Perpest model,a case-based reasoning approach to predict ecological risks of pesticides

The PERPEST model is a model that predicts the ecological risks of pesticides in freshwater ecosystems. This model simultaneously predicts the effects of a particular concentration of a pesticide on various (community) endpoints. In contrast to most effect models, PERPEST is based on empirical data extracted from the literature. This model is based on case-based reasoning, a technique that solves new problems (e.g., what is the effect of pesticide A?) by using past experience (e.g., published microcosm experiments). The database containing the past experience has been constructed by performing a review of freshwater model ecosystem studies. This review assessed the effects on various endpoints (e.g., community metabolism, phytoplankton, and macroinvertebrates) and classified them according to their magnitude and duration. The PERPEST model searches for analogous situations in the database, based on relevant (toxicity) characteristics of the compound. This allows the model to predict effects of pesticides for which no effects on a semifield scale have been published. The PERPEST model results in a prediction showing the probability of classes of effects (no, slight, or clear effects, plus an optional indication of recovery) on the various grouped endpoints. This paper discusses the scientific background of the model as well as its strengths, limitations, and possible applications.     

Spinocerebellar ataxias in the Netherlands: prevalence and age at onset variance analysis

BACKGROUND: International prevalence estimates of autosomal dominant cerebellar ataxias (ADCA) vary from 0.3 to 2.0 per 100,000. The prevalence of ADCA in the Netherlands is unknown. Fifteen genetic loci have been identified (SCA-1-8, SCA-10-14, SCA-16, and SCA-17) and nine of the corresponding genes have been cloned. In SCA-1, SCA2, SCA3, SCA6, SCA7, SCA-12 and SCA-17 the mutation has been shown to be an expanded CAG repeat. Previously, the length of the CAG repeat was found to account for 50 to 80% of variance in age at onset. Because of heterogeneity in encoded proteins, different pathophysiologic mechanisms leading to neurodegeneration could be involved. The relationship between CAG repeat length and age at onset would then differ accordingly. METHOD: Based on the results of SCA mutation analysis in the three DNA diagnostic laboratories that serve the entire Dutch population, the authors surveyed the number of families and affected individuals per SCA gene, as well as individual repeat length and age at onset. Regression analysis was applied to study the relationship between CAG repeat length and age at onset per SCA gene. The slopes of the different regression curves were compared. RESULTS: On November 1, 2000, mutations were found in 145 ADCA families and 391 affected individuals were identified. The authors extrapolated a minimal prevalence of 3.0 per 100,000 (range 2.8 to 3.8/100,000). SCA3 was the most frequent mutation. CAG repeat length contributed to 52 to 76% of age at onset variance. Regression curve slopes for SCA-1, SCA2, SCA3, and SCA7 did not differ significantly. CONCLUSIONS: The estimated minimal prevalence of ADCA in the Netherlands is 3.0 per 100,000 inhabitants. Except for SCA6, the relationship between age at onset and CAG repeat expansion does not differ significantly between SCA-1, SCA2, SCA3, and SCA7 patient groups in our population, indicating that these SCA subtypes share similar mechanisms of polyglutamine-induced neurotoxicity, despite heterogeneity in gene products.     

Ectopic posterior pituitary lobe and periventricular heterotopia: cerebral malformations with the same underlying mechanism?

BACKGROUND AND PURPOSE: Ectopic posterior pituitary lobe often occurs in children with growth hormone deficiency and is part of the spectrum associated with septo-optic dysplasia. Some cases of septo-optic dysplasia are caused by homozygous mutations in the homeobox gene HESX1, whereas heterozygous mutations are associated with milder phenotypes. To date, HESX1 is the only gene associated with ectopic posterior pituitary lobe. We describe an association between ectopic posterior pituitary lobe and periventricular heterotopia in four children without classic features of septo-optic dysplasia and suggest possible mechanisms on the basis of a review of pituitary embryology and recent molecular genetic advances. METHODS: Among 20 children with ectopic posterior pituitary lobe, four had associated periventricular heterotopia. We herein review the clinical and MR imaging findings of these four children. Mutation screening of HESX1 was performed in two. RESULTS: All four children had growth hormone deficiency. None had visual or neurologic disturbances. MR images showed a range of pituitary appearances, with scattered discrete periventricular heterotopia in each case. Other abnormalities were limited to small suprasellar lipomas and callosal dysgenesis. A heterozygous HESX1 mutation was present in one case. CONCLUSION: The coexistence of ectopic posterior pituitary lobe and periventricular heterotopia suggests they have a common underlying genetic basis that is due to gene expression at different locations and stages of development. The presence of a heterozygous HESX1 mutation in one case suggests this gene is important in the development of both ectopic posterior pituitary lobe and periventricular heterotopia and supports their place in the spectrum of septo-optic dysplasia. Further analysis of HESX1 and other genes in related developmental pathways will elucidate their roles in the development of both malformations.     

Dexamethasone decreases the pro- to anti-inflammatory cytokine ratio during cardiac surgery

Background. Cytokines regulate inflammation associated withcardiopulmonary bypass (CPB). Pro-inflammatory cytokines maycause myocardial dysfunction and haemodynamic instability afterCPB, but the release of anti-inflammatory cytokines is potentiallyprotective. We studied the effects of dexamethasone on pro-and anti-inflammatory cytokine responses during coronary arterybypass grafting surgery. Methods. Seventeen patients were studied: nine patients receiveddexamethasone 100 mg before induction of anaesthesia (group1) and eight patients acted as controls (group 2). Plasma levelsof tumour necrosis factor (TNF)-     

Survey of the definition and screening of neonatal hypoglycaemia in Australia

Objective : To determine the approach to identifying neonatal hypoglycaemia and the definition of neonatal hypoglycaemia used by neonatal paediatricians in Australian Level 3 neonatal intensive care units (NICU).
Methodology : A questionnaire was sent to the 101 neonatal paediatricians in the 22 Level 3 NICU in Australia asking their method of screening for, and definition of, neonatal hypoglycaemia.
Results : Responses were received from 70 neonatal paediatricians, including all 22 directors. A bedside glucose meter is used in 19 of 22 NICU to screen for hypoglycaemia, whilst one NICU uses a glucose analyzer and another NICU uses a visual colour comparison method. One NICU does not screen, but has blood glucose measured in a satellite laboratory. If the screening method suggests hypoglycaemia, 62 of 63 neonatal paediatricians proceed to blood glucose determination in a laboratory, mostly using plasma samples. Based on the laboratory measurement, the definition of neonatal hypoglycaemia ranged from <1.1 to 3.0 mmol/L.
Conclusions : The majority of neonatal paediatricians in Australian NICU screen for neonatal hypoglycaemia using a bedside glucose meter. There is a wide range in the definition of neonatal hypoglycaemia from <1.1 to 3.0mmol/L.     

R. Daudt, G. L. Von poser, G. Neves and S. M. K. Rates, 'Screening for the antidepressant activity of some species of hypericum from south Brazil'. Phytotherapy research14(5) 2000, 344-346

The original article to which this Erratum refers was published in Phytotherapy Research 14(5) 2000, 344-346. Following the publication of this paper in the August 2000 issue of Phytotherapy Research (14(5):344-346), it has come to our attention that there is a misleading statement regarding conclusions cited from the work of Butterweck et al. 1998. The discussion in the recent PTR paper states that those authors are 'in favour of the hypothesis that the antidepressant activity is due to the hypericin only'. We wish to make it clear that this is not the case, and the Butterweck paper actually concludes that 'both naphthodianthrones must be considered as active constituents of the crude extract of H. perforatum. However, previous studies indicate that the other consitutuents of the crude drug also have activity'. The authors apologize for this error and are happy to correct it.     

Oral rehydration solutions in gastroenteritis before and after admission to hospital

Two recent studies published in this Journal draw attention to deficiencies in treatment of children with acute infectious diarrhoea in Australia.^1,2 There is now no doubt that use of correctly constituted oral rehydration solutions provides optimal therapy for affected children unless circulation is compromised, vomiting is more than average, or complicating disorders are present. In the vast majority of cases, these complications do not occur. A high proportion of the childhood population experiences gastroenteritis at some time. It is known that 50% of Melbourne children require medical attention for rotavirus infection alone during their first 3 years of life, although less than 5% require admission.     

Anterior open bite: the role of the infra-alveolae in its diagnosis and treatment

Anterior open-bites may be skeletal, alveolar or mixed. The infra-alveolae is always due to a postural or functional muscular cause and the clinical examination plays an important part in the diagnosis. Delaire's cephalometric analysis can define the type of infra-alveolae. In view of their aetiology, the infra-alveolae require functional re-education, although glossectomy and multiple bands therapy may also be useful.     

Cutaneous manifestations of malignant mesothelioma of the tunica vaginalis testis

A rare case of cutaneous invasion of a malignant mesothelioma of the tunica vaginalis testis is described in a 86-year-old man. There was no anamnestic evidence of asbestos exposure.