Löusungsverhalten niedermolekularer polydimethylsiloxane mit methylendgruppen

Poly(dimethyl siloxanes) with methyl endgroups undergo association in chloroform and toluene according to measurements by vapour pressure osmometry. The virial coefficients measured in bromocyclohexane point to a structure of an interrupted helix. Accordingly, the values of [η]/M^0,5 strongly drop down at low molecular weights.     

Polykondensationen mit α-aminocarbonsäureestern. I. Orientierende papierchromatographische untersuchungen

Glycine esters undergo polycondensation under the action of different catalysts at temperatures between 0 and 80°C, whereas esters of substituted amino acids need higher reaction temperatures. High catalytic activity is exhibited by acids like HOHC as well as by compounds like SnCl₄, PCl₅, and BiCl₃. The R_f-values of some amino acid derivatives in different media are reported.     

Autogenous leukocyte migration in human malignancies.

The leukocyte migration test (L.M.T.) was utilized for in vitro study of cell-mediated immunity in human malignancies. Tumor cells and autogenous peripheral blood leukocytes from 35 patients with various malignancies, who were not receiving any therapy, were studied. There was inhibition of the migration of the autogenous leukocytes in 18 of 20 patients with resectable tumors who had no evidence of hematogenous metastasis or widespread disease, whether the local lymph nodes were involved or not. However, the migration of autogenous leukocytes from patients with hematogenous metastasis or widespread disease was not inhibited in 14 of 15 patients whether the tumor cells were obtained from the primary or metastatic sites. The utilization of fresh, frozen-thawed (dead) tumor cells, or tumor cell extracts gave almost the same results. This could indicate that localized tumors were recognized as antigenic by the presensitized autogenous leukocytes, resulting in the inhibition of the migration. This state seemed to disappear in the presence of hematogenous metastasis. Normal tissues did not inhibit the migration of the autogenous leukocytes, presumably because these had not been recognized as foreign or antigenic.     

Progressive enlargement of cavity within melanoma masquerading as iris cyst

PURPOSE: To describe progressive enlargement of intralesional cavities within a mass that masqueraded clinically as an iris pigment epithelial cyst for 2 years but later proved to be a melanoma. METHODS: An 81-year-old woman developed asymptomatic focal elevation of the iris, and ultrasound biomicroscopy showed a fluid-filled mass that was interpreted as an iris pigment epithelial cyst. Over a 2-year period of observation, the cavity enlarged from 0.7 to 10 mm, and the solid component enlarged from approximately 6 to 16 mm basal dimension. RESULTS: On referral, visual acuity was 20/400 in the right eye and 20/25 in the left eye. The affected right eye displayed a pigmented mushroom-shaped ciliary body mass with anterior chamber invasion, distorting the pupil and occupying 40% of the anterior chamber. Ultrasound biomicroscopy and B-scan ultrasonography revealed many cavities within the 14-mm-thick mass, suggestive of ciliary body melanoma. After enucleation, histopathology disclosed multiple cavities, some with granular eosinophilic material, within a mushroom-shaped mixed-cell melanoma. CONCLUSION: Cavitation can occur in ciliary body melanoma and can lead to misinterpretation as a cyst. Cavitary melanoma should be considered in the differential diagnosis of cystic lesions of the anterior segment.