Tumor-suppressor gene products in cell contacts: the cadherin-APC-armadillo connection

Various structural components of intercellular junctions have recently been found to represent (or be related to) products of tumor-suppressor genes. The tumor-suppressor gene product adenomatous polyposis coli (APC) binds to beta 2-catenin (homologous to the product of Drosophila armadillo), which is cytoplasmically associated with the cell adhesion molecule E-cadherin.     

Enzymatic examination of citrate-isocitrate accumulation in yeasts

The activities of the enzymes citrate synthase, aconitate hydratase, isocitrate dehydrogenase and isocitrate lyase in cell homogenates of n-paraffin grown citrate plus isocitrate accumulating yeasts (C. lipolytica high rate accumulating strain and C. guilliermondii low rate accumulating strain) were determined. It is shown that the activities of the enzymes decline after transition from tropho- to idiophase and remain constant with exception of isocitrate lyase which diminishes slowly. The decline in activity of the isocitrate lyase was greatest in the cells of C. guilliermondii. It is discussed that the differences of the enzymatic activities in the tropho- and idiophase, resp. may be artefacts due to changes in the structure of cellular envelope, but that the decline of lyase activity in the idiophase could be one factor determining the rate of citric- and isocitric acid overproduction. The diminishing of isocitrate lyase in the course of idiophase is interpreted as example of a disappearing enzyme no further needed for normal function of the cells.     

Basic oxygen operations at August Thyssen Hutte

Germany’s newest basic oxygen steelmaking shop—its design and operation, with particular emphasis on vessel lining and nozzle design.     

A modified technique of the triple pelvic osteotomy: early results

A modification of the triple pelvic osteotomy for children over 8 years and the young adult is described. The results of the first 32 cases are reviewed. These show that the indications for the operation can be widened so that not only primary dysplasias but also subluxated or dislocated hips with secondary dysplasia can be operated on successfully. The operation is done in two stages. At first the patient is lying prone. The osteotomy of the ischial ramus is done dorsally by cutting the connection between the sciatic notch and obturator foramen immediately behind and below the acetabulum. In the second stage, with the patient lying supine, the pubic and the iliac osteotomy are performed rather circular and parallel to the hip joint. These modifications have several advantages: (a) the operator has a direct field of view at all times; (b) the osteotomy is performed close to the acetabulum, thus allowing a great amount of lateral rotation and medial displacement of the acetabulum, thereby providing good coverage of the femoral head by hyaline cartilage; and (c) the ischial ramus and its ligaments to the sacrum are left intact, leading to greater stability of the pelvis and spine.     

The neutron component of two high-energy photon reference fields

The 4.4 MeV photon reference field described in ISO 4037 is produced by the (12)C(p,p')(12)C (E(x) = 4.4389 MeV) reaction using a thick elemental carbon target and a proton beam with an energy of 5.7 MeV. The relative abundance of the isotope (13)C in elemental carbon is 1.10%. Therefore, the 4.4 MeV photon field is contaminated by neutrons produced by the (13)C(p,n) (13)N reaction (Q = -3.003 MeV). The ambient dose equivalent H*(10) produced by these neutrons is of the same order of magnitude as the ambient dose equivalent produced by the 4.4 MeV photons. For the calibration of dosemeters, especially those also sensitive to neutrons, the spectral fluence distribution of these neutrons has to be known in detail. On the other hand, a mixed photon/neutron field is very useful for the calibration of tissue-equivalent proportional counters (TEPC), if this field combines a high-linear energy transfer (LET) component produced by low-energy neutrons and a low-LET component resulting from photons with about the same ambient dose equivalent and energies up to 7 MeV. Such a mixed field was produced at the PTB accelerator facility using a thin CaF(2) + (nat)C target and a 5.7 MeV proton beam.