A monoclonal antibody raised against an undecapeptide sequence from human transforming growth factor alpha recognizes a hexapeptide epitope in mitotic centrosomes.

A monoclonal antibody (mAbIIa138) raised against the second-loop undecapeptide (residues [21-31]) of human transforming growth factor alpha, known to be involved in binding to its cell receptor, was found to define a hexapeptide epitope (RFLVQE, residues [22-27]). In enzyme-linked immunosorbent assay testing mAbIIa138 did not react with either native or reduced human transforming growth factor alpha, indicating that conformational restraints in this protein interfered with the antigenicity of the cognate sequence. Despite its failure to react with human transforming growth factor alpha, this monoclonal antibody proved very interesting when used to immunostain mammalian cells. mAbIIa138 was found to bind with great specificity to the centrosomes of late-interphase and mitotic cells. The staining of the centrosomes was most intense when the centrosomes were active in organizing the mitotic spindle and faded during telophase as the spindle was disaggregated. The epitope that mAbIIa138 recognizes is thus in a centrosomal protein, denoted CSP alpha, involved in some aspect of mitotic spindle organization or function. Analysis of the antigenic stringency of the epitope, using an amino acid replacement set, showed that 25 individual single amino acid replacements were possible without significant loss of antigenicity. Data bank searches for proteins of possible relevance were unsuccessful, so CSP alpha is an as yet unsequenced protein, specific to the centrosome.     

IgM antitrophoblast antibodies in a patient with a pregnancy-associated lupuslike disorder, vasculitis, and recurrent intrauterine fetal demise

We describe herein circulating IgM antitrophoblast antibodies in a patient with recurrent pregnancy-associated vasculitis and intrauterine fetal demise. The patient also exhibited a lupus anticoagulant. Direct and indirect immunofluorescence studies were carried out with the patient's placenta, normal placentas, the patient's serum, and normal serum controls. The antitrophoblast antibodies may have contributed further to the risk of intrauterine death, already known to be associated with lupus anticoagulants. More information about the frequency of such antibodies is desirable and could be obtained in similar cases by the methods discussed.     

Assessment of abstracts submitted for the 1998 BNMS annual meeting: concordance or lottery?

The selection of abstracts for presentation at the Annual Meeting of the British Nuclear Medicine Society is an arduous task for the assessors. It is only to be expected that assessors' appreciation of an abstract will be biased by their interests and knowledge. This study assessed the concordance between the marks awarded by specialist and general assessors for the 173 abstracts submitted to the 1998 Spring BNMS meeting. The results showed considerable agreement among the markers for most comparisons. We conclude that the current combination of specialist assessors evaluating specific sections and three generalists assessing all abstracts appears to be working well.     

Snail shape and growth rates: Evidence for plastic shell allometry in Littorina littorea

The periwinkle Littorina littorea exhibits morphological variation among southern New England populations that appear to be genetically continuous. In dense populations, individuals have relatively elongate shells in comparison to individuals in sparse populations, which have rounder, globose shells. We experimentally demonstrate that this shell variation is a function of snail growth rate. Rapidly growing snails develop thin, globose shells that accommodate more body mass than thicker, more elongate shells. The implications of these results are discussed in relation to interpreting morphological variation in extant gastropods and in the molluscan fossil record.     

Optimal detection of the alpha state in a model of the human electroencephalogram

A mole of the EEG with waxing, waning and blocking alpha rhythm is described. One parameter is time dependent and simulates the "physiological alpha state' of the EEG generating network. A theoretically optimal detector of this state appears to be prescribed by the model and the statistics of the alpha state parameter. It minimizes the expected false decision rate.     

Primary bone tumors. MR morphologic appearance correlated with pathologic examinations.

Eighty-three MR studies for primary bone tumors, performed with both spin echo and short time inversion recovery (STIR) sequences, were reviewed. Twenty-six patients underwent surgery within 10 days after MR imaging. Specimens were cut and directly compared with MR images. In the remainder, pathologic slides were compared in order to obtain a better understanding of MR pattern. All MR images were examined with a traditional morphologic approach and, upon comparison with surgical macroslides and with pathology samples, some MR distinctive patterns were identified: the bulky appearance of osteosarcoma surrounded by muscle edema, the multilobular high signal intensity (SI) chondroid lesions, the subtle infiltration of Ewing's sarcoma, rarely accompanied by muscle edema and prone to MR underestimation, the well defined "multiple shells" pattern of giant cell tumor, and the ill defined "storiform" appearance of malignant fibrous histocytoma are all typical MR features strictly corresponding to pathologic findings. The chondroid origin tumors may be identified based on the lobular high SI pattern whereas a benign fibrous lesion was the only one in this series to be distinguished relying on the SI. Peritumoral soft tissue edema was found by the STIR sequence only in malignant tumors (69%) of this series, and particularly in osteosarcoma (96%), chondrosarcoma (83%), and giant cell tumor (100%): this associate finding may further contribute to the diagnosis.