ATP radionuclide ventriculography; its usefulness for the evaluation of ischemic heart disease

The susceptibility of 45 strains of Neisseria gonorrhoea was studied measuring minimal inhibitory concentrations of five antimicrobials. Results show that 66.7% of strains are resistant to tetracycline and 11.2% to penicillin. All strains were susceptible to ciprofloxacin, ceftriaxone and cefotaxime. This results should prompt to perform surveillance in different areas of Santiago and to establish new therapeutic norms for the treatment of gonococcal infections.     

Functional expression of Fas antigen (CD95) on hematopoietic progenitor cells

We investigated the expression of an apoptosis-associated antigen (Fas) (CD95) on hematopoietic progenitor cells in the presence or absence of interferon-gamma (IFN-gamma) and/or tumor necrosis factor-alpha (TNF-alpha). CD34+ cells freshly isolated from bone marrow did not express Fas. However, IFN-gamma and/or TNF-alpha induced the expression of both the mRNA of Fas and Fas itself in a dose-dependent fashion on the surface of CD34+ cells after 48 hours of serum-free culture. IFN-gamma and TNF-alpha had a synergistic effect on the induction of Fas, when both cytokines were added to the culture. The TNF-alpha-induced Fas expression is mediated by p55 TNF-alpha receptor. CD34+ cells cultured in medium alone or with stem cell factor (SCF) showed some slight expression of Fas. When anti-Fas antibody (IgM) was added to CD34+ cells after the induction of Fas expression, CD34+ cells underwent apoptosis, as shown by a decrease in the number of viable cells, morphologic changes, the induction of DNA fragmentation, and a decrease in the number of colony-forming cells (CFC) including colony-forming unit granulocytes/macrophages (CFU-GM) and burst-forming unit erythroids (BFU-E). These observations indicate that IFN-gamma and/or TNF-alpha, well known as negative hematopoietic regulators, induce functional Fas on hematopoietic progenitor cells. The suppression of hematopoiesis by negative hematopoietic regulators may be mediated in part by Fas induction.     

Interaction between substitutional and interstitial solute atoms in α iron studied by isothermal mechanical spectroscopy

The interaction of interstitial nitrogen with substitutional alloying elements has been studied by measuring the Snoek relaxation in very dilute Fe–X–N ternary alloys (X: V, Cr, Mn, Mo). Isothermal measurements by the sub-resonance forced-vibration technique have revealed characteristic influence of substitutional solutes on the Snoek relaxation, which can be understood as trapping of N atoms at neighbouring sites of X atoms. The interaction energy has been evaluated by comparing the relaxation profiles observed experimentally with those calculated theoretically. The values thus obtained are of the order of 0.1 eV, with the magnitude being larger for elements of smaller group numbers, and are similar to those in the γ and liquid phases.     

Reaction Mechanisms of Silicon Carbide Fiber Synthesis by Heat Treatment of Polycarbosilane Fibers Cured by Radiation: I, Evolved Gas Analysis.

SiC fibers were synthesized from polycarbosilane (PCS) fibers by heat treatment after electron beam irradiation curing. The pyrolysis reaction mechanisms from the organic PCS to ceramic SiC were investigated by the analysis of gases evolved during heat treatment. There were two steps in the major reaction: the first step was at 800–1200 K where H₂ and CH₄ evolved by scission of Si-CH₃ and Si-H and by rearrangement reactions, and the second step was at 1000–1700 K where H₂ evolved by reactions related to C atoms in the PCS main chain. H₂ evolution in the first step was reduced with increasing oxygen content in the cured PCS fibers.     

A model for simultaneous measurement of gas and solid holdups in a bubble column using ultrasonic method

The ultrasonic method developed to measure the dispersed phase holdups in dispersion systems is based on the fact that the velocity of ultrasound in the dispersion is different from that in the liquid. The relationships between velocity differences in the term of transmission time differences of ultrasound and gas holdup in a gas-liquid system and solid holdup in a liquid-solid system were derived. The holdups became linearly dependent on the time differences, which is in agreement with the experimental data. Based on those relations, a model for simultaneous measurement of gas and solid holdups in three-phase systems is proposed. The model permits measurement of the dispersed phase holdups by measuring the transmission time of ultrasound transmitted through the dispersions in two frequencies. It allows investigation of local holdups distributions in a bubble column and in a suspended bubble column.     

Hepatic infarction following percutaneous ethanol injection therapy for hepatocellular carcinoma

We report on two patients who developed hepatic infarction after undergoing percutaneous ethanol injection therapy (PEIT) for hepatocellular carcinoma (HCC). In both cases, liver function parameters deteriorated immediately after the ethanol injection, and enhanced computed tomography images showed a wedge-shaped avascular low-density area due to hepatic infarction. In one patient, PEIT was performed for a nodule treated with transcatheter arterial infusion (TAI) using a suspension of styrene maleic acid neocarzinostatin (SMANCS) 4 weeks before. In the other patient, TAI with SMANCS had been carried out 14 months previously for a different nodule in the same segment where the nodule treated with PEIT was located. When PEIT is used for patients with HCC who have previously undergone TAI, especially with SMANCS, PEIT may induce hepatic infarction.     

A clinical study of hypergraphia in epilepsy

Fifteen patients with epilepsy and hypergraphia were compared with 32 patients with epilepsy but without hypergraphia. The number of previous psychiatric episodes, the number of Washington Psychosocial Seizure Inventory (WPSI) items indicating emotional maladjustment, and the number of CT scan abnormalities were significantly greater in the hypergraphic patients than in the non-hypergraphic patients. Cognitive performance, EEG laterality and the scores of WPSI items related to the psychological stress of seizures did not differ significantly between the two groups. Hypergraphia reflects changes in emotional responsiveness secondary to organic temporal lobe lesions.     

Viscoelastic properties of (cellulose oligo-oxymethylene ether) acylates with bulky side chain

A series of (cellulose oligo-oxymethylene ether) acylates (COAs) are characterized by the presence of the micro-Brownian motion of the side chain (β process) which appears separately from that of the main chain (α process). Both the alpha; and β processes are largely affected by the kind of acyl groups introduced in the side chain. To clarify the effect of the acyl group on these processes, we investigated the dynamic mechanical properties of newly prepared COAs with acyl side chain, bulky in chemical structure (iso-butyrate, privalate, and benzoate) in relation to those for COAs with linear acyl side chain (acetate, butyrate, and valerate). By substituting bulky acyl isomer for linear acyl group in COAs, we observed that the temperature region of both the α and β processes moved to higher temperature. Furthermore, with an increase in molecular size of bulky acyl group, the β region shifts were much larger than the α region, indicating that the mobility of the side chain became comparable to that of the main chain. Finally, when such a large bulky group, for example, benzoate was introduced, the micro-Brownian motion of the side chain prior to that of the main chain ceased. The apparent activation energy for a third process (γ) due to the motion of the oligo-oxymethylene parts in the side chain was estimated to be 10.3 kcal/mol.