An expert aid to fault diagnosis and trouble-shooting in satellitecommunications

Presents the Satellite Communications Network Expert (SaNE), a knowledge-based aid designed to provide engineering support for fault diagnosis. The SaNE is composed of two elements: a satcom network model, which simulates the structure and functionality of a system based loosely upon a large military satcom network, and a diagnostic component, which uses knowledge- and model-based reasoning techniques to analyse system anomalies and diagnose possible causes for the alarms such networks generate. The development cycle is described, emphasising lessons learnt during development and testing and the advantages and disadvantages of the techniques applied. The goal of the SaNE project is primarily commercial acceptance rather than innovation. The authors illustrate how novel concepts can be implemented in a practical system without compromising this goal     

Metastatic pulmonary artery sarcoma. Report of a case with diagnosis by fine needle aspiration

Spontaneously hypertensive rats (SHR) of 3 to 12 months of age learned and retrieved less information than normotensive Wistar-Kyoto rats (WKY), although no difference was found with animals from 18 and 24 months of age. The combined influence of hypertension and aging had an additive detrimental effect on cognitive functions. Notwithstanding these deficiencies in learning and memory, SHR have seldom been used as a model in the screening of drugs with therapeutic potential for treatment of disorders of cognitive processes. Moreover, the calcium channel blocker nimodipine has beneficial effects on learning in both aged and hypertensive animals and humans. However, no attempt has been made to investigate whether nimodipine can reverse the additive deleterious effects of aging and hypertension in the same subject. We recently reported that deteriorated animals (middle-aged and/or hypertensive) chronically treated with nimodipine (via osmotic minipumps) exhibit higher learning scores. This information indicates that nimodipine can reverse the impairing effects of either aging or hypertension on learning; the presence of the two conditions, however, produces a severe impairment that can be partially reversed by this drug. Therefore, we propose that mature and middle-aged SHR represent a model for the screening of potentially useful drugs in the treatment of learning disorders, probably associated with hypertension and/or aging. Nevertheless, it must be remembered that the SHR is a genetic model and the appearance of neural disturbances could be a parallel genetic phenomenon and not necessarily or exclusively related to hypertension per se.     

Renal proliferative and phenotypic changes in rats with two-kidney, one-clip Goldblatt hypertension

Previous research in this laboratory has shown that preweaning and postweaning juvenile meadow voles, Microtus pennsylvanicus, can acquire a spatial task, the Morris water-maze task. The present study examined the influence of age of juvenile acquisition ("before weaning" (BW; Day 10 and 15 after birth) and "after weaning" (AW; Day 20 and 25 after birth)) of a spatial task on subsequent re-acquisition of the same hidden-platform spatial water-maze task. This study also compared sex differences and litter sex-ratio effects on reacquisition performance. Fifteen litters of adults were re-tested in the same water maze 6 weeks after being initially tested as juveniles. All analyses were conducted using a covariate that removed the group differences in the original task performance. Adult voles from female-biased litters, that had previously learned the task at an older juvenile age (AW), reacquired the same task faster than adults that had previously learned the task at a younger juvenile age (BW). In the adult BW group there was also a significant litter sex-ratio effect such that voles born into a female-biased litter re-acquired the task more slowly than did voles born into a male-biased litter. There were no significant sex or litter sex-ratio effects on spatial learning in the AW group. These results show that adult meadow voles can require a spatial task more quickly if they initially learned the task at an older juvenile age, suggestive of a period of infantile amnesia. In addition, these results indicate that the litter sex-ratio can affect adult spatial performance, suggesting that the relative amount of androgens in utero may influence the development of sexually-dimorphic spatial ability in adulthood.     

Psychosomatic disease and the problem of causation

Despite its impressive rate of growth in the past decades, an increasing amount if dissatisfaction with the area of psychosomatic medicine is reflected in recent literature. The discipline's failures relate to concepts of pathogenesis and therapeutic application of research findings. These failures are explained as a necessary consequence of the philosophical tenet of mind-body dualism which underlies medical theory. It is urged that advocates of psychosomatic medicine give the concept of "holism" meaning at the most fundamental level by establishing a rational basis for theory, or else forsake this line of research for others which yield causal relationships conductive to effective therapy.     

Detection and estimation of collagen

Collagen exists in at least five genetically distinct forms and the relative abundance of these is determined by the type and age of the tissue. Methods are presented for the detection and estimation of these collagens based on appropriate chemical, physical, histochemical and immunological techniques. The specific difficulties in providing accurate quantitative data for collagen in meat and meat products'are discussed.     

Effects of simulated digestion in vitro on cell wall polysaccharides from kiwifruit (Actinidia spp.)

Cell wall polysaccharides are resistant to digestion and absorption in the human small intestine and are considered to be delivered to the colon in a chemically unaltered state. In this paper, pulp from green and gold kiwifruit was subjected to in vitro upper-intestinal tract digestion and the chemical and physical changes to cell wall polysaccharides (dietary fibre) were investigated. Yields of insoluble fibre decreased slightly with simulated digestion while soluble fibre yields increased. Constituent sugar and glycosyl linkage analysis of the soluble and insoluble fibre fractions revealed that the chemical composition and structure of the non-starch polysaccharides remained largely unchanged. However, the degree of methylesterification of galacturonic acid residues present in the pectin-rich soluble fibre fractions of both fruit decreased with treatment; size-exclusion chromatography detected changes in the molecular weight profiles of these fractions. These changes may affect the physicochemical properties and fermentability of kiwifruit dietary fibre in the large intestine.     

Prostaglandin F and progesterone secretion by porcine endometrium and corpus luteum in vitro

Slices of porcine endometrium and corpus luteum tissue obtained from mature sows throughout the luteal phase of the oestrous cycle were incubated in culture medium which was analysed at regular intervals over a period of 8 hours for prostaglandin F and progesterone. Prostaglandin F secretion was greatest by endometrium obtained during the mid III to late I luteal stage of the cycle and the increased levels secreted by this tissue were paralleled by high levels of secretion from corpus luteum tissue. The addition of indomethacin (10 mug/ml) to the culture medium completely abolished prostaglandin F secretion by both endometrium and luteal tissue indicating that the high levels of the prostaglandin were due to synthesis. Progesterone secretion by the corpus luteum was maximal from early luteal tissue and had declined to considerably lower levels by late stage tissue when prostaglandin secretion was greatest. The possible physiological significance of luteal prostaglandin F secretion is discussed.     

Awareness and dreams during general anaesthesia for Caesarian section a study of incidence

One hundred Nigerian patients presenting for emergency caesarian section were interviewed within the first 24 hours post-operatively. The purpose was to determine the incidence of awareness and dreams. The standard anaesthetic technique consisted of atropine 0.6 mg and thiopentone 250 mg given intravenously at the time of induction, suxamethonium bromide 40 mg intravenously to facilitate tracheal intubation and nitrous oxide/oxygen/pancuronium for maintenance. The incidence of awareness was 4% while the incidence of dreaming was 17%. Most (94%) of the patients said they dreamed only occasionally at home and of these, 15% claimed they dreamed more frequently when pregnant than when not pregnant.     

The effect of paraben preservatives on albumin binding of bilirubin

The effect of sodium taurocholate in stepwise increasing infusion rates, 0.3 to 9.6 mumoles per min per kg, on the biliary excretion rate of iodipamide was investigated in 6 dogs (10 experiments) with complete bile diversion under general anesthesia. Iodipamide was administered intravenously with an initial priming dose of 33 mumoles per kg followed by a constant infusion of 1.3 mumoles per min per kg. Although the bile flow continuously increased with an increasing taurocholate dose, the iodipamide excretion rate reached a plateau with a 0.6 mumoles per min per kg of taurcholate infusion, which was 20% higher than with the lowest taurocholate dose. With a taurocholate dose over 2.4 mumoles per min per kg, a significant decrease in the iodipamide rate was found, amounting to 22% of its maximum value with the largest taurocholate dose. The bile iodipamide concentration was already at its maximum with the lowest taurocholate dose, and it decreased with an increasing taurocholate dose. Since the bile iodipamide concentration is probably the most important determinant in clinical cholangiography, low bile salt plasma levels should result in the best radiographic visualization of the biliary tree.