The microsurgical treatment of large and giant aneurysms of the internal carotid artery located parasphenoidally

Internal carotid aneurysms in the ophthalmic area presents a challenge in cerebrovascular neurosurgery. The study was undertaken to provide evidence for the application of intravascular aspiration during direct surgical interventions and to outline their variants used at the N. N. Burdenko Institute of Neurosurgery. The study included 4 (3 females and 1 male) patients with large and giant internal carotid aneurysms of parasphenoidal site who were treated at the Institute. Clipping of the aneurysmal neck was made by employing intravascular blood aspiration from the aneurysm. The technique proved to be effective in proximal monitoring the carotid artery at surgery. It substantially reduced aneurysmal blood flow and wall tension, thus favouring aneurysmal dissection to make clipping.     

Performance and buffering requirements of Internet protocols overATM ABR and UBR services

ATM networks are quickly being adopted as backbones over various parts of the Internet. This article studies the dynamics and performance of the TCP/IP protocol over the ABR and UBR services of ATM networks. Specifically the buffering requirements in the ATM switches as well as the ATM edge devices. It is shown that with a good switch algorithm, ABR pushes congestion to the edges of the ATM network while UBR leaves it inside the ATM portion. As a result, the switch ABR buffer requirement for zero-packet-loss high-throughput TCP transmission is a sublinear function of the number of TCP connections     

Knowledge about asthma among Danish primary school teachers. Results of a questionnaire study

An anonymous questionnaire inquiry performed among 324 school teachers in the Randers area with the purpose of elucidating teachers' knowledge about asthma is presented. To a series of statements about asthma, the teachers should answer yes, no or don't know. A limited knowledge about asthma in children was found. The knowledge about medicamental treatment was particularly limited. Only 57 per cent knew that wheezing after physical exertion is a strong indicator of asthma. Only five per cent had received proper instruction. This latter group had a significantly better knowledge of medical treatment (p < 0.0001-0.05). It is recommended that instruction in children's diseases, especially asthma should be reintroduced in teachers' training colleges.     

The prevalence of allergic rhinitis and nasal symptoms in Nottingham

An overview of the most important older and newer results regarding the relationship between violent and criminal behavior on the one hand and schizophrenic illness on the other hand is presented. Four different methods are available to study this relationship: (i) study of the prevalence of mental illness in criminal/violent populations; (ii) study of criminality/violence rate in samples of psychiatric patients; (iii) study of criminality/violence in community samples comparing mental patients with non-patient community residents; and (iv) study of criminality/violence in birth cohorts prospectively. All these methods have been used; but samples composed of schizophrenic patients exclusively were only exceptionally studied. The results indicate that there is a modest but significant relationship between schizophrenia and violence and crime which persists even after controlling for demographic and socio-economic variables. The probability of schizophrenic patients to be criminal or violent depends on the acuity of their illness and is increased by their use of psychoactive substances. Generally, however, violent and criminal acts directly attributable to mental illness account only for a very small proportion of such acts in the society.     

Well-differentiated liposarcoma of the hypopharynx

We report a case of subacute bowel obstruction due to a compression of the rectosigmoid junction by a chronically distended bladder, occurring in a 91-year-old male suffering from a long-standing diabetes mellitus and a prostatic adenoma. Radiographic, water-soluble contrast enema and pelvic CT features are reported.     

Structure of nitric oxide synthase oxygenase dimer with pterin and substrate

Crystal structures of the murine cytokine-inducible nitric oxide synthase oxygenase dimer with active-center water molecules, the substrate L-arginine (L-Arg), or product analog thiocitrulline reveal how dimerization, cofactor tetrahydrobiopterin, and L-Arg binding complete the catalytic center for synthesis of the essential biological signal and cytotoxin nitric oxide. Pterin binding refolds the central interface region, recruits new structural elements, creates a 30 angstrom deep active-center channel, and causes a 35 degrees helical tilt to expose a heme edge and the adjacent residue tryptophan-366 for likely reductase domain interactions and caveolin inhibition. Heme propionate interactions with pterin and L-Arg suggest that pterin has electronic influences on heme-bound oxygen. L-Arginine binds to glutamic acid-371 and stacks with heme in an otherwise hydrophobic pocket to aid activation of heme-bound oxygen by direct proton donation and thereby differentiate the two chemical steps of nitric oxide synthesis.     

Monocyte procoagulant activity induced by adherence to an artificial surface is reduced by end-point immobilized heparin-coating of the surface

Heparin-coating improves the biocompatibility of blood contacting artificial surfaces. This led us to investigate the impact of heparin-coating (Carmeda AB, Stockholm) of polymetylmetacrylate on the expression of monocyte tissue factor procoagulant activity (TF-PCA) by surface adhesion. Also, the anticoagulant effect of heparin-coating in the presence or absence of adherent procoagulant monocytes was assessed. This is of particular interest, since activation of extrinsic coagulation by adherent monocyte TF-PCA may play a significant role in thrombin generation during extracorporeal circulation. Monocytes exposed to heparin-coated or non-coated polymetylmetacrylate expressed TF-PCA. The heparin coat did not affect the rate of monocyte adhesion. However, heparin-coating reduced the induction of TF-PCA of non-adherent and adherent monocytes by 17 and 33% (p <0.001 and p <0.0003), respectively. Heparin-coating in the absence of monocytes, totally inhibited the clotting of recalcified plasma (p <0.003). In contrast, in the presence of adherent monocytes expressing TF-PCA, surface-bound heparin did not inhibit clotting. However, inclusion of heparin in a plasma concentration of 8.9 IU/ml totally inhibited the activation of coagulation. It is apparent that heparin-coating of an artificial surface is an efficient means to inhibit coagulation of recalcified plasma, but much less so when procoagulant monocytes are adherent to the coated surface. The present findings are of clinical relevance, since monocytes will adhere to blood contacting surfaces of extracorporeal circuits or to implanted vascular prostheses and subsequently express TF-PCA, and this may promote thromboembolism.     

Granulocyte colony-stimulating factor worsens the outcome of experimental Klebsiella pneumoniae pneumonia through direct interaction with the bacteria

Besides its well-established effects on granulocytopoiesis, granulocyte colony-stimulating factor (G-CSF) has been shown to have direct effects on the recruitment and bactericidal ability of neutrophils, resulting in improved survival of experimentally infected animals. We studied the effect of G-CSF on the course of experimental pneumonia induced by Klebsiella pneumoniae, an important gram-negative bacillary pulmonary pathogen. Using a highly reproducible murine model, we here show the paradoxical finding that mortality from infection was significantly increased when animals received G-CSF before induction of pneumonia. Administration of G-CSF promoted replication of bacteria in the liver and spleen, thus indicating an impairment rather than an enhancement of antibacterial mechanisms. By contrast, a monoclonal antibody against Klebsiella K2 capsule significantly reduced bacterial multiplication in the lung, liver, and spleen, and abrogated the increased mortality caused by G-CSF. In vitro studies showed a direct effect of G-CSF on K pneumoniae resulting in increased capsular polysaccharide (CPS) production. When bacteria were coincubated with therapeutically achievable concentrations of G-CSF, phagocytic uptake and killing by neutrophils was impaired. Western blot analysis showed three binding sites of G-CSF to K pneumoniae. Binding of 125I-G-CSF to K pneumoniae was displaced by an excess of unlabeled G-CSF, whereas an unrelated cytokine, interleukin-1alpha, did not compete with G-CSF binding to the bacteria. Thus, in this model, the direct effect of G-CSF on a bacterial virulence factor, CPS production, outweighed any beneficial effect of G-CSF on recruitment and stimulation of leukocytes.