Highly-efficient technique for automatic segmentation of X-ray bone images based on fuzzy logic and an edge detection technique

Multidimensional Systems and Signal Processing - Development of medical image segmentation techniques has become one of the most important challenges in many applications that employ...     

Luteinizing hormone releasing hormone (LHRH) neurons maintained in nasal explants decrease LHRH messenger ribonucleic acid levels after activation of GABA(A) receptors

Inhibition of the LHRH system appears to play an important role in preventing precocious activation of the hypothalamic-pituitary-gonadal axis. Evidence points to gamma-aminobutyric acid (GABA) as the major negative regulator of postnatal LHRH neuronal activity. Changes in LHRH messenger RNA (mRNA) levels after alterations of GABAergic activity have been reported in vivo. However, the extent to which GABA acts directly on LHRH neurons to effect LHRH mRNA levels has been difficult to ascertain. The present work evaluates the effect of GABAergic activity, via GABA(A) receptors, on LHRH neuropeptide gene expression in LHRH neurons maintained in olfactory explants generated from E11.5 mouse embryos. These explants maintain large numbers of primary LHRH neurons that migrate from bilateral olfactory pits in a directed manner. Using in situ hybridization histochemistry and single cell analysis, we report dramatic alterations in LHRH mRNA levels. Inhibition of spontaneous synaptic activity by GABA(A) antagonists, bicuculline (10(-5) M) or picrotoxin (10(-4) M), or of electrical activity by tetrodotoxin (TTX, 10(-6) M) significantly increased LHRH mRNA levels. In contrast, LHRH mRNA levels decreased in explants cultured with the GABA(A) receptor agonist, muscimol (10(-4) M), or KCl (50 mM). The observed responses suggest that LHRH neurons possess functional pathways linking GABA(A) receptors to repression of neuropeptide gene expression and indicate that gene expression in embryonic LHRH neurons, outside the CNS, is highly responsive to alterations in neuronal activity.     

Improvement of some pharmaceutical properties of drugs by cyclodextrin complexation. 4. Chlorpromazine hydrochloride

This study is a retrospective review of admissions, discharge records and blood culture results of neonates admitted to the Neonatal Intensive Care Unit of Korle Bu Teaching Hospital in Accra, from the first of January 1991 to the 31st of December 1992. During this two year period there were 443 positive blood cultures. Ninety percent of the blood cultures were from babies born in Korle Bu Teaching Hospital, thus making the incidence of neonatal bacteraemia 22.2 per 1000 live births. The overall mortality rate was 37.2%. Gram negative bacteria accounted for 70.9% and Gram positive bacteria for 29.1% of all neonatal bacteraemia. The most common isolates were Enterobacter species 29.6%; Streptococcus faecalis 14.4%; Staphylococcus aureus 10.8%; Acinetobacter species 9.5%; Klebsiella species 9% and Escherichia coli 8.8%. It is concluded that the incidence of neonatal bacterial sepsis is high in our hospital and is associated with a very high mortality rate. There is thus an urgent need to institute appropriate preventive and therapeutic measures.     

Subpallidal outputs to the nucleus accumbens and the ventral tegmental area: anatomical and electrophysiological studies

The goal of this study was to investigate the functional organization of the subpallidal-->accumbens direct and indirect feedback loops by both anatomical and electrophysiological methods. The results of the dextran-conjugated rhodamine injections into the subpallidal area has shown three distinct projections: (1) a substantial pathway from the subpallidal area to the ventral tegmental area, (2) a more diffuse rostral projection from the subpallidal area to the core area of the nucleus accumbens, and (3) a sparse pathway projecting rostrodorsally from the subpallidal area toward the thalamic regions. Electrical or chemical stimulation of the subpallidal region, which was studied by the axonal tracer, evoked inhibitory responses in the majority (60 and 80%, respectively) of the accumbens and ventral tegmental area neurons in a standard extracellular recording study. Less than 1/3 of the accumbens or ventral tegmental area cells showed an increase in the mean firing rate. The majority (77.5%) of all responded neurons had a latency of less than 10 ms. Furthermore, injection of glutamate into the subpallidal area not only altered the firing pattern of the accumbens neurons, but also attenuated their excitatory responses elicited by the electrical stimulation of the ventral subiculum. Our results indicate that the subpallidal area plays a predominantly inhibitory role in the ventral tegmental area-accumbens-subpallidal circuitry, presumably by its GABAergic projections, and may also modulate subicular input into the nucleus accumbens.     

Specific substitutions at amino acid 256 of the sarcoplasmic/endoplasmic reticulum Ca2+ transport ATPase mediate resistance to thapsigargin in thapsigargin-resistant hamster cells

High levels of resistance to thapsigargin (TG), a specific inhibitor of intracellular Ca2+ transport ATPases (SERCAs), can be developed in culture by stepwise exposure of mammalian cells to increasing concentrations of TG. We have identified, in two independently selected TG-resistant hamster cell lines of different lineages, mutant forms of SERCA. In the TG-resistant Chinese hamster lung fibroblast cell line DC-3F/TG, a T --> C change at nucleotide 766 introduces a Phe256 --> Leu alteration within the first cytosolic loop of the SERCA. In contrast, in the TG-resistant Syrian hamster smooth muscle cell line DDT/TG 4 microM, a T --> C change at nucleotide 767 introduces a Phe256 --> Ser mutation at that position. When these specific mutations are introduced into a wild-type full-length avian SERCA1 cDNA, transfection experiments reveal that Ca2+ transport function and ATP hydrolytic activity are not altered by such mutations. However, a 4-5-fold resistance to TG inhibition of Ca2+ transport function occurs upon the introduction of either the Phe256 --> Leu or the Phe256 --> Ser mutation into wild-type SERCA1. These specific mutations also render the hydrolytic activity of the ATPase resistant to inhibition by TG. Our results not only implicate amino acid 256 in TG-SERCA interactions, but also demonstrate that specific mutations within SERCA can mediate resistance to TG.     

Should diastasis recti be corrected?

From theoretical considerations animals with a higher protein-fat ratio in the body should have a higher maintenance energy requirement (MEm). The literature on this problem shows a non-uniform picture with deviating results. From the results of a series of experiments it is possible to compare the heat production (HP) of male and female animals of the Vietnamese Sway-back breed pigs which vary quite widely in their body composition. The protein-fat ratio was 1.2 for the male and 0.2 for the female animals. In the experiments 4 male and 4 female animals in the live weight range of 20-33 kg and 33-42 kg, respectively, were involved. The HP measurements were carried out in climatized respiration chambers on two levels of energy intake at ambient temperatures of 6 degrees C, 12 degrees C, 18 degrees C, 24 degrees C, 30 degrees C, and 35 degrees C. The dependence of HP on the ambient temperature has been described by a cubic regression function. Thermoneutral temperatures are lower in the female animals caused by the better insulation effect of the backfat. The difference in HP which was expected by the large difference in body composition, was not found. The absolute protein mass determined the correlation to HP. Certainly the difference increased after lowering the ambient temperature. The influence of different factors on HP is discussed.     

Kinetics of catalytic esterification of terephthalic acid with methanol vapour

This paper describes the investigations carried out on the kinetics of the solid-gas reaction between terephthalic acid and methyl alcohol in presence of phosphoric acid as the catalyst. As phosphoric acid itself reacts with the alcohol forming methyl phosphates, the kinetic data obtained have been analysed taking this reaction into account. The rate of formation of monomethyl phosphate has been found to be proportional to the square of the mole fraction of the acid present at any instant. The activation energy involved in this reaction is 11.3 kcal/g mole. The data obtained on terephthalic acid esterification show that; (i) the conversion sharply increases with an increase in the catalyst concentration between 30–35 per cent (w/w), (ii) the ‘shrinking particle’ model, proposed by Levenspiel for solid-gas reactions, can be conveniently adapted to represent the reaction, and (iii) the temperature dependency of the reaction follows the Arrhenius law, with activation energy being 11.5 kcal/g mole.