Age-related changes in brain hemodynamics; A calibrated MRI study

INTRODUCTION

Blood oxygenation-level dependent (BOLD) magnetic resonance imaging signal changes in response to stimuli have been used to evaluate age-related changes in neuronal activity. Contradictory results from these types of experiments have been attributed to differences in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2 ). To clarify the effects of these physiological parameters, we investigated the effect of age on baseline CBF and CMRO2 .

MATERIALS AND METHODS

Twenty young (mean ± sd age, 28 ± 3 years), and 45 older subjects (66 ± 4 years) were investigated. A dual-echo pseudocontinuous arterial spin labeling (ASL) sequence was performed during normocapnic, hypercapnic, and hyperoxic breathing challenges. Whole brain and regional gray matter values of CBF, ASL cerebrovascular reactivity (CVR), BOLD CVR, oxygen extraction fraction (OEF), and CMRO2 were calculated.

RESULTS

Whole brain CBF was 49 ± 14 and 40 ± 9 ml/100 g/min in young and older subjects respectively (P < 0.05). Age-related differences in CBF decreased to the point of nonsignificance (B=-4.1, SE=3.8) when EtCO2 was added as a confounder. BOLD CVR was lower in the whole brain, in the frontal, in the temporal, and in the occipital of the older subjects (P<0.05). Whole brain OEF was 43 ± 8% in the young and 39 ± 6% in the older subjects (P = 0.066). Whole brain CMRO2 was 181 ± 60 and 133 ± 43 µmol/100 g/min in young and older subjects, respectively (P<0.01).

DISCUSSION

Age-related differences in CBF could potentially be explained by differences in EtCO2 . Regional CMRO2 was lower in older subjects. BOLD studies should take this into account when investigating age-related changes in neuronal activity.

Impact of Water Management on Efficacy of Insecticide Seed Treatments Against Rice Water Weevil (Coleoptera: Curculionidae) in Mississippi Rice

Two experiments were conducted at the Delta Research and Extension Center in Stoneville, MS, during 2011 and 2012 to determine the impact of water management practices on the efficacy of insecticidal seed treatments targeting rice water weevil, Lissorhoptrus oryzophilus Kuschel. Larval densities and yield were compared for plots treated with labeled rates of thiamethoxam, chlorantraniliprole, and clothianidin and an untreated control. In the first experiment, plots were subjected to flood initiated at 6 and 8 wk after planting. Seed treatments significantly reduced larval densities with the 8-wk flood timing, but not the 6-wk flood timing. Overall, the treated plots yielded higher than the control plots. In the second experiment, the impact of multiple flushes on the efficacy of insecticidal seed treatments was evaluated. Plots were subjected to zero, one, or two flushes with water. All seed treatments reduced larval densities compared with the untreated control. Significantly fewer larvae were observed in plots that received one or two flushes compared with plots that did not receive a flush. All seed treatments resulted in higher yields compared to the untreated control in the zero and one flush treatments. When two flushes were applied, yield from the thiamethoxam and clothianidin treated plots was not significantly different from those of the control plots, while the chlorantraniliprole treated plots yielded significantly higher than the control. These data suggest that time from planting to flood did not impact the efficacy of seed treatments, but multiple flushes reduced the efficacy of thiamethoxam and clothianidin.

Examination of the early infection stages of koi herpesvirus (KHV) in experimentally infected carp, Cyprinus carpio L. using in situ hybridization

Koi herpesvirus (KHV) causes a highly infectious disease afflicting common carp and koi, Cyprinus carpio L. Various molecular and antibody-based detection methods have been used to elucidate the rapid attachment and dissemination of the virus throughout carp tissues, facilitating ongoing development of effective diagnostic approaches. In situ hybridization (ISH) was used here to determine the target tissues of KHV during very early infection, after infecting carp with a highly virulent KHV isolate. Analysis of paraffin-embedded tissues (i.e. gills, skin, spleen, kidney, gut, liver and brain) during the first 8 h and following 10 days post-infection (hpi; dpi) revealed positive signals in skin mucus, gills and gut sections after only 1 hpi. Respiratory epithelial cells were positive as early as 2 hpi. Viral DNA was also detected within blood vessels of various tissues early in the infection. Notable increases in signal abundance were observed in the gills and kidney between 5 and 10 dpi, and viral DNA was detected in all tissues except brain. This study suggests that the gills and gut play an important role in the early pathogenesis of this Alloherpesvirus, in addition to skin, and demonstrates ISH as a useful diagnostic tool for confirmation of acutely infected carp.

Sensitivity of seven PCRs for early detection of koi herpesvirus in experimentally infected carp, Cyprinus carpio L., by lethal and non-lethal sampling methods

Koi herpesvirus (KHV) causes an economically important, highly infectious disease in common carp and koi, Cyprinus carpio L. Since the occurrence of mass mortalities worldwide, highly specific and sensitive molecular diagnostic methods have been developed for KHV detection. The sensitivity and reliability of these assays have essentially focused at the detection of low viral DNA copy numbers during latent or persistent infections. However, the efficacy of these assays has not been investigated with regard to low-level viraemia during acute infection stages. This study was conducted to compare the sensitivity of seven different polymerase chain reaction (PCR) assays to detect KHV during the first hours and days post-infection (hpi; dpi), using lethal and non-lethal sampling methods. The results highlight the limitations of the assays for detecting virus during the first 4 dpi despite rapid mortality in experimentally infected carp. False-negative results were associated with time post-infection and the tissue sampled. Non-lethal sampling appears effective for KHV screening, with efficient detection in mucus samples obtained from external swabs during this early infection period (<5 dpi), while biopsies from gills and kidney were negative using the same PCR assays. Non-lethal sampling may improve the reliability of KHV detection in subclinical, acutely infected carp.

Impact of fatal cases on the epidemiology of traumatic spinal cord injury in Estonia

BACKGROUND AND PURPOSE

Most epidemiological studies on traumatic spinal cord injury (TSCI) have not included patients who die before hospitalization. The aim of the research was to study the incidence of TSCI by including the individuals who die at the scene of the accident in addition to data retrieved from all hospitals in Estonia.

METHODS

Medical records of patients with TSCI from all hospitals in Estonia from 2005 to 2007 were studied. With collaboration from the Estonian Forensic Science Institute the data of the victims of TSCI who died before hospitalization were included.

RESULTS

From 2005 to 2007, 391 TSCI cases were identified: 183 patients were found retrospectively from medical records and 208 cases were detected from autopsy reports. Fifty-three per cent of patients died before hospitalization. The annual incidence rate was 97.0 per million population (95% confidence interval 87.4-106.6). The mean age at injury was 44.4 ± 18.7 years. Motor vehicle accidents were the leading cause of TSCI amongst the individuals who died before hospitalization (75%). Falls accounted for the highest number of TSCIs (43%) amongst the patients who reached hospital.

CONCLUSIONS

Our study shows that, when the cases that die at the scene of the accident are included, the incidence of TSCI in Estonia rises from 39.7 to 97.0 per million population.

Neural stimulators: a guide to imaging and postoperative appearances

Implantable neural stimulators have been developed to aid patients with debilitating neurological conditions that are not amenable to other therapies. The aim of this article is to improve understanding of correct anatomical placement as well as the relevant imaging methods used to assess these devices. Potential complications following their insertion and an overview of the current indications and potential mechanism of action of these devices is provided.

Oral health care services utilisation in the adult US population: Medical Expenditure Panel Survey 2006

OBJECTIVES

To estimate the proportion of dental visits and to explore determinants of oral health care service (OHCS) utilisation among US civilian non-institutionalised adults.

METHODS

Cross-sectional data from the 2006 Medical Expenditure Panel Survey (MEPS) were used to analyse adults' self-reported dental visits across potential risk factors (n = 22,721). MEPS uses a complex sample design including stratification, clustering, multiple stages of selection, and disproportionate sampling. These survey design complexities were taken into account for analysis in this study. The analysis was performed in SAS 9.2 and used chi-square tests and binary logistic regression.

RESULTS

MEPS (2006) represented approximately 222 million non-institutionalised US adults. 42% (weighted) of this population reported a dental visit in the past 12 months. Dental visit numbers were observed to increase with age, with the 55-64-year-olds approximately 44% more likely than the 18-24-year olds to have visited the dentist in the past year. Hispanics were 48% less likely to report a dental visit compared to Non-Hispanic Whites. Respondents with public- or no- dental insurance were less likely to report a dental visit than persons with private dental coverage.

CONCLUSIONS

Under half the US adult civilian non-institutionalised population reported a dental visit during 2006. To help address utilisation disparities, creative initiatives and systemic approaches aimed at groups currently utilising OHCS less often could be an important step towards oral health equity.

An evaluation of hernia education in surgical residency programs

PURPOSE

The purpose of this study was to evaluate surgical residents' educational experience related to ventral hernias.

METHODS

A 16-question survey was sent to all program coordinators to distribute to their residents. Consent was obtained following a short introduction of the purpose of the survey. Comparisons based on training level were made using χ(2) test of independence, Fisher's exact, and Fisher's exact with Monte Carlo estimate as appropriate. A p value <0.05 was considered significant.

RESULTS

The survey was returned by 183 residents from 250 surgical programs. Resident postgraduate year (PG-Y) level was equivalent among groups. Preferred techniques for open ventral hernia varied; the most common (32 %) was intra-abdominal placement of mesh with defect closure. Twenty-two percent of residents had not heard of the retrorectus technique for hernia repair, 48 % had not performed the operation, and 60 % were somewhat comfortable with and knew the general categories of mesh prosthetics products. Mesh choices, biologic and synthetic, varied among the different products. The most common type of hernia education was teaching in the operating room in 87 %, didactic lecture 69 %, and discussion at journal club 45 %. Number of procedures, comfort level with open and laparoscopic techniques, indications for mesh use and technique, familiarity and use of retrorectus repair, and type of hernia education varied significantly based on resident level (p < 0.05).

CONCLUSION

Exposure to hernia techniques and mesh prosthetics in surgical residency programs appears to vary. Further evaluation is needed and may help in standardizing curriculums for hernia repair for surgical residents.

Comparing laparoscopic and open inguinal hernia repair in octogenarians

PURPOSE

To compare outcomes of laparoscopic and open inguinal hernia repair in elderly patients.

METHODS

We retrospectively reviewed patients ≥80 years old undergoing laparoscopic or open inguinal hernia repair from October 2006 to July 2009 at our medical center. Descriptive statistics were calculated, and outcomes were compared using Fisher's exact test, Wilcoxon rank-sum test, and Student's t test; a p value <0.05 was considered significant.

RESULTS

Open inguinal hernia repairs were performed in 58 patients, and laparoscopic repairs in 23 patients. There was no significant difference in average age (81 vs. 83 years, p = 0.09) or gender (91 % male vs. 74 % male, p = 0.1) for the laparoscopic versus open groups. Resident involvement (55 vs. 26 %, p = 0.02) was more common in the open group, and there was no difference in number of cases done for incarcerated hernias (17 vs. 13 %, p = 0.8) in the open versus laparoscopic groups. We observed a significant difference in hernia laterality and anesthesia type, with significantly more bilateral hernias (48 vs. 2 %, p ≤ 0.001) and more general anesthesia (100 vs. 31 %, p ≤ 0.001) in the laparoscopic compared with the open group. There were no significant differences in ASA score (p = 0.1), operating-room time (p = 0.6), urine output (p = 0.1), morbidity (p = 1), or mortality unrelated to the hernia surgery (13 vs. 22 %, p = 0.5) between the laparoscopic and open groups. At an average follow-up of 31 months (laparoscopic) and 19 months (open), only one recurrence occurred (open group).

CONCLUSIONS

Despite subtle differences between the laparoscopic and open approaches to inguinal hernia repairs in octogenarians, both procedures are safe with similar outcomes.

Ultrastructural morphogenesis of salmonid alphavirus 1

Studies on the ultrastructural morphogenesis of viruses give an insight into how the host cell mechanisms are utilized for new virion synthesis. A time course examining salmonid alphavirus 1 (SAV 1) assembly was performed by culturing the virus on Chinook salmon embryo cells (CHSE-214). Different stages of viral replication were observed under electron microscopy. Virus-like particles were observed inside membrane-bound vesicles as early as 1 h following contact of the virus with the cells. Membrane-dependent replication complexes were observed in the cytoplasm of the cells, with spherules found at the periphery of late endosome-like vacuoles. The use of intracellular membranes for RNA replication is similar to other positive-sense single-stranded RNA (+ssRNA) viruses. The number of Golgi apparatus and associated vacuoles characterized by 'fuzzy'-coated membranes was greater in virus-infected cells. The mature enveloped virions started to bud out from the cells at approximately 24 h post-infection. These observations suggest that the pathway used by SAV 1 for the generation of new virus particles in vitro is comparable to viral replication observed with mammalian alphaviruses but with some interesting differences.

A model of sexually and physically victimized women's process of attaining effective formal help over time: the role of social location, context, and intervention

As empirical evidence has demonstrated the pervasiveness of sexual assault and intimate partner violence in the lives of women, and the links to poor mental health outcomes, attention has turned to examining how women seek and access formal help. We present a conceptual model that addresses prior limitations and makes three key contributions: It foregrounds the influence of social location and multiple contextual factors; emphasizes the importance of the attainment of effective formal help that meets women's needs and leads to positive mental health outcomes; and highlights the role of interventions in facilitating help attainment. We conclude with research and practice implications.