The nature of the principal type 1 interferon-producing cells in human blood

Interferons (IFNs) are the most important cytokines in antiviral immune responses. "Natural IFN-producing cells" (IPCs) in human blood express CD4 and major histocompatibility complex class II proteins, but have not been isolated and further characterized because of their rarity, rapid apoptosis, and lack of lineage markers. Purified IPCs are here shown to be the CD4(+)CD11c- type 2 dendritic cell precursors (pDC2s), which produce 200 to 1000 times more IFN than other blood cells after microbial challenge. pDC2s are thus an effector cell type of the immune system, critical for antiviral and antitumor immune responses.

The mechanism of action of cyclosporin A and FK506

The immunosuppressants cyclosporin A (CsA), FK506, and rapamycin suppress the immune response by inhibiting evolutionary conserved signal transduction pathways. CsA, FK506, and rapamycin bind to their intracellular receptors, immunophilins, creating composite surfaces that block the activity of specific targets. For CsA/cyclophilin and FK506/FKBP the target is calcineurin. Because of the large surface area of interaction of the drug-immunophilin complex with calcineurin, FK506 and CsA have a specificity for their biologic targets that is equivalent to growth factor-receptor interactions. To date, all the therapeutic as well as toxic effects of these drugs have been shown to be due to inhibition of calcineurin. Inhibition of the action of calcineurin results in a complete block in the translocation of the cytosolic component of the nuclear factor of activated T cells (NF-AT), resulting in a failure to activate the genes regulated by the NF-AT transcription factor. These genes include those required for B-cell help such as interleukin (IL-4) and CD40 ligand as well as those necessary for T-cell proliferation such as IL-2. The purpose of this article is to illustrate the means by which these drugs produce immunosuppression.

The influence of parental practices on child promotive and preventive food consumption behaviors: a systematic review and meta-analysis

Background

The family is an important social context where children learn and adopt eating behaviors. Specifically, parents play the role of health promoters, role models, and educators in the lives of children, influencing their food cognitions and choices. This study attempts to systematically review empirical studies examining the influence of parents on child food consumption behavior in two contexts: one promotive in nature (e.g., healthy food), and the other preventive in nature (e.g., unhealthy food).

Methods

From a total of 6,448 titles extracted from Web of Science, ERIC, PsycINFO and PubMED, seventy eight studies met the inclusion criteria for a systematic review, while thirty seven articles contained requisite statistical information for meta-analysis. The parental variables extracted include active guidance/education, restrictive guidance/rule-making, availability, accessibility, modeling, pressure to eat, rewarding food consumption, rewarding with verbal praise, and using food as reward. The food consumption behaviors examined include fruits and vegetables consumption, sugar-sweetened beverages, and snack consumption.

Results

Results indicate that availability (Healthy: r = .24, p < .001; Unhealthy: r = .34, p < .001) and parental modeling effects (Healthy: r = .32, p < .001; Unhealthy: r = .35, p < .001) show the strongest associations with both healthy and unhealthy food consumption. In addition, the efficacy of some parenting practices might be dependent on the food consumption context and the age of the child. For healthy foods, active guidance/education might be more effective (r = .15, p < .001). For unhealthy foods, restrictive guidance/rule-making might be more effective (r = −.11, p < .01). For children 7 and older, restrictive guidance/rule-making could be more effective in preventing unhealthy eating (r = − .20, p < .05). For children 6 and younger, rewarding with verbal praise can be more effective in promoting healthy eating (r = .26, p < .001) and in preventing unhealthy eating (r = − .08, p < .01).

Conclusions

This study illustrates that a number of parental behaviors are strong correlates of child food consumption behavior. More importantly, this study highlights 3 main areas in parental influence of child food consumption that are understudied: (1) active guidance/education, (2) psychosocial mediators, and (3) moderating influence of general parenting styles.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0501-3) contains supplementary material, which is available to authorized users.

Cognitive effects of topiramate, gabapentin, and lamotrigine in healthy young adults

OBJECTIVE

To study the acute and steady-state cognitive effects of three new antiepileptic drugs (AEDs): gabapentin, lamotrigine, and topiramate.

BACKGROUND

Several newer antiepileptic medications approved recently by the Food and Drug Administration are gaining attention as efficacious alternatives to established AEDs. Greater tolerability with fewer side effects are reported in some. However, the potential cognitive effects of these newer AEDs have received limited attention.

METHODS

Healthy young adults randomized to either of the three drugs were administered tests of attention, psychomotor speed, language, memory, and mood at baseline (predrug), acute single-dose period, and after 2 and 4 weeks on the drug.

RESULTS

Compared with baseline, the topiramate group had selective, statistically significant declines on measures of attention and word fluency at acute doses, whereas the other two AED groups had no performance changes. At the 2- and 4-week test periods, only the topiramate subjects continued to display neurocognitive effects from drug administration.

CONCLUSIONS

Results demonstrate potential acute and steady-state adverse cognitive effects for topiramate, whereas minimal effects were displayed for either gabapentin or lamotrigine in young healthy adults.

Scientific discovery in the age of artificial intelligence

Artificial intelligence (AI) is being increasingly integrated into scientific discovery to augment and accelerate research, helping scientists to generate hypotheses, design experiments, collect and interpret large datasets, and gain insights that might not have been possible using traditional scientific methods alone. Here we examine breakthroughs over the past decade that include self-supervised learning, which allows models to be trained on vast amounts of unlabelled data, and geometric deep learning, which leverages knowledge about the structure of scientific data to enhance model accuracy and efficiency. Generative AI methods can create designs, such as small-molecule drugs and proteins, by analysing diverse data modalities, including images and sequences. We discuss how these methods can help scientists throughout the scientific process and the central issues that remain despite such advances. Both developers and users of AI toolsneed a better understanding of when such approaches need improvement, and challenges posed by poor data quality and stewardship remain. These issues cut across scientific disciplines and require developing foundational algorithmic approaches that can contribute to scientific understanding or acquire it autonomously, making them critical areas of focus for AI innovation.

Selective internal radiation therapy for nonresectable hepatocellular carcinoma with intraarterial infusion of 90yttrium microspheres

PURPOSE

To evaluate the efficacy of intraarterial 90yttrium (90Y) microspheres in nonresectable hepatocellular carcinoma (HCC).

METHODS AND MATERIALS

Patients with nonresectable HCC, but without extrahepatic disease, who also had lung shunting < 15% and tumor-to-normal ratio > or =2, as determined by simulation using (99m)technetium macroaggregated albumin, were entered into the study. The radiation dose delivered to the lungs, tumor, and normal liver was estimated by a partition model. 90Y microspheres were infused into the hepatic artery at the time of hepatic angiography or through an implanted arterial portacatheter under fluoroscopy. Repeated treatments were given for residual or recurrent tumor. Response to treatment was monitored by serum alpha-fetoprotein or ferritin levels, together with serial computed tomography.

RESULTS

Seventy-one patients, including 20 patients with postoperative recurrence, were initially treated with an activity of 0.8 to 5.0 Giga-Becquerel (GBq) (21.6-135.1 mCi) (median 3.0 GBq or 81.1 mCi) of 90Y microspheres. There was a 50% reduction in tumor volume in 19 (26.7%) patients after the first treatment. However, the overall objective response in terms of changes in alpha-fetoprotein levels was 89% [partial response (PR) 67%, complete response (CR) 22%] among the 46 patients with raised pretreatment levels. The serum ferritin level in the other 25 patients dropped by 34 to 99% after treatment. Treatment was repeated in 15 patients. The maximum number of treatments was 5 and the maximum total activity was 13.0 GBq (351.4 mCi), given in 3 treatments. The estimated radiation doses to the nontumorous liver ranged from 25 to 136 Gy (median 52 Gy) in the first treatment and the highest total radiation dose was estimated to be 324 Gy. For the tumors, the estimated radiation doses ranged from 83 to 748 Gy (median 225 Gy) in the initial treatment and the highest cumulative dose reached was 1580 Gy. The residual tumors were resected in 4 patients. Two of these had complete histological remission, but only occasional viable tumor cells were found in the necrotic centers of the tumors resected from the other 2 patients. The median survival of the 71 patients was 9.4 months (range 1.8 to 46.4 months). Treatment was well tolerated and there was no bone-marrow toxicity, or clinical evidence of radiation hepatitis or pneumonitis.

CONCLUSIONS

Selective internal radiation therapy using 90Y microspheres is effective for selected cases of nonresectable HCC and is well tolerated. The objective response rate in terms of drop in tumor marker levels is higher than that based on reduction in tumor volume shown by computed tomography. The nontumorous liver appears more tolerant to internal radiation than external beam radiation. Selective internal radiation treatment may convert nonresectable tumors to resectable ones.

Partition model for estimating radiation doses from yttrium-90 microspheres in treating hepatic tumours

A uniform distribution of yttrium-90 (90Y) microspheres throughout the entire liver has always been assumed for dose calculation in treating hepatic tumours. A simple mathematical model was formulated which allows estimation of the activities of a therapeutic dose of 90Y microspheres partitioned between the lungs, the tumour and the normal liver, and hence the radiation doses to them. The doses to the tumour and normal liver were verified by intra-operative direct beta-probing. The percentage of activity shunted to the lung and the tumour-to-normal tissue ratio (T/N) were obtained from gamma scintigraphy using technetium-99m-labelled macroaggregated albumin (MAA) which simulates the 90Y microspheres used in subsequent treatment. The intrahepatic activity was partitioned between the tumour and the normal liver based on the T/N and their masses determined from computerized tomography slices. The corresponding radiation doses were computed using the MIRD formula. The estimated radiation doses were correlated with the doses directly measured using a calibrated beta-probe at laparotomy by linear regression. The radiation doses to the tumour and the normal liver, estimated using the partition model, were close to that measured directly with coefficients of correlation for linear regression: 0.862 for the tumours and 0.804 for the normal liver compartment (P<0.001). The partition model permits a distinction between the radiation doses received by the tumour and the normal liver to be made and the doses thus estimated are close to the actual doses received. The optimal doses to the tumour and normal liver and hence the required quantity of 90Y microspheres to be administered can be easily predetermined.

Elevated tumour marker CA19-9: clinical interpretation and influence of obstructive jaundice

AIMS

The tumour marker CA19-9 has been promoted as a reliable test for the detection of pancreatobiliary malignancy, yet its diagnostic role remains poorly defined. In this study the clinical interpretation of a raised serum CA19-9 level has been evaluated, with particular reference to obstructive jaundice.

METHODS

One hundred and sixty-four patients with a CA19-9 level above 33 U/ml were studied. Serum CA19-9 was compared with clinical diagnosis and correlated with serum bilirubin level. In a subgroup of jaundiced patients (16 benign and 15 malignant cases), follow-up CA19-9 levels were determined 2 weeks after biliary drainage.

RESULTS

The median CA19-9 level was lower in benign cases (102 (IQR 50-264) U/ml) than those with pancreatobiliary tumours (910 (IQR 263-6170) U/ml; P<0.01), although the overlap was substantial. In benign jaundiced cases, a positive correlation was observed between bilirubin and CA19-9 elevation (R=0.41, P<0.01). Relief of jaundice was associated with a fall in CA19-9 level in all benign cases and in nine of the 15 with malignancy.

CONCLUSION

Confident discrimination between benign and malignant disease could not be made on the basis of a solitary elevated CA19-9 measurement. Hyperbilirubinaemia was associated with a further deterioration in specificity and caution is warranted when interpreting the results in jaundiced patients. Overall, only one half of patients with an elevated CA19-9 level ultimately proved to harbour a malignancy.

Approaching the biology of human parental attachment: brain imaging, oxytocin and coordinated assessments of mothers and fathers

Brain networks that govern parental response to infant signals have been studied with imaging techniques over the last 15 years. The complex interaction of thoughts and behaviors required for sensitive parenting enables the formation of each individual's first social bonds and critically shapes development. This review concentrates on magnetic resonance imaging experiments which directly examine the brain systems involved in parental responses to infant cues. First, we introduce themes in the literature on parental brain circuits studied to date. Next, we present a thorough chronological review of state-of-the-art fMRI studies that probe the parental brain with a range of baby audio and visual stimuli. We also highlight the putative role of oxytocin and effects of psychopathology, as well as the most recent work on the paternal brain. Taken together, a new model emerges in which we propose that cortico-limbic networks interact to support parental brain responses to infants. These include circuitry for arousal/salience/motivation/reward, reflexive/instrumental caring, emotion response/regulation and integrative/complex cognitive processing. Maternal sensitivity and the quality of caregiving behavior are likely determined by the responsiveness of these circuits during early parent-infant experiences. The function of these circuits is modifiable by current and early-life experiences, hormonal and other factors. Severe deviation from the range of normal function in these systems is particularly associated with (maternal) mental illnesses - commonly, depression and anxiety, but also schizophrenia and bipolar disorder. Finally, we discuss the limits and extent to which brain imaging may broaden our understanding of the parental brain given our current model. Developments in the understanding of the parental brain may have profound implications for long-term outcomes in families across risk, resilience and possible interventions. This article is part of a Special Issue entitled Oxytocin and Social Behav.

Impact of a diagnostic cerebrospinal fluid enterovirus polymerase chain reaction test on patient management

CONTEXT

Enterovirus (EV) infection, the most common cause of aseptic meningitis, can be rapidly diagnosed with an EV-specific reverse transcriptase polymerase chain reaction (EV-PCR) test. However, no studies have examined EV-PCR in a clinical context in which it is routinely used.

OBJECTIVE

To determine the impact of EV-PCR testing on diagnosis and clinical management of suspected aseptic meningitis cases.

DESIGN AND SETTING

Retrospective review of electronic medical records from a 220-bed tertiary care pediatric medical center in San Diego, Calif.

PATIENTS

A total of 276 pediatric patients for whom a diagnostic EV-PCR test was performed during the calendar year 1998.

MAIN OUTCOME MEASURES

Clinical parameters such as length of stay, medication use, and ancillary test use.

RESULTS

One hundred thirty-seven patients (49.6%) had a positive cerebrospinal fluid EV-PCR result. Enterovirus-positive patients with results available before hospital discharge (n=95) had significantly fewer ancillary tests performed (26% vs 72% with at least 1 test performed; P<.001), received intravenous antibiotics for less time (median, 2.0 vs 3.5 days; P<.001), and had shorter hospital stays (median, 42 vs 71.5 hours; P<.001) than EV-negative patients (n=92). A positive EV-PCR result was associated with more rapid hospital discharge (median EV-PCR-to-discharge time, 5.2 hours) compared with a negative result (median EV-PCR-to-discharge time, 27.4 hours; P<.001).

CONCLUSIONS

Our results suggest that a positive EV-PCR result may affect clinical decision making and can promote rapid discharge of patients, and that unnecessary diagnostic and therapeutic interventions can be reduced by use of EV-PCR testing. JAMA. 2000;283:2680-2685.

Treatment of inoperable hepatocellular carcinoma with intrahepatic arterial yttrium-90 microspheres: a phase I and II study

Eighteen patients with inoperable hepatocellular carcinoma (HCC) were treated with intrahepatic arterial yttrium-90 microspheres. All these patients showed a lung shunting below 15% and a tumour-to-normal ratio higher than 2 as determined by diagnostic technetium-99m macroaggregated albumin (Tc-MAA) gamma scintigraphy. The treatment was given through an arterial port placed during laparotomy. The radiation doses to the liver and tumour were determined intraoperatively with a beta probe and liquid scintillation counting of multiple liver biopsies. The treatment was well tolerated without major complications. In all patients the tumour marker fell to a level which ranged from 41% to 0.2% of the pretreatment level. Tumour regression was found to be dose related. Progressive or static disease occurred in a higher proportion of patients whose tumours received < 120 Gy (P = 0.005). Survival was better in those whose tumours received > 120 Gy (median survival = 55.9 weeks) than those whose tumours received lower doses (median survival = 26.2 weeks). This difference is statistically significant with P = 0.005. We conclude that yttrium-90 microsphere therapy is safe and that tumour response is dose related. A tumour dose of > 120 Gy is recommended.

Cytoplasmic regulation of tight-junction permeability: effect of plant cytokinins

The significance of the "leaky" tight junction might be understood better if cells of the epithelial monolayer possessed mechanisms to regulate molecular flow through the junction. To test this possibility, Necturus gallbladder, a representative leaky epithelium, was studied before, during, and after mucosal exposure to plant cytokinins and two other microfilament-active drugs, cytochalasin B and phalloidin. Concomitant with morphological changes in microfilaments, cytokinins induced rapid reversible increases in transepithelial resistance and potential difference (PD) and decreases in NaCl dilution potentials, with no change in the ratio of relative cell membrane resistances. Cytochalasin B (0.2-1.2 microM) and phalloidin (0.6-12.7 microM) caused similar changes in transepithelial resistance and PD. When the intramembranous structure of tight junctions was studied by freeze fracture, peak cytokinin-induced increments in transepithelial resistance were associated with more disorder in the strand meshwork resulting in a small increase in tight junction depth, but there was no evidence of de novo strand assembly. These studies suggest that permeability of the tight junction of Necturus gallbladder is subject to rapid reversible modulation, possibly under cytoskeletal control.

The DNA sequence and comparative analysis of human chromosome 20

The finished sequence of human chromosome 20 comprises 59,187,298 base pairs (bp) and represents 99.4% of the euchromatic DNA. A single contig of 26 megabases (Mb) spans the entire short arm, and five contigs separated by gaps totalling 320 kb span the long arm of this metacentric chromosome. An additional 234,339 bp of sequence has been determined within the pericentromeric region of the long arm. We annotated 727 genes and 168 pseudogenes in the sequence. About 64% of these genes have a 5' and a 3' untranslated region and a complete open reading frame. Comparative analysis of the sequence of chromosome 20 to whole-genome shotgun-sequence data of two other vertebrates, the mouse Mus musculus and the puffer fish Tetraodon nigroviridis, provides an independent measure of the efficiency of gene annotation, and indicates that this analysis may account for more than 95% of all coding exons and almost all genes.

Modulation of cerebral GABA by topiramate, lamotrigine, and gabapentin in healthy adults

BACKGROUND

Anticonvulsant drugs have multiple mechanisms of action. Recent in vivo MRS studies suggest that cerebral gamma-aminobutyric acid (GABA) increases occur with the administration of certain anticonvulsants in humans.

OBJECTIVE

To investigate the effect of topiramate, gabapentin, and lamotrigine on cerebral GABA concentrations in healthy volunteers and correlate the GABA concentrations with serum drug levels.

METHODS

Seventeen healthy adults were randomly assigned to receive topiramate, gabapentin, and lamotrigine and underwent GABA measurements using a 4.1-T magnet from a 13.5-mL volume over the occipital region. GABA concentrations and serum levels were measured at 3 and 6 hours following administration of an acute single dose of one of the drugs. Thereafter, drugs were titrated over 4 weeks to target doses, with GABA measurements performed at 2 and 4 weeks.

RESULTS

Cerebral GABA concentrations rose 70% in the acute phase compared with baseline for topiramate. GABA rose 48% at 6 hours with gabapentin but not with lamotrigine. With long-term dosing and once target doses were achieved at 4 weeks, significant elevations in GABA were observed compared with baseline for all three drugs (topiramate 46%, gabapentin 25%, lamotrigine 25%).

CONCLUSION

This study demonstrates that single doses of topiramate and gabapentin increase cerebral GABA concentrations acutely (hours) in healthy individuals, but all drugs at clinically utilized doses increase cerebral GABA at 4 weeks. These results suggest that the mechanisms of action of anticonvulsant drugs are more complex and are likely to be multiple in nature.

Longitudinal analysis of multiple indicators of health decline among spousal caregivers

The hazards for experiencing major health events were studied longitudinally among 150 spousal caregivers of Alzheimer's disease (AD) patients and 46 married control participants. Based on longitudinal assessments from one to six years, the hazards of reaching any of three health events (extended physical illness or disability > 1 month, unhealthy medical rating from a nurse interview, or hospitalization) were not significantly different in a group comparison of caregivers to controls (Cox proportional hazards assumption, p > .05). However, there was a trend [X2(1, N = 107) = 3.13, p = .08] for caregivers to have a greater hazard for serious illness. Among caregivers only, a greater hazard for reaching at least one of these health events was associated with providing more activities of daily living (ADL) assistance [X2(1, N = 125) = 3.83, p = .05] but not with problem behaviors of the AD patient (p > .05). These results suggest that providing extensive ADL assistance may have health implications for spousal AD caregivers, while caregiving, per se, does not. Furthermore, these physical health impacts of caregiving may be best characterized using multidimensional assessments. Contrary to our guiding hypothesis, caregivers encountering more problem behaviors of their AD spouse were less likely to be hospitalized, X2(1, N = 145) = 5.88, p = .02. This finding may reflect a reluctance by caregivers to schedule necessary medical care when their spouses are most problematic, and this may have further long-term health implications for caregivers.

Normal human IgD+IgM- germinal center B cells can express up to 80 mutations in the variable region of their IgD transcripts

Somatic hypermutation in immunoglobulin variable region genes occurs within germinal centers. Here, we describe a subset of germinal center dark zone centroblasts that express only sIgD and have accumulated up to 80 mutations per heavy chain variable region (IgVH delta gene). Over half of the hypermutated IgVH delta sequences were found to be clonally related. This level of mutation is not observed in either IgVH gamma transcripts from the same sample or IgVH delta transcripts from peripheral blood, suggesting that these cells neither undergo isotype switch nor mature into circulating memory B cells. Optimal growth of these cells in vitro depends on CD40 ligand, T cell cytokines, and a fibroblast stroma, a combination possibly mimicking the dark zone microenvironment. Our hypothesis is that these cells may be sequestered within germinal centers, where their somatic mutation machinery is triggered. The isolation of these hypermutated B cells may represent a critical step for studying both the biology and biochemistry of somatic hypermutation.

Comparison of ictal SPECT and interictal PET in the presurgical evaluation of temporal lobe epilepsy

We retrospectively compared ictal technetium 99m hexamethylpropyleneamineoxime single-photon emission computed tomography (SPECT) and interictal 18F-fluorodeoxyglucose positron emission tomography (PET) in 35 patients with well-lateralized temporal lobe epilepsy (TLE). Based on SPECT scans the two observers correctly lateralized seizure foci with certainty in 89% of patients; interobserver agreement was excellent. Both observers incorrectly lateralized the seizure focus on two SPECT scans; one error was explained by rapid electroencephalographic spread to the contralateral side and for the other patient, isotope was injected during a brief aura. Based on PET scans, observers correctly lateralized the foci with certainty in 63% and with lesser confidence in 83%; four incorrect lateralizations were made by one observer and none by the other. PET interobserver disagreement was explained by differences between observers in weighting the relative hypometabolism in medial and lateral temporal regions. The detection rate for PET was lower in the absence of structural imaging abnormalities (60 vs 87%). PET yielded correct lateralizations in the 2 patients for whom SPECT interpretation was difficult. We conclude that both ictal SPECT and interictal PET are sensitive methods for the lateralization of TLE, but SPECT can be interpreted with greater certainty and is more sensitive when magnetic resonance imaging findings are negative. False lateralization is rare with ictal SPECT and can be explained when interpreted in conjunction with electroclinical data. Both investigations have complementary roles when localization is difficult.

The formation of topographical maps in developing rat gastrocnemius muscle during synapse elimination

1. The rat lateral gastrocnemius muscle (LG) is a complex of four muscle compartments, each defined in terms of its unique innervation by a single primary nerve branch of the muscle nerve. A study has been made of the topographical distribution of motor units in the medial compartment of the LG (LGM) both before and after the loss of polyneuronal innervation that accompanies development. 2. Glycogen depletion methods showed that the distribution of single motor units depended on the rostro-caudal origins of their axons in the spinal cord: rostral axons possessed motor units almost exclusively confined to the medial half of the LGM; intermediate axons possessed motor units primarily in the intermediate and lateral part of the LGM; caudal axons possessed motor units that were not restricted to any particular part of the LGM. 3. Myosin ATPase staining showed that about 80% of the LGM consists of type II A fibres, whilst the remainder are type II B. Physiological determination of the contractile properties of motor units indicated two classes of units: those that were relatively fatigue resistant and did not show a sag property (like fast-twitch, fatigue-resistant fibres or FR) and those that were relatively fatigable and did show a sag property (like fast-twitch, fatigable fibres or FF). 4. Glycogen depletion was also used to determine the distribution of motor units in the LGM at 7 days post-natal, when most fibres still receive a polyneuronal innervation. The LGM primary nerve branch innervated a confined sub-volume of muscle fibres which is similar to the mature pattern. However, rostral axons possessed motor units that extended into the lateral half of the LGM, a position from which they are excluded in the adult. 5. These observations suggest that the axons of rostral and intermediate units form a topographical map within adult FR motor units (type II A fibres) in the LGM. The results suggest that competition between axon terminals for synaptic sites plays a role in the elimination of inappropriately positioned terminals and subsequent emergence of the topographical map.

Real-time imaging of neurons retrogradely and anterogradely labelled with calcium-sensitive dyes

Membrane-impermeant calcium indicator dyes were used to retrogradely label dorsal root ganglia, spinal motoneurons and interneurons in the spinal cord of the chick embryo. The dyes were also used to label anterogradely primary afferent axons in the spinal cord and synaptic endings in the ciliary ganglion. Labelled neurons were imaged using digital videomicroscopy. Motoneurons and dorsal root ganglion cells exhibited a frequency-dependent change in fluorescence during antidromic stimulation. Single antidromic stimuli resulted in fluorescence transients that could be resolved in individual cells in real time. In addition, fluorescence changes could be recorded in motoneurons during episodes of bursting generated by rhythmic synaptic inputs from premotor networks. Stimulus-induced fluorescence signals were also detected in axons and synaptic endings labelled anterogradely. Optical signals were largely abolished in the absence of extracellular calcium. The results show that calcium changes can now be measured in identified populations of neurons and presynaptic terminals. The strong dependence of these signals on impulse activity suggests that the technique will be useful for monitoring the activity of identified neuronal populations. The calcium-dependent fluorescence signal probably results from cytosolic dye derived from diffusion which may limit the technique to situations in which the dye can be applied close (< 1 cm) to cell bodies.

Retrospective analysis of the utility of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in pancreatic masses, using a 22-gauge or 25-gauge needle system: a multicenter experience

BACKGROUND AND STUDY AIMS

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is now performed routinely in many advanced endoscopy centers and has enhanced the ability to diagnose pancreatic masses. However, there is uncertainty about which needle size is optimal for EUS-FNA of pancreatic masses. We aimed to evaluate the performance of the 22-gauge and 25-gauge needles in obtaining cytologic diagnosis of pancreatic masses.

METHODS

All cases that were referred for EUS-FNA for pancreatic masses between February 2001 and June 2007 were reviewed, and patients who underwent EUS-FNA using the 22-gauge and 25-gauge needle system were identified. In patients who underwent surgery, operative histopathological findings were compared with the cytopathological findings from EUS-FNA.

RESULTS

A total of 842 patients with pancreatic masses detected on computed tomography (CT) and/or magnetic resonance imaging (MRI) and confirmed by EUS underwent EUS-FNA with the 22-gauge needle (n = 540) or the 25-gauge needle (n = 302). Results of EUS-FNA cytology findings were compared with the gold standard of surgical histopathological findings or long-term clinical follow-up. The sensitivity, specificity, PPV, and NPV of FNA were respectively 84%, 100%, 100%, and 73% [corrected] for the 22-gauge needle compared with 92%, 97%, 98%, and 87%, [corrected] respectively for the 25-gauge needle. No complications were noted in the 25-gauge needle group, compared with pancreatitis in 2% of the 22-gauge needle group.

CONCLUSIONS

This retrospective comparative study shows that EUS-FNA with a 25-gauge needle system is a safe and reliable method for tissue sampling in pancreatic masses. The system is more sensitive and has a slightly [corrected] higher NPV than the standard 22-gauge needle. Our study suggests that perhaps the smaller caliber FNA needle causes less trauma during EUS-FNA and hence less complications. Further studies including randomized trials are needed.

Ca2+ regulation of tight-junction permeability and structure in Necturus gallbladder

To explore the role of Ca2+ in tight-junction permeability, the Necturus gallbladder was exposed to varying Ca2+ concentrations and to the Ca2+ ionophore A23187 added to the mucosal side (1.9 X 10(-6) to 6.8 X 10(-5) M). Electrophysiological parameters measured in an Ussing-type chamber were correlated with tight-junction morphology revealed by freeze-fracture electron microscopy. In Ca2+-free bathing media, transepithelial resistance decreases and tight-junctional ultrastructure is fragmented. In 1.8 mM Ca2+ media, A23187 induces an initial drop in transepithelial resistance, followed by an increase in transepithelial resistance to a value 20% above base line. At peak response to A23187, NaCl diffusion potentials decrease. Freeze-fracture replicas reveal that the number of junctional strands increase pari passu with junctional depth. Both physiological and morphological changes were partially reversible. The initial decrease in transepithelial resistance coincided with a persistent hyperpolarization of the mucosal cell membrane potential difference and a decrease in the mucosal-to-serosal cell membrane resistance ratio. Thus A23187 alters both the transcellular and paracellular pathway, resulting in opposing effects on transepithelial resistance.

Sugar coordinately and differentially regulates growth- and stress-related gene expression via a complex signal transduction network and multiple control mechanisms

In plants, sugars are required to sustain growth and regulate gene expression. A large set of genes are either up- or down-regulated by sugars; however, whether there is a common mechanism and signal transduction pathway for differential and coordinated sugar regulation remain unclear. In the present study, the rice (Oryza sativa cv Tainan 5) cell culture was used as a model system to address this question. Sucrose and glucose both played dual functions in gene regulation as exemplified by the up-regulation of growth-related genes and down-regulation of stress-related genes. Sugar coordinately but differentially activated or repressed gene expression, and nuclear run-on transcription and mRNA half-life analyses revealed regulation of both the transcription rate and mRNA stability. Although coordinately regulated by sugars, these growth- and stress-related genes were up-regulated or down-regulated through hexokinase-dependent and/or hexokinase-independent pathways. We also found that the sugar signal transduction pathway may overlap the glycolytic pathway for gene repression. alpha-Amylase and the stress-related genes identified in this study were coordinately expressed under sugar starvation, suggesting a convergence of the nutritional and environmental stress signal transduction pathways. Together, our studies provide a new insight into the complex signal transduction network and mechanisms of sugar regulation of growth and stress-related genes in plants.

Parietal lobe epilepsy: clinical features and seizure localization by ictal SPECT

We studied clinical and ictal single-photon emission computed tomography (SPECT) features in 14 patients with parietal lobe epilepsy, nine of whom had structural parietal lobe lesions. Thirteen patients had simple partial seizures of somatosensory (eight), psychic (four), and motor (nine) types. Complex partial seizures (CPS) occurred in seven patients; six were psychoparetic (prominent staring, relative immobility) and one had hyperkinetic activity. Seizures lasted 7 to 110 seconds; 99mTc-HMPAO (hexamethylpropylene amine oxime) was injected ictally, 7 to 89 seconds from seizure onset and 0 to 74 seconds (mean, 21.0 +/- 24.4 seconds) before seizure termination. Ictal SPECT demonstrated focal areas of parietal hyperperfusion in all 14 cases and corresponded with sites of the structural lesions. Parietal hyperperfusion was anterior in eight, posterior in four, and diffuse in two. Quantitative analysis revealed increases in parietal side-to-side perfusion ratios on ictal compared with interictal scans of 11 to 51% (mean, 25.5 +/- 14.4%). Ictal SPECT localization correlated with two main clinical seizure patterns: an anterior syndrome characterized by sensorimotor manifestations and a posterior syndrome characterized by CPS of the psychoparetic type. Ictal SPECT is helpful for localization of parietal seizures. Parietal hyperperfusion is discrete and short-lived, demanding true ictal injections for diagnostic studies.