Diphtheria toxin fused to granulocyte-macrophage colony-stimulating factor eliminates acute myeloid leukemia cells with the potential to initiate leukemia in immunodeficient mice, but spares normal hemopoietic stem cells

We studied the cell kill induced by granulocyte-macrophage colony-stimulating factor (GM-CSF ) fused to Diphtheria Toxin (DT-GM-CSF ) in acute myeloid leukemia (AML) samples and in populations of normal primitive hemopoietic progenitor cells. AML samples from three patients were incubated in vitro with 100 ng/mL DT-GM-CSF for 48 hours, and AML cell kill was determined in a proliferation assay, a clonogenic assay colony-forming unit-AML (CFU-AML) and a quantitative long-term bone marrow (BM) culture ie, the leukemic-cobblestone area forming cell assay (L-CAFC). To measure an effect on cells with in vivo leukemia initiating potential DT-GM-CSF exposed AML cells were transplanted into immunodeficient mice. In two out of three samples it was shown that all AML subsets, including those with long-term abilities in vivo (severe combined immunodeficient mice) and in vitro (L-CAFC assay) were reduced in number by DT-GM-CSF. Cell kill induced by DT-GM-CSF could be prevented by coincubation with an excess of GM-CSF, demonstrating that sensitivity to DT-GM-CSF is specifically mediated by the GM-CSF receptor. Therefore, binding and internalization of GM-CSF probably occur in immature AML precursors of these two cases of AML. The third AML sample was not responsive to either GM-CSF or DT-GM-CSF. The number of committed progenitors of normal bone marrow (burst-forming unit-erythroid, colony-forming unit granulocyte- macrophage, and cobble stone area forming cell [CAFC] week 2) and also the number of cells with long-term repopulating ability, assayed as week 6 CAFC, were unchanged after exposure to DT-GM-CSF (100 ng/mL, 48 hours). These studies show that DT-GM-CSF may be used to eliminate myeloid leukemic cells with long-term potential in vitro and in immunodeficient mice, whereas normal hemopoietic stem cells are spared.     

Growth of Yb∶YAB Crystal and Its Laser Performance

Ｓｅｌｆ ｆｒｅｑｕｅｎｃｙ ｄｏｕｂｌｉｎｇｓｉｎｇｌｅｃｒｙｓｔａｌｓａｒｅｏｎｅｋｉｎｄｏｆｔｈｅｐｏｌｙｆｕｎｃｔｉｏｎｍａｔｅｒｉａｌｓ .Ｔｈｅｙｐｏｓｓｅｓｓｂｏｔｈｌａｓｅｒｃｒｙｓｔａｌｐｒｏｐｅｒｔｉｅｓａｎｄｎｏｎ ｌｉｎｅａｒｃｒｙｓｔａｌｐｒｏｐｅｒｔｉｅｓ .Ｔｈｅｓｏｌｉｄｓｔａｔｅｌａｓｅｒｓｆａｂｒｉｃａｔｅｄｂｙｔｈｅｓｅｍａｔｅｒｉａｌｓｈａｖｅｓｉｍｐｌｅｓｔｒｕｃ ｔｕｒｅａｎｄａｒｅｅａｓｙｔｏｏｐｅｒａｔｅ .Ｗｉｔｈｔｈｅｄｅｖｅｌｏｐ ｍｅｎｔｏｆｄｉｏｄ…     

Stranger in Turkey

The author, a professor of nephrology, reports some impressions of his 7-year stay in Turkey. He worked at the Ege University in Izmir, traditionally one of the most 'western' cities. He and his wife, who gave unpaid assistance to dialysis patients, attempted to integrate into Turkish society as fully as possible. They traversed the country in weekends and holidays and introduced as many Dutch guests as they could to the unique archeological treasures, the magnificent nature and the extremely friendly population. Work at the university focused increasingly on cultivating a critical attitude with regard to the self, society and the trends and commercialization of medicine in Turkey and in the rest of the world. Self-reliance, also, had to be strengthened. Although this contravened the authority-based Turkish educational system, the efforts were clearly appreciated and even stirred enthusiasm in many of the younger people. There is no doubt that a foreign worker is regarded much more favourable in Turkey than in the Netherlands.     

Effect of mechanical treatment on healing after third molar extraction

The aim of this study was to determine the effect of subgingival scaling and root planing on healing of the distal surface of second molars following extraction of third molars. Twenty-eight patients with contralateral erupted third molars and pocket depths greater than or equal to 3 mm on the distal surface of the second molars participated in this study. Measurements of supragingival bacterial plaque, bleeding on probing, pocket depth, and relative attachment level were performed at baseline and 2 months after treatment. Extraction of contralateral third molars was carried out simultaneously. The experimental site received thorough scaling and root planing of the distal surface of the second molar, while the control site received extraction alone. Experimental sites showed significant improvement in all clinical parameters assessed compared to the control sites. In conclusion, periodontal lesions on the distal of second molars can be significantly improved following scaling and root planing after extraction of third molars.     

Comparison of usefulness of computer assisted continuous 48-h 3-lead with 12-lead ECG ischaemia monitoring for detection and quantitation of ischaemia in patients with unstable angina

AIMS: The selection of ECG leads used for ST monitoring may influence detection and quantitation of ischaemia. METHODS: We compared on-line continuous 48-h 12-lead against 3-lead ST monitoring in 130 unstable angina patients (Mortara. ELI-100). Onset and offset of ST episodes were defined by the lead with the first > or = 100 microV ST change relative to baseline and the lead with the latest return to baseline ST level, respectively. ST episodes were calculated for 12 leads and 3 leads (V2, V5, III) separately. RESULTS: ST episodes were detected in 88 patients (77%) by 12-lead and in 71 patients (62%) by 3-lead ST monitoring (P < 0.02). The median number (25.75%) of episodes/patient was 1 (0.3) for 3-lead and 2 (1.6) for 12-lead (P < 0.0001). The total duration of ischaemia detected during 12-lead far exceeded 3-lead monitoring: 12.3 (1, 58.2) and 1.7 (0, 23.3) min respectively (P < 0.0001). The probability of recurrent ischaemia declined most during the first 24 h of monitoring. After a period without ST changes of 1, 12, 24 and 36 h, the probabilities of recurrent ischaemia were 63, 31, 14 and 9%, respectively. CONCLUSIONS: Continuous 12-lead ST monitoring increases detection rate and duration of ST episodes compared to 3-lead ST monitoring. The use of continuous 12-lead ECG monitoring devices on emergency wards and coronary care units is recommended.     

Production of surfactant protein C in the baculovirus expression system: the information required for correct folding and palmitoylation of SP-C is contained within the mature sequence

Surfactant protein C (SP-C) is synthesized in the alveolar type II cells of the lung as a 21 kDa propeptide which is proteolytically processed to a 4.2 kDa mature active form. The main function of this extremely hydrophobic protein is to enhance lipid insertion into the air/liquid interface in the lung upon inhalation. This is necessary to maintain a relatively low surface tension at this interface during breathing. In this report we describe the production of mature human SP-C in the baculovirus expression system. The recombinant protein contains a secondary structure with a high alpha-helical content (73%), comparable to native SP-C, as determined by circular dichroism and attenuated total reflection Fourier transform infrared analysis. The expressed protein is a mixture of dipalmitoylated (15%) and non-palmitoylated SP-C. This suggests that the information required for palmitoylation is contained within the sequence of the mature protein. The activity of the protein to insert phospholipids into a preformed monolayer of lipids at an air/liquid interface was determined with a captive bubble surfactometer. Recombinant SP-C significantly reduced the surface tension at the air/liquid interface during dynamic expansion and compression. We conclude that correctly folded, dipalmitoylated and active SP-C can be expressed in the baculovirus expression system. Our results may facilitate investigations into the relation between structure and function of SP-C and into protein palmitoylation in general.