Deleterious Properties Research Articles

The role of symptom induction in the treatment of panic and anxiety. Identifiable domains, conditional properties, and treatment targets.

Although the importance of affectively charged material in the treatment of panic and anxiety has been emphasized and implicitly viewed as essential for effective therapeutic change, a general framework for organizing, understanding, implementing, and evaluating symptom induction techniques has yet to be offered. This article offers a framework for organizing symptoms induction techniques, categorizing treatment targets, and, accordingly, assessing therapeutic change in the treatment of panic and anxiety. Symptom induction techniques are examined in three exposure domains: physiological, cognitive, and situational/circumstantial; treatment targets fall into five categories: (a) poor symptom tolerance and resultant hypersensitivity and hypervigilance, (b) avoidance of internal and external triggers, (c) the emergence of specific catastrophic thoughts and related misinterpretations, (d) diminished adaptive coping skills, and (e) a reduction in general self-efficacy. Additionally, a distinction is proposed between conditional and unconditional properties of symptom induction, with an emphasis on the potential deleterious role conditional properties play during the course of treatment.

Transgenic models of neurodegenerative diseases

Identification of genetic mutations linked to familial neurodegenerative diseases have made it possible to generate useful transgenic animal models. Studies using these transgenic animals indicate that many familial neurodegenerative diseases, such as motor neuron disease, Alzheimer's disease, prion disease and trinucleotide repeat diseases, result from a gain of deleterious properties. The disease-specific pathology in transgenic mice demonstrates the utility of these models in elucidating pathogenic mechanisms of the disease and in developing therapeutic strategies.

Huntington's disease: CAG genetics expands neurobiology

Huntington's disease, with its progressive uncontrolled movements and characteristic selective neuropathology, has represented a baffling enigma to geneticists and neurobiologists alike. Discovery of the HD gene and its defect has demystified the genetic aspects of the disorder, but has not yet explained its pathogenesis. Attempts to explore this issue suggest that the defect acts as a gain of function, conferring a new deleterious property on the huntingtin protein, and that the gene's normal function may be irrelevant to the disease process.

Coronary vasodilator reserve. Comparison of the effects of papaverine and adenosine on coronary flow, ventricular function, and myocardial metabolism.

To evaluate coronary flow reserve during cardiac catheterization, intracoronary adenosine and papaverine have been used in the clinical setting. Although papaverine maximizes coronary blood flow, it induces several toxic side effects that reduce its desirability as a coronary dilator. This investigation was designed to compare the subselective intracoronary administration of papaverine with that of adenosine in an animal model. In dogs (n = 34), we studied the effects of each agent on hemodynamics, regional myocardial blood flow, contractility (sonomicrometric and echocardiographic), metabolism (coronary arterial and venous lactate and tissue high-energy phosphates), and electrocardiographic (ST and QT intervals) parameters. Barbiturate and morphine anesthesia/analgesia was induced, and a left thoracotomy was performed. An arterial shunt was created from the left carotid artery to the left anterior descending coronary artery. Two separate groups were studied: group 1 (n = 16) for regional myocardial blood flow and mechanical function and group 2 (n = 18) for biochemical measurements. Adenosine (67 +/- 2 micrograms/min) or papaverine (6 +/- 1 mg/min) was infused into the coronary shunt at a rate of 0.5 + 0.1 ml/min for a maximum duration of 3.5 minutes. Regional myocardial blood flows were determined at control (predrug) and maximal coronary flow using radiolabeled microspheres. All hemodynamic, wall motion, biochemical, and electrocardiographic parameters were also measured at these times. Both drugs produced comparable increases in total and regional coronary blood flows (adenosine, 1.21 +/- 0.15 to 4.83 +/- 0.36 ml/min/g; papaverine, 1.21 +/- 0.05 to 4.89 +/- 0.28 ml/min/g) upon infusion into the left anterior descending coronary artery. Papaverine produced significant (p less than 0.05) changes in subendocardial ST segment electrocardiogram (-2.5 mm), QT prolongation (8 +/- 2%), myocardial creatine phosphate (47% decrease), and coronary sinus serum lactate (277% increase) compared with control. In addition, intracoronary papaverine induced an abnormal contractile pattern. No significant changes in any of these parameters (i.e., ST segment, QT prolongation, myocardial creatine phosphate level, or lactate level) were observed with intracoronary adenosine infusions. We conclude that intracoronary adenosine is comparable to papaverine for maximizing coronary blood flow without the deleterious properties observed with intracoronary papaverine.

Carbide composition changes in a low alloy steel

Durehete 1055 is a 1%Cr1%Mo¾%V low alloy steel used as bolting material at 565°C. It also contains 0.08%Ti and 0.005%B to improve the creep behaviour, but deleterious properties have been reported, due to the presence of trace elements such as P and Sn. The present work has been an attempt to understand this problem by examining three vacuum melted casts of this steel containing selected additions (wt.%) of 1) 0.08 Ti, 2) 0.08 Ti and 0.02 P; and 3) 0.08 Ti and 0.02 Sn. The material was heat treated for 2h at 980°C, W.Q., and tempered 4h at 680°C, giving a prior austenite grain size of 8 μm. Specimens were then crept for various times at 565°C. After test, metallographic samples were prepared from both the gauge lengths (stressed) and heads (unstressed) to enable the production of carbon extraction replicas. These replicas were examined in a Philips 400T electron microscope, and carbides analysed using EDS.

Geology of Johannesburg, Republic of South Africa

Payable gold was discovered in 1886 on the farm Langlaagte some 5 km to the west of what is now the Central Business District (CBD) of Johannesburg. A village grew around the diggings and in 1897 the Johannesburg Municipality was constituted. Johannesburg is now by far the largest city in South Africa. It is the centre of the world9s largest gold-mining industry and has become the biggest engineering and manufacturing centre on the African continent. The rocks of four major stratigraphic sequences are represented in Johannesburg. The oldest rocks in the area comprise some of the most primitive assemblages on earth. These are isolated remnants of greenstones which survived assimilation by the Archaean Basement granitic rocks. The residual and transported soils derived from greenstones are often highly expansive. The Archaean Basement granitic rocks occur in the northern suburbs of Johannesburg and on weathering have produced soils with a collapsible fabric. Sediments of the Witwatersrand Supergroup partly cover the granitic rocks and associated greenstones. The major portion of the Central Business District and adjacent areas are occupied by this east-west-striking and southward-dipping succession of shales, quartzites and conglomerates. A characteristic geotechnical problem associated with the Witwatersrand rocks is the extreme variability over relatively short distances in a north-south direction. There are two occurrences of rocks of the Ventersdorp Supergroup in the Johannesburg area. The northern-most one is in the form of a graben, down-faulted between Witwatersrand rocks to the north and south of it. Residual soils within the graben are regarded as some of the most highly compressible soils on the Highveld. The second occurrence of the Ventersdorp Supergroup is on the southern boundary where transported and residual soils derived from the andesites are highly expansive. Mafic dykes, generally deeply weathered, occur in abundance in all rock types in the city. A variety of transported soils of the Quaternary Period occur as an ubiquitous blanket covering the underlying residual soils or bedrock. Aggregates from crushed waste rock from the mine dumps account for 74 percent of the total aggregate consumption in the Johannesburg area. The quartzite, however, contains very small amounts of pyrite which, under certain conditions, gives rise to an aggregate with potentially deleterious chemical properties. Granite and andesite are the remaining aggregate sources. Mining residue deposits in the form of slimes dams and sand dumps are common in many residential and industrial townships of Johannesburg. They pose severe and complex environmental problems such as water and dust pollution as well as long term erosion and slope stability problems. Restrictions have been imposed by the Government Mining Engineer on the development of sites which have been undermined to depths less than 244 m. This has affected a strip of ground 500 m wide, very close to the CBD. There is, however, a move by property owners, developers and consultants towards a relaxation of this constraint on development.

Oxidant damage mediates variant red cell resistance to malaria

IT is thought that the deleterious properties of thalassaemia (thal) and glucose-6-phosphate dehydrogenase deficiency (G6PD−) are balanced in the population by a conferred protection against malaria, and that some characteristic of the variant red cell acts directly to inhibit the invasion or intracellular development of the malaria parasite. Indeed, such is the case for sickle cell disorders1,2. Recently, Pasvol et al.3, having shown that fetal haemoglobin (HbF) (in both fetal and adult cells) inhibits malaria parasite development, have suggested that the slight persistance of HbF in children with thal trait is responsible for the selective advantage of the thal gene. They have reported no difference in parasite development in the red cells of adult carriers of thal. Evidence is presented here that both α- and β-thal trait red cells from adults are refractory to parasite development because of oxidant sensitivity, and, furthermore, that fetal red cells and G6PD− cells are refractory for the same reason.

The Biological Effects and Mode of Action of L-Canavanine, a Structural Analogue of L-Arginine

Many of the 200 or so non-protein amino acids synthesized by higher plants are related structurally to the constituents of common proteins. L-Canavanine, the guanidinooxy structural analogue of L-arginine, is representative of this group. It has provided valuable insight into the biological effects and the mode of action of non-protein amino acids which acts as analogues of the protein amino acids. The arginyl-tRNA synthetases of numerous canavanine-free species charge canavanine, and canavanine is subsequently incorporated into the nascent polypeptide chain. Production of canavanine-containing proteins ultimately can disrupt critical reactions of RNA and DNA metabolism as well as protein synthesis. Canavanine also affects regulatory and catalytic reactions of arginine metabolism, arginine uptake, formation of structural components, and other cellular precesses. In these ways, canavanine alters essential biochemical reactions and becomes a potent antimetabolite of arginine in a wide spectrum of species. These deleterious properties of canavanine render it a highly toxic secondary plant constituent that probably functions as an allelochemic agent that deters the feeding activity of phytophagous insects and other herbivores.

EXCHANGE REACTIONS IN METABOLISM

Abstract Recent studies from this laboratory [l, 2] on the reaction mechanism of the pentose phosphate pathway in rabbit and rat liver cells have accentuated the role of enzyme-catalyzed exchange reactions as a means by which tracer carbon is relocated in the absence of a net metabolic flux. While this is an intrinsic property of the group transferring enzymes of the pathway and is seen as a deleterious property of 14C for the mapping and quantitation of metabolic pathways, it has re-emphasized the possible usefulness of isotope exchange reactions in understanding the mechanism of action of nature's catalyst.

ANTIGENICITY OF VARIOUS GLUTEN FRACTIONS.

The antigenic properties of various wheat-gluten fractions were investigated and compared with their known harmful and nonharmful properties when ingested by patients with nontropical sprue. Gluten fractions were suspended in complete Freund's adjuvant and injected into the foot pads of rabbits on 5 consecutive days. A final intraperitoneal injection was also given. Investigation of antibodies in their serum 3 and 6 weeks thereafter by means of double gel diffusion showed no correlation between the reported harmful and the antigenic properties of some of the fractions. This indicates that the deleterious properties of gluten and its fractions can not be attributed to their antigenicity.

SYSTEMATIC INSTRUCTION IN COOKERY AS A BRANCH OF COMMON SCHOOL EDUCATION.

The number of inhabitants who may be supported in any country, upon its internal produce, depends almost as much upon the state of the art of cookery as upon that of agriculture. (Count Rumford, Complete Works, vol. iv, p. 407.) It is needless to call the attention of the members of this Section to the great importance of a sufficient supply of digestible and assimilable food for the maintenance of health. Physiologists have determined, both by experiment and empirically, that the different classes of food-stuffs—proteids, fats, and carbohydrates, with salts and water, must be consumed in definite proportions, if the individual's health shall be preserved. It is equally unnecessary to argue in favor of having all the various articles of food used by man of good quality and free from deleterious properties, because the sanitary conscience of every individual, no less than the physical reactions of the system, demand that