Potent bifunctional anticoagulants: Kunitz domain-tissue factor fusion proteins

A strategy to design potent antagonists of human coagulation factor VIIa (FVIIa) by linking two proteins that independently inhibit activity and bind at separate, nonoverlapping sites is presented. A bifunctional inhibitor (KDTF5), comprising a Kunitz-type domain engineered to inhibit the FVIIa active site and a soluble tissue factor (TF) variant that is defective as a cofactor for factor X (FX) activation, was developed from structure-based modeling of a ternary FVIIa-Kunitz domain-TF complex. KDTF5 inhibited FVIIa-dependent FX activation with a Ki* of 235 +/- 45 pM, a 193-fold and 398-fold increase in potency compared to the TF variant and Kunitz domain individually. Similarly, KDTF5 was a more potent anticoagulant in vitro compared to either inhibitory domain alone. The results demonstrate the harnessing of a macromolecular chelate effect by fusing two inhibitory ligands that bind a target at spatially distinct sites.     

In situ interleukin 5 gene expression in pediatric Crohn's disease

BACKGROUND: Eosinophils contribute to the intestinal inflammatory infiltrate in Crohn's disease (CD). Eosinophilic infiltration occurs early in Crohn's recurrences, and a release of eosinophil cationic proteins has been observed in active CD. The proliferation, differentiation, and activation of eosinophils are highly dependent on the cytokine interleukin 5 (IL5). In the present study, we used in situ hybridization (ISH) to investigate the expression of the IL5 gene in intestinal specimens from patients with CD. METHODS: We studied 14 intestinal samples from eight children who had undergone ileocolectomy for advanced CD. The samples were examined for the intensity of the inflammatory infiltrate. Normal pediatric intestine specimens served as controls. In situ hybridization was performed on frozen tissue using radiolabeled IL5 mRNA probes. RESULTS: Positive signal with the IL5 antisense probe was observed within numerous cells infiltrating the specimens involved with CD. The number of IL5-expressing cells correlated with the histological grade of inflammation. Most of the labeled cells were eosinophils, characterized by their bilobed nuclei. Rare IL5-positive cells were detected in the control tissues. No positive signal was obtained with the IL5 sense probe. CONCLUSION: These results suggest that IL5 can be produced by eosinophils at the sites of inflammation in active CD and could be involved in the immune response by activating eosinophils, at least in part through an autocrine pathway, and perhaps by interacting with B and T cells.     

Magnetoencephalographic evidence for non-geniculostriate visual input to human cortical area V5

The aim of this study was to establish whether there is non-geniculostriate input to the extrastriate motion-sensitive area V5 in humans. Responses were measured with a SQUID neuro-magnetometer to motion stimuli presented within the blind hemifield of GY, a well-documented subject with a complete absence of the left primary visual cortical area V1. The motion stimulus was a 0.5c/deg, rapidly drifting (16Hz) achromatic sinusoidal grating. With this stimulus, the magnetic responses recorded over the temporo-parieto-occipital region in normals are well modelled by localized current sources in areas V1 and V5 (Anderson, S. J. et al., Proceedings of the Royal Society, London, Series B, 1996, 263, 423-431). As a control, evoked responses were measured to a 1.0 c/deg, stationary, photometrically isoluminant red/green sinusoidal grating. With the chromatic stimulus, the principal component of the magnetic responses recorded over the occipital pole in normals is well modelled by a current source in area V1 (Fylan, F. et al., Investigative Ophthalmology and Visual Science, 1995, 36, s1053). Both stimuli subtended 4 deg vertically by 6 deg horizontally, positioned such that the stimulus extended beyond the area of macular sparing into the lower field quadrant of the blind (or sighted) hemifield. Chromatic stimuli failed to evoked responses from GY's blind (contralateral) hemifield, consistent with there being no V1 activity in his left cortical hemisphere. However, motion stimuli did evoke responses from GY's blind hemifield, originating from a location consistent with activity in area V5. We further observed that both colour and motion stimuli evoked responses from GY's sighted (ipsilateral) hemifield. We conclude that there is non-geniculostriate input to extrastriate motion-sensitive areas in the human visual system, and that this pathway subserves the residual visual sensitivity to motion in the blind hemifield that has been demonstrated psychophysically in observer GY.     

Activating mutations for the met tyrosine kinase receptor in human cancer

Recently, mutations in the Met tyrosine kinase receptor have been identified in both hereditary and sporadic forms of papillary renal carcinoma. We have introduced the corresponding mutations into the met cDNA and examined the effect of each mutation in biochemical and biological assays. We find that the Met mutants exhibit increased levels of tyrosine phosphorylation and enhanced kinase activity toward an exogenous substrate when compared with wild-type Met. Moreover, NIH 3T3 cells expressing mutant Met molecules form foci in vitro and are tumorigenic in nude mice. Enzymatic and biological differences were evident among the various mutants examined, and the somatic mutations were generally more active than those of germ-line origin. A strong correlation between the enzymatic and biological activity of the mutants was observed, indicating that tumorigenesis by Met is quantitatively related to its level of activation. These results demonstrate that the Met mutants originally identified in human papillary renal carcinoma are oncogenic and thus are likely to play a determinant role in this disease, and these results raise the possibility that activating Met mutations also may contribute to other human malignancies.     

Differential display in primary and metastatic medullary thyroid carcinoma

Platelet-activating factor (PAF) is a mediator produced in human airways during acute and chronic inflammatory lung diseases. The levels of PAF are regulated by acetylhydrolase (AH), the enzyme that converts PAF to lyso-PAF. To determine whether AH was present in human bronchoalveolar lavage (BAL) fluid, BAL was obtained from normal donors (n = 18) and from adult patients with mild bronchial asthma (n = 15) or with lung fibrosis (n = 15). AH activity was consistently found in the cell-free BAL fluid. BAL-AH is an enzyme different from secretory phospholipase A2 and from plasma AH and erythrocyte AH. Furthermore, BAL-AH is inhibited as much as 95% by exposure to an oxygen radical-generating system (xanthine/xanthine oxidase). BAL-AH is significantly correlated with the number of BAL macrophages (rs = 0.63; p < 0.02). In addition, BAL macrophages release AH both spontaneously and after stimulation with tumor necrosis factor-alpha (TNF-alpha) (100 ng/ml). BAL-AH activity in patients with bronchial asthma (1.32 +/- 0.18 pmol of PAF converted to lyso-PAF/min) is significantly lower than that in normal donors (2.25 +/- 0.26 pmol/min; p < 0.001). In contrast, BAL-AH activity in patients with lung fibrosis (6.13 +/- 0.81 pmol/min) is higher than that found in normal donors (p < 0.01). The variations in BAL-AH activity in patients with bronchial asthma or lung fibrosis are due to a reduction and to an increase, respectively, in the number of active molecules rather than to changes in enzyme affinity. These data demonstrate that human BAL fluid contains an extracellular AH activity that inactivates PAF released in the airways. BAL-AH is secreted by alveolar macrophages and is highly sensitive to oxygen radical-induced damage. The secretion and inactivation of BAL-AH may influence the levels of this enzyme in BAL fluid during acute and chronic inflammatory lung diseases and, ultimately, regulate the proinflammatory activities of PAF in these disorders.     

Guaranteed recall of all training pairs for bidirectionalassociative memory

Necessary and sufficient conditions are derived for the weights of a generalized correlation matrix of a bidirectional associative memory (BAM) which guarantee the recall of all training pairs. A linear programming/multiple training (LP/MT) method that determines weights which satisfy the conditions when a solution is feasible is presented. The sequential multiple training (SMT) method is shown to yield integers for the weights, which are multiplicities of the training pairs. Computer simulation results, including capacity comparisons of BAM, LP/MT BAM, and SMT BAM, are presented.     

Methanol poisoning: a review and case study of four patients from central Australia

Methanol intoxication, a rare and potentially lethal form of poisoning, usually results from ingestion and occasionally inhalation of methanol. Initial symptoms of blurred vision, elongated anion gap and metabolic acidosis are typically delayed and may not at first be recognised as methanol-related complaints. Once diagnosed, treatment must be prompt and definitive. As well as general supportive care, ethanol infusion, dialysis and alkalinization from the mainstays of treatment. The cases described in this paper are compared to previous reports from other countries worldwide and contrast the variance in outcome often seen in methanol poisoning. The paper describes two tragic deaths and two lucky survivors, all of whom had consumed a cocktail of methanol and other alcoholic beverages at the same party. The ICU nurse's role in managing the methanol-intoxicated patient relies on that person's sound knowledge of the unusual biochemical reactions occurring in the body and the need to institute definitive and supportive measures to help both patient and family recover.