Interpopulation differences and temporal synchrony in rates of adult survival between two seabird colonies that differ in population size and distance to foraging grounds.

Understanding the processes that drive interpopulation differences in demography and population dynamics is central to metapopulation ecology. In colonial species, populations are limited by local resource availability. However, individuals from larger colonies will travel greater distances to overcome density-dependent competition. Consequently, these individuals may also experience greater carry-over effects and interpopulation differences in demography. To test this prediction, we use mark-recapture data collected over four decades from two breeding colonies of a seabird, the Manx shearwater (Puffinus puffinus), that exhibit strong spatial overlap throughout the annual cycle but differ in population size and maximum foraging distances. We quantify interpopulation differences and synchrony in rates of survival and assess whether local mean wind speeds act to strengthen or disrupt synchrony. In addition, we examine whether the imputed interpopulation differences in survival can generate population-level consequences. The colony where individuals travel further during the breeding season had slightly lower and more variable rates of survival, indicative of individuals experiencing greater carry-over effects. Fluctuations in survival were highly synchronous between the colonies, but neither synchronous, nor asynchronous, variation could be strongly attributed to fluctuations in local mean wind speeds. Finally, we demonstrate that the imputed interpopulation differences in rates of survival could lead to considerable differences in population growth. We hypothesise that the observed interpopulation differences in rates of adult survival reflect carry-over effects associated with foraging distances during the breeding season. More broadly, our results highlight that breeding season processes can be important for understanding interpopulation differences in the demographic rates and population dynamics of long-lived species, such as seabirds.

Economic evaluation of DNA ploidy analysis vs liquid-based cytology for cervical screening.

BACKGROUND: DNA ploidy analysis involves automated quantification of chromosomal aneuploidy, a potential marker of progression toward cervical carcinoma. We evaluated the cost-effectiveness of this method for cervical screening, comparing five ploidy strategies (using different numbers of aneuploid cells as cut points) with liquid-based Papanicolaou smear and no screening. METHODS: A state-transition Markov model simulated the natural history of HPV infection and possible progression into cervical neoplasia in a cohort of 12-year-old females. The analysis evaluated cost in 2012 US$ and effectiveness in quality-adjusted life-years (QALYs) from a health-system perspective throughout a lifetime horizon in the US setting. We calculated incremental cost-effectiveness ratios (ICERs) to determine the best strategy. The robustness of optimal choices was examined in deterministic and probabilistic sensitivity analyses. RESULTS: In the base-case analysis, the ploidy 4 cell strategy was cost-effective, yielding an increase of 0.032 QALY and an ICER of $18 264/QALY compared to no screening. For most scenarios in the deterministic sensitivity analysis, the ploidy 4 cell strategy was the only cost-effective strategy. Cost-effectiveness acceptability curves showed that this strategy was more likely to be cost-effective than the Papanicolaou smear. CONCLUSION: Compared to the liquid-based Papanicolaou smear, screening with a DNA ploidy strategy appeared less costly and comparably effective.

Reliability of retrospective assignment of gross motor function classification system scores.

OBJECTIVES: To assess "alternate forms" reliability and inter-rater reliability of Gross Motor Function Classification System (GMFCS) scores. METHODS: Fifty randomly selected children with cerebral palsy were divided into two groups: (1) GMFCS score assigned during gait assessment ("GMFCS previously assigned") and (2) no GMFCS score assigned. Using database information, two physiotherapists independently determined GMFCS scores for 25 children from the "previously assigned" group, and 25 from the "no score assigned" group. Therapists compared their recently assigned scores for the "previously assigned" group, discussing discrepancies until attaining agreement. This group's consensus scores were compared to GMFCS scores assigned at time of actual assessment to calculate "alternate forms" reliability. RESULTS: Between-therapist agreements were kappa = 0.84 for "GMFCS previously assigned" group and 0.95 for "no GMFCS assigned" group. Kappa agreement between direct assessment and retrospectively assigned scores for the "GMFCS previously assigned" group was 0.79. CONCLUSIONS: Retrospective GMFCS scores can be reliably assigned.

Experimental studies of the role of the little raven (Corvus mellori) in surveillance for West Nile virus in Australia.

OBJECTIVE: To study the potential role of an Australian corvid, the little raven (Corvus mellori), in the surveillance for exotic West Nile virus (WNV) in Australia. METHOD: In a series of trials, little ravens were infected with WNV (strain 4132 New York 1999) and Kunjin virus (strain K42886) by the intramuscular route. They were observed for 20 days during which blood and swab samples were taken for virus isolation. Tissue samples were taken from ravens humanely killed during the acute infection period, and at the termination of the trials, for virus isolation, histopathology and immunohistochemistry. RESULTS: Ravens infected with WNV became mildly ill, but all recovered and seroconverted. Blood virus titres peaked around 3 to 4 days after inoculation at levels between 10(3.0) to 10(7.5) plaque forming units/mL. Virus or viral antigen was detected in spleen, liver, lung, kidney, intestine, testis and ovary by virus isolation and/or immunohistochemistry. WNV was detected in oral and cloacal swabs from 2 to 7 days post inoculation. The molecular and pathogenic characteristics of the inocula were consistent with them being of high virulence, as expected for this isolate. Ravens infected with Kunjin virus developed viraemia and seroconverted, although they did not develop disease. CONCLUSIONS: Little ravens do not develop severe disease in response to virulent WNV infection and for this reason may not be important sentinel hosts in the event of an outbreak of WNV, as in North America. However, as they have relatively high viraemias, they may be able to support virus cycles.

Deciduous canine and permanent lateral incisor differential root resorption.

When a permanent maxillary canine erupts apical to the permanent lateral incisor and the deciduous canine, resorption typically takes place only on the deciduous canine root. An understanding of this differential resorption could provide insight into the reasons for excessive iatrogenic root resorption during orthodontic tooth movement. The purpose of the present study was to examine the response of roots of permanent lateral incisors and deciduous canines to simulated resorption, and to acid and enzyme attack, reflecting the physiologic environment of an erupting permanent canine. Groups of maxillary permanent lateral incisor and deciduous canine roots were exposed to 5 combinations of Ten Cate demineralizing solution, Ten Cate demineralizing solution with EDTA, and a Type I collagenase solution. Sections of the roots were examined under a polarized light microscope. Analysis of variation of the resulting root lesions demonstrated that the lesion depths for deciduous canines were greater than those for permanent lateral incisors when averaged across 4 of the conditions (F(1,24) = 7.49, P =.0115). On average, deciduous canine roots demonstrated lesions 10% deeper than did permanent lateral incisor roots. We concluded that when deciduous canine and permanent lateral incisor roots are subjected to acid and enzyme attack, reflecting the physiologic environment of an erupting permanent canine, significantly deeper demineralized lesions are seen in the deciduous roots compared with the permanent roots. This finding may partially explain the differential root resorption during permanent tooth eruption.

Syntenic organization of the mouse distal chromosome 7 imprinting cluster and the Beckwith-Wiedemann syndrome region in chromosome 11p15.5.

In human and mouse, most imprinted genes are arranged in chromosomal clusters. Their linked organization suggests co-ordinated mechanisms controlling imprinting and gene expression. The identification of local and regional elements responsible for the epigenetic control of imprinted gene expression will be important in understanding the molecular basis of diseases associated with imprinting such as Beckwith-Wiedemann syndrome. We have established a complete contig of clones along the murine imprinting cluster on distal chromosome 7 syntenic with the human imprinting region at 11p15.5 associated with Beckwith-Wiedemann syndrome. The cluster comprises approximately 1 Mb of DNA, contains at least eight imprinted genes and is demarcated by the two maternally expressed genes Tssc3 (Ipl) and H19 which are directly flanked by the non-imprinted genes Nap1l4 (Nap2) and Rpl23l (L23mrp), respectively. We also localized Kcnq1 (Kvlqt1) and Cd81 (Tapa-1) between Cdkn1c (p57(Kip2)) and Mash2. The mouse Kcnq1 gene is maternally expressed in most fetal but biallelically transcribed in most neonatal tissues, suggesting relaxation of imprinting during development. Our findings indicate conserved control mechanisms between mouse and human, but also reveal some structural and functional differences. Our study opens the way for a systematic analysis of the cluster by genetic manipulation in the mouse which will lead to animal models of Beckwith-Wiedemann syndrome and childhood tumours.

Cardiac function in aneurysmal subarachnoid haemorrhage: a study of electrocardiographic and echocardiographic abnormalities.

Electrocardiographic (ECG) changes are reported frequently after subarachnoid haemorrhage (SAH). The aim of this study was to investigate the functional significance of ECG changes by echocardiographic assessment of cardiac function. Forty-five patients with intracranial aneurysms were studied. All patients had a 12-lead ECG and a two-dimensional echocardiogram. After patients with an history of chronic cardiac disease (n = 4) were excluded, only four patients were found to have wall motion abnormalities. These patients had only minor ECG abnormalities, but severe neurological dysfunction. Conversely, patients with other ECG abnormalities including the deep inverted T waves associated usually with SAH, had normal echocardiograms. We conclude that the ECG is not an accurate predictor of myocardial function after SAH and that myocardial dysfunction is related more closely to severity of neurological condition.

Breath-by-breath measurement of oxygen consumption and FIO2-FEO2 with increased oxygen demand.

Continuous on-line breath-by-breath measurement of pulmonary gas exchange was used to monitor the increase in oxygen uptake (VO2) and carbon dioxide excretion (VCO2) induced by the oxidative phosphorylation uncoupling agent 2, 4-dinitrophenol (DNP) in 10 dogs. With incremental doses of DNP totaling 5 mg/kg, the continuously monitored VO2 increased within 2-3 min after the first injection of the drug. VCO2 showed a similar response 4-6 min after the first injection. Temperature increase due to the pharmacological oxidative phosphorylation uncoupling required 20-30 min for a discernible change at this dose. This study also demonstrated a modified and compromised response to the drug in dogs where oxygen delivery was limited by mechanical ventilation.

Subarachnoid clonidine reduces spinal cord blood flow and glucose utilization in conscious rats.

The authors investigated the spinal blood flow and metabolic effects of subarachnoid clonidine in conscious rats prepared with chronically implanted subarachnoid catheters. For the blood flow experiments, rats received saline (n = 7) or clonidine 20 nmol (7 micrograms; n = 6), 100 nmol (27 micrograms; n = 5), or 400 nmol (107 micrograms; n = 7) intrathecally. Another group of rats received clonidine 400 nmol intravenously (n = 4). Spinal glucose utilization was measured in rats that received either saline (n = 5) or clonidine 100 nmol (n = 5) intrathecally. Spinal cord blood flow (SCBF) and glucose utilization were measured in five gray and three white matter areas of lumbar spinal cord 15 min after drug administration with the autoradiographic iodo-[14C]-antipyrine and 2-[14C]-deoxyglucose methods, respectively. Physiologic differences between the groups were minor. Rats in the blood flow experiments that received clonidine 100 nmol had a slightly lower arterial PO2 level (70 +/- 1 vs. 82 +/- 3 mmHg; P less than 0.05), whereas those in the glucose utilization group were mildly hypocarbic (PCO2 27 +/- 1 vs. 32 +/- 2 mmHg; P less than 0.01) relative to control animals. Only animals that received 400 nmol clonidine intrathecally had significant analgesia, as assessed by the tail-flick test. One control animal for the metabolism experiments was technically unsatisfactory and was excluded from data analysis. Subarachnoid clonidine reduced both SCBF and glucose utilization. In spinal gray matter, the largest decreases in flow (32-44%; P less than 0.01) occurred with 20 nmol clonidine, whereas flow decreased least (12-27%) with the 400-nmol dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous opportunistic and systematic screening for hypertension with computer help: analysis of non-responders.

For two years an office computer was used to identify patients to prompt for opportunistic screening and call for systematic screening. After the two years 92% of patients on the list had had blood pressure readings recorded within the previous five years, of which 34% resulted from special prompts and 22% from screening letters. Those who failed to respond to letters were sent questionnaires, and their records were compared with those of screened patients. With the help of a microcomputer it is practicable to sustain a continuous screening rate of between 90% and 95%.

Developing a practice formulary as a byproduct of computer controlled repeat prescribing.

We use our office computer to record and issue repeat prescriptions. Each month we look at a printout to see how many times a drug has been prescribed, with the goal of limiting our practice formulary. We have reduced by more than 10% the range of drugs that we use in the practice and have the possibility of knowing dose ranges, actions, interactions, and side effects of all the drugs used in the practice.

Simultaneous computer-calculated carbon dioxide and oxygen direct Fick and dye dilution measurements of cardiac output in dogs.

Cardiac output was measured by both indocyanine green dye dilution and the direct Fick method using computer-calculated values for oxygen consumption and carbon dioxide excretion in eight mechanically ventilated dogs anesthetized with pentobarbital, with either tubocurarine or succinylcholine intravenous drip for neuromuscular relaxation. Sequential measurements were made during the anesthesia and in response to pharmacologically induced increased cardiac output using doxapram hydrochloride (1.5 mg/kg) given intravenously. The purpose of this project was to investigate the accuracy and reliability of the direct Fick measurements during anesthesia using computer-calculated measurements of pulmonary gas exchange and, since, these measurements have not been reported in detail previously, to establish tentative control values for future projects. The correlation of dye and direct Fick measurements of cardiac output during the first hour after induction of anesthesia was very good (r = 0.85 for all dye-carbon dioxide Fick values; r = 0.83 for all dye-oxygen Fick values.

Noninvasive measurement of pulmonary gas exchange during general anesthesia.

Expired gas flow volume (VE), carbon dioxide excretion (Vco2) and oxygen consumption (Vo2) were measured continuously for 2-minute periods at 15-minute intervals during at least 75 minutes of general anesthesia and surgery in clinical patients. Analog tape-recorded outputs from an infrared CO2 analyzer, from a rapid polarographic O2 analyzer, and from a pneumotachograph were subsequently processed by a general purpose digital computer. Values for VE, VCO2, and VO2 in a group of 50 normal paralyzed endotracheally intubated women with balanced N2O-O2-fentanyl anesthesia for lower abdominal surgery compare favorably with the few published reports of similar measurements. The measured response to anesthesia and surgery in most patients included a progressive increase in O2 uptake and a concurrent but not necessarily simultaneous decrease in CO2 output with a consequent decreased respiratory gas exchange ratio (RE).