The polypore mushroom Irpex lacteus, a new causative agent of fungal infections

Irpex lacteus, a wood-decaying basidiomycete, was isolated from a pulmonary abscess of an immunosuppressed child. This medical strain was compared morphologically and by sequencing of the ribosomal intergenic spacers with specimens from both culture collections and herbarium desiccated material. The patient was treated successfully with amphotericin B.     

DNA probe analysis for carrier detection and prenatal diagnosis of Duchenne muscular dystrophy: a standard diagnostic procedure.

Thirteen marker loci localised on the short arm of the X chromosome are available for use in genetic studies for Duchenne muscular dystrophy (DMD). This large number of probes detecting about 20 RFLPs encouraged us to set up a standard procedure using a sequence of selected probes and restriction enzymes for the diagnosis of DMD families. The application of DNA probe analysis for carrier detection and prenatal diagnosis, involving 61 pedigrees of both familial and isolated cases, has yielded the following results. Carrier detection using flanking markers was possible in more than 75% of the cases (104 out of 136 females) with a reliability of better than 98%. Prenatal diagnosis was possible in 95% of the cases (65 out of 68 proven carriers or women at risk). Twenty-three prenatal diagnoses were performed on male fetuses; 13 appeared to have a low risk for DMD (less than 1%) and thus the pregnancies continued. Seven have since come to term and the male infants have normal CK levels. The genetic distances of the loci relative to the DMD locus and their order on the short arm of the X chromosome were deduced from our total DMD family material and are not significantly different from those reported earlier. For 754 (DXS84) we found a genetic distance of 5 cM with a lod score of +12.4 and 95% confidence limits between 2 and 12 cM. Similar data were obtained for pERT87 (DXS164), suggesting that in our family material both loci are tightly linked. Multiply informative recombination showed that both 754 and pERT87 map proximal to the DMD mutations in the cases studied. The high frequency of DMD mutations and its relation to the observed instability in this part of the genome will be discussed. Unequal crossing over is proposed as one of the mechanisms contributing to the high mutation frequency.     

Studies in stress-relaxation and distensibility characteristics of small skin veins in vivo by a combined photoelectric-photographic and plethysmographic technique

Summary The phenomena of stress-relaxation and capillary outward filtration were studied in the isolated rabbit ear, perfused with blood at constant flow. The volume increase, as measured by the plethysmograph, following elevation of venous outflow pressure to 20 mm Hg for 4 min was predominantly due to capillary outward filtration in the norepinephrine constricted vascular bed (0.5 g/min). With papaverine induced dilatation (0.08 mg/min) this persistent volume increase could be attributed mainly to stress-relaxation of the veins. Engorgement of venous vessels as well as capillary outward filtration led to an increase of the ear volume that is measured by the plethysmographic technique. The photographic-photoelectric measurement of venous diameter changes was used in these experiments to distinguish intravascular from extravascular volume changes. The moduli of volume elasticity were calculated for smaller and larger veins (mean diameter 0.133 mm and 0.553 mm) with norepinephrine constriction. It has been demonstrated that the smaller veins were about seven times less distensible than the larger veins.This investigation was supported by Contract F44620-71-C-0117 of the USAF School of Aerospace Medicine, European Office of Aerospace Research (OAR), U.S. Air Force and Deutsche Forschungsgemeinschaft.This work was presented in part at the 39. Tagung der Deutschen Physiologischen Gesellschaft, Erlangen, April 1972 [Pflügers Arch. Suppl.332, R 54 (1972)].     

Mechanism(s) promoting HIV-1 infection of primary unstimulated T lymphocytes in autologous B cell/T cell co-cultures

Resting CD4(+) T cells in the lymphoid tissue (LT) are essential producers of virions at the beginning of HIV infection in vivo. We previously developed a model that allowed in vitro infection of non-prestimulated T lymphocytes in the presence of autologous B lymphocytes and complement. In this study, we try to clarify the mechanism(s) responsible for virus transmission in unstimulated autologous B cell/T cell co-cultures. Ex vivo analyses of patient plasma samples revealed that HIV was opsonized. Flow cytometry showed that opsonized virus preferentially bound to complement receptor (CR)-2 on B lymphocytes in primary B cell/T cell co-cultures. As indicated by cytokine measurements and transwell experiments, soluble factors seemed to play a minor role in enabling infection. Rather, direct interaction between B and T lymphocytes and direct binding of opsonized virus to CR2 on B cells turned out to be essential for productive infection. Antibodies blocking cell-cell adhesion inhibited p24 antigen production. An anti-CR2 antibody blocking C3d-CR2 binding also significantly reduced viral replication. Since the infection of unstimulated T cells by opsonized primary HIV isolates in the presence of B cells was highly efficient independent of the tropism of the virus, this mechanism may be critical in the pathogenesis of HIV.     

A fractal analysis of pyramidal neurons in mammalian motor cortex.

Pyramidal neurons in the mammalian cerebral cortex can be described by a fractal dimension (Mandelbrot, 1982), which is an objective, quantitative measure of the complexity of their soma/dendritic borders. In the cat, the fractal dimensions of lamina V cells, which include pyramidal tract neurons (PTN), indicate that these cells are more complex than other pyramidal neurons (PN) in the same region of motor cortex. The lamina V cells of the cat are also more complex than those in motor cortex of the monkey. Moreover, lamina III neurons in the monkey are more complex than monkey lamina V neurons. The fractal dimension of the intracortical axon collateral arborizations of the same pyramidal neurons indicated, in all cases, that the branching of these terminals is less complex than the branching of the dendrites of the same cells. In line with the observation that the fractal dimensions of some homologous cellular populations are different in different species, it is suggested that the fractal dimension and the degree of morphological complexity may relate to the requirement for the number of separable functions to be accommodated within one neuron. For example, as the size of the cortex and the number of neurons in a region increase, the opportunity exists within a given cortical zone, for individual functions to be segregated and for functional specialization to be accommodated with less morphological complexity of the individual neurons performing each of these functions.     

über die antikörperinaktivierende Wirkung der Antirheumatica

Zusammenfassung Die Antirheumatica Prednisolon, Phenylbutazon, Resochin, Natriumgentisinat und Natriumsalicylat hemmen die durch hämolytischen Hammelblutamboceptor und Komplement bewirkte Hammelbluthämolyse.Diese Wirkung der Antirheumatica kommt durch eine Inaktivierung des Amboceptors (Antikörpers) zustande. Das Komplement und die Hammelblutkörperchen werden bei diesen Versuchen von den Antirheumatica nicht beeinflußt.Es besteht eine strenge quantitative Beziehung zwischen Amboceptorkonzentration und Antirheumaticumkonzentration. Je höher die Konzentration des Amboceptors ist, um so stärkere Antirheumaticakonzentrationen sind zu seiner Inaktivierung nötig.Bezogen auf die wirksamen molaren Endkonzentrationen sind Prednisolon 8,5, Phenylbutazon 6,5, Resochin 5,0 und Gentisinsäure 1,5mal stärker wirksam als Salicylsäure.Wird der Amboceptor mit bestimmten Konzentrationen von Phenylbutazon, Natriumgentisinat oder Natriumsalicylat vorbehandelt, so kann mit diesem Amboceptor der Forssman-Schock (invers-anaphylaktischer Schock) nicht mehr beim Meerschweinchen ausgelöst werden. Phenylbutazon und Natriumgentisinat sind dabei etwa gleichstark wirksam, während Natriumsalicylat wesentlich schwächer wirkt als die beiden anderen Substanzen.     

Experimental Staphylococcus aureus arthritis in mice.

Staphylococcus aureus arthritis is usually caused by bacteremia and is highly destructive. Controlled studies on septic arthritis in humans are difficult to perform, because the time of onset of the infection is unknown. Animal models of bacterial arthritis make it possible to control important variables in experimental studies. We present a mouse model of S. aureus arthritis in which the intravenous administration of 10(7) cells of S. aureus LS-1 induced arthritis or osteitis or both within 3 weeks in 80 to 90% of the mice. Signs of arthritis emerged within the first few days after the injection. An interesting finding was that the S. aureus strain used in this study binds bone sialoprotein, a glycoprotein known to be specifically localized to bone tissue. This new model of S. aureus arthritis enables the study of the kinetics of joint destruction and the host-bacterium relationship as well as therapeutical approaches to septic arthritis and osteomyelitis.