Parameters of the two generator discrete elementary groups : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Mathematics at Massey University, Albany, New Zealand

Let f, g be elements of M, the group of Möbius transformations of the extended complex plane Ĉ = C U ∞. We identify each element of M with a 2 × 2 complex matrix with determinant 1. The three complex numbers, β(f) = tr2 (f) - 4,β(g) = tr2 (g) - 4,γ(f,g) = tr[f,g] - 2, define the group ‹f,g› uniquely up to conjugacy whenever γ(f,g) ≠ 0; where tr(f) and tr(g) denote the traces of representive matrices of f and g respectively, [f,g] denotes the multiplicative commutator fgf-1 g-1 . We call these three complex numbers the parameters of ‹f,g›. This thesis is concerned with the parameters of discrete and elementary subgroups of M

SPONTANEOUS RELEASE OF T-CELL RECEPTORS FOR ALLOANTIGENS : I. RECOGNITION OF ALLOANTIGENS AND RECEPTOR RELEASE DYNAMICS

In vitro cultivation of murine spleen cells resulted in a spontaneous release of receptors for alloantigens. This was revealed by the capacity of cell-free culture supernates to recognize alloantigens as measured in the PAR assay. Qualitatively, recognition responses obtained with these supernates reproduced faithfully those found with the corresponding cells. Large amounts of receptors were released by untreated spleen cells and by spleen cells treated with a rabbit antimouse immunoglobulin serum and complement, smaller amounts were released by bone marrow cells, and native thymus cells released none. Spleen cells from nude mice and spleen cells from normal mice treated with anti-θ serum and complement showed no release of receptors. It was concluded that receptors active in the PAR test were of T-cell origin. Release of T-cell receptors was found to be discontinuous and proceeded in waves. The amount of released receptors depended on the number of cells cultivated. Release occurred at 37°C but not at 4°C. Interaction with antigen, however, was temperature-independent. In contrast to T-cell receptors, a release of H-2 antigens could not be detected with the culture conditions employed

QUANTITATIVE STUDIES ON ANTIGENIC RECOGNITION : I. IMMUNOLOGICAL AND NONIMMUNOLOGICAL PARAMETERS OF THE RESPONSE

Lymphoid cells from normal animals from two genetically alien but isogenic strains of mice or rats elaborated a factor into the medium during in vitro cultivation. Similarly, lymphoid cells from specifically presensitized animals mixed and cultivated with donor-type lymphoid cells, as well as normal or specifically immunized mouse spleen cells exposed to heterologous red blood cell antigens, formed this factor. Culture supernatants of genetically identical lymphoid cells lacked activity. This factor was measured by its ability to induce accumulations of polymorphonuclear cells following injection into the skin of normal hamster hosts. Gentle trypsinization of excised 24 hr cutaneous reactions permitted quantitative estimation of the number of polymorphonuclear cells accumulated and, therefore, of the activity of the factor. The factor present in culture fluids could be defined as a product of antigenic recognition (PAR). PAR was formed only when immunologically competent cells were exposed to cells carrying histocompatibility antigens of recognizable foreignness. This view was based chiefly on the observation that, whereas lymphoid cells from specifically tolerant mice failed to recognize the paralytogen, they did recognize antigens of an unrelated mouse strain. In addition, immunocompetence was of paramount importance, since cocultivation of immunologically incompetent, yet strongly incompatible, rat thymocytes did not result in the formation of PAR. Formation of PAR was observed in very simple media. A source of energy and a suitable culture vessel were found to be the only essential nonimmunological factors for PAR to be elaborated. The presence of inhibitors of glycolysis in the medium during cultivation of mixtures of immunocompetent cells of disparate origin severely inhibited the recognition process. With cell mixtures of the immunological one-way variety, treatment of aggressor cells with inhibitors of glycolysis or of protein synthesis interfered with antigenic recognition, whereas similar treatments of the target cells were without effect. The findings presented sustain the thesis that the elaboration of PAR is a very early event in the immune process

Potential impact of subject-based risk factor control on periodontitis

Aims : To assess the potential impact of the control of subject-based modifiable risk factors on periodontitis. Background : Cross-sectional and longitudinal data from epidemiological research indicate that risk factors can be identified and, if modified, may improve both periodontal conditions and the outcome of treatment. Material and Methods : A search was conducted to identify factors involved in the etiology and pathogenesis of periodontal diseases. The factors identified were separated into modifiable and non-modifiable, and control of the subject-based modifiable risk factors were further analyzed. Results : The analysis was limited to the influence of the control of the remaining modifiable subject-based risk factors. It was observed that most of the subject related risk factors were hitherto not validated in controlled intervention studies. Therefore, the evidence for the efficacy of risk factor control had to be based on results from cohort studies. While the control of most of the modifiable risk factors for periodontitis was not tested, some evidence suggested that smoking cessation may retard the progression of periodontitis. Conclusions : Although only limited evidence was available, it appeared reasonable to suggest that second to the removal of the bacterial biofilm, smoking cessation was the most important measure in the management of periodontitis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75692/1/j.1600-051X.2005.00798.x.pd

Verlängerung des kongenital kurzen Femurs (PFFD) mittels Hybridfixateur unter Einbeziehung des Kniegelenks

Zusammenfassung: Hintergrund: Kontrakturen und Luxationen in Knie- und Hüftgelenk sind bekannte Komplikationen bei der Verlängerung des proximalen fokalen Femurdefekts (PFFD). Insbesondere ist das Kniegelenk wegen der fehlenden oder insuffizienten Kreuzbänder beim PFFD gefährdet. Achsenabweichungen muss ebenfalls besondere Beachtung geschenkt werden. Patienten und Methoden: Bei 4Patienten (Alter 2,5-11Jahre) mit PFFD (Pappas-KlasseIII (1Patient), KlasseVII (3Patienten)) wurden 5Verlängerungen mit Achsenkorrektur durchgeführt. Es wurde ein kniegelenküberbrückender Fixateur externe (Monotube, Triax®) verwendet, der Tibia und Femur mit einem Scharniergelenk verbindet und das Kniegelenk vor Kontraktur oder Luxation schützt. Die Verlängerungen lagen zwischen 3 und 11cm. Resultate: Alle Patienten erreichten nach Verlängerung die vorherige Knie- und Hüftbeweglichkeit. Eine Hüftgelenkkontraktur kann während der Verlängerung die Einbeziehung des Hüftgelenks in das Fixateursystem notwendig machen. Dies war bei den in diesem Beitrag beschriebenen 4Patienten nicht erforderlich. Schlussfolgerung: Vier konsekutive Verlängerungen bei angeborenem longitudinalem Femurdefekt erfolgten unter Luxationsschutz des Kniegelenks durch ein kniegelenküberbrückendes Flexionsbewegungen erlaubendes Fixateursystem. Bei diesen Patienten konnte eine Kontraktur bzw. Luxation vermieden werden. Wir denken, dass ein solches System bei entsprechenden Verlängerungen in Betracht gezogen werden sollt

Histoire de packs ou d'enveloppes thérapeutiques avec un patient dément

Les patients déments, comme les patients psychotiques, peuvent présenter des angoisses d'intrusion ou de morcellement. L'histoire de Monsieur D témoigne du fait que les packs permettent de diminuer cette souffrance en offrant une expérience intense de contenance et d'unité. Malgré une démence avancée, Monsieur D a ainsi pu intégrer progressivement cette enveloppe maternante et thérapeutique pour recréer le lien à l'autre et le lien à lui-même