The synthesis and localization of alternatively spliced fibronectin EIIIB in resting and thrombin-treated megakaryocytes

There are several species of alternatively spliced fibronectin (FN). One of these, FN EIIIB, is primarily present in embryonic and in proliferating and migrating cells and is believed to be important for cell maturation. We have studied the synthesis, localization, and secretion of this FN isoform in isolated guinea pig megakaryocytes, nonmegakaryocytic bone marrow cells, and platelets. There was 7.5 times more general FN in megakaryocytes than in nonmegakaryocytic cells based on the analysis of equivalent amounts of protein. FN EIIIB was detected by Western blotting in megakaryocytes but not in nonmegakaryocytic cells present in bone marrow. Neither megakaryocytes nor platelets secreted FN EIIIB, while megakaryocytes secreted 25.3% +/- 4.6% general FN and platelets secreted about 61% general FN in response to thrombin. Analysis of immunostained cells by confocal microscopy revealed that FN EIIIB had been redistributed to the surface of megakaryocytes in response to thrombin. Synthesis was studied by metabolic labeling, and megakaryocytes were shown to synthesize FN and FN EIIIB. Thus, megakaryocytes and platelets are among a small number of adult cells and tissues that synthesize and contain FN EIIIB. The expression of FN EIIIB on the megakaryocyte surface may influence migration and maturation.     

Becoming a mother — an analysis of women's experience of early motherhood

This paper presents the results of a qualitative study conducted by midwife researchers into women's experience of new motherhood. Data were collected using focus groups involving 55 first-time mothers and analysed using grounded theory method. The analysis produced six categories: 'realizing', 'unready', 'drained', 'aloneness', 'loss' and 'working it out'. The core category, 'becoming a mother', integrates all other categories and encapsulates the process of change experienced by women. Also explained are factors mediating the often distressing experience of becoming a mother. The analysis provides a conceptualization of early motherhood enabling the development of strategies for midwives, nurses and others helping women negotiate this challenge.     

Indapamide inhibits endothelium-dependent contractions in the aorta of the spontaneously hypertensive rat

Summary— Experiments were designed to determine whether or not indapamide, an antihypertensive agent with vasodilator properties, inhibits endothelium-dependent contractions. Rings of aortae with and without endothelium from spontaneously hypertensive rats (SHR) were suspended in conventional organ chambers for the measurement of isometric force. Acetylcholine and adenosine diphosphate-β-S in the presence of a nitric oxide synthase inhibitor, caused endothelium-dependent contractions, which were inhibited by indapamide. The compound (10⁻⁴M) also slightly reduced the contractions of rings without endothelium evoked by U-46,619, which activates thromboxane-endoperoxide receptors. These results demonstrate that indapamide inhibits endothelium-dependent contractions in the SHR aorta, and suggest that the inhibition is due, at least in part, to the action of the drug on the hypertensive vascular smooth muscle.     

SKALP/elafin gene polymorphisms are not associated with pustular forms of psoriasis

Psoriasis is a multifactorial skin disease characterised by epidermal abnormalities and infiltration by lymphocytes and polymorphonuclear leukocytes (PMN). Skin-derived antileukoproteinase (SKALP), also known as elafin, is a potent inhibitor of human leukocyte elastase and proteinase 3, two PMN-derived proteinases implicated in tissue destruction and leukocyte migration. We have shown that, at least at the protein level, SKALP is significantly decreased in lesional skin of patients with pustular psoriasis compared with plaque-type psoriasis. This finding raised the possibility that SKALP could be one of the candidate genes for pustular forms of psoriasis. We therefore performed single strand conformation polymorphism (SSCP) analysis on the SKALP gene to screen for mutations/polymorphisms in the exons of 30 patients with plaque-type psoriasis, 15 patients with pustular psoriasis and 48 healthy controls. In exon 1 a polymorphism was detected at position + 43 relative to the translation start site, resulting in a substitution of threonine for alanine in the signal peptide. In the promoter region a dinucleotide repeat polymorphism was identified. Both polymorphisms were not associated with pustular psoriasis, or psoriasis in general. Our data indicate that the decrease in SKALP activity in pustular psoriasis is not caused by mutations in the coding region of the gene, and that there is no allelic association between pustular psoriasis and SKALP gene polymorphisms.     

The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region

We have recently reported isolation of the gene responsible for X- linked Opitz G/BBB syndrome, a defect of midline development. MID1 is located on the distal short arm of the human X chromosome (Xp22. 3) and encodes a novel member of the B box family of zinc finger proteins. We have now cloned the murine homolog of MID1 and performed preliminary expression studies during development. Mid1 expression in undifferentiated cells in the central nervous, gastrointestinal and urogenital systems suggests that abnormal cell proliferation may underlie the defect in midline development characteristic of Opitz syndrome. We have also found that Mid1 is located within the mouse pseudoautosomal region (PAR) in Mus musculus , while it seems to be X- specific in Mus spretus. Therefore, Mid1 is likely to be a recent acquisition of the M. musculus PAR. Genetic and FISH analyses also demonstrated a high frequency of unequal crossovers in the murine PAR, creating spontaneous deletion/duplication events involving Mid1. These data provide evidence for the first time that genetic instability of the PAR may affect functionally important genes. In addition, we show that MID1 is the first example of a gene subject to X-inactivation in man while escaping it in mouse. These data contribute to a better understanding of the molecular content and evolution of the rodent PAR.      

Variations in strength of vertebrae with age and their relation to osteoporosis

Fourth and fifth lumbar vertebrae were obtained at post mortem examinations of human subjects in the range 26 to 86 years and at the same time specimens were taken from the iliac crests for histological assessment of trabecular density (iliac crest score). After removal of pedicles and spinous processes the vertebrae were compressed in a testing machine to mechanical failure. The following values were obtained; breaking stress (load per unit area at failure), strain (percentage deformation) at failure and relative ash content (ash per unit volume). Strain at failure was independent of the size and strength of the vertebrae. The relative ash content and the iliac crest score were closely correlated. The relative ash content and the breaking stress both declined with increasing age, but the relation between them was not linear since the breaking stress fell more quickly than the ash content. Euler's equation for the buckling stress of a loaded column readily explains how in osteoporosis the reduction of the diameter of the vertical trabeculae and the loss of transverse ties cause loss of strength proportionately greater than the loss of osseous tissue. The results give no reason to suppose that in osteoporosis the quality of the osseous tissue is changed.

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Zusammenfassung Die vierten und fünften Lumbalwirbelknochen wurden von Obduktionen menschlicher Leichen innerhalb der Altersgrenzen von 26 und 86 Jahren gewonnen. Gleichzeitig wurden Proben von der Beckenschaufel entnommen, um Maßstäbe für die Bälkchendichte festzulegen (Beckenschaufelzahl). Nach Entfernung der Ansätze und Dornfortsätze wurden die Wirbelknochen in einer Prüfungsmaschine komprimiert, um mechanisches Versagen zu bestimmen. Folgende Werte wurden erhalten: Bruchbelastung (Gewicht pro Einheitsfläche bei Bruch), Beanspruchung (Prozentsatz von Deformation) bei Bruch und relativer Aschegehalt (Asche pro Einheitsvolumen). Die Beanspruchung bei Bruch war unabhängig von Größe und Stärke der Wirbelknochen. Zwischen dem relativen Aschegehalt und der Beckenschaufelzahl bestand eine enge Verbindung. Der relative Aschegehalt und die Bruchbelastung wurden mit fortschreitendem Alter kleiner, jedoch war die Beziehung zwischen diesen beiden Faktoren nicht linear, da die Bruchbelastung rascher als der Aschegehalt abnahm. MitEulers Gleichung für die Verbiegungsbelastung einer geladenen Säule läßt sich leicht erklären, auf welche Weise bei der Osteoporose die Reduktion des Durchmessers der Wirbeltrabekeln und der Verlust der transversen Verbindungen einen verhältnismäßig größeren Stärkeverlust hervorruft, als durch Verlust von Knochengewebe erklärt werden kann. Die Ergebnisse geben keinen Anlaß zu der Vermutung, daß bei der Osteoporose die Qualität des Knochengewebes eine Veränderung erfährt.

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Résumé Les quatrième et cinquième vertèbres lombaires sont prélevées post-mortem chez des sujets humains, âgés de 26 à 86 ans, et des échantillons de crête iliaque sont collectés simultanément pour établir histologiquement la densité des travées osseuses (index de la crête iliaque). Après avoir enlevé les pédicules et les apophyses épineuses, les vertèbres sont compressées dans une machine pour tester la résistance mécanique. Les valeurs suivantes sont déterminées: force de rupture (en poids par unité de surface au moment de la rupture), effort de rupture (en pourcentage de déformation) et contenu relatif en cendres (en cendres par unité de volume). L'effort de rupture est indépendant de la taille et de la force des vertèbres. Le contenu relatif en cendres et l'index de la crête iliaque sont en rapports étroits. Le contenu relatif en cendres et la force de rupture diminuent en fonction de l'âge, mais ce rapport n'est pas linéaire, car la force de rupture chute plus rapidement que le contenu en cendres. L'équation d'Euler pour une force courbe appliquée à une colonne chargée explique facilement comment, dans l'ostéoporose, la réduction de diamètre des travées verticales et la perte des attaches transversales sont responsables de la perte de force proportionellement plus élevée que la perte de tissu osseux. Les résultats ne permettent pas de supposer que, dans l'ostéoporose, la qualité du tissu osseux est altérée.

     

The use of natural interferon alpha conjugated to a monoclonal antibody anti mammary epithelial mucin (Mc5) for the treatment of human breast cancer xenografts

Summary An immunoconjugate composed of natural interferon (nIFN) bound in a noncleavable fashion to a monoclonal antibody (MoAb) recognizing a breast epithelial membrane mucin (Mc5) was used to treat xenografts of a human mammary carcinoma cell line (MCF-7) growing in nude mice. The immunoconjugate (nIFN/Mc5) was administered as 20 intralesional (i.l.) injections to 1 of 2 xenografts in each animal. It was found that nIFN/Mc5 produced a significant enhancement of the growth inhibitory actions of nIFN on the injected tumors. Further enhancement was obtained when nIFN or nIFN together with Mc5 (at a dose 10 times larger than that present in nIFN/Mc5) were added to the immunoconjugate. Biodistribution experiments showed that the uptake of¹²⁵I-nIFN/Mc5 by the tumors was greater and its elimination slower than for¹²⁵I-nIFN alone or conjugated to irrelevant mouse IgG₁. In addition, the immunoconjugate up-regulated the antigenic expression of a breast epithelial membrane mucin by the carcinoma cells, an up-regulation which was not significantly different from that produced by nIFN alone. The contralateral noninjected tumors exposed to systemic levels of the immunoconjugate showed an enhancement of antitumor effects, but to a lesser extent than the injected tumors. These findings suggest that the enhancement of the growth inhibitory action of the immunoconjugate was related to the specific binding of Mc5 which targeted the IFN to the carcinoma cells and impeded its elimination. It is likely that the targeting was favored by the IFN-mediated up-regulation of antigenic expression by the carcinoma cells, thereby producing a cascade of interrelated effects. The results of this study point out the feasibility and potential usefulness of IFN treatment by means of immunoconjugates as well as the worth of pursuing and improving this form of therapy.     

EFFICACY OF SUCRALFATE IN PREVENTING GASTROINTESTINAL SIDE EFFECTS OF NSAIDs

To find out the efficacy of sucralfate in preventing gastrointestinal side effects of non-steroidal anti-inflammatory drugs (NSAIDs) a prospective, randomised single blind study was conducted from 1989 to 1992. Patients with osteoarthritis, rheumatoid arthritis and other long standing painful conditions, who were expected to receive NSAIDs for over three months, were recruited into the study. All medicines were discontinued for a period of 10–15 days prior to initial endoscopic assessment. NSAID therapy was started and the patients were randomised to receive either placebo (group A) or sucralfate (group B) in addition. Patient were reassessed clinically every week and an endoscopic examination was repeated after 6–8 weeks of follow-up. A total of 176 patients were studied in group A (n=91) and group B (n=85). At the end of 8 weeks gastrointestinal symptoms were present in 30.6% and 26.4% patients of group A and B respectively. Endoscopic assessment showed superficial lesions in 36.5% and 18.7% while endoscopic ulcer in 2.4% and 1.1% patients of groups A and B respectively. Thus in patients receiving chronic NSAID therapy, simultaneous administration of sucralfate reduces the incidence of superficial gastric lesions but has no significant effect on symptoms or ulcer formation.KEY WORDS: Gastropathy, Sucralfate, Nonsteroidal anti-inflammatory drugs