Mechanism of shortened action potential duration in Na+-Ca2+ exchanger knockout mice

In cardiac-specific Na(+)-Ca(2+) exchanger (NCX) knockout (KO) mice, the ventricular action potential (AP) is shortened. The shortening of the AP, as well as a decrease of the L-type Ca(2+) current (I(Ca)), provides a critical mechanism for the maintenance of Ca(2+) homeostasis and contractility in the absence of NCX (Pott C, Philipson KD, Goldhaber JI. Excitation-contraction coupling in Na(+)-Ca(2+) exchanger knockout mice: reduced transsarcolemmal Ca(2+) flux. Circ Res 97: 1288-1295, 2005). To investigate the mechanism that underlies the accelerated AP repolarization, we recorded the transient outward current (I(to)) in patch-clamped myocytes isolated from wild-type (WT) and NCX KO mice. Peak I(to) was increased by 78% and decay kinetics were slowed in KO vs. WT. Consistent with increased I(to), ECGs from KO mice exhibited shortened QT intervals. Expression of the I(to)-generating K(+) channel subunit Kv4.2 and the K(+) channel interacting protein was increased in KO. We used a computer model of the murine AP (Bondarenko VE, Szigeti GP, Bett GC, Kim SJ, and Rasmusson RL. Computer model of action potential of mouse ventricular myocytes. Am J Physiol Heart Circ Physiol 287: 1378-1403, 2004) to determine the relative contributions of increased I(to), reduced I(Ca), and reduced NCX current (I(NCX)) on the shape and kinetics of the AP. Reduction of I(Ca) and elimination of I(NCX) had relatively small effects on the duration of the AP in the computer model. In contrast, AP repolarization was substantially accelerated when I(to) was increased in the computer model. Thus, the increase in I(to), and not the reduction of I(Ca) or I(NCX), is likely to be the major mechanism of AP shortening in KO myocytes. The upregulation of I(to) may comprise an important regulatory mechanism to limit Ca(2+) influx via a reduction of AP duration, thus preventing Ca(2+) overload in situations of reduced myocyte Ca(2+) extrusion capacity.

Brachyury, a crucial regulator of notochordal development, is a novel biomarker for chordomas

Chordomas are malignant tumours that occur along the spine and are thought to derive from notochordal remnants. There is significant morphological variability between and within chordomas, with some showing prominent areas of chondroid differentiation. Our microarray data from a broad range of connective tissue neoplasms indicate that, at the transcriptional level, chordomas resemble cartilaginous neoplasms. Here we show that chordomas express many genes known to be involved in cartilage development, but they also uniquely express genes distinguishing them from chondroid neoplasms. The brachyury transcription factor, known to be involved in notochordal development, is only expressed by chordomas. Using a polyclonal antibody, we show that brachyury is expressed in the embryonic notochord and in all 53 chordomas analysed, labelling both chondroid and chordoid areas of these tumours. In contrast, the protein was not detected in over 300 neoplasms, including 163 chondroid tumours. Brachyury was not detected in the nucleus pulposus, arguing against the hypothesis that this tissue derives directly from the notochord. These data provide compelling evidence that chordomas derive from notochord and demonstrate that brachyury is a specific marker for the notochord and notochord-derived tumours.

The Life Tape Project, an existential intervention for cancer patients: A report on perceived benefits and changes in quality of life

8604

Background: Facing cancer, most patients struggle with mortality and threats to their emotional equilibrium and that of their families. Families may become closer, but often communication difficulties and isolation increase. The Life Tape Project (LTP) is an intervention—involving a two hour video-taped genealogy and life story in the presence of family—designed to help patients and families confront this existential crisis. An important aspect is the cultivation of Symbolic Immortality—that some important part of the person continues to exist symbolically, even after death—helping patients identify with things greater and more enduring than themselves, and providing a sense of what will remain with the family after they are gone. Observation and pilot data suggested patients receive substantial benefits from the LTP. Results from an ongoing study designed to quantify and extend these observations are reported. Method: Adults with any cancer diagnosis are recruited from the general population. Patients complete baseline questionnaires before the LT interview and follow-up packets two and ten weeks after. Measures include the FACT-G for Quality of Life (QOL) and a Perceived Benefits Questionnaire covering eight themes suggested by previous research. A final semi-structured interview probes for unwanted effects. Results: At first follow-up (N = 23 as of 1/8/06) repeated measure t-tests revealed significant increases in FACT-G Functional and QOL (Total) scales; and a majority of patients reported substantial benefits (endorsing “very” or “extremely true for me”) in at least one theme. Final interviews revealed no unwanted effects. Conclusions: The LTP is a powerful, safe, and accessible intervention that can improve family communication and connectedness, promote personal growth, and reduce existential anxiety through the creation of symbolic immortality. Requiring minimal equipment and time, it would make an excellent addition to any supportive care program.

[Table: see text]

No significant financial relationships to disclose.

Telehealth service delivery for persons with alcoholism

Videoconferencing at a bandwidth of 384 kbit/s was used in open sessions for subjects with alcohol use disorders (AUD). Study participants received eight sessions of group therapy over a four-week period from an accredited addictions counsellor. Outcome assessment included self-report measures, a qualitative interview and a chart review. Of the 18 subjects who started the study, 14 attended at least four sessions of therapy, completed self-report assessments and the thematic interview. The participants reported high levels of satisfaction with telepsychiatry, found the intervention to be highly credible, had good session attendance and attrition comparable to that expected with conventional same-room treatment. In all, 82% of subjects reported that they would recommend the service to a friend or family member. The results demonstrate the feasibility of using videoconferencing for service delivery to adults with AUD, and encourage the future performance of randomized controlled trials.

Does a Post-take Ward Round Proforma Lead to Sustainable Improvements in Quality of Documentation for Patients Admitted to the Medical Assessment Unit?

This study assessed the quality of post-take ward round (PTWR) documentation, specifically looking at twelve criteria, in the medical assessment unit (MAU) prior to, 3- months and 2-years after introducing a PTWR proforma. 216 case records were analysed; 40 prior to, 40 three-months and 146 two-years after introducing the PTWR proforma. There was a significant improvement in eight criteria threemonths after introducing the PTWR proforma. These improvements were sustained two-years later and significant improvements made in a further 3 criteria (1 at p < 0.05 and 2 at p ) 0.01).

Risk Factors for Delirium Tremens: A Retrospective Chart Review

A retrospective chart review was performed within an inpatient VA hospital setting in an attempt to identify risk factors for delirium tremens (DTs). Cases of delirium tremens were compared to cases where patients' alcohol withdrawal during hospitalization did not progress to DTs. Significant differences were found in regard to prior histories of DTs and laboratory values at admission. The amount and duration of benzodiazepine use during hospitalization, antipsychotic use during hospitalization, and length of hospitalization were also statistically different between the groups. While not reaching statistical significance, there were differences in reason for admission and relapse rate upon follow-up between the groups.

Proposal for molecular mechanism of thionins deduced from physico-chemical studies of plant toxins

We propose a molecular model for phospholipid membrane lysis by the ubiquitous plant toxins called thionins. Membrane lysis constitutes the first major effect exerted by these toxins that initiates a cascade of cytoplasmic events leading to cell death. X-ray crystallography, solution nuclear magnetic resonance (NMR) studies, small angle X-ray scattering and fluorescence spectroscopy provide evidence for the mechanism of membrane lysis. In the crystal structures of two thionins in the family, alpha(1)- and beta-purothionins (MW: approximately 4.8 kDa), a phosphate ion and a glycerol molecule are modeled bound to the protein. (31)P NMR experiments on the desalted toxins confirm phosphate-ion binding in solution. Evidence also comes from phospholipid partition experiments with radiolabeled toxins and with fluorescent phospholipids. This data permit a model of the phospholipid-protein complex to be built. Further, NMR experiments, one-dimensional (1D)- and two-dimensional (2D)-total correlation spectroscopy (TOCSY), carried out on the model compounds glycerol-3-phosphate (G3P) and short chain phospholipids, supported the predicted mode of phospholipid binding. The toxins' high positive charge, which renders them extremely soluble (>300 mg/mL), and the phospholipid-binding specificity suggest the toxin-membrane interaction is mediated by binding to patches of negatively charged phospholipids [phosphatidic acid (PA) or phosphatidyl serine (PS)] and their subsequent withdrawal. The formation of proteolipid complexes causes solubilization of the membrane and its lysis. The model suggests that the oligomerization may play a role in toxin's activation process and provides insight into the structural principles of protein-membrane interactions.

Esophageal muscle physiology and morphogenesis require assembly of a collagen XIX-rich basement membrane zone

Collagen XIX is an extremely rare extracellular matrix component that localizes to basement membrane zones and is transiently expressed by differentiating muscle cells. Characterization of mice harboring null and structural mutations of the collagen XIX (Col19a1) gene has revealed the critical contribution of this matrix protein to muscle physiology and differentiation. The phenotype includes smooth muscle motor dysfunction and hypertensive sphincter resulting from impaired swallowing-induced, nitric oxide–dependent relaxation of the sphincteric muscle. Muscle dysfunction was correlated with a disorganized matrix and a normal complement of enteric neurons and interstitial cells of Cajal. Mice without collagen XIX exhibit an additional defect, namely impaired smooth-to-skeletal muscle cell conversion in the abdominal segment of the esophagus. This developmental abnormality was accounted for by failed activation of myogenic regulatory factors that normally drive esophageal muscle transdifferentiation. Therefore, these findings identify collagen XIX as the first structural determinant of sphincteric muscle function, and as the first extrinsic factor of skeletal myogenesis in the murine esophagus.

Predicting biomarkers for ovarian cancer using gene-expression microarrays

Ovarian cancer has the highest mortality rate of gynaecological cancers. This is partly due to the lack of effective screening markers. Here, we used oligonucleotide microarrays complementary to ∼12 000 genes to establish a gene-expression microarray (GEM) profile for normal ovarian tissue, as compared to stage III ovarian serous adenocarcinoma and omental metastases from the same individuals. We found that the GEM profiles of the primary and secondary tumours from the same individuals were essentially alike, reflecting the fact that these tumours had already metastasised and acquired the metastatic phenotype. We have identified a novel biomarker, mammaglobin-2 (MGB2), which is highly expressed specific to ovarian cancer. MGB2, in combination with other putative markers identified here, could have the potential for screening.

Gene expression array profile of human osteosarcoma

The aims of this pilot study were to determine whether needle and open biopsies from osteosarcoma (OS) provide sufficient quality of mRNA for cDNA array analyses to gain insights into the expression profile of OS. A total of 22 samples collected from OS were used for array analyses. A primary cell culture was also established from one of the OS biopsies. Total RNA was extracted and probes were generated for cDNA arrays. cDNA probes were made for all the 22 samples. Two of these samples were needle core bone biopsies. Statistical analysis confirmed the reliability of array data obtained in 16 of the 22 samples. Known genes involved in bone metabolism and osteosarcoma were identified as highly expressed, and the putative new marker Ezrin was also identified. Confirmatory immunohistochemical staining using the Ezrin antibody was performed in a selection of samples.

Differential brain activity in alcoholics and social drinkers to alcohol cues: relationship to craving

Using fMRI, our group previously found that after a sip of alcohol and exposure to alcohol beverage pictures, alcoholics compared to social drinkers had increased differential brain activity in the prefrontal cortex and anterior thalamus. This study extends this earlier work with several improvements including imaging the entire brain (rather than the anterior half previously) and recording craving, while the subjects viewed images within the scanner. In a Philips 1.5 T MRI scanner, 10 nontreatment-seeking alcoholics and 10 age-matched healthy social drinkers were given a sip of alcohol before viewing a 12 min randomized presentation of pictures of alcoholic beverages, nonalcoholic beverages, and two different visual control tasks. During picture presentation, changes in regional brain activity were measured in 15 transverse T2(*)-weighted blood oxygen level dependent slices. Subjects rated their urge to drink after each picture sequence. After a sip of alcohol, while viewing alcohol cues compared to viewing other beverage cues, the alcoholics, but not social drinkers, reported higher craving ratings and had increased activity in the prefrontal cortex and anterior limbic regions. Brain activity in the left nucleus accumbens, anterior cingulate, and left orbitofrontal cortex significantly correlated with subjective craving ratings in alcohol subjects but not in control subjects. This study suggests, as did our earlier study, that alcoholics and not social drinkers, when exposed to alcohol cues, have increased brain activity in areas that reportedly subserve craving for other addictive substances.

Neointimal formation after endovascular arterial injury is markedly attenuated in db/db mice

OBJECTIVE

A diabetic mouse model of accelerated neointimal formation would be a useful tool to understand the increased incidence of restenosis in patients with diabetes.

METHODS AND RESULTS

Femoral artery endoluminal wire injury was performed in diabetic insulin 2 Akita (ins2Akita) and leptin receptor db/db (leprdb/db) mutant mice. Neointima size in ins2Akita mouse arteries was unchanged compared with nondiabetic wild-type littermates. Although Ki67 labeling demonstrated similar rates of replication in the neointima of leprdb/db mouse arteries, neointimal formation in leprdb/db mice was surprisingly reduced by approximately 90% compared with nondiabetic lepr+/+ mice. Four hours after arterial injury, medial smooth muscle cell death was diminished in leprdb/db arteries, suggesting that the initial response to arterial injury was altered in leprdb/db mice.

CONCLUSIONS

These studies highlight a differential response to arterial injury in leprdb/db mice and suggest a potential role for leptin in the regulation of neointimal formation in response to arterial injury.

RNF5, a RING finger protein that regulates cell motility by targeting paxillin ubiquitination and altered localization

RNF5 is a RING finger protein found to be important in the growth and development of Caenorhabditis elegans. The search for RNF5-associated proteins via a yeast two-hybrid screen identified a LIM-containing protein in C. elegans which shows homology with human paxillin. Here we demonstrate that the human homologue of RNF5 associates with the amino-terminal domain of paxillin, resulting in its ubiquitination. RNF5 requires intact RING and C-terminal domains to mediate paxillin ubiquitination. Whereas RNF5 mediates efficient ubiquitination of paxillin in vivo, protein extracts were required for in vitro ubiquitination, suggesting that additional modifications and/or an associated E3 ligase assist RNF5 targeting of paxillin ubiquitination. Mutant Ubc13 efficiently inhibits RNF5 ubiquitination, suggesting that RNF5 generates polychain ubiquitin of the K63 topology. Expression of RNF5 increases the cytoplasmic distribution of paxillin while decreasing its localization within focal adhesions, where it is primarily seen under normal growth. Concomitantly, RNF5 expression results in inhibition of cell motility. Via targeting of paxillin ubiquitination, which alters its localization, RNF5 emerges as a novel regulator of cell motility.

Clinical characteristics of under-reporters on urine drug screens in a cocaine treatment study

To explore the concordance between urine drug screen (UDS) results and self-report of cocaine use, results in a pharmacologic treatment trial for cocaine dependence were evaluated. Subjects with at least two occurrences of a positive UDS for cocaine were characterized as either an under-reporter (UR, n = 43) or a truthful reporter (TR, n = 32). Interestingly, URs attended more study sessions and were more likely to complete the study. Significant differences were found in cocaine use patterns and the prevalence of Axis I and Axis II disorders. This information may be important in guiding the judicious use of UDS in clinical and research settings.

Homeobox protein, Hmx3, in postnatally developing rat submandibular glands

Homeobox-containing (Hox) genes play important roles in development, particularly in the development of neurons and sensory organs, and in specification of body plan. The Hmx gene family is a new class of homeobox-containing genes defined by a conserved homeobox region and a characteristic pattern of expression in the central nervous system that is more rostral than that of the Hox genes. To date, three closely related members of the Hmx family, Hmx1, Hmx2, and Hmx3, have been described. All three Hmx genes are expressed in the craniofacial region of developing embryos. Here we show, for the first time, the expression of the transcription factor Hmx3 in postnatally developing salivary glands. Hmx3 protein is expressed in a cell type-specific manner in rat salivary glands. Hmx3 is present in both the nuclei and cytoplasm of specific groups of duct cells of the submandibular, parotid, and sublingual glands. Hmx3 expression increases during postnatal development of the submandibular gland. The duct cells show increasing concentrations of Hmx3 protein with progressive development of the submandibular gland. In contrast, the acinar cells of the three salivary glands do not exhibit detectable levels of Hmx3 protein.

The National Survey of Mental Health and Well-Being in Australia: impact on policy

OBJECTIVE

To provide a synopsis of the 3-part National Survey of Mental Health and Well-Being in Australia and to examine the yield in terms of policy and other changes in mental and general health services.

METHOD

Published data are examined, and a commentary is provided on service-delivery issues that the data have revealed.

RESULTS

One-year prevalence estimates for the common mental disorders, defined according to ICD-10 criteria and assessed using the automated version of the Composite International Diagnostic Interview (CIDI-A), have indicated rates similar to those of other countries (17.7%). Alarmingly high rates were found for alcohol and substance abuse in young persons, especially among young men. The number of years of life lost owing to disability attributable to mental disorders exceeds the number lost owing to cardiovascular disease and cancer. Only 35% of persons with 1 or more of the common mental disorders had sought help in the 12 months prior to interview. The point prevalence for mental health problems was 14% for persons aged 4 to 17 years. The point prevalence for psychotic disorders was 4.7 per 1000. An encouraging finding is that 81% of affected individuals had been to their general practitioner (GP) in the last year. However, only 20% had participated in any rehabilitation program in the past year.

CONCLUSIONS

The Survey results are based on a national population sample, not on individuals reaching services. They have therefore proved to be of great value in influencing policy at federal and state levels and may have contributed to increased funding for both services and research.

Well-being in Australia--findings from the National Survey of Mental Health and Well-being

BACKGROUND

The National Survey of Mental Health and Well-being in Australia has provided a rare opportunity to investigate not only the sociodemographic distribution of well-being, but also how it is related to impaired mental or physical health, to specific groups of psychiatric disorders and disability in daily life.

METHODS

A national household sample of 10,641 individuals (response rate 78 %) representative of the adult population was interviewed with the Composite International Diagnostic Interview and completed scales measuring recent symptoms, disablement and well-being. The latter was measured by the single item Life Satisfaction Scale of Andrews and Withey (1976) expressed as percentage, with 100 % being "delighted".

RESULTS

The mean score for the Australian adult population was 70.4 % (95 % CI 70.0, 70.8), which matches the proposed universal norm. Men and women had very similar mean scores. Well-being was higher in persons with tertiary education and in those owning or purchasing their homes. It was lower in persons with physical or mental disorders, particularly depression. For alcohol use, a U-shaped relationship was found, whereby well-being was lower both in abstainers and in heavy users. Multiple regression analysis showed that when adjustment is made for confounders, women had higher life satisfaction than men and that high life satisfaction became less common with age in men, but even more so in women. Life satisfaction was impaired for respondents with high psychological distress, especially in the unemployed, the divorced and those with tertiary education, whether or not their symptoms led to a CIDI-A diagnosis of depression.

CONCLUSION

The correlates of well-being are essentially in the expected direction. Depressive disorder has a stronger association with low well-being than other psychiatric diagnoses. Of particular interest is the existence of a small number of persons with current anxiety or depressive disorders who report having high life satisfaction. This deserves further investigation.

Polyploidy, phylogeography and Pleistocene refugia of the rockfern Asplenium ceterach: evidence from chloroplast DNA

Chloroplast DNA sequences were obtained from 331 Asplenium ceterach plants representing 143 populations from throughout the range of the complex in Europe, plus outlying sites in North Africa and the near East. We identified nine distinct haplotypes from a 900 bp fragment of trnL-trnF gene. Tetraploid populations were encountered throughout Europe and further afield, whereas diploid populations were scarcer and predominated in the Pannonian-Balkan region. Hexaploids were encountered only in southern Mediterranean populations. Four haplotypes were found among diploid populations of the Pannonian-Balkans indicating that this region formed a northern Pleistocene refugium. A separate polyploid complex centred on Greece, comprises diploid, tetraploid and hexaploid populations with two endemic haplotypes and suggests long-term persistence of populations in the southern Mediterranean. Three chloroplast DNA (cpDNA) haplotypes were common among tetraploids in Spain and Italy, with diversity reducing northwards suggesting expansion from the south after the Pleistocene. Our cpDNA and ploidy data indicate at least six independent origins of polyploids.

Neurological and perceptual-motor outcome at 5 - 6 years of age in children with neonatal encephalopathy: relationship with neonatal brain MRI

OBJECTIVE

The aims of this study were 1) to determine the incidence of minor neurological dysfunction and perceptual-motor difficulties in children aged 5-1/2 -- 6-1/2, who had been born full-term but presented with neonatal encephalopathy (NE) and low Apgar scores and 2) to examine the relationships between the presence/absence of these difficulties with neonatal brain MRI.

PARTICIPANTS AND METHODS

Sixty-eight full-term infants with one minute Apgar scores less than or equal to 5 and neurological abnormalities during the first 48 hours after birth were included in the study. All children had a neonatal MRI brain scan. Surviving infants were assessed between the age of 5 and 6 years using the Touwen Examination, the Movement ABC and the WPPSI-R.

RESULTS

Fifteen of the 68 infants (22 %) died in the neonatal period. Of the 53 surviving infants, 19 (36 %) had cerebral palsy. The remaining 34 were considered normal at 2 years of age but, when assessed at school age, 8 (15 %) had minor neurological dysfunction and/or perceptual-motor difficulties, 1 (2 %) had only cognitive impairment and 25 (47 %) were normal. The outcome largely reflected the pattern of lesions on brain imaging. While 83 % of those with a normal outcome had normal scans or minimal white matter lesions, 80 % of those with minor neurological dysfunction and/or perceptual-motor difficulties had mild or moderate basal ganglia or more marked white matter lesions.

CONCLUSION

Continued surveillance is recommended for children with apparently normal outcome at two years of age after NE, particularly when abnormalities are detected on brain MRI.