Multiple peaks in high-performance liquid chromatography of proteins. beta-Lactoglobulins eluted in a hydrophobic interaction chromatography system

The hypothesis of Geisler (Brain Res. 212 (1981) 198-201), in which the different spontaneous-rate classes of primary auditory neurons were accounted for by the different sizes of uniquantal EPSPs relative to the gap between resting membrane and threshold potentials, was represented with an expanded model which included relative refractory effects. The spike rates generated by the expanded model, when plotted vs. estimated sound level, are qualitatively similar to those of experimentally obtained rate-level curves. The hypothesis is also consistent with recent ultrastructural data which suggest that average quantal-release rates for any particular primary auditory neuron are inversely related to its spontaneous rate. The model's recovery processes following spike generation (hazard functions) are also similar to those observed experimentally.     

Compositional constraints in the extremely GC-poor genome of Plasmodium falciparum

We have analyzed the compositional properties of coding (protein encoding) and non-coding sequences of Plasmodium falciparum, a unicellular parasite characterized by an extremely AT-rich genome. GC% levels, base and dinucleotide frequencies were studied. We found that among the various factors that contribute to the properties of the sequences analyzed, the most relevant are the compositional constraints which operate on the whole genome.     

Low molecular weight heparins. Implications in anesthesia and resuscitation

Low molecular weight heparins are a group of drugs that have only recently been introduced in clinical practice. The are widely used for prophylaxis in thromboembolic disease and are being employed increasingly to treat established venous thrombosis. One way in which these drugs are often used is for prophylaxis in the perioperative period for patients at high risk of developing venous thromboembolism, and the anesthesiologist must therefore be familiar with the main aspects of this application. We review pharmacological characteristics of these drugs as well as the literature on low molecular weight heparins, stressing points of main interest to the anesthesiologist and intensive care recovery unit specialist, namely adverse effects (mainly bleeding) and the implications that use of low molecular weight heparin will have on choice of anesthetic (in particular the dilemma of whether to use local/regional anesthesia).     

Regional chemotherapy of liver tumors

In the absence of adequate autogenous vein for tibial artery bypass in limb salvage surgery, the use of prosthetic grafts with a distal anastomotic vein cuff or patch has shown promising results. Here, we describe how the Florester Internal Vessel Occluder (Meadox UK, Bedfordshire, UK) can facilitate the construction of a distal anastomotic vein cuff.     

Nitric oxide synthase-immunoreactive neurons in human and porcine respiratory tract

The presence of nitric oxide synthase (NO-synthase), the enzyme responsible for the production of nitric oxide (NO) from L-arginine, is shown immunocytochemically in the intrinsic neurons of the human and porcine respiratory tract. NO-synthase immunoreactivity is demonstrated in a subpopulation of neurons of the microganglia present in the wall of the extra- and intrapulmonary bronchi as well as in the hilar region of the lung in relation to blood vessels. The immunostaining was also found in some nerve fibers of the respiratory nervous system. Human and porcine lung gave similar results. The possible involvement of NO in the nonadrenergic noncholinergic (NANC) nervous regulation of the lung is discussed.     

Pharmacological distribution diagrams: a tool for de novo drug design

BACKGROUND: There is no empirical data available on attitudes concerning AIDS and habits towards HIV infected patients of physicians in general or private practice. In this study results of a self-evaluation are presented. METHODS: 178 physicians working with out-patients in different medical fields were randomly selected for a cross sectional study and interviewed using a standardised questionnaire. RESULTS: 89% think that they are sufficiently informed about AIDS (in the USA 20%). They regarded the risk of infection to be lower than the Anglo-American physicians. They believed there is a lack of interchange of information between colleagues regarding the degree of infectiousness of referred patients. A third of the physicians fear that other patients will go elsewhere if they find out that their physician is treating AIDS patients. 54% would hold special clinic sessions for HIV-patients outside the normal schedule for practice times. 89% believed that HIV patients were partly to blame for their illness. CONCLUSIONS: Although the physicians recognise the problem of HIV-infection, they partly deny the real necessities and facts. A reason for this could be the emotions underlying the general attitude to everything pertaining to HIV-disease. Attitudes to HIV-disease and the dealing with it in daily practice must be considered on the basis of individual emotional motives.     

A major isoform of the maize plasma membrane H(+)-ATPase: characterization and induction by auxin in coleoptiles

The plasma membrane (PM) H(+)-ATPase has been proposed to play important transport and regulatory roles in plant physiology, including its participation in auxin-induced acidification in coleoptile segments. This enzyme is encoded by a family of genes differing in tissue distribution, regulation, and expression level. A major expressed isoform of the maize PM H(+)-ATPase (MHA2) has been characterized. RNA gel blot analysis indicated that MHA2 is expressed in all maize organs, with highest levels being in the roots. In situ hybridization of sections from maize seedlings indicated enriched expression of MHA2 in stomatal guard cells, phloem cells, and root epidermal cells. MHA2 mRNA was induced threefold when nonvascular parts of the coleoptile segments were treated with auxin. This induction correlates with auxin-triggered proton extrusion by the same part of the segments. The PM H(+)-ATPase in the vascular bundies does not contribute significantly to auxin-induced acidification, is not regulated by auxin, and masks the auxin effect in extracts of whole coleoptile segments. We conclude that auxin-induced acidification in coleoptile segments most often occurs in the nonvascular tissue and is mediated, at least in part, by increased levels of MHA2.