Interleukin-8 (IL-8), melanoma growth-stimulatory activity, and neutrophil-activating peptide selectively mediate priming of the neutrophil NADPH oxidase through the type A or type B IL-8 receptor

The capacity of neutrophils to generate superoxide (O-2) can be enhanced by prior exposure to "priming" agents such as interleukin-8 (IL-8), melanoma growth-stimulatory activity (MGSA), and neutrophil-activating peptide (ENA-78). The biological effects of these chemokines are mediated by at least two distinct receptors: type A (IL-8-RA) and type B (IL-8-RB). Using neutralizing monoclonal antibodies to IL-8-RA and IL-8-RB, we have investigated the contribution each receptor makes to the priming response. Preincubation with IL-8, MGSA, or ENA-78 enhanced the ability of neutrophils to generate O-2 following stimulation with the bacterial peptide formyl-Met-Leu-Phe. The priming effect of IL-8 was eliminated by an anti-IL-8 monoclonal antibody (mAb) that is known to bind IL-8 with high affinity and prevent receptor occupancy. Incubation of neutrophils with a neutralizing mAb specific for IL-8-RA blocked IL-8-induced priming but had no effect on priming by MGSA or ENA-78. In contrast, treatment with a neutralizing mAb specific for IL-8-RB failed to inhibit the priming effect of IL-8 but blocked both MGSA and ENA-78-induced priming. These observations indicate that the priming effect of IL-8 on the neutrophil respiratory burst is predominantly mediated via IL-8-RA, whereas priming by MGSA and ENA-78 is mediated by IL-8-RB.     

Osteolytic form of Paget's disease. Differential diagnosis and pathogenesis

Of fourteen patients with Paget's disease for whom adequate roentgenograms and pathological material were available, six had lesions showing significant or predominant osteolysis. Based on a study of these six patients and a review of the literature, the following mechanisms were identified as causes of the so-called osteolytic type of the disease: (1) an "early" destructive Paget's lesion; (2) "advanced" Paget's disease with secondary degenerative changes; (3) "seeding" of an independent osteolytic lesion, particularly tumor in pre-existing Paget's disease; (4) sarcomatous transformation; and (5) immobilization after fracture. An osteolytic lesion in a patient without other bone disease may be due to Paget's disease, while an associated lytic lesion may be the result of a variety of conditions. Accurate pathological diagnosis is essential.     

Jejunal atresia with absent mesentery and a helical ileum

Of 59 infants with jejunoileal atresia, seven presented with absence of mesentery, the main superior mesenteric artery ceasing to exist beyond the origin of the right colic or ileocolic artery, and a helical ileum. This distinctive form of jejunal atresia has been recognized with increasing frequency in recent years. Distal to the atresia, the small bowel receives its blood supply retrograde from an artery derived from the ileocolic or right colic arcades, and the ileum coils around its nutrient artery in an "apple peel" or "Christmas tree" deformity. The first three patients in this report died. The lastion, but they recovered as their malabsorption gradually disappeared. The treatment includes resection of the dilated bowel, as in other atresias. Resection of part of the distal bowel may be required for additional atresias or for poor vascularity with questionable viability. Postoperative malabsorption generally requires intravenous hyperalimentation.     

Fibromuscular dysplasia of the superior mesenteric artery and coexisting cerebral berry aneurysms

Fibromuscular dysplasia of the systemic artery and cerebral "berry" (saccular) aneurysm are nonatheromatous lesions of uncertain etiology. The coexistence of these vascular disorders in the individual reported here is unusual and may provide a possible explanation of their pathogenesis.     

Admittance tympanometry in otosclerotic ears

Twenty-eight surgically confirmed otosclerotic ears were evaluated to determine whether tympanometric admittance measurements could differentiate otosclerosis from a normal population. Subjects were tympanometrically measured at test conditions B220, B660, G220 and G660 Hz. When comparing mean curve peak amplitude to normative standards, 20 ears showed significantly low admittance tympanograms. Further investigation revealed no significant differences in curve width or pressure of the curve peak. Of the remaining eight otosclerotic ears, all produced diphasic "W"-notched tympanometric configurations. Diagnostic implications and physiological hypothesis are discussed.     

A general computational method for converting normal spectra into derivative spectra

The mathematical problem of converting a normal spectrum into the corresponding first- and second-derivative spectra is formulated as an integral equation of the first kind. Tikhonov regularization is then applied to solve the spectral conversion problem. The end result is a set of linear algebraic equations that takes in as input the original spectrum and produces as output the second-derivative spectrum, which is then integrated to yield the first-derivative spectrum. Noise amplification is kept under control by adjusting the regularization parameter (guided by generalized cross-validation) in the algebraic equations. The performance of this procedure is demonstrated by applying it to different types of spectral data taken from the literature.     

The retention of large particles (greater than 2mum) in fibrous filters

A simple method of testing fibrous filters to obtain the grade efficiency curve in the particle size range 2-22 mum is described. Dust collected by the method has been used to measure the retention efficency of model filters and it is shown that there is a maximun in the grade efficency curve. The influence of relative humidity on filter behaviour has been investigated. It is shown that the efficiency of filtration in high particle inertia systems increases with increasing relative humidity. It is considered that the reason for this is an increase in particle-fiber adhesion force.     

A constrained neural network Kalman filter for price estimation in high frequency financial data

In this paper we present a neural network extended Kalman filter for modeling noisy financial time series. The neural network is employed to estimate the nonlinear dynamics of the extended Kalman filter. Conditions for the neural network weight matrix are provided to guarantee the stability of the filter. The extended Kalman filter presented is designed to filter three types of noise commonly observed in financial data: process noise, measurement noise, and arrival noise. The erratic arrival of data (arrival noise) results in the neural network predictions being iterated into the future. Constraining the neural network to have a fixed point at the origin produces better iterated predictions and more stable results. The performance of constrained and unconstrained neural networks within the extended Kalman filter is demonstrated on "Quote" tick data from the $/DM exchange rate (1993-1995).