Homozygous and heterozygous disruptions of ANK3: at the crossroads of neurodevelopmental and psychiatric disorders

AnkyrinG, encoded by the ANK3 gene, is involved in neuronal development and signaling. It has previously been implicated in bipolar disorder and schizophrenia by association studies. Most recently, de novo missense mutations in this gene were identified in autistic patients. However, the causative nature of these mutations remained controversial. Here, we report inactivating mutations in the Ankyrin 3 (ANK3) gene in patients with severe cognitive deficits. In a patient with a borderline intelligence, severe attention deficit hyperactivity disorder (ADHD), autism and sleeping problems, all isoforms of the ANK3 gene, were disrupted by a balanced translocation. Furthermore, in a consanguineous family with moderate intellectual disability (ID), an ADHD-like phenotype and behavioral problems, we identified a homozygous truncating frameshift mutation in the longest isoform of the same gene, which represents the first reported familial mutation in the ANK3 gene. The causality of ANK3 mutations in the two families and the role of the gene in cognitive function were supported by memory defects in a Drosophila knockdown model. Thus we demonstrated that ANK3 plays a role in intellectual functioning. In addition, our findings support the suggested association of ANK3 with various neuropsychiatric disorders and illustrate the genetic and molecular relation between a wide range of neurodevelopmental disorders.

Youth with disabilities' perspectives of the environment and participation: a qualitative meta-synthesis

Meta-syntheses can enhance our knowledge regarding the impact of the environment on the participation of youth with disabilities and generate theoretical frameworks to inform policy and best practices. The purpose of this study was to describe school-aged youth with disabilities' perspectives regarding the impact of the environment and modifications on their participation. A meta-synthesis systematically integrates qualitative evidence from multiple studies. Six databases were searched and 1287 citations reviewed for inclusion by two independent raters; 15 qualitative articles were selected for inclusion. Two independent reviewers evaluated the quality of each study and coded the results section. Patterns between codes within and across articles were examined using a constant comparative approach. Environments may be more or less inclusive for youth with disabilities depending upon others' understanding of individual abilities and needs, youth involvement in decisions about accommodations, and quality of services and policies. Youth implemented strategies to negotiate environmental barriers and appraised the quality of their participation based on the extent to which they engaged alongside peers. This meta-synthesis generated a framework illustrating the relationship between the environment, modifications and participation, and provided a conceptualization of participation grounded in the lived experiences of youth with disabilities. Findings reveal gaps in current knowledge and highlight the importance of involving youth with disabilities in decision making.

Epigenetic regulation of learning and memory by Drosophila EHMT/G9a

The epigenetic modification of chromatin structure and its effect on complex neuronal processes like learning and memory is an emerging field in neuroscience. However, little is known about the "writers" of the neuronal epigenome and how they lay down the basis for proper cognition. Here, we have dissected the neuronal function of the Drosophila euchromatin histone methyltransferase (EHMT), a member of a conserved protein family that methylates histone 3 at lysine 9 (H3K9). EHMT is widely expressed in the nervous system and other tissues, yet EHMT mutant flies are viable. Neurodevelopmental and behavioral analyses identified EHMT as a regulator of peripheral dendrite development, larval locomotor behavior, non-associative learning, and courtship memory. The requirement for EHMT in memory was mapped to 7B-Gal4 positive cells, which are, in adult brains, predominantly mushroom body neurons. Moreover, memory was restored by EHMT re-expression during adulthood, indicating that cognitive defects are reversible in EHMT mutants. To uncover the underlying molecular mechanisms, we generated genome-wide H3K9 dimethylation profiles by ChIP-seq. Loss of H3K9 dimethylation in EHMT mutants occurs at 5% of the euchromatic genome and is enriched at the 5' and 3' ends of distinct classes of genes that control neuronal and behavioral processes that are corrupted in EHMT mutants. Our study identifies Drosophila EHMT as a key regulator of cognition that orchestrates an epigenetic program featuring classic learning and memory genes. Our findings are relevant to the pathophysiological mechanisms underlying Kleefstra Syndrome, a severe form of intellectual disability caused by mutations in human EHMT1, and have potential therapeutic implications. Our work thus provides novel insights into the epigenetic control of cognition in health and disease.

Disruption of the epigenetic code: an emerging mechanism in mental retardation

Mental retardation (MR) is a highly diverse group of cognitive disorders. Gene defects account for about half of all patients and mutations causative for impaired cognition have been identified in more than 400 genes. While there are numerous genetic defects underlying MR, a more limited number of pathways is emerging whose disruption appears to be shared by groups of MR genes. One of these common pathways is composed of MR genes that encode regulators of chromatin structure and of chromatin-mediated transcription regulation. Already more than 20 "epigenetic MR genes" have been identified and this number is likely to increase in the coming years when deep sequencing of exomes and genomes will become commonplace. Prominent examples of epigenetic MR genes include the methyl CpG-binding protein MECP2 and the CREB binding protein, CBP. Interestingly, several epigenetic MR proteins have been found to interact directly with one another or act together in complexes that regulate the local chromatin structure at target genes. Thus, it appears that the functions of individual epigenetic MR proteins converge onto similar biological processes that are crucial to neuronal processes. The next challenge will be to gain more insight into patterns of altered DNA methylation and histone modifications that are caused by epigenetic gene mutations and how these will disrupt the brain-specific expression of target genes. Such research may reveal that a wide variety of mutations in the genetic code result in a more limited number of disruptions to the epigenetic code. If so, this will provide a rationale for therapeutic strategies.

SLC29A3 gene is mutated in pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome and interacts with the insulin signaling pathway

Pigmented hypertrichotic dermatosis with insulin-dependent diabetes (PHID) syndrome is a recently described autosomal recessive disorder associated with predominantly antibody negative, insulin-dependent diabetes mellitus. In order to identify the genetic basis of PHID and study its relationship with glucose metabolism, we performed homozygosity mapping in five unrelated families followed by candidate gene sequencing. Five loss-of-function mutations were identified in the SLC29A3 gene which encodes a member of a highly conserved protein family that transports nucleosides, nucleobases and nucleoside analogue drugs, hENT3. We show that PHID is allelic with a related syndrome without diabetes mellitus, H syndrome. The interaction of SLC29A3 with insulin signaling pathways was then studied using an established model in Drosophila melanogaster. Ubiquitous knockdown of the Drosophila ortholog of hENT3, dENT1 is lethal under stringent conditions; whereas milder knockdown induced scutellar bristle phenotypes similar to those previously reported in the knockdown of the Drosophila ortholog of the Islet gene. A cellular growth assay showed a reduction of cell size/number which could be rescued or enhanced by manipulation of the Drosophila insulin receptor and its downstream signaling effectors, dPI3K and dAkt. In summary, inactivating mutations in SLC29A3 cause a syndromic form of insulin-dependent diabetes in humans and in Drosophila profoundly affect cell size/number through interactions with the insulin signaling pathway. These data suggest that further investigation of the role of SLC29A3 in glucose metabolism is a priority for diabetes research.

Calyculin-A improves chromosome condensation for cytogenetic analysis of blastomeres from bovine and murine eight-cell stage embryos

This study evaluated the serine/threonine phosphatase inhibitor calyculin-A for rapid, efficient induction of premature chromosome condensation (PCC) in blastomeres obtained from Day 3 bovine and Day 2 murine eight-cell stage embryos, and its potential for use in cytogenetic analysis. Experiment 1 tested calyculin-A duration (0, 60, 120, and 180min) to induce PCC in bovine blastomeres. More blastomeres that underwent PCC had chromosomes suitable for cytogenetic analysis if treated for 120 or 180min (P<0.005). Experiment 2 compared doses of calyculin-A (0, 10, 50, and 100nM) on bovine blastomeres; calyculin-A (50nM, 120min) induced PCC suitable for cytogenetic analysis in the greatest number of blastomeres when compared to other doses (52.5%; P<0.005). Effects of calyculin-A (50nM) on murine blastomeres at durations of 0, 60, 90, and 120min to induce PCC were tested in Experiment 3, with 90min inducing the highest frequency of condensed chromosomes suitable for cytogenetic analysis (34%; P<0.05). Finally, Experiment 4 evaluated calyculin-A treated bovine embryos under optimal conditions (50nM, 120min) for use in gender and cytogenetic analysis. Whole chromosome paint probes were successfully hybridized to chromosomes along with 4',6-diamidino-2-phenylindole dihydrochloride hydrate (DAPI) counterstaining, allowing detection of embryo gender (54% F:46% M) and ploidy of individual blastomeres within embryos (64% diploid:36% mixoploid embryos). In conclusion, we inferred that calyculin-A was useful for rapid induction of PCC, producing chromosome spreads suitable for cytogenetic analysis of blastomeres in G1 or G2/M phase of the cell cycle.

foxois required for resistance to amino acid starvation in Drosophila

The ability of an organism to alter its metabolism, growth, and reproductive capacity in response to fluctuations in food availability has likely been an important factor in the course of evolution. The insulin signalling pathway is an evolutionarily conserved mechanism used by metazoan animals to sense and respond to changes in nutrient intake. During conditions of starvation the level of circulating insulin is low. Under conditions of low insulin, the foxo family of transcription factors are activated. Studies in Drosophila suggest that Drosophila foxo may alter the transcriptional profile of cells to allow for maximum survival of the fly during starvation. We have tested this ability in transgenic flies containing a luciferase reporter gene under the control of foxo response elements. We show that foxo activity is increased during amino acid starvation and reduced in the presence of amino acids. In addition, we find that loss of function of foxo leads to reduced survival under conditions of amino acid starvation in both larvae and adult flies. These data provide direct evidence that foxo is activated during amino acid starvation and is critical for optimal survival under these conditions.

Heart failure among younger rheumatoid arthritis and Crohn's patients exposed to TNF-alpha antagonists

OBJECTIVES

New onset heart failure (HF) has been associated with the use of TNF-alpha antagonists etanercept and infliximab based upon spontaneous adverse event reports. HF clinical trials of these agents were stopped early due to futility or worsening of existing HF. A potential association between etanercept and infliximab and new onset HF has been studied minimally at a population level.

METHODS

Using administrative claims from a large U.S. health care organization, we identified rheumatoid arthritis (RA) and Crohn's disease (CD) patients receiving infliximab or etanercept (exposed), and comparator cohorts of RA and CD patients receiving non-biologic immunosuppressives (unexposed). We studied adults < 50 years to reduce potential confounding related to common age-related comorbidities. Based on abstracted medical records of suspected HF cases, a physician panel adjudicated cases as definite, possible or no HF.

RESULTS

Among 4018 RA and CD patients with mean duration follow-up of 18 months, 9 of 33 suspected HF cases (identified using claims data) were adjudicated as definite (n = 5) or possible (n = 4) HF. The relative risk of HF among TNF-alpha antagonist-treated RA and CD patients was 4.3 and 1.2, respectively (P = NS for both). The absolute difference in cumulative incidence of HF among infliximab or etanercept-exposed compared to unexposed patients was 3.4 and 0.3 cases per 1000 persons for RA and CD (P = NS), respectively, yielding a number needed to harm of 294 for RA and 3333 for CD.

CONCLUSION

We found only a small number of presumed HF cases (n = 9, or 0.2%) in a large population of relatively young RA and CD patients. Although there was an increased relative risk of incident, HF that was not statistically significant among those exposed to TNF-alpha antagonists compared to those unexposed, larger cohorts are needed to provide more precise risk estimates and permit adjustment for potential confounding.

Insulin-like growth factor (IGF) family genes are aberrantly expressed in bovine conceptuses produced in vitro or by nuclear transfer

Embryos produced through somatic cell nuclear transfer (NT) or in vitro production (IVP) are often associated with increased abortion and abnormalities thought to arise from disruptions in normal gene expression. The insulin-like growth factor (IGF) family has a major influence on embryonic, fetal and placental development; differences in IGF expression in NT- and IVP-derived embryos may account for embryonic losses during placental attachment. In the present study, expression of IGF-I, IGF-II, IGF-I receptor (IGF-IR), and IGF-IIR mRNAs was quantitated in Day 7 and 25 bovine embryos produced in vivo, by NT, IVP, or parthenogenesis, to further understand divergent changes occurring during development. Expression of the IGF-I gene was not detected in Day 7 blastocysts for any treatment. However, there were no differences (P>0.10) among Day 7 treatments in the amounts of IGF-IR, IGF-II, and IGF-IIR mRNA. For Day 25 conceptuses, there was higher expression of IGF-I mRNA for NT and IVP embryonic tissues than for in vivo embryonic tissues (P<0.05). Furthermore, embryonic tissues from NT-derived embryos had higher expression of IGF-II mRNA than IVP embryonic tissues (P<0.05). Placental expression of IGF-IIR mRNA was greater for NT-derived than in vivo-derived embryos (P<0.05). There were no differences in IGF-IR mRNA across all treatments and tissues (P>0.10). In conclusion, these differences in growth factor gene expression during early placental attachment and rapid embryonic growth may directly or indirectly contribute to increased losses and abnormalities in IVP- and NT-derived embryos.

Expression of Drosophila FOXO regulates growth and can phenocopy starvation

BACKGROUND

Components of the insulin signaling pathway are important regulators of growth. The FOXO (forkhead box, sub-group "O") transcription factors regulate cellular processes under conditions of low levels of insulin signaling. Studies in mammalian cell culture show that activation of FOXO transcription factors causes cell death or cell cycle arrest. The Caenorhabditis elegans homologue of FOXO, Daf-16, is required for the formation of dauer larvae in response to nutritional stress. In addition, FOXO factors have been implicated in stress resistance and longevity.

RESULTS

We have identified the Drosophila melanogaster homologue of FOXO (dFOXO), which is conserved in amino acid sequence compared with the mammalian FOXO homologues and Daf-16. Expression of dFOXO during early larval development causes inhibition of larval growth and alterations in feeding behavior. Inhibition of larval growth is reversible upon discontinuation of dFOXO expression. Expression of dFOXO during the third larval instar or at low levels during development leads to the generation of adults that are reduced in size. Analysis of the wings and eyes of these small flies indicates that the reduction in size is due to decreases in cell size and cell number. Overexpression of dFOXO in the developing eye leads to a characteristic phenotype with reductions in cell size and cell number. This phenotype can be rescued by co-expression of upstream insulin signaling components, dPI3K and dAkt, however, this rescue is not seen when FOXO is mutated to a constitutively active form.

CONCLUSIONS

dFOXO is conserved in both sequence and regulatory mechanisms when compared with other FOXO homologues. The establishment of Drosophila as a model for the study of FOXO transcription factors should prove beneficial to determining the biological role of these signaling molecules. The alterations in larval development seen upon overexpression of dFOXO closely mimic the phenotypic effects of starvation, suggesting a role for dFOXO in the response to nutritional adversity. This work has implications in the understanding of cancer and insulin related disorders, such as diabetes and obesity.

GAL4 causes developmental defects and apoptosis when expressed in the developing eye of Drosophila melanogaster

The UAS/GAL4 ectopic expression system is widely used in Drosophila melanogaster for the overexpression of transgenes. This system operates under the assumption that the yeast transcription factor, GAL4, is inactive in D. melanogaster. Thus, GAL4 can be expressed under the control of D. melanogaster -specific promoters with little effect upon the organism. We have shown that expression of GAL4 in the developing eye under the control of the glass multiple reporter (GMR) promoter element does have an effect on eye development. Although GMR-GAL4 heterozygotes appear normal when raised at 25 degrees C, the homozygotes have a highly disorganized ommatidial array. In addition, the levels of apoptosis in the third-instar larval eye imaginal disc (where GAL4 is expressed) are slightly higher in GMR-GAL4 heterozygotes, and much higher in GMR-GAL4 homozygotes when compared to wild type discs. The morphological eye defects caused by GMR-GAL4 are significantly enhanced when flies are raised at 29 degrees C (presumably due to the higher activity of GAL4 at this temperature); however, the levels of apoptosis appear to be similar at these two temperatures. Taken together, these data suggest that GAL4 can have adverse effects on D. melanogaster development, especially at high expression levels. In addition, GAL4 appears to induce apoptosis even in the absence of any visible morphological defects. Thus, despite the benefits of the UAS/GAL4 ectopic expression system, one must use caution in the design and interpretation of experiments.

Chronic exercise increases GAD gene expression in the caudal hypothalamus of spontaneously hypertensive rats

Previous studies have suggested that a gamma-amino-butyric acid (GABA) deficit in the caudal hypothalamus (CH) of the spontaneously hypertensive rat (SHR) contributes to elevated levels of arterial pressure. The purpose of this study was to examine if SHR that underwent exercise training demonstrated a blunted development of hypertension and greater levels of glutamic acid decarboxylase (GAD) mRNA transcripts in the caudal hypothalamus. SHR were randomly paired and assigned to either a trained group (T; n=9) or a non-trained control group (NT; n=9). Trained animals were exercised for 10 weeks on a motorized treadmill while NT animals concurrently rested on a mock-treadmill. Following the 10-week training period, Northern blot analyses of mRNA for both the 65-kDa (GAD(65)) and 67-kDa (GAD(67)) isoforms of GAD were performed on tissue from caudal hypothalamic and cerebellar control brain regions. Exercise training simultaneously blunted the developmental rise in blood pressure in SHR (Delta59+/-9 mmHg in trained versus Delta77+/-9 mmHg in non-trained; P<0.03) and increased both GAD(65) (147+/-44%) and GAD(67) (162+/-77%) mRNA transcript levels in the CH (P<0.05). In contrast, no difference was detected in GAD mRNA levels in the cerebellum between T and NT SHR. These findings are consistent with our previous functional studies and demonstrate that exercise can significantly and specifically upregulate GAD gene transcript levels in the caudal hypothalamus of hypertensive rats.

Cardiopulmonary function in rats with lung hemorrhage induced by pulsed ultrasound exposure

OBJECTIVE

To assess cardiopulmonary function in rats exposed to pulsed ultrasound using superthreshold exposure conditions known to produce significant lung hemorrhage.

METHODS

In 1 group of 9 anesthetized Sprague-Dawley rats, 5 foci of ultrasound-induced hemorrhage were produced in the left lung of each rat. In a second group of 6 rats, 5 foci of ultrasound-induced hemorrhage were produced in the left and right lungs of each rat. Each lesion was induced using superthreshold pulsed ultrasound exposure conditions (3.1-MHz center frequency, 1.7-kHz pulse repetition frequency, 1.3-micro-second pulse duration, 60-second exposure duration, 39-MPa in situ peak compressional pressure, and 17-MPa in situ peak rarefactional pressure). After exposure, the lungs were fixed in formalin and assessed histologically. The total lesion volume was calculated for each lesion in each lung lobe. Measurements of cardiopulmonary function included assessment of pulsatile arterial pressure, heart rate, end-tidal carbon dioxide, respiratory rate, and arterial blood gases (PCO2 and PO2). Functional data were quantified before (baseline) and 30 minutes after exposure to ultrasound.

RESULTS

In the 9 rats that had lesions in only the left lung, the mean (SEM) lesion volume was 97 (13) mm3 and represented about 3.4% of the total lung volume. In the 6 rats that had lesions in both the left and right lungs, the left, right, and total mean lesion volumes, respectively, were 102 (16), 114 (11), and 216 (18) mm3 and represented about 3.7%, 4.2%, and 7.9% of the total lung volume. There were no statistically significant differences in cardiopulmonary measurements between baseline values and values obtained after exposure to ultrasound in the 9 rats exposed on the left lung only. The 6 rats exposed bilaterally had statistically significant differences in arterial pressure (134 +/- 4 versus 113 +/- 9 mm Hg; P= .047) and arterial PO2 (70 +/- 5 versus 58 +/- 4 mm Hg; P = .024) between baseline values and values obtained after exposure to ultrasound.

CONCLUSIONS

The severity of ultrasound-induced lesions produced in 1 lung did not affect measurements of cardiopulmonary function because of the functional respiratory reserve in the unexposed lung. However, when both the left and right lungs had ultrasound-induced lesions, the functional respiratory reserve was decreased to a point at which rats were unable to maintain systemic arterial pressure or resting levels of arterial PO2.

Spontaneously hypertensive rats exhibit altered cardiovascular and neuronal responses to muscle contraction

We examined the cardiovascular and ventrolateral medullary neuronal responses to muscle contraction in the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto rat (WKY) control. Cardiovascular, respiratory and ventrolateral medullary neuronal responses to muscle contraction evoked by tibial nerve stimulation were recorded. SHRs exhibited significantly larger drops in arterial pressure compared to WKYs in response to muscle contraction (P < 0.05). Basal ventrolateral medulla neuronal discharge rates were similar between the SHR and the WKY groups. A majority of neurons recorded responded to muscle contraction in both the WKY (77 %; n = 53) and the SHR groups (68 %; n = 62). There was no difference in the percentage of neurons that responded with an increase (approximately 60 %) or decrease (approximately 40 %) in firing rate between hypertensive and normotensive rats. Pulse wave-triggered averaging techniques showed that most neurons that responded to muscle contraction also possessed a basal firing rhythm temporally related to the cardiac cycle (85 % in WKYs, 83 % in SHRs). However, decreases in neuronal firing rates in response to muscle contraction were significantly greater in SHRs than WKYs. Therefore, we conclude that muscle contraction unmasks a hyperexcitability of neurons in the ventrolateral medulla of SHRs that parallels the heightened blood pressure responses.

Disseminated vaccine strain varicella as the acquired immunodeficiency syndrome-defining illness in a previously undiagnosed child

The Food and Drug Administration licensed a live-virus varicella vaccine (Varivax; Merck & Co Inc, West Point, PA) in March 1995. Prelicensure adverse events were minimal; however, since licensure and increased vaccine use, rare previously undetected risks have arisen. Presented here is the clinical course of a previously undiagnosed, human immunodeficiency virus-infected boy who developed dissemination of the vaccine strain of varicella zoster after immunization. chickenpox, human immunodeficiency virus, pneumonia, encephalopathy, varicella vaccine, adverse events, dissemination.

Coinfection with Campylobacter species: an epidemiological problem?

AIMS

To determine the frequency of coinfection with multiple strains in sporadic cases of human Campylobacter infection.

METHOD AND RESULTS

During 1999 10 single colonies of Campylobacter were cultured from each of 53 positive faecal samples. Five isolates were taken from nonselective agar after passive filtration of faecal suspensions and five isolates were taken from selective agar plates. All isolates were sero- and phage typed and their antibiotic resistance determined. Pulsed-field gel electrophoresis and flagellin gene typing were performed on selected isolates. One patient was infected with Camp. coli, the remainder with strains of Camp. jejuni. The majority of patients was infected with a single strain of Campylobacter, but from each of four samples, 7.5%, two strains of Camp. jejuni, confirmed by molecular typing, were identified.

CONCLUSION

Coinfection occurs in sporadic cases of campylobacteriosis.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has implications in outbreak investigation when distinct strains have been isolated from epidemiologically related patients and/or the suspected source or vehicle.

Development of hypoxia-induced Fos expression in rat caudal hypothalamic neurons

The caudal hypothalamus is an important CNS site controlling cardiorespiratory integration during systemic hypoxia. Previous findings from this laboratory have identified caudal hypothalamic neurons of anesthetized rats that are stimulated during hypoxia. In addition, patch-clamp recordings in an in vitro brain slice preparation have revealed that there is an age-dependent response to hypoxia in caudal hypothalamic neurons. The present study utilized the expression of the transcription factor Fos as an indicator of neuronal depolarization to determine the hypoxic response of caudal hypothalamic neurons throughout postnatal development in conscious rats. Sprague-Dawley rats, aged three to 56 days, were placed in a normobaric chamber circulated with either 10% oxygen or room air for 3h. Following the hypoxic/normoxic exposure period, tissues from the caudal hypothalamus, periaqueductal gray, rostral ventrolateral medulla and nucleus tractus solitarius were processed immunocytochemically for the presence of the Fos protein. There was a significant increase in the density of neurons expressing Fos in the caudal hypothalamus of hypoxic compared to normoxic adult rats that was maintained in the absence of peripheral chemoreceptors. In contrast, no increase in the density of Fos-expressing caudal hypothalamic neurons was observed during hypoxia in rats less than 12 days old. Increases in Fos expression were also observed in an age-dependent manner in the periaqueductal gray, rostral ventrolateral medulla and nucleus tractus solitarius. These results show an increase in Fos expression in caudal hypothalamic neurons during hypoxia in conscious rats throughout development, supporting the earlier in vitro reports suggesting that these neurons are stimulated by hypoxia.

Chronic exercise alters caudal hypothalamic regulation of the cardiovascular system in hypertensive rats

Previous studies have documented a deficit in the GABA neurotransmitter system within the caudal hypothalamus (CH) of spontaneously hypertensive rats (SHR). The reduction in inhibitory influence on this cardiovascular excitatory brain region is associated with an increased neuronal activity and resting blood pressure. The purpose of this study was to determine if chronic treadmill and wheel-running activities alter the ability of the CH to regulate cardiovascular function. SHR were exercised on a treadmill (5 times/wk) at moderate intensity or allowed free access to running wheels (7 days/wk) for a period of 10 wk. Resting blood pressures were obtained before and after the exercise training periods. After the exercise period, rats were anesthetized and microinjection experiments were performed. Treadmill-trained SHR exhibited a significantly blunted developmental rise in resting blood pressure after 10 wk of exercise. A similar yet less marked effect was observed in wheel-run rats. Microinjection of the GABA synthesis inhibitor 3-mercaptopropionic acid (3-MP) into the CH of nonexercised SHR did not produce any change in arterial pressure. In contrast, microinjection of 3-MP into the CH produced significant increases in blood pressure and heart rate in exercised SHR. These results demonstrate that exercise training can alter CH cardiovascular regulation in hypertensive rats and therefore may play a role in increasing cardiovascular health.

Reflex cardiovascular responses originating in exercising muscles of mice

The cardiovascular responses induced by exercise are initiated by two primary mechanisms: central command and reflexes originating in exercising muscles. Although our understanding of cardiovascular responses to exercise in mice is progressing, a murine model of cardiovascular responses to muscle contraction has not been developed. Therefore, the purpose of this study was to characterize the cardiovascular responses to muscular contraction in anesthetized mice. The results of this study indicate that mice demonstrate significant increases in blood pressure (13.8 +/- 1.9 mmHg) and heart rate (33.5 +/- 11.9 beats/min) to muscle contraction in a contraction-intensity-dependent manner. Mice also demonstrate 23.1 +/- 3.5, 20.9 +/- 4.0, 21.7 +/- 2.6, and 25.8 +/- 3.0 mmHg increases in blood pressure to direct stimulation of tibial, peroneal, sural, and sciatic hindlimb somatic nerves, respectively. Systemic hypoxia (10% O(2)-90% N(2)) elicits increases in blood pressure (11.7 +/- 2.6 mmHg) and heart rate (42.7 +/- 13.9 beats/min), while increasing arterial pressure with phenylephrine decreases heart rate in a dose-dependent manner. The results from this study demonstrate the feasibility of using mice to study neural regulation of cardiovascular function during a variety of autonomic stimuli, including exercise-related drives such as muscle contraction.

The palm as a real-time wide-area data-access device

Handheld wireless technologies offer great promise in helping to improve healthcare. However, it is not clear whether off-the-shelf wireless networking will work as well within medical centers as this technology works outside of the medical center. Therefore, we evaluated the coverage of wide-area wireless technology within two representative academic medical centers. The study determined the rate of connectivity by testing both the Palm VII and the Minstrel V modem in a set of locations typically frequented by house staff in their daily activities. Within one hospital, connectivity was 59% for OmniSky service, and 78% for Palm.net. The second hospital's connectivity was over 93% with both devices. Differences in connectivity were likely due to the number of rooms visited with externally exposed walls, the suburban versus urban location of the academic medical center, and the relative location of service transponders. When examined by the Johns Hopkins Clinical Devices Laboratory, both devices were found to operate without interfering with other hospital equipment.

Papilin in development; a pericellular protein with a homology to the ADAMTS metalloproteinases

Papilin is an extracellular matrix glycoprotein that we have found to be involved in, (1) thin matrix layers during gastrulation, (2) matrix associated with wandering, phagocytic hemocytes, (3) basement membranes and (4) space-filling matrix during Drosophila development. Determination of its cDNA sequence led to the identification of Caenorhabditis and mammalian papilins. A distinctly conserved ‘papilin cassette’ of domains at the amino-end of papilins is also the carboxyl-end of the ADAMTS subgroup of secreted, matrix-associated metalloproteinases; this cassette contains one thrombospondin type 1 (TSR) domain, a specific cysteine-rich domain and several partial TSR domains. In vitro, papilin non-competitively inhibits procollagen N-proteinase, an ADAMTS metalloproteinase. Inhibiting papilin synthesis in Drosophila or Caenorhabditis causes defective cell arrangements and embryonic death. Ectopic expression of papilin in Drosophila causes lethal abnormalities in muscle, Malpighian tubule and trachea formation. We suggest that papilin influences cell rearrangements and may modulate metalloproteinases during organogenesis.

Campylobacter contamination of raw meat and poultry at retail sale: identification of multiple types and comparison with isolates from human infection

Campylobacter species are the major cause of acute bacterial enteritis reported in the United Kingdom, nonetheless many aspects of campylobacteriosis epidemiology remain poorly understood. The aim of this study was to determine the prevalence of Campylobacter jejuni and Campylobacter coli in fresh bovine, ovine, and porcine liver and chicken portions from retail outlets and compare strain subtype distributions with those associated with cases of human campylobacteriosis occurring within the same period and study area. Meat samples were examined by both enrichment culture and direct plating, and Campylobacter isolates were subjected to the same test procedures (identification, serotyping, phagetyping, resistotyping) applied to the clinical strains. Campylobacter species were isolated from 73.2% of 489 samples examined. Chicken exhibited the highest contamination rate (83.3%), followed by lamb (72.9%), pig (71.7%), and ox (54.2%) liver. C. jejuni predominated in chicken (77.3%), lamb (75.0%), and ox (49.0%) liver, and C. coli predominated in pigs' liver (42.4%). Campylobacter fetus was identified in 12.5% of ox liver samples and also in pig and lamb. Of the human isolates, 89.3% were C. jejuni and 10.7% C. coli. The greatest variation in C. jeuni subtypes was observed among the chicken isolates (57 sero/phage-types), followed by human (48 types) and lamb (30 types). A significant proportion of the chicken and lamb isolates shared identical subtypes with the human strains, indicative of their role as potential sources of infection. Almost 30% of samples yielded multiple strains of Campylobacter, a finding that reinforces the epidemiological importance of selecting and testing more than one presumptive isolate per sample.

Nidogen is nonessential and not required for normal type IV collagen localization in Caenorhabditis elegans

Nidogen (entactin) can form a ternary complex with type IV collagen and laminin and is thought to play a critical role in basement membrane assembly. We show that the Caenorhabditis elegans nidogen homologue nid-1 generates three isoforms that differ in numbers of rod domain endothelial growth factor repeats and are differentially expressed during development. NID-1 appears at the start of embryonic morphogenesis associated with muscle cells and subsequently accumulates on pharyngeal, intestinal, and gonad primordia. In larvae and adults NID-1 is detected in most basement membranes but accumulates most strongly around the nerve ring and developing gonad. NID-1 is concentrated under dense bodies, at the edges of muscle quadrants, and on the sublateral nerves that run under muscles. Two deletions in nid-1 were isolated: cg119 is a molecular null, whereas cg118 produces truncated NID-1 missing the G2 collagen IV binding domain. Neither deletion causes overt abnormal phenotypes, except for mildly reduced fecundity. Truncated cg118 NID-1 shows wild-type localization, demonstrating that the G2 domain is not necessary for nidogen assembly. Both nid-1 mutants assemble type IV collagen in a completely wild-type pattern, demonstrating that nidogen is not essential for type IV collagen assembly into basement membranes.

Hypothalamus, hypertension, and exercise

The hypothalamus is a well-known autonomic regulatory region of the brain involved in integrating several behaviors as well as cardiorespiratory activity. Our laboratory has shown that the caudal hypothalamus modulates the cardiorespiratory responses associated with exercise. In addition, other findings from this laboratory and others have implicated alterations in this same brain region in spontaneously hypertensive rats as contributing factors of the elevated levels of arterial pressure in hypertension. Several studies have revealed a gamma-amino-butyric acid (GABAergic) deficiency in the caudal hypothalamus of spontaneously hypertensive rats that contributes to the tonic disinhibition and overactivity of this pressor region. Because chronic exercise is able to increase cardiovascular health in the hypertensive rat, we hypothesized that exercise-induced caudal hypothalamic plasticity partially underlies the beneficial effects of physical activity. In this review we discuss initial findings from this lab that support this hypothesis. Our experiments demonstrate that chronic exercise alters gene expression and neuronal activity in the caudal hypothalamus of the spontaneously hypertensive rat. These findings describe a potential mechanism by which chronic exercise lowers blood pressure in the hypertensive individual.

Cuticle chirality and body handedness in Caenorhabditis elegans

Caenorhabditis elegans adult animals exhibit an inherent chirality of fiber orientation in the basal layer of the cuticle, as well as a naturally invariant but experimentally reversible handedness in the left-right (L-R) asymmetry of the body plan. We have examined the relationship between cuticle chirality and body handedness in normal and L-R reversed animals, using Roller (Rol) mutants and transmission electron microscopy to monitor cuticle properties. Rol phenotypes, several of which have been shown to result from mutations in cuticle collagen genes, are characterized by an invariant, allele-specific handedness in their direction of rolling. We show for several alleles that this direction is not affected by L-R reversal of the body plan. We further show, by electron microscopy, that the chiral orientation of cuticle fibers in animals with normal cuticle is not reversed by L-R body-plan reversal. We conclude that cuticle chirality must be established independently of body-plan handedness. The cues that establish cuticle chirality are still unknown, as are the causes for different rolling directions in different Roller mutants. We discuss the question of how cuticle chirality maintains its independence, and how the orientations of the fiber layers may be determined.