Helicobacter pylori and stomach cancer]

The neoplasms and gastric mucosa colonization with Helicobacter pylori was studied in 40 stomachs resected for expansive (n = 20) and infiltrative (n = 20) carcinoma using Giemsa staining histological sections, histochemical reactions to oxyreductase, and urease test. In expansive carcinoma of the stomach, H. pylori was identifiable both in the tumour and surrounding gastric mucosa in 70 per cent of cases; infiltrative carcinoma appeared to be associated with gastric mucosa H. pylori in 80 per cent, whereas tumour H. pylori were recordable in 30 per cent of cases, which fact is dependent upon the histological structure of carcinoma. The role H. pylori plays in cancerogenesis is discussed.     

Bragg curve spectroscopy in a 4π geometry

Ionization counters employing Bragg curve spectroscopy have been constructed for use in a 4π geometry. These detectors compare very favorably in terms of both energy and charge resolution with small solid angle devices. These detectors have a large dynamic range because they are backed by scintillation detectors, and are thus capable of detecting and identifying particles with energies from 1 MeV/nucleon up to 200 MeV/nucleon.     

Voigt–Reuss topology optimization for structures with nonlinear material behaviors

This work is directed toward optimizing concept designs of structures featuring inelastic material behaviours by using topology optimization. In the proposed framework, alternative structural designs are described with the aid of spatial distributions of volume fraction design variables throughout a prescribed design domain. Since two or more materials are permitted to simultaneously occupy local regions of the design domain, small-strain integration algorithms for general two-material mixtures of solids are developed for the Voigt (isostrain) and Reuss (isostress) assumptions, and hybrid combinations thereof. Structural topology optimization problems involving non-linear material behaviours are formulated and algorithms for incremental topology design sensitivity analysis (DSA) of energy type functionals are presented. The consistency between the structural topology design formulation and the developed sensitivity analysis algorithms is established on three small structural topology problems separately involving linear elastic materials, elastoplastic materials, and viscoelastic materials. The good performance of the proposed framework is demonstrated by solving two topology optimization problems to maximize the limit strength of elastoplastic structures. It is demonstrated through the second example that structures optimized for maximal strength can be significantly different than those optimized for minimal elastic compliance. © 1997 John Wiley & Sons, Ltd.     

Disseminated candidiasis (moniliasis) in a dog. A case report

A case of systemic candidiasis (Candida albicans) in a 1 1/2 year old dog is reported. Clinically, the first manifestation was enlargement of a superficial inguinal lymph node. Later several peripheral lymph nodes were affected and a fistulous opening appeared, communicating with an inflammatory process in the right humerus. Necropsy revealed gross lesions in the kidneys, pancreas and multiple lymph nodes. In addition, microscopic lesions were observed in the myocardium and the bone marrow of the right humerus. The lesions, which contained large fungal colonies, were mainly granulomatous with numerous multinuclear giant and epitheloid cells, but necrosis and suppuration were also evident. The site of invasion is not known. However, a previous perianal and abdominal dermatitis, which was treated locally with antibiotics and corticoids, could possibly have been a mycotic infection.     

Chinook salmon spawning surveys in deep waters of a large,regulated river

In 1986 research divers surveyed and mapped deep-water spawning redds of fall chinook salmon (Oncorhynchus tshawytscha) in selected sites within an impounded segment of the main-stem Columbia River, Washington State, U.S.A. In velocities over 3m s^?1 and depths up to 11 m, two divers riding a manoeuvrable sled made cross-current transects communicating observations of substrate materials and deep-water spawning sites. Surface personnel tracked the position of the sled with a laser locating system that logged the information into data storage. Subsequently, the computerized data were translated into overlaying maps depicting location of redds, substrate materials, and depth contours. Deep-water spawning (>3m) occurred at most survey sites in velocities between 0.6 and 0.8m s^?1. The average depth of spawning was 6.5 m, and the maximum was 9.1 m-deeper than the depth redds can normally be detected by aerial observation (3–4 m). Deep-water spawning ranged from none to substantial in areas of near identical physical characteristics. A method for estimating abundance and density of deep-water redds, based upon the data collected with this mapping technique, is presented. This study combined with current limited information concerning deep-water spawning suggests that up to 80 per cent of the escapement of fall chinook salmon in this reach may spawn in deep water.     

A threshold and continuum of injury during active stretch of rabbit skeletal muscle

Play fighting by juvenile rats involves playful attacks directed at the partner's nape, where successful contact leads to gentle rubbing of the snout into the nape area. In addition, the recipient of such contact may defend the nape by adopting tactics of playful defense. The two most common defensive tactics in the juvenile period are evasion, where the recipient swerves or leaps away and facing defense involving rotation to supine, where the attacker is faced and its further attempts to contact the nape are blocked. An unresolved issue is whether the nape contact itself or defense by the recipient alone or in combination with nape contact, are involved in rewarding play fighting. In this study, drug-induced non-playful partners were used to test the 'motivation' for play fighting when only playful nape contact was possible. In drug-trials compared to baseline and saline trials, both neonatally androgenized females (high players) and control, oil-treated, females (low players), decreased the frequency of launching nape attacks. These results suggest that nape contact alone, in the absence of defense by the recipient, is not sufficient reinforcement for such playful activity, irrespective of the initial playfulness of the subjects. However, while nape attacks decrease, other forms of social contact, such as anogenital investigation and climbing over the partner (i.e., crawl overs), increase in frequency. These results suggest that non-playful partners are not neutral targets for normal rats. Rather, the 'non-normal' behavior of the drugged target may affect the subjects' behavior in such a way as to reduce their playfulness for reasons other than reduced reinforcement for play.     

The effect of mutation in the NS gene on the biological properties of the influenza virus

The biological properties of influenza virus strain A/PR/8/34, virulent from mice, and its variant 25A-1, obtained by hybridization with avirulent strain A/Leningrad. This reassortant 25A-1 included 7 genes of its virulent parent strain and only gene NS of the avirulent one, which contained a single mutation in position 798 (ATG=>ATA), inducing amino acid change MET=>IIe in position 100 of the polypeptide chain of protein NS2. The loss of pathogenic properties by strain A/PR/8/34 was achieved by replacing the single gene NS with an analogous mutant gene of the variant strain A/Leningrad, adapted to low temperatures. The single-gene reassortant 25A-1 thus obtained possessed, besides decreased capacity for multiplication in the lungs of mice, ts phenotype on MDCK cells, but exhibited no thermal sensitivity in cell systems of avian origin. The above-mentioned phenotypic changes in reassortant 25A-1 were due to disturbances in virus-specific protein synthesis at early and late stages, as detected in vivo and in vitro.     

Enhanced human T-cell lymphotropic virus type I expression following induction of the cellular stress response

Human T-cell lymphotropic virus type I (HTLV-I) infection is typically associated with long incubation periods between virus exposure and disease manifestation. Although viral protein expression is considered to play an important role in the pathogenesis of HTLV-I-associated diseases, limited information is known regarding host cell mechanisms that control viral gene expression. This study was designed to evaluate modulation of HTLV-I gene expression following induction of the cellular stress response in HTLV-I-infected lymphocytes. The cellular stress response was elicited by treatment with either Na arsenite or thermal stress and was monitored by demonstrating increased expression of the 72-kDa heat shock protein. Induction of the cellular stress response in HTLV-I-infected lymphocytes resulted in significantly increased HTLV-I-mediated syncytia formation due to enhanced HTLV-I envelope (gp46) expression. Intracellular viral proteins and released p24 capsid protein were increased in stressed infected lymphocytes as compared to nonstressed infected lymphocytes. Furthermore, HTLV-I-LTR reporter gene constructs had increased activity (three- to sixfold) in a transiently transfected, uninfected lymphocyte cell line following induction of the cellular stress response. Quantitation of HTLV-I RNA expression by slot blot analysis of infected lymphocytes suggested variable increases in RNA accumulation. Northern blot analysis demonstrated no qualitative changes in expression of RNA species. These data suggest a relationship between modulation of viral replication and a basic cellular response to stress and have important implications for understanding host cell control mechanisms of HTLV-I expression.     

Renal expression of interleukin-2 receptor mRNA in patients with crescentic glomerulonephritis

A microcolony assay was used in conjunction with fractionated gamma irradiation to determine the number of clonogens in murine intestinal crypts with varying doses of irradiation used in the determination. The experimental design allows direct comparison between two-dose methodologies, employing one and two (or two or four) equal dose fractions, and multiple-dose methodologies involving determination of the crypt survival curves for a number of fractionation regimens using equal doses per fraction. The two-dose methodology yielded estimates of clonogen number of between 3 and 4 at low delivered dose (single and double fractions each of 6.5-7.5 Gy), rising to around 40 at high biological doses (two and four fractions each of 5.75 or 6.5 Gy). The multifraction methodology yielded estimates of clonogen number which increased from 13 after a single fraction to values of 26 and 22 after three and four fractions. However, the latter values were reduced to 11 and 9, and showed little evidence of any dependence on fraction number, when data pertaining to high biologically effective doses were excluded. Hence it is concluded that the high values for clonogen number typically deduced from such multiple-dose protocols, compared with the generally lower (but dose-dependent) values obtained from two-dose protocols, may be explained at least partially by the higher biological doses generally employed in the multiple-dose protocols.