Long-term effects of short-term retinal bleb detachments in rabbits

PURPOSE: To examine the effects of saline-induced bleb detachments in rabbit retina. METHODS: Retinal bleb detachments were produced by the injection of 50 microl of balanced salt solution (BSS) into the subretinal space of one eye of each of six rabbits using a glass pipette with a flat tip, 50 microm in diameter. The retina was examined by biomicroscopy, scanning laser ophthalmoscopy (SLO), auto-fluorescence and simultaneous fluorescein and indocyanine green (ICG) angiography. Histological examination was carried out at 1, 2, 3 and 4 months after surgery. RESULTS: All rabbits showed leakage of fluorescein for at least a day after detachment, but within 1 month the leakage ceased. ICG staining developed gradually at the level of the RPE or Bruch's membrane near sites of previous staining. Lipofuscin fluorescence also developed gradually around areas of staining. Histology revealed the source of the excessive lipofuscin to be in the RPE layer, especially in cells migrating away from Bruch's membrane. CONCLUSIONS: Short-term bleb detachments cause a transient breakdown in the blood-retinal barrier, long-term ICG staining at or deep to the RPE layer, hyperlipofuscinosis and migration of the RPE. The abnormal lipofuscin accumulation is apparent on fluorescence ophthalmoscopy and can be confused with markers such as green fluorescent protein.     

Cytogenetic peculiarities in chronic myelogenous leukemia

Cytogenetic investigations were performed in 185 patients with chronic myelogenous leukemia (CML) at all stages of the disease; 166 patients were Ph positive-159 (95.8%) of these showing the standard Ph translocation, and 7 (4.2%) variant translocations-17 patients were Ph negative. In 2 patients the cytogenetic analysis was unsuccessful. Additional aberrations were found in 40 (24.1%) of the Ph-positive patients. Nine (52.9%) of the Ph-negative patients showed chromosome anomalies. Besides the well known nonrandom abnormalities (-7, +8, i(17q), +19, +Ph) we found a high frequency of clones with rare or not yet described structural rearrangements--in 14 cases (34.2%) of the Ph-positive patients and in 2 cases (20%) of the Ph-negative patients with other chromosome abnormalities. The clinical significance of these findings is discussed.     

Connexin 43 expression of foreign body giant cells after implantation of nanoparticulate hydroxyapatite

In bone a role of connexin 43 has been implicated with the fusion of mononuclear precursors of the monocyte/macrophage lineage into multinucleated cells. In order to investigate the putative role of connexin 43 in formation of bone osteoclast-like foreign body giant cells which are formed in response to implantation of biomaterials, nanoparticulate hydroxyapatite had been implanted into defects of minipig femura. After 20 days the defect areas were harvested and connexin 43 expression and synthesis were investigated by using immunohistochemistry, Western Blot, and in situ hybridization within macrophages and osteoclast-like foreign body giant cells. Morphological analysis of gap junctions is performed ultrastructurally. As shown on protein and mRNA level numerous connexin 43 positive macrophages and foreign body giant cells (FBGC) were localized within the granulation tissue and along the surfaces of the implanted hydroxyapatite (HA). Besides, the formation of FBGC by fusion of macrophages could be shown ultrastructurally. Connexin 43 labeling observed on the protein and mRNA level could be attributed to gap junctions identified ultrastructurally between macrophages, between FBGC, and between FBGC and macrophages. Annular gap junctions in the cytoplasm of FBGC pointed to degradation of the channels, and the ubiquination that had occurred in the course of degradation was confirmed by Western blot analysis. All in all, the presently observed pattern of connexin 43 labeling refers to an functional role of gap junctional communication in the formation of osteoclast-like foreign body giant cells formed in response to implantation of the nanoparticulate HA.     

A probabilistic algorithm for robust interference suppression in bioelectromagnetic sensor data

Magnetoencephalography (MEG) and electroencephalography (EEG) sensor measurements are often contaminated by several interferences such as background activity from outside the regions of interest, by biological and non-biological artifacts, and by sensor noise. Here, we introduce a probabilistic graphical model and inference algorithm based on variational-Bayes expectation-maximization for estimation of activity of interest through interference suppression. The algorithm exploits the fact that electromagnetic recording data can often be partitioned into baseline periods, when only interferences are present, and active time periods, when activity of interest is present in addition to interferences. This algorithm is found to be robust and efficient and significantly superior to many other existing approaches on real and simulated data.     

Monosomy 7 associated with pediatric acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS): successful management by allogeneic hematopoietic stem cell transplant (HSCT)

Pediatric acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) with monosomy 7 is associated with poor disease-free survival when treated by conventional chemotherapy, immunosuppression or supportive measures. Hematopoietic stem cell transplant (HSCT) may improve outcomes; however, data to support this are limited. To better understand the curative potential of HSCT in these patients, all cases of AML and MDS with monosomy 7 treated by two transplant programs (1992 to present) were reviewed. A total of 16 patients were treated, all by allogeneic HSCT. Primary diagnoses were MDS (N = 5), therapy-related MDS (N = 3), AML (N = 5) and therapy-related AML (N = 3). In all, 11 patients (69%) survive event-free at 2 years with median follow-up of 986 days (range 330-2011 days). Toxicity caused deaths of the five nonsurviving patients, four of whom were transplanted with active leukemia. Allogeneic HSCT is effective therapy for childhood AML and MDS associated with monosomy 7, particularly for patients with AML in complete remission and MDS.     

Stromafreie Hämoglobinlösung und isolierte Extremitätenperfusion

Zusammenfassung Die stromafreie Hämoglobinlösung in pyridoxalierter Form wurde unter den Versuchsbedingungen der isolierten Extremitätenperfusion mit hämodilutiertem Blut verglichen. Die Versuche erfolgten an Schäferhundbastarden. Der pH-Wert im Gewebe und im Perfusat zeigte ebenso wie die Sauerstoffspannung ähnliche Kurvenverläufe ohne signifikante Unterschiede mit ausreichendem Sauerstoffangebot in der Peripherie. Die untersuchten Stoffwechselparameter wie Lactat, Pyruvat, ATP und CP ließen auf ein überwiegend aerobes Stoffwechselverhalten schließen. Unter den gegebenen Versuchsbedingungen der isolierten Extremitätenperfusion war die stromafreie Hämoglobinlösung (SFHb-PLP) hämodilutiertem Blut (Hk 18) als Perfusat vergleichbar und als alleiniger Sauerstoffträger einsetzbar. Histomorphologisch konnten keine nennenswerten Schäden an der perfundierten Extremität bzw. am Gesamtorganismus festgestellt werden.

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Stroma-free hemoglobin solution and isolated extremity perfusion

Summary Pyridoxylated stroma-free hemoglobin solution was compared to hemodiluted blood in extremity perfusion of mongrel dogs. pH-values in tissue and in perfusate as well as oxygen tension showed no significant difference, and oxygen supply to the periphery was sufficient. Measurement of lactate, pyruvate, ATP and CP demonstrated domination of aerobic metabolism. We proved that stroma-free hemoglobin solution (SFHb-PLP) can substitute hemodiluted blood (Hk 18) in isolated extremity perfusion. Metabolic results were confirmed by histological examination where no tissue alterations could be found in the perfused extremity or the whole body system.

     

Etude de la polycondensation linéaire de polymères précurseurs α,ω-bifonctionnels avec des agents de couplage bifonctionnels de faible masse molaire

Chain extension reactions involving α,β-bifunctional precursor polymers and bifunctional coupling agents of low molecular weight were investigated both theoretically and experimentally. The number and weight molecular weight distributions were calculated, and computer simulations were performed, neglecting the weight of the coupling agent with respect to that of the precursor polymer. Examples of such chain extension reactions include the polycondensation of “living” α,β-dicarbanionic polystyrene with 1,4-bis(bromomethyl)benzene, and the reaction of poly(oxyethylene)glycol with a low-molecular-weight diisocyanate. The characterization of the resulting polymers yields results that are in satisfactory agreement with the theoretical expectation.     

Syringomyelie und Trauma

Zusammenfassung Die Ausarbeitung von 386 Krankengeschichten von Syringomyeliekranken ergibt, daß 40 Patienten einen schweren Unfall erlitten hatten, bevor die ersten Krankheitssymptome auftraten. Eine auslösende Wirkung des Traumas wird bei 24 Kranken angenommen.Die Untersuchungen zeigen, daß möglicherweise auch rezidivierende Mikrotraumen durch schwere körperliche Arbeit die klinische Manifestation der Syringomyelie fördern können. Dafür sprechen statistische Erhebungen:Zwei Drittel der Männger gingen einer schweren körperlichen Arbeit nach, dagegen nur ein Drittel eines Vergleichskollektivs. Diese Bevorzugung läßt sich in Unterfranken sowohl in kleinen als auch in großen Ortschaften nachweisen. Das Geschlechtsverhältnis Männer zu Frauen beträgt 2 zu 1. Ähnliche Beobachtungen wie in Würzburg werden bei der Bearbeitung der Unterlagen von 5 anderen Universitätskliniken gemacht.Es wird diskutiert, ob eine Syringomyelie häufig erst dann neurologische Ausfälle macht, wenn zusätzlich zur Anlage im Laufe des Lebens exogene Faktoren auf das Rückenmark einwirken.Herrn Prof. Dr. Schaltenbrand zum 75. Geburtstag gewidmet.     

Isolated extremity perfusion with DTIC. An experimental and clinical study

Dacarbazine (DTIC) was used for isolated perfusion of extremities in dogs and man. In the animal experiment perfusions with DTIC at dosages up to 100 mg per kg of extremity weight were well tolerated. The concentration of DTIC in the perfusate ranged from 70 to 400 micrograms/ml without evidence for formation of metabolites. Electron microscopy, performed 14 days later, revealed a decrease of glycogen in striated muscle cells. Vascular damage was not observed. Five patients with advanced malignant melanoma or soft tissue sarcoma of the extremities were treated by isolation perfusion with 75 to 133 mg DTIC per kg of extremity at 40 degrees C for 60 minutes. A tumor regression of at least 30% was observed.