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In order to identify neuroendocrine tumour-specific protein expression, we generated monoclonal antibodies (mAbs) with a tumour-related reaction pattern using a human insulinoma as immunogen. One of the generated mAbs (mAb 1D4) exhibited striking immunoreactivity against various neuroendocrine tumours without staining pancreatic islets of Langerhans. Furthermore, mAb 1D4 immunostained a characteristic subtype of hypothalamic neurones. Using two-dimensional (2-D) gel electrophoresis, mAb 1D4 immunoblotting and mass spectrometry, heat shock protein 70 (Hsp70) isoforms were identified as the mAb 1D4-specific antigen. In hypothalamic tissue, the presence of two different Hsp70 isoforms (Hsp70-8 and Hsp70-1) was revealed by 2-D gel immunoblots and consecutive mass spectrometric peptide analysis. In contrast, insulinoma and other neuroendocrine tumours displayed solely Hsp70-8 expression. Moreover, the tumour-specific presence of an additional mAb 1D4 immunoreactive protein of 40 kDa was observed in eight out of eight tested neuroendocrine tumours. For this variant, exclusively, peptides derived from the C terminus excluding the 299 amino-terminal residues were detected. In cultured tumour-derived fibroblasts, expression of the truncated Hsp70-8 subtype was not present. In conclusion, we have demonstrated a neuroendocrine tumour-specific expression pattern of Hsp70 isoforms and identified an as yet unknown N-terminally truncated Hsp70-8 variant.

Laser-induced optoacoustic spectroscopy (LIOAS) was applied to the study of 13-cis (13RT), 11-cis (11RT), and all-trans (trRT)-retinal photoisomerization in various n-alkanes. From the analysis of the LIOAS data in aerated and N2-saturated solutions of the three isomers, it is concluded that their triplet states undergo different relaxation pathways. Whereas trRT and 11RT produce long-lived triplet states that are quenched by oxygen, yielding O2(¹Δg) with high efficiency, the 13RT triplet rapidly releases its excess energy by isomerization to the trRT isomer. Direct measurement of the near-IR emission from O2(¹Δg) supports these conclusions. The quantum yield for O2(¹Δg) production is 0.61 ± 0.05 for trRT, 0.27 ± 0.05 for 11RT (in each case similar to the respective yield of triplet formation, as detected by LIOAS), and <0.15 for the 13RT isomer (i.e., much smaller than its triplet yield). With this combination of techniques and the use of literature data, it was possible to elucidate the role of the triplet state in the photoisomerization reaction, which turned out to be different for each retinal isomer:  the trRT triplet is nonreactive and loses all its excess energy by intersystem crossing to the ground state, the 11RT triplet isomerizes to the trRT triplet, and the 13RT triplet isomerizes to the trRT ground state. Furthermore, the LIOAS data for 13RT appear to be solvent dependent in the range from n-pentane to n-hexadecane, which might be interpreted in terms of a structural volume change for the cis → trans (13RT → trRT) photoisomerization. Depending on the interpretation of the data, a contraction with a value between 33 and 130 mL/mol was calculated. However, the validity of this analysis was difficult to establish, and alternative explanations of the solvent dependence such as a variation of the isomerization quantum yield could not be ruled out, due to the intrinsic, relatively large error of the quantum yield determination.

Taking the purpose of refraction to be the achievement of comfortable, normal binocular stereoscopic vision with some amplitude of stereopsis, it is necessary to measure the degree of success. Tests using polarisation fulfil the criteria for such a test to a greater extent than any other group of binocular tests. This paper describes and lists tests using polarisation for near visual examination and static refraction.

The design theory of the depletion layer transistor, which was first announced at WESCOX, 1956,’ is outlined in all its major phases. The schematic models on which the analysis is based are presented, and the fundamental equations, which describe the carrier transport through the proposed structures, are formulated. Among the results to be discussed are expressions for available gain and an analysis of the stability problem. The theory is extended to describe operation at frequencies equal to or exceeding the reciprocal transit time of carriers through the structure.