Analysis of electrical phenomena accompanying the growth of Neurospora crassa hyphae: theory and experiment

To describe electrical phenomena observed in growth of Neurospora crassa hyphae, a theoretical model was developed considering the hypha as a one-dimensional electric cable with non-uniform longitudinal distribution of current sources reflecting the activity of proton pumps. A profile of the density of the pump current along the hypha is proposed, at which the results of simulation quantitatively coincide with the results of physiological experiments. The model values of energy coupling in the growth zones were estimated. The experimental dependence of the elongation rate of regenerating apical hypha fragments on their lengths was determined. Based on the comparison of these experimental results with the results of analysis of the model, the contribution of the axial metabolite transport, from the distal parts of the hypha to the apical part, to the dynamics of the apical cell growth was estimated. The possibility of evaluating the intensity of high-molecular-weight syntheses and/or accumulation of substances in granules was demonstrated. The growth rate of the regenerating hypha fragments was shown to correlate with the electric current flowing into the apical fragment 0.2-mm in length.     

Occupational exposures and amyotrophic lateral sclerosis. A population-based case-control study

This population-based case-control study was conducted in three countries in western Washington State to evaluate associations between workplace exposures and the risk of amyotrophic lateral sclerosis (ALS). Cases (n = 174) were all newly diagnosed with ALS by neurologists during 1990-1994, and controls (n = 348), who were matched according to age (+/-5 years) and sex, were identified via random-digit dialing or Medicare enrollment files. Four industrial hygienists blindly assessed detailed lifetime job histories for exposures to metals, solvents, and agricultural chemicals. Case-control comparisons were made for jobs held between 15 years of age and 10 years prior to the cases' dates of diagnosis. After adjustment for age and education, ever exposure to agricultural chemicals was associated with ALS (odds ratio (OR) = 2.0, 95% confidence interval (CI) 1.1-3.5); this association was observed separately in men (OR = 2.4, 95% CI 1.2-4.8) but not in women (OR = 0.9, 95% CI 0.2-3.8). Among men, the odds ratio for low exposure to agricultural chemicals (below the median level for exposed controls) relative to no exposure was 1.5 (95% CI 0.4-5.3), and for high exposure, it was 2.8 (95% CI 1.3-6.1) (p for trend = 0.03). Similar analyses based on the panel's assessment of exposures to metals and solvents showed no associations. These findings suggest an association between ALS and agricultural chemicals in men.     

The incidence and characteristics of the clinical picture of recurrent myocardial infarct in the rural population

As many as 3033 patients with myocardial infarction residing in rural areas were kept under observation. In this population, myocardial reinfarction (MRI) was diagnosed in 411 subjects, with 78.8% having had it for 4 years. Those MRI patients ranging between 51 to 60 years showed the greatest prevalence (44.3%). The ratio of micro- to macrofocal (through-and-through) MRI was 1:3, that of males to females 9:1. Microfocal MRI was commonly associated with a pain-free variant of the disease (23.5%) with low frequency of thromboembolic complications (3.1%). Every fifth patient with macrofocal (through-and-through) renecrosis presented with aneurysm of the heart. In a 10-year and longer follow-up, mortality from MRI was 43.6 percent among patients with macrofocal MRI, while deaths attributable to microfocal MRI were estimated to be 28.9 percent. High mortality rates suggest great severity of illness and low efficacy of the drug therapy adopted.     

The impact of child support on cognitive outcomes of young children

There are two types of homologous enzymes catalysing the dismutation of the superoxide radical--Cu-Zn superoxide dismutases, and manganese or iron superoxide dismutases. In the latter two forms there is a high percentage of identity in the primary structures, and the tertiary structures are very similar particularly in the areas of the active site and in the residues responsible for the formation of the dimer. The quaternary structure of the dimer is also highly conserved. However, it has been found that despite this conservation there is strong metal ion specificity and many enzymes in the family will only be active if the correct metal ion is present. The purpose of this study has been to analyse solved X-ray structures for interactions common in both the manganese and iron forms and those that are specific to each, which may indicate reasons for the metal ion specificity. Initial analysis points to the probability that it is a combination of a number of residues, and not necessarily the same ones in every instance, which confer the specificity. In addition we have identified some anomalies in the currently available Fe/MnSOD structures which may require further remodelling and refinement.     

A 2-methyleneoxetane analog of orlistat demonstrating inhibition of porcine pancreatic lipase

The 2-methyleneoxetane analog 2 of orlistat (OLS, 1) has been synthesized and tested against porcine pancreatic lipase (PPL). Despite the loss of the carbonyl group, a potential site for hydrogen bonding interaction with the enzyme and the key element in the acylation by OLS, 2 has activity comparable to 1.     

Successful delayed thrombolytic therapy in a patient with massive pulmonary embolism

Pica is the persistent, culturally and developmentally inappropriate ingestion of non-nutritive substances (DSM-IV). AB is a 75-year-old lady with a 40-year history of schizophrenia and a 20-year history of pica who, at emergency laparotomy, had 175.32 Pounds of loose change in her stomach. Although pica has been reported to coexist with schizophrenia, she had had no positive symptoms of schizophrenia for at least 20 years. She has CT evidence of fronto-tempotal atrophy most marked on the left in the temporal lobe and on the right in the frontal lobe. Pica has been found to be related to cognitive deficits and hyperoral behaviour to temporal lesions. Neuropsychological testing reveals deficits closely related to these changes.     

The affinity of cholera toxin for Ni2+ ion

Cholera toxin (CT) was shown to bind to immobilized Ni2+ ion. The affinity of CT for the complex required the presence of the Ni2+ ion, since CT was unable to bind in its absence. Binding was mediated by the B-subunit (CTB) as both CT and CTB bound to the resin, but not the A-subunit (CTA). Binding was reversible in the presence of imidazole and suggested that the affinity of CT for the Ni2+ ion was mediated by His residues. The heat-labile enterotoxin of Escherichia coli (LT), which is closely related to CT, was unable to bind to the Ni2+ ion. Comparison of amino acid sequences revealed the presence of three His residues in CT (positions 13, 57 and 94), but only one in LT (position 57). To confirm that the residues at positions 13 and 94 of CTB were responsible for the binding, they were changed to residues found in LTB. Changing His13-->Arg completely abrogated the ability of CTB to bind to Ni2+ ion. In contrast, the mutation of His 94-->Asn reduced, but did not abrogate, the ability of CTB to bind to Ni2+ ion. Based on calculated interatomic distances, it is unlikely that His13 and His94 are part of the same complex. There appear to be two separate binding sites, with the principal site involving His13 and a much weaker site involving His94. This latter site can only participate in binding if the complex involving His13 has formed.     

Using the ALPHA form in practice to assess antenatal psychosocial health. Antenatal Psychosocial Health Assessment

BACKGROUND: The assessment of the psychosocial health of pregnant women and their families, although recommended, is not carried out by most practitioners. One reason is the lack of a practical and evidence-based tool. In response, a multidisciplinary group created the Antenatal Psychosocial Health Assessment (ALPHA) form. This article describes the development of this tool and experience with it in an initial field trial. METHODS: A systematic literature review revealed 15 antenatal psychosocial risk factors associated with poor postpartum family outcomes of woman abuse, child abuse, postpartum depression, marital/couple dysfunction and increased physical illness. The ALPHA form, incorporating these risk factors, was developed and refined through several focus groups. It was then used by 5 obstetricians, 10 family physicians, 7 midwives and 4 antenatal clinic nurses in various urban, rural and culturally diverse locations across Ontario. After 3 months, these health care providers met in focus groups to discuss their experiences. A sample of pregnant women assessed using the ALPHA form were interviewed about their experience as well. Results were analysed according to qualitative methods. RESULTS: The final version of the ALPHA form grouped the 15 risk factors into 4 categories--family factors, maternal factors, substance abuse and family violence--with suggested questions for each area of enquiry. The health care providers uniformly reported that the form helped them to uncover new and often surprising information, even when the women were well known to them. Incorporating the form into practice was usually accomplished after a period of familiarization. Most of the providers said the form was useful and would continue to use it if it became part of standard care. The pregnant women in the sample said they valued the enquiry and felt comfortable with the process, unless there were large cultural barriers. INTERPRETATION: The ALPHA form appears to be an important tool in assessing psychosocial health in pregnancy and to be readily integrated into practice. More study is required to quantify the number of risks identified and resources used, to determine the form's reliability and validity and, ultimately, to assess the effect of its use on postpartum outcomes.