Sensitivities of Human Monocytes and Epithelial Cells to Pneumolysin Are Different

The Streptococcus pneumoniae pore-forming toxin, pneumolysin, is an important virulence factor in pneumococcal pneumonia. The effect of pneumolysin on human lung epithelial and monocyte cell viability was compared. Pneumolysin caused a dose-dependent loss of viability of human lung epithelial (A549 and L132) and monocyte (U937 and THP-1) cell lines. Analysis of the dose-response curves revealed similar log 50% inhibitory concentration (pIC(50)) values for A549, L132, and THP-1 of 0.12+/- 0.1, 0.02+/- 0.04, and 0.12+/- 0.13 hemolytic units (HU), respectively, but U937 cells showed a significantly greater pIC(50) of 0.42+/- 0.12 HU. Differentiation of A549 and L132 with phorbol ester or THP-1 with gamma interferon had no effect on their sensitivity to pneumolysin. However, a significant decrease in the potency of pneumolysin against U937 cells followed gamma interferon treatment. The Hill slopes of the inhibition curves were greater than unity, indicating that pneumolysin may act with positive cooperativity. Analysis of pneumolysin-treated THP-1 cells by electron microscopy revealed membrane lesions of between 100 and 200 nm in diameter.     

Establishment and characterization of a continuous human chondrosarcoma cell line,ch-2879: comparative histologic and genetic studies with its tumor of origin

Chondrosarcomas are malignant cartilage-forming tumors that represent the second most common malignant solid tumor of bone. These biologically poorly understood neoplasms vary considerably in clinical presentation and biologic behavior. Chemotherapy and radiation therapy are generally ineffective. Here we describe the establishment and characterization of a new human chondrosarcoma cell line named ch-2879, and we compare the cell line with its tumor of origin. The cell line was established from a recurrent grade 3 chondrosarcoma of the chest wall and characterized by growth kinetics and morphologic studies. Immunocytochemistry and RT-PCR were performed to examine the expression of cartilage-specific phenotypes. Genetic characterization was performed using cytogenetics, fluorescence in situ hybridization, flow cytometry, and molecular techniques for analysis of the genes implicated in cell cycle control, amplification of MDM2, CDK4, and Cyclin D1, and mutations in the p53 gene. ch-2879 cells were subcultured for more than 80 passages. They expressed vimentin, HNK-1, HBA-71, Ki-67, cyclin D1, Fli-1, S-100, p21, p27, and p53 and were negative for cytokeratin, EMA, p14, p16, MDM2, Rb, and c-erb-b2 antigens. Cytogenetically the recurrent tumor showed a hyperhaploid karyotype with clonal numerical and structural abnormalities. The sole structural abnormality was a chromosome derivative of a t(1;21) translocation. The cell line at passage 3 showed two populations: the hyperhaploid and an exactly duplicated, hypotriploid population. After the 18th passage, only the hypotriploid population was present. The cells expressed collagen 2. Molecular comparison of the primary and recurrent tumor evidenced an in vivo molecular change consisting of a deletion of 9p21 genes in the recurrence, probably caused by a selection process. Because of its gene expression profile, including expression of genes implicated in chondrogenesis in uncoated plastic dishes, this cell line may prove useful for cellular and molecular studies as well as studies of chondrosarcoma characterization and treatment.     

Acute and Subacute Toxicity of Aspilia Africana Leaves

This study was designed to evaluate the toxicity of the aqueous extract of Aspilia africana leaves. Oral doses of 500 mg/kg and 1000 mg/kg were administered for 28 days to rats after every 2 days for sub-acute toxicity. For acute toxicity, 5 doses of 2, 4, 8, 12 and 16g/Kg body weight were investigated in mice. The control groups consisted of mice or rats administered with distilled water. The signs of toxicity fluctuated lightly from one mammal to another throughout the experiment. The liver, kidneys and heart weight of rats revealed no significant differences between the test groups and the control. The results indicated that the medium lethal dose (LD₅₀) was found to be greater in females than males with an average of 6.6g/Kg body weight for both sexes. Regardless of the significant differences observed at certain points in some biochemical parameters (ALT, AST, ALP, Creatinine and Glutathione); none showed any linear dose responsiveness. On the other hand, most of the parameters investigated were found to be gender dependent. These results suggested that A Africana can be classified among substances with low toxicity.     

Restriction of visual experience to a single orientation affects the organization of orientation columns in cat visual cortex

Summary and Conclusions In six dark reared, 4-weak-old kittens visual experience was restricted to contours of a single orientation, horizontal or vertical, using cylindrical lenses. Subsequently, the deoxyglucose method was used to determine whether these artificial raising conditions had affected the development of orientation columns in the visual cortex. After application of the deoxyglucose pulse one hemifield was stimulated with vertical, the other with horizontal contours. Thus, from interhemispheric comparison, changes in columnar systems corresponding to experienced and inexperienced orientations could be determined. The following results were obtained: (1) Irrespective of the restrictions in visual experience, orientation columns develop in areas 17, 18, 19 and in the visual areas of the posterior suprasylvian sulcus. (2) Within area 17, spacing between columns encoding the same orientations is remarkably regular (1 mm), is not influenced by selective experience and shows only slight interindividual variation. (3) In non-striate areas the spacing of columns is less regular and the spatial frequency of the periodicity is lower. (4) The modifiability of this columnar pattern by selective experience is small within the granular layer of striate cortex but substantial in non-granular layers: Within layer IV columns whose preference corresponds to the experienced orientation are wider and more active than those encoding the orthogonal orientation but the columnar grid remains basically unaltered. Outside layer IV the columnar system is maintained only for columns encoding the experienced orientations. The deprived columns by contrast frequently fail to extend into non-granular layers and remain confined to the vicinity of layer IV. (5) These modifications in the columnar arrangement are more pronounced in striate cortex than in non-striate visual areas and, within the former, more conspicuous in the central than in the peripheral representation of the visual field. It is concluded that within layer IV the blue print for the system of orientation columns is determined by genetic instructions: first order cells in layer IV develop orientation selectivity irrespective of experience whereby the preference for a particular orientation is predetermined by the position in the columnar grid. Dependent on experience is, however, the expansion of the columnar system from layer IV into non-granular layers. It is argued that all distortions following selective rearing can be accounted for by competitive interactions between intracortical pathways, the mechanisms being identical to those established for competitive processes in the domain of ocular dominance columns. It is proposed that such experience dependent modifiability of connections between first and second order cells is a necessary prerequisite for the development of orientation selectivity in cells with large and complex receptive fields.This work has partially been supported by a grant from the Deutsche Forschungsgemeinschaft, SFB 50, A14Dedicated to Prof. D. Ploog on the occasion of his 60th anniversaryResearch Fellow of the Alexander-von Humboldt-Stiftung     

Renovaskuläre Hypertonie

Zusammenfassung In der vorliegenden Untersuchung wurde das postoperative Blutdruckverhalten bei 35 Patienten mit renovaskulärer Hypertonie untersucht: 17 Patienten mit fibromuskulärer Dysplasie (FMD) und 18 mit arteriosklerotischen Gefäßwandveränderungen (ASS).Patienten mit FMD waren im Mittel jünger (31,8 Jahre), zeigten eine kürzere Hypertonieanamnese (1,8 Jahre) und waren prävalent weiblich (82%), während Patienten mit ASS deutlich älter waren (48,2 Jahre), eine längere Hypertoniedauer (2,6 Jahre) zeigten und bevorzugt männlich (78%) waren.In beiden Gruppen zeigte das intravenöse Pyelogramm einen vergleichbar hohen Anteil positiver Befunde (FMD=64%, ASS=61%).Postoperativ waren in der Gruppe mit FMD 47% (n=8) geheilt, 47% (n=8) gebessert und nur 6% (n=1) der Patienten geringgradig gebessert. Die vergleichbaren Werte für die Gruppe mit ASS betrugen 28, 55 und 17%. Für das Gesamtkollektiv war folglich ein guter Operationserfolg (geheilt und gebessert) in 88,5% der Fälle zu beobachten. Patienten mit ASS und postoperativ nur geringgradiger Besserung (n=3) zeigten eine auffallend lange Hypertonieanamnese (7,0±1,4 Jahre).Bei allen Patienten wurde präoperativ die seitengetrennte Bestimmung der Renin-Aktivität (PRA) im Nierenvenenblut durchgeführt und aus den Werten die PRA-Quotienten (PRA betroffene/nicht betroffene Seite) errechnet. Bei 27 Patienten wurde die Bestimmung 15 und 30 min nach intravenöser Stimulation mit 40 mg Furosemid wiederholt. PRA-Quotienten von 1,5 wurden als signifikant bezeichnet.Bei 31 Patienten mit einseitiger renovaskulärer Hypertonie wurde die Höhe des PRA-Quotienten zum postoperativen Blutdruckverhalten korreliert. Dabei zeigte sich zwischen der Gruppe der postoperativ Geheilten und der der postoperativ Gebesserten kein signifikanter Unterschied im mittleren PRA-Quotienten. Ferner ließen sich für das Gesamtkollektiv der 31 Patienten mit einseitiger renovaskulärer Hypertonie unter Ausgangs- und Stimulationsbedingungen keine signifikanten Korrelationen zwischen Höhe der PRA-Quotienten und postoperativem Blutdruckabfall ermitteln.Unsere Ergebnisse unterstützen nicht die weit verbreitete Ansicht, daß sich die seitengetrennte Bestimmung der PRA im Nierenvenenblut als Parameter für den zu erwartenden Operationserfolg bei Patienten mit einseitiger renovaskulärer Hypertonie eignet. Die Methode kann deshalb nach unserer Ansicht nicht mehr als obligater Bestandteile der präoperativen Diagnostik der renovaskulären Hypertonie empfohlen werden.     

Experimental determination of the kinetics of calcium-binding with chondroitin sulphate and the effects of uric acid on this process

Summary The calcium-binding kinetics of chondroitin sulphate C (CS) have been determined using equilibrium analysis including ⁴⁵Ca. There is a linear relationship between the extent of the Ca binding and the concentration of CS present. 1 mol CS disaccharide unit binds 0.757 mol Ca. Scatchard plots of the data have revealed a single constant of dissociation (K _D =1429). In the presence of urate ions, and dependent on the pH value, the ability of CS to bind Ca may be impaired by as much as 31%. These measurements have supported the theory that urate ions interact with the GAGs in urine.     

Apnoeic oxygenation in paediatric anaesthesia: a narrative review

Apnoeic oxygenation refers to oxygenation in the absence of any patient or ventilator effort to move the lungs. This phenomenon was first described in humans in the mid-20th century but has seen renewed interest in the last decade following the demonstration of apnoeic oxygenation with low-flow, and subsequently high-flow, nasal oxygen. This narrative review summarises our understanding of apnoeic oxygenation in the paediatric population. We examine the evidence supporting oxygenation via tracheal tube, modified laryngoscopes and nasal cannulae. The evidence for prolongation of safe apnoea time at induction of anaesthesia is also appraised. We explore the capacity for carbon dioxide clearance, flow rate selection with high-flow nasal oxygen and complications associated with the technique. It remains uncertain whether apnoeic oxygenation in paediatric patients results in a meaningful clinical benefit compared with standard care for outcomes such as the number of tracheal intubation attempts or the incidence of hypoxaemia. In particular, the role of apnoeic oxygenation in paediatric difficult airway management is unclear as this has not been the targeted focus of any published research to date.