinetics of delavirdine.

METHODS

Twelve patients who were positive for human immunodeficiency virus, with CD4 counts ranging from 110 to 483/mm3, were randomized to two groups and studied in parallel. Both the control group (n = 5) and the rifampin group (n = 7) received 400 mg delavirdine mesylate every 8 hours for 30 days; subjects in the rifampin group took a 600 mg once-daily dose of rifampin on days 16 through 30. Harvested plasma from serial blood samples collected after dosing on days 15, 16, and 30 was assayed for delavirdine and its N-desalkyl metabolite concentrations with a reversed-phase HPLC method. Blood samples obtained on days 16 and 30 were also assayed for rifampin by HPLC.

RESULTS

Delavirdine mesylate alone and in combination with rifampin was well tolerated. On day 30, statistically significant differences between groups were observed for all delavirdine pharmacokinetic parameters (p < 0.049). In the rifampin group, delavirdine oral clearance increased by about 27-fold (p = 0.022), resulting in virtually negligible (< 0.09 mumol/L) steady-state through drug concentrations in all patients after 2 weeks of concurrent dosing of delavirdine mesylate and rifampin. The ratio of metabolite formation to elimination clearance for desalkyldelavirdine was significantly higher (3.9 +/- 1.2 versus 0.23 +/- 0.10) and delavirdine elimination half-life was significantly shorter (1.7 +/- 1.4 versus 4.3 +/- 1.3 hours) when delavirdine mesylate was taken with rifampin. Rifampin pharmacokinetic parameters on days 16 and 30 were similar to those previously reported for normal volunteers.

CONCLUSIONS

The findings of this study indicate that rifampin induces the metabolism of delavirdine. Therefore therapy with rifampin is contraindicated in patients receiving delavirdine mesylate.

Sex hormones regulate CFTR in developing fetal rat lung epithelial cells

Sex hormones modulate two normal processes of late-gestation mammalian lung development: the onset of augmented production of surfactant phospholipids and the loss of mesenchymal cells. As prenatal lung development advances, epithelial chloride secretory pathways diminish as opposing sodium absorptive pathways increase in expression. We hypothesized that sex hormones may influence both the gene expression and functional activity of the chloride channel known as the cystic fibrosis transmembrane conductance regulator (CFTR) in fetal lung epithelium. We report here that sex hormones exert opposite effects on CFTR. Androgen increases and estrogen decreases CFTR functional activity [as assessed by CFTR antisense (but not sense) oligodeoxynucleotide-sensitive adenosine 3',5'-cyclic monophosphate-stimulated cell volume reduction or by glibenclamide-sensitive, amiloride-insensitive transepithelial electrical potential] in primary cultures of fetal rat lung epithelial cells. No alterations in CFTR mRNA levels measured by quantitative polymerase chain reaction amplification of reverse transcripts) accompanied either the changes in functional activity induced by sex hormones or the changes observed during normal development, suggesting that sex hormone modulation of CFTR in antenatal lung occurs at a posttranscriptional level. Our data are consistent with the hypothesis that both androgen and estrogen contribute to the male disadvantage with respect to fetal lung functional development.

Progesterone and estradiol inhibit CFTR-mediated ion transport by pancreatic epithelial cells

The cystic fibrosis (CF), gene product, CF transmembrane conductance regulator (CFTR), is responsible for adenosine 3',5'-cyclic monophosphate (cAMP)-activated Cl- transport in epithelial cells, and mutant CFTR accounts for the pathology in the CF pancreas. We have previously shown that both isolated rabbit pancreatic acini and the human pancreatic duct cell line PANC-1 possess a cAMP-activated Cl- conductance identified as CFTR. We report here that preincubation in either of the female hormones progesterone or beta-estradiol inhibits activation by cAMP, but not by Ca2+ ionophore, of PANC-1 cell volume reduction under isotonic conditions. cAMP-activated cell volume reduction is sensitive to antisense, but not sense, CFTR oligodeoxynucleotide. Furthermore, progesterone inhibits cAMP-activated Cl- efflux from rabbit acinar cells. Moreover preincubation with progesterone, but not beta-estradiol, reduces CFTR mRNA and protein levels as measured using polymerase chain reaction amplification of reverse-transcribed acinar RNA and Western blots of protein from acinar membranes. We conclude that female hormones inhibit CFTR functional activity in pancreatic epithelial cells by different mechanisms.

Axonal arborizations of corticostriatal and corticothalamic fibers arising from the second somatosensory area in the rat

Corticostriatal and corticothalamic projections arising from the second somatosensory area in the rat were studied after labeling small pools of neurons in laminae V and VI with biocytin. Tracing the axon of single neurons revealed the following principles of organization: (i) all corticostriatal and corticothalamic projections arising from layer V cells are collaterals of long-range corticofugal axons that also project below the thalamic level; (ii) all layer V cells that project to the thalamus also project to the striatum; (iii) all layer VI corticothalamic cells project exclusively to the thalamus; (iv) cells of the upper part of lamina VI send collaterals to the thalamic reticular nucleus and arborize in the ventrobasal complex forming rod-like terminal fields; and (v) cells of the lower part of lamina VI also send collaterals to the thalamic reticular nucleus, give off few branches in the ventrobasal complex and terminate principally in the caudal part of the posterior thalamic group. On the basis of these findings, and in the light of previous anatomical studies, it is proposed that the above mentioned organizing principles represent general rules that also apply to corticostriatal and corticothalamic pathways arising from other areas of the neocortex.

Secondary structures and features of the 18S, 5.8S and 26S ribosomal RNAs from the Apicomplexan parasite Toxoplasma gondii

The two major subunits of the ribosomal RNA (rRNA) of Toxoplasma gondii, 18S and 26S, as well as 5.8S, have been sequenced and folded according to known consensus and established secondary structures. Conserved and variable nucleotide (nt) regions were identified using multiple alignments with rRNA sequences of selected organisms. The 18S rRNA showed a well conserved core structure of 48 stems and a hypervariable V4 region identified four additional stems including a pseudoknot. The 18S rRNA contained an additional helix in the V2 region located between nt 204 to 258. We noted that T. gondii 18S does not have a true V6 region, but was organized as a motif of a simple stem. T. gondii 26S had a conserved core structure of 83 stems and its expansion segments, so-called divergent domains, demonstrated a high degree of similarity with secondary structures from rRNA of dinoflagellates and ciliates. For the T. gondii 26S sequence, we found two additional stems, D3d and D3e, composed of 140 nt having a higher deltaG value. These segments are absent from the prokaryotic rRNA structures, whereas the hypervariable V4 region of the small subunit is not as variable. The well preserved structures could indicate an additional function for the eukaryotic ribosome.

Toxoplasma gondii: structure and characterization of the 26S ribosomal RNA and peptidyl transferase domain

The 26S, 5.8S, and the intergenic spacer ribosomal DNAs (rDNA) of Toxoplasma gondii have been cloned and completely sequenced from both DNA strands. The length of the large subunit was found to be 3487 nucleotides and the 5.8S was 153 nucleotides long. These formed the large rRNA subunit of Toxoplasma and were mapped in the rDNA unit known to be repeated 110 times in a head-to-tail fashion in the genome. Primer extension analysis and multiple alignments localized the 5' end point of the two rRNAs. Comparisons with Toxoplasma rDNA by nucleic acid homology studies gave 76% similarity with the dinoflagellate Prorocentrum micans, 66% with yeast Saccharomyces cerevisiae, and 64% with the ciliate Tetrahymena thermophila. Similarity was apparent in the conserved core structure of the large subunit rRNA and divergent sequences were identified in the so-called divergent domains. Construction of a secondary structure model of the peptidyl transferase center of the large rRNA revealed similarities with the same domain from other life forms.

Corticostriatal projections from layer V cells in rat are collaterals of long-range corticofugal axons

Corticostriatal projections arising from the infragranular layers of the motor and second somatosensory cortices were studied in rats after labeling small pools of neurons with biocytin. Camera lucida reconstruction of 263 fibers arising from laminae V and VI revealed that all corticostriatal projections derive from collaterals of lamina V cells whose main axons descend into the cerebral peduncle. In contrast, lamina VI cells do not branch upon the striatum, but upon the thalamus. Together with the results obtained in previous tracing studies, the present data raise the possibility that no neuron is exclusively corticostriatal. We therefore propose that all corticostriatal projections are collaterals given off by the axons of two types of neurons: layer V cells whose main axon project to the brainstem and/or spinal cord, and layer III cells that project to the contralateral hemisphere.