Spatial dynamics and molecular ecology of North American rabies

Rabies, caused by a single-stranded RNA virus, is arguably the most important viral zoonotic disease worldwide. Although endemic throughout many regions for millennia, rabies is also undergoing epidemic expansion, often quite rapid, among wildlife populations across regions of Europe and North America. A current rabies epizootic in North America is largely attributable to the accidental introduction of a particularly well-adapted virus variant into a naive raccoon population along the Virginia/West Virginia border in the mid-1970s. We have used the extant database on the spatial and temporal occurrence of rabid raccoons across the eastern United States to construct predictive models of disease spread and have tied patterns of emergence to local environmental variables, genetic heterogeneity, and host specificity. Rabies will continue to be a remarkable model system for exploring basic issues in the temporal and spatial dynamics of expanding infectious diseases and examining ties between disease population ecology and evolutionary genetics at both micro- and macro-evolutionary time scales.

Hedgehog and Fgf signaling pathways regulate the development of tphR-expressing serotonergic raphe neurons in zebrafish embryos

Serotonin (5HT) plays major roles in the physiological regulation of many behavioral processes, including sleep, feeding, and mood, but the genetic mechanisms by which serotonergic neurons arise during development are poorly understood. In the present study, we have investigated the development of serotonergic neurons in the zebrafish. Neurons exhibiting 5HT-immunoreactivity (5HT-IR) are detected from 45 h postfertilization (hpf) in the ventral hindbrain raphe, the hypothalamus, pineal organ, and pretectal area. Tryptophan hydroxylases encode rate-limiting enzymes that function in the synthesis of 5HT. As part of this study, we cloned and analyzed a novel zebrafish tph gene named tphR. Unlike two other zebrafish tph genes (tphD1 and tphD2), tphR is expressed in serotonergic raphe neurons, similar to tph genes in mammalian species. tphR is also expressed in the pineal organ where it is likely to be involved in the pathway leading to synthesis of melatonin. To better understand the signaling pathways involved in the induction of the serotonergic phenotype, we analyzed tphR expression and 5HT-IR in embryos in which either Hh or Fgf signals are abrogated. Hindbrain 5HT neurons are severely reduced in mutants lacking activity of either Ace/Fgf8 or the transcription factor Noi/Pax2.1, which regulates expression of ace/fgf8, and probably other genes encoding signaling proteins. Similarly, serotonergic raphe neurons are absent in embryos lacking Hh activity confirming a conserved role for Hh signals in the induction of these cells. Conversely, over-activation of the Hh pathway increases the number of serotonergic neurons. As in mammals, our results are consistent with the transcription factors Nk2.2 and Gata3 acting downstream of Hh activity in the development of serotonergic raphe neurons. Our results show that the pathways involved in induction of hindbrain serotonergic neurons are likely to be conserved in all vertebrates and help establish the zebrafish as a model system to study this important neuronal class.

Adcon -L gel and intraoperative hypotension during lumbar discectomy

This case report describes an intraoperative hypotensive event associated temporally with application of topical Adcon -L gel during lumbar surgery. Documented serum cardiac and immunological markers suggest a non-anaphylactoid aetiology. The aetiology of this phenomenon is discussed with reference to available literature.

A cohort study of early neurological consultation by telemedicine on the care of neurological inpatients

OBJECTIVES

To find out the effect of early neurological consultation using a real time video link on the care of patients with neurological symptoms admitted to hospitals without neurologists on site.

METHODS

A cohort study was performed in two small rural hospitals: Tyrone County Hospital (TCH), Omagh, and Erne Hospital, Enniskillen. All patients over 12 years of age who had been admitted because of neurological symptoms, over a 24 week period, to either hospital were studied. Patients admitted to TCH, in addition to receiving usual care, were offered a neurological consultation with a neurologist 120 km away at the Neurology Department of the Royal Victoria Hospital, Belfast, using a real time video link. The main outcome measure was length of hospital stay; change of diagnosis, mortality at 3 months, inpatient investigation, and transfer rate and use of healthcare resources within 3 months of admission were also studied.

RESULTS

Hospital stay was significantly shorter for those admitted to TCH (hazard ratio 1.13; approximate 95% CI 1.003 to 1.282; p = 0.045). No patients diagnosed by the neurologist using the video link subsequently had their diagnosis changed at follow up. There was no difference in overall mortality between the groups. There were no differences in the use of inpatient hospital resources and medical services in the follow up period between TCH and Erne patients.

CONCLUSIONS

Early neurological assessment reduces hospital stay for patients with neurological conditions outside of neurological centres. This can be achieved safely at a distance using a real time video link.

Removal of ocular artifacts from electro-encephalogram by adaptive filtering

The electro-encephalogram (EEG) is useful for clinical diagnosis and in biomedical research. EEG signals, however, especially those recorded from frontal channels, often contain strong electro-oculogram (EOG) artifacts produced by eye movements. Existing regression-based methods for removing EOG artifacts require various procedures for preprocessing and calibration that are inconvenient and time-consuming. The paper describes a method for removing ocular artifacts based on adaptive filtering. The method uses separately recorded vertical EOG and horizontal EOG signals as two reference inputs. Each reference input is first processed by a finite impulse response filter of length M (M = 3 in this application) and then subtracted from the original EEG. The method is implemented by a recursive least-squares algorithm that includes a forgetting factor (lambda = 0.9999 in this application) to track the non-stationary portion of the EOG signals. Results from experimental data demonstrate that the method is easy to implement and stable, converges fast and is suitable for on-line removal of EOG artifacts. The first three coefficients (up to M = 3) were significantly larger than any remaining coefficients.

Interviewing vulnerable old people: ethical and methodological implications of imagining our subjects

It is sometimes argued that interview research with vulnerable social groups, such as frail, lonely, older people, has distinctive ethical and methodological requirements. The conventional one-off, professional interview is seen to be both inadequate as a method of data collection and inimical to the interest of research subjects. While ideologically persuasive, such a view is not derived from systematic analysis of actual interviews. In this article, I describe a research project on social isolation in which the conceptualization of elderly interviewees as "vulnerable subjects" had a number of critical but intended impacts on the course and outcomes of the research. I offer an empirically grounded analysis of the interview situation that suggests an alternative reading of the relationship between social representation of aging persons and the methods we use to study them.

Development of an assessment tool to measure the influence of clinical software on the delivery of high quality consultations. A study comparing two computerized medical record systems in a nurse run heart clinic in a general practice setting

A rating scale was developed to assess the contribution made by computer software towards the delivery of a quality consultation, with the purpose of informing the development of the next generation of systems. Two software programmes were compared, using this scale to test their ability to enable or inhibit the delivery of an ideal consultation with a patient with heart disease. The context was a general practice based, nurse run clinic for the secondary prevention of heart disease. One of the programmes was customized for this purpose; the other was a standard general practice programme. Consultations were video-recorded, and then assessed by an expert panel using the new assessment tool. Both software programmes were oriented towards the implementation of the evidence, rather than facilitating patient-centred practice. The rating scale showed, not surprisingly, significantly greater support from the customized software in the consultation in five out of eight areas. However, the scale's reliability measured by Cronbach's Alpha, was sub-optimal. With further refinement, this rating scale may become a useful tool that will inform software developers of the effectiveness of their programmes in the consultation, and suggest where they need development.

CD40 activation-induced, Fas-dependent apoptosis and NF-kappaB/AP-1 signaling in human intrahepatic biliary epithelial cells

Fas-mediated mechanisms of apoptosis are thought to be involved in the bile duct loss that characterizes diseases such as primary biliary cirrhosis (PBC). We have previously shown that activation of CD40 on hepatocytes can amplify Fas-mediated apoptosis; in the present study, we investigated interactions between CD40 and Fas in biliary epithelial cells (BEC). We report that the bile ducts in PBC liver tissue frequently express increased levels of Fas, Fas ligand (FasL), and CD40 associated with apoptotic BEC. The portal mononuclear infiltrate contains CD40L+ve T cells and macrophages, thereby demonstrating a potential mechanism for CD40 engagement in vivo. Primary cultures of human BEC also expressed Fas, FasL, and CD40 but not CD40L protein or mRNA. Activation of CD40 on BEC using recombinant CD40L increased transcriptional expression of FasL and induced apoptosis, which was inhibited by neutralizing antibodies to either Fas or FasL. Thus, CD40-induced apoptosis of BEC is mediated through Fas/FasL. We then investigated the intracellular signals and transcription factors activated in BEC and found that NF-kappaB and AP-1 were both activated after CD40 ligation. Increased functional NF-kappaB was seen early after CD40 ligation, but returned to baseline levels after 4 h. In contrast, the rapid up-regulation of AP-1 was sustained over 24 h. This study provides further functional evidence of the ability of CD40 to induce Fas/FasL-dependent apoptosis of liver epithelial cells supporting the importance of cross-talk between tumor necrosis factor (TNF) receptor family members as an amplification step in apoptosis induction. Sustained activation of AP-1 in the absence of NF-kappaB signaling may be a critical factor in determining the outcome of CD40 engagement.

Follow-up of a large cohort of Black women

High retention rates in follow-up studies reduce the potential for biased data due to selective losses. The Black Women's Health Study began in 1995 when 64,500 participants aged 21-69 years enrolled by completing postal health questionnaires. Follow-up is carried out biennially. On the basis of data collected between enrollment and completion of the first follow-up, the authors assessed the usefulness of various follow-up methods and compared the characteristics of respondents, nonrespondents, and women lost to follow-up because of an unknown address. The 1997 questionnaire was completed by 82.8% of the participants. The study population was highly mobile: 56.5% moved at least once, and 1.5% moved at least four times. Moving was associated with younger age: A total of 71.7% of participants aged 21-29 years moved at least once compared with 43.2% of women aged 50-69. The most successful and cost-effective method for eliciting completed questionnaires from participants was sending multiple waves of questionnaires. Telephone calls to nonrespondents were successful but were highly labor intensive. Demographic and health characteristics of the women were similar regardless of which mailing was completed, except that early respondents had higher levels of education. Respondents were more highly educated and older than were nonrespondents and lost subjects but were quite similar in all other characteristics. These data suggest that follow-up of a mobile population of African-American women can be successful.

Critical analysis of everyday self-care decision making in chronic illness

AIMS OF THE PAPER

The purpose of the paper is to (1) identify prevalent assumptions that underlie the traditional conceptualization of everyday self-care decision making and (2) contrast these with the findings of relevant research.

BACKGROUND/RATIONALE

Current understandings of self-care decision making in chronic illness tend to be extrapolated from knowledge gained in relation to one-time decisions, or decision making in contexts that are only superficially related to the complexity and pervasiveness of living with a chronic disease.

FINDINGS

The authors challenge the assumptions with which current understandings represent self-care decision making in chronic illness, using evidence from their research on what it is like to live with and manage the implications of having a chronic disease on an everyday basis.

CONCLUSIONS

The paper concludes with a call for a new conceptualization of self-care decision making in chronic illness which sufficiently addresses the unique and complex nature of such decisions.

Segmentation, attention and phenomenal visual objects

Issues concerning selective attention provoke new questions about visual segmentation, and vice-versa. We illustrate this by describing our recent work on grouping under conditions of inattention, on change blindness for background events and the residual processing of undetected background changes, on modal versus amodal completion in visual search, and the differential effects of these two forms of completion on attentional processes, and on attentional modulation of lateral interactions thought to arise in early visual cortex. Many of these results indicate that segmentation processes substantially constrain attentional processes, but the reverse influence is also apparent, suggesting an interactive architecture. We discuss how the 'proto-objects' revealed by studies of segmentation and attention (i.e. the segmented perceptual units which constrain selectivity) may relate to other object-based notions in cognitive science, and we wrestle with their relation to phenomenal visual awareness.

Transperitoneal guide-wire or drainage catheter placement for guidance of laparoscopic marsupialization of lymphocoeles post renal transplantation

BACKGROUND

Lymphocoeles post renal transplantation can be difficult to see laparoscopically. The objective of this study was to report a new technique of catheter or guide-wire placement for the guidance of laparoscopic marsupialization of symptomatic post renal transplant lymphocoeles, refractory to conservative therapy.

METHODS

Conventional aseptic technique under local anaesthesia was used for guide-wire or catheter insertion, with the difference being the use of a transperitoneal approach. Computerized tomography (CT) or ultrasound (US) guidance was used. All lesions were confirmed to be sterile lymphocoeles beforehand by either needle aspiration or previous catheter drainage.

RESULTS

Four catheters and one guide-wire were placed pre-operatively without complication. All cases underwent satisfactory laparoscopic marsupialization. No immediate complications were noted in any patient. The drainage catheters were inserted between 5 and 19 days before laparoscopic marsupialization, and guide-wire inserted immediately before. All patients proceeded to laparoscopic marsupialization.

CONCLUSIONS

This technique offers precise guidance on laparoscopic surgery, is relatively simple to perform and no complications were experienced in this study. Its use is limited to sterile and benign lesions due to the risks of peritoneal seeding, making recurrent post-operative lymphocoeles ideally suited for this application.

Mapping HLA for single nucleotide polymorphisms

Knowledge of DNA sequence variation may help us understand how genetic variability gives rise to functional variability and, in so doing, revolutionize the development of strategies to combat and prevent disease. Single nucleotide polymorphisms (SNPs) are stable, inherited, biallelic, single base pair differences which are present in the human genome at a density of 1 to 10 per 1,000 nucleotides. It is anticipated that SNPs will account for much of the functional heterogeneity in gene expression and protein activity exhibited in the human population. Susceptibility to or protection from a number of diseases, particularly those of autoimmune etiology, has been associated with specific alleles of the human leukocyte antigen (HLA) complex. Interestingly, the precise molecular defects in the HLA genes are unknown and the notion that non-HLA genes, within the same chromosomal region, are involved remains a formal possibility. We have determined the nucleotide sequence of a contiguous 2.2 Mbp segment of chromosome six that includes all of the HLA class I region, and have identified over 10,000 SNPs therein. Because of the derivative knowledge of gene and SNP content and position, the scientific community is now uniquely poised to identify disease-contributory SNPs that lie within the MHC.

Home enteral tube feeding following cerebrovascular accident

BACKGROUND AND AIMS

In the UK, cerebrovascular accident (CVA) is the third commonest cause of death and the commonest diagnosis in patients receiving home enteral feeding (HETF). This study aimed to use data from the British Artificial Nutrition Survey (BANS) collected between 1996 and 1999 to assess the outcome of patients on HETF, including mortality, return to oral feeding, level of physical activity, and level of dependency, which has resource implications.

RESULTS

it is estimated that about 1.7% of all patients suffering a CVA in the UK between 1996 and 1999 received HETF. At one year, 29.6% died while receiving HETF and another 13% returned to oral feeding. Mortality increased with age and was twice as high in those managed in nursing homes compared to those in their own homes. The patients receiving tube feeding spent only 0.6% of their time in hospital. A total of 43.9% of patients were bed-bound at home (1.9% unconscious) and an additional 30.3% were house-bound. Only 21.2% were independent, and the majority were totally dependent on their carers. In CVA patients on HETF the level of dependency was greater than for those with all types of diagnoses (n=12,997).

CONCLUSION

This study has described the outcome of a large number of patients receiving HETF in the UK. Since patients spent less than 1% of their time in hospital, HETF relieves pressure on the expensive hospital environment, but places more demands on the carers, who have to deal with severely disabled patients. Recovery of swallowing function should be assessed intermittently to prevent unnecessary HETF.

Intrathecal treatment of neoplastic meningitis due to breast cancer with a slow-release formulation of cytarabine

DepoCyte is a slow-release formulation of cytarabine designed for intrathecal administration. The goal of this multi-centre cohort study was to determine the safety and efficacy of DepoCyte for the intrathecal treatment of neoplastic meningitis due to breast cancer. DepoCyte 50 mg was injected once every 2 weeks for one month of induction therapy; responding patients were treated with an additional 3 months of consolidation therapy. All patients had metastatic breast cancer and a positive CSF cytology or neurologic findings characteristic of neoplastic meningitis. The median number of DepoCyte doses was 3, and 85% of patients completed the planned 1 month induction. Median follow up is currently 19 months. The primary endpoint was response, defined as conversion of the CSF cytology from positive to negative at all sites known to be positive, and the absence of neurologic progression at the time the cytologic conversion was documented. The response rate among the 43 evaluable patients was 28% (CI 95%: 14-41%); the intent-to-treat response rate was 21% (CI 95%: 12-34%). Median time to neurologic progression was 49 days (range 1-515(+)); median survival was 88 days (range 1-515(+)), and 1 year survival is projected to be 19%. The major adverse events were headache and arachnoiditis. When drug-related, these were largely of low grade, transient and reversible. Headache occurred on 11% of cycles; 90% were grade 1 or 2. Arachnoiditis occurred on 19% of cycles; 88% were grade 1 or 2. DepoCyte demonstrated activity in neoplastic meningitis due to breast cancer that is comparable to results reported with conventional intrathecal agents. However, this activity was achieved with one fourth as many intrathecal injections as typically required in conventional therapy. The every 2 week dose schedule is a major advantage for both patients and physicians.

Changing faces: a detection advantage in the flicker paradigm

Observers seem surprisingly poor at detecting changes in images following a large transient or flicker. In this study, we compared this change blindness phenomenon between human faces and other common objects (e.g., clothes). We found that changes were detected far more rapidly and accurately in faces than in other objects. This advantage for faces, however, was found only for upright faces in multiple-object arrays, and was completely eliminated when displays showed one photograph only or when the pictures were inverted. These results suggest a special role for faces in competition for visual attention, and provide support for previous claims that human faces are processed differently than stimuli that may be of less biological significance.

A nodal signaling pathway regulates the laterality of neuroanatomical asymmetries in the zebrafish forebrain

Animals show behavioral asymmetries that are mediated by differences between the left and right sides of the brain. We report that the laterality of asymmetric development of the diencephalic habenular nuclei and the photoreceptive pineal complex is regulated by the Nodal signaling pathway and by midline tissue. Analysis of zebrafish embryos with compromised Nodal signaling reveals an early role for this pathway in the repression of asymmetrically expressed genes in the diencephalon. Later signaling mediated by the EGF-CFC protein One-eyed pinhead and the forkhead transcription factor Schmalspur is required to overcome this repression. When expression of Nodal pathway genes is either absent or symmetrical, neuroanatomical asymmetries are still established but are randomized. This indicates that Nodal signaling is not required for asymmetric development per se but is essential to determine the laterality of the asymmetry.

Interactive videoconsultation is a feasible method for neurological in-patient assessment

To evaluate the feasibility of interactive videoconsultation (IATV) as a means by which neurologists might assess patients admitted with neurological symptoms to hospitals distant from a neurological centre, we studied 25 unselected patients using interactive videoconsultation (IATV) and then validated the IATV diagnoses and management plans at a later face-to-face consultation. IATV consultation led to an eventual diagnosis in 23 out of 25 patients, with one diagnosis being changed and one remaining uncertain. The IATV management plans were felt to be appropriate for all patients in study. Twelve patients were able to be discharged from hospital on the same day as IATV on the advice of the neurologist. It is therefore practical to assess patients admitted with neurological symptoms to distant hospitals using IATV and this may result in more efficient use of in-patient resources.