Increase of nucleoid size with increasing age of hyphal region in vegetative mycelia of Streptomyces granaticolor

In mycelia of Streptomyces granaticolor grown in liquid cultures the distribution of DNA was surveyed by staining and autoradiographic methods. The frequency of stained nucleoids was rather similar in young and old hyphal regions. However, the size of the nucleoids increased with the age of a hyphal region. The degree of heterogeneity in nucleoid size was particularly high during slow growth. In the autoradiograms silver grains (³H-thymidine label) were also heterogeneously distributed along the hyphae. Calculation of the average number of silver grains per nucleoid revealed that the amount of DNA per nucleoid was 1.6 times higher in the more distant subapical regions than within the 35 μm long apical region. From a chase experiment it became obvious that the DNA segregated in a normal manner only within the apical region. When the chase lasted for one doubling time, the frequency of silver grains was reduced to 50% only within the about 30 μm long apical region. The label incorporated subapieally remained almost constant, therefore, indicating a lack of normal segregation. Only about 10% of the label was lost by branching. The lack of segregation of sister nucleoids after repeated rounds of replication was found to be responsible for the increase of nucleoid size within subapieal hyphal regions.     

Antilymphocytic antibodies and bone marrow transplantation. XI. Evidence that reduced Thy-1 expression in Thy-1.1 mice prevents suppression of graft-versus-host disease with anti-Thy-1 monoclonal antibodies

Considerable variations in the suppression of graft-versus-host disease with monoclonal anti-Thy-1 antibodies were found to relate to substantial differences noted in the expression of mouse Thy-1 marker on lymph node and spleen cells of Thy-1.1 (AKR/J, C57BL/6.Thy-1.1) and Thy 1.2 (AKR/Cu, C57BL/6) mice. Thy-1.1 mice showed a population of 22% (AKR/J) or 13% (C57BL/6-Thy-1.1) of Thy-1 negative cells among peripheral T cells carrying Ly-1 marker. This was in sharp contrast with Thy-1.2 mice, where as expected practically all peripheral T cells expressed both Thy-1 and Ly-1. Double-marker analysis on FACScan revealed that the Thy-1-/Ly-1+ cell population identified in Thy-1.1 but not in Thy-1.2 mice doubtless represents T cells because they express CD3 and either the L3T4 (CD4) or Lyt2 (CD8) phenotype. Using quantitative fluorescence-measurement techniques, it was found in addition that the Thy-1 antigen-binding sites on Thy-1+ cells from Thy-1.1 mice are considerably fewer than those present in Thy-1.2 mice. In fact, the Thy-1 antigen-binding sites approximate the level of Ly-1 density. Consequences of the reduced expression of Thy-1 became apparent in vivo: (1) lymphnode and splenic T cell areas in Thy-1.1 mice were clearly less depleted when Thy-1.1 and Thy-1.2 mice had been injected with rat IgG2b anti-Thy-1 mAb; and (2) GvHD was prevented completely in fully mismatched mice by anti-Thy-1 mAb if the donor mice expressed Thy-1.2 but was barely delayed if the donors expressed Thy-1.1. Thus the present study provides a transplantation model for comparing differences in T antigen density and their consequences for antibody-induced immunosuppression.     

Nonfluent aphasia in a patient with Waldenstrom's macroglobulinemia.

Waldenstrom's macroglobulinemia (WM) is an uncommon low-grade lymphoma. Cognitive impairment due to central nervous system infiltration by lymphoplasmocytoid cells (Bing-Neel syndrome) has been rarely reported. We describe a 54-year-old man who was referred to a memory disorder clinic with a 9-month history of clinically obvious nonfluent aphasia and WM. He underwent extensive neuropsychological testing, clinical examination and structural and functional brain imaging. The diagnosis of the diffuse form of the Bing-Neel syndrome was supported by abnormal lymphoid cells found in the cerebrospinal fluid. Structural and functional brain imaging revealed impairment of brain areas due to white matter changes and subsequent functional deficits mimicking the neuropsychological syndrome encountered in progressive nonfluent aphasia. The diffuse form of Bing-Neel syndrome and neurological deficits are assumed to be the result of leptomeningeal infiltration by malignant cells and/or neoplastic vascular obstruction.     

Prefrontal cortex dysfunction and depression in atypical parkinsonian syndromes.

Depressive symptoms are common in patients with neurodegenerative disorders. Imaging studies suggest that a disruption of frontal-subcortical pathways may underlie depression associated with basal ganglia disease. This pilot study tested the hypothesis that frontal dysfunction contributes to depression associated with multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Depressed patients with MSA (n = 11), PSP (n = 9), and age-matched controls (n = 25) underwent measures of cerebral glucose metabolism applying positron emission tomography with (18)F-fluorodeoxyglucose. Regional metabolism in the patient groups was compared to the normal subjects using the voxel-based statistical parametric mapping. Depressive symptom severity (Hamilton Depression Rating) and degree of locomotor disability (Hoehn & Yahr) were assessed in the patient groups. The association between prefrontal metabolism and the occurrence of depressive symptoms and the degree of locomotor disability was investigated. When compared to controls, MSA patients revealed significant metabolic decreases in bilateral frontal, parietal, and cerebellar cortex and in the left putamen. In PSP patients, significant hypometabolism was demonstrated in bilateral frontal cortex, right thalamus, and midbrain. Depression severity but not the patients' functional condition was significantly associated with dorsolateral prefrontal glucose metabolism in both patient groups. The findings of this pilot study support the hypothesis that depressive symptoms in MSA and PSP are associated with prefrontal dysfunction.     

Neurotensin-like immunoreactivity in presumptive baroreceptor neurons innervating the guinea pig carotid sinus

This study was carried out to determine the ultrastructure and origin of previously described neurotensin-like immunoreactive (NT-LI) nerve fibres in the wall of the carotid sinus of the guinea pig. In our degeneration experiments, these NT-LI axons were unaffected by surgical sympathectomy but disappeared in response to transection of the carotid sinus nerve, thus suggesting a sensory origin. This assumption could be supported by combined retrograde tracing and immunohistochemistry. Primary afferent neurons of the sensory glossopharyngeal (petrosal) ganglion projecting to the carotid sinus were identified by injecting the retrograde fluorescent tracer, Fluoro-Gold, into the sinus wall, and some of these neurons displayed NT-LI. Within the carotid sinus, the terminals of these NT-LI sensory neurons exhibited ultrastructural features characteristic of baroreceptor endings, i.e. axonal swellings filled with mitochondria and closely associated to elastin. However, many endings also fulfilling the ultrastructural criteria for baroreceptors were devoid of immunolabelling. Thus, we conclude that the NT-LI terminals constitute a subgroup rather than the entire population of baroreceptor endings within the guinea pig carotid sinus. With respect to the established pharmacological effects of NT in guinea pig, we propose an involvement of NT-LI fibres in the modulation of baroreception at the peripheral level.     

The effect of wire configuration on the stability of the Ilizarov external fixator.

The stability of the basic unit for fixation of the Ilizarov external fixation system was tested in several loading modes. The effects of varying the number of wires and the orientation of wire placement were studied. The fixation units were mounted on a plastic, simulated, long bone and tested by loading in several directions. The Ilizarov fixation ring was found to be relatively stiff in axial compression and torsion. Its stiffness in this mode was directly proportional to the number of wires in the system and independent of the configuration of wire placement. Loading in bending and in shear provided much lower levels of stiffness, and this was dependent on the angles formed between the wires. The addition of a wire at a minimum distance of 4 cm from the primary ring significantly improved bending stiffness. The use of opposed olive wires also improved shear stiffness.     

Über ein Verfahren der Radikaloperation freier Schenkelbrüche

Ohne Zusammenfassung (Mit 6 Abbildungen im Text und 7 stereoskopischen Bildern in Mappe.)