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Copyright of Computing is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the first polar lobe of Bithynia eggs a special plasm, the vegetal body, is present. It consists of a cupshaped aggregate of small vesicles. Centrifugation of eggs prior to first cleavage may result in displacement of the vegetal body. In about 50% of thecentriguged eggs the vegetal body is found outside the polar lobe, in one of the blastomeres. Removal of the polar lobe from non-centrifuged eggs always leads to severe defects in development. When the lobe is removed from centrifuged eggs, however, about 50% of the eggs develop into normal embryos. It is concluded that the presence of the vegetal body in a blastomere suffices to ensure normal development and, hence, that the polar lobe-specific morphogenetic determinants are contained within the vegetal body. [ABSTRACT FROM AUTHOR]

The significance of the first quartet of micromeres for the morphogenesis of Bithynia - a polar lobe-forming gastropod-has been studied by deletion experiments. After removal of the whole first quartet at the 8-cell stage a dorsoventrally organized veliger larva is formed. Apparently, an interaction between the animal micromeres and a vegetal macromere, which is essential for the origin of a dorsoventral organization in equally cleaving gastropods, is not required in polar lobe forming eggs. It is concluded that in these eggs dorsoventrality is determined by segregation of the polar lobe. The embryos, in which the first quartet has been removed, never develop head structures. This indicates that the capacity to form head structures is restricted to the first quartet of micromeres. Deletion of a specific first quartet micromere (1a, 1b, 1c or 1d) showed, however, that the individual cells of this quartet are not strictly determined right from their origin. Frequently regulative development was observed after removal of individual first quartet cells. [ABSTRACT FROM AUTHOR]

Randomly generated polytopes are used frequently to test and compare algorithms for a variety of mathematical programming problems. These polytopes are constructed by generating linear inequality constraints with coefficients drawn independently from a distribution such as the uniform or the normal. It is noted that this class of 'random' polytopes has a special property: the angles between the hyperplanes, though dependent on the specific distribution used, tend to be equal when the dimension of the space increases. Obviously this structure of 'random' polytopes may bias test results. [ABSTRACT FROM AUTHOR]

A total of 61 lumbar sympathetic blockades were performed on 5 patients with gangrene on one or several toes and on 6 patients with intermittent claudication only. Subcutaneons blood flow on the dorsum of the foot was measured by the Xenon clearance technique before and after the blockades. In the gangrene group successful lumbar blockades resulted in a significant decrease in the blood flow from 7.4 ml/100 g/min to 5.5 mI/100 g/min while in the patients only suffering from intermittent claudication a significant increase in the blood flow from 3.4 ml, 100 g/min to 4.7 ml/100 g/min was found. Additional observations suggested that measurement of skin temperature and the sympathogalvanic reflex are not adequate criteria for selecting those patients in which lumbar sympathetic blockades produces an increased peripheral blood flow. The indications for sympathetic denervation in patients with arterial obstructions are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Calcified Tissue Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To determine the effect of topically applied amelogenin extracellular matrix protein (AEMP) in patients with non-healing venous leg ulcers combined with atrophie blanche. Method: This retrospective case series of patients with non-healing venous leg ulcers with atrophie blanche of the distal proportion of their lower legs, where non-healing was defined as no progress toward healing for 3 months previously, under standard therapy. Patient records were reviewed for associated diseases, wound diagnoses, distal blood pressure, previous treatments and changes in wound area. Patients were treated with AEMP once a week, for a period of 12 weeks, or until full healing. l Results: Eleven patient records were reviewed retrospectively. The median age of the patients was 81 years (range 40-95 years), with a mean wound size of 4.7 ± 3.5cm2 and median wound duration of 6 months (range 3-444 months). All patients had venous or combined arterial/venous insufficiency. After 12 weeks' treatment with AEMP, complete healing, defined as 100% re-epithelialisation, was documented in four patients (36%), marked improvement (> 50% epithelialisation) in three patients (54%, 55% and 83% wound closure, respectively), slight improvement in one patient (9.4% wound closure), no change for two patients and worsening in one. AEMP was well tolerated, and no patients reported side effects. Conclusion: The results of this retrospective study suggest that AEMP improves healing in chronic venous leg ulcers combined with atrophie blanche. Declaration of interest: Amelogenin extracellular matrix protein (XelmaR) was provided by Mölnlycke Health Care, Denmark. There were no external sources of funding for this study and Mölnlycke Health Care had no role in the study design or data collection. The authors have no conflicts of interest to declare. [ABSTRACT FROM AUTHOR]