New stand magnifiers do not meet rated levels of performance

A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'_v) rather than equivalent dioptric power (F_m) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use.     

MRP8 and MRP14, S-100-like proteins associated with myeloid differentiation, are translocated to plasma membrane and intermediate filaments in a calcium-dependent manner

MRP8 and MRP14 are two Ca(2+)-binding proteins of the S-100 family expressed by myelomonocytic cells. Both proteins assemble to noncovalently associated complexes in a Ca(2+)-dependent manner. Members of the S-100 family are known to play a role in cytoskeletal- membrane interactions; therefore, we investigated the subcellular distribution of MRP8/MRP14 and their complexes in human monocytes. Using differential centrifugation and subsequent Western blot or enzyme- linked immunosorbent assay analysis, we found that MRP8/MRP14 were almost completely translocated from the cytoplasma to membrane and cytoskeletal structures in a Ca(2+)-dependent manner. Using a cross- linking technique, complexed forms of MRP8/MRP14 were found to be associated with the plasma membrane. Analysis of MRP-transfected L132 cells showed that the MRP8 as well as the MRP14 component of the MRP8/MRP14 complex may independently bind to membrane and cytoskeletal structures. Furthermore, immunogold electron microscopy showed a colocalization of MRP8/MRP14 and the intermediate filament type III protein vimentin in A23187-treated monocytes. Our data indicate that, in analogy to other S-100-like proteins, MRP8 and MRP14 play a role in Ca(2+)-dependent cytoskeletal-membrane interactions. Restriction of MRP8/MRP14 expression to distinct stages of myelomonocytic differentiation suggests that these proteins are involved in highly specific pathways of intracellular signaling in phagocytes.     

Down-regulation of tenascin expression by antiprogestins during terminal differentiation of rat mammary tumors.

Studies on tenascin expression in hormonally dependent growing tissues of breast and endometrium suggested that its expression parallels the progression of normal or malignant proliferative alteration of the tissue. With the study presented here we addressed the question of whether antiprogestin-induced terminal differentiation down-regulates tenascin expression. By comparative immunolocalization of tenascin in sections of untreated 7,12-dimethylbenz[alpha]anthracene-induced tumors, tumors grown in ovariectomized animals, tamoxifen-treated tumors, and antiprogestin-treated tumors, we obtained the following results. (a) The entire extracellular space of the stromal mesenchyme was filled by tenascin immunoreactivity in cases of untreated control tumors. (b) Both ovariectomy and antiestrogen treatment with tamoxifen did not affect the overall staining pattern and resulted in a slight increase of the arbitrarily judged staining intensity. (c) Within antiprogestin-treated tumors tenascin-like immunoreactivity predominantly was restricted to fiber-like, collagenous connective tissue structures, which appeared in the stromal compartment as a result of the antiprogestin treatment. In large areas of the tumor composed of apparently secretory active tumor cells we failed to immunolocalize tenascin. Our results provide further evidence that expression of tenascin reflects both benign and malignant proliferative alterations of the tissue, whereas its down-regulation is correlated to differentiation of the tissue. Additionally, evidence is provided that the mechanism of tumor growth inhibition by antiprogestins indeed is induction of terminal differentiation of tumor cells.     

Does the single-breath N2 test identify the smoker who will develop chronic airflow limitation?

We report here the results of a 9- to 11-yr follow-up of 2 cohorts in which spirometry and the single-breath N2 test were used throughout the follow-up period to determine the usefulness of the single-breath N2 test in identifying the smoker who is experiencing a rapid decline in FEV1 and is therefore likely to be at risk of developing chronic airflow limitation. The analyses are based on 734 subjects tested from 3 to 5 times over the follow-up period; 82 smokers developed an abnormal FEV1 during the follow-up period. Of these, 71 (87%) had had an abnormal single-breath N2 test at some time prior to the FEV1 becoming abnormal. Of the single-breath N2 test variables, CC/TLC was the only one significantly associated with the rate of decline of FEV1 in both cohorts once adjustments were made for age, sex, height, and smoking. We conclude that the single-breath N2 test can be useful in identifying the smoker who is at risk of developing chronic airflow limitation. However, its usefulness is diminished by the high proportion of smokers who have mild functional abnormalities but do not progress to develop chronic airflow limitation. We also find that the single-breath N2 test does not appear to have a useful predictive value in nonsmokers.     

Quantitative determination of oestradiol-17 beta hydroxysteroid dehydrogenase: increased sensitivity by HPLC separation of the hormones permits the measurement of enzyme activity in cryostat sections

The activity of the oestradiol-17 beta hydroxysteroid dehydrogenase in human endometrial and breast cancer specimens was determined by the NAD-dependent conversion of oestradiol-17 beta to oestrone. The sensitivity of the determination was improved by the separation of the hormones by HPLC. We are now able to determine oestradiol-17 beta hydroxysteroid dehydrogenase quantitatively in cryostat sections. A clear correlation of serum progesterone levels and oestradiol-17 beta hydroxysteroid dehydrogenase activity in the endometrium was demonstrated, and we found a more than 30-fold increase in enzyme activity after the progesterone surge. In contrast, in breast cancer samples, we found no correlation between oestradiol-17 beta hydroxysteroid dehydrogenase and the measured serum parameters.     

Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy

To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice.