Predicting soil pH changes in response to application of urea and sheep urine.

Volatilization of NH3 following urea application or livestock urine deposition can result in significant loss of N to the environment. Urea hydrolysis to NH4 + results in an increase in pH, which in turn promotes transformation of NH4 + to NH3 . Accurately predicting changes in soil pH following urea (or urine) application will allow successful simulation of NH3 volatilization. The magnitude of the pH change depends on the soil's pH buffering capacity (pHBC). However, as actual pHBC values are not generally available, pHBC proxies (e.g., cation exchange capacity) have been used in modeling studies. In a 34-d laboratory incubation study, we measured soil pH and mineral N (NH4 + and NO3 - ) following a large application of urea (800 mg N kg-1 soil) to four soils with a range of pHBC values. In a second incubation, pH changes and mineral N dynamics were monitored in soil treated with sheep urine (773 mg N kg-1 soil) in the absence and presence of the nitrification inhibitor dicyandiamide. In both incubations, pH changes associated with urea hydrolysis and subsequent nitrification of NH4 + were predicted well using measured pHBC data. Our results confirmed that pHBC is base-type dependent (values greater when measured using KOH than NH4 OH). Soil pHBC is easily measured, and the use of a measured value (determined using NH4 OH) can improve model simulations of pH in the field and, potentially, lead to improved estimates of NH3 loss from animal-deposited urine patches and urea-treated soil.

Drug consumption and futile medication prescribing in the last year of life: an observational study.

Background: the last year of life for many older people is associated with high symptom burden and frequent hospitalizations. Hospital physicians have an opportunity to prioritize essential medications and deprescribe potentially futile medications. Objective: to measure medication consumption during hospitalization in the last year of life and the prevalence of potentially inappropriate medications (PIMs) at hospital discharge. Design: retrospective chart review. Setting: acute hospital. Subjects: ≥65 years, hospitalized in the last year of life. Methods: medication consumption was determined by examining hospital Medication Administration Records. PIMs were defined using STOPPFrail deprescribing criteria. Results: the study included 410 patients. The mean age of participants was 80.8, 49.3% were female, and 63.7% were severely frail. The median number of days spent in hospital in the last year of life was 32 (interquartile range 15-59). During all hospitalizations, the mean number of individual medications consumed was 23.8 (standard deviation 10.1). One-in-six patients consumed 35 or more medications in their last year. Over 80% of patients were prescribed at least one PIM at discharge and 33% had ≥3 PIMs. Lipid-lowering medications, proton pump inhibitors, anti-psychotics and calcium supplements accounted for 59% of all PIMs. Full implementation of STOPPFrail recommendations would have resulted in one-in-four long-term medications being discontinued. Conclusion: high levels of medication consumption in the last year of life not only reflect high symptom burden experienced by patients but also continued prescribing of futile medications. Physicians assisted by the STOPPFrail tool can reduce medication burden for older people approaching end of life.

Antipsychotic prescription amongst hospitalized patients with dementia.

BACKGROUND: Antipsychotic drugs are used to treat behavioural and psychological symptoms of dementia, despite significant safety concerns regarding increased risk of stroke and mortality. The numbers of patients with dementia and related behavioural symptoms being treated in acute hospitals is increasing. AIM: (i) to determine pre-admission and in-hospital prevalence of antipsychotic use in a national sample of patients with dementia and acute illness; (ii) identify reasons for antipsychotic use; (iii) assess features of the ward environment which impact on patients with dementia; (iv) determine availability of dementia-specific policies, training, appraisal and mentorship programs which influence service delivery. DESIGN AND METHODS: Four-part standardized audit in 35 public acute hospitals comprising (i) retrospective healthcare record review (n = 660); (ii) prospective assessment of ward environment (n = 77); (iii) ward organization interview with clinical managers (n = 77); (iv) hospital organisation interview with senior managers (n = 35). RESULTS: Antipsychotic drugs were prescribed to 29% of patients with dementia before hospitalization and to 41% during hospitalization; one quarter received new or additional prescriptions. Assessments for delirium (45%), dementia symptoms (39%), mood (26%), mental state (64%) and distress-provoking factors (3%) were suboptimal. Drug indications were documented in 78%. Non-pharmacological interventions were not documented. Most wards lacked environmental cues to promote orientation. Dementia-specific care pathways existed in 2 of 35 hospitals. Staff support and training programmes were suboptimal. 12% of patients were discharged with new antipsychotic prescriptions. CONCLUSION: Antipsychotic medications are commonly prescribed for hospitalized patients with dementia in Ireland. Ward environments and dementia-related governance structures are suboptimal.

Novel antibody associations in immune-mediated necrotising myopathy without inflammation.

INTRODUCTION: The patient presenting with proximal muscle weakness, elevated serum creatinine kinase and myopathic electromyography and biopsy findings has a wide differential diagnosis that includes toxic, autoimmune, paraneoplastic and congenital myopathies. Autoimmune myopathies are important to identify because they may respond to immunosuppressive therapies. METHODS: We describe two cases of immune-mediated necrotizing myopathy each associated with a novel antibody. RESULTS: Case 1 describes a progressive myopathy in a statin user. Antibodies to 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase were identified and the patient responded to steroid therapy. Case 2 describes an aggressive myopathy associated with antibodies to signal recognition particle. There was no response to steroids. Clinical improvement followed treatment with rituximab and cyclophosphamide. CONCLUSION: The identification of myositis-specific antibodies is important because they are associated with distinct clinical phenotypes and may guide the physician in terms of treatment strategies.

A national house-staff audit of medical prophylaxis in medical patients for the PREVENTion of Venous ThromboEmbolism (PREVENT-VTE).

We established a national audit to assess the thromboprophylaxis rate for venous thromoembolism (VTE) in at risk medical patients in acute hospitals in the Republic of Ireland and to determine whether the use of stickers to alert physicians regarding thromboprophylaxis would double the rate prophylaxis in a follow-up audit. 651 acute medical admission patients in the first audit and 524 in the second re-audit were recruited. The mean age was 66.5 yrs with similar numbers of male and female patients and 265 (22.6%) patients were active smokers. The first and second audits identified 549 (84%) and 487 (93%) of patients at-risk for VTE respectively. Of the at-risk patients, 163 (29.7%) and 132 (27.1%) received LMWH in the first and second audit respectively. Mechanical thromboprophylaxis was instigated in 75 (13.6%) patients in the first and 86 (17.7%) patients in the second audit. The placement of stickers in patient charts didn't produce a significant increase in the number of at risk patients treated in the second audit. There is unacceptably low adherence to the ACCP guidelines in Ireland and more complex intervention than chart reminders are required to improve compliance.

Giant atypical intraventricular meningioma presenting with visual loss in a child.

INTRODUCTION: Giant atypical intraventricular meningioma is very rare in childhood. Atypical meningiomas are characterised by an increased mitotic ratio and MIB-1 expression, and demonstrate more aggressive tumour behaviour compared with typical meningiomas. METHODS: We present the case of an 11-year-old girl who presented to the eye clinic complaining of reduced vision, and was diagnosed with a giant atypical intraventricular meningioma. RESULTS: Five years after surgical resection, there has been no recurrence of the tumour. Goldmann visual fields show a left incongruous homonymous hemianopia. CONCLUSION: This case highlights the importance of ophthalmic examination in diagnosing brain tumours in children. Such a large tumour located in the lateral ventricle may cause obstructive hydrocephalus, compression of brain tissue, seizures and loss of vision, and is potentially fatal.

Kramers' law for a bistable system with time-delayed noise.

We demonstrate that the classical Kramers' escape problem can be extended to describe a bistable system under the influence of noise consisting of the superposition of a white Gaussian noise with the same noise delayed by time tau . The distribution of times between two consecutive switches decays piecewise exponentially, and the switching rates for 0

Distribution of residence times in bistable noisy systems with time-delayed feedback.

We analyze theoretically and experimentally the residence time distribution of bistable systems in the presence of noise and time-delayed feedback. We explain various nonexponential features of the residence time distribution using a two-state model and obtain a quantitative agreement with an experiment based on a Schmitt trigger. The limitations of the two-state model are also analyzed theoretically and experimentally using a semiconductor laser with optoelectronic feedback.

Androgen suppression of GnRH-stimulated rat LHbeta gene transcription occurs through Sp1 sites in the distal GnRH-responsive promoter region.

Steroids may regulate LH subunit gene transcription by modulating hypothalamic GnRH pulse patterns or by acting at the pituitary gonadotrope to alter promoter activity. We tested direct pituitary effects of the androgen dihydrotestosterone (DHT) to modulate the rat LHbeta promoter in transfected LbetaT2 clonal gonadotrope cells and in pituitaries of transgenic mice expressing LHbeta-luciferase. The LHbeta promoter (-617 to +44 bp)-luciferase construct was stimulated in LbetaT2 cells 7- to 10-fold by GnRH. Androgen treatment had little effect on basal promoter activity but suppressed GnRH stimulation by approximately 75%. GnRH stimulation of LHbeta was also suppressed by DHT in isolated pituitary cells from male or female mice with functional nuclear ARs, but not in male littermates with mutant AR. GnRH stimulation of the LHbeta promoter requires interactions between a complex distal response element containing two specificity protein-1 (Sp1) binding sites and a CArG box, and a proximal element with two bipartite binding sites for steroidogenic factor-1 and early growth response protein-1 (Egr-1). DHT effectively suppressed promoter constructs with an intact distal response element. The distal response element does not bind AR, but AR reduces Sp1 binding to this region. Glutathione-S-transferase pull-down studies demonstrated direct interactions of AR with Sp1, which requires the DNA-binding domain of AR, and weaker interactions with Egr-1. We conclude that androgen suppression of the rat LHbeta promoter occurs primarily through direct interaction of AR with Sp1, with some possible role through binding to Egr-1. These interactions result in interference with GnRH-stimulated gene transcription by reducing cooperation between the distal and proximal GnRH response elements.

Plasmodium vivax polymorphs and Plasmodium falciparum circumsporozoite proteins in Anopheles (Diptera: Culicidae) from Belize, Central America.

Eight species of Anopheles mosquitoes from indoor/outdoor human landing collections in Belize, Central America, were examined for human Plasmodium circumsporozoite protein (CSP) using an enzyme-linked immunosorbent assay (ELISA). A total of 14 of 9,104 females tested were positive from general surveys throughout Belize and three of 11,966 were positive from a longitudinal study in Caledonia, northern Belize. ELISA results, using pooled head-thorax preparations and species-specific monoclonal antibodies directed against the circumsporozoite proteins of Plasmodium falciparum and two Plasmodium vivax polymorphs (210 and VK247), found four species reactive: Anopheles vestitipennis (3 pools), Anopheles darlingi (2 pools), Anopheles albimanus (10 pools), and Anopheles gabaldoni (2 pools). The minimum field infection rates (MFIR) for combined Plasmodium species from the general survey were 0.282% for An. vestitipennis, 0.271% for An. darlingi, 0.126% for An. albimanus, and 0.395% for An. gabaldoni. MFIRs for combined Plasmodium species from the longitudinal study in the village of Caledonia were 0.018% for both An. vestitipennis and An. albimanus and 1.66% for An. gabaldoni. Positive CSP pools were collected from the Cayo, Corozal, Orange Walk, Stann Creek, and Toledo political districts. No CSP positive pools were detected from collections in the Belize District. The study provides valuable information on the spatial distribution and species type of Plasmodium positive mosquitoes. This information, in combination with other vector data, suggest that An. vestitipennis and An. darlingi are commonly involved in malaria transmission. Additionally, these species appear to be much more efficient vectors than An. albimanus in Belize.

Assessment of Pediococcus acidilactici as a Potential Silage Inoculant.

Eighteen Pediococcus strains were screened for their potential as silage inoculants. Pediococcus acidilactici G24 was found to be the most suitable, exhibiting a short lag phase on both glucose and fructose, a rapid rate of acid production, a high sugar-to-lactate conversion efficiency, no detectable breakdown of proteins or lactic acid, and the ability to grow within a broad range of pH and temperature. When tested in laboratory silos using grass with a water-soluble carbohydrate content of 24 g/kg of aqueous extract, P. acidilactici G24 stimulated the natural Lactobacillus plantarum population and accelerated the rates of lactic acid production and pH decrease. After 6 days of fermentation, the inoculated silage exhibited a 12% decrease in ammonia nitrogen and an 11% increase in crude protein levels compared with uninoculated controls. The use of an L. plantarum inoculant at a rate of 10 bacteria per g of grass in conjunction with P. acidilactici G24 produced no additional beneficial effect. Inoculation of grass with a water-soluble carbohydrate level of 8 g/kg of aqueous extract with P. acidilactici G24 led to no acceleration in the rate of L. plantarum growth or pH decrease. However, after 7 days of fermentation the inoculated silage had a 14% lower ammonia nitrogen protein content than did uninoculated controls. The results suggest that P. acidilactici G24 may be useful as a silage inoculant for crops with a sufficiently high water-soluble carbohydrate level.

The pattern ERG in Best's disease.

The aim of this study was to assess inner retinal function in patients with Best's disease using the pattern ERG (PERG). Nine patients with Best's disease, who had good visual acuity, were studied. Five of the nine had abnormal PERGs. All five had some reduction in central visual acuity. We believe that the abnormal PERGs in these patients represents photoreceptor cell loss which is occurring at an early stage in Best's disease.

Review of alpha adrenoceptor function in the eye.

The location and function of alpha adrenoceptors in the eye are reviewed with emphasis on pharmacological agents and their role in the management of chronic simple glaucoma.

Corneal topography using computer analyzed rasterstereographic images.

This paper describes a new method for determining corneal surface detail utilizing a modified Zeiss photo slit lamp. This system projects a grid onto the cornea through a cobalt blue filter. The tear film is stained with fluorescein, causing the projected grid pattern to be visible on the corneal surface. A video image of the grid is then digitized by an image processor which calculates surface detail by evaluating the distortion of the grid lines. Information on curvature and surface detail is obtained across the full corneal surface, both the central optical axis and peripherally beyond the limbus.

Ageing and alpha 1 adrenoceptors in the iris.

This study was undertaken to determine if the age related decrease in pupil size is attributable to altered sympathetic adrenoceptor responsiveness. Log dose response curves using the selective alpha 1 agonist phenylephrine and antagonist thymoxamine showed that there is no difference in alpha 1 adrenoceptor sensitivity in the elderly and the young. Therefore age related miosis is not caused by an alteration in alpha 1 receptors with age.

Randomised double-blind trial of acyclovir (Zovirax) and adenine arabinoside in herpes simplex amoeboid corneal ulceration.

Fifty-one patients were treated in a dual-centre, double-blind comparison of acyclovir and adenine arabinoside in herpetic amoeboid (geographic) corneal ulceration. Twenty-four of the 25 patients receiving acyclovir healed in a mean time of 12.2 days, while 24 of the 26 patients treated with adenine arabinoside healed in a mean time of 11.0 days. There was no statistically significant difference between the two groups in terms of healing. A second analysis, excluding any patients who had received antiviral treatment immediately prior to entry into the study, showed that 18 of the 19 who received acyclovir healed in an average of 11.7 days and 18 of the 19 recipients of adenine arabinoside healed in a mean time of 11.2 days. Again the difference was not statistically significant.